Wafer Processing Method

Abstract

Provided is a wafer treatment method in which a wafer is treated in a laminate state with the wafer being fixed to a support by means of a temporary fastening member, and with which it is possible to separate the wafer from the laminate stably by using a relatively simple process such as a mechanical separation. This wafer treatment method comprises: a step (1) for laminating a support (A), a temporary fastening member (B), and a wafer (C) placed on a surface of a temporary fastening member (B) at the side opposite to the support (A) side; a step (2) for subjecting the wafer (C) to at least one treatment selecting from a heat treatment, a mechanical machining treatment, a wet treatment, and a laser machining treatment; and a step (3) for detaching, from a laminate (D) including thus treated wafer (C), the wafer (C). The ratio P2 / P1 of a 10° peel strength P2 between the adhesive layer (B) and the wafer (C) to a 10° peel strength P1 between the support (A) and the adhesive layer (B), measured while the angles formed between the mutually separated layers are maintained at 10°, is 1.1 or more.

Description

[Technical field]

[0001] The present invention relates to a wafer processing method in which a wafer is processed or otherwise treated in a state in which the wafer is fixed to a support via a temporary fixing material, and more specifically, to a processing method in which the introduction of a support improves the handleability of the wafer, making it possible to use the wafer in a wide variety of processing processes, while at the same time enabling the wafer to be stably separated by a relatively simple process such as mechanical peeling. [Background technology]

[0002] In the semiconductor manufacturing process, temporary fixing is often necessary or desirable for wafer processing due to the thinness and fragility of the wafer. For example, thin grinding of wafers on which functional layers for semiconductor devices are formed is widely used for the high integration of semiconductor devices. However, when grinding to an extremely thin thickness, the wafer cannot be supported by tape alone, and it has been proposed to temporarily fix the wafer to a hard carrier (support) via a temporary fixing material before processing after thin grinding. The semiconductor manufacturing process using such a support is called a wafer support system. Methods proposed for peeling the support after processing include a method that utilizes gas generation from the temporary bonding material (see, for example, Patent Document 1), a peeling method that uses a laser, a peeling method in which the resin in the temporary bonding material is melted and the carrier is slid off, and a method in which the carrier is lifted from one end and peeled off (mechanical peeling). The mechanical peeling method is a method with excellent cost benefits because the equipment is relatively simple. However, in principle, the mechanical peeling method applies a peeling force at least to the wafer / temporary bonding material interface and the temporary bonding material / support interface, so it is not necessarily easy to achieve stable peeling at the desired interface. If peeling occurs at an unintended interface (e.g., the wafer / temporary bonding material interface), problems such as damage to the support or electronic components may occur when the support is peeled off. On the other hand, the adhesive strength at unintended interfaces can be increased to prevent peeling from unintended interfaces during mechanical peeling. However, if the adhesive strength is increased too much, it becomes difficult to peel the temporary bonding material from the wafer, for example. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] International Publication No. 2014 / 024861 A1 Brochure Summary of the Invention [Problem to be solved by the invention]

[0004] In view of the above technical background, an object of the present invention is to provide a processing method for wafers in a stacked state in which the wafers are fixed to a support via a temporary fixing material, and which can stably separate the wafers from the stack by a relatively simple process such as mechanical peeling. [Means for solving the problem]

[0005] As a result of extensive investigations, the inventors have discovered that in a wafer processing method in which processing is performed in the state of a laminate in which the wafer is fixed to a support via a temporary bonding material, when the peel strength between the support / temporary bonding material and the peel strength between the temporary bonding material / wafer, measured under specific conditions, satisfy specific conditions, the wafer can be stably separated from the laminate by a relatively simple process such as mechanical peeling, and have completed the present invention. That is, the present invention provides: [1] A step (1) of stacking a support (A), a temporary bonding material (B), and a wafer (C) located on the side of the temporary bonding material (B) opposite to the support (A); A step (2) of subjecting the wafer (C) to at least one treatment selected from a heat treatment, a mechanical processing treatment, a wet processing treatment, and a laser processing treatment; A step (3) of separating the wafer (C) from the laminate (D) having the treated wafer (C); A method for processing a wafer, comprising: the ratio of the 10° peel strength P1 between the support (A) and the temporary fixing material (B) to the 10° peel strength P2 between the temporary fixing material (B) and the wafer (C), P2 / P1, measured while maintaining the angle between the peeled layers at 10°, is 1.1 or more; Regarding.

[0006] Below, [2] to

[14] are each a preferred aspect or embodiment of the present invention. [2] The method for treating a wafer according to [1], wherein the peel strength P1 is 10 N / 25 mm or less. [3] The method for treating a wafer according to [1] or [2], wherein the adhesive layer of the temporary bonding material (B) in contact with the support (A) and the adhesive layer in contact with the wafer (C) have different compositions. [4] The method for treating a wafer according to any one of [1] to [3], wherein separation of the wafer (C) from the laminate (D) is achieved by separating the support (A) from the temporary bonding material (B) and then removing the temporary bonding material (B) remaining on the wafer (C). [5] The method for treating a wafer according to [4], wherein the method for separating the temporary bonding material (B) and the support (A) is mechanical peeling. [6] The method for treating a wafer according to any one of [1] to [5], wherein the temporary fixing material (B) contains a curable adhesive component. [7] The method for treating a wafer according to any one of [1] to [5], wherein the temporary bonding material (B) contains a release agent. [8] The method for treating a wafer according to any one of [1] to [7], wherein the temporary bonding material (B) is a base film (B0) having a pressure-sensitive adhesive material laminated on both sides thereof. [9] The method for treating a wafer according to any one of [1] to [8], wherein an electrode is formed on the wafer (C).

[10] The method for treating a wafer according to any one of [1] to [9], wherein in step (2), a surface of the wafer (C) on which no electrode is formed is ground.

[11] The method for treating a wafer according to

[10] , wherein the thickness of the wafer (C) after grinding is 1 μm or more and 200 μm or less.

[12] A method for manufacturing an electronic device, comprising carrying out the wafer processing method according to any one of [1] to

[11] .

[13] The method for producing an electronic device according to

[12] , wherein the electronic device has a structure in which semiconductor chips are stacked.

[14] A laminate (D) in which a support (A), a temporary fixing material (B), and a wafer (C) located on a side of the temporary fixing material (B) opposite to the support (A), A laminate in which the ratio of the 10° peel strength P1 between the support (A) and the temporary fixing material (B) to the 10° peel strength P2 between the temporary fixing material (B) and the wafer (C), P2 / P1, is 1.1 or more, measured while maintaining the angle between the peeled layers at 10°. Effect of the Invention

[0007] According to the wafer processing method of the present invention, the handleability of thin or fragile wafers is improved, and the wafers can be stably processed in a wide range of processing processes. In addition, unintended peeling at the interface is effectively suppressed, and the processed wafers can be stably separated and removed by a relatively simple and low-cost process such as mechanical peeling. This makes it 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, greatly contributing to improving the productivity of electronic components such as electronic devices. [Brief description of the drawings]

