Wafer processing tape and wafer processing method

Abstract

To provide a wafer processing tape that exhibits excellent wafer separation properties during expansion at temperatures at or above the room temperature, and a wafer processing method using the same.SOLUTION: The wafer processing tape includes a substrate layer having a front surface and a back surface, and an adhesive layer laminated on the front surface of the substrate layer. The holding power of the adhesive layer on SUS304 under a 1000 g load at 40°C is from 10 to 130 hours. The storage modulus of the adhesive layer at 25°C is from 1.0×105 to 1.0×106 Pa.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a wafer processing tape and a wafer processing method. [Background technology]

[0002] When a semiconductor wafer (hereinafter also referred to as "wafer") or the like is diced, a dicing tape is attached to the wafer, the wafer is diced, and the dicing tape is expanded. After expansion, the chips obtained by dicing the wafer are picked up (peeled) from the dicing tape.

[0003] One example of a wafer dicing method is stealth dicing, which involves irradiating a wafer with a laser to form a modified layer. In order to improve the ease of separating wafers when using stealth dicing, Patent Document 1 discloses a dicing sheet that specifies the arithmetic mean roughness of the second surface of the substrate under normal conditions and after heating. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2015 / 190230 Summary of the Invention [Problem to be solved by the invention]

[0005] Patent Document 1 explains that by specifying the arithmetic mean roughness after heating of the surface of the substrate on the side having the adhesive layer for attaching the wafer to a dicing sheet, the dicing sheet has excellent laser light transmittance, allowing the laser light to reach the wafer efficiently, and as a result, improving the ease of separating the wafer.

[0006] To improve wafer divisibility, it is important to consider not only the laser light transmittance in the dicing process but also the physical properties for controlling the behavior of the dicing sheet in wafer dividing processes such as the expanding process, etc. However, the dicing sheet described in Patent Document 1 does not describe at all the physical properties for controlling the behavior of the dicing sheet in the wafer dividing process.

[0007] The present invention has been made in consideration of the above problems, and has an object to provide a wafer processing tape that has good wafer separation properties when expanded in a temperature environment at or above room temperature, and a wafer processing method using the wafer processing tape. [Means for solving the problem]

[0008] The present inventors have conducted extensive research to solve the above problems, and as a result have found that the above problems can be solved by providing a wafer processing tape in which the adhesive layer has a predetermined storage modulus and the exposed surface on the back side of the base layer has a predetermined dynamic friction coefficient, thereby completing the present invention.

[0009] That is, the present invention is as follows. [1] a substrate layer having a front surface and a back surface; an adhesive layer laminated on the surface of the base material layer, the holding power of the adhesive layer against SUS304 under a load of 1000 g at 40°C is 10 to 130 hours; The storage modulus of the adhesive layer at 25°C is 1.0 × 10 5 ~1.0×10 6 Pa, Tape for wafer processing. [2] The shear adhesive strength of the adhesive layer to SUS304 at 25°C is 1100 to 2000 MPa. [1] The wafer processing tape according to [1]. [3] The substrate layer has an antistatic agent or an antistatic layer on the back surface side. [1] or [2]. The wafer processing tape according to [1] or [2]. [4] a bonding step of bonding the adhesive layer of the wafer processing tape according to any one of [1] to [3] to the surface of the wafer; a dicing step of laser dicing the wafer attached to the wafer processing tape to generate cracks inside the wafer; an expanding step of expanding the wafer by pushing up an expanding stage from the exposed surface side of the wafer processing tape to form the wafer into a die chip; a pick-up step of picking up the die chip from the wafer processing tape. Wafer processing method. [5] After the expanding step, the method further includes an irradiation step of irradiating the adhesive layer with ultraviolet light. [4] The wafer processing method according to [4]. [6] the surface of the wafer is a non-device-forming surface; The wafer processing method according to [4] or [5]. [7] the surface of the wafer is an element formation surface; The wafer processing method according to [4] or [5]. [8] a dicing step of generating a modified portion inside the wafer by laser dicing; a back-grinding step of grinding a non-element-formed surface of the wafer; a bonding step of bonding an adhesive layer of the wafer processing tape according to any one of [1] to [3] to the non-element-formed surface of the wafer; an expanding step of expanding the wafer processing tape by pushing up an expanding stage from the exposed surface side of the wafer processing tape; a pick-up step of picking up the die chip from the wafer processing tape. Wafer processing method. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a wafer processing tape that exhibits good divisibility when expanded in a temperature environment of room temperature or higher. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1(a) shows an example of a perspective view of the wafer processing tape of this embodiment, and FIG. 1(b) shows an example of a cross-sectional view taken along line AA' in FIG. 1(a). [Figure 2] FIG. 2(a) shows an example of a perspective view of the laser dicing process, and FIG. 2(b) shows an example of a cross-sectional view taken along line AA' in FIG. 2(a). [Figure 3] FIG. 3(a) shows an example of a perspective view of the back grinding process, and FIG. 3(b) shows an example of a cross-sectional view taken along line AA' in FIG. 3(a). [Figure 4] FIG. 4(a) shows an example of a perspective view of the bonding step, and FIG. 4(b) shows an example of a cross-sectional view taken along line AA' in FIG. 4(a). [Figure 5] FIG. 5(a) shows another example of a perspective view of the back grinding process, and FIG. 5(b) shows an example of a cross-sectional view taken along line AA' in FIG. 5(a). [Figure 6] FIG. 6(a) shows another example of a perspective view of the bonding step, and FIG. 6(b) shows an example of a cross-sectional view taken along line AA' in FIG. 6(a). [Figure 7] FIG. 7(a) shows another example of a perspective view of the laser dicing process, and FIG. 7(b) shows an example of a cross-sectional view taken along line AA' in FIG. 7(a). [Figure 8] FIG. 8(a) shows an example of a perspective view of the expanding step, and FIG. 8(b) shows an example of a cross-sectional view taken along line AA' in FIG. 8(a). [Figure 9] FIG. 9(a) shows an example of a perspective view of the heat shrink process, and FIG. 9(b) shows an example of a cross-sectional view taken along line AA' in FIG. 9(a). [Figure 10]FIG. 10(a) shows an example of a perspective view of the irradiation step, and FIG. 10(b) shows an example of a cross-sectional view taken along line AA' in FIG. 10(a). [Figure 11] FIG. 11(a) shows an example of a perspective view of the pick-up process, and FIG. 11(b) shows an example of a cross-sectional view taken along line AA' in FIG. 11(a). DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, an embodiment of the present invention (hereinafter referred to as "the present embodiment") will be described in detail with reference to the drawings as necessary, but the present invention is not limited to this, and various modifications are possible without departing from the spirit of the present invention. In the drawings, the same elements are given the same reference numerals, and redundant explanations will be omitted. Furthermore, positional relationships such as up, down, left, and right will be based on the positional relationships shown in the drawings unless otherwise specified. Furthermore, the dimensional ratios of the drawings are not limited to those shown in the drawings.

[0013] 1. Wafer processing tape The wafer processing tape of this embodiment has a base layer having a front surface and a back surface, and an adhesive layer laminated on the surface of the base layer, and the holding power of the adhesive layer against SUS304 under a load of 1000 g at 40°C is 10 to 130 hours, and the storage modulus of the adhesive layer at 25°C is 1.0 × 10 5 ~1.0×10 6 It is Pa.

[0014] Fig. 1(a) shows an example of a perspective view of the wafer processing tape of this embodiment, and Fig. 1(b) shows an example of a cross-sectional view taken along line A-A' in Fig. 1(a). As shown in Figs. 1(a) and 1(b), the wafer processing tape 100 of this embodiment has a base layer 101 and an adhesive layer 102 laminated on the front surface 101a of the base layer 101, and may also have a release liner layer 103 disposed on the adhesive layer 102 and an antistatic layer 104 disposed on the back surface 101b of the base layer 101.

[0015] 1(a) and 1(b), an embodiment having a base layer 101, an adhesive layer 102, and a release liner layer 103, or an embodiment having a base layer 101, an adhesive layer 102, and an antistatic layer 104 may be used. Furthermore, from the viewpoint of adhesion and adhesiveness between layers, an intermediate layer may be provided between the layers as needed.

[0016] Next, as a prerequisite for explaining the configuration of the wafer processing tape of this embodiment, a process of dividing the wafer 300 into die chips 303 by expanding will be explained. Fig. 5(a) shows an example of a perspective view of the expanding process, and Fig. 5(b) shows an example of a cross-sectional view taken along line A-A' in Fig. 5(a).

[0017] 5(a) and 5(b), in a temperature environment above room temperature, an expanding stage 402 is pushed up against the wafer processing tape 100 fixed to a ring frame 401, applying tension to the wafer processing tape 100 between the ring frame 401 and the wafer 300, causing the wafer processing tape 100 to expand in the planar direction. This force then divides the wafer 300 adhered to the wafer processing tape 100 at pre-installed modified sections 302, etc., to form individual die chips 303. This process is called the "expanding process." Temperature environments above room temperature include, for example, an environment of 25°C (room temperature) or 40°C.

[0018] In this way, in order to divide the wafer 300 into die chips 303 by expanding, it is necessary that the external force applied to the wafer processing tape 100 by the expanding stage 402 be efficiently transmitted to the wafer 300 .

[0019] From this perspective, in this embodiment, the storage modulus of the adhesive layer 102 in a temperature environment equal to or higher than room temperature is specified. This improves the tension (restoring force) applied to the wafer processing tape 100 between the ring frame 401 and the wafer 300 during the expanding process, improving the transferability of external forces to the wafer 300. This prevents defective division, such as division at the modified portion 302, and further improves division.

[0020] Furthermore, in the expanding step, by increasing the amount of expansion, the external force transmitted to the wafer 300 increases, and as a result, the wafer 300 becomes easier to separate by the die tip 303 .

