JP2002256235A - Adhesive sheet, method for producing semiconductor device and semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an adhesive sheet capable of relaxing a thermal stress between a chip and a wiring connecting substrate, and having wafer fixing functions and die-bonding functions. SOLUTION: This adhesive sheet has an adhesive layer usable as a die- bonding agent on a radiation-polymerizable substrate. Thereby, the adhesive sheet having both the wafer fixing functions and the die-bonding functions at the same time can be provided. The adhesive layer has two kinds of resins causing phase separation in a B-stage state in which the resin (A) forming the dispersed phase in the B-stage state and the resin (B) forming the continuous phase as the adhesive layer. The resin (A) has <=10,000 weight-average molecular weight in an uncured state and the resin (B) has >=100,000 weight-average molecular weight in an uncured state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive sheet used for manufacturing a semiconductor device, and more particularly to an adhesive sheet having both a wafer fixing function at the time of dicing and an adhesive function for fixing a chip on a lead frame. About.

[0002]

2. Description of the Related Art Processes for semiconductor devices such as silicon and gallium arsenide include a pre-process in which elements are formed in a large-diameter semiconductor wafer state, and a process in which a wafer is separated into element pieces (chips) and finished into a final product. Process.

In a subsequent process, first, the semiconductor wafer is cut and separated (diced) for each chip. At this time, the semiconductor wafer is diced, washed, dried, and the adhesive sheet is stretched in a state where the semiconductor wafer is attached to the adhesive sheet in advance. (Expanding) and peeling (pickup) of chips from the adhesive sheet are added. This is followed by a die bonding step of the chip on the lead frame.

An adhesive sheet used in a process from a dicing process of a semiconductor wafer to a pickup process is:
From the dicing step to the drying step, it is necessary to maintain a sufficient adhesive strength to the chip, and it is desired that the chip has good releasability so that the adhesive does not adhere to the chip during pickup. I have.

When the picked-up chip is die-bonded to a lead frame, the chip is bonded to the lead frame via a die bonding adhesive such as an epoxy adhesive. Therefore, it is necessary to apply an adhesive to the back surface of the chip. However, if the chip is very small, it is difficult to apply an appropriate amount of adhesive to the chip. When the chip is large, it is not always easy to perform bonding so as to have an appropriate adhesive force, such as a shortage of adhesive. In addition, such an operation of applying the die bonding adhesive is complicated, and simplification of the process is also required.

Recently, various types of pressure-sensitive adhesive sheets for attaching wafers (hereinafter referred to as “adhesive sheets”) having both a wafer fixing function and a die bonding function have been proposed (for example, Japanese Patent Application Laid-Open No. 2-32181; Kaihei 3-2683
No. 45, Japanese Patent Publication No. 3-34853, etc.).

JP-A-2-32181 discloses a composition comprising a (meth) acrylate copolymer, an epoxy resin, a photopolymerizable low-molecular compound, a heat-active latent epoxy resin curing agent and a photopolymerization initiator. An adhesive tape comprising an adhesive layer formed from a product and a substrate is disclosed. The adhesive layer has a function of fixing the wafer at the time of wafer dicing, and after the dicing is completed, is hardened by irradiating with an energy ray, and the adhesive strength between the substrate and the base material is reduced. Therefore, when the chip is picked up, the adhesive layer peels off together with the chip. I with adhesive layer
When the C chip is placed on the lead frame and heated, the adhesive layer develops an adhesive force, and the bonding between the IC chip and the lead frame is completed.

Further, Japanese Patent Publication No. 3-34853 discloses that
A dicing film comprising a polymer support film having a surface substantially free of a release layer and a conductive adhesive is taught. This conductive adhesive has substantially the same function as the above-mentioned adhesive layer.

Further, in Japanese Patent Application Laid-Open No. 3-268345, an adhesive layer for bonding a die is provided on a heat-foamable pressure-sensitive adhesive layer provided on a supporting substrate. There is taught a die-bonding sheet having a function of supporting a semiconductor wafer at the time of dividing the semiconductor wafer so that the heat-foamable pressure-sensitive adhesive layer can be peeled off.

By using an adhesive sheet having both a wafer fixing function and a die bonding function as described above,
So-called direct die bonding can be performed, and the step of applying the die bonding adhesive can be omitted. Since there is no need to newly apply an adhesive for the die bonding step, the process can be simplified.

[0011]

In recent years, with the trend of miniaturization and high-frequency operation of electronic equipment, it is required that a semiconductor package to be mounted on the electronic equipment be mounted on a substrate at a high density. I'm advancing. Also, a micro BG in which external terminals are arranged in an area array below the package
Small packages called A (ball grid array) and CSP (chip size package) are also being developed.

As a semiconductor package, for example, a semiconductor chip is mounted on an organic resin substrate such as a glass epoxy substrate having a two-layer wiring structure or a polyimide substrate having a single-layer wiring structure via an insulating adhesive. The terminal and the terminal on the wiring board side are connected by wire bonding or inner bonding method of TAB (Tape Automated Bonding), and the connection portion and the upper surface or the end surface of the chip are made of epoxy-based sealing material or epoxy-based liquid sealing material. A structure in which metal terminals such as solder balls are arranged in an area array on the back surface of a wiring board is employed.