[0008] [Figure 1] FIG. 2 is a schematic diagram illustrating mechanical peeling in one embodiment of the present invention. [Diagram 2] FIG. 1 is a schematic diagram illustrating separation of a support (A) from a laminate (D) in one embodiment of the present invention, where (a) shows a preferred separation form, and (b) and (c) show unpreferred separation forms. [Diagram 3] FIG. 1 is a schematic diagram for explaining a method for measuring a 10° peel strength specified in the present invention, in which (a) shows a case where a measurement sample for 10° peel strength P1 is used, in which a tacky adhesive layer (B1) on the side in contact with a support (A) is laminated onto a base film (B0), (b) shows a case where a measurement sample for 10° peel strength P2 is used, in which a tacky adhesive layer (B2) on the side in contact with a wafer (C) is laminated onto a base film (B0), (c) shows a case where a measurement sample for temporary fixing material (B) not having a base film (B0) is prepared by laminating a polyimide film, and the 10° peel strength P1 is measured, and (d) shows a case where a measurement sample for temporary fixing material (B) not having a base film (B0) is prepared by laminating a polyimide film, and the 10° peel strength P2 is measured. [Figure 4] FIG. 2 is a schematic diagram showing a method for evaluating the removability of a temporary bonding material (B) from a wafer (C) in one embodiment of the present invention. [Diagram 5] FIG. 2 is a schematic diagram showing a laminate (D) in one embodiment of the present invention. [Figure 6] FIG. 2 is a schematic diagram showing a laminate (D) according to another embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The present invention relates to A step (1) of stacking a support (A), a temporary bonding material (B), and a wafer (C) located on the side of the temporary bonding material (B) opposite to the support (A); A step (2) of subjecting the wafer (C) to at least one treatment selected from a heat treatment, a mechanical processing treatment, a wet processing treatment, and a laser processing treatment; A step (3) of separating the wafer (C) from the laminate (D) having the treated wafer (C); A method for processing a wafer, comprising: the ratio of the 10° peel strength P1 between the support (A) and the temporary fixing material (B) to the 10° peel strength P2 between the temporary fixing material (B) and the wafer (C), P2 / P1, measured while maintaining the angle between the peeled layers at 10°, is 1.1 or more; It is. That is, in the processing method of the present invention, a support (A) and a temporary bonding material (B) serving as a temporary bonding material are used in processing a wafer (C).

[0010] Support (A) The support (A) is preferably one having sufficient strength and rigidity, and excellent heat resistance and chemical resistance. By using such a support (A), even if the wafer (C) is thin-ground, the wafer (C) can be stably handled, and the wafer (C) can be subjected to a large number and / or a wide variety of processes without bending or the like. For example, the wafer (C) on which an electronic circuit is formed can be subjected to various processes required for manufacturing an electronic device having a structure in which semiconductor chips are stacked, such as TSV connection. Materials preferably used for the support (A) include silicon, sapphire, quartz, metals (e.g., aluminum, copper, steel), and various glasses and ceramics. The support (A) may be composed of a single material, but may also be composed of multiple materials, and may contain other materials deposited on the substrate. For example, the support may have a vapor deposition layer such as silicon nitride on a silicon wafer. In order to adjust the 10° peel strength P1 between the temporary fixing material (B) and the adhesive, the adhesive may be surface-treated, for example by providing a silicone layer.

[0011] Depending on the temperature of the process in which the laminate (D) is subjected, the support (A) may be made of a plastic. For example, a sheet made of a plastic such as polyimide, acrylic, polyolefin, polycarbonate, vinyl chloride, ABS, polyethylene terephthalate (PET), nylon, or urethane can be preferably used as the support (A). It is particularly preferable to use polyimide because it has a certain degree of heat resistance.

[0012] It is desirable for the thickness of the support (A) to be uniform in order to obtain uniformity in the thickness of the wafer (C) after grinding, etc. For example, in order to thin a silicon wafer to 50 μm or less with a uniformity of ±10% or less, the variation in the thickness of the support (A) should be suppressed to ±2 μm or less. The thickness of the support (A) is not particularly limited, but from the viewpoint of effectively preventing the warping of the wafer (C), it is preferably 300 μm or more, and particularly preferably 500 μm or more, and from the viewpoint of suppressing the total weight during handling or reducing the stress required for mechanical peeling, it is preferably 1500 μm or less, and particularly preferably 1000 μm or less.

[0013] Temporary fixing material (B) The temporary fixing material (B) is used to fix the wafer (C) to the support (A). It is preferable that the temporary fixing material (B) can be easily peeled off from the support (A) and the wafer (C). Therefore, it is preferable that the temporary fixing material (B) has a sufficient adhesive strength to fix the wafer (C) to the support (A) but has a sufficiently low adhesive strength so that it can be peeled off.

[0014] It is preferable to use a pressure-sensitive adhesive material for the temporary fixing material (B), and examples of pressure-sensitive adhesive materials used in such an embodiment include rubber-based, acrylic-based, epoxy-based, urethane-based, allyl-based, silicone-based, fluorine-based, and polyimide-based pressure-sensitive adhesive materials, etc. Among these, acrylic-based or silicone-based pressure-sensitive adhesive materials are preferred because they are heat-resistant and easy to adjust the adhesive strength and bonding strength.

[0015] The adhesive material may be either a curable adhesive material or a non-curable adhesive material. However, it is preferable to use a curable adhesive material, since curing it before heat treatment makes it less likely that voids will be generated during heat treatment in the manufacturing process, and the increased adhesion due to high temperatures during heat treatment can be suppressed, making it easy to peel off without leaving any glue residue.

[0016] Examples of the curable adhesive include photocurable adhesives that are crosslinked and cured by irradiation with light, and thermosetting adhesives that are crosslinked and cured by heating. Examples of the photocurable adhesive material and thermosetting adhesive material include photocurable adhesive material and thermosetting adhesive material that contain a monomer, oligomer or polymer such as acrylic, epoxy, urethane acrylate, epoxy acrylate, silicone acrylate or polyester acrylate as a curing component and contain a photopolymerization initiator or a thermal polymerization initiator.

[0017] Among the above, the acrylic adhesive 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 a functional group-containing (meth)acrylic polymer), and 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 a functional group-containing unsaturated compound).

[0018] The functional group-containing (meth)acrylic polymer is obtained by copolymerizing, in a conventional manner, an acrylic acid alkyl ester and / or a methacrylic acid alkyl ester, the carbon number of which in the alkyl group is usually in the range of 2 to 18, with a functional group-containing monomer and, if necessary, with another modifying monomer copolymerizable therewith. The weight-average molecular weight of the functional group-containing (meth)acrylic polymer is usually about 200,000 to 2,000,000.

[0019] 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.

[0020] Examples of the other copolymerizable modifying monomers include various monomers used in general (meth)acrylic polymers, such as vinyl acetate, acrylonitrile, and styrene.

[0021] As the functional group-containing unsaturated compound to be reacted with the functional group-containing (meth)acrylic polymer, the same as the functional group-containing monomer described above can be used according to 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.

[0022] The photopolymerization initiator may be 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.

[0023] The thermal polymerization initiator may be one that decomposes by heat to generate active radicals that initiate polymerization and curing. Specific examples of the thermal polymerization initiator include hexanoic acid t-butylperoxy-2-ethyl, 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, monocarboxylate t-hexylperoxyisopropyl, t-butylperoxyacetate, 2,2-bis-( t-butylperoxy)butane, n-butyl 4,4-bis-(t-butylperoxy)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, diisopropylbenzene hydroperoxide, and the like. Among these thermal polymerization initiators, 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 P, Perbutyl C, Perhexine 25B, Percumyl P (all manufactured by NOF Corp.), Perkadox 12XL25 (manufactured by Noury ​​Chemical Co., Ltd.), etc. These thermal polymerization initiators may be used alone or in combination of two or more kinds.

[0024] The oligomer or monomer as the curing component generally has a molecular weight of 10,000 or less, and the number of radically polymerizable unsaturated bonds in the molecule is 1 to 40. From the viewpoint of three-dimensional reticulation, the number of radically polymerizable unsaturated bonds is preferably 2 or more.

[0025] 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 above-mentioned methacrylates. Other examples include 1,4-butylene glycol diacrylate, 1,6-hexanediol diacrylate, polyethylene glycol diacrylate, commercially available oligoester acrylates, urethane acrylates, and the above-mentioned methacrylates. These polyfunctional oligomers or monomers may be used alone or in combination of two or more.

[0026] The temporary fixing material (B) may contain, as desired, known additives such as an acrylic polymer having no unsaturated double bond, various thermal crosslinking agents such as an isocyanate compound, a melamine compound, an epoxy compound, etc., a release agent, a plasticizer, a resin, a surfactant, a wax, a particulate filler, etc.

