TW202239897A - Sheet for workpiece processing including a base material and an adhesive layer - Google Patents

Abstract

The present invention provides a sheet for workpiece processing having excellent antistatic properties and capable of properly suppressing occurrence of cutting chips. The sheet for workpiece processing includes a base material 11 and an adhesive layer 12 laminated on one side of the base material 11. The base material 11 includes a surface layer 111 adjacent to the adhesive layer 12, a back layer 113 away from the adhesive layer 12 and a middle layer 112 between the surface layer 111 and the back layer 113. The surface layer 111 and the back layer 113 each include an antistatic agent. The thickness of the surface layer 111 is less than 10 microns.

Description

Sheets for workpiece processing

The present invention relates to a workpiece processing sheet used for processing workpieces such as semiconductor wafers.

Semiconductor wafers such as silicon and gallium arsenide, and various packages are manufactured in a large-diameter state. After the wafer is cut (dicing, dicing) and peeled (picking up), it is moved to the next step. installation steps. At this time, a workpiece such as a semiconductor wafer is laminated on an adhesive sheet (hereinafter, sometimes referred to as a "workpiece processing sheet") provided with a base material and an adhesive layer, and undergoes back grinding, dicing, Processing such as washing, drying, expanding, picking up crystals, and mounting.

As a specific method of the above-mentioned dicing, in terms of general full cut dicing, a workpiece is cut by a rotating circular knife (cutting edge). At this time, in order to reliably cut the workpiece laminated on the workpiece processing sheet, not only the workpiece but also the adhesive layer are usually cut, and a part of the base material is also cut. At this time, chips from the materials constituting the adhesive layer and the base material are generated from chips for workpiece processing, and wafers obtained by cutting the workpiece may be contaminated by the chip chips. As one of the typical forms of the chip, there is a filament-shaped chip on the dicing line or near the cross section of the wafer separated by dicing.

Once the above-mentioned filament-shaped chip chips are attached in a large amount, wire bonding is hindered. Furthermore, if the chip is packaged in this way, the filament-shaped chip chips attached to the chip are decomposed by the heat of the package. This thermally decomposed product destroys the package and becomes a cause of failure in the obtained device. Since the filamentous cutting pieces are difficult to remove by washing, the yield of the cutting step is significantly reduced due to the occurrence of the filamentous cutting pieces. Therefore, when dicing is performed using a workpiece processing sheet, it is required to prevent the occurrence of filamentous cutting chips.

In addition, the sheet for workpiece processing is peeled from the adherend when a specific processing step is completed. At this time, an electrostatic force called peeling static electricity is generated between the sheet for workpiece processing and the adherend. Such electrostatic force causes dust and the like to adhere to workpieces and devices, and at the same time causes damage to workpieces and the like. Therefore, antistatic properties are also required for workpiece processing sheets.

In Patent Document 1, a specific antistatic agent, a specific polyolefin-based resin, and a specific rubber elastomer (elastomer) are disclosed for the purpose of providing a workpiece processing sheet with an excellent cutting chip suppression effect and antistatic properties. ), a base material prepared in a specific blending ratio. [Prior Art Literature] [Patent Document]

Patent Document 1: Japanese Patent No. 5056112

[Problem to be solved by the invention]

Incidentally, after the dicing step of the semiconductor wafer, cleaning of the resulting wafer is generally performed. Specifically, a workpiece processing sheet on which a plurality of wafers are placed is adsorbed and fixed on a spinner table, and the wafer is cleaned with ultrapure water on the workpiece processing sheet, and then dried ( air dry). The inventors have confirmed that peeling static electricity is also generated when the workpiece processing sheet on which a plurality of wafers are placed is pulled off the cleaning tray after such processing is completed.

In consideration of the above-mentioned stripping of static electricity, conventional workpiece processing sheets such as Patent Document 1 do not achieve a cutting chip suppression effect and antistatic properties at a high level.

The present invention has been made in view of these circumstances, and an object of the present invention is to provide a sheet for workpiece processing that can suppress the generation of chips well while exhibiting excellent antistatic properties. [means used to solve a problem]

In order to achieve the above object, firstly, the present invention provides a sheet for workpiece processing, comprising: a base material, and an adhesive layer laminated on one side of the base material, wherein the base material is characterized in that the base material has: The surface layer of the above-mentioned adhesive layer is located on the back layer relatively far away from the above-mentioned adhesive layer, and the intermediate layer is located between the above-mentioned surface layer and the above-mentioned back layer, and the above-mentioned surface layer and the above-mentioned back layer respectively contain antistatic agents , the thickness of the surface layer is 10 μm or less (Invention 1).

In the workpiece processing sheet related to the above-mentioned invention (Invention 1), the substrate is provided with the above-mentioned three layers, and the surface layer and the back layer contain antistatic agents respectively, and the thickness of the surface layer is within the above-mentioned range. Exhibits excellent antistatic properties and suppresses chips well.

In the above invention (Invention 1), the surface resistivity of the surface of the adhesive layer opposite to the substrate is preferably 1.0×10 ¹³ Ω/□ or less (Invention 2).

In the above-mentioned inventions (Inventions 1 and 2), the above-mentioned intermediate layer does not contain the above-mentioned antistatic agent, or the above-mentioned intermediate layer has a lower content (unit: mass %) than that of the above-mentioned surface layer and the above-mentioned back layer. ), it is better to contain the above-mentioned antistatic agent (invention 3).

In the above inventions (Inventions 1 to 3), the antistatic agent is preferably a polymer antistatic agent (Invention 4).

In the above inventions (Inventions 1 to 4), the thickness of the intermediate layer is preferably not less than 40 μm and not more than 75 μm (Invention 5).

In the above invention (Invention 1), the thickness of the back layer is preferably not less than 2 μm and not more than 40 μm (Invention 6).

