Laminate

Abstract

A laminate according to the present invention includes a polyimide resin layer on a substrate that is surface-modified with a compound having an oxy-silyl group, wherein the compound having an oxy-silyl group is at least one selected from the group consisting of compounds having a succinic anhydride structure and compounds having a primary amino group, a polyimide resin constituting the polyimide resin layer has an alicyclic structure, and the glass-transition temperature of the polyimide resin is 300°C or higher.

Description

Laminate

[0001] This invention relates to a laminate and a method for manufacturing a laminate.

[0002] With the increasing integration of semiconductors, it has become important to planarize the insulating film on the wafer surface in semiconductor processes in order to improve patterning accuracy in high resolution, miniaturization, and multilayer wiring, and to improve the accuracy of bonding between wafers. Polyimide resins have excellent mechanical properties, heat resistance, and insulating properties, and are being considered for various uses in fields such as electrical and electronic components, and are also being attempted to be used as the insulating film mentioned above. For example, Patent Document 1 discloses a planarization process for forming an insulating film with good planarization characteristics by applying a composition containing a fully imidized polyimide polymer and a solvent onto a substrate having a conductive metal pattern.

[0003] Special table 2022-550611 publication

[0004] Although polyimide resins possess excellent properties as described above, there are several challenges in using them as insulating films, particularly planarization films, in the semiconductor field. For example, silicon wafers used in the semiconductor field have few functional groups on their surface, making it difficult to achieve good adhesion with resins. Furthermore, achieving both heat resistance and adhesion has been extremely difficult. For example, modifying the resin with functional groups, adding additives, or increasing the fluidity of the resin to improve adhesion deteriorates heat resistance. The present invention has been made in view of these circumstances, and the object of the present invention is to provide a laminate with excellent heat resistance and adhesion.

[0005] The present inventors have discovered that the above problems can be solved by a laminate having a polyimide resin layer having a specific structure and a glass transition temperature of 300°C or higher on a substrate that has undergone specific surface modification, and have completed the invention.

[0006] In other words, the present invention relates to the following [1] to

[15] . [1] A laminate having a polyimide resin layer on a substrate surface-modified with a compound having an oxysilyl group, wherein the compound having an oxysilyl group is at least one selected from the group consisting of compounds having a succinic anhydride structure and compounds having a primary amino group, the polyimide resin constituting the polyimide resin layer has an alicyclic structure, and the glass transition temperature of the polyimide resin is 300°C or higher. [2] The laminate according to [1], wherein an inorganic film made of silicon oxide or silicon nitride is provided on the polyimide resin layer. [3] The laminate according to [2], wherein the thickness of the inorganic film is 1 to 1,000 nm. [4] The laminate according to any one of [1] to [3], wherein the polyimide resin has at least one selected from the group consisting of the structural unit of formula (3), the structural unit of formula (4), and the structural unit of formula (5). [5] The laminate according to [4], wherein the polyimide resin further has structural units of the following formula (6). [6] The laminate according to any one of [1] to [5], wherein the thickness of the polyimide resin layer is 0.5 to 300 μm. [7] The laminate according to any one of [1] to [6], wherein the substrate is silicon, silicon carbide, gallium nitride, gallium oxide, aluminum nitride, or diamond. [8] The laminate according to any one of [1] to [7], wherein the compound having an oxysilyl group is at least one selected from the group consisting of a compound represented by the following general formula (1), a compound represented by the following general formula (2), and a compound having a melamine-like structure and an oxysilyl group. (In formula (1), R 1 This is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a phenyl group, or an aminoalkyl group having 1 to 6 carbon atoms, and has three R 1 They may be different. In equation (2), R 2 This is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a phenyl group, or an aminoalkyl group having 1 to 6 carbon atoms, and has three R 2 They may be different.) [9] R 1 is a methyl group, R 2The laminate according to [8], wherein the group is a methyl group or an ethyl group.

[10] A method for producing a laminate, comprising the steps of: applying a solution containing a compound having an oxysilyl group and a solvent onto a substrate, firing it to obtain a substrate surface-modified with the compound having an oxysilyl group; and applying a polyimide resin varnish containing a polyimide resin and a solvent onto the surface-modified substrate and heating it to obtain a polyimide resin layer, wherein the compound having an oxysilyl group is at least one selected from the group consisting of compounds having a succinic anhydride structure and compounds having a primary amino group, the polyimide resin has an alicyclic structure, and the glass transition temperature of the polyimide resin is 300°C or higher.

[11] The method for producing a laminate according to

[10] , wherein the solvent contained in the polyimide resin varnish contains at least one selected from the group consisting of 1,3-dimethyl-2-imidazolidinone and γ-butyrolactone.

[12] A method for manufacturing a laminate according to

[10] or

[11] , further comprising the step of laminating an inorganic film made of silicon oxide or silicon nitride on the polyimide resin layer.

[13] A method for manufacturing a laminate according to any one of

[10] to

[12] , wherein the polyimide resin has at least one selected from the group consisting of structural units of formula (3), formula (4), and formula (5).

[14] The method for manufacturing the laminate according to

[13] , wherein the polyimide resin further has a structural unit of the following formula (6).

[15] A method for manufacturing a laminate according to any one of

[10] to

[14] , wherein the substrate is silicon, silicon carbide, gallium nitride, gallium oxide, aluminum nitride, or diamond.

[0007] According to the present invention, a laminate with excellent heat resistance and adhesion can be provided. Furthermore, a method for manufacturing a laminate that can obtain a laminate with excellent heat resistance and adhesion can be provided. Because the laminate of the present invention has the above properties, it is useful as a laminate in semiconductor processes.

[0008] [Laminate] The laminate of the present invention has a polyimide resin layer on a substrate surface-modified with a compound having an oxysilyl group, wherein the compound having an oxysilyl group is at least one selected from the group consisting of compounds having a succinic anhydride structure and compounds having a primary amino group, the polyimide resin constituting the polyimide resin layer has an alicyclic structure, and the glass transition temperature of the polyimide resin is 300°C or higher.

[0009] <Substrate> The laminate of the present invention has a substrate surface-modified with a compound having an oxysilyl group, wherein the compound having an oxysilyl group is at least one selected from the group consisting of compounds having a succinic anhydride structure and compounds having a primary amino group. The compound having an oxysilyl group is at least one selected from the group consisting of compounds having a succinic anhydride structure and compounds having a primary amino group, but from the viewpoint of adhesion and heat resistance, it is preferably a compound having a primary amino group.

[0010] The oxysilyl group in a compound having an oxysilyl group is preferably at least one selected from the group consisting of a hydrocarbyloxysilyl group and a silanol group, more preferably a hydrocarbyloxysilyl group, and even more preferably an alkoxysilyl group.

[0011] Among the compounds having an oxysilyl group, the compounds having a succinic anhydride structure are compounds having an oxysilyl group with a succinic anhydride structure, and are preferably compounds represented by the following general formula (1).

[0012] Among the compounds having an oxy-silyl group, the compound having a primary amino group is a compound having a primary amino group and an oxy-silyl group, preferably a compound represented by the following general formula (2), a compound having a melamine-like structure and an oxy-silyl group, and at least one selected from the group consisting of polymers having two or more primary amino groups and two or more oxy-silyl groups. More preferably, it is at least one selected from the group consisting of a compound represented by the following general formula (2) and a compound having a melamine-like structure and an oxy-silyl group. Even more preferably, it is a compound represented by the following general formula (2), and even more preferably, it is aminoalkyltrialkoxysilane.

[0013] The compound having a melamine-like structure and an oxy-silyl group is preferably a trialkoxysilane having a melamine-like structure, such as "VD-5" manufactured by Shikoku Kasei Kogyo Co., Ltd. The polymer having two or more primary amino groups and two or more oxy-silyl groups is preferably a polymer having two or more primary amino groups and two or more trialkoxysilyl groups, such as "X-12-972F" manufactured by Shin-Etsu Chemical Co., Ltd.

[0014] Thus, the compound having an oxy-silyl group is preferably at least one selected from the group consisting of a compound represented by the following general formula (1), a compound represented by the following general formula (2), and a compound having a melamine-like structure and an oxy-silyl group. (In formula (1), R 1 is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a phenyl group, or an aminoalkyl group having 1 to 6 carbon atoms, and the three Rs 1 may be different. In formula (2), R 2 is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a phenyl group, or an aminoalkyl group having 1 to 6 carbon atoms, and the three Rs 2 may be different.)

