JP5592328B2 - Temporary adhesive composition and thin wafer manufacturing method using the same - Google Patents

Description

  The present invention relates to a temporary adhesive composition, mainly a temporary adhesive composition used in a manufacturing process that involves thinning a semiconductor wafer.

  Three-dimensional semiconductor mounting has become essential to achieve higher density and higher capacity. The three-dimensional semiconductor mounting technology is a semiconductor manufacturing technology in which one semiconductor chip is thinned and further laminated in multiple layers while being connected by a through silicon via (TSV). In order to realize this, it is necessary to reduce the thickness of the wafer on which the semiconductor circuit is formed by back grinding and further to form an electrode including TSV on the back surface. In the backside grinding process for silicon wafers, a protective tape is applied to the opposite side of the grinding surface to prevent wafer breakage during grinding, but this tape uses an organic resin film as the base material, while having flexibility, The strength and heat resistance are insufficient, and it is not suitable for performing the wiring layer forming process on the back surface.

  In view of this, a system that can sufficiently withstand back grinding, back electrode forming processes, and the like has been proposed by bonding a semiconductor wafer such as a silicon wafer to a support substrate such as silicon or glass via an adhesive. In this case, what is important is an adhesive for joining both substrates. This requires that the substrates can be joined without gaps, and must have sufficient durability to withstand subsequent processes, and finally, the thin wafer must be easily peeled from the support substrate. Thus, since it peels at the end, this adhesive material will be called a temporary adhesive material.

  Conventionally known temporary adhesives and peeling methods include a technique for peeling an adhesive layer from a support substrate by irradiating an adhesive containing a light-absorbing substance with high-intensity light and decomposing the adhesive layer ( Patent Document 1) and a technique (Patent Document 2) that uses a hydrocarbon-based heat-meltable compound as an adhesive and performs bonding / peeling in a heat-melted state have been proposed. From the viewpoint of materials, cycloolefin polymers (Patent Documents 3 and 4), use of silicone resins (Patent Document 5), and the like have been proposed. However, none of the resins has reached a characteristic that can be used as a temporary adhesive.

JP 2004-64040 A JP 2006-328104 A International Publication No. 2010/147103 International Publication No. 2010/143510 US Pat. No. 7,541,264

  This invention is made | formed in view of the said situation, and it aims at providing the temporary adhesive material composition which has the characteristic which can be used as a temporary adhesive material.

（式（１）中のＲ^１は互いに同一又は異種の脂肪族不飽和結合を有さない一価の有機基であり、ｓは０〜２の整数であり、ｉは０又は１であり、ｊは１〜４の整数である。）

（式（２）中のＡ^１〜Ａ^４は、それぞれ独立して、水素原子、ハロゲン原子、炭素数１〜１０のアルキル基、アルケニル基、シクロアルキル基、アリール基、アルコキシ基、アリーロキシ基及びハロゲン化炭化水素基から選ばれる置換基、又はオキセタニル基及びアルコキシカルボニル基から選ばれる極性を有する置換基である。あるいは、Ａ^１とＡ^２又はＡ^１とＡ^３とが、それぞれが結合する炭素原子と共に脂環構造、芳香環構造、カルボンイミド基及び酸無水物基のいずれかを形成してもよい。ｋは０又は１である。） In order to solve the above problems, the present invention provides:
(A) Addition polymerization of a cyclic olefin functional siloxane represented by the following formula (1) or a cyclic olefin functional siloxane represented by the following formula (1) and a cyclic olefin compound represented by the following formula (2) An addition polymer obtained by any one of the addition polymerizations in which the proportion of structural units derived from the following formula (1) is 5 to 100 mol% in the addition polymer, and GPC using THF as a solvent. A siloxane cyclic olefin addition polymer having a polystyrene-reduced number average molecular weight (Mn) of 10,000 to 2,000,000,
(B) A temporary adhesive composition comprising a hydrocarbon-based organic solvent is provided.

(R ¹ in Formula (1) is a monovalent organic group that does not have the same or different aliphatic unsaturated bond, s is an integer of 0 to 2, i is 0 or 1, j is an integer of 1 to 4.)

(A ^{1 to} A ⁴ in the formula (2) are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkenyl group, a cycloalkyl group, an aryl group, an alkoxy group, an aryloxy group, and A substituent selected from a halogenated hydrocarbon group, or a substituent having a polarity selected from an oxetanyl group and an alkoxycarbonyl group, or carbon to which A ¹ and A ² or A ¹ and A ³ are bonded to each other. Any of an alicyclic structure, an aromatic ring structure, a carbonimido group, and an acid anhydride group may be formed together with the atoms, and k is 0 or 1.)

  Such a temporary adhesive composition has excellent characteristics sufficient to withstand use as a temporary adhesive.

The component (B) is preferably a hydrocarbon organic solvent having a boiling point of 100 to 240 ° C.
If the solvent has the boiling point, the safety is high and the composition can be spin-coated, so that the handling property is further improved.

