WO2018164175A1

WO2018164175A1 - Adhesive tape for semiconductor processing

Info

Publication number: WO2018164175A1
Application number: PCT/JP2018/008737
Authority: WO
Inventors: 具朗内山; 裕介五島
Original assignee: 古河電気工業株式会社
Priority date: 2017-03-10
Filing date: 2018-03-07
Publication date: 2018-09-13
Also published as: TWI705119B; SG11201907365RA; KR20190085059A; JP6667468B2; JP2018152420A; TW201833276A; MY197838A; CN110073470B; KR102267114B1; CN110073470A

Abstract

An adhesive tape for semiconductor processing, which is composed of a substrate and an adhesive layer that is provided on one surface of the substrate, and which is characterized in that: the substrate has a multilayer structure; at least one layer of the multilayer structure is a layer A that contains 80% by mass or more of a cyclic olefin polymer; and the multilayer structure comprises, in addition to the layer A, a layer B that contains a linear low-density polyethylene or a high-density polyethylene.

Description

Adhesive tape for semiconductor processing

The present invention relates to a pressure-sensitive adhesive tape for semiconductor processing, more particularly to a pressure-sensitive adhesive tape for semiconductor processing used during processing of a semiconductor wafer, and more particularly to a method for manufacturing a semiconductor chip that is singulated into chips by back grinding of a semiconductor wafer. It is related with the surface protection adhesive tape for semiconductor processing used.

In a processing process of a semiconductor wafer (hereinafter also referred to as a wafer), after forming a pattern on the wafer surface, so-called back surface grinding / polishing is performed in which the back surface of the wafer is ground and polished to a predetermined thickness. At that time, for the purpose of protecting the wafer surface, a surface protective adhesive tape is bonded to the wafer surface, and the wafer back surface is ground in that state. As the surface protective pressure-sensitive adhesive tape, one in which a pressure-sensitive adhesive layer mainly composed of an acrylic polymer is provided on a plastic film such as polyolefin has been proposed (for example, see Patent Document 1).

On the other hand, with the spread of IC cards, the rapid increase in capacity of semiconductor memories represented by USB memories, and the spread of small devices such as smartphones and tablets, further thinning of the chips is required. For example, a chip having a thickness of about 200 to 350 μm is required to be thinned to a thickness of 50 to 100 μm or less.

Usually, the wafer on which the circuit pattern is formed is processed thinly in the back grinding process. The thin film wafer after grinding is likely to be bent (hereinafter referred to as warpage) due to the difference in shrinkage between the silicon and the circuit, the protective layer, and the shrinkage of the adhesive tape. As the chip becomes thinner, the rigidity of the wafer itself decreases, which may cause a problem of warping that makes it impossible to carry or process the wafer in the apparatus.

In addition, when the finished thickness of the wafer after back grinding is 100 μm or less, the strength of the wafer decreases, cracks may occur starting from slight impacts and defects, and the yield may decrease. Even if cracks do not occur during backside grinding, the chip is mechanically cut with a diamond blade in the subsequent chip singulation (hereinafter referred to as dicing) process, so the chip is caused by chipping (hereinafter referred to as chipping) generated from the cutting line. May break.

Regarding the processing of the thin film wafer as described above, for example, Patent Document 2 discloses that the wafer thickness larger than the wafer thickness planned to be finished by dicing from the wafer circuit side to the predetermined position (chip division planned position) before the back surface grinding is larger than the original wafer thickness. A method of dividing a wafer has been proposed in which a groove having a smaller depth is formed, and then the thickness of the groove is reduced to a depth greater than the depth of the groove by backside grinding, and backside grinding and chip formation are performed simultaneously.

As a method similar to the above, for example, in Patent Document 3, laser irradiation is performed at a chip division planned position, a modified layer is formed inside the wafer instead of a groove, and the modified layer is divided as a starting point during backside grinding.・ Laser processing methods for chip formation have also been proposed. When this method is used, since there is no conventional groove, the distance between the chips can be made almost zero, and more chips can be obtained from one wafer. Further, since there is no impact of cutting with a diamond blade, chipping can be eliminated.

JP 2001-240842 A Japanese Patent Laid-Open No. 11-40520 JP 2002-192370 A

On the other hand, in the method described in Patent Document 3, since the modified layer is formed by a laser, the distance between the chips is almost zero, and due to external factors such as deformation of the surface protection tape and shear force during back surface grinding. When the chip is displaced, there is a problem that it easily contacts with an adjacent chip and a crack is likely to be generated from that part.
In addition, as a result of intensive studies, the present inventors have found that when a base material having a multilayer structure having a specific layer is used as a tape base material, adhesion between layers constituting the multilayer structure is important. Thus, it has been found that if this interlaminar adhesion is not sufficient, the releasability is lowered, or peeling occurs between layers during processing of a semiconductor wafer as an adherend, and the wafer is damaged.

Therefore, the present invention solves the above-mentioned problems, and even when grinding to a thin film in the processing of semiconductor wafers, particularly back grinding of silicon wafers, etc., it has excellent peelability and excellent interlayer adhesion, and is further defective. It is an object of the present invention to provide an adhesive tape for semiconductor processing that can sufficiently suppress the generation of chips.

