KR102630308B1 - Manufacturing method of adhesive sheet and semiconductor device - Google Patents

Abstract

An adhesive sheet (10) for processing electronic components, which has a base material (11) and an adhesive layer (12), wherein the adhesive layer (12) contains a cured product of an energy ray curable component.

Description

Manufacturing method of adhesive sheet and semiconductor device

The present invention relates to a method of manufacturing an adhesive sheet and a semiconductor device.

In the manufacturing process of semiconductor devices, adhesive sheets are used for the purpose of protecting semiconductor elements (for example, semiconductor chips, etc.). Various properties are required for adhesive sheets used in the manufacturing process of semiconductor devices.

For example, Patent Document 1 describes a heat-resistant adhesive tape including a base material layer and an adhesive layer formed on the base material layer. The heat-resistant adhesive tape described in Patent Document 1 has an adhesive layer composed of an ultraviolet curable adhesive containing an ultraviolet curable compound, and the adhesive layer is irradiated with ultraviolet rays and heated at 200° C. for 1 hour in accordance with JIS Z0237. It is described that the measured adhesive force of the adhesive layer is 1 N/19 mm width or less.

Additionally, Patent Document 2 describes an adhesive sheet having a base material and an adhesive layer containing an energy ray-curable adhesive formed on the base material.

In addition, in recent years, adhesive sheets have less problems with adhesive remaining on the adherend (so-called glue residue) when peeling off at room temperature after going through a process that imposes high temperature conditions, and the peeling force is also low. It is being demanded.

For example, Patent Document 3 describes a heat-resistant adhesive tape that is used to adhere and use when resin-sealing a semiconductor chip mounted on a metal lead frame. The heat-resistant adhesive tape described in Patent Document 3 has at least a base material layer and an active energy ray-curable adhesive layer.

Japanese Patent Publication No. 2012-46763 Japanese Patent Publication No. 2017-82104 Japanese Patent Publication No. 2010-73853

The adhesive tapes and adhesive sheets (hereinafter collectively referred to as “adhesive sheets”) described in Patent Documents 1 and 2 are constructed so that the adhesive strength of the adhesive layer decreases when irradiated with ultraviolet rays, so that the adhesive sheet can be relatively easily removed from the adherend. can be peeled off.

According to Patent Document 3, it is stated that the heat-resistant adhesive tape described in the document can be easily peeled without any glue remaining at the time of peeling. Patent Document 3 describes that the timing for curing the active energy ray-curable adhesive layer is not particularly limited as long as it is after bonding but before the wire bonding process. For the reason, Patent Document 3 states that if the adhesive layer is cured before bonding to the outer pad side of the lead frame, the effect of following the unevenness of the lead frame surface is not obtained, and the adhesive strength decreases, making bonding difficult, and , it is described that it is difficult to prevent leakage of the encapsulating resin because the adhesion to the lead frame is reduced.

However, when an adhesive tape containing an active energy ray-curable adhesive in the adhesive layer as described in Patent Documents 1, 2, and 3 is used in the manufacturing process of a semiconductor device, the adhesive tape is separated from the adherend under a high temperature environment in the encapsulation process. There may be cases where it peels off or swells (blisters). Additionally, when a plasma treatment process is performed following the encapsulation process, problems such as expansion (blistering) between the adhesive tape and the adherend may occur due to a temperature increase due to heating or a process in which temperature increase and pressure decrease simultaneously. There are cases.

The purpose of the present invention is to reduce the occurrence of expansion and unintentional peeling from the adherend under high temperature or high temperature and reduced pressure conditions, improve the adhesive force when heated, and maintain glue when peeled from the adherend. The goal is to provide an adhesive sheet that can prevent.

Another object of the present invention is to provide a semiconductor device manufacturing method for manufacturing a semiconductor device using the adhesive sheet.

The adhesive sheet according to one aspect of the present invention has a base material and an adhesive layer, and the adhesive layer contains a cured product of an energy ray curable component.

In the pressure-sensitive adhesive sheet according to one aspect of the present invention, the pressure-sensitive adhesive layer further includes a polymer component, and the polymer component includes a structural unit derived from a monomer having a nitrogen-containing functional group, provided that the nitrogen-containing functional group It is preferable that it does not contain an N-H bond.

In the pressure-sensitive adhesive sheet according to one aspect of the present invention, the polymer component includes a structural unit derived from a functional group-containing monomer having a reactive functional group, and the reactive functional group includes three or more methylene groups bonded in a linear chain. It is preferable to bind to the main chain of the polymer component through an interposition.

In the pressure-sensitive adhesive sheet according to one aspect of the present invention, the energy ray-curable component includes a polyfunctional energy ray-curable compound, and the polyfunctional energy ray-curable compound has 2 to 5 polymerizable compounds per molecule. It is preferable that it is a bifunctional energy ray curable compound having a functional group.

In the pressure-sensitive adhesive sheet according to one aspect of the present invention, the energy ray-curable component includes a polyfunctional energy ray-curable compound, and the polyfunctional energy ray-curable compound has two or more polymerizable functional groups in one molecule, There is a methylene group bonded in a straight chain between the first polymerizable functional group and the second polymerizable functional group arbitrarily selected from two or more polymerizable functional groups of the multifunctional energy ray curable compound, and the first polymerizable functional group and the above It is preferable that the number of linearly bonded methylene groups present between the second polymerizable functional groups is 4 or more.

In the pressure-sensitive adhesive sheet according to one aspect of the present invention, it is preferable that the number of linearly bonded methylene groups present between the first polymerizable functional group and the second polymerizable functional group is 8 or more and 30 or less.

In the adhesive sheet according to one aspect of the present invention, the polyfunctional energy ray-curable compound preferably has a cyclic structure in the molecule.

In the pressure-sensitive adhesive sheet according to one aspect of the present invention, it is preferable that the pressure-sensitive adhesive layer has a breaking strength per unit cross-sectional area of 4.5 N/mm2 or more.

In the adhesive sheet according to one aspect of the present invention, it is preferable that the adhesive strength of the adhesive sheet to polyimide at 100°C is 0.04 N/25 mm or more.

In the adhesive sheet according to one aspect of the present invention, the adhesive strength of the adhesive sheet to polyimide at 100°C is 0.06 N/25 mm or more, and the breaking strength per unit cross-sectional area of the adhesive layer is 4.5 N/ It is desirable to have more than ㎟.

In the adhesive sheet according to one aspect of the present invention, the adhesive strength of the adhesive sheet to polyimide at 25°C after heat treatment at 190°C for 1.5 hours in a nitrogen atmosphere is preferably 3 N/25 mm or less. do.

In the adhesive sheet according to one aspect of the present invention, the Young's modulus of the adhesive layer is preferably 5 MPa or less.

In the adhesive sheet according to one aspect of the present invention, it is preferably used for fixing or protecting electronic components when processing them.

In the adhesive sheet according to one aspect of the present invention, the electronic component is a semiconductor element, and it is preferably used to fix the semiconductor element when sealing the semiconductor element.

In the adhesive sheet according to one aspect of the present invention, it is preferable that the electronic component is directly attached to the adhesive layer.

In the pressure-sensitive adhesive sheet according to one aspect of the present invention, the polymer component is preferably crosslinked by a crosslinking agent.

In the pressure-sensitive adhesive sheet according to one aspect of the present invention, the polymer component is preferably a (meth)acrylic polymer.

In the adhesive sheet according to one aspect of the present invention, the nitrogen-containing functional group is preferably at least one selected from the group consisting of a tertiary amino group, aminocarbonyl group, cyano group, and nitrogen-containing heterocyclic group.

In the pressure-sensitive adhesive sheet according to one aspect of the present invention, the monomer having the nitrogen-containing functional group is a heterocyclic vinyl compound, a (meth)acrylamide compound, an amino group-containing (meth)acrylic acid ester compound, and (meth)acrylonitrile. It is preferable that it is at least one type selected from the group consisting of.

In the adhesive sheet according to one aspect of the present invention, the proportion of structural units derived from the monomer having the nitrogen-containing functional group in the total mass of the polymer component is 1 mass% to 20 mass%. desirable.

In the adhesive sheet according to one aspect of the present invention, the proportion of the cured product obtained by curing the energy ray curable component to the total mass of the adhesive layer is preferably 5% by mass or more and 40% by mass or less.

A method for manufacturing a semiconductor device according to one aspect of the present invention includes the steps of fixing a semiconductor element on an adhesive sheet having an adhesive layer containing a cured product of an energy ray curable component, and attaching the semiconductor element using an encapsulant. A method of manufacturing a semiconductor device, including a process of encapsulating.

According to the present invention, in order to reduce the occurrence of expansion and unintentional peeling from the adherend under high temperature or high temperature and reduced pressure conditions, the adhesive strength when heated is improved, and the glue residue when peeled from the adherend is reduced. An adhesive sheet that can prevent this can be provided.

1 is a schematic cross-sectional view of an adhesive sheet according to the first embodiment.
Fig. 2 is a cross-sectional schematic diagram of the adhesive sheet according to the second embodiment.
Fig. 3 is a schematic cross-sectional view of the adhesive sheet according to the third embodiment.

Hereinafter, an adhesive sheet related to one aspect of the present invention will be described with reference to the drawings.

In addition, in this specification, “glue remaining” refers to the components in the adhesive layer, regardless of whether they are components mixed into the adhesive layer when the adhesive sheet is peeled from the adherend or components that penetrate into the adhesive layer after the adhesive layer is formed. This refers to a problem that causes residues to form on the adherend.

<First embodiment>

[Adhesive sheet]

1 shows a cross-sectional schematic diagram of the pressure-sensitive adhesive sheet 10 of this embodiment.

The mode of use of the adhesive sheet 10 is not particularly limited. An example of the use mode of the adhesive sheet 10 is an embodiment in which the adhesive sheet 10 is used as an adhesive sheet for electronic component processing. Moreover, another use mode of the adhesive sheet 10 includes an aspect in which it is used to fix or protect electronic components. Moreover, as a more specific aspect of using the adhesive sheet 10, an aspect in which the adhesive sheet 10 is used to fix the semiconductor element when sealing the semiconductor element is also mentioned.

Various members can be attached to the adhesive sheet 10. In this specification, a member that can be adhered to the adhesive sheet 10 may be referred to as an adherend. Examples of adherends include electronic components (semiconductor elements, etc.) and frame members. It is preferable that adherends such as electronic components are affixed directly to the adhesive layer 12. The frame member can be used, for example, when encapsulating semiconductor elements on the adhesive sheet 10 with an encapsulating resin, to prevent bending of the adhesive sheet 10 due to curing shrinkage of the encapsulating resin. The frame member may remain in the semiconductor package obtained after encapsulation of the semiconductor element and perform a predetermined function, and in other cases, the semiconductor package may be obtained only from the portion excluding the frame member.

The adhesive sheet 10 of this embodiment has a base material 11 and an adhesive layer 12. The adhesive layer 12 contains a cured product in which the energy ray curable component has been cured. In this embodiment, a release sheet RL may be further laminated on the adhesive layer 12. When using the adhesive sheet 10, the release sheet RL is peeled from the adhesive sheet 10.

The adhesive layer 12 includes a polymer component (hereinafter also referred to as “polymer component (A)”) and a cured product obtained by curing the energy ray curable component (hereinafter also referred to as “cured product (B)”). desirable.

The pressure-sensitive adhesive layer 12 in one aspect of the present embodiment includes a polymer component (hereinafter also referred to as “polymer component (AX)”) containing a structural unit derived from a monomer having a nitrogen-containing functional group, and energy ray curability. The component includes a cured product (also referred to as “cured product (B)”). However, the nitrogen-containing functional group does not contain an N-H bond.

The substrate 11 has a first substrate surface 11a and a second substrate surface 11b on the opposite side to the first substrate surface 11a. In the adhesive sheet 10 of this embodiment, the adhesive layer 12 is laminated on the first substrate surface 11a. To this adhesive layer 12, an adherend such as a semiconductor element is adhered. The adhesive layer 12 holds the adherend on the adhesive sheet 10 during the semiconductor device manufacturing process.

According to the adhesive sheet 10 of the present embodiment, in order to reduce the occurrence of expansion under high temperature and reduced pressure conditions and unintentional peeling from the adherend, the adhesive strength when heated is improved and when peeled from the adherend, Remaining of glue can be prevented (hereinafter also referred to as “the effect of this embodiment”).

The reason why the effect of this embodiment is obtained is assumed as follows.

The pressure-sensitive adhesive layer 12 according to the present embodiment contains a cured product (B) in which an energy ray-curable component has been cured. Therefore, even in a high temperature environment, the adhesive layer 12 can sufficiently maintain adhesive strength to the adherend. As a result, the adhesive sheet 10 can be fixed to the adhesive sheet 10 without the adherend falling off. The high-temperature environment in this specification is not particularly limited, but includes, for example, a process for encapsulating semiconductor elements, a process for sputtering metal or the like on electronic components, a process for cleaning electronic components with hot water, etc. there is. In this specification, the adherend to be adhered to the adhesive sheet is not particularly limited, but when the adhesive sheet is used in the encapsulation process of a semiconductor device, the material of the adherend may be the silicon surface of the semiconductor device or the material formed on the semiconductor device. A polyimide film, etc. can be mentioned. When a frame member is used when encapsulating a semiconductor element, the frame member can also be an adherend of the adhesive sheet 10, and examples of the material include glass epoxy resin. Moreover, examples of the adherend in applications of the adhesive sheet 10 other than the encapsulation process of semiconductor elements include glass wafers.

Additionally, in a process involving heating or heating and decompression, the pressure-sensitive adhesive sheet 10 and other members expand between the adhesive sheet and the adherend due to gas generation resulting from moisture absorbed during storage or the manufacturing process (Bliss). There are cases where this occurs. Since the adhesive sheet 10 has high adhesive strength even in high temperature or high temperature and reduced pressure environments, the generation of blisters and the like can be suppressed. Since the adhesive layer 12 has sufficient cohesiveness, it can be removed by peeling off the adhesive sheet 10 without generating a residue on the adherend after heating or a process involving heating and reduced pressure. there is. In this specification, heating or a process involving heating and reduced pressure is not particularly limited, but examples include a sealing process or a plasma treatment process following the sealing process. The adherend in the process involving heating or heating and reduced pressure is not particularly limited, and examples include semiconductor elements, frame members, and glass wafers.

After peeling the adhesive sheet from the adherend, residue adhering to the surface of the adherend may be referred to as glue residue. For example, during the manufacturing process of a semiconductor device, when the adhesive sheet is peeled from the encapsulant after the encapsulation process is completed, the adhesive may adhere to the conductive portion of the semiconductor device (semiconductor element). For example, the conductive portion may include a via portion of a semiconductor device or a frame member, and the conductive portion is formed of, for example, copper.

According to the adhesive sheet according to the present embodiment, it is possible to prevent the adhesive from adhering to the surface of copper even after it is heated in the encapsulation process, so that after peeling off the adhesive sheet after resin-sealing the semiconductor device. , it is possible to prevent glue remaining in the conductive part.

Unlike the polymer component (A), the cured product (B) is in an uncured (unreacted) state at the stage of raw materials for preparing the adhesive composition contained in the adhesive layer 12. The energy ray-curable component in the cured product (B) reacts after the adhesive layer 12 is formed from the adhesive composition, and a high molecular weight substance is synthesized and cured. Therefore, the cured product (B) exists continuously in the adhesive layer 12, and is different from that which exists discontinuously, such as an organic filler.

