TWI814982B - Adhesive sheet for workpiece processing and manufacturing method thereof - Google Patents

Abstract

An adhesive sheet for workpiece processing, comprising: a base material; and an adhesive layer laminated on one side of the base material; the adhesive layer is made of an acrylic polymer containing an active energy ray curable group introduced into a side chain It is composed of an active energy ray-curable adhesive formed from an adhesive composition, and the glass transition temperature (Tg) of the above-mentioned acrylic polymer is -80°C or more and -30°C or less, between the above-mentioned base material and the above-mentioned An adhesive sheet for workpiece processing in which a coating layer containing a pyrrolidone compound is formed on the surface in contact with the adhesive layer. Depending on the adhesive sheet for workpiece processing, residual glue on the workpiece can be suppressed.

Description

Adhesive sheet for workpiece processing and manufacturing method thereof

The present invention relates to an adhesive sheet for workpiece processing that can be suitably used for workpiece processing such as semiconductor wafers and a method for manufacturing the same.

Semiconductor wafers and various packages of silicon, gallium arsenide, etc. are manufactured in a large-diameter state, cut (dicing, also called cutting) into component slices (semiconductor wafers), and then peeled (pickup, also called wafer picking) Then, transfer to the mount step as the next step. At this time, the work (also called workpiece) such as the semiconductor wafer is in a state of being attached to the adhesive sheet for workpiece processing that has a base material and an adhesive layer, and is subjected to back grinding, cutting, cleaning, Processing such as drying, expanding, crystal picking, mounting, etc.

Here, in the above-described dicing step, defects (chipping, chipping) may occur on the cut surface of the wafer due to insufficient fixation of the object to be cut. Such missing corners will reduce the bending strength of the chip itself, causing air to be sucked into the package of the sealed IC, which may easily lead to package rupture. In recent years, thinning of semiconductor wafers has continued, and the thinner the thickness, the higher the possibility of occurrence of chipping as described above.

In order to prevent the occurrence of chipping as mentioned above, it is conceivable to increase the adhesive force. For example, Patent Document 1 proposes a dicing adhesive sheet that has an adhesive force of 10 N/min when the dicing adhesive sheet is attached to a silicon mirror wafer and then peeled off at 180° at 23°C (pulling speed 300 mm/min). Attachment temperature above 25mm. [Prior technical literature] [Patent Document]

Patent Document 1: Japanese Patent Application Publication No. 2003-142433

[Problem to be solved by the invention]

However, when using an adhesive sheet for workpiece processing with a strong adhesive force, when it is separated from the workpiece (for example, when picking up a wafer), the adhesive constituting the adhesive layer adheres to the workpiece, so-called residual glue is likely to occur. This problem of residual glue is particularly likely to occur when the workpiece has tiny recesses on the surface.

Specifically, the surface on the adhesive layer side of the workpiece processing adhesive sheet is attached to the surface of the workpiece with the concave portion, and after predetermined processing is performed on the workpiece on the workpiece processing adhesive sheet, the workpiece processing adhesive sheet is attached to the workpiece. separation. During this separation, there is a problem that the adhesive constituting the adhesive layer of the workpiece processing adhesive sheet easily adheres to the surface of the workpiece on which the adhesive sheet for workpiece processing is attached.

The present invention was made in view of such circumstances, and its object is to provide an adhesive sheet for workpiece processing that can suppress adhesive residue on the workpiece, and a method for manufacturing the same. [Methods to solve problems]

In order to achieve the above object, first, the present invention provides an adhesive sheet for workpiece processing, which includes: a base material; and an adhesive layer laminated on one side of the base material. The adhesive layer is composed of a side chain introduced with An active energy ray-curable adhesive composed of an adhesive composition of an acrylic polymer with an active energy ray-curable group. The glass transition temperature (Tg) of the acrylic polymer is -80°C or above, -30 °C or lower, an adhesive sheet for workpiece processing in which a coating layer containing a pyrrolidone compound is formed on the surface of the base material that is in contact with the adhesive layer (Invention 1).

The adhesive sheet for workpiece processing according to the above invention (Invention 1) has an active energy ray curable adhesive layer formed of an adhesive composition containing an acrylic polymer having an active energy ray curable group introduced into the side chain. It is composed of a flexible adhesive, and the glass transition temperature (Tg) of the acrylic polymer is in the above range. In addition, a coating layer containing a pyrrolidone compound is formed on the surface of the substrate in contact with the adhesive layer, which can reduce The problem of residual glue.

In the above invention (Invention 1), the acrylic polymer has a structure derived from an alkyl (meth)acrylate in the main chain of the polymer, and the acrylic group in the alkyl (meth)acrylate The number of carbon atoms is preferably 1 to 4 (Invention 2).

In the above inventions (Inventions 1 and 2), the acrylic polymer has a structure in which the main chain of the polymer is derived from a monomer containing a functional group, so that in the entire acrylic polymer, the acrylic polymer is derived from a functional group-containing monomer. The proportion of the monomer structural part is preferably 0.1% by mass or more and 12% by mass or less (Invention 3).

In the above-mentioned inventions (Inventions 1 to 3), it is preferable that the pyrrolidone-based compound is a polymer having vinylpyrrolidone as its main structural unit (Invention 4).

In the above inventions (Inventions 1 to 4), it is preferable that the storage modulus of the base material at 25°C is 1000 MPa or more (Invention 5).

In the above invention (Invention 5), it is preferable that the base material is a polyethylene terephthalate film as the base material body (Invention 6).

Among the above-mentioned inventions (Inventions 1 to 6), cutting sheets are preferred (Invention 7).

Secondly, the present invention provides a method for manufacturing an adhesive sheet for workpiece processing, which is the manufacturing method of the above-mentioned adhesive sheet for workpiece processing (Inventions 1 to 7), and includes: forming a pyrrolidone-based compound on one side of the base material body. coating layer to obtain the above-mentioned base material; coating the above-mentioned adhesive composition on the peeling surface of the release sheet to form the above-mentioned adhesive layer; that is, the surface on the coating layer side of the above-mentioned base material and The above-mentioned step of laminating the adhesive layer (Invention 8).

Thirdly, the present invention provides a method for manufacturing an adhesive sheet for workpiece processing, which is the manufacturing method of the above-mentioned adhesive sheet for workpiece processing (Invention 3). A (meth)acrylate copolymer that is copolymerized in an amount of An acrylic polymer with an active energy ray-curable group and a step of preparing an adhesive composition containing the acrylic polymer; forming a coating layer containing a pyrrolidone compound on one side of the base material body to obtain the above base material Steps; the step of coating the above-mentioned adhesive composition on the peeling surface of the release sheet to form the above-mentioned adhesive layer; and the step of laminating the surface of the coating layer side of the above-mentioned base material with the above-mentioned adhesive layer (invention 9).

In the above invention (Invention 9), the amount of the active energy ray-curable group-containing compound having the above-mentioned functional group is 60 mol% or more, 99 mol%, relative to the amount of the functional group of the functional group-containing monomer. % or less is preferred (Invention 10). [Effects of the invention]

The adhesive sheet for workpiece processing related to the present invention can suppress adhesive residue on the workpiece. Furthermore, according to the manufacturing method of an adhesive sheet for workpiece processing related to the present invention, it is possible to efficiently manufacture an adhesive sheet for workpiece processing that can suppress adhesive residue on the workpiece.

Hereinafter, embodiments of the present invention will be described. An adhesive sheet for workpiece processing according to an embodiment of the present invention includes a base material and an adhesive layer laminated on one side of the base material. The adhesive layer is composed of an active energy ray curable adhesive composed of an adhesive composition containing an acrylic polymer having an active energy ray curable group introduced into the side chain. The glass transition of the acrylic polymer is Temperature (Tg) is above -80°C and below -30°C. In addition, a coating layer containing a pyrrolidone compound is formed on the surface of the base material that is in contact with the adhesive layer.

When using the adhesive sheet for workpiece processing according to this embodiment, the workpiece is attached to the surface opposite to the base material (hereinafter, sometimes referred to as the "adhesive surface") of the adhesive layer of the adhesive sheet for workpiece processing, and the workpiece is Predetermined processing is performed on the workpiece on the processing adhesive sheet. Next, the adhesive layer is irradiated with energy rays to harden the adhesive layer, and then the adhesive sheet for workpiece processing is separated from the workpiece. By having the above-mentioned structure, the adhesive sheet for workpiece processing according to this embodiment can effectively suppress adhesive residue on the workpiece when it is separated from the workpiece. In particular, when the adhesive layer is composed of an active energy ray-curable adhesive composed of an adhesive composition containing an acrylic polymer having an active energy ray-curable group introduced into the side chain, the active energy ray can be With the irradiation, the adhesion to the workpiece is easily reduced, and when separated from the workpiece, there is less adhesive residue on the side of the workpiece. In addition, when the glass transition temperature (Tg) of the adhesive is -30°C or less, the adhesion to the base material becomes high, and it becomes less likely that the adhesive will remain on the workpiece side when separated from the workpiece. Furthermore, since there is a coating layer containing a pyrrolidone compound on the surface of the base material that is in contact with the adhesive layer, the adhesion between the base material and the adhesive layer becomes higher, and when the workpiece is separated from the workpiece, the adhesion between the base material and the adhesive layer becomes higher. , it becomes less likely to have adhesive residue on the workpiece side. The related adhesive residue suppression effect can be effectively exerted even if there are tiny recesses on the surface of the workpiece that is in contact with the adhesive surface of the adhesive sheet for workpiece processing.

