WO2025115877A1 - Adhesive composition and laminate - Google Patents

Abstract

Provided is an adhesive composition that contains: a compound (A) having an Si-O bond and a cationic functional group including at least one of a primary nitrogen atom and a secondary nitrogen atom; a crosslinking agent (B) which has a weight average molecular weight of 200-600 and has three or more -C(=O)OX groups in the molecule, where X denotes a hydrogen atom or an alkyl group having 1-6 carbon atoms, and one to six of the three or more -C(=O)OX groups is a -C(=O)OH group; and an additive (D) having a structure represented by formula (a) and a structure represented by formula (b). Also provided is a laminate.

Description

Adhesive composition and laminate

This disclosure relates to an adhesive composition and a laminate.

As electronic devices become smaller, lighter, and more powerful, there is a demand for higher integration of semiconductor chips with electrodes arranged on a substrate. However, it is difficult to fully meet the demand for higher integration by only miniaturizing the circuits. In recent years, a method has been proposed for achieving higher integration by stacking multiple semiconductor substrates to form a multi-layered three-dimensional structure.
As a method for stacking substrates (wafers), chips, etc. (hereinafter sometimes referred to as "substrates, etc."), a method for directly bonding substrates together (fusion bonding), a method for adhering substrates together using an adhesive, etc. have been proposed.
For example, Patent Document 1 (JP 2016-47895 A) describes an adhesive that does not exhibit adhesive properties during stacking operations of semiconductor chips and the like, but softens when heated to exhibit adhesive properties, and then quickly hardens.

Patent document 1: JP 2016-47895 A

In the examples of Patent Document 1, a laminate is produced by bonding a glass plate and a silicon plate using an adhesive, but there is no description of an example in which an adhesive is used to bond an inorganic material and an organic material.
Furthermore, in recent years, there has been a trend toward even higher integration of semiconductor chips. In addition to substrates made of inorganic materials, the use of substrates made of organic materials such as thermosetting resins (hereinafter also referred to as organic substrates) has been considered.
When an inorganic substrate is used, in order to improve the wettability of the adhesive, the substrate may be surface-treated with an organic solvent or a so-called leveling agent may be added to the adhesive composition.
On the other hand, when the organic substrate is subjected to a surface treatment using an organic solvent or the like, there is a concern that the surface of the resin substrate may be damaged, which is undesirable. Furthermore, a known leveling material added to the adhesive layer does not provide sufficient wettability to the organic substrate, and a uniform coating film cannot be obtained, particularly when a thin resin layer is formed, and foreign matter may be generated on the coating film surface.
An object of one embodiment of the present disclosure is to provide an adhesive composition that is capable of forming a uniform coating film even when an organic substrate is used, and a laminate using this adhesive composition.

Specific means for solving the above problems include the following aspects.
<1> An adhesive composition comprising: a compound (A) having a cationic functional group containing at least one selected from a primary nitrogen atom and a secondary nitrogen atom and a Si—O bond; a crosslinking agent (B) having three or more —C(═O)OX groups in the molecule, X representing a hydrogen atom or an alkyl group having from 1 to 6 carbon atoms, and of the three or more —C(═O)OX groups, one to six are —C(═O)OH groups, and having a weight average molecular weight of 200 or more and 600 or less; and an additive (D) having a structure represented by the following formula (a) and a structure represented by the following formula (b):

<2> The adhesive composition according to <1>, wherein a content of the additive (D) is 0.1 parts by mass or more and 7 parts by mass or less with respect to 100 parts by mass of a total content of the compound (A) and the crosslinking agent (B).
<3> The adhesive composition according to <1> or <2>, further comprising a polar solvent (C).
<4> The adhesive composition according to <3>, in which the polar solvent (C) contains at least water.
<5> The adhesive composition according to <3> or <4>, in which a content of the additive (D) is 0.01 parts by mass or more and 0.8 parts by mass or less, relative to 100 parts by mass of a total content of the compound (A), the crosslinking agent (B), and the polar solvent (C).

<6> A laminate comprising an inorganic material layer, an organic material layer, and an adhesive layer disposed between the inorganic material layer and the organic material layer and bonding the inorganic material layer to the organic material layer, the adhesive layer comprising the adhesive composition according to claim 1 or 2.
<7> A laminate comprising an inorganic material layer, an organic material layer, and an adhesive layer disposed between the inorganic material layer and the organic material layer and bonding the inorganic material layer and the organic material layer, the adhesive layer comprising: a reaction product of a compound (A) having a cationic functional group containing at least one selected from a primary nitrogen atom and a secondary nitrogen atom and a Si—O bond, and a crosslinking agent (B) having three or more —C(═O)OX groups (X is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms) in the molecule, wherein one to six of the three or more —C(═O)OX groups are —C(═O)OH groups, and having a weight average molecular weight of 200 to 600, and an additive (D) having a structure represented by the following formula (a) and a structure represented by the following formula (b):

<8> The adhesive composition according to any one of <1> to <5>, wherein the additive (D) has a structure represented by the following formula (c):

In formula (c), R ¹ and R ² each independently represent a hydrogen atom or an organic group having 1 to 10 carbon atoms.
n represents an integer of 1 to 40, m represents an integer of 1 to 30, x represents an integer of 1 to 300, and y represents an integer of 1 to 100.

According to one embodiment of the present disclosure, an adhesive composition capable of forming a uniform coating film even when an organic substrate is used, and a laminate using this adhesive composition are provided.

In the present disclosure, a numerical range expressed using "to" means a range that includes the numerical values before and after "to" as the lower and upper limits.
In the numerical ranges described in the present disclosure in stages, the upper or lower limit value described in one numerical range may be replaced with the upper or lower limit value of another numerical range described in stages. In addition, in the numerical ranges described in the present disclosure, the upper or lower limit value of the numerical range may be replaced with a value shown in the examples.
In the present disclosure, the term "laminate" refers to a structure in which an inorganic material layer, an adhesive layer, and an organic material layer are arranged in this order, and the inorganic material layer and the organic material layer are bonded via the adhesive layer.

