TWI705119B - Adhesive tape for semiconductor processing - Google Patents

Abstract

The present invention is an adhesive tape for semiconductor processing, which is an adhesive tape composed of a substrate and an adhesive layer disposed on a single side of the substrate, and is characterized in that the substrate is composed of a multilayer structure, and the multilayer At least one layer of the structure is layer A containing more than 80% by mass of cyclic olefin polymer. In addition to layer A, there is layer B containing linear low-density polyethylene or high-density polyethylene.

Description

Adhesive tape for semiconductor processing

The present invention relates to an adhesive tape for semiconductor processing, in detail, it relates to an adhesive tape for semiconductor processing in semiconductor wafer processing, and in more detail, it relates to an adhesive tape suitable for back grinding of semiconductor wafers. Surface protective adhesive tape for semiconductor processing in the manufacturing method of semiconductor wafers transformed into wafers.

In the processing step of a semiconductor wafer (hereinafter also referred to as a wafer), after patterning on the surface of the wafer, so-called back grinding and polishing are performed to grind and grind the back of the wafer to a specific thickness. At this time, in order to protect the surface of the wafer, a surface protection adhesive tape is attached to the surface of the wafer, and the back of the wafer is ground in this state. As a surface protection adhesive tape, it is disclosed that a plastic film such as polyolefin is provided with an adhesive layer mainly composed of an acrylic polymer (for example, refer to Patent Document 1).

On the other hand, with the popularization of IC cards, the rapid expansion of semiconductor memory represented by USB memory, and the popularization of small devices such as smart phones or input boards, the industry seeks further thinner chips. For example, compared to wafers with a thickness of about 200 to 350 μm in the past, it is required to be thinned to a thickness of 50 to 100 μm or less.

Generally, the wafer on which the circuit pattern is formed is thinned by the back grinding step. The thin film wafer after grinding is prone to wafer warping (hereinafter referred to as warpage) due to the difference in shrinkage between silicon, circuit, protective layer, and shrinkage of the adhesive tape. The thinner the wafer is, the less the rigidity of the wafer itself is, so there may be a problem of warping that makes the wafer transport or processing in the device impossible.

In addition, if the final thickness of the wafer after back grinding becomes 100 µm or less, the strength of the wafer will decrease, cracks may occur due to slight impact or defects, and the yield may decrease. In addition, even if there is no crack in the back grinding, in the subsequent wafer singulation (hereinafter referred to as dicing) step, mechanical cutting is performed with a diamond blade, so there are defects due to the self-cutting line (hereinafter referred to as fragments) ) A condition that causes the chip to crack.

Regarding the processing of thin film wafers as described above, for example, Patent Document 2 proposes a method for dividing a wafer, which is formed by dicing from the wafer circuit side at a predetermined position (a predetermined position for dividing the wafer) before back grinding. After the groove is larger than the final predetermined wafer thickness and smaller than the original wafer thickness, the thin film is thinned to the depth of the groove by back grinding, and the back grinding and wafering are performed at the same time.

In addition, as a method similar to the above, for example, Patent Document 3 also discloses a laser processing method, which is to perform laser irradiation at a predetermined position of the wafer to be divided, instead of grooves, to form a modified layer inside the wafer, and back grinding At this time, the modified layer is used as a starting point for division and wafer formation. If this method is used, since there is no groove as in the past, the distance between the chips can be approximately zero, and more chips can be obtained from one wafer. In addition, there is no impact generated by the cutting of the diamond blade, so debris can be eliminated.

[Prior Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Application Publication No. 2001-240842

[Patent Document 2] JP 11-40520 A

[Patent Document 3] JP 2002-192370 A

On the other hand, the method disclosed in Patent Document 3 above uses a laser to form the modified layer, so the distance between the wafers is approximately zero. If the wafer is shifted due to external factors such as deformation of the surface protection tape or shear force during back grinding, The problem is that it is easy to contact with adjacent chips and cracks easily occur from this part.

In addition, the inventors of the present invention have conducted intensive research, and as a result, it has been found that when a substrate composed of a multilayer structure with a specific layer is used as the substrate of the tape, the adhesion between the layers constituting the multilayer structure is important. If the adhesiveness is not sufficient, the peelability will be reduced, or delamination will occur during the processing of the semiconductor wafer as the adherend, resulting in wafer breakage.

Therefore, the present invention solves the above-mentioned problems, and its problem is to provide an adhesive tape for semiconductor processing, which is used in the processing of semiconductor wafers, especially in the back grinding step of silicon wafers, etc., even if it is ground into a thin film, it has excellent peelability. In addition, the interlayer adhesion is excellent, and the occurrence of defective wafers can be sufficiently suppressed.

The above-mentioned problems of the present invention are solved by the following means.

(1)

An adhesive tape for semiconductor processing, which is an adhesive tape composed of a substrate and an adhesive layer provided on a single side of the substrate, characterized in that the substrate is composed of a multilayer structure, and at least one layer of the multilayer structure It is a layer A containing 80% by mass or more of a cyclic olefin polymer. In addition to this layer A, there is a layer B containing linear low-density polyethylene or high-density polyethylene.

(2)

Such as (1) the adhesive tape for semiconductor processing, wherein the linear low-density polyethylene has a density of 0.95 g/cm ³ or less.

(3)

Such as (1) or (2) of the adhesive tape for semiconductor processing, wherein the melt flow rate of the linear low-density polyethylene is 4.0 g/10 min or less.