From the viewpoint of suppressing adhesive residue, the glass transition temperature (Tg) of the acrylic polymer must be -30°C or lower, preferably -32°C or lower, and particularly preferably -35°C or lower. In addition, from the viewpoint of similar residual glue suppression, the glass transition temperature (Tg) of the above-mentioned acrylic polymer is preferably -80°C or higher, more preferably -70°C or higher, and particularly -55°C or higher. Better. In this specification, the glass transition temperature (Tg) is a calculated value that can be obtained by Fox's equation.

On the other hand, in this embodiment, the storage modulus of the base material at 25°C is preferably 1000 MPa or more. Since the base material has a relevant storage modulus, the occurrence of wobbling of the workpiece processing adhesive sheet during cutting is reduced. As a result, the movement of the workpiece attached to the workpiece processing adhesive sheet is restricted, and the occurrence of chipping is suppressed. Generally, when the base material has a large storage modulus as described above, the adhesion between the base material and the adhesive layer decreases, and when the base material is separated from the workpiece, it becomes easy for the adhesive to remain on the workpiece side. However, this embodiment is related to By having the above-mentioned structure, the adhesive sheet for workpiece processing can suppress residual adhesive even when using a base material with a large storage modulus as mentioned above.

From the above point of view, the storage modulus of the base material at 25°C is more preferably 1200 MPa or more, especially 1500 MPa or more. On the other hand, the storage modulus of the base material at 25°C is preferably 3000 MPa or less. By setting the upper limit of the storage modulus as described above, the adhesive sheet for workpiece processing has appropriate elasticity and can be separated from the workpiece well (including picking up wafers). In addition, the method for measuring the storage modulus of the base material is as shown in the following test examples.

The specific structure of an example of the adhesive sheet for workpiece processing related to this embodiment is shown in FIG. 1 . As shown in FIG. 1 , an adhesive sheet 1 for workpiece processing according to an embodiment includes a base material 2 , an adhesive layer 3 laminated on one side of the base material 2 , and an adhesive layer 3 laminated on the adhesive layer 3 . The release sheet 4 on the opposite side of the base material 2. The base material 2 includes a base material body 21 and a coating layer 22 containing a pyrrolidone compound, and the coating layer 22 is located on the side adjacent to the adhesive layer 3 . Moreover, the release sheet 4 is provided so that the release surface of the release sheet 4 may be adjacent to the adhesive layer 3 . In addition, in this specification, the release surface of the release sheet refers to the surface of the release sheet that has releasability, and includes any of the surface that has been subjected to a release process and the surface that still shows releasability even if the release process has not been performed.

1. Components of the adhesive sheet for workpiece processing (1)Substrate The base material 2 in this embodiment includes a base material body 21 and a coating layer 22 containing a pyrrolidone compound provided on the adhesive layer 3 side of the base material body 21 .

(1-1)Substrate body The base material body 21 in this embodiment is not particularly limited as long as it can exert the desired function when using the adhesive sheet for workpiece processing. However, from the viewpoint of suppressing the occurrence of chipping during cutting, the base material 2 is preferably one that can exhibit the above-mentioned storage modulus. Furthermore, in this embodiment, since the coating layer 22 has almost no influence on the storage modulus of the base material 2, the storage modulus of the base material 2 and the storage modulus of the base material body 21 can be regarded as the same.

When the workpiece is like a semiconductor wafer and has no or relatively low penetrability to active energy rays (especially ultraviolet rays), it is preferable that the base material body 21 has good penetrability to active energy rays. By irradiating the adhesive layer 3 with active energy rays through the base material 2, the adhesive layer 3 can be cured favorably. In addition, when the workpiece is made of a material that has good penetrability to active energy rays, such as a glass member, the surface of the glass member has unevenness (for example, unevenness formed by printing), and the surface of the glass member has unevenness. When there is a possibility that active energy rays (especially ultraviolet rays) due to unevenness cannot exhibit sufficient penetrability, it is preferable that the base material body 21 has good penetrability to active energy rays.

The base body 21 is preferably a resin film whose main material is a resin-based material. Specific examples thereof include polyester-based films such as polyethylene terephthalate film, polybutylene terephthalate film, and polyethylene naphthalate; and ethylene-vinyl acetate copolymer film. ; Ethylene-based copolymer films such as ethylene-(meth)acrylate copolymer film and other ethylene-(meth)acrylate copolymer films; polyethylene film, polypropylene film, polybutylene film, polybutylene film Polyolefin-based films such as diene films, polymethylpentene films, ethylene-norbornene copolymer films, norbornene resin films; polyvinyl chloride-based films such as polyvinyl chloride films, vinyl chloride copolymer films, etc.; (Meth)acrylate copolymer film; polyurethane film; polyimide film; polystyrene film; polycarbonate film; fluororesin film, etc. Examples of polyethylene films include low-density polyethylene (LDPE) films, linear low-density polyethylene (LLDPE) films, high-density polyethylene (HDPE) films, and the like. In addition, modified membranes such as cross-linked membranes and ionic polymer membranes can also be used. In addition, the base material may be a laminated film formed by laminating a plurality of the above-mentioned films. In this laminated film, the materials constituting each layer may be the same or different. In addition, in this specification, "(meth)acrylic acid" means both acrylic acid and methacrylic acid. The same applies to other similar terms.

As the base material body 21 in this embodiment, among the above-mentioned films, polyester-based films, rigid vinyl chloride films, polystyrene films, polycarbonate films, etc. are preferred, and polyester-based films are particularly preferred. Among polyester films, polyethylene terephthalate films are particularly preferred. The above-mentioned film easily satisfies the above-mentioned storage modulus, and therefore easily suppresses the occurrence of chipping.

The base material body 21 may also contain various additives such as flame retardants, plasticizers, antistatic agents, lubricants, antioxidants, colorants, infrared absorbers, ultraviolet absorbers, and ion trapping agents. The content of the additive is not particularly limited, but it is preferably within a range in which the desired function of the base body 21 is exerted.

The thickness of the base material body 21 may be appropriately set according to the method in which the adhesive sheet 1 for workpiece processing is used. However, from the viewpoint of suppressing the occurrence of chipping, it is preferably 20 μm or more, and particularly preferably 25 μm or more. , further preferably above 40 μm. In addition, the thickness is preferably 450 μm or less, particularly preferably 300 μm or less, and further preferably 200 μm or less.

(1-2)Coating layer The coating layer 22 in this embodiment contains a pyrrolidone compound. The presence of this coating layer 22 improves the adhesion between the base material 2 and the adhesive layer 3, effectively suppressing adhesive residue when separated from the workpiece. Although the reason for this is not necessarily fully understood, it is speculated that the pyrrolidone-based compound bonds or reacts with the functional groups contained in the adhesive constituting the adhesive layer 3, especially with the hydroxyl group, so that the adhesive layer 3 can easily adhere to the coating layer. 22 reasons.

The pyrrolidone-based compound only needs to be a compound having a pyrrolidone skeleton, and may be a monomer or a polymer. Among them, from the viewpoint of adhesion to the adhesive layer 3 of the coating layer 22, a polymer having a pyrrolidone skeleton is preferred, and in particular, a polymer containing vinylpyrrolidone as a main structural unit is preferred. The polymer may be a homopolymer of vinylpyrrolidone (polyvinylpyrrolidone) or a copolymer of vinylpyrrolidone and other monomers. In the case of such a copolymer, the content ratio of the vinylpyrrolidone component is preferably 50% by mass or more.

Examples of other monomers include monomers having an addition polymerizable unsaturated group such as a vinyl group, a (meth)acrylyl group, and an allyl group. Related other monomers may also have an alkyl group, an alkyl ester group, an alkyl ether group, a hydroxyl group, a carboxyl group, a amide group, an amine group, a polyalkyl ether group, etc. in the side chain.

Specific examples of the other monomers include (meth)acrylic acid, (meth)alkyl methacrylates such as (meth)methyl methacrylate, and hydroxyethyl (meth)acrylate, etc. Monoester of (meth)acrylic acid and glycol, alkali metal salt of (meth)acrylic acid, ammonium salt of (meth)acrylic acid, vinyl acetate, N-vinylimidazole, N-vinyl acetamide, N - Vinylformamide, N-vinylcaprolactamide, (meth)acrylamide, N-alkyl(meth)acrylamide, N-hydroxymethyl(meth)acrylamide, etc. Ethylene monomer, etc.

The weight average molecular weight of the polymer having a pyrrolidone skeleton is preferably 50,000 or more, and particularly preferably 100,000 or more. In addition, the weight average molecular weight is preferably 1,000,000 or less, particularly 800,000 or less, and further preferably 700,000 or less. Here, the weight average molecular weight in this specification is a value measured by gel permeation chromatography (GPC) in terms of standard polystyrene.

