CN110073470B

CN110073470B - Adhesive tape for semiconductor processing

Info

Publication number: CN110073470B
Application number: CN201880005072.1A
Authority: CN
Inventors: 内山具朗; 五岛裕介
Original assignee: Furukawa Electric Co Ltd
Current assignee: Furukawa Electric Co Ltd
Priority date: 2017-03-10
Filing date: 2018-03-07
Publication date: 2023-10-17
Anticipated expiration: 2038-03-07
Also published as: TWI705119B; SG11201907365RA; KR20190085059A; WO2018164175A1; JP6667468B2; JP2018152420A; TW201833276A; MY197838A; KR102267114B1; CN110073470A

Abstract

A tape for semiconductor processing comprising a base material and an adhesive layer provided on one side of the base material, wherein the base material is composed of a multilayer structure, at least 1 layer of the multilayer structure is a layer A containing 80 mass% or more of a cyclic olefin polymer, and a layer B containing a linear low-density polyethylene or a high-density polyethylene is provided in addition to the layer A.

Description

Adhesive tape for semiconductor processing

Technical Field

The present application relates to a semiconductor processing tape, and more particularly, to a semiconductor processing tape used in processing a semiconductor wafer, and more particularly, to a semiconductor processing surface protection tape suitable for use in a method of manufacturing semiconductor chips that are singulated into chips by back grinding of a semiconductor wafer.

Background

In a process of manufacturing a semiconductor wafer (hereinafter also referred to as a wafer), after patterning a wafer surface, so-called back grinding and polishing, which grinds and grinds the wafer back to a specific thickness, are performed. At this time, a surface protective tape is attached to the wafer surface to protect the wafer surface, and the wafer back surface is ground in this state. As a surface protective tape, a surface protective tape provided with an adhesive layer containing an acrylic polymer as a main component on a plastic film such as polyolefin has been proposed (for example, see patent document 1).

On the other hand, with the popularization of IC cards, coping with the rapid increase in capacity of semiconductor memories typified by USB memories, and the popularization of small devices such as smart phones and tablet computers, further thinning of chips is demanded. For example, a chip having a conventional thickness of about 200 μm to 350 μm is required to be thinned to a thickness of 50 μm to 100 μm or less.

Generally, a wafer on which a circuit pattern is formed is thinned by a back grinding process. The film-like wafer after grinding is liable to be bent (hereinafter referred to as warp) due to the shrinkage difference of silicon and circuits, the protective layer, and shrinkage of the tape. The thinner the chip is, the less the rigidity of the wafer itself is, and thus the following problems arise: warpage occurs which makes wafer transfer or processing within the apparatus impossible.

If the final thickness of the wafer after back grinding is 100 μm or less, the strength of the wafer is lowered, and cracks may occur starting from a slight impact or defect, which may reduce the yield. In addition, even if no crack is generated in the back grinding, the chip is mechanically cut by the diamond blade in the subsequent chip singulation (hereinafter referred to as dicing) process, and thus there is also a case where the chip is broken due to a defect (hereinafter referred to as chip) generated from the dicing line.

Regarding the processing of the thin film wafer described above, for example, patent document 2 proposes a wafer dividing method in which grooves having a depth greater than a final predetermined wafer thickness and less than an original wafer thickness are formed by dicing from a wafer circuit side at predetermined positions (chip dividing predetermined positions) before back grinding, and then the grooves are thinned to a depth equal to or greater than the groove depth by back grinding, and back grinding and chip formation are performed simultaneously.

As a method similar to the above, for example, patent document 3 proposes a laser processing method in which a modified layer is formed in a wafer instead of a groove by irradiating a chip at a predetermined position for chip division, and the chip is divided and chipped from the modified layer at the time of back grinding. With this method, since no conventional groove is present, the distance between chips can be made almost zero, and more chips can be obtained from one wafer. In addition, the cutting impact caused by the diamond blade is not present, so that the fragments can be eliminated.

Prior art literature

Patent literature

Patent document 1: japanese patent application laid-open No. 2001-240842

Patent document 2: japanese patent laid-open No. 11-40520

Patent document 3: japanese patent laid-open No. 2002-192370

Disclosure of Invention

Problems to be solved by the application

On the other hand, in the method described in patent document 3, since the modified layer is formed by laser light, the inter-chip distance is almost 0, and if chips are displaced by external factors such as deformation of the surface protective tape or shearing force at the time of back grinding, there is a problem that the chips are likely to come into contact with adjacent chips, and cracks are likely to occur from the parts.

Further, as a result of intensive studies, the present inventors have found that, when a substrate having a multilayer structure with a specific layer is used as a substrate for a tape, adhesion between layers constituting the multilayer structure is important, and if the adhesion between layers is insufficient, peeling properties are lowered, or interlayer peeling occurs during processing of a semiconductor wafer as an adherend, resulting in breakage of the wafer.

Accordingly, an object of the present application is to solve the above-described problems and provide a semiconductor processing tape which is excellent in peelability and interlayer adhesiveness even when ground into a thin film in a process of processing a semiconductor wafer, particularly in a back grinding process of a silicon wafer or the like, and which can sufficiently suppress occurrence of defective chips.

Means for solving the problems

The above-described problems of the present application are solved by the following means.

(1)

(2)

The adhesive tape for semiconductor processing according to (1), wherein the linear low-density polyethylene has a density of 0.95g/cm ³ The following is given.

(3)

The adhesive tape for semiconductor processing according to (1) or (2), wherein the linear low-density polyethylene has a melt flow rate of 4.0g/10min or less.

