KR20240035388A - Method for manufacturing a circuit board, circuit board precursor with release film, and circuit board precursor with inorganic substrate - Google Patents

Abstract

Process A of forming a through hole in the heat-resistant polymer film, Process B of adhering a release film to the first side of the heat-resistant polymer film on which the through hole is formed, on the heat-resistant polymer film from the second side of the heat-resistant polymer film on which the through hole is formed, and Step C of forming a metal layer on the release film in the through hole, after step C, step D of peeling the release film from the heat-resistant polymer film, step E of preparing an inorganic substrate with a silane coupling agent layer, after step D, heat-resistant polymer Process F of bonding an inorganic substrate to the first side of the film after peeling off the release film using the silane coupling agent layer as a bonding surface. After process F, process G of patterning the metal layer, and after process G, the inorganic substrate is bonded to the heat-resistant polymer. A method of manufacturing a circuit board including step H of peeling from the film.

Description

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

The present 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.

Recently, with the high integration of semiconductor devices, there is a demand for higher density of circuit boards. Therefore, the electrodes of the IC chip become high-density, and the circuit board as the redistribution layer requires a circuit with fine parts, for example, a fan-out panel level package. In addition, the high-density circuit board is used as a wiring layer for mini LEDs (extremely small LEDs disposed immediately below the liquid crystals that make up the liquid crystal display device).

As a method of manufacturing a circuit board, a method is known in which a circuit layer having an insulating layer and a pattern wiring layer is formed on a dummy board using a thin film forming technique or the like, and then the dummy board is peeled off.

For example, in Patent Document 1, a dummy substrate is used as a dummy substrate in which a carrier layer (base material) containing metal foil, a peeling layer with a weak peeling strength, a copper plating layer, and a peeling protective layer containing an insulating resin are sequentially laminated. It is disclosed that a dummy substrate is removed from the thin film circuit body after forming a thin film circuit body (circuit layer) thereon.

[Patent Document 1] Japanese Patent Publication No. 2004-311912

In the circuit board manufacturing method disclosed in Patent Document 1, in order to remove the dummy board from the thin film circuit body, first, the carrier layer and the peeling layer are peeled off while the copper plating layer and the peeling protective layer remain on the thin film circuit body side. . Thereafter, the copper plating layer is removed by a wet etching method using a stripping chemical such as sulfuric acid, and the peeling protective layer is removed by a dry etching method using oxygen plasma or the like (in particular, paragraph [0061] of Patent Document 1) , see paragraph [0062]).

In general, when a circuit board is formed directly on a carrier layer (base material) containing metal foil using a thin film forming technology, the carrier layer and the circuit board are firmly adhered, and both cannot be easily peeled off. In particular, the metal layer formed on the carrier layer is then adhered to the carrier layer more strongly by receiving heat history. For example, when patterning is performed on a metal layer formed on a carrier layer and a multi-layer patterned metal layer (wiring layer) is formed thereon, heat history is applied in multiple stages. Therefore, in Patent Document 1, the carrier layer and the thin film circuit body are separated by disposing a peeling layer, a copper plating layer, and a peeling protective layer between the carrier layer and the thin film circuit body.

However, in the circuit board manufacturing method as described above, there is a problem that damage to the thin film circuit body occurs, such as when an etchant adheres to the thin film circuit body or plasma or the like is irradiated to remove the copper plating layer or the peeling protective layer. .

The present invention was made in view of the above-described problem, and its purpose is to provide a circuit board that can be peeled from an inorganic substrate without damaging the circuit board formed on the inorganic substrate as much as possible, while also requiring fewer steps after peeling. The purpose is to provide a manufacturing method. In addition, the object is to provide a circuit board precursor with a release film and a circuit board precursor with an inorganic substrate obtained in the process of carrying out the above manufacturing method.

The present inventor conducted intensive research on the manufacturing method of circuit boards. As a result, it was found that by adopting the following configuration, the circuit board can be peeled from the inorganic substrate with as little damage as possible to the circuit board formed on the inorganic substrate, while also reducing the number of steps after peeling, and the present invention was completed. It came down to this.

That is, the present invention provides the following.

Process A of forming a through hole in a heat-resistant polymer film,

Process B of adhering a release film to the first side of the heat-resistant polymer film on which the through hole is formed,

Step C of forming a metal layer on the heat-resistant polymer film and on the release film in the through-hole from the second surface side of the heat-resistant polymer film on which the through-hole is formed,

After step C, step D of peeling the release film from the heat-resistant polymer film,

Process E of preparing an inorganic substrate having a silane coupling agent layer,

After step D, step F of bonding the inorganic substrate to the first surface of the heat-resistant polymer film after peeling off the release film, using the silane coupling agent layer as a bonding surface,

After process F, process G of patterning the metal layer and

After step G, step H of peeling the inorganic substrate from the heat-resistant polymer film

A method of manufacturing a circuit board comprising:

According to the above configuration, in step C, a metal layer is formed on the release film in the through hole. Since the release film is easy to peel, the heat-resistant polymer film can be easily peeled from the release film even after forming the metal layer. Additionally, after forming the metal layer, the heat-resistant polymer film is peeled from the release film, and patterning is performed after adhering it to the inorganic substrate. Therefore, there is little chance of receiving heat history when the metal layer and the release film are in contact. As a result, adhesion of the metal layer and the release film is suppressed.

Additionally, in step F, the heat-resistant polymer film with a metal layer peeled from the release film is bonded to an inorganic substrate using the silane coupling agent layer as a bonding surface. First, the metal layer peeled from the release film (the metal layer exposed from the through hole) is only adhered to the silane coupling agent layer with appropriate adhesion, and thereafter, it is not strongly adhered to the inorganic substrate even when subjected to heat history. In addition, the silane coupling agent layer and the heat-resistant polymer film are only adhered with appropriate adhesion, and are not strongly adhered to the inorganic substrate even when subjected to heat history thereafter. Therefore, after the step G of patterning the metal layer, the inorganic substrate with the silane coupling agent layer can be easily peeled from the heat-resistant polymer film, such as by pulling it off. That is, by using the silane coupling agent layer and the heat-resistant polymer film as an interface, the inorganic substrate can be easily peeled from the heat-resistant polymer film. Since the inorganic substrate can be peeled off from the heat-resistant polymer film by pulling it off, it is impossible for a peeling chemical solution for peeling off the inorganic substrate to adhere to the patterned metal layer or for it to be irradiated with plasma or the like. As a result, the circuit board can be peeled from the inorganic substrate with as little damage as possible to the circuit board (patterned metal layer) formed on the inorganic substrate.

Additionally, since the inorganic substrate can be peeled off from the heat-resistant polymer film by pulling it off, there are few steps that cause damage to the circuit board after peeling the inorganic substrate from the heat-resistant polymer film. For example, in Patent Document 1, after peeling the carrier layer and the thin film circuit body, it is necessary to apply an etchant or plasma irradiation to remove the copper plating layer or the peeling protective layer, but in the present invention, the inorganic substrate is peeled from the heat-resistant polymer film. Since it can be done, such processing is not necessary.

In addition, by forming a silane coupling agent layer between the inorganic substrate and the heat-resistant polymer film, the inorganic substrate and the heat-resistant polymer film are bonded with an appropriate peel strength, and the two can be easily peeled (separated), for example, Japanese Patent Publication 2011 It is disclosed in Publication No. -011455, etc.

In the above configuration, it is preferable that the heat-resistant polymer film is a polyimide film.

If the heat-resistant polymer film is a polyimide film, it has excellent heat resistance. Additionally, if the polymer film is a polyimide film, it can be suitably perforated with a laser.

In the above configuration, the inorganic substrate is preferably a glass plate, a ceramic plate, a semiconductor wafer, or a composite of two or more of these.

If the inorganic substrate is a glass plate, a ceramic plate, a semiconductor wafer, or a composite of two or more of these, the elastic modulus is high and the linear expansion coefficient is small, so dimensional stability is excellent. As a result, the dimensional accuracy of the manufactured circuit board becomes good.

Additionally, the present invention provides the following.

A release film,

A heat-resistant polymer film having a through hole,

Provided with a metal layer,

The heat-resistant polymer film is formed on the release film,

A circuit board precursor with a release film, wherein the metal layer is formed on the heat-resistant polymer film and on the release film in the through hole.

The circuit board precursor with the release film can be obtained in the process of carrying out the circuit board manufacturing method.

According to the above configuration, since the release film is easy to peel, the heat-resistant polymer film can be easily peeled from the release film. Additionally, if the heat-resistant polymer film is peeled from the release film and patterning of the metal layer on the heat-resistant polymer film is performed after adhering it to an inorganic substrate, the metal layer and the release film are less likely to experience heat history while in contact. As a result, adhesion of the metal layer and the release film can be prevented.

Additionally, the present invention provides the following.

an inorganic substrate,

A silane coupling agent layer,

A heat-resistant polymer film having a through hole,

Provided with a metal layer,

The silane coupling agent layer is formed on the inorganic substrate,

The heat-resistant polymer film is formed on the silane coupling agent layer,

The circuit board precursor with an inorganic substrate, characterized in that the metal layer is formed on the heat-resistant polymer film and on the silane coupling agent layer in the through hole.

