JP2006130877A - Film base material for wiring substrate, manufacturing method of film base material for wiring substrate, and flexible printed board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a film base material for a wiring substrate made of a thermosetting resin or a thermoplastic resin and suitable for a highly fine and high frequency application. <P>SOLUTION: The film base material 10 for the wiring substrate comprises a resin film 11 of a polyimide or a liquid crystal polymer (LCP), a siloxane polymer-containing polymer film 12 made by curing a coating film of an organic SOG solution applied on the resin film 11, and a metallic film 13 formed by soaking the polymer film 12 in a Ni-B electroless plating solution to form a plated underlayer. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a film substrate for a wiring board and the like, and more particularly to a film substrate for a wiring board suitable for high precision and / or high frequency applications.

  With the increase in speed and density of various electronic devices, higher functionality of the wiring board is required, and studies on high frequency compatibility and higher density are being actively conducted. In particular, the flexibility of the wiring board is indispensable for mobile phone applications and liquid crystal display applications accompanying the development of mobile devices, and so-called flexible printed circuit boards (hereinafter sometimes referred to as “flexible boards”) corresponding thereto. Is actively being developed.

The wiring rule of the flexible substrate currently mass-produced is about 50 μm to 100 μm as a line / space. Recently, fine etching using a thin copper foil, or so-called semi-growing that grows a plated wiring film in a resist pattern. High-definition wiring is formed by using the additive method. In general, since a drastic decrease in the copper foil, that is, the wiring thickness causes problems in mounting properties, the semi-additive method is considered to be the main measure.
Furthermore, the flatness of the pattern is important in terms of high frequency compatibility, and it is desirable that the unevenness at the interface with the substrate be as small as possible. In this sense, a semi-additive method that does not require the attachment of copper foil is advantageous and is being studied. In addition, polyimide has been conventionally used as a plastic film as a base material for a flexible substrate. Recently, a liquid crystal polymer (LCP) having a low hygroscopic property and an excellent insulating property has been studied for high-frequency applications (non-contained). (See Patent Document 1).

Fumihiko Matsuda, “Mounting Technology Trends for Flexible Wiring Boards-4. FPC for High Speed and High Frequency”, 36th Electronics Packaging Society Seminar, Japan Institute of Electronics Packaging, July 14, 2004, p. 36-51

  Incidentally, the semi-additive method has several problems from a practical viewpoint, and one of them is formation of a seed layer. That is, when performing pattern plating for wiring, it is necessary to form a seed layer on the flexible substrate film. At present, this seed layer is formed by a dry film forming method such as sputtering, which causes a reduction in process efficiency and high cost. Further, when sputtering a Cu film on a flexible substrate film such as polyimide, it is usually necessary to form a thin film such as Ni or Cr as an adhesive layer in order to ensure adhesion. In addition, an etching process in patterning is added, and in the case of Ni, since it is a magnetic metal element, there is a risk of hindrance in high frequency applications.

Such a problem related to the formation of the seed layer by the dry film forming method can be solved to some extent by adopting a wet method such as electroless plating. In other words, it is considered that the electroless plating increases the process efficiency and can directly form a seed layer such as a Cu film on the flexible substrate film.
However, the conventional electroless plating on a plastic film is not suitable for high-frequency applications as described above, because irregularities are formed on the surface of the plastic film by pretreatment and a plating layer is attached by a so-called anchor effect. For example, in the case of polyimide, the surface roughening treatment of the flexible substrate film is generally performed by a pretreatment agent called a conditioner.

  In particular, in the case of a liquid crystal polymer (LCP), the adhesion of a metal film to the liquid crystal polymer (LCP) is low even if any of a dry method such as sputtering and a wet method such as plating is adopted. It is difficult to form a seed layer on a polymer (LCP) film. For this reason, the wiring board using liquid crystal polymer (LCP) is limited to a copper foil pasting type, and the liquid crystal polymer (LCP) is high-definition for high-frequency applications even though the insulating property of the material itself is excellent. There is a problem that the form of use as a substrate is restricted.

  Thus, there is a demand for a film substrate for a wiring board in which the seed layer is formed by a simple and low-cost process while maintaining the flatness of the film surface, a method for producing the same, and a flexible printed circuit board. There is a demand for a flexible printed circuit board using LCP) as a base material and suitable for high-definition and high-frequency applications.