The above-described problems of the present invention have been solved by the following means.
(1)
A pressure-sensitive adhesive tape comprising a base material and a pressure-sensitive adhesive layer provided on one side of the base material, wherein the base material has a multi-layer structure, and at least one layer of the multi-layer structure is composed of 80 masses of a cyclic olefin polymer. % Of layer A, and a layer B containing linear low-density polyethylene or high-density polyethylene separately from the layer A, a pressure-sensitive adhesive tape for semiconductor processing.
(2)
The density of the said linear low density polyethylene is 0.95 g / cm < ³ > or less, The adhesive tape for semiconductor processing as described in (1) characterized by the above-mentioned.
(3)
The adhesive tape for semiconductor processing according to (1) or (2), wherein the melt flow rate of the linear low density polyethylene is 4.0 g / 10 min or less.
(4)
The pressure-sensitive adhesive tape for semiconductor processing according to any one of (1) to (3), wherein the linear low-density polyethylene is metallocene polyethylene.
(5)
A semiconductor wafer in which a modified layer is formed inside the semiconductor wafer by irradiating a laser along the individual separation area of each chip, or a groove is formed by mechanical means along the individual separation area of each chip. The adhesive tape for semiconductor processing according to any one of (1) to (4), wherein the adhesive tape is used for manufacturing a semiconductor chip in which a semiconductor wafer is separated into chips by grinding the back surface of the semiconductor wafer. .

The pressure-sensitive adhesive tape for semiconductor processing of the present invention has excellent releasability and excellent interlayer adhesion even when ground to a thin film in the processing of semiconductor wafers, especially backside grinding of silicon wafers, etc., and further generates defective chips. It can be sufficiently suppressed.
Moreover, the adhesive tape for semiconductor processing of the present invention is excellent in releasability even if it is ground into a thin film by using it in a semiconductor chip manufacturing method in which chips are separated by back grinding of a semiconductor wafer. The adhesiveness is excellent, and the generation of defective chips can be sufficiently suppressed.
The above and other features and advantages of the present invention will become more apparent from the following description, with reference where appropriate to the accompanying drawings.

FIG. 1 is a schematic cross-sectional view schematically showing an embodiment of the pressure-sensitive adhesive tape for semiconductor processing of the present invention. 2 (a) to 2 (c) are schematic cross-sectional views illustrating the processing steps of a semiconductor wafer using the semiconductor processing adhesive tape of the present invention. FIG. 2 (a) shows the process of peeling the release film from the semiconductor processing adhesive tape to expose the adhesive layer, and FIG. 2 (b) shows the semiconductor processing adhesive tape affixed to the convex side of the semiconductor wafer. FIG. 2C shows a process of grinding the back surface of the semiconductor wafer.

[Semiconductor processing adhesive tape]
The pressure-sensitive adhesive tape for semiconductor processing of the present invention is a pressure-sensitive adhesive tape comprising a base material and a pressure-sensitive adhesive layer provided on one side of the base material, and the base material has a multi-layer structure. At least one layer is a layer A containing 80% by mass or more of a cyclic olefin polymer, and has a layer B containing linear low density polyethylene or high density polyethylene separately from this layer A.
The preferable form of the adhesive tape for semiconductor processing of this invention is demonstrated below.

The adhesive tape 1 for semiconductor processing of the present invention is a tape in which an adhesive layer 3 is laminated on a substrate 2 and both layers are integrated as shown in FIG. The semiconductor processing pressure-sensitive adhesive tape 1 may further include a release film 4 on the pressure-sensitive adhesive layer 3 for protecting the pressure-sensitive adhesive layer 3. The pressure-sensitive adhesive tape 1 for semiconductor processing according to the present invention may be formed by rolling a laminate of the base material 2, the pressure-sensitive adhesive layer 3 and the release film 4 into a roll shape.

(Substrate 2)
The substrate 2 of the adhesive tape 1 for semiconductor processing of the present invention has a multilayer structure. At least one layer of this multilayer structure is a layer A containing a cyclic olefin polymer (hereinafter referred to as “COP”). Separately from this layer A, as at least one layer of the multilayer structure, A layer B containing low-density polyethylene or high-density polyethylene.

In the present specification, COP means a ring-opening polymer of a cyclic olefin, a hydrogenated product thereof, or an addition polymer of a cyclic olefin, and is called a cyclic olefin copolymer (hereinafter referred to as “COC”) Also included are addition copolymers with chain olefins.
The cyclic olefin as a monomer is a cyclic alkene or alkyne, and may be any compound that can form a polymer by ring-opening polymerization or addition polymerization. The number of carbon atoms is preferably 4-12. The cyclic olefin may contain a bicyclic olefin, and may further contain a monocyclic olefin and / or a tricyclic or higher polycyclic olefin. Examples of the monocyclic olefin include cyclic cycloolefins having 4 to 12 carbon atoms such as cyclobutene, cyclopentene, cycloheptene, and cyclooctene. Examples of the bicyclic olefin or the tricyclic or higher polycyclic olefin include dicyclopentadiene; 2,3-dihydrodicyclopentadiene, methanooctahydrofluorene, dimethanooctahydronaphthalene, dimethanocyclopentadienonaphthalene, Derivatives such as methanooctahydrocyclopentadienonaphthalene; derivatives having substituents such as 6-ethyl-octahydronaphthalene; adducts of cyclopentadiene and tetrahydroindene and the like, tripentamers of cyclopentadiene, norbornene, and Examples include tetracyclododecene, and norbornene and tetracyclododecene are preferable.
The chain olefin may be a chain-like alkene or alkyne that can form a polymer by addition polymerization with a cyclic olefin. The number of carbon atoms is preferably 2 to 10, more preferably 2 to 8, and further preferably 2 to 4. Specifically, it has 2 to 10 carbon atoms such as ethylene, propylene, 1-butene, isobutene, 1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-hexene and 1-octene. Examples thereof include chain olefins. These chain olefins can be used alone or in combination of two or more, and ethylene is particularly preferable.
In the layer A, the content of COP is 80% by mass or more, and preferably 90% by mass or more. There is no restriction | limiting in particular in an upper limit, It is 100 mass% or less. When the COP is COC, the COP content is the COC content.
Specific examples of the COP include “ZEONOR” manufactured by Nippon Zeon Co., Ltd. and “Topas” manufactured by Polyplastics Co., Ltd.