<Adhesive Composition>
The adhesive composition of the present disclosure includes a compound (A) having a cationic functional group containing at least one selected from a primary nitrogen atom and a secondary nitrogen atom and a Si—O bond, a crosslinking agent (B) having three or more -C(═O)OX groups in the molecule, X representing a hydrogen atom or an alkyl group having from 1 to 6 carbon atoms, and of the three or more -C(═O)OX groups, one to six are -C(═O)OH groups, and having a weight average molecular weight of 200 or more and 600 or less, and an additive (D) having a structure represented by the following formula (a) and a structure represented by the following formula (b):

The adhesive composition contains the compound (A) and the crosslinking agent (B), and thus the adhesive property to an inorganic substrate and the adhesive strength after heating are improved.
Furthermore, when the adhesive composition contains the additive (D), the affinity of the adhesive composition to the resin substrate is improved.
The mechanism by which the affinity for the resin substrate is improved is not clear, but is presumed to be as follows.
It is believed that additive (D) containing a siloxane bond represented by formula (a) as a partial structure improves adhesion to inorganic materials and organic materials, and further, containing an ether bond represented by formula (b) causes the ether bond to be unevenly distributed on the organic substrate side in the adhesive composition, improving affinity with organic substrates; for example, even when the adhesive composition contains a polar solvent, repelling of the adhesive composition is suppressed when applied to an organic substrate, enabling the formation of a uniform coating film.
In a preferred embodiment of the present disclosure, it is presumed that the partial structure represented by formula (b) is present in the side chain of additive (D) to improve the mobility of the ether bond, to further improve the affinity to the resin substrate, and to provide superior coatability.

An example of the structure represented by formula (a) is the structure represented by formula (a-1) below.

In formula (a-1), R ⁰¹ and R ⁰² each independently represent a hydrogen atom, a hydrocarbon group having 1 to 10 carbon atoms, or a group represented by the following formula (a-2).

In formula (a-2), R ¹ and R ² each independently represent a hydrogen atom or an organic group having 1 to 10 carbon atoms.
In formula (a-2), when ^R1 and ^R2 represent an organic group having 1 to 10 carbon atoms, examples of the organic group include an aliphatic hydrocarbon group having 1 to 10 carbon atoms and an aromatic hydrocarbon group having 1 to 10 carbon atoms. Examples of the aliphatic hydrocarbon group include an alkyl group having 1 to 5 carbon atoms, such as a methyl group and an ethyl group, and examples of the aliphatic hydrocarbon group include a phenyl group.
In formula (a-2), x represents an integer of 1 to 300, preferably 1 to 280, more preferably 1 to 100, and even more preferably 1 to 50.
y represents an integer of 1 to 100, preferably 1 to 90, more preferably 1 to 50, and even more preferably 1 to 20.

In formula (a-1), when R ⁰¹ and R ⁰² represent an organic group having 1 to 10 carbon atoms, examples of the organic group include an aliphatic hydrocarbon group having 1 to 10 carbon atoms and an aromatic hydrocarbon group having 1 to 10 carbon atoms. Examples of the aliphatic hydrocarbon group include an alkyl group having 1 to 5 carbon atoms, such as a methyl group and an ethyl group, and examples of the aliphatic hydrocarbon group include a phenyl group.

In particular, the additive (D) may be a compound having a structure represented by the following formula (c):
According to formula (c), by having a siloxane bond represented by the above formula (a) in the main chain and an ether bond represented by formula (b) in the side chain, the adhesive composition can be more easily formed into a uniform coating film on an organic substrate.

In formula (c), R ¹ and R ² each independently represent a hydrogen atom or an organic group having 1 to 10 carbon atoms.
When ^R1 and ^R2 each represent an organic group having 1 to 10 carbon atoms, examples of the organic group include an aliphatic hydrocarbon group having 1 to 10 carbon atoms and an aromatic hydrocarbon group having 1 to 10 carbon atoms. More specific examples of the hydrocarbon group include alkyl groups such as a methyl group, an ethyl group, and a propyl group, and a phenyl group.
From the viewpoint of improving affinity with the organic substrate, it is particularly preferred that in formula (c), R ¹ is a hydrogen atom or a methyl group, and R ² is a methyl group or an ethyl group.
From the same viewpoint, in formula (c), n represents an integer of 1 to 40, preferably 1 to 38, and more preferably 1 to 10.
m represents an integer of 1 to 30, preferably 1 to 29, and more preferably 1 to 10.
x represents an integer of 1 to 300, preferably 1 to 280, more preferably 1 to 100, and even more preferably 1 to 50.
y represents an integer of 1 to 100, preferably 1 to 90, more preferably 1 to 50, and even more preferably 1 to 20.

The weight average molecular weight of additive (D) can be in the range of 500 to 5000, preferably 700 to 3000, more preferably 800 to 2000, and even more preferably 800 to 1000. When the weight average molecular weight of additive (D) is 500 or more, the affinity to the resin substrate is good, and when it is 5000 or less, the solubility during preparation of the adhesive composition and the uniformity in the solution are good.

In the present disclosure, the weight average molecular weight refers to the weight average molecular weight in terms of polyethylene glycol, measured by Gel Permeation Chromatography (GPC) for a substance other than the monomer.
Specifically, the weight average molecular weight is analyzed using tetrahydrofuran as a developing solvent, a Shodex DET RI-101 analyzer, and an analytical column (2x PLgel 5μ MIXED-D, 7.5 x 300 mm/40°C, manufactured by Agilent Technologies) at a flow rate of 1.0 mL/min to detect the refractive index, and polyethylene glycol/polyethylene oxide as a standard.

Exemplary compounds of the additive (D) and their weight average molecular weights are listed below by defining each partial structure in formula (c), but the additive (D) of the present disclosure is not limited thereto.
In the following formula (c), R ¹ represents a hydrogen atom or an alkyl group having 1 to 5 carbon atoms, and R ² represents an organic group having 1 to 10 carbon atoms.

 
 

Additive (D) may be a commercially available product. Examples of commercially available additive (D) that may be used in the adhesive composition of the present disclosure include silicone surface conditioners from BYK Japan Co., Ltd., such as BYK-333, BYK-307, BYK-302, BYK-325, BYK-331, BYK-342, BYK-345, BYK-346, BYK-347, BYK-348, BYK-349, BYK-378, BYK-3455, and BYK-3456.

The adhesive composition of the present disclosure contains at least a compound (A), a crosslinking agent (B), and an additive (D). Details of the compound (A) and the crosslinking agent (B) will be described later.
In the adhesive composition of the present disclosure, the content of the additive (D) is preferably 0.1 parts by mass or more and 7 parts by mass or less, relative to 100 parts by mass of the total content of the compound (A) and the crosslinking agent (B).
When the content of the additive (D) is within the above range, the adhesive composition has better ability to form a uniform coating film on an organic substrate. In particular, the content of the additive (D) is preferably 0.1 parts by mass or more and 7 parts by mass or less, more preferably 0.1 parts by mass or more and 5 parts by mass or less, and even more preferably 1 part by mass or more and 3 parts by mass or less, relative to 100 parts by mass of the total content of the compound (A) and the crosslinking agent (B) [hereinafter also referred to as (A+B)].