[0027] In the temporary bonding material (B), it is preferable to use a release agent from the viewpoint of adjusting the peel strength with the support (A) and / or the wafer (C). The release agent is not particularly limited as long as it generally exhibits a release effect. For example, hydrocarbon compounds, silicone compounds, fluorine compounds, polyethylene wax, carnauba wax, montanic acid, stearic acid, etc., which are known as release agents for plastic materials, can be mentioned. Among them, silicone and fluorine compounds are preferred, and silicone and fluorine compounds having a functional group capable of crosslinking with the curable adhesive are more preferred. In particular, silicone compounds have excellent heat resistance, so they prevent the adhesive from burning even after treatment involving heating at 200°C or higher, and when peeled off, they bleed out to the interface with the adherend, making it easy to peel off. Since the silicone compound has a functional group that can crosslink with the curing adhesive, it chemically reacts with the curing adhesive when irradiated with light or heated, and is incorporated into the curing adhesive, so the silicone compound does not adhere to the adherend and contaminate it. In addition, the incorporation of a silicone compound also has the effect of preventing glue from remaining on the semiconductor chip. Other examples of the release agent include plasticizers. The plasticizer is not particularly limited as long as it generally reduces the adhesive strength of the adhesive material to the adherend. Examples of the plasticizer include trimellitic acid esters, pyromellitic acid esters, phthalic acid esters, and adipic acid esters.

[0028] The amount of the 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 temporary fixing material (B). For example, it is desirable to adjust the amount of addition according to the peeling force, usually 0.1 to 5 parts by mass, preferably 0.1 to 3 parts by mass, and more preferably about 0.1 to 1 part by mass, based on 100 parts by mass of the total temporary fixing material (B).

[0029] When a plasticizer is added, it is desirable to adjust the amount of addition according to the peel strength, usually about 5 to 50 parts by mass, preferably about 10 to 50 parts by mass, and more preferably about 20 to 40 parts by mass. In this embodiment, these release agents can be used alone or in combination.

[0030] The thickness of the temporary fixing material (B) is not particularly limited, but the preferred lower limit is 5 μm and the preferred upper limit is 250 μm, and the more preferred lower limit of the thickness of the temporary fixing material (B) is 10 μm and the more preferred upper limit is 200 μm. If the thickness of the temporary fixing material (B) is within this range, the unevenness of the wafer (C) can be absorbed and the temporary fixing to the support (A) can be performed with sufficient strength, and the peeling force can be easily adjusted to a preferred range when peeling off the temporary fixing material (B).

[0031] The temporary fixing material (B) may be a single layer or a laminate of multiple layers. In the case of a laminate of multiple layers, it is preferable that the layers on the wafer (C) side and the support (A) side are layers (adhesive layers) having adhesive properties. In this case, one adhesive layer (B1) can be configured to have an appropriate peel strength between the support (A), and the other adhesive layer (B2) can be configured to have an appropriate peel strength between the support (A). In this case, it is preferable that the adhesive layer (B1) in contact with the support (A) and the adhesive layer (B2) in contact with the wafer (C) have different compositions. In this case, the adhesive layer (B1) and the adhesive layer (B2) may have a layered structure in the general sense, in which the composition changes discontinuously at the interface, but may also have a so-called gradient composition, in which the composition changes continuously. The adhesive layer (B1) in contact with the support (A) and the adhesive layer (B2) in contact with the wafer (C) may be directly laminated, but it is preferable that they are laminated on both sides of the base film (B0) to form a so-called double-sided adhesive tape. In this embodiment, the adhesive layer (B1) can be designed from the viewpoint of optimizing the peel strength between the support (A), the adhesive layer (B2) can be designed from the viewpoint of optimizing the peel strength between the wafer (C), and the base film (B0) can be designed from the viewpoint of the mechanical strength and handleability of the entire temporary fixing material (B) and the entire laminate (D), and therefore, this is particularly advantageous from the viewpoint of optimizing the performance of the temporary fixing material (B). An example of a laminate (D) using a temporary fixing material (B) consisting of a pressure-sensitive adhesive layer (B1), a base film (B0), and a pressure-sensitive adhesive layer (B2) is shown in Fig. 5. In the figure, 11 indicates a support (A), 20 indicates the pressure-sensitive adhesive layer (B1) on the support (A) side, 19 indicates the base film (B0), 18 indicates the pressure-sensitive adhesive layer (B2) on the wafer (C) side, and 13 indicates the wafer (C). The material of the base film (B0) is not particularly limited, but it is preferable to use a plastic film, and examples of such films include films, sheets, sheets having a mesh structure, and sheets with holes, 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.

[0032] Wafer (C) There is no particular limitation on the wafer (C) to be processed by the method of the present invention, and any wafer that can be processed in step (2) of the present invention can be used. In particular, the method of the present invention is preferably used for processing wafers that require careful handling due to their thinness and fragility, and therefore require temporary fixing (temporary fixation). Here, the thinness and fragility of the wafer are often brought about in steps (1) and / or (2) described below. For example, the method of the present invention is preferably used for processing wafers that temporarily become thin during processing, causing problems in handling. Examples of cases where a wafer becomes temporarily thin include a case where a thin wafer is processed starting from a thin wafer, a case where a relatively thick wafer is thinned during a process, and a case where the thin wafer is further processed. The thickness of the temporarily thinned wafer (C) is usually 1 to 200 μm. For example, in a case where a semiconductor wafer on which processing of a functional layer has been completed is temporarily fixed to a carrier so that the functional layer faces the carrier, the opposite side (back side) of the functional layer is thin-ground, ions are implanted on the back side, annealing is performed, and electrodes are formed, and the semiconductor wafer during the process corresponds to wafer (C). As described above, the wafer (C) to be processed in the present invention includes those whose state changes during the process. As described above, the wafer (C) to be processed by the present invention is not particularly limited. More specific examples thereof include semiconductor wafers such as 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, and mold wafers. The silicon wafer or compound semiconductor wafer may be doped.

[0033] An electric / electronic functional layer may be formed on or in the wafer (C). Suitable examples of the functional layer include electronic circuits, capacitors, transistors, resistors, electrodes, optical elements, MEMS, etc., but may also be other microdevices. The surfaces of these functional layers may have structures, typically electrodes, formed from one or more of the following materials: silicon, polysilicon, silicon dioxide, silicon (oxy)nitride, metals (e.g., copper, aluminum, gold, tungsten, tantalum), low-k dielectrics, polymer dielectrics, and various metal nitrides and metal silicides. The surface of the wafer (C) on which the functional layers are formed (functional layer surface) may also have raised structures such as solder bumps and metal posts and pillars.

[0034] Process (1) The wafer processing method of the present invention includes a step (1) of stacking the above-mentioned support (A), temporary bonding material (B), and a wafer (C) located on the side of the temporary bonding material (B) opposite to the support (A). An example of the state after step (1) is shown in Fig. 6. In the figure, 11 indicates a support (A), 12 indicates a temporary bonding material (B), and 13 indicates a wafer (C). By fixing the wafer (C) to the support plate (A) via the temporary fixing material (B), the wafer (C) can be easily handled when it is processed in the subsequent step (2), and bending or damage can be prevented.

[0035] The order in which the support (A), the temporary bonding material (B), and the wafer (C) are laminated is not particularly limited, and these layers may be laminated at once or sequentially. When the temporary fixing material (B) is supplied as a liquid curable adhesive material or the like, the liquid curable adhesive material or the like can be applied onto either one or both of the wafer (C) and the support (A) by spin coating or the like to form the temporary fixing material (B) or a precursor of the temporary fixing material (B), and then a laminate can be created. When the temporary fixing material (B) or a precursor of the temporary fixing material (B) is supplied as a solid film, the adhesive strength to the support is usually set lower than that to the wafer side. Therefore, from the viewpoint of preventing peeling during handling, it is preferable to first adhere the film onto the wafer (C) and then laminate the support (A). Furthermore, in the case where the film is attached at normal pressure and only the formation of the laminate is performed under reduced pressure, it is preferable to first attach the film-like temporary fixing material onto the support (A) and then attach this to the wafer (C) in order to improve the absorption of the unevenness of the wafer.