When mounting these semiconductor packages on an electronic device substrate, they are often mounted at a high density and collectively using a solder reflow method. At this time, the entire semiconductor package is exposed to a high temperature of 210 to 260 ° C.

As described above, the semiconductor chip is mounted on the wiring connection board such as TAB via the insulating adhesive, but when the difference in thermal expansion coefficient between the chip and the wiring connection board is large, Package cracks (also called reflow cracks) may occur during solder reflow.

In view of the above-mentioned conventional problems, an object of the present invention is to provide an adhesive sheet having both a wafer fixing function and a die attaching function, and capable of suppressing occurrence of the above-mentioned reflow crack in a semiconductor manufacturing process. That is. Another object of the present invention is to provide a method for manufacturing a semiconductor device using the adhesive sheet and a semiconductor device.

[0016]

Means for Solving the Problems The adhesive sheet of the present invention comprises:
A resin having a radiation-polymerizable base material and an adhesive layer formed on the base material, wherein the adhesive layer has a continuous phase with a resin (A) forming a dispersed phase that undergoes phase separation in a B-stage state; Wherein the resin (A) has a weight average molecular weight of 10,000 or less in an uncured state, and the resin (B) comprises:
The weight-average molecular weight in an uncured state is 100,000 or more.

The method of manufacturing a semiconductor device according to the present invention comprises the steps of: adhering the adhesive sheet of the present invention to a semiconductor wafer with the adhesive layer as an adhesive surface; dicing the semiconductor wafer; A step of irradiating radiation from the base material side, a step of peeling the semiconductor chip with the adhesive layer adhered from the base material of the adhesive sheet, and the peeling the semiconductor chip on a wiring connection substrate such as a lead frame. Bonding through an adhesive layer.

A semiconductor device according to the present invention is a device manufactured by using the above-described method for manufacturing a semiconductor device according to the present invention.

According to the adhesive sheet and the method of manufacturing a semiconductor device using the same according to the present invention, since the adhesive sheet has a radiation-polymerizable substrate, it is polymerized and cured by irradiation with radiation, and adheres to the substrate. Adhesion with the agent layer can be adjusted. Therefore, the adhesive sheet of the present invention can be used as an adhesive sheet for fixing a wafer at the time of dicing in the process of manufacturing a semiconductor device. The adhesiveness between the substrate and the adhesive layer is reduced, and the chip can be easily peeled off from the base material while the adhesive layer is provided. Thereafter, the peeled chip can be adhered to a wiring connection substrate such as a lead frame or TAB via an adhesive layer.

Further, the adhesive sheet of the present invention has a sufficient adhesive force as a die bonding material at room temperature, and the resin (A) forms an island-like dispersed phase with the adhesive layer in a B-stage state. Since the resin (B) forms a sea-like continuous phase, the elastic modulus in the B-stage state can be adjusted to be low. That is, in a high-temperature process such as a solder reflow process, the adhesive layer is in a B-stage state having a low elastic modulus, so that stress caused by a difference in thermal expansion coefficient between the semiconductor chip and the wiring connection board is reduced, and cracks are suppressed. it can. Therefore,
The semiconductor device manufactured by the above-described method for manufacturing a semiconductor device using the adhesive sheet of the present invention does not cause a package crack or the like even at a high temperature.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the adhesive sheet of the present invention will be described.

The adhesive sheet according to the embodiment of the present invention
It is composed of a radiation polymerizable base material and an adhesive layer for die bonding formed on the base material.
By irradiating radiation such as EB (electron beam) or the like, the adhesive force between the base material and the adhesive layer for die bonding is adjusted, so that a semiconductor wafer bonding adhesive having both a wafer fixing function and a die bonding function is provided. It is a sheet.

As the radiation-polymerizable substrate of the present embodiment, a resin film containing a component having a radiation-polymerizable functional group or a resin having a radiation-polymerizable functional group in the form of a film is used. Can be used.

Examples of the resin used for the base material include thermoplastic resins such as ethylene-vinyl acetate copolymer, ethylene-acrylate copolymer, polyamide, polyethylene, and polysulfone, epoxy resins, polyimide resins, silicone resins, and phenol resins. Or other thermosetting resin, or
An acrylic resin, a rubber-based polymer, a fluororubber-based polymer, a fluororesin, etc. may be mentioned, and a radiation-polymerizable component is mixed into these resins, or a modified resin obtained by adding a radiation-polymerizable functional group to these resins is used. . Also, a mixture of two or more of these may be used.

As the radiation-polymerizable functional group in the substrate, a compound having at least one carbon-carbon double bond in the molecule can be used.

Further, the radiation polymerizable base material includes
A reactive diluent may be added as needed. As the reactive diluent, a polymerizable compound having a molecular weight of about 100 to 3000, preferably about 100 to 1500 and having at least one carbon-carbon double bond in the molecule is used. Specifically, trimethylol propane triacrylate, tetramethylol methane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate or 1,4-butylene glycol diacrylate, One or more of 1,6-hexanediol diacrylate, polyethylene glycol diacrylate, commercially available oligoester acrylate, and the like are used. The reactive diluent is preferably used in an amount of 0 to 50 parts by weight, particularly preferably 0 to 30 parts by weight, based on 100 parts by weight of the resin.