The adhesive composition of the present disclosure may further contain a polar solvent (C).
By including the polar solvent (C) in the adhesive composition of the present disclosure, the environmental impact is reduced and the composition can be more easily prepared.
The polar solvent (C) preferably contains at least water.
Generally, when an adhesive composition contains a polar solvent (C) such as water, the affinity to an organic substrate decreases, and repelling is likely to occur when the composition is applied to a resin substrate, but when the adhesive composition contains the additive (D), the occurrence of repelling is suppressed, and the uniform application to a resin substrate is improved. Therefore, it is considered that the adhesive composition of the present disclosure has a remarkable effect in an embodiment containing a polar solvent (C) as a solvent.
The polar solvent (C) will be described in detail below.

When the adhesive composition of the present disclosure further contains a polar solvent (C) in addition to the compound (A), the crosslinking agent (B), and the additive (D), the content of the additive (D) is preferably 0.01 parts by mass or more and 0.8 parts by mass or less per 100 parts by mass of the total content of the compound (A), the crosslinking agent (B), and the polar solvent (C).
When the content of the additive (D) is within the above range, the adhesive composition exhibits better formability of a uniform coating film on a resin substrate, even when the adhesive composition contains a polar solvent (C).
In particular, the amount is more preferably 0.1 parts by mass or more and 0.6 parts by mass or less, and even more preferably 0.1 parts by mass or more and 0.5 parts by mass or less, relative to 100 parts by mass of the total content of the compound (A), the crosslinking agent (B), and the polar solvent (C) [hereinafter, also referred to as (A+B+C)].

The adhesive composition of the present disclosure may contain only one type of additive (D), or may contain two or more types.
The content of the additive (D) relative to the total mass of the adhesive composition is preferably 0.1 mass % to 0.6 mass %, and more preferably 0.1 mass % to 0.5 mass %.

The following describes the inorganic material layer (inorganic substrate) and organic material layer (organic substrate) to which the adhesive composition of the present disclosure is applied.

(Inorganic material layer)
The adhesive composition of the present disclosure is disposed between an inorganic material layer and an organic material layer and is used to bond the inorganic material layer and the organic material layer.
There are no particular limitations on the type of inorganic material constituting the inorganic material layer to which the adhesive composition of the present disclosure is applied.
Specific examples of inorganic materials include semiconductors such as Si, InP, GaN, GaAs, InGaAs, InGaAlAs, SiGe, and SiC; oxides, carbides, and nitrides such as boron silicate glass (Pyrex (registered _trademark )), quartz glass ( _SiO2 ), sapphire ( _{Al2O3 )} , _ZrO2 , _Si3N4 , SiCN, AlN, _{and MgAl2O4} ; piezoelectrics or dielectrics such as _BaTiO3 , _LiNbO3 , _SrTiO3 , and _LiTaO3 ; diamond; metals such as Al, Ti, Fe, Cu, Ag, Au, Pt, Pd, Ta, and Nb; and carbon.
Among the above-mentioned inorganic materials, Si, SiO ₂ , SiC and SiCN are preferred.

The inorganic material layer may be a self-supporting object, or may be formed in a layer on the surface of another object. When the inorganic material layer is formed in a layer on the surface of another object, the type of the other object is not particularly limited, and may be an inorganic material or an organic material.
The inorganic material layer may have an electrode on the surface facing the organic material layer.

(Organic material layer)
There are no particular limitations on the type of organic material constituting the organic substrate (organic material layer) to which the adhesive composition of the present disclosure is applied.
Specific examples of the organic material include epoxy resin, phenol resin, silicone resin, polyimide, benzocyclobutene resin, and polybenzoxazole.

The organic material layer may be a self-supporting object, or may be formed in a layer on the surface of another object. When the organic material layer is formed in a layer on the surface of another object, the type of the other object is not particularly limited, and may be an inorganic material or an organic material.
The organic material layer may have an electrode on the surface facing the inorganic material layer.

The adhesive composition of the present disclosure contains at least the following compound (A) and crosslinking agent (B) in addition to the additive (D), and may further contain a polar solvent (C) as desired.
Compound (A): A compound having a cationic functional group containing at least one of a primary nitrogen atom and a secondary nitrogen atom and an Si—O bond. Crosslinking agent (B): A compound having three or more —C(═O)OX groups (X is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms) in the molecule, and one to six of the three or more —C(═O)OX groups are —C(═O)OH groups.

-Compound (A)-
Compound (A) has a cationic functional group containing at least one of a primary nitrogen atom and a secondary nitrogen atom. The cationic functional group is not particularly limited as long as it can bear a positive charge and contains at least one of a primary nitrogen atom and a secondary nitrogen atom.
The compound (A) may contain a tertiary nitrogen atom in addition to the primary and secondary nitrogen atoms.
The compound (A) preferably has two or three Si—O bonds.

In this disclosure, a "primary nitrogen atom" refers to a nitrogen atom that is bonded to only two hydrogen atoms and one atom other than a hydrogen atom (e.g., a nitrogen atom contained in a primary amino group ( _-NH2 group)), or a nitrogen atom that is bonded to only three hydrogen atoms and one atom other than a hydrogen atom (cation).
The term "secondary nitrogen atom" refers to a nitrogen atom bonded to only one hydrogen atom and two atoms other than hydrogen atoms (i.e., a nitrogen atom contained in a functional group represented by the following formula (a1)), or a nitrogen atom (cation) bonded to only two hydrogen atoms and two atoms other than hydrogen atoms.
The term "tertiary nitrogen atom" refers to a nitrogen atom bonded to only three atoms other than hydrogen atoms (i.e., a nitrogen atom that is a functional group represented by the following formula (b1)), or a nitrogen atom (cation) bonded to one hydrogen atom and only three atoms other than hydrogen atoms.

In formulae (a1) and (b1), * indicates the position of bonding to an atom other than a hydrogen atom.
The functional group represented by formula (a1) may be a functional group constituting a part of a secondary amino group (-NHR ^a group; here, R ^a represents an alkyl group), or may be a divalent linking group contained in the skeleton of a polymer.
The functional group represented by formula (b1) (i.e., a tertiary nitrogen atom) may be a functional group constituting a part of a tertiary amino group (-NR ^b R ^c group; here, R ^b and R ^c each independently represent an alkyl group), or may be a trivalent linking group contained in the skeleton of a polymer.

The weight average molecular weight of compound (A) is preferably 130 or more and 10,000 or less, more preferably 130 or more and 5,000 or less, and even more preferably 130 or more and 2,000 or less.