(4)

Such as the adhesive tape for semiconductor processing in any one of (1) to (3), wherein the linear low density polyethylene is metallocene polyethylene.

(5)

Such as the adhesive tape for semiconductor processing in any one of (1) to (4), which is used in the manufacture of semiconductor wafers, which are manufactured by grinding the backside of the semiconductor wafer to separate the following semiconductor wafers Into a chip, the semiconductor wafer is formed by irradiating a laser along the predetermined area of each wafer with a modified layer inside the semiconductor wafer, or along the predetermined area of each chip by A semiconductor wafer with grooves formed by mechanical means.

The adhesive tape for semiconductor processing of the present invention is excellent in peelability even if it is ground into a thin film during the processing of semiconductor wafers, especially in the back grinding step of silicon wafers, and also has excellent interlayer adhesion, which can sufficiently suppress defective wafers The production.

In addition, the adhesive tape for semiconductor processing of the present invention is used in a method of manufacturing a semiconductor chip that uses the backside grinding of the semiconductor wafer to separate the chip into a thin film, and has excellent peelability and interlayer adhesion. Excellent performance, and can fully suppress the generation of defective chips.

The above and other features and advantages of the present invention should be more clarified based on the following description with appropriate reference to the accompanying drawings.

1‧‧‧Adhesive tape for semiconductor processing

2‧‧‧Substrate

3‧‧‧Adhesive layer

4‧‧‧Peeling film

5‧‧‧Semiconductor Wafer

7‧‧‧Grinding machine

51‧‧‧Protrusion

Fig. 1 is a schematic cross-sectional view schematically showing one form of the 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 adhesive tape for semiconductor processing of the present invention. Figure 2(a) shows the step of peeling the release film from the adhesive tape for semiconductor processing to expose the adhesive layer. Figure 2(b) shows the state where the adhesive tape for semiconductor processing is attached to the convex side of the semiconductor wafer. Figure 2(c) shows the step of grinding the backside of the semiconductor wafer.

[Adhesive tape for semiconductor processing]

The adhesive tape for semiconductor processing of the present invention is an adhesive tape composed of a substrate and an adhesive layer provided on a single side of the substrate, and the substrate has a multilayer structure, and at least one layer of the multilayer structure contains 80 A layer A of a cyclic olefin polymer with a mass% or more, in addition to the layer A, has a layer B containing linear low-density polyethylene or high-density polyethylene.

Hereinafter, a preferred form of the adhesive tape for semiconductor processing of the present invention will be described.

As shown in FIG. 1, the adhesive tape 1 for semiconductor processing of the present invention is a tape obtained by laminating an adhesive layer 3 on a substrate 2 and integrating the two layers. In addition, the adhesive tape 1 for semiconductor processing may be further provided with 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 invention may be in a form in which a laminate of the base material 2, the adhesive layer 3, and the release film 4 is rolled into a roll.

(Substrate 2)

The substrate 2 of the adhesive tape 1 for semiconductor processing of the present invention is composed of a multilayer structure. At least one layer of the multilayer structure is layer A containing a cyclic olefin polymer (hereinafter referred to as "COP"). In addition to this layer A, as at least one layer of the multilayer structure, it has a layer containing linear low-density polyethylene Or layer B of high density polyethylene.

In this specification, COP refers to the ring-opening polymer of cyclic olefin or its hydrogen addition product, and the addition polymer of cyclic olefin, and also includes what is called cyclic olefin copolymer (hereinafter referred to as "COC" ) The addition copolymer of cyclic olefin and chain olefin.

Cyclic olefins as monomers are cyclic olefins or alkynes, and are polymerized by ring opening or addition polymerization What is needed is a compound that can form a polymer. The carbon number is preferably 4-12. Cyclic olefins may include bicyclic olefins, and may further include monocyclic olefins and/or tricyclic or more polycyclic olefins. Examples of monocyclic olefins include cyclic cycloolefins having 4 to 12 carbon atoms, such as cyclobutene, cyclopentene, cycloheptene, and cyclooctene. Examples of bicyclic olefins or polycyclic olefins with three or more rings include: dicyclopentadiene; 2,3-dihydrodicyclopentadiene, methylene octahydrogen, dimethylene octahydrogen Derivatives such as naphthalene, dimethylcyclopentadiene naphthalene and methylene octahydrocyclopentadiene naphthalene; derivatives with substituents such as 6-ethyl octahydronaphthalene; cyclopentadiene and tetrahydroindene, etc. The adducts of cyclopentadiene, 3~4-mers of cyclopentadiene, norbornene, and tetracyclododecene, etc. Preferred are norbornene and tetracyclododecene.

In addition, the chain olefin may be a chain olefin or alkyne, and may be a compound that can form a polymer by addition polymerization with a cyclic olefin. The carbon number is preferably 2-10, more preferably 2-8, and still more preferably 2-4. Specifically, ethylene, propylene, 1-butene, isobutene, 1-pentene, 3-methyl-1-pentene, 4-methyl-1-pentene, 1-hexene, 1- Chain olefins with 2 to 10 carbon atoms such as octene. These chain olefins can be used alone or in combination of two or more, and ethylene is particularly preferred.

In the aforementioned layer A, the content of COP is 80% by mass or more, preferably 90% by mass or more. The upper limit is not particularly limited, but is 100% by mass or less. Furthermore, when COP is COC, the content of COP is the content of COC.