The coating layer 2 in this embodiment is preferably formed by applying a coating agent containing a pyrrolidone compound. The related coating agent preferably contains a binder resin in addition to the pyrrolidone compound, and further preferably contains a hardener (crosslinking agent) that reacts with the binder resin.

The content of the pyrrolidone compound in the coating agent (in terms of solid content) is preferably 20 mass% or more, and particularly preferably 30 mass% or more. In addition, the content is preferably 80 mass% or less, and particularly preferably 70 mass% or less.

Preferable examples of the binder resin include polyester binder resin, acrylic binder resin, polyether-urethane binder resin, and the like. Among them, polyester-based binder resin is preferred from the viewpoint of affinity to the base material. As the polyester-based binder resin, a water-based polyester-based binder resin is preferred. The water-based polyester binder resin takes the form of an aqueous solution dissolved in water, but may also take the form of a water dispersion dispersed in water as an emulsion.

The above-mentioned water-based polyester binder resin preferably has an acid value of 10.0KOHmg/g or more and a hydroxyl value of 2.0KOHmg/g or more. This results in good adhesion to the base material body 21 . From a related perspective, the acid value of the water-based polyester binder resin is more preferably 15.0KOHmg/g or more, especially 20.0KOHmg/g or more, further preferably 30.0KOHmg/g or more, and 40.0 KOHmg/g or above is the best. In addition, the hydroxyl value of the water-based polyester-based binder resin is more preferably 2.5KOHmg/g or more, especially 3.0KOHmg/g or more, further preferably 3.5KOHmg/g or more, and 4.0KOHmg/g or more. for the best. In addition, the above-mentioned acid value and hydroxyl value are values measured based on the standards of JIS K0070-1992.

Examples of the water-based polyester-based binder resin include copolymers obtained by polycondensation of alcohol components and carboxylic acid components, modified products of the copolymers, and the like.

As the alcohol component, a polyhydric alcohol having two or more hydroxyl groups per molecule can be used. Specific alcohol components include, for example, ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, propylene glycol, dipropylene glycol, 1,4-butanediol, and 1,3-butanediol. , 2,3-butanediol, 1,2-butanediol, 3-methyl-1,2-butanediol, 1,2-pentanediol, 1,5-pentanediol, 1,4- Pentylene glycol, 2,4-pentanediol, 3-methyl-4,5-pentanediol, 2,2,4-trimethyl-1,3-pentanediol, 1,6-hexanediol , 1,5-hexanediol, 1,4-hexanediol, 2,5-hexanediol, neopentyl glycol, hydroxypivalic acid neopentyl glycol ester, etc. Alcohols; polylactone diols in which lactones such as ε-caprolactone are added to these diols; polyester diols such as bis(hydroxyethyl) terephthalate; 1, 3-Cyclohexane dimethanol, 1,4-cyclohexanedimethanol, tricyclodecane dimethanol, hydrogenated bisphenol A, hydrogenated bisphenol F, spiroglycol, dimethylol tricyclodecane and other divalent cyclic alcohols; ethylene oxide and propylene oxide addition products of bisphenol A; glycerol, trimethylolpropane, trimethylolethane, diglycerol, triplycerol, Trivalent or higher polyhydric alcohols such as 1,2,6-hexanetriol, neopentylerythritol, dineopenterythritol, sorbitol, and mannitol. These alcohol components can be used individually or in combination of 2 or more types.

As the carboxylic acid component, a polybasic acid having two or more carboxyl groups per molecule can be used. Specific carboxylic acid components include, for example, phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, 4,4-biphenyldicarboxylic acid, and diphenylmethane-4,4'-di. Carboxylic acid, succinic acid, adipic acid, azelaic acid, Sebacic acid, chloronic acid, maleic acid, fumaric acid, itaconic acid, cyclohexane-1,3-dicarboxylic acid, cyclohexane-1,4-dicarboxylic acid, hexahydrogen Dicarboxylic acids such as phthalic acid, hexahydroisophthalic acid, hexahydroterephthalic acid, methylhexahydrophthalic acid and their anhydrides; trimellitic acid, trimesic acid , methylcyclohexanetricarboxylic acid, hexahydrotrimellitic acid, tetrachlorohexanetricarboxylic acid and other tricarboxylic acids and their anhydrides; 1,2,4,5-cyclohexanetetracarboxylic acid, 1,2,3,4-butanetetracarboxylic acid, 1,2,3,4-cyclobutanetetracarboxylic acid, 1,2,3,4-cyclopentanetetracarboxylic acid, pyromellitic acid acid) and other tetracarboxylic acids and their anhydrides, etc. These carboxylic acid components can be used individually or in combination of 2 or more types.

The weight average molecular weight of the water-based polyester binder resin is preferably 1,000 to 20,000, and more preferably 1,500 to 15,000 from the viewpoint of solubility or dispersibility in water and adhesion to the base material body 21 It is better, especially 2000~10000 is better, and further 500~7500 is better.

The content of the binder resin in the coating agent (in terms of solid content) is preferably 20% by mass or more, and particularly preferably 30% by mass or more. In addition, the content is preferably 80 mass% or less, and particularly preferably 70 mass% or less.

唑啉系化合物、醯肼系化合物、異氰酸酯系化合物、烷氧矽烷系化合物、胺系化合物等。此等硬化劑可使用單獨1種，亦可組合2種以上使用。上述當中，從與水性聚酯系結合劑樹脂的反應性的觀點而言，以環氧系化合物、碳二醯亞胺系化合物或

唑啉系化合物為佳，特別是以

唑啉系化合物為佳。此外，此等化合物從與水性聚酯系結合劑樹脂的相溶性的觀點而言，以水溶性者為佳。 The hardener is not particularly limited as long as it reacts with the binder resin, but examples thereof include epoxy compounds, carbodiimide compounds,

Oxazoline compounds, hydrazine compounds, isocyanate compounds, alkoxysilane compounds, amine compounds, etc. These hardeners can be used individually by 1 type, or in combination of 2 or more types. Among the above, from the viewpoint of reactivity with aqueous polyester-based binder resin, epoxy-based compounds, carbodiimide-based compounds or

Oxazoline compounds are preferred, especially

Oxazoline compounds are preferred. In addition, from the viewpoint of compatibility with the water-based polyester-based binder resin, those compounds that are water-soluble are preferred.

The epoxy compound may be any compound having two or more epoxy groups or epoxypropyl groups in the molecule. In addition, the carbodiimide-based compound is preferably one containing at least two carbodiimide groups in the molecule.

唑啉系化合物，只要是分子中含有至少2個以上

唑啉基者即可，可列舉，例如，在2位的碳位置具有含有不飽和碳-碳鍵結的取代基的加成聚合性2-㗁唑啉(例如，2-異丙烯基-2-㗁唑啉)的均聚物、該加成聚合性2-㗁唑啉與其他不飽和單體的共聚物等。as

Zozoline compounds, as long as the molecule contains at least 2 or more

It suffices to be an oxazoline group, and examples thereof include, for example, addition polymerizable 2-oxazoline having a substituent containing an unsaturated carbon-carbon bond at the carbon position of the 2-position (for example, 2-isopropenyl-2 Homopolymer of -tetrazoline), copolymers of the addition polymerizable 2-tetrazoline and other unsaturated monomers, etc.

When the tetrazoline compound is a polymer, its weight average molecular weight is preferably 10,000 to 300,000, and more preferably 50,000 to 200,000.

The content of the hardener in the coating agent (in terms of solid content) is preferably 1% by mass or more, and particularly preferably 3% by mass or more. In addition, the content is preferably 20% by mass or less, and particularly preferably 15% by mass or less.

The lower limit of the thickness of the coating layer 22 is preferably 0.01 μm or more, and particularly preferably 0.03 μm or more, from the viewpoint of adhesion to the adhesive layer 3 . In addition, from the viewpoint of preventing obstruction, the upper limit of the thickness of the coating layer 22 is preferably 10 μm or less, particularly 1 μm or less, and further preferably 0.2 μm or less.

(2)Adhesive layer The adhesive layer 3 in this embodiment is an adhesive composition (hereinafter sometimes referred to as "adhesive composition P") containing an acrylic polymer (A) in which an active energy ray curable group is introduced into the side chain. ") formed by active energy ray curable adhesive. The adhesive composition P in this embodiment preferably contains an acrylic polymer (A) and a cross-linking agent (B), and further preferably contains a photopolymerization initiator (C).

(2-1)Each ingredient (2-1-1) Acrylic polymer (A) in which an active energy ray curable group is introduced into the side chain An acrylic polymer (A) having an active energy ray curable group introduced into the side chain, a (meth)acrylate copolymer (AP) having a functional group, and an acrylic polymer having a functional group capable of reacting with the functional group. The compound (A3) having an active energy ray curable group is preferably obtained by reaction.

The (meth)acrylate polymer (AP) is preferably a copolymer of at least an alkyl (meth)acrylate (A1) and a functional group-containing monomer (A2) having a reactive functional group. .