[0021] From this perspective, in this embodiment, the holding force of the adhesive layer 102 on the SUS304 when a load of 1000 g is applied in a temperature environment above room temperature is specified. This makes it difficult for the wafer processing tape 100 to peel off from the ring frame 401, makes it possible to push up the expansion stage 402 by a larger amount in the expanding step, and increases the external force transmitted to the wafer 300. This prevents defective division, such as when the modified portion 302 does not divide, and further improves divisibility.

[0022] Each of the components of the wafer processing tape of this embodiment will be described in detail below.

[0023] 1.1. Base material layer The wafer processing tape 100 of this embodiment has a base layer 101 having a front surface 101a and a back surface 101b. The base layer 101 preferably contains a resin. The resin is not particularly limited, but examples thereof include ionomer resin, polyvinyl chloride, polyethylene terephthalate, ethylene-vinyl acetate copolymer, ethylene-acrylic acid-acrylic acid ester film, ethylene-ethyl acrylate copolymer, polyethylene, polypropylene, propylene-based copolymer, and ethylene-acrylic acid copolymer. These resins may be used alone or in combination of two or more. More specifically, the base layer 101 may be a mixture, copolymer, or laminate of one of these resins with another.

[0024] Ionomer resins have a cross-linked structure formed by metal ions, and therefore can maintain shape stability even when exposed to temporary or localized high temperatures, such as those encountered during semiconductor processing.

[0025] The ionomer resin is not particularly limited as long as it is a resin in which a predetermined polymer is intermolecularly bonded by a metal ion, and examples thereof include polyolefin-based ionomers, (meth)acrylic ionomers, polystyrene-based ionomers, and polyester-based ionomers. These ionomer resins may be used alone or in combination of two or more. Among these, polyolefin-based ionomers and (meth)acrylic ionomers are preferred, and (meth)acrylic ionomers are more preferred.

[0026] The polyolefin ionomer is not particularly limited, but examples thereof include ethylene-methacrylate copolymer, ethylene-acrylate copolymer, and ethylene-methacrylate-acrylate copolymer.

[0027] The (meth)acrylic ionomer is not particularly limited, but examples thereof include an acrylic acid ester-acrylate copolymer, an acrylic acid ester-methacrylate copolymer, a methacrylic acid ester-acrylate copolymer, and a methacrylic acid ester-methacrylate copolymer.

[0028] The polystyrene ionomer is not particularly limited, but examples thereof include a styrene-styrene sulfonate copolymer, a styrene-acrylate copolymer, a styrene-methacrylate copolymer, a styrene-styrene carboxylate copolymer, and a styrene-N-methyl 4-vinylpyridinium salt copolymer.

[0029] The polyester ionomer is not particularly limited, but examples thereof include sulfoterephthalic acid salt copolymerized polyethylene terephthalate, sulfoisophthalic acid salt copolymerized polyethylene terephthalate, sulfoterephthalic acid copolymerized polybutylene terephthalate, and sulfoisophthalic acid copolymerized polybutylene terephthalate.

[0030] The metal ions constituting the salt of the ionomer resin are not particularly limited, but examples thereof include monovalent metal ions such as sodium ions and lithium ions; divalent metal ions such as zinc ions, calcium ions, and magnesium ions; and trivalent metal ions such as aluminum ions, with zinc ions being preferred. The polymer and metal ions in the ionomer resin can be used in any combination based on the ionic functional group in the polymer and the valence of the metal ions.

[0031] The base layer 101 may contain an elastomer. Examples of the elastomer include, but are not limited to, natural rubber, butyl rubber, isoprene rubber, chloroprene rubber, silicone rubber, ethylene-vinyl acetate copolymer, ethylene-(meth)acrylic acid copolymer, ethylene-(meth)acrylic acid ester copolymer, polybutadiene resin, polycarbonate resin, thermoplastic polyimide resin, polyamide resin such as 6-nylon and 6,6-nylon, (meth)acrylic resin, polyester resin such as polyethylene terephthalate and polybutylene terephthalate, polyamideimide resin, fluororesin, and phenoxy resin. These elastomers may be used alone or in combination.

[0032] The content of the resin in the base material layer 101 is preferably 80 to 100 mass %, 85 to 98 mass %, or 90 to 95 mass %, based on the entire base material layer 101.

[0033] The base layer 101 may contain additives other than resins as needed. Examples of additives include, but are not limited to, plasticizers, heat stabilizers, colorants, organic lubricants, inorganic lubricants, surfactants, processing aids, and antistatic agents. The additives may be used alone or in combination.

[0034] The content of the additive with respect to the entire base material layer 101 is preferably 0.1 to 10.0 mass %, 0.5 to 5.0 mass %, or 1.0 to 2.5 mass %.

[0035] The antistatic agent is not particularly limited, but examples thereof include carbon nanotubes, metal oxides, polythiophene, polyaniline, polypyrrole, dimethylaminoethyl (meth)acrylate quaternary chloride, diethylaminoethyl (meth)acrylate quaternary chloride, methylethylaminoethyl (meth)acrylate quaternary chloride, p-dimethylaminostyrene quaternary chloride, p-diethylaminostyrene quaternary chloride, acrylic polymers having quaternary ammonium salts in their side chains, and quaternary ammonium salt-type acrylic polymers. The antistatic agents may be used alone or in combination of two or more.

[0036] The friction reducer is not particularly limited, but examples thereof include silicone resins, fluororesins, (modified) silicone oils, waxes, fatty acid esters, and fatty acid amides. These friction reducers may be used as a mixture of multiple components. Silicone graft copolymers are particularly preferred.

[0037] Examples of silicone graft copolymers include vinyl polymers obtained by polymerizing a monomer having a vinyl group such as a (meth)acryloyl group or a styryl group at the end of the silicone molecular chain (hereinafter referred to as a "silicone monomer") with a (meth)acrylic monomer, a monomer having a vinyl group such as styrene, or the like.

[0038] Examples of the (meth)acrylic monomer used in the silicone graft copolymer include alkyl (meth)acrylate, hydroxyalkyl (meth)acrylate, modified hydroxy (meth)acrylate, and (meth)acrylic acid, with alkyl (meth)acrylate being preferred.

[0039] Examples of alkyl (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, n-propyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, t-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, and isobornyl (meth)acrylate, as well as hydroxyalkyl (meth)acrylates.

[0040] Examples of the hydroxyalkyl (meth)acrylate include hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, and hydroxybutyl (meth)acrylate.

[0041] Examples of modified hydroxy(meth)acrylates include ethylene oxide-modified hydroxy(meth)acrylates and lactone-modified hydroxy(meth)acrylates.

[0042] The thickness of the base layer 101 is preferably 10 to 500 μm, 25 to 250 μm, or 50 to 100 μm. When the thickness of the base layer 101 is within the above range, the external force applied to the wafer processing tape during the expanding process is more easily transmitted to the wafer 300, which tends to result in improved divisibility of the wafer 300.

[0043] The substrate layer 101 may be a single layer or multi-layer structure comprising the materials mentioned above.

[0044] 1.2.Adhesive layer The wafer processing tape 100 of this embodiment has an adhesive layer 102 laminated on the surface of a base layer 101. The adhesive layer 102 contributes to the adhesion between the base layer 101 and the wafer 300. It is preferable that the adhesive layer 102 maintains the adhesion between the base layer 101 and the wafer 300 until the pick-up step so that the die chip 303 does not fall off. On the other hand, in the pick-up step, it is preferable that the adhesive strength to the wafer 300 is low from the viewpoint of improving the pick-up ability of the die chip 303.

[0045] From this perspective, in order to change the adhesive strength depending on the irradiation process, the adhesive layer 102 may contain a base polymer having a polymerizable carbon-carbon double bond and a photopolymerization initiator, or may contain a base polymer, an oligomer having a polymerizable carbon-carbon double bond, and a photopolymerization initiator, or may further contain an additive such as a curing agent. In this way, when the adhesive layer 102 is irradiated with ultraviolet light, the photopolymerization initiator generates radicals, which polymerize each of the components having polymerizable carbon-carbon double bonds contained in the adhesive layer 102. As a result, after ultraviolet light irradiation, the components in the adhesive layer 102 are crosslinked with each other, and the adhesive strength decreases.

[0046] In this embodiment, the adhesive layer 102 preferably contains a base polymer having a polymerizable carbon-carbon double bond, an oligomer having a polymerizable carbon-carbon double bond and an isocyanate group, a photoinitiator, and a curing agent that is an isocyanate-based compound. The adhesive layer 102 may contain these components in a reacted state. Specifically, the adhesive layer 102 may undergo three reactions to form a crosslinked body: a reaction in which the curing agent reacts with carboxyl groups, etc., of the base polymer to crosslink the base polymers; a reaction between isocyanate groups of the oligomers; and a reaction between the isocyanate groups of the base polymer that have reacted with the curing agent and the isocyanate groups of the oligomer.

[0047] Furthermore, when the adhesive layer 102 contains a base polymer having a polymerizable carbon-carbon double bond, an oligomer having a polymerizable carbon-carbon double bond and an isocyanate group, a photoinitiator, and a curing agent that is an isocyanate compound, it is preferable that the above-mentioned three reactions have progressed at the stage of irradiating the adhesive layer 102 with ultraviolet light. In other words, it is preferable that no unreacted isocyanate groups exist in the adhesive layer 102 at the stage of irradiating such adhesive layer 102 with ultraviolet light.

[0048] The adhesive layer 102 may be disposed only on the portion of the wafer processing tape 100 where the wafer 300 is disposed, or the adhesive layer 102 may be formed in other portions than the above-mentioned portion.