Among the COPs, the homopolymer of cyclic olefin is an amorphous resin, has a hard and brittle property, and requires high-temperature treatment when molding a sheet or film.
On the other hand, since COC is a copolymer of cyclic olefin and ethylene, it has flexibility and ductility. Moreover, COC which has various characteristics is obtained by adjusting a polymerization ratio (content ratio).
Among the constituent components of COC, the ethylene component content is preferably 30 to 40% by mass, more preferably 35 to 40% by mass. When there is too little ethylene component content, a base material will be very weak and there exists a possibility that the adhesive tape for semiconductor processing may fracture | rupture. Moreover, when there is too much ethylene component content, the property of an ethylene component will become strong and there exists a possibility that sufficient rigidity may not be obtained.

The substrate 2 is a layer different from the layer A containing COP, and is a linear low-density polyethylene (hereinafter referred to as “LLDPE”) or high-density polyethylene (having good adhesion to the layer A). Hereinafter referred to as “HDPE”). Note that low density polyethylene (hereinafter referred to as “LDPE”) is not preferable because sufficient interlayer adhesion with the layer A cannot be obtained. If the interlayer adhesion is insufficient, the peelability may be insufficient, or peeling may occur between layers during processing of a semiconductor wafer as an adherend, and the wafer may be damaged.

LLDPE and HDPE may be a copolymer of ethylene and α-olefin. As the α-olefin, those having 3 to 10 carbon atoms are preferable, and propylene, butene-1, pentene-1, hexene-1, 4-methylpentene-1, heptene-1, octene-1, and the like are preferable. Can be mentioned.
When LLDPE and HDPE are copolymers of ethylene and α-olefin, the content of the ethylene component is preferably 95 to 99% by mass and more preferably 96 to 98% by mass in all the constituent components of the copolymer.

In the layer B, the content of LLDPE and HDPE is preferably 50% by mass or more, and more preferably 80% by mass or more. There is no restriction | limiting in particular in an upper limit, It is 100 mass% or less. When LLDPE and HDPE are a copolymer of ethylene and α-olefin, the content of LLDPE and HDPE is the content of a copolymer of ethylene and α-olefin.

The density of LLDPE is preferably from 0.95 g / cm ³ or less, more preferably 0.94 g / cm ³ or less, more preferably 0.93 g / cm ³ or less. The lower limit is practically 0.89 g / cm ³ or more.
The melt flow rate (MFR) of LLDPE is preferably 4.0 g / 10 min or less, more preferably 2.0 g / 10 min or less, and even more preferably 1.0 g / 10 min or less. The lower limit is practically 0.5 g / 10 min or more.
Moreover, the density of HDPE is preferably 0.97 g / cm ³ or less, and more preferably 0.96 g / cm ³ or less. The lower limit is practically 0.5 g / cm ³ or more.
HDPE has an MFR (melt flow rate) of preferably 6.0 g / 10 min or less, and more preferably 5.0 g / 10 min or less. The lower limit is practically 0.5 g / 10 min or more.
MFR is a value at a temperature of 190 ° C. and a load of 21.18 N, and the density and MFR can be measured by the method described in the examples.

As LLDPE, metallocene polyethylene is particularly preferable from the viewpoint of adhesion to the layer A containing COC.
In the present specification, “metallocene polyethylene” means an ethylene-based polyolefin obtained by using a metallocene catalyst (hereinafter sometimes referred to as “metallocene-catalyzed ethylene-based polyolefin”), and ethylene, or ethylene and α-olefin. Is obtained by polymerizing in the presence of a metallocene catalyst. Accordingly, the ethylene-based polyolefin obtained using the metallocene catalyst includes polyethylene obtained by conducting a polymerization reaction in the presence of the metallocene catalyst, and a copolymer of ethylene and an α-olefin.

The metallocene catalyst is a general term for a metallocene, that is, a catalyst comprising a transition metal component composed of a complex composed of two substituted or unsubstituted cyclopentadienyl rings and various transition metals, and an organoaluminum component, particularly an aluminoxane. It is. Examples of the transition metal component include metals of groups IVb, Vb or VIb of the periodic table, particularly zirconium or hafnium. The transition metal component in the catalyst is generally represented by the following formula (Cp) ₂ MR ₂
(Wherein Cp is a substituted or unsubstituted cyclopentadienyl ring, M is a transition metal, and R is a halogen atom or an alkyl group) is generally used. .

The aluminoxane is obtained by reacting an organoaluminum compound with water, and includes a linear aluminoxane and a cyclic aluminoxane. These aluminoxanes can be used alone or in combination with other organic aluminum.

A method for polymerizing ethylene or ethylene and α-olefin using a metallocene catalyst is known in many publications, and is synthesized by polymerization in an organic solvent, in a liquid monomer or in a gas phase method in the presence of the metallocene catalyst. However, any of these known methods satisfying the above conditions can be used for the purpose of the present invention.

In the case of a copolymer of ethylene and an α-olefin, the specific α-olefin and the content of the ethylene component in all the constituent components of the copolymer are the copolymer of ethylene and the α-olefin in the LLDPE. The description in can be preferably applied.

The metallocene-catalyzed ethylene-based polyolefin is characterized by a narrow molecular weight distribution. In the present invention, the polydispersity (mass average molecular weight Mw / number average molecular weight Mn), which is an index of molecular weight distribution, is preferably 4.0 or less, More preferably 3.5 or less, and still more preferably 3.2 or less. For the purpose of improving moldability, those having relatively long chain branches introduced during polymerization or in subsequent steps are also preferably used. The metallocene-catalyzed ethylene-based polyolefin usually has a density of 0.89 to 0.95 g / cm ³ , preferably about 0.91 to 0.93 g / cm ³ and an MFR of 0.1 to 10 g / cm ^3. 10 minutes, preferably about 0.3 to 5 g / 10 minutes.