The above-mentioned substrate having radiation polymerizability includes:
A photoreaction initiator may be mixed. When a photoreaction initiator is mixed, the polymerization curing time by light irradiation and the amount of light irradiation can be reduced. As such a photoreaction initiator, specifically, benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether,
Examples include benzyldiphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, dibenzyl, diacetyl, β-chloranthraquinone, and the like. The photoreaction initiator is preferably used in an amount of 0.1 to 10 parts by weight, particularly 0.5 to 5 parts by weight, based on 100 parts by weight of the resin.

Next, the adhesive layer of the present embodiment formed on the above-described base material undergoes phase separation in the B-stage state.
And a resin (A) that forms a dispersed phase and a resin (B) that forms a continuous phase.

Here, the B-stage state means a heated semi-cured state of the resin, and more specifically, using a DSC (Differential Scanning Calorimeter).
The value obtained by measuring the heat value of curing is 10 to 40% of the heat value of curing of the composition in the uncured state.

Examples of the resin (A) that forms a dispersed phase in the B-stage state include epoxy resin, cyanate ester resin, cyanate resin, silicone resin, acrylic rubber having a functional group such as epoxy group and carboxyl group, epoxy group and carboxyl group. Modified resins such as butadiene rubber having a functional group such as a group and silicone-modified polyamideimide can be used. Among them, epoxy resin is preferable in terms of high adhesiveness and heat resistance. Any epoxy resin may be used as long as it cures and exhibits an adhesive action. An epoxy resin having two or more functional groups and an average molecular weight of 5,000 or less, preferably 3000 or less is used. If the molecular weight is too large, the liquid will not be liquid and handling will be difficult. Examples of the bifunctional epoxy resin include bisphenol A type and bisphenol F type resins. Bisphenol A type or bisphenol F type liquid resin is
From Yuka Shell Epoxy Co., Ltd., Epicoat 807,
It is commercially available under the trade names Epicoat 827 and Epicoat 828. In addition, Dow Chemical Japan Co., Ltd. E. FIG. R. 330, D.I. E. FIG. R. 331;
E. FIG. R. 361. Further, YD8125, YDF81 from Toto Kasei Co., Ltd.
It is marketed under the trade name 70.

As the epoxy resin, a polyfunctional epoxy resin may be added for the purpose of increasing the Tg (glass transition temperature). Examples of the polyfunctional epoxy resin include a phenol novolak type epoxy resin and a cresol novolak type epoxy resin. You. The phenol novolak epoxy resin is commercially available from Nippon Kayaku Co., Ltd. under the trade name EPPN-201. Cresol novolak type epoxy resin was obtained from Sumitomo Chemical Co., Ltd. as ESCN-1.
90, sold under the trade name ESCN-195. Also, from Nippon Kayaku Co., Ltd., EOCN1012,
It is commercially available under the trade names EOCN1025 and EOCN1027. In addition, YDC
N701, YDCN702, YDCN703, YDCN
It is marketed under the trade name 704.

As the curing agent for the epoxy resin, those usually used as curing agents for the epoxy resin can be used, and amine, polyamide, acid anhydride, polysulfide, boron trifluoride and phenolic hydroxyl group are contained in one molecule. And bisphenol A, bisphenol F, bisphenol S, etc., which are compounds having at least one compound. In particular, it is preferable to use a phenol resin such as a phenol novolak resin or a bisphenol novolak resin because of its excellent electric corrosion resistance during moisture absorption. Phenol novolak resin is Barcam TD-2090 and Barcam TD-2131 from Dainippon Ink and Chemicals, Inc. Bisphenol novolak resin is phenolite LF2 from Dainippon Ink and Chemicals, Inc.
882 and Phenolite LF2822. The amount of the curing agent used is preferably an amount containing a functional group 0.8 to 1.2 times the chemical equivalent of the epoxy resin.

Examples of the resin (B) that forms a continuous phase in the B-stage state include acrylic rubber which is a copolymer of acrylate, methacrylate and acrylonitrile, butadiene rubber containing styrene and acrylonitrile, silicone resin, Modified resins such as silicone-modified polyamide imides are exemplified. When a high molecular weight component having a weight average molecular weight of 100,000 or more is used, the handleability as a film is good. Furthermore,
When an acrylic copolymer having a Tg containing glycidyl methacrylate or glycidyl acrylate of 2 to 6% by weight and having a Tg of −10 ° C. or more and a weight average molecular weight of 800,000 or more is used, adhesiveness and heat resistance are particularly preferable. . Glycidyl methacrylate or glycidyl acrylate 2-6
Acrylic copolymer having a Tg containing at least 10% by weight and a weight average molecular weight of at least 800,000 is HTR-8.
60P-3 (trade name, manufactured by Teikoku Chemical Industry Co., Ltd.) can be used. The amount of glycidyl methacrylate or glycidyl acrylate used as the functional group monomer is 2
Preferably, the copolymer ratio is ６6% by weight. The content is preferably 2% by weight or more because higher adhesive strength is obtained, and is preferably 6% by weight or less because gelation of rubber is reduced. The remainder can be an alkyl acrylate such as methyl acrylate or methyl methacrylate having an alkyl group having 1 to 8 carbon atoms, an alkyl methacrylate, or a mixture thereof with styrene, acrylonitrile, or the like.