The circuit board precursor with the inorganic substrate can be obtained during the process of carrying out the circuit board manufacturing method.

According to the above configuration, the metal layer in the through hole is simply adhered to the silane coupling agent layer with an appropriate adhesion force, and thereafter, it is not firmly adhered to the inorganic substrate even when subjected to heat history. Additionally, the silane coupling agent layer and the heat-resistant polymer film are only adhered with appropriate adhesion, and are not strongly adhered to the inorganic substrate even when subjected to heat history thereafter. Therefore, after the step G of patterning the metal layer, the inorganic substrate with the silane coupling agent layer can be easily peeled from the heat-resistant polymer film, such as by pulling it off. That is, by using the silane coupling agent layer and the heat-resistant polymer film as an interface, the inorganic substrate can be easily peeled from the heat-resistant polymer film. Since the inorganic substrate can be peeled off from the heat-resistant polymer film by pulling it off, it is impossible for a peeling chemical solution for peeling off the inorganic substrate to adhere to the patterned metal layer or for it to be irradiated with plasma or the like. As a result, the circuit board can be peeled from the inorganic substrate with as little damage as possible to the circuit board (patterned metal layer) formed on the inorganic substrate.

According to the present invention, it is possible to provide a method of manufacturing a circuit board that can peel a circuit board from an inorganic substrate without damaging the circuit board formed on the inorganic substrate as much as possible. In addition, a circuit board precursor with a release film and a circuit board precursor with an inorganic substrate obtained in the process of carrying out the above manufacturing method can be provided.

1 is a cross-sectional schematic diagram for explaining a method of manufacturing a circuit board according to this embodiment.
Figure 2 is a cross-sectional schematic diagram for explaining the manufacturing method of the circuit board according to this embodiment.
Figure 3 is a cross-sectional schematic diagram for explaining the manufacturing method of the circuit board according to this embodiment.
Figure 4 is a cross-sectional schematic diagram for explaining the manufacturing method of the circuit board according to this embodiment.
Figure 5 is a cross-sectional schematic diagram for explaining the manufacturing method of the circuit board according to this embodiment.
Figure 6 is a cross-sectional schematic diagram for explaining the manufacturing method of the circuit board according to this embodiment.
Figure 7 is a cross-sectional schematic diagram for explaining the manufacturing method of the circuit board according to this embodiment.
Figure 8 is a cross-sectional schematic diagram for explaining the manufacturing method of the circuit board according to this embodiment.
9 is a cross-sectional schematic diagram for explaining the manufacturing method of the circuit board according to this embodiment.
Figure 10 is a cross-sectional schematic diagram for explaining the manufacturing method of the circuit board according to this embodiment.
Figure 11 is a cross-sectional schematic diagram for explaining the manufacturing method of the circuit board according to this embodiment.

Hereinafter, embodiments of the present invention will be described. Below, a method for manufacturing a circuit board will be described, and among these, a circuit board precursor with a release film and a circuit board precursor with an inorganic substrate will also be described.

[Circuit board manufacturing method]

The method for manufacturing a circuit board according to this embodiment is:

Process A of forming a through hole in a heat-resistant polymer film,

Process B of adhering a release film to the first side of the heat-resistant polymer film on which the through hole is formed,

Step C of forming a metal layer on the heat-resistant polymer film and on the release film in the through-hole from the second surface side of the heat-resistant polymer film on which the through-hole is formed,

After step C, step D of peeling the release film from the heat-resistant polymer film,

Process E of preparing an inorganic substrate having a silane coupling agent layer,

After step D, step F of bonding the inorganic substrate to the first surface of the heat-resistant polymer film after peeling off the release film, using the silane coupling agent layer as a bonding surface,

After process F, process G of patterning the metal layer and

After step G, step H of peeling the inorganic substrate from the heat-resistant polymer film

Includes.

<Process A>

In the circuit board manufacturing method according to this embodiment, a through hole is first formed in the heat-resistant polymer film. The heat-resistant polymer film may be prepared with a protective film adhered to both sides, may be prepared with a protective film adhered to only one side, or may be prepared with nothing adhered to both sides.

When preparing a heat-resistant polymer film with a protective film adhered to both sides, the through hole may be formed with the protective film adhered to both sides, or may be formed after peeling the protective film on both sides, or may be formed on one side. It may be formed after peeling off only the protective film.

When preparing a heat-resistant polymer film with a protective film adhered to only one side, the through hole may be formed with the protective film on one side adhered, or may be formed after peeling off only the protective film on one side. good night.

In the embodiment described below, a case where a heat-resistant polymer film is prepared with a protective film attached to both sides, and a through hole is formed with a protective film adhered to both sides will be described.

1 to 11 are cross-sectional schematic diagrams for explaining the method of manufacturing a circuit board according to this embodiment.

As shown in FIG. 1, in the circuit board manufacturing method according to this embodiment, first, a heat-resistant polymer film 10 with a double-sided protective film is prepared. The heat-resistant polymer film 10 with a double-sided protective film includes a heat-resistant polymer film 12, a first protective film 14 adhered to the first side 12a of the heat-resistant polymer film 12, and a heat-resistant polymer film 12. ) has a second protective film 16 adhered to the second surface 12b.

Next, as shown in FIG. 2, a through hole 13 is formed in the heat-resistant polymer film 12. In this embodiment, the through hole 13 is formed in the heat-resistant polymer film 12 with protective films (first protective film 14 and second protective film 16) adhered to both sides of the heat-resistant polymer film 12. forms. Accordingly, through holes are also formed in the first protective film 14 and the second protective film 16. Additionally, an electrode for external connection is ultimately formed in the through hole 13. Accordingly, the through hole 13 is formed at a position where an electrode for external connection is to be formed.

The through hole 13 can be formed by employing a conventionally known method, for example, hole drilling using a laser. In addition, when the heat-resistant polymer film 12 is formed of a photosensitive resin, the through-hole 13 can be formed by irradiating light through a photomask on which a pattern corresponding to the through-hole 13 is formed and then developing the heat-resistant polymer film 12. You can. In this case, it is preferable to perform light irradiation and development without attaching a protective film on the side where the photomask is placed.

The shape (shape in plan view) of the through hole 13 is not particularly limited, but is preferably circular, and the diameter can be set appropriately, for example, 300 μm to 5 μm.

Hereinafter, the heat-resistant polymer film, the first protective film, and the second protective film will be described.

<Heat-resistant polymer film>

In this specification, a heat-resistant polymer has a melting point of 250°C or higher, preferably 300°C or higher, and more preferably 400°C or higher. Additionally, it is a polymer with a glass transition temperature of 200°C or higher, preferably 320°C or higher, and more preferably 380°C or higher. Hereinafter, to avoid complexity, it is also referred to simply as polymer. In this specification, the melting point and glass transition temperature are obtained by differential thermal analysis (DSC). In addition, the heat-resistant polymer film is not limited to this as long as it has practical strength through existing methods such as glass fiber reinforcement or high-concentration filler filling. In addition, when the melting point exceeds 500°C, it may be determined whether the melting point has been reached by visually observing the thermal deformation behavior when heated at the above temperature.

Examples of the heat-resistant polymer film (hereinafter also simply referred to as polymer film) include polyimide-based resins such as polyimide, polyamidoimide, polyetherimide, and fluorinated polyimide (e.g., aromatic polyimide resin, cycloaliphatic polyimide resin); copolymerized polyesters such as polyethylene, polypropylene, polyethylene terephthalate, polybutylene terephthalate, and polyethylene-2,6-naphthalate (eg, wholly aromatic polyester, semi-aromatic polyester); Copolymerized (meth)acrylates such as polymethyl methacrylate; polycarbonate; polyamide; polysulfone; polyethersulfone; polyether ketone; Cellulose acetate; cellulose nitrate; aromatic polyamide; polyvinyl chloride; polyphenol; polyarylate; polyphenylene sulfide; polyphenylene oxide; Examples include films such as polystyrene.

However, since the polymer film is assumed to be used in a process involving heat treatment of 300°C or higher, the actual applicability of the polymer films exemplified is limited. Among the above polymer films, films using so-called super engineering plastics are particularly preferred, and more specifically, aromatic polyimide film, aromatic amide film, aromatic amidimide film, aromatic benzoxazole film, aromatic benzothiazole film, and aromatic benzoate film. An imidazole film, etc. can be mentioned.

Below, a polyimide-based resin film (sometimes called a polyimide film), which is an example of the polymer film, will be described in detail. In general, a polyimide-based resin film is a green film (hereinafter referred to as a green film) made by applying a polyamic acid (polyimide precursor) solution obtained by reacting diamines and tetracarboxylic acids in a solvent to a support for producing a polyimide film and drying it. Also referred to as “polyamic acid film”), it is obtained by subjecting a green film to a high temperature heat treatment on a support for polyimide film production or in a state peeled from the support to perform a dehydration ring-closure reaction.