The presence of the metallocene-catalyzed ethylene-based polyolefin in layer B can be confirmed by the following method. That is, the layer B is cut into a glass having a thickness of 100 μm to form a sample, which is laid on a scanning electron microscope SEM and measured with an analyzer that distributes the generated fluorescent X-rays. Zr (zirconium) or Hf (hafnium) The presence of a peak corresponding to the energy of.

As the metallocene-catalyzed ethylene-based polyolefin, a synthetic product can be used, but it can also be selected from commercially available products. Commercially available products include Umerit (registered trademark) manufactured by Ube Maruzen Polyethylene Co., Ltd., Excellen (registered trademark) manufactured by Sumitomo Chemical Co., Ltd., Harmolex (registered trademark) manufactured by Nippon Polyethylene Co., Ltd., and Kernel (registered trademark). .

Since the LLDPE and HDPE are flexible, they have good cushioning properties during wafer grinding. From the viewpoint of heat resistance, the melting point of the resin is preferably 60 ° C. or higher.
Each resin may be used alone as a layer constituting the substrate 2 or may be used by blending resins in combination. Moreover, the layer which comprises the base material 2 may contain additives, such as a coloring agent, antioxidant, and antistatic agent, in the range which does not affect a physical property as needed other than the said resin. .

The thickness of the substrate 2 is not particularly limited, but is preferably 50 to 200 μm, and more preferably 80 to 180 μm.
The thickness of the layer A is preferably 20 to 100 μm and more preferably 30 to 60 μm from the viewpoint of rigidity. The thickness of the layer B is preferably 10 to 100 μm and more preferably 20 to 80 μm from the viewpoint of flexibility.
When the substrate 2 has two or more layers A and two or more layers B, “the thickness of layer A” and “the thickness of layer B” mean the total thickness of each layer.

The layer structure of the substrate 2 is not particularly limited as long as it has a multilayer structure including at least one layer A and one layer B, but the layer structure in which the layer A and the layer B are laminated adjacent to each other. preferably, the layer B _{1 /} layer a / layer B ₂ is 3 or more layers structure is more preferable are laminated in this order, more preferably 3-layer structure in which a layer B _{1 /} layer a / layer B ₂ are laminated in this order . Here, the layer B ₁ and the layer B ₂ mean the layer B, and may be the same layer or different layers.

The surface of the substrate 2 on the side where the pressure-sensitive adhesive layer 3 is provided may be appropriately subjected to a treatment such as a corona treatment or a primer layer in order to improve the adhesion with the pressure-sensitive adhesive layer 3.

The method for manufacturing the substrate 2 is not particularly limited. It can be produced by information such as extrusion, inflation and casting. Moreover, the film formed independently and another film can be bonded together with an adhesive etc., and it can also be set as the base material 2.

(Adhesive layer 3)
The pressure-sensitive adhesive layer 3 of the semiconductor processing pressure-sensitive adhesive tape 1 of the present invention may be a layer containing a pressure-sensitive adhesive, and is formed using, for example, a pressure-sensitive adhesive composition. This pressure-sensitive adhesive composition is not particularly limited, and examples thereof include a composition containing a normal pressure-sensitive adhesive such as acrylic, rubber, and silicone. An acrylic pressure-sensitive adhesive is preferably used from the viewpoint of weather resistance and price.

Examples of the acrylic pressure-sensitive adhesive include a copolymer having a (meth) acrylic acid ester as a constituent component (hereinafter referred to as “(meth) acrylic acid ester copolymer”). Moreover, you may contain the hardening | curing agent mentioned later other than a (meth) acrylic acid ester copolymer.
In the present invention, the (meth) acrylic monomer includes both an acrylic monomer and a methacrylic monomer.

Examples of the (meth) acrylic acid ester that is a constituent of the (meth) acrylic acid ester copolymer include methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, isobutyl, amyl, isoamyl, Hexyl, heptyl, cyclohexyl, 2-ethylhexyl, octyl, isooctyl, nonyl, isononyl, decyl, isodecyl, undecyl, lauryl, tridecyl, tetradecyl, stearyl, octadecyl, dodecyl and the like, preferably 4 to 18 carbon atoms And alkyl acrylate or alkyl methacrylate having a linear or branched alkyl group. These alkyl (meth) acrylates may be used alone or in combination of two or more.
In the constituent components of the (meth) acrylic copolymer, the content of the (meth) acrylic acid ester component is preferably 80% by mass or more, more preferably 90% by mass or more, and more preferably 95 to 99.9% by mass. .

The (meth) acrylic acid ester copolymer may contain components other than the (meth) acrylic acid ester.
Other components include, for example, (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, and carboxyl group-containing monomers such as crotonic acid, maleic anhydride Acid anhydride monomers such as acid and itaconic anhydride, hydroxyl group-containing monomers such as hydroxyalkyl (meth) acrylate (preferably those in which the alkyl (meth) acrylate is substituted with a hydroxy group), styrene sulfonic acid, allyl sulfone Sulfonic acid group-containing mono-acids such as acid, 2- (meth) acrylamide-2-methylpropanesulfonic acid, (meth) acrylamidepropanesulfonic acid, sulfopropyl (meth) acrylate and (meth) acryloyloxynaphthalenesulfonic acid -Phosphoric acid group-containing monomers such as 2-hydroxyethylacryloyl phosphate, (meth) acrylamide, (meth) acrylic acid N-hydroxymethylamide, (meth) acrylic acid alkylaminoalkyl esters (for example, dimethylaminoethyl methacrylate, t -Butylaminoethyl methacrylate), N-vinylpyrrolidone, acryloylmorpholine, vinyl acetate, styrene, acrylonitrile and the like. These structural components may be used alone or in combination of two or more.

In the solid component of the pressure-sensitive adhesive layer 3, the content of the (meth) acrylic copolymer (content converted to a state before reacting with a curing agent or a photopolymerizable compound described later) is preferably 80% by mass or more, 90% by mass or more is more preferable, and 95 to 99.9% by mass is more preferable.