Specific examples of the above COP include "ZEONOR" manufactured by Zeon Corporation, "Topas" manufactured by Polyplastics, etc., both of which are product names.

In COP, the homopolymer of cyclic olefin is an amorphous resin, which is hard and fragile, and must be processed at high temperature when it is formed into a sheet or film.

On the other hand, COC is a copolymer of cyclic olefin and ethylene, so it has flexibility and ductility. In addition, by adjusting the polymerization ratio (content ratio), COC with various characteristics can be obtained.

Among the constituent components of COC, the content of the ethylene component is preferably 30-40% by mass, more preferably 35-40% by mass. If the content of the ethylene component is too small, the substrate may be very brittle, and the adhesive tape for semiconductor processing may break.

Regarding the aforementioned base material 2, as a layer other than layer A containing COP, it has good adhesion to layer A and contains linear low-density polyethylene (hereinafter referred to as "LLDPE") or high-density polyethylene (hereinafter , Called "HDPE") layer B. Furthermore, low-density polyethylene (hereinafter referred to as "LDPE") is not good in terms of being unable to obtain sufficient interlayer adhesion with layer A. If the interlayer adhesion is insufficient, the peelability will be insufficient, and interlayer delamination may occur during the processing of the semiconductor wafer as the adherend, and the wafer may be damaged.

LLDPE and HDPE can be copolymers of ethylene and α-olefin. The α-olefin preferably has a carbon number in the range of 3-10, and examples include propylene, butene-1, pentene-1, hexene-1, 4-methylpentene-1, heptene- 1. Octene-1 and so on.

When LLDPE and HDPE are copolymers of ethylene and α-olefin, the content of the ethylene component in all the constituent components of the copolymer is preferably 95-99% by mass, more preferably 96-98% by mass.

In the aforementioned layer B, the content of LLDPE and HDPE is preferably 50% by mass or more, more preferably 80% by mass or more. The upper limit is not particularly limited, but is 100% by mass or less. Furthermore, when LLDPE and HDPE are copolymers of ethylene and α-olefin, the content of LLDPE and HDPE is the content of the copolymer of ethylene and α-olefin.

The density of LLDPE is preferably 0.95 g/cm ³ or less, more preferably 0.94 g/cm ³ or less, and still more preferably 0.93 g/cm ³ or less. The lower limit is actually 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 still more preferably 1.0 g/10 min or less. The lower limit is actually 0.5g/10min or more.

In addition, the density of HDPE is preferably 0.97 g/cm ³ or less, more preferably 0.96 g/cm ³ or less. The lower limit is actually 0.5 g/cm ³ or more.

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

MFR is a value at a temperature of 190°C and a load of 21.18N. 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 COC-containing layer A.

In this specification, "metallocene polyethylene" refers to an ethylene-based polyolefin obtained by using a metallocene catalyst (hereinafter, sometimes referred to as "metallocene-catalyst ethylene-based polyolefin"), which can be obtained by using ethylene, or A mixed monomer of ethylene and α-olefin is obtained by polymerizing in the presence of a metallocene catalyst. Therefore, the ethylene-based polyolefin obtained by using the metallocene catalyst includes polyethylene obtained by the polymerization reaction in the presence of the metallocene catalyst, and a copolymer of ethylene and α-olefin.

The metallocene catalyst is a transition metal component composed of a metallocene, that is, two substituted or unsubstituted cyclopentadienyl rings and a complex composed of various transition metals, and an organoaluminum component, especially The general term for the catalyst composed of 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, in general, the following formula (Cp) ₂ MR ₂

(In the formula, 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, those obtained by reacting an organoaluminum compound with water are linear aluminoxane and cyclic aluminoxane. These aluminoxanes can be used alone or in combination with other organic aluminum.

The polymerization method of ethylene or ethylene and α-olefin using a metallocene catalyst is well-known in most publications. In the presence of the above-mentioned metallocene catalyst, the method can be carried out in an organic solvent, a liquid monomer, or a gas phase method. It is synthesized by polymerization, but those obtained by any of the known methods can also be used for the purpose of the present invention.

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

The metallocene catalyst 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) used as an indicator of molecular weight distribution is preferably 4.0 or less, more preferably It is 3.5 or less, more preferably 3.2 or less. Furthermore, in order to improve the formability, it is preferable to use a branch having a longer chain introduced during or after the polymerization. In addition, the metallocene catalyst ethylene 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/10 min, preferably 0.3 to 5 g/10 About minutes.

The presence of the metallocene catalyst ethylene polyolefin in layer B can be confirmed by the following method. That is, the layer B is cut to a thickness of 100μm using glass as a sample, and it is laid on a scanning electron microscope SEM, and the generated fluorescent X-rays are measured with an energy distribution analyzer to confirm that there is equivalent to Zr (zirconium) or Hf (Hf) the peak of energy.

The metallocene catalyst ethylene-based polyolefin can use synthetic products, but can also be selected from commercially available products. As commercially available products, Umerit (registered trademark) manufactured by Ube Maruzen Polyethylene Co., Ltd., EXCELLEN (registered trademark) manufactured by Sumitomo Chemical Co., Ltd., Harmorex (registered trademark) and KERNEL (registered trademark) manufactured by Japan Polyethylene Co., Ltd. )Wait.