The curing accelerator is a substance which has compatibility with the resin (A) of the dispersed phase discontinuous in the form of islands in the B-stage state and is phase-separated from the resin (B) which is the continuous phase of the sea. It is desirable. That is, the same polarity as the resin (A) of the island-shaped dispersed phase,
It is preferable that the resin has a molecular structure and a polarity and a molecular structure that are significantly different from those of the resin (B) that is a sea-like continuous phase.

For example, when the resin phase that is discontinuously dispersed in an island shape is a phase containing an epoxy resin and a curing agent as main components and the other continuous phase is an acrylic rubber, the curing accelerator is an epoxy compound and an imidazole. Preferred are addition compounds with compounds, addition compounds with epoxy compounds and dialkylamines, and the like. Further, those in which the epoxy compound has a long chain are particularly preferred. Particularly, those having an adduct-type structure are preferable in that the activity at room temperature can be reduced. An adduct-type structure is an addition compound obtained by reacting a compound having catalytic activity with various compounds, such as an imidazole compound or a compound having a 1,2,3 tertiary amino group. Amines are referred to as amine adduct types. Furthermore, there are an amine-epoxy adduct, an amine-urea adduct, an amine-urethane adduct, etc., depending on the type of raw material. An amine-epoxy adduct is particularly preferred in that it does not foam during curing, has low elasticity, and provides a cured adhesive product having good heat resistance and moisture resistance.

Examples of the epoxy compound used as a raw material for producing the amine-epoxy adduct latent curing accelerator include polyphenols such as bisphenol A, bisphenol F, catechol and resorcinol, and polyhydric phenols such as glycerin and polyethylene glycol. Polyglycidyl ether obtained by reacting alcohol and epichlorohydrin, or p-hydroxybenzoic acid,
Glycidyl ether esters obtained by reacting a hydroxycarboxylic acid such as β-hydroxynaphthoic acid with epichlorohydrin, or polyglycidyl esters obtained by reacting a polycarboxylic acid such as phthalic acid or terephthalic acid with epichlorohydrin, or 4,4 Glycidylamine compounds obtained by reacting epichlorohydrin with '-diaminodiphenylmethane, m-aminophenol, etc., and further, polyfunctional epoxy compounds such as epoxidized phenol novolak resin, epoxidized cresol novolak resin, epoxidized polyolefin, and butyl glycidyl Ether, phenylglycidyl ether,
Examples include, but are not limited to, monofunctional epoxy compounds such as glycidyl methacrylate.

The amines used as a raw material for producing the amine-epoxy adduct latent curing accelerator have at least one active hydrogen in the molecule capable of undergoing an addition reaction with an epoxy group, and have a primary amino group, Any compound having at least one substituent selected from a tertiary amino group and a tertiary amino group in the molecule may be used. Such amines include:
For example, aliphatic amines such as diethylenetriamine, triethylenetetramine, n-propylamine, 2-hydroxyethylaminopropylamine, cyclohexylamine, 4,4′-diamino-dicyclohexylmethane,
Aromatic amines such as 4,4'-diaminodiphenylmethane, 2-methylaniline, 2-ethyl-4-methylimidazole, 2-methylimidazole, 2-ethyl-4
Cyclic amine compounds such as -methylimidazoline, 2,4-dimethylimidazoline, piperidine and piperazine, but are not limited thereto. Among these compounds, a compound having a tertiary amino group is particularly preferable because it gives a curing accelerator having extremely high potential. Such compounds are set forth below, but are not limited thereto. For example, aliphatic amine compounds such as dimethylaminopropylamine, diethylaminopropylamine, di-n-propylaminopropylamine, dibutylaminopropylamine, dimethylaminoethylamine, diethylaminoethylamine, N-methylpiperazine, and 2-methylimidazole And primary or secondary amines having a tertiary amino group in the molecule, such as imidazole compounds such as, 2-ethylimidazole, 2-ethyl-4-methylimidazole and 2-phenylimidazole.

Representative examples of the adduct-type curing accelerator used in the present embodiment are shown below, but are not limited thereto. As the amine-epoxy adduct system, Amicour PN-23, Amicure MY-24, Amicure MY-D, Amicure MY from Ajinomoto Co., Ltd.
-H, etc. from HRC, Inc. Hardner X-3615S, Hardner X-3293S, etc., from Asahi Kasei Corporation, Novacure HX-3748, Novacure HX-3088, etc., from Pacific Anchor Chemical Ancamine2014AS, Ancamine.
e2014FG and the like are commercially available under the above trade names. Further, as an amine-urea type adduct system, it is commercially available from Fuji Kasei Co., Ltd. under the trade names of Fujicure FXE-1000 and Fujicure FXR-1030.