The present invention has been made to solve the technical problems described above.
That is, the objective of this invention is providing the film base material for wiring boards suitable for the high-definition and high frequency use which used the thermosetting resin or the thermoplastic resin for the base material.
Another object of the present invention is to provide a method for producing a film substrate for a wiring board by a simple and low-cost process.
Furthermore, another object of the present invention is to provide a flexible printed board suitable for high-definition and high-frequency applications using a liquid crystal polymer (LCP) or the like as a base material.

  For this purpose, according to the present invention, a resin film made of a thermosetting resin or a thermoplastic resin, a polymer film containing a siloxane polymer formed on at least one surface of the resin film, and the polymer film as an underlayer There is provided a film substrate for a wiring board comprising a metal film formed by plating.

In the film substrate for a wiring board to which the present invention is applied, if the siloxane polymer is a siloxane resin having a three-dimensional structure based on a siloxane bond, such a siloxane resin is similar to an inorganic silica thin film. High heat resistance and reflow resistance required for wiring boards.
Here, the polymer film preferably contains a siloxane polymer containing ultrafine silica particles, and adhesion to the resin film is improved.
Furthermore, the plating process is preferably an electroless plating process.
Moreover, it is preferable that the thermosetting resin which comprises a resin film is a polyimide resin. Furthermore, if the thermoplastic resin is a liquid crystal polymer, it is possible to form a film substrate for a wiring board excellent in high frequency.

  Next, when grasping the present invention from the category of the method, according to the present invention, a polymer film forming step of forming a polymer film containing a siloxane polymer on at least one surface of a resin film made of a thermosetting resin or a thermoplastic resin, There is provided a method for producing a film base material for a wiring board, comprising: using a polymer film formed by the polymer film forming step as a base layer, and a plating process step of forming a metal film on the polymer film by plating. Is done.

  Here, in the present invention, the polymer film forming step comprises applying a solution of a silane compound having a hydrolyzable group in the molecule to at least one surface of the resin film, and a siloxane resin mainly comprising a hydrolysis product of the silane compound. If the silane compound coated on the resin film is baked under appropriate conditions, a hydrolytic condensation reaction occurs, and a three-dimensional structure based on a siloxane bond (Si—O—Si) is formed. It is formed.

  In the polymer film forming step, the siloxane polymer is baked at a temperature lower than a predetermined baking temperature or in a shorter time than a predetermined baking time, and the siloxane polymer is heat-treated after the plating treatment step. The adhesion force with can be increased.

  In the plating step, the polymer film and the electroless plating solution are preferably brought into contact with each other. Here, it is preferable that the polymer film surface is subjected to an alkali treatment or a plasma treatment as a pretreatment of the plating treatment step.

  Furthermore, according to this invention, it is a flexible printed circuit board which has the wiring pattern formed on the film base material for wiring boards, Comprising: The film base material for wiring boards is a resin film which consists of a thermosetting resin or a thermoplastic resin And a polymer film containing a siloxane polymer formed on at least one surface of the resin film, and a metal film formed by electroless plating using the polymer film as a base layer, and the wiring pattern includes the metal film as a seed layer. A flexible printed circuit board characterized by being formed by electroplating is provided.

  ADVANTAGE OF THE INVENTION According to this invention, the film base material for wiring boards suitable for the high-definition and high frequency use which used the thermosetting resin or the thermoplastic resin for the base material is provided.

The best mode (embodiment) for carrying out the present invention will be described below in detail with reference to the accompanying drawings. In addition, this invention is not limited to this Embodiment, It can implement in various deformation | transformation within the range of the summary.
FIG. 1 is a diagram for explaining a wiring board film substrate to which the present embodiment is applied. FIG. 1 does not represent the actual size of the wiring board film base material.
A film substrate 10 for a wiring board shown in FIG. 1 includes a resin film 11 made of a thermosetting resin or a thermoplastic resin, a polymer film 12 containing a siloxane polymer formed on the resin film 11, and a polymer film 12 And a metal film 13 formed by plating using the base layer as a base layer.

