JP7833546B2 - Method for manufacturing a substrate laminate and substrate laminate - Google Patents

Description

This disclosure relates to a method for manufacturing a substrate laminate and to a substrate laminate.

As electronic devices become smaller, lighter, and more powerful, there is a growing demand for higher integration of semiconductor chips and other components. However, miniaturizing circuits alone is insufficient to meet this demand. Therefore, in recent years, methods have been proposed to achieve high integration by stacking multiple semiconductor substrates (wafers), semiconductor chips, etc., vertically to create a multilayer three-dimensional structure. Methods for stacking semiconductor substrates (wafers), semiconductor chips, etc. (hereinafter sometimes referred to as "semiconductor substrates, etc.") include direct bonding of substrates and methods using adhesives (for example, Patent Documents 1 to 3).

Patent Document 1: Japanese Unexamined Patent Publication No. 4-132258 Patent Document 2: Japanese Unexamined Patent Publication No. 2010-226060 Patent Document 3: Japanese Unexamined Patent Publication No. 2016-47895

Direct bonding has the problem of easily generating voids due to minute irregularities and particles caused by wiring on the substrate surface. As a method for laminating semiconductor substrates, a method of bonding inorganic materials such as silicon dioxide provided on the substrate is also conceivable. However, this method of bonding inorganic materials on the substrate also suffers from the same problem as direct bonding: it is prone to generating voids.

On the other hand, when joining using an adhesive, the adhesive is applied to the substrate surface, then dried to a semi-cured state, and then the substrates are bonded together. In this case, to suppress the generation of voids, it is conceivable to apply the adhesive to the bonding surface of the substrates to form an adhesive layer, and then bond the adhesive layers together. Furthermore, to increase the bonding strength when bonding the bonding surfaces of the substrates together, it is preferable to apply a surface activation treatment such as plasma treatment or FAB (Fast Atom Bombardment) treatment to the bonding surface of the substrates.

However, if a surface activation treatment is applied to the adhesive layer, the surface activation treatment may affect the resin contained in the adhesive layer, potentially altering its quality and thus impacting its reliability. Alternatively, while the bonding surface of the substrate may be cleaned to remove particles and other contaminants, the presence of an adhesive layer on the bonding surface limits the cleaning methods available. For these reasons, even when a resin layer is provided on the bonding surface of the substrate, a manufacturing method for substrate laminates that minimizes limitations on the surface activation treatment and cleaning methods for the bonding surface of the substrate is desirable.

One aspect of the present invention has been made in view of the above problems, and aims to provide a method for manufacturing a substrate laminate in which a resin layer is provided on the bonding surface of the substrate, and in which limitations on the method of surface activation treatment and cleaning treatment of the bonding surface of the substrate are suppressed, and a laminate that can be used in this manufacturing method.

The specific means for solving the aforementioned problems are as follows:
Step A to prepare: <1> A first laminate in which a first resin layer, a first substrate, and a first inorganic material layer are laminated in that order, with the first resin layer on one surface and the first inorganic material layer on the other surface; and a second laminate in which a second resin layer, a second substrate, and a second inorganic material layer are laminated in that order, with the second resin layer on one surface and the second inorganic material layer on the other surface.
Step B involves bringing the first resin layer of the first laminate and the second inorganic material layer of the second laminate into contact to laminate the first laminate and the second laminate,
A method for manufacturing a substrate laminate, comprising step C, after step B, of heating the first laminate and the second laminate to 100°C or higher.
<2> The first laminate is provided with electrodes on a part of the surface of the first resin layer and a part of the surface of the first inorganic material layer.
The method for manufacturing a substrate laminate according to <1>, wherein the second laminate is provided with electrodes on a part of the surface of the second resin layer and a part of the surface of the second inorganic material layer.
<3> A method for manufacturing a substrate laminate according to <2>, comprising the step of applying a surface activation treatment to the second inorganic material layer before step B.
<4> A method for manufacturing a substrate laminate according to <1>, comprising the step of providing through holes in the first laminate and the second laminate from the surface on the first inorganic material layer side toward the surface on the second resin layer side after step C, and forming electrodes that penetrate the first laminate and the second laminate in the through holes.
<5> A method for manufacturing a substrate laminate according to any one of <1> to <4>, comprising a step of cleaning the second inorganic material layer before step B.
<6> A method for manufacturing a substrate laminate according to any one of <1> to <5>, comprising the step of providing a surface protective layer on the second inorganic material layer before step B.
<7> The method for manufacturing a substrate laminate according to any one of <1> to <6>, wherein, before bringing the first resin layer and the second inorganic material layer into contact in step B, the composite modulus of the first resin layer at 23°C is 0.1 GPa or more and 20 GPa or less.
<8> The method for manufacturing a substrate laminate according to any one of <1> to <7>, wherein, before the first resin layer and the second inorganic material layer are brought into contact in step B, the curing rate of the first resin layer is 70% or more and 100% or less.
<9> The method for manufacturing a substrate laminate according to any one of <1> to <8>, wherein, before bringing the first resin layer and the second inorganic material layer into contact in step B, the surface roughness (Ra) of the first resin layer is 0.01 nm or more and 1.2 nm or less.
<10> A method for manufacturing a substrate laminate according to any one of <1> to <9>, wherein the surface of the first resin layer has at least one functional group selected from the group consisting of a silanol group, an amino group, an epoxy group, a hydroxyl group, and a functional group having an unsaturated bond.
<11> The first resin layer is
Siloxane bond and
A method for manufacturing a substrate laminate according to any one of <1> to <10>, comprising at least one selected from the group consisting of ester bonds, ether bonds, amide bonds, and imide bonds.
<12> The method for manufacturing a substrate laminate according to any one of <1> to <11>, wherein the second inorganic material layer contains at least one element selected from the group consisting of Si, Ga, Ge, and As.
<13> A first laminate having a first resin layer, a first substrate, and a first inorganic material layer in this order, wherein the first resin layer is disposed on one surface and the first inorganic material layer is disposed on the other surface,
A second laminate comprising a second resin layer, a second substrate, and a second inorganic material layer in this order, wherein the second resin layer is disposed on one surface and the second inorganic material layer is disposed on the other surface,
It has,
A substrate laminate in which the first laminate and the second laminate are laminated together via the first resin layer of the first laminate and the second inorganic material layer of the second laminate.
<14> The first laminate is provided with electrodes on a part of the surface of the first resin layer and a part of the surface of the first inorganic material layer.
The substrate laminate according to <13>, wherein the second laminate is provided with electrodes on a part of the surface of the second resin layer and a part of the surface of the second inorganic material layer.

One aspect of the present invention provides a method for manufacturing a substrate laminate in which a resin layer is provided on the bonding surface of the substrate, and the limitations on the method of surface activation treatment and cleaning treatment of the bonding surface of the substrate are suppressed, as well as a laminate usable in this manufacturing method.

Figures 1a to 1h are schematic diagrams showing Example 1 of the manufacturing method for the substrate laminate according to the present disclosure. Figures 2a to 2i are schematic diagrams showing Example 2 of the manufacturing method for the substrate laminate according to the present disclosure.

In this disclosure, a numerical range represented by "~" means a range that includes the numbers written before and after "~" as the lower and upper limits, respectively.
In numerical ranges described in stages within this disclosure, the upper or lower limit of one numerical range may be replaced with the upper or lower limit of another numerical range described in stages. Furthermore, in numerical ranges described within this disclosure, the upper or lower limit of that range may be replaced with the values shown in the examples.
In this disclosure, "substrate laminate" means a laminate having a structure in which two substrates, namely a first substrate and a second substrate, are joined via a first resin layer and a second inorganic material layer. The substrate laminate may have three or more substrates, and two of the three or more substrates may have a structure in which they are joined via a first resin layer and a second inorganic material layer.
In this disclosure, “substrate” means “at least one of the first substrate and the second substrate,” “resin layer” means “at least one of the first resin layer and the second resin layer,” and “inorganic material layer” means “at least one of the first inorganic material layer and the second inorganic material layer.”

[Method for manufacturing a substrate laminate]
The present disclosure's method for manufacturing a substrate laminate includes: step A, preparing a first laminate in which a first resin layer, a first substrate, and a first inorganic material layer are laminated in that order, with the first resin layer on one surface and the first inorganic material layer on the other surface; and a second laminate in which a second resin layer, a second substrate, and a second inorganic material layer are laminated in that order, with the second resin layer on one surface and the second inorganic material layer on the other surface; step B, bringing the first resin layer of the first laminate into contact with the second inorganic material layer of the second laminate to laminate the first laminate and the second laminate; and step C, after step B, heating the first laminate and the second laminate to 100°C or higher.

In the method for manufacturing a substrate laminate according to this disclosure, at least two laminates are prepared in step A, in which a resin layer, a substrate, and an inorganic material layer are stacked in that order. In step B, the resin layer (first resin layer) of one laminate and the inorganic material layer (second inorganic material layer) of the other laminate are brought into contact and stacked. Then, in step C, the two stacked laminates are heated to 100°C or higher to obtain a substrate laminate having a structure joined via a resin layer (first resin layer) and an inorganic material layer (second inorganic material layer). In this disclosure, the two substrates can be joined via the resin layer and the inorganic material layer after performing a surface activation treatment, cleaning treatment, etc., on the surface of the inorganic material layer. This makes it possible to increase the bonding strength of the bonding surface and remove particles etc. adhering to the surface of the inorganic material layer without performing a surface activation treatment, cleaning treatment, etc., on the surface of the resin layer. Therefore, a method for manufacturing a substrate laminate is provided in which a resin layer is provided on the bonding surface of the substrate, and the limitations on the method of surface activation treatment and cleaning treatment of the bonding surface of the substrate are suppressed.

[Process A]
A method for manufacturing a substrate laminate according to the present disclosure includes step A of preparing a first laminate and a second laminate. The first laminate comprises a first resin layer, a first substrate, and a first inorganic material layer in that order, with the first resin layer on one surface and the first inorganic material layer on the other surface. Similarly, the second laminate comprises a second resin layer, a second substrate, and a second inorganic material layer in that order, with the second resin layer on one surface and the second inorganic material layer on the other surface.

(First substrate and second substrate)
The materials of the first and second substrates are not particularly limited and can be any commonly used materials. The materials of the first and second substrates may be the same or different.
The first and second substrates preferably contain at least one element selected from the group consisting of Si, Al, Ti, Zr, Hf, Fe, Ni, Cu, Ag, Au, Ga, Ge, Sn, Pd, As, Pt, Mg, In, Ta, and Nb. Examples of materials for the first and second substrates include semiconductors: Si, InP, GaN, GaAs, InGaAs, InGaAlAs, SiC; oxides, carbides, nitrides: borosilicate glass (e.g., Pyrex®), quartz glass ( _SiO₂ ), sapphire, _ZrO₂ , _Si₃N₄ , _AlN ; piezoelectrics, dielectrics: _BaTiO₃ , _LiNbO₃ , _SrTiO₃ , diamond; and metals: Al, Ti, Fe, Cu, Ag, Au, Pt, Pd, Ta, Nb, etc.

Other materials for the first and second substrates may include resins such as polydimethylsiloxane (PDMS), epoxy resin, phenolic resin, polyimide, benzocyclobutene resin, and polybenzoxazole.

The first and second substrates may have a multilayer structure. For example, there are structures in which an inorganic layer such as silicon oxide, silicon nitride, or SiCN (silicon carbonitride) is formed on the surface of a silicon substrate, etc.; structures in which an organic layer such as polyimide resin, polybenzoxazole resin, epoxy resin, cyclotene (Dow, Chem), imide crosslinked siloxane resin, epoxy-modified siloxane, porous silica, organic crosslinked siloxane, or organic-inorganic composite low-k such as black diamond (Applied Materials, Inc.) is formed on the surface of a silicon substrate, etc.; and structures in which a composite of inorganic and organic materials is formed on a silicon substrate.

Each material is primarily used for the following purposes:
Si is used in semiconductor memory, LSI stacking, CMOS image sensors, MEMS encapsulation, optical devices, LEDs, etc.
_SiO2 is used in semiconductor memory, LSI stacking, MEMS encapsulation, microfluidics, CMOS image sensors, optical devices, LEDs, etc.
PDMS is a microfluidic;
InGaAlAs, InGaAs, and InP are optical devices;
InGaAlAs, GaAs, and GaN are used in LEDs, etc.