Among the above inventions (Inventions 1 to 6), a cut sheet is preferable (Invention 7). [Efficacy of the invention]

The workpiece processing sheet according to the present invention exhibits excellent antistatic properties and can suppress the occurrence of chipping well.

[Mode for Carrying Out the Invention]

Embodiments of the present invention will be described below. FIG. 1 shows a cross-sectional view of a workpiece processing sheet according to an embodiment. The workpiece processing sheet 1 shown in FIG. 1 includes a base material 11 and an adhesive layer 12 laminated on one side of the base material 11 .

As shown in Figure 1, the above-mentioned substrate 11 has: a surface layer 111 located relatively close to the adhesive layer 12, a back layer 113 located relatively far away from the adhesive layer 12, and a surface layer 113 located between the surface layer 111 and the back layer 113. The intermediate layer 112 in between.

Then, the surface layer 111 and the back layer 113 each contain an antistatic agent. Thus, the workpiece processing sheet 1 according to the present embodiment has excellent antistatic properties. Therefore, it is possible to favorably suppress the peeling static electricity when separating the peeling sheet and the workpiece from the sheet 1 for workpiece processing. Furthermore, even after washing and drying the workpiece on the workpiece processing sheet 1 , peeling static electricity when the workpiece processing sheet 1 is pulled away from the cleaning tray is favorably prevented.

In addition, the thickness of the surface layer 111 in this embodiment is 10 micrometers or less. In this way, when the thickness of the surface layer 111 located relatively close to the adhesive layer 12 is 10 μm or less, when the workpiece processing sheet according to this embodiment is used for dicing, the generation of cutting chips can be well suppressed. The inventors found that a layer containing an antistatic agent is more likely to generate chips than a layer not containing an antistatic agent. In the workpiece processing sheet 1 according to the present embodiment, since the surface layer 111 containing an antistatic agent has a thickness of 10 μm or less, even if desired antistatic properties are exhibited, generation of chips can be well suppressed at the same time.

The thickness of the surface layer 111 is preferably 8 μm or less, particularly preferably 4 μm or less, from the viewpoint of more effectively suppressing the occurrence of chips. In addition, from the viewpoint of being easy to have better antistatic properties, the thickness of the surface layer 111 is preferably 1 μm or more, particularly preferably 2 μm or more.

1. Composition of sheet for workpiece processing (1) Substrate The base material 11 in this embodiment includes the surface layer 111 , the intermediate layer 112 , and the back layer 113 as described above. The composition of these layers is not particularly limited as long as the surface layer 111 and the back layer 113 each contain an antistatic agent.

Here, although the intermediate layer 112 may also contain an antistatic agent, from the viewpoint of easily suppressing the occurrence of chipping, the intermediate layer 112 does not contain an antistatic agent, or the intermediate layer 112 is less than the surface layer 111. And the back layer 113 preferably contains an antistatic agent in a smaller amount (unit: mass %). In this way, by not containing an antistatic agent, or the middle layer 112 with a small content exists between the surface layer 111 and the back layer 113, at the moment of cutting, when the cutting edge reaches the middle layer 112, it can be well The occurrence of chipping from the intermediate layer 112 is suppressed.

Materials other than the antistatic agent in each layer constituting the base material 11 are not particularly limited as long as they can form such layers, and for example, resins can be used. It is preferable to use at least one of a polyolefin-based resin and a thermoplastic elastomer from the viewpoint of ease of suppressing chipping.

In addition, the composition of the surface layer and the back layer may be different, or all may be the same composition.

(1-1) Antistatic agent The antistatic agent in this embodiment is not particularly limited, and known ones can be used. As examples of antistatic agents, although low molecular type antistatic agents, high molecular type antistatic agents, etc. can be cited, it is easy to suppress the generation of chipping, or from the bleed (bleed) from the surface layer 111 and back layer 113. From the point of view that out) is difficult to occur, it is better to use a polymer antistatic agent.

Examples of high-molecular antistatic agents include polyether ester amide, polyether polyolefin block copolymers, and copolymers having polyether units. Alkali metal salts and alkaline earth compounds may also be contained in these copolymers. Metal salts such as metal salts, and ionic liquids.

The content of the antistatic agent in the surface layer 111 is preferably at least 3% by mass, particularly preferably at least 5% by mass, and more preferably at least 10% by mass. When content of an antistatic agent is 3 mass % or more, it becomes easy to exhibit favorable antistatic property. In addition, the content of the antistatic agent in the surface layer 111 is preferably not more than 40% by mass, particularly preferably not more than 35% by mass, and more preferably not more than 30% by mass. When content of an antistatic agent is 40 mass % or less, generation|occurrence|production of chipping becomes easy to suppress.

The content of the antistatic agent in the back layer 113 is preferably at least 10% by mass, particularly preferably at least 20% by mass, and more preferably at least 30% by mass. When content of an antistatic agent is 10 mass % or more, it becomes easy to exhibit favorable antistatic property. In addition, the content of the antistatic agent in the back layer 113 is preferably not more than 50% by mass, particularly preferably not more than 45% by mass, and more preferably not more than 40% by mass. When the content of the antistatic agent is 50% by mass or less, it becomes easy to control the occurrence of chipping.

And, as mentioned above, it is better that the middle layer 112 does not contain an antistatic agent, or that the middle layer 112 contains an antistatic agent in a lower content (unit: mass %) than the surface layer 111 and the back layer 113 respectively. . When the intermediate layer 112 contains an antistatic agent, the content of the antistatic agent in the intermediate layer 112 is preferably not more than 10% by mass, particularly preferably not more than 5% by mass, and more preferably not more than 3% by mass. When the content of the antistatic agent in the intermediate layer 112 is 5% by mass or less, it becomes easy to suppress the occurrence of chips. In addition, the lower limit of the content may be, for example, 0.01% by mass or more.