The adhesive layer 12 contains the cured product (B) that exists continuously in this way, so that a structure is formed in which the polymer component (A) penetrates into the three-dimensional network structure of the cured product (B), and the polymer component (A) It is thought that it is in a cross-linked state due to the loose restraint of the network-like structure. It is thought that this improves the cohesiveness of the adhesive layer at high temperatures, and achieves the effect of improving adhesive strength at the above-mentioned high temperature and the effect of preventing glue residue. Additionally, the breaking strength of the adhesive layer 12 is improved.

The significance of the polymer component (AX) in the case where the adhesive layer 12 contains the polymer component (AX) as one aspect of the polymer component (A) will be explained.

The polymer component (AX) contains structural units derived from a monomer having a nitrogen-containing functional group. It is believed that the nitrogen atom contained in the nitrogen-containing functional group exists as a polar group in the polymer component (AX). Due to the presence of this polar group (nitrogen-containing functional group), in the pressure-sensitive adhesive layer 12, the polymer components (AX) easily interact with each other through the nitrogen-containing functional group, forming a similar crosslinked structure in the pressure-sensitive adhesive layer 12. is thought to be formed.

As a result, even when the adhesive sheet 10 is heated, the cohesive force of the adhesive layer 12 is easily maintained, and as a result, when the adhesive sheet 10 is peeled from the adherend after the sealing process, the adhesive layer 12 is easily maintained. It is thought that it becomes more difficult for grass to remain. Moreover, since the cohesive force of the adhesive layer 12 becomes easier to maintain during heating, it is thought that the adhesive force during heating also increases. Additionally, the breaking strength of the adhesive layer also tends to increase.

Here, in one aspect of the present embodiment, the nitrogen-containing functional group in the polymer component (AX) does not contain an N-H bond for the following reason. Usually, when sealing a semiconductor element, an epoxy resin is often used as a sealing material. Epoxy resins easily react with groups having N-H bonds, such as amino groups. Therefore, when peeling the adhesive sheet from the adherend, the adhesive force between the adhesive layer and the adherend increases excessively, making it difficult to peel the adhesive sheet from the adherend, and to suppress glue remaining in the sealing material, N-H bonds are excluded from nitrogen-containing functional groups.

In one aspect of this embodiment, the pressure-sensitive adhesive layer 12 contains a polymer component (AX), and the polymer component (AX) contains a nitrogen-containing functional group. Therefore, the polarity of the entire pressure-sensitive adhesive layer increases, the compatibility between the copolymerization component (AX) and the energy ray-curable component increases, and mutual penetration of the three-dimensional network becomes easier. It is assumed that this suppresses the development of adhesion at high temperatures resulting from nitrogen-containing polar groups and the local generation of cured product (B), which may cause glue to remain on the adherend. Therefore, it is thought that it becomes easier to achieve both the adhesive strength of the adhesive layer 12 during heating and the prevention of glue remaining on the adherend.

In view of the above, according to the adhesive sheet 10 according to the present embodiment, the adhesive strength when heated is improved, and the occurrence of expansion and unintended peeling from the adherend during heating or a process involving heating and decompression is prevented. can be reduced, and, for example, the glue remaining on the adherend when the adhesive sheet 10 is peeled off after a process involving heating and reduced pressure can also be reduced.

In the present embodiment, the cured product (B), as described above, is an adhesive layer ( 12) is included. Therefore, in the components of the active energy ray-curable adhesive that are included simply for the purpose of reducing the adhesive force of the adhesive layer, such as in Patent Documents 1, 2, and 3, when the polymer component (A) or the polymer component (AX) is crosslinked In this embodiment, the crosslinking of the polymer component (A) or the polymer component (AX) progresses from the time of formation of the adhesive layer until the active energy ray-curable adhesive is cured at the time of use. The cured product (B) hardens before crosslinking of the polymer component (A) or polymer component (AX) proceeds. Therefore, the three-dimensional network of the polymer component (A) or the polymer component (AX) and the cured product (B) becomes prone to mutual invasion, which may cause localized cured product (B) to remain on the adherend. The above-described effect of suppressing the occurrence of is more easily obtained. Additionally, from the viewpoint that the energy-ray curable component has already been cured when the adhesive sheet is attached to the adherend, problems caused by decomposition of the polymerization initiator during the encapsulation process do not occur, and excess heat due to the uncured energy-ray curable component does not occur. There is an advantage that glue residue on the adherend is prevented due to the anchor effect.

The structure of the adhesive sheet 10 of this embodiment will be described. Hereinafter, description of symbols may be omitted.

(Adhesive layer)

·Polymer component (A)

The adhesive layer preferably contains a polymer component (A) in addition to the cured product (B).

The polymer component (AX) as one aspect of the polymer component (A) contains a structural unit derived from a monomer having a nitrogen-containing functional group. However, the nitrogen-containing functional group does not contain an N-H bond.

The polymer component (A) is a component formed by a polymerization reaction of a polymerizable compound. The polymer component (AX) is a polymerizable compound and is a component formed by polymerizing at least a monomer having a nitrogen-containing functional group. The polymerization reaction referred to here also includes polycondensation reaction.

In this specification, since the polymer component (AX) is an aspect included in the concept of the polymer component (A), even when simply referred to as the polymer component (A), the polymer component (AX) is not explicitly excluded. Unless otherwise specified, the polymer component (AX) is also included.

The polymer component (A), unlike the energy ray-curable component, is a component that has already been polymerized in the state of the raw materials for preparing the adhesive composition contained in the adhesive layer.

When the pressure-sensitive adhesive layer further contains a polymer component, a structure is formed in which the polymer component invades the three-dimensional network structure of the cured product of the energy ray-curable component, and the polymer component is in a crosslinked state by loose restraint of the network structure. This makes it easy to achieve both the adhesiveness of the adhesive layer and the cohesiveness of the adhesive layer.

·Type of polymer component (A)

The type of polymer component (A) is selected in consideration of the type of energy ray-curable component, the purpose of the adhesive layer, and the type of adherend to be adhered to the adhesive layer. Types of polymer component (A) include, for example, a group consisting of (meth)acrylic resin, polyester resin, polyurethane resin, acrylic urethane resin, silicone resin, rubber resin, phenoxy resin, and polystyrene resin. It is preferable that it is at least any compound selected from, and (meth)acrylic resin is more preferable. These polymer components (A) may be used individually, or may be used in combination of two or more types.

From the viewpoint of realizing a state in which the polymer component (A) is not directly bonded by reacting with the above-mentioned energy radiation curable component, but is loosely restrained by a structure that has invaded the three-dimensional network structure of the cured product (B), the adhesive layer As the polymer component (A), it is preferable to contain a non-energy ray curable polymer component that does not have energy ray curability. The content of the non-energy ray-curable polymer component is preferably 60% by mass or more, more preferably 75% by mass or more, and even more preferably 90% by mass or more of the total polymer component (A).

In the present embodiment, the mass ratio of the polymer component (A) to the total mass of the adhesive layer is 50 mass from the viewpoint of facilitating control of the adhesive strength when the adhesive sheet is heated and the cohesiveness of the adhesive layer. It is preferable that it is 90 mass% or less, and it is more preferable that it is 65 mass% or more and 85 mass% or less.

When the type of polymer component (A) is a (meth)acrylic resin, it is preferable that the polymer component (A) is a (meth)acrylic polymer. If the polymer component (A) is a (meth)acrylic polymer, compatibility with the energy ray-curable component is likely to increase, and control of the adhesive force of the adhesive layer, especially the adhesive force during heating, becomes easy.

However, when the polymer component (A) is a (meth)acrylic polymer, it is more preferable that the polymer component (A) is an acrylic polymer from the viewpoint of difficulty in thermal decomposition and difficulty in causing cohesive failure.

Hereinafter, the case where the polymer component (A) is a (meth)acrylic polymer will be described.

(meth)acrylic polymer is derived from (meth)acrylic acid alkyl ester (CH ₂ =CR ¹ COOR ² (R ¹ is hydrogen or methyl group, R ² is straight chain, branched chain or cyclic (alicyclic) alkyl group)) It is preferred that it contains polymer units that: It is preferable that part or all of the acrylic acid alkyl ester (CH ₂ =CR ¹ COOR ² ) is a (meth)acrylic acid alkyl ester in which the alkyl group R ² has 6 to 8 carbon atoms. Examples of (meth)acrylic acid alkyl esters in which the alkyl group R ² has 6 to 8 carbon atoms include n-hexyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, and n-octyl (meth)acrylate. Among these, it is preferable that R ² is a linear or branched alkyl group. Moreover, it is preferable that the carbon number of the alkyl group R ² is 8, from the viewpoint of improving the adhesiveness immediately after sticking the adhesive sheet to the adherend and improving the peelability from the adherend even after the adhesive sheet is heated. , 2-ethylhexyl (meth)acrylate is more preferable, and 2-ethylhexyl acrylate is still more preferable.

Examples of alkyl (meth)acrylate (CH ₂ =CR ¹ COOR ² ) in which the alkyl group R ² has 1 to 5 or 9 to 20 carbon atoms include methyl (meth)acrylate, ethyl (meth)acrylate, ( Propyl (meth)acrylate, n-butyl (meth)acrylate, n-pentyl (meth)acrylate, n-decyl (meth)acrylate, n-dodecyl (meth)acrylate, myristyl (meth)acrylate, palmy (meth)acrylate Til, and stearyl (meth)acrylate, etc. are mentioned.

(meth)acrylic acid alkyl ester may be used individually, or may be used in combination of two or more types.

In addition, “(meth)acrylic acid” in this specification is a notation used when indicating both “acrylic acid” and “methacrylic acid”, and the same applies to other similar terms.

From the viewpoint of difficulty in thermal decomposition and difficulty in causing cohesive failure, alkyl acrylate (i.e., CH ₂ = CR ¹ COOR ² and R ¹ is hydrogen) is preferably 80% by mass or more, and more preferably 90% by mass or more.

It is preferable that the mass ratio of the polymer unit derived from CH ₂ =CR ¹ COOR ² to the total mass of the (meth)acrylic polymer is 50% by mass or more.

The proportion of the mass of the polymer unit derived from the (meth)acrylic acid alkyl ester (above CH ₂ =CR ¹ COOR ² ) to the total mass of the (meth)acrylic polymer is preferably 50% by mass or more, and is 60% by mass or more. It is more preferable, and it is even more preferable that it is 80 mass % or more. The mass ratio of the polymer unit derived from the (meth)acrylic acid alkyl ester (CH ₂ =CR ¹ COOR ² ) is preferably 96% by mass or less from the viewpoint of improving initial adhesion.

In addition, in this embodiment, from the viewpoint of increasing the adhesiveness immediately after sticking the adhesive sheet to the adherend and improving the peelability from the adherend even after the adhesive sheet is heated, a (meth)acrylic polymer is used. It is preferable that the mass ratio of the polymer unit derived from 2-ethylhexyl (meth)acrylate to the total mass is 50% by mass or more. The mass ratio of the polymer unit derived from 2-ethylhexyl (meth)acrylate to the entire mass of the (meth)acrylic polymer is more preferably 60% by mass or more, and even more preferably 80% by mass or more. It is preferable that the mass ratio of the polymer unit derived from 2-ethylhexyl (meth)acrylate to the total mass of the (meth)acrylic polymer is 96% by mass or less.

When the (meth)acrylic polymer is a copolymer and the first copolymer unit in the (meth)acrylic copolymer is an alkyl (meth)acrylate ester, the copolymer other than the alkyl (meth)acrylate ester in the acrylic copolymer The type and number of polymer units (hereinafter referred to as “second copolymer units”) are not particularly limited. In this case, in the polymer component (AX), the “second copolymer unit” is a structural unit derived from a monomer having a nitrogen-containing functional group. On the other hand, for the polymer component (A) other than the polymer component (AX), for example, a functional group-containing monomer having a reactive functional group is preferable as the second copolymer unit. When using a cross-linking agent described later, the reactive functional group of the second copolymer unit is preferably a functional group capable of reacting with the cross-linking agent. Examples of this reactive functional group include carboxyl group, hydroxyl group, amino group, substituted amino group, and epoxy group.

The (meth)acrylic polymer in the polymer component (AX) is a copolymer, and the copolymer is derived from an alkyl (meth)acrylate ester (“first copolymer unit”) and a monomer having a nitrogen-containing functional group. When composed of a unit (“second copolymer unit”) and a copolymer unit other than the first copolymer unit and the second copolymer unit (hereinafter also referred to as the “third copolymer unit”), the third copolymer unit The type and number of are not particularly limited. For example, the third copolymer unit is preferably a functional group-containing monomer having a reactive functional group. When using a cross-linking agent described later, the reactive functional group of the third copolymer unit is preferably a functional group capable of reacting with the cross-linking agent. Examples of this reactive functional group include carboxyl group, hydroxyl group, and primary or secondary amino group. Among these, hydroxyl group is preferable as the reactive functional group. For the same reason that the above-mentioned nitrogen-containing functional group does not contain an N-H bond, it is preferable not to employ a functional group-containing monomer having a primary or secondary amino group as the functional group-containing monomer having a reactive functional group.

In this embodiment, from the viewpoint of extending the pot life of the raw material composition for forming the adhesive layer, it is preferable that the (meth)acrylic copolymer does not contain a copolymer unit derived from a monomer having a carboxyl group. Alternatively, the (meth)acrylic copolymer includes a copolymer unit derived from a monomer having a carboxyl group, and further comprises a copolymer unit derived from a monomer having a carboxyl group, which accounts for the mass of the entire (meth)acrylic copolymer. It is also preferable that the mass ratio is 1 mass% or less, and it is more preferable that it is 0.05 mass% or more and 1 mass% or less.

Monomers having a carboxyl group (hereinafter sometimes referred to as “carboxyl group-containing monomers”) include, for example, ethylenically unsaturated carboxyl such as acrylic acid, methacrylic acid, crotonic acid, maleic acid, itaconic acid, and citraconic acid. You can lift a mountain. When using a carboxyl group-containing monomer, (meth)acrylic acid is preferable and acrylic acid is more preferable from the viewpoint of reactivity and copolymerizability among carboxyl group-containing monomers. The carboxyl group-containing monomer may be used individually, or may be used in combination of two or more types.

In this embodiment, the (meth)acrylic copolymer preferably contains a copolymer unit derived from a monomer having a hydroxyl group.

When the (meth)acrylic copolymer contains a copolymer unit derived from a monomer having a hydroxyl group, the crosslinking density using the hydroxyl group as the crosslinking point can be increased when a crosslinking agent described later is used. As a result, the crosslinked structure of the (meth)acrylic copolymer can be effectively formed. From the viewpoint of enhancing this effect, it is preferable that the mass ratio of the copolymer unit derived from a monomer having a hydroxyl group to the total mass of the (meth)acrylic copolymer is 3% by mass or more. It is preferable that the mass ratio of the copolymer unit derived from a monomer having a hydroxyl group to the total mass of the (meth)acrylic copolymer is 9.9% by mass or less.