Since the aforementioned LLDPE and HDPE are soft, they have good cushioning properties during wafer grinding. Also, 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 base material 2, or may be used in combination with resins and blended. In addition, in addition to the above-mentioned resins, the layer constituting the base material 2 may contain additives such as colorants, antioxidants, and antistatic agents as needed within a range that does not affect physical properties.

Although the thickness of the aforementioned substrate 2 is not particularly limited, it is preferably 50 to 200 μm, more preferably 80 to 180 μm.

In terms of rigidity, the thickness of the layer A is preferably 20 to 100 μm, more preferably 30 to 60 μm. In addition, the thickness of the layer B is preferably 10 to 100 μm, more preferably 20 to 80 μm in terms of flexibility.

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

The layer structure of the base material 2 is not particularly limited as long as it is a multilayer structure including at least one layer of layer A and layer B, but it is preferably a layer structure in which layer A and layer B are laminated adjacently, and more preferably sequentially in a layer B ₁ / layer A / layer B of the above three layers constitute the laminate layer _2, and further preferably successively in a layer B ₁ / layer A / layer B ₂ laminate composed of 3 layers. Here, the layer B ₁ and the layer B ₂ refer to the above-mentioned layer B, and may be the same layer or different layers.

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

The manufacturing method of the said base material 2 is not specifically limited. It can be produced by extrusion, expansion, casting and other information. Moreover, it is also possible to use an adhesive agent etc. to bond the film formed independently to another film to make the base material 2.

(Adhesive layer 3)

The adhesive layer 3 of the adhesive tape 1 for semiconductor processing of the present invention may be a layer containing an adhesive, for example, it is formed using an adhesive composition. The adhesive composition is not particularly limited, and can include: common compositions containing acrylic, rubber, silicone and other adhesives. In terms of weather resistance, price, etc., an acrylic adhesive is suitably used.

Examples of the acrylic adhesive include copolymers having (meth)acrylate as a constituent component (hereinafter, referred to as "(meth)acrylate copolymer"). In addition to the (meth)acrylate copolymer, the curing agent described later may be contained.

Furthermore, in the present invention, the (meth)acrylic monomer includes both of the acrylic monomer and the methacrylic monomer.

Examples of (meth)acrylates as constituent components of the above-mentioned (meth)acrylate copolymers include: methyl, ethyl, n-propyl, isopropyl, n-butyl, tertiary butyl, isopropyl Butyl, pentyl, isopentyl, hexyl, heptyl, cyclohexyl, 2-ethylhexyl, octyl, isooctyl, nonyl, isononyl, decyl, isodecyl, undecyl, Lauryl, tridecyl, tetradecyl, stearyl, octadecyl, dodecyl and other straight-chain or branched alkyl groups with carbon number 30 or less, preferably carbon number 4-18 Alkyl acrylate or alkyl methacrylate. These alkyl (meth)acrylates may be used alone, or two or more kinds may be used in combination.

In the constituent components of the (meth)acrylic copolymer, the content of the (meth)acrylate component is preferably 80% by mass or more, more preferably 90% by mass or more, and still more preferably 95 to 99.9% by mass.

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

啉、乙酸乙烯酯、苯乙烯、丙烯腈等。該等構成成分可單獨使用，亦可將2種以上併用。 Examples of other constituent components include (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, and fumaric acid. , And carboxyl-containing monomers such as crotonic acid, anhydride monomers such as maleic anhydride or itaconic anhydride, hydroxyalkyl (meth)acrylates (preferably the above-mentioned alkyl (meth)acrylates are substituted by hydroxy ) And other hydroxyl-containing monomers, styrene sulfonic acid, allyl sulfonic acid, 2-(meth)acrylamide-2-methylpropanesulfonic acid, (meth)acrylamide propanesulfonic acid, (form Sulfonic acid group-containing monomers such as sulfopropyl acrylate and (meth)acryloyloxynaphthalenesulfonic acid, phosphoric acid group-containing monomers such as 2-hydroxyethyl acryloyl phosphate, (meth)acrylamide, N-methylolamide (meth)acrylate, alkylaminoalkyl (meth)acrylate (e.g. dimethylaminoethyl methacrylate, tert-butylaminoethyl methacrylate, etc.), N-vinylpyrrolidone, acrylic acid

Phosphine, vinyl acetate, styrene, acrylonitrile, etc. These constituent components may be used alone or in combination of two or more kinds.

In the solid content of the adhesive layer 3, the content of the (meth)acrylic copolymer (converted to the content in the state before the reaction with the curing agent or photopolymerizable compound described later) is preferably 80% by mass or more, more preferably 90% by mass or more, more preferably 95 to 99.9% by mass.

As the curing agent, the curing agent disclosed in JP 2007-146104 A can be used. Examples include: 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, 1,3-bis(N,N-diglycidylaminomethyl)toluene, 1, 3-bis(N,N-diglycidylaminomethyl)benzene, N,N,N,N'-tetraglycidyl metaxylylenediamine and other epoxy resins with more than 2 epoxy groups in the molecule Compound, 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylene diisocyanate, diphenylmethane-4,4'-diisocyanate Isocyanate compounds with more than two isocyanate groups in the molecule, tetramethylol tri-β-aziridinyl propionate, trimethylol tri-β-aziridinyl propionate, trimethylol Propane tri β-aziridinyl propionate, trimethylolpropane tri β-(2-methylaziridine) propionate and other aziridine compounds with more than two aziridin groups in the molecule, etc. . The content of the hardener may be adjusted according to the required adhesive force, and it is preferably 0.01-10 parts by mass, more preferably 0.1-5 parts by mass relative to 100 parts by mass of the (meth)acrylate copolymer.

