JP7621143B2 - Semiconductor processing sheets - Google Patents

Description

The present invention relates to a semiconductor processing sheet used for processing semiconductor wafers, etc.

Semiconductor wafers such as silicon and gallium arsenide and various packages (hereinafter sometimes referred to as "workpieces") are manufactured in a large diameter state, cut (diced) into chips, peeled off (picked up), and then moved to the next process, the mounting process. At this time, the workpieces such as semiconductor wafers are stacked on a sheet (hereinafter sometimes referred to as "semiconductor processing sheet") that comprises a base material and a semiconductor attachment layer such as an adhesive layer, and are then processed, such as backgrinding, dicing, cleaning, drying, expanding, picking up, and mounting.

In full-cut dicing, a typical specific method of dicing described above, a rotating round blade (dicing blade) is used to cut the workpiece. Usually, in order to ensure that the workpiece laminated on the semiconductor processing sheet is cut, not only the workpiece but also the semiconductor adhesive layer and even a part of the substrate are cut. At this time, cutting chips made of the material that constitutes the semiconductor adhesive layer and substrate are generated from the semiconductor processing sheet, and these cutting chips may contaminate the workpiece after cutting. One typical form of the cutting chips is thread-like cutting chips that adhere to the dicing line or near the cross section of the chips separated by dicing.

If the chip is sealed with a large amount of the above-mentioned thread-like cutting chips attached to the chip, the thread-like cutting chips attached to the chip will decompose due to the heat of sealing, and the pyrolysis products may destroy the package or cause malfunctions in the resulting device. The larger the size of these thread-like cutting chips, the more difficult they are to remove by cleaning, so the adhesion of the thread-like cutting chips significantly reduces the yield of the dicing process. Therefore, when dicing is performed using a semiconductor processing sheet, it is necessary to prevent the thread-like cutting chips from adhering to the chip.

In order to prevent the adhesion of the above-mentioned cutting chips, Patent Document 1 discloses the use of a polyolefin-based film obtained by irradiating an electron beam under specified conditions as the base film of a dicing sheet.

JP 2014-187244 A

However, as semiconductor devices continue to become increasingly miniaturized, there is a demand for semiconductor processing sheets that can further suppress the adhesion of cutting chips.

The present invention was made in consideration of these circumstances, and aims to provide a semiconductor processing sheet that is highly effective in preventing cutting chips from adhering to the chip.

In order to achieve the above object, first, the present invention provides a semiconductor processing sheet comprising a substrate and a semiconductor attachment layer laminated on one side of the substrate, the semiconductor processing sheet being cut into a rectangle of 60 mm long side x 15 mm short side, and a cut parallel to the short side is made at the center of the long side from the surface side of the semiconductor attachment layer until the remaining thickness of the substrate becomes 40 μm. When a tensile test was performed at 23 ° C. and 50 ° C. with a chuck distance of 30 mm and a tensile speed of 1000 mm / min, the breaking elongation measured in each of the environments of 23 ° C. and 50 ° C. was expressed as follows:
Breaking elongation at 50 ° C. / Breaking elongation at 23 ° C. ≧ 3.0 ... (1)
The present invention provides a semiconductor processing sheet that satisfies the above requirements (Invention 1).

The semiconductor processing sheet according to the above invention (Invention 1) satisfies the above-mentioned conditions regarding breaking elongation, and can effectively suppress adhesion of cutting chips to the chip.

In the above invention (Invention 1), when the tensile test is performed on the test piece, the breaking energy measured in each of the environments of 23° C. and 50° C. is expressed by the following formula (2):
Breaking energy at 50 ° C. / Breaking energy at 23 ° C. ≧ 2.0 ... (2)
It is preferable that the above condition is satisfied (Invention 2).

In the above inventions (Inventions 1 and 2), it is preferable that the material of the substrate contains at least one of a polyolefin resin and a polyvinyl chloride resin (Invention 3).

In the above inventions (Inventions 1 to 3), it is preferable that the semiconductor attachment layer includes at least one layer of a pressure-sensitive adhesive layer, an adhesive layer, and a protective film-forming layer (Invention 4).

In the above inventions (Inventions 1 to 4), it is preferable to use it for dicing (Invention 5).

When dicing is performed using the semiconductor processing sheet of the present invention, adhesion of cutting chips to the chip can be effectively suppressed.

Hereinafter, an embodiment of the present invention will be described.
The semiconductor processing sheet of this embodiment comprises a substrate and a semiconductor attachment layer laminated on one side of the substrate.

The semiconductor processing sheet according to this embodiment has a breaking elongation (%) at 23 ° C. and a breaking elongation (%) at 50 ° C. measured by a predetermined tensile test, and the breaking elongation (%) satisfies the following formula (1):
Breaking elongation at 50 ° C. / Breaking elongation at 23 ° C. ≧ 3.0 ... (1)
It satisfies the following.