In the present disclosure, the weight average molecular weight of a compound refers to the weight average molecular weight in terms of polyethylene glycol measured by GPC (Gel Permeation Chromatography) method.
Specifically, the weight-average molecular weight of the compound is calculated using an aqueous solution of sodium nitrate having a concentration of 0.1 mol/L as a developing solvent, detecting the refractive index at a flow rate of 1.0 mL/min using an analytical device Shodex DET RI-101 and two types of analytical columns (TSKgel G6000PWXL-CP and TSKgel G3000PWXL-CP, both manufactured by Tosoh), and using polyethylene glycol/polyethylene oxide as standards with analytical software (Empower3, manufactured by Waters).

The compound (A) may further have an anionic functional group, a nonionic functional group, or the like, as necessary.
The nonionic functional group may be a hydrogen bond accepting group or a hydrogen bond donating group. Examples of the nonionic functional group include a hydroxyl group, a carbonyl group, and an ether group (-O-).
The anionic functional group is not particularly limited as long as it is a functional group that can bear a negative charge. Examples of the anionic functional group include a carboxylic acid group, a sulfonic acid group, and a sulfate group.

The compound (A) may be a compound having a Si—O bond and an amino group.
Examples of compounds having an Si--O bond and an amino group include siloxane diamine, a silane coupling agent having an amino group, and a siloxane polymer.
An example of the silane coupling agent having an amino group is a compound represented by the following formula (A-3).

In formula (A-3), R ¹ represents an alkyl group having 1 to 4 carbon atoms which may be substituted. ^{R 2} and R ³ each independently represent an alkylene group having 1 to 12 carbon atoms, an ether group, or a carbonyl group which may be substituted (the skeleton may contain a carbonyl group, an ether group, etc.). ^{R 4} and R ⁵ each independently represent an alkylene group having 1 to 4 carbon atoms which may be substituted or a single bond. Ar represents a divalent or trivalent aromatic ring. X ¹ represents hydrogen or an alkyl group having 1 to 5 carbon atoms which may be substituted. X ² represents hydrogen, a cycloalkyl group, a heterocyclic group, an aryl group, or an alkyl group having 1 to 5 carbon atoms which may be substituted (the skeleton may contain a carbonyl group, an ether group, etc.). A plurality of R ¹ , R ² , R ³ , R ⁴ , R ⁵ , and X ¹ may be the same or different.
Substituents of the alkyl and alkylene groups in ^R1 , ^R2 , ^R3 , ^R4 , ^R5 , ^X1 and ^X2 each independently include an amino group, a hydroxy group, an alkoxy group, a cyano group, a carboxylic acid group, a sulfonic acid group and halogens.
Examples of the divalent or trivalent aromatic ring in Ar include a divalent or trivalent benzene ring. Examples of the aryl group in ^X2 include a phenyl group, a methylbenzyl group, and a vinylbenzyl group.

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, (amino ethylaminoethyl)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 having an amino group other than that represented by 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,
Examples of the silyl group include 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 hydrolysates thereof.

The above-mentioned silane coupling agents having an amino group may be used alone or in combination of two or more. A silane coupling agent having an amino group may also be used in combination with a silane coupling agent not having an amino group. For example, a silane coupling agent having a mercapto group may be used to improve adhesion to metals.

Compound (A) may be a polymer (siloxane polymer) formed from the above-mentioned silane coupling agent via a siloxane bond (Si-O-Si). For example, a polymer having a linear siloxane structure, a polymer having a branched siloxane structure, a polymer having a cyclic siloxane structure, a polymer having a cage siloxane structure, etc. can be obtained from the hydrolyzate of 3-aminopropyltrimethoxysilane. The cage siloxane structure is represented, for example, by the following formula (A-1).

Examples of siloxane diamines 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.

Siloxane diamines 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).

Since compound (A) has a cationic functional group containing at least one of a primary nitrogen atom and a secondary nitrogen atom, it can strongly adhere to the surface of the inorganic material layer and/or the organic material layer by electrostatic interaction with functional groups such as hydroxyl groups, epoxy groups, carboxy groups, amino groups, and mercapto groups that may be present on the surface of the inorganic material layer and/or the organic material layer, or by forming a covalent bond with the functional groups.

Compound (A) has a cationic functional group containing at least one of a primary nitrogen atom and a secondary nitrogen atom, and therefore is easily soluble in polar solvent (C). By using compound (A) that is easily soluble in polar solvent (C), when the surface of the inorganic material layer or organic material layer is hydrophilic, the affinity with these surfaces is increased. As a result, a smooth adhesive layer can be formed.

It is preferable that the molar ratio (non-crosslinkable group/Si element) of the Si element in the molecule to the non-crosslinkable group such as a methyl group bonded to the Si element in the compound (A) is less than 2 (satisfying the relationship: non-crosslinkable group/Si element<2). By satisfying this condition, it is believed that the crosslinking density (crosslinking between Si-O-Si bonds and amide bonds, imide bonds, etc.) of the formed film is improved, resulting in excellent bonding strength.

When compound (A) contains a primary nitrogen atom, the proportion of primary nitrogen atoms in the total nitrogen atoms in compound (A) is preferably 20 mol% or more, more preferably 25 mol% or more, and even more preferably 30 mol% or more. Compound (A) may also have a cationic functional group that contains a primary nitrogen atom and does not contain any nitrogen atoms other than the primary nitrogen atom (e.g., secondary nitrogen atom, tertiary nitrogen atom).

When compound (A) contains secondary nitrogen atoms, the ratio of secondary nitrogen atoms to the total nitrogen atoms in compound (A) is preferably 5 mol% or more and 50 mol% or less, and more preferably 10 mol% or more and 45 mol% or less.

Compound (A) may contain a tertiary nitrogen atom in addition to a primary nitrogen atom and a secondary nitrogen atom. When compound (A) contains a tertiary nitrogen atom, the ratio of tertiary nitrogen atoms to the total nitrogen atoms in compound (A) is preferably 20 mol % or more and 50 mol % or less, and more preferably 25 mol % or more and 45 mol % or less.

The content of compound (A) in the composition is not particularly limited, but can be, for example, 0.001% by mass or more and 20% by mass or less, preferably 0.01% by mass or more and 20% by mass or less, and more preferably 0.04% by mass or more and 20% by mass or less, relative to the entire composition.

-Crosslinking agent (B)-
The crosslinking agent (B) is a compound having three or more -C(=O)OX groups (X is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms) in the molecule, preferably a compound having three to six -C(=O)OX groups in the molecule, and more preferably a compound having three or four -C(=O)OX groups in the 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, and among these, a hydrogen atom, a methyl group, an ethyl group, or a propyl group is preferred. Note that X in the -C(=O)OX group may be the same or different.

The crosslinking agent (B) is a compound having 1 to 6 -C(=O)OH groups in which X is a hydrogen atom in the molecule, preferably 1 to 4 -C(=O)OH groups in the molecule, more preferably 2 to 4 -C(=O)OH groups in the molecule, and even more preferably 2 or 3 -C(=O)OH groups in the molecule.