Monomers containing hydroxyl groups (hereinafter sometimes referred to as “hydroxyl group-containing monomers”) include, for example, 2-hydroxyethyl (meth)acrylic acid, 2-hydroxypropyl (meth)acrylic acid, and 3- (meth)acrylic acid. Hydroxypropyl, 2-hydroxybutyl (meth)acrylic acid, 3-hydroxybutyl (meth)acrylic acid, 4-hydroxybutyl (meth)acrylic acid, 2-hydroxy-3-phenoxypropyl (meth)acrylate, and hydroxyl-containing (meth)acrylic acid monomers such as 2-(meth)acryloyloxyethyl-2-hydroxyethyl-phthalic acid and hydroxyl-containing caprolactone-modified (meth)acrylate. Among hydroxyl group-containing monomers, 2-hydroxyethyl (meth)acrylate is preferable from the viewpoint of hydroxyl group reactivity and copolymerizability. Moreover, from the viewpoint of appropriately adjusting the adhesive strength so that the adhesive strength at room temperature does not become too high after heating, for example, 4-hydroxybutyl (meth)acrylate is preferable. Hydroxyl group-containing monomers may be used individually, or may be used in combination of two or more types.

Examples of acrylic acid esters having an epoxy group include glycidyl acrylate and glycidyl methacrylate.

The reactive functional group of the functional group-containing monomer having a reactive functional group is preferably bonded to the main chain of the polymer component (A) through three or more linearly bonded methylene groups. As a result, the probability of association between the reactive functional group and the cross-linking agent increases, and thus the cross-linking density increases. Additionally, the possibility that reactive functional groups remain after formation of the adhesive layer also decreases. As a result, the adhesive strength at room temperature after heating decreases, and it becomes easier to peel the adhesive sheet from the adherend. In addition, in the present invention, the methylene group does not include a methylidene group, and the methylene group may have one or more hydrogen atoms substituted. Additionally, the linear bond of the methylene group may be bonded indirectly through another group. For example, in the polymer component using 3-hydroxypropyl (meth)acrylate as the functional group-containing monomer, the hydroxy group as the reactive functional group is the main polymer component (A) through three linearly bonded methylene groups. joins the chain In addition, in the polymer component using 2-acryloyloxyethyl-2-hydroxyethyl-phthalic acid as the functional group-containing monomer, the hydroxy group as the reactive functional group is connected to the polymer component ( A) is bonded to the main chain, and these methylene groups are indirectly bonded to phthalic acid through an ester bond.

The reactive functional group of the functional group-containing monomer is preferably bonded to the main chain of the polymer component (A) through 10 or less linearly bonded methylene groups, and through 6 or less linearly bonded methylene groups. Therefore, it is more preferable to bind to the main chain of the polymer component (A).

In the polymer component (A) other than the polymer component (AX), the second copolymer component in the acrylic copolymer includes, in addition to the functional group-containing monomers described above, for example, an alkoxyalkyl group-containing (meth)acrylic acid ester and an aromatic ring. and copolymer units derived from at least any monomer selected from the group consisting of (meth)acrylic acid ester, vinyl acetate, and styrene.

·Monomer with nitrogen-containing functional group

The monomer having a nitrogen-containing functional group is not particularly limited as long as it is a polymerizable compound having a nitrogen-containing functional group, but is preferably an ethylenically unsaturated monomer having a nitrogen-containing functional group.

Nitrogen-containing functional groups include, for example, tertiary amino group (-NR ³ R ⁴ ), aminocarbonyl group (-(C=O)-NR ⁵ R ⁶ ), aminocarbonyloxy group (-O-(C=O )-NR ⁷ R ⁸ ), aminocarbonylamino group (-NR ⁹ -(C=O)-NR ¹⁰ R ^10A ), cyano group, nitro group, nitrogen-containing heterocyclic group, etc., and tertiary amino group. It is preferable that it is at least one selected from the group consisting of (-NR ³ R ⁴ ), aminocarbonyl group (-(C=O)-NR ⁵ R ⁶ ), cyano group, and nitrogen-containing heterocyclic group.

R ³ to R ¹⁰ and R ^10A each independently represent a substituent. The substituent includes, for example, a substituted or unsubstituted alkyl group with 1 to 6 carbon atoms (preferably 1 to 4 carbon atoms), and a substituted or unsubstituted alkyl group with 2 to 4 carbon atoms (preferably 2 to 3 carbon atoms). Alkenyl groups, etc. can be mentioned. The alkyl group may be straight chain, branched chain, or cyclic. The alkenyl group may be straight chain, branched chain, or cyclic. R ³ to R ¹⁰ and R ^10A are the same as or different from each other.

In this specification, the numerical range indicated using “~” means a range that includes the numerical value written before “~” as the lower limit and the numerical value written after “~” as the upper limit.

A nitrogen-containing heterocyclic group is a group obtained by removing one hydrogen atom from a nitrogen-containing heterocyclic compound. Nitrogen-containing heterocyclic compounds include, for example, morpholine, carbazole, pyrrolidone, piperidine, quinoline, pyrrolidine, aziridine, pyridine, pyrimidine, pyrazine, imidazole, and phthalimide. can be mentioned. The nitrogen-containing heterocyclic compound having the nitrogen-containing heterocyclic group is preferably morpholine from the viewpoint of increasing the cohesiveness of the adhesive layer.

The monomer (polymerizable compound) having a nitrogen-containing functional group may contain one or two or more of the nitrogen-containing functional groups listed above per molecule.

The monomer having a nitrogen-containing functional group is preferably at least one selected from the group consisting of heterocyclic vinyl compounds, (meth)acrylamide compounds, amino group-containing (meth)acrylic acid ester compounds, and (meth)acrylonitrile. It is more preferable that it is a cyclic vinyl compound. However, these compounds do not contain N-H bonds.

It is believed that the heterocyclic group contained in the heterocyclic vinyl compound is unlikely to decompose even if the adhesive sheet is heated due to its structure (ring structure).

Therefore, when the monomer having a nitrogen-containing functional group is a heterocyclic vinyl compound, the cohesive force of the adhesive layer is more likely to be maintained, and it is believed that the effect of the present embodiment is more expressed.

In this specification, (meth)acrylic means both acrylic and methacrylic. (meth)acrylonitrile means both acrylonitrile and methacrylonitrile.

The monomer having a nitrogen-containing functional group may be used individually, or may be used in combination of two or more types.

Heterocyclic vinyl compounds include, for example, N-acryloylmorpholine, N-methacryloylmorpholine, N-vinyl-2-pyrrolidone, N-acryloylpyrrolidone, and N-methacryl. Loylpyrrolidone, N-acryloylpiperidine, N-methacryloylpiperidine, N-acryloylpyrrolidine, N-methacryloylpyrrolidine, N-acryloylaziridine, N-meta Cryloyl aziridine, aziridinyl ethyl acrylate, aziridinyl ethyl methacrylate, 2-vinyl pyridine, 4-vinyl pyridine, 2-vinyl pyrazine, 1-vinylimidazole, N-vinylcarbazole, and N-vinyl phthalimide, etc. can be mentioned.

Among them, heterocyclic vinyl compounds include N-acryloylmorpholine, N-vinyl-2-pyrrolidone, N-acryloylpyrrolidone, and N-acrylic compounds from the viewpoint of expressing the effect of the present embodiment. Ilpiperidine, N-acryloylpyrrolidine, N-acryloylaziridine, aziridinyl ethyl acrylate, 2-vinylpyridine, 4-vinylpyridine, 2-vinylpyrazine, 1-vinylimidazole, N -Vinylcarbazole or N-vinylphthalimide is preferable, and N-acryloylmorpholine is more preferable.

Examples of the (meth)acrylamide compound include a compound represented by the following general formula (1).

[Formula 1]

In General Formula (1), R ¹¹ represents a hydrogen atom or a methyl group. R ¹² and R ¹³ are each independently a substituted or unsubstituted alkyl group with 1 to 6 carbon atoms (preferably 1 to 4 carbon atoms), or a substituted or unsubstituted alkyl group with 2 to 4 carbon atoms (preferably 2 to 3 carbon atoms) represents an alkenyl group. The alkyl group may be straight chain, branched chain, or cyclic. The alkenyl group may be straight chain, branched chain, or cyclic.

When R ¹² and R ¹³ have a substituent, the substituent is preferably each independently a dialkylamino group (-NR ¹⁴ R ¹⁵ ) or a hydroxyl group.

R ¹⁴ and R ¹⁵ each independently represent an unsubstituted alkyl group having 1 to 4 carbon atoms (preferably 1 to 3 carbon atoms).

(meth)acrylamide compounds include, for example, N,N-dimethylacrylamide, N,N-dimethylmethacrylamide, N,N-diethylacrylamide, N,N-diethylmethacrylamide, N ,N-di-n-propylacrylamide, N,N-di-n-propylmethacrylamide, N,N-di-isopropylacrylamide, N,N-di-isopropylmethacrylamide, N,N -Diallyl acrylamide, N,N-diallylmethacrylamide, N,N-di-n-butylacrylamide, N,N-di-n-butylmethacrylamide, N,N-ethylmethylacrylamide, and N,N-ethylmethylmethacrylamide.

Among them, (meth)acrylamide compounds include, from the viewpoint of expressing the effect of the present embodiment, N,N-dimethylacrylamide, N,N-diethylacrylamide, N,N-din-propylacrylamide, N,N-di-isopropylacrylamide, N,N-diallylacrylamide, N,N-di-n-butylacrylamide, or N,N-ethylmethylacrylamide are preferred, and N,N-dimethyl Acrylamide is more preferred.

Examples of amino group-containing (meth)acrylic acid ester compounds include compounds represented by the following general formula (2).

[Formula 2]

In general formula (2), R ¹⁶ represents a hydrogen atom or a methyl group. R ¹⁷ and R ¹⁸ each independently represent a substituted or unsubstituted alkyl group having 1 to 3 carbon atoms (preferably 1 to 2 carbon atoms). The alkyl group may be straight chain, branched chain, or cyclic (alicyclic). k is 1 or more and 4 or less, and is preferably 1 or more and 3 or less.

Examples of amino group-containing (meth)acrylic acid ester compounds include N,N-dimethylaminoethyl acrylate, N,N-dimethylaminoethyl methacrylate, N,N-diethylaminoethyl acrylate, N,N -diethylaminoethyl methacrylate, N,N-dimethylaminopropyl acrylate, and N,N-dimethylaminopropyl methacrylate.

Among them, amino group-containing (meth)acrylic acid ester compounds include N,N-dimethylaminoethyl acrylate, N,N-diethylaminoethyl acrylate, and N,N-dimethylaminoethyl acrylate, from the viewpoint of demonstrating the effect of the present embodiment. Dimethylaminopropylacrylate is preferred.

The proportion of the structural unit derived from a monomer having a nitrogen-containing functional group in the total mass of the polymer component (A) is preferably 1 mass% or more and 20 mass% or less from the viewpoint of expressing the effect of the present embodiment. A ratio, more preferably a ratio of 4.5 mass% or more and 18 mass% or less, and still more preferably a ratio of 9 mass% or more and 15 mass% or less.

If the ratio of structural units derived from monomers having a nitrogen-containing functional group is within this range, it becomes easier to adjust the adhesive strength of the adhesive sheet when heated and the cohesiveness of the adhesive layer.

When the acrylic copolymer contains a polymer component (AX), the third copolymerization component of the polymer component (AX) includes, for example, an alkoxyalkyl group-containing (meth)acrylic acid ester and an aromatic ring in addition to the functional group-containing monomer. and a copolymer unit derived from at least any monomer selected from the group consisting of (meth)acrylic acid ester, vinyl acetate, and styrene.

Examples of (meth)acrylic acid esters containing an alkoxyalkyl group include methoxymethyl (meth)acrylate, methoxyethyl (meth)acrylate, ethoxymethyl (meth)acrylate, and ethoxyethyl (meth)acrylate. You can.

Examples of (meth)acrylic acid esters having an aromatic ring include phenyl (meth)acrylate.

These monomers may be used individually or in combination of two or more types.

The weight average molecular weight (Mw) of the (meth)acrylic copolymer is preferably 50,000 to 2 million, more preferably 80,000 to 1 million, and even more preferably 100,000 to 400,000. If the weight average molecular weight Mw of the (meth)acrylic copolymer is 50,000 or more, it is easy to peel off the adhesive sheet without glue remaining on the adherend. The smaller the weight average molecular weight Mw of the (meth)acrylic copolymer, the lower the adhesive strength of the adhesive sheet to polyimide at 25°C (room temperature) after heat treatment at 190°C for 1.5 hours in a nitrogen atmosphere. there is.

The weight average molecular weight (Mw) of the (meth)acrylic copolymer is a standard polystyrene conversion value measured by Gel Permeation Chromatography (GPC) method, and is specifically obtained by measuring under the following conditions. will be.

(Measuring conditions)

·GPC device: manufactured by Tosoh Corporation, product name “HLC-8320”

·Measurement sample: Tetrahydrofuran solution with sample concentration of 1 mass%

Column: 2 “TSK gel Super HM-H” and 1 “TSK gel Super H2000” (all manufactured by Tosoh Corporation), connected in sequence

·Column temperature: 40℃

·Developing solvent: tetrahydrofuran

·Flow rate: 0.60 mL/min

The weight average molecular weight (Mw) of the polymer component (A) can also be measured by the same method as the weight average molecular weight (Mw) of the (meth)acrylic copolymer.

The (meth)acrylic copolymer can be produced according to a conventionally known method using the various raw material monomers described above.

The form of copolymerization of the (meth)acrylic copolymer is not particularly limited, and may be any of block copolymers, random copolymers, or graft copolymers.

In this embodiment, the mass ratio of the polymer component to the total mass of the adhesive layer 12 is preferably 50 mass% or more and 90 mass% or less, and more preferably 65 mass% or more and 85 mass% or less. .

In this embodiment, the mass ratio of the acrylic copolymer to the total mass of the adhesive layer 12 is preferably 50% by mass or more and 90% by mass or less, and more preferably 65% by mass or more and 85% by mass or less. do.

In this embodiment, the polymer component (A) is preferably crosslinked with a crosslinking agent.

It is believed that the cohesion of the adhesive layer is further maintained by the polymer component (A) being further crosslinked with a crosslinking agent. The reason for this is believed to be that the three-dimensional network structure formed from the polymer component (A) and the three-dimensional network structure of the cured product (B) form a mutually interpenetrating network structure.

In this embodiment, the crosslinking agent for the (meth)acrylic copolymer includes, for example, an isocyanate-based crosslinking agent, an epoxy-based crosslinking agent, an aziridine-based crosslinking agent, a metal chelate-based crosslinking agent, an amine-based crosslinking agent, and an amino resin-based crosslinking agent. there is. These crosslinking agents may be used individually, or may be used in combination of two or more types.

In this embodiment, from the viewpoint of improving the heat resistance and adhesive strength of the (meth)acrylic adhesive composition, a crosslinking agent (isocyanate-based crosslinking agent) that is a compound having an isocyanate group is preferable among these crosslinking agents. Isocyanate-based crosslinking agents include, for example, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, diphenylmethane-4, 4'-diisocyanate, diphenylmethane-2,4'-diisocyanate, 3-methyldiphenylmethane diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, Polyvalent isocyanate compounds such as dicyclohexylmethane-2,4'-diisocyanate and lysine isocyanate can be mentioned.