(Resin film)
The thermosetting resin or thermoplastic resin constituting the resin film 11 is not particularly limited as long as it has insulating properties, and a known resin is used. Examples of such resins include thermosetting resins such as polyimide resins, epoxy resins, phenol resins, and unsaturated polyester resins; liquid crystal polymers (LCP), polyamide resins, polyphenylene ether resins, polyphenylene sulfide resins, and polyvinyl chloride resins. And thermoplastic resins such as polyethylene resins. Among these, as the thermosetting resin, a polyimide resin is preferable. Moreover, as a thermoplastic resin, a liquid crystal polymer (LCP) is preferable.

  Of the thermosetting resins, the polyimide resin may be any resin having an imide bond as a repeating unit in the molecule. For example, a polyimide resin obtained by polycondensation of aromatic tetracarboxylic dianhydride and diamine, aromatic Polyamic acid resin formed by polycondensation of aromatic tetracarboxylic dianhydride and diamine, etc., polyimide amic acid resin having imide portion and amic acid portion formed by polycondensation of aromatic tetracarboxylic dianhydride and diamine, etc. Can be mentioned.

  The aromatic tetracarboxylic dianhydride constituting the raw material of the polyimide resin is not particularly limited. For example, pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, 2,2 ′, 3,3′-benzophenone tetracarboxylic dianhydride, 2,3,3 ′, 4′-benzophenone tetracarboxylic dianhydride, naphthalene-2,3,6,7-tetracarboxylic dianhydride Anhydride, naphthalene-1,2,5,6-tetracarboxylic dianhydride, naphthalene-1,2,4,5-tetracarboxylic dianhydride, naphthalene-1,4,5,8-tetracarboxylic acid Dianhydride, naphthalene-1,2,6,7-tetracarboxylic dianhydride, 4,8-dimethyl-1,2,3,5,6,7-hexahydronaphthalene-1,2,5,6 -Tetracarbo Acid dianhydride, 4,8-dimethyl-1,2,3,5,6,7-hexahydronaphthalene-2,3,6,7-tetracarboxylic dianhydride, 2,6-dichloronaphthalene-1 , 4,5,8-tetracarboxylic dianhydride, 2,7-dichloronaphthalene-1,4,5,8-tetracarboxylic dianhydride, 2,3,6,7-tetrachloronaphthalene-1, 4,5,8-tetracarboxylic dianhydride, 1,4,5,8-tetrachloronaphthalene-2,3,6,7-tetracarboxylic dianhydride, 3,3 ′, 4,4′- Diphenyltetracarboxylic dianhydride, 2,2 ′, 3,3′-diphenyltetracarboxylic dianhydride, 2,3,3 ′, 4′-diphenyltetracarboxylic dianhydride, 3,3 ′, 4 , 4′-p-terphenyltetracarboxylic dianhydride, 2,2 ′, , 3′-p-terphenyltetracarboxylic dianhydride, 2,3,3 ′, 4′-p-terphenyltetracarboxylic dianhydride, 2,2-bis (2,3-dicarboxyphenyl) -Propane dianhydride, 2,2-bis (3,4-dicarboxyphenyl) -propane dianhydride, bis (2,3-dicarboxyphenyl) ether dianhydride, bis (3,4-dicarboxyphenyl) ) Ether dianhydride, bis (2,3-dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) methane dianhydride, bis (2,3-dicarboxyphenyl) sulfone dianhydride Bis (3,4-dicarboxyphenyl) sulfone dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride, 1,1-bis (3,4-dicarboxyphenyl) ethane Tan dianhydride, perylene-2,3,8,9-tetracarboxylic dianhydride, perylene-3,4,9,10-tetracarboxylic dianhydride, perylene-4,5,10,11-tetra Carboxylic dianhydride, perylene-5,6,11,12-tetracarboxylic dianhydride, phenanthrene-1,2,7,8-tetracarboxylic dianhydride, phenanthrene-1,2,6,7- Tetracarboxylic dianhydride, phenanthrene-1,2,9,10-tetracarboxylic dianhydride, cyclopentane-1,2,3,4-tetracarboxylic dianhydride, pyrazine-2,3,5 6-tetracarboxylic dianhydride, pyrrolidine-2,3,4,5-tetracarboxylic dianhydride, thiophene-2,3,4,5-tetracarboxylic dianhydride, 4,4'-oxydiphthalic acid Dianhydride, etc. It is.

