Method for manufacturing wafer

Abstract

The purpose of the present invention is to provide a method for manufacturing a wafer to which a wafer support system is applied, capable of achieving excellent recess and projection absorption, and effectively suppressing generation of voids when bonding the wafer and an adhesive material. The wafer manufacturing method includes: (a) a step of bonding the wafer, the adhesive material, and a support to form a laminate composed of a wafer / adhesive material / support; (c) a step of subjecting the wafer to a heat treatment, a machining treatment, a chemical treatment, a physical treatment, a laser processing treatment, and / or a film formation treatment; (d) a step of removing the support from the laminate; and (e) a step of removing the adhesive material from the laminate composed of the wafer / adhesive material, where in the wafer manufacturing method, a melt viscosity η* a of at least one layer A in the adhesive material at a temperature Ta at the time of formation of the laminate when the temperature is raised from room temperature at a temperature raising speed of 10°C / minute in step (a) is 5,0x103 to 5.0x105Pa•s.

Description

Wafer manufacturing method

[0001] The present invention relates to a wafer manufacturing method (wafer support system) in which a wafer is processed while being temporarily fixed to a support, and more specifically, to a manufacturing method in which the handling ability of the wafer is improved by temporarily fixing the wafer to the support, making it possible to use the wafer in a wide variety of processing processes, while also having excellent irregularity absorption properties and being able to effectively suppress the generation of voids when bonding the wafer.

[0002] In semiconductor manufacturing processes, temporary fixation is often necessary or desirable during wafer processing due to factors such as wafer thinness and fragility. For example, to achieve high integration of semiconductor devices, thin grinding of wafers formed with functional layers for semiconductor devices is widely practiced. However, when wafers are ground to an extremely thin thickness, tape alone is no longer sufficient to support the wafer. Therefore, it has been proposed to temporarily fix the wafer to a hard carrier (support) via an adhesive material before processing after thin grinding. Wafer manufacturing methods using such supports are called wafer support systems. Adhesive materials for use in wafer support systems have been researched for some time. For example, Patent Document 1 proposes controlling the post-curing elastic modulus by photo- or thermal curing to achieve sufficient adhesive strength during wafer processing and to remove the support substrate after the wafer processing process without damaging the wafer or leaving adhesive residue. Patent Document 2 also proposes achieving a gel fraction of the adhesive composition above a predetermined value when the curable adhesive component of the adhesive composition is crosslinked and cured.

[0003] When bonding to a wafer, particularly when bonding to a wafer having an uneven surface, voids may occur at the bonding interface, and there is a need to prevent this.

[0004] JP 2015-29105 A JP 2015-149432 A

[0005] In view of the above technical background, an object of the present invention is to provide a wafer manufacturing method that applies a wafer support system, which realizes excellent irregularity absorption and can effectively suppress the generation of voids when bonding a wafer to an adhesive material.

[0006] As a result of extensive investigations, the present inventors have found that the above-mentioned problems can be solved by controlling the viscoelasticity of an adhesive material to be bonded to a wafer and by setting the melt viscosity at the temperature of bonding to the wafer within a specific numerical range, thereby realizing excellent irregularity absorbability and effectively suppressing the generation of voids during bonding to the wafer, and have completed the present invention. That is, the present invention is a wafer manufacturing method comprising: [1] a step of bonding a wafer, an adhesive material, and a support to form a laminate consisting of a wafer / adhesive material / support, (c) a step of subjecting the wafer to a heat treatment, a mechanical processing treatment, a chemical treatment, a physical treatment, a laser processing treatment, and / or a film formation treatment, (d) a step of removing the support from the laminate, and (e) a step of removing the adhesive material from the laminate consisting of a wafer / adhesive material, （ａ） The melt viscosity η of at least one layer A in the adhesive material ＊ （ａ） is 5.0 x 10 ３ ~5.0 x 10 ５ The present invention relates to a method for manufacturing a wafer, wherein the surface roughness is Pa·s.

[0007] [2] to [9] below are all preferred aspects or embodiments of the present invention. [2] The wafer manufacturing method according to [1], further comprising the step of (b) curing the adhesive by heating or ultraviolet irradiation. [3] The wafer manufacturing method according to [1] or [2], further comprising the step of (b) curing the adhesive by heating or ultraviolet irradiation. [4] The wafer manufacturing method according to [1] or [2], wherein the loss coefficient tan δ of the layer A at 130°C is 0.01 to 0.40. [4] The temperature T of the layer A in the step (a) （ａ）[5] The method for manufacturing a wafer according to any one of [1] to [4], wherein the bonding pressure in step (a) is 0.05 to 1.0 MPa and the bonding time is 10 to 600 seconds. [6] The method for manufacturing a wafer according to any one of [1] to [4], wherein the temperature T （ａ） The melt viscosity η of the layer A at a temperature 30° C. lower than ＊ （ａ） ' is 1.0 x 10 2 ~1.0 x 10 3 [7] The method for producing a wafer according to any one of [1] to [5], wherein the melt viscosity η of the layer A after curing in step (b) is Pa·s. ＊ （ｂ） is 1.0 x 10 5 ~1.0 x 10 ６ [8] The method for manufacturing a wafer according to any one of [1] to [7], wherein the unevenness of the surface of the wafer on the side to be bonded to the adhesive material is 5 μm or more. [9] A method for manufacturing an electronic device, comprising a step of manufacturing a wafer by the method for manufacturing a wafer according to any one of [1] to [8].

[0008] According to the wafer manufacturing method of the present invention, the handleability of thin or fragile wafers is improved, the wafers can be stably processed in a wide range of processing processes, and the generation of voids during wafer bonding can be effectively suppressed. This allows the wafer to be stably fixed and processed in each subsequent process, and it becomes possible to perform multiple and / or wide-ranging processes on the wafer with high productivity and yield without damaging electronic components such as functional layers formed on the wafer, which greatly contributes to improving the productivity of electronic components such as electronic devices.

[0009] The present invention provides a method for manufacturing a wafer, the method comprising: (a) a step of bonding a wafer, an adhesive, and a support to form a laminate consisting of wafer / adhesive / support; (c) a step of subjecting the wafer to a heat treatment, a mechanical processing treatment, a chemical treatment, a physical treatment, a laser processing treatment, and / or a film formation treatment; (d) a step of removing the support from the laminate; and (e) a step of removing the adhesive from the laminate consisting of wafer / adhesive, wherein the temperature T at the time of formation of the laminate when the temperature is increased from room temperature at a temperature increase rate of 10°C / min in the step (a) is （ａ） The melt viscosity η of at least one layer A in the adhesive material ＊ （ａ） is 5.0 x 10 ３ ~5.0 x 10 ５ That is, the present invention is a method for manufacturing a wafer, which includes the steps (a), (c), (d), and (e) described below, and uses a wafer, an adhesive material, and a support.

[0010] The adhesive material used in the manufacturing method of the present invention is an adhesive material for use in a wafer support system, and is used to temporarily fix a wafer and a support. In the manufacturing method of the present invention, the wafer and the support are temporarily fixed to form a laminate consisting of wafer / adhesive / support. The adhesive material has a temperature T （ａ） Melt viscosity η at ＊ （ａ） is 5.0 x 10 ３ ~5.0 x 10 ５ The formation of the laminate means that a wafer and a support are bonded together via the adhesive layer to complete a laminate consisting of a wafer / adhesive / support.