As the (meth)acrylic acid alkyl ester (A1), one having a carbon number of 1 to 18 in the alkyl group is preferred, and one having a carbon number of 1 to 4 is particularly preferred. When the carbon number is 1 to 4, the adhesive layer 3 obtained has higher adhesion to the base material 2 .

Specific examples of alkyl (meth)acrylate (A1) include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, and n-butyl (meth)acrylate. Ester, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, n-decyl (meth)acrylate, ( Lauryl methacrylate, myristyl (meth)acrylate, palmityl (meth)acrylate, stearyl (meth)acrylate, etc. Among these, methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate or n-butyl (meth)acrylate is preferred, especially methyl methacrylate or acrylic acid. n-butyl ester is preferred. These can be used individually or in combination of 2 or more types.

The mass ratio of the structural part derived from the alkyl (meth)acrylate (A1) in the (meth)acrylate copolymer (AP) is preferably 50 to 98 mass %, especially 60 to 95 % by mass is preferred, and 70 to 90 mass % is more preferred.

As the functional group-containing monomer (A2), one having a reactive functional group capable of reacting with the functional group of the active energy ray-curable group-containing compound (A3) can be used. Examples of the functional group possessed by the functional group-containing monomer (A2) include a hydroxyl group, a carboxyl group, an amino group, a substituted amino group, an epoxy group, and the like. Among them, a hydroxyl group or a carboxyl group is preferred, especially a hydroxyl group. Better. Furthermore, when using the cross-linking agent (B), it is preferable that all the reactive functional groups of the functional group-containing monomer (A2) react with the cross-linking agent (B).

When a monomer having a hydroxyl group (hydroxyl group-containing monomer) is used as the functional group-containing monomer (A2), examples thereof include hydroxyalkyl (meth)acrylate, and specific examples thereof include: 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, (meth)acrylic acid 3 -Hydroxybutyl ester, 4-hydroxybutyl (meth)acrylate, etc. Among these, 2-hydroxyethyl (meth)acrylate is preferred from the viewpoint of reactivity of hydroxyl groups and copolymerizability. These can be used individually or in combination of 2 or more types.

When a monomer having a carboxyl group (carboxyl group-containing monomer) is used as the functional group-containing monomer (A2), examples thereof include ethylenically unsaturated carboxylic acid, and specific examples thereof include acrylic acid, Methacrylic acid, crotonic acid, maleic acid, itaconic acid, citraconic acid, etc. Among these, acrylic acid is preferred from the viewpoint of reactivity of the carboxyl group and copolymerizability. These can be used individually or in combination of 2 or more types.

Furthermore, different types of functional group-containing monomers (A2) may be used in combination. For example, the above-mentioned hydroxyl group-containing monomer and carboxyl group-containing monomer may be used in combination.

The mass ratio of the structural part derived from the functional group-containing monomer (A2) in the (meth)acrylate polymer (AP) is preferably 5 mass % or more, particularly 7 mass % or more, Furthermore, it is preferably 10% by mass or more. In addition, the ratio is preferably 35 mass% or less, particularly 30 mass% or less, and further preferably 17 mass% or less. When the mass ratio of the structural part derived from the functional group-containing monomer (A2) is within the above range, the active energy ray-containing acrylic polymer (A) having an energy ray curable group introduced into the side chain can be cured. The introduction amount of the compound (A3) having a sexual group is within a suitable range. In addition, when the cross-linking agent (B) is used to react the functional group-containing monomer (A2) with the cross-linking agent (B), the degree of cross-linking, that is, the coagulation can be controlled by the cross-linking agent (B). When the gel fraction is in an appropriate range, physical properties such as the cohesive force of the adhesive layer 3 can be controlled. Furthermore, when the ratio is 17% by mass or less, the residual glue suppressing effect becomes better.

The (meth)acrylate copolymer (AP) may be copolymerized with other monomers together with the alkyl (meth)acrylate (A1) and the functional group-containing monomer (A2).

Examples of the other monomers include methoxymethyl (meth)acrylate, methoxyethyl (meth)acrylate, ethoxymethyl (meth)acrylate, and ethyl (meth)acrylate. Alkoxyalkyl group-containing (meth)acrylates such as oxyethyl ester; aliphatic ring-containing (meth)acrylates such as cyclohexyl (meth)acrylate; phenyl (meth)acrylate, etc. (Meth)acrylates with aromatic rings; N-(meth)acrylylmorpholine, N-vinyl-2-pyrrolidone, N-(meth)acrylylpyrrolidone, etc. with nitrogen-containing Heterocyclic monomers; non-crosslinking acrylamide such as (meth)acrylamide, N,N-dimethyl(meth)acrylamide; (meth)acrylic acid N,N-di (meth)acrylates with non-crosslinking tertiary amine groups such as methylaminoethyl ester and N,N-dimethylaminopropyl (meth)acrylate; vinyl acetate; benzene Ethylene etc. Among the above, monomers having a nitrogen-containing heterocyclic ring, non-crosslinking acrylamide or vinyl acetate are preferred, especially N-(meth)acrylmorpholine, dimethyl (meth) Acrylic acid acrylamide or vinyl acetate is preferred, and N-acrylamide or dimethylacrylamide is further preferred. By copolymerizing the relevant monomers, the resulting adhesive layer 3 has better adhesion to the base material 2 . These monomers can be used alone or in combination of two or more types.

The mass ratio of the structural part derived from the other monomers in the (meth)acrylate copolymer (AP) is preferably 1 mass % or more, particularly 3 mass % or more, and further 5 mass %. The above is better. In addition, the ratio is preferably 20 mass% or less, particularly 18 mass% or less, and further preferably 15 mass% or less. As a result, the adhesive layer 3 obtained has better adhesion to the base material 2 .

The polymerization state of the (meth)acrylate copolymer (AP) can be a random copolymer or a block copolymer. In addition, the polymerization method is not particularly limited, and polymerization can be performed by a general polymerization method, for example, a solution polymerization method.

On the other hand, the active energy ray-curable group-containing compound (A3) contains a functional group that can react with the functional group of the functional group-containing monomer (A2), and a compound that is cleaved by irradiation with active energy rays. Active energy ray hardening base of carbon-carbon double bonds.

Examples of the functional group that can react with the functional group of the functional group-containing monomer (A2) include an isocyanate group, an epoxy group, and the like. Among them, an isocyanate group having high reactivity with a hydroxyl group is preferred.

As the active energy ray curable group containing a carbon-carbon double bond, a (meth)acrylyl group or the like is preferred. Furthermore, it is preferable that there are 1 to 5 carbon-carbon double bonds broken by irradiation of active energy rays in 1 molecule of the active energy ray curable group-containing compound (A3), especially 1 to 3 One is better.

Examples of the active energy ray curable group-containing compound (A3) include 2-methacryloyloxyethyl isocyanate, m-isopropenyl-α,α-dimethylbenzyl isocyanate, and methacryloxyethyl isocyanate. Acrylyl isocyanate, allyl isocyanate, 1,1-(bisacryloxymethyl)ethyl isocyanate; obtained by reacting diisocyanate compounds or polyisocyanate compounds with hydroxyethyl (meth)acrylate Acrylyl monoisocyanate compounds; acrylyl monoisocyanate compounds obtained by reacting diisocyanate compounds or polyisocyanate compounds with polyol compounds and hydroxyethyl (meth)acrylate, etc. Among these, 2-methacryloxyethyl isocyanate is particularly preferred. In addition, the active energy ray curable group-containing compound (A3) may be used alone or in combination of two or more types.

The acrylic polymer (A) can be prepared by preparing a (meth)acrylate copolymer (AP), and the (meth)acrylate copolymer (AP) and the compound (A3) containing an active energy ray curable group. ) reaction is carried out according to general methods. In this reaction step, the reactive functional group derived from the functional group-containing monomer (A2) in the (meth)acrylate copolymer (AP) and the active energy ray curable group-containing compound (A3) Functional group reaction. In this way, an acrylic polymer (A) in which an energy-beam curable group is introduced into the side chain can be obtained. Furthermore, the reaction between the (meth)acrylate copolymer (AP) and the active energy ray curable group-containing compound (A3) is preferably carried out in the presence of a catalyst such as an organic metal catalyst.

In the acrylic polymer (A), the amount of the active energy ray-curable group-containing compound (A3) relative to the amount of the reactive functional group of the functional group-containing monomer (A2) is 60 mol %. The above is preferred, especially above 70 mol%. In addition, the amount of the active energy ray curable group-containing compound (A3) is preferably 99 mol% or less, particularly 95% or less, and further preferably 90 mol% or less.

In the entire acrylic polymer (A), the proportion of the structural part derived from the functional group-containing monomer (A2) is preferably 0.1 mass % or more, particularly 0.5 mass % or more, and further 1 mass %. The above is better. In addition, the ratio is preferably 12 mass% or less, particularly 10 mass% or less, and further preferably 8 mass% or less. In this way, the adhesive layer 3 obtained has better adhesion to the base material 2 (coating layer 21).