(1-2) Polyolefin resin Specific examples of the polyolefin-based resin are not particularly limited. In addition, in this specification, the so-called polyolefin-based resin refers to a polymer or copolymer using olefin as a monomer, or a copolymer of olefin and a molecule other than olefin as a monomer. A resin having a mass ratio of 1.0% by mass or more based on olefin units.

The polymer constituting the polyolefin-based resin may be linear or may have a side chain. In addition, the polymer may have an aromatic ring or an aliphatic ring.

Examples of the olefin monomer constituting the polyolefin resin include olefin monomers having 2 to 8 carbon atoms, α-olefin monomers having 3 to 18 carbon atoms, and olefin monomers having a cyclic structure. Examples of the olefin monomer having 2 to 8 carbon atoms include ethylene, propylene, 2-butene, octene and the like. Examples of α-olefin monomers having 3 to 18 carbon atoms include propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-decene, 1- Dodecene, 1-tetradecene, 1-octadecene, etc. Examples of the olefin monomer having a cyclic structure include norcamphene, cyclopentadiene, cyclohexadiene, dicyclopentadiene, tetracyclododecene, and derivatives thereof.

The polyolefin-based resins may be used alone or in combination of two or more.

Among the specific examples of the above-mentioned polyolefin-based resin, it is preferable to use at least one of polyethylene containing ethylene as a main polymerized unit and polypropylene containing propylene as a main polymerized unit.

As the aforementioned polypropylene, for example, homo polypropylene, random polypropylene, and block polypropylene are preferably used. These can be used individually by 1 type or in mixture of 2 or more types. In particular, it is preferable to use mixed homopolypropylene and random polypropylene.

As the above-mentioned homopolypropylene, random polypropylene, and block polypropylene, commercially available items can be used, respectively. As examples of commercially available products of homopolymer polypropylene, all of them are manufactured by Prime Polymer Co., Ltd. under the trade name "Prime Polypro E111G", the trade name "Prime Polypro E-100GV", the trade name "Prime Polypro E-100GV", the trade name "Prime Polypro E- -100GPL", trade name "Prime Polypro E-200GP", etc. Examples of commercially available products of random polypropylene include trade names "Prime Polypro B221WA", trade names "Prime Polypro B241", trade names "Prime Polypro E222", trade names "Prime Polypro E222" and Name "Prime Polypro E-333GV" and so on. Examples of commercially available block polypropylene products include "Prime Polypro E701G", "Prime Polypro E702G", and "Prime Polypro E702MG", all manufactured by Prime Polymer Co., Ltd. .

The above-mentioned polyethylene may be any one of high-density polyethylene, medium-density polyethylene, low-density polyethylene, ultra-low-density polyethylene, and linear low-density polyethylene, or a mixture of two or more thereof. .

In particular, it is preferable to use low-density polyethylene as the above-mentioned polyethylene, and examples of commercially available products include "Novatec LL" manufactured by Mitsubishi Chemical Corporation, and NEO manufactured by Prime Polymer Co., Ltd. -ZEX series, ULTZEX series, etc.

When any one of the layers constituting the base material 11 contains a polyolefin resin, the content of the polyolefin resin in the layer is preferably at least 10% by mass, particularly preferably at least 15% by mass, and further preferably at least 20% by mass. More than % is better. In addition, the above-mentioned content is preferably at most 100% by mass, particularly preferably at most 95% by mass, and further preferably at most 90% by mass. When the content of the polyolefin-based resin is in the above-mentioned range, the workpiece processing sheet 1 according to the present embodiment becomes easy to obtain a better cutting chip suppressing effect.

(1-3) Thermoplastic elastomer The above-mentioned thermoplastic elastomer may be any other than the above-mentioned polyolefin-based resin, and it is not particularly limited as long as it can form the base material 11 . Examples of thermoplastic elastomers include olefin-based elastomers, rubber elastomers, urethane-based elastomers, styrene-based elastomers, acrylic-based elastomers, and vinyl chloride-based elastomers. These may be used individually or in combination of 2 or more types.

Among the above-mentioned elastomers, olefin-based elastomers are preferable from the viewpoint of being easy to obtain a good chipping suppressing effect. In addition, in this specification, the term "olefin-based elastomer" refers to a copolymer containing structural units derived from olefins or derivatives thereof (olefin-based compounds), and has rubber-like elasticity in a temperature range including normal temperature, Also thermoplastic material.

As an example of olefinic elastomers, can be cited, including at least one selected from ethylene. Propylene copolymer, ethylene. α-olefin copolymer, propylene. α-olefin copolymer, butene. α-olefin copolymer, ethylene. Propylene. α-olefin copolymer, ethylene. Butene. α-olefin copolymer, propylene. Butene. α-olefin copolymers and ethylene. Propylene. Butene. A group of resins consisting of α-olefin copolymers. Among these, ethylene. Propylene copolymers are preferred.

When any one of the layers constituting the base material 11 contains a thermoplastic elastomer, the content of the thermoplastic elastomer in the layer is preferably at least 1% by mass, particularly preferably at least 10% by mass, and further preferably at least 15% by mass. More than % is better. In addition, the above content is preferably at most 90% by mass, particularly preferably at most 80% by mass, further preferably at most 70% by mass. When the content of the thermoplastic elastomer is in the above-mentioned range, the workpiece machining sheet 1 according to the present embodiment can easily obtain a better cutting chip suppression effect.

Moreover, although the layer constituting the base material 11 may contain a styrene-based elastomer as a thermoplastic elastomer, from the viewpoint of being easy to obtain a better cutting chip suppression effect, the less the content, the better. The layer of the substrate 11 preferably does not substantially contain a styrene-based elastomer. In addition, in this specification, the term "styrene-based elastomer" refers to a copolymer containing structural units derived from styrene or its derivatives (styrene-based compounds), and has a rubber-like texture in a region including normal temperature. elastic and thermoplastic material.

