Method for manufacturing a circuit board, circuit board precursor with release film, and circuit board precursor with inorganic substrate

Abstract

A method for manufacturing a circuit substrate, comprising: a step A of forming a through-hole in a heat-resistant polymer film; a step B of attaching a release film to a first surface of the heat-resistant polymer film on which the through-hole has been formed; a step C of forming a metal layer on the release film on a second surface side of the heat-resistant polymer film on which the through-hole has been formed and in the through-hole; a step D of peeling the release film from the heat-resistant polymer film after the step C; a step E of preparing an inorganic substrate having a silane coupling agent layer; a step F of attaching the inorganic substrate to the first surface of the heat-resistant polymer film from which the release film has been peeled, with the silane coupling agent layer as an attachment surface, after the step D; a step G of patterning the metal layer after the step F; and a step H of peeling the inorganic substrate from the heat-resistant polymer film after the step G.

Description

Technical Field

[0001] This invention relates to a method for manufacturing a circuit board, a circuit board precursor with a release film, and a circuit board precursor with an inorganic substrate. Background Technology

[0002] In recent years, with the increasing integration of semiconductor devices, there is a need for higher density circuit boards. To this end, the electrode density of IC chips has increased, and circuit boards serving as redistribution layers, such as those used in fan-out panel-level packages, require circuits with minute details. Furthermore, high-density circuit boards are used as wiring layers for mini LEDs (similar to the extremely small LEDs positioned directly below the liquid crystal that make up a liquid crystal display).

[0003] As a method for manufacturing circuit boards, a method is known in which a circuit layer having an insulating layer and a pattern wiring layer is formed on a dummy substrate using thin film forming technology or the like, and then the dummy substrate is peeled off.

[0004] For example, Patent Document 1 discloses a manufacturing method in which a dummy substrate is used, which consists of a carrier layer (substrate) made of metal foil, a release layer with weak peel strength, a copper plating layer and a release protection layer made of insulating resin, which are stacked in sequence. After forming a thin film circuit (circuit layer) on the dummy substrate, the dummy substrate is removed from the thin film circuit. Existing technical documents Patent documents

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2004-311912 Summary of the Invention The problem the invention aims to solve

[0006] In the circuit board manufacturing method disclosed in Patent Document 1, in order to remove the dummy substrate from the thin-film circuit body, firstly, while the copper plating layer and the release protective layer remain on one side of the thin-film circuit body, the carrier layer and the release layer are peeled off. Then, the copper plating layer is removed by a wet etching method using a release agent such as sulfuric acid and hydrogen peroxide, and the release protective layer is removed by a dry etching method such as oxygen plasma (specifically, see paragraphs

[0061] and

[0062] of Patent Document 1).

[0007] Typically, when a circuit board is directly formed on a carrier layer (substrate) made of metal foil using thin-film forming technology, the carrier layer and the circuit board are firmly bonded together and cannot be easily peeled off. In particular, the metal layer formed on the carrier layer thereafter is further firmly bonded to the carrier layer through thermal runaway. For example, when patterning is performed on the metal layer formed on the carrier layer, and further, when multiple patterned metal layers (wiring layers) are formed on top of it, multiple stages of thermal runaway are performed. Therefore, in Patent Document 1, a release layer, a copper plating layer, and a release protection layer are configured between the carrier layer and the thin-film circuit body to achieve the peeling of the carrier layer and the thin-film circuit body.

[0008] However, in the circuit board manufacturing method described above, in order to remove the copper plating layer and peel off the protective layer, the etching solution is adhered to the thin film circuit body, and plasma is irradiated, which may cause damage to the thin film circuit body.

[0009] The present invention was made in view of the above-mentioned problems, and its object is to provide a method for manufacturing a circuit board that can peel the circuit board formed on the inorganic substrate off the inorganic substrate with minimal damage and with fewer subsequent steps. Furthermore, the present invention also provides a circuit board precursor with a release film and a circuit board precursor with an inorganic substrate obtained by implementing the steps of this manufacturing method. Technical means to solve the problem

[0010] The inventors have conducted in-depth research on methods for manufacturing circuit boards. As a result, they discovered that by employing the following configuration, it is possible to peel the circuit board formed on the inorganic substrate from the inorganic substrate with minimal damage and with fewer subsequent steps, thus completing this invention.

[0011] That is, the present invention provides the following content. A method for manufacturing a circuit board, characterized in that it comprises: Process A: Forming through-holes in a heat-resistant polymer film Step B involves attaching a release film to the first side of the heat-resistant polymer film, which has already formed through-holes. Step C: Forming a metal layer on the heat-resistant polymer film on one side of the second surface of the heat-resistant polymer film with through holes and on the release film within the through holes. Step D, following step C, involves peeling the release film from the heat-resistant polymer film. Step E: Preparing an inorganic substrate with a silane coupling agent layer Following step D, step F involves attaching the inorganic substrate to the heat-resistant polymer film, after the release film has been peeled off, using the silane coupling agent layer as the bonding surface. Following step F, step G involves patterning the metal layer. Step H is the step after step G in which the inorganic substrate is peeled off from the heat-resistant polymer film.

[0012] According to the aforementioned configuration, in step C, a metal layer is formed on the release film within the through-hole. Since the release film is easily peeled off, the heat-resistant polymer film can be easily peeled off from the release film even after the metal layer is formed. Furthermore, after the heat-resistant polymer film is peeled off from the release film following the formation of the metal layer, patterning is performed after attachment to the inorganic substrate. Therefore, the metal layer experiences less heat while in contact with the release film. As a result, the adhesion between the metal layer and the release film is suppressed. Furthermore, in step F, a heat-resistant polymer film with a metal layer, peeled from the release film, is attached to the inorganic substrate using the silane coupling agent layer as the bonding surface. The metal layer peeled from the release film (the metal layer exposed through the through-holes) is temporarily attached to the silane coupling agent layer with only moderate adhesion, and subsequently, even under heat treatment, it cannot be firmly fixed to the inorganic substrate. Furthermore, the silane coupling agent layer and the heat-resistant polymer film are only attached with moderate adhesion, and subsequently, even under heat treatment, they cannot be firmly fixed to the inorganic substrate. Therefore, after step G, which patterns the metal layer, the inorganic substrate with the silane coupling agent layer can be easily peeled off from the heat-resistant polymer film by means of peeling or the like. Overall, using the silane coupling agent layer and the heat-resistant polymer film as the interface, the inorganic substrate can be easily peeled off from the heat-resistant polymer film. Because the inorganic substrate can be peeled off from the heat-resistant polymer film by means of tearing, the removal reagents used to peel off the inorganic substrate will not adhere to the patterned metal layer, and there will be no plasma irradiation. As a result, the circuit board (the patterned metal layer) formed on the inorganic substrate can be peeled off from the inorganic substrate with minimal damage. Furthermore, since the inorganic substrate can be peeled off from the heat-resistant polymer film by means of tearing, there are fewer steps that cause damage to the circuit board after peeling the inorganic substrate off from the heat-resistant polymer film. For example, in Patent Document 1, after peeling off the carrier layer and the thin-film circuit body, etching solution and plasma irradiation are required to remove the copper plating layer and peel off the protective layer. However, in this invention, since the inorganic substrate can be peeled off from the heat-resistant polymer film, such treatment is not required. It should be noted that by providing a silane coupling agent layer between the inorganic substrate and the heat-resistant polymer film, the inorganic substrate and the heat-resistant polymer film can be bonded together with appropriate peel strength, and the two can be easily peeled off, as disclosed in, for example, Japanese Patent Application Publication No. 2011-011455.

[0013] In the aforementioned configuration, the heat-resistant polymer film is preferably a polyimide film.

[0014] When the heat-resistant polymer film is a polyimide film, it exhibits excellent heat resistance. Furthermore, when the polymer film is a polyimide film, laser-based hole-opening processing can be appropriately used.

[0015] In the aforementioned configuration, the inorganic substrate is preferably a composite formed by stacking a glass plate, a ceramic plate, a semiconductor wafer, or two or more of these.

[0016] When the inorganic substrate is a composite formed by stacking glass plates, ceramic plates, semiconductor wafers, or two or more of them, it exhibits excellent dimensional stability due to its high elastic modulus and low coefficient of linear expansion. As a result, the manufactured circuit board achieves good dimensional accuracy.

[0017] In addition, the present invention provides the following. A circuit board precursor with a release film, characterized in that, It features a release film, a heat-resistant polymer film with through-holes, and a metal layer. The heat-resistant polymer film is disposed on the release film. The metal layer is disposed on the heat-resistant polymer film and on the release film within the through hole.

[0018] The circuit board precursor with a release film can be obtained by performing the manufacturing method of the circuit board. Because of the aforementioned structure, the release film is easily peeled off, allowing the heat-resistant polymer film to be easily detached from it. Furthermore, after peeling the heat-resistant polymer film from the release film and patterning the metal layer on the heat-resistant polymer film onto the inorganic substrate, there is less thermal stress occurring when the metal layer and the release film are in contact. As a result, adhesion between the metal layer and the release film can be suppressed.

[0019] In addition, the present invention provides the following. A circuit board precursor with an inorganic substrate, characterized in that, It comprises an inorganic substrate and a silane coupling agent layer, as well as a heat-resistant polymer film and a metal layer with through-pores. The silane coupling agent layer is disposed on the inorganic substrate. The heat-resistant polymer film is disposed on the silane coupling agent layer. The metal layer is disposed on the heat-resistant polymer film and on the silane coupling agent layer within the through-hole.