[0049] 1.2.1. Base polymer The base polymer is a component that constitutes the main component of the adhesive layer 102. The base polymer is not particularly limited, but examples thereof include (meth)acrylic acid ester copolymers that may have polymerizable double bonds. The shape of the (meth)acrylic acid ester copolymer is not particularly limited, but examples thereof include linear, branched, or crosslinked shapes. Among these, a crosslinked shape is preferable. By using such a base polymer, the cohesive force of the adhesive layer 102 is improved, the adhesion to the wafer is further improved, and contamination tends to be further reduced. A base polymer having a crosslinked or branched shape may be a base polymer having a linear shape, in which some of the polymerizable double bonds have been bonded by aging or the like.

[0050] The (meth)acrylic acid ester copolymer may contain a carboxyl group-containing monomer, which is not particularly limited, but includes, for example, acrylic acid, methacrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid.

[0051] The (meth)acrylic acid ester monomer constituting the (meth)acrylic acid ester copolymer is not particularly limited, and examples thereof include alkyl (meth)acrylates having a linear or branched alkyl group such as methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, isobutyl, amyl, isoamyl, hexyl, heptyl, cyclohexyl, 2-ethylhexyl, octyl, isooctyl, nonyl, isononyl, decyl, isodecyl, undecyl, lauryl, tridecyl, tetradecyl, stearyl, octadecyl, and dodecyl. These alkyl (meth)acrylates may be used alone or in combination of two or more.

[0052] Furthermore, the monomer components other than the alkyl (meth)acrylate are not particularly limited, and examples thereof include acid anhydride monomers such as maleic anhydride and itaconic anhydride; hydroxyl group-containing monomers such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 1-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, and (4-hydroxymethylcyclohexyl)methyl (meth)acrylate; sulfonic acid group-containing monomers such as styrenesulfonic acid, allylsulfonic acid, 2-(meth)acrylamido-2-methylpropanesulfonic acid, (meth)acrylamidopropanesulfonic acid, sulfopropyl (meth)acrylate, and (meth)acryloyloxynaphthalenesulfonic acid; and phosphoric acid group-containing monomers such as 2-hydroxyethyl acryloyl phosphate. These other monomers may be used alone or in combination of two or more.

[0053] Among these, a (meth)acrylic acid ester copolymer containing an alkyl (meth)acrylate and a carboxyl group-containing monomer, and a (meth)acrylic acid ester copolymer containing an alkyl (meth)acrylate and a hydroxyl group-containing monomer are preferred.

[0054] When a polymerizable double bond is introduced into a (meth)acrylic acid ester copolymer, the method therefor is not particularly limited, and examples thereof include a method in which a modifying agent having a polymerizable double bond is reacted with a carboxyl group of a carboxyl group-containing monomer, a carboxyl anhydride group of an acid anhydride monomer, or a hydroxyl group of a hydroxyl group-containing monomer.

[0055] By reacting an isocyanate compound having a polymerizable double bond as a modifier with a (meth)acrylic acid ester copolymer containing a carboxyl group-containing monomer unit, a polymerizable double bond can be introduced into the carboxyl group-containing monomer unit via an amide bond. As another example, by reacting an epoxy compound having a polymerizable double bond as a modifier with a (meth)acrylic acid ester copolymer containing a carboxyl group-containing monomer unit, a polymerizable double bond can be introduced into the carboxyl group-containing monomer unit via an ester bond.

[0056] In addition, for example, by reacting an isocyanate compound having a polymerizable double bond as a modifier with a (meth)acrylic acid ester copolymer containing a hydroxyl group-containing monomer unit, a polymerizable double bond can be introduced into the hydroxyl group-containing monomer unit via a urethane bond.

[0057] The modifier is not particularly limited as long as it has a functional group such as an isocyanate group that reacts with the functional group of the (meth)acrylic acid ester copolymer and a polymerizable double bond, and examples thereof include oligomers described below.

[0058] The weight average molecular weight of the base polymer is preferably 5.0×10 4 ~2.0×10 6 is 1.0 × 10 5 ~1.0×10 6 is 1.5 × 10 5 ~5.0×10 5When the weight average molecular weight of the base polymer is within the above range, the divisibility during expansion in a temperature environment of room temperature or higher tends to be further improved.

[0059] In addition, the weight average molecular weight of the base polymer is 1.0 × 10 4 By having a weight average molecular weight of 2.0 x 10 or more, the amount of high molecular weight components increases, and the higher the molecular weight, the more opportunities there are for one base polymer to polymerize with another base polymer via polymerizable double bonds, which tends to further reduce contamination. 6 By having a molecular weight of 0.01 or less, the base polymer is more mobile, increasing the opportunities for one base polymer to polymerize with another, which tends to further reduce contamination. Furthermore, the smaller the molecular weight, the less the adhesive's elastic modulus becomes excessively high, which tends to improve adhesive strength under normal conditions. Furthermore, since it has better conformability to the wafer and can follow unevenness in the wafer, contamination due to poor UV curing caused by oxygen inhibition can be avoided. Furthermore, soft adhesives are easily cured and shrink when exposed to UV light, which allows for a sufficient reduction in adhesive strength after curing.

[0060] The "weight average molecular weight" described in this specification is the molecular weight measured by using a gel permeation chromatograph analyzer for a sample prepared by dissolving the base polymer in tetrahydrofuran.

[0061] The glass transition point of the base polymer is preferably -50 to 10°C, -40 to 0°C, or -30 to -10°C. When the glass transition point of the base polymer is within the above range, the divisibility during expansion in a temperature environment of room temperature or higher tends to be further improved. When the glass transition point of the base polymer is -50°C or higher, contamination tends to be further reduced. When the glass transition point of the base polymer is 10°C or lower, the adhesion to the wafer tends to be further improved.

[0062] The content of the base polymer is preferably 20 to 50 mass %, 25 to 45 mass %, or 30 to 40 mass % relative to the total amount of the adhesive layer 102. When the content of the base polymer is within the above range, the divisibility during expansion in a temperature environment of room temperature or higher tends to be further improved.

[0063] As mentioned above, the base polymers may be crosslinked with each other by a curing agent described later. Specifically, an isocyanate compound (curing agent) having two or more isocyanate groups may react with carboxyl groups, hydroxyl groups, or the like of two or more base polymers, respectively, to form a crosslinked body in which the base polymers are crosslinked via the curing agent.

[0064] Oligomers The adhesive layer 102 of this embodiment may contain an oligomer. In this embodiment, the oligomer refers to a polymer in which multiple monomers are bonded together, and may have a polymerizable carbon-carbon double bond. More specifically, the oligomer may be formed by polymerizing multiple polyfunctional monomers each having multiple polymerizable carbon-carbon double bonds, and may still have polymerizable carbon-carbon double bonds after polymerization.

[0065] The weight average molecular weight of the oligomer is preferably 3.0×10 3 ~1.75×10 5 is 4.0 × 10 3 ~1.5×10 5 is 5.0 × 10 3 ~1.25×10 5 When the weight average molecular weight is within the above range, the divisibility during expansion in a temperature environment of room temperature or higher tends to be further improved.

[0066] The polymerizable carbon-double bond group equivalent weight, such as the acrylic group equivalent weight, of the oligomer is preferably 50 to 2500 eq / g, 75 to 2000 eq / g, or 100 to 1500 eq / g. When the carbon-double bond group equivalent weight is within the above range, the divisibility during expansion in a temperature environment of room temperature or higher tends to be further improved.

[0067] Such oligomers are not particularly limited, but examples thereof include urethane oligomers, acrylic oligomers, epoxy oligomers, and silicone oligomers, with acrylic oligomers being preferred.

[0068] The monomer constituting the acrylic oligomer is not particularly limited, but examples thereof include polyfunctional monomers having a plurality of polymerizable carbon double bond groups, such as dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, polyethylene adipate having ethyl acrylate at both ends, and poly-1,4-butylene adipate having ethyl acrylate at both ends; and monomers having an isocyanate group, such as an adduct of isophorone diisocyanate trimer (IPDI trimer) and dipentaerythritol pentaacrylate, and an adduct of 2-hydroxyethyl acrylate and IPDI.

[0069] The oligomer may have an isocyanate group. In particular, the isocyanate group can be introduced into the oligomer by using a monomer having an isocyanate group. Other methods include, but are not limited to, a method of reacting a carboxyl group of a carboxyl group-containing monomer, a carboxyl anhydride group of an acid anhydride monomer, or a hydroxyl group of a hydroxyl group-containing monomer with a modifier having multiple isocyanate groups.

[0070] By reacting an isocyanate compound having two or more isocyanate groups as a modifying agent with an oligomer having a hydroxyl group, it is possible to introduce an isocyanate group into the oligomer via a urethane bond.

[0071] Alternatively, for example, an isocyanate compound having two or more isocyanate groups as a modifying agent can be reacted with an oligomer having a carboxyl group to introduce an isocyanate group into the oligomer via an amide bond.

[0072] The content of the oligomer relative to the total amount of adhesive layer 102 is preferably 35 to 75 mass %, 40 to 70 mass %, or 45 to 65 mass %.

[0073] 1.2.3. Photopolymerization initiator The photopolymerization initiator is not particularly limited, but examples thereof include alkylphenone-based photopolymerization initiators, acylphosphine oxide-based photopolymerization initiators, thioxanthone-based photopolymerization initiators, aromatic ketones, aromatic onium salt compounds, organic peroxides, thio compounds (e.g., thiophenyl group-containing compounds), α-aminoalkylphenone compounds, hexaarylbiimidazole compounds, ketoxime ester compounds, borate compounds, azinium compounds, metallocene compounds, active ester compounds, compounds having a carbon-halogen bond, and alkylamine compounds. Among these, alkylphenone-based photopolymerization initiators are preferred. These photopolymerization initiators may be used alone or in combination of two or more.

[0074] The content of the photopolymerization initiator is preferably 0.1 to 5.0 mass %, 0.2 to 4.5 mass %, or 0.3 to 4.0 mass % relative to the total amount of the adhesive layer 102. When the content of the photopolymerization initiator is within the above range, contamination tends to be further suppressed.

[0075] Additives The adhesive layer 102 may contain additives such as a curing agent, a tackifier, a crosslinking retarder, and an antioxidant.