  Specific examples of the diamine include, for example, m-phenylenediamine, p-phenylenediamine, 4,4′-diaminodiphenylpropane, 4,4′-diaminodiphenylmethane, benzidine, 4,4′-diaminodiphenyl sulfide, 4,4 '-Diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 4,4'-diaminodiphenyl ether, 3,3'-diaminodiphenyl ether, 4,4'-diamino-p-terphenyl, 2,2-bis (3 -Aminophenoxyphenyl) propane, 2,2-bis (4-aminophenoxyphenyl) propane, 3,3-bis (3-aminophenoxyphenyl) sulfone, 4,4-bis (3-aminophenoxyphenyl) sulfone, 3 , 3-Bis (4-aminophenoxyphenyl) sulfone 4,4-bis (4-aminophenoxyphenyl) sulfone, 2,2-bis (3-aminophenoxyphenyl) hexafluoropropane, 2,2-bis (4-aminophenoxyphenyl) hexafluoropropane, 1,4- Bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 4,4- (p-phenylenediisopropylidene) bisaniline, 4,4- (m-phenylenediisopropylidene) bisaniline, 2,5-diaminophenol, 3,5-diaminophenol, 4,4 ′-(3,3′-dihydroxy) diaminobiphenyl, 4,4 ′-(2,2′-dihydroxy) diaminobiphenyl, 2,2 ′ -Bis (3-amino-4-hydroxyphenyl) hexafluoropropane, 3,3 ', 4,4'-bi Phenyltetraamine, 3,3 ′, 4,4′-tetraaminodiphenyl ether, 4,4 ′-(3,3′-dicarboxy) diphenylamine, 3,3′-dicarboxy-4,4′-diaminodiphenyl ether, etc. Of the aromatic diamine.

  Moreover, diaminosiloxane is mentioned as a diamine. Specific examples of the diaminosiloxane include, for example, ω, ω′-bis (2-aminoethyl) polydimethylsiloxane, ω, ω′-bis (3-aminopropyl) polydimethylsiloxane, ω, ω′-bis (4 -Aminophenyl) polydimethylsiloxane, ω, ω'-bis (3-aminopropyl) polydiphenylsiloxane, ω, ω'-bis (3-aminopropyl) polymethylphenylsiloxane and the like.

Among the thermoplastic resins, as the liquid crystal polymer (LCP), various conventionally known liquid crystal polymers (LCP) such as known thermotropic liquid crystals can be used. Examples of the thermotropic liquid crystal polymer include liquid crystalline polyesters, liquid crystalline polyester imides, and the like, specifically, (all) aromatic polyesters, polyester amides, polyester carbonates, and the like. Among these, liquid crystalline polyester is preferable.
Representative examples of the monomer constituting the thermotropic liquid crystal polyester include (a) at least one aromatic dicarboxylic acid, (b) at least one aromatic hydroxycarboxylic acid compound, and (c) an aromatic diol compound. At least one, (d-1) aromatic dithiol, (d-2) aromatic thiophenol, and (d-3) aromatic thiol carboxylic acid compound, (e) aromatic hydroxylamine and aromatic diamine Examples include at least one type of compound. These are usually (A) and (D); (A) and (D); (A), (B) and (C); (A), (B) and (E); or (A), ( (B), (c), (e) and the like are combined.

  (A) As an aromatic dicarboxylic acid type compound, for example, terephthalic acid, 4,4′-biphenyldicarboxylic acid, 4,4′-triphenyldicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid Acid, 2,7-naphthalenedicarboxylic acid, diphenyl ether-4,4′-dicarboxylic acid, diphenoxyethane-4,4′-dicarboxylic acid, diphenoxybutane-4,4′-dicarboxylic acid, diphenylethane-4,4 '-Dicarboxylic acid, isophthalic acid, diphenyl ether-3,3'-dicarboxylic acid, diphenoxyethane-3,3'-dicarboxylic acid, diphenylethane-3,3'-dicarboxylic acid, 1,6-naphthalenedicarboxylic acid, etc. Aromatic dicarboxylic acids; chloroterephthalic acid, dichloroterephthalic acid, bromoterephthalic acid, Le terephthalic acid, dimethyl terephthalate, ethyl terephthalic acid, methoxy terephthalic acid, alkyl aromatic dicarboxylic acids such as ethoxy terephthalic acid, alkoxy- or halogen-substituted products thereof.