The thickness of the first substrate and the second substrate is preferably 0.5 μm to 1 mm, more preferably 1 μm to 900 μm, and even more preferably 2 μm to 900 μm, independently of each other.

The shapes of the first and second substrates are not particularly limited. For example, if the first and second substrates are silicon substrates, they may be silicon substrates on which an interlayer insulating layer (Low-k film) is formed, and the silicon substrates may have fine grooves (recesses), fine through holes, etc.

In the method for manufacturing the substrate laminate of this disclosure, surface treatment may be performed on at least one of the surfaces of the first substrate that come into contact with the first resin layer and the surfaces of the second substrate that come into contact with the second resin layer, from the viewpoint of bonding strength. For example, by performing the aforementioned surface treatment, at least one functional group selected from the group consisting of hydroxyl groups, epoxy groups, carboxyl groups, amino groups, and mercapto groups may be formed.

Examples of the aforementioned surface treatments include plasma treatment, chemical treatment, and ozone treatment such as ultraviolet (UV) ozone treatment.

Hydroxyl groups can be provided on the surfaces of the first substrate and the second substrate by performing surface treatments such as plasma treatment, chemical treatment, UV ozone treatment, or other ozone treatments on the surfaces of the substrates.
Preferably, the hydroxyl group exists in a state of being bonded to at least one element selected from the group consisting of Si, Al, Ti, Zr, Hf, Fe, Ni, Cu, Ag, Au, Ga, Ge, Sn, Pd, As, Pt, Mg, In, Ta, and Nb, which is contained in the first substrate or the second substrate. Preferably, the surface of the first substrate that is in contact with the first resin layer and the surface of the second substrate that is in contact with the second resin layer have silanol groups containing hydroxyl groups.

Epoxy groups can be provided on the surfaces of the first and second substrates by performing surface treatments such as silane coupling with epoxysilane on the surfaces of the substrates.

Carboxylic groups can be provided on the surfaces of the first and second substrates by performing surface treatments such as silane coupling with carboxysilane.

The amino groups can be provided on the surfaces of the first and second substrates by performing surface treatments such as silane coupling with aminosilane on the surfaces of the first and second substrates, respectively.

Mercapto groups can be provided on the surfaces of the first and second substrates by performing surface treatments such as silane coupling with mercaptosilane on the surfaces of the substrates.

Furthermore, to enhance bonding strength, a primer such as a silane coupling agent may be formed on at least one of the surfaces of the first and second substrates to which the resin material is applied.

(First resin layer and second resin layer)
The first resin layer is a layer disposed on one surface of the first substrate, and the second resin layer is a layer disposed on one surface of the second substrate. For example, the first resin layer and the second resin layer are formed by applying a resin composition containing a resin material to one surface of the first substrate and one surface of the second substrate, respectively, and then curing the formed resin composition layers.

The resin material included in the resin composition is not particularly limited and includes, for example, materials in which bonds or structures are formed by crosslinking, such as polyimide, polyamide, polyamideimide, parylene, polyalylene ether, tetrahydronaphthalene, and octahydroanthracene; materials in which nitrogen ring-containing structures are formed, such as polybenzoxazal and polybenzoxazine; materials in which bonds or structures such as Si-O are formed by crosslinking; and organic materials such as siloxane-modified compounds.
The resin material used to form the first resin layer and the resin material used to form the second resin layer may be the same or different.

Examples of structures containing an Si-O bond (siloxane bond) include those represented by the following formulas (1) to (3).

In a structure having an Si-O bond (siloxane bond), the group bonded to Si may be substituted with an alkylene group, a phenylene group, etc. For example, a structure such as (-O-) _x ( _R1 ) _y Si-( _R2 )-Si( _R1 ) _y (-O-) _x may be present ( _R1 represents a methyl group, etc., and _R2 represents an alkylene group, a phenylene group, etc. x and y are each independent integers of 0 or more, and x + y is 3).

Examples of materials in which Si-O bonds are formed by crosslinking include compounds represented by formulas (4) and (5) shown below. Furthermore, structures represented by formulas (1) and (2) can be produced, for example, by heating and reacting compounds represented by formulas (4) and (5).

For example, if the resin material includes materials such as polyimide, polyamide, and polyamide-imide, in which the bonding or structure is formed by crosslinking, it is preferable to include a compound (A) having a cationic functional group containing at least one primary nitrogen atom and a secondary nitrogen atom, and having a weight-average molecular weight of 90 to 400,000, and a crosslinking agent (B) having three or more -C(=O)OX groups (where X is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms) in its molecule, with one to six of the three or more -C(=O)OX groups being -C(=O)OH groups, and having a weight-average molecular weight of 200 to 2000.

(Compound (A))
Compound (A) is a compound having a cationic functional group containing at least one primary nitrogen atom and a secondary nitrogen atom, and having a weight-average molecular weight of 90 to 400,000. The cationic functional group is not particularly limited as long as it can carry a positive charge and contains at least one primary nitrogen atom and a secondary nitrogen atom.

Furthermore, compound (A) may contain tertiary nitrogen atoms in addition to primary and secondary nitrogen atoms.

In this disclosure, "primary nitrogen atom" refers to a nitrogen atom bonded to only two hydrogen atoms and one non-hydrogen atom (for example, a nitrogen atom contained in a primary amino group ( _-NH₂ group)), or a nitrogen atom (cation) bonded to only three hydrogen atoms and one non-hydrogen atom.
Furthermore, "secondary nitrogen atom" refers to a nitrogen atom bonded to only one hydrogen atom and two non-hydrogen atoms (i.e., a nitrogen atom contained in the functional group represented by formula (a) below), or a nitrogen atom (cation) bonded to only two hydrogen atoms and two non-hydrogen atoms.
Furthermore, "tertiary nitrogen atom" refers to a nitrogen atom bonded to only three atoms other than hydrogen (i.e., a nitrogen atom that is a functional group represented by formula (b) below), or a nitrogen atom (cation) bonded to only one hydrogen atom and three atoms other than hydrogen.

In formulas (a) and (b), * indicates the bonding position with an atom other than a hydrogen atom.
Here, the functional group represented by formula (a) may be a functional group that constitutes part of a secondary amino group (-NHR ^a group; where Ra ^a represents an alkyl group), or it may be a divalent linking group contained in the polymer backbone.
Furthermore, the functional group represented by formula (b) (i.e., a tertiary nitrogen atom) may be a functional group that constitutes part of a tertiary amino group (-NR ^b R ^c group; where R ^b and R ^c each independently represent an alkyl group), or it may be a trivalent linking group included in the polymer backbone.

The weight-average molecular weight of compound (A) is 90 to 400,000. Examples of compound (A) include aliphatic amines, compounds having a siloxane bond (Si-O bond) and an amino group, and amine compounds that do not have an Si-O bond in the molecule and have a ring structure. When compound (A) is an aliphatic amine, the weight-average molecular weight is preferably 10,000 to 200,000. When compound (A) is a compound having a siloxane bond (Si-O bond) and an amino group, the weight-average molecular weight is preferably 130 to 10,000, more preferably 130 to 5,000, and even more preferably 130 to 2,000. When compound (A) is an amine compound that does not have an Si-O bond in the molecule and has a ring structure, the weight-average molecular weight is preferably 90 to 600.

In this disclosure, weight-average molecular weight refers to the weight-average molecular weight in terms of polyethylene glycol, measured by GPC (Gel Permeation Chromatography) for substances other than monomers.
Specifically, the weight-average molecular weight is calculated using polyethylene glycol/polyethylene oxide as a standard, with polyethylene glycol/polyethylene oxide as the standard. The refractive index is detected at a flow rate of 1.0 mL/min using a Shodex DET RI-101 analyzer and two types of analytical columns (TSKgel G6000PWXL-CP and TSKgel G3000PWXL-CP manufactured by Tosoh Corporation).

Furthermore, compound (A) may optionally have anionic functional groups, nonionic functional groups, etc.
The nonionic functional group may be either a hydrogen bond acceptor or a hydrogen bond donor. Examples of the nonionic functional group include a hydroxyl group, a carbonyl group, an ether group (-O-), and the like.
The anionic functional group is not particularly limited as long as it is a functional group capable of carrying a negative charge. Examples of the anionic functional group include carboxylic acid groups, sulfonic acid groups, and sulfate groups.

Examples of compound (A) include aliphatic amines, but more specifically, polyalkyleneimines, which are polymers of alkyleneimines such as ethyleneimine, propyleneimine, butyleneimine, pentyleneimine, hexyleneimine, heptyleneimine, octileneimine, trimethyleneimine, tetramethyleneimine, pentamethyleneimine, hexamethyleneimine, and octamethyleneimine; polyallylamines; and polyacrylamides.

Polyethyleneimine (PEI) can be produced by known methods described in Japanese Patent Publication No. 43-8828, Japanese Patent Publication No. 49-33120, Japanese Patent Application Publication No. 2001-213958, and International Publication No. 2010/137711, etc. Other polyalkyleneimines can also be produced by the same methods as polyethyleneimine.

Compound (A) is also preferably a derivative of the polyalkyleneimine described above (polyalkyleneimine derivative; particularly preferably polyethyleneimine derivative). There are no particular restrictions on the polyalkyleneimine derivative as long as it is a compound that can be produced using the above polyalkyleneimine. Specifically, examples include polyalkyleneimine derivatives obtained by introducing an alkyl group (preferably an alkyl group having 1 to 10 carbon atoms), an aryl group, etc., into polyalkyleneimine, and polyalkyleneimine derivatives obtained by introducing a crosslinking group such as a hydroxyl group into polyalkyleneimine.
These polyalkylene imine derivatives can be produced by methods commonly used with the above-mentioned polyalkylene imines. Specifically, they can be produced, for example, in accordance with the method described in Japanese Patent Application Publication No. 6-016809.

Furthermore, as a polyalkyleneimine derivative, highly branched polyalkyleneimines obtained by reacting polyalkyleneimine with a monomer containing a cationic functional group to improve the degree of branching of the polyalkyleneimine are also preferred.
Methods for obtaining highly branched polyalkyleneimines include, for example, a method in which a polyalkyleneimine having multiple secondary nitrogen atoms in its skeleton is reacted with a monomer containing a cationic functional group, thereby substituting at least one of the multiple secondary nitrogen atoms with the monomer containing a cationic functional group; and a method in which a polyalkyleneimine having multiple primary nitrogen atoms at its terminals is reacted with a monomer containing a cationic functional group, thereby substituting at least one of the multiple primary nitrogen atoms with the monomer containing a cationic functional group.
Cationic functional groups that can be introduced to improve the degree of branching include aminoethyl group, aminopropyl group, diaminopropyl group, aminobutyl group, diaminobutyl group, and triaminobutyl group. However, the aminoethyl group is preferred because it reduces the equivalent amount of cationic functional groups and increases the density of cationic functional groups.

Furthermore, the polyethyleneimine and its derivatives may be commercially available. For example, polyethyleneimine and its derivatives can be appropriately selected and used from those commercially available from companies such as Nippon Shokubai Co., Ltd., BASF, MP-Biomedicals, etc.

Compound (A) includes, in addition to the aliphatic amines mentioned above, compounds having an Si-O bond and an amino group. Examples of compounds having an Si-O bond and an amino group include siloxanediamines, silane coupling agents having an amino group, and siloxane polymers of silane coupling agents having an amino group.
Examples of silane coupling agents containing an amino group include compounds represented by the following formula (A-3).

In formula (A-3), ^R1 represents an optionally substituted C1-C4 alkyl group. ^R2 and ^R3 each independently represent an optionally substituted C1-C12 alkylene group, ether group, or carbonyl group (which may contain carbonyl groups, ether groups, etc. in the skeleton). ^R4 and ^R5 each independently represent an optionally substituted C1-C4 alkylene group or single bond. Ar represents a divalent or trivalent aromatic ring. ^X1 represents hydrogen or an optionally substituted C1-C5 alkyl group. ^X2 represents hydrogen, a cycloalkyl group, a heterocyclic group, an aryl group, or an optionally substituted C1-C5 alkyl group (which may contain carbonyl groups, ether groups, etc. in the skeleton). Multiple ^R1 , ^R2 , ^R3 , ^R4 , ^R5 , and ^X1 may be the same or different.
The substituents on the alkyl and alkylene groups in ^R1 , ^R2 , ^R3 , ^R4 , ^R5 , ^X1 , and ^X2 can be, independently, amino groups, hydroxyl groups, alkoxy groups, cyano groups, carboxylic acid groups, sulfonic acid groups, halogens, and the like.
Examples of divalent or trivalent aromatic rings in Ar include divalent or trivalent benzene rings. Examples of aryl groups in ^X2 include phenyl groups, methylbenzyl groups, vinylbenzyl groups, etc.