[0015] The compound having the oxysilyl group is preferably at least one selected from the group consisting of compounds represented by general formula (1), compounds represented by general formula (2), and compounds having a melamine-like structure and an oxysilyl group. More preferably, from the viewpoint of adhesion and heat resistance, it is at least one selected from the group consisting of compounds represented by formula (2) and compounds having a melamine-like structure and an oxysilyl group, and even more preferably, it is the compound represented by formula (2).

[0016] In equation (1), R 1 This is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a phenyl group, or an aminoalkyl group having 1 to 6 carbon atoms, and has three R 1 They may be different. 1 Preferably, it is at least one selected from the group consisting of a hydrogen atom, a C1-C6 alkyl group, a phenyl group, and a C1-C6 aminoalkyl group, more preferably a C1-C6 alkyl group, even more preferably a C1-C2 alkyl group (methyl group or ethyl group), and even more preferably a C1 alkyl group (methyl group).

[0017] In equation (2), R 2 This is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a phenyl group, or an aminoalkyl group having 1 to 6 carbon atoms, and has three R 2 They may be different. 2 Preferably, R is at least one selected from the group consisting of a hydrogen atom, a C1-C6 alkyl group, a phenyl group, and a C1-C6 aminoalkyl group, more preferably a C1-C6 alkyl group, even more preferably a C1-C2 alkyl group (methyl group or ethyl group), and even more preferably a C1 alkyl group (methyl group). As described above, preferably R 1 is a methyl group and R 2 is a methyl group or an ethyl group, more preferably R 1 is a methyl group and R 2 This is a methyl group.

[0018] The substrate (the substrate before surface modification) is preferably silicon, silicon carbide, gallium nitride, gallium oxide, aluminum nitride, or diamond, and more preferably silicon. The above-mentioned substrate may also be silicon oxide, silicon nitride, or a substrate on which an interlayer insulating layer (Low-k film) is formed. Furthermore, the substrate may have steps due to metal wiring, such as Cu wiring, or steps due to the arrangement of chips such as memory and logic chips.

[0019] It is believed that the surface of a substrate surface-modified with the compound having the oxysilyl group contains at least one structure selected from the group consisting of, for example, the structure represented by the following formula (1s) and the structure represented by the following formula (2s).

[0020] <Polyimide Resin Layer and Polyimide Resin> The laminate of the present invention has a polyimide resin layer on the substrate. The polyimide resin layer functions as a planarizing film for planarizing the surface of the substrate. Planarizing treatments such as CMP and grinding may be performed as needed. It also functions as an insulating film. The polyimide resin constituting the polyimide resin layer has an alicyclic structure, and the glass transition temperature of the polyimide resin is 300°C or higher.

[0021] The thickness of the polyimide resin layer is preferably 0.5 to 300 μm, more preferably 1 to 100 μm, even more preferably 2 to 60 μm, even more preferably 3 to 40 μm, and even more preferably 5 to 30 μm. When the thickness of the polyimide resin layer is within the above range, good insulation properties are obtained.

[0022] The glass transition temperature of the polyimide resin is 300°C or higher. Preferably, the glass transition temperature of the polyimide resin is 350°C or higher, more preferably 400°C or higher, even more preferably 430°C or higher, even more preferably 440°C or higher, and even more preferably 450°C or higher. There is no upper limit, but it is preferably 550°C or lower. The glass transition temperature of the polyimide resin being within the above range results in the laminate of the present invention having excellent heat resistance and is useful as a laminate in semiconductor processes.

[0023] Although the reason why the laminate of the present invention is excellent in heat resistance and adhesion is not clear, it is considered as follows. The polyimide resin used in the laminate of the present invention is considered to have excellent heat resistance because it contains a rigid alicyclic structure without a rotating site. Further, the laminate of the present invention forms a bond with the resin by being treated with a compound having a specificoxysilyl group, and is considered to have strong adhesion that does not peel off from the support substrate even in a planarization process such as polishing or a high-temperature and high-humidity environment while also having excellent heat resistance as a laminate.

[0024] The polyimide resin has an alicyclic structure. The polyimide resin has an alicyclic structure, preferably has at least one selected from the group consisting of a structural unit of the following formula (3), a structural unit of the following formula (4), and a structural unit of the following formula (5), more preferably has at least one selected from the group consisting of a structural unit of the following formula (3) and a structural unit of the following formula (5), and still more preferably has a structural unit of the following formula (3). The polyimide resin is considered to have excellent heat resistance while showing excellent solubility in a rinse solution because it contains a structure derived from a specific dianhydride having a rigid alicyclic structure without a rotating site.

[0025] The polyimide resin preferably further has a structural unit of the following formula (6). By including the above structure, the resin forming the polyimide resin layer has excellent adhesion and particularly excellent heat resistance.

[0026] <Each structural unit of the polyimide resin> The polyimide resin has a structural unit A derived from a tetracarboxylic dianhydride and a structural unit B derived from a diamine. In the polyimide resin, the structural unit A and the structural unit B form an imide structure. Next, each structural unit will be described.

[0027] (Structural unit A) The structural unit A is a structural unit derived from a tetracarboxylic dianhydride. The structural unit A preferably includes a structural unit derived from an alicyclic tetracarboxylic dianhydride.

[0028] As the alicyclic tetracarboxylic dianhydride that provides a structural unit derived from an alicyclic tetracarboxylic dianhydride, preferably cyclohexane-1,2,4,5-tetracarboxylic dianhydride (HPMDA), bicyclo[2.2.2]octane-2,3:5,6-tetracarboxylic dianhydride, decahydro-1,4:5,8-dimethanonaphthalene-2,3,6,7-tetracarboxylic dianhydride (DNDA), cyclohexane-1,2,3,4-tetracarboxylic dianhydride, 1,2,3,4-cyclobutanetetracarboxylic dianhydride, 1,2,3,4-cyclopentanetetracarboxylic dianhydride, 1,2,4,5-cyclopentanetetracarboxylic dianhydride, 3,3',4,4'-bicyclohexyltetracarboxylic dianhydride, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydride, 5,5'-(1,4-phenylene)-bis[hexahydro-4,7-Methanoisobenzofuran-1,3-dione], 5,5'-bis-2-norbornene-5,5',6,6'-tetracarboxylic acid-5,5',6,6'-dianhydride, norbornane-2-spiro-α-cyclopentanone-α'-spiro-2''-norbornane-5,5',6,6'-tetracarboxylic anhydride (CpODA), 2,2-propylidene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, oxy-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic dianhydride, bicyclo[4.4.0]decane-2,3,6,7-tetracarboxylic dianhydride, etc. can be mentioned.

[0029] Among the constituent units derived from the alicyclic tetracarboxylic dianhydride, the following constituent units are more preferred. Therefore, constituent unit A more preferably includes at least one selected from the group consisting of constituent units (A3) derived from the compound represented by the following formula (a3), constituent unit (A4) derived from the compound represented by the following formula (a4), and constituent unit (A5) derived from the compound represented by the following formula (a5), and even more preferably includes at least one selected from the group consisting of constituent units (A3) derived from the compound represented by the following formula (a3) ​​and constituent unit (A5) derived from the compound represented by the following formula (a5), and even more preferably includes constituent unit (A3) derived from the compound represented by the following formula (a3). Furthermore, constituent unit A is even more preferably at least one selected from the group consisting of constituent units (A3) derived from the compound represented by the following formula (a3), constituent unit (A4) derived from the compound represented by the following formula (a4), and constituent unit (A5) derived from the compound represented by the following formula (a5).

[0030] The compound represented by formula (a3) ​​is cyclohexane-1,2,4,5-tetracarboxylic dianhydride (HPMDA). By using the constituent unit (A3) derived from the compound represented by formula (a3) ​​as a constituent unit of the polyimide resin, heat resistance and adhesion can be further enhanced. The compound represented by formula (a4) is bicyclo[2.2.2]octane-2,3:5,6-tetracarboxylic dianhydride. By using the constituent unit (A4) derived from the compound represented by formula (a4) as a constituent unit of the polyimide resin, heat resistance and adhesion can be further enhanced. The compound represented by formula (a5) is decahydro-1,4:5,8-dimethanonaphthalene-2,3,6,7-tetracarboxylic dianhydride (DNDA). By using the constituent unit (A5) derived from the compound represented by formula (a5) as a constituent unit of the polyimide resin, heat resistance and adhesion can be further enhanced.