As the curing agent, a curing agent described in JP 2007-146104 A can be used. For example, 1,3-bis (N, N-diglycidylaminomethyl) cyclohexane, 1,3-bis (N, N-diglycidylaminomethyl) toluene, 1,3-bis (N, N-diglycidylaminomethyl) ) Epoxy compounds having two or more epoxy groups in the molecule such as benzene, N, N, N, N′-tetraglycidyl-m-xylenediamine, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate , 1,3-xylylene diisocyanate, 1,4-xylene diisocyanate, diphenylmethane-4,4′-diisocyanate, etc., an isocyanate compound having two or more isocyanate groups in the molecule, tetramethylol-tri-β-aziridini Lupropionate, trimethylol-tri-β-aziridinylpropionate, Examples include aziridin compounds having two or more aziridinyl groups in the molecule, such as limethylolpropane-tri-β-aziridinylpropionate and trimethylolpropane-tri-β- (2-methylaziridine) propionate. . The content of the curing agent may be adjusted according to the desired adhesive strength, and is preferably 0.01 to 10 parts by weight, preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the (meth) acrylic acid ester copolymer. 5 parts by mass is more preferable.

The pressure-sensitive adhesive layer 3 is preferably composed of a radiation curable pressure-sensitive adhesive containing a photopolymerizable compound and a photopolymerization initiator in addition to the above pressure-sensitive adhesive. By containing an adhesive, a photopolymerizable compound, and a photopolymerization initiator, it can be cured by irradiation with radiation (preferably ultraviolet rays), and the adhesive strength of the adhesive layer 3 can be reduced. Examples of such a photopolymerizable compound include those described in JP-A-60-196956 and JP-A-60-223139, which have a photopolymerizable carbon in a molecule that can be three-dimensionally reticulated by light irradiation. A low molecular weight compound having at least two carbon double bonds or an oligomer obtained by polymerizing them can be used.

Specific examples of the photopolymerizable compound include trimethylolpropane tri (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, and dipentaerythritol monohydroxy. Penta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, neopentyl glycol di (meth) acrylate or 1,4-butylene glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, (poly ) Ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, epoxy (meth) acrylate ((meth) acrylic acid adduct of epoxy compound), poly Ester (meth) acrylates (the polyester (meth) acrylic acid adduct), and urethane (meth) acrylate ((meth) acrylic acid adduct of urethane) are used.

As the photopolymerization initiator, the photopolymerization initiators described in JP2007-146104A or JP2004-186429A can be used. Specifically, isopropyl benzoin ether, isobutyl benzoin ether, benzophenone, Michler's ketone, chlorothioxanthone, benzylmethyl ketal, α-hydroxycyclohexyl phenyl ketone, 2-hydroxymethylphenylpropane, and the like can be used.

As the radiation curable pressure-sensitive adhesive, in addition to the combination of the (meth) acrylic acid ester copolymer and a low molecular weight compound having at least two radiation polymerizable carbon-carbon double bonds in the molecule, A copolymer having (meth) acrylic acid ester as a constituent component, wherein the repeating unit constituting the copolymer has a radiation-polymerizable carbon-carbon double bond (hereinafter referred to as “a”). It is also preferable to use “radiation polymerizable (meth) acrylic copolymer”.
The radiation-polymerizable (meth) acrylic copolymer is a copolymer having a reactive group capable of undergoing a polymerization reaction upon irradiation with radiation, particularly ultraviolet rays, in the copolymer molecule.
Such a reactive group is an ethylenically unsaturated group, that is, a group having a carbon-carbon double bond (ethylenically unsaturated bond), such as vinyl group, allyl group, styryl group, (meth) acryloyloxy. Group, (meth) acryloylamino group and the like.

The radiation polymerizable (meth) acrylic copolymer is not particularly limited. For example, the (meth) acrylic copolymer having the functional group a, the functional group b capable of reacting with the functional group a, and radiation. A (meth) acrylic copolymer obtained by reacting a compound having a polymerizable carbon-carbon double bond (hereinafter referred to as “radiation polymerizable compound having a functional group b”) can be given.

Examples of the (meth) acrylic copolymer having a carbon-carbon double bond include the same materials as those described in paragraphs [0036] to [0055] of JP-A-2014-192204. be able to.

In the radiation-polymerizable compound having the functional group b, the functional group b includes a carboxyl group, a hydroxyl group, an amino group, a cyclic acid anhydride group, an epoxy group, an isocyanate group, and the like. Specific examples of the radiation polymerizable compound having a functional group b include acrylic acid, methacrylic acid, cinnamic acid, itaconic acid, fumaric acid, phthalic acid, 2-hydroxyalkyl acrylates, 2-hydroxyalkyl methacrylates, Glycol monoacrylates, glycol monomethacrylates, N-methylolacrylamide, N-methylolmethacrylamide, allyl alcohol, N-alkylaminoethyl acrylates, N-alkylaminoethyl methacrylates, acrylamides, methacrylamides, maleic anhydride Itaconic anhydride, fumaric anhydride, phthalic anhydride, glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, hydroxyl group or a part of the isocyanate group of the polyisocyanate compound Carboxyl group and a radiation-polymerizable carbon - can enumerate such as those urethanization a monomer having a carbon-carbon double bond.

In the reaction between the (meth) acrylic copolymer having the functional group a and the radiation-polymerizable compound having the functional group b, by leaving an unreacted functional group, the acid value and the hydroxyl value can be determined. Can be set as appropriate.
The radiation-polymerizable (meth) acrylic copolymer can be obtained by solution polymerization in various solvents. As the organic solvent in the case of solution polymerization, a ketone, ester, alcohol, or aromatic solvent can be used. In general, it is preferable to use a good solvent for an acrylic polymer and a solvent having a boiling point of 60 to 120 ° C. For example, toluene, ethyl acetate, isopropyl alcohol, benzene, methyl cellosolve, ethyl cellosolve, acetone, methyl ethyl ketone, and the like can be used. As the polymerization initiator, radical generators such as azobis compounds such as α, α′-azobisisobutylnitrile and organic peroxide compounds such as benzoyl peroxide can be used. At this time, if necessary, a catalyst and a polymerization inhibitor can be used in combination, and a copolymer having a desired molecular weight can be obtained by adjusting the polymerization temperature and the polymerization time. The synthesis method is not limited to solution polymerization, and other methods such as bulk polymerization and suspension polymerization may be used.