Specific examples of silane coupling agents represented by formula (A-3) include, for example, N-(2-aminoethyl)-3-aminopropylmethyldiethoxysilane, N-(2-aminoethyl)-3-aminopropyltriethoxysilane, N-(2-aminoethyl)-3-aminoisobutyldimethylmethoxysilane, N-(2-aminoethyl)-3-aminoisobutylmethyldimethoxysilane, N-(2-aminoethyl)-11-aminoundecyltrimethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, (aminoethylaminoethyl)phenyltriethoxysilane, methylbenzylaminoethylaminopropyltrimethoxysilane, benzylaminoethylaminopropyltriethoxysilane, 3-ureidopropyltriethoxysilane, (aminoethylaminoethyl)phenyltriethoxysilane, Examples include (Tylaminoethyl)phenethyltrimethoxysilane, (aminoethylaminomethyl)phenethyltrimethoxysilane, N-[2-[3-(trimethoxysilyl)propylamino]ethyl]ethylenediamine, 3-aminopropyldiethoxymethylsilane, 3-aminopropyldimethoxymethylsilane, 3-aminopropyldimethylethoxysilane, 3-aminopropyldimethylmethoxysilane, trimethoxy[2-(2-aminoethyl)-3-aminopropyl]silane, diaminomethylmethyldiethoxysilane, methylaminomethylmethyldiethoxysilane, p-aminophenyltrimethoxysilane, N-methylaminopropyltriethoxysilane, N-methylaminopropylmethyldiethoxysilane, (phenylaminomethyl)methyldiethoxysilane, acetamidopropyltrimethoxysilane, and hydrolysates thereof.

Examples of silane coupling agents containing amino groups other than formula (A-3) include N,N-bis[3-(trimethoxysilyl)propyl]ethylenediamine, N,N'-bis[3-(trimethoxysilyl)propyl]ethylenediamine, bis[(3-triethoxysilyl)propyl]amine, piperazinylpropylmethyldimethoxysilane, bis[3-(triethoxysilyl)propyl]urea, bis(methyldiethoxysilylpropyl)amine, 2,2-dimethoxy-1,6-diaza-2-silacyclooctane, 3,5-diamino-N-(4-(methoxydimethylsilyl)phenyl)benzamide, 3,5-diamino-N-(4-(triethoxysilyl)phenyl)benzamide, 5-(ethoxydimethylsilyl)benzene-1,3-diamine, and their hydrolysates.

The aforementioned silane coupling agents having amino groups may be used individually or in combination of two or more. Furthermore, a silane coupling agent having amino groups may be used in combination with a silane coupling agent without amino groups. For example, a silane coupling agent having mercapto groups may be used to improve adhesion to metals.

Furthermore, polymers formed via siloxane bonds (Si-O-Si) from these silane coupling agents (siloxane polymers) may also be used. For example, from the hydrolysis product of 3-aminopropyltrimethoxysilane, polymers having a linear siloxane structure, polymers having a branched siloxane structure, polymers having a cyclic siloxane structure, polymers having a cage-like siloxane structure, etc., can be obtained. The cage-like siloxane structure is represented, for example, by the following formula (A-1).

Examples of siloxanediamines include compounds represented by the following formula (A-2). In formula (A-2), i is an integer from 0 to 4, j is an integer from 1 to 3, and Me is a methyl group.

Furthermore, examples of siloxanediamines include 1,3-bis(3-aminopropyl)tetramethyldisiloxane (in formula (A-2), i=0, j=1) and 1,3-bis(2-aminoethylamino)propyltetramethyldisiloxane (in formula (A-2), i=1, j=1).

Compound (A) includes the aliphatic amines and compounds having an Si-O bond and an amino group as described above, as well as amine compounds that do not have an Si-O bond in the molecule and have a ring structure. Among these, amine compounds with a weight-average molecular weight of 90 to 600 that do not have an Si-O bond in the molecule and have a ring structure are preferred. Examples of amine compounds with a weight-average molecular weight of 90 to 600 that do not have an Si-O bond in the molecule and have a ring structure include alicyclic amines, aromatic ring amines, and heterocyclic amines. The molecule may have multiple ring structures, and these multiple ring structures may be the same or different. As for amine compounds with ring structures, compounds having an aromatic ring are more preferred because it is easier to obtain a thermally stable compound.
Furthermore, as amine compounds having a weight-average molecular weight of 90 to 600 that do not have Si-O bonds in the molecule and have a ring structure, compounds having primary amino groups are preferred because they readily form thermal crosslinked structures such as amides, amide-imides, and imides together with the crosslinking agent (B), thereby increasing heat resistance. Moreover, as the aforementioned amine compounds, diamine compounds having two primary amino groups and triamine compounds having three primary amino groups are preferred because they readily form a large number of thermal crosslinked structures such as amides, amide-imides, and imides together with the crosslinking agent (B), thereby further increasing heat resistance.

Examples of alicyclic amines include cyclohexylamine and dimethylaminocyclohexane.
Examples of aromatic ring amines include diaminodiphenyl ether, xylenediamine (preferably paraxylenediamine), diaminobenzene, diaminotoluene, methylenedianiline, dimethyldiaminobiphenyl, bis(trifluoromethyl)diaminobiphenyl, diaminobenzophenone, diaminobenzanilide, bis(aminophenyl)fluorene, bis(aminophenoxy)benzene, bis(aminophenoxy)biphenyl, dicarboxydiaminodiphenylmethane, diaminoresorcinol, dihydroxybenzidine, diaminobenzidine, 1,3,5-triaminophenoxybenzene, 2,2'-dimethylbenzidine, tris(4-aminophenyl)amine, 2,7-diaminofluorene, 1,9-diaminofluorene, and dibenzylamine.
Examples of heterocyclic amines include heterocyclic rings containing a sulfur atom as a heteroatom (e.g., thiophene rings), or heterocyclic rings containing a nitrogen atom as a heteroatom (e.g., five-membered rings such as pyrrole rings, pyrrolidine rings, pyrazole rings, imidazole rings, and triazole rings; six-membered rings such as isocyanuric rings, pyridine rings, pyridazine rings, pyrimidine rings, pyrazine rings, piperidine rings, piperazine rings, and triazine rings; and condensed rings such as indole rings, indoline rings, quinoline rings, acridine rings, naphthyridine rings, quinazoline rings, purine rings, and quinoxaline rings).
For example, heterocyclic amines having a nitrogen-containing heterocycle include melamine, ammeline, melam, melem, and tris(4-aminophenyl)amine.
Furthermore, examples of amine compounds having both heterocyclic and aromatic rings include N2,N4,N6-tris(4-aminophenyl)-1,3,5-triazine-2,4,6-triamine.

Since compound (A) has a primary or secondary amino group, it can strongly bond the substrates together through electrostatic interactions with functional groups such as hydroxyl groups, epoxy groups, carboxyl groups, amino groups, and mercapto groups that may be present on the surfaces of the first and second substrates, or by forming dense covalent bonds with such functional groups.
Furthermore, since compound (A) has a primary or secondary amino group, it readily dissolves in the polar solvent (D) described later. By using compound (A), which readily dissolves in the polar solvent (D), the affinity with the hydrophilic surface of the substrate, such as a silicon substrate, is increased, making it easier to form a smooth film and allowing the thickness of the first and second resin layers to be reduced.

As for compound (A), an aliphatic amine or a compound having an Si-O bond and an amino group is preferred from the viewpoint of forming a smooth thin film, and a compound having an Si-O bond and an amino group is more preferred from the viewpoint of heat resistance.

When compound (A) contains a compound having a Si-O bond and an amino group, it is preferable from the viewpoint of forming a smooth thin film if the ratio of the total number of primary and secondary nitrogen atoms in compound (A) to the number of silicon atoms (total number of primary and secondary nitrogen atoms / number of silicon atoms) is 0.2 or more and 5 or less.

When compound (A) contains a compound having an Si-O bond and an amino group, it is preferable that, from the viewpoint of adhesion between substrates, the non-crosslinking group, such as a methyl group bonded to Si in the compound having the Si-O bond and amino group satisfies the relationship (non-crosslinking group)/Si < 2 in molar ratio. By satisfying this relationship, the crosslinking density of the formed film (crosslinking between Si-O-Si bonds and amide bonds, imide bonds, etc.) is improved, the substrates have sufficient adhesion to each other, and it is presumed that delamination of the substrates can be suppressed.

As described above, compound (A) has a cationic functional group containing at least one primary nitrogen atom and a secondary nitrogen atom. Here, if compound (A) contains a primary nitrogen atom, it is preferable that the proportion of primary nitrogen atoms to the total nitrogen atoms in compound (A) is 20 mol% or more, more preferably 25 mol% or more, and even more preferably 30 mol% or more. Furthermore, compound (A) may have a cationic functional group that contains a primary nitrogen atom but does not contain nitrogen atoms other than primary nitrogen atoms (e.g., secondary nitrogen atoms, tertiary nitrogen atoms).

Furthermore, if compound (A) contains secondary nitrogen atoms, it is preferable that the proportion of secondary nitrogen atoms to the total nitrogen atoms in compound (A) be 5 mol% or more and 50 mol% or less, and more preferably 10 mol% or more and 45 mol% or less.

Furthermore, compound (A) may contain tertiary nitrogen atoms in addition to primary and secondary nitrogen atoms. If compound (A) contains tertiary nitrogen atoms, it is preferable that the proportion of tertiary nitrogen atoms to the total nitrogen atoms in compound (A) is 20 mol% or more and 50 mol% or less, and more preferably 25 mol% or more and 45 mol% or less.

In this disclosure, the content of the component derived from compound (A) in the first resin layer or the second resin layer is not particularly limited. For example, it can be 1% by mass or more and 82% by mass or less relative to the entire first resin layer or the entire second resin layer, preferably 5% by mass or more and 82% by mass or less, and more preferably 13% by mass or more and 82% by mass or less.

(Crosslinking agent (B))
The crosslinking agent (B) is a compound having three or more -C(=O)OX groups (where X is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms) in its molecule, with one to six of the three or more -C(=O)OX groups (hereinafter also referred to as "COOX") being -C(=O)OH groups (hereinafter also referred to as "COOH"), and having a weight-average molecular weight of 200 to 2000.

The crosslinking agent (B) is a compound having three or more -C(=O)OX groups (where X is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms) in its molecule, preferably a compound having three to six -C(=O)OX groups in its molecule, and more preferably a compound having three or four -C(=O)OX groups in its molecule.

In the crosslinking agent (B), X in the -C(=O)OX group can be a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, with hydrogen atoms, methyl groups, ethyl groups, and propyl groups being preferred. Note that the X in the -C(=O)OX group may be the same or different.

The crosslinking agent (B) is a compound having one to six -C(=O)OH groups in its molecule where X is a hydrogen atom, preferably a compound having one to four -C(=O)OH groups in its molecule, more preferably a compound having two to four -C(=O)OH groups in its molecule, and even more preferably a compound having two or three -C(=O)OH groups in its molecule.

The crosslinking agent (B) is a compound with a weight-average molecular weight of 200 or more and 2000 or less. The weight-average molecular weight of the crosslinking agent (B) is preferably 200 or more and 1000 or less, more preferably 200 or more and 600 or less, and even more preferably 200 or more and 400 or less.

The crosslinking agent (B) preferably has a ring structure within its molecule. Examples of ring structures include alicyclic structures and aromatic ring structures. Furthermore, the crosslinking agent (B) may have multiple ring structures within its molecule, and these multiple ring structures may be the same or different.