The weight average molecular weight of the compound (B) is not particularly limited. For example, the weight average molecular weight of the compound (B) may be 200 or more and 600 or less, 200 or more and 500 or less, 200 or more and 450 or less, or 200 or more and 400 or less.
When the weight average molecular weight of the compound (B) is within the above range, the solubility in the composition is improved.

It is preferable that the crosslinking agent (B) has a ring structure in the molecule. Examples of the ring structure include an alicyclic structure and an aromatic ring structure. The crosslinking agent (B) may have multiple ring structures in the molecule, and the multiple ring structures may be the same or different. When the compound (B) has a ring structure in the molecule, the heat resistance of the adhesive layer is improved.

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

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

The ring structure that the crosslinking agent (B) has in its molecule 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, and from the viewpoint of further increasing the heat resistance of the adhesive layer, at least one of a benzene ring and a naphthalene ring is more preferable.

As mentioned above, the crosslinking agent (B) may have multiple ring structures in the molecule, and when the ring structure is benzene, it may have a biphenyl structure, a benzophenone structure, a diphenyl ether structure, etc.

The crosslinking agent (B) may have a fluorine atom in the molecule. For example, it may have 1 to 6 fluorine atoms in the molecule, or 3 to 6 fluorine atoms in the molecule. For example, the compound (B) may have a fluoroalkyl group in the molecule, specifically, it may have a trifluoroalkyl group or a hexafluoroisopropyl group. If the crosslinking agent (B) has a fluorine atom in the molecule, the water absorption of the adhesive layer decreases.

Examples of the crosslinking agent (B) include carboxylic acid compounds such as alicyclic carboxylic acids, benzene carboxylic acids, naphthalene carboxylic acids, diphthalic acids, and fluorinated aromatic carboxylic acids, and carboxylic acid ester compounds such as alicyclic carboxylic acid esters, benzene carboxylic acid esters, naphthalene carboxylic acid esters, diphthalic acid esters, and fluorinated aromatic carboxylic acid esters.

The carboxylate compound is a compound having a carboxy group (-C(=O)OH group) in the molecule, and having 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).
When the crosslinking agent (B) contained in the adhesive is a carboxylate compound, aggregation due to association between the compound (A) and the crosslinking agent (B) in the composition is suppressed, and aggregates and pits in the cured product are reduced, resulting in an adhesive layer with higher smoothness and making it easier to adjust the thickness of the adhesive layer.

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

The carboxylate compound is preferably a compound containing three or less carboxy groups (-C(=O)OH groups) and three or less ester bonds in the molecule, and more preferably a compound containing two or less carboxy groups and two or less ester bonds in the molecule.

In the carboxylate compound, when X in three or more -C(=O)OX groups is an alkyl group having 1 to 6 carbon atoms, X is preferably a methyl group, an ethyl group, a propyl group, or a butyl group, and from the viewpoint of further suppressing aggregation due to association between compound (A) and crosslinking agent (B) in the composition, X is preferably an ethyl group or a propyl group.

Specific examples of the carboxylic acid compound include, 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; benzene carboxylic acids such as 1,2,4-benzenetricarboxylic acid, 1,3,5-benzenetricarboxylic acid, pyromellitic acid, benzenepentacarboxylic acid, and mellitic acid; naphthalene carboxylic acids such as 1,4,5,8-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- diphthalic acid (4,4'-(Ethylene-1,2-diyl)diphthalic acid), 4,4'-(1,4-phenylenebis(oxy))diphthalic acid (4,4'-(1,4-phenylenebis(oxy))diphthalic acid), 4,4'-([1,1'-biphenyl]-4,4'-diylbis(oxy))diphthalic acid (4,4'([1,1'-biphenyl]-4,4'-diylbis(oxy))diphthalic acid), 4,4'-((oxybis(4,1-phenylene))bis(oxy)) Examples of such fluorinated aromatic carboxylic acids include diphthalic acid (4,4'-(oxybis(4,1-phenylene))bis(oxy))diphthalic 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 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 compound include compounds in which at least one carboxy group in the specific examples of the carboxylic acid compound described above has been replaced with an ester group. Examples of the carboxylic acid ester compound include half-esterified compounds represented by the following formulas (B-1) to (B-6).

In formulae (B-1) to (B-6), R is an alkyl group having 1 to 6 carbon atoms, and among these, a methyl group, an ethyl group, a propyl group, or a butyl group is preferable, and an ethyl group or a propyl group is more preferable.
In the formula (B-2), Y is O, C=O or C( _CF3 ) ₂ .

A half-esterified compound can be produced, for example, by mixing a carboxylic acid anhydride, which is the anhydride of the aforementioned carboxylic acid compound, with an alcohol solvent and opening the ring of the carboxylic acid anhydride.

The content of the crosslinking agent (B) in the composition is, for example, preferably an amount such that the ratio (COOH/N) of the number of carboxy groups in the crosslinking agent (B) to the total number of nitrogen atoms in the compound (A) is 0.1 or more and 3.0 or less, more preferably an amount such that the ratio is 0.3 or more and 2.5 or less, and even more preferably an amount such that the ratio is 0.4 or more and 2.2 or less. By using a composition in which the COOH/N ratio is 0.1 or more and 3.0 or less, a crosslinked structure such as an amide bond or an imide bond is sufficiently formed between the compound (A) and the crosslinking agent (B) after heat treatment, and an adhesive layer with excellent heat resistance and insulating properties is formed.

When the composition contains an amine compound as a component other than compound (A) and crosslinking agent (B), the ratio (COOH/N) of the number of carboxy groups in crosslinking agent (B) to the total number of all nitrogen atoms contained therein and in compound (A) is preferably 0.1 or more and 3.0 or less.

From the viewpoint of leaving little unreacted crosslinking agent (B), the content ratio (feed ratio) of the compound (A) to the crosslinking agent (B) in the composition is preferably a molar ratio of compound (A):crosslinking agent (B) of 2:0.9 to 2:1.1, and more preferably a molar ratio of 2:1.
It is believed that the compound (A) and the crosslinking agent (B) in the composition exist as a mixture in a state in which the amino group of the compound (A) and the carboxy group of the crosslinking agent (B) form a salt in the polar solvent (C).
A cured product obtained by heating a composition containing compound (A) and crosslinking agent (B) is considered to contain, as a structural unit, a reaction product between compound (A) and crosslinking agent (B) as exemplified below.

-Polar solvent (C)-
The adhesive composition of the present disclosure may further contain a polar solvent (C).
In the present disclosure, a "polar solvent" refers to a solvent having a relative dielectric constant of 5 or greater at room temperature (25° C.).
When the composition contains the polar solvent (C), the solubility of each component in the composition is improved.
The polar solvent (C) may be used alone or in combination of two or more kinds.

