JP7351260B2 - Temporary adhesive for device substrates, device substrate laminate, and manufacturing method of device substrate laminate - Google Patents

Description

The present invention relates to a temporary adhesive for device substrates, a device substrate laminate, and a method for manufacturing a device substrate laminate, which makes it possible to effectively obtain a thin device substrate.

Three-dimensional semiconductor packaging is becoming essential to achieving even higher density and larger capacity. Three-dimensional packaging technology is a semiconductor manufacturing technology in which one semiconductor chip is made thinner and then stacked in multiple layers while being connected using through silicon vias (TSVs). In order to achieve this, it is necessary to reduce the thickness of the substrate on which the semiconductor circuit is formed by grinding the non-circuit-forming surface (hereinafter also referred to as the back surface), and further to form electrodes containing TSV on the back surface. Conventionally, in the backside grinding process of a silicon substrate, a backside protective tape is pasted on the opposite side of the grinding surface to prevent wafer damage during grinding. However, this tape uses an organic resin film as a base material, and although it is flexible, it has insufficient strength and heat resistance, and is not suitable for performing the TSV forming process or the wiring layer forming process on the back side.

Therefore, a system has been proposed in which a device substrate such as a semiconductor substrate is bonded to a support such as silicon or glass via an adhesive layer so that it can sufficiently withstand the processes of back grinding, TSV, and back electrode formation. What is important here is the adhesive layer used to bond the substrate to the support. This requires that the substrate can be bonded to the support without any gaps, that it has sufficient durability to withstand subsequent steps, and that finally the thin wafer can be easily peeled off from the support. In this specification, this adhesive layer is referred to as a temporary adhesive layer because it is peeled off last.

As for the temporary adhesive layer and its peeling method known so far, the temporary adhesive layer is peeled from the support by irradiating the adhesive containing a light-absorbing substance with high-intensity light to decompose the temporary adhesive layer. (Patent Document 1) and a technique (Patent Document 2) in which a heat-melting hydrocarbon compound is used as an adhesive and bonding and peeling are performed in a heated molten state have been proposed. The former technique requires expensive equipment such as a laser and has problems such as a long processing time per substrate. Furthermore, although the latter technique is simple because it is controlled by heating alone, its range of application is narrow because it has insufficient thermal stability at high temperatures exceeding 200°C. Furthermore, these adhesives were not suitable for forming a uniform film thickness on a high-level substrate and for completely adhering to a support.

A technique using a silicone adhesive as a temporary adhesive layer has been proposed (Patent Document 3). In this method, the substrate is bonded to the support using an addition-curing silicone adhesive, and when peeling, the substrate is separated from the support by immersing it in a chemical that dissolves or decomposes the silicone resin. . Therefore, peeling takes a very long time, making it difficult to apply to actual manufacturing processes. In addition, a temporary adhesive has been proposed that has excellent heat resistance during wafer processing, good temporary adhesion, and good releasability at room temperature (Patent Document 4). However, since this temporary adhesive has a three-layer structure, it is complicated and requires application to the substrate three times.

JP2004-64040A Japanese Patent Application Publication No. 2006-328104 US Patent No. 7541264 Japanese Patent Application Publication No. 2014-131004

The present invention has been developed in view of the above circumstances, and allows for easy temporary adhesion, enables formation of a high-level substrate with a uniform film thickness, and has high process compatibility with TSV formation and backside wiring processes. Furthermore, a temporary adhesive for device substrates, a device substrate laminate, and a method for manufacturing a device substrate laminate, which have excellent resistance to heat processes such as CVD, are easy to peel and clean, and can improve productivity of thin device substrates. The purpose is to provide

As a result of intensive studies to achieve the above object, the present inventors have found that a non-silicone thermoplastic resin and a silicone resin with a glass transition temperature of 200°C or higher are used for temporary bonding between a device substrate and a support. , and a structure in which a device substrate, a non-silicone thermoplastic resin-containing layer, a silicone resin-containing layer, and a support are formed in this order, it is possible to easily manufacture a thin device substrate having a through electrode structure or a bump connection structure. They discovered this and completed the present invention.

Therefore, the present invention provides the following temporary adhesive for device substrates, a device substrate laminate, and a method for manufacturing a device substrate laminate.
1. A temporary adhesive for a device substrate, including (A) a resin layer A containing a non-silicone thermoplastic resin having a glass transition temperature of 200° C. or higher, and (B) a resin layer B containing a silicone resin.
2. 1. A temporary adhesive for device substrates, wherein the non-silicone thermoplastic resin is at least one selected from polyimide, polyetherimide, polyether sulfone, aromatic polyether, aromatic polyester, and modified resins thereof.
3. Temporary adhesive for a device substrate according to 1 or 2, wherein the silicone resin has a viscosity of 7,000 Pa·s or more at 25°C, and the silicone resin has a minimum viscosity of 50 to 5,000 Pa·s in the range of 80 to 150°C. agent.
4. The temporary adhesive for device substrates according to 3, wherein the silicone resin has a viscosity of 10,000 Pa·s or more at 25°C, and the silicone resin has a minimum viscosity of 50 to 1,000 Pa·s in the range of 80 to 150°C.
5. A laminate comprising a device substrate, a temporary adhesive layer, and a support in this order, wherein the temporary adhesive layer is made of (A) a non-silicone-based heat treatment having a glass transition temperature of 200° C. or higher, in order from the device substrate side; A device substrate laminate including a resin layer A containing a plastic resin and (B) a resin layer B containing a silicone resin.
6.5 A method for manufacturing a device substrate laminate, comprising:
(a) Forming a resin layer A containing a non-silicone thermoplastic resin having a glass transition temperature of 200° C. or higher on a device substrate, and forming a resin layer B containing a silicone resin on a support, and ( b) A method for manufacturing a device substrate laminate, including the step of bonding together a device substrate on which a resin layer A is formed and a support body on which a resin layer B is formed, with the resin layer A and the resin layer B interposed therebetween.