Application of the polyamic acid (polyimide precursor) solution can be done using conventionally known solutions such as spin coat, doctor blade, applicator, comma coater, screen printing, slit coat, reverse coat, dip coat, curtain coat, and slit die coat. Any application means may be used appropriately.

There is no particular limitation on the diamines constituting the polyamic acid, and aromatic diamines, aliphatic diamines, alicyclic diamines, etc. commonly used in polyimide synthesis can be used. Aromatic diamines are preferable from the viewpoint of heat resistance. Diamines may be used individually, or two or more types may be used together.

There is no particular limitation on the diamines, and examples include oxydianiline (bis(4-aminophenyl)ether), paraphenylenediamine (1,4-phenylenediamine), and the like.

Examples of the tetracarboxylic acids constituting the polyamic acid include aromatic tetracarboxylic acids (including their acid anhydrides), aliphatic tetracarboxylic acids (including their acid anhydrides), and alicyclic tetracarboxylic acids commonly used in polyimide synthesis. Boxylic acids (including their acid anhydrides) can be used. When these are acid anhydrides, there may be one or two anhydride structures in the molecule, but those having two anhydride structures (dianhydrides) are preferred. Tetracarboxylic acids may be used individually, or two or more types may be used in combination.

There is no particular limitation on the tetracarboxylic acid, and examples include pyromellitic dianhydride and 3,3',4,4'-biphenyltetracarboxylic dianhydride.

The polyimide film may be a transparent polyimide film.

Colorless and transparent polyimide, which is an example of the polymer film, will be described. Hereinafter, to avoid complexity, it is also simply described as transparent polyimide. In terms of transparency of transparent polyimide, it is preferable that the total light transmittance is 75% or more. More preferably, it is 80% or more, further preferably is 85% or more, even more preferably is 87% or more, and especially preferably is 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, it is preferably 98% or less, and more preferably 97% or less. The colorless and transparent polyimide in the present invention is preferably a polyimide with a total light transmittance of 75% or more.

Examples of aromatic tetracarboxylic acids for obtaining a colorless and highly transparent polyimide include 4,4'-(2,2-hexafluoroisopropylidene)diphthalic acid, 4,4'-oxydiphthalic acid, and bis(1,3). -dioxo-1,3-dihydro-2-benzofuran-5-carboxylic acid) 1,4-phenylene, bis (1,3-dioxo-1,3-dihydro-2-benzofuran- 5-yl) benzene-1,4-dicarboxylate, 4,4'-[4,4'-(3-oxo-1,3-dihydro-2-benzofuran-1,1-diyl)bis (benzene-1,4-diyloxy)]dibenzene-1,2-dicarboxylic acid, 3,3',4,4'-benzophenonetetracarboxylic acid, 4,4'-[(3- oxo-1,3-dihydro-2-benzofuran-1,1-diyl)bis(toluene-2,5-diyloxy)]dibenzene-1,2-dicarboxylic acid, 4,4'- [(3-oxo-1,3-dihydro-2-benzofuran-1,1-diyl)bis(1,4-xylene-2,5-diyloxy)]dibenzene-1,2-dicar Boxylic acid, 4,4'-[4,4'-(3-oxo-1,3-dihydro-2-benzofuran-1,1-diyl)bis(4-isopropyl-toluene-2,5- diyloxy)]dibenzene-1,2-dicarboxylic acid, 4,4'-[4,4'-(3-oxo-1,3-dihydro-2-benzofuran-1,1-diyl )bis(naphthalene-1,4-diyloxy)]dibenzene-1,2-dicarboxylic acid, 4,4'-[4,4'-(3H-2,1-benzoxathiol-1, 1-dioxide-3,3-diyl)bis(benzene-1,4-diyloxy)]dibenzene-1,2-dicarboxylic acid, 4,4'-benzophenonetetracarboxylic acid, 4,4 '-[(3H-2,1-benzoxathiol-1,1-dioxide-3,3-diyl)bis(toluene-2,5-diyloxy)]dibenzene-1,2-dicarboxylic acid , 4,4'-[(3H-2,1-benzoxathiol-1,1-dioxide-3,3-diyl)bis(1,4-xylene-2,5-diyloxy)]dibenzene- 1,2-dicarboxylic acid, 4,4'-[4,4'-(3H-2,1-benzoxathiol-1,1-dioxide-3,3-diyl)bis(4-isopropyl- toluene-2,5-diyloxy)]dibenzene-1,2-dicarboxylic acid, 4,4'-[4,4'-(3H-2,1-benzoxathiol-1,1-dioxide) -3,3-diyl)bis(naphthalene-1,4-diyloxy)]dibenzene-1,2-dicarboxylic acid, 3,3',4,4'-benzophenonetetracarboxylic 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(xanthene-9,9'-fluorene)-2,6-diylbis(oxy Tetracarboxylic acids such as carbonyl)]diphthalic acid, 4,4'-[spiro(xanthene-9,9'-fluorene)-3,6-diylbis(oxycarbonyl)]diphthalic acid, and these Acid anhydride may be mentioned. Among these, dianhydrides having two acid anhydride structures are suitable, and 4,4'-(2,2-hexafluoroisopropylidene)diphthalic dianhydride and 4,4'-oxydiphthalic dianhydride are particularly preferred. do. In addition, aromatic tetracarboxylic acids may be used individually, or two or more types may be used in combination. When heat resistance is important, the copolymerization amount of aromatic tetracarboxylic acids is preferably, for example, 50% by mass or more of the total tetracarboxylic acids, more preferably 60% by mass or more, and even more preferably 70% by mass or more. And, more preferably, it is 80 mass% or more, especially preferably 90 mass% or more, and even 100 mass% is not a problem.

Examples of alicyclic tetracarboxylic acids include 1,2,3,4-cyclobutanetetracarboxylic acid, 1,2,3,4-cyclopentanetetracarboxylic acid, and 1,2,3,4-cyclohexanetetracarboxylic acid. Boxylic acid, 1,2,4,5-cyclohexanetetracarboxylic acid, 3,3',4,4'-bicyclohexyltetracarboxylic 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-en-2 ,3,5,6-tetracarboxylic acid, tetrahydroanthracene-2,3,6,7-tetracarboxylic acid, 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-ethano-5,8-methanonaphthalene-2,3,6,7-tetracarboxylic acid, norbornane-2-spiro-α- Cyclopentanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid (aka "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 (aka "norbornane-2-spiro-2'-cyclohexanone-6'-spiro-2'' -norbornane-5,5'',6,6''-tetracarboxylic acid"), methylnorbornane-2-spiro-α-cyclohexanone-α'-spiro-2''-(methyl norbornane)-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''-tetra Carboxylic acid, norbornane-2-spiro-α-cyclooctanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid, norborn I-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''-norborne I-5,5'',6,6''-tetracarboxylic acid, norbornane-2-spiro-α-cyclotetradecanone-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''-tetracar Tetracarboxylic acids, such as boxylic acid, and their acid anhydrides can be mentioned. Among these, dianhydrides having two acid anhydride structures are suitable, especially 1,2,3,4-cyclobutane tetracarboxylic dianhydride, 1,2,3,4-cyclohexane tetracarboxylic dianhydride, 1, 2,4,5-cyclohexanetetracarboxylic dianhydride is preferred, and 1,2,3,4-cyclobutanetetracarboxylic dianhydride and 1,2,4,5-cyclohexanetetracarboxylic dianhydride are more preferred. Preferred, and 1,2,3,4-cyclobutanetetracarboxylic dianhydride is more preferred. In addition, these may be used individually, or two or more types may be used together. When transparency is important, the copolymerization amount of alicyclic tetracarboxylic acids is preferably, for example, 50% by mass or more of the total tetracarboxylic acids, more preferably 60% by mass or more, and even more preferably 70% by mass. or more, more preferably 80 mass% or more, particularly preferably 90 mass% or more, and even 100 mass% is not a problem.

Tricarboxylic acids include trimellitic acid, 1,2,5-naphthalene tricarboxylic acid, diphenyl ether-3,3',4'-tricarboxylic acid, and diphenyl sulfone-3,3',4'. -Aromatic tricarboxylic acids such as tricarboxylic acid, or hydrogenated products of these aromatic tricarboxylic acids such as hexahydrotrimellitic acid, ethylene glycol bistrimellitate, propylene glycol bistrimellitate, and 1,4-butanediol. Alkylene glycol bistrimellitate, such as bistrimellitate and polyethylene glycol bistrimellitate, and monoanhydrides and esters thereof are included. Among these, monoanhydrides having one acid anhydride structure are suitable, and trimellitic anhydride and hexahydrotrimellitic anhydride are particularly preferable. In addition, these may be used individually or may be used in combination.

