Laminate

Abstract

A laminate having a support substrate, a polyimide resin layer on the support substrate, and an inorganic film on the polyimide resin layer, the polyimide resin constituting the polyimide resin layer having a glass transition temperature of 300 DEG C or higher, and the inorganic film having a compressive stress; also provided is a method for producing a laminate, which comprises: a step in which a polyimide resin varnish or a polyimide resin precursor varnish is applied to a support substrate and heated to obtain a polyimide resin layer; and a step for forming an inorganic film having compressive stress on the polyimide resin layer.

Description

Technical Field

[0001] This invention relates to laminates and methods for manufacturing laminates. Background Technology

[0002] In the semiconductor field, with the advancement of 3D mounting technology, there is a growing demand for materials that can withstand processes such as TSV formation, back-side wiring, CVD, and hybrid bonding.

[0003] Polyimide resin has long been known for its excellent mechanical properties, heat resistance, and insulation. As a result, it has been studied for various applications in electrical / electronic components and has also been used as an insulating film.

[0004] On the other hand, resin materials such as polyimide are rarely used alone due to concerns about degassing caused by moisture absorption and decomposition. Inorganic films such as SiO and SiN are used as buffer layers and barrier layers.

[0005] For example, in Patent Document 1, for the purpose of improving colorless transparency, low residual stress, mechanical properties, thermal properties, and bending resistance, a polyimide film, a laminate having a polyimide film and a support, and a flexible substrate having a polyimide film and an inorganic film are disclosed. The polyimide film is formed by imidizing bis(trifluoromethyl)benzidine and a polyimide precursor having siloxane structural units, has a glass transition temperature of 150 to 380°C, and has an imide group concentration of 2.00 to 3.70 mmol / g.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: International Publication No. 2014 / 098235 Summary of the Invention

[0009] The problem the invention aims to solve

[0010] In the semiconductor field, inorganic films are laminated onto resin materials such as polyimide, as described above, and therefore, high film-forming properties are required for these laminates. Especially in CVD and hybrid bonding (Cu-Cu bonding), even higher heat resistance above 300°C is required.

[0011] In processes where a temperature higher than the inorganic film formation temperature is applied after inorganic film formation, even highly heat-resistant polyimides can sometimes experience defects such as cracking and peeling.

[0012] Therefore, there is a need for laminates composed of polyimide resin, inorganic film and supporting substrate that are suitable for high-temperature processes.

[0013] The present invention was made in view of the following situation, and the object of the present invention is to provide a laminate with excellent film-forming properties and, consequently, excellent heat resistance.

[0014] Solution for solving the problem

[0015] The inventors discovered that the above-mentioned problems can be solved by a laminate having a polyimide resin layer with a glass transition temperature of 300°C or higher on a supporting substrate, and further having an inorganic film with compressive stress, thereby completing the invention.

[0016] That is, the present invention relates to the following [1] to [8].

[0017] [1] A laminate comprising: a support substrate, a polyimide resin layer on the support substrate, and an inorganic film on the polyimide resin layer, wherein the glass transition temperature of the polyimide resin constituting the polyimide resin layer is 300°C or higher, and the stress of the inorganic film is compressive stress.

[0018] [2] According to the laminate described in [1] above, wherein the aforementioned inorganic film comprises silicon.

[0019] [3] According to the laminate described in [1] or [2] above, wherein the inorganic film is silicon oxide or silicon nitride.

[0020] [4] The laminate according to any one of [1] to [3] above, wherein the film thickness of the aforementioned polyimide resin layer is 0.5 to 300 μm.

[0021] [5] The laminate according to any one of [1] to [4] above, wherein the thickness of the aforementioned inorganic film is 1 to 1000 nm.

[0022] [6] The laminate according to any one of [1] to [5] above, wherein the aforementioned support substrate comprises silicon.

[0023] [7] The laminate according to any one of [1] to [6] above, wherein the aforementioned support substrate is silicon, silicon carbide, gallium nitride, gallium oxide, aluminum nitride or diamond.

[0024] [8] A method for manufacturing a laminate includes a step of coating a support substrate with a polyimide resin varnish or a polyimide resin precursor varnish and heating it to obtain a polyimide resin layer, and a step of forming an inorganic film with compressive stress on the aforementioned polyimide resin layer.

[0025] The effects of the invention

[0026] According to the present invention, a laminate with excellent film-forming properties and, consequently, excellent heat resistance can be provided. The laminate of the present invention has the properties described above, and is therefore useful as a laminate in semiconductor processes. That is, the laminate of the present invention is useful as a laminate for semiconductor memories, LSI stacks, CMOS image sensors, MEMS packaging, optical devices, LED applications, and the like. Detailed Implementation

[0027] [Layered Body]

[0028] The laminate of the present invention is a laminate comprising: a supporting substrate, a polyimide resin layer on the supporting substrate, and an inorganic film on the polyimide resin layer, wherein the glass transition temperature of the polyimide resin constituting the polyimide resin layer is 300°C or higher, and the stress of the inorganic film is compressive stress.

[0029] <Supporting Substrate>

[0030] The laminate of the present invention has a supporting substrate.

[0031] The aforementioned support substrate is preferably silicon, silicon carbide, gallium nitride, gallium oxide, aluminum nitride, or diamond, and more preferably silicon.

[0032] By using silicon as the aforementioned support substrate, the film-forming properties and heat resistance, particularly as an effect of the laminate of the present invention, are excellent. Furthermore, silicon is excellent as a support substrate in the present invention because of its excellent yield during crystal formation and the availability of raw materials.

[0033] The thickness of the aforementioned support substrate is preferably 1 μm to 1 mm, more preferably 2 μm to 900 μm, even more preferably 10 to 800 μm, and even more preferably 100 to 700 μm. When multiple support substrates are used, the above thickness refers to the thickness of each individual support substrate; the thicknesses of the multiple support substrates can be the same or different.

[0034] There are no particular limitations on the shape of the aforementioned support substrate. For example, if the aforementioned support substrate is a silicon substrate, it can be a silicon substrate with an interlayer insulating layer (Low-k film) formed on it.

[0035] Examples of interlayer insulating layers include silicon oxide films and silicon nitride films, with silicon nitride films being the preferred choice.

[0036] <Polyimide resin layer and polyimide resin>

[0037] The laminate of the present invention has a polyimide resin layer on the aforementioned support substrate.

[0038] The glass transition temperature of the polyimide resin constituting the aforementioned polyimide resin layer is above 300°C.

[0039] The thickness of the aforementioned polyimide resin layer is preferably 0.5 to 300 μm, more preferably 1 to 100 μm, even more preferably 1 to 50 μm, even more preferably 1 to 30 μm, and even more preferably 5 to 20 μm.

[0040] The glass transition temperature of the aforementioned polyimide resin is 300°C or higher. Preferably, the glass transition temperature of the aforementioned polyimide resin is 350°C or higher, more preferably 380°C or higher, even more preferably 400°C or higher, even more preferably 420°C or higher, even more preferably 430°C or higher, and even more preferably 440°C or higher. There is no upper limit, but it is preferably 550°C or lower. By setting the glass transition temperature of the aforementioned polyimide resin to the above range, the laminate of the present invention exhibits excellent heat resistance and is useful as a laminate in semiconductor processes.

[0041] The structure of the polyimide resin constituting the aforementioned polyimide resin layer is not limited as long as its glass transition temperature is above 300°C. The aforementioned polyimide resin preferably has the structural unit of the following general formula (1).

[0042]

[0043] The aforementioned polyimide resin preferably has a structural unit of formula (1), more preferably has at least one structural unit selected from the group consisting of structural units of formula (1a) and structural units of formula (1b), and even more preferably has a structural unit of formula (1b).

[0044]

[0045] The polyimide resin having the structural unit of formula (1a) is further preferably composed of at least one of the repeating units selected from the group consisting of repeating units shown in formula (2a) and repeating units shown in formula (3a), and even more preferably composed of repeating units shown in formula (2a), and even more preferably composed of repeating units shown in formula (2a) and repeating units shown in formula (3a).

[0046]

[0047] It should be noted that the "repeating unit" in polyimide resin refers to an imide unit containing one structural unit derived from tetracarboxylic dianhydride and one structural unit derived from diamine.

[0048] The ratio of the repeating unit shown in formula (2a) to the total of the repeating units shown in formula (2a) and formula (3a) is preferably 30 to 100 mol%. From the viewpoint of transparency, it is more preferably 40 to 100 mol%, even more preferably 50 to 100 mol%, and still more preferably 60 to 100 mol%, even more preferably 70 to 100 mol%, even more preferably 80 to 100 mol%, and still more preferably 90 to 100 mol%, or it can be 100 mol%. In addition, from the viewpoint of heat resistance and strength, it is more preferably 30 to 90 mol%, even more preferably 30 to 80 mol%, even more preferably 30 to 70 mol%, even more preferably 30 to 60 mol%, and still more preferably 30 to 50 mol%.