The present invention is also a method for manufacturing a thin wafer,
(I) An adhesive layer is formed from at least one of the circuit forming surface and the support substrate surface of the wafer having a circuit forming surface and a circuit non-forming surface by the temporary adhesive composition of the present invention, Bonding the circuit forming surface of the wafer and the support substrate,
(II) grinding the non-circuit-formed surface of the wafer bonded to the support substrate;
(III) a step of peeling the ground wafer from the support substrate;
(IV) A method for producing a thin wafer, comprising a step of removing an adhesive layer remaining on a circuit forming surface of the peeled wafer.

  Since the thin wafer manufacturing method of the present invention uses the composition of the present invention having excellent characteristics as a temporary adhesive, the thin wafer can be efficiently manufactured.

As described above, according to the composition of the present invention, the adhesiveness when bonding the wafer and the support substrate, the durability against the process such as grinding, and the last when the thinned wafer is peeled from the support substrate. There is provided a temporary adhesive material having excellent characteristics such as peelability, which can withstand use as a temporary adhesive material. In addition, the handleability can be further improved by the solvent used, which is industrially excellent.
Furthermore, if a thin wafer is manufactured using this, it has sufficient durability to withstand processes such as back grinding, so that the wafer does not suffer from defects such as cracks and defects, When peeling from the wafer, it can be easily peeled off. Thereby, it becomes possible to manufacture a thin wafer efficiently.

Hereinafter, the present invention will be described in more detail.
As described above, conventionally known temporary adhesives mainly used in the manufacturing process of a semiconductor wafer accompanied by a reduction in thickness have not reached a characteristic that can be used as a temporary adhesive.

  Thus, as a result of investigations by the present inventors, it was found that a system using a specific silicone-modified norbornene resin becomes a composition suitable as a temporary adhesive, and the present invention has been completed.

（式（１）中のＲ^１は互いに同一又は異種の脂肪族不飽和結合を有さない一価の有機基であり、ｓは０〜２の整数であり、ｉは０又は１であり、ｊは１〜４の整数である。）

（式（２）中のＡ^１〜Ａ^４は、それぞれ独立して、水素原子、ハロゲン原子、炭素数１〜１０のアルキル基、アルケニル基、シクロアルキル基、アリール基、アルコキシ基、アリーロキシ基及びハロゲン化炭化水素基から選ばれる置換基、又はオキセタニル基及びアルコキシカルボニル基から選ばれる極性を有する置換基である。あるいは、Ａ^１とＡ^２又はＡ^１とＡ^３とが、それぞれが結合する炭素原子と共に脂環構造、芳香環構造、カルボンイミド基及び酸無水物基のいずれかを形成してもよい。ｋは０又は１である。） That is, the temporary adhesive composition of the present invention is
(A) Addition polymerization of a cyclic olefin functional siloxane represented by the following formula (1) or a cyclic olefin functional siloxane represented by the following formula (1) and a cyclic olefin compound represented by the following formula (2) An addition polymer obtained by any one of the addition polymerizations in which the proportion of structural units derived from the following formula (1) is 5 to 100 mol% in the addition polymer, and GPC using THF as a solvent. A siloxane cyclic olefin addition polymer having a polystyrene-reduced number average molecular weight (Mn) of 10,000 to 2,000,000,
(B) It contains hydrocarbon organic solvent.

(Formula (1) R ¹ in is a monovalent organic group having no aliphatic unsaturated bonds of the same or different from each other, s is an integer of 0 to 2, i is 0 or 1, j is an integer of 1 to 4.)

(A ^{1 to} A ⁴ in the formula (2) are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkenyl group, a cycloalkyl group, an aryl group, an alkoxy group, an aryloxy group, and A substituent selected from a halogenated hydrocarbon group, or a substituent having a polarity selected from an oxetanyl group and an alkoxycarbonyl group, or carbon to which A ¹ and A ² or A ¹ and A ³ are bonded to each other. Any of an alicyclic structure, an aromatic ring structure, a carbonimido group, and an acid anhydride group may be formed together with the atoms, and k is 0 or 1.)

The formula (1) represented by a cyclic olefin functional siloxanes with _{- (CH} ²⁾ by ^{_{j -SiR 1 s (OSiR 1 3}} ) 3-s group, especially solubility improved in the solvent to be used for spin-coating To do.
As a result, the composition of the present invention has excellent properties such as adhesion, detergency, peelability, grinder resistance, heat resistance, chemical resistance, and the like that can withstand use as a temporary adhesive. It becomes.

Hereinafter, the present invention will be described in more detail.
<Temporary adhesive composition>
[(A) component]
The siloxane cyclic olefin addition polymer which is the component (A) of the composition of the present invention is addition-polymerized with the cyclic olefin functional siloxane represented by the following formula (1) or represented by the following formula (1). It is produced by addition polymerization of a cyclic olefin functional siloxane and a cyclic olefin compound represented by the following formula (2).