Here, the tensile test is performed by first cutting the semiconductor processing sheet according to this embodiment into a rectangular shape with a long side of 60 mm and a short side of 15 mm. For the cut piece obtained by this cutting, a cut is made parallel to the short side at the center of the long side from the surface side of the semiconductor attachment layer until the remaining thickness of the substrate becomes 40 μm. Here, if the semiconductor processing sheet has a release sheet described later, the release sheet is peeled off and removed. For the test piece obtained in this way, a tensile test is performed at two temperature environments of 23 ° C. and 50 ° C., with a chuck distance of 30 mm and a tensile speed of 1000 mm / min. The breaking elongation (%) measured in this way is the breaking elongation at 23 ° C. and the breaking elongation at 50 ° C. according to the above formula (1).

The semiconductor processing sheet according to this embodiment satisfies the above formula (1) regarding the breaking elongation, and therefore can effectively prevent the chips (especially thread-like chips) generated during dicing with a dicing blade from adhering to the chip. The reasons for this are thought to be as follows. However, the reasons are not limited to those below, and the possibility of a combination of other phenomena or a completely different reason cannot be denied.

In normal dicing, the temperature rises to 50°C or more at the contact points between the rotating dicing blade and the semiconductor wafer or semiconductor processing sheet due to friction between them. At the same time, a force that stretches the material constituting the semiconductor processing sheet is applied at the contact points by being scraped up by the rotating dicing blade. On the other hand, in normal dicing, in order to suppress excessive heating, running water (cutting water) is supplied to the contact points to cool the dicing blade, etc. Here, the semiconductor processing sheet according to this embodiment satisfies the above formula (1), and therefore is more likely to cut (break) at low temperatures such as 23°C than at high temperatures such as 50°C. In such a semiconductor processing sheet, the contact points, i.e., the points where the stretching force is applied, are more likely to stretch. On the other hand, at positions away from the contact points, the stretching force weakens and the sheets are more likely to be cooled by cutting water away from the heat source, making them more likely to be cut. As a result, the semiconductor processing sheet according to this embodiment is less likely to produce long, stretched, thread-like cutting chips, effectively preventing the chips from adhering to the chips.

From the viewpoint of more effectively suppressing adhesion of cutting chips, the above-mentioned breaking elongation ratio (breaking elongation at 50°C/breaking elongation at 23°C) is preferably 5.0 or more, and particularly preferably 6.0 or more. The upper limit of the above-mentioned breaking elongation ratio is not particularly limited, and may be, for example, 30 or less, particularly 20 or less, or even 10 or less.

The breaking elongation at 23°C is preferably 10% or more, more preferably 20% or more, and even more preferably 30% or more. The breaking elongation at 23°C is preferably 100% or less, more preferably 70% or less, and even more preferably 50% or less. By having the breaking elongation at 23°C within these ranges, it becomes easier to achieve the breaking elongation ratio described above.

Furthermore, the breaking elongation at 50°C described above is preferably 100% or more, particularly preferably 200% or more, and even more preferably 250% or more. The breaking elongation at 50°C is preferably 600% or less, particularly preferably 350% or less, and even more preferably 300% or less. By having the breaking elongation at 50°C within these ranges, it becomes easier to achieve the breaking elongation ratio described above.

In addition, in the semiconductor processing sheet according to this embodiment, a test piece is prepared in the same manner as in the measurement of the breaking elongation described above, and the breaking energy at 23 ° C. and the breaking energy at 50 ° C. are measured when the above-mentioned tensile test is performed, and the following formula (2) is used.
Breaking energy at 50 ° C. / Breaking energy at 23 ° C. ≧ 2.0 ... (2)
It is also preferable that the following is satisfied.

In particular, the breaking energy ratio (breaking energy at 50°C/breaking energy at 23°C) is preferably 2.4 or more, and more preferably 5.0 or more. By having the breaking energy ratio in this range, it becomes easier to satisfy the breaking elongation ratio described above, and it becomes easier to effectively suppress adhesion of cutting chips to the chip. The upper limit of the breaking energy ratio described above is not particularly limited, and may be, for example, 25 or less, particularly 21 or less, or even 10 or less.

The above-mentioned breaking energy at 23°C is preferably 20 N·mm or more, particularly preferably 40 N·mm or more, and more preferably 100 N·mm or more. The breaking energy at 23°C is preferably 300 N·mm or less, particularly preferably 200 N·mm or less, and more preferably 150 N·mm or less. When the breaking energy at 23°C is within these ranges, it becomes easier to achieve the above-mentioned breaking energy ratio.

Furthermore, the above-mentioned breaking energy at 50°C is preferably 300 N·mm or more, particularly preferably 500 N·mm or more, and even more preferably 700 N·mm or more. Furthermore, the breaking energy at 50°C is preferably 2000 N·mm or less, particularly preferably 1500 N·mm or less, and even more preferably 1000 N·mm or less. By having the breaking energy at 50°C within these ranges, it becomes easier to achieve the above-mentioned breaking energy ratio.