When the layer constituting the base material 11 contains a styrene-based elastomer, the content thereof is preferably less than 10% by mass, particularly preferably not more than 5% by mass, further preferably not more than 1% by mass. In addition, the above-mentioned case where the styrene-based elastomer is not substantially contained specifically means that the content of the styrene-based elastomer in the layer constituting the base material 11 is 0.2% by mass or less.

(1-4) Other ingredients The layer constituting the base material 11 may contain other components than the above-mentioned antistatic agent, polyolefin-based resin, and thermoplastic elastomer. In particular, the resin composition may contain components usable as base materials of sheets for general workpiece processing.

Examples of such components include various additives such as flame retardants, plasticizers, lubricants, antioxidants, colorants, infrared absorbers, ultraviolet absorbers, and ion scavengers. The content of these additives is not particularly limited, but is preferably within a range in which the base material can exhibit desired functions.

(1-5) Surface treatment of substrate On the surface of the substrate 11 on which the adhesive layer 12 is laminated, in order to improve the adhesion with the adhesive layer 12, primer treatment, corona treatment, plasma treatment, and roughening treatment (blunt surface treatment) may also be performed. ) and other surface treatment. As the roughening treatment, for example, an embossing method, a blasting method, and the like can be mentioned. Among them, corona treatment is preferable.

(1-6) Manufacturing method of base material The manufacturing method of the substrate 11 in this embodiment is not particularly limited, for example, melt extrusion methods such as T-die method and circular die method; calendering method; solution methods such as dry method and wet method, etc. can be used. Among them, from the viewpoint of efficiently producing the base material, it is preferable to employ the melt extrusion method, and it is particularly preferable to employ the T-die method.

In addition, when the base material 11 is manufactured by the melt extrusion method, the components constituting each layer are kneaded separately, and the obtained kneaded product is directly or temporarily manufactured into a pellet, and a known extruder is used to simultaneously extrude Multiple layers are used for film formation.

(1-7) Physical properties of the base material, etc. The surface resistivity of the surface layer 111 side of the base material 11 is preferably 1.0×10 ¹³ Ω/□ or less, especially 1.0×10 ¹² Ω/□ or less. Good, more preferably 1.0×10 ¹¹ Ω/□ or less. Since the above-mentioned surface resistivity is 1.0×10 ¹³ Ω/□ or less, the workpiece processing sheet 1 according to the present embodiment tends to have good antistatic properties. In addition, the lower limit of the surface resistivity is not particularly limited, for example, it may be 1.0×10 ⁸ Ω/□ or more, particularly 1.0×10 ⁹ Ω/□ or more. The details of the method for measuring the above-mentioned surface resistivity are as described in the following test examples.

The thickness of the intermediate layer 112 in this embodiment is preferably at least 40 μm, particularly preferably at least 50 μm, and further preferably at least 60 μm. When the thickness of the intermediate layer 112 is 40 μm or more, it becomes easy to suppress the occurrence of chips. In addition, the workpiece processing sheet 1 tends to have an appropriate strength, and it becomes easy to favorably support the workpiece fixed to the workpiece processing sheet 1 . The thickness of the intermediate layer 112 is preferably not more than 100 μm, particularly preferably not more than 90 μm, further preferably not more than 80 μm. When the thickness of the intermediate layer 112 is 100 μm or less, the thickness of the workpiece processing sheet 1 has good flexibility, for example, it becomes easy to stretch well.

The thickness of the back layer 113 in this embodiment is preferably at least 2 μm, particularly preferably at least 4 μm, and further preferably at least 8 μm. When the thickness of the back layer 113 is 2 μm or more, the workpiece processing sheet 1 tends to have good antistatic properties. In addition, the thickness of the back layer 113 is preferably 40 μm or less, particularly preferably 30 μm or less, further preferably 25 μm or less. When the thickness of the back surface layer 112 is 40 μm or less, the thickness of the workpiece processing sheet 1 has good flexibility, for example, it becomes easy to stretch well.

(2) Adhesive layer As the adhesive constituting the adhesive layer 12 in this embodiment, as long as it can exert sufficient adhesive force to the adhered object (in particular, it becomes sufficient adhesive force to the workpiece as for processing the workpiece), there is no particular limitation. limited. Examples of the adhesive constituting the adhesive layer 12 include acrylic adhesives, rubber adhesives, silicone adhesives, urethane adhesives, polyester adhesives, and polyvinyl ether adhesives. . Among these, it is preferable to use an acrylic adhesive from the viewpoint of easily exhibiting a desired adhesive force.

The adhesive constituting the adhesive layer 12 in this embodiment may not be an adhesive that is curable by active energy rays, but an adhesive that is curable by active energy rays (hereinafter, sometimes referred to as "active energy ray Hardening adhesive") is preferred. Since the adhesive layer 12 is composed of an active energy ray-curable adhesive, the adhesive layer 12 is hardened by irradiation of active energy rays, and the adhesive force of the sheet 1 for workpiece processing to an adherend can be easily reduced. In particular, the processed workpiece can be easily separated from the workpiece processing sheet 1 by irradiation of active energy rays.

The active energy ray-curable adhesive constituting the adhesive layer 12 may be an active energy ray-curable polymer as a main component, or may be an active energy ray non-curable polymer (having no active energy). line-curable polymer) and a mixture of monomers and/or oligomers having at least one active energy ray-curable group as the main component. In addition, the active energy ray-curable adhesive may be a mixture of an active energy ray-curable polymer and a monomer and/or oligomer having at least one active energy ray-curable group.

The aforementioned active energy ray curable polymer is a (meth)acrylate polymer (hereinafter, sometimes referred to as "Active energy ray-curable polymer") is preferable. The active energy ray curable polymer is preferably obtained by reacting an acrylic polymer having a functional group-containing monomer unit with an unsaturated group-containing compound having a functional group bonded to the functional group. In addition, in this specification, (meth)acrylic acid means both acrylic acid and methacrylic acid. The same applies to other similar terms. In addition, "polymer" is a concept which also includes a "copolymer".