In addition, the pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer 3 may contain a release agent, a tackifier, a tackifier, a surfactant, or other modifiers as necessary. Moreover, you may contain an inorganic compound filler.

The pressure-sensitive adhesive layer 3 can be formed by applying the pressure-sensitive adhesive composition onto the release film 4, drying it, and transferring it to the substrate 2. In the present invention, the thickness of the pressure-sensitive adhesive layer 3 is preferably 10 to 60 μm, more preferably 20 to 50 μm. If it is too thick, the semiconductor wafer 5 will be peeled off after the adhesive tape 1 for semiconductor processing has been peeled off due to excessive adhesion to the surface of the semiconductor wafer 5 (see FIG. 2) and embedding in the convex portion 51 (see FIG. 2) of the surface of the semiconductor wafer 5. There is a risk of adhesive residue on the surface. By setting it to the upper limit value or less, excessive adhesion of the pressure-sensitive adhesive can be suppressed. If it is too thin, the pressure-sensitive adhesive layer 3 cannot follow the convex portion 51 on the surface of the semiconductor wafer 5, and grinding water containing silicon grinding waste enters through the gap between the semiconductor processing pressure-sensitive adhesive tape 1 and the semiconductor wafer 5. 5 may contaminate the circuit surface of 5 and cause so-called seapage.

(Peeling film 4)
The release film 4 is also called a separator, a release layer, or a release liner, and is provided as necessary for the purpose of protecting the radiation curable pressure-sensitive adhesive layer and for the purpose of smoothing the radiation curable pressure-sensitive adhesive layer. It is done. Examples of the constituent material of the release film 4 include synthetic resin films such as polyethylene, polypropylene, and polyethylene terephthalate, and paper. The surface of the release film 4 may be subjected to release treatment such as silicone treatment, long-chain alkyl treatment, and fluorine treatment as necessary in order to enhance the peelability from the pressure-sensitive adhesive layer 3. Moreover, in order to prevent the reaction by the environmental ultraviolet-ray of the adhesive layer 3, the ultraviolet-ray prevention process may be performed as needed. The thickness of the release film 4 is usually 10 to 50 μm, preferably 25 to 38 μm.

[Method for Manufacturing Semiconductor Device]
The pressure-sensitive adhesive tape for semiconductor processing of the present invention is a semiconductor wafer (hereinafter referred to as “semiconductor wafer A”) in which a modified layer is formed inside a semiconductor wafer by irradiating a laser along a region where each chip is to be separated. Alternatively, a semiconductor wafer (hereinafter referred to as “semiconductor wafer B”) in which a groove is formed by mechanical means along a region where each chip is to be singulated is divided into chips by grinding the back surface of the semiconductor wafer. It is preferably used for manufacturing a semiconductor chip to be (divided).
Here, the “back surface of the semiconductor wafer” means a surface of the semiconductor wafer that is located on the opposite side of the pattern surface on the surface of which the circuit of the semiconductor element is formed. Specifically, the pattern surface is a modified layer forming surface in the semiconductor wafer A and a groove forming surface in the semiconductor wafer B.
“Scheduled area of each chip” means a scribe line of a wafer.
In addition, “divided into chips” means a state where semiconductor chips are separated from a semiconductor wafer, and the separated semiconductor chips are bonded onto the adhesive tape for semiconductor processing of the present invention. Including the state.

The semiconductor wafer A is a semiconductor wafer in which a modified layer is formed inside the semiconductor wafer by irradiating a laser along a region to be singulated of each chip. By laser irradiation, by forming the modified layer of a thickness T _A to the semiconductor wafer 5, the back-side grinding of a subsequent semiconductor wafer, the semiconductor wafer 5 is than or equal the thickness T _A and the thickness T _A By grinding to be thin, the semiconductor wafer 5 can be thinned and separated into semiconductor chips at the same time. The thickness T _A is not particularly limited as long as less than the thickness of back grinding the semiconductor wafer before, it is it is practical than the final thickness of the wafer greater the 20 ~ 30 [mu] m.
This method is a method that combines stealth dicing and tip dicing, and is also called a chip singulation method corresponding to a narrow scribe width. According to this method, the modified layer of silicon (semiconductor wafer) is cleaved and separated by stress during wafer back grinding, so the kerf width is zero, the chip yield is high, and the bending strength is improved. To do.
The semiconductor wafer B is a semiconductor wafer in which a groove is formed by mechanical means along a region to be singulated of each chip. By mechanical means (e.g., a dicing blade), by forming a groove in the thickness T _B to the semiconductor wafer 5, the back-side grinding of a subsequent semiconductor wafer, the semiconductor wafer 5 is equal to or above the aforementioned thickness T _B by grinding to be thinner than the thickness T _B, it is possible to perform thinning of the semiconductor wafer 5 and the pieces of the semiconductor chips at the same time. The thickness T _B is not particularly limited as long as less than the thickness of back grinding the semiconductor wafer before it is is practical than the final thickness of the wafer greater the 20 ~ 30 [mu] m.
This method is called a DBG (first dicing) method. According to this method, although there is a limit to narrowing the width of the kerf (also referred to as a scribe line or street) which is the distance between the chips, it is possible to increase the bending strength of the chip and to suppress the breakage of the chip. .