By using the temporary adhesive for device substrates of the present invention, it is easy to temporarily bond the device substrate and the support, it has excellent workability in high-temperature areas, and it is also possible to form a high-step substrate with a uniform film thickness. It has high process suitability for TSV formation and backside wiring processes, and also has good resistance to thermal processes such as CVD, and is easy to peel off after processing, making it possible to improve the productivity of thin device substrates.

The temporary adhesive for device substrates of the present invention includes (A) resin layer A containing a non-silicone thermoplastic resin having a glass transition temperature of 200° C. or higher, and (B) resin layer B containing silicone resin.

[(A) Resin layer A]
(A) Resin layer A contains a non-silicone thermoplastic resin having a glass transition temperature (Tg) of 200° C. or higher. Examples of such resins include modified resins thereof such as polyimide, polyetherimide, polyether sulfone, aromatic polyether, aromatic polyester, and acrylic resin. Among these, aromatic polyethers and aromatic polyesters are particularly preferred.

The weight average molecular weight (Mw) of the thermoplastic resin is preferably 5,000 to 50,000, more preferably 10,000 to 30,000. If Mw is within the above range, both heat resistance and solvent solubility can be ensured. In the present invention, Mw is a value measured in terms of polystyrene by gel permeation chromatography (GPC) using tetrahydrofuran (THF) as a solvent.

The thermoplastic resin may be synthesized by a known method, or a commercially available product may be used. Commercially available products include, for example, Unifiner (registered trademark) M-2000H, M-2040, V-575, W-575 (manufactured by Unitika Co., Ltd.), Zylon (registered trademark) 200H, 240V, 300H, 340V, 400H. , 500H (manufactured by Asahi Glass Co., Ltd.).

The resin layer A can be formed using a composition containing the non-silicone thermoplastic resin (hereinafter also referred to as thermoplastic resin composition A). A specific forming method will be described later.

Thermoplastic resin composition A may be a solution containing a solvent. Examples of the solvent include hydrocarbon solvents such as isooctane, nonane, p-menthane, pinene, p-xylene, and cyclohexanone. Among these, nonane, p-menthane, isooctane, p-xylene, and cyclohexanone are preferred from the viewpoint of coating properties.

Thermoplastic resin composition A may contain a known antioxidant in order to improve its heat resistance. The antioxidant is preferably di-tert-butylphenol or the like. When the antioxidant is included, its content is preferably 0.01 to 5 parts by weight, more preferably 0.1 to 2 parts by weight, based on 100 parts by weight of the non-silicone thermoplastic resin.

Furthermore, the thermoplastic resin composition A may contain a surfactant in order to improve coating uniformity. The surfactant is preferably a fluorosilicone surfactant, such as X-70-1102 (manufactured by Shin-Etsu Chemical Co., Ltd.). When the surfactant is included, its content is preferably 0.001 to 3 parts by weight, more preferably 0.01 to 1 part by weight, based on 100 parts by weight of the non-silicone thermoplastic resin.

Moreover, the thermoplastic resin composition A can also be used as a film-like composition that does not contain a solvent.

The thickness of the resin layer A is not particularly limited and may be set appropriately depending on the level difference on the device substrate, but it is usually preferably 0.5 to 50 μm, more preferably 5 to 20 μm. If the thickness of the resin layer A is within the above range, it is possible to fill in the steps of the device substrate and ensure good bonding properties.

[(B) Resin layer B]
(B) Resin layer B contains silicone resin. The silicone resin is not particularly limited, but is preferably a thermosetting silicone resin.

The silicone resin contained in resin layer B preferably has a viscosity of 7,000 Pa·s or more at 25°C, and a minimum viscosity of 50 to 5,000 Pa·s in the range of 80 to 150°C. It is more preferable that the viscosity is 10,000 Pa·s or more, and the minimum viscosity in the range of 80 to 150°C is 50 to 1,000 Pa·s. The upper limit of the viscosity of the silicone resin at 25° C. is preferably 100,000,000 Pa·s or less, more preferably 5,000,000 Pa·s or less. In the present invention, the viscosity is a value measured using a rheometer.

The silicone resin may be a thermosetting modified silicone resin (hereinafter also referred to as silicone resin B1) containing a unit represented by the following formula (1) and a unit represented by the following formula (2), or a thermosetting modified silicone resin containing the following formula ( A thermosetting modified silicone resin (hereinafter also referred to as silicone resin B2) containing a unit represented by 3) and a unit represented by the following formula (4) is preferred. In addition, from the viewpoint of heat resistance, silicone resin B1 is preferable.

In formulas (1) to (4), R ¹ to R ⁸ are each independently a monovalent hydrocarbon group having 1 to 8 carbon atoms. p and q are each independently an integer of 1 to 100. A and B are numbers satisfying 0<A≦1, 0≦B≦1, and 0.5≦A+B≦1. C and D are numbers satisfying 0<C≦1, 0≦D≦1, and 0.5≦C+D≦1. Further, B/A is preferably 0 to 20, more preferably 0.5 to 5. D/C is preferably 0 to 20, more preferably 0.5 to 5.