[0020] The circuit board precursor with the inorganic substrate can be obtained by implementing the circuit board manufacturing method. According to the aforementioned configuration, the metal layer within the through-hole adheres to the silane coupling agent layer with only moderate adhesion, and subsequently, even under heat treatment, it cannot be firmly fixed to the inorganic substrate. Furthermore, the silane coupling agent layer and the heat-resistant polymer film adhere with only moderate adhesion, and subsequently, even under heat treatment, they cannot be firmly fixed to the inorganic substrate. Therefore, after the metal layer patterning process G, the inorganic substrate with the silane coupling agent layer can be easily peeled off from the heat-resistant polymer film by peeling or the like. Overall, the inorganic substrate can be easily peeled off from the heat-resistant polymer film using the silane coupling agent layer and the heat-resistant polymer film as the interface. Since the inorganic substrate can be peeled off from the heat-resistant polymer film by peeling or the like, the peeling agent used to peel off the inorganic substrate will not adhere to the patterned metal layer, and there will be no issues such as plasma irradiation. As a result, the circuit board (patterned metal layer) formed on the inorganic substrate can be peeled off from the inorganic substrate with minimal damage. The effects of the invention

[0021] According to the present invention, a method for manufacturing a circuit board is provided that enables the stripping of a circuit board formed on an inorganic substrate from the inorganic substrate with minimal damage. Furthermore, a circuit board precursor with a release film and a circuit board precursor with an inorganic substrate are also provided, obtained by performing the steps of this manufacturing method. Attached Figure Description

[0022] [ Figure 1 [A cross-sectional schematic diagram illustrating the manufacturing method of the circuit board involved in this embodiment.] [ Figure 2 [A cross-sectional schematic diagram illustrating the manufacturing method of the circuit board involved in this embodiment.] [ Figure 3 [A cross-sectional schematic diagram illustrating the manufacturing method of the circuit board involved in this embodiment.] [ Figure 4 [A cross-sectional schematic diagram illustrating the manufacturing method of the circuit board involved in this embodiment.] [ Figure 5 [A cross-sectional schematic diagram illustrating the manufacturing method of the circuit board involved in this embodiment.] [ Figure 6 [A cross-sectional schematic diagram illustrating the manufacturing method of the circuit board according to this embodiment.] Figure 7 [A cross-sectional schematic diagram illustrating the manufacturing method of the circuit board according to this embodiment.] Figure 8 [A cross-sectional schematic diagram illustrating the manufacturing method of the circuit board according to this embodiment.] Figure 9 [A cross-sectional schematic diagram illustrating the manufacturing method of the circuit board according to this embodiment.] Figure 10[A cross-sectional schematic diagram illustrating the manufacturing method of the circuit board according to this embodiment.] Figure 11 [A cross-sectional schematic diagram illustrating the manufacturing method of the circuit board involved in this embodiment.] Symbol Explanation 10 Heat-resistant polymer film with double-sided protective film 12 Heat-resistant polymer film Page 2 of 12b Page 12a 13 through holes 14. First protective film 16 Second protective film 18. Release film 20 metal layers 21. Wiring layer (patterned metal layer) 30 Circuit board precursors with release film 40 Inorganic substrate 42 Silane Coupling Agent Layer 44 Adhesive layer 46. ​​Second heat-resistant polymer film 48 through holes 49. Second wiring layer 50 Circuit board precursors with inorganic substrate 52 Second wiring layer 60 circuit board Detailed Implementation

[0023] Hereinafter, embodiments of the present invention will be described. The following description pertains to a method for manufacturing a circuit board, including a circuit board precursor with a release film and a circuit board precursor with an inorganic substrate.

[0024] [Manufacturing method of circuit board] The method for manufacturing a circuit board according to this embodiment includes the following steps: Process A: Forming through-holes in a heat-resistant polymer film Step B involves attaching a release film to the first side of the heat-resistant polymer film, which has already formed through-holes. Step C: Forming a metal layer on the heat-resistant polymer film on one side of the second surface of the heat-resistant polymer film with through holes and on the release film within the through holes. Step D, following step C, involves peeling the release film from the heat-resistant polymer film. Step E: Preparing an inorganic substrate with a silane coupling agent layer Following step D, step F involves attaching the inorganic substrate to the heat-resistant polymer film, after the release film has been peeled off, using the silane coupling agent layer as the bonding surface. Following step F, step G involves patterning the metal layer. Step H is the step after step G in which the inorganic substrate is peeled off from the heat-resistant polymer film.

[0025] <Process A> Regarding the method for manufacturing the circuit board according to this embodiment, firstly, through holes are formed in a heat-resistant polymer film. The heat-resistant polymer film can be prepared with protective films attached to both sides, with protective films attached to only one side, or with no protective films attached to either side. When preparing a heat-resistant polymer film with protective films on both sides, the formation of through holes can be carried out with the protective films on both sides, after peeling off the protective films on both sides, or after peeling off the protective film on only one side. When preparing a heat-resistant polymer film with the protective film only attached to one side, the formation of through holes can be carried out while the protective film on that side is attached, or it can be carried out after only peeling off the protective film on that side. In the embodiments described below, the through holes are formed when the heat-resistant polymer film with the protective film attached to both sides is prepared.

[0026] Figures 1 to 11 This is a cross-sectional schematic diagram used to illustrate the manufacturing method of the circuit board involved in this embodiment.

[0027] like Figure 1 As shown, in the circuit board manufacturing method of this embodiment, firstly, a heat-resistant polymer film 10 with protective films on both sides is prepared. The heat-resistant polymer film 10 with protective films on both sides has a heat-resistant polymer film 12, a first protective film 14 attached to the first side 12a of the heat-resistant polymer film 12, and a second protective film 16 attached to the second side 12b of the heat-resistant polymer film 12.

[0028] Next, as Figure 2 As shown, through-holes 13 are formed in the heat-resistant polymer film 12. In this embodiment, the through-holes 13 are formed in the heat-resistant polymer film 12 with protective films (first protective film 14 and second protective film 16) attached to both sides of the heat-resistant polymer film 12. Therefore, through-holes are also formed in the first protective film 14 and the second protective film 16. It should be noted that an electrode for external connection is ultimately formed in the through-hole 13. Therefore, the through-hole 13 is formed at the position where the electrode for external connection should be formed.

[0029] The through-hole 13 can be formed using existing known methods, such as laser drilling. Alternatively, when forming a heat-resistant polymer film 12 using a photosensitive resin, the through-hole 13 can be formed by developing after irradiation with light through a photomask with a pattern corresponding to the through-hole 13. In this case, it is preferable to perform light irradiation and development without attaching a protective film to the side where the photomask is disposed. The shape of the through hole 13 (shape from a planar perspective) is not particularly limited, but it is preferably circular, and the diameter can also be set appropriately, for example, it can be set to 300μm to 5μm.

[0030] The following describes the heat-resistant polymer film, the first protective film, and the second protective film.

[0031] <Heat-resistant polymer film> In this specification, the melting point of the heat-resistant polymer is 250°C or higher, preferably 300°C or higher, and more preferably 400°C or higher. Furthermore, the glass transition temperature of the polymer is 200°C or higher, preferably 320°C or higher, and more preferably 380°C or higher. Hereinafter, to avoid complexity, it may simply be referred to as a polymer. In this specification, the melting point and glass transition temperature can be determined using differential thermal analysis (DSC). It should be noted that the heat-resistant polymer film is not limited as long as it possesses practical strength through existing methods such as glass fiber reinforcement and high-concentration filler filling. It should be noted that when the melting point exceeds 500°C, the melting point can be determined by visually observing the heat deformation behavior when heated at that temperature.

[0032] Examples of heat-resistant polymer films (hereinafter also referred to simply as polymer films) include: polyimide, polyamide-imide, polyether-imide, polyimide resins called fluorinated polyimide (e.g., aromatic polyimide resins, alicyclic polyimide resins); polyethylene, polypropylene, polyethylene terephthalate, polyethylene terephthalate, copolyesters called polyethylene 2,6-naphthalate (e.g., fully aromatic polyesters, semi-aromatic polyesters); copoly(meth)acrylates represented by polymethyl methacrylate; polycarbonate; polyamide; polysulfone; polyethersulfone; polyetherketone; cellulose acetate; cellulose nitrate; aromatic polyamide; polyvinyl chloride; polyphenols; polyarylates; polyphenylene sulfide; polyphenylene ether; polystyrene, etc. However, since the polymer membrane is intended for use with heat treatment processes above 300°C, the number of polymer membranes practically applicable among the listed polymer membranes is limited. Preferably, the polymer membrane is made of so-called super engineering plastics, and more specifically, examples include: aromatic polyimide membranes, aromatic amide membranes, aromatic amide-imide membranes, aromatic benzoxazole membranes, aromatic benzothiazole membranes, and aromatic benzimidazole membranes.

[0033] The following describes in detail a polyimide-based resin film (sometimes also called a polyimide film), which is one example of the polymer film. Typically, a polyamic acid (polyimide precursor) solution, obtained by reacting a diamine with a tetracarboxylic acid in a solvent, is coated onto a support for making a polyimide film, dried, and a green film (hereinafter also called a "polyamic acid film") is produced. Further, the green film is subjected to high-temperature heat treatment on the support for making the polyimide film, or in a state peeled from the support, to undergo a dehydration and ring-closing reaction, thereby obtaining a polyimide-based resin film.

[0034] The coating of polyamic acid (polyimide precursor) solutions can be carried out using, for example, existing known coating methods such as spin coating, doctor blade coating, applicator, comma coater, screen printing, slot coating, reverse roller coating, dip coating, curtain coating, and slot die coating.

[0035] There are no particular limitations on the diamines that constitute polyamic acid; aromatic diamines, aliphatic diamines, and alicyclic diamines commonly used in the synthesis of polyimides can be used. From the viewpoint of heat resistance, aromatic diamines are preferred. Diamines can be used alone or in combination of two or more.

[0036] As a diamine, there are no particular limitations; examples include oxodiphenylamine (bis(4-aminophenyl) ether) and p-phenylenediamine (1,4-phenylenediamine).

[0037] As the tetracarboxylic acids constituting polyamic acids, aromatic tetracarboxylic acids (including their anhydrides), aliphatic tetracarboxylic acids (including their anhydrides), and alicyclic tetracarboxylic acids (including their anhydrides) commonly used in the synthesis of polyimides can be used. When they are anhydrides, there can be one or two anhydride structures within the molecule, preferably two anhydride structures (dianhydrides). Tetracarboxylic acids can be used alone or in combination of two or more.

[0038] There are no particular limitations on what constitutes a tetracarboxylic acid; examples include pyromellitic dianhydride and 3,3',4,4'-biphenyltetracarboxylic acid dianhydride.

[0039] The polyimide film can be a transparent polyimide film.