[0031] If constituent unit A includes at least one selected from the group consisting of constituent units (A3), (A4), and (A5), the total ratio of constituent units (A3), (A4), and (A5) in constituent unit A is preferably 70 mol% or more and 100 mol% or less from the viewpoint of heat resistance and adhesion. More preferably it is 80 mol% or more and 100 mol% or less, even more preferably 90 mol% or more and 100 mol% or less, even more preferably 95 mol% or more and 100 mol% or less, even more preferably 99 mol% or more and 100 mol% or less, and may also be 100 mol%.

[0032] The ratio of constituent unit (A3) in constituent unit A is preferably 40 mol% or more, more preferably 50 mol% or more, even more preferably 60 mol% or more, even more preferably 70 mol% or more, even more preferably 80 mol% or more, even more preferably 90 mol% or more, and may also be 100 mol%.

[0033] The ratio of constituent unit (A4) in constituent unit A is preferably 40 mol% or more, more preferably 50 mol% or more, even more preferably 60 mol% or more, even more preferably 70 mol% or more, even more preferably 80 mol% or more, even more preferably 90 mol% or more, and may also be 100 mol%.

[0034] The ratio of constituent unit (A5) in constituent unit A is preferably 40 mol% or more, more preferably 50 mol% or more, even more preferably 60 mol% or more, even more preferably 70 mol% or more, even more preferably 80 mol% or more, even more preferably 90 mol% or more, and may also be 100 mol%.

[0035] Constituent unit A may include constituent units other than those derived from alicyclic tetracarboxylic dianhydrides. Such constituent units are not particularly limited, but include constituent units derived from aromatic tetracarboxylic dianhydrides and constituent units derived from aliphatic tetracarboxylic dianhydrides, and among these, constituent units derived from aromatic tetracarboxylic dianhydrides are preferred.

[0036] Aromatic tetracarboxylic dianhydrides that provide constituent units derived from aromatic tetracarboxylic dianhydrides include pyromellitic anhydride (PMDA), 3,3',4,4'-diphenylsulfonetetracarboxylic dianhydride (DSDA), p-biphenylenebis(trimellitic monoester anhydride) (BP-TME), 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA), 9,9-bis(trifluoromethyl)-9H-xanthen-2,3,6,7-tetracarboxylic dianhydride (6FCDA), 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]hexafluoropropane dianhydride, 3,3',4,4'-biphenyltetracarboxylic dianhydride (s-BPDA), 2,3,3',4'-biphenyltetracarboxylic dianhydride (a-BPDA), 4,4'-oxydiphthalic anhydride (ODPA), and 9,9'- Bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF), hydroquinone diphthalic anhydride (HQDPA), ethylene glycol bis(trimellitate) dianhydride (TMEG), p-phenylene bis(trimellitate) dianhydride (TAHQ), 4,4'-(hexafluoroisopropylidene) diphthalic anhydride (6FDA), 2,2-bis(3,4-dicarboxyphenyl)-propane dianhydride, spiro Examples include 11H-difluoro[3,4-b:3',4'-i]xanthene-11,9'-[9H]fluorene]-1,3,7,9-tetron (SFDA), 4,4'-thiodiphthalic anhydride, 5-[4-(1,3-dioxo-2-benzofuran-5-yl)phenyl]-2-benzofuran-1,3-dione, and 5-[3-(1,3-dioxo-2-benzofuran-5-yl)phenyl]-2-benzofuran-1,3-dione.

[0037] Among these, constituent unit A more preferably includes constituent unit (A6) derived from a compound represented by the following formula (a6).

[0038] The compound represented by formula (a6) is pyromellitic anhydride (PMDA). By using the constituent unit (A6) derived from the compound represented by formula (a6) as the constituent unit of the polyimide resin, heat resistance and adhesion can be further enhanced.

[0039] When constituent unit A includes at least one selected from the group consisting of constituent units (A3), (A4), and (A5), and constituent unit (A6), the ratio of the total of constituent units (A3), (A4), (A5), and (A6) in constituent unit A is preferably 70 mol% or more and 100 mol% or less from the viewpoint of heat resistance and adhesion. More preferably it is 80 mol% or more and 100 mol% or less, even more preferably 90 mol% or more and 100 mol% or less, even more preferably 95 mol% or more and 100 mol% or less, even more preferably 99 mol% or more and 100 mol% or less, and may be 100 mol%, with 100 mol% being even more preferable.

[0040] When constituent unit A includes at least one selected from the group consisting of constituent units (A3), (A4), and (A5), and constituent unit (A6), the molar ratio [((A3) + (A4) + (A5)) / (A6)] of the total content of constituent units (A3), (A4), and (A5) to the content of constituent unit (A6) is preferably 55 / 45 to 90 / 10, more preferably 60 / 40 to 85 / 15, even more preferably 60 / 40 to 80 / 20, and even more preferably 65 / 35 to 75 / 25. By having the molar ratio within the above range, heat resistance and adhesion can be further enhanced, and heat resistance in particular can be improved.

[0041] Examples of aliphatic tetracarboxylic dianhydrides that provide constituent units derived from aliphatic tetracarboxylic dianhydrides include 1,2,3,4-butanetetracarboxylic dianhydride. The constituent units optionally included in constituent unit A may be one type or two or more types. In this specification, aromatic tetracarboxylic dianhydride means a tetracarboxylic dianhydride containing one or more aromatic rings, alicyclic tetracarboxylic dianhydride means a tetracarboxylic dianhydride containing one or more alicyclic rings but not aromatic rings, and aliphatic tetracarboxylic dianhydride means a tetracarboxylic dianhydride that does not contain either aromatic or alicyclic rings.

[0042] (Constituent Unit B) Constituent unit B is a constituent unit derived from a diamine. Constituent unit B is not particularly limited as long as it is a constituent unit derived from a diamine. Constituent unit B preferably includes at least one selected from the group consisting of a constituent unit (B1) derived from 9,9-bis(4-aminophenyl)fluorene (BAFL) (b1) and a constituent unit (B2) derived from 4,4'-bis(4-aminophenoxy)biphenyl (BODA) (b2), from the viewpoint of heat resistance and adhesion, and more preferably includes a constituent unit (B1) derived from 9,9-bis(4-aminophenyl)fluorene (b1).

[0043] The ratio of constituent unit (B1) in constituent unit B is preferably 40 mol% or more, more preferably 50 mol% or more, even more preferably 60 mol% or more, even more preferably 70 mol% or more, even more preferably 80 mol% or more, even more preferably 90 mol% or more, and may be 100 mol%, with 100 mol% being even more preferable.

[0044] The ratio of constituent unit (B2) in constituent unit B is preferably 40 mol% or more, more preferably 50 mol% or more, even more preferably 60 mol% or more, even more preferably 70 mol% or more, even more preferably 80 mol% or more, even more preferably 90 mol% or more, and may be 100 mol%, with 100 mol% being even more preferable.

[0045] When constituent unit B includes constituent unit (B1) and constituent unit (B2), the total ratio of constituent unit (B1) to constituent unit (B2) in constituent unit B is preferably 70 mol% or more and 100 mol% or less from the viewpoint of heat resistance and adhesion. More preferably it is 80 mol% or more and 100 mol% or less, even more preferably 90 mol% or more and 100 mol% or less, even more preferably 95 mol% or more and 100 mol% or less, even more preferably 99 mol% or more and 100 mol% or less, and may be 100 mol%, with 100 mol% being even more preferable.

[0046] When constituent unit B contains constituent unit (B1) and constituent unit (B2), the molar ratio [(B1) / (B2)] of the content of constituent unit (B1) to the content of constituent unit (B2) is preferably 35 / 65 to 80 / 20, more preferably 40 / 60 to 70 / 30, even more preferably 40 / 60 to 60 / 40, and even more preferably 40 / 60 to 50 / 50. By having the molar ratio within the above range, heat resistance and adhesion can be further enhanced.