In said formula (1), s is an integer of 0-2, i is 0 or 1, and j is an integer of 1-4.
R ¹ is a monovalent organic group having no aliphatic unsaturated bond that may be the same or different from each other, preferably an unsubstituted or substituted monovalent hydrocarbon group having 1 to 10 carbon atoms, for example, Alkyl groups such as methyl group, ethyl group, n-propyl group, butyl group and pentyl group; aryl groups such as phenyl group, tolyl group and xylyl group; aralkyl groups such as 2-phenylethyl group and 3-phenylpropyl group; And groups in which one or more hydrogen atoms of these groups are substituted with a halogen atom such as a fluorine atom, a chlorine atom or a bromine atom.

Examples of the cyclic olefin functional siloxane represented by the above formula (1) include the following compounds, but the present invention is not limited to these specific examples. Here, Me represents a methyl group and Ph represents a phenyl group (hereinafter the same).

  The cyclic olefin functional siloxane represented by the above formula (1) may be used alone or in combination of two or more.

On the other hand, in the above formula (2), k is 0 or 1.
A ^{1 to} A ⁴ are each independently a hydrogen atom; a halogen atom such as a fluorine atom, a chlorine atom or a bromine atom; a methyl group having 1 to 10 carbon atoms, an ethyl group, a propyl group, an isopropyl group, a butyl group, or isobutyl. Group, tert-butyl group, pentyl group, neopentyl group, hexyl group, octyl group, nonyl group, decyl group and other alkyl groups; vinyl group, allyl group, butenyl group, hexenyl group and other alkenyl groups; cyclohexyl group and other cyclo groups Alkyl group; aryl group such as phenyl group, tolyl group, xylyl group, naphthyl group; alkoxy group such as methoxy group, ethoxy group, propoxy group; aryloxy group such as phenoxy group; 3,3,3-trifluoropropyl group, Halogens such as 2- (perfluorobutyl) ethyl group, 2- (perfluorooctyl) ethyl group, p-chlorophenyl group Having a polarity selected from an alkoxycarbonyl group having 1 to 10 carbon atoms, preferably 1 to 6 carbon atoms, preferably a group selected from a fluorinated hydrocarbon group, or an oxetanyl group, a methoxycarbonyl group, a tert-butoxycarbonyl group, etc. It is a substituent.

Alternatively, A ¹ and A ² or A ¹ and A ³ may form an alicyclic structure, an aromatic ring structure, a carbonimide group, or an acid anhydride group together with the carbon atoms to which they are bonded.
In this case, examples of the alicyclic structure in the above formula (2) include those having 4 to 10 carbon atoms, and examples of the aromatic ring structure include those having 6 to 12 carbon atoms. Examples of these structures are as follows.

Examples of the state in which these are bonded to the norbornene ring are as follows. In the above formula (2), the case where k = 0 is shown.

Although the following compounds can be illustrated as a cyclic olefin compound represented by the said Formula (2), this invention is not limited to these specific examples.
Bicyclo [2.2.1] hept-2-ene, 5-methyl-bicyclo [2.2.1] hept-2-ene, 5-ethyl-bicyclo [2.2.1] hept-2-ene, 5-propyl-bicyclo [2.2.1] hept-2-ene, 5-butyl-bicyclo [2.2.1] hept-2-ene, 5-pentyl-bicyclo [2.2.1] hept- 2-ene, 5-hexyl-bicyclo [2.2.1] hept-2-ene, 5-octyl-bicyclo [2.2.1] hept-2-ene, 5-decyl-bicyclo [2.2. 1] Hept-2-ene, 5-phenyl-bicyclo [2.2.1] hept-2-ene, 5-vinyl-bicyclo [2.2.1] hept-2-ene, 5-allyl-bicyclo [ 2.2.1] Hept-2-ene, 5-isopropylidene-bicyclo [2.2.1] Put-2-ene, 5-cyclohexyl-bicyclo [2.2.1] hept-2-ene, 5-fluoro-bicyclo [2.2.1] hept-2-ene, 5-chloro-bicyclo [2. 2.1] hept-2-ene, methyl bicyclo [2.2.1] hept-5-ene-2-carboxylate, ethyl bicyclo [2.2.1] hept-5-ene-2-carboxylate, Bicyclo [2.2.1] hept-5-ene-2-carboxylate, 2-methyl-bicyclo [2.2.1] hept-5-ene-2-carboxylate, 2-methyl-bicyclo [ 2.2.1] ethyl hept-5-ene-2-carboxylate, 2-methyl-bicyclo [2.2.1] propyl propyl-5-ene-2-carboxylate, 2-methyl-bicyclo [2. 2.1] Trifuro of hept-5-ene-2-carboxylic acid Ethyl, 2-methyl-bicyclo [2.2.1] hept-2-enyl acetate, 2-methyl-bicyclo [2.2.1] hept-5-enyl acrylate, 2-methyl-bicyclo methacrylate [ 2.2.1] hept-5-enyl, bicyclo [2.2.1] hept-5-ene-2,3-dicarboxylate, tricyclo [4.3.0.1 ^2,5 ] deca-3 -Ene, tetracyclo [4.4.0.1 ^2,5 . 1 ^7,10 ] dodec-3-ene and the like. These may be used alone or in combination of two or more.