[0011] The temperature T of the adhesive layer A at the time of forming the laminate when the temperature is increased from room temperature at a temperature increase rate of 10°C / min （ａ） Melt viscosity η at ＊ （ａ） is 5.0 x 10３ ~5.0 x 10 ５ By virtue of the viscosity being Pa·s, the pressure-sensitive adhesive material achieves excellent unevenness absorption properties, and as a result, the manufacturing method of the present invention can achieve remarkable technical effects that are of great practical value, such as being able to effectively suppress the generation of voids when bonding to a wafer.

[0012] The temperature T of the adhesive layer A at the time of forming the laminate when the temperature is increased from room temperature at a temperature increase rate of 10°C / min （ａ） Melt viscosity η at ＊ （ａ） The mechanism by which excellent irregularity absorbency and void suppression can be achieved by having the viscosity be within the above range is not necessarily clear, but it is presumed that there is some relationship between the fact that, when the melt viscosity is neither too high nor too low at the formation temperature of a laminate consisting of wafer / adhesive / support (the temperature at which the wafer and support are bonded together via the adhesive layer to complete a laminate consisting of wafer / adhesive / support) and the fact that the laminate can properly follow the irregularities on the wafer surface in the bonding step and can properly suppress the foaming phenomenon due to excessive fluidity.

[0013] The temperature T of the adhesive layer A at the time of forming the laminate when the temperature is increased from room temperature at a temperature increase rate of 10°C / min （ａ） Melt viscosity η at ＊ （ａ） can be measured by a method conventionally known in the art, for example, by using a dynamic viscoelasticity measuring device. More specifically, it can be measured by, for example, the method described in the Examples of the present application. The temperature T of the adhesive layer A at the time of forming the laminate when the temperature is increased from room temperature at a temperature increase rate of 10°C / min （ａ） Melt viscosity η at ＊ （ａ） can be appropriately adjusted by changing the formulation of the adhesive layer A, for example, by changing the molecular weight of (a) the acrylic polymer, changing the types and blending amounts of (b) the isocyanate crosslinking agent, (c) the polyfunctional acrylate, (d) the organic peroxide, etc., selecting (d) an organic peroxide having a desired one-minute half-life temperature, or blending another plasticizer.

[0014] The temperature T of the adhesive layer A at the time of forming the laminate when the temperature is increased from room temperature at a temperature increase rate of 10°C / min （ａ） Melt viscosity η at ＊ （ａ） is 1.0 x 10 4 It is preferable that the viscosity is 1.0×10 Pa·s or more. 5 The temperature T of the adhesive layer A at the time of forming the laminate when the temperature is increased from room temperature at a temperature increase rate of 10° C. / min is particularly preferably 100 Pa·s or more. （ａ） Melt viscosity η at ＊ （ａ） is 4.0 x 10 ５ It is preferable that it is Pa·s or less.

[0015] The temperature T of the layer A in step (a) （ａ） The melt viscosity η of the adhesive layer A at a temperature 30°C lower than ＊ （ａ） There is no particular limitation on the thickness of the adhesive layer, but from the viewpoint of conformability to the irregularities on the wafer surface at the beginning of the lamination process and suppression of foaming due to excessive fluidity during lamination, it is preferable to use an adhesive layer having a thickness of 1.0 × 10 2 ~1.0 x 10 3 The temperature T of the layer A in step (a) is preferably 1 Pa·s. （ａ） The melt viscosity η of the adhesive layer A at a temperature 30°C lower than ＊ （ａ） ' is 2.0 x 10 2 It is preferable that the viscosity is 5.0×10 Pa·s or more. 2 It is more preferable that the viscosity is 8.0×10 Pa·s or more. 2 The temperature T of the adhesive layer A in the step (a) is preferably not more than Pa·s. （ａ） The melt viscosity η of the adhesive layer A at a temperature 30°C lower than ＊ （ａ） The measurement and adjustment methods for η ＊ （ａ） This is similar to what has been explained above with respect to

[0016] The minimum melt viscosity η of the adhesive layer A when heated from room temperature at a heating rate of 10°C / min ＊ ｍｉｎ , and the temperature T ｍｉｎThere is no particular limitation on the minimum melt viscosity η ＊ ｍｉｎ is 1.0 x 10 ２ If the viscosity is not less than Pa·s, excessive flow during lamination can be suppressed, and the foaming phenomenon can be suppressed, which is preferable. ｍｉｎ If the temperature is 120° C. or less, it is estimated that bonding can be performed at a relatively low temperature, which is preferable from the viewpoint of productivity and the like.

[0017] The minimum melt viscosity η of the adhesive layer A when heated from room temperature at a heating rate of 10°C / min ＊ ｍｉｎ , and the temperature T ｍｉｎ The measurement method and adjustment method of η ＊ （ａ） This is similar to what has been explained above with respect to

[0018] Minimum melt viscosity η of adhesive layer A ＊ ｍｉｎ is 1.0 x 10 １ More preferably, it is 2.0×10 Pa·s or more. ２ The minimum melt viscosity η of the adhesive layer A is particularly preferably η Pa·s or more. ＊ ｍｉｎ is 1.0 x 10 ３ It is preferable that the viscosity is 5.0×10 Pa·s or less. ２ The minimum melt viscosity η of the adhesive layer A is preferably 0.01 Pa·s or less. ＊ ｍｉｎ The temperature T ｍｉｎ The minimum melt viscosity η of the adhesive layer A is more preferably 115° C. or less. ＊ ｍｉｎ The temperature T ｍｉｎ is more preferably 90°C or higher, and particularly preferably 100°C or higher.

[0019] In measurements of the adhesive layer A using a dynamic viscoelasticity measuring device, the loss coefficient tan δ at 130°C when the temperature is increased from room temperature at a heating rate of 10°C / min is not particularly limited, but is preferably 0.01 to 0.40. When the tan δ at 130°C is 0.01 to 0.40, it is possible to achieve both excellent irregularity absorption and void suppression at an even higher level. The mechanism by which the adhesive layer A having a tan δ at 130°C of 0.01 to 0.40 can achieve both excellent irregularity absorption and void suppression at an even higher level is not necessarily clear, but it is presumed that there is some relationship between the fact that the tan δ is in an appropriate range at 130°C, which is close to the temperature in a normal lamination process, and the fact that it can achieve both the properties of a viscous material suitable for absorbing irregularities and the properties of an elastic material suitable for void suppression.

[0020] The method for measuring and adjusting tan δ of the adhesive layer A at 130°C is ＊ （ａ） The tan δ of the adhesive layer A at 130° C. is more preferably 0.02 or more and 0.2 or less, and particularly preferably 0.03 or more and 0.1 or less.

[0021] The tan δ of the adhesive layer A at 70°C is not particularly limited, but from the viewpoints of conformability to the irregularities on the wafer surface at the beginning of the lamination process and suppression of foaming due to excessive fluidity during lamination, it is preferably 0.1 or more and 1.5 or less, more preferably 0.3 or more and 1.0 or less. The tan δ of the adhesive layer A at 100°C is not particularly limited, but from the viewpoints of conformability to the irregularities on the wafer surface at the beginning of the lamination process and suppression of foaming due to excessive fluidity during lamination, it is preferably 0.1 or more and 1.5 or less, more preferably 0.3 or more and 1.0 or less. The adhesive component used in the adhesive layer A is not particularly limited, and for example, adhesives containing rubber-based, acrylic-based, epoxy-based, urethane-based, allyl-based, silicone-based, fluorine-based, and polyimide-based adhesive components can be used as appropriate. The adhesive layer A preferably contains an acrylic polymer because of its heat resistance and ease of adjusting the adhesive strength.