[0040] The following description focuses on a colorless transparent polyimide as an example of the polymer film. Hereinafter, for the sake of simplicity, it will simply be referred to as transparent polyimide. Regarding the transparency of the transparent polyimide, a total light transmittance of 75% or more is preferred. More preferably, it is 80% or more, further preferably 85% or more, even more preferably 87% or more, and particularly preferably 88% or more. The upper limit of the total light transmittance of the transparent polyimide is not particularly limited, but for use as a flexible circuit board, the upper limit is preferably 98% or less, more preferably 97% or less. The colorless transparent polyimide in this invention is preferably a polyimide with a total light transmittance of 75% or more.

[0041] Examples of aromatic tetracarboxylic acids used to prepare colorless and highly transparent polyimides include: 4,4'-(2,2-hexafluoroisopropylidene)diphthalic acid, 4,4'-oxophthalic acid, p-phenylene-bisbenzotriester dianhydride, bis(1,3-dioxo-1,3-dihydro-2-benzofuran-5-yl)phenyl-1,4-dicarboxylate, 4,4'-[4,4'-(3-oxo-1,3-dihydro-2-benzofuran-1,1-diyl)bis(phenyl-1,4-diyloxy)]diphenyl-1,2-dicarboxylic acid, 3,3',4,4'-benzophenone tetracarboxylic acid, and 4,4'-[(3-oxo-1,3-dihydro-2-benzofuran-1,1-diyl)bis(toluene-2, [5-diyloxy]diphenyl-1,2-dicarboxylic acid, 4,4'-[(3-oxo-1,3-dihydro-2-benzofuran-1,1-diyl)bis(1,4-xylyl-2,5-diyloxy)]diphenyl-1,2-dicarboxylic acid, 4,4'-[4,4'-(3-oxo-1,3-dihydro-2-benzofuran-1,1-diyl)bis(4-isopropyl-toluene-2,5-diyloxy)]diphenyl-1,2-dicarboxylic acid, 4,4'-[4,4'-(3-oxo-1,3-dihydro-2-benzofuran-1,1-diyl)bis(naphthalene-1,4-diyloxy)]diphenyl-1,2-dicarboxylic acid, 4,4'-[4,4'-(3H-2,1-benzoxoxothiapentane)] -1,1-dioxide-3,3-diyl)bis(benzyl-1,4-diyloxy)]diphenyl-1,2-dicarboxylic acid, 4,4'-benzophenone tetracarboxylic acid, 4,4'-[(3H-2,1-benzoxythiapentane)-1,1-dioxide-3,3-diyl)bis(toluene-2,5-diyloxy)]diphenyl-1,2-dicarboxylic acid, 4,4'-[(3H-2,1-benzoxythiapentane)-1,1-dioxide-3,3-diyl)bis(1,4-xylene-2,5-diyloxy)]diphenyl-1,2-dicarboxylic acid, 4,4'-[4,4'-(3H-2,1-benzoxythiapentane)-1,1-dioxide-3,3-diyl)bis(4-isopropyl-methyl [Benzene-2,5-dioxy]diphenyl-1,2-dicarboxylic acid, 4,4'-[4,4'-(3H-2,1-benzoxylthiapentane)-1,1-dioxide-3,3-diyl)bis(naphthalene-1,4-dioxy)]diphenyl-1,2-dicarboxylic acid, 3,3',4,4'-benzophenone tetracarboxylic acid, 3,3',4,4'-benzophenone tetracarboxylic acid, 3,3',4,4'-diphenylsulfone tetracarboxylic acid, 3,3',4,4'-biphenyltetracarboxylic acid, 2,3,3',4'-biphenyltetracarboxylic acid, pyromellitic acid, 4,4'-[spiro(xanthan-9,9'-fluorene)-2,6-diylbis(oxycarbonyl)]diphthalic acid, 4,4'-[spiro(xanthan-9,9'-fluorene)-3,[6-Dimethylbis(oxycarbonyl)] phthalic acid and other tetracarboxylic acids and their anhydrides. Among these, dianhydrides having two anhydride structures are suitable, and particularly preferred are 4,4'-(2,2-hexafluoroisopropylidene) phthalic acid dianhydride and 4,4'-oxophthalic acid dianhydride. It should be noted that aromatic tetracarboxylic acids can be used alone or in combination of two or more. The copolymerization amount of the aromatic tetracarboxylic acids, when heat resistance is important, is preferably 50% by mass or more of the total tetracarboxylic acids, more preferably 60% by mass or more, further preferably 70% by mass or more, even more preferably 80% by mass or more, particularly preferably 90% by mass or more, and even 100% by mass is not unfavorable.

[0042] Examples of alicyclic tetracarboxylic acids include: 1,2,3,4-cyclobutanetetracarboxylic acid, 1,2,3,4-cyclopentanetetracarboxylic acid, 1,2,3,4-cyclohexanetetracarboxylic acid, 1,2,4,5-cyclohexanetetracarboxylic acid, 3,3',4,4'-dicyclohexyltetracarboxylic acid, bicyclo[2,2,1]heptane-2,3,5,6-tetracarboxylic acid, bicyclo[2,2,2]octane-2,3,5,6-tetracarboxylic acid, bicyclo[2,2,2]oct-7-enyl-2,3,5,6-tetracarboxylic acid, tetrahydroanthracene-2,3,6,7-tetracarboxylic acid, and tetradecahydro-1,4:5,8:9,10-trimethanoanthracene-2,3,6,7-tetracarboxylic acid. Decahydronaphthalene-2,3,6,7-tetracarboxylic acid, decahydro-1,4:5,8-dimethanonaphthalene-2,3,6,7-tetracarboxylic acid, decahydro-1,4-ethahydro-5,8-methanonaphthalene-2,3,6,7-tetracarboxylic acid, norbornane-2-spiro-α-cyclopentanone-α'-spiro-2”-norbornane-5,5”,6,6”-tetracarboxylic acid (also known as "norbornane-2-spiro-2'-cyclopentanone-5'-spiro-2”-norbornane-5,5”,6,6”-tetracarboxylic acid"), methylnorbornane-2-spiro-α-cyclopentanone-α'-spiro-2”-(methylnorbornane)- 5,5”,6,6”-Tetracarboxylic acid, norbornane-2-spiro-α-cyclohexanone-α'-spiro-2”-norbornane-5,5”,6,6”-tetracarboxylic acid (also known as “norbornane-2-spiro-2'-cyclohexanone-6'-spiro-2”-norbornane-5,5”,6,6”-tetracarboxylic acid”), methylnorbornane-2-spiro-α-cyclohexanone-α'-spiro-2”-(methylnorbornane)-5,5”,6,6”-tetracarboxylic acid, norbornane-2-spiro-α-cyclopropanone-α'-spiro-2”-norbornane-5,5”,6,6”-tetracarboxylic acid, norbornane-2-spiro-α-cyclobutanone-α'-spiro-2”-norbornane-5,5”,6,6”-tetracarboxylic acid, norbornane -2-spiro-α-cycloheptanone-α'-spiro-2”-norbornane-5,5”,6,6”-tetracarboxylic acid, norbornane-2-spiro-α-cyclooctanone-α'-spiro-2”-norbornane-5,5”,6,6”-tetracarboxylic acid, norbornane-2-spiro-α-cyclononanone-α'-spiro-2”-norbornane-5,5”,6,6”-tetracarboxylic acid, norbornane-2-spiro-α-cyclodecanone-α'-spiro-2”-norbornane-5,5”,6,6”-tetracarboxylic acid, norbornane-2-spiro-α-cycloundecanone-α'-spiro-2”-norbornane-5,5”,6,6”-tetracarboxylic acid, norbornane-2-spiro-α-cyclododecanone-α'-spiro-2”-norbornane-5,5”,6,6”-Tetracarboxylic acid, norbornane-2-spiro-α-cyclotridecanone-α'-spiro-2”-norbornane-5,5”,6,6”-tetracarboxylic acid, norbornane-2-spiro-α-cyclotetradecadecanone-α'-spiro-2”-norbornane-5,5”,6,6”-tetracarboxylic acid, norbornane-2-spiro-α-cyclopentadecanone-α'-spiro-2”-norbornane-5,5”,6,6”-tetracarboxylic acid, norbornane-2-spiro-α-(methylcyclopentanone)-α'-spiro-2”-norbornane-5,5”,6,6”-tetracarboxylic acid, norbornane-2-spiro-α-(methylcyclohexanone)-α'-spiro-2”-norbornane-5,5”,6,6”-tetracarboxylic acid, and their anhydrides. Among these, dianhydrides having two anhydride structures are suitable, particularly preferably 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride, 1,2,3,4-cyclohexanetetracarboxylic acid dianhydride, and 1,2,4,5-cyclohexanetetracarboxylic acid dianhydride, more preferably 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride and 1,2,4,5-cyclohexanetetracarboxylic acid dianhydride, and even more preferably 1,2,3,4-cyclobutanetetracarboxylic acid dianhydride. It should be noted that these can be used alone or in combination of two or more. The copolymerization amount of the alicyclic tetracarboxylic acid is preferably 50% by mass or more of the total tetracarboxylic acid, more preferably 60% by mass or more, even more preferably 70% by mass or more, and even more preferably 80% by mass or more, particularly preferably 90% by mass or more, and even 100% by mass is not unfavorable, provided transparency is important.

[0043] As tricarboxylic acids, aromatic tricarboxylic acids such as trimellitic acid, 1,2,5-naphthalenetricarboxylic acid, diphenyl ether-3,3',4'-tricarboxylic acid, and diphenyl sulfone-3,3',4'-tricarboxylic acid, or hydrides of the above aromatic tricarboxylic acids such as hexahydrotriphenylamine, alkylene glycol trimellitic acid esters such as ethylene glycol diphenylamine ester, propylene glycol diphenylamine ester, 1,4-butanediol diphenylamine ester, and polyethylene glycol diphenylamine ester, as well as their monohydric anhydrides and esters. Among these, monohydric anhydrides having one anhydride structure are suitable, and trimellitic anhydride and hexahydrotriphenylamine anhydride are particularly preferred. It should be noted that these can be used alone or in combination.