  (B) Examples of aromatic hydroxycarboxylic acid compounds include aromatic hydroxycarboxylic acids such as 4-hydroxybenzoic acid, 3-hydroxybenzoic acid, 6-hydroxy-2-naphthoic acid, and 6-hydroxy-1-naphthoic acid. Acid; 3-methyl-4-hydroxybenzoic acid, 3,5-dimethyl-4-hydroxybenzoic acid, 2,6-dimethyl-4-hydroxybenzoic acid, 3-methoxy-4-hydroxybenzoic acid, 3,5- Dimethoxy-4-hydroxybenzoic acid, 6-hydroxy-5-methyl-2-naphthoic acid, 6-hydroxy-5-methoxy-2-naphthoic acid, 2-chloro-4-hydroxybenzoic acid, 3-chloro-4- Hydroxybenzoic acid, 2,3-dichloro-4-hydroxybenzoic acid, 3,5-dichloro-4-hydroxybenzoic acid, 2,5-dichloro- -Hydroxybenzoic acid, 3-bromo-4-hydroxybenzoic acid, 6-hydroxy-5-chloro-2-naphthoic acid, 6-hydroxy-7-chloro-2-naphthoic acid, 6-hydroxy-5,7-dichloro Examples include alkyl, alkoxy or halogen substituted products of aromatic hydroxycarboxylic acids such as -2-naphthoic acid.

  (C) As aromatic diols, for example, 4,4′-dihydroxybiphenyl, 3,3′-dihydroxybiphenyl, 4,4′-dihydroxyterphenyl, hydroquinone, resorcin, 2,6-naphthalenediol, 4,4 '-Dihydroxydiphenyl ether, bis (4-hydroxyphenoxy) ethane, 3,3'-dihydroxydiphenyl ether, 1,6-naphthalenediol, 2,2-bis (4-hydroxyphenyl) propane, bis (4-hydroxyphenyl) methane Aromatic diols such as chlorohydroquinone, methylhydroquinone, tert-butylhydroquinone, phenylhydroquinone, methoxyhydroquinone, phenoxyhydroquinone, 4-chlororesorcin, 4-methylresorcin Alkyl, alkoxy or halogen-substituted derivatives thereof.

(D-1) Examples of aromatic dithiols include benzene-1,4-dithiol, benzene-1,3-dithiol, 2,6-naphthalene-dithiol, 2,7-naphthalene-dithiol, and the like.
(D-2) Examples of aromatic thiophenol include 4-mercaptophenol, 3-mercaptophenol, 6-mercaptophenol and the like.
(D-3) Examples of the aromatic thiol carboxylic acid include 4-mercaptobenzoic acid, 3-mercaptobenzoic acid, 6-mercapto-2-naphthoic acid, 7-mercapto-2-naphthoic acid and the like.

  (E) As an aromatic hydroxylamine or aromatic diamine compound, for example, 4-aminophenol, N-methyl-4-aminophenol, 1,4-phenylenediamine, N-methyl-1,4-phenylenediamine, N, N′-dimethyl-1,4-phenylenediamine, 3-aminophenol, 3-methyl-4-aminophenol, 2-chloro-4-aminophenol, 4-amino-1-naphthol, 4-amino-4 '-Hydroxybiphenyl, 4-amino-4'-hydroxydiphenyl ether, 4-amino-4'-hydroxydiphenylmethane, 4-amino-4'-hydroxydiphenyl sulfide, 4,4'-diaminophenyl sulfide (thiodianiline), 4, 4'-diaminodiphenyl sulfone, 2,5-diaminotoluene , 4,4' ethylene dianiline, 4,4'-diaminodiphenyl diphenoxyethane, 4,4'-diaminodiphenylmethane (methylenedianiline), 4,4'-diaminodiphenyl ether (oxydianiline), and the like.

  A liquid crystal polymer (LCP) is formed as a polymer by various combinations of these raw material compounds. For example, the thermotropic liquid crystal polyester can be produced from the above-described monomers by various ester forming methods such as a melt acidosis method and a slurry polymerization method. The molecular weight of the thermotropic liquid crystal polyester is usually 2,000 to 200,000, preferably 10,000 to 100,000. The liquid crystal polymer (LCP) may be blended with a thermoplastic resin such as polyarylate, polyphenylene sulfide, polyphenylene ether, polyether ether ketone, polyamide, etc., as long as the physical properties of the resin film 11 are not impaired. .