The semiconductor chip manufacturing method (semiconductor wafer processing method) using the semiconductor processing adhesive tape of the present invention will be described with reference to FIG.
When the adhesive tape 1 for semiconductor processing of this invention has the peeling film 4 on the adhesive layer 3, the peeling film 4 is peeled off and the adhesive layer 3 is exposed, and the base material 2 and the adhesive layer 3 are laminated | stacked. The semiconductor processing adhesive tape 1 is used (see FIG. 2A). The adhesive tape 1 for semiconductor processing of the present invention is bonded to a semiconductor wafer 5 so that the convex portion 51 of the semiconductor wafer 5 and the adhesive layer 3 are in contact with each other, and the convex portion 51 is covered with the adhesive tape 1 for semiconductor processing of the present invention. Obtained semiconductor wafer 5 is obtained (see FIG. 2B). Here, the convex portion 51 means a portion that can constitute a semiconductor chip when separated into pieces in a semiconductor wafer, and usually has a pattern surface on which a circuit of a semiconductor element or the like is formed.

The back surface of the semiconductor wafer 5 is ground by the polishing machine 7 to reduce the thickness of the semiconductor wafer 5 (see FIG. 2C), and finally is separated into semiconductor chips having a pattern surface.
The separated semiconductor chip is picked up from the semiconductor processing pressure-sensitive adhesive tape 1 of the present invention by a conventional method such as peeling with a peeling tape while adsorbed on the chuck table. At this time, when the pressure-sensitive adhesive layer 3 is an ultraviolet curable type, the pressure-sensitive adhesive layer 3 is easily peeled off from the separated semiconductor chip by reducing the adhesive force of the pressure-sensitive adhesive layer 3 by ultraviolet irradiation. It becomes possible.

EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not limited to these.
The density of the resin used below was measured according to JIS K7112, and the MFR of the resin was measured according to JIS K7210 at a temperature of 190 ° C. and a load of 21.18 N.

<Example 1>
1. Preparation of pressure-sensitive adhesive composition 80 parts by mass of 2-ethylhexyl acrylate as an acrylate monomer, 20 parts by mass of 2-hydroxyethyl acrylate as an acrylate monomer having a functional group, and 1 part by mass of methyl methacrylate as constituent components (meth) acrylic The polymer is reacted with 3 parts by mass of 2-isocyanatoethyl methacrylate having an ultraviolet-polymerizable carbon-carbon double bond in the molecule and an isocyanate group that reacts with a hydroxyl group, thereby producing an ultraviolet-polymerizable carbon-carbon double bond. A (meth) acrylic copolymer having the following was obtained. For 100 parts by mass of this copolymer, 0.9 part by mass of an isocyanate compound (trade name: Coronate L, manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent, and a photopolymerization initiator (trade name: Irgacure 184, manufactured by BASF) 5.0 parts by mass was mixed to obtain an ultraviolet curable pressure-sensitive adhesive composition.
2. Preparation of base material A base material having a total thickness of 100 μm, prepared by an extrusion method, in which 25 μm of LLDPE (linear low density polyethylene, metallocene catalyst polymer), 50 μm of COP (cyclic olefin polymer), and 25 μm of LLDPE were laminated in this order. Obtained. Here, the ethylene content of COP was 30% by mass, and the MFR was 0.8 g / 10 min. Further, MFR of LLDPE was 2.5 g / 10 min, and the density was 0.925 g / cm ³ .
3. Preparation of pressure-sensitive adhesive tape for semiconductor processing The pressure-sensitive adhesive composition was applied on a PET film (thickness 25 μm) subjected to a release treatment so that the thickness after drying was 30 μm, dried and then used with a solvent. After evaporating some ethyl acetate, it was bonded to the base material, and the pressure-sensitive adhesive was transferred to the base material side to obtain a pressure-sensitive adhesive tape for semiconductor processing according to Example 1. As shown in FIG. 1, the semiconductor processing pressure-sensitive adhesive tape 1 has a structure in which a base film 2, a pressure-sensitive adhesive layer 3, and a release film 4 are laminated in this order. Furthermore, the substrate film 2 includes sequentially from the pressure-sensitive adhesive layer 3 side, the layer B _1, a layer A, a structure in which the layer B ₂ are laminated in this order.

<Example 2>
A semiconductor processing pressure-sensitive adhesive tape according to Example 2 was obtained in the same manner as in Example 1 except that LLDPE was changed to LLDPE (metallocene catalyst polymer) having an MFR of 4 g / 10 min.

<Example 3>
A pressure-sensitive adhesive tape for semiconductor processing according to Example 3 was obtained in the same manner as in Example 2 except that the thickness of the substrate was changed to 150 μm in total thickness of LLDPE 35 μm, COP 80 μm, and LLDPE 35 μm.

<Example 4>
LLDPE was changed to HDPE with MFR of 7.0 g / 10 min and density of 0.964 g / cm ³ , except that COP was changed to COP with ethylene content of 35% by mass and MFR of 2.0 g / 10 min. A semiconductor processing pressure-sensitive adhesive tape according to Example 4 was obtained in the same manner as in Example 1.

<Example 5>
Adhesion for semiconductor processing according to Example 5 except that LLDPE was changed to LLDPE (metallocene catalyst polymer) having an MFR of 2.0 g / 10 min and a density of 0.918 g / cm ^3. I got a tape.

<Example 6>
Example 1 except that LLDPE was changed to LLDPE with MFR of 4.0 g / 10 min and density of 0.944 g / cm ³ , and the thickness of the base material was changed to LLDPE of 16 μm, COP of 48 μm, and LLDPE of 16 μm, total thickness of 80 μm. By the same method, the adhesive tape for semiconductor processing which concerns on Example 6 was obtained.

<Comparative Example 1>
A pressure-sensitive adhesive tape for semiconductor processing according to Comparative Example 1 was obtained in the same manner as in Example 1 except that LLDPE was changed to LDPE having an MFR of 3.1 g / 10 min and a density of 0.925 g / cm ³ .