In formulas (1) and (3), p and q are each independently an integer of 1 to 100, preferably an integer of 3 to 60, more preferably an integer of 8 to 40.

In formulas (1) to (4), X ¹ is a divalent group represented by the following formula (5), and X ² is a divalent group represented by the following formula (6).

In formulas (5) and (6), Y ¹ and Y ² each independently represent a single bond, methylene group, propane-2,2-diyl group, 1,1,1,3,3,3-hexafluoro It is a propane-2,2-diyl group or a fluorene-9,9-diyl group. R ¹¹ to R ¹⁴ are each independently an alkyl group or an alkoxy group having 1 to 4 carbon atoms. Specific examples of R ¹¹ to R ¹⁴ include methyl group, ethyl group, phenyl group, methoxy group, and ethoxy group. r, s, t and u are each independently 0, 1 or 2.

In formulas (1) and (2), when there are two or more siloxane units (that is, when p and q are each an integer of 2 or more), the siloxane units may be all the same or two or more different types. It may also contain siloxane units. When two or more different types of siloxane units are included, the siloxane units may be randomly bonded or alternately bonded, or may include a plurality of blocks of the same type of siloxane units.

The Mw of silicone resin B1 is preferably 3,000 to 500,000, more preferably 10,000 to 100,000. Further, the Mw of silicone resin B2 is preferably 3,000 to 500,000, more preferably 10,000 to 100,000. Further, the silicone (siloxane unit) content in the silicone resins B1 and B2 is preferably 10 to 80% by mass in the resin. Note that the silicone content is the mass percentage of the siloxane unit-containing raw material with respect to the total mass of each monomer that becomes the raw material of the silicone resin.

When using silicone resin B1 or B2 as the silicone resin, resin layer B can be formed using a resin composition (hereinafter also referred to as silicone resin composition B) containing silicone resin B1 or B2. A specific forming method will be described later.

The silicone resin composition B preferably contains a crosslinking agent in order to be thermally cured. When using silicone resin B1, at least one of an epoxy compound having an average of two or more epoxy groups in one molecule or a phenol compound having an average of two or more phenolic hydroxy groups in one molecule is used. It is preferably included as a crosslinking agent. When using silicone resin B2, nitrogen-containing compounds such as melamine compounds, guanamine compounds, glycoluril compounds, urea compounds, etc., which contain an average of two or more methylol groups and/or alkoxymethyl groups in one molecule, and these At least one selected from condensates, phenol compounds having an average of two or more methylol groups or alkoxymethyl groups in one molecule, and epoxy compounds having an average of two or more epoxy groups in one molecule. It is preferably included as a crosslinking agent.

Epoxy compounds having an average of two or more epoxy groups in one molecule are not particularly limited, but include bifunctional, trifunctional, tetrafunctional or higher functional epoxy resins, such as those manufactured by Nippon Kayaku Co., Ltd. Examples include EOCN-1020 (see formula below), EOCN-102S, XD-1000, NC-2000-L, EPPN-201, GAN, NC6000, and those represented by the formula below.

Examples of phenolic compounds having an average of two or more phenolic hydroxyl groups in one molecule include m- or p-cresol novolac resins (for example, EP-6030G manufactured by Asahi Yokuzai Kogyo Co., Ltd.), trifunctional phenols, Compounds (for example, TrisP-PA manufactured by Honshu Kagaku Kogyo Co., Ltd.), tetrafunctional phenol compounds (for example, TEP-TPA manufactured by Asahi Yokuzai Kogyo Co., Ltd.), and the like.

The content of the crosslinking agent is preferably 0.1 to 50 parts by weight, more preferably 0.1 to 30 parts by weight, and even more preferably 1 to 20 parts by weight, based on 100 parts by weight of the silicone resin B1 or B2. The crosslinking agents may be used alone or in combination of two or more.

Moreover, the silicone resin composition B may also contain a curing catalyst such as an acid anhydride. When a curing catalyst is included, its content is preferably 0.1 to 10 parts by mass based on 100 parts by mass of silicone resin B1 or B2.

Silicone resin composition B may be a solution containing a solvent. Examples of the solvent include ketones such as cyclohexanone, cyclopentanone, and methyl-2-n-amyl ketone; 3-methoxybutanol, 3-methyl-3-methoxybutanol, 1-methoxy-2-propanol, and 1-ethoxy-2 -Alcohols such as propanol; Ethers such as propylene glycol monomethyl ether, ethylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monoethyl ether, propylene glycol dimethyl ether, diethylene glycol dimethyl ether; propylene glycol monomethyl ether acetate, propylene glycol monoethyl Ether acetate, ethyl lactate, ethyl pyruvate, butyl acetate, methyl 3-methoxypropionate, ethyl 3-ethoxypropionate, tert-butyl acetate, tert-butyl propionate, propylene glycol mono-tert-butyl ether acetate, γ-butyrolactone Examples include esters such as.

The content of the solvent is preferably 10 to 90 parts by weight, more preferably 30 to 70 parts by weight, based on 100 parts by weight of silicone resin B1 or B2. The above-mentioned solvents can be used alone or in combination of two or more.