In addition, the polyvalent isocyanate compound may be a trimethylolpropane adduct type modified product of these compounds, a biuret type modified product reacted with water, or an isocyanurate type modified product having an isocyanurate ring.

In this embodiment, when the pressure-sensitive adhesive layer contains the polymer component (A) crosslinked by a crosslinking agent, the mixing ratio of the polymer component (A) and the crosslinking agent before crosslinking is preferably 0.1 part by mass with respect to 100 parts by mass. It is 20 parts by mass or less, more preferably 1 part by mass or more and 15 parts by mass or less, and even more preferably 5 parts by mass or more and 10 parts by mass or less.

Even when using a (meth)acrylic copolymer as the polymer component (A), the mixing ratio of the (meth)acrylic copolymer and the crosslinking agent before crosslinking is preferably 0.1 part by mass or more and 20 parts by mass or less, with respect to 100 parts by mass. More preferably, the ratio is 1 part by mass or more and 15 parts by mass or less, and even more preferably, the ratio is 5 parts by mass or more and 10 parts by mass or less.

It is preferable that the mixing ratio of the polymer component (A) and the crosslinking agent before crosslinking is within the above range because it is easy to improve the adhesive force of the adhesive sheet when heated.

In this embodiment, when the polymer component (A) is crosslinked with a crosslinking agent, the polymer component (A), a crosslinking agent, and a crosslinking accelerator may be mixed in the adhesive layer. It is desirable to select and use the crosslinking accelerator appropriately depending on the type of crosslinking agent, etc. For example, when crosslinking a (meth)acrylic copolymer with a polyisocyanate compound as a crosslinking agent, an organometallic compound-based crosslinking accelerator such as an organotin compound can be used.

The pressure-sensitive adhesive layer 12 also preferably contains a cross-linked product obtained by cross-linking the above-mentioned (meth)acrylic copolymer with a cross-linking agent.

·Hardened material (B)

The pressure-sensitive adhesive layer according to the present embodiment contains a cured product (cured product (B)) of an energy ray-curable component.

The energy ray curable component includes an energy ray curable compound. An energy ray curable compound is a compound that hardens when irradiated with an energy ray. The energy ray for curing the energy ray curable component is preferably at least one of ultraviolet rays (UV) and electron rays (EB), and more preferably ultraviolet rays.

There is no particular limitation on the energy ray curable compound according to the present embodiment, and it can be selected from conventionally known energy ray curable compounds. Energy-ray-curable compounds include energy-ray-curable monomers, low-molecular-weight compounds, oligomers, and resins. The energy ray curable component may be a composition containing at least one selected from the group consisting of an energy ray curable monomer, a low molecular weight compound, an oligomer, and a resin.

The energy ray curable component preferably contains at least one of a low molecular weight compound having a polymerizable functional group and an oligomer having a polymerizable functional group as an energy ray curable compound. When the energy ray-curable component is a low-molecular-weight compound or oligomer having a polymerizable functional group, the crosslinking density of the three-dimensional network structure in the cured product (B) increases. The pressure-sensitive adhesive layer contains a cured product (B) of an energy ray-curable component containing at least one of a low-molecular-weight compound having a polymerizable functional group and an oligomer having a polymerizable functional group, and a polymer component (A), thereby forming a polymer component (A). ) It becomes easy to invade the three-dimensional network structure of the cured product, and the effect of further improving the cohesion of the adhesive layer is more likely to be obtained.

The ratio of the low-molecular-weight compound having a polymerizable functional group is usually 3,000 or less, and is preferably 2,000 or less.

The theoretical molecular weight of the oligomer having a polymerizable functional group is usually 10,000 or less, and is preferably 8,000 or less.

Examples of the polymerizable functional group include a functional group having a polymerizable carbon-carbon double bond. The polymerizable functional group is preferably, for example, any group selected from the group consisting of (meth)acryloyl group, vinyl group, and allyl group.

From the viewpoint of improving the adhesive strength of the adhesive sheet to polyimide at 100°C, the number of polymerizable functional groups in the energy ray curable compound contained in the energy ray curable component is 2 to 6 per molecule. Preferred, more preferably 2 or more and 5 or less, further preferably 2 or more and 3 or less, and particularly preferably 2.

Since the energy ray curable component is a compound having two polymerizable functional groups in one molecule (bifunctional energy ray curable compound), the cohesion of the adhesive layer is improved and the crosslinking density is lower than that of the trifunctional or higher cured product (B). It is suppressed to a low level, and the followability of the adhesive layer to the minute irregularities on the surface of the adherend is improved.

In addition, the adhesive strength in the heating environment during the encapsulation process is easily improved, the flexibility of the adhesive is maintained, and it becomes easier to suppress the occurrence of glue residue. The heating environment in this embodiment is not particularly limited, but an example includes a sealing process.

When the adhesive strength in a high temperature environment is improved, when the adhesive sheet is placed in a high temperature and vacuum environment, blisters are generated at the interface between the adhesive sheet and the adherend due to the gas generated from the adhesive sheet itself or the member, and the adherend becomes adherent. It becomes easier to prevent peeling from the sheet. The high-temperature environment in this embodiment is not particularly limited, but an example is the encapsulation process of a semiconductor element, and after the encapsulation process, the adhesive sheet is attached to the surface of the encapsulant as a pretreatment for wiring. A process such as performing plasma processing is exemplified.

Additionally, by setting the number of polymerizable functional groups in one molecule to two or more, it becomes easier to form a three-dimensional network structure.

In one aspect of this embodiment, from the viewpoint of improving the adhesion to an adherend such as polyimide (in one aspect of this embodiment, the adhesion to polyimide in a high temperature or high temperature and reduced pressure environment is improved) From this point of view, it is preferable that the energy ray-curable compound is a compound having a polymerizable functional group and a cyclic structure. The polymerizable functional group is as described above. The cyclic structure is more preferably at least one cyclic structure selected from the group consisting of an aromatic ring, a heterocyclic ring, and an aliphatic ring. The energy ray-curable compound is also preferably a compound having at least any cyclic structure of an aromatic ring and an aliphatic ring.

The breaking strength per unit cross-sectional area of the adhesive layer containing the cured product (B) of the energy ray-curable compound is preferably 4.5 N/mm 2 or more, and more preferably 5.0 N/mm 2 or more. The method of measuring the breaking strength per unit cross-sectional area of the adhesive layer is as described in the Examples described later.

When the energy ray curable compound is a compound having two or more (preferably two) polymerizable functional groups in one molecule and also has a cyclic structure, an adhesive containing a cured product of the energy ray curable compound. The breaking strength per unit cross-sectional area of the layer is preferably 4.5 N/mm 2 or more, and more preferably 5.0 N/mm 2 or more. By increasing the breaking strength in this way, the effect of preventing glue residue can be further improved. For example, in a case where the adhesive layer contains a polymer component (AX) and the energy ray-curable compound in the cured product (B) is derived from a compound having a cyclic structure, the adhesive strength at 100°C is said to be increased. Even so, by increasing the breaking strength, the effect of preventing glue residue can be further improved.

In addition, in one aspect of the present embodiment, the energy ray curable compound is preferably a compound that does not have a cyclic structure and has a polymerizable functional group and a chain structure. In this case, it does not have a cyclic structure and has a chain structure. It is more preferable that it is a multifunctional energy ray-curable compound having a type structure.

In one aspect of this embodiment, a methylene group bonded in a straight chain is present between the first polymerizable functional group and the second polymerizable functional group, which are arbitrarily selected from two or more polymerizable functional groups possessed by the multifunctional energy ray-curable compound, The number of linearly bonded methylene groups present between the first polymerizable functional group and the second polymerizable functional group (hereinafter also referred to as “chain length between functional groups”) is preferably 4 or more, and more preferably 6 or more. do. When the number of linearly bonded methylene groups present between the first polymerizable functional group and the second polymerizable functional group is 4 or more, the Young's modulus of the pressure-sensitive adhesive layer decreases. As a result, even if the adhesive force at room temperature after heating is low, the initial adhesiveness after attaching the adhesive sheet to the adherend is maintained. A method of calculating the number of methylene groups bonded in a straight chain that exists between the first polymerizable functional group and the second polymerizable functional group will be explained using dipentaerythritol hexaacrylate as an example.

[Formula 3]

In the case of dipentaerythritol hexaacrylate, two polymerizable functional groups are selected, and methylene bonded in a straight chain exists between the first polymerizable functional group (acryloyl group) and the second polymerizable functional group (acryloyl group). The number of groups, defined as the maximum number, is 6. In cases where there are three or more polymerizable functional groups in the molecule, such as dipentaerythritol hexaacrylate, the maximum number of chain lengths between functional groups may be four or more. The chain length between functional groups is preferably 4 or more across all functional groups in the molecule. Additionally, in the case of dipentaerythritol hexaacrylate, in the linearly bonded methylene groups of 2 and 5 in the above structural formula, two hydrogen atoms are substituted with different groups. In addition, for example, in tripropylene glycol diacrylate, some of the methylene groups bonded in a straight chain have hydrogen atoms substituted with methyl groups, and these methylene groups are bonded indirectly through oxygen atoms.

In one aspect of this embodiment, a methylene group is present between the first polymerizable functional group and the second polymerizable functional group, which are arbitrarily selected from two or more polymerizable functional groups of the multifunctional energy ray-curable compound, and the first polymerizable functional group It is preferable that the number of linearly bonded methylene groups present between and the second polymerizable functional group is 8 or more and 30 or less, and more preferably 8 or more and 12 or less. When the number of linearly bonded methylene groups present between the first polymerizable functional group and the second polymerizable functional group is 8 or more and 30 or less, the effect of preventing glue residue is further improved, and the room temperature after heating is further improved. The effect of lowering the adhesive force is also obtained. In this case, when there are three or more polymerizable functional groups in the molecule of the multifunctional energy ray-curable compound, the maximum number of chain lengths between functional groups may be within the above range, and the chain length between functional groups may be within the range among all functional groups in the molecule. , it is preferable to be within the above range.

Examples of energy ray-curable low molecular weight compounds include polyfunctional (meth)acrylates. Energy-ray curable oligomers include polyfunctional urethane (meth)acrylate, polyfunctional polyester (meth)acrylate, polyfunctional polyether (meth)acrylate, and polyfunctional silicone (meth)acrylate. . These may be used individually by 1 type, or may be used in combination of 2 or more types. Polyfunctional means that two or more polymerizable functional groups are contained in one molecule.

Among polyfunctional (meth)acrylates, (meth)acrylates having two (meth)acryloyl groups in one molecule include 1,4-butanediol di(meth)acrylate and 1,6-hexanediol di( Meth)acrylate, tripropylene glycol diacrylate, 1,9-nonanediol diacrylate, 1,10-decanediol diacrylate, neopentyl glycol di(meth)acrylate, ethylene glycol di(meth)acrylate , Propylene glycol di(meth)acrylate, polypropylene glycol #400 diacrylate (product name: APG-400), polypropylene glycol #700 diacrylate (product name: APG-700), hexanediol di(meth)acrylate , tricyclodecane dimethanol di(meth)acrylate, 9,9-bis[4-(2-acryloyloxyethoxy)phenyl]fluorene, and propoxylated bisphenol A diacrylate. .

Among polyfunctional (meth)acrylates, (meth)acrylates having three (meth)acryloyl groups in one molecule include trimethylolethane tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, ε-caprolactone modified tris-(2-acryloxyethyl)isocyanurate, glycerol tri(meth)acrylate, etc. are mentioned.

Among polyfunctional (meth)acrylates, examples of (meth)acrylates having four (meth)acryloyl groups in one molecule include pentaerythritol tetra(meth)acrylate.

Among polyfunctional (meth)acrylates, examples of the (meth)acrylate having six (meth)acryloyl groups in one molecule include dipentaerythritol hexa(meth)acrylate.

As propoxylated bisphenol A diacrylate, for example, A-BPP (trade name) manufactured by Shinnakamura Chemical Co., Ltd. can be used. As ε-caprolactone modified tris-(2-acryloxyethyl)isocyanurate, for example, A-9300-1CL (trade name) manufactured by Shinnakamura Chemical Co., Ltd. can be used.

Polyfunctional (meth)acrylate may be used individually, or may be used in combination of two or more types.

Among polyfunctional (meth)acrylates, (meth)acrylates in which the number of (meth)acryloyl groups in one molecule is 2 to 5 are preferable, and (meth)acrylates in which the number of (meth)acryloyl groups is 2 or 3 are more preferable. , It is more preferable that it is a (meth)acrylate.

Additionally, the energy-ray curable low molecular weight compound is preferably (meth)acrylate having a cyclic structure, and more preferably (meth)acrylate having at least one of an aromatic ring and an aliphatic ring cyclic structure.

Additionally, the energy ray-curable low molecular weight compound is preferably a polyfunctional (meth)acrylate having a cyclic structure. In the polyfunctional (meth)acrylate having a cyclic structure, the number of (meth)acryloyl groups is preferably 2 to 5, more preferably 2 or 3, and still more preferably 2. In the polyfunctional (meth)acrylate having a cyclic structure, the cyclic structure is preferably at least one of an aromatic ring and an aliphatic ring.

When using ultraviolet rays as an energy ray to irradiate the energy ray curable component, it is preferable that the energy ray curable component further contains a photopolymerization initiator. By containing a photopolymerization initiator, the energy ray-curable component can be cured efficiently, and the polymerization curing time and the irradiation amount of active energy rays can be reduced.

Photopolymerization initiators include, for example, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin-n-butyl ether, benzoin isobutyl ether, acetophenone, and dimethylaminoacetophenone. , 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-hydroxycyclo Hexylphenylketone, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholino-propan-1-one, 4-(2-hydroxyethoxy)phenyl-2-(hydroxy- 2-propyl) ketone, benzophenone, p-phenylbenzophenone, 4,4'-diethylaminobenzophenone, dichlorobenzophenone, 2-methylanthraquinone, 2-ethylanthraquinone, 2-tertiary-butylanthraquinone , 2-aminoanthraquinone, 2-methylthioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyldimethyl ketal , acetophenone dimethyl ketal, p-dimethylaminobenzoic acid ester, oligo[2-hydroxy-2-methyl-1[4-(1-methylvinyl)phenyl]propanone], 2,4,6-trimethylbenzoyl-di Phenyl-phosphine oxide, and 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one, etc. I can hear it. These may be used individually or in combination of two or more types.

The photopolymerization initiator is preferably used in an amount ranging from 2 parts by mass to 15 parts by mass, more preferably from 5 parts by mass to 12 parts by mass, with respect to 100 parts by mass of the energy ray curable component.

The adhesive layer may contain other components as long as they do not impair the effects of the present invention. Other components that the adhesive layer may contain include, for example, an adhesion aid, an organic solvent, a flame retardant, a tackifier, an ultraviolet absorber, a light stabilizer, an antioxidant, an antistatic agent, a preservative, a fungicide, a plasticizer, an antifoamer, At least any component selected from the group consisting of colorants, fillers, wettability regulators, etc. can be mentioned.

In the present embodiment, the proportion of the cured product (B) in the total mass of the adhesive layer is preferably 5 mass% or more and 40 mass% or less, and is preferably a ratio of 10 mass% or more and 30 mass% or less. It is more preferable.