As dicarboxylic acids, aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, orthophthalic acid, naphthalenedicarboxylic acid, 4,4'-oxydibenzenecarboxylic acid, or 1,6-cyclohexanedicarboxylic acid. Hydrogenated products of the above aromatic dicarboxylic acids, such as oxalic acid, succinic acid, glutaric acid, adipic acid, heptanoic acid, octanoic acid, azelaic acid, sebacic acid, undecanoic acid, dodecanoic acid, 2- Examples include methylsuccinic acid and acid chlorides or esters thereof. Among these, aromatic dicarboxylic acids and their hydrogenated products are suitable, and terephthalic acid, 1,6-cyclohexanedicarboxylic acid, and 4,4'-oxydibenzenecarboxylic acid are particularly preferable. In addition, dicarboxylic acids may be used individually or in combination of multiple dicarboxylic acids.

There are no particular restrictions on the diamines or isocyanates for obtaining a colorless and highly transparent polyimide, and include aromatic diamines, aliphatic diamines, and alicyclic diamines commonly used in polyimide synthesis, polyamidoimide synthesis, and polyamide synthesis, Aromatic diisocyanates, aliphatic diisocyanates, alicyclic diisocyanates, etc. can be used. Aromatic diamines are preferable from the viewpoint of heat resistance, and alicyclic diamines are preferable from the viewpoint of transparency. In addition, by using aromatic diamines having a benzoxazole structure, it is possible to exhibit high elastic modulus, low heat shrinkage, and low coefficient of linear expansion along with high heat resistance. Diamines and isocyanates may be used individually, or two or more types may be used together.

As aromatic diamines, for example, 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)bi Phenyl, 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'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone, 3,3'-diaminobenzophenone, 3,4'-diaminobenzophenone, 4,4'-diaminobenzo Phenone, 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-amino) Phenoxy)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]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) si) 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, 1,4-bis[4-(3-aminophenoxy)benzoyl]benzene, 4,4'-bis[(3-aminophenoxy)benzoyl]benzene, 1,1-bis[4-(3-aminophenok) Si) phenyl] propane, 1,3-bis [4- (3-aminophenoxy) phenyl] propane, 3,4'-diaminodiphenyl sulfide, 2,2-bis [3- (3-aminophenok) C)phenyl]-1,1,1,3,3,3-hexafluoropropane, bis[4-(3-aminophenoxy)phenyl]methane, 1,1-bis[4-(3-aminophenok) Si) phenyl] ethane, 1,2-bis [4- (3-aminophenoxy) phenyl] ethane, bis [4- (3-aminophenoxy) phenyl] sulfoxide, 4,4'-bis [3- (4-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]diphenylsulfone, bis[4-{4-(4- Aminophenoxy)phenoxy}phenyl]sulfone, 1,4-bis[4-(4-aminophenoxy)phenoxy-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(4-amino) Phenoxy) phenoxy-α,α-dimethylbenzyl]benzene, 1,3-bis[4-(4-amino-6-trifluoromethylphenoxy)-α,α-dimethylbenzyl]benzene, 1,3 -bis[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'-dipe Noxybenzophenone, 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'-phenoc Cybenzophenone, 3,3'-diamino-4,4'-divinoxybenzophenone, 4,4'-diamino-5,5'-diviphenoxybenzophenone, 3,4'-diamino- 4,5'-Dibiphenoxybenzophenone, 3,3'-Diamino-4-biphenoxybenzophenone, 4,4'-Diamino-5-biphenoxybenzophenone, 3,4'-Diamino -4-biphenoxybenzophenone, 3,4'-diamino-5'-biphenoxybenzophenone, 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-biphenoxybenzoyl)benzene, 1,4-bis(3-amino-4-biphenoxybenzoyl)benzene, 1,3-bis(4-amino-5-biphenok) Cibenzoyl)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]bisaniline (aka "9,9-bis(4-aminophenyl)fluorene"), spiro(xanthene-9,9'-fluorene )-2,6-diylbis(oxycarbonyl)]bisaniline, 4,4'-[spiro(xanthene-9,9'-fluorene)-2,6-diylbis(oxycarbonyl)]bis Aniline, 4,4'-[spiro(xanthene-9,9'-fluorene)-3,6-diylbis(oxycarbonyl)]bisaniline, etc. can be mentioned. In addition, some or all of the hydrogen atoms on the aromatic ring of the aromatic diamine may be substituted with a halogen atom, an alkyl group having 1 to 3 carbon atoms, an alkoxyl group, or a cyano group, and the hydrogen atoms of the alkyl group or alkoxyl group having 1 to 3 carbon atoms may be substituted. Part or all of may be substituted with a halogen atom. In addition, the aromatic diamines having the above-mentioned benzoxazole structure are not particularly limited, and examples include 5-amino-2-(p-aminophenyl)benzoxazole, 6-amino-2-(p-aminophenyl)benzooxa. Sol, 5-amino-2-(m-aminophenyl)benzoxazole, 6-amino-2-(m-aminophenyl)benzoxazole, 2,2'-p-phenylenebis(5-aminobenzooxa sol), 2,2'-p-phenylenebis(6-aminobenzoxazole), 1-(5-aminobenzooxazolo)-4-(6-aminobenzooxazolo)benzene, 2,6-( 4,4'-diaminodiphenyl)benzo[1,2-d:5,4-d']bisoxazole, 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: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. I can hear it. Among these, especially 2,2'-ditrifluoromethyl-4,4'-diaminobiphenyl, 4-amino-N-(4-aminophenyl)benzamide, 4,4'-diaminodiphenylsulfone, 3,3'-Diaminobenzophenone is preferred. In addition, aromatic diamines may be used individually or may be used in combination of plurality.

Examples of alicyclic diamines include 1,4-diaminocyclohexane, 1,4-diamino-2-methylcyclohexane, 1,4-diamino-2-ethylcyclohexane, and 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, 4,4'-methylenebis(2,6-dimethylcyclohexylamine), etc. You can. Among these, 1,4-diaminocyclohexane and 1,4-diamino-2-methylcyclohexane are particularly preferable, and 1,4-diaminocyclohexane is more preferable. In addition, alicyclic diamines may be used individually or may be used in combination.

Examples of diisocyanates include 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'-diisocyanate, diphenylsulfone-4,4'-diisocyanate, tolylene-2,4-diisocyanate, tolylene-2,6-diisocyanate, m-xylylene diisocyanate, p- Xylylene diisocyanate, naphthalene-2,6-diisocyanate, 4,4'-(2,2bis(4-phenoxyphenyl)propane)diisocyanate, 3,3'- or 2,2'-dimethylbiphenyl -4,4'-diisocyanate, 3,3'- or 2,2'-diethylbiphenyl-4,4'-diisocyanate, 3,3'-dimethoxybiphenyl-4,4'-diisocyanate , aromatic diisocyanates such as 3,3'-diethoxybiphenyl-4,4'-diisocyanate, and diisocyanates obtained by hydrogenating any one of them (e.g., isophorone diisocyanate, 1,4-cyclohexane diisocyanate) , 1,3-cyclohexane diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, hexamethylene diisocyanate), etc. Among these, diphenylmethane-4,4'-diisocyanate, tolylene-2,4-diisocyanate, tolylene-2,6-diisocyanate, 3, in terms of low hygroscopicity, dimensional stability, price and polymerizability. 3'-dimethylbiphenyl-4,4'-diisocyanate, naphthalene-2,6-diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, and 1,4-cyclohexane diisocyanate are preferred. In addition, diisocyanates may be used individually or in combination of multiple diisocyanates.

In this embodiment, it is preferable that the polymer film is a polyimide film. If the polymer film is a polyimide film, it has excellent heat resistance. Additionally, if the polymer film is a polyimide film, it can be suitably drilled with a laser.

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. The upper limit of the thickness of the polymer film is not particularly limited, but for use as a flexible circuit board, it is preferably 250 μm or less, more preferably 100 μm or less, and even more preferably 50 μm or less.

It is preferable that the average coefficient of linear expansion (CTE) of the polymer film between 30°C and 250°C is 50 ppm/K or less. More preferably, it is 45 ppm/K or less, further preferably is 40 ppm/K or less, even more preferably is 30 ppm/K or less, and particularly preferably is 20 ppm/K or less. Also, it is preferably -5 ppm/K or more, more preferably -3 ppm/K or more, and even more preferably 1 ppm/K or more. If the CTE is within the above range, the difference in linear expansion coefficient with a general support (inorganic substrate) can be kept small, and peeling of the polymer film and the inorganic substrate or bending of the support can be avoided even when used in a heat application process. Here, CTE is a factor representing reversible expansion and contraction with respect to temperature. In addition, 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.

When the polymer film is a transparent polyimide film, the yellowness index (hereinafter also referred to as “yellow index” or “YI”) is preferably 10 or less, more preferably 7 or less, and even more preferably 5. or less, and more preferably 3 or less. The lower limit of the yellowness index of the transparent polyimide is not particularly limited, but for use as a flexible circuit board, it is preferably 0.1 or more, more preferably 0.2 or more, and still more preferably 0.3 or more.

When the polymer film is a transparent polyimide film, the haze is preferably 1.0 or less, more preferably 0.8 or less, further preferably 0.5 or less, and even more preferably 0.3 or less. The lower limit is not particularly limited, but industrially, there is no problem as long as it is 0.01 or more, and even if it is 0.05 or more, there is no problem.