[0076] The curing agent is not particularly limited, but examples thereof include isocyanate-based compounds, epoxy-based compounds, and amine-based compounds. Among these, isocyanate-based compounds are preferred. Use of such curing agents tends to further improve the cohesive strength of the adhesive layer 102. These curing agents may be used alone or in combination of two or more.

[0077] The isocyanate compound is not particularly limited, and examples thereof include compounds having a group that reacts with the hydroxyl group or carboxyl group of the base polymer. More specific examples include tolylene diisocyanates such as trimethylolpropane-added tolylene diisocyanate, aromatic diisocyanates such as 4,4-diphenylmethane diisocyanate and xylylene diisocyanate, alicyclic diisocyanates such as isophorone diisocyanate and methylene bis(4-cyclohexyl isocyanate), and aliphatic diisocyanates such as hexamethylene diisocyanate and trimethylhexamethylene diisocyanate. These isocyanate compounds may be used alone or in combination of two or more.

[0078] Among these, a polyfunctional isocyanate compound having two or more functional groups is preferred as the curing agent. By using such a curing agent, the curing agent can also crosslink multiple base polymers, which tends to further improve the cohesive strength of the adhesive layer 102. In addition, the anchoring ability between the substrate layer and the adhesive layer 102 also improves, which tends to result in more stable adhesive properties.

[0079] The content of the curing agent is preferably 5.0 to 25.0 parts by mass, more preferably 7.5 to 22.5 parts by mass, and even more preferably 10.0 to 20.0 parts by mass, relative to 100 parts by mass of the base polymer. When the content of the curing agent is 5.0 parts by mass or more, the crosslink density of the adhesive layer 102 is further improved, cohesive failure that occurs during peeling is further suppressed, and contamination due to cohesive failure tends to be further suppressed. Furthermore, when the content of the curing agent is 25.0 parts by mass or less, the crosslink density is further reduced, and the elastic modulus is lowered, which tends to further improve adhesive strength.

[0080] The content of the curing agent is preferably 1.0 to 10.0 mass %, 2.0 to 9.0 mass %, or 3.0 to 8.0 mass % relative to the total amount of the adhesive layer 102. When the content of the curing agent is within the above range, contamination tends to be further suppressed.

[0081] The tackifier is not particularly limited, but examples thereof include petroleum-based resins, terpene resins, terpene-phenolic resins, aromatic-modified terpene resins, coumarone-indene resins, natural resin rosin, modified rosin, glycerin ester rosin, pentaerythritol ester rosin, phenolic resins, xylene resins, alicyclic petroleum resins, styrene-based resins, and dicyclopentadiene resins. These tackifiers may be used alone or in combination. The content of the tackifier is preferably 0.1 to 2.0 mass%, 0.2 to 1.5 mass%, or 0.3 to 1.0 mass% relative to the total amount of the adhesive layer 102.

[0082] The crosslinking retarder is not particularly limited, but may be, for example, a compound that can suppress excessive viscosity increase in a pressure-sensitive adhesive composition containing an isocyanate-based curing agent by blocking the isocyanate groups of the curing agent. Examples of such crosslinking retarders include, but are not limited to, β-diketones such as acetylacetone, hexane-2,4-dione, heptane-2,4-dione, and octane-2,4-dione; β-ketoesters such as methyl acetoacetate, ethyl acetoacetate, propyl acetoacetate, butyl acetoacetate, octyl acetoacetate, oleyl acetoacetate, lauryl acetoacetate, and stearyl acetoacetate; and benzoylacetone. These crosslinking retarders may be used alone or in combination. The content of the crosslinking retarder is preferably 0.1 to 2.0 mass%, 0.2 to 1.5 mass%, or 0.3 to 1.0 mass% relative to the total amount of the adhesive layer 102.

[0083] The antioxidant is not particularly limited, but examples thereof include methylhydroquinone, hydroquinone, 2,2-methylene-bis(4-methyl-6-tert-butylphenol), catechol, hydroquinone monomethyl ether, monotert-butylhydroquinone, 2,5-ditert-butylhydroquinone, p-benzoquinone, 2,5-diphenyl-p-benzoquinone, 2,5-ditert-butyl-p-benzoquinone, picric acid, citric acid, phenothiazine, tert-butylcatechol, 2-butyl-4-hydroxyanisole, 2,6-ditert-butyl-p-cresol, and 4-[[4,6-bis(octylthio)-1,3,5-triazin-2-yl]amino]-2,6-ditert-butylphenol. These antioxidants may be used alone or in combination. The content of the antioxidant relative to the total amount of the adhesive layer 102 is preferably 0.1 to 2.0 mass %, 0.2 to 1.5 mass %, or 0.3 to 1.0 mass %.

[0084] The thickness of the adhesive layer 102 is usually 1.0 to 250 μm, preferably 2.0 to 50 μm, and more preferably 5.0 to 40 μm. By making the thickness of the adhesive layer 102 1.0 μm or more, sufficient adhesive strength can be ensured, making it easier to prevent the scattering of semiconductor chips separated by expanding. Furthermore, by making the thickness of the adhesive layer 250 μm or less, costs tend to be further reduced.

[0085] The holding power of adhesive layer 102 to SUS304 under a load of 1000 g at 40° C. is 10 to 130 hours, preferably 30 to 130 hours, and more preferably 60 to 130 hours. When the holding power at 40° C. is within the above range, the divisibility of wafer 300 tends to be further improved.

[0086] The holding power of adhesive layer 102 against SUS304 at 40° C. when a load of 1000 g is applied can be adjusted by the type and composition of the resin that constitutes adhesive layer 102.

[0087] The storage modulus of the adhesive layer 102 at 25°C is 1.0 × 10 5 ~1.0×10 6 Pa, preferably 1.5 x 10 5 ~9.0×10 5 Pa, 2.0 x 10 5 ~8.0×10 5 Pa, 2.5 x 10 5 ~7.0×10 5 Pa, 3.0 x 10 5 ~6.0×10 5 Pa. When the storage modulus at 25° C. is within the above range, the divisibility of the wafer 300 tends to be further improved.

[0088] The storage modulus of the adhesive layer 102 at 25° C. can be adjusted by the type and composition of the resin that constitutes the adhesive layer 102 .

[0089] The shear bond strength of the adhesive layer 102 to SUS304 at 25°C is preferably 1100 to 2000 MPa, 1200 to 1800 MPa, or 1300 to 1600 MPa. When the shear bond strength at 25°C is within the above range, the wafer processing tape 100 is less likely to peel off from the ring frame 401, making it possible to push up the expanding stage 402 by a larger amount in the expanding step, and increasing the external force transmitted to the wafer 300. This tends to suppress poor separation, such as failure to separate at the modified portion 302, and to further improve detachability.

[0090] The shear adhesive strength of adhesive layer 102 to SUS304 at 25° C. can be adjusted by the type and composition of the resin that constitutes adhesive layer 102.

[0091] In this embodiment, the holding force of the adhesive layer 102 under a load of 1000 g and the shear bond strength of the adhesive layer 102 against SUS304 are measured. Depending on the specifications of the expanding device, the expanding stage, which is the base on which the dicing tape is placed during expanding, may be made of a material other than SUS304, such as martensitic stainless steels such as SUS410, SUS403, and SUS630, austenitic stainless steels such as SUS303 and SUS316, ferritic stainless steels such as SUS430, or other metals. However, the trends in the holding force and shear bond strength of the adhesive layer 102 against SUS304 are similar to those of other stainless steels and metals. Therefore, if the holding force and shear bond strength of the adhesive layer 102 under a load of 1000 g, measured based on SUS304, fall within a predetermined range, the divisibility of the wafer 300 is improved.

[0092] In this embodiment, 25°C may be used as a reference value for the temperature during expansion. Depending on the specifications of the expanding device, it is expected that expansion may be performed at a temperature higher or lower than 25°C. However, even if the actual temperature during expansion is not 25°C but is higher or lower than this, it can be said that the divisibility of the wafer 300 is improved if the storage modulus and shear bond strength measured with 25°C as the reference satisfy the predetermined ranges. Unless otherwise specified, in this specification, the storage modulus and shear bond strength refer to values ​​measured at 25°C.

[0093] In this embodiment, 40°C may be used as a reference value for the temperature during expansion. Depending on the specifications of the expanding equipment, it is conceivable that expansion may be performed at a temperature higher or lower than 40°C. However, even if the actual temperature during expansion is not 40°C but is higher or lower than this, it can be said that the divisibility of the wafer 300 is improved if the retention force measured with 40°C as the reference falls within a predetermined range. Unless otherwise specified, in this specification, retention force means that measured at 40°C.

[0094] The holding power is measured in accordance with JIS Z0237:2009, except that the temperature condition is 40°C.

[0095] The storage modulus is measured in accordance with the storage modulus in shear mode described in JIS K7244-1:1998, except that the temperature condition is 25°C.

[0096] The shear bond strength is measured in accordance with JIS K6852:1994, except that the temperature condition is 25°C.

[0097] 1.3.Release Liner Layer The wafer processing tape 100 of this embodiment may have a release liner layer 103 on the adhesive layer 102. The release liner layer 103 protects the adhesive layer 102 before the wafer 300 is attached. Furthermore, the release liner layer 103 is peeled off from the adhesive layer 102 when the wafer 300 is attached.

[0098] The release liner layer 103 may be made from various materials, or a commercially available release liner product may be used. When making the release liner layer 103, the main material is not particularly limited, but examples thereof include polyethylene terephthalate (PET) resin film, polyethylene (PE) resin film, polypropylene (PP) resin film, PE-coated paper, and glassine paper.

[0099] The thickness of release liner layer 103 is not particularly limited, but is, for example, 10 to 100 μm.