[0049] From the viewpoint of heat resistance and mechanical strength, the total of the repeating units shown in formula (2a) and formula (3a) is preferably 50 mol% or more and 100 mol% or less relative to all the repeating units of the aforementioned polyimide resin, more preferably 70 mol% or more and 100 mol% or less. Further 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 can be 100 mol%, which is even more preferably 100 mol% from the viewpoint of heat resistance and mechanical strength.

[0050] From the viewpoint of transparency, the repeating unit shown in formula (2a) 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, and even more preferably 90 mol% or more, relative to all the repeating units of the aforementioned polyimide resin. The upper limit is 100 mol% or less.

[0051] Polyimide resins may also contain repeating units other than those shown in formula (2a) and general formula (3a).

[0052] The content of repeating units other than those shown in formula (2a) and general formula (3a) is preferably 50 mol% or less, more preferably 30 mol% or less, even more preferably 20 mol% or less, even more preferably 10 mol% or less, even more preferably 5 mol% or less, even more preferably 1 mol% or less, even more preferably 0 mol%, and even more preferably not included, relative to all repeating units of the aforementioned polyimide resin.

[0053] The aforementioned polyimide resin having the structural unit of formula (1b) further preferably includes the repeating unit shown in formula (2b) below.

[0054]

[0055] From the viewpoint of heat resistance and mechanical strength, the repeating unit shown in formula (2b) is preferably 50 mol% or more and 100 mol% or less relative to all repeating units of the aforementioned polyimide resin, more preferably 70 mol% or more and 100 mol% or less. Further 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 can be 100 mol%, which is even more preferably 100 mol% from the viewpoint of heat resistance and adhesion.

[0056] Polyimide resins may also contain repeating units other than those shown in formula (2b).

[0057] The content of repeating units other than the repeating unit shown in formula (2b) is preferably 50 mol% or less, more preferably 30 mol% or less, even more preferably 20 mol% or less, even more preferably 10 mol% or less, even more preferably 5 mol% or less, even more preferably 1 mol% or less, even more preferably 0 mol%, and even more preferably not included, relative to all repeating units of the aforementioned polyimide resin.

[0058] As described above, the aforementioned polyimide resin is further preferably composed of at least one of the repeating units selected from the group consisting of repeating units shown in formula (2a), repeating units shown in formula (3a), and repeating units shown in formula (2b), and is even more preferably composed of repeating units shown in formula (2b). By including the repeating units shown in formula (2b), it is soluble in all solvents during the preparation of varnishes, and is particularly soluble in ester-based solvents, therefore it is preferred.

[0059] <Structural Units of Polyimide Resin>

[0060] The aforementioned polyimide resin has structural unit A derived from tetracarboxylic dianhydride and structural unit B derived from diamine.

[0061] It should be noted that in polyimide resin, structural unit A and structural unit B form an imide structure.

[0062] Structural unit A preferably comprises at least one selected from the group consisting of structural units (A1) derived from compounds represented by formula (a1), structural units (A2) derived from compounds represented by formula (a2), and structural units (A3) derived from compounds represented by formula (a3). Structural unit B preferably comprises at least one selected from the group consisting of structural units (B1) derived from compounds represented by formula (b1), structural units (B2) derived from compounds represented by formula (b2), and structural units (B3) derived from compounds represented by formula (b3).

[0063]

[0064] (Structural Unit A)

[0065] Structural unit A is a structural unit derived from tetracarboxylic dianhydride, preferably comprising at least one selected from the group consisting of structural units (A1) derived from the compound represented by formula (a1), structural units (A2) derived from the compound represented by formula (a2), and structural units (A3) derived from the compound represented by formula (a3), more preferably comprising structural units (A3) derived from the compound represented by formula (a3). In the case of comprising structural units (A1) derived from the compound represented by formula (a1), it is even more preferable to comprise structural units (A1) derived from the compound represented by formula (a1) and structural units (A2) derived from the compound represented by formula (a2).

[0066] The compound represented by formula (a1) is 4,4'-oxophthalic anhydride (ODPA). By using the structural unit (A1) derived from the compound represented by formula (a1) as the structural unit of the polyimide resin, the polyimide resin exhibits excellent heat resistance and strength.

[0067] The compound represented by formula (a2) is 3,3',4,4'-biphenyltetracarboxylic acid dianhydride (s-BPDA). By using the structural unit (A2) derived from the compound represented by formula (a2) as the structural unit of the polyimide resin, it is possible to further improve the heat resistance and strength.

[0068] The compound represented by formula (a3) ​​is 3,3',4,4'-diphenylsulfone tetracarboxylic dianhydride (DSDA). By using the structural unit (A3) derived from the compound represented by formula (a3) ​​as the structural unit of the polyimide resin, heat resistance and adhesion can be further improved.

[0069] The total ratio of structural unit (A1), structural unit (A2), and structural unit (A3) in structural unit A is preferably 50 mol% or more and 100 mol% or less. More preferably, it is 70 mol% or more and 100 mol% or less, even more preferably, it is 80 mol% or more and 100 mol% or less, even more preferably, it is 90 mol% or more and 100 mol% or less, even more preferably, it is 95 mol% or more and 100 mol% or less, even more preferably, it is 99 mol% or more and 100 mol% or less, and it can be 100 mol%, which is even more preferably 100 mol% from the viewpoint of heat resistance and mechanical strength.

[0070] When structural unit A includes structural unit (A1) and structural unit (A2), the total ratio of structural unit (A1) and structural unit (A2) in structural unit A is preferably 50 mol% or more and 100 mol% or less, more preferably 70 mol% or more and 100 mol% or less. Further 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. From the viewpoint of heat resistance and mechanical strength, 100 mol% is even more preferred.

[0071] The ratio of structural unit (A1) to the total of structural units (A1) and (A2) is preferably 30 to 100 mol%. From the viewpoint of heat resistance, strength, and transparency, it is more preferably 40 to 100 mol%, even more preferably 50 to 100 mol%, and still more preferably 60 to 100 mol%, even more preferably 70 to 100 mol%, even more preferably 80 to 100 mol%, and still more preferably 90 to 100 mol%, and may also be 100 mol%. Furthermore, from the viewpoint of heat resistance and strength, it is more preferably 30 to 90 mol%, even more preferably 30 to 80 mol%, even more preferably 30 to 70 mol%, even more preferably 30 to 60 mol%, and still more preferably 30 to 50 mol%.

[0072] From the viewpoints of heat resistance, strength, and transparency, the ratio of structural units (A1) in structural 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, and even more preferably 90 mol% or more. The upper limit is 100 mol% or less.

[0073] When structural unit A includes structural unit (A3), the ratio of structural unit (A3) in structural unit A is preferably 50 mol% or more and 100 mol% or less. More preferably, it is 70 mol% or more and 100 mol% or less, even more preferably 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 from the viewpoint of heat resistance and sealing, it is even more preferably 100 mol%.

[0074] Structural unit A may also include structural units other than structural units (A1), (A2), and (A3). There are no particular limitations on such structural units; examples include structural units derived from aromatic tetracarboxylic dianhydrides, alicyclic tetracarboxylic dianhydrides, and aliphatic tetracarboxylic dianhydrides, excluding structural units (A1), (A2), and (A3).

[0075] Examples of aromatic tetracarboxylic dianhydrides that provide structural units derived from aromatic tetracarboxylic dianhydrides, other than structural units (A1), (A2), and (A3), include pyromellitic tetracarboxylic anhydride (PMDA), 3,3',4,4'-benzophenone tetracarboxylic dianhydride (BTDA), 9,9-bis(trifluoromethyl)-9H-xanthon-2,3,6,7-tetracarboxylic dianhydride (6FCDA), and 2,2-bis[4] [-(3,4-dicarboxyphenoxy)phenyl]hexafluoropropane dianhydride, 2,3,3',4'-biphenyltetracarboxylic acid dianhydride (a-BPDA), 9,9'-bis(3,4-dicarboxyphenyl)fluorene dianhydride (BPAF), hydroquinone diphthalic anhydride (HQDEA), ethylene glycol bis(triptyl phthalate) dianhydride (TMEG), p-phenylene bis(triptyl phthalate) dianhydride (TAHQ), 4,4'-(hexafluoroisopropylidene)di... Phthalic anhydride (6FDA), 2,2',3,3',5,5'-hexamethyl[1,1'-biphenyl]-4,4'-diyl-bis(1,3-dioxo-1,3-dihydro-2-benzofuran-5-carboxylate) (TMPBP-TME), 2,2-bis(3,4-dicarboxyphenyl)-propane dianhydride, spiro[11H-difurano[3,4-b:3',4'-i]xanthon-11,9'-[ [9H]fluorene]-1,3,7,9-tetraone (SFDA), 4,4'-thiodiphthalic anhydride, 5-[4-(1,3-dioxo-2-benzofuran-5-yl)phenyl]-2-benzofuran-1,3-dione, 5-[3-(1,3-dioxo-2-benzofuran-5-yl)phenyl]-2-benzofuran-1,3-dione, p-Biphenylbis(trimethicone monoester anhydride) (BP-TME).