Examples of alicyclic structures include alicyclic structures having 3 to 8 carbon atoms, preferably alicyclic structures having 4 to 6 carbon atoms, and the ring structure may be saturated or unsaturated. More specifically, examples of alicyclic structures include saturated alicyclic structures such as cyclopropane rings, cyclobutane rings, cyclopentane rings, cyclohexane rings, cycloheptane rings, and cyclooctane rings; and unsaturated alicyclic structures such as cyclopropene rings, cyclobutene rings, cyclopentene rings, cyclohexene rings, cycloheptene rings, and cyclooctene rings.

The aromatic ring structure is not particularly limited as long as it exhibits aromaticity. Examples include benzene-based aromatic rings such as benzene rings, naphthalene rings, anthracene rings, and perylene rings; aromatic heterocycles such as pyridine rings and thiophene rings; and non-benzene-based aromatic rings such as indene rings and azulene rings.

The ring structure of the crosslinking agent (B) is preferably at least one selected from the group consisting of a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a benzene ring, and a naphthalene ring. At least one of the benzene ring and the naphthalene ring is more preferable from the viewpoint of further improving the heat resistance of the first resin layer and the second resin layer.

As mentioned above, the crosslinking agent (B) may have multiple ring structures within its molecule. If the ring structure is benzene, it may have a biphenyl structure, a benzophenone structure, a diphenyl ether structure, or the like.

The crosslinking agent (B) preferably has fluorine atoms in its molecule, more preferably has one to six fluorine atoms in its molecule, and even more preferably has three to six fluorine atoms in its molecule. For example, the crosslinking agent (B) may have a fluoroalkyl group in its molecule, specifically a trifluoroalkyl group or a hexafluoroisopropyl group.

Furthermore, examples of crosslinking agents (B) include carboxylic acid compounds such as alicyclic carboxylic acids, benzenecarboxylic acids, naphthalenecarboxylic acids, diphthalic acids, and fluorinated aromatic carboxylic acids; and carboxylic acid ester compounds such as alicyclic carboxylic acid esters, benzenecarboxylic acid esters, naphthalenecarboxylic acid esters, diphthalic acid esters, and fluorinated aromatic carboxylic acid esters. Note that carboxylic acid ester compounds are compounds having a carboxyl group (-C(=O)OH group) in their molecule, and in three or more -C(=O)OX groups, at least one X is an alkyl group having 1 to 6 carbon atoms (i.e., having an ester bond). In this disclosure, by using a carboxylic acid ester compound as the crosslinking agent (B), aggregation due to association between compound (A) and the crosslinking agent (B) is suppressed, resulting in fewer aggregates and pits, and making it easier to adjust the film thickness.

The carboxylic acid compound is preferably a tetravalent or less carboxylic acid compound containing four or fewer -C(=O)OH groups, and more preferably a trivalent or tetravalent carboxylic acid compound containing three or four -C(=O)OH groups.

The carboxylic acid ester compound is preferably a compound that contains three or fewer carboxyl groups (-C(=O)OH groups) and three or fewer ester bonds in its molecule, and more preferably a compound that contains two or fewer carboxyl groups and two or fewer ester bonds in its molecule.

Furthermore, in the carboxylic acid ester compound, if X is an alkyl group having 1 to 6 carbon atoms in three or more -C(=O)OX groups, X is preferably a methyl group, ethyl group, propyl group, butyl group, etc., but it is preferable that X be an ethyl group or a propyl group from the viewpoint of further suppressing aggregation due to association between compound (A) and crosslinking agent (B).

Specific examples of the carboxylic acid compounds mentioned above are, but are not limited to, alicyclic carboxylic acids such as 1,2,3,4-cyclobutanetetracarboxylic acid, 1,2,3,4-cyclopentanetetracarboxylic acid, 1,3,5-cyclohexanetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, 1,2,4,5-cyclohexanetetracarboxylic acid, and 1,2,3,4,5,6-cyclohexanehexacarboxylic acid; benzenecarboxylic acids such as 1,2,4-benzenetricarboxylic acid, 1,3,5-benzenetricarboxylic acid, pyromellitic acid, 3,4'-biphthalic acid, p-phenylenebis(trimellitate acid), benzenepentacarboxylic acid, and mellitic acid; 1,4 Naphthalene carboxylic acids such as 5,8-naphthalenetetracarboxylic acid and 2,3,6,7-naphthalenetetracarboxylic acid; 3,3',5,5'-tetracarboxydiphenylmethane, biphenyl-3,3',5,5'-tetracarboxylic acid, biphenyl-3,4',5-tricarboxylic acid, biphenyl-3,3',4,4'-tetracarboxylic acid, benzophenone-3,3',4,4'-tetracarboxylic acid, 4,4'-oxydiphthalic acid, 3,4'-oxydiphthalic acid, 1,3-bis(phthalic acid)tetramethyldisiloxane, 4,4'-(Ethyne-1,2-diyl)diphthalic acid 4,4'-(1,4-phenylenebis(oxy))diphthalic acid, 4,4'-([1,1'-biphenyl]-4,4'-diylbis(oxy))diphthalic acid, 4,4'-((oxybis(4,1-phenylene))bis(oxy))diphthalic acid Examples include diphthalic acids such as (acid); perylene carboxylic acids such as perylene-3,4,9,10-tetracarboxylic acid; anthracene carboxylic acids such as anthracene-2,3,6,7-tetracarboxylic acid; and fluorinated aromatic ring carboxylic acids such as 4,4'-(hexafluoroisopropylidene)diphthalic acid, 9,9-bis(trifluoromethyl)-9H-xanthene-2,3,6,7-tetracarboxylic acid, and 1,4-ditrifluoromethylpyromellitic acid.

Specific examples of the carboxylic acid ester compounds include compounds in which at least one carboxyl group in the above-mentioned specific examples of carboxylic acid compounds is substituted with an ester group. Examples of carboxylic acid ester compounds include half-esterified compounds represented by the following general formulas (B-1) to (B-5).

In general formulas (B-1) to (B-5), R is independently an alkyl group having 1 to 6 carbon atoms, with methyl, ethyl, propyl, and butyl groups being preferred, and ethyl and propyl groups being more preferred.
In general formula (B-2), Y is a single bond, O, C=O, or C( _CF3 ) ₂ .

Half-esterified compounds can be produced, for example, by mixing a carboxylic acid anhydride (the anhydride of the aforementioned carboxylic acid compound) with an alcohol solvent and opening the ring of the carboxylic acid anhydride.

In this disclosure, the content of components derived from the crosslinking agent (B) in the first resin layer and the second resin layer is not particularly limited. For example, the ratio of the number of carbonyl groups (-(C=O)-Y) in the substance derived from the crosslinking agent (B) to the total number of nitrogen atoms in the substance derived from compound (A) ((-(C=O)-Y)/N) is preferably 0.1 to 3.0, more preferably 0.3 to 2.5, and even more preferably 0.4 to 2.2, respectively. Here, in -(C=O)-Y, Y represents an imide-crosslinked or amide-crosslinked nitrogen atom, OH, or ester group. By having (-(C=O)-Y)/N be 0.1 to 3.0, the first resin layer and the second resin layer suitably have crosslinked structures such as amides, amide-imides, and imides, and exhibit superior heat resistance.

(Polar solvent (D))
Step A may involve applying a resin composition containing a resin material to at least one surface of the first substrate and the second substrate. In this case, the resin composition containing the resin material preferably includes a polar solvent (D) along with the aforementioned compound (A), crosslinking agent (B), and other resin materials. Here, the polar solvent (D) refers to a solvent having a relative permittivity of 5 or more at room temperature. Examples of polar solvents (D) include protic inorganic compounds such as water and heavy water; alcohols such as methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutyl alcohol, isopentyl alcohol, cyclohexanol, ethylene glycol, propylene glycol, 2-methoxyethanol, 2-ethoxyethanol, benzyl alcohol, diethylene glycol, triethylene glycol, and glycerin; ethers such as tetrahydrofuran and dimethoxyethane; aldehydes and ketones such as furfural, acetone, ethyl methyl ketone, and cyclohexane; acid derivatives such as acetic anhydride, ethyl acetate, butyl acetate, ethylene carbonate, propylene carbonate, formaldehyde, N-methylformamide, N,N-dimethylformamide, N-methylacetamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, and hexamethylphosphate; nitriles such as acetonitrile and propionitrile; nitro compounds such as nitromethane and nitrobenzene; and sulfur compounds such as dimethyl sulfoxide. The polar solvent (D) preferably contains a protic solvent, more preferably contains water, and even more preferably contains ultrapure water.
The content of the polar solvent (D) in the resin composition is not particularly limited, but is preferably 1.0% by mass or more and 99.99896% by mass or less, and 40% by mass or more and 99.99896% by mass or less, relative to the entire resin composition.
The boiling point of the polar solvent (D) is preferably 150°C or lower, and more preferably 120°C or lower, in order to volatilize the polar solvent (D) by heating when forming the first resin layer and the second resin layer, thereby reducing the amount of residual solvent in the first and second resin layers.

(Additive (C))
The resin composition containing the resin material may also contain an additive (C) in addition to the aforementioned compound (A), crosslinking agent (B), polar solvent (D), etc. Examples of additive (C) include an acid (C-1) having a carboxyl group and a weight-average molecular weight of 46 to 195, and a base (C-2) having a nitrogen atom and a weight-average molecular weight of 17 to 120, which does not have a ring structure. Although the additive (C) volatilizes when heating is performed to form the first resin layer and the second resin layer, the first resin layer and the second resin layer in the substrate laminate of this disclosure may contain the additive (C).

Acid (C-1) is an acid with a carboxyl group and a weight-average molecular weight of 46 to 195. It is presumed that by including acid (C-1) as additive (C), the amino group in compound (A) and the carboxyl group in acid (C-1) form an ionic bond, thereby suppressing aggregation due to association between compound (A) and the crosslinking agent (B). More specifically, it is presumed that aggregation is suppressed because the interaction (e.g., electrostatic interaction) between the ammonium ion derived from the amino group in compound (A) and the carboxylate ion derived from the carboxyl group in acid (C-1) is stronger than the interaction between the ammonium ion derived from the amino group in compound (A) and the carboxylate ion derived from the carboxyl group in the crosslinking agent (B). However, the present invention is not limited in any way by the above presumption.

The acid (C-1) is not particularly limited as long as it has a carboxyl group and a weight-average molecular weight of 46 or more and 195 or less, and examples include monocarboxylic acid compounds, dicarboxylic acid compounds, and oxydicarboxylic acid compounds. More specifically, examples of acid (C-1) include formic acid, acetic acid, malonic acid, oxalic acid, citric acid, benzoic acid, lactic acid, glycolic acid, glyceric acid, butyric acid, methoxyacetic acid, ethoxyacetic acid, phthalic acid, terephthalic acid, picolinic acid, salicylic acid, and 3,4,5-trihydroxybenzoic acid.

In this disclosure, the content of acid (C-1) in the resin composition including the resin material is not particularly limited. For example, the ratio of the number of carboxyl groups in acid (C-1) to the total number of nitrogen atoms in compound (A) (COOH/N) is preferably 0.01 or more and 10 or less, more preferably 0.02 or more and 6 or less, and even more preferably 0.5 or more and 3 or less.

The base (C-2) is a base having a nitrogen atom and a weight-average molecular weight of 17 to 120. It is presumed that by including the base (C-2) as additive (C) in a resin composition containing a resin material, aggregation due to association between compound (A) and the crosslinking agent (B) is suppressed because the carboxyl group in the crosslinking agent (B) and the amino group in the base (C-2) form an ionic bond. More specifically, it is presumed that aggregation is suppressed because the interaction between the carboxylate ion derived from the carboxyl group in the crosslinking agent (B) and the ammonium ion derived from the amino group in the base (C-2) is stronger than the interaction between the ammonium ion derived from the amino group in compound (A) and the carboxylate ion derived from the carboxyl group in the crosslinking agent (B). However, the present invention is not limited in any way by the above presumption.

The base (C-2) is not particularly limited as long as it has a nitrogen atom and does not have a ring structure with a weight-average molecular weight of 17 or more and 120 or less, and examples include monoamine compounds and diamine compounds. More specifically, examples of base (C-2) include ammonia, ethylamine, ethanolamine, diethylamine, triethylamine, ethylenediamine, N-acetylethylenediamine, N-(2-aminoethyl)ethanolamine, and N-(2-aminoethyl)glycine.