The compounding amount of the latent curing accelerator is preferably
0.1 to 20 parts by weight, more preferably 1.0 to 15 parts by weight, based on 100 parts by weight of the total of the resin (A) and the curing agent of the dispersed phase.
Parts by weight. If the amount is less than 0.1 part by weight, the curing rate tends to be low, and if it exceeds 20 parts by weight, the usable life tends to be short.

In addition, various imidazoles and the like may be used together as a curing accelerator to such an extent that storage stability is not impaired. As imidazole, 2-methylimidazole,
2-ethyl-4-methylimidazole, 1-cyanoethyl-2-phenylimidazole, 1-cyanoethyl-2
-Phenylimidazolium trimellitate and the like. Imidazoles were purchased from Shikoku Chemicals Co., Ltd.
It is commercially available as E4MZ, 2PZ-CN, 2PZ-CSN.

In addition, a filler may be added to the adhesive layer for the purpose of adjusting fluidity and improving moisture resistance. Such fillers include silica, diantimony trioxide, and the like.

Further, a coupling agent may be added to the adhesive layer of the present embodiment in order to improve interfacial bonding between different kinds of materials. As the coupling agent, a silane coupling agent is preferable. As the silane coupling agent, γ-glycidoxypropyltrimethoxysilane,
γ-mercaptopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-ureidopropyltriethoxysilane, N-β-aminoethyl-γ-aminopropyltrimethoxysilane, and the like. The above-mentioned silane coupling agent is such that γ-glycidoxypropyltrimethoxysilane is NUC A-187 and γ-mercaptopropyltrimethoxysilane is NUC A-18.
9, γ-aminopropyltriethoxysilane is NUC
A-1100, γ-ureidopropyltriethoxysilane is NUC A-1160, N-β-aminoethyl-γ
-Aminopropyltrimethoxysilane is NUC A-1
All are commercially available from Nihon Unicar Co., Ltd. under the trade name of 120. The amount of the coupling agent to be added is 0.1 to 10 parts by weight based on 100 parts by weight of the composition forming each of the dispersed phase and the continuous phase in view of the effect, heat resistance and cost of the addition. Is preferred.

Further, an ionic impurity can be attached to the adhesive of the adhesive layer of the present embodiment, and an ion scavenger can be blended in order to improve insulation reliability when absorbing moisture.

The adhesive layer is formed by dissolving or dispersing the above-mentioned components of the adhesive in a solvent to form a varnish, applying the solution on a carrier film, heating and removing the solvent.

As a solvent used for preparing a varnish, it is preferable to use relatively low boiling point methyl ethyl ketone, acetone, methyl isobutyl ketone, 2-ethoxyethanol, toluene, butyl cellosolve, methanol, ethanol, 2-methoxyethanol and the like. . Further, a high boiling point solvent may be added for the purpose of improving the coating properties.
Examples of the high boiling point solvent include dimethylacetamide, dimethylformamide, methylpyrrolidone, cyclohexanone and the like.

As a method of manufacturing the adhesive sheet of the present embodiment, for example, first, an adhesive layer and a radiation-polymerizable base material are respectively applied to a film-like support member, dried, and then the adhesive layer and the radiation-polymerizable material are dried. Room temperature substrate,
In some cases, there is a method of laminating while applying heat and pressure. Alternatively, after forming the adhesive layer or the base material, a radiation-polymerizable base material or the adhesive layer may be formed using the adhesive layer or the base material as a supporting member. The support member may be peeled off after being bonded, but may be bonded as a protective material before use. It is preferable from the viewpoint of workability that the surface opposite to the surface on which the adhesive layer is formed of the radiation polymerizable substrate is polymerized by irradiation with radiation before or after the formation of the adhesive layer. The shape of the adhesive sheet is not particularly limited. Any shape such as a tape shape and a label shape may be used.

A method for manufacturing a semiconductor device using the adhesive sheet according to the present embodiment will be described. That is, first, a semiconductor wafer to be diced is pressure-bonded to a die bonding adhesive layer of an adhesive sheet at room temperature or while heating. In this state, the wafer is diced, washed and dried. During these series of dicing steps, the wafer chips are sufficiently adhered and held to the base material of the adhesive sheet by the adhesive layer, so that the wafer chips do not fall off. Next, radiation such as ultraviolet light (UV) or electron beam (EB) is applied to the substrate side of the adhesive sheet, and the radiation-polymerizable substrate is polymerized and cured. As a result, the adhesive force between the radiation polymerizable substrate and the adhesive layer is reduced. The adhesive sheet is expanded (expanded) to increase the distance between the chips. Thereafter, the chip is picked up.
Since the adhesive strength between the base material and the adhesive layer has been sufficiently reduced by irradiation while maintaining the adhesiveness of the adhesive layer to the chip, each chip is peeled from the base material with the adhesive layer attached to the back surface. Is done.

The chip picked up together with the adhesive layer is pressure-bonded to a lead frame at room temperature or while heating. After the pressure bonding, the adhesive layer is heated. By this heating, the adhesive layer develops an adhesive force that resists reflow crack resistance, and the bonding between the chip and the lead frame is completed.