[0022] The adhesive component is preferably a curable adhesive component because curing it before wafer processing reduces the likelihood of voids occurring during heat treatment during the wafer manufacturing process. Examples of the curable adhesive component include a photocurable adhesive component that crosslinks and hardens when irradiated with light, and a thermosetting adhesive component that crosslinks and hardens when heated. In particular, examples of the thermosetting adhesive component include a thermosetting adhesive component that contains a monomer, oligomer, or polymer such as acrylic, epoxy, urethane acrylate, epoxy acrylate, silicone acrylate, or polyester acrylate as a curing component, and that contains a thermal polymerization initiator.

[0023] (a) Acrylic Polymer Among the above, the acrylic polymer can be obtained, for example, by synthesizing in advance a (meth)acrylic polymer having a functional group in the molecule (hereinafter referred to as functional group-containing (meth)acrylic polymer), and then reacting it with a compound having in the molecule a functional group reactive with the functional group and a radically polymerizable unsaturated bond (hereinafter referred to as functional group-containing unsaturated compound).

[0024] Examples of the functional group-containing (meth)acrylic polymer include those obtained by copolymerizing, by a conventional method, an alkyl acrylate and / or alkyl methacrylate ester, the main monomer of which is an alkyl group having a carbon number of typically 2 to 18, with a functional group-containing monomer and, if necessary, with other modifying monomers copolymerizable therewith. The weight-average molecular weight of the functional group-containing (meth)acrylic polymer is typically about 200,000 to 2,000,000.

[0025] Examples of the functional group-containing monomer include carboxyl group-containing monomers such as acrylic acid and methacrylic acid, hydroxyl group-containing monomers such as hydroxyethyl acrylate and hydroxyethyl methacrylate, epoxy group-containing monomers such as glycidyl acrylate and glycidyl methacrylate, isocyanate group-containing monomers such as isocyanate ethyl acrylate and isocyanate ethyl methacrylate, and amino group-containing monomers such as aminoethyl acrylate and aminoethyl methacrylate.

[0026] Examples of the other copolymerizable modifying monomers include various monomers used in general (meth)acrylic polymers, such as vinyl acetate, acrylonitrile, and styrene.

[0027] The functional group-containing unsaturated compound to be reacted with the functional group-containing (meth)acrylic polymer can be the same as the functional group-containing monomer described above, depending on the functional group of the functional group-containing (meth)acrylic polymer. For example, when the functional group of the functional group-containing (meth)acrylic polymer is a carboxyl group, an epoxy group-containing monomer or an isocyanate group-containing monomer is used. When the functional group is a hydroxyl group, an isocyanate group-containing monomer is used. When the functional group is an epoxy group, a carboxyl group-containing monomer or an amide group-containing monomer such as acrylamide is used. When the functional group is an amino group, an epoxy group-containing monomer is used. The (a) acrylic polymer may be used alone or in combination of two or more.

[0028] (b) Isocyanate Crosslinking Agent The pressure-sensitive adhesive layer A may contain (b) an isocyanate crosslinking agent. As the (b) isocyanate crosslinking agent, a HDI (hexamethylene diisocyanate)-based isocyanate crosslinking agent is preferred. Examples of commercially available HDI-based isocyanate crosslinking agents include D170N (manufactured by Mitsui Chemicals, Inc.) and Coronate HX (manufactured by Tosoh Corporation). The (b) isocyanate crosslinking agent may be used alone or in combination of two or more.

[0029] (b) By adjusting the amount of the isocyanate crosslinking agent, the initial crosslinking degree of the adhesive layer A is appropriately adjusted, and the melt viscosity η is within the specific numerical range required by the present invention. ＊ （ａ） This can be achieved more easily, and （ａ） Melt viscosity η at a temperature 30 ° C lower than ＊ （ａ）' and other desirable physical properties can be more easily realized. More specifically, the blending amount of the (b) isocyanate crosslinking agent is preferably 0.01 to 8 parts by mass relative to 100 parts by mass of the (a) acrylic polymer. The blending amount is more preferably 0.01 to 3 parts by mass. When the (b) isocyanate crosslinking agent is in this range, it can function sufficiently as a crosslinking agent, and physical properties such as the unevenness absorbency of the pressure-sensitive adhesive layer A can be more easily realized.

[0030] (c) Polyfunctional Acrylate The pressure-sensitive adhesive layer A may contain, as a curing component, for example, a monomer, oligomer, or polymer such as acrylic, epoxy, urethane acrylate, epoxy acrylate, silicone acrylate, or polyester acrylate. The oligomer or monomer as the curing component generally has a molecular weight of 10,000 or less and has 1 to 40 radically polymerizable unsaturated bonds in the molecule. From the viewpoint of three-dimensional reticulation, the number of radically polymerizable unsaturated bonds is preferably 2 or more.

[0031] Examples of the oligomer or monomer as the curing component include trimethylolpropane triacrylate, tetramethylolmethane tetraacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol monohydroxypentaacrylate, dipentaerythritol hexaacrylate, and the same methacrylates as above. Other examples include 1,4-butylene glycol diacrylate, 1,6-hexanediol diacrylate, polyethylene glycol diacrylate, commercially available oligoester acrylates, urethane acrylates, and the same methacrylates as above. These polyfunctional oligomers or monomers may be used alone or in combination of two or more.

[0032] In one embodiment, the adhesive layer A may contain (c) a polyfunctional acrylate as a curing component. The (c) polyfunctional acrylate may have two or more functional groups, and there are no other limitations. However, a bifunctional or trifunctional acrylate is preferred. The elastic modulus of the adhesive layer A after curing is thought to depend on the (c) polyfunctional acrylate. The use of a bifunctional or trifunctional acrylate can impart appropriate toughness and more easily achieve desirable properties such as easy peeling of the adhesive without leaving any adhesive residue after wafer processing. Examples of bifunctional or trifunctional acrylates include trimethylolpropane triacrylate, trimethylolpropane PO-modified triacrylate, and polyester acrylate. The (c) polyfunctional acrylates may be used alone or in combination of two or more.

[0033] There are no particular restrictions on the amount of (c) polyfunctional acrylate blended, but it is preferably 10 to 100 parts by mass per 100 parts by mass of (a) acrylic polymer. The blended amount is more preferably 30 to 60 parts by mass. By blending the (c) polyfunctional acrylate in an amount of 10 parts by mass or more, it is possible to effectively harden the adhesive and achieve easy peeling properties upon peeling. By blending the (c) polyfunctional acrylate in an amount of 100 parts by mass or less, it is possible to impart appropriate toughness and more effectively prevent adhesive residue due to excessive adhesive force.

[0034] (d) Organic Peroxide In one embodiment, the adhesive layer A may contain a curable adhesive component. In this case, (d) organic peroxide may be contained as a thermal polymerization initiator. Examples of (d) organic peroxide include those that decompose by heat to generate active radicals that initiate polymerization curing. Specific examples include t-butylperoxy-2-ethyl hexanoate, bis(4-methylbenzoyl)peroxide, benzoyl peroxide, 1,1-bis(t-hexylperoxy)cyclohexane, 1,1-bis(t-butylperoxy)cyclohexane, 2,2-bis(4,4-bis-(t-butylperoxy)cyclohexyl)propane, t-hexylperoxyisopropyl monocarboxylate, t-butylperoxyacetate, 2,2-bis-( t-butylperoxy)butane, 4,4-bis-(t-butylperoxy)n-butyl pentanoate, bis-t-hexyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane, bis(2-t-butylperoxyisopropyl)benzene, t-butylcumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexyne, and diisopropylbenzene hydroperoxide.