  The charge ratio of the cyclic olefin functional siloxane represented by the above formula (1) and the cyclic olefin compound represented by the above formula (2) takes into consideration the gas permeation characteristics of the obtained cyclic olefin addition polymer of the present invention. And it is preferable to use it so that the structural unit derived from the said Formula (1) in the obtained polymer may be 5-100 mol% in total, Preferably it is 10-100 mol%.

The siloxane cyclic olefin addition polymer (A) component of the composition of the present invention is an addition polymerization of a cyclic olefin functional siloxane represented by the above formula (1) or a cyclic olefin functional siloxane of the above formula (1). And a cyclic olefin compound represented by the above formula (2). In addition polymerization, it is preferable to use a multicomponent catalyst containing the following compounds (C1), (C2) and (C3).
[Compound (C1)]
Zero-valent palladium compound.
[Compound (C2)]
Ionic boron compounds.
[Compound (C3)]
A phosphine compound having a substituent selected from an alkyl group having 3 to 6 carbon atoms, a cycloalkyl group, and an aryl group.

  Conventional cycloolefin compound addition polymerization catalysts are selected from Group 8 elements, Group 9 elements and Group 10 elements of the periodic table, for example, iron (Fe), cobalt (Co), nickel (Ni) , Transition metal complexes having ruthenium (Ru), rhodium (Rh), palladium (Pd), platinum (Pt) and the like as a central metal. However, in order to obtain the cyclic olefin addition polymer of the present invention having both excellent physical properties, the reactivity to the cyclic olefin functional siloxane represented by the above formula (1) is high, and the resulting polymer is It is necessary to be a high molecular weight substance, and in this respect, a combination of a compound (C1) having a specific ligand with palladium as a central metal, an ionic boron compound (C2), and a phosphine compound (C3) Preferably used.

  Further, the compound (C1) having palladium as a central metal is preferably a zero-valent palladium complex from the viewpoint of polymerization activity, molecular weight controllability, and handleability.

（式（３）中のＲ^１、ｉ、ｊ及びｓは上記式（１）と同じである。） The cyclic olefin addition polymer of the present invention thus obtained is formed by addition polymerization using the cyclic olefin functional siloxane represented by the above formula (1) as a monomer. Contains the repeat unit indicated.

(R ¹ , i, j and s in the formula (3) are the same as in the above formula (1).)

（式（４）中のＡ^１〜Ａ^４及びｋは上記式（２）と同じである。） Moreover, when the cyclic olefin compound represented by the above formula (2) is used, the cyclic olefin addition polymer of the present invention undergoes addition polymerization using the cyclic olefin compound represented by the above formula (2) as a monomer. And a repeating unit represented by the following formula (4).

(A ^{1 to} A ⁴ and k in the formula (4) are the same as the above formula (2).)

Here, the repeating unit represented by the above formula (4) represents a 2,3-addition structural unit when, for example, k is 0 and A ^{1 to} A ⁴ are all hydrogen atoms. And a cyclic olefin compound represented by (2) may be included as a 2,7 addition structural unit by addition polymerization. The same applies to the repeating unit represented by the above formula (3).

  The molecular weight of the cyclic olefin addition polymer of the present invention is an important factor involved in the development of excellent physical properties. The number average molecular weight (Mn) in terms of polystyrene measured by gel permeation chromatography (GPC) using THF as a solvent is 10,000 to 2,000,000, preferably 20,000 to 500,000. The ratio of the weight average molecular weight (Mw) to the number average molecular weight (Mn) (dispersity: Mw / Mn) is preferably 1.0 to 6.0, more preferably 1.0 to 5.5. .

  When the number average molecular weight is less than 10,000, when it is used as a thin film, film or sheet, it becomes brittle and easily cracked, and the film strength that can withstand actual use cannot be obtained. On the other hand, when the number average molecular weight exceeds 2,000,000, molding processability and solubility in solvents decrease, solution viscosity increases, and handling becomes difficult. Moreover, when the ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) exceeds 6.0, it may be inferior in terms of cracking and brittleness.

  In the present invention, when a multi-component catalyst comprising the above compounds (C1), (C2) and (C3) is used, the number average molecular weight (Mn) is 10,000 to 2,000,000, and the weight average molecular weight. A cyclic olefin addition polymer having a narrow molecular weight distribution in which the ratio (Mw / Mn) of (Mw) to the number average molecular weight (Mn) is in the range of 1.0 to 6.0 can be easily obtained. For this reason, when it is used as a thin film such as a coating film, a film or a sheet, it is excellent in terms of cracking and brittleness.