[0100] 1.4.Antistatic layer The wafer processing tape 100 of this embodiment may have an antistatic layer 104 on the back surface side of the base layer 101. The antistatic layer 104 may be a layer composed of only an antistatic agent, a layer composed of an antistatic agent and other components, or a layer containing an antistatic agent and other components in a matrix such as an organic binder. Examples of other components include a friction reducer.

[0101] 1.4.1. Organic binders The organic binder is not particularly limited, but examples thereof include acrylic resins, urethane resins, polyester resins, epoxy resins, polyvinyl chloride resins, melamine resins, polyimide resins, and silicone resins.

[0102] The acrylic resin is a polymer of a vinyl compound having (meth)acrylic acid monomer units or (meth)acrylic acid ester monomer units. The acrylic resin may also have monomer units derived from functional group-containing monomers such as styrene, vinyl toluene, allyl acetate, (meth)acrylonitrile, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl versatate, vinyl ethyl ether, vinyl propyl ether, and vinyl isobutyl ether.

[0103] The (meth)acrylic acid ester monomer is not particularly limited, but examples thereof include butyl (meth)acrylate, 2-butyl (meth)acrylate, t-butyl (meth)acrylate, pentyl (meth)acrylate, octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl (meth)acrylate, lauryl (meth)acrylate, methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, tridecyl (meth)acrylate, myristyl (meth)acrylate, cetyl (meth)acrylate, stearyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, etc. A plurality of (meth)acrylic acid ester monomers may be used in combination.

[0104] The functional group-containing monomer is not particularly limited, but examples thereof include monomers having a functional group such as a hydroxyl group, a carboxyl group, an epoxy group, an amide group, an amino group, a methylol group, a sulfonic acid group, a sulfamic acid group, or a phosphate (or phosphorous) ester group.

[0105] Examples of the monomer having a hydroxyl group include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 2-hydroxybutyl (meth)acrylate.

[0106] Examples of the monomer having a carboxyl group include (meth)acrylic acid, crotonic acid, maleic acid, maleic anhydride, itaconic acid, fumaric acid, acrylamido-N-glycolic acid, and cinnamic acid.

[0107] Examples of the monomer having an epoxy group include allyl glycidyl ether and (meth)acrylic acid glycidyl ether.

[0108] Examples of monomers having an amide group include (meth)acrylamide. Examples of monomers having an amino group include N,N-dimethylaminoethyl (meth)acrylate. Examples of monomers having a methylol group include N-methylolacrylamide. A plurality of functional group-containing monomers may be used in combination.

[0109] In addition to the above monomers, for example, styrene, vinyl toluene, allyl acetate, (meth)acrylonitrile, vinyl acetate, vinyl propionate, vinyl butyrate, vinyl versatate, vinyl ethyl ether, vinyl propyl ether, vinyl isobutyl ether, etc. may be appropriately used in the (meth)acrylic acid ester polymer.

[0110] 1.4.2. Antistatic Agents The antistatic agent is not particularly limited, but examples thereof include those exemplified as additives for the base layer.

[0111] When the antistatic agent is a substance having adhesiveness such that the antistatic agent alone can adhere to the substrate, such as a quaternary ammonium salt-type acrylic polymer, an organic binder is not required, and the antistatic layer 104 may consist solely of the antistatic agent, or may consist of the antistatic agent and other components such as a friction reducer. On the other hand, when the antistatic agent is a substance such as carbon nanotubes that cannot adhere to the substrate alone, the antistatic layer 104 preferably contains an organic binder. When the antistatic layer 104 contains an organic binder, the content of the antistatic agent in the antistatic layer 104 is preferably 0.01 to 15.00 parts by mass per 100 parts by mass of the organic binder, from the viewpoint of exerting a sufficient antistatic effect.

[0112] 1.4.3.Friction reducers The friction reducer is not particularly limited, but examples thereof include those exemplified as additives for the base layer.

[0113] The content of the friction reducing agent in the antistatic layer 104 is preferably 1.0 to 10.0 mass %, and more preferably 2.5 to 7.5 mass %, based on the total mass of the antistatic layer 104.

[0114] When the antistatic layer 104 contains components other than those described above, the other components are not particularly limited, and examples thereof include acrylic polymers such as (meth)acrylic acid ester polymers and acrylic graft polymers, urethane polymers, polyester polymers, epoxy polymers, polyvinyl chloride polymers, melanin polymers, polyimide polymers, and silicone polymers. The other components may be used alone or in combination of two or more. More specifically, an acrylic polymer may be an acrylic-silicone copolymer.

[0115] The content of other components in the antistatic layer 104 is not particularly limited, but is, for example, 0.1 to 10.0 mass %. Alternatively, the antistatic layer 104 may not contain other components.

[0116] The antistatic layer 104 may contain various additives such as a hardener, a plasticizer, an antioxidant, and a filler.

[0117] The thickness of the antistatic layer 104 is preferably 0.01 to 1 μm, more preferably 0.02 to 0.7 μm, from the viewpoint of exerting a sufficient antistatic effect.

[0118] 2. Manufacturing method of wafer processing tape The method for producing the wafer processing tape 100 of this embodiment is not particularly limited, but the following method may be mentioned, for example.

[0119] The means for forming the base layer 101 is not particularly limited, but the above-mentioned various materials are mixed using a conventional melt kneader or various mixing devices (single-screw or twin-screw extruder, roll, Banbury mixer, various kneaders, etc.) so that the components are uniformly dispersed, and the mixture is formed into the base by a T-die method, a calendar method, or an inflation method. Preferably, the T-die method using an extruder with good thickness accuracy is used.

[0120] The means for forming adhesive layer 102 is not particularly limited, but may be such that the various materials described above are dissolved in a solvent such as an organic solvent to form a varnish, which is then applied to base layer 101 by knife coating, roll coating, spray coating, gravure coating, bar coating, curtain coating, or the like, and the solvent is removed to form adhesive layer 102. Alternatively, the various materials described above in the form of a varnish may be applied to a molding film, the solvent may be removed to form adhesive layer 102, and this may be attached to base layer 101 to form adhesive layer 102 on base layer 101.

[0121] The means for forming the antistatic layer 104 is not particularly limited, but the above-mentioned various materials may be dissolved in a solvent such as an organic solvent to form a varnish, which may then be applied to the back surface 101b of the base layer 101 to form the antistatic layer 104. Alternatively, the antistatic layer 104 may be formed on a molding film 200, which may then be laminated on the back surface 101b of the base layer 101, thereby forming the antistatic layer 104 on the base layer 101.

[0122] 3. Wafer processing method The wafer processing method using the wafer processing tape 100 of this embodiment may include a bonding process s203 in which the adhesive layer 102 of the wafer processing tape 100 is bonded to the surface of the wafer 300, a laser dicing process s201 in which the wafer 300 bonded to the wafer processing tape 100 is laser diced to create a modified portion inside the wafer, an expanding process s204 in which the wafer 300 is expanded by pushing up the expand stage 402 from the exposed surface 100b side of the wafer processing tape 100 to form the die chip 303, and a pick-up process s207 in which the die chip 303 is picked up from the wafer processing tape 100.

[0123] In addition, the wafer processing method using the wafer processing tape 100 of this embodiment may include a laser dicing process s201 in which a modified portion 302 is generated inside the wafer 300 by laser dicing, a backgrinding process s202 in which a non-element forming surface 300b of the wafer 300 is ground, a bonding process s203 in which the adhesive layer 102 of the wafer processing tape 100 is bonded to the non-element forming surface 300b of the wafer 300, an expanding process s204 in which the wafer 300 is expanded by pushing up the expand stage 402 from the exposed surface 100b side of the wafer processing tape 100 to form the die chip 303, and a pick-up process s207 in which the die chip 303 is picked up from the wafer processing tape 100.

[0124] The wafer 300 is not particularly limited, but may be, for example, a conventional general-purpose semiconductor wafer such as a silicon wafer, a gallium nitride wafer, a silicon carbide wafer, a sapphire wafer, etc. The non-element-formed surface 300b of the wafer 300 refers to the surface of both sides of the wafer 300 on which elements 301 such as circuits are not formed, and the element-formed surface 300a of the wafer 300 refers to the surface of both sides of the wafer 300 on which elements 301 such as circuits are formed.

[0125] Each step of the wafer processing method of this embodiment will be described in detail below.

[0126] 3.1.Laser dicing process Fig. 2(a) shows an example of a perspective view of the laser dicing step s201, and Fig. 2(b) shows an example of a cross-sectional view taken along line A-A' in Fig. 2(a). The dashed lines in Fig. 2 indicate the path of the laser irradiated area, and in the subsequent expanding step, division occurs at the dashed line portions to form die chips 303.

[0127] 2(a) and 2(b), in the laser dicing step s201, a laser is irradiated onto the wafer 300 to generate a modified region 302 inside the wafer 300. More specifically, in the laser dicing step, it is preferable to perform stealth dicing, in which a pulsed laser is focused inside the wafer 300 to form the modified region 302 inside the wafer 300. At this time, it is preferable that the modified region 302 does not appear on the surface of the wafer 300.

[0128] The laser source is not particularly limited, but examples thereof include ultraviolet lasers, visible light lasers, near-infrared lasers, and far-infrared lasers. More specifically, for example, an Nd:YAG laser can be used.

[0129] The surface of the wafer 300 that is irradiated with the laser may be the non-element-formed surface 300b or the element-formed surface 300a.

[0130] 2(a) and 2(b), in the laser dicing step s201, the wafer 300 may be irradiated with a laser while the wafer 300 is attached to the backgrinding tape 200. After this, a backgrinding step is performed, which makes it easier to divide the wafer 300 in the modified section 302. Note that the tape used in the laser dicing step s201 is not limited to the backgrinding tape 200, and the wafer processing tape 100 of this embodiment or a known tape capable of fixing the wafer 300 may also be used.

[0131] In the following, the laser dicing step s201 may be performed before or after the back grinding step s202. Also, the laser dicing step s201 may be performed before or after the bonding step s203.