The heat shrinkage rate of the polymer film between 30°C and 500°C is preferably ±0.9% or less, and more preferably ±0.6% or less. Thermal contraction rate is a factor that indicates irreversible expansion and contraction with respect to temperature.

The tensile breaking strength of the polymer film is preferably 60 MPa or more, more preferably 80 MPa or more, and even more preferably 100 MPa or more. The upper limit of the tensile breaking strength is not particularly limited, but is in fact less than about 1000 MPa. If the tensile breaking strength is 60 MPa or more, it is possible to prevent the polymer film from breaking when peeling from the inorganic substrate. In addition, the tensile breaking strength of the polymer film refers to the average value of the tensile breaking strength in the flow direction (MD direction) and the tensile breaking strength in the width direction (TD direction) of the polymer film.

The tensile elongation at break of the polymer film is preferably 1% or more, more preferably 5% or more, and even more preferably 10% or more. If the tensile elongation at break is 1% or more, handleability is excellent. In addition, the tensile elongation at break of the polymer film refers to the average value of the tensile elongation at break in the flow direction (MD direction) and the tensile elongation at break in the width direction (TD direction) of the polymer film.

The tensile elastic modulus of the polymer film is preferably 2.5 GPa or more, more preferably 3 GPa or more, and even more preferably 4 GPa or more. If the tensile elastic modulus is 2.5 GPa or more, the stretching strain of the polymer film when peeled from the inorganic substrate is small, and handling properties are excellent. The tensile modulus is preferably 20 GPa or less, more preferably 15 GPa or less, and even more preferably 12 GPa or less. If the tensile modulus is 20 GPa or less, the polymer film can be used as a flexible film. In addition, the tensile elastic modulus of the polymer film refers to the average value of the tensile elastic modulus in the flow direction (MD direction) and the tensile elastic modulus in the width direction (TD direction) of the polymer film.

The thickness unevenness of the polymer film is preferably 20% or less, more preferably 12% or less, further preferably 7% or less, and particularly preferably 4% or less. If the thickness unevenness exceeds 20%, it tends to become difficult to apply to narrow areas. In addition, the thickness unevenness of the film can be determined based on the following equation by, for example, extracting about 10 positions at random from the film to be measured using a contact-type film thickness meter and measuring the film thickness.

Film thickness unevenness (%)=

100×(maximum film thickness-minimum film thickness)÷average film thickness

The polymer film is preferably obtained in a wound form as a long polymer film with a width of 300 mm or more and a length of 10 m or more during its production, and is more preferably in the form of a roll-shaped polymer film wound on a winding core. If the polymer film is wound in a roll shape, it becomes easy to transport in the form of a roll-shaped polymer film.

In the above polymer film, in order to ensure handling properties and productivity, about 0.03 to 3% by mass of a lubricant (particles) with a particle diameter of about 10 to 1000 nm is added or contained in the polymer film to form fine particles on the surface of the polymer film. It is desirable to secure slipperiness by providing irregularities.

<Protective film (first protective film, second protective film)>

The composition of the protective film is not particularly limited, but it is preferable to have a base material and an adhesive layer formed on the base material. The protective film may have layers other than the base material and the adhesive layer. However, it is preferable that the adhesive layer is laminated in a manner that is in contact with the heat-resistant polymer film. Therefore, it is preferable that the adhesive layer is located on the outermost surface of the protective film.

<Description>

The substrate serves as a strength matrix for the protective film.

The substrate is not particularly limited, but the tensile modulus at 25°C is preferably 0.01 GPa or more, more preferably 1 GPa or more, and still more preferably 2 GPa or more. If the tensile elastic modulus of the substrate at 25°C is 0.3 GPa or more, the surface of the heat-resistant polymer film can be suitably protected. Additionally, the tensile modulus of elasticity of the base material at 25°C can be, for example, 10 GPa or less, 5 GPa or less, from the viewpoint of being able to bend the protective film when peeling it from the heat-resistant polymer film.

In this specification, the tensile modulus of elasticity of the substrate at 25°C is determined using a test piece cut from the substrate into a strip of 100 mm x 10 mm, using a tensile tester (Autograph (R), manufactured by Shimadzu Corporation, model name). This refers to the value measured using AG-5000A) under the conditions of a tensile speed of 50 mm/min and a distance between chucks of 40 mm.

Materials for the base material include polyolefin resins such as polyethylene and polypropylene; Polyamide resins such as nylon 6 and nylon 66; and polyester resins such as polyethylene terephthalate, polytrimethylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate, and polytrimethylene terephthalate. These may be used interchangeably. The polyester resin is a copolymerization component, for example, diol components such as diethylene glycol, neopentyl glycol, and polyalkylene glycol, adipic acid, sebacic acid, phthalic acid, isophthalic acid, and 2,6-naphthalenedicarboxylic acid. A polyester resin copolymerized with dicarboxylic acid components, etc. may also be used. Among them, polyester resin is preferable in terms of mechanical strength, chemical resistance, and heat resistance.

Among the polyester resins, polyethylene terephthalate is most preferable in terms of balance between physical properties and cost.

The substrate is preferably biaxially stretched. If biaxially stretched, chemical resistance, heat resistance, mechanical strength, etc. can be improved.

The substrate may be a single layer or a double layer.

The base material may contain various additives in the resin as needed. Examples of the additives include antioxidants, anti-light agents, gelling agents, organic wetting agents, ultraviolet absorbers, and surfactants.

The substrate may be transparent or colored. The method for coloring the above-mentioned substrate is not particularly limited, but can be colored by adding a pigment or dye. For example, mixing a white pigment such as titanium oxide to form a white film is also suitable because visibility can be improved.

In order to ensure handleability and productivity, the substrate is made to contain about 0.03 to 3% by mass of a lubricant (particles) with a particle diameter of about 10 to 1000 nm, and fine irregularities are given to the surface of the substrate to make it slippery. It is desirable to secure the castle.

The thickness of the substrate is not particularly limited, but can be arbitrarily determined according to the standard used, for example, in the range of 12 to 500 μm. The thickness of the substrate is more preferably 350 ㎛ or less. If the thickness of the base material is 350 μm or less, a decrease in productivity and handling properties can be suppressed. Additionally, the thickness of the substrate is more preferably in the range of 25 ㎛ to 50 ㎛. If the thickness of the base material is 25 μm or more, the lack of mechanical strength of the base material can be reduced and fracture during peeling can be prevented.

The above substrate can be formed into a film using a conventionally known film forming method. Examples of the film forming method include a calendar film forming method, a casting method in an organic solvent, an inflation extrusion method in a closed system, a T-die extrusion method, a co-extrusion method, and a dry laminate method.

<Adhesive layer>

The adhesive layer generally has a low elastic modulus compared to the substrate or the heat-resistant polymer film (for example, the tensile modulus is two orders of magnitude or more lower than the substrate or the heat-resistant polymer film).

The adhesive layer is not particularly limited, and known materials such as acrylic, silicone, rubber, polyester, and urethane can be used. From the viewpoint of handleability, acrylic resin and silicone resin are preferable.

The acrylic resin is obtained by polymerizing monomers such as (meth)acrylic acid alkyl ester. Specific examples of the monomers include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, iso-butyl (meth)acrylate, t-butyl ( Meth)acrylate, n-hexyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, n-octyl(meth)acrylate, iso-octyl(meth)acrylate, lauryl(meth)acrylate, Alkyl (meth)acrylate compounds such as stearyl (meth)acrylate can be mentioned. These may be copolymerized in plurality as needed.

The adhesive layer is usually formed on the entire surface of the substrate. However, the present invention is not limited to this example, and there may be a portion on the surface of the substrate where an adhesive layer is not formed. For example, the vicinity of both ends of the surface of the substrate in the width direction may be configured so that no adhesive layer is formed.

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

The adhesive layer can be obtained by applying a pressure-sensitive adhesive composition solution on the substrate to form a coating film, and then drying the coating film under predetermined conditions. The application method is not particularly limited, and examples include roll coating, screen coating, and gravure coating. Additionally, drying conditions include, for example, a drying temperature of 80 to 150°C and a drying time of 0.5 to 5 minutes. Additionally, after applying the adhesive composition on the separator to form a coating film, the coating film may be dried under the above drying conditions to form an adhesive layer. Thereafter, the adhesive layer is bonded together with a separator on the substrate. A protective film can be obtained as described above.

<Other floors>

The protective film may have layers other than the base material and the adhesive layer. For example, the protective film may have an oligomer block layer, an antistatic layer, etc. A release treatment layer may be provided on the surface of the substrate opposite to the surface on which the adhesive layer is formed. If it has the release treatment layer, the protective film can be wound into a roll, for example, before bonding it to a heat-resistant polymer film. That is, even if the protective film is wound in a roll shape, the adhesive layer does not directly contact the back surface of the substrate but touches the peeling treatment layer, thereby preventing the adhesive layer from adhering (transferring) to the back surface of the substrate. there is.