[Component (B)]
Component (B) is a hydrocarbon organic solvent that dissolves the siloxane cyclic olefin addition polymer of component (A) and can form a thin film having a thickness of 1 to 200 μm by a known coating film forming method such as spin coating. Those are preferred. A more preferable film thickness is 5 to 180 μm, and further preferably 30 to 150 μm.

As the organic solvent for dissolving the component (A), those other than polar solvents such as ketones, esters and alcohols can be used, and non-aromatic hydrocarbons are preferred.
Specific examples include pentane, hexane, cyclopentane, cyclohexane, methylcyclohexane, octane, isooctane, decane, undecane, isododecane, limonene, pinene, Isopar E, Isopar G, Isopar H, Isosol 300, etc., and mixtures thereof But it ’s okay.

Among these, as a temporary adhesive composition that can be spin-coated and has high safety, the boiling point is preferably 100 to 240 ° C. That is, octane, isooctane, decane, isodecane, dodecane, isododecane, limonene, and isopar series are suitable.
A boiling point of 100 ° C. or higher is preferable because the flash point of the hydrocarbon-based organic solvent is increased. Hydrocarbon organic solvents having a boiling point of 240 ° C. or less are liable to volatilize even by heating and drying after coating, and hardly stay in the film. Therefore, even when the temporary adhesive composition is exposed to a high temperature in the heating process after bonding the substrates, it is preferable because the formation of bubbles at the bonding interface can be suppressed.

[Other ingredients]
In addition to the components (A) and (B), a known surfactant may be added to the temporary adhesive composition of the present invention in order to improve applicability. Specifically, nonionic ones are preferable, and examples thereof include fluorine surfactants, perfluoroalkyl polyoxyethylene ethanol, fluorinated alkyl esters, perfluoroalkylamine oxides, fluorine-containing organosiloxane compounds, and the like.

Further, the temporary adhesive composition of the present invention can be blended with a known antioxidant to improve oxidation stability.
Antioxidants include 2,6-di-t-butyl-4-methylphenol, 4,4′-thiobis- (6-t-butyl-3-methylphenol), 1,1′-bis- (4 -Hydroxyphenyl) cyclohexane, 2,5-di-t-butylhydroquinone, pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl)] propionate, etc. , Tris (4-methoxy-3,5-diphenyl) phosphite, tris (nonylphenyl) phosphite, tris (2,4-di-t-butylphenyl) phosphite, bis (2,4-di-t- Phosphorus type such as (butylphenyl) pentaerythritol diphosphite, and also thioether type and lactone type compounds.

  Among these compounds, those having a decomposition temperature (5% mass reduction temperature) of 250 ° C. or more are preferable. Moreover, the compounding quantity of these antioxidants is the range of 0.05-5.0 mass parts with respect to 100 mass parts of cyclic olefin addition polymers of this invention.

<Manufacturing method of thin wafer>
The present invention is also a method for manufacturing a thin wafer,
(I) An adhesive layer is formed by using the temporary adhesive composition of the present invention on at least one of the circuit forming surface and the support substrate surface of a wafer having a circuit forming surface and a circuit non-forming surface. Bonding the circuit forming surface of the wafer and the support substrate,
(II) grinding the non-circuit-formed surface of the wafer bonded to the support substrate;
(III) a step of peeling the ground wafer from the support substrate;
(IV) A method for producing a thin wafer, comprising a step of removing an adhesive layer remaining on a circuit forming surface of the peeled wafer.

  The method for producing a thin wafer of the present invention is characterized in that the temporary adhesive composition described above is used as an adhesive layer between a wafer having a semiconductor circuit and a support substrate used for reducing the thickness of the wafer. The thickness of the thin wafer obtained by the production method of the present invention is typically 300 to 5 μm, more typically 100 to 10 μm.

[Step (I)]
In step (I), an adhesive layer is formed on at least one of the circuit forming surface of the wafer and the surface of the support substrate with the temporary adhesive composition of the present invention, and the circuit forming surface of the wafer and the support are supported via the adhesive layer. This is a step of bonding the substrate. The wafer is a wafer in which one surface is a circuit formation surface and the other surface is a circuit non-formation surface.

  A wafer to which the present invention is applicable is usually a semiconductor wafer. Examples of the wafer include not only a silicon wafer but also a germanium wafer, a gallium-arsenic wafer, a gallium-phosphorus wafer, a gallium-arsenic-aluminum wafer, and the like. The wafer in step (I) is a wafer before being back-ground in step (II), and the thickness thereof is not particularly limited, but is typically 800 to 600 μm, more typically 775 to 625 μm. is there.

  As the support substrate, a silicon wafer, a glass wafer, a quartz wafer, or the like can be used. In the present invention, it is not necessary to irradiate the adhesive layer with radiant energy rays through the support substrate, and the light transmittance of the support substrate is unnecessary.

  The adhesive layer is formed by, for example, spin coating using the temporary adhesive composition of the present invention. The adhesive layer is formed on one or both of the wafer and the support substrate, and the wafer is bonded to the support substrate through the adhesive layer thus formed. When the adhesive layer is formed on the wafer, it is formed on the circuit forming surface of the wafer.