[0047] Constituent unit B may include constituent units other than constituent units (B1) and (B2). Examples of diamines that provide such constituent units are not particularly limited, but include aromatic diamines, alicyclic diamines, and aliphatic diamines, excluding 9,9-bis(4-aminophenyl)fluorene (BAFL) (b1) and 4,4'-bis(4-aminophenoxy)biphenyl (BODA) (b2). Examples of aromatic diamines include 4-aminophenyl-4-aminobenzoate (4-BAAB), bis(4-aminophenyl)terephthalate (APTP), 1,4-bis(4-aminobenzoyloxy)benzene, 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl ether (6FODA), 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (2,2'-TFMB), and 3,3'-bis(trifluoromethyl)- 4,4'-diaminobiphenyl, 2,2'-bis(trifluoromethyl)-5,5'-diaminobiphenyl, 2,2-bis(4-aminophenyl)hexafluoropropane (HFDA), 2,2-bis(3-amino-4-methylphenyl)hexafluoropropane, 2,2-bis[4-(4-aminophenoxy)phenyl]hexafluoropropane (HFBAPP), 4,4'-diaminodiphenyl ether (4,4'-ODA), 3,4'-diaminodi Phenylen ether, 4,4'-diaminodiphenylmethane (DDM), 4,4'-diaminodiphenyl sulfone (4,4'-DDS), 3,3'-diaminodiphenyl sulfone (3,3'-DDS), 4,4'-diamino-2,2'-dimethylbiphenyl (mTB), 4,4'-diaminobiphenyl (benzidine), 4,4'-diamino-3,3'-dimethylbiphenyl, 4,4'-diaminodiphenyl sulfide, 4,4'-diaminobenzophenone, 2,2-bis(3-aminophenyl)propane, 2,2-bis(4-aminophenyl)propane, 5-amino-1,3,3-trimethyl-1-(4-aminophenyl)-indan (5-TMDM), 6-amino-1,3,3-trimethyl-1-(4-aminophenyl)-indan (6-TMDM), 1,3-bis(3-amino-α,α-dimethylbenzyl)benzene, 1,3-bis(4-amino-α,α-dimethylbenzyl)benzene (BisAM), 1,4-bis(4-amino-α,α-dimethylbenzyl)benzene (BisAP), 4,4'-bis(3-aminophenoxy)biphenyl, 1,1-bis[4-(4-aminophenoxy)phenyl]cyclohexane, 2,2-bis[4-(4-aminophenoxy)phenyl]propane (BAPP), 1,4-bis(3-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, bis[4-(3-aminophenoxy)phenyl]ketone Examples include bis[4-(4-aminophenoxy)phenyl]ketone, bis[4-(3-aminophenoxy)phenyl]sulfide, bis[4-(4-aminophenoxy)phenyl]sulfide, bis[4-(3-aminophenoxy)phenyl]ether, bis[4-(4-aminophenoxy)phenyl]ether, bis[4-(3-aminophenoxy)phenyl]sulfone, bis[4-(4-aminophenoxy)phenyl]sulfone, 4,4-diaminobenzanilide, 4-aminobenzoic acid-4-aminophenyl, 3,4-diaminobenzanilide, etc. Examples of alicyclic diamines include 1,3-bis(aminomethyl)cyclohexane (1,3-BAC), 1,4-bis(aminomethyl)cyclohexane, 1,3-cyclohexyldiamine, 1,4-cyclohexyldiamine, isophoronediamine, bis(aminomethyl)norbornane, 4,4'-diaminodicyclohexylmethane, 4,4'-diaminodicyclohexyl ether, and 2,2-bis(4-aminocyclohexyl)propane. Examples of aliphatic diamines include ethylenediamine and hexamethylenediamine. In this specification, aromatic diamine means a diamine containing one or more aromatic rings, alicyclic diamine means a diamine containing one or more alicyclic rings but not aromatic rings, and aliphatic diamine means a diamine containing neither aromatic nor alicyclic rings. The constituent units optionally included in constituent unit B may be one type or two or more types.

[0048] The polyimide resin may contain structures other than polyimide chains (structures in which constituent unit A and constituent unit B are bonded by imide bonds) to the extent that it does not impair the present invention. Examples of structures other than polyimide chains that may be contained in the polyimide resin include structures containing amide bonds. It is preferable that the polyimide resin contains polyimide chains (structures in which constituent unit A and constituent unit B are bonded by imide bonds) as its main structure. Therefore, the ratio of polyimide chains in the polyimide resin is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 99% by mass or more, and even more preferably 100% by mass.

[0049] <Inorganic Film> The laminate of the present invention preferably comprises a substrate surface-modified with a compound having an oxysilyl group, a polyimide resin layer on the substrate, and further preferably an inorganic film on the polyimide resin layer. The inorganic film preferably contains silicon, and more preferably consists of silicon oxide or silicon nitride. The inorganic film is an insulating film. That is, the inorganic film functions as an insulating film and barrier film in the laminate, and also functions as a buffer film.

[0050] The thickness of the inorganic film is preferably 1 to 1,000 nm, more preferably 1 to 400 nm, even more preferably 10 to 300 nm, and even more preferably 20 to 200 nm.

[0051] [Method for Manufacturing the Laminate] The laminate of the present invention may be obtained by any manufacturing method as long as it has the above configuration, but it is preferably manufactured by the following method, and this manufacturing method is also included in the present invention.

[0052] The present invention provides a method for producing a laminate, comprising the steps of: applying a solution containing a compound having an oxysilyl group and a solvent onto a substrate, firing it to obtain a substrate surface-modified with the compound having an oxysilyl group; and applying a polyimide resin varnish containing a polyimide resin and a solvent onto the surface-modified substrate, and heating it to obtain a polyimide resin layer, wherein the compound having an oxysilyl group is at least one selected from the group consisting of compounds having a succinic anhydride structure and compounds having a primary amino group, the polyimide resin has an alicyclic structure, and the glass transition temperature of the polyimide resin is 300°C or higher.

[0053] In this manufacturing method, the compound having an oxysilyl group, the substrate, the polyimide resin layer, and the polyimide resin are as described above in this specification, and the preferred range is also as described above in this specification. Therefore, the polyimide resin in this manufacturing method is the same as the polyimide resin constituting the polyimide resin layer described above, and the preferred range is also as described above.

[0054] To give a specific example, preferably, the polyimide resin has at least one selected from the group consisting of the structural unit of formula (3), the structural unit of formula (4), and the structural unit of formula (5). More preferably, the polyimide resin further has the structural unit of formula (6).

[0055] <Step to obtain a surface-modified substrate> In this manufacturing method, first, a solution containing a compound having an oxysilyl group and a solvent is applied to the substrate, and then the substrate is fired to obtain a substrate whose surface has been modified with the compound having an oxysilyl group.

[0056] (Solution) The solution comprises a compound having an oxysilyl group and a solvent.

[0057] The compound having the oxysilyl group is preferably at least one selected from the group consisting of the compound represented by general formula (1), the compound represented by general formula (2), and the compound having a melamine-like structure and an oxysilyl group. More preferably, from the viewpoint of heat resistance and adhesion, it is at least one selected from the group consisting of the compound represented by formula (2) and the compound having a melamine-like structure and an oxysilyl group, and even more preferably the compound represented by formula (2).

[0058] In equation (1), R 1 This is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a phenyl group, or an aminoalkyl group having 1 to 6 carbon atoms, and has three R 1 They may be different. 1 Preferably, it is at least one selected from the group consisting of a hydrogen atom, a C1-C6 alkyl group, a phenyl group, and a C1-C6 aminoalkyl group, more preferably a C1-C6 alkyl group, even more preferably a C1-C2 alkyl group (methyl group or ethyl group), and even more preferably a C1 alkyl group (methyl group).

[0059] In equation (2), R 2 This is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a phenyl group, or an aminoalkyl group having 1 to 6 carbon atoms, and has three R 2 They may be different. 2 Preferably, R is at least one selected from the group consisting of a hydrogen atom, a C1-C6 alkyl group, a phenyl group, and a C1-C6 aminoalkyl group, more preferably a C1-C6 alkyl group, even more preferably a C1-C2 alkyl group (methyl group or ethyl group), and even more preferably a C1 alkyl group (methyl group). As described above, preferably R 1 is a methyl group and R 2 is a methyl group or an ethyl group, more preferably R 1 is a methyl group and R 2 This is a methyl group.