[0044] Examples of dicarboxylic acids include: aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, phthalic acid, naphthalenedicarboxylic acid, and 4,4'-oxodibenzoic acid; or hydrides of the above aromatic dicarboxylic acids such as 1,6-cyclohexanedicarboxylic acid; oxalic acid; succinic acid; glutaric acid; adipic acid; pimelic acid; octanoic acid; azelaic acid; sebacic acid; undecanoic acid; dodecanoic acid; 2-methylsuccinic acid; and their acyl chlorides or esters. Among these, aromatic dicarboxylic acids and their hydrides are suitable, and terephthalic acid, 1,6-cyclohexanedicarboxylic acid, and 4,4'-oxodibenzoic acid are particularly preferred. It should be noted that dicarboxylic acids can be used alone or in combination.

[0045] There are no particular limitations on the diamines or isocyanates used to obtain colorless and highly transparent polyimides. Aromatic diamines, aliphatic diamines, alicyclic diamines, aromatic diisocyanates, aliphatic diisocyanates, and alicyclic diisocyanates commonly used in the synthesis of polyimides, polyamide-imides, and polyamides can be used. From the viewpoint of heat resistance, aromatic diamines are preferred, and from the viewpoint of transparency, alicyclic diamines are preferred. Furthermore, when using aromatic diamines with a benzoxazole structure, they exhibit high heat resistance, high elastic modulus, low thermal shrinkage, and a low coefficient of linear expansion. Diamines and isocyanates can be used alone or in combination of two or more.

[0046] Examples of aromatic diamines include, for instance: 2,2'-dimethyl-4,4'-diaminobiphenyl, 1,4-bis[2-(4-aminophenyl)-2-propyl]benzene, 1,4-bis(4-amino-2-trifluoromethylphenoxy)benzene, 2,2'-ditrifluoromethyl-4,4'-diaminobiphenyl, 4,4'-bis(4-aminophenoxy)biphenyl, 4,4'-bis(3-aminophenoxy)biphenyl, bis[4-(3-aminophenoxy)phenyl]ketone, bis[4-(3-aminophenoxy)phenyl]sulfide, bis[4-(3-aminophenoxy)phenyl]sulfone, 2,2-bis[4-(3-aminophenoxy)phenyl]propane, 2,2-bis[4-(3-aminophenoxy)phenyl]-1,1,1 3,3,3-Hexafluoropropane, m-phenylenediamine, o-phenylenediamine, p-phenylenediamine, m-aminobenzylamine, p-aminobenzylamine, 4-amino-N-(4-aminophenyl)benzamide, 3,3'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 2,2'-trifluoromethyl-4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl sulfide, 3,4'-diaminodiphenyl sulfide, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenyl sulfoxide, 3,4'-diaminodiphenyl sulfoxide, 4,4'-diaminodiphenyl sulfoxide, 3,3'-diaminodiphenyl sulfone, 3,4'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone Benzene, 3,4'-diaminobenzophenone, 4,4'-diaminobenzophenone, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, bis[4-(4-aminophenoxy)phenyl]methane, 1,1-bis[4-(4-aminophenoxy)phenyl]ethane, 1,2-bis[4-(4-aminophenoxy)phenyl]ethane, 1,1-bis[4-(4-aminophenoxy)phenyl]propane, 1,2-bis[4-(4-aminophenoxy)phenyl]propane, 1,3-bis[4-(4-aminophenoxy)phenyl]propane, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, 1,1-bis[4-(4-aminophenoxy)phenyl]propane Butane, 1,3-bis[4-(4-aminophenoxy)phenyl]butane, 1,4-bis[4-(4-aminophenoxy)phenyl]butane, 2,2-bis[4-(4-aminophenoxy)phenyl]butane, 2,3-bis[4-(4-aminophenoxy)phenyl]butane, 2-[4-(4-aminophenoxy)phenyl]-2-[4-(4-aminophenoxy)-3-methylphenyl]propane, 2,2-bis[4-(4-aminophenoxy)-3-methylphenyl]propane, 2-[4-(4-aminophenoxy)phenyl]-2-[4-(4-aminophenoxy)-3,5-dimethylphenyl]propane, 2,2-bis[4-(4-aminophenoxy)-3,5-dimethylphenyl]propane, 2,2-Bis[4-(4-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, 1,4-bis(3-aminophenoxy)benzene, 1,3-bis(3-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 4,4'-bis(4-aminophenoxy)biphenyl, bis[4-(4-aminophenoxy)phenyl]ketone, bis[4-(4-aminophenoxy)phenyl]sulfide, bis[4-(4-aminophenoxy)phenyl]sulfoxide, bis[4-(4-aminophenoxy)phenyl]sulfone, bis[4-(3-aminophenoxy)phenyl]ether, bis[4-(4-aminophenoxy)phenyl]ether, 1,3-bis[4-(4-aminophenoxy)benzoyl]benzene, 1,3-bis[4-(3-aminophenoxy)benzoyl]benzene [4-(3-aminophenoxy)benzoyl]benzene, 1,4-bis[4-(3-aminophenoxy)benzoyl]benzene, 4,4'-bis[(3-aminophenoxy)benzoyl]benzene, 1,1-bis[4-(3-aminophenoxy)phenyl]propane, 1,3-bis[4-(3-aminophenoxy)phenyl]propane, 3,4'-diaminodiphenyl sulfide, 2,2-bis[3-(3-aminophenoxy)phenyl]-1,1,1,3,3,3-hexafluoropropane, bis[4-(3-aminophenoxy)phenyl]methane, 1,1-bis[4-(3-aminophenoxy)phenyl]ethane, 1,2-bis[4-(3-aminophenoxy)phenyl]ethane, bis[4-(3-aminophenoxy)phenyl]sulfoxide, 4,4'-bis[3-(4-(3-aminophenoxy)phenyl]sulfoxide, [-aminophenoxy)benzoyl]diphenyl ether, 4,4'-bis[3-(3-aminophenoxy)benzoyl]diphenyl ether, 4,4'-bis[4-(4-amino-α,α-dimethylbenzyl)phenoxy]benzophenone, 4,4'-bis[4-(4-amino-α,α-dimethylbenzyl)phenoxy]diphenyl sulfone, bis[4-{4-(4-aminophenoxy)phenoxy}phenyl]sulfone, 1,4-bis[4-(4-aminophenoxy)phenoxy-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(4-aminophenoxy)phenoxy-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(4-aminophenoxy)phenoxy-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(4-amino-6-trifluoromethylphenoxy) ... [4-(4-amino-6-fluorophenoxy)-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(4-amino-6-methylphenoxy)-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(4-amino-6-cyanophenoxy)-α,α-dimethylbenzyl]benzene, 3,3'-diamino-4,4'-diphenoxybenzophenone, 4,4'-diamino-5,5'-diphenoxybenzophenone, 3,4'-diamino-4,5'-diphenoxybenzophenone, 3,3'-diamino-4-phenoxybenzophenone, 4,4'-diamino-5-phenoxybenzophenone, 3,4'-diamino-4-phenoxybenzophenone, 3,4'-diamino-5'-phenoxybenzophenone, 3,3'-diamino-4...4'-Diphenyloxybenzophenone, 4,4'-diamino-5,5'-diphenyloxybenzophenone, 3,4'-diamino-4,5'-diphenyloxybenzophenone, 3,3'-diamino-4-biphenyloxybenzophenone, 4,4'-diamino-5-biphenyloxybenzophenone, 3,4'-diamino-4-biphenyloxybenzophenone, 3,4'-diamino-5'-biphenyloxybenzophenone, 1,3-bis(3-amino-4-phenoxybenzoyl)benzene, 1,4-bis(3-amino-4-phenoxybenzoyl)benzene, 1,3-bis(4-amino-5-phenoxybenzoyl)benzene, 1,4-bis(4-amino-5-phenoxybenzoyl)benzene, 1,3-bis(3-amino-4-biphenyloxybenzoyl)benzene Benzene, 1,4-bis(3-amino-4-biphenoxybenzoyl)benzene, 1,3-bis(4-amino-5-biphenoxybenzoyl)benzene, 1,4-bis(4-amino-5-biphenoxybenzoyl)benzene, 2,6-bis[4-(4-amino-α,α-dimethylbenzyl)phenoxy]benzonitrile, 4,4'-[9H-fluorene-9,9-diyl]bisbenzene Amines (also known as "9,9-bis(4-aminophenyl)fluorene"), spiro(xanthon-9,9'-fluorene)-2,6-diylbis(oxycarbonyl)]bisaniline, 4,4'-[spiro(xanthon-9,9'-fluorene)-2,6-diylbis(oxycarbonyl)]bisaniline, 4,4'-[spiro(xanthon-9,9'-fluorene)-3,6-diylbis(oxycarbonyl)]bisaniline, etc. Furthermore, some or all of the hydrogen atoms on the aromatic ring of the above-mentioned aromatic diamines can be replaced by halogen atoms, alkyl or alkoxy groups having 1 to 3 carbon atoms, or cyano groups. Further, some or all of the hydrogen atoms in the alkyl or alkoxy groups having 1 to 3 carbon atoms can also be replaced by halogen atoms. Furthermore, there are no particular limitations on aromatic diamines having the benzoxazole structure, and examples include: 5-amino-2-(p-aminophenyl)benzoxazole, 6-amino-2-(p-aminophenyl)benzoxazole, 5-amino-2-(m-aminophenyl)benzoxazole, 6-amino-2-(m-aminophenyl)benzoxazole, 2,2'-p-phenylenebis(5-aminobenzoxazole), 2,2'-p-phenylenebis(6-aminobenzoxazole), 1-(5-aminobenzoxazolone)-4-(6-aminobenzoxazolone)benzene, 2,6-(4,4'-diaminobenzoxazole)benzene, etc. 2,6-(4,4'-diaminodiphenyl)benzo[1,2-d:4,5-d']bisoxazole, 2,6-(3,4'-diaminodiphenyl)benzo[1,2-d:5,4-d']bisoxazole, 2,6-(3,4'-diaminodiphenyl)benzo[1,2-d:5,4-d']bisoxazole, 2,6-(3,4'-diaminodiphenyl)benzo[1,2-d:4,5-d']bisoxazole, 2,6-(3,3'-diaminodiphenyl)benzo[1,2-d:5,4-d']bisoxazole, 2,6-(3,3'-diaminodiphenyl)benzo[1,2-d:4,5-d']bisoxazole, etc. Among these, 2,2'-ditrifluoromethyl-4,4'-diaminobiphenyl, 4-amino-N-(4-aminophenyl)benzamide, 4,4'-diaminodiphenyl sulfone, and 3,3'-diaminobenzophenone are particularly preferred. It should be noted that aromatic diamines can be used alone or in combination.