[0036] When the temporary fixing material (B) or a precursor of the temporary fixing material (B) contains a curable adhesive component, the temporary fixing material (B) may be obtained by irradiating the curable adhesive component with light or heating in step (1) to crosslink and cure the curable adhesive component through adhesive curing. The curable adhesive component crosslinked and cured by irradiation with light or heat has a dramatically improved chemical resistance, and can suppress the adhesive from dissolving in a chemical solution, even if a chemical solution is applied to the back surface of the wafer (C) in step (2). In addition, the crosslinked and cured curable adhesive component has an increased elastic modulus, so that adhesion is less likely to increase even at high temperatures, and peeling is relatively easy. Thus, in this embodiment, even though the wafer (C) is subjected to heat treatment, mechanical processing, and / or wet processing in step (2), sufficient adhesive strength is maintained during the wafer (C) processing, and after completion of the wafer (C) processing step, the wafer (C) can be peeled off from the temporary fixing material (B) in step (3) without being damaged or leaving any adhesive residue.

[0037] For example, when a photocurable adhesive component that is crosslinked and cured by the above-mentioned light irradiation is used, the adhesive component is preferably irradiated with an illuminance of 5 mW or more, more preferably irradiated with an illuminance of 10 mW or more, even more preferably irradiated with an illuminance of 20 mW or more, and particularly preferably irradiated with an illuminance of 50 mW or more. In addition, the adhesive component is preferably irradiated with an integrated illuminance of 300 mJ or more, more preferably irradiated with an integrated illuminance of 500 mJ or more and 10000 mJ or less, even more preferably irradiated with an integrated illuminance of 500 mJ or more and 7500 mJ or less, and particularly preferably irradiated with an integrated illuminance of 1000 mJ or more and 5000 mJ or less.

[0038] In addition, 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 in which the temporary fixing material (B) or a precursor of the temporary fixing material (B) is crosslinked and cured by the above-mentioned heating, the above-mentioned thermosetting pressure-sensitive adhesive component can be crosslinked and cured by heating at a temperature of about 50 to 200°C for 10 to 60 minutes.

[0039] When the precursor of the temporary fixing material (B) is cured to form the temporary fixing material (B) as described above, the temporary fixing material (B) may be laminated with the support (A) or the wafer (C) after curing, or may be cured after lamination, or may be laminated in a semi-cured state and then finally cured.

[0040] Process (2) The wafer processing method of the present invention next includes a step (2) of subjecting the wafer (C) after the step (1) to at least one treatment selected from a heat treatment, a mechanical processing treatment, a wet processing treatment, and a laser processing treatment. The above step (2) includes TSV processing and processing necessary for forming a structure in which TSV-processed semiconductor chips are stacked. Examples of the heat treatment (including treatment accompanied by heat generation; the same applies hereinafter) include sputtering, deposition, etching, chemical vapor deposition (CVD), physical vapor deposition (PVD), resist coating / patterning, heat lamination of a resin composition film, heat curing of a resin composition, heat drying of a resin composition, baking of a resin composition, reflow, resin sealing, plasma treatment, chip bonding, wire bonding, flip chip bonding, surface activation direct bonding, and the like, but are not limited to these. The wafer processing method of the present invention can be suitably adapted to temperatures of 100° C., particularly 150° C. or higher, during the above-mentioned steps.

[0041] The machining process is typically a polishing, grinding, drilling, cutting process of the wafer, but is not limited to this, and also includes singulation and the like. When grinding or polishing a wafer (C) having electrodes formed on its surface, the surface on which no electrodes are formed (back surface) is ground or polished. The thickness of the wafer (C) after such back surface grinding and polishing varies depending on the electronic device in which the resulting 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 resulting electronic device to be made thinner, and the electronic device using the electronic device to be made smaller.

[0042] In this embodiment, when grinding and polishing the wafer (C), the wafer (C) is laminated to a rigid support (A) via a temporary fixing material (B), so that the wafer (C) can be ground, etc. with higher processing accuracy. After the grinding, etc., the wafer (C) can be subjected to further processing steps or easily separated from the support (A) and the temporary fixing material (B) without damaging the wafer (C).

[0043] The wet processing is a coating process such as spin coating, inkjet, or screen printing, a polishing process such as CMP, or a process using an acid, an alkali, or an organic solvent. Examples of the wet processing include plating processes such as electrolytic plating and electroless plating, wet etching processes using hydrofluoric acid, an aqueous tetramethylammonium hydroxide solution (TMAH), or the like, resist stripping processes using N-methyl-2-pyrrolidone, monoethanolamine, DMSO, or the like, and cleaning processes using concentrated sulfuric acid, aqueous ammonia, aqueous hydrogen peroxide, or the like, but are not limited to these. The above-mentioned laser treatment includes, but is not limited to, annealing, via processing, circuit formation processing by direct writing, and pre-treatment for separation from a support.

[0044] In the wafer processing method of the present invention, a dicing tape may be applied to the processed surface (preferably the ground surface) of the wafer after the above processing prior to step (3) described below. By applying the dicing tape in advance, dicing can be performed promptly after peeling off the support (A) and the temporary fixing material (B) in step (3).

[0045] In the present invention, the support (A) is separated from the temporary bonding material (B) in the step (3), but a treatment prior to the separation may be carried out in advance in the step (2). Specifically, methods such as laser treatment, swelling or dissolution of the temporary fixing material (B) with a solvent before mechanical peeling can be appropriately adopted, but it is preferable not to carry out these treatments because it is advantageous in terms of cost since the equipment can be simplified. In this specification, the laminate having the wafer (C) that has been subjected to the step (2) is also referred to as a laminate (D).

[0046] Process (3) The wafer processing method of the present invention next comprises a step (3) of separating the processed wafer (C) from the laminate (D). The separation of the wafer (C) from the laminate (D) is preferably achieved by separating the support (A) from the laminate (D) and then removing the temporary fixing material (B) remaining on the wafer (C). In this embodiment, when removing the temporary fixing material (B) remaining on the wafer (C), the normally rigid support (A) has already been separated from the laminate (D), so that the wafer (C) can be separated from the temporary fixing material (B) without applying excessive stress to the wafer (C), thereby minimizing the risk of damaging the functional layer formed on the wafer (C). There are no particular limitations on the method for separating the support (A) from the temporary bonding material (B), but it is preferable to use mechanical peeling. Both the separation between the support (A) and the temporary bonding material (B) and the separation between the temporary bonding material (B) and the wafer (C) may be performed by mechanical peeling, or a method other than mechanical peeling may be used for one of them.

[0047] In the wafer processing method of the present invention, since the peel strength ratio P2 / P1 is 1.1 or more, peeling between the support (A) and the temporary fixing material (B) is relatively easy, and therefore the support (A) can be stably peeled from the laminate (D) over the entire surface of the laminate (D) by a relatively simple process such as mechanical peeling. At this time, peeling at an unintended interface, i.e., between the temporary fixing material (B) and the wafer (C), is effectively suppressed, so the risk of damaging the functional layer formed on the wafer (C) is limited.