Details of the method for measuring the breaking elongation and breaking energy are as described in the test examples described below. As described above, in the tensile test for measuring the breaking elongation and breaking energy, the semiconductor processing sheet is cut until the remaining thickness of the substrate is 40 μm. This does not mean that the thickness of the substrate in the semiconductor processing sheet according to this embodiment is necessarily 40 μm or more. In other words, the thickness of the substrate in this embodiment may be less than 40 μm. When the thickness of the substrate is less than 40 μm, the breaking elongation and breaking energy are measured using a semiconductor processing sheet having a test substrate made of the same material as the substrate so that the thickness is 40 μm or more.

1. Substrate The substrate in this embodiment is not particularly limited as long as it satisfies the breaking elongation ratio described above and can exert the desired function when the semiconductor processing sheet is used.

The substrate in this embodiment is preferably a resin film mainly made of a resin-based material, from the viewpoint of making it easier to satisfy the breaking elongation ratio described above. In particular, the substrate in this embodiment preferably contains at least one of a polyolefin-based resin and a polyvinyl chloride-based resin. When the substrate contains these resins, the semiconductor processing sheet is more likely to satisfy the breaking elongation ratio described above.

Preferable examples of the polyolefin resin include polyethylene, polypropylene, polybutene, polybutadiene, polymethylpentene, ethylene-norbornene copolymer, norbornene resin, etc. Also preferred examples of the polyolefin resin include copolymers of ethylene and α-olefin, and copolymers of α-olefin and propylene.

Preferred examples of the above polyethylene include low density polyethylene (LDPE), linear low density polyethylene (LLDPE), high density polyethylene (HDPE), etc. Among these, LDPE and HDPE are preferred.

Preferred examples of the copolymer of ethylene and α-olefin include ethylene-propylene copolymers. In the ethylene-propylene copolymer, the mass ratio of the ethylene monomers and propylene monomers constituting the copolymer is preferably 1:99 to 50:50, more preferably 5:95 to 40:60, and even more preferably 8:92 to 30:70. By using an ethylene-propylene copolymer of this configuration, the semiconductor processing sheet is more likely to satisfy the breaking elongation ratio described above.

Among the above resins, it is preferable to use at least one of LDPE, HDPE, and ethylene-propylene copolymer, from the viewpoint of making it easier to satisfy the breaking elongation ratio mentioned above, and it is particularly preferable to use a mixture of two or more of these resins.

When LDPE is used as the material for the substrate, the LDPE content in the substrate is preferably 5% by mass or more, particularly preferably 10% by mass or more, and even more preferably 15% by mass or more. The LDPE content in the substrate is preferably 99% by mass or less, particularly preferably 97% by mass or less, and even more preferably 95% by mass or less. By having the LDPE content in the above range, the semiconductor processing sheet is more likely to satisfactorily meet the breaking elongation ratio described above.

When HDPE is used as the material for the substrate, the HDPE content in the substrate is preferably 5% by mass or more, particularly preferably 10% by mass or more, and even more preferably 15% by mass or more. The HDPE content in the substrate is preferably 90% by mass or less, particularly preferably 80% by mass or less, and even more preferably 70% by mass or less. By having the HDPE content in the above range, the semiconductor processing sheet is more likely to satisfactorily meet the breaking elongation ratio described above.

When an ethylene-propylene copolymer is used as the material for the substrate, the content of the ethylene-propylene copolymer in the substrate is preferably 5% by mass or more, particularly preferably 10% by mass or more, and more preferably 15% by mass or more. The content of the ethylene-propylene copolymer in the substrate is preferably 90% by mass or less, particularly preferably 85% by mass or less, and more preferably 80% by mass or less. When the content of the ethylene-propylene copolymer is in the above range, the semiconductor processing sheet is more likely to satisfactorily satisfy the breaking elongation ratio described above.

Preferred examples of the polyvinyl chloride resin include polyvinyl chloride, polyvinylidene chloride, vinyl chloride-ethylene copolymer, vinyl chloride-vinyl acetate copolymer, etc. Among these, it is preferable to use polyvinyl chloride from the viewpoint that it is easy to satisfactorily satisfy the breaking elongation ratio described above.

When polyvinyl chloride is used as the material for the substrate, the content of polyvinyl chloride in the substrate is preferably 40% by mass or more, particularly preferably 50% by mass or more, and more preferably 60% by mass or more. The content of polyvinyl chloride in the substrate is preferably 99% by mass or less, particularly preferably 97% by mass or less, and more preferably 95% by mass or less. By having the polyvinyl chloride content in the above range, the semiconductor processing sheet is more likely to satisfactorily satisfy the breaking elongation ratio described above.

The substrate in this embodiment may contain other resins in addition to the above-mentioned resins, or may be made of other resins instead of the above-mentioned resins. Examples of such other resins include ethylene-vinyl acetate copolymers; ethylene-(meth)acrylic acid copolymers, ethylene-methyl (meth)acrylate copolymers, other ethylene-(meth)acrylic acid ester copolymers, and other ethylene-(meth)acrylic acid ester copolymers; polyesters such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate; (meth)acrylic acid ester copolymers; polyurethanes; polyimides; polystyrene; polycarbonates; fluororesins, and the like. In this specification, "(meth)acrylic acid" means both acrylic acid and methacrylic acid. The same applies to other similar terms.