Thereafter, each chip is packaged through an electrical connection with a lead frame and a sealing step, and is mounted on a substrate of an electronic component through a solder reflow step. In addition, since the thermal stress caused by the difference in the thermal expansion coefficient between the chip and the substrate of the electronic component is reduced, the occurrence of reflow crack can be suppressed.

As described above, the adhesive sheet of the present invention
It is composed of a two-layer structure of a base material and an adhesive layer. Since the structure is simple, the film needs to be bonded only once, and the manufacturing process is simple. Further, the adhesive sheet of the present invention can be peeled off by irradiation of radiation because the base material has radiopolymerizability, but the radioactive polymerizability is given only to the base material, and the adhesive layer remaining on the back surface of the semiconductor chip has Since no radioactive polymerizing agent is added, the adhesive layer can be composed of a composition intended for a pure adhesive function. Therefore, by forming the adhesive layer having the above-described composition, it is possible to provide a sufficient adhesive force and a sufficient stress relaxation effect even at a high temperature. Therefore, the method for manufacturing a semiconductor device using the adhesive sheet of the present invention can provide a highly reliable semiconductor device that has a simple manufacturing process, high yield, and high yield.

[0051]

EXAMPLES <Preparation of Adhesive Layer> (Example 1) An epoxy resin was used as a resin (A) that forms a dispersed phase in the B-stage state. In particular,
As the epoxy resin, 45 parts by weight of a bisphenol A-type epoxy resin (epoxy equivalent: 200 parts by weight, using an Epicoat 828 manufactured by Yuka Shell Epoxy Co., Ltd.), a cresol novolak type epoxy resin (epoxy equivalent: 220
Uses ESCN001 manufactured by Sumitomo Chemical Co., Ltd.) 15
40 parts by weight of phenol novolak resin (Plyofen LF2882 manufactured by Dainippon Ink and Chemicals, Inc.) as a curing agent for epoxy resin, high molecular weight compatible with epoxy resin and having a weight average molecular weight of 30,000 or more As a resin, 15 parts by weight of a phenoxy resin (molecular weight: 50,000, using phenothoto YP-50 manufactured by Toto Kasei Co., Ltd.) was prepared. As the resin (B) that forms a continuous phase in the B-stage state, an epoxy group-containing acrylic rubber was used. Specifically, an epoxy group-containing acrylic rubber (molecular weight: 1,000,000, HTR-86 manufactured by Teikoku Chemical Industry Co., Ltd.)
NP-3) 150 parts by weight. Also, 0.5 parts by weight of a curing accelerator 1-cyanoethyl-2-phenylimidazole (Curesol 2PZ-CN) as a curing accelerator and γ-glycidoxypropyltrimethoxysilane (manufactured by Nippon Unicar Co., Ltd.) as a silane coupling agent N
Methyl ethyl ketone was added to a composition consisting of 0.7 parts by weight, stirred and mixed, and the mixture was degassed under vacuum to produce a varnish. This varnish was applied on a supporting member, and heated and dried at 140 ° C. for 5 minutes to form a coating film in a B-stage state, thereby producing an adhesive layer.

The degree of curing of the adhesive in this state was determined by DS
As a result of measurement (heating rate, 10 ° C./min) using C (a 912 type DSC manufactured by DuPont), 15% of the total curing heat generation was completed. Further, the storage elastic modulus of the cured adhesive is measured by a dynamic viscoelasticity measuring device (manufactured by Rheology, DVE-V).
As a result of measurement using 4) (sample size 20 mm length, width 4 mm, film thickness 80 μm, heating rate 5 ° C./min, tensile mode automatic static load), 360 MPa at 25 ° C., 2 MPa
It was 4 MPa at 60 ° C.

Example 2 The phenoxy resin used in Example 1 was replaced with a carboxyl group-containing acrylonitrile butadiene rubber (molecular weight: 400,000, PN manufactured by Nippon Synthetic Rubber Co., Ltd.).
R-1), and an adhesive layer was produced under the same conditions as in Example 1. The degree of curing of the adhesive in this state was measured using a DSC, and as a result, heat generation of 20% of the total curing calorific value was completed. As a result of measuring the storage elastic modulus of the cured adhesive using a dynamic viscoelasticity measuring apparatus, it was 300 MPa at 25 ° C. and 3 MPa at 260 ° C.

Example 3 10 parts by volume of silica was added to 100 parts by volume of the solid content of the adhesive of the adhesive varnish of Example 1, and a varnish kneaded with a bead mill for 60 minutes was used.
Thereafter, an adhesive layer was produced under the same conditions as in Example 1.
As a result of measurement using DSC, it was in a state where heat generation of 15% of the total curing heat generation was completed. As a result of measuring the storage elastic modulus of the cured adhesive using a dynamic viscoelasticity measuring apparatus, it was 1,500 MPa at 25 ° C. and 10 MPa at 260 ° C.

Example 4 An adhesive film was produced in the same manner as in Example 1 except that the phenoxy resin used in Example 3 was not used. As a result of measurement using DSC, it was in a state where heat generation of 15% of the total curing heat generation was completed. As a result of measuring the storage elastic modulus of the cured adhesive using a dynamic viscoelasticity measuring device, it was 350 MPa at 25 ° C. and 4 MPa at 260 ° C.