In this disclosure, the content of the base (C-2) in the resin composition including the resin material is not particularly limited. For example, the ratio of the number of nitrogen atoms in the base (C-2) to the number of carboxyl groups in the crosslinking agent (B) (N/COOH) is preferably 0.5 or more and 5 or less, and more preferably 0.9 or more and 3 or less.

When the first resin layer and the second resin layer of the substrate laminate of this disclosure are required to have insulating properties, tetraethoxysilane, tetramethoxysilane, bistriethoxysilylethane, bistriethoxysilylmethane, bis(methyldiethoxysilyl)ethane, 1,1,3,3,5,5-hexaethoxy-1,3,5-trisilacyclohexane, 1,3,5,7-tetramethyl-1,3,5,7-tetrahydroxylcyclosiloxane, 1,1,4,4-tetramethyl-1,4-diethoxydisylethylene, and 1,3,5-trimethyl-1,3,5-trimethyl-1,3,5-triethoxy-1,3,5-trisilacyclohexane may be mixed in order to improve insulating properties or mechanical strength. Furthermore, methyltriethoxysilane, dimethyldiethoxysilane, trimethylethoxysilane, etc. may be mixed in order to improve the hydrophobicity of the first and second resin layers, which have insulating properties. These compounds may also be mixed in order to control etching selectivity.

The resin composition containing the resin material may also contain a solvent other than the polar solvent (D), such as n-hexane.

Furthermore, the resin composition containing the resin material may also contain, for example, phthalic acid, benzoic acid, or derivatives thereof, to improve electrical properties.
Furthermore, the resin composition containing the resin material may also contain benzotriazole or a derivative thereof, for example, to suppress the corrosion of copper.

The pH of the resin composition containing the resin material is not particularly limited, but is preferably 2.0 or higher and 12.0 or lower.

Furthermore, when using an acid (C-1) as additive (C), it is preferable to mix the mixture of acid (C-1) and compound (A) with the crosslinking agent (B). That is, it is preferable to pre-mix compound (A) and acid (C-1) before mixing compound (A) and crosslinking agent (B). This effectively suppresses clouding and gelation of the resin composition containing the resin material when compound (A) and crosslinking agent (B) are mixed (gelation can cause delays in the transparency of the resin composition, which is undesirable).

Furthermore, when using a base (C-2) as additive (C), it is preferable to mix the mixture of the base (C-2) and the crosslinking agent (B) with compound (A). That is, it is preferable to pre-mix the crosslinking agent (B) and the base (C-2) before mixing compound (A) and the crosslinking agent (B). This effectively suppresses clouding and gelation of the resin composition containing the resin material when compound (A) and the crosslinking agent (B) are mixed (gelation can cause delays in the transparency of the resin composition, which is undesirable).

Methods for applying a resin material to at least one surface of the first substrate and the second substrate include vapor deposition methods such as vapor deposition polymerization, CVD (chemical vapor deposition), and ALD (atomic layer deposition), as well as coating methods such as dipping, spraying, spin coating, and bar coating. When applying a resin material by coating, it is preferable to apply a resin composition containing the aforementioned resin material. For example, when forming a film with a thickness of micron size, it is preferable to use the bar coating method, and when forming a film with a thickness of nano size (several nanometers to several hundred nanometers), it is preferable to use the spin coating method. The thickness of the resin material can be appropriately adjusted according to the intended thickness of the first resin layer and the second resin layer.

For example, the method of applying the resin material by spin coating is not particularly limited. For instance, a method can be used in which a resin composition containing the resin material is dropped onto the surface of a first substrate while the first substrate is rotated in a spin coater, and then the rotation speed of the first substrate is increased to dry it.
In a method of applying resin material by spin coating, there are no particular restrictions on conditions such as the rotation speed of the substrate, the amount and duration of the resin composition containing the resin material, and the rotation speed of the substrate during drying. These conditions can be adjusted as appropriate while considering the thickness of the resin material to be formed.

For substrates coated with resin material, the substrate may be cleaned to remove any excess resin material. Cleaning methods include wet cleaning with a rinsing solution such as a polar solvent, and plasma cleaning.

In the method for manufacturing a substrate laminate according to the present disclosure, step A may include a step of curing a resin material applied to one surface of the first substrate and one surface of the second substrate to form a first resin layer and a second resin layer. For example, the resin material is cured by heating or the like to form the first resin layer and the second resin layer. In this case, if the resin material contains a thermosetting compound, it is cured by heating the resin material at a temperature above the curing temperature.

It is preferable to heat and cure the resin material applied to one surface of the first substrate and one surface of the second substrate at 100°C to 450°C.
The aforementioned temperature refers to the surface temperature of the resin material applied to the surface.
By heating the resin material, the solvent in the resin composition containing the resin material is removed. In addition, the components in the resin material react to obtain a cured product, and a first resin layer and a second resin layer containing the cured product are formed.
From the viewpoint of suppressing thermal damage to devices such as semiconductor memory, the temperature is preferably 150°C to 450°C, more preferably 180°C to 400°C, even more preferably 180°C to 250°C, and particularly preferably 180°C to 200°C.

Furthermore, there are no particular restrictions on the pressure when the resin material applied to the surface is heated, but an absolute pressure of 17 Pa or less (or less than atmospheric pressure) is preferred.
The absolute pressure is more preferably 1,000 Pa or more and atmospheric pressure or less, even more preferably 5,000 Pa or more and atmospheric pressure or less, and particularly preferably 10,000 Pa or more and atmospheric pressure or less.

The resin material applied to the surface can be heated by a conventional method using a furnace or hot plate. Examples of furnaces that can be used include the SPX-1120 manufactured by Apex Corporation and the VF-1000LP manufactured by Koyo Thermo Systems Co., Ltd.
Furthermore, the heating of the resin material applied to the surface may be carried out in an atmospheric environment or in an inert gas (nitrogen gas, argon gas, helium gas, etc.) atmosphere.

There are no particular restrictions on the heating time of the resin material applied to the surface; for example, it may be 3 hours or less, and preferably 1 hour or less. There are no particular restrictions on the lower limit of the heating time; for example, it may be 5 minutes.

To shorten the curing time of the resin material applied to the surface, the resin material applied to the surface may be irradiated with ultraviolet (UV) light. Preferred UV light includes ultraviolet light with wavelengths of 170 nm to 230 nm, excimer light with a wavelength of 222 nm, and excimer light with a wavelength of 172 nm. Furthermore, it is preferable to perform UV irradiation under an inert gas atmosphere.

Whether a resin material has hardened can be confirmed, for example, by measuring the peak intensity of specific bonds and structures using FT-IR (Fourier Transform Infrared Spectroscopy). Examples of specific bonds and structures include those generated by crosslinking reactions.
For example, if amide bonds, imide bonds, siloxane bonds, tetrahydronaphthalene structures, oxazole ring structures, etc., are formed, it can be determined that the resin material has hardened, and this can be confirmed by measuring the peak intensities derived from these bonds, structures, etc., using FT-IR.
The amide bond can be identified by the presence of vibrational peaks at approximately 1650 ^cm⁻¹ and 1520 ^cm⁻¹ .
The imide bond can be identified by the presence of vibrational peaks at approximately 1770 ^cm⁻¹ and 1720 ^cm⁻¹ .
Siloxane bonds can be identified by the presence of vibrational peaks between 1000 ^cm⁻¹ and 1080 ^cm⁻¹ .
The tetrahydronaphthalene structure can be identified by the presence of vibrational peaks between 1500 ^cm⁻¹ .
The oxazole ring structure can be confirmed by the presence of vibrational peaks at approximately 1625 ^cm⁻¹ and 1460 ^cm⁻¹ .

Preferably, at least one of the first resin layer and the second resin layer, which are formed by curing a resin material, has a siloxane bond and at least one selected from the group consisting of an ester bond, an ether bond, an amide bond, and an imide bond, and more preferably has a siloxane bond and an imide bond.

The first and second resin layers, formed by curing the resin material, preferably contain 10 ppb by mass or less of sodium and potassium, respectively, on an elemental basis. If the sodium or potassium content is 10 ppb by mass or less on an elemental basis, it is possible to suppress the occurrence of problems in the electrical characteristics of the semiconductor device, such as transistor malfunctions.

The amount of silicon on the surface of the first resin layer and the second resin layer is preferably 20 atomic% or less, more preferably 15 atomic% or less, and even more preferably 10 atomic% or less, independently of each other.
The amount of silicon on the surface of the resin layer can be evaluated by measuring the atomic ratio using an X-ray photoelectron spectroscopy (XPS). Specifically, using an XPS instrument such as AXIS-NOVA (manufactured by KRATOS), the atomic ratio can be measured from the peak intensity of the narrow spectrum when the total amount of each element detected in the wide spectrum is set to 100%.

The thickness of the first resin layer and the second resin layer are preferably 0.001 μm to 8.0 μm, more preferably 0.01 μm to 6.0 μm, and even more preferably 0.03 μm to 5.0 μm, respectively. Having a thickness of 0.001 μm or more for the first and second resin layers increases the bonding strength with the second inorganic material layer, other layers, etc. Having a thickness of 8.0 μm or less for the first and second resin layers suppresses variations in the thickness of the resin layers when forming them on a large-area substrate.

When electrodes are provided on a portion of the surface of the first resin layer and a portion of the surface of the second resin layer, the thickness of the first resin layer and the second resin layer is preferably 0.01 μm to 8.0 μm, more preferably 0.03 μm to 6.0 μm, and even more preferably 0.05 μm to 5.0 μm, from the viewpoint of improving bonding strength with the second inorganic material layer, other layers, etc., and suppressing variations in the thickness of the first resin layer and the second resin layer.

When electrodes are not provided on the surface of the first resin layer and the surface of the second resin layer, the thickness of the first resin layer and the second resin layer is preferably 0.001 μm or more and less than 1.0 μm, more preferably 0.01 μm to 0.8 μm, and even more preferably 0.03 μm to 0.6 μm, from the viewpoint of improving bonding strength with the second inorganic material layer, other layers, etc., and suppressing variations in the thickness of the first resin layer and the second resin layer.

The first resin layer preferably has functional groups on its surface that can form chemical bonds, in order to facilitate the temporary fixing of the first resin layer and the second inorganic material layer at low temperatures as described later, and to increase the bonding strength between the first and second laminates in the substrate laminate. It is more preferable that the first resin layer has at least one functional group selected from the group consisting of silanol groups (Si-OH groups), amino groups, epoxy groups, hydroxyl groups, and functional groups having unsaturated bonds, and it is even more preferable that it has silanol groups from the viewpoint of heat resistance. These functional groups may be formed by surface treatment after the formation of the first resin layer, or by silane coupling agent treatment, etc. Alternatively, compounds containing these functional groups may be mixed into the resin composition.
Examples of functional groups containing unsaturated bonds include vinyl groups, allyl groups, acrylic groups, methacrylic groups, and styryl groups.
The second resin layer may have the aforementioned functional groups that can form chemical bonds on the surface of the second resin layer.

Whether or not the surface of a resin layer contains Si-OH groups can be evaluated by surface analysis of the resin layer using time-of-flight secondary ion mass spectrometry (TOF-SIMS). Specifically, using the TOF-SIMS PHI nanoTOFII (ULVAC, PHIE Corporation), the presence or absence of a peak with a mass-to-charge ratio (m/Z) of 45 can be used to evaluate whether or not the surface of the resin layer contains Si-OH groups.

After forming the first or second resin layer, the surface of at least one of the first and second resin layers may be planarized. Methods for planarization include fly-cutting and chemical mechanical polishing (CMP). One planarization method may be used alone, or two or more methods may be used in combination.

After forming the first or second resin layer, the surface of at least one of the first and second resin layers may be cleaned. Cleaning methods include wet cleaning with a rinsing solution and dry cleaning using plasma, etc. Examples of wet cleaning include ultrasonic cleaning using pure water and spin cleaning using solvents such as NMP.

(First inorganic material layer and second inorganic material layer)
The first inorganic material layer is a layer located on the other surface of the first substrate, and the second inorganic material layer is a layer located on the other surface of the second substrate. For example, the first resin layer may be formed on one surface of the first substrate, and then the first inorganic material layer may be formed on the other surface of the first substrate, or conversely, the first inorganic material layer may be formed and then the first resin layer may be formed. The same applies to the second substrate, and the order in which the second resin layer and the second inorganic material layer are formed is not particularly limited.