[0076] Among them, pyromellitic phthalic anhydride (PMDA) is preferred. By giving structural unit A a structural unit derived from PMDA, a laminate with good sealing, high-density packing, flatness, and heat resistance can be obtained.

[0077] Examples of alicyclic tetracarboxylic dianhydrides that provide structural units derived from alicyclic tetracarboxylic dianhydrides include cyclohexane-1,2,4,5-tetracarboxylic dianhydrides (HPMDA), cyclohexane-1,2,3,4-tetracarboxylic dianhydrides, 1,2,3,4-cyclobutanetetracarboxylic dianhydrides, 1,2,3,4-cyclopentanetetracarboxylic dianhydrides, 1,2,4,5-cyclopentanetetracarboxylic dianhydrides, 3,3',4,4'-biscyclohexyltetracarboxylic dianhydrides, 1,2,3,4-tetramethyl-1,2,3,4-cyclobutanetetracarboxylic dianhydrides, decahydro-1,4:5,8-dimethylnaphthalene-2,3,6,7-tetracarboxylic dianhydrides (DNDA), and 5,5'-(1,4-phenylene)-bis[hexahydro-4,7-bridged methyleneisobenzofuran-1,3-dione](5,5'-(1,4-phenylene)-bis[h [exahydro-4,7-Methanoisobenzofuran-1,3-dione]), 5,5'-bis-2-norbornen-5,5',6,6'-tetracarboxylic acid-5,5',6,6'-dianhydride, norbornan-2-spiro-α-cyclopentanone-α'-spiro-2”-norbornan-5,5',6,6'-tetracarboxylic anhydride (CpODA), 2,2 -Propylene-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, oxo-4,4'-bis(cyclohexane-1,2-dicarboxylic acid) dianhydride, bicyclo[2.2.2]oct-7-ene-2,3,5,6-tetracarboxylic acid dianhydride, bicyclo[2.2.2]octane-2,3:5,6-tetracarboxylic acid dianhydride (BODA), bicyclo[4.4.0]decane-2,3,6,7-tetracarboxylic acid dianhydride, etc.

[0078] Examples of aliphatic tetracarboxylic dianhydrides that provide structural units derived from aliphatic tetracarboxylic dianhydrides include 1,2,3,4-butanetetracarboxylic dianhydrides.

[0079] Structural unit A may contain one type of structural unit or two or more types of structural units.

[0080] It should be noted that, in this specification, aromatic tetracarboxylic dianhydride refers to tetracarboxylic dianhydride containing one or more aromatic rings, alicyclic tetracarboxylic dianhydride refers to tetracarboxylic dianhydride containing one or more alicyclic rings but without aromatic rings, and aliphatic tetracarboxylic dianhydride refers to tetracarboxylic dianhydride containing neither aromatic rings nor alicyclic rings.

[0081] (Structural Unit B)

[0082] Structural unit B is a structural unit derived from diamine, preferably comprising at least one of the structural units (B1) derived from the compound represented by formula (b1), structural units (B2) derived from the compound represented by formula (b2), and structural units (B3) derived from the compound represented by formula (b3), more preferably comprising at least one of the structural units (B1) derived from the compound represented by formula (b1) and structural units (B2) derived from the compound represented by formula (b2), and even more preferably comprising structural unit (B1) derived from the compound represented by formula (b1).

[0083] The compound shown in formula (b1) is 4-aminophenyl-4-aminobenzoate (4-BAAB). By incorporating structural unit (B1) into structural unit B, the resulting polyimide resin exhibits excellent heat resistance and improved adhesion.

[0084] The compound shown in formula (b2) is bis(4-aminophenyl) terephthalate (APTP). By incorporating structural unit (B2) into structural unit B, the resulting polyimide resin exhibits excellent heat resistance, thereby also improving the adhesion of the polyimide resin.

[0085] The compound shown in formula (b3) is 1,4-bis(4-aminobenzoyloxy)benzene. By incorporating structural unit (B3) into structural unit B, the resulting polyimide resin exhibits excellent heat resistance, thereby also improving the adhesion of the polyimide resin.

[0086] The total ratio of structural unit (B1), structural unit (B2), and structural unit (B3) in structural unit B is preferably 30 to 100 mol%, more preferably 70 to 100 mol%, even more preferably 90 to 100 mol%, and still more preferably 95 to 100 mol%, or 100 mol%. Structural unit B may be composed of at least one of the groups selected from structural unit (B1), structural unit (B2), and structural unit (B3).

[0087] The ratio of structural unit (B1) in structural unit B is preferably 30 to 100 mol%, more preferably 70 to 100 mol%, even more preferably 90 to 100 mol%, and even more preferably 95 to 100 mol%, and can be 100 mol%. Structural unit B may consist of only structural unit (B1).

[0088] The ratio of structural unit (B2) in structural unit B is preferably 30 to 100 mol%, more preferably 70 to 100 mol%, even more preferably 90 to 100 mol%, and even more preferably 95 to 100 mol%, and can be 100 mol%. Structural unit B may consist of only structural unit (B2).

[0089] The ratio of structural unit (B3) in structural unit B is preferably 30 to 100 mol%, more preferably 70 to 100 mol%, even more preferably 90 to 100 mol%, and even more preferably 95 to 100 mol%, and can be 100 mol%. Structural unit B may consist of only structural unit (B3).

[0090] By setting the ratio of structural unit (B1), structural unit (B2), and structural unit (B3) within the above range, the obtained polyimide resin exhibits excellent heat resistance, thereby also improving the coatability of the varnish and the adhesion of the polyimide resin.

[0091] Structural unit B may also include structural units other than structural units (B1), (B2), and (B3). There are no particular limitations on the diamines that provide such structural units; examples include aromatic diamines, alicyclic diamines, and aliphatic diamines, excluding those shown in formula (b1), formula (b2), and formula (b3).

[0092] Examples of aromatic diamines include 2,2'-bis(trifluoromethyl)-4,4'-diaminodiphenyl ether (6FODA), 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl (2,2'-TFMB), 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), and 3,4'-diaminodiphenyl ether (6FODA). Diphenyl 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), 9,9-bis(4-aminophenyl)fluorene (BAFL), 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)-indene Indane (5-TMDM), 6-amino-1,3,3-trimethyl-1-(4-aminophenyl)-indane (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, 4,4'-bis(4-aminophenoxy)biphenyl (BODA), 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]one, bis[4-(4-aminophenoxy)phenyl]one, 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-diaminobenzoylaniline, 4-aminobenzoic acid-4-aminophenyl ester, 3,4-diaminobenzoylaniline, etc.

[0093] Examples of alicyclic diamines include 1,3-bis(aminomethyl)cyclohexane (1,3-BAC), 1,4-bis(aminomethyl)cyclohexane, 1,3-cyclohexyldiamine, 1,4-cyclohexyldiamine, isophorone diamine, bis(aminomethyl)norbornene, 4,4'-diaminodicyclohexylmethane, 4,4'-diaminodicyclohexyl ether, and 2,2-bis(4-aminocyclohexyl)propane.

[0094] Examples of aliphatic diamines include ethylenediamine and hexamethylenediamine.

[0095] It should be noted that, in this specification, aromatic diamines refer to diamines containing one or more aromatic rings, alicyclic diamines refer to diamines containing one or more alicyclic rings but without aromatic rings, and aliphatic diamines refer to diamines containing neither aromatic rings nor alicyclic rings.

[0096] Structural unit B may contain one or more structural units other than structural units (B1), (B2), and (B3).

[0097] The aforementioned polyimide resin may include structures other than polyimide chains (structures formed by imide bonding of structural unit A and structural unit B) without impairing the scope of this invention. Examples of structures other than polyimide chains that may be included in the polyimide resin include, for example, structures containing amide bonds.

[0098] The aforementioned polyimide resin preferably comprises a polyimide chain (a structure formed by the bonding of structural unit A and structural unit B with imide) as its main structure. Therefore, the proportion of the polyimide chain in the aforementioned 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.

[0099] <Manufacturing Method of Polyimide Resin>

[0100] The aforementioned polyimide resin can be manufactured by any method, but is preferably manufactured by the method shown below.

[0101] The aforementioned polyimide resin can be obtained directly by polymerizing a diamine (hereinafter also referred to as the diamine component) with a tetracarboxylic dianhydride (hereinafter also referred to as the tetracarboxylic acid component), or by polymerizing a diamine with a tetracarboxylic dianhydride to obtain a polyamic acid or an imide-amic acid copolymer as a precursor of the polyimide resin (polyimide resin precursor). Imidization is then performed during the manufacture of the laminate to obtain the polyimide resin. Preferably, the imidization is performed when the polyimide resin precursor is obtained to manufacture the laminate.

[0102] Here, we will describe the imide-amic acid copolymer as a precursor of polyimide resin, the method for manufacturing polyamic acid, and the method for manufacturing polyimide resin directly to obtain polyimide resin. It should be noted that the polyimide resin precursor and polyimide resin are sometimes collectively referred to as polymers.