The substrate in this embodiment may be a modified film such as a crosslinked film or an ionomer film made of the above resin. The substrate in this embodiment may also be a laminated film made of a plurality of films made of the above resin. In this laminated film, the materials constituting each layer may be the same or different.

The substrate in this embodiment preferably contains a core-shell rubber in addition to the above resins. In particular, when the substrate in this embodiment contains a polyvinyl chloride resin (particularly polyvinyl chloride), it preferably contains a core-shell rubber.

Examples of the core-shell rubber include methacrylate ester-styrene/butadiene rubber graft copolymer, methacrylate ester-styrene/styrene-butadiene rubber graft copolymer, acrylonitrile-styrene/butadiene rubber graft copolymer, acrylonitrile-styrene/styrene-butadiene rubber graft copolymer, acrylonitrile-styrene/ethylene-propylene rubber graft copolymer, acrylonitrile-styrene/acrylic acid ester rubber graft copolymer, methacrylate ester/acrylic acid ester rubber graft copolymer, methacrylate ester-styrene/acrylic acid ester rubber graft copolymer, and methacrylate ester-acrylonitrile/acrylic acid ester rubber graft copolymer. Among these, methacrylate ester-styrene/acrylic acid ester rubber graft copolymer is preferred, and methyl methacrylate-styrene/ethyl acrylate rubber graft copolymer is particularly preferred.

When core-shell rubber is used as the material for the substrate, the content of the core-shell rubber in the substrate is preferably 1% by mass or more, more preferably 3% by mass or more, and even more preferably 5% by mass or more. The content of the core-shell rubber in the substrate is preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less. By having the content of the core-shell rubber in the above range, the semiconductor processing sheet is more likely to satisfactorily satisfy the breaking elongation ratio described above.

The substrate in this embodiment may contain various additives such as flame retardants, plasticizers, antistatic agents, 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 substrate exhibits the desired function.

The surface of the substrate on which the semiconductor attachment layer is laminated may be subjected to a surface treatment such as a primer treatment, corona treatment, or plasma treatment to improve adhesion to the semiconductor attachment layer.

In this embodiment, the thickness of the substrate is preferably 40 μm or more, more preferably 50 μm or more, and even more preferably 60 μm or more. By making the thickness of the substrate 40 μm or more, the substrate has sufficient strength, and the workpiece can be easily and satisfactorily held on the sheet. The thickness is preferably 300 μm or less, more preferably 200 μm or less, and even more preferably 150 μm or less. By making the thickness of the substrate 300 μm or less, it becomes easier to expand well during the expanding process, etc.

2. Semiconductor attachment layer In this embodiment, the semiconductor attachment layer is not particularly limited in type as long as it can hold the workpiece when processing the workpiece using the semiconductor processing sheet according to this embodiment.Preferred examples of the semiconductor attachment layer include an adhesive layer, a pressure sensitive adhesive layer, a protective film forming layer, and a laminate of two or more of these layers.

When the semiconductor attachment layer is an adhesive layer, the semiconductor processing sheet according to this embodiment can be used as, for example, a die bonding sheet. The material constituting the adhesive layer is not particularly limited as long as it can fix the wafer during dicing and further form an adhesive layer on the individualized chips. Materials constituting such adhesive layers include those made of a thermoplastic resin and a low molecular weight thermosetting adhesive component, and those made of a B-stage (semi-cured) thermosetting adhesive component. Among these, it is preferable that the material constituting the adhesive layer contains a thermoplastic resin and a thermosetting adhesive component. Examples of thermoplastic resins include (meth)acrylic copolymers, polyester resins, urethane resins, phenoxy resins, polybutene, polybutadiene, polyvinyl chloride, polyethylene terephthalate, polybutylene terephthalate, ethylene (meth)acrylic acid copolymers, ethylene (meth)acrylic acid ester copolymers, polystyrene, polycarbonate, polyimide, etc., and among them, (meth)acrylic copolymers are preferable in terms of adhesion and film-forming properties (sheet processability). Examples of thermosetting adhesive components include epoxy resins, polyimide resins, phenol resins, silicone resins, cyanate resins, bismaleimide triazine resins, allylated polyphenylene ether resins (thermosetting PPE), formaldehyde resins, unsaturated polyesters, and copolymers of these. Among these, epoxy resins are preferred from the viewpoint of adhesion.

When the semiconductor attachment layer is an adhesive layer, the semiconductor processing sheet according to this embodiment can be used, for example, as a dicing sheet. The adhesive layer may be composed of a non-active energy ray curable adhesive, or may be composed of an active energy ray curable adhesive. As the non-active energy ray curable adhesive, one having the desired adhesive strength and removability is preferable, and for example, an acrylic adhesive, a rubber adhesive, a silicone adhesive, a urethane adhesive, a polyester adhesive, a polyvinyl ether adhesive, etc. can be used. Among these, an acrylic adhesive that can effectively suppress the falling off of the workpiece, chips, etc. during the dicing process, etc. is preferable.