The thickness of the adhesive layer is appropriately determined depending on the purpose of the adhesive sheet. In this embodiment, the thickness of the adhesive layer is preferably 5 μm or more and 60 μm or less, and more preferably 10 μm or more and 50 μm or less. If the thickness of the adhesive layer is 5 μm or more, it becomes easy for the adhesive layer to follow the unevenness of the adherend, and generation of gaps can be prevented. The adherend having irregularities is not particularly limited, and examples include chip circuit surfaces. Therefore, for example, there is no risk that interlayer insulating material, encapsulating resin, etc. will enter the uneven gaps of the circuit surface of the semiconductor chip and clog the electrode pads for wiring connection on the chip circuit surface. If the thickness of the adhesive layer is 60 μm or less, it is difficult for the semiconductor chip to sink in the adhesive layer, and it is difficult for a step to occur between the semiconductor chip portion and the resin portion that seals the semiconductor chip. Therefore, there is no risk of the wiring being disconnected due to a step during rewiring.

Adhesion to polyimide at 100°C

The adhesive strength of the adhesive sheet to polyimide at 100°C is preferably 0.04 N/25 mm or more, more preferably 0.05 N/25 mm or more, and still more preferably 0.08 N/25 mm or more.

A pressure-sensitive adhesive sheet with an adhesive strength of 0.04 [N/25 mm] or more is a sheet that ensures adhesive strength when heated and shows good process suitability.

Therefore, by using an adhesive sheet of 0.04 [N/25 mm] or more, peeling of the adhesive sheet from an adherend such as a semiconductor element can be prevented. Additionally, displacement of the adherend from the position where it is attached to the adhesive sheet (misalignment) can also be suppressed. In addition, even when processing such as plasma treatment is performed at high temperature or in a high temperature and reduced pressure environment with the adhesive sheet attached to the semiconductor element encapsulated with an encapsulation resin, there is a gap between the adhesive sheet and the sealing body. It becomes difficult for swelling (blistering) or peeling from the bag to occur.

The adhesive strength of the adhesive sheet to polyimide at 100°C is preferably 1 N/25 mm or less, and more preferably 0.5 N/25 mm or less.

The adhesive strength of the adhesive sheet to polyimide at 25°C (room temperature) after heat treatment at 190°C for 1.5 hours in a nitrogen atmosphere is preferably 3 N/25 mm or less, and more preferably 2.5 N/25 mm or less. desirable. If the adhesive force is 3 N/25 mm or less, peeling and removal of the adhesive sheet after processing the electronic component becomes easy.

The Young's modulus of the adhesive layer is preferably 5 MPa or less, and more preferably 4 MPa or less. When the adhesive layer has such a Young's modulus, the adhesiveness when the adhesive sheet is attached to an electronic component is improved, and peeling of the adhesive sheet can be prevented until the start of subsequent processing.

It is preferable that the adhesive strength of the adhesive sheet to polyimide at 100°C is 0.06 N/25 mm or more, and that the breaking strength of the adhesive layer per unit cross-sectional area is 4.5 N/mm 2 or more. By satisfying such adhesion and breaking strength, the effect of preventing glue residue can be improved.

(write)

The base material is a member that supports the adhesive layer.

As a base material, for example, a sheet material such as a synthetic resin film can be used. Synthetic resin films include, for example, polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, and polyethylene naphthalate film. , polybutylene terephthalate film, polyurethane film, ethylene vinyl acetate copolymer film, ionomer resin film, ethylene/(meth)acrylic acid copolymer film, ethylene/(meth)acrylic acid ester copolymer film, polystyrene film, polycarbonate. Films, polyimide films, etc. can be mentioned. In addition, examples of the substrate include crosslinked films and laminated films.

The base material preferably contains a polyester resin, and is more preferably made of a material containing polyester resin as a main component. In this specification, a material containing a polyester resin as a main component means that the mass ratio of the polyester resin to the total mass of the material constituting the base material is 50% by mass or more. Examples of the polyester resin include any resin selected from the group consisting of polyethylene terephthalate resin, polybutylene terephthalate resin, polyethylene naphthalate resin, polybutylene naphthalate resin, and copolymer resins of these resins. It is preferable, and polyethylene terephthalate resin is more preferable.

As a base material, a polyethylene terephthalate film or a polyethylene naphthalate film is preferable, and a polyethylene terephthalate film is more preferable.

When curing the energy ray curable component by irradiating an energy ray from the substrate side, the substrate is preferably formed of a material that transmits the energy ray. When using ultraviolet rays as energy rays, the base material is preferably formed of a material that transmits ultraviolet rays.

The lower limit of the storage modulus of the substrate at 100°C is preferably 1 × 10 ⁷ Pa or more, and more preferably 1 × 10 ⁸ Pa or more, from the viewpoint of dimensional stability during processing. The upper limit of the storage modulus of the substrate at 100°C is preferably 1 × 10 ¹² Pa or less from the viewpoint of processing suitability.

In addition, in this specification, the storage elastic modulus of the base material at 100°C is the value of the tensile elastic modulus measured at a frequency of 1 Hz using a viscoelasticity measuring instrument. The substrate to be measured was cut into 5 mm in width and 20 mm in length, and the storage viscoelasticity at 100°C was measured using a viscoelasticity measuring device (DMAQ800, manufactured by TA Instruments) at a frequency of 1 Hz and in tension mode. do.

In order to increase the adhesion between the substrate and the adhesive layer, the first substrate surface may be subjected to at least any surface treatment such as primer treatment, corona treatment, or plasma treatment.

The thickness of the base material is preferably 10 μm or more and 500 μm or less, more preferably 15 μm or more and 300 μm or less, and still more preferably 20 μm or more and 250 μm or less.

(release sheet)

There is no particular limitation on the release sheet. For example, from the viewpoint of ease of handling, the release sheet preferably includes a release base material and a release agent layer formed by applying a release agent onto the release base material. Moreover, the release sheet may be provided with a release agent layer only on one side of the release substrate, or may be provided with a release agent layer on both sides of the release substrate.

When curing the energy ray curable component by irradiating an energy ray from the release sheet side after lamination of the release sheets, it is preferable that the release sheet is formed of a material that transmits the energy ray. When using ultraviolet rays as energy rays, the release sheet is preferably formed of a material that transmits ultraviolet rays.

Examples of the peelable substrate include a paper substrate, a laminated paper obtained by laminating a thermoplastic resin such as polyethylene to the paper substrate, and a plastic film. Examples of the paper substrate include glassine paper, coated paper, and cast coated paper. Plastic films include polyester films (e.g., polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate), and polyolefin films (e.g., polypropylene, polyethylene, etc.). .

Release agents include, for example, olefin-based resins, rubber-based elastomers (e.g., butadiene-based resins, isoprene-based resins, etc.), long-chain alkyl-based resins, alkyd-based resins, fluorine-based resins, and silicone-based resins. there is. When the adhesive layer is made of a silicone-based adhesive composition, the release agent is preferably a non-silicon-based release agent.

The thickness of the release sheet is not particularly limited. The thickness of the release sheet is usually 20 μm or more and 200 μm or less, and is preferably 25 μm or more and 150 μm or less.

The thickness of the release agent layer is not particularly limited. When forming a release agent layer by applying a solution containing a release agent, the thickness of the release agent layer is preferably 0.01 μm or more and 2.0 μm or less, and more preferably 0.03 μm or more and 1.0 μm or less.

When using a plastic film as a peeling base material, the thickness of the plastic film is preferably 3 μm or more and 50 μm or less, and more preferably 5 μm or more and 40 μm or less.

(Method for manufacturing adhesive sheet)

The manufacturing method of the adhesive sheet is not particularly limited.

When forming an adhesive layer by an application method, it is preferable to dilute the adhesive composition with an organic solvent to prepare a coating liquid (adhesive liquid for application).

The adhesive composition contains at least an energy ray curable component and a polymer component (A). The adhesive composition may further contain at least any component selected from the group consisting of a crosslinking agent, a crosslinking accelerator, and other components.

Examples of organic solvents include aromatic solvents, aliphatic solvents, ester solvents, ketone solvents, and alcohol solvents. Examples of aromatic solvents include benzene, toluene, and xylene. Examples of aliphatic solvents include normal hexane and normal heptane. Examples of the ester solvent include ethyl acetate and butyl acetate. Examples of ketone-based solvents include methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and cyclopentanone. Examples of alcohol-based solvents include isopropyl alcohol and methanol.

For example, an adhesive sheet is manufactured through the following processes.

First, the adhesive composition is applied on the first substrate side of the substrate to form a coating film. Next, this coating film is dried, and an energy ray is further irradiated to cure the energy ray curable component to form a cured product, thereby forming an adhesive layer. After that, a release sheet is attached to cover the adhesive layer.

As another method of manufacturing an adhesive sheet, it is manufactured through the following processes. First, the adhesive composition is applied on the release sheet to form a coating film. Next, the coating film is dried, and the first substrate side of the substrate is bonded to the coating film. Next, energy rays are irradiated to the coating film through the release sheet to cure the energy ray curable component to form a cured product, thereby forming an adhesive layer.

In another method of producing a pressure-sensitive adhesive sheet, a pressure-sensitive adhesive composition is applied onto the first substrate surface of the substrate to form a coating film. Next, this coating film is dried, and a release sheet is attached to this coating film to cover the coating film. Thereafter, an energy ray is irradiated from at least one of the base material side and the release sheet side to cure the energy ray curable component in the coating film to form a cured product, thereby forming the adhesive layer.

The method of applying the coating liquid is not particularly limited. Application methods include, for example, spin coat method, spray coat method, bar coat method, knife coat method, roll knife coat method, roll coat method, blade coat method, die coat method, and gravure coat method. there is.

In order to prevent organic solvents and low-boiling components from remaining in the adhesive layer, it is preferable to apply the coating liquid to the substrate or release sheet and then heat and dry the coating film.

When a crosslinking agent is blended in the adhesive composition, it is preferable to heat the coating film in order to advance the crosslinking reaction and improve cohesion. Irradiation of the energy ray may occur before or after heating to advance the crosslinking reaction, but it is preferable to irradiate the energy ray after heating. In addition, when the adhesive composition is heated to dry the coating film and promote the crosslinking reaction of the adhesive composition, all reactions of the functional groups involved in crosslinking are not completed by heating, and during the subsequent storage of the adhesive sheet, the remaining adhesive gradually remains. It is thought that the functional groups react and further crosslinking of the adhesive composition progresses. Therefore, after heating the coating film, a structure in which the polymer component (A) is restrained is formed in the three-dimensional network structure of the cured product (B) by irradiation with energy rays, and crosslinking of the polymer component (A) progresses, resulting in the cured product ( It is thought that a state is formed in which the crosslinked structures of B) and polymer component (A) invade each other.

(Use of adhesive sheet)

The adhesive sheet is used as an adhesive sheet for processing electronic components. Additionally, another use mode of the adhesive sheet includes one in which it is used to fix or protect electronic components. As an example of fixing or protecting electronic components, adhesive sheets are used to seal semiconductor elements. The adhesive sheet of this embodiment is used after the energy ray-curable component in the adhesive composition is cured to form a cured product.

When sealing a semiconductor element that is not mounted on a metal lead frame but is stuck on an adhesive sheet, it is preferable that an adhesive sheet is used. Specifically, the adhesive sheet is preferably used not to seal the semiconductor element mounted on a metal lead frame, but to seal the semiconductor element stuck to the adhesive layer. That is, it is preferable to use it with the semiconductor element directly attached to the adhesive sheet. The adhesive sheet of the present invention is unlikely to cause expansion (blistering) between the adhesive sheet and the encapsulant or peeling from the encapsulant, even when the process is carried out at a high temperature or in a high temperature and reduced pressure environment. Types for packaging semiconductor devices without using a metal lead frame include panel level package (PLP) and WLP.

The adhesive sheet includes a process of attaching a frame member with a plurality of openings to the adhesive sheet, a process of attaching a semiconductor chip to an adhesive layer exposed from the opening of the frame member, and a process of covering the semiconductor chip with an encapsulation resin; It is preferably used in a process that includes a step of heat curing the encapsulation resin.

In addition, the material of the encapsulation resin is not particularly limited, and may be a thermosetting resin or an energy ray curable resin that is cured with energy rays such as ultraviolet rays.

In the pressure-sensitive adhesive sheet of this embodiment, when the pressure-sensitive adhesive layer contains a polymer component (AX), the polymer component (AX) has a “nitrogen-containing functional group that does not contain an N-H bond,” so the material for the encapsulation resin is: Epoxy resin can be preferably used.

When the material of the encapsulating resin is an epoxy resin, when peeling the adhesive sheet from the adherend, reaction between the epoxy resin and groups having N-H bonds cannot occur, so the adhesive sheet can be peeled off from the adherend relatively easily. This also makes it easier to reduce glue residue on the adherend.

After the process of thermally curing the encapsulation resin, a processing process such as plasma treatment may be performed as a process carried out under a high temperature or a high temperature and reduced pressure environment.

Processes other than the process of thermally curing the encapsulation resin and the plasma treatment process, which are performed at high temperatures or in a high temperature and reduced pressure environment, include a process of sputtering metal, etc. on electronic components, and a process of cleaning electronic components with hot water, etc. etc. can be mentioned.

An intermediate layer may be formed between the base material and the adhesive layer. It is desirable to provide the middle layer with a function according to the desired purpose. Examples of the intermediate layer include an oligomer encapsulation layer, a primer layer, and an antistatic layer, which will be described later. For example, by forming an intermediate layer, at least one of the following can be improved: adhesion between the substrate and the adhesive layer, suppression of precipitation of oligomers on the substrate surface, and antistatic property.

Additionally, a functional layer may be formed on the surface of the base material on the side where the adhesive layer is not formed. Examples of the functional layer include an oligomer encapsulation layer and an antistatic layer described later. For example, by forming an intermediate layer, at least one of suppression of precipitation of oligomers on the surface of the substrate and antistatic properties can be improved.

＜Second Embodiment＞

The adhesive sheet according to the second embodiment differs from the adhesive sheet according to the first embodiment in that it includes an oligomer encapsulation layer between the substrate and the adhesive layer. Since it is the same as the first embodiment in other respects, the description is omitted or simplified. Hereinafter, description of symbols may be omitted.

(Oligomer encapsulation layer)

The oligomer encapsulation layer is formed between the substrate and the adhesive layer. The oligomer encapsulation layer is a layer for encapsulating oligomers originating from the substrate into the substrate. The oligomer encapsulation layer preferably prevents oligomers from entering the pressure-sensitive adhesive layer even under high temperature conditions of, for example, 180°C or higher and 200°C or lower.

Fig. 2 shows a cross-sectional view of the adhesive sheet 10A according to the second embodiment. The adhesive sheet 10A has an oligomer encapsulation layer 13.

The adhesive sheet (10A) has a base material (11), an oligomer sealing layer (13), and an adhesive layer (12) in this order. In the adhesive sheet 10A, the oligomer encapsulation layer 13 is laminated on the first substrate surface 11a.

The adhesive layer 12 contains a polymer component (A) and a cured product (B).

Since the adhesive sheet 10A of the second embodiment has an oligomer sealing layer 13 between the substrate 11 and the adhesive layer 12, even if the adhesive sheet 10A is heated, the oligomer remains in the adhesive layer 12. ) and the adherend can be prevented from moving to the interface.