The release treatment layer preferably contains at least one selected from silicone resin and fluorine resin as a main component. As the silicone resin, silicone resins generally used in release treatment agents can be used, and silicone resins commonly used in the field described in the "Silicone Materials Handbook" (Toray Dow Corning edition, August 1993) can be selected and used. . Generally, heat-curable or ionizing radiation-curable silicone resins (including resins and resin compositions) are used. As a thermosetting type silicone resin, for example, condensation reaction type and addition reaction type silicone resin can be used, and as an ionizing radiation curing type silicone resin, an ultraviolet ray or electron beam curing type silicone resin, etc. can be used. The peeling treatment layer can be formed by applying these onto the substrate and drying or curing them.

The first protective film and the second protective film may have the same structure or different structures.

After forming the through hole 13 in the heat-resistant polymer film 12, the first protective film 14 is peeled off.

Additionally, if the first protective film is not adhered to the first side of the heat-resistant polymer film when forming the through hole, this process is not necessary.

<Process B>

Next, as shown in FIG. 3, the release film 18 is attached to the first surface 12a of the heat-resistant polymer film 12 on which the through hole 13 is formed.

<The above release film>

As the release film, the same structure as described in the section regarding the protective film (the first protective film and the second protective film) can be adopted. The specific structure of the release film may be the same as or different from that of the protective film (the first protective film and the second protective film).

<Process C>

Next, as shown in FIG. 4, from the second surface 12b side of the heat-resistant polymer film 12 on which the through-hole 13 is formed, the release film 18 is placed on the heat-resistant polymer film 12 and in the through-hole 13. ) Form a metal layer 20 on the. At this time, it goes without saying that the metal layer 20 is also formed on the inner wall of the through hole 13.

A conventionally known method can be adopted as a method of forming the metal layer 20. For example, the metal layer 20 is formed on the heat-resistant polymer film 12 and the release film 18 in the through hole 13 by sputtering or electrolytic plating.

The metal constituting the metal layer 20 is not particularly limited, but may be a single metal such as copper, gold, silver, platinum, lead, tin, nickel, cobalt, indium, rhodium, chromium, tungsten, and ruthenium, or two or more types of these. An alloy containing , etc. may be mentioned.

The thickness of the metal layer 20 on the heat-resistant polymer film 12 is not particularly limited, but may be appropriately set in the range of 20 to 20,000 nm.

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) may be on the same surface, or there may be a step as shown in FIG. 4. .

By performing step C, a circuit board precursor 30 with a release film can be obtained, which includes the release film 18, the heat-resistant polymer film 12 having the through hole 13, and the metal layer 20.

In the release film-equipped circuit board precursor 30, a heat-resistant polymer film 12 is formed on a release film 18. In addition, in the circuit board precursor with a release film 30, the metal layer 20 is formed on the heat-resistant polymer film 12 and on the release film 18 in the through hole 13.

In the release film-equipped circuit board precursor 30, the release film 18 is easily peeled, so the heat-resistant polymer film 12 can be easily peeled from the release film 18. In addition, as described later, when the heat-resistant polymer film 12 is peeled from the release film 18 and patterning is performed on the metal layer 20 on the heat-resistant polymer film 12 after adhering it to the inorganic substrate 40, the metal layer There is little heat history when (20) and the release film (18) are in contact. As a result, adhesion of the metal layer 20 and the release film 18 can be prevented.

In addition, in this embodiment, the case where the entire heat-resistant polymer film 12 is formed on the release film 18 is shown and explained, but the present invention is not limited to this example. In the present invention, “the heat-resistant polymer film is formed on the release film” includes the case where at least a part of the heat-resistant polymer film is formed on the release film. For example, the case where another layer exists in a part between the heat-resistant polymer film and the release film is also included in “the heat-resistant polymer film is formed on the release film.”

<Process D>

After step C, as shown in FIG. 5, the release film 18 is peeled from the heat-resistant polymer film 12.

The method of peeling the release film 18 from the heat-resistant polymer film 12 is not particularly limited, and includes a method of lifting the release film 18 from the end with tweezers or the like, or a method of attaching an adhesive tape to one side of the release film 18 and then peeling the release film 18 from the tape portion. A roll-up method, a method of vacuum-sucking one side of the release film 18 and then roll-up from that part, etc. can be adopted.

<Process E>

Additionally, in the circuit board manufacturing method according to the present embodiment, the inorganic substrate 40 having the silane coupling agent layer 42 is prepared separately from the above steps A to D.

<Inorganic substrate>

The inorganic substrate may be any plate-shaped that can be used as a substrate containing an inorganic material, for example, a substrate mainly made of glass plates, ceramic plates, semiconductor wafers, metals, etc., and composites of these glass plates, ceramic plates, semiconductor wafers, and metals. Examples include those that are laminated, those that are dispersed, those that contain these fibers, etc.

As the glass plate, quartz glass, high silica glass (96% silica), soda lime glass, lead glass, aluminoborosilicate glass, borosilicate glass (Pilex (registered trademark)), borosilicate glass (alkali-free), borosilicate glass (micro sheet), aluminosilicate glass, etc. Among these, those with a linear expansion coefficient of 5 ppm/K or less are preferable. Commercially available products include liquid crystal glass, such as "Corning (registered trademark) 7059" manufactured by Corning, "Corning (registered trademark) 1737", and "EAGLE" manufactured by Asahi Glass. "AN100", "OA10" manufactured by Nippon Denki Glass, and "AF32" manufactured by SCHOTT, etc. are preferred.

The semiconductor wafer is not particularly limited, but includes silicon wafer, germanium, silicon-germanium, gallium-arsenide, aluminum-gallium-indium, nitrogen-phosphorus-arsenic-antimony, SiC, InP (indium phosphorus), InGaAs, GaInNAs, LT. , LN, ZnO (zinc oxide), CdTe (cadmium telluride), and ZnSe (zinc selenide) wafers. Among these, the wafer used preferably is a silicon wafer, and a mirror-polished silicon wafer with a size of 8 inches or more is particularly preferable.

The metal includes single element metals such as W, Mo, Pt, Fe, Ni, and Au, and alloys such as Inconel, Monel, Nimonic, carbon steel, Fe-Ni-based Invar alloy, and super Invar alloy. It also includes multilayer metal plates made by adding other metal layers and ceramic layers to these metals. In this case, if the overall coefficient of linear expansion (CTE) with the additional layer is low, Cu, Al, etc. are also used in the main metal layer. The metal used in the additional metal layer is not limited as long as it has properties such as strong adhesion to the polymer film, no diffusion, and good chemical and heat resistance, but contains Cr, Ni, TiN, and Mo. Cu and the like can be cited as suitable examples.

It is preferable that the planar portion of the inorganic substrate is sufficiently flat. Specifically, the P-V value of the surface roughness is 50 nm or less, more preferably 20 nm or less, and even more preferably 5 nm or less. If it is rougher than this, the peeling strength between the polymer film and the inorganic substrate may become insufficient.

The thickness of the inorganic substrate is not particularly limited, but from the viewpoint of handling, a thickness of 10 mm or less is preferable, 3 mm or less is more preferable, and 1.3 mm or less is still more preferable. 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.

<Silane coupling agent layer>

The silane coupling agent layer physically or chemically intervenes between the inorganic substrate and the polymer film and has the function of increasing the adhesive force between the two.

The silane coupling agent is not particularly limited, but preferably contains a coupling agent having an amino group. Preferred specific examples of silane coupling agents include N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl)-3-aminopropyltrimethoxysilane, and N-2-(aminoethyl)-3-aminopropyltrimethoxysilane. Ethyl)-3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-triethoxysilyl-N-(1,3-dimethyl-butylidene) Propylamine, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriene Toxysilane, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3- Glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, p-styryltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane , 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltrimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-(vinyl Benzyl)-2-aminoethyl-3-aminopropyltrimethoxysilane hydrochloride, 3-ureidopropyltriethoxysilane, 3-chloropropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, 3-mer Captopropyltrimethoxysilane, bis(triethoxysilylpropyl)tetrasulfide, 3-isocyanate propyltriethoxysilane, tris(3-trimethoxysilylpropyl)isocyanurate, chloromethylphenethyltrimethoxysilane , chloromethyltrimethoxysilane, aminophenyltrimethoxysilane, aminophenethyltrimethoxysilane, aminophenylaminomethylphenethyltrimethoxysilane, etc.