[0047] Examples of alicyclic diamines include: 1,4-diaminocyclohexane, 1,4-diamino-2-methylcyclohexane, 1,4-diamino-2-ethylcyclohexane, 1,4-diamino-2-n-propylcyclohexane, 1,4-diamino-2-isopropylcyclohexane, 1,4-diamino-2-n-butylcyclohexane, 1,4-diamino-2-isobutylcyclohexane, 1,4-diamino-2-sec-butylcyclohexane, 1,4-diamino-2-tert-butylcyclohexane, and 4,4'-methylenebis(2,6-dimethylcyclohexylamine). Among these, 1,4-diaminocyclohexane and 1,4-diamino-2-methylcyclohexane are particularly preferred, and 1,4-diaminocyclohexane is more preferred. It should be noted that alicyclic diamines can be used alone or in combination.

[0048] Examples of diisocyanates include, for instance: diphenylmethane-2,4'-diisocyanate, 3,2'- or 3,3'- or 4,2'- or 4,3'- or 5,2'- or 5,3'- or 6,2'- or 6,3'-dimethyldiphenylmethane-2,4'-diisocyanate, 3,2'- or 3,3'- or 4,2'- or 4,3'- or 5,2'- or 5,3'- or 6,2'- or 6,3'-diethyldiphenylmethane. -2,4'-diisocyanate, 3,2'- or 3,3'- or 4,2'- or 4,3'- or 5,2'- or 5,3'- or 6,2'- or 6,3'-dimethoxydiphenylmethane-2,4'-diisocyanate, diphenylmethane-4,4'-diisocyanate, diphenylmethane-3,3'-diisocyanate, diphenylmethane-3,4'-diisocyanate, diphenyl ether-4,4'-diisocyanate, benzophenone-4,4'-di... Isocyanates, diphenyl sulfone-4,4'-diisocyanate, toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, m-xylene diisocyanate, p-xylene diisocyanate, naphthalene-2,6-diisocyanate, 4,4'-(2,2-bis(4-phenoxyphenyl)propane)diisocyanate, 3,3'- or 2,2'-dimethylbiphenyl-4,4'-diisocyanate, 3,3'- or 2,2'-diethylbiphenyl- Aromatic diisocyanates such as 4,4'-diisocyanate, 3,3'-dimethoxybiphenyl-4,4'-diisocyanate, and 3,3'-diethoxybiphenyl-4,4'-diisocyanate, as well as diisocyanates that have been hydrogenated (e.g., isophorone diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, hexamethylene diisocyanate), etc. Among these, from the viewpoints of low hygroscopicity, dimensional stability, price, and polymerizability, diphenylmethane-4,4'-diisocyanate, toluene-2,4-diisocyanate, toluene-2,6-diisocyanate, 3,3'-dimethylbiphenyl-4,4'-diisocyanate or naphthalene-2,6-diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and 1,4-cyclohexane diisocyanate are preferred. It should be noted that diisocyanates can be used alone or in combination.

[0049] In this embodiment, the polymer film is preferably a polyimide film. When the polymer film is a polyimide film, it exhibits excellent heat resistance. Furthermore, when the polymer film is a polyimide film, laser processing can be appropriately used for hole opening.

[0050] The thickness of the polymer film is preferably 3 μm or more, more preferably 7 μm or more, even more preferably 14 μm or more, and even more preferably 20 μm or more. There is no particular upper limit to the thickness of the polymer film, but when used as a flexible circuit substrate, it is preferably 250 μm or less, more preferably 100 μm or less, and even more preferably 50 μm or less.

[0051] The average coefficient of linear expansion (CTE) of the polymer film between 30°C and 250°C is preferably 50 ppm / K or less. More preferably, it is 45 ppm / K or less, even more preferably 40 ppm / K or less, even more preferably 30 ppm / K or less, and particularly preferably 20 ppm / K or less. Furthermore, it is preferably -5 ppm / K or more, more preferably -3 ppm / K or more, and even more preferably 1 ppm / K or more. When the CTE is within the aforementioned range, a small difference between the coefficient of linear expansion of the conventional support (inorganic substrate) and the CTE can be maintained, thus preventing peeling of the polymer film and the inorganic substrate, or warping of the entire support, even during heating processes. Here, CTE refers to a factor representing reversible shrinkage relative to temperature. It should be noted that the CTE of the polymer film refers to the average value of the CTE in the coating direction (MD direction) and the CTE in the width direction (TD direction) of the polymer solution or polymer precursor solution.

[0052] When the polymer film is a transparent polyimide film, its yellowness index (hereinafter also referred to as "yellowness index" or "YI") is preferably 10 or less, more preferably 7 or less, further preferably 5 or less, and even more preferably 3 or less. The lower limit of the yellowness index of the transparent polyimide is not particularly limited, but when used as a flexible circuit board, it is preferably 0.1 or more, more preferably 0.2 or more, and even more preferably 0.3 or more.

[0053] When the polymer film is a transparent polyimide film, the haze value is preferably 1.0 or less, more preferably 0.8 or less, even more preferably 0.5 or less, and even more preferably 0.3 or less. There is no particular limitation on the lower limit; industrially, a value of 0.01 or more is acceptable, and even a value of 0.05 or more is not a problem.

[0054] The thermal shrinkage rate of the polymer film between 30°C and 500°C is preferably less than ±0.9%, more preferably less than ±0.6%. Thermal shrinkage rate is a factor that represents irreversible shrinkage with respect to temperature.

[0055] The tensile breaking strength of the polymer film is preferably 60 MPa or higher, more preferably 80 MPa or higher, and even more preferably 100 MPa or higher. There is no particular upper limit to the tensile breaking strength; in fact, it is approximately below 1000 MPa. A tensile breaking strength of 60 MPa or higher can prevent the polymer film from breaking during peeling from the inorganic substrate. It should be noted that the tensile breaking strength of the polymer film refers to the average of the tensile breaking strength in the running direction (MD direction) and the tensile breaking strength in the width direction (TD direction).

[0056] The tensile elongation at break of the polymer membrane is preferably 1% or more, more preferably 5% or more, and even more preferably 10% or more. When the tensile elongation at break is 1% or more, the operability is excellent. It should be noted that the tensile elongation at break of the polymer membrane refers to the average of the tensile elongation at break in the running direction (MD direction) and the tensile elongation at break in the width direction (TD direction).

[0057] The tensile modulus of the polymer film is preferably 2.5 GPa or higher, more preferably 3 GPa or higher, and even more preferably 4 GPa or higher. When the tensile modulus is 2.5 GPa or higher, the polymer film experiences less tensile deformation when peeled from the inorganic substrate, resulting in excellent operability. The tensile modulus is preferably 20 GPa or lower, more preferably 15 GPa or lower, and even more preferably 12 GPa or lower. When the tensile modulus is 20 GPa or lower, the polymer film can be used as a flexible film. It should be noted that the tensile modulus of the polymer film refers to the average of the tensile modulus in the running direction (MD direction) and the tensile modulus in the width direction (TD direction).

[0058] The thickness unevenness of the polymer membrane is preferably 20% or less, more preferably 12% or less, even more preferably 7% or less, and particularly preferably 4% or less. When the thickness unevenness exceeds 20%, it tends to become difficult to apply to narrow areas. It should be noted that the membrane thickness unevenness can be determined, for example, by measuring the membrane thickness at approximately 10 randomly selected points on the membrane being measured using a contact thickness gauge, and the membrane thickness unevenness can be calculated based on the following formula. Membrane thickness non-uniformity (%) = 100 × (maximum membrane thickness - minimum membrane thickness) ÷ average membrane thickness

[0059] The polymer film is preferably manufactured as a long strip of polymer film with a width of 300 mm or more and a length of 10 m or more, in a wound state; more preferably, it is a rolled polymer film wound to a core. When the polymer film is wound into a roll, it is easy to transport in the form of a rolled polymer film.

[0060] In order to ensure operability and productivity, it is preferable to add about 0.03 to 3% by mass of a slip material (particles) with a particle size of about 10 to 1000 nm to the polymer membrane to give it tiny bumps and depressions on the surface of the polymer membrane and ensure lubrication.

[0061] <Protective Film (First Protective Film, Second Protective Film)> The composition of the protective film is not particularly limited, but it preferably includes a substrate and an adhesive layer disposed on the substrate. The protective film may have other layers besides the substrate and the adhesive layer. However, the adhesive layer is preferably laminated in a manner that brings it into contact with the heat-resistant polymer film. Therefore, the adhesive layer is preferably located on the outermost surface of the protective film.

[0062] <Substrate> The substrate serves as the strength matrix for the protective film.

[0063] The substrate is not particularly limited, but it is preferably 0.01 GPa or more at 25°C, more preferably 1 GPa or more, and even more preferably 2 GPa or more. When the tensile modulus of the substrate at 25°C is 0.3 GPa or more, the surface of the heat-resistant polymer film can be adequately protected. Furthermore, from the viewpoint that the protective film on the heat-resistant polymer film can be rolled up when peeled off, the tensile modulus of the substrate at 25°C can be, for example, set to 10 GPa or less, 5 GPa or less, etc. In this specification, the tensile modulus of the substrate at 25°C is the value measured using a tensile testing machine (Shimadzu Corporation, Autograph(R), model AG-5000A) with a tensile speed of 50 mm / min and a chuck spacing of 40 mm, by cutting the substrate into short strips of 100 mm × 10 mm as test pieces.