[0035] Among (d) organic peroxides, commercially available ones are not particularly limited, but suitable examples include Perbutyl O, Niper BMT, Niper BW, Perhexa HC, Perhexa C, Pertetra A, Perhexyl I, Perbutyl A, Perhexa 22, Perhexa V, Perhexyl D, Percumyl D, Perhexa 25B, Perbutyl C, Perhexyne 25B, and Percumyl P (all manufactured by NOF Corporation), Perkadox 12XL25 (manufactured by Nouryon Chemical Co., Ltd.), etc. The (d) organic peroxides may be used alone or in combination of two or more.

[0036] It is preferable to use, as the (d) organic peroxide, one having a one-minute half-life temperature of 130 to 170°C. When the one-minute half-life temperature is 130°C or higher, premature curing is suppressed when the adhesive layer A is heated from room temperature at a temperature increase rate of 10°C / min. When the one-minute half-life temperature is 170°C or lower, curing can be sufficiently advanced when the adhesive layer A is heated from room temperature at a temperature increase rate of 10°C / min, and η ＊ （ａ） to 5.0 x 10 ３ (d) The one-minute half-life temperature of the organic peroxide is more preferably 140° C. or higher. (d) The one-minute half-life temperature of the organic peroxide is more preferably 160° C. or lower, and particularly preferably 150° C. or lower.

[0037] The blending amount of (d) organic peroxide is preferably 0.2 parts by mass or more, more preferably 0.2 to 3.0 parts by mass, and particularly preferably 0.2 to 1.0 parts by mass, relative to 100 parts by mass of (a) acrylic polymer. When the blending amount of (d) organic peroxide is within this range, it can function sufficiently as a thermal polymerization initiator and can maintain a melt viscosity η within a specific numerical range. ＊ （ａ） The physical properties required in the present invention, including those of the various preferred embodiments, can be more easily achieved.

[0038] The adhesive layer A may contain only a part of the above-mentioned (a) acrylic polymer, (b) isocyanate crosslinking agent, (c) polyfunctional acrylate, and (d) organic peroxide, but preferably contains all of them. In this case, a preferred formulation of the adhesive layer A can be one containing, relative to 100 parts by mass of the (a) acrylic polymer, 0.01 to 8 parts by mass of (b) isocyanate crosslinking agent, 10 to 100 parts by mass of (c) polyfunctional acrylate, and 0.2 to 3.0 parts by mass of (d) organic peroxide.

[0039] The adhesive layer A may contain, if desired, various thermal crosslinking agents such as melamine compounds and epoxy compounds, and known additives such as release agents, plasticizers, resins, surfactants, waxes, and particulate fillers.

[0040] The release agent may generally be any agent that exhibits a release effect and is not particularly limited. Examples include hydrocarbon compounds, silicone compounds, fluorine compounds, and polyethylene waxes, carnauba wax, montanic acid, and stearic acid, which are known as release agents for plastic materials. Among these, silicone and fluorine compounds are preferred, with silicone and fluorine compounds having functional groups that can crosslink with curable adhesives being more preferred. Silicone compounds, in particular, have excellent heat resistance, eliminating concerns about scorching even after treatment involving heating at 200°C or higher. Upon peeling, they are unevenly distributed near the adherend interface, facilitating peeling. Since silicone compounds have functional groups that can crosslink with the curable adhesive, they chemically react with the curable adhesive upon light irradiation or heating, remaining in the curable adhesive, thereby reducing silicone compound contamination of the adherend. The inclusion of a silicone compound also prevents adhesive residue on semiconductor chips. Other examples of release agents include plasticizers. Plasticizers are generally not particularly limited as long as they reduce the adhesive strength of the adhesive to the adherend. Examples of plasticizers include trimellitic acid ester, pyromellitic acid ester, phthalic acid ester, and adipic acid ester.

[0041] The amount of release agent added is not particularly limited, but is appropriately determined so as to obtain a release effect. On the other hand, the amount added is controlled so as not to be excessive so as not to significantly impair the adhesive function of the adhesive layer A. For example, it is desirable to adjust the amount added according to the peel force, with an amount of usually 0.1 to 5 parts by mass, preferably 0.1 to 3 parts by mass, and more preferably 0.1 to 1 part by mass, relative to 100 parts by mass of the entire adhesive layer A.

[0042] Furthermore, when a plasticizer is added, it is desirable to adjust the amount depending on the peel strength, and the amount to be added can be typically about 5 to 50 parts by mass, preferably 10 to 50 parts by mass, and more preferably about 20 to 40 parts by mass, relative to 100 parts by mass of the entire pressure-sensitive adhesive layer A. In the present embodiment, these release agents and plasticizers can be used alone or in combination of two or more.

[0043] The thickness of the adhesive layer A is not particularly limited, but a preferred lower limit is 5 μm and a preferred upper limit is 250 μm, and a more preferred lower limit is 10 μm and a more preferred upper limit is 200 μm for the thickness of the adhesive layer A. When the thickness of the adhesive layer A is within this range, the unevenness of the wafer can be absorbed and the adhesive layer can be temporarily fixed to the support with sufficient strength, and the peel force can be easily adjusted within a preferred range when peeling off the adhesive.

[0044] The adhesive used in the present invention may be composed of only the above-mentioned adhesive layer A, or may have other layers. In either case, only one adhesive layer A may be present, or two or more adhesive layers A may be present. Examples of other layers include adhesive layers other than the adhesive layer A, a base film, and a sacrificial layer that enables peeling in the laser lift-off process. The adhesive layers other than the adhesive layer A are formed at a temperature T （ａ） Melt viscosity η at ＊ （ａ） is 5.0 x 10 ３ ~5.0 x 10 ５ The adhesive layer A differs from the adhesive layer A in that the viscosity is outside the range of Pa s, but other physical properties, components, etc. may or may not have the preferred physical properties, components, etc. described above for the adhesive layer A. The adhesive layer A has a specific viscoelasticity and is therefore excellent in the performance of absorbing irregularities on a wafer or the like, and can therefore be preferably used as an intermediate layer (irregularity absorbing layer).

[0045] In one embodiment of the present invention, a tape including a pressure-sensitive adhesive layer A can be used. Examples of such tapes include a tape having a pressure-sensitive adhesive layer A as an intermediate layer (irregularity-absorbing layer), with a wafer-side pressure-sensitive adhesive layer and a base film sandwiched between the intermediate layer. Furthermore, the tape may be a so-called double-sided pressure-sensitive adhesive tape, which further has a support-side pressure-sensitive adhesive layer on the surface of the base film opposite the wafer-side pressure-sensitive adhesive layer. In this embodiment, the pressure-sensitive adhesive strength on the support side can be appropriately adjusted, allowing the support to be easily removed after wafer processing. The base film can be designed from the perspectives of the mechanical strength and handleability of the entire laminate, which is particularly advantageous from the perspective of optimizing tape performance. While there are no particular limitations on the material of the base film, it is preferable to use a plastic film. Examples include films, sheets, mesh-like sheets, and perforated sheets made of acrylic, olefin, polycarbonate, vinyl chloride, ABS, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), nylon, urethane, polyether ether ketone (PEEK), liquid crystal polymer (LCP), polyimide, etc. From the viewpoint of handling, etc., PET, PEN, or polyimide film is preferred.