The weight average molecular weight (Mw) of the acrylic polymer (A) is preferably 10,000 or more. In addition, the weight average molecular weight (Mw) is preferably 1.5 million or less. When the weight average molecular weight (Mw) of the acrylic polymer (A) is within the above range, the coating properties of the adhesive composition P are ensured and the cohesiveness of the adhesive layer 3 becomes good, so that it is possible to obtain a material suitable for cutting. etc. physical properties.

Furthermore, the glass transition temperature (Tg) of the acrylic polymer (A) in which an energy-beam curable group is introduced into the side chain is as described above.

(2-1-2) Cross-linking agent (B) The adhesive composition P preferably contains a cross-linking agent (B) capable of cross-linking the acrylic polymer (A) in which an energy-beam curable group is introduced into the side chain. At this time, the adhesive layer 3 in this embodiment contains a cross-linked product obtained by cross-linking reaction between the acrylic polymer (A) and the cross-linking agent (B). By using the relevant cross-linking agent (B), it becomes easy to adjust the gel fraction of the adhesive forming the adhesive layer 3 to a suitable range, and physical properties suitable for cutting and the like can be obtained.

Examples of types of the crosslinking agent (B) include polyimine compounds such as epoxy compounds, polyisocyanate compounds, metal chelate compounds, aziridine compounds, and melamine resins. , urea resin, dialdehydes, hydroxymethyl polymer, metal alkoxide (metal alkoxide), metal salt, etc. Among these, it is preferable to use an epoxy compound or a polyisocyanate compound for reasons such as easy control of the cross-linking reaction, and particularly it is preferable to use a polyisocyanate compound.

Examples of the epoxy compound include 1,3-bis(N,N'-diepoxypropylaminomethyl)cyclohexane, N,N,N',N'-tetraepoxypropane Base-m-phenylenediamine, ethylene glycol diepoxypropyl ether, 1,6-hexanediol diepoxypropyl ether, trimethylolpropane diepoxypropyl ether, diepoxypropyl ether aniline, diepoxypropylamine, etc.

The polyisocyanate-based compound is a compound having two or more isocyanate groups per molecule. Specific examples include aromatic polyisocyanates such as tolylene diisocyanate, diphenylmethane diisocyanate, and xylylene diisocyanate; aliphatic polyisocyanates such as hexamethylene diisocyanate; and isocyanate. Alicyclic polyisocyanates such as phorone diisocyanate and hydrogenated diphenylmethane diisocyanate. Further examples include biurets, isocyanurates, and adducts thereof. Examples of the adduct include reaction products with low-molecular active hydrogen-containing compounds such as ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, and castor oil.

The cross-linking agent (B) may be used individually by 1 type, or in combination of 2 or more types.

The content of the cross-linking agent (B) in the adhesive composition P is preferably 0.01 to 15 parts by mass relative to 100 parts by mass of the acrylic polymer (A) having an energy-ray curable group introduced into the side chain. In particular, it is preferably 0.05 to 10 parts by mass, and further preferably 0.1 to 2 parts by mass.

(2-1-3) Photopolymerization initiator (C) When ultraviolet rays are used as active energy rays used to harden an active energy ray-curable adhesive, the adhesive composition P preferably further contains a photopolymerization initiator (C). By containing such a photopolymerization initiator (C), the acrylic polymer (A) having an energy ray curable group introduced into the side chain can be polymerized and cured efficiently, and the polymerization curing time and activity can be improved. The amount of energy ray exposure is reduced.

Examples of the photopolymerization initiator (C) include benzophenone, acetophenone, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isopropyl ether. Butyl ether, benzoin benzoic acid, benzoin benzoate methyl ester, benzoin dimethyl ketal, 2,4-diethyl thioxanthone, 1-hydroxycyclohexyl Phenyl ketone, benzyl diphenyl sulfide, tetramethylthiuram monosulfide, azobisisobutyronitrile, benzyl, bibenzyl, diacetyl, β-chloroanthracene Quinone, (2,4,6-trimethylbenzyldiphenyl)phosphine oxide, 2-benzothiazole-N,N-dimethyldithiocarbamate, oligo{2-hydroxy-2 -Methyl-1-[4-(1-propenyl)phenyl]acetone}, 2,2-dimethoxy-1,2-diphenylethan-1-one, 2-hydroxy-1- {4-[4-(2-hydroxy-2-methyl-propanyl)-benzyl]phenyl}-2-methyl-propan-1-one, etc. These can be used individually or in combination of 2 or more types.

The content of the photopolymerization initiator (C) in the adhesive composition P is 0.1 to 10 parts by mass relative to 100 parts by mass of the acrylic polymer (A) in which an energy ray curable group is introduced into the side chain. It is better, especially 0.5~8 parts by mass.

(2-1-4)Other ingredients In the adhesive composition P in this embodiment, as long as the above-mentioned effects related to the adhesive sheet 1 for workpiece processing related to this embodiment are not impaired, desired additives may be added, such as antistatic agents, tackifiers, antioxidants, optical Stabilizers, softeners, fillers, etc. In addition, the following dilution solvent is not included in the additives constituting the adhesive composition P.

(2-2) Preparation of adhesive composition The adhesive composition P in this embodiment can be produced by producing an acrylic polymer (A), and the obtained acrylic polymer (A) can be photopolymerized with a cross-linking agent (B) as necessary. The starting agent (C) and additives are mixed and manufactured. At this time, a diluting solvent may be added as necessary to obtain a coating liquid of the adhesive composition P.

As the dilution solvent, for example, aliphatic hydrocarbons such as hexane, butane, and cyclohexane, aromatic hydrocarbons such as toluene and xylene, halogenated hydrocarbons such as dichloromethane and dichloroethane, methanol, and ethanol can be used. , alcohols such as propanol, butanol, 1-methoxy-2-propanol, ketones such as acetone, butanone, 2-pentanone, isophorone, cyclohexanone, ethyl acetate, butyl acetate Esters such as ethyl cellulose, cellulose-based solvents such as ethyl cellulose, etc.

The concentration and viscosity of the coating liquid prepared by this method are not particularly limited as long as it is within the coating range, and can be appropriately selected according to the situation. For example, the concentration of the adhesive composition P is diluted so that it becomes 10 mass % or more and 60 mass % or less. In addition, when obtaining the coating liquid, the addition of a diluting solvent or the like is not a necessary condition, as long as the adhesive composition P has a coatable viscosity, etc., and the diluting solvent does not need to be added. At this time, the adhesive composition P uses the polymerization solvent of the acrylic polymer (A) directly as a dilution solvent to become a coating liquid.

(2-3) Thickness of adhesive layer The thickness of the adhesive layer 3 in this embodiment is preferably 10 μm or more, particularly 15 μm or more, and further preferably 20 μm or more. In this way, the adhesive sheet 1 for workpiece processing becomes easy to exhibit good adhesive force, and for example, it becomes possible to effectively suppress the scattering of the wafer during cutting. In addition, the thickness of the adhesive layer 3 is preferably 100 μm or less, particularly preferably 50 μm or less. In this way, after the irradiation of active energy rays, the adhesive force to the processed workpiece is moderately reduced, making it easier to separate the workpiece from the workpiece processing adhesive sheet 1 .

(3) Peel off the sheet The adhesive sheet 1 for workpiece processing according to this embodiment has a release sheet 4 laminated on an adhesive layer 3 . The peeling sheet 4 may be a process material used to form the adhesive layer 3 , or may be used to protect the adhesive surface of the adhesive layer 3 until the workpiece processing adhesive sheet 1 is attached to the workpiece. In addition, in the adhesive sheet 1 for workpiece processing according to this embodiment, the release sheet 4 may be omitted.

The structure of the peeling sheet 4 is arbitrary, and a plastic film that has been peeled off by a peeling agent or the like is used as an example. Specific examples of the plastic film include polyester films such as polyethylene terephthalate, polybutylene terephthalate, and polyethylene naphthalate, and polyester films such as polypropylene and polyethylene. Olefin membrane. As the release agent, silicone-based, fluorine-based, long-chain alkyl-based release agents, etc. can be used. Among these, silicone-based release agents that are inexpensive and can obtain stable performance are preferred. The thickness of the release sheet 4 is not particularly limited, but is usually 20 μm or more and 250 μm or less.

(4)Other components The adhesive sheet 1 for workpiece processing according to this embodiment may have an adhesive layer laminated on the adhesive surface of the adhesive layer 3 . At this time, since the adhesive sheet 1 for workpiece processing according to this embodiment is provided with the adhesive layer as described above, it can be used as a dicing and die-bonding sheet. This type of cutting and die-bonding sheet can be obtained by attaching a workpiece to the surface of the adhesive layer on the opposite side to the adhesive layer 3 and cutting the adhesive layer with the workpiece, thereby obtaining a laminated, individualized adhesive layer. of wafers. The chip can be easily fixed on the object being mounted through the single-piece adhesive layer. As a material constituting the adhesive layer, it is preferable to use one containing a thermoplastic resin and a low molecular weight thermosetting adhesive component, or one containing a B-stage (semi-cured) thermosetting adhesive component.