Silicone resin composition B may also contain a known antioxidant in order to further improve heat resistance. As the antioxidant, conventionally known ones can be used, but it is preferably at least one selected from hindered phenol compounds, hindered amine compounds, organic phosphorus compounds, and organic sulfur compounds. When an antioxidant is included, its content is preferably 0.01 to 5 parts by weight, more preferably 0.1 to 3 parts by weight, based on 100 parts by weight of silicone resin B1 or B2. The antioxidants may be used alone or in combination of two or more.

Silicone resin composition B may also contain a filler such as silica to further improve heat resistance. When a filler is included, its content is preferably 1 to 50 parts by mass based on 100 parts by mass of silicone resin B1 or B2.

Silicone resin composition B may further contain a surfactant to improve coating uniformity. When a surfactant is included, the content thereof is preferably 0.01 to 3 parts by mass based on 100 parts by mass of silicone resin B1 or B2.

Moreover, the silicone resin composition B can also be used as a film-like composition that does not contain a solvent.

By using such a thermosetting modified silicone resin, not only does the resin not undergo thermal decomposition, but it also does not flow at high temperatures and has high heat resistance, making it suitable for a wide range of semiconductor film forming processes. It can be applied to device substrates with steps, making it possible to form a temporary adhesive layer with highly uniform thickness, and furthermore, after fabricating a thin device substrate, the device substrate can be easily peeled off from the support at room temperature. Therefore, thin wafers that are easily broken can be easily manufactured.

In addition, as the silicone resin contained in resin layer B, (B3-1) organopolysiloxane having two or more alkenyl groups in one molecule, (B3-2) (B3-1) (B3-2) organohydrogenpolysiloxane having two or more SiH groups in one molecule in an amount such that the molar ratio of SiH groups in the component is 0.3 to 10, (B3-3) (B3- A composition containing 0.1 to 10 parts by mass of a reaction control agent and a platinum-based catalyst (B3-4) based on a total of 100 parts by mass of components 1) and (B3-2) (hereinafter referred to as silicone resin composition) It is also possible to use a silicone resin (hereinafter also referred to as silicone resin B3) obtained by curing B'.

Component (B3-1) is a linear or branched diorganopolysiloxane having two or more alkenyl groups in one molecule, and in particular, the alkenyl group content in one molecule is 0.6 to 9 mol. % is preferred. In the present invention, the alkenyl group content is the ratio (mol%) of the number of alkenyl groups to the number of Si atoms in the molecule.

Examples of such diorganopolysiloxanes include those represented by the following formula (7) and those represented by the following formula (8).

In formulas (7) and (8), R ²¹ to R ³² are each independently a monovalent hydrocarbon group having no aliphatic unsaturated bond. Z ¹ to Z ⁴ are each independently a monovalent organic group having an alkenyl group. a and b are each independently an integer of 0 to 3, and m ¹ , m ² , n ¹ and n ² are 0≦m ¹ ≦200, 2≦m ² ≦200, 0≦n ¹ ≦200. and 0≦n ² ≦200. a, b, m ¹ , m ² , n ¹ and n ² are preferably numbers such that the alkenyl group content is 0.6 to 9 mol%.

The monovalent hydrocarbon group having no aliphatic unsaturated bond is preferably one having 1 to 10 carbon atoms, such as an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group; a cyclo group such as a cyclohexyl group; Alkyl group: Examples include aryl groups such as phenyl group and tolyl group, and particularly preferred are alkyl groups such as methyl group or phenyl group.

The monovalent organic group having an alkenyl group is preferably one having 2 to 10 carbon atoms, such as alkenyl groups such as vinyl group, allyl group, hexenyl group, octenyl group; acryloylpropyl group, acryloylmethyl group, methacryloylpropyl group. (meth)acryloyl alkyl groups such as groups; (meth)acryloxyalkyl groups such as acryloxypropyl group, acryloxymethyl group, methacryloxypropyl group, methacryloxymethyl group; cyclohexenylethyl group, vinyloxypropyl group, etc. Examples include alkenyl group-containing monovalent hydrocarbon groups, with vinyl groups being particularly preferred from an industrial standpoint.

In formula (7), a and b are each independently an integer of 0 to 3, but if a and b are integers of 1 to 3, the molecular chain terminal is blocked with an alkenyl group, so that the reaction will not occur. This alkenyl group at the end of the molecular chain allows the reaction to be completed in a short time, which is preferable. Furthermore, in terms of cost, it is industrially preferable that a=1 and b=1.

The alkenyl group-containing diorganopolysiloxane component (B3-1) preferably has an oil-like or raw rubber-like property. The alkenyl group-containing diorganopolysiloxane may be linear or branched.

Component (B3-2) is a crosslinking agent, and is an organohydrogenpolysiloxane having at least two, preferably three or more hydrogen atoms (SiH groups) bonded to silicon atoms in one molecule. The organohydrogenpolysiloxane may be linear, branched, or cyclic.

The viscosity at 25° C. of the organohydrogenpolysiloxane (B3-2) is preferably 1 to 5,000 mPa·s, more preferably 5 to 500 mPa·s. This organohydrogenpolysiloxane may be a mixture of two or more types.

The amount of component (B3-2) to be used is such that the total of SiH groups in component (B3-2) to the total of alkenyl groups in component (B3-1) is a molar ratio (SiH group/alkenyl group) of 0. The amount is preferably from .3 to 10, and more preferably from 1.0 to 8. If the molar ratio is 0.3 or more, the crosslinking density will not become low and the problem that the adhesive layer will not be cured will not occur. When the molar ratio is 10 or less, sufficient adhesive strength and tack can be obtained without the crosslinking density becoming too high. Further, if the molar ratio is 10 or less, the usable time of the treatment liquid can be extended.