The adhesive layer 3 is also preferably composed of a radiation curable adhesive containing a photopolymerizable compound and a photopolymerization initiator in addition to the aforementioned adhesive. By containing an adhesive, a photopolymerizable compound, and a photopolymerization initiator, it can be cured by irradiating radiation (preferably ultraviolet rays), and the adhesive force of the adhesive layer 3 is reduced. As such a photopolymerizable compound, for example, those disclosed in Japanese Patent Application Laid-Open No. 60-196956 and Japanese Patent Application Publication No. 60-223139 that have at least 2 in a molecule capable of three-dimensional network formation by light irradiation can be used. Low molecular weight compounds with more than one photopolymerizable carbon-carbon double bond or oligomers obtained by polymerization of these.

Specifically, the above-mentioned photopolymerizable compound may be used: trimethylolpropane tri(meth)acrylate, neopenteritol di(meth)acrylate, neopenteritol tri(meth)acrylate, new Pentylene erythritol tetra (meth) acrylate, dineopentaerythritol monohydroxy penta (meth) acrylate, dineopentaerythritol 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 two (Meth)acrylate, epoxy (meth)acrylate ((meth)acrylic adduct of epoxy compound), polyester (meth)acrylate ((meth)acrylic adduct of polyester) ), and amine (meth)acrylate ((meth)acrylic acid adduct of amine ester), etc.

、聯苯醯縮二甲醇、α-羥基環己基苯基酮、2-羥基甲基苯基丙烷等。 As the above-mentioned photopolymerization initiator, the photopolymerization initiator described in JP 2007-146104 A or JP 2004-186429 A can be used. Specifically, isopropyl benzoin ether, isobutyl benzoin ether, benzophenone, Michele ketone, chlorine 9-oxysulfur can be used

, Biphenyl dimethyl acetal, α-hydroxycyclohexyl phenyl ketone, 2-hydroxymethyl phenyl propane, etc.

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

The radiation polymerizable (meth)acrylic copolymer is a copolymer having a reactive group that can undergo polymerization by irradiation with radiation, especially 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 vinyl, allyl, styryl, and (meth)acryloxy groups. , (Meth) acrylamido, etc.

The above-mentioned radiation polymerizable (meth)acrylic copolymer is not particularly limited, and examples thereof include: a (meth)acrylic copolymer having a functional group a, and a functional group b that can react with the functional group a and radiation A (meth)acrylic copolymer obtained by reacting a polymerizable carbon-carbon double bond compound (hereinafter referred to as "radiation polymerizable compound having functional group b").

As the (meth)acrylic copolymer having the aforementioned carbon-carbon double bond, for example, the same materials as those described in paragraph numbers [0036] to [0055] of JP 2014-192204 A can be cited.

Among the radiation polymerizable compounds 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. Examples of radiation polymerizable compounds having a specific functional group b include acrylic acid, methacrylic acid, cinnamic acid, itaconic acid, fumaric acid, phthalic acid, 2-hydroxyalkyl acrylate, methyl 2-hydroxyalkyl acrylates, ethylene glycol monoacrylates, ethylene glycol monomethacrylates, N-methylol methacrylamide, N-methylol methacrylamide, allyl Alcohol, N-alkylaminoethyl acrylate, N-alkylaminoethyl methacrylate, acrylamide, methacrylamide, maleic anhydride, itaconic anhydride, transbutane Alkenic anhydride, phthalic anhydride, glycidyl acrylate, glycidyl methacrylate, allyl glycidyl ether, polyisocyanate compound using monomers having hydroxyl or carboxyl groups and radiation polymerizable carbon-carbon double bonds Part of the isocyanate group is amine esterified.

In the reaction between the (meth)acrylic copolymer having the functional group a and the radiation polymerizable compound having the functional group b, by remaining unreacted functional groups, the acid value, hydroxyl value, etc. can be appropriately set.

The radiation polymerizable (meth)acrylic copolymer can be obtained by solution polymerization in various solvents. As the organic solvent when the solution polymerization is performed, ketone-based, ester-based, alcohol-based, and aromatic-based solvents can be used. It is preferable to use a solvent that is usually a good solvent for acrylic polymers and has a boiling point of 60 to 120°C. For example, toluene, ethyl acetate, isopropanol, benzene, methyl cellophane, ethyl cellophane, acetone, methyl ethyl ketone, etc. can be used. As the polymerization initiator, radical generators such as azo series such as α,α'-azobisisobutyronitrile, and organic peroxide series such as benzyl peroxide can be used. At this time, if necessary, a catalyst and a polymerization inhibitor can be used together, and by adjusting the polymerization temperature and polymerization time, a copolymer with a desired molecular weight can be obtained. In addition, 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 adhesive composition constituting the adhesive layer 3 may contain a release agent, an adhesion imparting agent, an adhesion regulator, a surfactant, etc., or other modifiers, if necessary. It may also contain inorganic compound fillers.