[0060] The solvent contained in the solution is preferably a solvent that can dissolve the compound having the oxysilyl group and remove it by calcination. The solvent is preferably at least one selected from the group consisting of isopropyl alcohol, methanol, ethanol, propylene glycol monomethyl ether (PGME), propylene glycol 1-monomethyl ether 2-acetate (PGMEA), methyl 2-hydroxyisobutyrate, cyclopentanone, cyclohexanone, and a mixed solvent of the above solvent and water. More preferably, it is at least one selected from the group consisting of isopropyl alcohol, propylene glycol monomethyl ether (PGME), methanol, and ethanol, and even more preferably isopropyl alcohol.

[0061] The concentration of the compound having an oxysilyl group in the solution is preferably 0.01 to 0.5% by mass, more preferably 0.02 to 0.3% by mass, and even more preferably 0.05 to 0.2% by mass.

[0062] (Substrate) The substrate (substrate before surface modification) is preferably silicon, silicon carbide, gallium nitride, gallium oxide, aluminum nitride, or diamond, and more preferably silicon. The above-mentioned substrate may be a substrate on which a silicon oxide layer, a silicon nitride layer, and an interlayer insulating layer (Low-k film) are formed.

[0063] (Surface modification method) After applying the solution onto the substrate, the substrate surface is modified with a compound having an oxysilyl group by firing. There are no restrictions on the method of applying the solution onto the substrate. Known application methods include spin coating, slit coating, and blade coating. Among these, spin coating is preferred from the viewpoint of improving film uniformity and workability.

[0064] The calcination process involves removing the solvent, reacting the compound containing the oxysilyl group with the substrate surface, and modifying the substrate surface with the compound containing the oxysilyl group.

[0065] The firing temperature is preferably 70 to 300°C, more preferably 80 to 200°C, even more preferably 90 to 150°C, and even more preferably 95 to 120°C. The firing time is preferably 30 seconds to 10 hours, more preferably 1 minute to 1 hour, and even more preferably 2 to 30 minutes. Firing may be performed only once, or the substrate may be cooled after firing and reheated, and the firing process may be repeated two or more times.

[0066] <Step to obtain a polyimide resin layer> In this manufacturing method, following the above step, a polyimide resin varnish is applied to the surface-modified substrate and heated to obtain a polyimide resin layer.

[0067] (Polyimide resin varnish) The polyimide resin varnish comprises the polyimide resin and a solvent. The polyimide resin contained in the polyimide resin varnish is the polyimide resin described in the section <Polyimide resin layer and polyimide resin>. A preferred method for producing the polyimide resin is described below.

[0068] (Method for producing polyimide resin) The polyimide resin may be produced by any method, but it is preferable to produce it by the method shown below. The method for producing the polyimide resin is to react a tetracarboxylic dianhydride with a diamine in the presence of a solvent to obtain a polyimide resin. In this specification, the tetracarboxylic dianhydride that is a raw material for the polyimide resin is also called the tetracarboxylic component, and the diamine is also called the diamine component. There are no particular restrictions on the method for polymerizing the tetracarboxylic dianhydride and the diamine, and known methods can be used. Specific reaction methods include (1) a method in which a solution containing the diamine and a solvent and the tetracarboxylic dianhydride are charged into a reactor, stirred at 10 to 110°C for 0.5 to 30 hours as needed, and then the temperature is raised to carry out the imidation reaction, and (2) a method in which a solution containing the diamine and a solvent and the tetracarboxylic dianhydride are charged into a reactor and the temperature is immediately raised to carry out the imidation reaction.

[0069] In the imidation reaction, it is preferable to carry out the reaction while removing the water generated during production using a Dean-Stark apparatus or similar device. By performing such an operation, the degree of polymerization and the imidation rate can be further increased.

[0070] In the above imidation reaction, known imidation catalysts can be used. Examples of imidation catalysts include base catalysts and acid catalysts. Examples of base catalysts include organic base catalysts such as pyridine, quinoline, isoquinoline, α-picoline, β-picoline, 2,4-lutidine, 2,6-lutidine, trimethylamine, triethylamine, tripropylamine, tributylamine, triethylenediamine, imidazole, N,N-dimethylaniline, and N,N-diethylaniline; and inorganic base catalysts such as potassium hydroxide, sodium hydroxide, potassium carbonate, sodium carbonate, potassium bicarbonate, and sodium bicarbonate. Examples of acid catalysts include crotonic acid, acrylic acid, trans-3-hexenoic acid, cinnamic acid, benzoic acid, methylbenzoic acid, oxybenzoic acid, terephthalic acid, benzenesulfonic acid, p-toluenesulfonic acid, and naphthalenesulfonic acid. The above imidation catalysts may be used individually or in combination of two or more types. Of the above, from the viewpoint of ease of handling, a base catalyst is preferred, an organic base catalyst is more preferred, one or more selected from the group consisting of triethylamine and triethylenediamine are even more preferred, triethylamine is even more preferred, and the combination of triethylamine and triethylenediamine is even more preferred.

[0071] The temperature of the imidation reaction is preferably 120 to 250°C, more preferably 160 to 200°C, from the viewpoint of the reaction rate and suppression of gelation, etc. The reaction time is preferably 0.5 to 10 hours after the start of distillation of the generated water. Furthermore, the amount of diamine relative to the amount of tetracarboxylic dianhydride is preferably 0.9 to 1.1 moles.

[0072] The concentration of polyimide in the resulting solution is preferably 1 to 50% by mass, more preferably 3 to 35% by mass, and even more preferably 5 to 30% by mass. Next, the raw materials used in the method for producing polyimide resin will be described.

[0073] [Tetracarboxylic acid dianhydride] The tetracarboxylic acid dianhydride used as a raw material in the above manufacturing method is preferably the tetracarboxylic acid dianhydride described in the constituent unit A of the polyimide resin. Examples of tetracarboxylic acid dianhydrides include acid dianhydrides, but are not limited to them; derivatives thereof may also be used as long as they give the constituent unit A. Examples of such derivatives include tetracarboxylic acid (free acid) and alkyl esters of the tetracarboxylic acid. Among these, acid dianhydrides are preferred.

[0074] [Diamine] The diamine used as a raw material in the above manufacturing method is preferably the diamine described in the constituent unit B of the polyimide resin. Examples of diamines include diamines, but are not limited to them; derivatives thereof may also be used as long as they provide constituent unit B in the polymer. Examples of such derivatives include diisocyanates corresponding to diamines. Among these, diamines are preferred.

[0075] [End-Sealing Agents] In addition to the tetracarboxylic dianhydride and diamine mentioned above, end-sealing agents may also be used in the production of polyimide resins. Acid anhydrides, monoamines, or dicarboxylic acids are preferred as end-sealing agents. The amount of end-sealing agent to be introduced is preferably 0.0001 to 20 moles, more preferably 0.1 to 10 moles, and even more preferably 0.5 to 5 moles per mole of tetracarboxylic dianhydride. Recommended monoamine end-sealing agents include, for example, methylamine, ethylamine, propylamine, butylamine, benzylamine, 4-methylbenzylamine, 4-ethylbenzylamine, 4-dodecylbenzylamine, 3-methylbenzylamine, 3-ethylbenzylamine, aniline, 3-methylaniline, 4-methylaniline, o-aminophenol, m-aminophenol, p-aminophenol, o-aminobenzoic acid, m-aminobenzoic acid, and p-aminobenzoic acid. Of these, benzylamine, aniline, o-aminophenol, m-aminophenol, p-aminophenol, o-aminobenzoic acid, m-aminobenzoic acid, and p-aminobenzoic acid can be suitably used. As dicarboxylic acid end-capping agents, dicarboxylic acids are preferred, and some of them may be ring-closed. For example, phthalic acid, phthalic anhydride, 4-chlorophthalic acid, tetrafluorophthalic acid, 2,3-benzophenone dicarboxylic acid, 3,4-benzophenone dicarboxylic acid, cyclopentane-1,2-dicarboxylic acid, 4-cyclohexene-1,2-dicarboxylic acid, trimellitic anhydride, etc. are recommended. Of these, phthalic acid, phthalic anhydride, and trimellitic anhydride can be suitably used.