[0048] In the laminate (D) composed of the support (A) / temporary bonding material (B) / wafer (C) separated in step (3), the ratio of the 10° peel strength P1 between the support (A) / temporary bonding material (B) and the 10° peel strength P2 between the temporary bonding material (B) / wafer (C), measured while maintaining the angle between the peeled layers at 10°, P2 / P1, is 1.1 or more. The 10° peel strength P1 between the support (A) / temporary bonding material (B) and the 10° peel strength P2 between the temporary bonding material (B) / wafer (C) are measured values ​​after a history equivalent to that of step (2) described later. For example, when a thermal history of 150 to 200°C is applied in step (2), the values ​​are values ​​after the thermal history is applied. According to the wafer processing method of the present invention, since the peel strength ratio P2 / P1 is 1.1 or more, the support (A) can be stably peeled off from the temporary fixing material (B) over the entire surface of the laminate (D) by a relatively simple process such as mechanical peeling. At this time, peeling at the unintended interface, i.e., between the temporary bonding material (B) and the wafer (C), is effectively suppressed, so the risk of damaging the functional layer formed on the wafer (C) is limited. In addition, the phenomenon in which some of the temporary bonding material (B) remains on the support (A) or some of the temporary bonding material (B) on the wafer (C) is lost is also effectively suppressed, so the risk of the wafer (C) or support (A) being damaged due to uneven stress is also limited.

[0049] The 10° peel strength P1 between the support (A) and the temporary fixing material (B) and the 10° peel strength P2 between the temporary fixing material (B) and the wafer (C) are the force (N / mm) per width of the peeled portion required to proceed with peeling while maintaining the angle between the peeled layers (support (A) and the temporary fixing material (B), or the temporary fixing material (B) and the wafer (C)) at 10°. That is, the 10° peel strength P1 between support (A) and temporary fixing material (B) and the 10° peel strength P2 between temporary fixing material (B) and wafer (C) can be determined by progressing the peel between 11 support (A) and 12 temporary fixing material (B) or between 12 temporary fixing material (B) and 13 wafer (C) in the state shown in FIG. 3 or a state equivalent thereto, measuring the force required for peeling, and dividing this by the width of the peeled portion. More specifically, they can be measured by the following method.

[0050] Since the support (A) and wafer (C) are usually rigid or brittle, it is usually difficult to maintain the angle between the peeled layers at 10° when the laminate (D) of support (A) / temporary fixing material (B) / wafer (C) is formed, therefore, when measuring the 10° peel strength P1 between support (A) / temporary fixing material (B), a sample for measuring 10° peel strength P1 without wafer (C) can be used (Figs. 3(a) and (c)), and when measuring the 10° peel strength P2 between temporary fixing material (B) / wafer (C), a sample for measuring 10° peel strength P2 without support (A) can be used (Figs. 3(b) and (d)). In the former case, when the temporary fixing material (B) has a base film (B0), a sample for measuring 10° peel strength P1 is constructed from the support (A) and the temporary fixing material (B) having the base film (B0) and measurement is performed (Figure 3(a)). When the temporary fixing material (B) does not have a base film and is only an adhesive layer, a polyimide film or the like is backed onto the adhesive layer to construct a sample for measuring 10° peel strength P1 and measurement is performed (Figure 3(c)). In the latter case, when the temporary fixing material (B) has a base film (B0), a sample for measuring the 10° peel strength P2 is composed of the temporary fixing material (B) having the base film (B0) and the wafer (C) and the measurement is performed (Figure 3(b)). When the temporary fixing material (B) does not have a base film and is only an adhesive layer, a polyimide film or the like is backed on the adhesive layer to form a sample for measuring the 10° peel strength P2 and the measurement is performed (Figure 3(d)).

[0051] The peel strength ratio P2 / P1 is preferably 1.1 or more, and particularly preferably 1.3 or more. There is no particular upper limit to the above peel strength ratio P2 / P1, but from the viewpoint of properly peeling the wafer (C) from the temporary fixing material (B), it is desirable that the peel strength P2 between the temporary fixing material (B) / wafer (C) is not excessively large, and from the viewpoint of stably carrying out the processing in step (2), particularly the machining processing, it is desirable that the 10° peel strength P1 between the support (A) / temporary fixing material (B) is not too small, so the above peel strength ratio P2 / P1 is preferably 30 or less, more preferably 15 or less, and particularly preferably 7 or less.

[0052] In step (3), from the viewpoint of stably peeling the support (A) from the temporary fixing material (B) over the entire surface of the laminate (D) in a relatively simple process such as mechanical peeling and without applying excessive stress to the wafer (C), it is preferable that the 10° peel strength P1 between the support (A) / temporary fixing material (B) is 10 N / 25 mm or less. The 10° peel strength P1 between the support (A) and the temporary fixing material (B) is more preferably 8 N / 25 mm or less, and particularly preferably 7 N / 25 mm or less. In order to stably perform the treatment in step (2), particularly the machining treatment, the 10° peel strength P1 between the support (A) and the temporary fixing material (B) is preferably 1 N / 25 mm or more, and more preferably 2 N / 25 mm or more.

[0053] The separation of the temporary bonding material (B) and the wafer (C) in step (3) is preferably achieved by separating the support (A) from the laminate (D) and then removing the temporary bonding material (B) remaining on the wafer (C). From this perspective, the 10° peel strength P2 between the temporary bonding material (B) / wafer (C) is preferably 30 N / 25 mm or less, and more preferably 20 N / 25 mm or less. From the viewpoint of stably carrying out the processing in step (2), particularly the machining processing, the 10° peel strength P2 between the temporary fixing material (B) / wafer (C) is preferably 2 N / 25 mm or more, and more preferably 3 N / 25 mm or more.

[0054] There are no particular limitations on the means for adjusting the 10° peel strength P1, 10° peel strength P2, and peel strength ratio P2 / P1, but they can be appropriately increased or decreased by, for example, means conventionally used in the art. More specifically, they can be appropriately increased or decreased by the composition and manufacturing process of each layer, the manufacturing process of the laminate (D), etc. For example, the 10° peel strength P1 and the 10° peel strength P2 can be increased by increasing the amount of adhesive material components such as adhesives and pressure sensitive adhesives used in the temporary fixing material (B), and the 10° peel strength P1 and the 10° peel strength P2 can be decreased by adding a release agent to the temporary fixing material (B).

[0055] The mechanical peeling method in this embodiment is not particularly limited, and peeling can be performed using a commercially available device, etc. For example, peeling is preferably performed by the method shown in FIG. In this method, the wafer (C) side 13 of the laminate (D) is fixed onto a chuck table (not shown) via a dicing tape 14, and then the support (A) 11 is held by a holding mechanism (not shown). The remover 16 is slid into the interface between the support 11 (A) and the temporary fixing material 12 (B) and an upward force is applied to the end of the support 11 (A), forming a peeling interface between the support 11 (A) and the temporary fixing material 12 (B) that will trigger peeling (Figure 1 (b)). The support (A) 11 is warped by applying pressure using the holding mechanism, expanding the peeling interface and allowing the peeling to proceed (Figure 1(c)). When the peeling interface spreads and a peeling interface is formed over the entire surface between 11 support (A) and 12 temporary fixing material (B), 11 support (A) is peeled off from 12 temporary fixing material (B). Examples of commercially available devices of this type include XBC Gen2 manufactured by SUSS, EVG805 manufactured by EVG, and TWH-SR series manufactured by Tatsumo Corporation.

[0056] At this time, according to the present invention, peeling at the interface between 12 temporary fixing material (B) and 13 wafer (C), which is not intended to peel off at this stage, is effectively suppressed, so that the functional layers etc. formed on 13 wafer (C) are effectively protected by 12 temporary fixing material (B), and the risk of damage to these functional layers etc. can be minimized (Figure 2(a)).

[0057] In the conventional technology, before the peeling between the support 11 (A) and the temporary fixing material 12 (B), peeling may occur at the interface between the temporary fixing material 12 (B) and the wafer 13 (C), which is not intended to be peeled off at this stage (FIG. 2(b)). As a result, there was a risk that the electronic circuits formed on the wafer 13 (C) would be damaged during the peeling, or would be damaged in a subsequent process that still required protection by the temporary fixing material 12 (B). In the conventional technology, the support (A) could not be completely peeled off because some of the temporary fixing material (B) (12) remained on the support (A) (11) or some of the temporary fixing material (B) (12) on the wafer (C) (13) was missing (Fig. 2(c)). As a result, uneven stress was applied to the wafer (C) (13) and the support (A) (11), which could cause them to break. When the temporary bonding material (B) remains on the wafer (C), it may be removed by dissolving it in a solvent. The present invention solves these problems of the prior art, prevents unintended interface peeling and uneven peeling, or at least significantly reduces the frequency of such occurrences, thereby making it possible to perform multiple and / or diverse processes on the wafer with high productivity and yield without damaging the functional layers formed on the wafer.