It is also preferable that the semiconductor attachment layer is a laminate consisting of a pressure-sensitive adhesive layer and an adhesive layer. In this case, it is preferable that the pressure-sensitive adhesive layer is located on the side closer to the substrate, and the adhesive layer is located on the side farther from the substrate. Such a semiconductor processing sheet according to this embodiment can be used, for example, as a dicing/die bonding sheet. As the pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer, for example, the above-mentioned adhesives can be used. Also, as the adhesive constituting the adhesive layer, for example, the above-mentioned adhesives can be used.

It is also preferable that the semiconductor attachment layer is a laminate consisting of an adhesive layer and a protective film forming layer. In this case, it is preferable that the adhesive layer is located on the side closer to the substrate, and the protective film forming layer is located on the side farther from the substrate. Such a semiconductor processing sheet according to the present embodiment can be used for dicing the workpiece, and further, after dicing, a protective film can be formed on the obtained chip by heating the protective film forming layer. It is preferable that the protective film forming layer is made of an uncured curable adhesive. It is also preferable that the protective film forming layer has adhesiveness at room temperature or exhibits adhesiveness when heated. Examples of curable adhesives that constitute the protective film forming layer having these characteristics include those that contain a curable component and a binder polymer component.

The thickness of the semiconductor attachment layer is preferably 3 μm or more, more preferably 5 μm or more, and even more preferably 10 μm or more. The thickness is also preferably 40 μm or less, more preferably 30 μm or less, and even more preferably 20 μm or less. By having the thickness of the semiconductor attachment layer within these ranges, the semiconductor processing sheet is more likely to exhibit the desired performance in semiconductor processing.

3. Release sheet In the semiconductor processing sheet according to this embodiment, a release sheet may be laminated on the surface of the semiconductor attachment layer to which the workpiece is attached until the surface is attached to the workpiece in order to protect the surface.

The release sheet may have any configuration, and may be, for example, a resin film that has been subjected to a release treatment using a release agent or the like. Specific examples of resin films include polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, and polyolefin films such as polypropylene and polyethylene.

The release agent may be silicone-based, fluorine-based, or long-chain alkyl-based, among which silicone-based agents are preferred because they are inexpensive and provide stable performance.

There are no particular limitations on the thickness of the release sheet, but it is usually 20 μm or more and 250 μm or less.

4. Manufacturing Method of Semiconductor Processing Sheet The manufacturing method of the semiconductor processing sheet according to this embodiment is not particularly limited, and general methods can be used.

Methods for producing the substrate include, for example, melt extrusion methods such as the T-die method and the round die method; calendaring methods; and solution methods such as the dry method and the wet method. When producing the substrate by the melt extrusion method, the substrate material is kneaded, and the resulting kneaded mixture is either directly produced or pelletized and then formed into a film using a known extruder.

When the semiconductor attachment layer is made of a pressure sensitive adhesive layer or an adhesive layer, for example, a semiconductor attachment layer can be formed on the release surface of a release sheet, and a substrate can be laminated on the semiconductor attachment layer by pressing, thereby producing a semiconductor processing sheet.

In this case, the semiconductor attachment layer can be formed on the release surface of the release sheet by a general method. First, a coating liquid is prepared that contains a composition containing the material of the pressure-sensitive adhesive layer or adhesive layer, and optionally a solvent or dispersion medium. The coating liquid is then applied to the release surface of the release sheet using a coating machine such as a roll coater, knife coater, roll knife coater, air knife coater, die coater, bar coater, gravure coater, curtain coater, etc., and the semiconductor attachment layer can be formed by drying, etc.

When the semiconductor attachment layer is a laminate consisting of an adhesive layer and a bonding layer, or a laminate consisting of an adhesive layer and a protective film forming layer, first, a first laminate consisting of a release sheet, an adhesive layer, and a substrate laminated in this order is obtained by the above-mentioned method. In parallel with this, a coating liquid containing a composition containing a material for the adhesive layer or protective film forming layer, and optionally further a solvent or dispersion medium, is applied to the release surface of the release sheet using the above-mentioned coater, and dried, etc., to obtain a second laminate consisting of the release sheet and the adhesive layer or protective film forming layer. Next, the release sheet is peeled off from the first laminate, and the exposed surface on the adhesive layer side is bonded to the surface on the bonding layer side or protective film forming layer side of the second laminate, thereby obtaining a semiconductor processing sheet.

5. Method of using the semiconductor processing sheet The semiconductor processing sheet according to this embodiment can be used for processing semiconductor materials. That is, after the semiconductor attachment layer side of the semiconductor processing sheet according to this embodiment is attached to the workpiece (semiconductor material), the workpiece can be processed on the semiconductor processing sheet. Examples of the workpiece (semiconductor material) include semiconductor chips, semiconductor wafers, semiconductor packages, etc. Examples of processing include back grinding, dicing, expanding, picking up, etc.