[0132] 3.2.Back grinding process Fig. 3(a) shows an example of a perspective view of the back-grinding step s202, and Fig. 3(b) shows an example of a cross-sectional view taken along line A-A' in Fig. 3(a). As shown in Figs. 3(a) and 3(b), in the back-grinding step s202, the non-element forming surface 300b of the wafer 300 is ground to thin the wafer 300.

[0133] Specifically, with the backgrind tape 200 attached to the element forming surface 300a from the viewpoint of protecting the element forming surface 300a, the non-element forming surface 300b of the wafer 300 is ground (backgrinded) to a position that reaches the modified portion 302 or a position close to the modified portion 302. This makes it easier to divide the wafer 300 into die chips 303 in the expanding step s204.

[0134] The back-grinding step s202 may be performed before or after the laser dicing step s201. Moreover, the back-grinding step s202 may be performed before or after the bonding step s203 described below.

[0135] 3.3. Bonding process Fig. 4(a) shows an example of a perspective view of the bonding step s203, and Fig. 4(b) shows an example of a cross-sectional view taken along line A-A' in Fig. 4(a). As shown in Figs. 4(a) and 4(b), in the bonding step s203, the adhesive layer 102 of the wafer processing tape 100 is bonded to the surface of the wafer 300. At this time, the surface of the wafer 300 to which the wafer processing tape 100 is bonded may be either the non-element-forming surface 300b or the element-forming surface 300a.

[0136] As shown in FIG. 4, the wafer 300 may already have a modified portion 302 formed therein by the laser dicing process s201, or, although not shown, the wafer 300 may not have a modified portion 302 therein.

[0137] The laminating step s203 of this embodiment may be performed using a known device or manually, such as, but not limited to, DFM2800 manufactured by Disco Corporation.

[0138] The above-mentioned laser dicing step s201, back grinding step s202, and bonding step s203 may be performed in any order.

[0139] For example, in a mode in which the wafer processing tape of this embodiment is used as a transfer tape, after forming a modified portion by laser dicing (s201), a backgrind tape is attached to the element forming surface 300a, and the non-element forming surface 300b is backgrinded (s202), and finally the wafer processing tape of this embodiment is attached to the non-element forming surface 300b (s203), and the backgrind tape is peeled off from the element forming surface 300a; ... and a mode in which the non-element forming surface 300b is back-ground (s202), and finally the wafer processing tape of this embodiment is attached to the non-element forming surface 300b (s203), and the back-grinding tape is peeled off from the element forming surface 300a; and a mode in which the back-grinding tape is attached to the element forming surface 300a, the non-element forming surface 300b is back-ground (s202), and then a modified portion is formed by laser dicing (s201), and finally the wafer processing tape of this embodiment is attached to the non-element forming surface 300b (s203), and the back-grinding tape is peeled off from the element forming surface 300a.

[0140] When peeling the backgrinding tape from the element forming surface 300a, it is preferable to peel it off while heating it, and more preferable to peel it off while heating it from the wafer processing tape side of this embodiment. The heating temperature is preferably 40°C to 80°C.

[0141] In addition, examples of using the wafer processing tape of this embodiment as a dicing tape include: a backgrinding tape is attached to the element forming surface 300a, and the non-element forming surface 300b of the wafer is backgrinded (s202), and then the wafer processing tape of this embodiment is attached to the element forming surface 300a or the non-element forming surface 300b (s203), and finally a modified portion is formed by laser dicing (s201); a wafer processing tape of this embodiment is attached to the element forming surface 300a (s203), and then a modified portion is formed by laser dicing (s201), and finally the non-element forming surface 300b is backgrinded (s202); and a wafer processing tape of this embodiment is attached to the element forming surface 300a (s203), and then the non-element forming surface 300b is backgrinded (s202), and finally a modified portion is formed by laser dicing (s201).

[0142] In the embodiment in which the tape is used as a transfer tape and the embodiment in which the tape is used as a dicing tape, an expanding step or the like may be further carried out thereafter, as will be described later.

[0143] Among these, it is preferable to perform the steps in the order of s202, s203 and s201, or s201, s202 and s203.

[0144] Furthermore, if the back grinding step s202 is not performed, steps s201 and s203 may be performed in that order, or steps s203 and s201 may be performed in that order.

[0145] 2 to 4, when steps s201, s202, and s203 are performed in this order, the backgrinding tape 200 may be attached to the element-forming surface 300a of the wafer 300, and the laser dicing step s201 in which a laser is irradiated from the non-element-forming surface 300b side of the wafer 300 and the backgrinding step s202 may be performed consecutively, and then the adhesive layer 102 of the wafer processing tape 100 may be attached to the non-element-forming surface 300b of the wafer 300 (attaching step s203), and the backgrinding tape 200 may be peeled off. Alternatively, the backgrinding tape 200 may be peeled off first, and then the wafer processing tape 100 may be attached.

[0146] Alternatively, after performing the laser dicing step s201 of irradiating the element forming surface 300a of the wafer 300 with a laser, the backgrinding step s202 may be performed by laminating the backgrinding tape 200 to the element forming surface 300a of the wafer 300, and then the adhesive layer 102 of the wafer processing tape 100 may be laminated to the non-element forming surface 300b of the wafer 300 (laminating step s203), followed by peeling off the backgrinding tape 200. Note that the backgrinding tape 200 may be peeled off first, and then the wafer processing tape 100 may be laminated.

[0147] 5 to 7, when steps s202, s203, and s201 are performed in this order, the backgrinding step s202 may be performed by attaching the backgrinding tape 200 to the element-forming surface 300a of the wafer 300, and then the adhesive layer 102 of the wafer processing tape 100 may be attached to the non-element-forming surface 300b of the wafer 300 (attaching step s203), the backgrinding tape may be peeled off, and the laser dicing step s201 may be performed by irradiating the laser from the element-forming surface 300a side of the wafer. Note that in the attaching step s203, the backgrinding tape 200 may be peeled off first, and then the wafer processing tape 100 may be attached.

[0148] Alternatively, a backgrinding tape 200 may be attached to the element forming surface 300a of the wafer 300, a backgrinding process s202 may be performed, the backgrinding tape 200 may be peeled off, and then the adhesive layer 102 of the wafer processing tape 100 may be attached to the element forming surface 300a of the wafer 300 (attaching process s203), and then a laser dicing process s201 may be performed in which a laser is irradiated from the non-element forming surface 300b side of the wafer.

[0149] 3.4.Expanding process FIG. 8(a) shows an example of a perspective view of the expanding step, and FIG. 8(b) shows an example of a cross-sectional view taken along line AA' in FIG. 8(a).

[0150] In the expanding step s204, the expanding stage 402 is pushed up from the exposed surface 100b side of the wafer processing tape 100 under conditions of about room temperature (e.g., 23°C). At this time, tension is applied to the wafer processing tape 100 between the ring frame 401 and the wafer 300, causing the wafer processing tape 100 to expand in the planar direction. Then, stress is applied outward from the center of the wafer 300, and the wafer 300 bonded to the wafer processing tape 100 is divided at the modified portions 302, etc., to form individual die chips 303.

[0151] In this embodiment, the exposed surface 100b of the wafer processing tape 100 refers to the surface of the wafer processing tape 100 that is exposed because it is not in contact with the wafer 300. Specifically, for example, it refers to the surface of the base layer 101 that is not in contact with the adhesive layer 102, or, if the wafer processing tape 100 has an antistatic layer 104, the surface of the antistatic layer 104 that is not in contact with the base layer 101.

[0152] If a wafer processing tape with weak adhesive strength to the expand stage 402 is used, there is a risk that the wafer processing tape will peel off when the expand stage 402 is pushed up a large amount. Therefore, when such a wafer processing tape is used, the expand stage 402 cannot be pushed up a large amount, and the wafer 300 tends to be insufficiently divided. In this regard, the adhesive layer 102 of the wafer processing tape 100 of this embodiment has a shear adhesive strength within an appropriate range at room temperature with respect to SUS304, a typical material of the frame 401. Therefore, even if the expand stage 402 is pushed up a large amount, the wafer processing tape 100 does not peel off from the frame 401. As a result, by pushing up the expand stage 402 a large amount, the wafer 300 is sufficiently divided, and the wafer 300 tends to be excellent in divisibility.

[0153] The expanding step s204 aims to divide the wafer 300 to obtain die chips 303, and is preferably carried out at a temperature of, for example, 20 to 40°C.

[0154] 3.5.Heat shrink process Fig. 9(a) shows an example of a perspective view of the heat shrinking step, and Fig. 9(b) shows an example of a cross-sectional view taken along line A-A' in Fig. 9(a). The wafer processing method of this embodiment preferably further includes a heat shrinking step s204 after the expanding step s204, in which a portion of the wafer processing tape 100 that is not in contact with the wafer 300 is heated to shrink the base layer 101 in the heated portion.

[0155] More specifically, a restoring force is generated in the wafer processing tape 100 stretched in the expanding step s204, so when the expanding stage 402 is lowered to reduce the tension, the die chip 303 also moves toward the center of the wafer processing tape 100 in response to the restoring force. Therefore, by performing the heat shrinking step s204 in the area where tension (restoring force) is applied between the ring frame 401 and the wafer 300, a constant tension is applied to the die chip 303 even after the expanding stage 402 is lowered.

[0156] The heat shrinking step s204 may be performed under the condition where the most tension is applied in the expanding step. In the heat shrinking step s204, it is preferable that not only the base layer 101 but also the adhesive layer 102 shrink, and it is preferable that the wafer processing tape 100 shrinks.

[0157] 9(a) and (b) illustrate the heat shrink process s204 performed when the wafer processing tape 100 is present on the expand stage 402, but the heat shrink process s204 may also be performed when the wafer processing tape 100 is present on any base other than the expand stage 402.