<Comparative example 2>
A pressure-sensitive adhesive tape for semiconductor processing according to Comparative Example 2 was obtained in the same manner as in Comparative Example 1 except that the COP was changed to a COP having an ethylene content of 35% by mass and an MFR of 2.0 g / 10 min.

<Comparative Example 3>
Adhesive tape for semiconductor processing according to Comparative Example 3, except that LLDPE was changed to an ethylene vinyl acetate copolymer having an MFR of 2.5 g / 10 min and a density of 0.928 g / cm ^3. Got.

The following evaluation was performed about the obtained adhesive tape for semiconductor processing.

[1. Interlayer adhesion]
A film having a length of 1300 mm, a width of 25 mm, and a thickness of 100 μm was prepared using the resin constituting the layers B ₁ and B ₂ and the resin constituting the layer A, respectively. An area of 25 mm × 10 mm of the two types of produced films was overlapped and thermocompression bonded at 220 ° C. for 5 seconds to form a joint. The peel strength when peeled at a speed of 300 mm / min and a peel angle of 180 ° was measured with a strograph (manufactured by Toyo Seiki). The peel strength of 5N or more was evaluated as “◯”, and the peel strength of less than 5N was evaluated as “x”.

[2. Heat-resistant]
The adhesive layer side of each tape of the adhesive tape for semiconductor processing according to Examples and Comparative Examples is bonded to a 8-inch dummy wafer having a smooth surface, and the wafer is bonded using a disco grinder DGP8760 (trade name). Grinding to a thickness of 50 μm. After grinding, the tape side was heated to 70 ° C. with the hot plate so as to be in contact with the hot plate, and “◯” was evaluated when there was no change in appearance, and “X” when there was a change.

[3. Peelability]
The adhesive tape for semiconductor processing (hereinafter referred to as “adhesive tape”) produced above was bonded to an 8-inch dummy wafer, and the wafer was ground to a thickness of 50 μm using a disco grinder DGP8760 (trade name). . After grinding, using a high-pressure mercury lamp from the adhesive tape side, irradiate ultraviolet rays with an integrated irradiation amount of 500 mJ / cm ² to cure the adhesive layer and reduce the adhesive force, then with the adhesive tape surface facing up It was adsorbed on the chuck table, and the adhesive tape was peeled off using a peeling tape (manufactured by Nitto Denko Corporation). What was peeled off at the interface between the wafer and the pressure-sensitive adhesive layer was evaluated as “◯”, and those that could not be peeled off or peeled off at other locations were evaluated as “x”.

[4. crack]
An 8-inch dummy wafer (thickness: 725 μm) formed with a groove of 75 μm depth along the planned individualization area with a chip size of 10 mm long × 12 mm wide (hereinafter referred to as an adhesive tape for semiconductor processing) , Referred to as an adhesive tape) was bonded on the surface side where the grooves were formed, and the wafer was ground to a thickness of 50 μm using a disco grinder DGP8760 (trade name) to separate the chips. After grinding, use a high-pressure mercury lamp from the adhesive tape side to irradiate ultraviolet rays with an integrated irradiation amount of 500 mJ / cm ² to cure the adhesive layer and reduce the adhesive force, and then peel off each chip from the adhesive tape. The cracks at the end of the chip were observed with a microscope. When the number of cracked chips was 10 or less, “◯” was evaluated, 10 to 20 were evaluated as “Δ”, and 20 or more were evaluated as “X”.

From Table 1 above, Examples 1 to 6, which are adhesive tapes for semiconductor processing specified in the present invention, showed good results in all of heat resistance, peelability, interlayer adhesion, and suppression of crack generation. On the other hand, the adhesive tape for semiconductor processing of Comparative Examples 1 and 2 was inferior in peelability and interlayer adhesion, and the adhesive tape for semiconductor processing in Comparative Example 3 was inferior in interlayer adhesion.

While this invention has been described in conjunction with its embodiments, we do not intend to limit our invention in any detail of the description unless otherwise specified and are contrary to the spirit and scope of the invention as set forth in the appended claims. I think it should be interpreted widely.

This application claims priority based on Japanese Patent Application No. 2017-046435 filed in Japan on March 10, 2017, which is hereby incorporated herein by reference. Capture as part.

DESCRIPTION OF SYMBOLS 1 Adhesive tape for semiconductor processing 2 Base material 3 Adhesive layer 4 Release film 5 Semiconductor wafer 7 Polishing machine 51 Convex part

Claims

A pressure-sensitive adhesive tape comprising a base material and a pressure-sensitive adhesive layer provided on one side of the base material, wherein the base material has a multi-layer structure, and at least one layer of the multi-layer structure is composed of 80 masses of a cyclic olefin polymer. % Of layer A, and a layer B containing linear low-density polyethylene or high-density polyethylene separately from the layer A, a pressure-sensitive adhesive tape for semiconductor processing.
The pressure-sensitive adhesive tape for semiconductor processing according to claim 1, wherein the density of the linear low-density polyethylene is 0.95 g / cm 3 or less.
The pressure-sensitive adhesive tape for semiconductor processing according to claim 1 or 2, wherein the linear low-density polyethylene has a melt flow rate of 4.0 g / 10 min or less.
The pressure-sensitive adhesive tape for semiconductor processing according to any one of claims 1 to 3, wherein the linear low-density polyethylene is metallocene polyethylene.
A semiconductor wafer in which a modified layer is formed inside the semiconductor wafer by irradiating a laser along the individual separation area of each chip, or a groove is formed by mechanical means along the individual separation area of each chip. The pressure-sensitive adhesive tape for semiconductor processing according to any one of claims 1 to 4, wherein the pressure-sensitive adhesive tape is used for manufacturing a semiconductor chip in which a semiconductor wafer is divided into chips by grinding the back surface of the semiconductor wafer.