[0046] In one embodiment of the present invention, the adhesive layer A may be composed of a liquid adhesive. The adhesive of this embodiment typically comprises only the adhesive layer A, i.e., the adhesive is generally composed of only one or two or more adhesive layers A composed of a liquid adhesive. Here, the liquid adhesive refers to an adhesive that is liquid or semi-liquid at room temperature, and includes, for example, a liquid curable adhesive that is cured by heating or light. According to the liquid adhesive of this embodiment, the liquid adhesive is applied to either or both of the wafer and the support by spin coating or the like to form a laminate of wafer / adhesive or adhesive / support, and then the two adhesive layers are bonded together to produce a laminate of support / adhesive / wafer.

[0047] Wafer: There are no particular limitations on the wafer used to form the wafer / adhesive / support laminate in step (a), and any wafer commonly used in semiconductor manufacturing processes can be used. Wafers that require careful handling during processing due to their thinness and fragility, and therefore require temporary fixation, are preferred. Here, the thinness and fragility of the wafer are assumed to be due to, for example, cases in which the wafer becomes thin during processing, causing handling problems. The adhesive layer A is used to temporarily fix such wafers to the support. Examples of cases in which thin wafers are handled include cases in which a relatively thick wafer is thinned during processing, and cases in which the thinned wafer is further processed. The thickness of the thinned wafer is typically 1 to 200 μm. For example, in a case in which a semiconductor wafer with functional layer processing completed is temporarily fixed to the support so that the functional layer faces the support, the opposite side (backside) of the functional layer is thin-ground, ion implantation, annealing, and electrode formation are performed on the backside, and the semiconductor wafer during processing corresponds to the wafer. As described above, the wafers temporarily fixed using the adhesive material include those whose state changes during the process.

[0048] As described above, there is no particular limitation on the wafer to be temporarily fixed using the adhesive layer A, but more specific examples thereof include, for example, semiconductor wafers, silicon wafers, compound semiconductor wafers such as SiC, AlSb, AlAs, AlN, AlP, BN, BP, BAs, GaSb, GaAs, GaN, GaP, InSb, InAs, InN, or InP, quartz wafers, sapphire, glass, mold wafers, etc. The silicon wafers and compound semiconductor wafers may be doped.

[0049] Electrical / electronic functional layers may be formed on or within the wafer. Examples of suitable functional layers include electronic circuits, capacitors, transistors, resistors, electrodes, optical elements, and MEMS, but other microdevices may also be used. The surfaces of these functional layers may have structures, typically electrodes, formed from one or more of the following materials: silicon, polysilicon, silicon dioxide, (oxy)silicon nitride, metals (e.g., copper, aluminum, gold, tungsten, and tantalum), low-k dielectrics, polymer dielectrics, and various metal nitrides and metal silicides. The surface of the wafer on which the functional layer is formed (the functional layer surface) may have raised structures such as solder bumps, metal posts, and pillars. The wafer surface may also be covered with an oxide or nitride film for the formation of the functional layer or for protection of the functional layer. The wafer surface may also be covered with a passivation film for wafer protection. The adhesive has excellent unevenness absorption properties and is therefore suitable for temporarily fixing wafers having uneven surfaces, more specifically, it can be particularly suitably used for temporarily fixing wafers having unevenness of 5 μm or more on the surface to be bonded to the adhesive. The excellent unevenness absorption properties of the adhesive are more pronounced when the unevenness of the wafer surface to be bonded to the adhesive is 8 μm or more, and are particularly beneficial when it is 10 μm or more.

[0050] The method for producing a wafer of the present invention includes the steps of: (a) bonding a wafer, an adhesive, and a support to form a laminate consisting of wafer / adhesive / support; if desired, (b) curing the adhesive by heating or ultraviolet irradiation; (c) subjecting the wafer to a heat treatment, mechanical processing treatment, chemical treatment, physical treatment, laser processing treatment, and / or film formation treatment; (d) removing the support from the laminate; and (e) removing the adhesive from the laminate consisting of wafer / adhesive.

[0051] Step (a) Step (a) is a step of forming a laminate consisting of a wafer / adhesive / support. That is, it is a step of laminating in order to temporarily fix the wafer and the support via the adhesive. The temperature T of Layer A at the time of forming the laminate consisting of the wafer / adhesive / support in step (a) is （ａ） The lamination temperature in step (a) is preferably 100 to 300° C., and more preferably 120 to 250° C. The lamination pressure in step (a) is preferably 0.05 to 1.0 MPa, and more preferably 0.1 to 0.5 MPa. The lamination time in step (a) is preferably 10 to 600 seconds, and more preferably 60 to 300 seconds.

[0052] The adhesive material used in step (a) and its preferred form are as described above. Furthermore, instead of the adhesive material of the embodiment having the above-mentioned (d) organic peroxide, an adhesive material having a photocurable adhesive component that crosslinks and cures upon light irradiation may be used. As described above, the adhesive material may be in the form of a tape, or a liquid adhesive material may be used.

[0053] Examples of the photocurable adhesive component include a photocurable adhesive component containing a monomer, oligomer, or polymer such as acrylic, epoxy, urethane acrylate, epoxy acrylate, silicone acrylate, or polyester acrylate as a curing component, and containing a photopolymerization initiator.

[0054] Examples of the photopolymerization initiator include those that are activated by irradiation with light having a wavelength of 250 to 800 nm. Examples of such photopolymerization initiators include acetophenone derivative compounds such as methoxyacetophenone, benzoin ether compounds such as benzoin propyl ether and benzoin isobutyl ether, ketal derivative compounds such as benzyl dimethyl ketal and acetophenone diethyl ketal, phosphine oxide derivative compounds, bis(η5-cyclopentadienyl)titanocene derivative compounds, benzophenone, Michler's ketone, chlorothioxanthone, todecylthioxanthone, dimethylthioxanthone, diethylthioxanthone, α-hydroxycyclohexylphenyl ketone, and 2-hydroxymethylphenylpropane. These photopolymerization initiators may be used alone or in combination of two or more.

[0055] Wafer As the wafer used to form a laminate consisting of wafer / adhesive / support in the step (a), the wafers described above can be used.

[0056] Support The support used to form a laminate consisting of a wafer / adhesive / support in step (a) preferably has sufficient strength and rigidity and excellent heat resistance and chemical resistance. By using such a support, even if the wafer is thin-ground in a subsequent step, it becomes possible to handle the wafer stably and to subject the wafer to multiple and / or diverse processes without causing bending, etc. For example, a wafer on which an electronic circuit is formed can be subjected to various processes required to manufacture an electronic device having a structure in which semiconductor chips are stacked, such as TSV connection.

[0057] Materials preferably used for the support include silicon, sapphire, quartz, metals (e.g., aluminum, copper, steel), and various glasses and ceramics. The support may be composed of a single material, or may be composed of multiple materials, or may include other materials deposited on the substrate. For example, a silicon wafer may have a vapor-deposited layer of silicon nitride or the like. The support may also be surface-treated, such as by providing a silicone layer. In particular, glass is preferably used for the support, as it allows visualization of the bonding state, etc.

[0058] Depending on the temperature of the process to which the laminate is subjected, the support may be made of plastic. For example, a sheet made of plastic such as polyimide, acrylic, polyolefin, polycarbonate, vinyl chloride, ABS, polyethylene terephthalate (PET), nylon, or urethane can be preferably used as the support. Polyimide can be used because it has a certain degree of heat resistance.

[0059] To obtain uniformity in the thickness of the wafer after grinding, etc., it is desirable for the thickness of the support to be uniform. For example, to thin a silicon wafer to 50 μm or less and maintain the uniformity at ±10% or less, the variation in the thickness of the support should be kept to ±2 μm or less. There are no particular restrictions on the thickness of the support, but from the viewpoint of effectively preventing wafer curvature, it is preferably 300 μm or more, and more preferably 500 μm or more. From the viewpoint of reducing the total weight during handling or reducing the stress required for mechanical peeling, it is preferably 1500 μm or less, and more preferably 1000 μm or less.