[0158] 3.6.Irradiation process Fig. 10(a) shows an example of a perspective view of the irradiation step, and Fig. 10(b) shows an example of a cross-sectional view taken along line A-A' in Fig. 10(a). The wafer processing method of this embodiment preferably further includes an irradiation step s206 of irradiating the adhesive layer 102 with ultraviolet light after the expanding step s204.

[0159] In the irradiation step s206, the adhesive layer 102 is irradiated with ultraviolet light to harden the adhesive layer 102 and reduce its adhesive strength to the wafer 300, thereby making it easier to pick up the die chip 303 from the wafer processing tape 100.

[0160] The ultraviolet light may be applied from the element forming surface 300a side of the wafer 300, or from the non-element forming surface 300b side of the wafer 300. The ultraviolet light may be applied from the surface of the wafer 300 that is not in contact with the wafer processing tape 100, or from the surface of the wafer 300 that is in contact with the wafer processing tape 100.

[0161] When ultraviolet light is irradiated from the side of the wafer 300 that is not in contact with the wafer processing tape 100, the wafer processing tape 100 may or may not be placed on any base.

[0162] When manually irradiating with ultraviolet light, known ultraviolet light sources such as a mercury lamp and an excimer lamp can be used as the ultraviolet light source.

[0163] 3.7.Pickup process Fig. 11(a) shows an example of a perspective view of the pick-up step, and Fig. 11(b) shows an example of a cross-sectional view taken along line A-A' in Fig. 11(a). The wafer processing method of this embodiment includes a pick-up step s207 of picking up the die chip 303 from the wafer processing tape 100.

[0164] In the pick-up step s207, although not particularly limited, for example, as shown in FIG. 10, the die tip 303 can be pushed up by a push-up needle N and the die tip 303 can be picked up by suction with a suction collet C.

[0165] The order in which the steps s204 to s207 are performed is not particularly limited as long as they are performed after the steps s201 to s203 have been completed. Below, an example of the wafer processing method of this embodiment in which the order in which the steps s204 to s207 are performed is given. [Table 1]

[0166] Among these, it is preferable to perform steps s204, s205, s206, and s207 in this order.

[0167] The wafer processing method of this embodiment may include other steps in addition to the steps described above, as necessary. While the above illustrates the laminate fabrication step of fabricating the laminate 500 by bonding the adhesive layer 102 of the wafer processing tape 100 to the surface of the wafer 300 in which the modified region 302 has been formed by laser dicing, other aspects of the laminate fabrication step may include a laminate fabrication step of fabricating the laminate 500 by bonding the adhesive layer 102 of the wafer processing tape 100 to the surface of the wafer 300 in which division grooves have been formed by laser ablation, or a laminate fabrication step of fabricating the laminate 500 by bonding the adhesive layer 102 of the wafer processing tape 100 to the surface of the wafer 300 in which division grooves have been formed by blade dicing.

[0168] Although the wafer processing method has been exemplified above, the wafer processing tape 100 of this embodiment may be used to process an adherend such as a semiconductor package instead of a wafer. [Example]

[0169] The present invention will be described in more detail below using examples and comparative examples. The present invention is not limited to the following examples. Unless otherwise specified, the experiments were carried out at 25°C and 1 atmosphere.

[0170] Example 1 An ionomer resin (manufactured by Mitsui-Dow Polychemicals, product name "Himilan 1855") was molded into an 80 μm thick sheet to obtain a substrate layer A. Next, 100 parts by mass of the antistatic agent 1SX-1055F (a quaternary ammonium salt-type acrylic polymer, product name, manufactured by Taisei Fine Chemical Co., Ltd.) and 5 parts by mass of the friction reducer KP-611 (a silicone-based graft copolymer, product name, manufactured by Shin-Etsu Chemical Co., Ltd.) were mixed to obtain a mixture for an antistatic layer. The mixture for an antistatic layer was then applied to one side of the substrate layer A to form an antistatic layer with a thickness of 0.5 μm. In each example and comparative example, when an antistatic layer was provided, the same components as in Example 1 were used for the antistatic layer.

[0171] Next, a block polymer having blocks of 53.5 mol % methacrylic acid, 40 mol % 2-ethylhexyl acrylate, 6 mol % acrylic acid, and 0.5 mol % 2-hydroxyethyl acrylate, in this order, was obtained as base polymer A. The molecular weight of the obtained base polymer was 200,000, and the glass transition temperature was -26°C.

[0172] In addition, 1 mol of isophorone diisocyanate trimer (IPDI Trimer) was reacted with the hydroxyl groups of 3 mol of dipentaerythritol pentaacrylate (DPEPA) to obtain an adduct of DPEPA and IPDI Trimer. Subsequently, 79 mol% of the adduct of DPEPA and IPDI Trimer was copolymerized with 21 mol% of dipentaerythritol hexaacrylate (DPEHA) to obtain oligomer A with an acrylic equivalent weight of 145 g / eq and a weight-average molecular weight of 100,000.

[0173] One mole of isophorone diisocyanate (IPDI) was reacted with the hydroxyl groups of one mole of 2-hydroxyethyl acrylate to obtain an adduct of 2-hydroxyethyl acrylate and IPDI. Subsequently, 44 mol% of polyethylene adipate (both ethyl acrylate termini), 36 mol% of poly(1,4-butylene adipate) (both ethyl acrylate termini), and 20 mol% of the adduct of 2-hydroxyethyl acrylate and IPDI were copolymerized to obtain oligomer B with an acrylic equivalent weight of 1345 g / eq and a weight-average molecular weight of 7930.

[0174] Then, 100 parts by mass of the base polymer A obtained as described above, 80 parts by mass of oligomer A, 80 parts by mass of oligomer B, 15 parts by mass of trimethylolpropane-adducted tolylene diisocyanate (manufactured by Mitsui Chemicals, Inc.) as a curing agent, and 3.2 parts by mass of benzyl dimethyl ketal (BDK, "IRGACURE651" manufactured by BASF) were mixed to prepare a composition for adhesive layer.

[0175] At this time, the isocyanate groups of the curing agent react with the hydroxyl or carboxyl groups of the base polymer A, crosslinking the base polymers A together. The isocyanate groups of the oligomer A and oligomer B also react with the hydroxyl or carboxyl groups of the base polymer A, and the base polymer A in the crosslinked product has polymerizable functional groups derived from the oligomer A and oligomer B. In the adhesive layer of the wafer processing tape, all of the isocyanate groups had disappeared, indicating that the reaction involving the isocyanate groups had progressed.

[0176] Finally, a composition for adhesive layer was applied to the surface of the base layer A opposite to the antistatic layer to form an adhesive layer with a thickness of 10 μm, thereby obtaining the wafer processing tape of Example 1.

[0177] Example 2 A tape for wafer processing of Example 2 was obtained in the same manner as in Example 1, except that an adhesive layer with a thickness of 5 μm was formed.

[0178] Example 3 A tape for wafer processing of Example 3 was obtained in the same manner as in Example 1, except that the amount of oligomer A used was 120 parts by mass and the amount of oligomer B used was 40 parts by mass.

[0179] Example 4 A tape for wafer processing of Example 4 was obtained in the same manner as in Example 1, except that the amount of oligomer A used was 105 parts by mass and the amount of oligomer B used was 55 parts by mass.

[0180] Example 5 One mole of hexamethylene diisocyanate (HDI) was reacted with the hydroxyl groups of one mole of dipentaerythritol pentaacrylate (DPEPA) to obtain an adduct of DPEPA and HDI. Subsequently, 81.2 mol% of the adduct of DPEPA and HDI was copolymerized with 18.8 mol% of dipentaerythritol hexaacrylate (DPEHA) to obtain oligomer C with an acrylic equivalent weight of 104.2 g / eq and a weight-average molecular weight of 4900.

[0181] Then, 100 parts by mass of the base polymer A obtained as described above, 30 parts by mass of oligomer A, 80 parts by mass of oligomer B, 50 parts by mass of oligomer C, 15 parts by mass of trimethylolpropane-adducted tolylene diisocyanate (manufactured by Mitsui Chemicals, Inc.) as a curing agent, and 3.2 parts by mass of benzyl dimethyl ketal (BDK, "IRGACURE651" manufactured by BASF) were mixed to prepare a composition for adhesive layer.

[0182] Finally, a composition for adhesive layer was applied to the surface of the base layer A opposite to the antistatic layer to form an adhesive layer with a thickness of 10 μm, thereby obtaining a wafer processing tape of Example 5.

[0183] Comparative Example 1 An ionomer resin (manufactured by Mitsui-Dow Polychemicals, product name "Himilan 1650") was molded into a sheet with a thickness of 90 μm, to obtain a substrate layer B.

[0184] Butyl acrylate, ethyl acrylate, and methoxyethyl acrylate were copolymerized to obtain base polymer B. The molecular weight of the obtained base polymer B was 2,000,000, and the glass transition temperature was -34°C.

[0185] Then, 100 parts by mass of the base polymer B obtained as described above, 60 parts by mass of oligomer B, 40 parts by mass of oligomer C, 5.25 parts by mass of trimethylolpropane-adducted tolylene diisocyanate (manufactured by Mitsui Chemicals, Inc.) as a curing agent, and 5.25 parts by mass of benzyl dimethyl ketal (BDK, "IRGACURE651" manufactured by BASF) were mixed to prepare a composition for adhesive layer.

[0186] Finally, a composition for an adhesive layer was applied to one surface of the base layer B to form an adhesive layer with a thickness of 10 μm, thereby obtaining a tape for wafer processing of Comparative Example 1.

[0187] Comparative Example 2 An ionomer resin (manufactured by Mitsui Dow Polychemicals, product name "Himilan 1650") was molded into a sheet with a thickness of 90 μm to obtain a substrate layer B. Next, 100 parts by mass of an antistatic agent and 5 parts by mass of a friction reducer were mixed to obtain a mixture for an antistatic layer. The antistatic mixture was then applied to one side of the substrate layer B to form an antistatic layer with a thickness of 0.5 μm.