(4)

The adhesive tape for semiconductor processing according to any one of (1) to (3), wherein the linear low-density polyethylene is a metallocene polyethylene.

(5)

The adhesive tape for semiconductor processing according to any one of (1) to (4), which is used for manufacturing a semiconductor chip, wherein the semiconductor chip is manufactured by dividing a semiconductor wafer into chips by grinding the back surface of the semiconductor wafer, and the semiconductor wafer is a semiconductor wafer in which a modified layer is formed inside the semiconductor wafer by irradiating laser light along a predetermined dividing region of each chip or a semiconductor wafer in which a groove is formed by mechanical means along a predetermined dividing region of each chip.

ADVANTAGEOUS EFFECTS OF INVENTION

The adhesive tape for semiconductor processing of the present application is excellent in peelability and interlayer adhesion even when it is ground into a film in a process of processing a semiconductor wafer, particularly in a back grinding process of a silicon wafer or the like, and further can sufficiently suppress occurrence of defective chips.

The tape for semiconductor processing according to the present application is used for a method for manufacturing semiconductor chips, in which chips are singulated by back grinding of a semiconductor wafer, and therefore, even if the tape is ground into a thin film, the tape is excellent in peelability and interlayer adhesiveness, and further, occurrence of defective chips can be sufficiently suppressed.

The above and other features and advantages of the present application will be further apparent from the following description with reference to the accompanying drawings as appropriate.

Drawings

Fig. 1 is a schematic cross-sectional view schematically showing one embodiment of the tape for semiconductor processing of the present application.

Fig. 2 (a) to 2 (c) are schematic cross-sectional views for explaining a process for processing a semiconductor wafer using the tape for semiconductor processing of the present application. Fig. 2 (a) shows a step of peeling the release film from the semiconductor processing tape to expose the adhesive layer, fig. 2 (b) shows a state in which the semiconductor processing tape is attached to the convex portion side of the semiconductor wafer, and fig. 2 (c) shows a step of grinding the back surface of the semiconductor wafer.

Detailed Description

[ adhesive tape for semiconductor processing ]

The adhesive tape for semiconductor processing of the present application is an adhesive tape comprising a base material and an adhesive layer provided on one side of the base material, wherein the base material is composed of a multilayer structure, and at least 1 layer of the multilayer structure is a layer A containing 80 mass% or more of a cyclic olefin polymer, and a layer B containing a linear low-density polyethylene or a high-density polyethylene is provided in addition to the layer A.

Hereinafter, a preferred embodiment of the tape for semiconductor processing of the present application will be described.

As shown in fig. 1, a tape 1 for semiconductor processing according to the present application is a tape in which an adhesive layer 3 is laminated on a base material 2, and two layers are integrated. The adhesive tape 1 for semiconductor processing may further include a release film 4 for protecting the adhesive layer 3 on the adhesive layer 3. The adhesive tape 1 for semiconductor processing of the present application may be formed by rolling a laminate of the base material 2, the adhesive layer 3 and the release film 4 into a roll.

(substrate 2)

The base material 2 of the adhesive tape 1 for semiconductor processing of the present application is constituted by a multilayer structure. At least 1 layer of the multilayer structure is a layer a containing a cyclic olefin polymer (hereinafter referred to as "COP"), and a layer B containing a linear low density polyethylene or a high density polyethylene is provided as at least 1 layer of the multilayer structure in addition to the layer a.

In the present specification, COP means a ring-opened polymer of a cyclic olefin or a hydrogen adduct thereof, an addition polymer of a cyclic olefin, and also includes an addition copolymer of a cyclic olefin and a chain olefin, which is called a cyclic olefin copolymer (hereinafter referred to as "COC").

The cyclic olefin as a monomer may be a cyclic olefin or alkyne, as long as it is a compound capable of forming a polymer by ring-opening polymerization or addition polymerization. The number of carbon atoms is preferably 4 to 12. The cyclic olefin may contain a bicyclic olefin, and may further contain a monocyclic olefin and/or a polycyclic olefin having at least three rings. Examples of the monocyclic olefins include cyclic cycloolefins having 4 to 12 carbon atoms such as cyclobutene, cyclopentene, cycloheptene, and cyclooctene. Examples of the polycyclic olefins having two or more rings include dicyclopentadiene; derivatives of 2, 3-dihydro-dicyclopentadiene, methano-octahydrofluorene, methano-octahydronaphthalene, methano-dimethano-cyclopentadiene naphthalene, methano-octahydro-cyclopentadiene naphthalene, and the like; derivatives having a substituent such as 6-ethyloctahydronaphthalene; adducts of cyclopentadiene with tetrahydroindene and the like, 3 to 4 polymers of cyclopentadiene, norbornene, tetracyclododecene and the like, norbornene and tetracyclododecene are preferable.

The chain olefin may be a chain olefin or an alkyne, as long as the chain olefin is a compound capable of forming 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 still more preferably 2 to 4. Specifically, examples thereof include chain olefins having 2 to 10 carbon atoms such as ethylene, propylene, 1-butene, isobutylene, 1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-hexene and 1-octene. These chain olefins may be used alone or in combination of two or more, and ethylene is particularly preferred.

In the layer a, the COP content is 80 mass% or more, preferably 90 mass% or more. The upper limit is not particularly limited, but is 100 mass% or less. When COP is COC, the COP content refers to the COC content.