[0060] In the step (a), a laminate comprising a support / adhesive / wafer can be obtained. By curing the adhesive in the laminate in the step (b) described below, the laminate has sufficient strength and rigidity, and the wafer can be subjected to various semiconductor manufacturing processes while preventing bending and breakage.

[0061] As a method for forming the laminate, the support, the adhesive material, and the wafer can be laminated in this order. The order of lamination is not particularly limited, and these layers may be laminated at once or sequentially.

[0062] When the adhesive material is supplied as a liquid curable adhesive material or the like, the liquid curable adhesive material or the like is applied to either or both of the wafer and the support by spin coating or the like to form a laminate of wafer / adhesive or adhesive material / support, and then the adhesive layers of both are bonded together under reduced pressure, thereby making it possible to prepare a laminate consisting of support / adhesive / wafer.

[0063] When the adhesive material is supplied as a solid film, the solid film is attached to either the wafer or the support, and then the other is attached under reduced pressure, thereby producing a laminate consisting of the support / adhesive material / wafer.

[0064] Step (b) The step (b), which may be adopted as desired in the above embodiment, is a step of curing the adhesive material by heating or ultraviolet irradiation, and is a step of curing the adhesive material in the laminate obtained in step (a).

[0065] The curable adhesive component that has been crosslinked and cured by irradiation with light or heating has dramatically improved chemical resistance, and can prevent the adhesive from dissolving in a chemical solution, even when, for example, a backside of a wafer is treated with a chemical solution in a wafer processing step. Furthermore, the crosslinked and cured curable adhesive component has an increased elastic modulus, and therefore is less likely to exhibit increased adhesion even at high temperatures, making it relatively easy to peel off.

[0066] For example, when a photocurable adhesive component that crosslinks and cures by irradiation with light is used, the photocurable adhesive component contains a polymer having an unsaturated double bond such as a vinyl group in a side chain and a photopolymerization initiator that is activated at a wavelength of 250 to 800 nm, and the photocurable adhesive component is preferably irradiated with light at an illuminance of 5 mW or more, more preferably 10 mW or more, even more preferably 20 mW or more, and particularly preferably 50 mW or more. ２It is preferable to irradiate with an integrated light amount of 500 mJ / cm or more. ２ Above, 10000mJ / cm ２ It is more preferable to irradiate with an integrated light amount of 500 mJ / cm or less. ２ Above, 7500mJ / cm ２ It is more preferable to irradiate with an integrated light amount of 1000 mJ / cm or less. ２ Above, 5000mJ / cm ２ It is particularly preferable to irradiate with the following integrated light amount.

[0067] Furthermore, for example, when a pressure-sensitive adhesive containing a polymer having an unsaturated double bond such as a vinyl group in a side chain and a thermal polymerization initiator that is activated by heating at about 50 to 200°C is used as the thermosetting pressure-sensitive adhesive component that crosslinks and cures when heated, the thermosetting pressure-sensitive adhesive component can be crosslinked and cured by heating at a temperature of about 50 to 200°C for 5 to 40 minutes.

[0068] In one embodiment of the present invention, in step (b), the adhesive material may be cured by heating at 120 to 160°C for 5 to 40 minutes. When a thermosetting temporary fixing material is used, the adhesive material can be designed to be sufficiently cured by heating at 120°C or higher for 5 minutes or longer. In addition, from the viewpoint of productivity, it is preferable to set the heating conditions to 160°C or lower and / or 40 minutes or shorter. From the viewpoint of stably carrying out subsequent processes by curing, the melt viscosity η of the adhesive material after curing in step (b) is preferably 0.05 to 0.15. ＊ （ｂ） is 1.0 x 10 5 ~1.0 x 10 ６ Pa s, and preferably 2.0 × 10 ５ ~8.0 x 10 ５ It is more preferable that the viscosity is Pa·s.

[0069] Step (c) is a step of subjecting the wafer to a heat treatment, a mechanical processing treatment, a chemical treatment, a physical treatment, a laser processing treatment, and / or a film formation treatment. The stack formed through steps (a) and (b) can be subjected to at least one wafer treatment selected from a heat treatment (including a treatment involving heat generation; the same applies hereinafter), a mechanical processing treatment, a chemical treatment, a physical treatment, a laser processing treatment, and a film formation treatment. In addition, the stack formed through steps (a) and (b) can also be subjected to processing required for TSV processing or for forming a structure in which TSV-processed semiconductor chips are stacked.

[0070] Examples of the heat treatment include, but are not limited to, thermal curing of the resin composition, heat drying of the resin composition, baking of the resin composition, reflow, resin sealing, and the like.

[0071] The above-mentioned machining processes typically include polishing, grinding, drilling, and cutting of the wafer, but are not limited to these and also include singulation. When grinding or polishing a wafer having electrodes formed on its surface, the surface on which the electrodes are not formed (back surface) is ground or polished. The thickness of the wafer after back surface grinding and polishing varies depending on the electronic device in which the obtained electronic device is used, but is usually set to 1 μm or more and 200 μm or less, preferably 5 μm or more and 100 μm or less, and more preferably 5 μm or more and 50 μm or less. This allows the obtained electronic device to be made thinner, thereby realizing the miniaturization of electronic devices using such electronic devices.

[0072] In this embodiment, when grinding or polishing a wafer, the wafer is laminated to a rigid support via an adhesive material, which allows the wafer to be ground or polished with greater processing accuracy, and after grinding or polishing, the wafer can be subjected to further processing steps or the wafer and the adhesive material can be easily separated without damaging the wafer.

[0073] The chemical treatment is, for example, a polishing treatment such as CMP, a treatment using an acid, an alkali, or an organic solvent, and examples thereof include plating treatments such as electrolytic plating and electroless plating, wet etching treatments using hydrofluoric acid, an aqueous solution of tetramethylammonium hydroxide (TMAH), or the like, a resist stripping process using N-methyl-2-pyrrolidone, monoethanolamine, DMSO, or the like, and a cleaning process using concentrated sulfuric acid, aqueous ammonia, aqueous hydrogen peroxide, or the like, but is not limited to these.

[0074] Examples of the physical treatment include, but are not limited to, plasma treatment, ion implantation, and laser annealing.

[0075] Examples of the laser processing include, but are not limited to, annealing, via processing, circuit formation processing by direct writing, and pre-processing for separation from the support.

[0076] Examples of the film formation process include, but are not limited to, coating processes such as spin coating, inkjet printing, and screen printing, sputtering, vapor deposition, etching, chemical vapor deposition (CVD), physical vapor deposition (PVD), resist coating / patterning, heat lamination of a resin composition film, and back metal.

[0077] As described above, in this embodiment, although the wafer is subjected to heat treatment, mechanical processing treatment, chemical treatment, physical treatment, laser processing treatment, and film formation treatment in the wafer processing step, sufficient adhesive strength is maintained during the wafer processing, and the occurrence of voids is effectively suppressed. Furthermore, after the wafer processing step is completed, the wafer can be peeled from the adhesive material without being damaged in the step of peeling the wafer from the laminate.

[0078] Furthermore, after the treatment of step (c), chip bonding, wire bonding, flip chip bonding, surface activation direct bonding, etc. may be performed. Furthermore, a dicing tape may be attached to the treated surface (preferably the ground surface) of the wafer. By attaching the dicing tape in advance, dicing can be performed quickly after peeling off the support and the adhesive material.