Specific examples of the polar solvent (C) include protic solvents 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 cyclohexanone; acid derivatives such as ethyl acetate, butyl acetate, ethylene carbonate, propylene carbonate, formaldehyde, N-methylformamide, N,N-dimethylformamide, N-methylacetamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, and hexamethylphosphoric acid amide; nitriles such as acetonitrile and propionitrile; and nitro compounds such as nitromethane and nitrobenzene; and sulfur compounds such as dimethyl sulfoxide.
The polar solvent (C) preferably contains a protic solvent, more preferably contains water, and further preferably contains ultrapure water as the water.

The content of the polar solvent (C) in the composition is not particularly limited, and may be, for example, 1.0% by mass or more and 99.99896% by mass or less, or 40% by mass or more and 99.99896% by mass or less, relative to the entire composition.

From the viewpoint of volatilizing the polar solvent (C) by heating the composition and reducing the amount of residual solvent in the composition, the boiling point of the polar solvent (C) is preferably 150°C or lower, and more preferably 120°C or lower.

-Other ingredients-
The composition may contain known additives (also referred to as other additives) other than the additive (D) described above.
Examples of other additives include an acid having a carboxy group and a weight average molecular weight of 46 to 195, a base having a nitrogen atom and no ring structure and a weight average molecular weight of 17 to 120, and a solvent other than the polar solvent (C).

The composition may contain a solvent other than the polar solvent (C). Examples of the solvent other than the polar solvent include normal hexane.

The composition may contain benzotriazole or a derivative thereof, for example to inhibit copper corrosion.

The pH of the composition is not particularly limited, but is preferably from 2.0 to 12.0.
When the pH of the composition is 2.0 or more and 12.0 or less, damage to the substrate caused by the composition is suppressed.
The composition preferably contains 10 ppb by mass or less of sodium and potassium on an elemental basis, respectively. If the content of sodium or potassium is 10 ppb by mass or less on an elemental basis, the occurrence of problems in the electrical characteristics of the semiconductor device, such as malfunction of a transistor, can be suppressed.

When the composition contains components other than the compound (A), the crosslinking agent (B), and the additive (D), the total content of the compound (A) and the crosslinking agent (B) is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more of the total mass of the nonvolatile content in the composition. In this disclosure, "nonvolatile content" refers to components other than components (solvents, etc.) that are removed when the composition becomes a cured product.

-Method of producing the composition-
The method for producing the composition is not particularly limited, and can be carried out by a known method.
For example, the composition can be produced by a method including the following steps (a), (b) and (c).
Step (a): A step of mixing compound (A) with water to obtain solution A containing a hydrolysate of compound (A); Step (b): A step of adding alcohol to a precursor of crosslinking agent (B), heating and refluxing to prepare solution B containing a half ester compound of crosslinking agent (B); Step (c): A step of blending solution A, solution B, additive (D), and optionally polar solvent (C).

The composition can be cured by heating to form an adhesive layer.
The heating temperature for curing the composition is preferably 150° C. to 450° C., more preferably 150° C. to 400° C., and even more preferably 180° C. to 400° C. The above temperature refers to the temperature of the surface of the composition.

The heating time of the composition is not particularly limited and may be, for example, 3 hours or less or 1 hour or less. The lower limit of the heating time is not particularly limited and may be, for example, 5 minutes or more.
In order to shorten the heating time, the composition may be irradiated with ultraviolet (UV) rays.

Whether the composition is cured after heating can be confirmed, for example, by measuring the peak intensity of specific bonds and structures by Fourier transform infrared spectroscopy (FT-IR). Examples of the specific bonds and structures include bonds and structures generated by a crosslinking reaction.
For example, when amide bonds, imide bonds, etc. are formed in the composition, it can be determined that the composition is cured.
The presence or absence of an amide bond can be confirmed by the presence or absence of vibration peaks at about 1650 cm ^-1 and about 1520 cm ^-1 .
The presence or absence of an imide bond can be confirmed by the presence or absence of vibration peaks at about 1770 cm ^-1 and about 1720 cm ^-1 .

<Laminate>
A first embodiment of the laminate of the present disclosure has an inorganic material layer, an organic material layer, and an adhesive layer disposed between the inorganic material layer and the organic material layer and bonding the inorganic material layer to the organic material layer, the adhesive layer containing the adhesive composition of the present disclosure described above.

The laminate of the present disclosure has an inorganic material layer and an organic material layer bonded together via an adhesive layer formed from the adhesive composition of the present disclosure, and the adhesive layer exhibits excellent adhesion to both the inorganic material layer and the organic material layer due to the function of the adhesive composition.

A second embodiment of the laminate of the present disclosure includes an inorganic material layer, an organic material layer, and an adhesive layer disposed between the inorganic material layer and the organic material layer to bond the inorganic material layer and the organic material layer, the adhesive layer including a reaction product of a compound (A) having a cationic functional group containing at least one selected from a primary nitrogen atom and a secondary nitrogen atom and an Si-O bond, and a crosslinking agent (B) having three or more -C(=O)OX groups (X is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms) in the molecule, of which one to six of the three or more -C(=O)OX groups are -C(=O)OH groups, and having a weight average molecular weight of 200 to 600, and an additive (D) having a structure represented by the following formula (a) and a structure represented by the following formula (b).

From the viewpoint of ensuring sufficient bonding strength to the inorganic material layer and the organic material layer, the ratio (X/Y) of the die shear strength X (MPa) between the inorganic material layer and the organic material layer to the thickness Y (μm) of the adhesive layer is preferably 1.2 or more, more preferably 1.5 or more, and even more preferably 2.0 or more.
The upper limit of the ratio (X/Y) of the die shear strength X (MPa) between the inorganic material layer and the organic material layer to the thickness Y (μm) of the adhesive layer is not particularly limited, and may be, for example, 10 or less, 8 or less, or 6 or less.

In this disclosure, the die shear strength between the inorganic material layer and the organic material layer is measured by the method described in the Examples.

From the viewpoint of ensuring sufficient bonding strength to the inorganic material layer and the organic material layer, the thickness Y of the adhesive layer is preferably 0.2 μm or more, more preferably 0.5 μm or more, and further preferably 1.0 μm or more.
From the viewpoint of ensuring sufficient heat dissipation, the thickness Y of the adhesive layer is preferably 10 μm or less, more preferably 7.5 μm or less, further preferably 5.0 μm or less, and even more preferably 3.0 μm or less.

In this disclosure, the thickness of the adhesive layer is measured by the method described in the Examples.