The adhesive layer 3 can be formed by coating the adhesive composition on the release film 4, drying, and transferring to the base material 2. In the present invention, the thickness of the adhesive layer 3 is preferably 10-60 μm, more preferably 20-50 μm. If it is too thick, the adhesive tape 1 for semiconductor processing may be peeled off due to excessive adhesion to the surface of the semiconductor wafer 5 (refer to FIG. 2) and embedding in the convex portion 51 (refer to FIG. 2) on the surface of the semiconductor wafer 5 , There is a risk of paste residue on the surface of the semiconductor wafer 5. By setting it below the above upper limit value, excessive adhesion of the adhesive can be suppressed. If it is too thin, the adhesive layer 3 cannot follow the protrusions 51 on the surface of the semiconductor wafer 5, causing grinding water containing silicon grinding chips to enter the gap between the adhesive tape 1 for semiconductor processing and the semiconductor wafer 5 and contaminate the semiconductor. The so-called seepage of the circuit surface of the wafer 5 is the main cause.

(Release film 4)

The release film 4 is also called a release film, a release layer, or a release liner, and is provided as needed to protect the radiation-curing adhesive layer and to smooth the radiation-curing adhesive layer. Examples of the constituent material of the release film 4 include synthetic resin films such as polyethylene, polypropylene, and polyethylene terephthalate, paper, and the like. In order to improve the peelability of the self-adhesive layer 3, the surface of the peeling film 4 may be subjected to peeling treatments such as polysilicon oxidation treatment, long-chain alkyl treatment, fluorine treatment, etc., if necessary. In addition, if necessary, in order to prevent the reaction of the adhesive layer 3 due to environmental ultraviolet rays, an anti-ultraviolet treatment may be implemented. The thickness of the release film 4 is usually 10-50 μm, preferably 25-38 μm.

[Method of Manufacturing Semiconductor Device]

The adhesive tape for semiconductor processing of the present invention can be preferably used for the manufacture of semiconductor wafers, which are manufactured by singulating (dividing) the following semiconductor wafers into wafers by grinding the backside of the semiconductor wafers. A semiconductor wafer is a semiconductor wafer (hereinafter referred to as "semiconductor wafer A") in which a laser is irradiated along the predetermined area of each wafer to form a modified layer inside the semiconductor wafer, or along the The semiconductor wafer (hereinafter referred to as "semiconductor wafer B") in which grooves are formed in the singulated predetermined region by mechanical means.

Here, "the back surface of the semiconductor wafer" refers to the surface of the semiconductor wafer on the opposite side to the pattern surface on which the circuits etc. of the semiconductor element are formed. Specifically, the pattern surface refers to the surface where the modified layer of the semiconductor wafer A is formed and the surface where the groove of the semiconductor wafer B is formed.

The "predetermined area for singulation of each chip" refers to the scribing of the wafer.

In addition, "singulation into a chip" refers to a state in which a semiconductor wafer is singulated into a semiconductor chip. The singulated semiconductor chip includes a state in which it is attached to the adhesive tape for semiconductor processing of the present invention.

The semiconductor wafer A is a semiconductor wafer in which a modified layer is formed inside the semiconductor wafer by irradiating a laser along the predetermined singulation area of each wafer. By laser irradiation, the semiconductor wafer 5 is formed with a modified layer of a thickness T _A, when the back surface of the semiconductor wafer after the grinding process to thereby, the semiconductor wafer 5 to the thickness T _A is the same or thinner than the aforementioned The thickness T _A is used for grinding, whereby the semiconductor wafer 5 can be thinned and singulated into semiconductor wafers at the same time. The thickness T _A is not particularly limited as long as it is smaller than the thickness of the semiconductor wafer before back grinding, but it is actually about 20-30 μm larger than the final thickness of the wafer.

This method combines invisible dicing and first dicing and then grinding. It is also known as a wafer singulation method for narrow scribe width. According to this method, the modified layer of silicon (semiconductor wafer) is singulated by stress cleavage during the grinding process of the back surface of the wafer. Therefore, the slit width is zero, the wafer yield is higher, and the bending strength is also improved.

The semiconductor wafer B is a semiconductor wafer with grooves formed by mechanical means along the predetermined singulation area of each wafer. By mechanical means (for example, a dicing blade), a groove with a thickness T _B is formed in the semiconductor wafer 5, so that the semiconductor wafer 5 and the above-mentioned thickness T are used for the subsequent grinding of the back surface of the semiconductor wafer. _{B is the} same as or thinner than the above-mentioned thickness T _B by grinding, whereby the semiconductor wafer 5 can be thinned and singulated into semiconductor wafers at the same time. The thickness T _B is not particularly limited as long as it is smaller than the thickness of the semiconductor wafer before back grinding, but it is actually about 20-30 μm larger than the final thickness of the wafer.

This method is called the DBG (Cut and Grind) method. According to this method, the gap between the wafers, that is, the narrowing of the width of the notch (also referred to as a scribe line or a dicing line) is limited, but the bending strength of the wafer is improved, and the damage of the wafer can be suppressed.

2, the method of manufacturing the above-mentioned semiconductor wafer (the processing method of the semiconductor wafer) using the adhesive tape for semiconductor processing of the present invention will be described.