[0058] The wafer processed by the wafer processing method of the present invention can be subjected to further steps to manufacture a final product. When a functional layer is formed on the wafer, the wafer can be subjected to further steps such as dicing, bonding, packaging, sealing, etc., which are generally used in the manufacture of electronic devices such as semiconductor devices, to manufacture the final product. EXAMPLES

[0059] The present invention will be specifically described below. Note that the present invention is not limited in any way by the following examples.

[0060] The physical properties and characteristics in the examples and comparative examples were evaluated by the following methods. (1) Mechanical peelability The prepared laminate (D) was subjected to a prescribed heat history shown in Table 1, and then fixed at room temperature with the 13 wafer (C) side down on the 14 dicing tape attached to the 15 ring frame, and the 14 dicing tape was fixed by vacuum chucking (Fig. 1(a)). In order to peel the interface between the 11 support (A) and the 12 temporary fixing material (B), as shown in Fig. 1, the 16 remover was slid into the interface between the 11 support (A) and the 12 temporary fixing material (B), and an upward force of typically up to about 120 N was applied to the end of the 11 support (A), forming a peeling interface that would trigger peeling between the 11 support (A) and the 12 temporary fixing material (B) (Fig. 1(b)). Next, pressure was applied to the formed peel interface to expand the peel interface, thereby peeling off the support (A) 11 (Figure 1(c)). The peelability was evaluated according to the following criteria. ◯: The intended support (A) / temporary bonding material (B) interface was peeled off over the entire surface, and no damage occurred to the wafer (C). ×: Unintended peeling occurred at the interface between the temporary bonding material (B) and the wafer (C).

[0061] (2) Removability of temporary bonding material (B) from wafer (C) After the mechanical peelability evaluation described above, the 13 wafer (C) / 12 temporary fixing material (B) laminate was fixed to the 14 dicing tape attached to the 15 ring frame, and the 17 adhesive tape was attached to the entire surface of the 12 temporary fixing material (B). The 14 dicing tape was fixed with a vacuum chuck, and the 12 temporary fixing material (B) was peeled off at a peel angle of 90° and a peel speed of 5 mm / s. The peelability was evaluated according to the following criteria. ◯: The temporary bonding material (B) was completely peeled off from the wafer (C), and no damage occurred to the wafer (C). ×: The temporary bonding material (B) could not be peeled off from the wafer (C).

[0062] (3) 10° peel strength P1 (peel strength between support and temporary fixing material) (3-1) When using a base film (B0) as a temporary bonding material A sample for measuring P1 was prepared by laminating a pressure-sensitive adhesive layer (B1) on the side in contact with a support (A) 20 onto a base film (B0) 19. (3-2) When the base film (B0) is not used as the temporary fixing material A polyimide film 21 (double-sided plasma treatment, thickness 38 μm, manufactured by Toray DuPont Co., Ltd., product name: Kapton (registered trademark) 150EN-A) was prepared, and a sample for measurement P1 was prepared by laminating the same material as the temporary bonding material 12 on top of this. (3-3) Measurement The P1 measurement sample prepared in (3-1) or (3-2) above was cut to 2.5 cm x 5 cm, and the surface of the P1 measurement sample that is the same material as the 20 adhesive layer (B1) or 12 temporary fixing material was attached to the attachment surface of the 11 support (A) cut to 3 cm x 6 cm with a 2 kg roller in one round trip. Next, the prepared support (A) / P1 measurement sample laminate was heated at 140 ° C for 30 minutes as a condition assuming the pretreatment in step (1) in each example and comparative example. Furthermore, after applying a predetermined heat history shown in Table 1 as a condition assuming step (2), the measurement sample was left at 22.5 ± 1 ° C and a relative humidity of 50 ± 10% for one week to cool, and then the peel strength P1 was measured at this temperature and humidity condition using VPA-S (manufactured by Kyowa Interface Science Co., Ltd.) at a pulling speed of 300 mm / min and a peel angle of 10 ° (Figure 3 (a) or (c)).

[0063] (4) 10° peel strength P2 (peel strength between temporary adhesive / wafer) (4-1) When using a base film (B0) as a temporary bonding material A sample for measuring P2 was prepared by laminating a pressure-sensitive adhesive layer (B2) on the side of the substrate film (B0) 19 that contacts the wafer (C) 18. (4-2) When the base film (B0) is not used as the temporary fixing material A polyimide film 21 (double-sided plasma treatment, thickness 38 μm, manufactured by Toray DuPont Co., Ltd., product name: Kapton (registered trademark) 150EN-A) was prepared, and a sample for measuring P2 was created by laminating the same material as the temporary bonding material 12 on top of this. (4-3) Measurement The P2 measurement sample prepared in (4-1) or (4-2) above was cut to 2.5cm x 5cm, and the surface of the P2 measurement sample that is the same material as the 18 adhesive layer (B2) or 12 temporary fixing material was attached to the attachment surface of the wafer (C) cut to 3cm x 6cm by one round trip of a 2kg roller. Next, the prepared wafer (C) / P2 measurement sample laminate was heated at 140°C for 30 minutes as a condition assuming the pretreatment in step (1) in each example and comparative example. Furthermore, after applying a predetermined heat history shown in Table 1 as a condition assuming step (2), the measurement sample was left for one week at 22.5±1°C and a relative humidity of 50±10%, and then cooled. The peel strength P2 was measured at this temperature and humidity condition using VPA-S (manufactured by Kyowa Interface Science Co., Ltd.) at a pulling speed of 300mm / min and a peel angle of 10 degrees (Figure 3(b) or (d)).

[0064] Details of the materials and ingredients used in the examples and comparative examples are as follows. Support (A) and wafer (C) The following glass or Si was used as either the support (A) or the wafer (C): Glass A support substrate for silicon back grinding made of borosilicate heat-resistant glass with an outer diameter of 300 or 200 mm and a thickness of 700 μm was used. ·Si A Si mirror wafer with an outer diameter of 300 or 200 mm and a thickness of 750 μm was used.