[0064] Examples of materials that can be used as the substrate include: polyolefin resins such as polyethylene and polypropylene; polyamide resins such as nylon 6 and nylon 66; and polyester resins such as polyethylene terephthalate, polyethylene terephthalate, polyethylene terephthalate, polyethylene terephthalate, and polyethylene terephthalate. Mixing these resins will not affect the quality of the substrate. The polyester resin can be a copolymer component, for example, a polyester resin copolymerized with diethylene glycol, neopentyl glycol, polyalkylene glycol, or dicarboxylic acid components such as adipic acid, sebacic acid, phthalic acid, isophthalic acid, and 2,6-naphthalic acid. From the viewpoints of mechanical strength, chemical resistance, and heat resistance, polyester resin is preferred.

[0065] Among the polyester resins, polyethylene terephthalate is the most preferred, considering both physical properties and cost.

[0066] The substrate is preferably biaxially oriented. Biaxial oriented stretching can improve its chemical resistance, heat resistance, mechanical strength, etc.

[0067] The substrate can be a single layer or multiple layers.

[0068] The substrate may contain various additives in the resin as needed. Examples of such additives include: antioxidants, lightfasts, gelling agents, organic wetting agents, ultraviolet absorbers, and surfactants.

[0069] The substrate can be transparent or colored. There are no particular limitations on the method of coloring the substrate; it can be colored by containing pigments or dyes. For example, it is preferable to use a white film made by mixing in white pigments such as titanium dioxide, which improves visibility.

[0070] To ensure the operability and productivity of the substrate, it is preferable to add about 0.03 to 3% by mass of a slip material (particles) with a particle size of about 10 to 1000 nm to the substrate to impart minute irregularities on the surface of the substrate and ensure lubricity.

[0071] The thickness of the substrate is not particularly limited; for example, its thickness can be arbitrarily determined according to the specifications used in the range of 12 to 500 μm. More preferably, the thickness of the substrate is 350 μm or less. A thickness of 350 μm or less can suppress the decrease in productivity and operability. Furthermore, a thickness of 25 μm to 50 μm is more preferably preferred. A thickness of 25 μm or more can reduce insufficient mechanical strength of the substrate and prevent cracking during peeling.

[0072] The substrate can be formed into a film using existing and well-known film-forming methods. Examples of such film-forming methods include: calendering, casting in organic solvents, blow extrusion in a closed system, T-die extrusion, co-extrusion, and dry lamination.

[0073] <Adhesive layer> The adhesive layer typically has a lower elastic modulus (e.g., a tensile modulus that is two or more digits lower than that of the substrate or the heat-resistant polymer film) compared to the substrate or the heat-resistant polymer film.

[0074] As the adhesive layer, known resins such as acrylic, silicone, rubber, polyester, and urethane resins can be used, and there is no particular limitation. From an operability point of view, acrylic resins and silicone resins are preferred.

[0075] The acrylic resin can be prepared by polymerizing monomers such as alkyl methacrylates. Specific examples of the monomers include: methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, isooctyl methacrylate, lauryl methacrylate, octadecyl methacrylate, and other alkyl methacrylate compounds. Multiple of these can be copolymerized as needed.

[0076] The adhesive layer is typically applied to the entire surface of the substrate. However, this is not a limitation in this invention, and there may be areas on the surface of the substrate where no adhesive layer is applied. For example, the area near both ends of the substrate surface in the width direction may also be configured without an adhesive layer.

[0077] The thickness of the adhesive layer is not particularly limited, but is usually 3 to 200 μm, preferably 5 to 30 μm.

[0078] The adhesive layer is obtained by coating an adhesive composition solution onto the substrate to form a coating film, followed by drying the coating film under predetermined conditions. The coating method is not particularly limited, and examples include roller coating, screen coating, and gravure coating. Furthermore, the drying conditions can be, for example, a drying temperature between 80 and 150°C and a drying time between 0.5 and 5 minutes. Furthermore, after coating the spacer with the adhesive composition to form a coating film, the coating film can be dried under the aforementioned drying conditions to form an adhesive layer. Then, the adhesive layer and the spacer are bonded together on the substrate. Based on the above, a protective film can be obtained.

[0079] <Other layers> The protective film may also have layers other than the substrate and the adhesive layer. For example, the protective film may also have an oligomer adhesive layer, an antistatic layer, etc. A release layer may be provided on the side of the substrate opposite to the side where the adhesive layer is provided. When the release layer is provided, for example, the protective film can be rolled into a roll before bonding the heat-resistant polymer film. In general, even when the protective film is rolled into a roll, since the adhesive layer does not directly contact the back side of the substrate but contacts the release layer, the adhesive layer can be prevented from adhering (transferring) to the back side of the substrate.

[0080] The release layer preferably contains one or more main components selected from silicone resins and fluoropolymers. The silicone resin used as a release agent can generally be any silicone resin commonly used in the field, as described in publications such as the "Silicone Materials Handbook" (Toray Dow Corning, 1993.8). Thermosetting or ionizing radiation-cured silicone resins (referring to resins and resin compositions) are typically used. For example, condensation-reaction and addition-reaction silicone resins can be used as thermosetting silicone resins, and ultraviolet or electron beam-cured silicone resins can be used as ionizing radiation-cured silicone resins. The release layer can be formed by coating these onto the substrate and then drying or curing them.

[0081] The first protective film and the second protective film can have the same structure or different structures.

[0082] After forming through holes 13 on the heat-resistant polymer film 12, the first protective film 14 is peeled off. It should be noted that if the first protective film is not attached to the first side of the heat-resistant polymer film when forming the through hole, this step is not required.

[0083] <Process B> Next, as Figure 3 As shown, the release film 18 is attached to the first surface 12a of the heat-resistant polymer film 12, which has formed through holes 13.

[0084] <The release film> The release film may have the same configuration as described in the section on the protective films (the first protective film and the second protective film). The specific configuration of the release film may be the same as that of the protective films (the first protective film and the second protective film), or it may have a different configuration.

[0085] <Process C> Next, as Figure 4 As shown, a metal layer 20 is formed on the heat-resistant polymer film 12 on the second surface 12b side of the heat-resistant polymer film 12 with the through hole 13 already formed, and on the release film 18 inside the through hole 13. At this time, a metal layer 20 is also formed on the inner wall inside the through hole 13.

[0086] The metal layer 20 can be formed using existing known methods. For example, the metal layer 20 can be formed on the heat-resistant polymer film 12 and on the release film 18 within the through hole 13 by sputtering or electroplating.

[0087] There are no particular limitations on the metals constituting the metal layer 20, but examples include: copper, gold, silver, platinum, lead, tin, nickel, cobalt, indium, rhodium, chromium, tungsten, ruthenium, and other elemental metals or alloys composed of two or more of them.

[0088] The thickness of the metal layer 20 on the heat-resistant polymer film 12 is not particularly limited, and can be appropriately set within the range of 20 to 20000 nm.

[0089] The metal layer 20 on the heat-resistant polymer film 12 and the metal layer 20 on the through hole 13 (on the release film 18) can be on the same plane, or they can be like... Figure 4 The diagram shows steps.

[0090] By performing step C, a circuit board precursor 30 with a release film can be obtained, which has a release film 18, a heat-resistant polymer film 12 with through holes 13, and a metal layer 20. The heat-resistant polymer film 12 of the circuit board precursor 30 with release film is disposed on the release film 18. In addition, the metal layer 20 of the circuit board precursor 30 with release film is disposed on the heat-resistant polymer film 12 and on the release film 18 within the through hole 13. In the circuit board precursor 30 with a release film, the heat-resistant polymer film 12 can be easily peeled off from the release film 18 because the release film 18 is easy to peel off. Furthermore, as described later, if the heat-resistant polymer film 12 is peeled off from the release film 18 and the metal layer 20 on the heat-resistant polymer film 12 is patterned after being attached to the inorganic substrate 40, less heat is experienced when the metal layer 20 is in contact with the release film 18. As a result, adhesion between the metal layer 20 and the release film 18 can be suppressed. It should be noted that in this embodiment, the illustrations focus on the case where the entire heat-resistant polymer film 12 is disposed on the release film 18, but the present invention is not limited to this example. In the present invention, "heat-resistant polymer film disposed on the release film" includes the case where at least a portion of the heat-resistant polymer film is disposed on the release film. For example, even if there are other layers between the heat-resistant polymer film and the release film, this is also included in "heat-resistant polymer film disposed on the release film".

[0091] <Process D> After process C, as Figure 5 As shown, the release film 18 is peeled off from the heat-resistant polymer film 12.

[0092] There is no particular limitation on the method for peeling the release film 18 from the heat-resistant polymer film 12, but methods such as using tweezers to roll it up from one end, having adhesive tape adhere to one side of the release film 18 and then rolling it up from the tape portion, or vacuum adsorbing one side of the release film 18 and then rolling that portion up, are all acceptable.

[0093] <Process E> Furthermore, in the circuit board manufacturing method of this embodiment, in addition to the steps A to D, an inorganic substrate 40 having a silane coupling agent layer 42 is prepared.

[0094] <Inorganic substrate> As the inorganic substrate, any plate-shaped material that can be used as a substrate made of inorganic materials can be used. Examples include: plate-shaped materials mainly composed of glass plates, ceramic plates, semiconductor wafers, metals, etc.; plate-shaped materials that are composites of these glass plates, ceramic plates, semiconductor wafers, and metals and are stacked together; plate-shaped materials in which these materials are dispersed; and plate-shaped materials containing these materials and fibers.

[0095] The glass plates include quartz glass, high-silica glass (96% silica), soda-lime glass, lead glass, aluminoborosilicate glass, borosilicate glass (Pyrex), borosilicate glass (alkali-free), borosilicate glass (micro-plates), aluminosilicate glass, etc. Among these, glass plates with a desired coefficient of linear expansion of 5 ppm / K or less are preferably commercially available products, such as Corning Gorilla Glass's "corning 7059", "corning 1737", and "EAGLE", Asahi Glass's "AN100", Nippon Electric Glass's "OA10", and SCHOTT's "AF32", etc.

[0096] The semiconductor wafer is not particularly limited, but examples include: silicon wafers, germanium wafers, silicon-germanium wafers, gallium-arsenic wafers, aluminum-gallium-indium wafers, nitrogen-phosphorus-arsenic-antimony wafers, SiC wafers, InP (indium phosphorus), InGaAs, GaInNAs, LT wafers, LN wafers, ZnO (zinc oxide), CdTe (cadmium telluride), and ZnSe (zinc selenide). Silicon wafers are preferred, and mirror-polished silicon wafers of 8 inches or larger are particularly preferred.