[0103] (Method for manufacturing imide-amic acid copolymers as precursors to polyimide resins)

[0104] A preferred manufacturing method for a polymer comprising both imide units and ammonium acid units (hereinafter also referred to as an imide-ammonium acid copolymer) includes steps 1 and 2 described below.

[0105] Step 1: The process of reacting tetracarboxylic acid dianhydride with diamine in the presence of a solvent to obtain imide oligomers;

[0106] Step 2: A step of mixing and polymerizing the imide oligomer obtained in Step 1 with at least one of tetracarboxylic dianhydride and diamine.

[0107] [Process 1]

[0108] Step 1 is a process of reacting a tetracarboxylic dianhydride with a diamine in the presence of a solvent to obtain an imide oligomer. The aforementioned tetracarboxylic dianhydride and diamine constitute the imide moiety.

[0109] In step 1, the diamine relative to the tetracarboxylic acid dianhydride is preferably 1.01 to 2 moles, more preferably 1.05 to 1.9 moles, and even more preferably 1.1 to 1.7 moles.

[0110] There are no particular restrictions on the method used in step 1 to react tetracarboxylic acid dianhydride with diamine to obtain imide oligomers; known methods can be used.

[0111] Specific reaction methods include the following: (1) adding tetracarboxylic acid dianhydride, diamine and solvent into a reactor, stirring at 10-110°C for 0.5-30 hours, and then raising the temperature to carry out the imidization reaction; (2) adding diamine and solvent into a reactor and dissolving them, then adding tetracarboxylic acid dianhydride, stirring at 10-110°C for 0.5-30 hours as needed, and then raising the temperature to carry out the imidization reaction; (3) adding tetracarboxylic acid dianhydride, diamine and solvent into a reactor, and immediately raising the temperature to carry out the imidization reaction, etc.

[0112] In the imidization reaction, it is preferable to use a Dean-Stark apparatus or similar device to carry out the reaction while removing water generated during manufacturing. By performing this operation, the degree of polymerization and the imidization rate can be further improved.

[0113] In the above imidization reaction, known imidization catalysts can be used. Examples of imidization catalysts include base catalysts and acid catalysts.

[0114] Examples of organic base catalysts include pyridine, quinoline, isoquinoline, α-methylpyridine, β-methylpyridine, 2,4-dimethylpyridine, 2,6-dimethylpyridine, trimethylamine, triethylamine, tripropylamine, tributylamine, triethylenediamine, imidazole, N,N-dimethylaniline, and N,N-diethylaniline; and inorganic base catalysts include potassium hydroxide, sodium hydroxide, potassium carbonate, sodium carbonate, potassium bicarbonate, and sodium bicarbonate.

[0115] In addition, examples of acid catalysts include crotonic acid, acrylic acid, trans-3-hexenoic acid, cinnamic acid, benzoic acid, methylbenzoic acid, hydroxybenzoic acid, terephthalic acid, benzenesulfonic acid, p-toluenesulfonic acid, and naphthalenesulfonic acid. These imidization catalysts can be used alone or in combination of two or more.

[0116] From an operational point of view, a base catalyst is preferred, an organic base catalyst is more preferred, one or more selected from triethylamine and triethylenediamine are even more preferred, and triethylamine is even more preferred.

[0117] From the viewpoints of reaction rate and inhibition of gelation, the temperature for the imidization reaction is preferably 120–250°C, more preferably 160–200°C. Furthermore, the reaction time is preferably 0.5–10 hours after the distillation of water begins.

[0118] The above method can yield a solution containing imide oligomers dissolved in a solvent. In the solution containing imide oligomers obtained in step 1, at least a portion of the components used in step 1 as tetracarboxylic dianhydride and diamine may be present in the form of unreacted monomers, without impairing the effects of the present invention.

[0119] [Process 2]

[0120] Step 2 is a process of mixing and polymerizing the imide oligomer obtained in step 1 with at least one of tetracarboxylic dianhydride and diamine.

[0121] Preferably, the diamine component in both steps 1 and 2 is set to 0.9 to 1.1 moles relative to the tetracarboxylic acid component.

[0122] In step 2, there are no particular restrictions on the method for polymerizing the imide oligomer, tetracarboxylic dianhydride, and diamine obtained in step 1, and known methods can be used.

[0123] Specific reaction methods include the following: (1) adding an imide oligomer and at least one of a tetracarboxylic dianhydride and a diamine into a reactor and stirring for 1 to 72 hours at a temperature of 0 to 120°C, preferably 5 to 80°C; (2) adding an imide oligomer and a solvent into a reactor to dissolve them, then adding at least one of a tetracarboxylic dianhydride and a diamine and stirring for 1 to 72 hours at a temperature of 0 to 120°C, preferably 5 to 80°C.

[0124] When the reaction is carried out at a temperature below 80°C, the molecular weight of the copolymer obtained in step 2 does not change depending on the temperature history of polymerization, and the thermal imidization process can also be suppressed, thus enabling the stable production of the copolymer.

[0125] The concentration of the copolymer 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.

[0126] (Method for manufacturing polyamic acid as a precursor to polyimide resin)

[0127] When the polyimide resin precursor is polyamic acid, the preferred method for producing the polyimide resin precursor is to react a tetracarboxylic dianhydride with a diamine in the presence of a solvent to obtain polyamic acid.

[0128] There are no particular restrictions on the method for polymerizing tetracarboxylic dianhydride with diamine; known methods can be used.

[0129] Specific reaction methods include the following: adding a solution containing a diamine and a solvent, along with a tetracarboxylic acid dianhydride, into a reactor, preferably stirring at 0–120°C, more preferably at 5–80°C, for 1–72 hours.

[0130] The diamine component is preferably 0.9 to 1.1 moles relative to the tetracarboxylic acid component.

[0131] When the reaction is carried out at temperatures below 80°C, the molecular weight of the polyamic acid does not change depending on the temperature of the polymerization process, and the thermal imidization process can also be suppressed, thus enabling the stable production of the polyamic acid.

[0132] The concentration of polyamic acid in the obtained solution is preferably 1 to 50% by mass, more preferably 3 to 35% by mass, and even more preferably 5 to 30% by mass.

[0133] (Manufacturing method of polyimide resin)

[0134] A preferred method for directly obtaining polyimide resin is to react tetracarboxylic acid dianhydride with diamine in the presence of a solvent to obtain polyimide resin.

[0135] There are no particular restrictions on the method for polymerizing tetracarboxylic dianhydride with diamine; known methods can be used.

[0136] As specific reaction methods, the following methods can be listed: (1) a method in which a solution containing diamine and solvent and tetracarboxylic acid dianhydride are added to a reactor, stirred at 10 to 110°C for 0.5 to 30 hours as needed, and then heated to carry out an imidization reaction; (2) a method in which a solution containing diamine and solvent and tetracarboxylic acid dianhydride are added to a reactor, and the temperature is immediately raised to carry out an imidization reaction, etc.

[0137] In the imidization reaction, it is preferable to use a Dean-Stark apparatus or similar device to carry out the reaction while removing water generated during manufacturing. By performing this operation, the degree of polymerization and the imidization rate can be further improved.

[0138] In the above imidization reaction, known imidization catalysts can be used. Examples of imidization catalysts include base catalysts and acid catalysts.

[0139] Examples of organic base catalysts include pyridine, quinoline, isoquinoline, α-methylpyridine, β-methylpyridine, 2,4-dimethylpyridine, 2,6-dimethylpyridine, trimethylamine, triethylamine, tripropylamine, tributylamine, triethylenediamine, imidazole, N,N-dimethylaniline, and N,N-diethylaniline; and inorganic base catalysts include potassium hydroxide, sodium hydroxide, potassium carbonate, sodium carbonate, potassium bicarbonate, and sodium bicarbonate.

[0140] In addition, examples of acid catalysts include crotonic acid, acrylic acid, trans-3-hexenoic acid, cinnamic acid, benzoic acid, methylbenzoic acid, hydroxybenzoic acid, terephthalic acid, benzenesulfonic acid, p-toluenesulfonic acid, and naphthalenesulfonic acid. These imidization catalysts can be used alone or in combination of two or more.

[0141] From an operational point of view, a base catalyst is preferred, an organic base catalyst is more preferred, one or more selected from triethylamine and triethylenediamine are even more preferred, and triethylamine is even more preferred.

[0142] From the viewpoints of reaction rate and inhibition of gelation, the temperature for the imidization reaction is preferably 120–250°C, more preferably 160–200°C. Furthermore, the reaction time is preferably 0.5–10 hours after the distillation of water begins.

[0143] 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.

[0144] Next, the raw materials used in the manufacturing methods of the aforementioned imide-amic acid copolymer, polyamic acid, and polyimide resin will be described.

[0145] [Tetracarboxylic acid dianhydride]

[0146] The tetracarboxylic dianhydride used as a raw material in the aforementioned manufacturing method is preferably the tetracarboxylic dianhydride described in structural unit A of the aforementioned polyimide resin.