Therefore, according to the adhesive sheet 10A of the second embodiment, the adhesive strength during heating can be further improved, and the residue of glue when peeled from the adherend can be further prevented.

·Film thickness of oligomer encapsulation layer

The thickness of the oligomer encapsulation layer is preferably 50 nm or more and 500 nm or less, and more preferably 80 nm or more and 300 nm or less.

If the thickness of the oligomer encapsulation layer is 50 nm or more, the oligomer contained in the substrate can be effectively prevented from entering the adhesive layer.

If the thickness of the oligomer encapsulation layer is 500 nm or less, it becomes easy to wind up the adhesive sheet, for example, around the core material in a roll shape. Materials of the core material include, for example, paper, plastic, and metal.

The material of the oligomer encapsulation layer is not particularly limited as long as it can prevent the oligomers in the base material from infiltrating the adhesive layer 12.

For example, the oligomer encapsulation layer is preferably a cured film obtained by curing the composition for the oligomer encapsulation layer. The composition for the oligomer encapsulation layer preferably contains at least one member selected from the group consisting of, for example, (A) an epoxy compound, (B) a polyester compound, and (C) a polyfunctional amino compound, and (A) It is more preferable that it contains an epoxy compound and (C) a polyfunctional amino compound, and it is still more preferable that it contains (A) an epoxy compound, (B) a polyester compound, and (C) a polyfunctional amino compound.

The composition for oligomer encapsulation layer may further contain (D) an acidic catalyst in order to promote the curing reaction.

·(A) Epoxy compound

(A) The epoxy compound is preferably a bisphenol A type epoxy compound. Examples of the bisphenol A type epoxy compound include bisphenol A diglycidyl ether.

·(B) Polyester compound

(B) The polyester compound is not particularly limited and can be appropriately selected from known polyester compounds. Polyester compounds include, specifically, an invertible polyester compound, which is a resin obtained by a condensation reaction of a polyhydric alcohol and a polybasic acid, and is a condensate of a dibasic acid and a dihydric alcohol, or a compound modified with a non-drying oil, fatty acid, etc., and and a convertible polyester compound that is a condensate of a dibasic acid and a trihydric or higher alcohol.

(B) As polyhydric alcohols and polybasic acids used as raw materials for the polyester compound, known polyhydric alcohols and polybasic acids can be appropriately selected and used.

·(C) Multifunctional amino compound

(C) As the polyfunctional amino compound, for example, melamine compounds, urea compounds, benzoguanamine compounds, and diamines can be used.

Examples of melamine compounds include hexamethoxymethylmelamine, methylated melamine compounds, and butylated melamine compounds.

Examples of urea compounds include methylated urea compounds and butylated urea compounds.

Examples of the benzoguanamine compound include methylated benzoguanamine compounds and butylated benzoguanamine compounds.

Examples of diamines include ethylenediamine, tetramethylenediamine, hexamethylenediamine, N,N'-diphenylethylenediamine, and p-xylylenediamine.

From the viewpoint of curability, hexamethoxymethylmelamine is preferable as the polyfunctional amino compound (C).

·(D) Acidic catalyst

Examples of the acidic catalyst (D) include hydrochloric acid and p-toluenesulfonic acid.

·Hardened film

In this embodiment, the oligomer encapsulation layer contains (A) a bisphenol A type epoxy compound, (B) a polyester compound, and (C) a polyfunctional amino compound in an amount of (A) 50% by mass or more and 80% by mass or less, respectively. , (B) 5 mass% or more and 30 mass% or less, and (C) 10 mass% or more and 40 mass% or less. (D) When blending the acidic catalyst into the composition for oligomer encapsulation layer, it is preferable that the content of component (D) is 1% by mass or more and 5% by mass or less.

According to the cured film obtained by curing the composition for the oligomer encapsulation layer with the mixing ratio in the above-mentioned range, the effect of preventing oligomers from entering the pressure-sensitive adhesive layer 12 by the oligomer encapsulation layer can be improved.

(Method for producing adhesive sheet of second embodiment)

The pressure-sensitive adhesive sheet of the second embodiment is manufactured through the following processes, for example.

First, the composition for forming an oligomer encapsulation layer is applied on the first substrate surface of the substrate to form a coating film. Next, this coating film is heated and cured to form a cured film that becomes the oligomer encapsulation layer. Conditions for heat curing are, for example, 120°C or higher and 170°C or lower, for 5 seconds or more and within 5 minutes.

Next, an adhesive layer is formed on the oligomer encapsulation layer formed on the first substrate surface of the substrate in the same manner as the description in the first embodiment.

＜Third Embodiment＞

The adhesive sheet according to the third embodiment differs from the adhesive sheet according to the second embodiment in that it has an oligomer encapsulation layer on both sides of the substrate. Since it is the same as the second embodiment in other respects, the description is omitted or simplified.

FIG. 3 shows a cross-sectional view of the adhesive sheet 10B according to an example of the third embodiment.

The adhesive sheet (10B) includes an oligomer encapsulation layer (13B) formed on the second substrate surface (11b) of the substrate (11), a substrate (11), and an oligomer formed on the first substrate surface (11a) of the substrate (11). It has the sealing layer 13A and the adhesive layer 12 in this order.

The pressure-sensitive adhesive sheet 10B of the third embodiment has oligomer encapsulation layers 13A, 13B on both sides of the substrate 11, and thus, in addition to the effect of the second embodiment, precipitation on the second substrate surface 11b It is possible to prevent oligomers from attaching to and contaminating members and devices other than the adherend. For example, when manufacturing a semiconductor device, contamination of the plate-shaped member in contact with the adhesive sheet during the heat press process can be suppressed.

(Method for producing adhesive sheet of third embodiment)

The adhesive sheet of the third embodiment is manufactured by forming a coating film made of the composition for forming an oligomer encapsulation layer on the first substrate surface and the second substrate surface of the substrate in the method for producing the adhesive sheet of the second embodiment. .

[Modification of embodiment]

The present invention is not limited to the above-described embodiments, and modifications and improvements within the range that can achieve the purpose of the present invention are included in the present invention. In addition, in the following description, if the members are the same as those described in the above embodiment, they are given the same reference numerals and their descriptions are omitted or simplified.

The adhesive sheet may be a sheet piece or may be provided in a state in which a plurality of adhesive sheets are laminated. In this case, for example, the adhesive layer may be covered with a base material of another adhesive sheet to be laminated.

Additionally, the adhesive sheet may be a strip-shaped sheet or may be provided in a rolled state. The adhesive sheet wound into a roll can be used by feeding it out from the roll and cutting it into a desired size. Additionally, the adhesive sheet may be cut in advance into a desired size and provided in a state supported on a strip-shaped release sheet.

Additionally, the oligomer encapsulation layer may be formed only on the second substrate surface of the substrate. An adhesive layer may be formed on the second substrate surface of the substrate directly or through an oligomer encapsulation layer or the like. The adhesive layer is used when attaching the adhesive sheet to a support substrate or the like and fixing electronic components on the adhesive layer of the adhesive sheet. The adhesive used in the adhesive layer may be of the same type as the adhesive of the adhesive layer, or may be of a different type.

Example

Hereinafter, the present invention will be described in more detail through examples. The present invention is not limited to these examples at all.

〔Assessment Methods〕

Evaluation of the adhesive sheet was performed according to the method shown below. The results are shown in Table 1, Table 2 and Table 3.

(Evaluation of blister generation during high temperature vacuum)

A glass epoxy substrate (manufactured by Hitachi Chemical Co., Ltd., “MCL-E-679FG” (brand name), 100 mm × 100 mm × 0.4 mm) was polished using an abrasive of #800. After polishing, the adhesive sheets produced in Examples and Comparative Examples were attached to the entire polished surface of the glass epoxy substrate. A roll laminator was used to attach the adhesive sheet.

After the adhesive sheet was attached to a glass epoxy substrate, it was vacuum laminated at 100°C using a heating vacuum laminator (manufactured by Nikko Materials Co., Ltd., “V130” (brand name)) to produce a measurement sample.

After vacuum lamination, the measurement sample was immersed in 85°C hot water for 30 minutes. After immersion, the measurement sample was taken out from the hot water, and water droplets on the surface of the measurement sample were wiped off. After wiping, the measurement sample was placed in a heated vacuum dryer at 25°C.

After that, the pressure inside the heating vacuum dryer was reduced (less than 0.005 MPa), and the measurement sample was heated at a set temperature of 130°C. The temperature increase rate was set to 5°C/min. When the heated vacuum dryer was heated from 25°C to 130°C, it was visually confirmed whether expansion (blistering) had occurred.

Judgment A: No swelling (blister) occurred.

Judgment B: Swelling (blister) occurred in less than 50% of the area of 10 cm2 of the adherend.

Judgment C: Expansion (blister) occurred in an area of 50% or more of 10 cm2 of the adherend.

(Initial adhesion test)

The surface of a glass epoxy substrate (manufactured by Hitachi Chemical Co., Ltd., “MCL-E-679FG” (brand name), 100 mm × 100 mm × 0.4 mm) was polished using an abrasive of #800. After polishing, the adhesive sheets produced in Examples and Comparative Examples were attached to the entire polished surface of the glass epoxy substrate. The attachment of the adhesive sheet was performed by reciprocating a 2 kg roll once. After standing for 30 minutes in a standard environment (23°C, 50%RH), the adhesive force was measured in the same standard environment.

The measurement conditions are as follows.

·Device: Tensile tester AG-X plus 10kN manufactured by Shimadzu Works

·Peeling angle: 180°

·Peeling speed: 300 mm/min

The case where this adhesive force was 0.08 N/25 mm or more was evaluated as A, and the case where it was less than 0.08 N/25 mm was evaluated as B.

(Adhesiveness to polyimide at 100°C)

A polyimide film (manufactured by Toray DuPont Co., Ltd., Kapton 200H (brand name)) is spread on an aluminum plate (150 mm 1 mm). For polyimide films, the adhesive force of the adhesive sheet was measured by changing the measurement temperature, referring to JIS Z 0237 (2000). The adhesive sheets prepared in the examples and comparative examples were attached to the polyimide film to prepare a measurement sample. This measurement sample was placed in an environment of 23°C and 50% relative humidity for 30 minutes, and then at 100°C for 3 minutes. After placing it in an environment, a tensile test was performed in an environment of 100°C.

Additionally, an adhesive sheet with an adhesive force of 0.04 [N/25 mm] or more is judged to be a sheet that has secured adhesive force and shows good process suitability.

The measurement conditions are as follows.

·Device: Tensile tester with constant temperature bath (“Tensilon” (product name) manufactured by Orientech Co., Ltd.)

·Peeling angle: 180°

·Peeling speed: 300 mm/min

In addition, in this specification, polyimide may be abbreviated as PI.

(Adhesiveness to polyimide at room temperature after heating)

Similarly to the adhesive strength to polyimide at 100°C, the adhesive sheets produced in Examples and Comparative Examples were affixed to the polyimide film to produce measurement samples. Thereafter, the measurement sample was heated in a nitrogen environment.

Heating conditions are as follows.

·Device: MS-3642 manufactured by MOTOYAMA

·N ₂ flow rate: 1.5 L/min (N ₂ purity: 99.995% (volume))

·Room temperature: 190℃

·Time: 1.5 hr

After that, after leaving it in a standard environment (23°C, 50%RH) for 6 hours or more, the adhesive sheet was peeled from the measurement sample in the same standard environment at a peeling angle of 180° and a peeling speed of 300 mm/min.

(Young’s modulus of adhesive layer)

In the examples and comparative examples, instead of bonding the dried coating film of the adhesive liquid to the substrate on which the oligomer encapsulation layer was formed, it was bonded to the side provided with the release agent layer of Lintec's release film "SP-PET381031" (brand name). , a single-layer adhesive layer without a substrate was produced. These four adhesive layers were laminated so that the sample had a thickness of 200 μm. A tensile test was performed under the following conditions using this laminate of only the adhesive layer as a sample, and from the measurement results of strain and stress, the change in stress with respect to the change in strain was graphed. From the initial slope of the change in stress with respect to the change in strain, the Young's modulus of the adhesive was measured.

·Device: Tensile tester AG-X plus 10kN manufactured by Shimadzu Works

·Test sample size: measurement area length 50 mm × 15 mm width

·Tensile test speed: 200 mm/min

(Breaking strength per unit cross-sectional area of the adhesive layer)

A tensile test was performed in the same manner as the Young's modulus measurement of the adhesive layer, and the maximum value of the force at fracture (breaking strength) was divided by the cross-sectional area of the initial sample to calculate the breaking strength per unit area.

(First Residue Evaluation (First Pool Residual Evaluation))

The copper foil was previously polished with an abrasive of #800, and polishing scratches were formed along one direction of the surface of the copper foil (arithmetic average roughness Ra after polishing = 0.2 ± 0.1 μm). The adhesive sheets produced in Examples and Comparative Examples were affixed to the surface of the copper foil on which the polishing scratches were formed. Here, only the adhesive sheet of Comparative Example 1-3 was irradiated with ultraviolet rays using a high-pressure mercury lamp manufactured by iGraphics as an ultraviolet irradiation device under the conditions of an illuminance of 200 mW/cm2 and an accumulated light amount of 200 mJ/cm2. After that, the adhesive sheet stuck to the copper foil was heated at 100°C for 30 minutes, then heated at 180°C for 30 minutes, and then heated at 190°C for 60 minutes. After heating, the adhesive sheet was peeled off at a rate of 3 mm/min at room temperature. The direction in which the adhesive sheet was peeled was set to be perpendicular to the polishing scratches. The surface of the copper foil after peeling off the adhesive sheet was observed with a digital microscope, and the glue residue was evaluated. The judgment criteria in evaluating the remaining grass are as follows.

Judgment A: No grass remained.

Judgment B: Partial fullness remained.

C judgment: Grass remained on the entire surface.

(Second Residue Assessment (Second Pool Residual Assessment))

Using a polyimide film (Kapton 200H (product name), manufactured by Toray DuPont Co., Ltd.), double-sided tape (TL-450S-16 (brand name), manufactured by Lintech Co., Ltd.), a silicon mirror wafer (6 inches in diameter, thick) is used. It was bonded to a mirror surface of 0.68 mm).

Thereafter, circular marks of 200 μm phi were engraved at 3 mm intervals using a laser marker (CSM300M manufactured by EO TECHNICS) on the surface of the polyimide film (laser wavelength 512 nm, output 1.0 W, scanning speed 300 mm). /s).

In addition, in order to evaluate under conditions in which glue residue is likely to occur during this evaluation, the above-mentioned mark was imprinted on the surface of the polyimide film by laser ablation as described above to form irregularities.

Referring to JIS Z0237 (2000), the adhesive sheets produced in Examples and Comparative Examples were laminated on the processed surface of the polyimide film by applying force using the dead weight of a 2 kg roller, and then heated and laminated from thereon to obtain a measurement sample. produced.

The conditions for heating laminate are as follows.

·Device: Vacuum laminator V-130 manufactured by Nikko Materials Co., Ltd.

·Heating temperature: 100℃

·Vacuum standby: 60 sec

·Diaphragm pressurization: 0.3 MPa

Thereafter, the measurement sample was heated in a nitrogen environment.

Heating conditions are as follows.