The materials of the first inorganic material layer and the second inorganic material layer are not particularly limited and may be any inorganic material used when joining inorganic materials together in a semiconductor substrate. Specifically, the first inorganic material layer and the second inorganic material layer may each independently contain at least one element selected from the group consisting of Si, Al, Ti, Zr, Hf, Fe, Ni, Cu, Ag, Au, Ga, Ge, Sn, Pd, As, Pt, Mg, In, Ta, and Nb, and it is preferable that they contain at least one element selected from the group consisting of Si, Ga, Ge, and As. The first inorganic material layer and the second inorganic material layer may also contain oxides, carbides, nitrides, etc., of the aforementioned elements.
The materials of the first inorganic material layer and the second inorganic material layer may be the same or different.

The method for forming an inorganic material layer on the surface of the substrate is not particularly limited, and conventionally known methods for forming inorganic material layers can be used. For example, CVD, sputtering, AGD (aerosolized gas deposition), sol-gel method, anodic oxidation treatment, and thermal decomposition method can be used.

(electrode)
The first laminate may have electrodes on a portion of the surface of the first resin layer and a portion of the surface of the first inorganic material layer, and the second laminate may have electrodes on a portion of the surface of the second resin layer and a portion of the surface of the second inorganic material layer. In step B, it is preferable that the electrodes provided on the first resin layer side are arranged to be in contact with the electrodes provided on the second inorganic material layer.

A through-hole may be provided in the first laminate from the surface on the first resin layer side toward the surface on the first inorganic material layer side, and an electrode penetrating the first laminate may be provided in the through-hole. A through-hole may be provided in the second laminate from the surface on the second resin layer side toward the surface on the second inorganic material layer side, and an electrode penetrating the second laminate may be provided in the through-hole.

The electrode material is not particularly limited and can be any conventionally known electrode material. Specifically, it can be copper, solder, tin, gold, silver, aluminum, indium, cobalt, tungsten, etc.

The method for providing electrodes to the first and second laminates is not particularly limited, and conventionally known methods can be employed.
In the first laminate, electrodes may be formed on the surface to which the resin material is applied before the first resin layer is formed, or electrodes may be formed on the surface to which the first resin layer is formed after the first resin layer has been formed. The same applies to the second laminate.
In the first laminate, electrodes may be formed on the surface on which the first inorganic material layer is formed before the first inorganic material layer is formed, or electrodes may be formed on the surface on which the first inorganic material layer is formed after the first inorganic material layer has been formed. The same applies to the second laminate.

The electrodes may be formed convexly on the surface of the first substrate or the second substrate, may be formed in a manner that penetrates the first substrate or the second substrate, or may be formed in a manner that is embedded in the first substrate or the second substrate.

If electrodes are formed before the resin layer or inorganic material layer is formed, the electrodes are provided on a portion of the surface of the resin layer or inorganic material layer by removing the resin layer or inorganic material layer on the electrodes. Methods for removing the resin layer or inorganic material layer from the current-carrying layer include fly-cutting, chemical mechanical polishing (CMP), and plasma dry etching. One removal method may be used alone, or two or more methods may be used in combination. For example, in the fly-cutting method, a surface planer (DFS8910 (manufactured by DISCO Corporation)) can be used. When using CMP, the slurry may be, for example, a slurry containing silica or alumina, commonly used for polishing resins, or a slurry containing hydrogen peroxide and silica, commonly used for polishing metals. When using plasma dry etching, fluorocarbon plasma, oxygen plasma, etc., may be used.

If the resin or inorganic material layer on the electrode surface is removed and the electrode is exposed, the oxide on the electrode surface may be reduced as needed. Methods for reduction include heating the substrate in an acidic atmosphere such as formic acid at 100°C to 300°C, or heating the substrate in a hydrogen atmosphere. These treatments may be performed simultaneously with step C, which will be described later.

When electrodes are formed after the resin layer or inorganic material layer has been formed, for example, holes for electrode formation may be formed in the surface of the substrate where the resin layer or inorganic material layer has been formed using a known method, and electrodes may be formed in the formed holes. Methods for forming the holes include dry etching using gas and laser ablation.

Methods for forming electrodes include electroplating, electroless plating, sputtering, and inkjet printing.

If the resin material is photosensitive, holes may be formed in the resin material applied to at least one of the first substrate and the second substrate for forming electrodes by photolithography. After curing the resin material to form at least one of the first resin layer and the second resin layer, electrodes may be formed in the formed holes.

The first and second laminates may be laminates separated into individual pieces by dicing, if necessary. For example, a dicer (DAD6340 (manufactured by DISCO Corporation)) can be used for dicing.

[Process B]
The method for manufacturing a substrate laminate according to the present disclosure includes step B, which involves contacting the first resin layer of the first laminate with the second inorganic material layer of the second laminate to laminate the first laminate and the second laminate.

Step B is a step in which the first resin layer and the second inorganic material layer are brought into contact before the first laminate and the second laminate are joined via the first resin layer and the second inorganic material layer in step C, which will be described later. The first laminate and the second laminate are brought into contact so that they will be in a desired positional relationship when the first laminate and the second laminate are joined together.

For example, if the electrodes described above are provided on the first laminate and the second laminate, respectively, it is preferable to bring the first laminate and the second laminate into contact such that the electrode provided on the first resin layer contacts the electrode provided on the second inorganic material layer.

Before bringing the first resin layer and the second inorganic material layer into contact in step B, it is preferable that the curing rate of the first resin layer be between 70% and 100%. This ensures that the first laminate and the second laminate are firmly bonded in step C described later, and that misalignment of the bonded parts (misalignment) is less likely to occur.

The curing rate of the first resin layer is more preferably 80% or more, even more preferably 85% or more, particularly preferably 90% or more, and even more preferably 93% or more. Furthermore, the curing rate of the first resin layer may be 100%, 99% or less, 95% or less, or 90% or less.
Furthermore, the preferred range for the curing rate of the second resin layer is the same as the preferred range for the curing rate of the first resin layer. The curing rate of the second resin layer may be the curing rate before contact with other layers (for example, other inorganic material layers).

The curing rate of a resin layer (at least one of the first resin layer and the second resin layer) containing at least one selected from the group consisting of amide bonds, imide bonds, siloxane bonds, tetrahydronaphthalene structures, oxazole ring structures, ester bonds, and ether bonds is more preferably 80% or higher, even more preferably 85% or higher, particularly preferably 90% or higher, and even more preferably 93% or higher. The curing rate of a resin layer (at least one of the first resin layer and the second resin layer) containing a siloxane bond and at least one selected from the group consisting of ester bonds, ether bonds, amide bonds, and imide bonds is more preferably 80% or higher, even more preferably 85% or higher, particularly preferably 90% or higher, and even more preferably 93% or higher.

The curing rate of the first resin layer, which is formed by curing the resin material, may be determined by measuring the peak intensity of specific bonds and structures (the sum of the peak intensities if there are multiple peaks, such as imide and amide) using FT-IR (Fourier transform infrared spectroscopy) in the resin material before it is applied to the first substrate, the first resin layer before contact between the first resin layer and the second inorganic material layer in step B, and the first resin layer after step C, and determining the rate of increase or decrease in peak intensity. In cases where there are band-shaped peaks that are difficult to separate, such as siloxane bonds, the maximum peak intensity may be used.

Specifically, if a specific bond and structure are generated by the curing reaction, the rate of increase in peak intensity may be calculated using the following formula, and the calculated value may be taken as the curing rate of the first resin layer.
Increase rate of peak intensity (curing rate of the first resin layer) = [(Peak intensity of specific bonds and structure of the first resin layer before contact with the second inorganic material layer in step B) / (Peak intensity of specific bonds and structure of the first resin layer after heating at 300°C for 1 hour in step C)] × 100
Background signal rejection can be performed using standard methods. Furthermore, FT-IR measurements can be performed using either the transmission or reflection method as needed.

In the aforementioned rate of increase in peak intensity, if there are multiple bonds and structures that cause an increase in peak intensity, the peak intensity may be interpreted as the sum of the multiple peak intensities.

Before contacting the first resin layer and the second inorganic material layer in step B, the composite modulus of the first resin layer at 23°C is preferably 0.1 GPa or more and 20 GPa or less, and more preferably 0.1 GPa or more and 10 GPa or less. This tends to suppress the generation of voids, as the voids formed when the first resin layer and the second inorganic material layer are contacted in step B are absorbed by the first resin layer in step C. Furthermore, this makes it easier to perform the temporary fixing of the first resin layer and the second inorganic material layer at a low temperature, as described later.

The composite modulus of the first resin layer at 23°C is preferably 8 GPa or less, and more preferably 6 GPa or less, from the viewpoint of effectively suppressing the generation of voids. Furthermore, the composite modulus of the first resin layer at 23°C is preferably 0.1 GPa or more, and more preferably 1 GPa or more, from the viewpoint of effectively suppressing alignment misalignment.
Furthermore, the preferred range for the composite modulus of the second resin layer at 23°C is the same as the preferred range for the composite modulus of the first resin layer at 23°C. The composite modulus of the second resin layer at 23°C may be the composite modulus at 23°C before contact with other layers (e.g., other inorganic material layers).

The composite modulus of the resin layer at 23°C can be measured by the method described below.
A resin composition containing resin material is prepared, spin-coated onto a silicon substrate, and then heated at 400°C for 10 minutes to prepare a measurement sample. For the prepared measurement sample, the unloading-displacement curve at 23°C is measured using a nanoindenter (product name TI-950 Tribo Indenter, manufactured by Hysitron, Berkovich type indenter) at a test depth of 20 nm. The composite modulus of elasticity at 23°C is calculated from the maximum load and maximum displacement according to the calculation method described in the reference (Handbook of Micro/nano Tribology (second Edition), edited by Bharat Bhushan, CRC Press).
Here, the composite modulus is defined by the following equation (1). In equation (1), E _r represents the composite modulus, E _i represents the Young's modulus of the indenter, which is 1140 GPa, ν _i represents the Poisson's ratio of the indenter, which is 0.07, and E _s and ν _s represent the Young's modulus and Poisson's ratio of the sample, respectively.

Before bringing the first resin layer and the second inorganic material layer into contact in step B, the surface roughness (Ra) of the first resin layer is preferably 0.01 nm or more and 1.2 nm or less, and more preferably 0.1 nm or more and 1.0 nm or less. This makes it easier to perform the temporary fixing of the first resin layer and the second inorganic material layer, as described later, at a low temperature.
Furthermore, the preferred range for the surface roughness (Ra) of the second resin layer is the same as the preferred range for the surface roughness (Ra) of the first resin layer. The surface roughness (Ra) of the second resin layer may be the surface roughness (Ra) before contact with other layers (for example, other inorganic material layers).
The surface roughness of the resin layer can be evaluated by morphological observation using a scanning probe microscope (SPM). Specifically, using an SPA400 SPM (manufactured by Hitachi High-Technologies), the surface roughness can be determined by measuring a 3 μm x 3 μm square area in dynamic force microscope mode.

The method for manufacturing a substrate laminate according to this disclosure may include the following steps before step B described above. The following steps are preferably performed after step A and before step B.

The method for manufacturing a substrate laminate according to this disclosure may include a step of applying a surface activation treatment to the second inorganic material layer before step B. By applying the surface activation treatment, the bonding strength between the first resin layer and the second inorganic material layer can be increased. In particular, when electrodes are provided on the bonding surfaces of the first laminate and the second laminate and the electrodes are bonded together, it is preferable to apply the surface activation treatment from the viewpoint of promoting the diffusion of metals such as copper contained in the electrodes to increase the bonding strength between the electrodes, and from the viewpoint of reducing the heating temperature during metal diffusion.
Furthermore, the first inorganic material layer on the first substrate may also be subjected to surface activation treatment. In particular, when the first inorganic material layer is bonded to another layer (for example, another resin layer), the first inorganic material layer may also be subjected to surface activation treatment before bonding.

Specific examples of surface activation treatments include plasma treatment and FAB (Fast Atom Bombardment) treatment.