[0065] Resin for forming temporary fixing material (B) (Meth)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 as a 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 the reaction was completed, 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, and the reaction was carried out at 85° C. for 32 hours while blowing in air, to obtain a (meth)acrylic resin solution N. ·Silicone modified (meth)acrylic resin solution NS To 270 parts by mass of the above-mentioned (meth)acrylic resin solution N, 0.3 parts by mass of carboxy-modified organopolysiloxane (manufactured by Shin-Etsu Chemical Co., Ltd., product name: X-22-3710) was added and reacted at 60°C for 7 days to obtain a silicone-modified (meth)acrylic resin solution NS. (Meth)acrylic resin solution L A (meth)acrylic adhesive (Bindceram SA591, manufactured by Mitsui Chemicals, Inc.) was used. (Meth)acrylic resin emulsion H Using 0.5 parts by mass of ammonium persulfate as a polymerization initiator, 63 parts by mass of 2-ethylhexyl acrylate, 21 parts by mass of n-butyl acrylate, 9 parts by mass of methyl methacrylate, 3 parts by mass of 2-hydroxyethyl methacrylate, 2 parts by mass of methacrylic acid, 1 part by mass of acrylamide, 1 part by mass of polytetramethylene glycol diacrylate (manufactured by Nippon Oil & Fats Co., Ltd., product name: ADT-250), and 2 parts by mass of an aqueous solution of polyoxyethylene nonylpropenyl phenyl ether ammonium sulfate (manufactured by Daiichi Kogyo Seiyaku Co., Ltd., product name: Aqualon HS-1025) were emulsion-polymerized in deionized water at 70° C. After completion of the polymerization, the pH was adjusted to 7.0 using aqueous ammonia to obtain (meth)acrylic resin emulsion H with a solid content of 56.5% by mass. (Meth)acrylic resin emulsion B Using 0.5 parts by mass of 4,4'-azobis-4-cyanovaleric acid (manufactured by Otsuka Chemical Co., Ltd., product name: ACVA) as a polymerization initiator, 74 parts by mass of n-butyl acrylate, 14 parts by mass of methyl methacrylate, 9 parts by mass of 2-hydroxyethyl methacrylate, 2 parts by mass of methacrylic acid, 1 part by mass of acrylamide, and 3 parts by mass of HS-1025 were emulsion-polymerized in deionized water at 70° C. After completion of the polymerization, the pH was adjusted to 7.0 using aqueous ammonia to obtain (meth)acrylic resin emulsion B with a solid content of 42.5% by mass. (Meth)acrylic resin emulsion A Using 0.65 parts by mass of ACVA as a polymerization initiator, 63 parts by mass of 2-ethylhexyl acrylate, 18 parts by mass of n-butyl acrylate, 12 parts by mass of methyl methacrylate, 3 parts by mass of 2-hydroxyethyl methacrylate, 2 parts by mass of methacrylic acid, 1 part by mass of acrylamide, 1 part by mass of ADT-250, and 2 parts by mass of Aqualon HS-1025 were emulsion-polymerized in deionized water at 70° C. After completion of the polymerization, the pH was adjusted to 7.0 using aqueous ammonia to obtain (meth)acrylic resin emulsion A with a solid content of 42.5% by mass. (Meth)acrylic resin emulsion S Using 0.5 parts by mass of ACVA as a polymerization initiator, 47 parts by mass of n-butyl acrylate, 22 parts by mass of methyl methacrylate, 9 parts by mass of 2-hydroxyethyl methacrylate, 15 parts by mass of methacrylic acid, 8 parts by mass of acrylamide, and 0.2 parts by mass of Aqualon HS-1025 were emulsion-polymerized in deionized water at 70°C to obtain a (meth)acrylic resin emulsion S with a solids content of 40% by mass.

[0066] Base film B 0 ·PEN film A polyethylene naphthalate film (corona-treated on both sides, thickness: 50 μm, manufactured by Toyobo Film Solutions Co., Ltd., Teonex Q83) was used. ·PET film A biaxially oriented polyethylene terephthalate film (corona-treated on both sides, thickness 38 μm, manufactured by Toray Industries, Inc., Lumirror S10) was used.

[0067] Example 1 As the adhesive layer (B1) on the support (A) side, 2.84 parts by mass of HDI isocyanurate (manufactured by Tosoh Corporation, product name: Coronate HX), 50 parts by mass of dipentaerythritol penta / hexaacrylate (manufactured by Toagosei Co., Ltd., product name: Aronix M-402), 2.0 parts by mass of silicone diacrylate (manufactured by Daicel-Allnex Co., Ltd., product name: Ebecryl 350), and 2 parts by mass of Perkadox 12XL25 manufactured by Kayaku Nouryon Co., Ltd. were added to 250 parts by mass of (meth)acrylic resin solution L to obtain a coating liquid for the adhesive layer (B1) on the support (A) side. This coating liquid was applied to a substrate B0 (PEN film) and dried at 100 ° C for 10 minutes to form an adhesive resin layer having a thickness of 25 μm. Next, a silicone release-treated polyethylene terephthalate film (separator) was attached to obtain a laminate of the adhesive layer (B1) / substrate (B0) on the support (A) side with the separator. As the adhesive layer (B2) on the wafer (C) side, a pressure-sensitive adhesive coating liquid was prepared by mixing 42.6 parts by weight of (meth)acrylic resin emulsion H, 57.4 parts by weight of (meth)acrylic resin emulsion B, 0.4 parts by weight of dimethylethanolamine, 3.4 parts by weight of an epoxy compound (manufactured by Nagase Chemtex Corporation, product name: Ex-1610), 13 parts by weight of butyl carbinol, and 20 parts by weight of pure water. This coating liquid was applied to a polyethylene terephthalate film (separator) that had been subjected to a silicone release treatment and dried at 120°C for 3 minutes to form an adhesive resin layer with a thickness of 13 μm. Next, the above-mentioned adhesive layer (B1) / substrate (B0) laminate was laminated to the substrate (B0) side to prepare a pre-heat-treated temporary fixing material (B) precursor having a three-layer structure of adhesive layer (B1) / substrate (B0) / adhesive layer (B2) with a separator. The separators used on both sides of the three-layer structure were peeled off, and the support (A) and wafer (C) shown in Table 1 were laminated using a vacuum laminator and heated at 140°C for 30 minutes to produce a laminate (D) consisting of the support (A) / temporary bonding material (B) / wafer (C) in that order. The mechanical peelability and removability of the laminate (D) were evaluated and the results are shown in Table 1. Separately, a laminate of the adhesive layer (B1) / substrate (B0) and a laminate of the adhesive layer (B2) / substrate (B0) were separately prepared (with the same coating conditions), and the 10° peel strengths P1 and P2 were measured by the above-mentioned method. The measurement results are shown in Table 1.

[0068] Example 2 As the adhesive layer (B1) on the support (A) side, 0.5 parts by mass of HDI isocyanurate (manufactured by Tosoh Corporation, product name: Coronate HX), 12 parts by mass of dipentaerythritol penta / hexaacrylate (manufactured by Toagosei Co., Ltd., product name: Aronix M-400), 1.5 parts by mass of silicone diacrylate (manufactured by Daicel-Allnex Co., Ltd., product name: Ebecryl 350), and 2 parts by mass of Perkadox 12XL25 manufactured by Kayaku Nouryon Co., Ltd. were added to 70 parts by mass of (meth)acrylic resin solution N2 to obtain a coating liquid for the adhesive layer (B1) on the support (A) side. This coating liquid was applied to a polyethylene terephthalate film (separator) treated with silicone release and dried at 100 ° C for 10 minutes to form an adhesive resin layer having a thickness of 100 μm. Next, a substrate B0 (PET film) was attached to obtain a laminate of the adhesive layer (B1) / substrate (B0) on the support (A) side with a separator. Next, the coating liquid for the adhesive layer (B2) on the wafer (C) side in Example 1 was applied to a silicone release-treated polyethylene terephthalate film (separator) and dried at 120°C for 3 minutes to form an adhesive resin layer with a thickness of 6 µm. This was then bonded to the substrate (B0) side of the adhesive layer (B1) / substrate (B0) laminate described above to produce a pre-heat treatment temporary fixing material (B) precursor having a three-layer structure of adhesive layer (B1) / substrate (B0) / adhesive layer (B2) with separator. The separators used on both sides of the three-layer structure were peeled off, and the support (A) and wafer (C) shown in Table 1 were laminated using a vacuum laminator and heated at 140°C for 30 minutes to produce a laminate (D) consisting of the support (A) / temporary bonding material (B) / wafer (C) in that order. The mechanical peelability and removability of the laminate (D) were evaluated and the results are shown in Table 1. Separately, a laminate of the adhesive layer (B1) / substrate (B0) and a laminate of the adhesive layer (B2) / substrate (B0) were separately prepared (with the same coating conditions), and the 10° peel strengths P1 and P2 were measured by the above-mentioned method. The measurement results are shown in Table 1.