In addition, the adhesive sheet 1 for workpiece processing according to this embodiment may have a protective film-forming layer laminated on the adhesive surface of the adhesive layer 3 . In this case, the adhesive sheet 1 for workpiece processing according to this embodiment can be used as a protective film forming and workpiece processing sheet. For example, by attaching a workpiece to the surface of the protective film-forming layer opposite to the adhesive layer 3 and cutting the protective film-forming layer with the workpiece, a protective film laminated into individual sheets can be obtained. Forming layers of wafers. As the workpiece, it is preferable to use one with a circuit formed on one side. In this case, a protective film-forming layer is usually laminated on the surface opposite to the surface on which the circuit is formed. By hardening the monolithized protective film forming layer at a specific time point, a protective film with sufficient durability can be formed on the wafer. The protective film forming layer is preferably composed of an uncured curable adhesive.

2・Physical properties of adhesive sheets for workpiece processing In the adhesive sheet 1 for workpiece processing according to this embodiment, the surface on the adhesive layer 3 side of the adhesive sheet 1 for workpiece processing is fixed to a support, and the adhesive layer 3 is irradiated with active energy rays to harden the adhesive layer 3 Then, the interlayer strength between the base material 2 and the adhesive layer 3 was measured as the peeling force when the base material 2 was peeled off from the adhesive layer 3 at a peeling angle of 180° and a peeling speed of 300mm/min. Preferably, it is preferably at least 3000mN/25mm, and further preferably at least 5000mN/25mm. By having this interlayer strength as mentioned above, residual glue when separated from the workpiece can be effectively suppressed. The adhesive sheet 1 for workpiece processing according to this embodiment can achieve the above-mentioned interlayer strength by having the above-mentioned structure and physical properties. Furthermore, the upper limit of the interlaminar strength is not particularly limited, but is generally preferably 50,000 mN/25 mm or less. In addition, the details of the method for measuring the interlaminar strength are described in the following test examples.

3. Manufacturing method of adhesive sheet for workpiece processing The manufacturing method of the adhesive sheet 1 for workpiece processing according to this embodiment is not particularly limited. A preferred manufacturing method includes the following steps: forming a coating layer 22 containing a pyrrolidone compound on one side of the base material body 21 to obtain the base material 2; applying the adhesive composition P (the coating liquid) on the base material 2. The step of forming the adhesive layer 3 on the peeling surface of the release sheet 4; and the step of bonding the surface of the base material 2 on the coating layer 22 side to the adhesive layer 3.

The coating layer 22 on one side of the substrate body 21 can be formed by a conventional method. For example, the coating agent used to form the coating layer 22 is applied by a rod coating method, a knife coating method, a roller coating method, a fin coating method, a die coating method, a gravure coating method, or the like. A coating film is formed on one side of the base body 21 and the coating film is dried to form the coating layer 22 .

In addition, the adhesive layer 3 on the peeling surface of the peeling sheet 4 can be formed by a conventional method. For example, the coating liquid of the adhesive composition P is applied to the surface by a rod coating method, a knife coating method, a roller coating method, a fin coating method, a die coating method, a gravure coating method, or the like. The peeling surface of the sheet 4 is peeled off to form a coating film, and the adhesive layer 3 can be formed by drying the coating film.

When the adhesive composition P contains the cross-linking agent (B), the acrylic polymer (A) in the coating film can be combined with the acrylic polymer (A) by changing the above-mentioned drying conditions (temperature, time, etc.) or by additionally providing heat treatment. It is preferable that the cross-linking reaction of the cross-linking agent (B) proceeds and a cross-linked structure is formed at a desired density in the adhesive layer 3 .

After the surface of the base material 2 on the coating layer 22 side is bonded to the adhesive layer 3, in order to allow the above-mentioned cross-linking reaction to fully proceed, for example, it can be left to stand for several days in an environment of 23° C. and a relative humidity of 50%. The so-called aging.

As described above, the method of transferring the adhesive layer 3 formed on the release sheet 4 to the base material 2 is preferred to achieve high production efficiency. Generally speaking, by such a transcription method, the adhesion between the base material and the adhesive layer tends to decrease. However, since the adhesive sheet 1 for workpiece processing according to this embodiment has the above-described structure and physical properties, even if it is manufactured by a related method, the adhesion between the base material 2 and the adhesive layer 3 is still high, so it can effectively Suppresses adhesive residue on the workpiece when separated from the workpiece.

Moreover, although the production efficiency will be reduced, the adhesive layer 3 formed on the release sheet 4 may not be transferred to the base material 2 in the above manner, but the adhesive layer 3 may be directly formed on the coating layer 22 of the base material 2 . At this time, the release sheet 4 may or may not be laminated on the adhesive layer 3 .

4. How to use adhesive sheets for workpiece processing The adhesive sheet 1 for workpiece processing according to this embodiment can be used for processing workpieces. That is, after the adhesive surface of the workpiece processing adhesive sheet 1 according to this embodiment is attached to the workpiece, the workpiece processing can be performed on the workpiece processing adhesive sheet 1 .

The workpiece to be processed using the adhesive sheet 1 for workpiece processing according to this embodiment is not particularly limited. Examples of the workpiece include semiconductor members such as semiconductor wafers and semiconductor packages, glass members such as glass plates, and the like. According to the adhesive sheet 1 for workpiece processing according to this embodiment, since the residual glue in the processed workpiece can be suppressed, it is preferably used in workpieces that do not generate residual glue in response to such requirements.

Examples of processing performed using the adhesive sheet 1 for workpiece processing according to this embodiment include back grinding, cutting, expanding, crystal picking, and the like. Each of the above-mentioned processes can be performed using one adhesive sheet 1 for workpiece processing, or the adhesive sheet 1 for workpiece processing can be reattached during a series of processes.

Furthermore, when the processed workpiece is separated from the adhesive sheet 1 for workpiece processing after the above-mentioned processing is completed, it is preferable to irradiate the adhesive layer 3 with active energy rays before the separation. In this way, the adhesion force to the processed workpiece can be reduced, and the above-mentioned separation can be easily performed. As the above-mentioned active energy rays, ultraviolet rays, electron rays, etc. can generally be used, and ultraviolet rays that are easy to handle are particularly preferred.

The above-mentioned ultraviolet irradiation can be performed by a high-pressure mercury lamp, a fusion lamp, a xenon lamp, etc. The amount of ultraviolet irradiation is preferably 50 mW/cm ² or more and 1000 mW/cm ² or less. The amount of ultraviolet light is preferably 50 mJ/cm ² or more, particularly 80 mJ/cm ² or more, and further preferably 100 mJ/cm ² or more. In addition, the amount of ultraviolet light is preferably 2000 mJ/cm ² or less, particularly preferably 1000 mJ/cm ² or less, and further preferably 500 mJ/cm ² or less.

As an example, a semiconductor wafer or a glass plate as a workpiece is cut on the workpiece processing adhesive sheet 1, and a plurality of semiconductor wafers are singulated, and then the workpiece processing adhesive sheet 1 is expanded as necessary. Then, the adhesive layer 3 is irradiated with active energy rays to harden the adhesive layer 3, and then the semiconductor wafer and the glass wafer are individually picked from the adhesive sheet 1 for workpiece processing.

The adhesive sheet 1 for workpiece processing according to this embodiment has the above-mentioned structure and physical properties, thereby suppressing the adhesive constituting the adhesive layer 3 from adhering to the surface of the semiconductor wafer or glass wafer to be picked. That is, adhesive residue on semiconductor wafers and glass wafers is suppressed.

In particular, the adhesive sheet 1 for workpiece processing according to this embodiment can be particularly suitably used for workpieces having recessed portions on the surface. At this time, the adhesive surface of the workpiece processing adhesive sheet 1 can be attached to the surface of the workpiece where the recessed portion exists. Examples of such workpieces having recessed portions include, for example, a semiconductor wafer having a protective film or a sealing resin layer in which minute recessed portions are formed by laser light irradiation (laser engraving), and minute recessed portions in which engraved grooves are formed. Recessed glass plates, etc. Even when the adhesive sheet 1 for workpiece processing according to this embodiment is used on a workpiece having a concave portion on its surface, it is possible to obtain a good effect of suppressing adhesive residue.

The embodiments described above are described to facilitate understanding of the present invention and are not described to limit the present invention. Therefore, each element disclosed in the above embodiment includes all design changes and equivalents within the technical scope to which the present invention belongs.

For example, the release sheet 4 may not be provided, and another layer may be provided on the surface of the base material 2 opposite to the adhesive layer 3 . [Example]

Hereinafter, the present invention will be further described in detail using Examples and the like, but the scope of the present invention is not limited to these Examples and the like.