Regarding the adhesive tape 1 for semiconductor processing of the present invention, when there is a release film 4 on the adhesive layer 3, peel off the release film 4 to expose the adhesive layer 3, and use a semiconductor laminated with a substrate 2 and an adhesive layer 3 Adhesive tape 1 for processing (refer to Fig. 2(a)). The adhesive tape 1 for semiconductor processing of the present invention is attached to the semiconductor wafer 5 in such a way that the protrusions 51 of the semiconductor wafer 5 are in contact with the adhesive layer 3, so that the protrusions 51 are covered by the adhesive tape 1 for semiconductor processing of the present invention The semiconductor wafer 5 (refer to Figure 2(b)). Here, the convex portion 51 refers to a portion of a semiconductor wafer that can constitute a semiconductor wafer when it is singulated, and usually has a patterned surface on which a circuit of a semiconductor element is formed.

The back surface of the semiconductor wafer 5 is ground by the grinder 7, thereby thinning the semiconductor wafer 5 (see FIG. 2(c)), and finally singulated into a semiconductor wafer with a patterned surface.

The singulated semiconductor chip is picked up from the adhesive tape 1 for semiconductor processing of the present invention by a conventional method such as peeling with a peeling tape while being adsorbed on the work plate. At this time, when the adhesive layer 3 is an ultraviolet curable type, the adhesive force of the adhesive layer 3 is reduced by ultraviolet irradiation, so that the adhesive layer 3 can be easily peeled off from the singulated semiconductor wafer.

[Example]

Hereinafter, the present invention will be further described in detail based on examples, but the present invention is not limited to these.

Furthermore, the density of the resin used below is the value measured at a temperature of 190°C and a load of 21.18N according to JIS K7112, and the MFR of the resin is a value measured at a temperature of 190°C and a load of 21.18N according to JIS K7210.

<Example 1>

1. Preparation of adhesive composition

3 parts by mass of 2-isocyanatoethyl methacrylate having an ultraviolet-polymerizable carbon-carbon double bond and an isocyanate group reacting with a hydroxyl group in the molecule and 2-ethylhexyl acrylate as an acrylate monomer 80 Parts by mass, 20 parts by mass of 2-hydroxyethyl acrylate as an acrylate monomer with functional groups, and 1 part by mass of methyl methacrylate as constituent components are reacted to obtain UV-polymerizable (Meth) acrylic copolymer with carbon-carbon double bond. With respect to 100 parts by mass of the copolymer, 0.9 parts by mass of an isocyanate compound (manufactured by Nippon Polyurethane Industry Co., Ltd., brand name: Corona L) and a photopolymerization initiator (manufactured by BASF Company, brand name: Irgacure 184) were mixed as a crosslinking agent. ) 5.0 parts by mass to obtain an ultraviolet curable adhesive composition.

2. Production of substrate

The following base material was obtained: by the extrusion method, the total thickness of LLDPE (linear low-density polyethylene, metallocene catalyst polymer) 25μm, COP (cyclic olefin polymer) 50μm, and LLDPE25μm were sequentially laminated to 100μm. The substrate. Here, the ethylene content of the COP is 30% by mass, and the MFR is 0.8 g/10 min. In addition, the MFR of LLDPE is 2.5g/10min, and the density is 0.925g/cm ³ .

3. Production of adhesive tape for semiconductor processing

On a PET film (thickness 25μm) that has undergone a mold release treatment, the adhesive composition is applied so that the thickness after drying becomes 30μm, dried to evaporate ethyl acetate as the solvent, and then bonded to the substrate The adhesive was transferred to the substrate side to obtain the adhesive tape for semiconductor processing of Example 1. As shown in FIG. 1, the adhesive tape 1 for semiconductor processing has a structure in which a base film 2, an adhesive layer 3, and a release film 4 are laminated in this order. In addition, the base film 2 has a structure in which a layer B1, a layer A, and a layer B2 are sequentially laminated from the adhesive layer 3 side.

<Example 2>

The adhesive tape for semiconductor processing of Example 2 was obtained by the same method as Example 1, except that LLDPE was changed to LLDPE (metallocene catalyst polymer) with an MFR of 4 g/10 min.

<Example 3>

The adhesive tape for semiconductor processing of Example 3 was obtained by the same method as Example 2 except that the thickness of the base material was changed to LLDPE 35 μm, COP 80 μm, and LLDPE 35 μm in total thickness of 150 μm.

<Example 4>

Except that the LLDPE was changed to a MFR of 7.0g / 10min, a density of 0.964g / cm HDPE ^3, the COP is changed to an ethylene content of 35 mass%, MFR other than COP 2.0g / 10min, the same as with the embodiment of Example 1 The method obtains the adhesive tape for semiconductor processing of Example 4.

<Example 5>

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

<Example 6>

Except that the LLDPE was changed to a MFR of 4.0g / 10min, a density of 0.944g / cm LLDPE ^3, the sum of the thickness of the substrate is changed LLDPE16μm, COP48μm, LLDPE16μm than the total thickness of 80 m, in the same manner as in Example 1 of the embodiment is obtained Example 6 Adhesive tape for semiconductor processing.

<Comparative Example 1>

The adhesive tape for semiconductor processing of Comparative Example 1 was obtained by the same method as Example 1, except that LLDPE was changed to LDPE with an MFR of 3.1 g/10 min and a density of 0.925 g/cm ³ .

<Comparative Example 2>

Except for changing the COP to a COP with an ethylene content of 35% by mass and an MFR of 2.0 g/10 min, the adhesive tape for semiconductor processing of Comparative Example 2 was obtained in the same manner as in Comparative Example 1.