[0097] The metal can be a single-element metal containing W, Mo, Pt, Fe, Ni, or Au, or an alloy of nickel-chromium-iron heat-resistant and corrosion-resistant alloys such as Inconel, Monel, Nimonic, carbon-copper, Fe-Ni Invar alloy, and super Invar alloy. Furthermore, these metals also include multilayer metal plates with additional metal or ceramic layers. In this case, if the coefficient of linear expansion (CTE) of the composite layer is low, Cu, Al, etc., can be used as the main metal layer. The metal used as the additional metal layer is not particularly limited as long as it possesses properties such as enhanced adhesion to the polymer film, non-diffusion, chemical resistance, and good heat resistance; suitable examples preferably include Cr, Ni, TiN, and Cu containing Mo.

[0098] The planar portion of the inorganic substrate is expected to be sufficiently flat. Specifically, the surface roughness PV value is 50 nm or less, more preferably 20 nm or less, and even more preferably 5 nm or less. With a rougher surface, the peel strength between the polymer film and the inorganic substrate may be insufficient. The thickness of the inorganic substrate is not particularly limited, but from an operational point of view, a thickness of 10 mm or less is preferred, more preferably 3 mm or less, and even more preferably 1.3 mm or less. There is no particular limitation on the lower limit of the thickness, but it is preferably 0.07 mm or more, more preferably 0.15 mm or more, and even more preferably 0.3 mm or more.

[0099] <Silane Coupling Agent Layer> The silane coupling agent layer is sandwiched between the inorganic substrate and the polymer film in a physical or chemical manner, which enhances the adhesion between the two.

[0100] The silane coupling agent is not particularly limited, but preferably contains an amino group. Preferred examples of silane coupling agents include: N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butenyl)propylamine, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane. 3-glycidyl etheroxypropyltrimethoxysilane, 3-glycidyl etheroxypropylmethyldiethoxysilane, 3-glycidyl etheroxypropyltriethoxysilane, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidyl etheroxypropyltrimethoxysilane, 3-glycidyl etheroxypropylmethyldiethoxysilane, 3-glycidyl etheroxypropyltriethoxysilane Alkane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-(vinylbenzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane hydrochloride, 3-ureapropyltrimethoxysilane Ethoxysilane, 3-chloropropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mercaptopropyltrimethoxysilane, bis(triethoxysilylpropyl)tetrasulfide, 3-isocyanatepropyltriethoxysilane, tris(3-trimethoxysilylpropyl)isocyanurate, chloromethylphenylethyltrimethoxysilane, chloromethyltrimethoxysilane, aminophenyltrimethoxysilane, aminophenylethyltrimethoxysilane, aminophenylaminomethylphenylethyltrimethoxysilane, etc.

[0101] In addition to the above, the following silane coupling agents may be used as the silane coupling agent: n-propyltrimethoxysilane, butyltrichlorosilane, 2-cyanoethyltriethoxysilane, cyclohexyltrichlorosilane, decyltrichlorosilane, diacetoxydimethylsilane, diethoxydimethylsilane, dimethoxydimethylsilane, dimethoxydiphenylsilane, dimethoxymethylphenylsilane, dodecyltrichlorosilane, dodecyltrimethoxysilane, ethyltrichlorosilane, hexyltrimethoxysilane, octadecyltriethoxysilane, octadecyltrimethoxysilane, n-octyltrichlorosilane, n-octyltriethoxysilane, n-octyltrimethoxysilane, triethoxyethylsilane, triethoxymethylsilane, trimethoxymethylsilane, trimethoxy... Phenylsilane, pentyltriethoxysilane, pentyltrichlorosilane, triacetoxymethylsilane, trichlorohexylsilane, trichloromethylsilane, trichlorooctadecylsilane, trichloropropylsilane, trichlorotetradecylsilane, trimethoxypropylsilane, allyltrichlorosilane, allyltriethoxysilane, allyltrimethoxysilane, diethoxymethylvinylsilane, diethoxymethylvinylsilane, trichlorovinylsilane, triethoxyvinylsilane, vinyltri(2-methoxyethoxy)silane, trichloro-2-cyanoethylsilane, diethoxy(3-glycidoxypropyl)methylsilane, 3-glycidoxypropyl(dimethoxy)methylsilane, 3-glycidoxypropyltrimethoxysilane, etc.

[0102] Among the silane coupling agents, those having one silicon atom per molecule are particularly preferred. Examples include: N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butenyl)propylamine, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidyl etheroxypropyltrimethoxysilane, 3-glycidyl etheroxypropylmethyldiethoxysilane, 3-glycidyl etheroxypropyltriethoxysilane, aminophenyltrimethoxysilane, aminophenylethyltrimethoxysilane, and aminophenylaminomethylphenylethyltrimethoxysilane. In particular, when high heat resistance is required, silane coupling agents using aromatic groups to link Si and amino groups are expected to be used.

[0103] A coupling layer other than the silane coupling agent layer can be disposed on the inorganic substrate. In addition to the above, the following coupling agents may be used as coupling agents for forming the coupling layer: 1-mercapto-2-propanol, methyl 3-mercaptopropionate, 3-mercapto-2-butanol, butyl 3-mercaptopropionate, 3-(dimethoxymethylsilyl)-1-propanethiol, 4-(6-mercaptohexoxy)benzyl alcohol, 11-amino-1-undecylthiol, 11-mercaptoundecylphosphonic acid, 11-mercaptoundecyltrifluoroacetic acid, 2,2'-(1,2-ethylenedioxydiethyl)diethylthiol, 11-mercaptoundecyl... Tri(ethylene glycol), (1-mercapto-11-undecyl)tetra(ethylene glycol), 1-(methylcarboxyl)-11-undecyl)hexa(ethylene glycol), hydroxyundecyl disulfide, carboxyundecyl disulfide, hydroxyhexadecyl disulfide, carboxyhexadecyl disulfide, tetra(2-ethylhexyloxy)titanium, dioctyloxybis(octyl glycol ester) titanium, tributoxyacetylacetone zirconium, monobutoxyacetylacetone bis(ethyl acetoacetate) zirconium, tributoxymonostearate zirconium, (octadecyl-9-enyl) Acetoacetate-01',03) dipropane-2-ol aluminum, 3-glycidoxypropyltrimethoxysilane, 2,3-butanedithiol, 1-butanethiol, 2-butanethiol, cyclohexanethiol, cyclopentanethiol, 1-decanethiol, 1-dodecanethiol, 2-ethylhexyl 3-mercaptopropionate, ethyl 3-mercaptopropionate, 1-heptanethiol, 1-hexadecanethiol, hexanethiol, isopentylthiol, isobutylthiol, 3-mercaptopropionic acid, 3-mercaptopropionate-3-methoxybutyl ester, 2-methyl-1-butanethiol Alcohols, 1-octadecylthiol, 1-octanethiol, 1-pentadecanthiol, 1-pentanethiol, 1-propanethiol, 1-tetradecylthiol, 1-undecylthiol, 1-(12-mercaptododecyl)imidazol, 1-(11-mercaptoundecyl)imidazol, 1-(10-mercaptodecyl)imidazol, 1-(16-mercaptohexadecyl)imidazol, 1-(17-mercaptoheptadecyl)imidazol, 1-(15-mercapto)dodecanoic acid, 1-(11-mercapto)undecanoic acid, 1-(10-mercapto)decanoic acid, etc.

[0104] As a coating method for silane coupling agents (method for forming silane coupling agent layers), methods such as coating silane coupling agent solutions onto inorganic substrates and vapor deposition can be used.

[0105] As a method for coating a silane coupling agent solution, the solution of the silane coupling agent can be diluted with solvents such as alcohols, and existing known solution coating methods such as spin coating, curtain coating, dip coating, slot die coating, gravure coating, bar coating, comma coating, coater coating, screen printing, and spray coating can be appropriately used.

[0106] One method for forming a silane coupling agent layer by vapor deposition is to expose the aforementioned inorganic substrate to the vapor of a silane coupling agent, that is, to substantially expose it to a gaseous state of silane coupling agent for formation. The vapor of the silane coupling agent can be obtained by heating the liquid silane coupling agent to approximately 40°C to its boiling point. The boiling point of the silane coupling agent varies depending on its chemical structure, but is generally in the range of 100–250°C. The heating environment for silane coupling agents can be under pressure, atmospheric pressure, or reduced pressure, but atmospheric pressure or reduced pressure is preferred when promoting the vaporization of silane coupling agents. Since most silane coupling agents are flammable liquids, vaporization is preferably carried out in a closed container, preferably after replacing the gas in the container with an inactive gas. There is no particular limitation on the time for which the inorganic substrate is exposed to the silane coupling agent, but it is preferably within 20 hours, more preferably within 60 minutes, even more preferably within 15 minutes, and most preferably within 1 minute. The temperature of the inorganic substrate during exposure to the silane coupling agent is preferably controlled at a suitable temperature between -50°C and 200°C, depending on the type of silane coupling agent and the determined thickness of the silane coupling agent layer.

[0107] The thickness of the silane coupling agent layer 42 is not particularly limited, as long as it is sufficient to cover the entire surface of the inorganic substrate.

[0108] <Process F> After the aforementioned process D, as Figure 6 As shown, on the first surface 12a after the release film 18 of the heat-resistant polymer film 12 has been peeled off, the inorganic substrate 40 is attached with the silane coupling agent layer 42 as the bonding surface. Specifically, the first surface 12a of the heat-resistant polymer film 12 and the inorganic substrate 40 are bonded together by pressure and heat. The inorganic substrate 40 is a substrate prepared in step E.

[0109] Pressure heating treatment can be performed, for example, by pressing, laminating, or roller laminating while heating in an atmospheric atmosphere or vacuum. Alternatively, pressure heating can be applied while the bag is placed inside a flexible bag. From the viewpoint of improving productivity and reducing processing costs due to high productivity, pressing or roller laminating in an atmospheric atmosphere is preferred, and methods using rollers (such as roller laminating) are particularly preferred.