From the viewpoint of ensuring sufficient bonding strength between the inorganic material layer and the organic material layer, the die shear strength X between the inorganic material layer and the organic material layer is preferably 3 MPa or more, more preferably 4 MPa or more, and even more preferably 5 MPa or more.

The upper limit of the die shear strength X between the inorganic material layer and the organic material layer is not particularly limited, but may be, for example, 10 MPa or less, 8 MPa or less, or 6 MPa or less.

The adhesive layer preferably contains a cured adhesive. When the adhesive layer contains a cured adhesive, the adhesive layer is sufficiently hard, and misalignment when bonding the inorganic material layer and the organic material layer can be effectively suppressed. When bonding the inorganic material layer and the organic material layer, the adhesive layer may be in a completely cured state or in a not completely cured state.

From the viewpoint of suppressing the generation of voids due to outgassing, the curing rate of the adhesive 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. In addition, the curing rate of the adhesive layer may be 100%, 99% or less, 95% or less, or 90% or less.

The curing rate of the adhesive layer may be confirmed, for example, by measuring the peak intensity of a specific bond and structure (the sum of the peak intensities when there are multiple peaks such as imide, amide, etc.) using FT-IR (Fourier transform infrared spectroscopy) in the adhesive layer to be measured and in the fully cured adhesive layer obtained by fully curing the adhesive layer, and determining the rate of increase or decrease in the peak intensity. Note that when there are band-like peaks that are difficult to separate, such as siloxane bonds, the maximum peak intensity may be used.

Specifically, when specific bonds and structures are generated by the curing reaction, the increase rate of the peak strength may be calculated by the following formula, and the calculated value may be regarded as the curing rate of the adhesive layer.
Peak strength increase rate (curing rate of adhesive layer) = [(peak strength of specific bonds and structures of adhesive layer to be measured) / (peak strength of specific bonds and structures of completely cured adhesive layer obtained by heating adhesive layer to be measured at 300 ° C. for 1 hour)] × 100
The background signal can be removed by a conventional method. If necessary, the FT-IR measurement can be performed by a transmission method or a reflection method.

In the above-mentioned rate of increase in peak intensity, if there are multiple bonds and structures resulting from the increase in peak intensity, the peak intensity may be interpreted as the total intensity of the multiple peak intensities.

<Method of manufacturing laminate>
There are no particular limitations on the method for producing the laminate of the present disclosure.
For example, a step of applying the adhesive composition of the present disclosure to a surface of at least one of an organic material layer and an inorganic material layer to form an adhesive composition layer;
bonding the inorganic material layer and the organic material layer via the adhesive composition layer;
The composition can be produced by a method comprising the steps of:

In the above method, the method for applying the adhesive composition to the surface of at least one of the organic material layer and the inorganic material layer is not particularly limited, and can be carried out by a known method.
For example, it may be performed by a spin coating method, an ink jet method, a screen printing method, or the like.

When forming an adhesive composition layer by applying an adhesive composition to the surface of an organic material layer, the surface of the organic material layer on which the adhesive composition layer is formed may be in a state where it has been subjected to plasma treatment. By performing plasma treatment, for example, the wettability of the adhesive to the organic material layer is further improved.

In the above method, the method for bonding the inorganic material layer and the organic material layer via the adhesive layer is not particularly limited.
For example, a method in which the adhesive layer disposed between the organic material layer and the inorganic material layer is pressurized while being heated can be mentioned.
The temperature at which the adhesive layer is heated is not particularly limited and can be selected depending on the type of adhesive. The temperature at which the adhesive layer is heated may be, for example, 150° C. or higher, 200° C. or higher, or 400° C. or lower, or 300° C. or lower.
The pressure to be applied to the adhesive layer is not particularly limited and can be selected depending on the type of adhesive.

In the above method, the step of forming the adhesive layer may include a step of curing the adhesive. That is, the adhesive layer may be in a state including a cured product of the adhesive when the inorganic material layer and the organic material layer are bonded together. In the step of curing the adhesive, the adhesive may or may not be completely cured.
When the inorganic material layer and the organic material layer are bonded together, if the adhesive layer contains a cured product of the adhesive, it is possible to effectively prevent misalignment when bonding the inorganic material layer and the organic material layer. Furthermore, the adhesive layer has low adhesion when bonding the inorganic material layer and the organic material layer, and the bonding operation can be performed efficiently.

The method for curing the adhesive is not particularly limited and can be selected depending on the composition of the adhesive composition.
For example, when the adhesive composition is cured by heating to form an adhesive layer, the heating temperature is not particularly limited, but can be, for example, 150° C. or higher and 350° C. or lower.
The laminate of the present disclosure has good uniformity for application to an organic substrate, which is an organic material layer, and therefore can reliably bond an organic substrate to an inorganic substrate, which is an inorganic material layer, and can be applied to a variety of applications.

The present invention will be explained in detail below with reference to examples, but the present invention is not limited to these examples.

Example 1
(1) Preparation of Adhesive Composition 50% by mass of 3-aminopropyldiethoxymethylsilane (3APDES: structure below: compound (A)) and 50% by mass of water (polar solvent (c)) were blended to obtain a solution A containing a hydrolysate of 3APDES.

A solution B containing 70% by mass of ethyl oxydiphthalate half ester (eheODPA: crosslinking agent (B)) and 30% by mass of ethanol was obtained.
eheODPA was produced by adding oxydiphthalic anhydride (ODPA: structure shown below) to ethanol, refluxing for 5 hours in an oil bath heated to 90° C., and completely dissolving the raw material powder. It was confirmed by proton NMR that an ester group was formed in the produced eheODPA.

The obtained solution A (24 g), solution B (15.6 g), 1-propanol (20 g), water (40.4 g), and additive (D-1) (additive (D)) were mixed together to prepare an adhesive composition. The above-mentioned exemplary compound (D-1) was used as additive (D-1).

<Examples 2 to 5, Comparative Examples 1 and 2>
An adhesive composition was prepared in the same manner as in Example 1, except that the components of the adhesive composition were changed to those shown in Table 1 below.

(2) Formation of Adhesive Layer on Organic Substrate An epoxy resin composition (R4121-2C) manufactured by Nagase ChemteX Corporation was molded under the following conditions to obtain an epoxy resin substrate.
Mold: 125°C x 400 seconds Post mold cure: 150°C x 30 minutes

The adhesive composition prepared in (1) above was applied onto an epoxy resin substrate by spin coating and dried for 1 minute at 150° C. Then, the substrate was heated for 1 hour at 200° C. in a nitrogen atmosphere to form an adhesive layer.
The adhesive composition spread over the entire surface of the epoxy resin substrate without any gaps and there were no uncoated defects, so it was determined that a uniform coating film (adhesive layer) was formed on the organic substrate (epoxy resin substrate).