Specific examples of the COP include "ZEONOR" manufactured by Zeon corporation and "Topas" manufactured by Polyplastics corporation.

In COP, a homopolymer of a cyclic olefin is an amorphous resin, has hard and brittle properties, and requires high-temperature treatment even when a sheet or film is formed.

On the other hand, COC is a copolymer of a cyclic olefin and ethylene, and thus has flexibility and ductility. Further, COC having various characteristics can be obtained by adjusting the polymerization ratio (content ratio).

The ethylene component content in the constituent components of COC is preferably 30 to 40 mass%, more preferably 35 to 40 mass%. If the ethylene content is too small, the substrate becomes very brittle, and the semiconductor processing tape may break. In addition, if the ethylene component content is too large, the properties of the ethylene component become strong, and there is a possibility that sufficient rigidity cannot be obtained.

The substrate 2 has, as a layer other than the COP-containing layer a, a layer B which has good adhesion to the layer a and contains a linear low density polyethylene (hereinafter referred to as "LLDPE") or a high density polyethylene (hereinafter referred to as "HDPE"). Low-density polyethylene (hereinafter referred to as "LDPE") is not preferable in view of the inability to obtain sufficient interlayer adhesion to layer a. If the interlayer adhesion is insufficient, the peeling property is insufficient, and there is a possibility that interlayer peeling may occur during processing of the semiconductor wafer as an adherend, and the wafer may be broken.

LLDPE and HDPE can be copolymers of ethylene with alpha-olefins. The α -olefin is preferably an α -olefin having 3 to 10 carbon atoms, and examples thereof include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, and 1-octene.

When the LLDPE and the HDPE are copolymers of ethylene and an alpha-olefin, the content of the ethylene component is preferably 95 to 99% by mass, more preferably 96 to 98% by mass, based on the total components of the copolymer.

In the layer B, the content of LLDPE and HDPE is preferably 50 mass% or more, more preferably 80 mass% or more. The upper limit is not particularly limited, but is 100 mass% or less. In the case where LLDPE and HDPE are copolymers of ethylene and an alpha-olefin, the content of LLDPE and HDPE is the content of the copolymer of ethylene and an alpha-olefin.

The LLDPE preferably has a density of 0.95g/cm ³ Hereinafter, more preferably 0.94g/cm ³ Hereinafter, it is more preferably 0.93g/cm ³ The following is given. The lower limit is practically 0.89g/cm ³ The above.

The Melt Flow Rate (MFR) of LLDPE is preferably 4.0g/10min or less, more preferably 2.0g/10min or less, still more preferably 1.0g/10min or less. The lower limit is practically 0.5g/10min or more.

Further, the density of HDPE is preferably 0.97g/cm ³ Hereinafter, more preferably 0.96g/cm ³ The following is given. The lower limit is practically 0.5g/cm ³ The above.

The HDPE has a MFR (melt flow rate) content of preferably 6.0g/10min or less, more preferably 5.0g/10min or less. The lower limit is practically 0.5g/10min or more.

The MFR was a value at 190℃under a load of 21.18N, and the density and MFR were measured by the methods described in the examples.

The LLDPE is particularly preferably a metallocene polyethylene in view of adhesion to the layer A containing COC.

In the present specification, the term "metallocene polyethylene" means an ethylene-based polyolefin obtained using a metallocene catalyst (hereinafter sometimes referred to as "metallocene catalyst ethylene-based polyolefin") obtained by polymerizing ethylene or a mixed monomer of ethylene and an α -olefin in the presence of a metallocene catalyst. Thus, the ethylene-based polyolefin obtained using the metallocene catalyst includes polyethylene obtained by polymerization in the presence of the metallocene catalyst, and a copolymer of ethylene and α -olefin.

The metallocene catalyst is a generic term for a catalyst comprising a transition metal component formed from a complex of a metallocene, that is, 2 substituted or unsubstituted cyclopentadienyl rings, and various transition metals, and an organoaluminum component, particularly, an aluminoxane. Examples of the transition metal component include metals of group IVb, group Vb or group VIb of the periodic Table, particularly zirconium or hafnium. As the transition metal component in the catalyst, generally, a catalyst generally represented by the following formula is used

(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).

As the aluminoxane, there are linear aluminoxane and cyclic aluminoxane, which are obtained by reacting an organoaluminum compound with water. These aluminoxanes may be used alone or in combination with other organoaluminum compounds.

The polymerization of ethylene or ethylene with an α -olefin using a metallocene catalyst is known in many publications, and the polymerization is synthesized by polymerization in an organic solvent, in a liquid monomer or in a gas phase method in the presence of the above metallocene catalyst, and a substance satisfying the above conditions can be used for the purpose of the present application as well as a substance obtained by any of these known methods.

In the case of a copolymer of ethylene and an α -olefin, the ethylene component content in the entire constituent components of the specific α -olefin and copolymer can be preferably as described in the above-mentioned copolymer of ethylene and α -olefin in LLDPE.

The metallocene catalyst ethylene polyolefin is characterized by a narrow molecular weight distribution, and in the present application, a material having a polydispersity (weight average molecular weight Mw/number average molecular weight Mn) as an index of the molecular weight distribution of preferably 4.0 or less, more preferably 3.5 or less, and still more preferably 3.2 or less is used. In order to improve moldability, it is also preferable to use a material in which a relatively long chain branch is introduced during or after polymerization. In addition, metallocene catalyst ethylene-based polyolefins generally have a density of 0.89g/cm ³ ～0.95g/cm ³ Preferably 0.91g/cm ³ ～0.93g/cm ³ The MFR is about 0.1g/10 min to 10g/10 min, preferably about 0.3g/10 min to 5g/10 min.