The above-mentioned acrylic polymer having a functional group-containing monomer unit may be a functional group-containing monomer polymerized with another monomer. As such functional group-containing monomers and other monomers, as well as the above-mentioned unsaturated group-containing compounds, known ones can be used, for example, those disclosed in International Publication No. 2018/084021 can be used.

The weight average molecular weight of the active energy ray-curable polymer is preferably at least 10,000, particularly preferably at least 150,000, and further preferably at least 200,000. In addition, the weight average molecular weight is preferably at most 1,500,000, especially preferably at most 1,000,000. In addition, the weight average molecular weight (Mw) in this specification is the value of conversion standard polystyrene measured by the gel permeation chromatography (GPC method).

As the above-mentioned active energy ray non-hardening polymer component, for example, the above-mentioned acrylic polymer before the unsaturated group-containing compound is reacted can be used.

The weight average molecular weight of the acrylic polymer as the active energy ray non-curable polymer component is preferably at least 10,000, particularly preferably at least 150,000, and further preferably at least 200,000. In addition, the weight average molecular weight is preferably at most 1,500,000, especially preferably at most 1,000,000.

In addition, as the above-mentioned monomer and/or oligomer having at least one active energy ray-curable group, for example, an ester of a polyhydric alcohol and (meth)acrylic acid or the like can be used.

Furthermore, when ultraviolet rays are used as the active energy rays for curing the active energy ray-curable adhesive, it is preferable to add a photopolymerization initiator to the adhesive. In addition, an active energy ray non-hardening polymer component or oligomer component, a crosslinking agent, and the like may be added to the adhesive.

The thickness of the adhesive layer 12 in this embodiment is preferably at least 1 μm, particularly preferably at least 3 μm, and further preferably at least 5 μm. In addition, the thickness of the adhesive layer 12 is preferably 70 μm or less, particularly preferably 30 μm or less, further preferably 15 μm or less. When the thickness of the adhesive layer 12 is within the above-mentioned range, the sheet 1 for workpiece processing according to this embodiment becomes easy to exhibit desired adhesiveness.

(3) Peeling sheet The sheet 1 for workpiece processing according to this embodiment may protect the surface of the adhesive layer 12 opposite to the substrate 11 (hereinafter, sometimes referred to as "adhesive surface") until it is attached to the workpiece. For the purpose, layer the release sheet on the surface.

The structure of the above-mentioned release sheet is optional, and an example is one in which a plastic film is peeled with a release agent or the like. Specific examples of the plastic film include polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, and polyester films such as polypropylene and polyethylene. Polyolefin film. As the above-mentioned release agent, silicone-based, fluorine-based, long-chain alkyl-based, etc. can be used, and among them, silicone-based, which is inexpensive and can obtain stable performance, is preferable.

The thickness of the release sheet is not particularly limited, and may be, for example, not less than 16 μm and not more than 250 μm.

(4) Others In the workpiece processing sheet 1 according to this embodiment, an adhesive layer may be formed on the surface of the adhesive layer 12 opposite to the substrate 11 . At this time, the sheet 1 for workpiece processing related to this embodiment can be used as a cutting. Die-bonding sheets are used. In this sheet, a workpiece is attached to the surface of the adhesive layer opposite to the adhesive layer 12, and the workpiece and the adhesive layer are cut to obtain a wafer on which the adhesive layer is laminated into individual pieces. The chip is easily fixed on the object on which the chip is mounted by the adhesive layer that has been separated into pieces. As the material constituting the adhesive layer, those containing thermoplastic resin and low-molecular-weight thermosetting adhesive components, those containing B-stage (semi-cured) thermosetting adhesive components, etc. are preferably used.

In addition, in the workpiece processing sheet 1 according to this embodiment, a protective film forming layer may be formed on the adhesive surface of the adhesive layer 12 . In this case, the workpiece processing sheet 1 according to this embodiment can be used as a protective film forming and dicing sheet. In this type of sheet, by attaching a workpiece on the surface of the protective film forming layer opposite to the adhesive layer 12, and cutting the workpiece together with the protective film forming layer, individualized wafers on which the protective film forming layer is laminated can be obtained. . As the workpiece, it is preferable to use one in which a circuit is formed on one surface. In this case, a protective film forming layer is usually deposited on the surface opposite to the surface on which the circuit is formed. By curing the individualized protective film formation layer at a specific timing, a protective film having sufficient durability can be formed on the wafer. The protective film forming layer is preferably formed of an uncured curable adhesive.

2. Physical properties of workpiece processing sheet In the workpiece processing sheet 1 according to this embodiment, the surface resistivity of the surface (adhesive surface) of the adhesive layer 12 on the opposite side to the base material 11 before ultraviolet irradiation is expressed as 1.0×10 ¹³ It is preferably Ω/□ or less, particularly preferably 1.0×10 ¹² Ω/□ or less, further preferably 1.0×10 ¹¹ Ω/□ or less. Since the above-mentioned surface resistivity is 1.0×10 ¹³ Ω/□ or less, the workpiece processing sheet 1 according to the present embodiment tends to have good antistatic properties. In addition, the lower limit of the surface resistivity is not particularly limited, for example, it may be 1.0×10 ⁸ Ω/□ or more, particularly 1.0×10 ⁹ Ω/□ or more. The details of the method for measuring the surface resistivity are as described in the following test examples.

3. Manufacturing method of sheet for workpiece processing The method of manufacturing the workpiece processing sheet 1 according to this embodiment is not particularly limited. For example, after forming the adhesive layer 12 on the release sheet, it is preferable that the sheet 1 for workpiece processing can be obtained on one surface of the build-up layer substrate 11 on the side opposite to the release sheet in the adhesive layer 12 .