(Example 5) An adhesive layer was produced under the same conditions as in Example 1 except that the amount of the epoxy group-containing acrylic rubber in Example 1 was changed from 150 parts by weight to 50 parts by weight. As a result of measurement using DSC, the total curing calorific value was 2
It was in a state where heat generation of 0% was finished. As a result of measuring the storage elastic modulus of the cured adhesive, using a dynamic viscoelasticity measuring device,
It was 3,000 MPa at 25 ° C. and 5 MPa at 260 ° C.

(Example 6) An adhesive layer was produced under the same conditions as in Example 1 except that the amount of the epoxy group-containing acrylic rubber in Example 1 was changed from 150 parts by weight to 400 parts by weight. As a result of measurement using DSC, it was in a state where heat generation of 20% of the total curing heat generation was completed. As a result of measuring the storage elastic modulus of the cured adhesive using a dynamic viscoelasticity measuring device,
It was 200 MPa at 25 ° C. and 1 MPa at 260 ° C.

(Example 7) In addition to changing 150 parts by weight of the epoxy group-containing acrylic rubber of Example 3 to phenoxy resin (160 parts by weight of phenoxy resin), the adhesive layer was formed under the same conditions as in Example 1. Produced. As a result of measurement using DSC, the total curing calorific value was 20%. The storage elastic modulus was 3,400 MPa at 25 ° C and 3 MPa at 260 ° C.

Example 8 An adhesive film was produced in the same manner as in Example 1, except that the epoxy group-containing acrylic rubber in Example 1 was changed to acrylonitrile butadiene rubber. The total curing calorific value of this adhesive film was 20%. The storage modulus is 500 MPa at 25 ° C., 26
It was 2 MPa at 0 ° C.

<Preparation of Adhesive Sheet> The copolymerization ratio of methyl methacrylate / n-butyl methacrylate / 2-ethylhexyl acrylate / methacrylic acid is 5 by weight.
5/8/15/22 100 parts by weight of an acrylate copolymer (acid value 143.3, glass transition point 66.3 ° C, weight average molecular weight 80,000), trimethylolpropane triacrylate / polyethylene glycol dimethacrylate A composition consisting of 60 parts by weight of a mixture having a weight ratio of 20/10 // and 5 parts by weight of benzophenone was applied on a support material,
It was dried in an oven at 100 ° C. for 3 minutes to produce a radiation-polymerizable substrate.

<Preparation of Semiconductor Package> This base material was bonded to the adhesive films obtained in Examples 1 to 8 to prepare an adhesive sheet. One silicon wafer is placed on the obtained adhesive sheet.
After thermocompression bonding at 00 ° C 1Kg, 10mm to the adhesive layer
Then, the substrate was irradiated with ultraviolet rays (UV) at 500 mJ / cm ² using a high-pressure mercury lamp. The silicon chip cut after the UV irradiation was easily peeled off from the substrate together with the adhesive layer.

A semiconductor device having an adhesive layer adhered to the back surface was die-bonded to a flexible printed circuit board mainly composed of a polyimide film to produce a semiconductor device. A reflow crack resistance and a temperature cycle test of this semiconductor device were applied. Evaluation of reflow crack resistance
The maximum temperature of the sample surface is 240 ° C. The sample is passed through an IR (infrared) reflow furnace set to maintain this temperature for 20 seconds, and is cooled twice by leaving it at room temperature. Observation. Those with no cracks were evaluated as good, and those with cracks were evaluated as poor. In the temperature cycle test, the sample was left in an atmosphere of −55 ° C. for 30 minutes, and thereafter,
The number of cycles up to the occurrence of destruction is shown assuming that the step of leaving the substrate in a 5 ° C. atmosphere for 30 minutes is one cycle. The moisture resistance was evaluated by treating the semiconductor device sample in a pressure cooker tester for 96 hours (PCT treatment), and then observing peeling and discoloration of the adhesive film. A film in which no peeling or discoloration of the adhesive film was observed was regarded as good, and a film in which peeling or discoloration was observed was regarded as defective.

<Results> The material of the continuous phase resin (B) used in each Example is shown in the table of FIG. The properties of each adhesive layer such as heat resistance, moisture resistance, and elastic modulus are shown in the table of FIG.

In Examples 1, 2 and 3, the epoxy resin and its curing agent, the high molecular weight resin compatible with the epoxy resin, the epoxy group-containing acrylic copolymer, and the adhesive containing the curing accelerator were used. Example 4 is an adhesive containing both an epoxy resin and a curing agent thereof, an epoxy group-containing acrylic copolymer, and a curing accelerator, and is 300 to 1500 at 25 ° C., and 3 to 10 at 260 ° C. It exhibited a relatively low storage modulus. Further, all of them had good reflow crack resistance, temperature cycle test, and PCT resistance.