  The adhesive layer formed using the temporary adhesive composition of the present invention is softened by heating. The temperature range in which the resin in the adhesive layer is softened is 80 to 320 ° C., preferably 100 to 300 ° C., more preferably 120 to 260 ° C., and both substrates (ie, wafer and supporting substrate) under reduced pressure at this temperature. Is bonded uniformly to form a bonded substrate in which the wafer is bonded to the support substrate. After the resin in the adhesive layer is partially softened or melted by heating the chamber in which both substrates are installed to the above temperature range under reduced pressure, bubbles are generated at the interface by bringing both substrates into contact and thermocompression bonding. A uniform bonding interface can be formed without pinching. When the wafer is bonded to the support substrate via the adhesive layer, the temperature of the support substrate is preferably within the above temperature range. Since the resin in the adhesive layer is sufficiently softened at these bonding temperatures, the unevenness existing on the surface to be bonded to the wafer can be embedded without a gap. For example, an 8-inch wafer (diameter: 200 mm) can be bonded at a load of 20 kN or less, preferably 10 kN or less, more preferably 7 kN or less.

  Examples of the wafer bonding apparatus include commercially available wafer bonding apparatuses such as EVG520IS and 850TB manufactured by EVG; XBC300 manufactured by SUSS.

[Step (II)]
In the step (II), the circuit non-formation surface of the wafer bonded to the support substrate is ground, that is, the wafer back surface side of the laminated substrate bonded in the step (I) is ground to reduce the thickness of the wafer. It is a process to do. There is no particular limitation on the method of grinding the back surface of the wafer, and a known grinding method is adopted. The grinding is preferably performed while cooling the wafer and the grindstone with water. Examples of the apparatus for grinding the back surface of the wafer include DAG-810 (trade name) manufactured by DISCO Corporation.

[Processing process]
In the manufacturing method of the thin wafer of this invention, a process process can be included after the above-mentioned grinding process (II) and before the peeling process (III) mentioned later. The processing step is a step of processing a wafer having a non-circuit-formed surface ground, that is, a wafer thinned by back surface grinding. This process includes various processes used at the wafer level, and examples include electrode formation, metal wiring formation, and protective film formation. More specifically, metal sputtering for forming electrodes, etc., wet etching for etching a metal sputtering layer, application of a resist to form a mask for forming a metal wiring, pattern formation by exposure and development, resist peeling Conventionally known processes such as dry etching, metal plating formation, silicon etching for TSV formation, and formation of an oxide film on the silicon surface can be mentioned.

[Step (III)]
Step (III) is a step of peeling the ground wafer from the supporting substrate, that is, a step of peeling the thinned wafer from the supporting substrate after various processing and before dicing. As a peeling method, mainly the method of separating both substrates by sliding the wafer and the supporting substrate in opposite directions while heating, while fixing one of the laminated substrates horizontally, while heating Many proposals have been made, such as a method of lifting the other substrate at a certain angle from the horizontal direction, a method of attaching a protective film to the ground surface of the ground wafer, and peeling the wafer and the protective film by a peel method. ing.
Any of these peeling methods can be applied to the present invention, but a horizontal slide peeling method is more suitable.

The laminated substrate is heated, and the wafer is peeled from the support substrate by applying a force in a state where the adhesive layer is melted or softened. The heating temperature is preferably 50 to 300 ° C, more preferably 60 to 230 ° C, and even more preferably 70 to 220 ° C in the adhesive layer used in the present invention.
As an apparatus for performing such peeling, EVG850DB of EVG, XBC300 of SUSS, etc. are mentioned (all are trade names).

[Step (IV)]
Step (IV) is a step of removing the adhesive layer remaining on the circuit forming surface of the peeled wafer. The remaining adhesive layer can be removed, for example, by washing the wafer.
In the step (IV), any cleaning liquid that dissolves the resin in the adhesive layer can be used. Specifically, the component (B) hydrocarbon organic solvent of the above composition can be used. is there. These solvents may be used alone or in combination of two or more.

Moreover, when it is difficult to remove, bases and acids may be added to the solvent. Examples of bases that can be used include amines such as ethanolamine, diethanolamine, triethanolamine, triethylamine, and ammonia, and ammonium salts such as tetramethylammonium hydroxide. As the acids, organic acids such as acetic acid, oxalic acid, benzenesulfonic acid, and dodecylbenzenesulfonic acid can be used. The addition amount of these bases and acids is 0.01 to 10% by mass, preferably 0.1 to 5% by mass.
In order to improve the removability of the residue, an existing surfactant may be added.

  As a cleaning method, a method of performing cleaning with a paddle using the above liquid, a cleaning method of spraying, and a method of immersing in a cleaning liquid tank are possible. The temperature is 10-80 ° C, preferably 15-65 ° C.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further more concretely, this invention is not limited to these Examples. In the following examples, Me represents a methyl group, Ph represents a phenyl group, and Cy represents a cyclohexyl group.