[0079] Step (d) Step (d) is a step of removing the support from the laminate. In step (d), the method for removing the support from the laminate is not particularly limited, but it is preferably performed by laser peeling or mechanical peeling, since it is advantageous in terms of cost because it can simplify the equipment. In addition, a treatment before peeling may be performed in advance, and a method such as swelling or dissolution of the adhesive material with a solvent may be appropriately adopted as the treatment before peeling.

[0080] Step (e) Step (e) is a step of removing the adhesive from a laminate consisting of a wafer / adhesive. Because the support has been removed from the laminate via step (d), the adhesive can be separated from the wafer without applying excessive stress to the wafer, thereby minimizing the risk of damaging functional layers, etc. formed on the wafer. There are no particular limitations on the method for removing the adhesive, but considering the ease of peeling of the adhesive, for example, a peeling tape can be attached to the adhesive, and the adhesive can be peeled from the wafer together with the peeling tape, which is also advantageous in terms of cost because no special equipment, etc. is required.

[0081] According to the wafer manufacturing method of the present invention, the wafer can be stably processed and subjected to subsequent processes to manufacture a final product. When a functional layer is formed on the wafer, the final product can be manufactured by carrying out processes such as dicing, bonding, packaging, and sealing that are commonly used in the manufacture of electronic devices such as semiconductor devices.

[0082] The present invention will be specifically described below, but the present invention is not limited in any way by the following examples.

[0083] Details of the materials used in the examples and comparative examples are as follows.

[0084] Separator: A silicone release-treated PET film (polyethylene terephthalate film, manufactured by Mitsui Chemicals Tohcello, Inc., product name: T15, thickness: 38 μm) was used. Substrate film: The non-corona-treated side of a PEN film (polyethylene naphthalate film, manufactured by Toyobo Co., Ltd., product name: Teonex Q83C, thickness: 50 μm, corona-treated on one side) was corona-treated to obtain a double-sided corona-treated substrate film. Primer-coated substrate film: An aqueous urethane resin liquid (manufactured by DIC Corporation, product name: Hydran AP-40N) was diluted with distilled water to obtain a coating liquid (solids concentration: 10%). This coating liquid was applied to the above substrate film (PEN film) using a wire bar and dried at 130°C for 5 minutes. Similarly, a primer was laid on the back side to obtain a primer-coated substrate film.

[0085] Resin (a) Acrylic Polymer for Forming Tacky Adhesive Layer - Acrylic Resin Solution N 49 parts by mass of ethyl acrylate, 20 parts by mass of 2-ethylhexyl acrylate, 21 parts by mass of methyl acrylate, 10 parts by mass of glycidyl methacrylate, and 0.5 parts by mass of a benzoyl peroxide-based polymerization initiator were reacted in a solvent consisting of 65 parts by mass of toluene and 50 parts by mass of ethyl acetate at 80°C for 10 hours. After completion of the reaction, the resulting solution was cooled, and 25 parts by mass of xylene, 5 parts by mass of acrylic acid, and 0.5 parts by mass of tetradecyldimethylbenzylammonium chloride were added to the cooled solution. The reaction was continued for 32 hours at 85°C while blowing in air, yielding Acrylic Resin Solution N. The solids concentration was 39%.

[0086] Chemicals for forming adhesive layer (c) Polyfunctional acrylates Polyfunctional acrylate M309 manufactured by Toagosei Co., Ltd., trade name: Aronix M309 Polyfunctional acrylate M402 manufactured by Toagosei Co., Ltd., trade name: Aronix M402 (d) Organic peroxides Organic peroxide Perbutyl O manufactured by NOF Corporation, trade name: Perbutyl O Chemical name: t-Butyl peroxy-2-ethylhexanoate 1-minute half-life temperature: 134°C Organic peroxide Perkadox 12XL25 manufactured by Kayaku Nouryon Co., Ltd., trade name: Perkadox 12XL25 Chemical name: 2,2-Di(4,4-di(t-butylperoxy)cyclohexyl)propane 1-minute half-life temperature: 145°C Organic peroxide Perbutyl P manufactured by NOF Corporation, trade name: Perbutyl P Chemical name: α,α'-Di(t-butylperoxy)diisopropylbenzene 1-minute half-life temperature: 175°C (b) Isocyanate crosslinking agent Multifunctional isocyanate D-170N manufactured by Mitsui Chemicals, Inc., trade name: Takenate D-170N Mold release agent BYK-UV3500 Mold release agent manufactured by BYK Japan Co., Ltd., trade name: BYK-UV3500

[0087] Example 1 Preparation of a Sample for Viscoelasticity Evaluation Acrylic resin solution N (100 parts by mass as solids), polyfunctional acrylate M309 (30 parts by mass as solids), organic peroxide Perbutyl O (0.5 parts by mass as solids), polyfunctional isocyanate D-170N (0.1 parts by mass as solids), and ethyl acetate were mixed to obtain a coating liquid for an intermediate layer (solids concentration: 35%). This coating liquid was applied to the release surface of a separator using an applicator and dried in a hot air oven at 100°C for 10 minutes to form a 50 μm-thick adhesive layer. Two such adhesive layers were formed, and these adhesive layers were bonded together to prepare an adhesive layer (100 μm) with separators on both sides. This was then heat-aged in a hot air oven at 50°C for 5 days. Subsequently, the separator on one side was peeled off, and the two adhesive layers were repeatedly bonded together to obtain an intermediate layer (500 μm) for viscoelasticity evaluation with separators on both sides.

[0088] Preparation of Adhesive Tape (Laminate) The adhesive tape (laminate) of Example 1 was prepared as follows. Coating of Adhesive Intermediate Layer: A coating liquid having the same formulation as that used to prepare the viscoelasticity evaluation sample was applied to the release surface of a separator using an applicator and dried in a hot air oven at 100°C for 10 minutes to form a 40 μm-thick adhesive layer. This was then bonded to the primer-attached substrate film side to obtain a separator / intermediate layer (40 μm) / primer-attached substrate. Similarly, the intermediate layer coating liquid was applied to the release surface of the separator using an applicator and dried in a hot air oven at 100°C for 10 minutes to form a 40 μm-thick adhesive layer. This was then bonded to the intermediate layer side of the previously prepared separator / intermediate layer (40 μm) / primer-attached substrate from which the separator had been peeled (intermediate layer (40 μm) / primer-attached substrate), to obtain a separator / intermediate layer (80 μm) / primer-attached substrate. Adhesive Surface Layer Coating: Acrylic resin solution N (100 parts by weight in terms of solids), multifunctional acrylate M309 (30 parts by weight in terms of solids), organic peroxide Perbutyl O (0.5 parts by weight in terms of solids), multifunctional isocyanate D-170N (5.68 parts by weight in terms of solids), and ethyl acetate were mixed to obtain a surface layer coating solution (solids concentration: 30%). This coating solution was applied to the release surface of a separator using an applicator and dried in a hot air oven at 100°C for 10 minutes to form a 10 μm-thick adhesive layer. This was then bonded to the separator / intermediate layer (80 μm) / primer-attached substrate film from which the separator had been peeled, to obtain a laminate consisting of separator / surface layer (10 μm) / intermediate layer (80 μm) / primer-attached substrate film. Coating of adhesive carrier side and preparation of double-sided adhesive tape Acrylic resin solution N (100 parts by mass as solid content), polyfunctional acrylate M402 (50 parts by mass as solid content), organic peroxide Perkadox 12XL25 (0.5 parts by mass as solid content), polyfunctional isocyanate D-170N (2.84 parts by mass as solid content), release agent BYK-UV3500 (2 parts by mass as solid content), and ethyl acetate were mixed to obtain a carrier side coating liquid (solid content concentration: 35%).This coating liquid was applied to the release surface of a separator using an applicator and dried in a hot air oven at 100°C for 10 minutes to form a 25 μm thick adhesive layer. Subsequently, this was bonded to the primer-attached substrate film side of the previous separator / intermediate layer (80 μm) / primer-attached substrate film to obtain a laminate consisting of separator / surface layer (10 μm) / intermediate layer (80 μm) / primer-attached substrate film / carrier side (25 μm) / separator. Subsequently, this laminate was heat-aged in an oven at 50°C for 5 days to obtain a double-sided pressure-sensitive adhesive tape.