·Device: MS-3642 manufactured by MOTOYAMA

·N ₂ flow rate: 1.5 L/min (N ₂ purity: 99.995% (volume))

·Room temperature: 190℃

·Time: 1.5 hr

After that, after leaving it in a standard environment (23°C, 50%RH) for 6 hours or more, the adhesive sheet was peeled from the measurement sample at a peeling angle of 180° and a peeling speed of 300 mm/min. The surface of the polyimide film after peeling off the adhesive sheet was observed with a SEM (scanning electron microscope, observation magnification 3000 times), and the residue generation was evaluated for glue remaining. The judgment criteria in evaluating the remaining grass are as follows.

-Criteria-

Judgment A: There was no residue.

Judgment B: There was residue, and the size of the residue was less than 5 ㎛.

Judgment C: There was residue, and the size of the residue was 5 ㎛ or more and less than 10 ㎛.

D Judgment: There was residue, and the size of the residue was 10 ㎛ or more.

[Production of adhesive sheet]

[Example 1-1]

(1-1) Preparation of oligomer encapsulation liquid for application

The following (A) bisphenol A type epoxy compound, (B) polyester compound, (C) polyfunctional amino compound, and (D) acid catalyst were mixed and stirred sufficiently to obtain an oligomer encapsulant solution for application according to Example 1-1. (Composition for oligomer encapsulation layer) was prepared.

(A) Bisphenol A type epoxy compound

“EPICLON H-360” (brand name) manufactured by DIC, solid content concentration: 40% by mass, mass average molecular weight: 25000

(B) Polyester compound

“Bylon GK680” (brand name) manufactured by Toyo Spun Yarn, number average molecular weight: 6000, glass transition temperature: 10°C

(C) Multifunctional amino compound

Hexamethoxymethylmelamine, “Cymel 303” manufactured by Nippon Scitech Industries (brand name)

(D) acid catalyst

Methanol solution of p-toluenesulfonic acid (solid concentration: 50% by mass)

Specifically, 100 parts by mass of the bisphenol A type epoxy compound (A), 19.0 parts by mass of a toluene diluted solution (solid content concentration: 30 mass%) of the polyester compound (B), and hexamethoxymethyl (C) 11.4 parts by mass of melamine were added and further diluted with a mixed solvent of toluene/methyl ethyl ketone = 50 mass%/50 mass% to prepare a solution with a solid content concentration of 3 mass%. The prepared solution was stirred, and 2.9 parts by mass of a methanol solution of (D) p-toluenesulfonic acid (solid content concentration: 50% by mass) was added to the stirred solution to obtain an oligomer encapsulating agent solution for application. In addition, all parts by mass are converted to solid content.

(1-2) Production of oligomer encapsulation layer (production of substrate with oligomer encapsulation layer formed)

The prepared oligomer encapsulant solution for application was evenly spread on one side of an annealed biaxially stretched polyethylene terephthalate film (“Teijin Tetron G2A” (product name) manufactured by Teijin Film Solutions Co., Ltd., thickness 25 ㎛) using the Meyer bar coat method. applied. The applied film was passed through the inside of an oven, the coating film was cured by heating, and an oligomer encapsulation layer with a thickness of 150 nm was formed, thereby obtaining a base material with the oligomer encapsulation layer formed thereon. The conditions for blowing out hot air in the oven were that the temperature was 150°C and the wind speed was 8 m/min. The processing speed in the oven was adjusted to the speed at which the applied film passes through the inside of the oven in 20 seconds.

(1-3) Preparation of adhesive composition

The following materials (polymer (polymer component), crosslinking agent, low molecular weight compound having a polymerizable functional group, photopolymerization initiator, and diluting solvent) were mixed and sufficiently stirred to prepare an adhesive liquid for application according to Example 1-1.

·Polymer: Acrylic acid ester copolymer, 100 parts by mass (solid content)

The acrylic acid ester copolymer was prepared by copolymerizing 92.8 mass% of 2-ethylhexyl acrylate, 7.0 mass% of 2-hydroxyethyl acrylate, and 0.2 mass% of acrylic acid.

- Crosslinking agent: Aliphatic isocyanate containing hexamethylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd.; [Coronate HX], 7.4 parts by mass (solid content)

- Low molecular weight compound having a polymerizable functional group: Tricyclodecane dimethanol diacrylate [manufactured by Shinnakamura Chemical Co., Ltd.; A-DCP] 23.3 parts by mass (solid content)

Photopolymerization initiator: 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one [IGM Resin company] manufacturing ; Omnirad 127〕4.1 parts by mass (solid content)

· Diluting solvent: Ethyl acetate was used, and the solid content concentration of the adhesive liquid for application was adjusted to 30% by mass.

(1-4) Production of adhesive layer

The prepared pressure-sensitive adhesive liquid for application was used using a knife coater to form a release film (manufactured by Lintech Co., Ltd.) made of a 38-μm-thick transparent polyethylene terephthalate film provided with a silicone-based release layer; SP-PET382150] was applied to the peeled layer side. Next, the coating film of the adhesive liquid for application on the release film was heated at 90°C for 90 seconds, and then heated at 115°C for 90 seconds to dry the coating film. After that, the coating film and the surface on which the oligomer encapsulation layer was formed of the base material on which the oligomer encapsulation layer was formed obtained by the above-mentioned procedure were bonded together. Then, the coating film was irradiated with ultraviolet rays from the release film side under the conditions of an illuminance of 200 mW/cm2 and an accumulated light amount of 200 mJ/cm2 using a high-pressure mercury lamp manufactured by iGraphics as an ultraviolet irradiation device, and a 50-μm-thick film was formed. An adhesive layer was produced. In this way, the adhesive sheet according to Example 1-1 was obtained.

[Example 1-2]

Instead of 23.3 parts by mass (solid content) of tricyclodecane dimethanol diacrylate, 9,9-bis[4-(2-acryloyloxyethoxy)phenyl]fluorene [manufactured by Shinnakamura Chemical Co., Ltd.; A-BPEF] The adhesive sheet of Example 1-2 was obtained in the same manner as Example 1-1, except that 23.3 parts by mass (solid content) was used.

[Example 1-3]

Instead of 23.3 parts by mass (solid content) of tricyclodecane dimethanol diacrylate, propoxylated bisphenol A diacrylate [manufactured by Shinnakamura Chemical Co., Ltd.; [A-BPP] The pressure-sensitive adhesive sheet of Example 1-3 was obtained in the same manner as Example 1-1, except that 23.3 parts by mass (solid content) was used.

[Example 1-4]

Instead of 23.3 parts by mass (solid content) of tricyclodecane dimethanol diacrylate, dipentaerythritol hexaacrylate [manufactured by Shinnakamura Chemical Co., Ltd.; [A-DPH] (Chain length between functional groups: 6) The adhesive sheet of Example 1-4 was obtained in the same manner as Example 1-1, except that 23.3 parts by mass (solid content) was used.

[Example 1-5]

Instead of 23.3 parts by mass (solid content) of tricyclodecane dimethanol diacrylate, ε-caprolactone modified tris(2-acryloxyethyl)isocyanurate [manufactured by Shinnakamura Chemical Co., Ltd.; A-9300-1CL] The adhesive sheet of Example 1-5 was obtained in the same manner as Example 1-1, except that 23.3 parts by mass (solid content) was used.

[Comparative Example 1-1]

In the production of the adhesive composition, the following materials (polymer, adhesive auxiliary, crosslinking agent, and diluting solvent) were mixed, and the process of irradiating ultraviolet rays was omitted in the production of the adhesive layer, the same as Example 1-1. Thus, the adhesive sheet of Comparative Example 1-1 was obtained.

·Polymer: Acrylic acid ester copolymer, 100 parts by mass (solid content)

The acrylic acid ester copolymer was prepared by copolymerizing 92.8 mass% of 2-ethylhexyl acrylate, 7.0 mass% of 2-hydroxyethyl acrylate, and 0.2 mass% of acrylic acid.

· Adhesion aid: Polybutadiene with hydroxyl groups at both ends [manufactured by Nippon Soda Co., Ltd.; GI-1000], 12.5 parts by mass (solid content)

- Crosslinking agent: Aliphatic isocyanate containing hexamethylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd.; [Coronate HX], 8.75 parts by mass (solid content)

· Dilution solvent: methyl ethyl ketone was used, and the solid content concentration of the adhesive liquid for application was adjusted to 30% by mass.

[Comparative Example 1-2]

In the production of the adhesive composition, the adhesive sheet of Comparative Example 1-2 was obtained in the same manner as in Comparative Example 1-1, except that no adhesive auxiliary agent was added.

[Comparative Example 1-3]

The pressure-sensitive adhesive sheet of Comparative Example 1-3 was obtained in the same manner as Example 1-1, except that the step of irradiating ultraviolet rays was omitted. In addition, in the first residue evaluation, the evaluation was performed after irradiation with ultraviolet rays under the conditions described above.

[Test/Evaluation Results]

As a result of the blister test, no expansion (blister) occurred for Examples 1-1, 1-2, and 1-3, so it was judged A, and for Examples 1-4 and 1-5, it was judged B, and comparison For Examples 1-1 and 1-2, it was a C decision, and for Comparative Example 1-3, it was a B decision. By curing the ultraviolet curable component in advance to form a cured product before sticking it to an adherend, the adhesive layer containing the cured product had improved adhesion, and the effect of suppressing the generation of blisters was recognized. Examples 1-1, 1-2, and 1-3 using an ultraviolet curable component having two polymerizable functional groups in one molecule have a higher effect of suppressing swelling (blistering).

As a result of the first residue evaluation, it was an A judgment of no glue residue for Examples 1-1, 1-2, 1-3, 1-4, and 1-5. For Comparative Example 1-1, it was judged B because some glue remained, and for Comparative Examples 1-2 and 1-3, it was judged C because glue remained on the entire surface.

From these results, even when the adhesive sheets related to Examples 1-1, 1-2, 1-3, 1-4 and 1-5 were used in the encapsulation process, no glue remained, and also Examples 1-1 and 1- It was confirmed that the adhesive sheets related to 2 and 1-3 were unlikely to peel even in processes in which blisters are likely to occur, such as plasma processes.

[Example 2-1]

(2-1) Preparation of oligomer encapsulation liquid for application

The oligomer encapsulating agent solution for application according to Example 2-1 was prepared in the same manner as the preparation of the oligomer encapsulating agent solution for application according to Example 1-1.

(2-2) Production of oligomer encapsulation layer (production of substrate with oligomer encapsulation layer formed)

As a substrate, an annealed biaxially stretched polyethylene terephthalate film (“Teijin Tetron G2A” (brand name), manufactured by Teijin Film Solutions Co., Ltd., thickness 25 μm) was prepared. Hereinafter, the annealed biaxially stretched polyethylene terephthalate film is also simply referred to as “PET film.”

The prepared oligomer encapsulant solution for application was uniformly applied to one side of the “PET film” by the Meyer bar coat method. The "PET film" after applying the oligomer encapsulating agent solution was passed through the inside of an oven, and the coating film was cured by heating to form an oligomer encapsulating layer with a thickness of 150 nm on one side of the PET film. Next, an oligomer encapsulation layer with a thickness of 150 nm was formed in the same manner on the other surface of the “PET film”, and a base material with a double-sided oligomer encapsulation layer was obtained. The conditions for blowing out hot air in the oven were that the temperature was 150°C and the wind speed was 8 m/min. The processing speed in the oven was adjusted to the speed at which the “PET film” after application passes through the inside of the oven in 20 seconds.

(2-3) Preparation of adhesive composition

The following materials (polymer (polymer component (A)), crosslinking agent, low-molecular-weight compound having a polymerizable functional group, photopolymerization initiator, and diluting solvent) were mixed and stirred sufficiently to obtain an adhesive solution for application according to Example 2-1. It was prepared.

·Polymer: Acrylic acid ester copolymer (polymer component (A)), 100 parts by mass (solid content)

The acrylic acid ester copolymer contains 80.8 mass% of 2-ethylhexyl acrylate, 12.0 mass% of acryloylmorpholine (a monomer having a nitrogen-containing functional group), 7.0 mass% of 2-hydroxyethyl acrylate, and 0.2 mass% of acrylic acid. By copolymerization, a polymer with a weight average molecular weight of 440,000 was prepared.

- Crosslinking agent: Aliphatic isocyanate containing hexamethylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd.; [Coronate HX], 7.4 parts by mass (solid content)

- Low molecular weight compound having a polymerizable functional group: propoxylated bisphenol A diacrylate [manufactured by Shinnakamura Chemical Co., Ltd.; A-BPP-3] 23.3 parts by mass (solid content)

Photopolymerization initiator: 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one [IGM Resin company] manufacturing ; Omnirad 127〕4.1 parts by mass (solid content)

· Diluting solvent: Ethyl acetate was used, and the solid content concentration of the adhesive liquid for application was adjusted to 30% by mass.

(2-4) Production of adhesive layer

The prepared pressure-sensitive adhesive liquid for application was used using a knife coater to form a release film (manufactured by Lintech Co., Ltd.) made of a 38-μm-thick transparent polyethylene terephthalate film provided with a silicone-based release layer; SP-PET382150] was applied to the peeled layer side. Next, the coating film of the adhesive liquid for application on the release film was heated at 90°C for 90 seconds, and then heated at 115°C for 90 seconds to dry the coating film. After that, the coating film and one side on which the oligomer encapsulation layer was formed were bonded to the base material on which the oligomer encapsulation layer was formed, which was obtained by the above-mentioned procedure. Then, the coating film was irradiated with ultraviolet rays from the release film side under the conditions of an illuminance of 200 mW/cm2 and an accumulated light amount of 200 mJ/cm2 using a high-pressure mercury lamp manufactured by iGraphics as an ultraviolet irradiation device, and a 50-μm-thick film was formed. An adhesive layer was produced. In this way, the adhesive sheet according to Example 2-1 was obtained.

[Example 2-2]

The acrylic acid ester copolymer as the polymer component (A) is copolymerized with 86.8 mass% of 2-ethylhexyl acrylate, 6.0 mass% of acryloylmorpholine, 7.0 mass% of 2-hydroxyethyl acrylate, and 0.2 mass% of acrylic acid. The pressure-sensitive adhesive sheet of Example 2-2 was obtained in the same manner as Example 2-1, except that a polymer with a weight average molecular weight of 510,000 was prepared.

[Example 2-3]

The acrylic acid ester copolymer as the polymer component (A) is copolymerized with 89.8 mass% of 2-ethylhexyl acrylate, 3.0 mass% of acryloylmorpholine, 7.0 mass% of 2-hydroxyethyl acrylate, and 0.2 mass% of acrylic acid. The pressure-sensitive adhesive sheet of Example 2-3 was obtained in the same manner as Example 2-1, except that a polymer with a weight average molecular weight of 520,000 was prepared.

[Example 2-4]

The acrylic acid ester copolymer as the polymer component (A) is comprised of 80.8 mass% of 2-ethylhexyl acrylate, 12.0 mass% of N,N-dimethylacrylamide (monomer having a nitrogen-containing functional group) as a monomer having a nitrogen-containing functional group, and acrylic acid. An adhesive sheet of Example 2-4 was obtained in the same manner as Example 2-1, except that 7.0% by mass of 2-hydroxyethyl and 0.2% by mass of acrylic acid were copolymerized to prepare a polymer with a weight average molecular weight of 500,000.