[0076] [Solvent (Reaction Solvent)] The solvent (reaction solvent) used in the production of the polyimide resin may be any solvent capable of dissolving the resulting polyimide resin, but it is preferable to use the solvent contained in the varnish described below. Using the solvent contained in the varnish as the reaction solvent is convenient and preferable because it allows the polyimide resin solution itself after the production of the polyimide resin, or the polyimide resin varnish itself, to be used simply by adding the solvent to adjust the concentration.

[0077] Examples of solvents (reaction solvents) include phenolic solvents, etheric solvents, carbonate solvents, amide solvents, lactone solvents, phosphorus-containing amide solvents, sulfur-containing solvents, ketone solvents, and ester solvents, with amide solvents or lactone solvents being preferred, and lactone solvents being more preferred.

[0078] Examples of amide solvents include 1,3-dimethyl-2-imidazolidinone (DMI), 3-methyl-2-oxazolidone, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, tetramethylurea, 3-methoxy-N,N-dimethylpropanamide, 3-butoxy-N,N-dimethylpropanamide, and the like. Preferably, it is at least one selected from the group consisting of 1,3-dimethyl-2-imidazolidinone, 3-methyl-2-oxazolidone, 3-methoxy-N,N-dimethylpropanamide, 3-butoxy-N,N-dimethylpropanamide, and N-methyl-2-pyrrolidone. More preferably, it is at least one selected from the group consisting of 1,3-dimethyl-2-imidazolidinone and 3-methyl-2-oxazolidone, and even more preferably, it is 1,3-dimethyl-2-imidazolidinone.

[0079] Examples of lactone-based solvents include γ-butyrolactone and γ-valerolactone, with γ-butyrolactone being preferred. Examples of phosphorus-containing amide-based solvents include hexamethylphosphoric amide and hexamethylphosphinetriamide. Examples of sulfur-containing solvents include dimethyl sulfone, dimethyl sulfoxide, and sulfolane. Examples of ketone-based solvents include acetone, methyl ethyl ketone, cyclohexanone, methylcyclohexanone, and cyclopentanone. Examples of ester-based solvents include acetic acid (2-methoxy-1-methylethyl).

[0080] Examples of phenolic solvents include phenol, o-cresol, m-cresol, p-cresol, 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,4-xylenol, and 3,5-xylenol.

[0081] Examples of ether-based solvents include propylene glycol monomethyl ether (PGME), 1,2-dimethoxyethane, bis(2-methoxyethyl) ether, 1,2-bis(2-methoxyethoxy)ethane, bis[2-(2-methoxyethoxy)ethyl] ether, tetrahydrofuran, and 1,4-dioxane, with propylene glycol monomethyl ether (PGME) being preferred.

[0082] Examples of carbonate-based solvents include diethyl carbonate, methyl ethyl carbonate, ethylene carbonate, and propylene carbonate.

[0083] As described above, the solvent preferably contains at least one selected from the group consisting of 1,3-dimethyl-2-imidazolidinone (DMI), 3-methyl-2-oxazolidone, γ-butyrolactone (GBL), N-methylpyrrolidone (NMP), γ-valerolactone, 3-methoxy-N,N-dimethylpropanamide, propylene glycol monomethyl ether (PGME), cyclohexanone, and cyclopentanone; more preferably contains at least one selected from the group consisting of 1,3-dimethyl-2-imidazolidinone, 3-methyl-2-oxazolidone, and γ-butyrolactone; even more preferably contains at least one selected from the group consisting of 1,3-dimethyl-2-imidazolidinone and γ-butyrolactone; and even more preferably contains γ-butyrolactone. The above solvents may be used alone or in mixtures of two or more.

[0084] (Solvent) The polyimide resin varnish contains a solvent in addition to the polyimide resin described above. That is, the polyimide resin is preferably dissolved in the solvent. Examples of solvents contained in the polyimide resin varnish include phenolic solvents, etheric solvents, carbonate solvents, amide solvents, lactone solvents, phosphorus-containing amide solvents, sulfur-containing solvents, ketone solvents, and ester solvents, with amide solvents or lactone solvents being preferred, and lactone solvents being more preferred.

[0085] Examples of amide solvents include 1,3-dimethyl-2-imidazolidinone (DMI), 3-methyl-2-oxazolidone, N,N-dimethylformamide, N,N-dimethylacetamide, N-methyl-2-pyrrolidone, N-methylcaprolactam, tetramethylurea, 3-methoxy-N,N-dimethylpropanamide, 3-butoxy-N,N-dimethylpropanamide, and the like. Preferably, it is at least one selected from the group consisting of 1,3-dimethyl-2-imidazolidinone, 3-methyl-2-oxazolidone, 3-methoxy-N,N-dimethylpropanamide, 3-butoxy-N,N-dimethylpropanamide, and N-methyl-2-pyrrolidone. More preferably, it is at least one selected from the group consisting of 1,3-dimethyl-2-imidazolidinone and 3-methyl-2-oxazolidone, and even more preferably, it is 1,3-dimethyl-2-imidazolidinone.

[0086] Examples of lactone-based solvents include γ-butyrolactone and γ-valerolactone, with γ-butyrolactone being preferred. Examples of phosphorus-containing amide-based solvents include hexamethylphosphoric amide and hexamethylphosphinetriamide. Examples of sulfur-containing solvents include dimethyl sulfone, dimethyl sulfoxide, and sulfolane. Examples of ketone-based solvents include acetone, methyl ethyl ketone, cyclohexanone, methylcyclohexanone, and cyclopentanone. Examples of ester-based solvents include acetic acid (2-methoxy-1-methylethyl).

[0087] Examples of phenolic solvents include phenol, o-cresol, m-cresol, p-cresol, 2,3-xylenol, 2,4-xylenol, 2,5-xylenol, 2,6-xylenol, 3,4-xylenol, and 3,5-xylenol.

[0088] Examples of ether-based solvents include propylene glycol monomethyl ether (PGME), 1,2-dimethoxyethane, bis(2-methoxyethyl) ether, 1,2-bis(2-methoxyethoxy)ethane, bis[2-(2-methoxyethoxy)ethyl] ether, tetrahydrofuran, and 1,4-dioxane, with propylene glycol monomethyl ether (PGME) being preferred.

[0089] Examples of carbonate-based solvents include diethyl carbonate, methyl ethyl carbonate, ethylene carbonate, and propylene carbonate.

[0090] As described above, the solvent preferably contains at least one selected from the group consisting of 1,3-dimethyl-2-imidazolidinone (DMI), 3-methyl-2-oxazolidone, γ-butyrolactone (GBL), N-methylpyrrolidone (NMP), γ-valerolactone, and 3-methoxy-N,N-dimethylpropanamide, propylene glycol monomethyl ether (PGME), cyclohexanone, and cyclopentanone. More preferably, it contains at least one selected from the group consisting of 1,3-dimethyl-2-imidazolidinone, 3-methyl-2-oxazolidone, and γ-butyrolactone. Even more preferably, it contains at least one selected from the group consisting of 1,3-dimethyl-2-imidazolidinone and γ-butyrolactone, and even more preferably, it contains γ-butyrolactone. The above solvents may be used alone or in mixtures of two or more.

[0091] The varnish of the present invention may be the polyimide resin solution itself after the production of the polyimide resin, or it may be a solution of the polyimide resin solution that has been further diluted by mixing in a solvent.

[0092] (Other Components) In addition to the polyimide resin and solvent, the polyimide resin varnish of the present invention may contain other components, to the extent that they do not impair the required properties of the resulting polyimide film and varnish. Examples of other components include inorganic fillers, adhesion promoters, release agents, flame retardants, UV stabilizers, surfactants, leveling agents, defoamers, fluorescent whitening agents, crosslinking agents, polymerization initiators, and photosensitive agents.

[0093] Since the polyimide resin contained in the varnish of the present invention is solvent-soluble, a highly concentrated varnish that is stable at room temperature can be obtained. The varnish of the present invention preferably contains 3 to 40% by mass of polyimide resin, and more preferably 5 to 30% by mass. The viscosity of the varnish is preferably 0.1 to 100 Pa·s, and more preferably 0.1 to 20 Pa·s. The viscosity of the varnish is the value measured at 25°C using an E-type viscometer. The method for producing the varnish of the present invention is not particularly limited, and known methods can be applied. For example, it can be obtained by adjusting the concentration by mixing a solution of polyimide resin obtained by the above-described production method with an additional solvent as needed.