The above-described embodiments are described to facilitate understanding of the present invention, and are not described to limit the present invention. Therefore, each element disclosed in the above embodiments is intended to include all design modifications and equivalents that fall within the technical scope of the present invention.

For example, other layers may be provided between the substrate and the semiconductor attachment layer, or on the surface of the substrate opposite the semiconductor attachment layer.

The present invention will be explained in more detail below with reference to examples, but the scope of the present invention is not limited to these examples.

[Preparation Example 1] (Preparation of Adhesive Composition)
An adhesive composition was obtained by mixing the following acrylic polymer, epoxy resin, curing agent/curing accelerator, filler, thermoplastic resin, photopolymerization initiator, and silane coupling agent, and then the resulting mixture was mixed in methyl ethyl ketone so that the solid content concentration was 40 mass %, to prepare a coating liquid of the adhesive composition.
<Acrylic Polymer>
100 parts by mass of an acrylic polymer (weight average molecular weight: 700,000) obtained by copolymerizing 55 parts by mass of n-butyl acrylate (solid content equivalent, the same applies below), 10 parts by mass of methyl acrylate, 18 parts by mass of glycidyl methacrylate, and 17 parts by mass of 2-hydroxyethyl acrylate by a solution polymerization method <epoxy resin>
150 parts by mass of triphenylene type epoxy resin (manufactured by Nippon Kayaku Co., Ltd., product name "EPPN-502H", epoxy equivalent: 167, softening point: 54°C, weight average molecular weight: 1200) 150 parts by mass of acrylic rubber microparticle-dispersed epoxy resin (manufactured by Nippon Shokubai Co., Ltd., product name "Acryset BPA328", epoxy equivalent: 235, liquid) <hardening agent/hardening accelerator>
140 parts by weight of novolak phenolic resin (manufactured by Showa Polymer Co., Ltd., product name "BRG-556", hydroxyl equivalent: 104, softening point: 80°C) 2 parts by weight of 2-phenyl-4,5-dihydroxymethylimidazole (manufactured by Shikoku Kasei Co., Ltd., product name "Curesol 2PHZ-PW") <filler>
Silica filler (manufactured by Admatechs Co., Ltd., product name "Admafine SC2050MA", surface modification: epoxy group modification, average particle size: 500 nm) 90 parts by mass <thermoplastic resin>
Polyester resin (manufactured by Toyobo Co., Ltd., product name "Vylon 220", number average molecular weight: 3000, glass transition temperature: 53° C.) 135 parts by weight <ultraviolet ray curing component>
35 parts by weight of tricyclodecane dimethylol diacrylate (manufactured by Nippon Kayaku Co., Ltd., product name "KAYARAD R-684", molecular weight: 304) <photopolymerization initiator>
1 part by mass of 1-hydroxycyclohexyl phenyl ketone (manufactured by BASF, product name "IRGACURE 184") <Silane coupling agent>
4 parts by mass of a silicate compound to which 3-glycidoxypropyltrimethoxysilane has been added (manufactured by Mitsubishi Chemical Corporation, product name "MSEP2") 1.5 parts by mass of phenylaminopropyltrimethoxysilane (manufactured by Toray Industries, Inc., product name "DOWSIL Z-6883 Silane")

[Preparation Example 2] (Preparation of Pressure-Sensitive Adhesive Composition)
95 parts by mass of n-butyl acrylate and 5 parts by mass of 2-hydroxyethyl acrylate were copolymerized by solution polymerization to obtain an acrylic polymer (weight average molecular weight: 800,000). 100 parts by mass of the acrylic polymer and 5 parts by mass of trimethylolpropane-modified tolylene diisocyanate (manufactured by Toyochem Co., Ltd., product name "BHS8515") as a crosslinking agent were mixed in ethyl acetate to a solid content concentration of 30% by mass to prepare a coating solution of a pressure-sensitive adhesive composition.

Example 1
(1) Preparation of Substrate 52.5 parts by mass of low-density polyethylene, 22.5 parts by mass of high-density polyethylene, and 25 parts by mass of an ethylene-propylene copolymer (the mass ratio of ethylene monomer to propylene monomer was 10:90) were extruded using a small T-die extruder (manufactured by Toyo Seiki Seisakusho, product name "Labo Plastomill") to obtain a substrate having a thickness of 80 μm.

(2) Formation of Adhesive Layer A first release sheet (manufactured by Lintec Corporation, product name "SP-PET381031", thickness: 38 μm) consisting of a 38 μm-thick polyethylene terephthalate (PET) film with a silicone-based release agent layer formed on one side thereof, and a second release sheet (manufactured by Lintec Corporation, product name "SP-PET381130", thickness: 38 μm) consisting of a 38 μm-thick PET film with a silicone-based release agent layer formed on one side thereof were prepared.