Formation of the above-mentioned adhesive layer 12 can be performed by a known method. For example, an adhesive composition for forming the adhesive layer 12 and, if necessary, a coating liquid containing a solvent or a dispersion medium are prepared. Then, the above-mentioned coating liquid is applied to the releasable surface of the release sheet (hereinafter, sometimes referred to as "release surface"). Next, the adhesive layer 12 can be formed by drying the obtained coating film.

Coating of the above-mentioned coating liquid can be carried out by a known method, for example, by rod coating method, knife coating method, roll coating method, blade coating method, die coating method, gravure coating method, etc. Buffalo and so on. Furthermore, the properties of the coating liquid are not particularly limited as long as it can be applied, and the components for forming the adhesive layer 12 may be contained as solutes or dispersoids. In addition, the release sheet can also be used as a process material for peeling, and can also protect the adhesive layer 12 during the period of sticking to the adhered object.

When the adhesive composition used to form the adhesive layer 12 contains the above-mentioned crosslinking agent, by changing the above-mentioned drying conditions (temperature, time, etc.), or by additionally providing heat treatment, the polymer in the coating film It is preferable that the component and the crosslinking agent undergo a crosslinking reaction to form a crosslinked structure with a desired density in the adhesive layer 12 . Moreover, in order to make the above-mentioned cross-linking reaction fully proceed, after the adhesive layer 12 and the substrate 11 are pasted together, for example, the so-called ripening can also be carried out at 23° C. and in an environment with a relative humidity of 50% for several days. .

4. How to use the sheet for workpiece processing The workpiece processing sheet 1 according to this embodiment can be used for processing workpieces such as semiconductor wafers. In other words, after the adhesive surface of the workpiece processing sheet 1 according to this embodiment is attached to the workpiece, the workpiece can be processed on the workpiece processing sheet 1 . For this processing, the workpiece processing sheet 1 according to this embodiment is used as a back grinding sheet, a dicing sheet, a stretching sheet, a wafer pickup, and the like. Here, examples of the workpiece include semiconductor members such as semiconductor wafers and semiconductor packages, and glass members such as glass plates.

The workpiece machining sheet 1 according to the present embodiment can satisfactorily suppress the occurrence of cutting chips, particularly filamentous cutting chips, when used for cutting using a rotating shot blade as described above. Therefore, the workpiece processing sheet 1 according to the present embodiment is particularly suitable for use as a dicing sheet among the above-mentioned workpiece processing sheets.

Furthermore, the workpiece processing sheet 1 according to this embodiment has excellent antistatic properties as described above. The workpiece processing sheet 1 according to this embodiment can suppress the peeling static electricity when separating the peeling sheet and separating the workpiece. Furthermore, in the workpiece processing sheet 1 related to this embodiment, the peeling static electricity when the workpiece processing sheet is pulled away from the cleaning tray after washing and drying the wafer with the workpiece processing sheet in a fixed state on the cleaning tray can also be effectively suppressed. Therefore, the workpiece processing sheet 1 related to this embodiment is also suitable for this type of cleaning. dry.

And, when the sheet 1 for workpiece processing related to this embodiment is equipped with the above-mentioned adhesive layer, the sheet 1 for workpiece processing can be used as a cutter. Die-bonding sheets are used. Furthermore, when the workpiece processing sheet 1 according to this embodiment is provided with the above-mentioned protective film forming layer, the workpiece processing sheet 1 can be used as a protective film forming and dicing sheet.

In addition, when the adhesive layer 12 in the workpiece processing sheet 1 according to this embodiment is composed of the above-mentioned active energy ray-curable adhesive, it is preferable to irradiate the subsequent active energy ray at the time of use. In other words, when the workpiece is processed on the workpiece processing sheet 1 and the processed workpiece is separated from the workpiece processing sheet 1, it is preferable to irradiate the adhesive layer 12 with active energy rays before the separation. In this way, the adhesive layer 12 hardens, and the adhesive force of the adhesive sheet to the workpiece after processing is reduced favorably, and the separation of the workpiece after processing becomes easy.

The embodiments described above are described for the understanding of the present invention, and are not intended to limit the present invention. Therefore, each element disclosed in the above embodiment is intended to include all design changes and equivalents within the technical scope of the present invention.

For example, another layer may be laminated between the substrate 11 and the adhesive layer 12 in the workpiece processing sheet 1 according to this embodiment, or on the surface of the substrate 11 opposite to the adhesive layer 12 . In addition, on the surface opposite to the intermediate layer 112 in the surface layer 111, between the surface layer 111 and the intermediate layer 112, between the intermediate layer 112 and the back layer 113, and the surface on the opposite side to the intermediate layer 112 in the back layer 113, Other layers may be laminated separately. [Example]

Hereinafter, although an Example etc. demonstrate this invention more concretely, the scope of the present invention is not limited to these Examples etc.

[Example 1] (1) Preparation of base material 36 parts by mass of random polypropylene resin (manufactured by Japan Polypropylene Corporation, trade name "Novatec FX3B"), 59 parts by mass of olefin-based thermoplastic elastomer (manufactured by Japan Polypropylene Corporation, trade name "WELNEX RFX4V"), and antistatic agent ( Sanyo Chemical Co., Ltd., trade name "PELECTRON PVL") 5 parts by mass were dried separately, and mixed by a biaxial mixer to obtain pellets for the surface layer and the back layer.

In addition, 38 parts by mass of a random polypropylene resin (manufactured by Japan Polypropylene Corporation, trade name "Novatec FX3B") and 62 parts by mass of an olefin-based thermoplastic elastomer (manufactured by Japan Polypropylene Corporation, trade name "WELNEX RFX4V") were mixed to make After each drying, the pellets for the intermediate layer were obtained by mixing with a twin-shaft mixer.

Using the two types of ingots obtained above, coextrusion molding was carried out with a small T-die extruder (manufactured by Toyo Seiki Seisakusho Co., Ltd., trade name "LABO PLASTOMILL") to obtain a sequentially laminated layer with a thickness of 4 μm. A base material with a three-layer structure consisting of a surface layer, an intermediate layer with a thickness of 72 μm, and a back layer with a thickness of 4 μm.