As the silane coupling agent, in addition to the above, n-propyltrimethoxysilane, butyltrichlorosilane, 2-cyanoethyltriethoxysilane, cyclohexyltrichlorosilane, decyltrichlorosilane, and diacetoxydimethylsilane. , diethoxydimethylsilane, dimethoxydimethylsilane, dimethoxydiphenylsilane, dimethoxymethylphenylsilane, dodecyltrichlorosilane, dodecyltrimethoxysilane, ethyltrichlorosilane, hexyltrimethoxysilane, octadecyltriene Toxysilane, octadecyltrimethoxysilane, n-octyltrichlorosilane, n-octyltriethoxysilane, n-octyltrimethoxysilane, triethoxyethylsilane, triethoxymethylsilane, trimethoxymethylsilane , trimethoxyphenylsilane, pentyltriethoxysilane, pentyltrichlorosilane, triacetoxymethylsilane, trichlorohexylsilane, trichloromethylsilane, trichlorooctadecylsilane, trichloropropylsilane, trichlorotetradecylsilane. , trimethoxypropylsilane, allyltrichlorosilane, allyltriethoxysilane, allyltrimethoxysilane, diethoxymethylvinylsilane, dimethoxymethylvinylsilane, trichlorovinylsilane, triethoxyvinylsilane, vinyltris( 2-methoxyethoxy)silane, trichloro-2-cyanoethylsilane, diethoxy(3-glycidyloxypropyl)methylsilane, 3-glycidyloxypropyl(dimethoxy)methylsilane, 3-gly Cydyloxypropyltrimethoxysilane, etc. can also be used.

Among the above silane coupling agents, silane coupling agents having one silicon atom in one molecule are particularly preferable, such as N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, N-2-(aminoethyl )-3-Aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-tri Ethoxysilyl-N-(1,3-dimethyl-butylidene)propylamine, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3- Glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, aminophenyltrimethoxysilane, aminophenethyltrimethoxysilane, aminophenylaminomethylphenethyltrimethoxysilane, etc. are mentioned. In particular, when high heat resistance is required, it is preferable to connect Si and the amino group with an aromatic group.

A coupling layer other than the silane coupling agent layer may be formed on the inorganic substrate.

As a coupling agent for forming the coupling layer, in addition to the above, 1-mercapto-2-propanol, methyl 3-mercaptopropionate, 3-mercapto-2-butanol, butyl 3-mercaptopropionate, 3- (dimethoxymethylsilyl)-1-propanethiol, 4-(6-mercaptohexanoyl)benzyl alcohol, 11-amino-1-undecenethiol, 11-mercaptoundecylphosphonic acid, 11-mercaptoundecyl Trifluoroacetic acid, 2,2'-(ethylenedioxy)diethanethiol, 11-mercaptoundecyltri(ethylene glycol), (1-mercaptoundecyl-11-yl)tetra(ethylene glycol), 1 -(Methylcarboxy)undec-11-yl)hexa(ethylene glycol), hydroxyundecyldisulfide, carboxyundecyldisulfide, hydroxyhexadodecyldisulfide, carboxyhexadecyldisulfide, tetrakis(2-ethyl Hexyloxy) titanium, titanium dioctyloxybis (octylene glycolate), zirconium tributoxy monoacetylacetonate, zirconium monobutoxy acetylacetonate bis (ethylacetoacetate), zirconium tributoxy monostearate, aceto Alkoxyaluminum diisopropylate, 3-glycidyloxypropyltrimethoxysilane, 2,3-butanedithiol, 1-butanethiol, 2-butanethiol, cyclohexanethiol, cyclopentanethiol, 1-decanethiol, 1-Dodecanethiol, 3-mercaptopropionate-2-ethylhexyl, 3-mercaptopropionate ethyl, 1-heptanethiol, 1-hexadecanethiol, hexyl mercaptan, isoamyl mercaptan, isobutyl mercaptan, 3 -Mercaptopropionic acid, 3-mercaptopropionic acid-3-methoxybutyl, 2-methyl-1-butanethiol, 1-octadecanethiol, 1-octanethiol, 1-pentadecanethiol, 1-pentanethiol, 1- Propanethiol, 1-tetradecanethiol, 1-undecanethiol, 1-(12-mercaptododecyl)imidazole, 1-(11-mercaptoundecyl)imidazole, 1-(10-mercaptodecyl) Imidazole, 1-(16-mercaptohexadecyl)imidazole, 1-(17-mercaptoheptadecyl)imidazole, 1-(15-mercapto-)dodecanoic acid, 1-(11-mercapto-) Undecanoic acid, 1-(10-mercapto)decanoic acid, etc. can also be used.

As a method of applying the silane coupling agent (method of forming the silane coupling agent layer), a method of applying a silane coupling agent solution to an inorganic substrate, a vapor deposition method, etc. can be used.

Methods for applying the silane coupling agent solution include spin coating, curtain coating, dip coating, slit die coating, gravure coating, and bar coating using a diluted solution of the silane coupling agent with a solvent such as alcohol. , conventionally known solution application means such as the comma coat method, applicator method, screen printing method, and spray coating method can be appropriately used.

A method of forming the silane coupling agent layer by vapor deposition includes exposing the inorganic substrate to vapor of the silane coupling agent, that is, substantially in a gaseous state. The vapor of the silane coupling agent can be obtained by heating the liquid silane coupling agent to a temperature ranging from 40°C to the boiling point of the silane coupling agent. The boiling point of the silane coupling agent varies depending on the chemical structure, but is approximately in the range of 100 to 250°C.

The environment in which the silane coupling agent is heated may be under pressurized pressure, normal pressure, or reduced pressure, but when promoting vaporization of the silane coupling agent, under normal pressure to reduced pressure is preferable. Since many silane coupling agents are flammable liquids, it is better to perform vaporization in a closed container, preferably after purging the inside of the container with an inert gas.

The time for exposing the inorganic substrate to the silane coupling agent is not particularly limited, but is preferably within 20 hours, more preferably within 60 minutes, further preferably within 15 minutes, and most preferably within 1 minute.

The temperature of the inorganic substrate while exposing the inorganic substrate to the silane coupling agent is preferably controlled to an appropriate temperature between -50°C and 200°C depending on the type of silane coupling agent and the thickness of the silane coupling agent layer obtained. .

The thickness of the silane coupling agent layer 42 is not particularly limited, but may be sufficient to cover the entire surface of the inorganic substrate.

<Process F>

After step D, as shown in FIG. 6, an inorganic bond is applied to the first surface 12a of the heat-resistant polymer film 12 after peeling off the release film 18, using the silane coupling agent layer 42 as a bonding surface. The substrate 40 is adhered. Specifically, the first surface 12a of the heat-resistant polymer film 12 and the inorganic substrate 40 are bonded by pressing and heating. The inorganic substrate 40 prepared in process E is used.

Pressure heat treatment may be performed, for example, by heating a press, laminate, roll laminate, etc. under an atmospheric pressure atmosphere or in a vacuum. Additionally, a method of pressurizing and heating while placed in a flexible bag can also be applied. From the viewpoint of improving productivity and lowering processing costs through high productivity, press or roll lamination under an atmospheric atmosphere is preferable, and methods using rolls (roll lamination, etc.) are particularly preferable.

The pressure during pressurized heat treatment is preferably 1 MPa to 20 MPa, and more preferably 3 MPa to 10 MPa. If it is 20 MPa or less, damage to the inorganic substrate can be suppressed. Moreover, if it is 1 MPa or more, it is possible to prevent the occurrence of parts that are not in close contact or insufficient adhesion. The temperature during pressurization and heat treatment is preferably 150°C to 400°C, more preferably 250°C to 350°C.

In addition, the pressure heat treatment can be performed in an atmospheric pressure atmosphere as described above, but it is preferable to perform it under vacuum in order to obtain stable peeling strength of the entire surface. At this time, the vacuum degree obtained by a normal oil rotary pump is sufficient, and 10 Torr or less is sufficient.

As a device that can be used for pressurization and heat treatment, for pressing in a vacuum, for example, "11FD" manufactured by Imoto Seisakusho, etc. can be used, and a roll-type film laminator in a vacuum or a thin rubber laminator after vacuuming can be used. To perform vacuum lamination using a film laminator that applies pressure to the entire glass at once with a film, for example, “MVLP” manufactured by Meiki Seisakusho, etc. can be used.

The pressurization and heat treatment can be performed separately into a pressurization process and a heating process. In this case, first, the polymer film and the inorganic substrate are pressed (preferably about 0.2 to 50 MPa) at a relatively low temperature (e.g., less than 120°C, more preferably less than 95°C) to ensure close adhesion between the two, and then , by heating at low pressure (preferably less than 0.2 MPa, more preferably less than 0.1 MPa) or normal pressure at a relatively high temperature (e.g., 120°C or more, more preferably 120 to 250°C, even more preferably 150 to 230°C). , the chemical reaction at the adhesion interface is promoted, allowing polymer films and inorganic substrates to be laminated.

By performing the above step F, the inorganic substrate-equipped circuit is provided with the inorganic substrate 40, the silane coupling agent layer 42, the heat-resistant polymer film 12 having the through hole 13, and the metal layer 20. A substrate precursor 50 can be obtained.

In the circuit board precursor 50 with an inorganic substrate, a silane coupling agent layer 42 is formed on the inorganic substrate 40. In addition, in the circuit board precursor 50 with an inorganic substrate, a heat-resistant polymer film 12 is formed on the silane coupling agent layer 42. In addition, in the circuit board precursor 50 with an inorganic substrate, the metal layer 20 is formed on the heat-resistant polymer film 12 and on the silane coupling agent layer 42 in the through hole 13.