Next, the coating solution of the adhesive composition prepared in Preparation Example 1 was applied to the release surface of the first release sheet using a knife coater and dried to form a 5 μm thick adhesive layer on the release surface of the first release sheet. The release surface of the second release sheet was then placed on top of the adhesive layer and bonded to each other to obtain a laminate consisting of the first release sheet, the adhesive layer (thickness: 5 μm), and the second release sheet. The laminate was then aged for 7 days in an environment at a temperature of 23°C and a relative humidity of 50%.

(3) Preparation of semiconductor processing sheet The second release sheet was peeled off from the laminate formed in the above step (2) to expose the adhesive layer. The exposed surface of this adhesive layer was attached to one side of the substrate prepared in the above step (1). The laminate obtained by this attachment was stored for one week under an environment of 23°C and 50% humidity. As a result, a semiconductor processing sheet was obtained in which the release sheet, the adhesive layer as the semiconductor attachment layer, and the substrate were laminated in order.

[Examples 2 to 4]
A semiconductor processing sheet was obtained in the same manner as in Example 1, except that the type and compounding ratio of the substrate material were changed as shown in Table 1.

Example 5
A coating solution of the adhesive composition prepared in Preparation Example 2 was applied to the release surface of a release sheet (manufactured by Lintec Corporation, product name "SP-PET3801") consisting of a silicone-based release agent layer formed on one side of a 38 μm-thick PET film using a comma coater, and the resulting coating was dried at 90° C. for 1 minute to form an adhesive layer of 10 μm thickness on the release sheet. This resulted in a laminate consisting of the adhesive layer as a semiconductor attachment layer and the release sheet.

Meanwhile, 50 parts by mass of low-density polyethylene and 50 parts by mass of ethylene-propylene copolymer (mass ratio of ethylene to propylene is 10:90) were extruded using a small T-die extruder (manufactured by Toyo Seiki Seisakusho, product name "Labo Plastomill") to obtain a substrate with a thickness of 80 μm.

The adhesive layer side of the laminate consisting of the adhesive layer and release sheet obtained as described above was attached to one side of the substrate obtained as described above, and then stored for one week in an environment of 23°C and 50% humidity. This resulted in a semiconductor processing sheet consisting of a release sheet, an adhesive layer as a semiconductor attachment layer, and a substrate laminated in that order.

Example 6
A laminate consisting of a first release sheet, an adhesive layer, and a second release sheet was obtained in the same manner as in step (2) of Example 1. The second release sheet was peeled off from the laminate to expose the adhesive layer.

On the other hand, in the same manner as in Example 5, a semiconductor processing sheet was obtained in which a release sheet, an adhesive layer, and a substrate were laminated in that order. The release sheet was peeled off from the semiconductor processing sheet to expose the adhesive layer.

The exposed surface of the adhesive layer and the exposed surface of the pressure-sensitive adhesive layer were then bonded together, and the resulting sheet was stored for one week in an environment of 23°C and 50% humidity. As a result, a semiconductor processing sheet was obtained as Example 6, which is made up of a release sheet, an adhesive layer as a semiconductor attachment layer, a pressure-sensitive adhesive layer as a semiconductor attachment layer, and a substrate laminated in that order.

Comparative Examples 1 to 4
A semiconductor processing sheet was obtained in the same manner as in Example 1, except that the type and compounding ratio of the substrate material were changed as shown in Table 1.

Comparative Example 5
An ethylene-methacrylic acid copolymer (EMAA) (manufactured by Mitsui DuPont Polychemicals, product name "Nucrel N0903HC") was extruded using a small T-die extruder (manufactured by Toyo Seiki Seisakusho, product name "Labo Plastomill") to obtain an EMAA film having a thickness of 80 μm.

The obtained film was passed through an electron beam irradiation device (manufactured by ESI, product name "TYPE300/165/800") at a speed of 45 m/min, whereby one of the main surfaces of the film was irradiated with electron beams under the following irradiation conditions.
Irradiation amount: 110kGy
Irradiation time: 2.2 seconds Since the number of irradiations was one, the above-mentioned irradiation amount and irradiation time correspond to the integrated irradiation amount and integrated irradiation time, respectively.

A semiconductor processing sheet was obtained in the same manner as in Example 1, except that the EMAA film obtained above and irradiated with an electron beam (EB) was used as the substrate.

[Test Example 1] (Measurement of breaking elongation and breaking energy)
The semiconductor processing sheets manufactured in the examples and comparative examples were cut into rectangular shapes with long sides of 60 mm and short sides of 15 mm to obtain cut pieces. At this time, the long sides of the cut pieces were cut so as to be parallel to the MD direction of the substrate (the flow direction during the manufacture of the substrate).

Next, an incision was made in the cut piece at a position that divided it in half along the long side (a position that would create two rectangles with long sides of 30 mm and short sides of 15 mm). In other words, an incision was made in the center of the long side of the cut piece, parallel to the short side. The incision was made from the surface facing the release sheet, and the depth of the incision was set so that the remaining thickness of the substrate was 40 μm. The release sheet was then peeled off and removed to obtain a test piece.