[0094] (Coating and Heating Method) In this process, the polyimide resin varnish is applied to the surface-modified substrate and heated to obtain a polyimide resin layer. There are no restrictions on the method of applying the polyimide resin varnish to the surface-modified substrate. Known coating methods include spin coating, slit coating, and blade coating. Among these, spin coating is preferred from the viewpoint of improving film uniformity and workability.

[0095] The heating temperature is preferably 300°C or higher, more preferably 300 to 500°C. The heating time is preferably 1 minute to 6 hours, more preferably 10 minutes to 3 hours, and even more preferably 20 minutes to 2 hours. In order to remove the solvent contained in the varnish, preheating may be performed at 60 to 250°C before heating to 300°C or higher. The preheating temperature is preferably 60 to 250°C, more preferably 70 to 180°C. The preheating time is preferably 1 minute to 6 hours, more preferably 5 minutes to 2 hours, and even more preferably 10 minutes to 1 hour. Preheating may be performed multiple times. Examples of heating atmospheres include air, nitrogen gas, oxygen gas, hydrogen gas, and nitrogen / hydrogen mixed gas. However, in order to suppress discoloration of the resulting polyimide resin, nitrogen gas with an oxygen concentration of 100 ppm or less and nitrogen / hydrogen mixed gas with a hydrogen concentration of 0.5% or less are preferred.

[0096] (Step of laminating an inorganic film) The laminate of the present invention has a polyimide resin layer on a substrate surface-modified with a compound having an oxysilyl group, but may further have an inorganic film made of silicon oxide or silicon nitride on the polyimide resin layer. When the laminate of the present invention has an inorganic film, preferably, after the step of obtaining the polyimide resin layer, there is a further step of laminating an inorganic film made of silicon oxide or silicon nitride on the polyimide resin layer. The inorganic film may be laminated by any method, but it is preferably laminated by sputtering, CVD deposition, or vacuum deposition.

[0097] The present invention will be specifically described below with reference to examples. However, the present invention is not limited in any way by these examples.

[0098] [Evaluation of Polyimide Resin Varnish and Polyimide Film (Polyimide Resin)] (1) Solubility of Varnish One volume of the varnish obtained in the production example and 99 volumes of cyclopentanone were mixed at 25°C to obtain a mixture. The state of the mixture was evaluated visually according to the following criteria. The results are shown in Table 1. (Evaluation Criteria) A: No precipitates were found, and it was uniformly dissolved. B: Precipitates (polyimide resin) were observed, and it was non-uniform.

[0099] (2) Thermal properties of the film (glass transition temperature (Tg)) The polyimide resin varnish obtained in the manufacturing example was applied to a substrate (4-inch silicon wafer), held at 100°C for 20 minutes on a hot plate, and then heated in a hot air dryer under a nitrogen atmosphere at a heating rate of 5°C / min to 400°C, and heated at 400°C for 120 minutes to evaporate the solvent and thermal imideize to obtain a polyimide film. The obtained polyimide film was subjected to TMA measurement using a thermomechanical analyzer "TMA 7100C" manufactured by Hitachi High-Tech Science Co., Ltd., with a sample size of 4 mm x 20 mm, in tensile mode, under conditions of a load of 50 mN and a heating rate of 10°C / min, and heated from 40°C to 500°C. The point where an inflection point was observed was extrapolated to determine the glass transition temperature (Tg). The higher the glass transition temperature (Tg) value, the better the heat resistance.

[0100] [Manufacturing of Polyimide Resin Varnish] The tetracarboxylic acid component, diamine component, solvent, imidation catalyst, and their abbreviations used in the manufacturing example are as follows. <Tetracarboxylic acid components> HPMDA: 1,2,4,5-cyclohexanetetracarboxylic dianhydride (manufactured by Mitsubishi Gas Chemical Co., Ltd., compound represented by formula (a3)) DNDA: (4arH,8acH)-decahydro-1t,4t:5c,8c-dimethanonaphthalene-2t,3t,6c,7c-tetracarboxylic dianhydride (manufactured by DAXIN; compound represented by formula (a5)) PMDA: pyromellitic anhydride (manufactured by Tokyo Chemical Industry Co., Ltd., compound represented by formula (a6)) <Diamine components> BAFL: 9,9-bis(4-aminophenyl)fluorene (manufactured by JFE Chemical Corporation) BODA: 4,4'-bis(4-aminophenoxy)biphenyl (manufactured by Seika Co., Ltd.) <Solvent> GBL: γ-butyrolactone (manufactured by Mitsubishi Chemical Corporation) <Imidation catalyst> TEA: triethylamine TEDA: Triethylenediamine

[0101] Preparation Example 1 A 500 mL five-necked round-bottom flask equipped with a stainless steel crescent-shaped stirring blade, nitrogen inlet tube, Dean-Stark condenser, thermometer, and glass end cap contained 34.845 g (0.100 mol) of BAFL and 85.075 g of GBL. The mixture was stirred at 200 rpm under a nitrogen atmosphere at a system temperature of 70°C to obtain a solution. To this solution, 22.417 g (0.100 mol) of HPMDA and 15.952 g of GBL were added all at once. Then, 0.506 g of TEA, 0.056 g of TEDA, and 5.317 g of GBL were added as imidation catalysts. The mixture was heated with a mantle heater, and the reaction system temperature was raised to 190°C over approximately 30 minutes. The components removed by distillation were collected, and the reaction system temperature was maintained at 190°C while adjusting the rotation speed in accordance with the increase in viscosity, and refluxed for 3 hours. Then, GBL was added to achieve a solid content concentration of 15% by mass, the reaction system temperature was cooled to 120°C, and the mixture was stirred for a further 1 hour to homogenize it, thereby obtaining polyimide resin varnish (PI-1).

[0102] Production Examples 2 and 3: A polyimide resin varnish with a solid content of 15% by mass was obtained in the same manner as in Production Example 1, except that the tetracarboxylic acid component and the diamine component were changed as shown in Table 1.

[0103]

[0104] [Evaluation of Laminates] (1) Adhesion The adhesion of the laminates obtained in the examples and comparative examples (laminated after pre-baking, laminated after post-baking, and laminated after storage at 85°C and 85% RH for 1008 hours) was measured according to ASTM D3359. Specifically, a cross-cut test was performed under the following conditions to evaluate the adhesion. Using a cutter guide and a cutter knife, 10 x 10 cuts (100 squares (1 mm x 1 mm square size)) were made in the polyimide resin layer of the laminate, reaching the silicon wafer layer. Cellophane adhesive tape (CT-24, Cellotape®, manufactured by Nichiban Co., Ltd.) was applied flat to the grid area (cross-cut area) by the cuts, extending 20 mm beyond the grid area, ensuring that no air bubbles were trapped. The applied tape was peeled off within 0.5 to 1 second, the state of the grid area was observed, and the number of squares that remained without peeling was counted. The more squares that remained, the higher the adhesion. The evaluation criteria for each laminate were as follows. Furthermore, the more the polyimide resin layer is not peeled off without post-baking and the more masses remain, the higher the adhesion. The overall evaluation criteria for each laminate were as follows. (Adhesion evaluation criteria) A: The number of remaining masses is 90 or more out of 100 masses B: The number of remaining masses is 80 or more out of 100 masses and 89 or less C: The number of remaining masses is 70 or more out of 100 masses and 79 or less D: The number of remaining masses is 69 or less out of 100 masses (Overall evaluation criteria) A: The adhesion evaluation of the laminate after pre-baking is A. B: The adhesion evaluation of the laminate after pre-baking is B or less, and the adhesion evaluation of the laminate after post-baking is A. C: The adhesion evaluation of the laminate after post-baking is C or B. D: The adhesion evaluation of the laminate after post-baking is D.