[0110] The pressure used for the pressurized heat treatment is preferably 1 MPa to 20 MPa, more preferably 3 MPa to 10 MPa. A pressure of 20 MPa or less can suppress damage to the inorganic substrate. Furthermore, a pressure of 1 MPa or more can prevent the formation of incomplete adhesion or gaps in the bond. The temperature used for the pressurized heat treatment is preferably 150°C to 400°C, more preferably 250°C to 350°C. Furthermore, the pressurized heating treatment can be carried out in an atmospheric pressure atmosphere as described above, but in order to obtain a fully stable peel strength, it is also preferable to carry it out under vacuum. For this vacuum level, the vacuum level obtained by a typical oil rotary pump is sufficient, as long as it is below 10 Torr. As a device that can be used for pressurized heating treatment, for example, when pressing in a vacuum, the "11FD" manufactured by Imoto Manufacturing can be used. For vacuum lamination, such as a roller laminator in a vacuum or a film laminator that applies pressure to the entire glass surface by passing a thin rubber membrane through a vacuum after vacuuming, the "MVLP" manufactured by Meiki Manufacturing can be used.

[0111] The pressurized heating process can be divided into a pressurization step and a heating step. First, the polymer film and inorganic substrate are pressurized at a relatively low temperature (e.g., below 120°C, more preferably below 95°C) to ensure close adhesion. Then, heating is performed at a low pressure (preferably below 0.2 MPa, more preferably below 0.1 MPa) or normal pressure and a relatively high temperature (e.g., above 120°C, more preferably 120–250°C, and even more preferably 150–230°C) to promote a chemical reaction at the close-adhesion interface, thus laminating the polymer film and inorganic substrate.

[0112] By performing the above process F, a circuit board precursor 50 with an inorganic substrate can be obtained, which has an inorganic substrate 40, a silane coupling agent layer 42, a heat-resistant polymer film 12 with through holes 13, and a metal layer 20. A silane coupling agent layer 42 of the circuit board precursor 50 with an inorganic substrate is disposed on the inorganic substrate 40. Furthermore, a heat-resistant polymer film 12 of the circuit board precursor 50 with an inorganic substrate is disposed on the silane coupling agent layer 42. Additionally, a metal layer 20 of the circuit board precursor 50 with an inorganic substrate is disposed on the heat-resistant polymer film 12 and on the silane coupling agent layer 42 within the through-hole 13. In the circuit board precursor 50 with an inorganic substrate, the metal layer 20 within the through-hole 13 adheres to the silane coupling agent layer 42 with only moderate adhesion, and subsequently, even under heat treatment, it cannot be firmly fixed to the inorganic substrate 40. Furthermore, the silane coupling agent layer 42 and the heat-resistant polymer film 12 also adhere with only moderate adhesion, and subsequently, even under heat treatment, they cannot be firmly fixed to the inorganic substrate 40. Therefore, after the patterning process G of the metal layer 20 described later, the inorganic substrate 40 with the silane coupling agent layer 42 can be easily peeled off from the heat-resistant polymer film 12 by peeling or the like. Overall, with the silane coupling agent layer 42 and the heat-resistant polymer film 12 as the interface, the inorganic substrate 40 can be easily peeled off from the heat-resistant polymer film 12. Since the inorganic substrate 40 can be peeled off from the heat-resistant polymer film 12 by means of tearing, the peeling agent used to peel off the inorganic substrate 40 will not adhere to the patterned metal layer 20, and there will be no plasma irradiation. As a result, the circuit board (patterned metal layer) formed on the inorganic substrate 40 can be peeled off from the inorganic substrate with minimal damage.

[0113] <Process G> After the aforementioned process F, as Figure 7 As shown, the metal layer 20 is patterned. There is no particular limitation on the method for patterning the metal layer 20; existing known techniques can be used. For example, the patterned metal layer 20 (also called wiring layer 21) can be obtained by etching the metal layer 20 into a predetermined pattern (wiring pattern) using existing known etching techniques.

[0114] Subsequently, a second wiring layer may be formed on wiring layer 21 as needed. The following explanation addresses the case of forming a second wiring layer.

[0115] <Process G-1> After the aforementioned process G, such as Figure 8 As shown, an adhesive is applied to the entire wiring layer 21 and cured to form an adhesive layer 44 (step G-1). The adhesive can be any known adhesive (e.g., an adhesive containing a thermosetting resin, an adhesive containing a UV-curable resin, etc.). Preferably, the adhesive is formed from a material that, upon curing, becomes an insulating adhesive layer.

[0116] <Process G-2> After process G-1, as Figure 9 As shown, a second heat-resistant polymer film 46 is attached to the adhesive layer 44. During attachment, heating and pressurization can make the surface of the adhesive layer 44 flatter. It should be noted that the order of the steps G-1 and G-2 is not particularly limited. For example, an adhesive can be applied to the entire wiring layer 21, and before it cures, the second heat-resistant polymer film 46 can be attached, followed by the curing of the adhesive layer.

[0117] The second heat-resistant polymer film 46 may have the same composition as described in the entry for heat-resistant polymer films. The heat-resistant polymer film 12 and the second heat-resistant polymer film 46 may have the same composition or different compositions.

[0118] <Process G-3> Following step G-2, a through-hole is formed connecting the second heat-resistant polymer film 46 and the adhesive layer 44. Electroplating is applied to the inner wall of the through-hole to form a via 48. Further, a second wiring layer 49 is formed on the second heat-resistant polymer film 46. Thus, a circuit with two wiring layers (see reference) is obtained, connecting the wiring layer 21 and the second wiring layer 49. Figure 10 The formation of the through hole, the through hole 48, and the wiring layer 49 can be achieved using existing and known techniques. It should be noted that, furthermore, the same process can be repeated to form other wiring layers on the second wiring layer 49, thus creating a multi-layered circuit (see reference). Figure 10 ). Furthermore, semiconductor chips can be stacked and connected to the topmost wiring layer (not shown).

[0119] It should be noted that, depending on the needs, a photosensitive film can also be used as the second heat-resistant polymer film 46 for exposure and development to pattern the second heat-resistant polymer film 46.

[0120] <Process H> Following step G, further, as needed, after steps G-1 to G-3, the inorganic substrate 40 is peeled off from the heat-resistant polymer film 12 (see reference). Figure 11 The circuit board 60 can be obtained through the above process.

[0121] There are no particular limitations on the method for peeling the inorganic substrate 40 from the heat-resistant polymer film 12. Existing methods such as laser lift-off, which uses a wavelength that can pass through the inorganic substrate and is absorbed at the heat-resistant polymer film 12, thereby concentrating the laser energy at the interface between the inorganic substrate 40 and the heat-resistant polymer film 12 for peeling, and mechanical lift-off, which peels off along an arc with a large radius of curvature, can be used. A simpler method is to use tweezers or similar tools to roll it up from one end.

[0122] According to the circuit board manufacturing method of this embodiment, in step C, a metal layer 20 is formed on a release film 18 within a through hole 13. Since the release film 18 is easily peeled off, the heat-resistant polymer film 12 can also be easily peeled off from the release film 18 after the metal layer 20 is formed. Furthermore, after the metal layer 20 is formed, the heat-resistant polymer film 12 is peeled off from the release film 18 and patterned onto the inorganic substrate 40. Therefore, the heat experience experienced when the metal layer 20 and the release film 18 are in contact is reduced. As a result, the adhesion between the metal layer 20 and the release film 18 is suppressed. Furthermore, in step F, using the silane coupling agent layer 42 as the bonding surface, the heat-resistant polymer film 12 with the metal layer 20, peeled from the release film 18, is attached to the inorganic substrate 40. The metal layer 20 peeled from the release film 18 (the metal layer 20 exposed from the through hole 13) is temporarily attached to the silane coupling agent layer 42 with only moderate adhesion, and subsequently, even under heat exposure, it cannot be firmly fixed to the inorganic substrate 40. Furthermore, the silane coupling agent layer 42 and the heat-resistant polymer film 12 are only attached with moderate adhesion, and subsequently, even under heat exposure, they will not be firmly fixed to the inorganic substrate 40. Therefore, after step G, in which the metal layer 20 is patterned, the inorganic substrate 40 with the silane coupling agent layer 42 can be easily peeled off from the heat-resistant polymer film 12 by means of peeling or the like. In general, the inorganic substrate 40 can be easily peeled off from the heat-resistant polymer film 12 using the silane coupling agent layer 42 and the heat-resistant polymer film 12 as the interface. Since the inorganic substrate 40 can be peeled off from the heat-resistant polymer film 12 by tearing or the like, the adhesion of the peeling agent used to peel off the inorganic substrate to the patterned metal layer 20 (wiring layer 21) and the irradiation with plasma are avoided. As a result, the circuit board 60 (patterned metal layer 20, etc.) formed on the inorganic substrate 40 can be peeled off from the inorganic substrate 40 with minimal damage.

[0123] The embodiments of the present invention have been described above, but the present invention is not limited to the examples described above. Appropriate design changes can be made within the scope of the present invention.

Claims

1. A method for manufacturing a circuit board, characterized in that, contain: Process A: Forming through-holes in a heat-resistant polymer film Step B involves attaching a release film to the first side of the heat-resistant polymer film, which has already formed through-holes. Step C: Forming a metal layer on the heat-resistant polymer film on one side of the second surface of the heat-resistant polymer film with through holes and on the release film within the through holes. Step D, following step C, involves peeling the release film from the heat-resistant polymer film. Step E: Preparing an inorganic substrate with a silane coupling agent layer Following step D, step F involves attaching the inorganic substrate to the heat-resistant polymer film, after the release film has been peeled off, using the silane coupling agent layer as the bonding surface. Following step F, step G involves patterning the metal layer. Step H is the step after step G in which the inorganic substrate is peeled off from the heat-resistant polymer film.

2. The method for manufacturing a circuit board according to claim 1, characterized in that, The heat-resistant polymer film is a polyimide film.

3. The method for manufacturing a circuit board according to claim 1 or 2, characterized in that, The inorganic substrate is a glass plate, a ceramic plate, a semiconductor wafer, or a composite formed by stacking two or more of the aforementioned substrates.

Images