[0069] Example 3 To 269 parts by mass of silicone-modified (meth)acrylic resin solution NS, 1.0 part by mass of HDI isocyanurate (manufactured by Tosoh Corporation, product name: Coronate HX) and 2 parts by mass of Percadox 12XL25 manufactured by Kayaku Nouryon Co., Ltd. were added to obtain an adhesive coating liquid for temporary fixing material (B). This coating liquid was applied to a polyethylene terephthalate film (separator) treated with silicone release, and then dried at 100 ° C for 10 minutes to form an adhesive resin layer with a thickness of 100 μm. Next, a polyethylene terephthalate film (separator) treated with silicone release was attached to prepare a precursor of temporary fixing material (B) before heat treatment (with separators on both sides). The separators on both sides were peeled off, and the support plate (A) and wafer (C) described in Table 1 were laminated with a vacuum laminator, and heated at 140 ° C for 30 minutes to prepare a laminate (D) consisting of the support (A) / temporary fixing material (B) / wafer (C) in that order. The mechanical peelability and removability of the laminate (D) were evaluated, and the results are shown in Table 1. The 10° peel strengths P1 and P2 were measured according to the above-mentioned method (when the base film (B0) was not used as the temporary fixing material). The measurement results are shown in Table 1.

[0070] Example 4 The coating liquid for the adhesive layer (B1) on the support (A) side in Example 1 was applied to a silicone release-treated polyethylene terephthalate film (separator) and dried at 100° C. for 10 minutes to form an adhesive resin layer having a thickness of 31 μm. Next, a substrate B0 (PET film) was attached to the coating liquid to obtain a laminate of the adhesive layer (B1) on the support (A) side / substrate (B0) with a separator. Next, as the adhesive layer (B2) on the wafer (C) side, 100 parts by weight of (meth)acrylic resin emulsion A, 0.7 parts by weight of (meth)acrylic resin emulsion S, 0.3 parts by weight of dimethylethanolamine, 5 parts by weight of an epoxy compound (manufactured by Nagase Chemtex Corporation, product name: Ex-614), 9 parts by weight of butyl carbinol, and 12 parts by weight of pure water were mixed to prepare an adhesive coating liquid. This coating liquid was applied to a polyethylene terephthalate film (separator) that had been subjected to a silicone release treatment and dried at 120°C for 3 minutes to form an adhesive resin layer with a thickness of 20 μm. Next, the adhesive layer (B1) / substrate (B0) laminate was laminated to the substrate (B0) side to prepare a pre-heat-treated temporary fixing material (B) precursor having a three-layer structure of adhesive layer (B1) / substrate (B0) / adhesive layer (B2) with a separator. The separators used on both sides of the three-layer structure were peeled off, and the support (A) and wafer (C) shown in Table 1 were laminated using a vacuum laminator and heated at 140°C for 30 minutes to produce a laminate (D) consisting of the support (A) / temporary bonding material (B) / wafer (C) in that order. The mechanical peelability and removability of the laminate (D) were evaluated and the results are shown in Table 1. Separately, a laminate of the adhesive layer (B1) / substrate (B0) and a laminate of the adhesive layer (B2) / substrate (B0) were separately prepared (with the same coating conditions), and the 10° peel strengths P1 and P2 were measured by the above-mentioned method. The measurement results are shown in Table 1.

[0071] Comparative Example 1 To 69 parts by mass of silicone-modified (meth)acrylic resin solution N2, 0.1 parts by mass of HDI isocyanurate (manufactured by Tosoh Corporation, product name: Coronate HX), 6 parts by mass of pentaerythritol tri / tetraacrylate (manufactured by Toagosei Co., Ltd., product name: M-450), and 2 parts by mass of Percadox 12XL25 (manufactured by Kayaku Nouryon Co., Ltd.) were added to obtain an adhesive coating liquid for temporary fixing material (B). This coating liquid was applied to a silicone-release-treated polyethylene terephthalate film (separator), and then dried at 100°C for 10 minutes to form an adhesive resin layer with a thickness of 50 μm. Next, a silicone-release-treated polyethylene terephthalate film (separator) was attached to prepare a temporary fixing material (B) precursor before heat treatment (with double-sided separator). The separators on both sides were peeled off, and the support plate (A) and wafer (C) shown in Table 1 were laminated using a vacuum laminator and heated at 140°C for 30 minutes to produce a laminate (D) consisting of the support (A) / temporary bonding material (B) / wafer (C) in that order. The mechanical peelability and removability of the laminate (D) were evaluated and the results are shown in Table 1. The 10° peel strengths P1 and P2 were measured according to the above-mentioned method (when the base film (B0) was not used as the temporary fixing material). The measurement results are shown in Table 1.

[0072] [Table 1] [Industrial Applicability]

[0073] The wafer processing method of the present invention enables multiple and / or diverse processes to be performed on wafers with high productivity and yield without damaging electronic components such as functional layers formed on the wafer, and therefore contributes greatly to improving the productivity of electronic devices and has high applicability in various fields of industries such as the electronic components 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. [Explanation of symbols]

[0074] 11: Support (A) 12: Temporary fixing material (B) 13: Wafer (C) 14: Dicing tape 15: Ring frame 16: Remover 17: Adhesive tape 18: Adhesive layer (B2) on the wafer (C) side 19: Base film (B0) 20: Adhesive layer (B1) on support (A) side 21: Polyimide film

Claims

1. A step (1) of stacking a support (A), a temporary fixing material (B), and a wafer (C) located on the side of the temporary fixing material (B) opposite to the support (A); A step (2) of subjecting the wafer (C) to at least one treatment selected from a heat treatment, a mechanical processing treatment, a wet processing treatment, and a laser processing treatment; and A step (3) of separating the wafer (C) from the laminate (D) having the treated wafer (C); A method for processing a wafer, comprising: The 10° peel strength P between the support (A) and the temporary fixing material (B) was measured while keeping the angle between the peeled layers at 10°. １ and the 10° peel strength P between the temporary fixing material (B) and the wafer (C) ２ Ratio to P ２ / P １ is 1.1 or more, The method for treating a wafer as described above, wherein the temporary bonding material (B) contains a release agent.

2. Peel strength P １ The method for processing a wafer according to claim 1 , wherein the force is 10 N / 25 mm or less.

3. 3. The method for treating a wafer according to claim 1, wherein the adhesive layer in contact with the support body (A) and the adhesive layer in contact with the wafer (C) have different compositions.

4. 4. The method for treating a wafer according to claim 1, wherein separation of the wafer (C) from the laminate (D) is achieved by separating the support (A) from the temporary bonding material (B) and then removing the temporary bonding material (B) remaining on the wafer (C).

5. 5. The method for treating a wafer according to claim 4, wherein the method for separating the temporary bonding material (B) and the support (A) is mechanical peeling.

6. 6. The method for treating a wafer according to claim 1, wherein the temporary bonding material (B) contains a curable adhesive component.

7. The temporary fixing material (B) is a base film (B ０ 7. The method for treating a wafer according to claim 1, wherein the substrate is a substrate having a pressure-sensitive adhesive material laminated on both sides thereof.

8. The method for treating a wafer according to claim 1 , further comprising forming an electrode on the wafer (C).

9. 9. The method for treating a wafer according to claim 1, wherein in the step (2), a surface of the wafer (C) on which no electrode is formed is ground.

10. 10. The method for treating a wafer according to claim 9, wherein the thickness of the wafer (C) after grinding is 1 μm or more and 200 μm or less.

11. A method for manufacturing an electronic device, comprising carrying out the wafer processing method according to any one of claims 1 to 10.

12. The method for producing an electronic device according to claim 11 , wherein the electronic device has a structure in which semiconductor chips are stacked.

13. A laminate (D) in which a support (A), a temporary fixing material (B), and a wafer (C) located on a side of the temporary fixing material (B) opposite to the support (A), The 10° peel strength P between the support (A) and the temporary fixing material (B) was measured while keeping the angle between the peeled layers at 10°. １ and the 10° peel strength P between the temporary fixing material (B) and the wafer (C) ２ Ratio to P ２ / P １ is 1.1 or more, A laminate, wherein the temporary fixing material (B) contains a release agent.

Images