<Evaluation criteria for coatability on organic substrates>
By visual observation, a substrate in which the adhesive composition had spread over the entire surface of the epoxy resin substrate (organic substrate) without any gaps, had no uncoated defects, and formed a uniform coating film was rated as A, whereas a substrate in which the adhesive composition had not spread over some parts of the epoxy resin substrate (organic substrate) (i.e., repelling) had occurred, and a uniform coating film was not formed was rated as B.
The results are shown in Table 2.

(2) Formation of Adhesive Layer on Inorganic Substrate The adhesive composition prepared in (1) above was applied onto a 4-inch φ silicon substrate (inorganic substrate) by spin coating, and dried at 150° C. for 1 minute. Thereafter, the adhesive layer was formed by heating at 200° C. for 1 hour in a nitrogen atmosphere.
The adhesive composition spread over the entire surface of the 4-inch diameter silicon substrate without any gaps, and there were no uncoated defects, so it was determined that a uniform coating film (adhesive layer) was formed on the inorganic substrate (4-inch substrate).

<Evaluation Criteria for Coating Properties on Inorganic Substrates>
By visual observation, a substrate in which the adhesive composition had spread over the entire surface of a 4-inch φ silicon substrate (inorganic substrate) without any gaps, there were no uncoated defects, and a uniform coating film had been formed was rated as A, whereas a substrate in which the adhesive composition had not spread over part of the 4-inch φ silicon substrate (inorganic substrate) (i.e., repelling) had occurred, and a uniform coating film had not been formed was rated as B.
The results are shown in Table 2.

(3) Preparation of a substrate laminate for evaluating bonding strength A 4-inch diameter silicon substrate was prepared as a first substrate. The silicon substrate was treated with UV ozone for 5 minutes, and then the composition prepared in (1) above was spin-coated thereon.
After drying at 150° C. for 1 minute, the coating was heated at 200° C. for 1 hour in a nitrogen atmosphere to form a film (adhesive layer) containing imide cross-linked siloxane.
A silicon substrate, which was a second substrate, was attached to the adhesive layer side obtained above at room temperature for temporary fixation. The temporary fixation was temporary bonding in a room temperature (25° C.) atmosphere.

<Evaluation criteria for bond strength in room temperature temporary bonding>
During the above room temperature temporary bonding, the case where the bonded silicon substrates were fixed to each other was rated as A, and the case where the bonded silicon substrates were not fixed to each other was rated as B.
The results are shown in Table 2.

After the above temporary bonding at room temperature, the substrates were heated in an inert oven at 200° C. for 1 hour to produce a substrate laminate consisting of a first substrate/adhesive layer/second substrate.
According to the method of non-patent document (MP Maszara, G. Goetz, A. Cavigila, and JB Mckitterick, Journal of Applied Physics, 64 (1988) 4943-4950), the surface energy (bonding strength) of the bonding interface of the substrate laminate was measured by a blade insertion test.
A blade with a thickness of 0.1 mm to 0.3 mm was inserted into the bonding interface of the substrate laminate, and the distance from the blade tip to the substrate laminate peeled off was measured using an infrared light source and an infrared camera, and then the surface energy was measured 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 substrate such as the silicon substrate contained in the first substrate stack and the second substrate, etc., t represents the thickness (m) of the substrate in the first substrate stack and the substrate in the second substrate, etc., and L represents the laminate peeling distance (m) from the blade tip.

<Evaluation criteria for bonding strength after heating (baking)>
When the surface energy measured above was 2.5 J/ ^m2 or more, it was evaluated as A, and when the surface energy was less than 2.5 J/ ^m2 , it was evaluated as B.
The results are shown in Table 2.

As shown in Table 2, in Examples 1 to 5 in which the adhesive composition of the present disclosure was used, the coatability to organic substrates was good in addition to the coatability to inorganic substrates, and it was possible to form uniform coating films on both inorganic and organic substrates.
On the other hand, in Comparative Examples 1 and 2, which did not contain the additive (D), repelling occurred when applied to the organic substrate, and a uniform coating film could not be formed.

The disclosure of Japanese Patent Application No. 2023-203350, filed on November 30, 2023, is incorporated herein by reference.
All publications, patent applications, and standards mentioned in this disclosure are incorporated by reference into this disclosure to the same extent as if each individual publication, patent application, or standard was specifically and individually indicated to be incorporated by reference.

Claims (8)

a compound (A) having a cationic functional group containing at least one selected from a primary nitrogen atom and a secondary nitrogen atom and a Si—O bond;
a crosslinking agent (B) having three or more -C(=O)OX groups in the molecule, X representing a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and among the three or more -C(=O)OX groups, one to six are -C(=O)OH groups, and having a weight average molecular weight of 200 to 600;
and an additive (D) having a structure represented by the following formula (a) and a structure represented by the following formula (b),
Adhesive composition.




The adhesive composition according to claim 1, wherein the content of the additive (D) is 0.1 parts by mass or more and 7 parts by mass or less per 100 parts by mass of the total content of the compound (A) and the crosslinking agent (B). The adhesive composition according to claim 1, further comprising a polar solvent (C). The adhesive composition according to claim 3, wherein the polar solvent (C) contains at least water. The adhesive composition according to claim 3, wherein the content of the additive (D) is 0.01 parts by mass or more and 0.8 parts by mass or less per 100 parts by mass of the total content of the compound (A), the crosslinking agent (B), and the polar solvent (C). an inorganic material layer, an organic material layer, and an adhesive layer disposed between the inorganic material layer and the organic material layer to bond the inorganic material layer and the organic material layer;
A laminate, wherein the adhesive layer comprises the adhesive composition according to claim 1 or 2. an inorganic material layer, an organic material layer, and an adhesive layer disposed between the inorganic material layer and the organic material layer to bond the inorganic material layer and the organic material layer;
The adhesive layer is
A reaction product of a compound (A) having a cationic functional group containing at least one selected from a primary nitrogen atom and a secondary nitrogen atom and a Si—O bond, and a crosslinking agent (B) having three or more —C(═O)OX groups (X is a hydrogen atom or an alkyl group having 1 to 6 carbon atoms) in the molecule, of which one to six of the three or more —C(═O)OX groups are —C(═O)OH groups, and having a weight average molecular weight of 200 to 600, and
A laminate comprising an additive (D) having a structure represented by the following formula (a) and a structure represented by the following formula (b):


The adhesive composition according to claim 1 or 2, wherein the additive (D) has a structure represented by the following formula (c):


In formula (c), ^R1 and ^R2 each independently represent a hydrogen atom or an organic group having 1 to 10 carbon atoms, n represents an integer of 1 to 40, m represents an integer of 1 to 30, x represents an integer of 1 to 300, and y represents an integer of 1 to 100.