The method for manufacturing a substrate laminate according to this disclosure may include a step of cleaning the second inorganic material layer before step B, in order to remove particles and the like. Preferably, the aforementioned cleaning step is performed after the surface treatment step and before step B.
Furthermore, the first inorganic material layer on the first substrate may be cleaned, and in particular, when the first inorganic material layer is to be bonded to another layer (for example, another resin layer), the first inorganic material layer may be cleaned before bonding.

The cleaning method is not particularly limited and may include wet cleaning using solvents such as alkaline cleaning solutions, acidic cleaning solutions, hydrofluoric acid-containing cleaning solutions, and permanganate-containing solutions (desmear solutions); wet cleaning using pure water; and dry cleaning using UV ozone, plasma, etc.

The method for manufacturing a substrate laminate according to this disclosure may include a step of providing a surface protection layer on the second inorganic material layer before step B, in order to prevent foreign matter from adhering to the inorganic material layer (for example, to prevent foreign matter from adhering during dicing). The step of providing the surface protection layer is preferably performed before the aforementioned cleaning step and before step B.

The surface protective layer is not particularly limited as long as it can protect the second inorganic material layer, and examples include water-soluble resins and photoresists that can be washed with organic solvents such as NMP (N-methyl-2-pyrrolidone). As the water-soluble resin, Disco's Hogomax may be used.

The second laminate, which has a surface protective layer, may be diced as needed, and the surface protective layer may be peeled off after dicing. In this case, it is preferable to peel off the surface protective layer after dicing, and then perform the cleaning step and step B as described above after peeling off the surface protective layer.

The method for manufacturing a substrate laminate according to this disclosure may include a step of temporarily fixing the first laminate and the second laminate after step B and before step C. The temporary fixing of the first laminate and the second laminate is preferably carried out at a low temperature of room temperature or higher and 100°C or lower, more preferably at a low temperature of room temperature or higher and 50°C or lower, and even more preferably at room temperature.

When the first substrate and the second substrate are silicon substrates, the surface energy of the bonding interface between the two laminates in a state where the first and second laminates are temporarily fixed is preferably 0.05 J/m² or more, more preferably 0.1 J/ ^m² or more, and even more preferably 0.15 J/ ^m² or ^more , from the viewpoint of ease of handling in process C, suppression of alignment misalignment (bonding position misalignment), and suppression of foreign matter contamination.
The surface energy (bonding strength) of the aforementioned bonding interface can be determined by a blade insertion test according to the method described in Non-Patent Literature MPMaszara, G.Goetz, A.Cavigila, and JBMckitterick, Journal of Applied Physics, 64 (1988) 4943-4950. A blade with a thickness of 0.1 mm to 0.3 mm is inserted into the bonding interface of a temporarily fixed laminate, and the distance from the blade tip to the delamination of the laminate is measured using an infrared light source and an infrared camera. Then, the surface energy can be calculated based on the following formula.
γ=3× ¹⁰⁹ × _tb2 ^{× E2} × ^t6 /(32× ^L4 ×E× ^t3 )
Here, γ represents the surface energy (J/ ^m² ), _tb represents the blade thickness (m), E represents the Young's modulus (GPa) of the silicon substrate contained in the first and second substrates, t represents the thickness of the first and second substrates (m), and L represents the delamination distance from the blade tip (m).

[Process C]
The method for manufacturing a substrate laminate according to the present disclosure includes, after step B, step C, in which the first laminate and the second laminate are heated to 100°C or higher. This results in a substrate laminate in which the first laminate and the second laminate are bonded together via a first resin layer and a second inorganic material layer.

There are no particular restrictions on the pressure used when joining the first laminate and the second laminate, but an absolute pressure of ^10⁻⁴ Pa or less (or less than atmospheric pressure) is preferred.
The absolute pressure is more preferably ^10⁻³ Pa or more and atmospheric pressure or less, even more preferably 100 Pa or more and atmospheric pressure or less, and particularly preferably 1000 Pa or more and atmospheric pressure or less.
When joining the first laminate and the second laminate, the process may be carried out in an atmospheric environment or in an inert gas atmosphere (such as nitrogen gas, argon gas, or helium gas).

In step C, it is preferable to heat the first laminate and the second laminate at 100°C to 450°C while the first resin layer and the second inorganic material layer are in contact.
The aforementioned temperature refers to the temperature of the surface on which the first resin layer is formed on the first substrate.
The temperature is preferably 100°C to 400°C, more preferably 130°C to 350°C, even more preferably 150°C to 300°C, even more preferably 150°C to 250°C, and particularly preferably 150°C to 200°C.

In step B, when the electrodes are arranged such that the electrode provided on the first resin layer side is in contact with the electrode provided on the second inorganic material layer, the aforementioned temperature is preferably 130°C or higher, more preferably 150°C or higher, and even more preferably 200°C or higher. This causes the components (e.g., copper) contained in the electrode provided on the first resin layer side and the electrode provided on the second inorganic material layer to diffuse, and the bonding strength between the electrodes tends to increase.

Heating in step C can be carried out by a conventional method using a furnace or hot plate.
Furthermore, the heating in step C may be carried out in an atmospheric environment or in an inert gas (nitrogen gas, argon gas, helium gas, etc.) atmosphere.
There are no particular restrictions on the heating time in step C; for example, it may be 3 hours or less, and preferably 1 hour or less. There are no particular restrictions on the lower limit of the heating time; for example, it may be 5 minutes.

In step C, to increase the bonding strength between the first laminate and the second laminate, the first laminate and the second laminate may be pressurized while the first resin layer and the second inorganic material layer are in contact. Pressurization may be performed simultaneously with heating.
There are no particular restrictions on the pressure used when pressurizing the first and second laminates, but it is preferably 0.1 MPa to 10 MPa, and more preferably 0.1 MPa to 5 MPa. As a pressurizing device, for example, a TEST MINI PRESS manufactured by Toyo Seiki Seisakusho Co., Ltd. may be used.

The manufacturing method of the substrate laminate according to this disclosure may include, after step C, a step of providing through holes in the first laminate and the second laminate from the surface on the first inorganic material layer side toward the surface on the second resin layer side, and forming electrodes that penetrate the first laminate and the second laminate in the through holes. It is preferable that if electrodes are not formed in the substrate laminate obtained in step C, this step of forming electrodes is performed so that electrodes that penetrate the first laminate and the second laminate are formed in the through holes.

For example, through-holes penetrating the first and second laminates may be formed by known methods, and electrodes may be formed in the formed holes. Methods for forming the holes include dry etching using gas, laser ablation, and the like.

Methods for forming electrodes that penetrate the first and second laminates include electroplating, electroless plating, sputtering, and inkjet methods.

The material of the electrode penetrating the first and second laminates is not particularly limited, and examples include conventionally known electrode materials. Specifically, examples include copper, solder, tin, gold, silver, aluminum, indium, cobalt, tungsten, etc.

In the method for manufacturing a substrate laminate according to this disclosure, at least one of the first substrate and the second substrate may have another substrate, another laminate, etc., laminated on the surface facing the first inorganic material layer and the surface facing the second resin layer. The preferred material of the other substrate is the same as the preferred material of the first substrate and the second substrate. The preferred embodiment of the other laminate is the same as the preferred embodiment of the first laminate and the second laminate.

In the method for manufacturing a substrate laminate according to this disclosure, thinning (back grinding or back surface grinding) may be performed on the surface of the substrate laminate after step C, if necessary.

(Example of a laminated structure of a substrate)
The following shows examples of laminated structures for substrates in various applications. Note that the term "bonding layer" refers to a layer consisting of an inorganic material layer and a resin layer in a bonded state.
For MEMS packaging; Si/bonding layer/Si, _SiO2 /bonding layer/Si, _SiO2 /bonding layer/ _SiO2 , Cu/bonding layer/Cu,
For microchannel; PDMS/bonding layer/PDMS, PDMS/bonding layer/SiO ₂ ,
For CMOS image sensors; _SiO2 /bonding layer/ _SiO2 , Si/bonding layer/Si, _SiO2 /bonding layer/Si,
For through-silicon vias (TSVs); _SiO₂ (with Cu electrode) / junction layer / _SiO₂ (with Cu electrode), Si (with Cu electrode) / junction layer / Si (with Cu electrode),
For optical devices; (InGaAlAs, InGaAs, InP, GaAs) / bonding layer / Si,
For LEDs; (InGaAlAs, GaAs, GaN)/bonding layer/Si, (InGaAlAs, GaAs, GaN)/bonding layer/ _SiO2 , (InGaAlAs, GaAs, GaN)/bonding layer/(Au, Ag, Al), (InGaAlAs, GaAs, GaN)/bonding layer/Sapphire.

The following describes an example of a method for manufacturing a substrate laminate using Figures 1a to 1h and Figures 2a to 2i. Note that this disclosure is not limited to the configurations shown in the drawings. Furthermore, the sizes of the components in Figures 1a to 1h and Figures 2a to 2i are conceptual, and the relative relationships between the components are not limited thereto. Also, in each drawing, components having substantially the same function are given the same reference numerals, and redundant explanations may be omitted.

<Example 1 of a manufacturing method for a substrate laminate>
The following describes Example 1 of a method for manufacturing a substrate laminate using Figures 1a to 1h. As shown in Figure 1a, a wafer 3 with a flattened surface and through-electrodes 4 is prepared. An inorganic material layer 5, such as an oxide film, is formed on the surface of the wafer 3. The wafer 3 with electrodes 4 is fixed to the carrier 1 via a temporary fixing material 2.

Next, as shown in Figure 1b, the inorganic material layer 5 on the surface of the wafer 3 is subjected to the surface activation treatment described above.

Furthermore, a laminate is prepared comprising an inorganic material layer 15, a wafer 13, and a resin layer 16 in this order, and further comprising an electrode 14 penetrating the wafer 13. As shown in Figure 1c, a surface protective material 6 is arranged on the inorganic material layer 15 side of the laminate.

As shown in Figure 1d, after dicing the laminate, the surface protective material 6 is peeled off to obtain individual laminates. Each individual laminate comprises an individual inorganic material layer 15A, a wafer 13A, and a resin layer 16A in that order. Furthermore, each individual laminate is provided with an electrode 14A that penetrates the individual laminate. From the viewpoint of removing foreign matter, the surface of the individual laminate may be washed with pure water, a solvent, etc., after peeling off the surface protective material 6. At this time, multiple individual laminates may be washed together while still stacked on the frame.

Next, as shown in Figure 1e, the inorganic material layer 5 on the surface of the wafer 3 and the resin layer 16A of the individualized laminate are brought into contact and temporarily fixed. At this time, multiple individualized laminates may be temporarily fixed along the width and length directions.

As shown in Figure 1f, the inorganic material layer 15A of the individualized laminate temporarily fixed to the wafer 3 is subjected to the surface activation treatment described above. After surface activation, the surface of the inorganic material layer 15A may be washed with pure water, a solvent, or the like.

Following the procedure shown in Figures 1c and 1d, a fragmented laminate is obtained comprising fragmented inorganic material layers 15B, a wafer 13B, and a resin layer 16B in that order. The fragmented laminate is provided with an electrode 14B that penetrates the fragmented laminate. As shown in Figure 1g, the inorganic material layer 15A and the resin layer 16B of the fragmented laminate, which are temporarily fixed to the wafer 3, are brought into contact and temporarily fixed. At this time, multiple fragmented laminates may be temporarily fixed along the width and length directions.

By repeating the processes shown in Figures 1f and 1g, the individualized laminates are stacked in a state where they are temporarily fixed in the height direction. After the stacking of the individualized laminates is complete, the stack of individualized laminates is heated to 100°C or higher. This allows the wafer 3 and the individualized wafer 13B to be joined via the inorganic material layer 5 and the resin layer 16A, and the individualized laminates stacked in the height direction to be joined via each individualized inorganic material layer and each resin layer. From the viewpoint of increasing the bonding strength between each electrode, it is preferable to heat the stack of individualized laminates to 130°C or higher. This tends to increase the bonding strength between electrodes as the components contained in each electrode (e.g., copper) diffuse.
As a result of the above, a substrate laminate 100 is obtained as shown in Figure 1h.