The presence of the metallocene catalyst ethylene polyolefin in the layer B can be confirmed by the following method. That is, the layer B was cut into a thickness of 100 μm by glass and laid down in a scanning electron microscope SEM as a sample, and the fluorescence X-rays generated were measured by an analyzer for energy distribution to confirm the presence of a peak corresponding to the energy of Zr (zirconium) or Hf (hafnium).

The metallocene catalyst may be used as a synthetic product or may be selected from commercially available products. Commercially available products include Umerit (registered trademark) manufactured by Umerits, sumitomo chemical Co., ltd., EXCELLEN (registered trademark) manufactured by Sumitomo chemical Co., ltd., harmorex (registered trademark) manufactured by Japanese polyethylene Co., ltd., kernel (registered trademark), and the like.

The LLDPE and HDPE are soft, and therefore have good cushioning properties when wafer grinding. In addition, the melting point of the resin is preferably 60℃or higher from the viewpoint of heat resistance.

Each resin may be used alone as a layer constituting the base material 2, or may be used in combination with each other and blended. In addition to the above resin, the layer constituting the base material 2 may contain additives such as a colorant, an antioxidant, and an antistatic agent as needed within a range not affecting physical properties.

The thickness of the base material 2 is not particularly limited, but is preferably 50 μm to 200 μm, and more preferably 80 μm to 180 μm.

The thickness of the layer A is preferably 20 μm to 100 μm, more preferably 30 μm to 60 μm, from the viewpoint of rigidity. The thickness of the layer B is preferably 10 μm to 100 μm, more preferably 20 μm to 80 μm, from the viewpoint of flexibility.

When the substrate 2 has 2 or more layers a and 2 or more layers B, the "thickness of the layer a" and the "thickness of the layer B" refer to the total thickness of the layers.

The layer structure of the substrate 2 is not particularly limited as long as it is a multilayer structure including at least 1 layer of layers a and B, and is preferably a layer structure in which a layer a and a layer B are laminated adjacently, and more preferably a layer B ₁ Layer A/layer B ₂ More preferably, layer B is formed by sequentially stacking 3 or more layers ₁ Layer A/layer B ₂ And 3 layers laminated in turn. Here, layer B ₁ And layer B ₂ The layers B may be the same layers or different layers.

On the surface of the substrate 2 on the side where the adhesive layer 3 is provided, in order to improve adhesion to the adhesive layer 3, a treatment such as corona treatment or an undercoat layer may be appropriately performed.

The method for producing the base material 2 is not particularly limited. The production can be carried out by extrusion, inflation, casting and other information. The substrate 2 may be formed by bonding a film formed separately with another film using an adhesive or the like.

(adhesive layer 3)

The adhesive layer 3 of the adhesive tape 1 for semiconductor processing of the present application may be any layer containing an adhesive, and is formed using an adhesive composition, for example. The pressure-sensitive adhesive composition is not particularly limited, and typical pressure-sensitive adhesive compositions include acrylic, rubber, silicone, and the like. Acrylic adhesives are preferably used in view of weather resistance, price, etc.

As the acrylic pressure-sensitive adhesive, a copolymer having a (meth) acrylic acid ester as a constituent (hereinafter referred to as a "(meth) acrylic acid ester copolymer") can be exemplified. In addition, a curing agent described later may be contained in addition to the (meth) acrylate copolymer.

In the present application, (meth) acrylic monomers include both acrylic monomers and methacrylic monomers.

Examples of the (meth) acrylic acid ester which is a constituent of the (meth) acrylic acid ester copolymer include alkyl acrylates or methacrylates having a linear or branched alkyl group having 30 or less carbon atoms, preferably having 4 to 18 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, isobutyl, pentyl, isopentyl, hexyl, heptyl, cyclohexyl, 2-ethylhexyl, octyl, isooctyl, nonyl, isononyl, decyl, isodecyl, undecyl, lauryl, tridecyl, tetradecyl, stearyl, octadecyl and dodecyl. These alkyl (meth) acrylates may be used alone or in combination of two or more.

The content of the (meth) acrylic acid ester component in the constituent component of the (meth) acrylic copolymer is preferably 80% by mass or more, more preferably 90% by mass or more, and still more preferably 95% by mass to 99.9% by mass.

The (meth) acrylate copolymer may contain components other than the (meth) acrylate.

Examples of the other constituent components include carboxyl group-containing monomers such as (meth) acrylic acid, carboxyethyl (meth) acrylate, carboxypentyl (meth) acrylate, itaconic acid, maleic acid, fumaric acid, and butenoic acid, hydroxyl group-containing monomers such as maleic anhydride and itaconic anhydride, hydroxyl group-containing monomers such as hydroxyalkyl (meth) acrylates (preferably, those obtained by substituting the above alkyl (meth) acrylates with hydroxyl groups), styrenesulfonic acid, allylsulfonic acid, 2- (meth) acrylamide-2-methylpropanesulfonic acid, (meth) acrylamidopropane sulfonic acid, sulfonic group-containing monomers such as sulfopropyl (meth) acrylate and (meth) acryloxynaphthalene sulfonic acid, and phosphate group-containing monomers such as 2-hydroxyethyl acryloyl phosphate, (meth) acrylamide, N-methylolamide (meth) acrylate, alkylaminoalkyl (e.g., dimethylaminoethyl methacrylate, t-butylaminoethyl methacrylate, and the like), N-vinylpyrrolidone, acryloylmorpholine, vinyl acetate, styrene, acrylonitrile, and the like. These components may be used alone or in combination of two or more.