The molecular weight, molecular weight distribution, and monomer composition ratio of the polymer were evaluated by the following methods.
1) The weight average molecular weight (Mw), number average molecular weight (Mn), and molecular weight distribution (Mw / Mn) of the polymers obtained in the examples were determined using polystyrene as a standard substance by GPC using THF as a solvent. .
2) The composition ratio of norbornene derivative / norbornene in the copolymer was determined from the integral ratio of the peaks obtained by ¹ H-NMR.

[Preparation of catalyst solution]
Bis (dibenzylideneacetone) palladium [Pd (C ₁₇ H ₁₄ O) ₂ ] 0.0057 g (1.0 × 10 ⁻⁵ mol), triphenylcarbenium tetrakis (pentafluorophenyl) borate {[Ph ₃ C] [ B (C ₆ F ₅ ) ₄ ]} 0.0092 g (1.0 × 10 ⁻⁵ mol) and tricyclohexylphosphine (PCy ₃ ) 0.0028 g (1.0 × 10 ⁻⁵ mol) were each dissolved in 10 ml of toluene. To prepare a catalyst solution.

[Synthesis Example 1]
In a glass container purged with nitrogen, 107.4 g (0.4 mol) of monomer a represented by the following formula (6) was dissolved in 600 ml of toluene. The prepared catalyst solution was added thereto, and a polymerization reaction was performed at 50 ° C. for 1.5 hours.

After completion of the reaction, the polymer was precipitated by pouring into a large amount of methanol, washed by filtration, and dried under reduced pressure at 120 ° C. for 12 hours to obtain 75 g (yield 70%) of polymer P1.
The molecular weight of the obtained polymer P1 as measured by GPC was Mn = 85,000 and the molecular weight distribution Mw / Mn = 3.6. The obtained polymer P1 was prepared to be a 20% solution of isododecane and used as a resin solution (X).

[Synthesis Example 2]
In a glass container substituted with nitrogen, monomer a50.1 g (0.19 mol) represented by the above formula (6) and monomer b7.5 g (0.08 mol) represented by the following formula (7) ) Was dissolved in 500 ml of toluene. The prepared catalyst solution was added thereto, and a polymerization reaction was performed at 40 ° C. for 1 hour.

After the completion of the reaction, the polymer was precipitated by pouring into a large amount of methanol, washed by filtration, and dried under reduced pressure at 120 ° C. for 12 hours to obtain 31 g (yield 53%) of polymer P2.
The molecular weight of the obtained polymer P2 as measured by GPC was Mn = 55,000 and the molecular weight distribution Mw / Mn = 3.9. ^{From the 1} H-NMR spectrum, it was confirmed that the composition ratio of the structure derived from monomer a and the structure derived from monomer b in the polymer was a / b = 70/30 (mol / mol). . The obtained polymer P2 was prepared so as to be a solution of Isopar G 20% and used as a resin solution (Y).

[Synthesis Example 3]
In a glass container substituted with nitrogen, 96 g (0.28 mol) of monomer c represented by the following formula (8) and 11.3 g (0.12 mol) of monomer b represented by the above formula (7) Dissolved in 1500 ml of toluene. The prepared catalyst solution was added thereto, and a polymerization reaction was carried out at 40 ° C. for 0.5 hour.

After the completion of the reaction, the polymer was precipitated by pouring into a large amount of methanol, washed by filtration, and dried under reduced pressure at 120 ° C. for 12 hours to obtain 55 g (yield 51%) of polymer P3.
The molecular weight of the obtained polymer P3 as measured by GPC was Mn = 32,000 and the molecular weight distribution Mw / Mn = 4.2. ^{From the 1} H-NMR spectrum, it was confirmed that the composition ratio of the structure derived from monomer c and the structure derived from monomer b in the polymer was c / b = 70/30 (mol / mol). . The obtained polymer P3 was prepared so as to be a solution of Isopar G 20% and used as a resin solution (Z).

[Example 1-3]
Using a resin solution (X, Y, Z) on the circuit forming surface of an 8-inch silicon wafer (diameter: 200 mm, thickness: 725 μm) on which a circuit is formed on one side, an adhesive layer having a film thickness described in Table 1 by spin coating Formed. After confirming the appearance in the following manner, an 8-inch glass substrate (glass wafer) is used as a support substrate, and the support substrate and a silicon wafer having an adhesive layer are bonded at the bonding temperatures shown in Table 1 in a vacuum bonding apparatus. The laminated substrate was produced by bonding. Then, the following test was done. In addition, the solvent resistance was evaluated by separately preparing an experimental substrate. The results are shown in Table 1.

[appearance]
The coated film after spin coating is dried on a hot plate at 150 ° C./2 minutes and then at 200 ° C./2 minutes. After the solvent in the coated film is completely distilled off, the appearance of the coated film is visually checked and touched Tack feeling was confirmed. Those without cracks and tack were judged as good (◯), and those with cracks and / or tack were judged as bad (x).