[0147] Examples of tetracarboxylic acid dianhydrides include acid dianhydrides, but the invention is not limited to these; any derivative thereof may be used to provide the scope of the aforementioned structural unit A. Examples of such derivatives include tetracarboxylic acids (free acids) and alkyl esters of the tetracarboxylic acid. Among these, acid dianhydrides are preferred.

[0148] [Diamine]

[0149] The diamine used as a raw material in the aforementioned manufacturing method is preferably the diamine described in structural unit B of the aforementioned polyimide resin.

[0150] Examples of diamines include, but are not limited to, any diamine that provides structural unit B in the aforementioned polymer, and its derivatives may also be used. Examples of such derivatives include diisocyanates corresponding to diamines. Diamines are preferred.

[0151] [End-capping agent]

[0152] In addition to the aforementioned tetracarboxylic acid and diamine components, end-capping agents can also be used in the manufacturing of the polymer. The end-capping agent is preferably used in step 2 of the manufacturing of the aforementioned imide-amic acid copolymer.

[0153] As capping agents, anhydrides, monoamines, or dicarboxylic acids are preferred. The amount of capping agent introduced is preferably 0.0001 to 20 moles relative to 1 mole of the tetracarboxylic acid component, more preferably 0.1 to 10 moles, and even more preferably 0.5 to 5 moles. Examples of monoamine capping agents include 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. Benzylamine, aniline, o-aminophenol, m-aminophenol, p-aminophenol, o-aminobenzoic acid, m-aminobenzoic acid, and p-aminobenzoic acid are preferred. As dicarboxylic acid capping agents, dicarboxylic acids are preferred, and a portion of them may form a closed ring. 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, and trimellitic anhydride can be recommended. Among these, phthalic acid, phthalic anhydride, and trimellitic anhydride are preferred.

[0154] [Solvent]

[0155] The solvent used in polymer manufacturing methods can be any solvent capable of dissolving the resulting polymer. Examples include aprotic solvents, phenolic solvents, ether solvents, and carbonate solvents.

[0156] Specific examples of aprotic solvents include amide solvents that are cyclic amides or chain amides, phosphorus-containing amide solvents, sulfur-containing solvents, ketone solvents, and ester solvents that contain cyclic esters.

[0157] The solvent preferably comprises at least one selected from the group consisting of cyclic amides, chain amides and cyclic esters, and more preferably comprises cyclic amides.

[0158] Examples of cyclic amides include N-methylpyrrolidone, N-methylcaprolactam, and 1,3-dimethylimidazolium ketone, with N-methylpyrrolidone being preferred.

[0159] Examples of chain amides include N,N-dimethylformamide, N,N-dimethylacetamide, and tetramethylurea.

[0160] Examples of cyclic esters include γ-butyrolactone and γ-valerolactone.

[0161] Other ester solvents include acetic acid (2-methoxy-1-methylethyl) ester.

[0162] Examples of phosphorus-containing amide solvents include hexamethylphosphoramide and hexamethylphosphine triamide.

[0163] Examples of sulfur-containing solvents include dimethyl sulfone, dimethyl sulfoxide, and sulfolane.

[0164] Examples of ketone solvents include acetone, methyl ethyl ketone, cyclohexanone, and methyl cyclohexanone.

[0165] Specific 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.

[0166] Specific examples of ether-based solvents include 1,2-dimethoxyethane, bis(2-methoxyethyl) ether, 1,2-bis(2-methoxyethoxy)ethane, bis[2-(2-methoxyethoxy)ethyl] ether, tetrahydrofuran, and 1,4-dioxane.

[0167] Specific examples of carbonate-based solvents include diethyl carbonate, methyl ethyl carbonate, ethylene carbonate, and propylene carbonate.

[0168] The solvents described above preferably contain at least one selected from the group consisting of cyclic amides, chain amides, and cyclic esters; more preferably, they contain at least one selected from the group consisting of cyclic amides and cyclic esters; and even more preferably, they contain cyclic esters. More specifically, they contain at least one selected from the group consisting of N-methylpyrrolidone and γ-butyrolactone; and even more preferably, they contain γ-butyrolactone. The solvents described above can be used alone or in mixtures of two or more.

[0169] (Polyimide resin precursor)

[0170] In the aforementioned method for manufacturing polyimide resin and the method for manufacturing laminate described later, as mentioned above, the structure of the polyimide resin precursor used as the raw material for the aforementioned polyimide resin is not limited as long as the glass transition temperature of the obtained polyimide resin is 300°C or higher, and preferably has a structural unit of the following general formula (1).

[0171]

[0172] The aforementioned polyimide resin precursor preferably has a structural unit of formula (1), more preferably has at least one structural unit selected from the group consisting of structural units of formula (1a) and structural units of formula (1b), and even more preferably has a structural unit of formula (1b).

[0173]

[0174] The polyimide resin precursor having the structural unit of formula (1a) is further preferably composed of at least one of the repeating units selected from the group consisting of repeating units shown in formula (4a) and repeating units shown in formula (5a), and even more preferably composed of repeating units shown in formula (4a), and even more preferably composed of repeating units shown in formula (4a) and repeating units shown in formula (5a).

[0175]

[0176] (In equations (4a) and (5a), X) 1 and X 2 Each is independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkylsilyl group having 3 to 9 carbon atoms.

[0177] It should be noted that the "repeating unit" in the polyimide resin precursor refers to an amide acid unit containing a structural unit derived from tetracarboxylic dianhydride and a structural unit derived from diamine.

[0178] In the aforementioned equations (4a) and (5a), X 1 and X 2 Each of the following is independently selected from at least one of the group consisting of hydrogen atoms, alkyl groups having 1 to 6 carbon atoms, and alkylsilyl groups having 3 to 9 carbon atoms, preferably at least one of the group consisting of hydrogen atoms and alkyl groups having 1 to 6 carbon atoms, and more preferably hydrogen atoms.

[0179] The ratio of the repeating unit shown in formula (4a) to the total of the repeating units shown in formula (4a) and formula (5a) is preferably 30 to 100 mol%. From the viewpoint of transparency, it is more preferably 40 to 100 mol%, even more preferably 50 to 100 mol%, and even more preferably 60 to 100 mol%, even more preferably 70 to 100 mol%, even more preferably 80 to 100 mol%, and even more preferably 90 to 100 mol%, or it can be 100 mol%. In addition, from the viewpoint of heat resistance and strength, it is more preferably 30 to 90 mol%, even more preferably 30 to 80 mol%, even more preferably 30 to 70 mol%, even more preferably 30 to 60 mol%, and even more preferably 30 to 50 mol%.

[0180] From the viewpoint of heat resistance and mechanical strength, the total amount of the repeating units shown in formula (4a) and formula (5a) relative to all the repeating units of the aforementioned polyimide resin precursor is preferably 50 mol% or more and 100 mol% or less, more preferably 70 mol% or more and 100 mol% or less. Further 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 can be 100 mol%, which is even more preferably 100 mol% from the viewpoint of heat resistance and mechanical strength.

[0181] From the viewpoint of transparency, the repeating unit shown in formula (4a) 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, and even more preferably 90 mol% or more, relative to all the repeating units of the aforementioned polyimide resin precursor. The upper limit is 100 mol% or less.

[0182] The polyimide resin precursor may also contain repeating units other than those shown in formula (4a) and general formula (5a).

[0183] The content of repeating units other than those shown in formula (4a) and general formula (5a) relative to all repeating units of the aforementioned polyimide resin precursor is preferably 50 mol% or less, more preferably 30 mol% or less, even more preferably 20 mol% or less, even more preferably 10 mol% or less, even more preferably 5 mol% or less, even more preferably 1 mol% or less, even more preferably 0 mol%, and even more preferably not included.

[0184] The aforementioned polyimide resin precursor having the structural unit of formula (1b) preferably contains repeating units as shown in formula (4b).

[0185]

[0186] (In equation (4b), X) 1 and X 2 Each is independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkylsilyl group having 3 to 9 carbon atoms.

[0187] In the aforementioned equation (4b), X 1 and X 2Each of the terms independently represents at least one selected from the group consisting of hydrogen atoms, alkyl groups having 1 to 6 carbon atoms, or alkylsilyl groups having 3 to 9 carbon atoms, preferably at least one selected from the group consisting of hydrogen atoms and alkyl groups having 1 to 6 carbon atoms, more preferably hydrogen atoms.

[0188] From the viewpoint of heat resistance and mechanical strength, the repeating unit shown in formula (4b) is preferably 50 mol% or more and 100 mol% or less relative to all repeating units of the aforementioned polyimide resin precursor, more preferably 70 mol% or more and 100 mol% or less. Further 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 can be 100 mol%, which is even more preferably 100 mol% from the viewpoint of heat resistance and adhesion.

[0189] The polyimide resin precursor may also contain repeating units other than those shown in formula (4b).