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

As the curing agent, the one described in JP-A2007-146104 can be used. Examples thereof include an epoxy compound having 2 or more epoxy groups in the molecule such as 1, 3-bis (N, N-diglycidyl aminomethyl) cyclohexane, 1, 3-bis (N, N-diglycidyl aminomethyl) toluene, 1, 3-bis (N, N-diglycidyl aminomethyl) benzene, N '-tetraglycidyl m-xylylenediamine, an aziridine compound having 2 or more aziridine groups in the molecule such as 2, 4-toluene diisocyanate, 2, 6-toluene diisocyanate, 1, 3-xylylene diisocyanate, 1, 4-xylene diisocyanate, diphenylmethane-4, 4' -diisocyanate, and the like, and an aziridine compound having 2 or more aziridine groups in the molecule such as tetramethyl-tri- β -aziridinyl propionate, trimethylol-tri- β -aziridinyl propionate, and trimethylol-propane-tri- β - (2-methylaziridinyl) propionate. The content of the curing agent may be adjusted according to the desired adhesive force, and is preferably 0.01 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, based on 100 parts by mass of the (meth) acrylate copolymer.

In addition to the above-described adhesive, the adhesive layer 3 is preferably composed of a radiation curable adhesive containing a photopolymerizable compound and a photopolymerization initiator. By containing the adhesive, the photopolymerizable compound, and the photopolymerization initiator, the adhesive force of the adhesive layer 3 can be reduced by curing by irradiation of radiation (preferably ultraviolet rays). Examples of such photopolymerizable compounds include low-molecular-weight compounds having at least 2 or more photopolymerizable carbon-carbon double bonds in the molecule, which can be three-dimensionally reticulated by light irradiation as described in JP-A-60-196956 and JP-A-60-223139, and oligomers obtained by polymerizing these compounds.

As the photopolymerizable compound, trimethylolpropane tri (meth) acrylate, pentaerythritol di (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol monohydroxypenta (meth) acrylate, dipentaerythritol hexa (meth) acrylate, neopentyl glycol di (meth) acrylate or 1, 4-butanediol di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) acrylate, epoxy (meth) acrylate (a (meth) acrylic acid adduct of an epoxy compound), polyester (meth) acrylate (a (meth) acrylic acid adduct of a polyester), urethane (meth) acrylate (a (meth) acrylic acid adduct of a urethane) and the like are specifically used.

As the photopolymerization initiator, those described in JP-A2007-146104 or JP-A2004-186429 can be used. Specifically, isopropyl benzoin ether, isobutyl benzoin ether, benzophenone, michaelketone, chlorothioxanthone, benzyl methyl ketal, α -hydroxycyclohexyl phenyl ketone, 2-hydroxymethylphenyl propane, and the like can be used.

As the radiation curable adhesive, in addition to the combination of the above (meth) acrylate copolymer and a low molecular weight compound having at least 2 or more radiation polymerizable carbon-carbon double bonds in the molecule, a (meth) acrylic copolymer (hereinafter referred to as "radiation polymerizable (meth) acrylic copolymer") which is a copolymer having a (meth) acrylate as a constituent component and a repeating unit constituting the copolymer having a radiation polymerizable carbon-carbon double bond is also preferably used.

The radiation-polymerizable (meth) acrylic copolymer is a copolymer having a reactive group capable of undergoing polymerization reaction by irradiation with radiation, particularly ultraviolet rays, in the molecule of the copolymer.

Such a reactive group is an ethylenically unsaturated group, that is, a group having a carbon-carbon double bond (ethylenically unsaturated bond), and examples thereof include a vinyl group, an allyl group, a styryl group, a (meth) acryloyloxy group, and a (meth) acryloylamino group.

The radiation-polymerizable (meth) acrylic copolymer is not particularly limited, and examples thereof include (meth) acrylic copolymers obtained by reacting a (meth) acrylic copolymer having a functional group a with a compound having a functional group b capable of reacting with the functional group a and a radiation-polymerizable carbon-carbon double bond (hereinafter referred to as "radiation-polymerizable compound having a functional group b").

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-A2014-192204.

In the radiation polymerizable compound having the functional group b, the functional group b may include 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 the functional group b include acrylic acid, methacrylic acid, cinnamic acid, itaconic acid, fumaric acid, phthalic acid, 2-hydroxyalkyl acrylates, 2-hydroxyalkyl methacrylates, ethylene glycol monoacrylates, ethylene glycol monomethacrylates, N-methylolacrylamide, N-methylolmethacrylamide, allyl alcohol, N-alkylaminoethyl acrylate, N-alkylaminoethyl methacrylate, acrylamides, methacrylamides, maleic anhydride, itaconic anhydride, fumaric anhydride, phthalic anhydride, glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, and a compound obtained by urethanizing a part of the isocyanate groups of a polyisocyanate compound with a monomer having a hydroxyl group or a carboxyl group and a radiation polymerizable 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, the acid value, the hydroxyl value, and the like can be appropriately set by leaving unreacted functional groups.