(2) Preparation of adhesive composition 62 parts by mass of n-butyl acrylate, 10 parts by mass of methyl methacrylate, and 28 parts by mass of 2-hydroxyethyl acrylate were polymerized by a solution polymerization method to obtain a (meth)acrylate polymer. Next, 2-methacryloyloxyethyl isocyanate (MOI) was added in an amount corresponding to 80 mole % of 2-hydroxyethyl acrylate constituting the (meth)acrylate polymer. At the same time, dibutyltin dilaurate (DBTDL), which is a tin-containing catalyst, was added in an amount of 0.13 parts by mass relative to 100 parts by mass of the (meth)acrylate polymer. Then, by making it react at 50 degreeC for 24 hours, the (meth)acrylate polymer which introduced the active energy ray curable group into a side chain was obtained. The weight average molecular weight of this active energy ray curable polymer was measured by the following method, and it was 500,000.

100 parts by mass of the (meth)acrylate polymer obtained above having an active energy ray-curable group introduced into the side chain (in terms of solid content, the same applies hereinafter), 2-hydroxyl-1-{ 4-[4-(2-Hydroxy-2-methyl-propionyl)-benzyl]phenyl}-2-methyl-propan-1-one (manufactured by BASF, trade name "Omnirad 127") 2 parts by mass and 1 part by mass of trimethylolpropane-modified toluene diisocyanate (manufactured by Tosoh Co., Ltd., trade name "Coronate L") as a crosslinking agent were mixed in a solvent to obtain an adhesive composition Coating solution for objects.

(3) Formation of adhesive layer On the release surface of a release sheet (manufactured by LINTEC Corporation, trade name "SP-PET381031") formed by a silicone-based release agent layer on one side of a polyethylene terephthalate film with a thickness of 38 μm, coat The coating solution of the adhesive composition obtained in the above step (2) was spread and dried by heating to obtain a laminate in which an adhesive layer with a thickness of 5 μm was formed on the release sheet.

(4) Production of adhesive sheets After performing corona treatment on the surface layer side surface of the base material obtained in the above step (1), the corona treated surface and the adhesive layer side surface of the laminate obtained in the above step (3) Bonded to obtain a sheet for workpiece processing.

Here, the said weight average molecular weight (Mw) is the weight average molecular weight of the conversion standard polystyrene measured (GPC measurement) using the gel permeation chromatography (GPC) under the following conditions. ＜Measurement conditions＞ ． Measuring device: Tosoh Co., Ltd., HLC-8320 ． GPC column (pass through in the following order): manufactured by Tosoh Co., Ltd. TSK gel super H-H TSK gel super HM-H TSK gel super H2000 ． Determination of solvent: tetrahydrofuran ． Measuring temperature: 40°C

[Examples 2-6, Comparative Examples 1-2] Sheets for workpiece processing were obtained in the same manner as in Example 1, except that the composition of the ingot forming each layer of the base material and the thickness of each layer were changed as described in Table 1.

[Test Example 1] (Measurement of Surface Resistivity) For the substrates produced in Examples and Comparative Examples, after humidity control for 24 hours at 23°C and 50% relative humidity, the surface resistivity of the surface on the surface layer side was measured using a DIGITAL ELECTROMETER (manufactured by ADVANTEST) at an applied voltage of 100V. To measure. The results are shown in Table 2.

In addition, the pieces for workpiece processing manufactured in the examples and comparative examples were cut into 100 mm×100 mm, and this was used as a sample for surface resistivity measurement. The surface resistivity of the sample for measuring the surface resistivity was controlled at 23°C and 50% relative humidity for 24 hours, and then the peeling sheet was peeled off, and the surface resistivity of the exposed side of the adhesive layer (adhesive surface) was the same as above. To measure. The results are also shown in Table 2.

[Test Example 2] (Evaluation of Chip Suppression Effect) After the release sheet was peeled off from the workpiece processing sheets manufactured in Examples and Comparative Examples, the exposed surface of the exposed adhesive layer was attached to a 6 inch silicon wafer. Next, a ring frame for dicing is attached to the periphery of the above-mentioned exposed surface of the workpiece processing sheet (position not overlapping the silicon wafer). Furthermore, the workpiece processing sheet is cut in accordance with the outer diameter of the ring frame.

Subsequently, by using a dicing device (manufactured by Disco Corporation, trade name "DFD6362"), dicing was performed under the following dicing conditions, and the silicon wafer was singulated into wafers having a size of 5 mm×5 mm. cutting conditions Wafer thickness: 150μm Blades: Z1 and Z2 below are made by Disco Corporation Z1: Product name "ZH05-SD3000-50DD" Z2: Product name "NBC-SD3000-50BB" Blade speed Z1: 55000rpm Z2: 45000rpm Cutting speed: 20mm/sec blade height Z1: 0.135mm Z2: 0.065mm Cutting water volume: 1.0L/min Cutting water temperature: 25°C

After dicing, the surface of the obtained wafer was observed with an electron microscope (manufactured by KEYENCE, trade name "VHZ-100", magnification: 300 times), and the number of diced pieces was counted. Specifically, the number of chips present on the dicing line per one wafer is counted. Then, the chips suppressing effect was evaluated according to the following criteria. Table 2 shows the number of chips and evaluation results. ⊚: The number of chips is 3 or less. ◯: The number of chips is more than 3 and 10 or less. ×: The number of chips exceeds 10.

[Test Example 3] (Evaluation of Antistatic Property) Using a grinder (manufactured by Disco Corporation, trade name "DFG8540"), one side of a 6-inch silicon wafer was ground to a thickness of 350 μm. The exposed surface of the adhesive layer which peeled off the peeling sheet from the sheet|seat for workpiece processing manufactured in the Example and the comparative example was affixed to this polished surface using a bonding machine.