[0190] The content of repeating units other than the repeating unit shown in formula (4b) is preferably 50 mol% or less, more preferably 30 mol% or less, even more preferably 20 mol% or less, even more preferably 10 mol% or less, even more preferably 5 mol% or less, even more preferably 1 mol% or less, even more preferably 0 mol%, and even more preferably not included, relative to all repeating units of the aforementioned polyimide resin precursor.

[0191] As described above, the aforementioned polyimide resin precursor is further preferably composed of at least one of the repeating units selected from the group consisting of repeating units shown in formula (4a), repeating units shown in formula (5a), and repeating units shown in formula (4b), and is even more preferably composed of repeating units shown in formula (4b). By including the repeating units shown in formula (4b), it is soluble in all solvents during the preparation of varnishes, and is particularly soluble in ester-based solvents, therefore it is preferred.

[0192] It should be noted that when the aforementioned polyimide resin precursor is an imide-amic acid copolymer, it is preferable that it includes the repeating unit described in this section and the repeating unit described in the section on polyimide resin. Specifically, as the imide portion, it is preferable that it includes at least one of the repeating units selected from the group consisting of the repeating unit shown in formula (2b), the repeating unit shown in formula (2a), and the repeating unit shown in formula (3a), more preferably that it includes at least one of the group consisting of the repeating unit shown in formula (2b) and the repeating unit shown in formula (2a) below, and even more preferably that it includes the repeating unit shown in formula (2b). Moreover, as the amic acid portion, it is preferable that it includes at least one of the group consisting of the repeating unit shown in formula (4b), the repeating unit shown in formula (4a), and the repeating unit shown in formula (5a), more preferably that it includes at least one of the group consisting of the repeating unit shown in formula (4b) and the repeating unit shown in formula (4a) below, and even more preferably that it includes the repeating unit shown in formula (4b).

[0193] Varnish

[0194] The laminate of the present invention is preferably obtained by the following manufacturing method of the laminate, which includes a step of coating a support substrate with a polyimide resin varnish or a polyimide resin precursor varnish and heating it to obtain a polyimide resin layer; and further includes a step of forming an inorganic film with compressive stress on the aforementioned polyimide resin layer.

[0195] The following describes the varnish used in the manufacture of the laminate. However, the preferred varnishes are the same for both the varnish containing the polyimide resin constituting the polyimide resin layer and the organic solvent, and the varnish containing the precursor of the polyimide resin constituting the polyimide resin layer and the organic solvent. Therefore, they will be referred to as "varnish" in the following description.

[0196] The varnish contains the aforementioned polyimide resin and organic solvent, or contains a polyimide resin precursor and organic solvent.

[0197] The solvent can be any solvent that dissolves the polyimide resin or polyimide resin precursor, and there is no particular limitation. As the solvent used in the manufacture of the polyimide resin or polyimide resin precursor, it is preferable to use the above-mentioned compounds alone or in combination of two or more. The solvent preferably contains at least one selected from the group consisting of cyclic amides, chain amides, and cyclic esters, more preferably contains cyclic amides, and even more preferably contains N-methylpyrrolidone.

[0198] The varnish can be a polyimide resin solution or polyimide resin precursor solution obtained by the above-mentioned manufacturing method of polyimide resin or polyimide resin precursor, or it can be a varnish with further added solvent, or it can be a varnish with reduced solvent by concentration or the like.

[0199] In the case of a varnish containing a polyimide resin precursor, from the viewpoint of efficiently performing imidization of the amyl acid portion, the varnish may further contain an imidization catalyst and a dehydration catalyst. As an imidization catalyst, any imidization catalyst with a boiling point of 40°C or higher and 180°C or lower is acceptable; amine compounds with a boiling point of 180°C or lower are preferred catalysts. If an imidization catalyst with a boiling point of 180°C or lower is used, the polyimide film obtained after forming the laminate will not be discolored during high-temperature drying, and there is no concern about damage to the appearance. Furthermore, if an imidization catalyst with a boiling point of 40°C or higher is used, the possibility of volatilization before sufficient imidization is achieved can be avoided.

[0200] Pyridine or methylpyridine are examples of amine compounds suitable for use as imidization catalysts. These imidization catalysts can be used alone or in combination of two or more.

[0201] Examples of dehydration catalysts include acetic anhydride, propionic anhydride, n-butyric anhydride, benzoic anhydride, trifluoroacetic anhydride, and other acid anhydrides; carbodiimide compounds such as dicyclohexylcarbodiimide; etc. They can be used alone or in combination of two or more.

[0202] The polyimide resin or polyimide resin precursor contained in the varnish is solvent-soluble, thus allowing for the production of high-concentration varnishes. The varnish preferably contains 1 to 40% by mass of polyimide resin or polyimide resin precursor, more preferably 3 to 40% by mass, and even more preferably 5 to 30% by mass. The viscosity of the varnish is preferably 0.1 to 200 Pa·s, more preferably 1 to 20 Pa·s. The viscosity of the varnish is a value obtained by measuring it using an E-type viscometer at 25°C.

[0203] In addition, varnishes can contain various additives such as inorganic fillers, adhesion promoters, release agents, flame retardants, UV stabilizers, surfactants, leveling agents, defoamers, fluorescent whitening agents, crosslinking agents, polymerization initiators, and photosensitizers, within a range that does not impair the desired properties of the polyimide film.

[0204] Inorganic membranes

[0205] The laminate of the present invention is a laminate having a supporting substrate, a polyimide resin layer on the supporting substrate, and an inorganic film on the polyimide resin layer, wherein the stress of the inorganic film is compressive stress.

[0206] The stress in the aforementioned inorganic membrane is compressive stress.

[0207] The stress of the inorganic membrane is compressive stress, meaning that the stress S of the inorganic membrane calculated by the following Stony formula is negative. It should be noted that the laminate shown below represents a laminate in which a supporting substrate, a polyimide resin layer, and an inorganic membrane are stacked sequentially; the pre-laminated laminate represents a laminate in which a supporting substrate, a polyimide resin layer, and an inorganic membrane are stacked sequentially, but before the inorganic membrane is stacked.

[0208] [Mathematical Expression 1]

[0209]

[0210] (In the formula, S is the stress (average value) of the inorganic membrane (Pa),)

[0211] E / (1-ν) is the biaxial elastic modulus (Pa) of the pre-laminated matrix (supporting substrate / polyimide resin layer).

[0212] h is the thickness (m) of the pre-laminated structure (supporting substrate / polyimide resin layer).

[0213] t is the thickness (m) of the inorganic membrane.

[0214] R1 is the radius of curvature of the pre-laminated structure (supporting substrate / polyimide resin layer) at 25°C, and R2 is the radius of curvature of the laminate (supporting substrate / polyimide resin layer / inorganic film) at 25°C.

[0215] Specifically, the stress of the inorganic membrane can be calculated using the method described in the examples.

[0216] Typically, polyimides have a positive coefficient of linear expansion, thus the polyimide resin layer exhibits positive stress. The polyimide resin layer of the laminate of the present invention exhibits excellent heat resistance due to its structure comprising dianhydrides derived from specific acids and specific diamines, resulting in excellent film-forming properties of the inorganic film. Furthermore, by forming an inorganic film with compressive stress, the overall stress of the laminate is mitigated, thus the laminate of the present invention exhibits excellent annealing resistance, i.e., heat resistance, making it useful as a laminate in semiconductor processes.

[0217] The aforementioned inorganic film preferably contains silicon. More preferably, the aforementioned inorganic film contains at least one selected from the group consisting of silicon oxide and silicon nitride, and even more preferably, it contains silicon nitride. More preferably, the aforementioned inorganic film is composed of at least one selected from the group consisting of silicon oxide and silicon nitride, and the aforementioned inorganic film is further preferably silicon oxide or silicon nitride, and even more preferably silicon nitride. By using silicon nitride as the aforementioned inorganic film, the effects of the present invention can be fully utilized, exhibiting excellent film-forming properties and heat resistance. Furthermore, silicon nitride also has excellent barrier properties and chemical stability, therefore, it is an excellent inorganic film used in the laminate of the present invention.

[0218] The aforementioned inorganic membrane is an insulating membrane. That is, the aforementioned inorganic membrane functions as an insulating membrane in the laminate, as a barrier membrane, and also as a buffer membrane.

[0219] The thickness of the aforementioned inorganic film is preferably 1–1000 nm, more preferably 1–400 nm, even more preferably 10–300 nm, even more preferably 20–200 nm, and even more preferably 50–150 nm. By making the thickness of the aforementioned inorganic film within the above range, the effects of the present invention can be fully utilized, resulting in excellent film-forming properties and heat resistance.

[0220] [Manufacturing method of laminated bodies]

[0221] The laminate of the present invention can be obtained by any manufacturing method as long as it has the aforementioned structure, but is preferably manufactured by the following method.

[0222] Specifically, it is preferred to manufacture the laminate by a manufacturing method comprising the steps of coating a support substrate with a polyimide resin varnish or a polyimide resin precursor varnish and heating it to obtain a polyimide resin layer; and further comprising the step of forming an inorganic film with compressive stress on the aforementioned polyimide resin layer.