The radiation-polymerizable (meth) acrylic copolymer can be obtained by solution polymerization in various solvents. As the organic solvent used in the solution polymerization, ketone-based, ester-based, alcohol-based, and aromatic-based organic solvents can be used. It is preferable to use a solvent which is usually a good solvent for the acrylic polymer and has a boiling point of 60 to 120 ℃. 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, a radical initiator such as an azo-bis-system such as α, α' -azobisisobutyronitrile and an organic peroxide system such as benzoyl peroxide can be used. In this case, a catalyst and a polymerization inhibitor may be used in combination as needed, 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 may be bulk polymerization, suspension polymerization, or other methods.

In addition, the pressure-sensitive adhesive composition constituting the pressure-sensitive adhesive layer 3 may contain a release agent, a tackifier, an adhesion regulator, a surfactant, or other modifier, as necessary. In addition, an inorganic compound filler may be contained.

The adhesive layer 3 may be formed by applying the adhesive composition onto the release film 4 and drying it, transferring it to the substrate 2. In the present application, the thickness of the adhesive layer 3 is preferably 10 μm to 60 μm, more preferably 20 μm to 50 μm. If the thickness is too large, the adhesive residue may be generated on the surface of the semiconductor wafer 5 after the peeling of the tape 1 for semiconductor processing due to the excessive adhesion to the surface of the semiconductor wafer 5 (see fig. 2) and the insertion into the convex portion 51 (see fig. 2) on the surface of the semiconductor wafer 5. By setting the upper limit value or less, excessive adhesion of the adhesive can be suppressed. If the pressure-sensitive adhesive layer 3 is too thin, the pressure-sensitive adhesive layer cannot follow the convex portions 51 on the surface of the semiconductor wafer 5, and grinding water containing silicon chips may enter from the gap between the semiconductor processing tape 1 and the semiconductor wafer 5, and contaminate the circuit surface of the semiconductor wafer 5, that is, so-called seepage (seal) may be caused.

(Release film 4)

The release film 4 is also called a separator, a release layer, or a release liner, and is provided as necessary to protect the radiation curable adhesive layer and to smooth the radiation curable adhesive layer. Examples of the constituent material of the release film 4 include a synthetic resin film such as polyethylene, polypropylene, and polyethylene terephthalate, paper, and the like. In order to improve the releasability from the pressure-sensitive adhesive layer 3, the surface of the release film 4 may be subjected to a release treatment such as silicone treatment, long-chain alkyl treatment, or fluorine treatment, as necessary. In addition, if necessary, ultraviolet ray shielding treatment may be performed to prevent a reaction of the pressure-sensitive adhesive layer 3 due to environmental ultraviolet rays. The thickness of the release film 4 is usually 10 μm to 50. Mu.m, preferably 25 μm to 38. Mu.m.

[ method of manufacturing semiconductor device ]

The tape for semiconductor processing of the present application is preferably used for manufacturing semiconductor chips, which are obtained by singulating (dividing) a semiconductor wafer into chips by back grinding of the semiconductor wafer, the semiconductor wafer being a semiconductor wafer (hereinafter referred to as "semiconductor wafer a") in which a modified layer is formed inside the semiconductor wafer by laser light irradiation along a singulation target area of each chip, or a semiconductor wafer (hereinafter referred to as "semiconductor wafer B") in which a groove is formed by mechanical means along a singulation target area of each chip.

Here, the "back surface of the semiconductor wafer" means a surface of the semiconductor wafer opposite to a pattern surface on which a circuit or the like of the semiconductor element is formed. Specifically, the pattern surface refers to a modified layer formation surface in the semiconductor wafer a and a groove formation surface in the semiconductor wafer B.

The "singulated predetermined area of each chip" refers to a scribe line of the wafer.

The term "singulated chips" refers to a state in which semiconductor chips are singulated from a semiconductor wafer, and includes a state in which singulated semiconductor chips are bonded to the tape for semiconductor processing of the present application.

The semiconductor wafer a is a semiconductor wafer in which a modification layer is formed inside the semiconductor wafer by irradiating laser light along a predetermined region for singulation of each chip. The thickness T is formed in advance on the semiconductor wafer 5 by laser irradiation _A By the above method, the thickness T is adjusted to the thickness T of the semiconductor wafer 5 during the back grinding process of the semiconductor wafer _A The same or thinner than the thickness T _A By grinding, the semiconductor wafer 5 can be thinned and the semiconductor chips can be singulated at the same time. Thickness T _A The thickness of the semiconductor wafer before back grinding is not particularly limited as long as it is smaller than that of the wafer, but is actually about 20 μm to 30 μm larger than the final thickness of the wafer.

This method is a method of combining the invisible dicing and the dicing first, and is also called a chip singulation method for coping with a narrow scribe line width. According to this aspect, since the modified layer of silicon (semiconductor wafer) is cleaved by stress and singulated during wafer back surface grinding, the kerf width is zero, the chip yield is high, and the flexural strength is also improved.

The semiconductor wafer B is a semiconductor wafer with grooves formed by mechanical means along the singulation scheduled area of each chipA conductor wafer. The thickness T is preformed in the semiconductor wafer 5 by mechanical means (e.g. dicing blade) _B Thereby, the thickness T is adjusted to the thickness T of the semiconductor wafer 5 during the back grinding process of the semiconductor wafer _B The same or thinner than the thickness T _B By grinding, the semiconductor wafer 5 can be thinned and the semiconductor chips can be singulated at the same time. Thickness T _B The thickness of the semiconductor wafer before back grinding is not particularly limited as long as it is smaller than that of the wafer, but is actually about 20 μm to 30 μm larger than the final thickness of the wafer.