In the circuit board precursor 50 with an inorganic substrate, the metal layer 20 in the through hole 13 is simply adhered to the silane coupling agent layer 42 with appropriate adhesion, and thereafter, even when subjected to heat history, the metal layer 20 is attached to the inorganic substrate 40. There is no such thing as being firmly fixed. In addition, the silane coupling agent layer 42 and the heat-resistant polymer film 12 are only adhered with an appropriate adhesion force, and are not strongly adhered to the inorganic substrate 40 even when subjected to heat history thereafter. Therefore, after step G of patterning the metal layer 20, which will be described later, the inorganic substrate 40 with the silane coupling agent layer 42 can be easily peeled from the heat-resistant polymer film 12, such as by pulling it off. That is, the inorganic substrate 40 can be easily peeled from the heat-resistant polymer film 12 using the silane coupling agent layer 42 and the heat-resistant polymer film 12 as an interface. Since the inorganic substrate 40 can be peeled off from the heat-resistant polymer film 12 by pulling it off, a peeling chemical solution for peeling off the inorganic substrate 40 is attached to the patterned metal layer 20 or irradiated with plasma, etc. What cannot happen is that it becomes. As a result, the circuit board can be peeled from the inorganic substrate 40 without damaging the circuit board (patterned metal layer) formed on the inorganic substrate 40 as much as possible.

<Process G>

After step F, the metal layer 20 is patterned as shown in FIG. 7. The method of patterning the metal layer 20 is not particularly limited, and conventionally known techniques can be used. For example, the patterned metal layer 20 (also referred to as the wiring layer 21) can be obtained by etching the metal layer 20 into a predetermined pattern (wiring pattern) using a conventionally known etching technique.

Thereafter, a second wiring layer or the like may be formed on the wiring layer 21 as needed. Hereinafter, the case of forming the second wiring layer will be described.

<Process G-1>

After step G, as shown in FIG. 8, an adhesive is applied to the entire surface of the wiring layer 21 and cured to form an adhesive layer 44 (process G-1). As the adhesive, a conventionally known adhesive (for example, an adhesive containing a thermosetting resin or an adhesive containing an ultraviolet curing resin, etc.) can be employed. The adhesive is preferably formed of a material that forms an insulating adhesive layer after curing.

<Process G-2>

After step G-1, as shown in FIG. 9, the second heat-resistant polymer film 46 is adhered onto the adhesive layer 44. By heating and pressing during bonding, the surface of the adhesive layer 44 can be made more flat.

Additionally, the order of the step G-1 and the step G-2 is not particularly limited. For example, before applying and curing the adhesive on the entire surface of the wiring layer 21, the second heat-resistant polymer film 46 may be adhered, and the adhesive layer may then be cured.

The second heat-resistant polymer film 46 may have the same configuration as described in the section on heat-resistant polymer film. The heat-resistant polymer film 12 and the second heat-resistant polymer film 46 may have the same structure or different structures.

<Process G-3>

After step G-2, a through hole communicating with the second heat-resistant polymer film 46 and the adhesive layer 44 is formed, and plating is applied to the inner wall of the through hole to form a through hole 48. Additionally, a second wiring layer 49 is formed on the second heat-resistant polymer film 46. Accordingly, a circuit with two wiring layers, in which the wiring layer 21 and the second wiring layer 49 are connected, can be obtained (see Fig. 10). Formation of the through hole, formation of the through hole 48, and formation of the wiring layer 49 may employ conventionally known techniques.

At this time, the same process may be repeated to further form another wiring layer on the second wiring layer 49 to form a multilayer circuit (see FIG. 10).

Additionally, semiconductor chips may be stacked so as to be connected to the uppermost wiring layer (not shown).

At this time, if necessary, a photosensitive film may be employed as the second heat-resistant polymer film 46, exposed, and developed to pattern the second heat-resistant polymer film 46.

<Process H>

After Step G, if necessary, Steps G-1 to G-3 are additionally performed, and then the inorganic substrate 40 is peeled from the heat-resistant polymer film 12 (see Fig. 11). As described above, the circuit board 60 can be obtained.

The method of peeling the inorganic substrate 40 from the heat-resistant polymer film 12 is not particularly limited, but the inorganic substrate 40 is separated by laser light having a wavelength that penetrates the inorganic substrate and is absorbed by the heat-resistant polymer film 12. Existing methods such as laser lift-off, which peels off the heat-resistant polymer film 12 by focusing laser energy on the interface, or mechanical lift-off, which peels off along an arc with a large radius of curvature, can be used.

A simpler method would be to lift it up from the end with tweezers.

According to the circuit board manufacturing method according to the present embodiment, in step C, the metal layer 20 is formed on the release film 18 in the through hole 13. Since the release film 18 is easy to peel, the heat-resistant polymer film 12 can be easily peeled from the release film 18 even after forming the metal layer 20. In addition, after forming the metal layer 20, the heat-resistant polymer film 12 is peeled from the release film 18, and patterning is performed after adhering it to the inorganic substrate 40. Therefore, the metal layer 20 and the release film 18 are less likely to experience heat history when they are in contact. As a result, adhesion of the metal layer 20 and the release film 18 is suppressed.

Additionally, in step F, the heat-resistant polymer film 12 with the metal layer 20 peeled from the release film 18 is bonded to the inorganic substrate 40 using the silane coupling agent layer 42 as a bonding surface. First, the metal layer 20 (metal layer 20 exposed from the through hole 13) peeled off from the release film 18 is simply adhered to the silane coupling agent layer 42 with appropriate adhesion, and thereafter, the metal layer 20 is heated. Even if subjected to hysteresis, it is not strongly adhered to the inorganic substrate 40. In addition, the silane coupling agent layer 42 and the heat-resistant polymer film 12 are only adhered with an appropriate adhesion force, and thereafter, they are not firmly adhered to the inorganic substrate 40 even when subjected to heat history. Therefore, after step G of patterning the metal layer 20, the inorganic substrate 40 with the silane coupling agent layer 42 can be easily peeled from the heat-resistant polymer film 12, such as by pulling it off. That is, the inorganic substrate 40 can be easily peeled from the heat-resistant polymer film 12 using the silane coupling agent layer 42 and the heat-resistant polymer film 12 as an interface. Since the inorganic substrate 40 can be peeled off from the heat-resistant polymer film 12 by pulling it off, a peeling chemical solution for peeling off the inorganic substrate is attached to the patterned metal layer 20 (wiring layer 21) or plasma is applied. It cannot happen that things are investigated. As a result, the circuit board 60 can be peeled from the inorganic substrate 40 without damaging the circuit board 60 (patterned metal layer 20, etc.) formed on the inorganic substrate 40 as much as possible.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described examples, and the design can be appropriately changed within the range that satisfies the configuration of the present invention.

10: heat-resistant polymer film with double-sided protective film, 12: heat-resistant polymer film, 12b: second side, 12a: first side, 13: through hole, 14: first protective film, 16: second protective film, 18: release Film, 20: Metal layer, 21: Wiring layer (patterned metal layer), 30: Circuit board precursor with release film, 40: Inorganic substrate, 42: Silane coupling agent layer, 44: Adhesive layer, 46: Second heat-resistant polymer film, 48 : Through hole, 49: Second wiring layer, 50: Circuit board precursor with inorganic substrate, 52: Second wiring layer, 60: Circuit board.

Claims (5)

Process A of forming a through hole in a heat-resistant polymer film,
Process B of adhering a release film to the first side of the heat-resistant polymer film on which the through hole is formed,
Step C of forming a metal layer on the heat-resistant polymer film and on the release film in the through-hole from the second surface side of the heat-resistant polymer film on which the through-hole is formed,
After step C, step D of peeling the release film from the heat-resistant polymer film,
Process E of preparing an inorganic substrate having a silane coupling agent layer,
After step D, step F of bonding the inorganic substrate to the first surface of the heat-resistant polymer film after peeling off the release film, using the silane coupling agent layer as a bonding surface,
After step F, step G of patterning the metal layer, and
After step G, step H of peeling the inorganic substrate from the heat-resistant polymer film
A method of manufacturing a circuit board comprising: The method of manufacturing a circuit board according to claim 1, wherein the heat-resistant polymer film is a polyimide film. The method of manufacturing a circuit board according to claim 1 or 2, wherein the inorganic substrate is a glass plate, a ceramic plate, a semiconductor wafer, or a composite of two or more of these. A release film,
A heat-resistant polymer film having a through hole,
Provided with a metal layer,
The heat-resistant polymer film is formed on the release film,
A circuit board precursor with a release film, wherein the metal layer is formed on the heat-resistant polymer film and on the release film in the through hole. an inorganic substrate,
A silane coupling agent layer,
A heat-resistant polymer film having a through hole,
Provided with a metal layer,
The silane coupling agent layer is formed on the inorganic substrate,
The heat-resistant polymer film is formed on the silane coupling agent layer,
A circuit board precursor with an inorganic substrate, characterized in that the metal layer is formed on the heat-resistant polymer film and on the silane coupling agent layer in the through hole.