[Manufacturing Example 1] (Preparation of base material X) (1) Preparation of coating agent 938g of water and 0.046mg of copper(II) sulfate were poured into the reaction vessel, and the temperature was raised to 60°C. Next, while maintaining 60° C., 1 kg of N-vinylpyrrolidone, 6 g of 25% ammonia water, and 34 g of 35 mass% hydrogen peroxide aqueous solution were dropped over 180 minutes. After the dropping was completed, 2 g of 25 mass% ammonia water was added. Four hours after the reaction started, the temperature was raised to 80°C, and 5 g of 35 mass% hydrogen peroxide water was added. Next, 5.5 hours after the reaction start period, 5 g of 35 mass % hydrogen peroxide water was added, and the mixture was further maintained at 80° C. for 1 hour to obtain a 50 mass % polyvinylpyrrolidone aqueous solution. The weight average molecular weight (Mw) of the polyvinylpyrrolidone thus obtained was 300,000.

40 parts by mass of the polyvinylpyrrolidone aqueous solution obtained above (solid content conversion; the same applies below), polyester-based binder resin (manufactured by Hoyo Chemical Industry Co., Ltd., product name "PLAS COAT: Z-730"), weight average molecular weight: 3000, acid value: 50.0KOHmg/g, hydroxyl value: 5.0KOHmg/g) 50 parts by mass, and a water-soluble hardener of a tetrazoline group-containing polymer (manufactured by Nippon Shokubai Co., Ltd., product name "EPOCROS: WS- 300", weight average molecular weight: 120000) 5 parts by mass were mixed to obtain a coating agent (10 mass% aqueous solution).

(2) Formation of coating layer The coating agent obtained above was applied to one side of a polyethylene terephthalate film (manufactured by Mitsubishi Chemical Corporation, product name "PET100 T-100 MITSUBISHI", thickness 100 μm) as the base material body, using Mayer Coating is performed using a meyer bar. Then, the coating film was dried at 110° C. for 1 minute to form a coating layer (pyrrolidone-based coating layer) with a thickness of 0.05 μm on the base material body, which was regarded as base material X.

[Manufacturing Example 2] (Preparation of base material Y) (1) Preparation of coating agent Mix 40 parts by mass of water-soluble polyvinyl alcohol resin (manufactured by Kuraray Co., Ltd., product name "Poval") and 50 parts by mass of alcohol-based binder resin (manufactured by Hoyo Chemical Industry Co., Ltd., product name "PLAS COAT: Z-565"), and 5 parts by mass of a water-soluble hardener of a tetrazoline group-containing polymer (manufactured by Nippon Shokubai Co., Ltd., product name "EPOCROS: WS-300", weight average molecular weight: 120000) were mixed to obtain a coating agent (10 mass % aqueous solution).

(2) Formation of coating layer The coating agent obtained above was applied to one side of a polyethylene terephthalate film (manufactured by Mitsubishi Chemical Corporation, product name "PET100 T-100 MITSUBISHI", thickness 100 μm) as the base body, using a Meyer rod. Carry out coating. Then, the coating film was dried at 110° C. for 1 minute to form a coating layer (non-pyrrolidone coating layer) with a thickness of 0.05 μm on the base material body, which was used as base material Y.

[Example 1] (1) Preparation of adhesive composition 75 parts by mass of n-butyl acrylate (BA), 10 parts by mass of methyl methacrylate (MMA), and 15 parts by mass of 2-hydroxyethyl acrylate (HEA) were polymerized by a solution polymerization method to obtain (methyl ) acrylate copolymer. This (meth)acrylate copolymer was mixed with 30 g (equivalent to 80 mol% of 2-hydroxyethyl acrylate) of methacryloxy group based on 100 g of the (meth)acrylate copolymer. Ethyl isocyanate (MOI) is reacted to obtain an acrylic polymer having an active energy ray curable group introduced into the side chain. The weight average molecular weight (Mw) of this acrylic polymer is 600,000.

100 parts by mass of the acrylic polymer having an active energy ray curable group introduced into the side chain obtained above was added with 2-hydroxy-1-{4-[4-(2-hydroxy-2- 7 parts by mass of methyl-propyl)-benzyl]phenyl}-2-methyl-propan-1-one (manufactured by BASF, product name "Omnirad 127"), trimethylol as a cross-linking agent 0.2 parts by mass of propane-modified tomycin diisocyanate (manufactured by Tosoh Corporation, product name "Coronate L") was mixed in a solvent to obtain a coating liquid of an adhesive composition.

(2) Formation of adhesive layer A release sheet made of a polyethylene terephthalate (PET) film with a thickness of 38 μm and a silicone-based release agent layer formed on one side of the film (manufactured by LINTEC, product name "SP-PET381031") The coating liquid of the above-mentioned adhesive composition is applied to the release surface, and dried by heating to form an adhesive layer with a thickness of 25 μm on the release sheet.

(3) Production of adhesive sheets for workpiece processing The adhesive sheet for workpiece processing was obtained by bonding the exposed surface of the adhesive layer formed in the above-mentioned step (2) to the coating layer side surface of the base material X produced in Production Example 1.

[Examples 2 to 6, Comparative Examples 1 to 2] In addition to the types and proportions of each monomer constituting an acrylic polymer ((meth)acrylate copolymer) having an active energy ray-curable group introduced into the side chain, and the weight average molecular weight (Mw) of the acrylic polymer ) except that the adhesive sheet for workpiece processing was produced in the same manner as in Example 1 except that the changes are as shown in Table 1.

[Comparative Examples 3~4] In addition to the types and proportions of each monomer constituting an acrylic polymer ((meth)acrylate copolymer) having an active energy ray-curable group introduced into the side chain, and the weight average molecular weight (Mw) of the acrylic polymer ) was changed as shown in Table 1, and the base material

[Comparative example 5] An adhesive sheet for workpiece processing was produced in the same manner as in Example 1 except that the base material X was changed to the base material Y.

[Comparative example 6] Ethylene-methacrylic acid copolymer (EMAA) (manufactured by DOW-MITSUI POLYCHEMICALS CO., LTD., product name "NUCREL N0903HC") is extruded through a small T-type die extruder (manufactured by Toyo Seiki Seisakusho Co., Ltd., product name An EMAA film with a thickness of 80 μm obtained by extrusion molding of "LABO PLASTOMILL") was irradiated with an electron beam of 110 kGy for 2.2 seconds. An adhesive sheet for workpiece processing was produced in the same manner as in Example 1 except that the EMAA film thus obtained was used instead of the base material X.

Here, the details of the simple codes and the like described in Table 1 are as follows. BA: n-butyl acrylate MMA: methyl methacrylate HEA: 2-hydroxyethyl acrylate ACMO: N-Acrylylmorpholine DMAA: N,N-dimethylacrylamide 2EHA: 2-ethylhexyl acrylate VAc: vinyl acetate

The weight average molecular weight (Mw) mentioned above is the weight average molecular weight of converted standard polystyrene measured under the following conditions (GPC measurement) using gel permeation chromatography (GPC). >Measurement conditions> ・Measuring device: Made by Tosoh Corporation, HLC-8320 ・GPC string (pass in the following order): Made by Tosoh Corporation TSK gel SuperH-H TSK gel superHM-H TSK gel superH2000 ・Measurement solvent: tetrahydrofuran ・Measuring temperature: 40℃

[Test Example 1] (Measurement of storage modulus of base material) Regarding the base materials produced and used in the Examples and Comparative Examples, the storage modulus at 25° C. was measured using the following apparatus and conditions. The results are shown in Table 1. Measuring device: Dynamic modulus measuring device, manufactured by A&D Company, Limited, product name "RHEOVIBRON DDV-01FP" Test starting temperature: 0℃ Test end temperature: 200℃ Heating rate: 3℃/min Frequency: 11Hz Amplitude: 20μm

[Test Example 2] (Calculation of glass transition temperature) The glass transition temperature (Tg) of the acrylic polymer prepared in Examples and Comparative Examples and having an active energy ray curable group introduced into the side chain was calculated by Fox's equation. The results are shown in Table 1.

[Test Example 3] (Measurement of interlaminar strength) It consists of a base material, an adhesive layer composed of a highly adhesive ultraviolet curable adhesive laminated on one side of the base material, and a release sheet laminated on the side of the adhesive layer opposite to the base material. The surface of the base material side of the high-adhesion UV adhesive sheet (manufactured by LINTEC, product name "Adwill D-510T") composed of three layers of the material is separated by a double-sided adhesive tape (manufactured by LINTEC, product name "TackLiner" ), fixed on one side of the stainless steel plate (SUS304#600) as the support.

Next, the release sheet is peeled off from the high-adhesion UV adhesive sheet to expose the surface of the adhesive layer opposite to the base material. Next, the release sheet was peeled off from the adhesive sheet for workpiece processing manufactured in Examples and Comparative Examples to expose the adhesive surface, which was attached to the exposed surface of the adhesive layer in the high-adhesion UV adhesive sheet.

Next, the adhesive layer in the adhesive sheet for workpiece processing is irradiated with ultraviolet rays (illuminance: 230mW/cm ² , light intensity: 190mJ/cm ² ) from the surface of the adhesive sheet for workpiece processing on the base material side, so that the adhesive layer for workpiece processing is adhered. The adhesive layer of the sheet and the adhesive layer of the high-adhesion UV adhesive sheet are hardened.