(B3-3) Component is a reaction control agent, which is used to prevent the processing liquid from thickening or gelling before heating and curing when preparing or coating silicone resin composition B' on a substrate. It is optionally added as necessary. Specific examples include 3-methyl-1-butyn-3-ol, 3-methyl-1-pentyn-3-ol, 3,5-dimethyl-1-hexyn-3-ol, 1-ethynylcyclohexanol, 3-Methyl-3-trimethylsiloxy-1-butyne, 3-methyl-3-trimethylsiloxy-1-pentyne, 3,5-dimethyl-3-trimethylsiloxy-1-hexyne, 1-ethynyl-1-trimethylsiloxycyclohexane , bis(2,2-dimethyl-3-butynoxy)dimethylsilane, 1,3,5,7-tetramethyl-1,3,5,7-tetravinylcyclotetrasiloxane, 1,1,3,3-tetra Examples include methyl-1,3-divinyldisiloxane. Among these, 1-ethynylcyclohexanol and 3-methyl-1-butyn-3-ol are preferred.

When silicone resin composition B' contains component (B3-3), its content is usually 0.01 to 8 parts by mass based on the total of 100 parts by mass of components (B3-1) and (B3-2). The amount is preferably 0.05 to 2 parts by weight. If the amount is 8 parts by mass or less, the curability of silicone resin composition B' will not decrease, and if it is 0.01 part by mass or more, the reaction control effect will be sufficiently exhibited.

The component (B3-4) is a platinum-based catalyst (that is, a platinum group metal catalyst), such as chloroplatinic acid, an alcoholic solution of chloroplatinic acid, a reaction product of chloroplatinic acid and alcohol, or a chloroplatinic acid and olefin compound. and a reaction product of chloroplatinic acid and a vinyl group-containing siloxane.

The content of component (B3-4) is an effective amount, which is usually 1 to 5,000 ppm as a platinum content (in terms of mass), based on the total of components (B3-1) to (B3-3), and 5 to Preferably it is 2,000 ppm. If it is 1 ppm or more, the curability of the silicone resin composition B' will not decrease, the crosslinking density will not decrease, and the holding power will not decrease. If it is 5,000 ppm or less, the usable time of the treatment bath can be extended.

The resin layer B further contains R ^A ₃ SiO _0.5 units (wherein R ^A is each independently an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms) and a SiO ₂ unit, An organopolysiloxane having a molar ratio of R ^A ₃ SiO _0.5 units/SiO ₂ units of 0.3 to 1.8 may be added. When added, the amount added is preferably 0 to 30 parts by mass per 100 parts by mass of component (B3-1) in resin layer B.

The thickness of the resin layer B is preferably 0.1 to 60 μm, more preferably 5 to 40 μm. If the thickness of the resin layer B is 0.1 μm or more, it can be coated on the entire surface without leaving any uncoated parts, and if it is 60 μm or less, it can withstand the grinding process when forming thin wafers. can.

[Device substrate laminate]
The device substrate laminate of the present invention is a laminate including a device substrate, a temporary adhesive layer, and a support in this order, wherein the temporary adhesive layer includes the resin layer A and the resin layer in this order from the device substrate side. It includes B.

Although the device substrate is not particularly limited, it is usually a semiconductor wafer. Examples of such semiconductor wafers include silicon wafers, germanium wafers, gallium-arsenide wafers, gallium-phosphorus wafers, gallium-arsenide-aluminum wafers, and the like. The thickness of the wafer is not particularly limited, but is usually preferably 600 to 800 μm, more preferably 625 to 775 μm.

As the support, a silicon wafer, a glass plate, a quartz wafer, etc. can be used, but the support is not limited thereto. In addition, in the present invention, it is not necessary to irradiate the temporary adhesive layer with radiant energy rays through the support, and the light transmittance of the support is not required. The thickness of the support is preferably 600 to 800 μm, more preferably 625 to 775 μm.

[Method for manufacturing device substrate laminate]
The method for manufacturing a device substrate laminate of the present invention includes the following steps (a) and (b).
[Step (a)]
Step (a) is a step of forming a resin layer A on one side of the device substrate and forming a resin layer B on one side of the support. When the device substrate has a circuit-forming surface on one side and a circuit-free surface on the other side, the resin layer A is formed on the circuit-forming surface.

When thermoplastic resin composition A is a solution, resin layer A can be formed by applying this to a device substrate and baking it. At this time, examples of the coating method include spin coating, spray coating, and slit coating. The baking conditions are not particularly limited as long as the solvent can be evaporated, but baking can usually be carried out at 80 to 200°C for 1 to 10 minutes.

Moreover, when the thermoplastic resin composition A is a film-like composition, the resin layer A can be formed on the device substrate by a lamination method.

Similarly, for the resin layer B, if the silicone resin composition B or B' is a solution, it is applied to the support and baked, or if it is a film composition, it is applied to the support by a laminating method. A resin layer B can be formed. Note that the coating method and baking conditions are the same as those described above.

[Step (b)]
Step (b) is a step of bonding together the device substrate on which the resin layer A is formed and the support body on which the resin layer B is formed, with the resin layer A and the resin layer B interposed therebetween. At this time, resin layer A and resin layer B are bonded together under a reduced pressure of preferably 100 Pa or less, more preferably 10 Pa or less at a temperature range of preferably 40 to 200°C, more preferably 60 to 180°C. Press uniformly to form a laminate. The pressure during crimping is preferably 0.01 to 10 MPa, more preferably 0.1 to 5 MPa. The bonding can be performed using a commercially available wafer bonding apparatus, such as EVG520IS and 850TB from EVG, and XBC300 from SUSS.