[0105] (2) Heat resistance (CVD resistance and annealing resistance) Laminates obtained in the examples and comparative examples (post-baked laminates; substrate / polyimide layer) were subjected to CVD deposition under the following conditions, and the presence or absence of cracks in the inorganic film of the laminate (substrate / polyimide layer / inorganic film) after CVD deposition was evaluated by visual inspection and microscopic observation (100x magnification) (CVD resistance). Next, the laminates after CVD deposition were subjected to annealing treatment at 350°C for 1 hour. The presence or absence of cracks in the inorganic film of the laminate (substrate / polyimide layer / inorganic film) after annealing treatment was evaluated by visual inspection and microscopic observation (100x magnification) (annealing resistance). In all cases, the smaller the size of the cracks, the fewer defects there were during film deposition, the better the heat resistance, and the better the result. Those without cracks had no defects during film deposition, had even better heat resistance, and were better. (Evaluation criteria) A: No cracks were observed in the inorganic film by visual inspection or microscopic observation (100x magnification). B: No cracks are visible in the inorganic film to the naked eye, but cracks are visible in the inorganic film when observed under a microscope (magnified 100 times). C: Cracks are visible in the inorganic film to the naked eye. (Inorganic film deposition conditions) ・Equipment: Plasma CVD system MPX-CVD (manufactured by Sumitomo Precision Products Co., Ltd.) ・Deposition method: PE-CVD ・Film thickness: 5,000 Å ・Upper electrode temperature: 250℃ ・Lower electrode temperature: 350℃ ・Deposition time: 41 minutes 15 seconds ・Plasma generation power supply frequency: 380 kHz (LF) ・RF output: 30 W ・Gas flow rate: SiH4 / NH3 / N2 = 10 / 10 / 2000 sccm

[0106] [Manufacturing of Laminate (Base Material / Polyimide Resin Layer)] The compounds having oxysilyl groups used in the examples and comparative examples, and their abbreviations, are as follows: <Compounds having oxysilyl groups> KBM-903: 3-aminopropyltrimethoxysilane (a compound having a primary amino group, manufactured by Shin-Etsu Chemical Co., Ltd.) KBE-903: 3-aminopropyltriethoxysilane (a compound having a primary amino group, manufactured by Shin-Etsu Chemical Co., Ltd.) VD-5: Trialkoxysilane having a melamine-like structure (a compound having a primary amino group, "VD-5", manufactured by Shikoku Chemicals, Inc.) KBM-573: N-phenyl-3-aminopropyltrimethoxysilane (a compound having a secondary amino group, without a primary amino group, manufactured by Shin-Etsu Chemical Co., Ltd.)

[0107] Example 1 (Laminate after pre-baking) KBM-903 was diluted to 0.1% by mass with isopropyl alcohol to obtain a solution of a compound having an oxysilyl group. The obtained solution was applied to a 4-inch silicon wafer by spin coating (1,500 rpm, 30 seconds), and then held on a hot plate at 100°C for 2 minutes to obtain a substrate surface-modified with the compound having an oxysilyl group. Subsequently, the polyimide resin varnish (PI-1) obtained in Production Example 1 was applied to the surface-modified substrate, and dried on a hot plate at 100°C for 20 minutes to obtain a laminate after pre-baking. The adhesion to the laminate after pre-baking was evaluated. The evaluation results are shown in Table 2.

[0108] (Laminate after post-baking) The pre-baked laminate was placed in a hot air dryer and heated to 400°C at a heating rate of 5°C / min under a nitrogen atmosphere in the hot air dryer. The laminate was then heated at 400°C for 120 minutes to evaporate the solvent and obtain a post-baked laminate. The adhesion and heat resistance of the post-baked laminate were evaluated. The evaluation results are shown in Table 2.

[0109] (Laminate after 1008 hours of storage at 85°C and 85% RH) The post-baked laminate was placed in a low-temperature constant-temperature and humidity chamber (ETAC HIFLEX NEO FX410N, manufactured by Kusumoto Kasei Co., Ltd.) and left to stand for 1008 hours in an environment of 85°C and 85% RH to obtain a laminate after 1008 hours of storage at 85°C and 85% RH. The adhesion of the laminate after 1008 hours of storage at 85°C and 85% RH was evaluated. The evaluation results are shown in Table 2.

[0110] Examples 2-8 and Comparative Examples 2-6 Laminates were obtained in the same manner as in Example 1, except that the type of compound having an oxysilyl group, the concentration of the compound solution having an oxysilyl group, and the type of polyimide resin varnish were changed as shown in Tables 2 and 3. VD-5 was diluted with propylene glycol monomethyl ether (PGME) to obtain a solution of the compound having an oxysilyl group. The evaluation results are shown in Tables 2 and 3.

[0111] Comparative Example 1: The substrate was not surface-modified with a compound containing an oxysilyl group. In other words, a laminate was obtained in the same manner as in Example 1, except that a 4-inch silicon wafer was used instead of the substrate surface-modified with a compound containing an oxysilyl group. The evaluation results are shown in Table 3.

[0112]

[0113]

[0114] As shown in Table 2, the laminate of the example exhibits excellent heat resistance and adhesion. In particular, its adhesion is significantly superior to that of the comparative example laminate shown in Table 3. Therefore, because the laminate of the present invention has excellent heat resistance and adhesion, it is useful as a laminate in semiconductor processes.

Claims

1. A laminate having a polyimide resin layer on a substrate surface-modified with a compound having an oxysilyl group, wherein the compound having an oxysilyl group is at least one selected from the group consisting of compounds having a succinic anhydride structure and compounds having a primary amino group, the polyimide resin constituting the polyimide resin layer has an alicyclic structure, and the glass transition temperature of the polyimide resin is 300°C or higher.

2. The laminate according to claim 1, further comprising an inorganic film made of silicon oxide or silicon nitride on the polyimide resin layer.

3. The laminate according to claim 2, wherein the thickness of the inorganic film is 1 to 1,000 nm.

4. The laminate according to any one of claims 1 to 3, wherein the polyimide resin has at least one selected from the group consisting of structural units of formula (3), formula (4), and formula (5).

5. The laminate according to claim 4, wherein the polyimide resin further comprises structural units of the following formula (6).

6. The laminate according to any one of claims 1 to 5, wherein the thickness of the polyimide resin layer is 0.5 to 300 μm.

7. The laminate according to any one of claims 1 to 6, wherein the substrate is silicon, silicon carbide, gallium nitride, gallium oxide, aluminum nitride, or diamond.

8. The laminate according to any one of claims 1 to 7, wherein the compound having an oxysilyl group is at least one selected from the group consisting of compounds represented by the following general formula (1), compounds represented by the following general formula (2), and compounds having a melamine-like structure and an oxysilyl group. (In formula (1), R 1 This is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a phenyl group, or an aminoalkyl group having 1 to 6 carbon atoms, and has three R 1 They may be different. In equation (2), R 2 This is a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a phenyl group, or an aminoalkyl group having 1 to 6 carbon atoms, and has three R 2 They may be different.

9. R 1 is a methyl group, R 2 The laminate according to claim 8, wherein is a methyl group or an ethyl group.

10. A method for producing a laminate, comprising the steps of: applying a solution containing a compound having an oxysilyl group and a solvent onto a substrate, firing it to obtain a substrate surface-modified with the compound having an oxysilyl group; and applying a polyimide resin varnish containing a polyimide resin and a solvent onto the surface-modified substrate, and heating it to obtain a polyimide resin layer, wherein the compound having an oxysilyl group is at least one selected from the group consisting of compounds having a succinic anhydride structure and compounds having a primary amino group, the polyimide resin has an alicyclic structure, and the glass transition temperature of the polyimide resin is 300°C or higher.

11. The method for producing a laminate according to claim 10, wherein the solvent contained in the polyimide resin varnish contains at least one selected from the group consisting of 1,3-dimethyl-2-imidazolidinone and γ-butyrolactone.

12. A method for manufacturing a laminate according to claim 10 or 11, further comprising the step of laminating an inorganic film made of silicon oxide or silicon nitride on the polyimide resin layer.

13. The method for manufacturing a laminate according to any one of claims 10 to 12, wherein the polyimide resin has at least one structural unit selected from the group consisting of the structural unit of formula (3), the structural unit of formula (4), and the structural unit of formula (5).

14. The method for manufacturing a laminate according to claim 13, wherein the polyimide resin further has a structural unit of the following formula (6).

15. The method for manufacturing a laminate according to any one of claims 10 to 14, wherein the substrate is silicon, silicon carbide, gallium nitride, gallium oxide, aluminum nitride, or diamond.

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