This mode is called DBG (cut-before-first) mode. According to this aspect, the chip spacing, i.e., the width of the kerf (also referred to as scribe line or scribe line) is limited to be narrowed, but the chip bending strength is improved, and breakage of the chip can be suppressed.

A method for manufacturing the semiconductor chip (a method for processing a semiconductor wafer) using the adhesive tape for semiconductor processing of the present application will be described with reference to fig. 2.

In the case where the release film 4 is provided on the adhesive layer 3, the adhesive layer 3 is exposed by peeling the release film 4, and the adhesive tape 1 for semiconductor processing of the present application is laminated using the base material 2 and the adhesive layer 3 (see fig. 2 (a)). The semiconductor processing tape 1 of the present application is bonded to the semiconductor wafer 5 so that the convex portion 51 of the semiconductor wafer 5 contacts the adhesive layer 3, and the semiconductor wafer 5 in which the convex portion 51 is covered with the semiconductor processing tape 1 of the present application is obtained (see fig. 2 (b)). Here, the convex portion 51 is a portion that can constitute a semiconductor chip when singulated in a semiconductor wafer, and generally has a pattern surface on which a circuit or the like of a semiconductor element is formed.

The back surface of the semiconductor wafer 5 is ground by the grinder 7, whereby the semiconductor wafer 5 is thinned (see fig. 2 (c)), and finally singulated into semiconductor chips having a patterned surface.

The singulated semiconductor chips are picked up from the tape 1 for semiconductor processing of the present application by a conventional method such as peeling with a peeling tape in a state of being adsorbed on a work tray. In this case, when the adhesive layer 3 is of the ultraviolet curing type, the adhesive force of the adhesive layer 3 is reduced by irradiation of ultraviolet rays, whereby the adhesive layer 3 can be easily peeled from the singulated semiconductor chips.

Examples

Hereinafter, the present application will be described in more detail with reference to examples, but the present application is not limited to these examples.

The densities of the resins used below were measured according to JIS K7112, and the MFR of the resins was measured according to JIS K7210 at 190℃under a load of 21.18N.

Example 1 ]

1. Preparation of adhesive composition

A (meth) acrylic copolymer having an ultraviolet polymerizable carbon-carbon double bond and 3 parts by mass of 2-isocyanatoethyl methacrylate having an isocyanate group reactive with a hydroxyl group in a molecule was reacted with 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 to obtain a (meth) acrylic copolymer having an ultraviolet polymerizable carbon-carbon double bond. To 100 parts by mass of the copolymer, 0.9 parts by mass of an isocyanate compound (trade name: coronate L manufactured by Japanese polyurethane Co., ltd.) and 5.0 parts by mass of a photopolymerization initiator (trade name: irgacure 184 manufactured by BASF Co., ltd.) were mixed as a crosslinking agent to obtain an ultraviolet-curable adhesive composition.

2. Production of a substrate

A substrate was obtained which was produced by extrusion and which was laminated with LLDPE (linear low density polyethylene, metallocene catalyst polymer) 25 μm, COP (cyclic olefin polymer) 50 μm and LLDPE25 μm in this order, and had a total thickness of 100. Mu.m. Here, the ethylene content of the COP was 30% by mass and the MFR was 0.8g/10min. In addition, LLDPE has an MFR of 2.5g/10min and a density of 0.925g/cm ³ 。

3. Manufacture of adhesive tape for semiconductor processing

The adhesive composition was applied to a thickness of 30 μm after dryingThe film was dried on a mold-treated PET film (thickness 25 μm) to evaporate ethyl acetate as a solvent, and then the film was bonded to a base material to transfer an adhesive to the base material side, thereby obtaining a semiconductor processing tape of example 1. As shown in fig. 1, the semiconductor processing tape 1 has a structure in which a base film 2, an adhesive layer 3, and a release film 4 are laminated in this order. The base film 2 has a layer B laminated in this order from the pressure-sensitive adhesive layer 3 side ₁ Layer A, layer B ₂ Is a structure of (a).

Example 2 ]

The same procedure as in example 1 was repeated except that LLDPE was changed to LLDPE (metallocene catalyst polymer) having an MFR of 4g/10min to obtain a tape for semiconductor processing of example 2.

Example 3 ]

The semiconductor processing tape of example 3 was obtained in the same manner as in example 2, except that the thickness of the base material was changed to LLDPE35 μm, COP80 μm, and total thickness of LLDPE35 μm was 150. Mu.m.

Example 4 ]

Except that LLDPE was changed to have an MFR of 7.0g/10min and a density of 0.964g/cm ³ The semiconductor processing tape of example 4 was obtained in the same manner as in example 1 except that the COP was changed to a COP having an ethylene content of 35 mass% and an MFR of 2.0g/10 min.

Example 5]

Except that LLDPE was changed to have an MFR of 2.0g/10min and a density of 0.918g/cm ³ Except for LLDPE (metallocene catalyst polymer), the adhesive tape for semiconductor processing of example 5 was obtained in the same manner as in example 1.

Example 6]

Except that LLDPE was changed to have an MFR of 4.0g/10min and a density of 0.944g/cm ³ The semiconductor processing tape of example 6 was obtained in the same manner as in example 1 except that the thickness of the base material was changed to 16 μm, COP48 μm and total thickness of the LLDPE16 μm was 80 μm.

Comparative example 1 ]

Except that LLDPE was changed to have an MFR of 3.1g/10min and a density of 0.925g/cm ³ The semiconductor processing tape of comparative example 1 was obtained in the same manner as in example 1 except for the LDPE.