[Step (c)]
After step (b), the resin layer B may be thermally cured (step (c)). Thermal curing can be carried out by heating the laminate formed in step (b), preferably at 120 to 220°C for 10 minutes to 4 hours, more preferably at 150 to 200°C for 30 minutes to 2 hours. .

[Method for manufacturing thin device substrate]
A thin device substrate can be manufactured by grinding or polishing the device substrate of the laminate, processing the non-circuit-forming surface, and peeling the device substrate from the laminate. A specific example of a method for manufacturing a thin device substrate includes a method including the following steps (d) to (f).

[Step (d)]
Step (d) is a step of grinding or polishing the non-circuit-forming surface of the device substrate laminate, that is, a step of polishing or grinding the back surface of the device substrate of the laminate to reduce the thickness of the device substrate. be. The method of polishing or grinding the back surface of the device substrate is not particularly limited, and a known method may be employed. Polishing or grinding is preferably performed while cooling the device substrate and a grindstone (diamond or the like) by pouring water over them. An example of an apparatus for polishing or grinding the back surface of a device substrate is DAG-810 (trade name) manufactured by Disco Corporation. Alternatively, the back surface of the device substrate may be polished by CMP.

[Step (e)]
Step (e) is a step of processing the circuit-free surface of the device substrate of the laminate obtained by grinding the non-circuit-forming surface of the device substrate, that is, the layered product whose thickness has been reduced by back grinding. This step includes various processes used at the wafer level. Examples include electrode formation, metal wiring formation, protective film formation, and the like. More specifically, metal sputtering for forming electrodes, etc., wet etching for etching a metal sputtered layer, resist coating, exposure, and development to form a pattern as a mask for metal wiring formation, and resist peeling. Conventionally known processes include dry etching, metal plating formation, silicon etching for TSV formation, and oxide film formation on the silicon surface.

[Step (f)]
Step (f) is a step of peeling the device substrate processed in step (e) from the laminate. This peeling step is usually carried out at a relatively low temperature of about room temperature to 60°C. Examples of the peeling method include a method in which one of the device substrate or the support of the laminate is fixed horizontally, and the other is lifted at a certain angle from the horizontal direction.

Further, after step (f), it is preferable to perform a step (g) of removing the temporary adhesive layer (particularly resin layer A) remaining on the circuit forming surface of the peeled device substrate. Part of the resin layer A may remain on the circuit forming surface of the device substrate peeled from the support in step (f), and the resin layer A can be removed by, for example, cleaning the device substrate. This can be done by

In cleaning the device substrate, any cleaning liquid that can dissolve the thermoplastic resin in the resin layer A can be used. Examples of such a cleaning liquid include organic solvents such as pentane, hexane, cyclohexane, decane, isononane, p-menthane, pinene, isododecane, limonene, cyclopentanone, cyclohexanone, and propylene glycol monomethyl ether. These organic solvents may be used alone or in combination of two or more.

Examples of methods for cleaning the device substrate include a method of cleaning with a paddle using the cleaning liquid, a method of cleaning by spraying, and a method of immersing in a cleaning liquid tank. The temperature during washing is preferably 10 to 80°C, more preferably 15 to 65°C.

After the resin layer A is dissolved with the cleaning liquid, rinsing with water or alcohol may be performed as necessary, and drying may be performed.

The thickness of the thin device substrate obtained by the manufacturing method of the present invention is typically 5 to 300 μm, more typically 10 to 100 μm.

Hereinafter, the present invention will be explained in more detail by showing synthesis examples, preparation examples, examples, and comparative examples, but the present invention is not limited to the following examples. The Mw is calculated using TSKgel Super HZM-H (manufactured by Tosoh Corporation) as a column, under the analysis conditions of a flow rate of 0.6 mL/min, an elution solvent of THF, and a column temperature of 40°C, using GPC with monodisperse polystyrene as the standard. It was measured by

Compounds (M-1) to (M-6) used in the following synthesis examples are as follows.

[1] Preparation of silicone resin solution [Synthesis Example 1]
In a 5 L flask equipped with a stirrer, thermometer, nitrogen purge device and reflux condenser, 43.1 g of compound (M-1), 29.5 g of compound (M-3), 135 g of toluene and 0.04 g of chloroplatinic acid were added. The mixture was prepared and heated to 80°C. Thereafter, 17.5 g of compound (M-5) was added dropwise into the flask over 1 hour. At this time, the temperature inside the flask rose to 85°C. After completion of the dropwise addition, the mixture was further aged at 80° C. for 2 hours, toluene was distilled off, and 80 g of cyclohexanone was added to obtain a resin solution using cyclohexanone as a solvent and having a resin concentration of 50% by mass. The Mw of the resin in this solution was 45,000. Further, to 50 g of this resin solution, 7.5 g of EOCN-1020 (manufactured by Nippon Kayaku Co., Ltd.), an epoxy crosslinking agent, and BSDM (Bis(tert-), manufactured by Fuji Film Wako Pure Chemical Industries, Ltd.) as a curing catalyst were added. butylsulfonyl)diazomethane) and 0.1 g of ADEKA STAB (registered trademark) AO-60 (hindered phenol antioxidant manufactured by ADEKA Co., Ltd.) as an antioxidant, and filtered with a 1 μm membrane filter. As a result, a silicone resin solution B1 was obtained.