[0223] The supporting substrate, polyimide resin varnish, polyimide resin precursor varnish, polyimide resin, polyimide resin precursor, and inorganic film in this manufacturing method are as described above in this specification, and their preferred ranges are also as described above in this specification.

[0224] (The process of obtaining the polyimide resin layer)

[0225] In this manufacturing method, firstly, there is a step of coating a support substrate with a polyimide resin varnish or a polyimide resin precursor varnish and heating it to obtain a polyimide resin layer.

[0226] This process yields a pre-laminated body with a polyimide resin layer stacked on a supporting substrate. In the next process, the pre-laminated body forms an inorganic film, becoming the laminate of this invention.

[0227] The heating temperature is preferably 300°C or higher, more preferably 300-500°C. The heating time is typically 1 minute to 6 hours, preferably 10 minutes to 3 hours, and more preferably 20 minutes to 2 hours.

[0228] It should be noted that, in order to remove the solvent contained in the varnish, preheating can be performed at 60–250°C before heating to above 300°C. The preheating temperature is preferably 60–250°C, more preferably 70–180°C. Furthermore, 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 can be performed multiple times.

[0229] Examples of heating atmospheres include air, nitrogen, oxygen, hydrogen, and nitrogen / hydrogen mixtures. To suppress coloring of the resulting polyimide resin, nitrogen with an oxygen concentration of 100 ppm or less, or a nitrogen / hydrogen mixture containing a hydrogen concentration of 0.5% or less, is preferred.

[0230] (The process of forming an inorganic membrane)

[0231] The laminate of the present invention has a polyimide resin layer on a supporting substrate, and an inorganic film on the aforementioned polyimide resin layer, wherein the stress of the inorganic film is compressive stress.

[0232] In this process, an inorganic film with compressive stress is formed on the polyimide resin layer of the pre-laminated body obtained in the previous process.

[0233] Inorganic films can be formed by any method, preferably by sputtering, CVD, or vacuum evaporation. That is, the preferred method for forming inorganic films is sputtering, CVD, or vacuum evaporation, more preferably sputtering or CVD, and even more preferably CVD. Plasma CVD is even more preferred.

[0234] The preferred film formation conditions for plasma CVD film formation used to form inorganic films with compressive stress are as follows.

[0235] The plasma generation power frequency can be any frequency used in a typical plasma processing device, and can be adjusted appropriately according to other conditions. 380 kHz is preferred, 380 kHz and 13.56 MHz are more preferred to be used together, and 380 kHz and 13.56 MHz are even more preferred to be used alternately.

[0236] The RF power is preferably 20-60W, more preferably 20-50W, and even more preferably 20-40W.

[0237] The film-forming temperature is preferably 200–400°C, and more preferably 200–360°C.

[0238] The film-forming time can be appropriately selected according to the type of raw material of the inorganic membrane and the required membrane thickness, preferably 1 to 20 minutes, and more preferably 3 to 15 minutes.

[0239] The resulting laminate exhibits excellent film-forming properties and, consequently, excellent heat resistance, making it useful as a laminate in semiconductor processes. Specifically, the resulting laminate is useful for applications such as semiconductor memories, LSI stacks, CMOS image sensors, MEMS packaging, optical devices, and LEDs.

[0240] Example

[0241] The present invention will now be specifically described through examples. However, the present invention is not limited to these examples.

[0242] <Physical Properties of Polyimide Resins>

[0243] (1) Glass transition temperature of polyimide resin

[0244] The glass transition temperature of the polyimide resin constituting the polyimide resin layer in the laminates of the examples and comparative examples was determined as follows.

[0245] The polyamic acid varnish obtained in the examples and comparative examples (manufacturing of polyamic acid varnish) was coated on a support substrate (4-inch silicon wafer), held at 100°C for 10 minutes on a hot plate, and then heated to 400°C in a hot air dryer under a nitrogen atmosphere at a heating rate of 5°C / min. The temperature was then increased to 400°C for 30 minutes to evaporate the solvent and perform thermal imidization to obtain a polyimide film (10 μm thick).

[0246] For the obtained polyimide film, a thermomechanical analysis apparatus "TMA 7100C" manufactured by Hitachi High-Tech Science Corporation was used. The sample size was 4 mm × 20 mm, in tensile mode, with a load of 50 mN and a heating rate of 10 °C / min. The temperature was increased from 40 °C to 500 °C, and the location of the observed inflection point of elongation was extrapolated to the glass transition temperature (Tg). A higher glass transition temperature (Tg) indicates better heat resistance.

[0247] The glass transition temperatures of polyimide resins are shown in Table 1.

[0248] <Physical Properties of Inorganic Membranes>

[0249] (1) Stress in inorganic membranes

[0250] The radius of curvature R1 of the pre-laminated bodies (support substrate / polyimide resin layer) obtained in each example and comparative example (pre-laminated body manufacturing) at 25°C was measured using a residual stress measuring device "FLX-2320-S" (manufactured by KLA-Tencor).

[0251] Next, as described below, an inorganic film (silicon nitride film) is formed on the polyimide resin layer of the aforementioned pre-laminated body (supporting substrate / polyimide resin layer) under the conditions of each embodiment and comparative example, to obtain a laminate (supporting substrate / polyimide resin layer / inorganic film).

[0252] Then, using a residual stress measuring device "FLX-2320-S" (manufactured by KLA-Tencor), the radius of curvature R2 of the obtained laminate (supporting substrate / polyimide resin layer / inorganic film) at 25°C was measured.

[0253] Using R1 and R2 obtained above, the stress S of the inorganic membrane is calculated using the following Stony formula. Stress S is the stress generated between the pre-laminated material and the inorganic membrane. A positive value of stress S represents tensile stress, and a negative value represents compressive stress.

[0254] [Mathematical Expression 2]

[0255]

[0256] (in the formula,

[0257] S represents the stress (average value) of the inorganic membrane (Pa).

[0258] E / (1-ν) is the biaxial elastic modulus (Pa) of the pre-laminated material.

[0259] h is the thickness (m) of the pre-laminated body.

[0260] t represents the thickness (m) of the inorganic membrane.

[0261] Additionally, as mentioned above, R1 is the radius of curvature of the pre-laminated structure (supporting substrate / polyimide resin layer) at 25°C, and R2 is the radius of curvature of the laminate (supporting substrate / polyimide resin layer / inorganic film) at 25°C.

[0262] It should be noted that, in this embodiment, since the influence of the polyimide layer is minimal, the biaxial elastic modulus of the pre-laminated material is approximately the same as that of the supporting substrate.

[0263] <Process Evaluation>

[0264] The process evaluation of laminates is carried out using the methods shown below.

[0265] (1) Film-forming properties of inorganic films (evaluation of film-forming properties)

[0266] The inorganic film of the laminates (supporting substrate / polyimide resin layer / inorganic film) obtained in the examples and comparative examples was visually evaluated for cracks. Evaluation was not performed using a microscope; however, in cases where no cracks were found, further evaluation was conducted using a microscope (100x magnification). Smaller crack sizes indicated no adverse effects during film formation and higher heat resistance, which was considered good. The absence of cracks indicated no adverse effects during film formation and even higher heat resistance, which was also considered good.

[0267] A: Even when magnified to 100x using a microscope, no cracks were observed in the inorganic film.

[0268] C: No cracks were observed in the inorganic film by visual inspection, but cracks were observed in the inorganic film when magnified 100 times with a microscope.

[0269] D: Cracks in the inorganic membrane were observed visually.

[0270] (2) Annealing resistance (evaluation of heat resistance)

[0271] The laminates (supporting substrate / polyimide resin layer / inorganic film) obtained in the examples and comparative examples were heated and annealed at 400°C for 1 hour.

[0272] The inorganic film of the annealed laminate (supporting substrate / polyimide resin / inorganic film) was visually evaluated for cracks. Evaluation was performed using both visual inspection and microscopy. In cases where no cracks were found during initial evaluation without microscopy, further evaluation was conducted using a microscope (100x magnification). Smaller crack sizes generally indicate no adverse effects during film formation and higher heat resistance, which is considered good. The absence of cracks indicates no adverse effects during film formation and even higher heat resistance, which is also considered good.

[0273] A: Even when magnified to 100x using a microscope, no cracks were observed in the inorganic film.

[0274] C: No cracks were observed in the inorganic film by visual inspection, but cracks were observed in the inorganic film when magnified 100 times with a microscope.

[0275] D: Cracks in the inorganic membrane were observed visually.

[0276] The tetracarboxylic acid and diamine components used in the examples and comparative examples, as well as their abbreviations, are described below.

[0277] <Tetracarboxylic acid component>

[0278] ODPA: 4,4'-oxophthalic anhydride (manufactured by MANAC Corporation, compound shown in formula (a1))

[0279] s-BPDA: 3,3',4,4'-Biphenyltetracarboxylic acid dianhydride (manufactured by Mitsubishi Chemical Corporation, compound shown in formula (a2))

[0280] DSDA: 3,3',4,4'-Diphenylsulfone tetracarboxylic dianhydride (prepared by ChinaTech Chemical (Tianjin) Co., Ltd., compound shown in formula (a3))

[0281] PMDA: Pyromellitic anhydride (manufactured by Tokyo Chemical Industry Co., Ltd.)