A tensile test was performed on the obtained test pieces in an environment of 23°C using a tensile testing machine (Shimadzu Corporation, product name "Autograph AG-IS 500N"), with the distance between the chucks set to 30 mm, at a speed of 1000 mm/min to pull the test pieces in the long side direction, and the breaking elongation (%) and breaking energy (N mm) were measured. The results are shown in Table 1 as breaking elongation and breaking energy at 23°C.

The test pieces obtained in the same manner as above were subjected to tensile tests in an environment of 50°C, and the breaking elongation (%) and breaking energy (N mm) were measured. The results are also shown in Table 1 as breaking elongation and breaking energy at 50°C.

Furthermore, based on the breaking elongation and breaking energy measured as described above, the ratio of the breaking elongation at 50°C to the breaking elongation at 23°C (breaking elongation at 50°C/breaking elongation at 23°C) and the ratio of the breaking energy at 50°C to the breaking energy at 23°C (breaking energy at 50°C/breaking energy at 23°C) were calculated. These results are also shown in Table 1.

[Test Example 2] (Measurement of the number of cutting chips)
The release sheet was peeled off from the semiconductor processing sheet produced in the examples and comparative examples, and the exposed surface of the semiconductor attachment layer (adhesive layer or pressure-sensitive adhesive layer) was attached to one side of a semiconductor wafer (a 40 μm thick 8-inch wafer cut into 1/4). The semiconductor wafer was then diced under the following dicing conditions to be divided into individual chips of 8 mm×8 mm.
<Dicing conditions>
- Dicing equipment: Disco Corporation, product name "DFD-651"
Blade: Disco, product name "27HEEE"
・Blade thickness: 0.020 to 0.025 mm
・Blade tip exposure: 0.510 to 0.640 mm
Blade rotation speed: 30,000 rpm
Cutting speed: 50 mm/sec. Cutting depth: 20 μm to the base material
・Cutting water amount: 1.0L/min ・Cutting water temperature: 20℃

The obtained semiconductor chip was removed from the semiconductor processing sheet, and the number of cutting chips adhering to the dicing line of the surface of the semiconductor chip attached to the semiconductor processing sheet was counted. At this time, the cutting chips adhering along the dicing line parallel to the MD direction of the substrate and the cutting chips adhering along the dicing line parallel to the direction perpendicular to the MD direction (CD direction) were counted separately. In addition, the measurement was performed using multiple conductor chips until the total measured distance of the dicing line in each of the MD and CD directions reached 40 cm. The number of cutting chips in the MD direction, the number of cutting chips in the CD direction, and the total number of these are shown in Table 1.

Details of the abbreviations and the like in Table 1 are as follows.
LDPE: Low density polyethylene HDPE: High density polyethylene PP-PE copolymer: Ethylene-propylene copolymer (mass ratio of ethylene to propylene is 10:90)
PVC: Polyvinyl chloride Core-shell rubber: Methyl methacrylate-styrene/ethyl acrylate rubber graft copolymer (manufactured by Mitsubishi Chemical Corporation, product name "Metablen W-300A")
TPO: Olefin-based thermoplastic elastomer EMAA: Ethylene-methacrylic acid copolymer (manufactured by Mitsui DuPont Polychemicals, product name "Nucrel N0903HC")

As can be seen from Table 1, the number of cutting chips was significantly smaller in the semiconductor processing sheet manufactured in the embodiment than in the comparative example.

The semiconductor processing sheet of the present invention can be suitably used for processing semiconductor wafers, etc.

Claims (4)

A semiconductor processing sheet comprising a substrate and a semiconductor attachment layer laminated on one side of the substrate,
The semiconductor processing sheet was cut into a rectangle with a long side of 60 mm and a short side of 15 mm, and a cut was made parallel to the short side at the center of the long side from the surface side of the semiconductor attachment layer until the remaining thickness of the substrate became 40 μm. When a tensile test was performed at 23 ° C. and 50 ° C. with a chuck distance of 30 mm and a tensile speed of 1000 mm / min, the breaking elongation measured in each environment at 23 ° C. and 50 ° C. was expressed by the following formula (1)
Breaking elongation at 50 ° C. / Breaking elongation at 23 ° C. ≧ 3.0 ... (1)
Fulfilling
When the tensile test was performed on the test piece, the breaking energy measured in each of the environments of 23° C. and 50° C. was calculated based on the following formula (2):
Breaking energy at 50 ° C. / Breaking energy at 23 ° C. ≧ 2.0 ... (2)
Fulfill
A semiconductor processing sheet characterized in that 2. The semiconductor processing sheet according to claim 1 , wherein the material of the substrate includes at least one of a polyolefin resin and a polyvinyl chloride resin. 3. The semiconductor processing sheet according to claim 1, wherein the semiconductor attachment layer includes at least one layer of a pressure-sensitive adhesive layer, an adhesive layer, and a protective film-forming layer. The semiconductor processing sheet according to any one of claims 1 to 3, characterized in that it is used for dicing.