[Synthesis example 2]
84.1 g of compound (M-2) and 600 g of toluene were put into a 5 L flask equipped with a stirrer, a thermometer, a nitrogen purge device, and a reflux condenser, and after dissolving, 294.6 g of compound (M-3) and the compound 25.5 g of (M-4) was added and heated to 60°C. Thereafter, 1 g of carbon-supported platinum catalyst (5% by mass) was added, and after confirming that the internal reaction temperature rose to 65 to 67°C, the mixture was further heated to 90°C and aged for 3 hours. After cooling to room temperature, 600 g of methyl isobutyl ketone (MIBK) was added, and the resulting solution was filtered under pressure using a filter to remove the platinum catalyst. The solvent in this resin solution was distilled off under reduced pressure, and 200 g of propylene glycol monomethyl ether acetate (PGMEA) was added to obtain a resin solution using PGMEA as a solvent and having a resin concentration of 60% by mass. The Mw of the resin in this solution was 28,000. Furthermore, to 100 g of this resin solution, 9 g of TEP-TPA (manufactured by Asahi Yakuzai Kogyo Co., Ltd.), which is a tetrafunctional phenol compound, was added as a crosslinking agent, and tetrahydrophthalic anhydride (manufactured by Shin Nippon Chemical Co., Ltd., Rikacid) was added as a curing catalyst. HH-A) 0.2 g was added and filtered through a 1 μm membrane filter to obtain silicone resin solution B2.

[Synthesis example 3]
84.1 g of compound (M-2) and 600 g of toluene were put into a 5 L flask equipped with a stirrer, a thermometer, a nitrogen purge device, and a reflux condenser, and after dissolving, 14.6 g of compound (M-3) and the compound 125.5 g of (M-5) was added and heated to 60°C. Thereafter, 1 g of carbon-supported platinum catalyst (5% by mass) was added, and after confirming that the internal reaction temperature rose to 65 to 67°C, the mixture was further heated to 90°C and aged for 3 hours. After cooling to room temperature, 600 g of MIBK was added, and the resulting solution was filtered under pressure using a filter to remove the platinum catalyst. The solvent in this resin solution was distilled off under reduced pressure, and 70 g of PGMEA was added to obtain a resin solution using PGMEA as a solvent and having a resin concentration of 60% by mass. The Mw of the resin in this solution was 32,000. Furthermore, to 100 g of this resin solution, 15 g of TrisP-PA (manufactured by Honshu Kagaku Kogyo Co., Ltd.) was added as a crosslinking agent, 0.2 g of n-hexylimidazole as a curing catalyst, and 0.1 g of Adekastab AO-60 as an antioxidant. was added and filtered through a 1 μm membrane filter to obtain silicone resin solution B3.

[Synthesis example 4]
The compound (M-6 ) and 0.7 parts by mass of ethynylcyclohexanol were added and mixed. The molar ratio (SiH/SiVi) of the SiH groups in the organohydrogenpolysiloxane to the vinyl groups in the vinyl group-containing polydimethylsiloxane was 1.1. Further, 0.5 parts by mass of platinum catalyst CAT-PL-5 (manufactured by Shin-Etsu Chemical Co., Ltd.) was added and filtered through a 0.2 μm membrane filter to obtain silicone resin solution B4.

[2] Preparation of non-silicone thermoplastic resin solution [Preparation Example 1]
20 g of Unifiner M-2000H (Mw = 35,000, manufactured by Unitika Co., Ltd.), which is a polyarylate resin, was dissolved in 134 g of cyclohexanone, and the resulting solution was filtered with a 0.2 μm membrane filter to give a concentration of 13% by mass. A non-silicone thermoplastic resin solution A1 was obtained. The Tg of the resin was measured in accordance with JIS K 7121 and was found to be 270°C.

[Preparation example 2]
20 g of Zylon S201A (Mw = 15,000, manufactured by Asahi Kasei Corporation), which is a polyphenylene ether resin, was dissolved in 180 g of p-xylene, and the resulting solution was filtered through a 1 μm membrane filter to obtain 10% by mass of non-silicone. A thermoplastic resin solution A2 was obtained. The Tg of the resin was measured in accordance with JIS K 7121 and was found to be 218°C.

[Preparation example 3]
24 g of Septon 2002 (Mw = 43,000, manufactured by Kuraray Co., Ltd.), which is a hydrogenated polystyrene thermoplastic resin, was dissolved in 176 g of isononane, and the resulting solution was filtered with a 0.2 μm membrane filter to obtain 12 mass % non-silicone thermoplastic resin solution A3 was obtained. The Tg of the resin was measured in accordance with JIS K 7121 and was found to be 89°C.

[3] Production of laminate and evaluation thereof [Examples 1 to 5 and Comparative Example 1]
A silicon wafer with a diameter of 200 mm and a thickness of 725 μm on which copper posts with a height of 10 μm and a diameter of 40 μm are formed on the entire surface is spin-coated with a non-silicone thermoplastic resin solution A1, A2, or A3, and then coated on a hot plate for 150 μm. ℃ for 5 minutes, a resin layer A having a thickness shown in Table 1 was formed on the copper post forming surface.
On the other hand, silicone resin solutions B1, B2, B3, or B4 were spin-coated onto a glass plate with a diameter of 200 mm and a thickness of 700 μm as a support, and then heated on a hot plate at 150°C for 3 minutes. A resin layer B having a thickness shown in Table 1 was formed.