Comparative example 2 ]

A semiconductor processing tape of 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 mass% and an MFR of 2.0g/10 min.

Comparative example 3 ]

Except that LLDPE was changed to have an MFR of 2.5g/10min and a density of 0.928g/cm ³ The semiconductor processing tape of comparative example 3 was obtained in the same manner as in comparative example 1, except that the ethylene-vinyl acetate copolymer was used.

The obtained tape for semiconductor processing was evaluated as follows.

[1 interlayer adhesion ]

Using constituent layers B ₁ And layer B ₂ Films of 1300mm in length, 25mm in width and 100 μm in thickness were produced separately from the resin constituting layer A. The two films thus produced were overlapped in a 25mm×10mm region and thermally bonded at 220 ℃ for 5 seconds to form a bonded portion. The peel strength at a peeling angle of 180℃at a peeling speed of 300mm/min was measured by using a Stretograph (manufactured by Toyo Seisakusho Co., ltd.). The peel strength was evaluated as good when 5N or more and as x when less than 5N.

[2. Heat resistance ]

The adhesive layer side of each tape of the semiconductor processing tapes of examples and comparative examples was bonded to a smooth-surfaced 8-inch dummy wafer (dummy wafer), and the wafer was ground to a thickness of 50 μm using a grinder DGP8760 (trade name) manufactured by di-cisco corporation. After grinding, the belt side was brought into contact with a hot plate, and the belt was heated to 70 ℃ by the hot plate, and the belt was evaluated as "good" when the appearance was unchanged, and as "x" when the appearance was unchanged.

[3 peelability ]

For the 8-inch dummy wafer, the semiconductor processing tape (hereinafter referred to as tape) prepared as described above was attached, and the wafer was ground to a thickness of 50 μm using a grinder DGP8760 (trade name) manufactured by di-cisco corporation. After grinding, the cumulative radiation amount was 500mJ by irradiation from the tape side using a high-pressure mercury lamp/cm ² After the adhesive layer was cured to lower the adhesive strength, the adhesive tape was adhered to the work tray with the adhesive tape facing upward, and the adhesive tape was peeled off using a peeling tape (manufactured by the eastern electrician company). The evaluation was "good" when the interface between the wafer and the adhesive layer was peeled off, and "X" when the interface was not peeled off or the other portions were peeled off.

[4. Cracking ]

For an 8-inch dummy wafer (thickness 725 μm) having a chip size of 10mm by 12mm and a groove having a depth of 75 μm formed along a predetermined region for singulation, the semiconductor processing tape (hereinafter referred to as tape) prepared as described above was attached to the side on which the groove was formed, and the wafer was ground to a thickness of 50 μm using a grinder DGP8760 (trade name) manufactured by the company di-cisco, and the chip was singulated. After grinding, the tape side was irradiated with a high-pressure mercury lamp to a cumulative radiation of 500mJ/cm ² After the adhesive layer was cured to lower the adhesive strength, each chip was peeled off from the tape, and cracks at the chip ends were observed by a microscope. The number of chips having cracks was evaluated as "good" when 10 or less and as "delta" when 10 to 20 and as "x" when 20 or more were produced.

[ Table 1 ]

From table 1, examples 1 to 6, which are tapes for semiconductor processing specified in the present application, show good results in heat resistance, peelability, interlayer adhesion, and suppression of crack generation. In contrast, the tapes for semiconductor processing of comparative examples 1 and 2 were poor in peelability and interlayer adhesion, and the tapes for semiconductor processing of comparative example 3 were poor in interlayer adhesion.

The present application has been described in connection with the embodiments thereof, but the inventors believe that unless specifically specified, the application is not limited to any details of the description, and should be construed broadly without departing from the spirit and scope of the application as set forth in the appended claims.

The present application claims priority from japanese patent application 2017-046435, which was filed in japan on 3-10 of 2017, which is hereby incorporated by reference and made a part of the description of the present specification.

Symbol description

1. Adhesive tape for semiconductor processing

2. Substrate material

3. Adhesive layer

4. Release film

5. Semiconductor wafer

7. Grinding machine

51. Convex part

Claims

1. A tape for semiconductor processing comprising a base material and an adhesive layer provided on one side of the base material, wherein the base material is composed of a multilayer structure, at least 1 layer of the multilayer structure is a layer A containing 80 mass% or more of a cyclic olefin polymer, a layer B containing a linear low-density polyethylene or a high-density polyethylene is provided in addition to the layer A,

the multilayer structure is composed of 3 or more layers formed by sequentially laminating layers B/A/B, and layers B, A and B are sequentially laminated from the side of the adhesive layer.

2. The semiconductor processing tape according to claim 1, wherein the linear low density polyethylene has a density of 0.95g/cm ³ The following is given.

3. The adhesive tape for semiconductor processing according to claim 1 or 2, wherein the linear low density polyethylene has a melt flow rate of 4.0g/10min or less.

4. The semiconductor processing tape according to claim 1 or 2, wherein the linear low density polyethylene is a metallocene polyethylene.

5. The tape for semiconductor processing according to claim 1 or 2, which is used for manufacturing semiconductor chips, wherein the semiconductor chips are singulated into chips by back grinding of a semiconductor wafer, the semiconductor wafer being a semiconductor wafer having a modified layer formed inside the semiconductor wafer by irradiating laser light along a singulation scheduled area of each chip or a semiconductor wafer having grooves formed by mechanical means along a singulation scheduled area of each chip.