[Example 2-5]

Example 2- Except that the acrylic acid ester copolymer was prepared by copolymerizing 92.8 mass% of 2-ethylhexyl acrylate, 7.0 mass% of 2-hydroxyethyl acrylate, and 0.2 mass% of acrylic acid to prepare a polymer with a weight average molecular weight of 1,050,000. In the same manner as in 1, the adhesive sheet of Example 2-5 was obtained. In addition, the acrylic acid ester copolymer itself is the same as the acrylic acid ester copolymer related to Example 1-3.

[Comparative Example 2-2]

In the production of the adhesive composition, the following materials (polymer, adhesive auxiliary agent, crosslinking agent, and diluting solvent) were mixed, and the process of irradiating ultraviolet rays was omitted in the production of the adhesive layer, the same as Example 2-1. Thus, the adhesive sheet of Comparative Example 2-2 was obtained.

·Polymer: Acrylic acid ester copolymer, 100 parts by mass (solid content)

The acrylic acid ester copolymer was prepared by copolymerizing 92.8 mass% of 2-ethylhexyl acrylate, 7.0 mass% of 2-hydroxyethyl acrylate, and 0.2 mass% of acrylic acid to prepare a polymer with a weight average molecular weight of 1,050,000.

· Adhesion aid: Polybutadiene with hydroxyl groups at both ends [manufactured by Nippon Soda Co., Ltd.; GI-1000], 12.5 parts by mass (solid content)

- Crosslinking agent: Aliphatic isocyanate containing hexamethylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd.; [Coronate HX], 8.75 parts by mass (solid content)

· Dilution solvent: methyl ethyl ketone was used, and the solid content concentration of the adhesive liquid for application was adjusted to 30% by mass.

In addition, the acrylic acid ester copolymer itself is the same as the acrylic acid ester copolymer related to Comparative Example 1-1.

(Explanation in Table 2)

· “ACMO” means acryloylmorpholine.

· “DMAA” means N,N-dimethylacrylamide.

· “PI” means polyimide.

[Evaluation results]

The adhesive sheets of Examples 2-1, 2-2, 2-3, and 2-4 had good second residue evaluations compared to the adhesive sheet of Comparative Example 2-2.

In addition, in the adhesive sheet of Example 2-5, the composition of the adhesive layer itself is the same as that of Example 1-3, so Comparative Example 2-2 (the composition of the adhesive layer itself is the same as Comparative Example 1-1) Compared to , as shown in Table 1, the first residue evaluation was good, but in the second residue evaluation, all judgments were D.

The adhesive sheets of Examples 2-1, 2-2, 2-3, and 2-4 had adhesive strength to polyimide at 100°C of 0.04 [N/25 mm] or more. That is, the adhesive sheets of Examples 2-1, 2-2, 2-3, and 2-4 were sheets that had secured adhesive strength and showed good process suitability.

According to the pressure-sensitive adhesive sheet of this example, the pressure-sensitive adhesive layer contains the polymer component (A) and the cured product (B), thereby improving the adhesive strength during heating and preventing glue residue when peeled from the adherend. .

[Production of adhesive sheet]

[Example 3-1]

(3-1) Preparation of oligomer encapsulation liquid for application

The oligomer encapsulating agent solution for application according to Example 3-1 was prepared in the same manner as the preparation of the oligomer encapsulating agent solution for application according to Example 1-1.

(3-2) Production of oligomer encapsulation layer (production of substrate with oligomer encapsulation layer formed)

The substrate with an oligomer encapsulation layer according to Example 3-1 was prepared in the same manner as the preparation of the substrate with an oligomer encapsulation layer according to Example 2-1.

(3-3) Preparation of adhesive composition

The following materials (polymer (polymer component), crosslinking agent, low molecular weight compound having a polymerizable functional group, photopolymerization initiator, and diluting solvent) were mixed and sufficiently stirred to prepare an adhesive liquid for application according to Example 3-1.

The acrylic acid ester copolymer contains 80.8 mass% of 2-ethylhexyl acrylate, 12.0 mass% of acryloylmorpholine (monomer having a nitrogen-containing functional group), 7.0 mass% of 4-hydroxybutylacrylate, and 0.2 mass% of acrylic acid. was copolymerized to prepare a polymer with a weight average molecular weight of 120,000.

- Crosslinking agent: Aliphatic isocyanate containing hexamethylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd.; [Coronate HX], 7.4 parts by mass (solid content)

- Low molecular weight compound having a polymerizable functional group: propoxylated bisphenol A diacrylate [manufactured by Shinnakamura Chemical Co., Ltd.; A-BPP-3] 23.3 parts by mass (solid content)

Photopolymerization initiator: 2-hydroxy-1-{4-[4-(2-hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one [IGM Resin company] manufacturing ; Omnirad 127〕4.1 parts by mass (solid content)

· Diluting solvent: Ethyl acetate was used, and the solid content concentration of the adhesive liquid for application was adjusted to 30% by mass.

(3-4) Production of adhesive layer

The adhesive layer according to Example 3-1 is obtained by changing the adhesive liquid for application in “(2-4) Production of the adhesive layer” of Example 2-1 to the adhesive liquid for application according to Example 3-1. It was produced in the same manner as in Example 2-1 except that it was made.

[Example 3-2]

Propoxylated bisphenol A diacrylate in Example 3-1 (manufactured by Shinnakamura Chemical Co., Ltd.; A-BPP-3], 1,6-hexanediol diacrylate [manufactured by Shinnakamura Chemical Co., Ltd.; The adhesive sheet of Example 3-2 was obtained in the same manner as Example 3-1, except that it was changed to [A-HD-N] (chain length between functional groups: 4).

[Example 3-3]

Propoxylated bisphenol A diacrylate in Example 3-1 (manufactured by Shinnakamura Chemical Co., Ltd.; A-BPP-3], tripropylene glycol diacrylate [manufactured by Shinnakamura Chemical Co., Ltd.; The adhesive sheet of Example 3-3 was obtained in the same manner as Example 3-1, except that it was changed to [APG-200] (chain length between functional groups: 6).

[Example 3-4]

Propoxylated bisphenol A diacrylate in Example 3-1 (manufactured by Shinnakamura Chemical Co., Ltd.; A-BPP-3], 1,9-nonanediol diacrylate [manufactured by Shinnakamura Chemical Co., Ltd.; The adhesive sheet of Example 3-4 was obtained in the same manner as Example 3-1, except that it was changed to [A-NOD-N] (chain length between functional groups: 9).

[Example 3-5]

Propoxylated bisphenol A diacrylate in Example 3-1 (manufactured by Shinnakamura Chemical Co., Ltd.; A-BPP-3], 1,10-decanediol diacrylate [manufactured by Shinnakamura Chemical Co., Ltd.; The adhesive sheet of Example 3-5 was obtained in the same manner as Example 3-1, except that it was changed to [A-DOD-N] (chain length between functional groups: 10).

[Example 3-6]

The acrylic acid ester copolymer in Example 3-1 was changed to that in Example 2-5, and further propoxylated bisphenol A diacrylate [manufactured by Shinnakamura Chemical Co., Ltd.; A-BPP-3], 1,10-decanediol diacrylate [manufactured by Shinnakamura Chemical Co., Ltd.; The adhesive sheet of Example 3-6 was obtained in the same manner as Example 3-1, except that it was changed to [A-DOD-N] (chain length between functional groups: 10).

[Example 3-7]

The acrylic acid ester copolymer in Example 3-1 was changed to that in Example 2-5, and further propoxylated bisphenol A diacrylate [manufactured by Shinnakamura Chemical Co., Ltd.; A-BPP-3], polypropylene glycol #400 diacrylate [manufactured by Shinnakamura Chemical Co., Ltd.; The adhesive sheet of Example 3-7 was obtained in the same manner as Example 3-1, except that it was changed to [APG-400] (chain length between functional groups: 14).

[Example 3-8]

The acrylic acid ester copolymer in Example 3-1 was changed to that in Example 2-5, and further propoxylated bisphenol A diacrylate [manufactured by Shinnakamura Chemical Co., Ltd.; A-BPP-3], polypropylene glycol (#700) diacrylate [manufactured by Shinnakamura Chemical Co., Ltd.; The adhesive sheet of Example 3-8 was obtained in the same manner as Example 3-1, except that it was changed to [APG-700] (number of carbon atoms in the chain between functional groups: 24).

The evaluation results of the adhesive sheets related to Examples 3-1 to 3-8 are shown in Table 3.

In addition, in order to evaluate the adhesive sheets related to Examples 3-1 to 3-8, the evaluation results of the adhesive sheets related to Examples 1-3, Example 2-1, and Comparative Example 1-1 as objects of comparison Also included in Table 3.

[Evaluation results]

According to the adhesive sheets related to Examples 3-1 to 3-8, the results of the second glue residual evaluation were good compared to Comparative Example 1-1.

According to the adhesive sheets according to Examples 3-1 to 3-5, peelability could be improved. After heating Example 2-1 using HEA as the functional group-containing monomer, the adhesive force to polyimide at room temperature was slightly high, but Example 3-1 to Example 3-5 using 4-HBA as the functional group-containing monomer. The adhesive sheet related to this exhibits adequate adhesive strength to polyimide at room temperature and has improved peelability.

When comparing Example 3-1 with the adhesive sheets related to Examples 3-2 to 3-6, the adhesive sheets related to Examples 3-2 to 3-6 were excellent in initial adhesion.

In Example 3-1, an energy ray curable compound having a cyclic structure was used as the energy ray curable compound. In Examples 3-2 to 3-6, when an energy ray curable compound having a predetermined chain structure was used, the initial adhesion was improved. It is believed that the Young's modulus was lowered and the initial adhesion was improved by using an energy ray-curable compound having a predetermined chain-like structure rather than a cyclic structure.

The adhesive sheets related to Examples 3-6 to 3-8 did not contain ACMO as a structural unit of the polymer component, but the effect of preventing glue residue was improved by using an energy ray curable compound having a predetermined chain structure. .

Comparing Examples 1-3, 2-1, and 3-1, the results of the first full residual evaluation were all A judgments, but the results of the second full residual evaluation under more stringent conditions were Example 1-3. This was the D judgment, and Examples 2-1 and 3-1, which used ACMO having a nitrogen-containing functional group as the monomer of the polymer component, were the A judgment.

10, 10A, 10B: Adhesive sheet
11: Description
11a: first substrate surface
11b: second substrate surface
12: Adhesive layer
13, 13A, 13B: Oligomer encapsulation layer
RL: Release sheet

Claims (23)

It has a base material and an adhesive layer,
The adhesive layer includes a cured product of an energy ray curable component and a polymer component,
The polymer component is at least one selected from the group consisting of (meth)acrylic resin, polyester resin, polyurethane resin, acrylic urethane resin, silicone resin, rubber resin, and polystyrene resin,
The energy ray curable component includes a multifunctional energy ray curable compound,
The multifunctional energy ray-curable compound has two or more polymerizable functional groups in one molecule,
A methylene group bonded in a straight chain exists between the first polymerizable functional group and the second polymerizable functional group, which are arbitrarily selected from two or more polymerizable functional groups of the multifunctional energy ray-curable compound,
The number of linearly bonded methylene groups present between the first polymerizable functional group and the second polymerizable functional group is 8 or more and 30 or less,
Adhesive sheet for electronic component processing. According to claim 1,
The polymer component is a (meth)acrylic resin,
Adhesive sheet. According to claim 1,
The polymer component includes a structural unit derived from a monomer having a nitrogen-containing functional group, provided that the nitrogen-containing functional group does not contain an NH bond.
Adhesive sheet. According to claim 1,
The polymer component includes structural units derived from a functional group-containing monomer having a reactive functional group,
The reactive functional group is bonded to the main chain of the polymer component through three or more linearly bonded methylene groups,
Adhesive sheet. The method according to any one of claims 1 to 4,
The multifunctional energy ray-curable compound has 2 to 5 polymerizable functional groups in one molecule,
Adhesive sheet. delete delete According to claim 5,
The multifunctional energy ray curable compound has a cyclic structure in the molecule,
Adhesive sheet. According to claim 8,
The breaking strength per unit cross-sectional area of the adhesive layer is 4.5 N/㎟ or more,
Adhesive sheet. The method according to any one of claims 1 to 4,
An adhesive sheet whose adhesive strength to polyimide at 100°C is 0.04 N/25 mm or more. According to claim 10,
The adhesive strength of the adhesive sheet to polyimide at 100°C is 0.06 N/25 mm or more,
The breaking strength per unit cross-sectional area of the adhesive layer is 4.5 N/mm2 or more,
Adhesive sheet. The method according to any one of claims 1 to 4,
The adhesive strength of the adhesive sheet to polyimide at 25°C after heat treatment at 190°C for 1.5 hours in a nitrogen atmosphere is 3 N/25 mm or less.
Adhesive sheet. The method according to any one of claims 1 to 4,
The Young's modulus of the adhesive layer is 5 MPa or less,
Adhesive sheet. The method according to any one of claims 1 to 4,
Used for fixing or protecting electronic components when processing them,
Adhesive sheet. According to claim 14,
The electronic component is a semiconductor device,
Used to fix the semiconductor element when sealing the semiconductor element,
Adhesive sheet. The method according to any one of claims 1 to 4,
Electronic components are directly attached to the adhesive layer,
Adhesive sheet. The method according to any one of claims 1 to 4,
An adhesive sheet in which the polymer component is crosslinked by a crosslinking agent. The method according to any one of claims 1 to 4,
An adhesive sheet wherein the polymer component is a (meth)acrylic polymer. According to claim 3,
The adhesive sheet wherein the nitrogen-containing functional group is at least one selected from the group consisting of a tertiary amino group, an aminocarbonyl group, a cyano group, and a nitrogen-containing heterocyclic group. According to claim 3,
The monomer having the nitrogen-containing functional group is at least one selected from the group consisting of heterocyclic vinyl compounds, (meth)acrylamide compounds, amino group-containing (meth)acrylic acid ester compounds, and (meth)acrylonitrile. An adhesive sheet. According to claim 3,
An adhesive sheet, wherein the ratio of structural units derived from the monomer having the nitrogen-containing functional group to the total mass of the polymer component is 1% by mass or more and 20% by mass or less. The method according to any one of claims 1 to 4,
An adhesive sheet, wherein the ratio of the cured product obtained by curing the energy ray curable component to the total mass of the adhesive layer is 5 mass% or more and 40 mass% or less. A process of fixing a semiconductor element on an adhesive sheet having an adhesive layer containing a cured product of an energy-ray curable component and a polymer component;
Including a process of encapsulating the semiconductor device with an encapsulating material,
The polymer component is at least one selected from the group consisting of (meth)acrylic resin, polyester resin, polyurethane resin, acrylic urethane resin, silicone resin, rubber resin, and polystyrene resin,
The energy ray curable component includes a multifunctional energy ray curable compound,
The multifunctional energy ray-curable compound has two or more polymerizable functional groups in one molecule,
A methylene group bonded in a straight chain exists between the first polymerizable functional group and the second polymerizable functional group, which are arbitrarily selected from two or more polymerizable functional groups of the multifunctional energy ray-curable compound,
The number of linearly bonded methylene groups present between the first polymerizable functional group and the second polymerizable functional group is 8 or more and 30 or less,
Method for manufacturing semiconductor devices.