[0188] A wafer processing tape for Comparative Example 2 was obtained in the same manner as Comparative Example 1, except that an adhesive layer composition was applied to the surface of the substrate layer B opposite the antistatic layer to form an adhesive layer with a thickness of 10 μm.

[0189] Comparative Example 3 An ionomer resin (manufactured by Mitsui Dow Polychemicals, product name "Himilan 1855") was molded into a sheet with a thickness of 80 μm to obtain a substrate layer A. Next, 100 parts by mass of an antistatic agent and 5 parts by mass of a friction reducer were mixed to obtain a mixture for an antistatic layer. The antistatic mixture was then applied to one side of the substrate layer A to form an antistatic layer with a thickness of 0.5 μm.

[0190] The wafer processing tape of Comparative Example 2 was obtained in the same manner as Comparative Example 1, except that an adhesive layer composition was applied to the side of the base layer A opposite the antistatic layer to form an adhesive layer with a thickness of 10 μm.

[0191] Comparative Example 4 A tape for wafer processing of Comparative Example 4 was obtained in the same manner as in Example 1, except that base polymer B was used instead of base polymer A.

[0192] Comparative Example 5 An ionomer resin (manufactured by Mitsui-Dow Polychemicals, product name "Himilan 1855") was molded into a sheet with a thickness of 80 μm, to obtain a substrate layer A.

[0193] A composition for adhesive layer was prepared by mixing 100 parts by mass of base polymer B, 80 parts by mass of oligomer B, 20 parts by mass of oligomer C, 5.25 parts by mass of trimethylolpropane-adducted tolylene diisocyanate (manufactured by Mitsui Chemicals, Inc.) as a curing agent, and 5.25 parts by mass of benzyl dimethyl ketal (BDK, "IRGACURE651" manufactured by BASF).

[0194] Finally, a composition for an adhesive layer was applied to one surface of the base layer A to form an adhesive layer with a thickness of 10 μm, thereby obtaining a tape for wafer processing of Comparative Example 5.

[0195] Comparative Example 6 A tape for wafer processing of Comparative Example 6 was obtained in the same manner as in Comparative Example 5, except that base layer B was used instead of base layer A.

[0196] Comparative Example 7 As Comparative Example 7, a wafer processing tape (manufactured by Lintec, product number: D-181) having an adhesive layer on the substrate was used. The physical properties of the adhesive layer, etc. were measured in the same manner as in other examples. Furthermore, since the composition of the adhesive layer was unknown, the composition of the adhesive layer in Table 3 was left blank.

[0197] Comparative Example 8 As Comparative Example 8, a wafer processing tape (manufactured by Nitto Denko, product number: DU-300) having an adhesive layer on the substrate was used. The physical properties of the adhesive layer, etc. were measured in the same manner as in other Examples. Furthermore, since the composition of the adhesive layer was unknown, the composition of the adhesive layer in Table 3 was left blank.

[0198] [Holding power] The wafer processing tape of each example was attached to SUS304 so that the adhesive area was 20 x 25 mm. According to JIS Z0237, the SUS304 and the wafer processing tape of each example were pressure-bonded together, and then the tape was placed vertically in an oven at 40°C. The wafer processing tape of each example, pressure-bonded to the SUS304, was placed vertically in the oven at 40°C and left for 20 minutes, after which a 1000 g weight was placed on it and the time until the weight fell was measured.

[0199] [Shear storage modulus] The shear storage modulus of the adhesive layer was measured in accordance with the storage modulus in tension mode described in JIS K7244-1:1998. Specifically, an adhesive layer was first laminated to a thickness of 0.7 mm and then placed in a thermo-hygrostat at 23°C (±2°C) and 50% relative humidity (±5%) for 40 hours. The resulting adhesive layer was used as a sample and subjected to dynamic viscoelasticity measurements in normal air. An "MSC301" dynamic viscoelasticity measuring device (manufactured by Anton Paar Japan) was used. The shear storage modulus at 25°C was obtained from the measurement results. (Measurement conditions) Measurement device: MSC301 (manufactured by Anton Paar Japan) Sample: Cylinder with a diameter of 8 mm and a thickness of 0.018 cm Pretreatment: Keep in an atmosphere at a temperature of 23°C and a relative humidity of 50% for 40 hours Test mode: Shear Frequency: 1Hz Temperature range: 0℃~30℃ Heating rate: 2℃ / min Strain range: 0.05% Load: 0N Measurement interval: 1Point / ℃

[0200] [Shear stress (shear adhesive strength)] Each wafer processing tape was attached to SUS304 so that the adhesive area was 10 x 10 mm. It was pressed in accordance with JIS Z0237 and then left to stand for 20 minutes in a room at 23°C and 50% relative humidity. It was pulled in the shear direction at a pulling rate of 300 mm / min, and the load was measured.

[0201] 〔evaluation〕 (split ratio) Using an expanding device, one wafer attached to the wafer processing tape of each example was expanded at 25°C and divided into die chips. The ratio of the number of die chips that could actually be obtained to the ideal number of die chips that could be obtained from one wafer (division rate (%): number of die chips that could actually be obtained / ideal number of die chips) was calculated. Note that die chips that were not ideally shaped, such as those with chipped corners, were not included in the number of die chips that could actually be obtained.

[0202] The division ratio when the die chip was divided into 0.6 x 0.6 mm chips is shown in the column for 0.6 x 0.6 mm chips, and the division ratio when the die chip was divided into 0.25 x 0.25 mm chips is shown in the column for 0.25 x 0.25 mm chips.

[0203] (Division accuracy) Using an expanding device, one wafer attached to the wafer processing tape of each example was expanded at 25°C and divided into die chips. Of the resulting die chips, the percentage of rectangular die chips, which are ideally shaped and free of chips, burrs, and meandering, was calculated. The division accuracy (%) when the die chips were divided into 0.6 x 0.6 mm pieces is shown in the 0.6 x 0.6 mm chip column, and the division accuracy (%) when the die chips were divided into 0.25 x 0.25 mm pieces is shown in the 0.25 x 0.25 mm chip column.

[0204] (Maximum expansion amount) Using an expanding device, the wafer processing tape of each example was attached to a frame and the expanding stage was gradually pushed up. The pushing-up was stopped when the wafer processing tape of each example broke, peeled off from the frame, or shifted from the frame. The maximum expansion amount was the amount of expansion just before the wafer processing tape of each example broke, peeled off from the frame, or shifted from the frame. The height of the expanding stage at the start of the pushing-up was set to 0, and the height to which the expanding stage was pushed up was defined as the expansion amount.

[0205] (kerf width) Using an expanding device, one wafer attached to the wafer processing tape of each example was expanded at 25°C and divided into die chips. After division, the kerf width (μm), which is the distance between the die chips, was measured and the average value was calculated.

[0206] The spacing between die chips when the die chips are divided into 0.6 x 0.6 mm pieces is shown in the 0.6 x 0.6 mm chip column, and the spacing between die chips when the die chips are divided into 0.25 x 0.25 mm pieces is shown in the 0.25 x 0.25 mm chip column.

[0207] [Table 2]

[0208] [Table 3]

[0209] In addition, after evaluating the division ratio using the wafer processing tapes obtained in Examples 1 to 5, the adhesive layer was irradiated with ultraviolet light to promote a crosslinking reaction within the adhesive layer. After that, when the die tip was picked up, the components of the adhesive layer did not adhere to the die tip, and pickup could be performed with good pickup efficiency. [Explanation of symbols]

[0210] 100...wafer processing tape, 100b...exposed surface, 101...base material layer, 101a...surface, 101b...back surface, 102...adhesive layer, 103...release liner layer, 104...antistatic layer, 200...backgrinding tape, 300...wafer, 300a...element forming surface, 300b...non-element forming surface, 301...element, 302...modifying section, 303...die tip, 400...expanding device, 401...frame, 402...expanding stage, H...heat source, L...laser source, U...ultraviolet source, C...suction collet, N...push-up needle, P...polishing machine

Claims

1. a substrate layer having a front surface and a back surface; an adhesive layer laminated on the surface of the base material layer, the holding power of the adhesive layer against SUS304 under a load of 1000 g at 40°C is 10 to 130 hours; The storage modulus of the adhesive layer at 25°C is 1.0 x 10 5 ~1.0 x 10 6 Pa, Tape for wafer processing.

2. The shear adhesive strength of the adhesive layer to SUS304 at 25°C is 1100 to 2000 MPa. The wafer processing tape according to claim 1 .

3. The substrate layer has an antistatic agent or an antistatic layer on the back surface side. The wafer processing tape according to claim 1 .

4. a bonding step of bonding the adhesive layer of the wafer processing tape according to any one of claims 1 to 3 to the surface of the wafer; a laser dicing step of laser dicing the wafer bonded to the wafer processing tape to generate cracks inside the wafer; an expanding step of expanding the wafer by pushing up an expanding stage from the exposed surface side of the wafer processing tape to form the wafer into a die chip; a pick-up step of picking up the die chip from the wafer processing tape. Wafer processing method.

5. After the expanding step, the method further includes an irradiation step of irradiating the adhesive layer with ultraviolet light. The wafer processing method according to claim 4.

6. the surface of the wafer is a non-device-forming surface; The wafer processing method according to claim 4.

7. the surface of the wafer is an element formation surface; The wafer processing method according to claim 4.

8. a laser dicing process for generating a modified portion inside the wafer by laser dicing; a back-grinding step of grinding a non-element-formed surface of the wafer; a bonding step of bonding an adhesive layer of the wafer processing tape according to any one of claims 1 to 3 to the non-device-formed surface of the wafer; an expanding step of expanding the wafer by pushing up an expanding stage from the exposed surface side of the wafer processing tape to form the wafer into a die chip; a pick-up step of picking up the die chip from the wafer processing tape. Wafer processing method.

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