<Comparative Example 3>

Except that LLDPE was changed to an ethylene vinyl acetate copolymer with an MFR of 2.5 g/10 min and a density of 0.928 g/cm ^3, the adhesive tape for semiconductor processing of Comparative Example 3 was obtained in the same manner as in Comparative Example 1.

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

[1. Interlayer adhesion]

Using the resin constituting the layer B1 and the layer B2 and the resin constituting the layer A, a film having a length of 1300 mm, a width of 25 mm, and a thickness of 100 μm was produced, respectively. The two kinds of films produced were overlapped in an area of 25 mm×10 mm, and thermocompression-bonded at 220°C for 5 seconds to form a joint. Using a Strograph (manufactured by Toyo Seiki Co., Ltd.), the peel strength was measured at a speed of 300 mm/min and a peel angle of 180°. Those with a peel strength of 5N or more were evaluated as "○", and those with less than 5N were evaluated as "×".

[2. Heat resistance]

Stick the adhesive layer side of each tape of the adhesive tape for semiconductor processing of the embodiment and the comparative example on the 8-inch dummy wafer with a smooth surface, using the grinder DGP8760 (trade name) manufactured by DISCO, to grind the wafer to thickness 50μm. After grinding, the tape side was brought into contact with the hot plate, and the hot plate was heated to 70°C. The appearance without change was evaluated as "○", and the one with change was evaluated as "×".

[3. Peelability]

The adhesive tape for semiconductor processing (hereinafter referred to as adhesive tape) produced above was attached to an 8-inch dummy wafer, and the wafer was ground to a thickness of 50 μm using a grinder DGP8760 (trade name) manufactured by DISCO. After grinding, use a high-pressure mercury lamp to irradiate 500mJ/cm ² of ultraviolet rays from the side of the adhesive tape to harden the adhesive layer and reduce the adhesive force, and then adsorb it on the work plate with the adhesive tape facing up. Use The peeling tape (manufactured by Nitto Denko) peels off the adhesive tape. Those who peeled off the interface between the wafer and the adhesive layer were evaluated as "○", and those that could not be peeled off or peeled off at other parts were evaluated as "×".

[4. Cracking]

An 8-inch dummy wafer (thickness 725μm) with a chip size of 10mm long x 12mm wide and a groove with a depth of 75μm is formed along the predetermined area of singulation. The surface where the groove is formed is used for semiconductor processing. For the adhesive tape (hereinafter referred to as the adhesive tape), using a grinder DGP8760 (trade name) manufactured by DISCO, the wafer was ground to a thickness of 50 μm, and the wafer was singulated. After grinding, use a high-pressure mercury lamp to irradiate 500mJ/cm ² of ultraviolet rays from the side of the adhesive tape to harden the adhesive layer and reduce the adhesive force. Then, each chip is peeled off from the adhesive tape and the chip ends are observed with a microscope. If the number of chips with cracks is 10 or less, it is evaluated as "○", if it is 10-20, it is evaluated as "△", and if it is 20 or more, it is evaluated as "×".

According to the above-mentioned Table 1, Examples 1 to 6 of the adhesive tape for semiconductor processing specified in the present invention showed good results in heat resistance, peelability, interlayer adhesion, and suppression of cracks. In contrast, the adhesive tapes for semiconductor processing of Comparative Examples 1 and 2 had poor releasability and interlayer adhesion, and the adhesive tapes of Comparative Example 3 had poor interlayer adhesion.

The present invention will be described together with its implementation mode, but as long as we are not particularly limited, our invention is not limited to any detailed part of the description, and it is considered that it does not violate the spirit of the invention shown in the scope of the attached patent application It should be interpreted broadly in the context of scope.

This application claims priority based on Japanese Patent Application No. 2017-046435 filed in Japan on March 10, 2017, and the content is incorporated herein by reference as a part of the disclosure of this specification.

1‧‧‧Adhesive tape for semiconductor processing

2‧‧‧Substrate

3‧‧‧Adhesive layer

4‧‧‧Peeling film

Claims (5)

An adhesive tape for semiconductor processing, which is an adhesive tape composed of a substrate and an adhesive layer provided on a single side of the substrate, characterized in that: the substrate is composed of a multilayer structure, and the multilayer structure is at least One layer is layer A containing 80% by mass or more of cyclic olefin polymer. In addition to layer A, there is layer B containing linear low-density polyethylene. The layer A and the layer B are laminated adjacent to each other. In B, the content of linear low-density polyethylene is 50% by mass or more, and the above-mentioned linear low-density polyethylene is metallocene polyethylene. The adhesive tape for semiconductor processing according to claim 1, wherein the linear low-density polyethylene has a density of 0.95 g/cm ³ or less. The adhesive tape for semiconductor processing according to claim 1, wherein the melt flow rate of the linear low-density polyethylene is 4.0 g/10 min or less. The adhesive tape for semiconductor processing according to claim 2, wherein the melt flow rate of the linear low-density polyethylene is 4.0 g/10 min or less. The adhesive tape for semiconductor processing according to any one of claims 1 to 4, which is used in the manufacture of semiconductor wafers, which are manufactured by grinding the backside of the semiconductor wafer to separate the following semiconductor wafers Into a chip, the semiconductor wafer is formed by irradiating a laser along the predetermined area of each wafer with a modified layer inside the semiconductor wafer, or along the predetermined area of each chip by A semiconductor wafer with grooves formed by mechanical means.

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