<Example 2 of a manufacturing method for a substrate laminate>
Below, Example 2 of the method for manufacturing a substrate stack will be described using Figures 2a to 2i. Example 2 of the method for manufacturing a substrate stack differs from Example 1 of the method for manufacturing a substrate stack described above in that it uses a wafer without electrodes, ultimately creates through holes in the substrate stack that does not have electrodes, and then provides electrodes in these through holes.

As shown in Figure 2a, a wafer 23 with a flattened surface is prepared. An inorganic material layer 25, such as an oxide film, is formed on the surface of the wafer 23. The wafer 23 is fixed to the carrier 1 via a temporary fixing material 2.

Next, as shown in Figure 2b, the inorganic material layer 25 on the surface of the wafer 23 is subjected to the surface activation treatment described above.

Furthermore, a laminate is prepared comprising an inorganic material layer 35, a wafer 33, and a resin layer 36 in this order. As shown in Figure 2c, a surface protective material 6 is placed on the inorganic material layer 35 side of the laminate.

As shown in Figure 2d, after dicing the laminate, the surface protective material 6 is peeled off to obtain individual laminates. Each individual laminate comprises an individual inorganic material layer 35A, a wafer 33A, and a resin layer 36A in that order. From the viewpoint of removing foreign matter, the surface of the individual laminates may be washed with pure water, a solvent, etc., after peeling off the surface protective material 6. At this time, multiple individual laminates may be washed together while still stacked on the frame.

Next, as shown in Figure 2e, the inorganic material layer 25 on the surface of the wafer 23 and the resin layer 36A of the individualized laminate are brought into contact and temporarily fixed. At this time, multiple individualized laminates may be temporarily fixed along the width and length directions.

As shown in Figure 2f, the inorganic material layer 35A of the individualized laminate temporarily fixed to the wafer 23 is subjected to the surface activation treatment described above. After surface activation, the surface of the inorganic material layer 35A may be washed with pure water, a solvent, or the like.

Following the procedure shown in Figures 2c and 2d, a fragmented laminate is obtained comprising fragmented inorganic material layers 35B, a wafer 33B, and a resin layer 36B in that order. As shown in Figure 2g, the inorganic material layer 35A and the resin layer 36B of the fragmented laminate, which are temporarily fixed to the wafer 23, are brought into contact and temporarily fixed. At this time, multiple fragmented laminates may be temporarily fixed along the width and length directions.

By repeating the process shown in Figures 2f and 2g, the individualized laminates are stacked in a state where they are temporarily fixed in the height direction. After the stacking of the individualized laminates is complete, the stack of individualized laminates is heated to 100°C or higher. This allows the wafer 23 and the individualized wafer 33B to be joined via the inorganic material layer 25 and the resin layer 36A, and the individualized laminates stacked in the height direction to be joined via each individualized inorganic material layer and each resin layer. As a result, a substrate laminate 200 is obtained as shown in Figure 2h.

Furthermore, through holes are provided that penetrate the individual laminates stacked on the substrate laminate 200 along the height direction. Methods for forming the through holes include dry etching using gas and laser ablation. Next, electrodes 34 are formed that penetrate the individual laminates stacked on the through holes.
As a result, a substrate laminate 300 is obtained, which has electrodes 34 penetrating the individualized laminate, as shown in Figure 2i.

[Laminated substrate]
The substrate laminate of the present disclosure comprises a first resin layer, a first substrate, and a first inorganic material layer in this order, wherein the first resin layer is disposed on one surface and the first inorganic material layer is disposed on the other surface of the first laminate,
A second laminate comprising a second resin layer, a second substrate, and a second inorganic material layer in this order, wherein the second resin layer is disposed on one surface and the second inorganic material layer is disposed on the other surface,
It has,
The first laminate and the second laminate are laminated together via the first resin layer of the first laminate and the second inorganic material layer of the second laminate.
The first and second laminates in the substrate laminate of this disclosure may be laminates that are three-dimensionally mounted on a substrate such as a wafer, and examples include the first and second laminates used in the manufacturing method of the substrate laminate of this disclosure described above. Preferred forms of the first and second laminates in the substrate laminate are the same as preferred forms of the first and second laminates in the manufacturing method of the substrate laminate of this disclosure described above.
For example, specific examples of the first and second laminates in a substrate laminate include the laminate shown in Figure 1c or Figure 2c, and the segmented laminate shown in Figures 1d and 2d.
Preferably, the first or second laminate in the substrate laminate of this disclosure is a laminate for a three-dimensional semiconductor device.

In the substrate laminate of the present disclosure, the first laminate is provided with electrodes on a part of the surface of the first resin layer and a part of the surface of the first inorganic material layer.
Preferably, the second laminate is provided with electrodes on a portion of the surface of the second resin layer and a portion of the surface of the second inorganic material layer.
The preferred form of the electrode is the same as the preferred form of the electrode in the manufacturing method of the substrate laminate described above.

<Modified Method of Manufacturing Substrate Laminates>
A modified version of the method for manufacturing a substrate laminate according to the present disclosure differs from the method for manufacturing a substrate laminate according to the present disclosure described above in that, instead of the first laminate, a laminate (third laminate) is used in which a first resin layer, a first substrate, and a third resin layer are stacked in that order, and instead of the second laminate, a laminate (third laminate) is used in which a second resin layer, a first substrate, and a fourth resin layer are stacked in that order. In other words, in the laminate (third laminate), the first inorganic material layer in the first laminate is replaced by the third resin layer, and in the laminate (fourth laminate), the second inorganic material layer in the second laminate is replaced by the fourth resin layer. The substrate laminate is then obtained in the modified version by joining the first resin layer and the fourth resin layer in step C.

In the modified example, it is preferable that the first resin layer and the fourth resin layer have different resin compositions, and that the resin material used to form the first resin layer and the resin material used to form the fourth resin layer have different resin compositions. This tends to effectively suppress warping of the substrate laminate, even when the thickness of the third and fourth laminates is small.

The resin material used to form the first resin layer is preferably a resin material capable of forming a resin layer with a composite elastic modulus of 0.1 GPa or more and 10 GPa or less at 23°C. In other words, the composite elastic modulus of the first resin layer at 23°C is preferably 0.1 GPa or more and 10 GPa or less.
The resin material used to form the first resin layer, and the preferred conditions for the first resin layer, are the same as those described above in the method for manufacturing the substrate laminate of this disclosure.

The resin material used to form the fourth resin layer is not particularly limited as long as its composition differs from that of the resin material used to form the first resin layer. Examples include materials in which bonds or structures are formed by crosslinking, such as polyimide, polyamide, polyamideimide, parylene, polyalylene ether, tetrahydronaphthalene, and octahydroanthracene; materials in which nitrogen ring-containing structures are formed, such as polybenzoxazal and polybenzoxazine; materials in which bonds or structures such as Si-O are formed by crosslinking; organic materials such as siloxane-modified compounds; benzocyclobutene; and epoxy compounds.

The resin material used to form the fourth resin layer is preferably a material in which polyimide bonds are formed by crosslinking, benzocyclobutene, an epoxy compound, a siloxane-modified compound, etc. The material in which polyimide bonds are formed by crosslinking is preferably a siloxane compound in which polyimide bonds are formed by crosslinking, and the siloxane-modified compound is preferably an epoxy-modified siloxane.

—Explanation of symbols—
1: Carrier, 2: Temporary fixing material, 3: Wafer, 4: Electrode, 5: Inorganic material layer, 6: Surface protective material, 13: Wafer, 13A: Wafer, 13B: Wafer, 14: Electrode, 14A: Electrode, 14B: Electrode, 15: Inorganic material layer, 15A: Inorganic material layer, 15B: Inorganic material layer, 16: Resin layer, 16A: Resin layer, 16B: Resin layer, 23: Wafer, 25: Inorganic material layer, 33: Wafer, 33A: Wafer, 33B: Wafer, 34: Electrode, 35: Inorganic material layer, 35A: Inorganic material layer, 35B: Inorganic material layer, 36: Resin layer, 36A: Resin layer, 36B: Resin layer, 100: Substrate laminate, 200: Substrate laminate, 300: Substrate laminate

Furthermore, the disclosure of Japanese Patent Application No. 2022-109052, filed on July 6, 2022, is incorporated herein by reference in its entirety. In addition, all documents, patent applications, and technical standards described herein are incorporated by reference to the same extent as if each individual document, patent application, and technical standard were specifically and individually indicated as being incorporated by reference.

Claims (15)

Step A is a process for preparing a first laminate, in which a first resin layer, a first substrate, and a first inorganic material layer are laminated in that order, with the first resin layer on one surface and the first inorganic material layer on the other surface, and a second laminate, in which a second resin layer, a second substrate, and a second inorganic material layer are laminated in that order, with the second resin layer on one surface and the second inorganic material layer on the other surface, wherein the first resin layer is formed by thermosetting of a resin material including a thermosetting resin and a surface planarization treatment .
Step B involves bringing the first resin layer of the first laminate and the second inorganic material layer of the second laminate into contact to laminate the first laminate and the second laminate,
A method for manufacturing a substrate laminate, comprising step C, after step B, of heating the first laminate and the second laminate to 100°C or higher. The first laminate is provided with electrodes on a part of the surface of the first resin layer and a part of the surface of the first inorganic material layer.
The method for manufacturing a substrate laminate according to claim 1, wherein the second laminate is provided with electrodes on a part of the surface of the second resin layer and a part of the surface of the second inorganic material layer. The method for manufacturing a substrate laminate according to claim 2, comprising the step of applying a surface activation treatment to the second inorganic material layer before step B. A method for manufacturing a substrate laminate according to claim 1, further comprising the step of providing through holes in the first laminate and the second laminate from the surface on the first inorganic material layer side toward the surface on the second resin layer side after step C, and forming electrodes that penetrate the first laminate and the second laminate in the through holes. A method for manufacturing a substrate laminate according to any one of claims 1 to 4, comprising the step of cleaning the second inorganic material layer before step B. A method for manufacturing a substrate laminate according to any one of claims 1 to 4, comprising the step of providing a surface protective layer to the second inorganic material layer before step B. The method for manufacturing a substrate laminate according to any one of claims 1 to 4, wherein, before contacting the first resin layer and the second inorganic material layer in step B, the composite modulus of the first resin layer at 23°C is 0.1 GPa or more and 20 GPa or less. The method for manufacturing a substrate laminate according to any one of claims 1 to 4, wherein, before contacting the first resin layer with the second inorganic material layer in step B, the curing rate of the first resin layer is 70% or more and 100% or less. The method for manufacturing a substrate laminate according to any one of claims 1 to 4, wherein, before contacting the first resin layer and the second inorganic material layer in step B, the surface roughness (Ra) of the first resin layer is 0.01 nm or more and 1.2 nm or less. A method for manufacturing a substrate laminate according to any one of claims 1 to 4, wherein the surface of the first resin layer has at least one functional group selected from the group consisting of silanol groups, amino groups, epoxy groups, hydroxyl groups, and functional groups having unsaturated bonds. The first resin layer is
Siloxane bond and
A method for manufacturing a substrate laminate according to any one of claims 1 to 4, comprising at least one selected from the group consisting of ester bonds, ether bonds, amide bonds, and imide bonds. The method for manufacturing a substrate laminate according to any one of claims 1 to 4, wherein the second inorganic material layer contains at least one element selected from the group consisting of Si, Ga, Ge, and As. A method for manufacturing a substrate laminate according to any one of claims 1 to 4, wherein the planarization treatment is performed by a fly-cutting method or a chemical mechanical polishing method (CMP). A first laminate comprising a first resin layer, a first substrate, and a first inorganic material layer in this order, wherein the first resin layer is disposed on one surface and the first inorganic material layer is disposed on the other surface,
A second laminate comprising a second resin layer, a second substrate, and a second inorganic material layer in this order, wherein the second resin layer is disposed on one surface and the second inorganic material layer is disposed on the other surface,
It has,
The surface roughness (Ra) of the first resin layer is 0.1 nm or more and 1.0 nm or less.
A substrate laminate in which the first laminate and the second laminate are laminated together via the first resin layer of the first laminate and the second inorganic material layer of the second laminate. The first laminate is provided with electrodes on a part of the surface of the first resin layer and a part of the surface of the first inorganic material layer.
The substrate laminate according to claim 14 , wherein the second laminate is provided with electrodes on a part of the surface of the second resin layer and a part of the surface of the second inorganic material layer.