[Adhesion test]
Eight-inch wafer bonding was performed using a wafer bonding apparatus 520IS manufactured by EVG. The bonding temperature was as shown in Table 1, the pressure in the chamber at the time of bonding was 10 ⁻³ mbar or less, and the load was 5 kN. After bonding, the adhesion state of the interface after cooling to room temperature was visually confirmed, and a case where no abnormality such as bubbles at the interface did not occur was indicated as ◯, and a case where abnormality occurred was indicated as ×.

[Back grinding resistance test]
Using a grinder (manufactured by DAG810 DISCO), backside grinding of the silicon wafer after bonding was performed. After grinding to a final substrate thickness of 50 μm, the optical microscope was examined for abnormalities such as cracks and peeling. A case where no abnormality has occurred is indicated by ◯, and a case where abnormality has occurred is indicated by ×.

[Heat resistance test]
The laminated substrate after the back grinding of the silicon wafer was placed in a 250 ° C. oven in a nitrogen atmosphere for 2 hours and then examined for abnormal appearance after heating on a 270 ° C. hot plate for 10 minutes. A case where an appearance abnormality does not occur is indicated by ○, and a case where an appearance abnormality occurs is indicated by ×.

[Peelability test]
Using the EVG850DB manufactured by EVG, the wafer and the supporting substrate were slid in the opposite directions while separating the laminated substrate after the heat resistance test was performed at 220 ° C. and separated. Thereafter, the circuit forming surface of the wafer was cleaned with Isopar G. The circuit-formed surface of the wafer after cleaning was visually observed, and those in which no residue was observed were judged as good (◯), and those in which the residue was found were judged as bad (x).

[Solvent resistance test]
Using a resin solution (X, Y, Z) on a 6-inch wafer (diameter 150 mm), a 30 μm-thick coating film was formed by spin coating, and after 150 ° C./2 minutes, it was dried by heating at 200 ° C./2 minutes. Then, this coating film was immersed in a propylene glycol monomethyl ether acetate (PGMEA) solution at 25 ° C. for 10 minutes and visually checked for dissolution. Those in which dissolution of the resin was not observed were evaluated as good (◯), and those in which the resin was dissolved were determined as poor (×).

  As shown in Table 1, both Examples 1 to 3 using the temporary adhesive composition of the present invention are excellent in adhesion when bonding a silicon wafer and a glass wafer (support substrate), and have resistance to back grinding. It had heat resistance and solvent resistance, and was excellent in releasability when peeling the silicon wafer from the support substrate.

  The present invention is not limited to the above embodiment. The above-described embodiment is an exemplification, and the present invention has substantially the same configuration as the technical idea described in the claims of the present invention, and any device that exhibits the same function and effect is the present invention. It is included in the technical scope of the invention.

Claims (3)

(A) Addition polymerization of a cyclic olefin functional siloxane represented by the following formula (1) or a cyclic olefin functional siloxane represented by the following formula (1) and a cyclic olefin compound represented by the following formula (2) An addition polymer obtained by any one of the addition polymerizations in which the proportion of structural units derived from the following formula (1) is 5 to 100 mol% in the addition polymer, and GPC using THF as a solvent. A siloxane cyclic olefin addition polymer having a polystyrene-reduced number average molecular weight (Mn) of 10,000 to 2,000,000,
(B) A temporary adhesive composition comprising a hydrocarbon-based organic solvent.

(R ¹ in Formula (1) is a monovalent organic group that does not have the same or different aliphatic unsaturated bond, s is an integer of 0 to 2, i is 0 or 1, j is an integer of 1 to 4.)

(A ^{1 to} A ⁴ in the formula (2) are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkenyl group, a cycloalkyl group, an aryl group, an alkoxy group, an aryloxy group, and A substituent selected from a halogenated hydrocarbon group, or a substituent having a polarity selected from an oxetanyl group and an alkoxycarbonyl group, or carbon to which A ¹ and A ² or A ¹ and A ³ are bonded to each other. Any of an alicyclic structure, an aromatic ring structure, a carbonimido group, and an acid anhydride group may be formed together with the atoms, and k is 0 or 1.)   The temporary adhesive composition according to claim 1, wherein the component (B) is a hydrocarbon-based organic solvent having a boiling point of 100 to 240 ° C. A method for manufacturing a thin wafer,
(I) An adhesive layer is formed by using the temporary adhesive composition according to claim 1 or 2 on at least one of the circuit forming surface and the support substrate surface of a wafer having a circuit forming surface and a circuit non-forming surface. Bonding the circuit forming surface of the wafer and the support substrate through the adhesive layer;
(II) grinding the non-circuit-formed surface of the wafer bonded to the support substrate;
(III) a step of peeling the ground wafer from the support substrate;
(IV) A method for producing a thin wafer, comprising a step of removing an adhesive layer remaining on a circuit forming surface of the peeled wafer.