After 20 minutes from the attachment, the silicon wafer was singulated into chips by dicing under the following dicing conditions using a dicing device (manufactured by Disco Corporation, trade name "DFD6362"). cutting conditions Chip size: 10mm×10mm Cutting height: 60μm Blade: Product name "ZH05-SD2000-Z1-90 CC" Blade speed: 35000rpm Cutting speed: 60mm/sec Cutting water volume: 1.0L/min Cutting water temperature: 20°C

After dicing, the workpiece processing sheet is held in a fixed state by being adsorbed on the cleaning plate, and the wafer obtained as described above is cleaned and dried. Then, the electrostatic voltage (V) of the workpiece processing sheet immediately after the workpiece processing sheet was lifted from the cleaning tray was measured using a measuring device (manufactured by Prostat, trade name "PFK-100"). Then, antistatic property was evaluated according to the following criteria. Table 2 shows the static voltage and evaluation results. ⊚: Static voltage is 100 V or less. ○: The static voltage exceeds 100V and is 500V or less. ×: Static voltage exceeds 500V.

[Table 1] Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Comparative example 1 Comparative example 2 Thickness of each layer (surface layer/intermediate layer/back layer) (μm) 4/72/4 4/64/12 8/60/12 4/64/12 4/64/12 4/64/12 12/56/12 4/72/4 Composition (parts by mass) surface layer Polypropylene NOVATEC FX3B (manufactured by Japan Polypropylene Corporation) 36 36 36 34 32 32 36 38 Olefin-Based Thermoplastic Elastomers WELNEX RFX4V (manufactured by Japan Polypropylene Corporation) 59 59 59 56 53 53 59 62 antistatic agent PELECTRON PVL (manufactured by Sanyo Chemical Co., Ltd.) 5 5 5 10 15 - - - middle layer Polypropylene NOVATEC FX3B (manufactured by Japan Polypropylene Corporation) 38 38 38 38 38 38 38 38 Olefin-Based Thermoplastic Elastomers WELNEX RFX4V (manufactured by Japan Polypropylene Corporation) 62 62 62 62 62 62 62 62 back layer Polypropylene NOVATEC FX3B (manufactured by Japan Polypropylene Corporation) 36 36 36 34 32 32 36 38 Olefin-Based Thermoplastic Elastomers WELNEX RFX4V (manufactured by Japan Polypropylene Corporation) 59 59 59 56 53 53 59 62 antistatic agent PELECTRON PVL (manufactured by Sanyo Chemical Co., Ltd.) 5 5 5 10 15 - - - PELECTRON PVH (manufactured by Sanyo Chemical Co., Ltd.) - - - - - 15 5 -

[Table 2] Surface resistivity (Ω/□) Chip inhibition effect Antistatic The surface layer side of the substrate Adhesive surface number of lines Evaluation static voltage (V) Evaluation Example 1 3.7 × 10 ¹¹ 1.4 × 10 ¹² 0 ◎ 258 ○ Example 2 4.4 × 10 ¹¹ 5.2 × 10 ¹¹ 3 ◎ 160 ○ Example 3 2.3 × 10 ¹¹ 3.0 × 10 ¹¹ 8 ○ 51 ◎ Example 4 9.6 × 10 ¹⁰ 1.8 × 10 ¹¹ 1 ◎ 20 ◎ Example 5 4.5 × 10 ¹⁰ 7.3 × 10 ¹⁰ 4 ○ 18 ◎ Example 6 1.3 × 10 ¹¹ 1.6 × 10 ¹¹ 1 ◎ 17 ◎ Comparative example 1 1.9 × 10 ¹¹ 2.1 × 10 ¹¹ twenty three x 18 ◎ Comparative example 2 >10 ¹⁵ >10 ¹⁵ 0 ◎ >1000 x

As can be clearly seen from Table 2, the workpiece processing sheets produced in the examples exhibit excellent antistatic properties while suppressing chipping well. [Industrial Utilization]

The workpiece processing sheet of the present invention can be suitably used for processing workpieces such as semiconductor wafers.

1: Sheet for workpiece processing 11: Substrate 111: surface layer 112: middle layer 113: back layer 12: Adhesive layer

[ Fig. 1 ] is a cross-sectional view of a workpiece processing sheet according to an embodiment of the present invention.

1: Sheet for workpiece processing

11: Substrate

111: surface layer

112: middle layer

113: back layer

12: Adhesive layer

Claims (7)

A workpiece processing sheet comprising: a substrate, an adhesive layer laminated on one side of the substrate, a workpiece processing sheet, The above-mentioned substrate has: a surface layer located relatively close to the above-mentioned adhesive layer, a back layer located relatively far away from the above-mentioned adhesive layer, and an intermediate layer located between the above-mentioned surface layer and the above-mentioned back layer, The surface layer and the back layer each contain an antistatic agent, The above-mentioned surface layer has a thickness of 10 μm or less. The sheet for workpiece processing according to claim 1, wherein the surface resistivity of the surface of the adhesive layer opposite to the substrate is 1.0×10 ¹³ Ω/□ or less. The workpiece processing sheet according to claim 1, wherein the above-mentioned intermediate layer does not contain the above-mentioned antistatic agent, or, The above-mentioned intermediate layer contains the above-mentioned antistatic agent in a smaller content (unit: mass %) than each of the above-mentioned surface layer and the above-mentioned back layer. The workpiece processing sheet according to claim 1, wherein the antistatic agent is a polymer antistatic agent. The workpiece processing sheet according to claim 1, wherein the thickness of the intermediate layer is not less than 40 μm and not more than 75 μm. The workpiece processing sheet according to claim 1, wherein the thickness of the back layer is not less than 2 μm and not more than 40 μm. The workpiece processing sheet according to claim 1, wherein the workpiece processing sheet is a cutting sheet.

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