Thereafter, a universal tensile testing machine (manufactured by Shimadzu Corporation, product name "AUTOGRAPH AG-IS") was used to process the base material of the adhesive sheet for workpiece processing from the workpiece at a peeling angle of 180° and a peeling speed of 300mm/min. Peel off the adhesive layer of the adhesive sheet and measure the peeling force at this time (mN/25mm). Then, the peeling force was used as the interlaminar strength (mN/25mm). The results are shown in Table 1.

Moreover, in the adhesive sheets for workpiece processing of Examples 1 to 3, since the interlayer strength between the adhesive layer of the adhesive sheet for workpiece processing and the base material was too high, cracks occurred in the base material or the adhesive layer, so the measurement could not be performed.

[Test Example 4] (Evaluation of residual glue) A laser marking device (manufactured by KEYENCE, product name "MD-S9910A") was used to engrave the mirror surface of the silicon wafer. As a result, the mirror surface has a groove with a width of about 50 μm and a depth of about 25 μm when viewed in cross section.

Next, the exposed adhesive surface was peeled off from the adhesive sheet for workpiece processing produced in Examples and Comparative Examples, and the mirror surface after laser engraving was attached using a 2kg rubber roller and left for 20 minutes.

Next, the adhesive layer in the adhesive sheet for workpiece processing is irradiated with ultraviolet rays (illuminance: 230mW/cm ² , light intensity: 190mJ/cm ² ) from the surface of the adhesive sheet for workpiece processing on the base material side, so that the adhesive layer for workpiece processing is adhered. The adhesive layer of the tablet hardens.

Thereafter, the above-mentioned mirror surface is separated from the adhesive sheet for workpiece processing, and the residual glue (adhesion of adhesive) on the engraved portion of the mirror surface is visually confirmed. As a result, those with no glue residue were evaluated as "◎", those with a slight glue residue were evaluated as "O", and those with glue residue were evaluated as "×". The results are shown in Table 1.

[Test Example 5] (Evaluation of missing corners) The release sheet was peeled off from the adhesive sheet for workpiece processing manufactured in the Example and Comparative Example, and the exposed adhesive layer was applied using a tape pasting machine (manufactured by LINTEC, product name "Adwill RAD2500m/12"), and 6 Inch silicon wafers and ring frames for dicing. Next, after cutting the adhesive sheet for workpiece processing according to the outer diameter of the annular frame, a cutting device (manufactured by DISCO: DFD-651) was used to cut from the silicon wafer side under the following cutting conditions to obtain 8 mm Square chip.

>Cutting conditions> ・Wafer thickness: 350μm ・Cutting device: Made by DISCO, product name "DFD-651" ・Blade: Made by DISCO, product name "NBC-2H205027HECC" ・Blade width: 0.025~0.030mm ・Blade first output: 0.640~0.760mm ・Blade rotation number: 30000rpm ・Cutting speed: 80mm/sec ・Depth of cutting into the base material: 20μm ・Cutting water volume: 1.0L/min ・Cutting water temperature: 20℃

Among the obtained 8 mm square wafers, the center part of the adhesive sheet for workpiece processing and the position near it were observed to see if there were any chipped corners (defects at the end of the wafer). Specifically, an electron microscope (manufactured by KEYENCE, product name "VHZ-100", magnification: 300 times) was used to observe the 50 wafer edge in the flow direction (MD direction) during the production of the base material body and in the MD direction. 50 wafer edge in vertical direction (CD direction). Then, a defect having a width or depth of 100 μm or more is determined to be a chipped corner, and the number of wafers having a chipped corner is counted. Based on this result, the missing angle is evaluated as follows as a standard. The evaluation results are shown in Table 1. 〇: The number of wafers with chipped corners does not reach 5. ×: The number of wafers with chipped corners is 5 or more.

[Table 1] base material Acrylic polymer Tg(℃) Interlayer strength (mN/25mm) Evaluation of residual glue Comments on missing corners Kind Storage modulus (MPa) composition Mw Example 1 Base material 1800 BA75/MMA10/HEA15-80% 600,000 -39 rupture occurs ◎ ○ Example 2 1800 BA75/ACMO10/HEA15-80% 600,000 -37 rupture occurs ◎ ○ Example 3 1800 BA75/DMAA10/HEA15-80% 600,000 -38 rupture occurs ◎ ○ Example 4 1800 2EHA73/DMAA12/HEA15-80% 600,000 -50 12000 ◎ ○ Example 5 1800 2EHA75/VAc10/HEA15-80% 600,000 -56 6800 ○ ○ Example 6 1800 2EHA80/HEA20-80% 600,000 -61 5400 ○ ○ Comparative example 1 1800 2EHA40/VAc40/HEA20-80% 600,000 -27 450 × ○ Comparative example 2 1800 2EHA50/MMA30/HEA20-80% 600,000 -25 305 × ○ Comparative example 3 Base material Y 1770 2EHA73/DMAA12/HEA15-80% 600,000 -50 270 × ○ Comparative example 4 1770 2EHA75/VAc10/HEA15-80% 600,000 -56 300 × ○ Comparative example 5 1770 BA75/MMA10/HEA15-80% 600,000 -39 250 × ○ Comparative example 6 polyolefin film 140 BA75/MMA10/HEA15-80% 600,000 -39 20000 ○ ×

It can be seen from Table 1 that the adhesive sheet for workpiece processing obtained in the Example can effectively suppress the residual glue on the workpiece when it is separated from the workpiece. In addition, the occurrence of chipped corners during cutting can also be suppressed. [Industrial Availability]

The adhesive sheet for workpiece processing of the present invention is suitable for use on workpieces that require no adhesive residue, especially when processing workpieces with minute recesses on the surface.

1: Adhesive sheet for workpiece processing 2:Substrate 21:Substrate body 22:Coating layer 3: Adhesive layer 4: Peel off the sheet

[Fig. 1] A cross-sectional view of an adhesive sheet for workpiece processing according to an embodiment of the present invention.

1: Adhesive sheet for workpiece processing

2:Substrate

21:Substrate body

22:Coating layer

3: Adhesive layer

4: Peel off the sheet

Claims (10)

An adhesive sheet for workpiece processing, including: a base material, and an adhesive layer laminated on one side of the base material, The adhesive layer is composed of an active energy ray-curable adhesive composed of an adhesive composition containing an acrylic polymer having an active energy ray-curable group introduced into a side chain, The glass transition temperature (Tg) of the above-mentioned acrylic polymer is -80°C or more and -30°C or less, A coating layer containing a pyrrolidone compound is formed on the surface of the base material that is in contact with the adhesive layer. The adhesive sheet for workpiece processing according to claim 1, wherein the acrylic polymer has a structure derived from an alkyl (meth)acrylate in the main chain of the polymer, The acrylic acid group in the alkyl (meth)acrylate has 1 to 4 carbon atoms. The adhesive sheet for workpiece processing according to claim 1, wherein the acrylic polymer has a structure derived from a monomer containing a functional group in the main chain of the polymer, The proportion of the structural portion derived from the functional group-containing monomer in the entire acrylic polymer is 0.1% by mass or more and 12% by mass or less. The adhesive sheet for workpiece processing according to claim 1, wherein the pyrrolidone compound is a polymer having vinylpyrrolidone as its main structural unit. The adhesive sheet for workpiece processing according to claim 1, wherein the storage modulus of the above-mentioned base material at 25°C is 1000 MPa or more. The adhesive sheet for workpiece processing according to claim 5, wherein the above-mentioned base material uses a polyethylene terephthalate film as the base material body. The adhesive sheet for workpiece processing described in claim 1 is a cutting sheet. A method for manufacturing an adhesive sheet for workpiece processing, which is a method for manufacturing an adhesive sheet for workpiece processing as described in any one of claims 1 to 7, including: The step of forming a coating layer containing a pyrrolidone compound on one side of the base material body to obtain the above base material; The step of applying the above-mentioned adhesive composition on the release surface of the release sheet to form the above-mentioned adhesive layer; and The step of laminating the surface of the coating layer side of the above-mentioned base material to the above-mentioned adhesive layer. A method of manufacturing an adhesive sheet for workpiece processing, which is the manufacturing method of an adhesive sheet for workpiece processing as described in claim 3, including: A (meth)acrylate copolymer is prepared by copolymerizing a functional group-containing monomer in an amount of 5 mass % or more and 35 mass % or less. In the (meth)acrylate copolymer, the functional group-containing monomer is The step of reacting a compound with an active energy ray curable group to produce an acrylic polymer having an active energy ray curable group introduced into a side chain, and preparing an adhesive composition containing the acrylic polymer; The step of forming a coating layer containing a pyrrolidone compound on one side of the base material body to obtain the above-mentioned base material; The step of applying the above-mentioned adhesive composition on the release surface of the release sheet to form the above-mentioned adhesive layer; and The step of laminating the surface of the coating layer side of the above-mentioned base material to the above-mentioned adhesive layer. The method of manufacturing an adhesive sheet for workpiece processing according to claim 9, wherein the amount of the active energy ray-curable group-containing compound having the above functional group relative to the amount of the functional group of the functional group-containing monomer is More than 60 mol%, less than 99 mol%.