In this way, the silicon wafer on which the resin layer A was formed and the glass plate on which the resin layer B was formed were placed in a vacuum bonding apparatus (manufactured by EVG, EVG520IS) so that the resin layers A and B were combined. ) under reduced pressure conditions of 0.1 Pa or less at 120° C. and a load of 5 kN to produce a device substrate laminate.

The following tests were conducted on the device substrate laminate. The results are shown in Table 1. Note that the evaluation was performed in the following order.

(1) Adhesion test Visually check the adhesion status of the interface, and if no abnormality such as air bubbles occurs at the interface, it is evaluated as good and marked with "○", and if any abnormality occurs, it is evaluated as poor. and indicated with an “x”.

(2) Back Grinding Resistance Test The back surface of the silicon wafer was ground with a grinder (DAG810, manufactured by DISCO Co., Ltd.) using a diamond grindstone. After grinding to a final substrate thickness of 50 μm, the presence or absence of abnormalities such as cracks and peeling was examined using an optical microscope (100x magnification). A case where no abnormality occurred was evaluated as good and indicated by "○", and a case where an abnormality occurred was evaluated as poor and indicated by "x".

(3) CVD resistance test The workpiece after back-grinding the silicon wafer was introduced into a CVD apparatus, and an experiment was conducted to form a 2 μm SiO ₂ film, and the presence or absence of any abnormality in appearance was examined. A case in which no appearance abnormality occurred was evaluated as good and indicated as "○", and a case in which an appearance abnormality such as voids, wafer bulges, and wafer damage occurred was evaluated as poor and indicated as "x".
Note that the conditions for the CVD resistance test are as follows.
Equipment: Plasma CVD PD270STL (manufactured by Samco Co., Ltd.)
RF500W, internal pressure 40Pa
TEOS (tetraethyl orthosilicate): O ₂ = 20 sccm: 680 sccm

(4) Peelability test To test the peelability of the support, first, use a dicing frame to attach a dicing tape to the 50 μm thin wafer side of the wafer processed body that has undergone the CVD resistance test, and then apply vacuum suction to the surface of the dicing tape. and set it on the suction plate. Thereafter, the glass plate was peeled off by lifting one point of the glass plate with tweezers at room temperature. A case where a wafer of 50 μm could be peeled off without cracking was marked as “○”, and a case where an abnormality such as cracking occurred was evaluated as defective and marked as “×”.

(5) Washing removability test After completing the peelability test, a 200mm wafer (exposed to CVD resistance test conditions) mounted on a dicing frame via a dicing tape was placed in a spin coater with the temporary adhesive layer facing up. After setting the wafer and cleaning it by spraying the cleaning solvent shown in Table 1 for 5 minutes, the wafer was rinsed by spraying isopropyl alcohol while rotating the wafer. Thereafter, the appearance was observed and the presence or absence of the remaining resin layer was visually confirmed. Those in which no residual resin was observed were evaluated as good and indicated as "○", and those in which residual resin was observed were evaluated as poor and indicated in "x".

(6) Viscosity measurement The viscosity was measured using the following measuring equipment and conditions.
Equipment: HAAKE MARS II (manufactured by Thermo Scientific)
Heating rate: 10℃/min Measurement frequency: 1Hz
Measurement gap: 500μm
Measurement sample size: diameter 8mm

In this embodiment, a glass plate was used as a support in order to visually identify abnormalities after bonding the substrates, but a silicon substrate that does not transmit light, such as a wafer, can also be used.

Claims (5)

A temporary adhesive for a device substrate, comprising (A) a resin layer A containing a non-silicone thermoplastic resin having a glass transition temperature of 200° C. or higher, and (B) a resin layer B containing a silicone resin ,
A temporary adhesive for a device substrate, wherein the silicone resin has a viscosity of 7,000 Pa·s or more at 25°C, and a minimum viscosity of the silicone resin in the range of 80 to 150°C is 50 to 5,000 Pa·s. The temporary adhesive for a device substrate according to claim 1, wherein the non-silicone thermoplastic resin is at least one selected from polyimide, polyetherimide, polyether sulfone, aromatic polyether, aromatic polyester, and modified resins thereof. agent. The device substrate according to claim 1 or 2 , wherein the silicone resin has a viscosity of 10,000 Pa·s or more at 25°C, and a minimum viscosity of the silicone resin in the range of 80 to 150°C is 50 to 1,000 Pa·s. Temporary adhesive. A laminate comprising a device substrate, a temporary adhesive layer, and a support in this order, wherein the temporary adhesive layer is made of (A) a non-silicone-based heat treatment having a glass transition temperature of 200° C. or higher, in order from the device substrate side; It includes a resin layer A containing a plastic resin, and (B) a resin layer B containing a silicone resin, and the viscosity of the silicone resin at 25° C. is 7,000 Pa·s or more, and the viscosity of the silicone resin is 80 to A device substrate laminate having a minimum viscosity of 50 to 5,000 Pa·s in the range of 150°C . A method for manufacturing a device substrate laminate according to claim 4 , comprising:
(a) Forming a resin layer A containing a non-silicone thermoplastic resin having a glass transition temperature of 200° C. or higher on a device substrate, and forming a resin layer B containing a silicone resin on a support, and ( b) A method for manufacturing a device substrate laminate, including the step of bonding together a device substrate on which a resin layer A is formed and a support body on which a resin layer B is formed, with the resin layer A and the resin layer B interposed therebetween.