[0089] Evaluation Evaluation of Viscoelasticity of Pressure-Sensitive Adhesive The sample for viscoelasticity evaluation prepared above (separators on both sides removed, thickness: 500 μm, diameter: 25 mmφ) was heated from room temperature to 250°C at a heating rate of 10°C / min under a nitrogen atmosphere using a viscoelasticity measuring device (TA Instruments, ARES, measurement mode: parallel plate) to measure the temperature dispersion of melt viscoelasticity (frequency: 1 Hz, strain: 0.2%). The obtained values ​​of melt viscosity η at 70°C, 100°C, 130°C, and 200°C were read. The results are shown in Table 1. The melt viscosity η at 70°C was measured by the 70°C lamination (T （ａ） = 70 ° C) ＊ （ａ） The melt viscosity η at 100°C is （ａ） = 100 ° C) ＊ （ａ） The melt viscosity η at 130°C is （ａ） = 130 ° C) ＊ （ａ） The minimum value of the melt viscosity is called the "minimum melt viscosity η ＊ ｍｉｎ " and the temperature at which the minimum melt viscosity is obtained is defined as "the temperature T ｍｉｎ The values ​​of tan δ measured at 70° C., 100° C. and 130° C. are also shown in Table 1.

[0090] Void Evaluation After Laminating Patterned Wafer The following glass substrate and evaluation coupon were used for the void evaluation after laminating the patterned wafer. Glass Substrate: A glass substrate (manufactured by Nippon Electric Glass Co., Ltd., product name: OA-11, size: 150 mm x 150 mm, thickness: 0.7 mm) cut into a size of 75 mm x 75 mm was used. Evaluation Coupon (Patterned Wafer): A thermal oxide film was formed on an 8-inch silicon wafer, followed by a titanium film and an aluminum film. The titanium film and aluminum film were etched to form scribe lines intended for 10 mm x 10 mm chips. Subsequently, a photosensitive polyimide film (10 μm) was formed, and then openings were made on the scribe lines and in the electrode-intended areas to obtain an evaluation uneven pattern wafer. This evaluation uneven wafer was then diced into individual pieces measuring 30 mm x 30 mm to obtain evaluation coupons (unevenness: 10 μm).

[0091] The separator on the carrier side of the pressure-sensitive adhesive tape (laminate) prepared above was peeled off, and the adhesive tape was attached to a glass substrate using a roller (23°C). After peeling the separator from the obtained separator / adhesive / glass substrate, the adhesive / glass substrate and the evaluation coupon were laminated under vacuum using a vacuum laminator (manufactured by The Japan Steel Works, Ltd., MVLP-600 / 700-II) at a temperature (T （ａ） The samples were laminated at a temperature (lamination temperature) of 70°C, 100°C, or 130°C) under 0.8 MPa for 60 seconds to obtain a laminate of evaluation coupon / double-sided adhesive tape / glass substrate. This was visually observed from the glass substrate side, and samples with voids were evaluated as "voids present" and samples without voids were evaluated as "voids absent." The results are shown in Table 1. The melt viscosity of the intermediate layer at the temperature (lamination temperature) at the time of forming the evaluation coupon / double-sided adhesive tape / glass substrate laminate was determined to be within the range of the present invention (5.0 × 10 ３ ~5.0 x 10 ５ In the case of lamination at 130°C, which is within the range of the temperature (Pa·s), voids were effectively suppressed.

[0092] (Examples 2 to 4 and Comparative Example 1) Samples for viscoelasticity evaluation were prepared and viscoelasticity was evaluated in the same manner as in Example 1, except that the adhesive formulation was as shown in Table 1. Furthermore, adhesive tapes (laminates) were prepared and void evaluation was performed after lamination to a patterned wafer in the same manner as in Example 1, except that the adhesive formulation was as shown in Table 1. The results are shown in Table 1. When the melt viscosity of the intermediate layer at the temperature at the time of forming the evaluation coupon / double-sided adhesive tape / glass substrate laminate (lamination temperature) was within the range of the conditions of the present invention (5.0 × 10 ３ ~5.0 x 10 ５ In the lamination at 130°C in each example, which was within the range of the temperature (Pa·s), voids were effectively suppressed.

[0093]

[0094] The wafer manufacturing method of the present invention makes it possible to perform numerous and / or diverse processes on wafers with high productivity and yield without damaging electronic components such as functional layers formed on the wafer, and greatly contributes to improving the productivity of electronic components such as electronic devices.Therefore, it has high applicability in various fields of industries such as the electronic component industry, including the semiconductor process industry, the electrical and electronics industry that uses electronic components, the transportation machinery industry, the information and communications industry, and the precision equipment industry.

Claims

1. A method for manufacturing a wafer, comprising the steps of: (a) bonding a wafer, an adhesive, and a support to form a laminate consisting of wafer / adhesive / support; (c) subjecting the wafer to a heat treatment, a mechanical processing treatment, a chemical treatment, a physical treatment, a laser processing treatment, and / or a film formation treatment; (d) removing the support from the laminate; and (e) removing the adhesive from the wafer / adhesive laminate, wherein the temperature T at the time of formation of the laminate when the temperature is increased from room temperature in step (a) at a rate of 10° C. / min is （ａ） The melt viscosity η of at least one layer A in the adhesive material ＊ （ａ） is 5.0 x 10 ３ ~5.0 x 10 ５ A method for manufacturing a wafer, 2. The wafer manufacturing method according to claim 1, further comprising the step of: (b) curing the adhesive by heating or irradiating with ultraviolet light.

3. A wafer manufacturing method according to claim 1 or 2, wherein the loss coefficient tan δ of said layer A at 130° C. is 0.01 to 0.

40.

4. The temperature T of the layer A in step (a) （ａ） The method for producing a wafer according to claim 1 or 2, wherein the heating temperature is 100 to 300° C.

5. The method for producing a wafer according to claim 1 or 2, wherein the bonding pressure in step (a) is 0.05 to 1.0 MPa and the bonding time is 10 to 600 seconds.

6. The temperature T of the layer A in step (a) （ａ） The melt viscosity η of the layer A at a temperature 30° C. lower than ＊ （ａ） ' is 1.0 x 10 2 ~1.0 x 10 3 3. The method for producing a wafer according to claim 1, wherein the surface roughness is Pa·s.

7. The melt viscosity η of the layer A after curing in step (b) ＊ （ｂ） is 1.0 x 10 5 ~1.0 x 10 ６ 3. The method for producing a wafer according to claim 1, wherein the surface roughness is Pa·s.

8. The method for producing a wafer according to claim 1 or 2, wherein the unevenness of the surface of the wafer on the side to be bonded to the adhesive material is 5 μm or more.

9. A method for manufacturing an electronic device, comprising the step of manufacturing a wafer by the method for manufacturing a wafer according to claim 1 or 2.

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