[0282] <Diamine component>

[0283] 4-BAAB: 4-Aminophenyl-4-aminobenzoic acid ester (manufactured by Nippon Junryu Pharmaceutical Co., Ltd., compound shown in formula (b1))

[0284] APTP: Bis(4-aminophenyl) terephthalate (manufactured by Tokyo Chemical Industry Co., Ltd., compound shown in formula (b2))

[0285] The abbreviations for solvents and catalysts used in the examples and comparative examples are described below.

[0286] NMP: N-methyl-2-pyrrolidone (manufactured by Tokyo Pure Pharmaceutical Co., Ltd.)

[0287] GBL: γ-Butyrolactone (manufactured by Mitsubishi Chemical Corporation)

[0288] Manufacturing of Laminates (Supporting Substrate / Polyimide Resin Layer / Inorganic Film)

[0289] Example 1

[0290] (Manufacturing of polyamic acid varnish)

[0291] 34.836 g (0.100 mol) of APTP and 294.927 g of NMP were added to a 1 L five-necked round-bottom flask equipped with a stainless steel crescent-shaped stirring blade, a nitrogen inlet tube, a Dean-Stark condenser with a condenser, a thermometer, and glass end caps. The mixture was stirred at 200 rpm under a nitrogen atmosphere at a temperature of 50 °C to obtain a solution.

[0292] 15.511 g (0.050 mol) of ODPA, 14.711 g (0.050 mol) of s-BPDA and 73.732 g of NMP were added to the solution and stirred for 3 hours at 50°C using a covered resistance heater. Then, 108.429 g of NMP was added to obtain a polyamic acid varnish with a solid content of 12% by mass.

[0293] (Pre-laminated body manufacturing)

[0294] Next, the obtained polyamic acid varnish was coated onto a support substrate (4-inch silicon wafer, 525 μm ± 25 μm thick) and held at 80°C for 20 minutes on a hot plate. Then, the temperature was increased to 400°C in a hot air dryer under a nitrogen atmosphere at a heating rate of 5°C / min. Heating at 400°C for 60 minutes allowed the solvent to evaporate, resulting in thermal imidization and the formation of a polyimide resin layer (10 μm thick) on the support substrate, yielding a pre-laminated composite (support substrate / polyimide resin layer). It should be noted that the aforementioned "radius of curvature R1" was measured here.

[0295] (Manufacturing of laminates)

[0296] Next, an inorganic film (silicon nitride film) was formed on the polyimide resin layer of the pre-laminated body (supporting substrate / polyimide resin layer) under the following conditions to obtain a laminate (supporting substrate / polyimide resin layer / inorganic film). The evaluation results of the obtained laminate are shown in Table 1.

[0297] (Conditions for Inorganic Membrane Formation)

[0298] • Apparatus: MPX-CVD plasma CVD system (manufactured by Sumitomo Precision Industries, Ltd.)

[0299] Film formation method: PE-CVD

[0300] ·Film thickness: 1000Å

[0301] • Upper electrode temperature: 250℃

[0302] • Lower electrode temperature: 350℃

[0303] Film formation time: 8 minutes and 15 seconds

[0304] • Plasma generation power supply frequency: Alternately switch between 13.56 MHz (HF) and 380 kHz (LF). Apply 45 cycles of 13.56 Hz (HF) for 7 seconds and 380 kHz (LF) for 4 seconds as one cycle. Marked as "HFLF" in Table 1.

[0305] RF power: 30W

[0306] • Gas flow rate: SiH4 / NH3 / N2 = 10 / 10 / 2000 sccm

[0307] Example 2

[0308] The plasma generator frequency in the film formation conditions of the inorganic film (silicon nitride film) was changed to 380 kHz (LF), and otherwise the same procedure was followed as in Example 1 to obtain a laminate (supporting substrate / polyimide resin layer / inorganic film). The evaluation results of the obtained laminate are shown in Table 1.

[0309] Example 3

[0310] In the manufacture of the polyamic acid varnish, ODPA and s-BPDA were replaced with DSDA 35.828 g (0.100 mol), APTP was replaced with 4-BAAB 22.825 g (0.100 mol), NMP as the solvent was replaced with GBL, and the amount of diluted GBL was changed. Otherwise, the process was the same as in Example 1 to obtain a polyamic acid varnish with a solids content of 12% by mass. Then, using the polyamic acid varnish obtained herein, the process was carried out in the same manner as in Example 2 to obtain a laminate (supporting substrate / polyimide resin layer / inorganic film). The evaluation results of the obtained laminate are shown in Table 1.

[0311] Example 4

[0312] The film formation time of the inorganic film (silicon nitride film) was changed to 41 minutes and 15 seconds, and the film thickness was changed to 5000 Å. Otherwise, the process was the same as in Example 2, resulting in a laminate (supporting substrate / polyimide resin layer / inorganic film). The evaluation results of the obtained laminate are shown in Table 1.

[0313] Example 5

[0314] The film formation time of the inorganic film (silicon nitride film) was changed to 41 minutes and 15 seconds, and the film thickness was changed to 5000 Å. Otherwise, the process was the same as in Example 3 to obtain a laminate (supporting substrate / polyimide resin layer / inorganic film). The evaluation results of the obtained laminate are shown in Table 1.

[0315] Example 6

[0316] The ODPA and s-BPDA were changed to DSDA 25.080g (0.070 mol) and PMDA 6.544g (0.030 mol), the APTP was changed to 4-BAAB 22.825g (0.100 mol), the film formation time of the inorganic film (silicon nitride film) was changed to 41 minutes and 15 seconds, and the film thickness was changed to 5000. Otherwise, the process was the same as in Example 2, resulting in a laminate (supporting substrate / polyimide resin layer / inorganic film). The evaluation results of the obtained laminate are shown in Table 1.

[0317] Example 7

[0318] The ODPA and s-BPDA were replaced with DSDA 17.914 g (0.050 mol) and PMDA 10.906 g (0.050 mol), and the APTP was replaced with 4-BAAB 22.825 g (0.100 mol). Otherwise, the process was the same as in Example 2, resulting in a laminate (supporting substrate / polyimide resin layer / inorganic film). The evaluation results of the obtained laminate are shown in Table 1.

[0319] Example 8

[0320] The film formation time of the inorganic film (silicon nitride film) was changed to 41 minutes and 15 seconds, and the film thickness was changed to 5000 Å. Otherwise, the process was the same as in Example 7 to obtain a laminate (supporting substrate / polyimide resin layer / inorganic film). The evaluation results of the obtained laminate are shown in Table 1.

[0321] Comparative Example 1

[0322] The plasma generator frequency in the film formation conditions of the inorganic film (silicon nitride film) was changed to 13.56 MHz (HF), and otherwise the same procedure was followed as in Example 1 to obtain a laminate (supporting substrate / polyimide resin layer / inorganic film). The evaluation results of the obtained laminate are shown in Table 1.

[0323] Comparative Example 2

[0324] The lower electrode temperature in the film formation conditions of the inorganic film (silicon nitride film) was changed to 400°C, and the RF power was changed to 70W. Otherwise, the same procedures were followed as in Comparative Example 1 to obtain a laminate (supporting substrate / polyimide resin layer / inorganic film). The evaluation results of the obtained laminate are shown in Table 1.

[0325] [Table 1]

[0326]

[0327] As shown in Table 1, the laminates of the embodiments exhibit excellent film-forming properties and, consequently, excellent heat resistance. Therefore, the laminates of the present invention possess the properties described above, and are thus useful as laminates in semiconductor processes. Specifically, the laminates of the present invention are useful as laminates for semiconductor memories, LSI stacks, CMOS image sensors, MEMS packaging, optical devices, LED applications, and the like.

Claims

1. A laminate having a support substrate, a polyimide resin layer on the support substrate, and an inorganic film on the polyimide resin layer, the glass transition temperature of a polyimide resin constituting the polyimide resin layer being 300°C or higher, and the stress of the inorganic film being a compressive stress.

2. The laminate according to claim 1, wherein The inorganic film contains silicon.

3. The laminate according to claim 1 or 2, wherein The inorganic film is silicon oxide or silicon nitride.

4. The laminate according to any one of claims 1 to 3, wherein The film thickness of the polyimide resin layer is 0.5 to 300 μm.

5. The laminate according to any one of claims 1 to 4, wherein The thickness of the inorganic film is 1 to 1000 nm.

6. The laminate according to any one of claims 1 to 5, wherein The support substrate contains silicon.

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

8. A method for producing a laminate, comprising a step of applying a polyimide resin varnish or a polyimide resin precursor varnish to a support substrate and heating to obtain a polyimide resin layer, and a step of forming an inorganic film having a compressive stress on the polyimide resin layer.

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