On the other hand, Example 5 is compared with Examples 1 to 4 because the storage modulus is high because the amount of the epoxy group-containing acrylic copolymer which becomes a continuous phase at the B stage is small and the stress cannot be sufficiently relaxed. The results of the reflow crack resistance and the temperature cycle test were inferior. In Example 6, the storage modulus was low and good because the amount of the epoxy group-containing acrylic copolymer was too large, but the handleability of the adhesive film was inferior to Examples 1 to 4. Further, in Example 7, since the composition did not contain the epoxy group-containing acrylic copolymer, the storage elastic modulus was high, and as in Example 5, the stress could not be relaxed. Was inferior to Examples 1-4. Example 8 does not contain an epoxy group-containing acrylic copolymer, contains other rubber components, has a low storage elastic modulus at 25 ° C., and has good reflow cracking properties, but is inferior in electrolytic corrosion resistance. There is a fear that migration of copper to copper may occur.

Considering conditions such as handleability of the adhesive layer, reflow crack resistance, and sufficient hardness at room temperature, the storage elastic modulus of the adhesive layer at 25 ° C. is 10 to 2000.
More preferably, it is 3-50 MPa at 260 degreeC and MPa.

[0067]

As described above, since the adhesive sheet of the present invention has an adhesive layer which can be used as a die bonding agent on a radioactive polymerizable substrate, it has a wafer fixing function and a die bonding function. Can be provided at the same time. Therefore, the method for manufacturing a semiconductor device of the present invention using the adhesive sheet can omit the step of bonding the die bonding adhesive.

In the adhesive sheet of the present invention, since the adhesive layer has heat resistance, moisture resistance, and a sufficiently low elastic modulus at high temperatures, the thermal stress between the chip after die bonding and the wiring connection board is reduced. Alleviates the occurrence of cracks in the semiconductor device in the high-temperature process. Therefore, the semiconductor device manufactured by the method for manufacturing a semiconductor device of the present invention using the adhesive sheet can provide a semiconductor device having no cracks and having high temperature stability.

[Brief description of the drawings]

FIG. 1 is a table showing resin materials forming a continuous phase of an adhesive layer according to an example of the present invention.

FIG. 2 is a table showing measurement results of heat resistance, moisture resistance, and elastic modulus of an adhesive layer of an adhesive sheet according to an example of the present invention and a semiconductor device using the adhesive sheet.

Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat II (Reference) H01L 21/78 Y (72) Inventor Katsuhide Aichi 48 Wadai, Tsukuba-shi, Ibaraki Pref. Hitachi Chemical Co., Ltd. (72 Inventor Teichi Inada 48 Wadai, Tsukuba, Ibaraki F-term in Hitachi Chemical Co., Ltd.F-term (reference)

Claims (14)

[Claims] 1. A radiation-polymerizable base material, and an adhesive layer formed on the base material, wherein the adhesive layer forms a dispersed phase that separates from each other in a B-stage state. Resin (A) and a resin (B) that forms a continuous phase, wherein the resin (A) has a weight average molecular weight of 10,000 or less in an uncured state, and the resin (B) has an uncured state. The weight-average molecular weight of the adhesive sheet is 100,000 or more. 2. The adhesive layer has a storage elastic modulus of 10 to 2000 MPa at 25 ° C. and a storage elastic modulus of 3 at 260 ° C.
The adhesive sheet according to claim 1, wherein the pressure is 50 MPa. 3. The adhesive sheet according to claim 1, wherein a volume ratio of the dispersed phase and the continuous phase in a B-stage state is 1: 0.3 to 1: 5. 4. The resin (A) is an epoxy resin, and the resin (B) is an acrylic copolymer.
4. The adhesive sheet according to any one of 3. 5. The adhesive sheet according to claim 1, wherein the disperse phase further has a curing agent. 6. The epoxy resin has at least two functional groups,
The adhesive sheet according to claim 4, having an average molecular weight of 5000 or less. 7. The acrylic copolymer according to claim 4, wherein the acrylic copolymer contains 2 to 6% by weight of glycidyl methacrylate or glycidyl acrylate, has a Tg of −10 ° C. or more and a weight average molecular weight of 800,000 or more. Adhesive sheet. 8. The adhesive sheet according to claim 4, wherein the epoxy resin and the acrylic polymer have a weight ratio of 3: 5 to 3:10. 9. The method according to claim 6, wherein the base material is a resin film containing a component having a radiation-polymerizable functional group, or a resin film having a resin having a radiation-polymerizable functional group. The adhesive sheet according to any one of claims 1 to 8, wherein 10. A step of attaching the adhesive sheet according to claim 1 to a semiconductor wafer using an adhesive layer as an adhesive surface; a step of dicing the semiconductor wafer; Irradiating the base material of the sheet with radiation from the base material side; separating the semiconductor chip with the adhesive layer adhered from the base material; and placing the separated semiconductor chip on a wiring connection board. Bonding the semiconductor device via the adhesive layer. 11. The method of manufacturing a semiconductor device according to claim 10, further comprising the step of electrically connecting said semiconductor chip and a wiring connection board. 12. The method according to claim 11, further comprising a step of sealing the semiconductor chip with a resin. 13. The method of manufacturing a semiconductor device according to claim 11, further comprising a step of mounting the semiconductor chip on a substrate of an electronic component by a semiconductor reflow method. 14. The method according to claim 10, wherein:
13. A semiconductor device manufactured by the method for manufacturing a semiconductor device according to the above section.