  Although the thickness of the resin film 11 is not specifically limited, Usually, 5 micrometers-200 micrometers, Preferably, they are 10 micrometers-150 micrometers, Most preferably, they are 20 micrometers-100 micrometers. When the thickness of the resin film 11 is too small, the function as a support tends to be lowered. If the thickness of the resin film 11 is excessively large, the flexibility tends to be lowered and it is not suitable for a flexible substrate.

(Polymer film)
The polymer film 12 of the wiring board film substrate 10 to which this exemplary embodiment is applied is made of, for example, an insulating siloxane resin mainly composed of a hydrolysis product of a silane compound having a hydrolyzable group in the molecule. Composed. Such a siloxane resin can be formed, for example, by using a coating type insulating film called SOG (Spin on Glass) for forming an interlayer insulating film such as a silicon device. Examples of SOG (Spin on Glass) include an inorganic silanol system, an organic silanol system, a hybrid silanol system using a combination of an inorganic silanol system and an organic silanol system, a silicon ladder system, and a polysilazane system. SOG (Spin on Glass) is coated on the resin film 11 and then fired under appropriate conditions to cause a hydrolytic condensation reaction to form a three-dimensional structure by siloxane bonds (Si—O—Si). .

Examples of the hydrolyzable group in the silane compound include an alkoxy group, a halogen atom, an acetoxy group, and an isocyanate group. In these, an alkoxy group is preferable.
As a specific example of an alkoxysilane compound having an alkoxy group as a hydrolyzable group in the molecule, examples of the alkoxysilane compound having four alkoxy groups in the molecule include tetramethoxysilane, tetraethoxysilane, tetra-n- Examples include propoxysilane, tetra-iso-propoxysilane, tetra-n-butoxysilane, tetra-sec-butoxysilane, tetra-tert-butoxysilane, and tetraphenoxysilane.

  Examples of the alkoxysilane compound having three alkoxy groups in the molecule include methyltrimethoxysilane, methyltriethoxysilane, methyltri-n-propoxysilane, methyltri-iso-propoxysilane, methyltri-n-butoxysilane, methyltrimethoxysilane. -Sec-butoxysilane, methyltri-tert-butoxysilane, methyltriphenoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, ethyltri-n-propoxysilane, ethyltri-iso-propoxysilane, ethyltri-n-butoxysilane, ethyltri -Sec-butoxysilane, ethyltri-tert-butoxysilane, ethyltriphenoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, n-propyl Ri-n-propoxysilane, n-propyltri-iso-propoxysilane, n-propyltri-n-butoxysilane, n-propyltri-sec-butoxysilane, n-propyltri-tert-butoxysilane, n-propyl Triphenoxysilane, i-propyltrimethoxysilane, i-propyltriethoxysilane, i-propyltri-n-propoxysilane, i-propyltri-iso-propoxysilane, i-propyltri-n-butoxysilane, i- Propyltri-sec-butoxysilane, i-propyltri-tert-butoxysilane, i-propyltriphenoxysilane, n-butyltrimethoxysilane, n-butyltriethoxysilane, n-butyltri-n-propoxysilane, n- Butyltri-iso-propoxy Silane, n-butyltri-n-butoxysilane, n-butyltri-sec-butoxysilane, n-butyltri-tert-butoxysilane, n-butyltriphenoxysilane, sec-butyltrimethoxysilane, sec-butyl-i-tri Ethoxysilane, sec-butyl-tri-n-propoxysilane, sec-butyl-tri-iso-propoxysilane, sec-butyl-tri-n-butoxysilane, sec-butyl-tri-sec-butoxysilane, sec-butyl -Tri-tert-butoxysilane, sec-butyl-triphenoxysilane, t-butyltrimethoxysilane, t-butyltriethoxysilane, t-butyltri-n-propoxysilane, t-butyltri-iso-propoxysilane, t- Butyltri-n-butoxy Silane, t-butyltri-sec-butoxysilane, t-butyltri-tert-butoxysilane, t-butyltriphenoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, phenyltri-n-propoxysilane, phenyltri-iso- Examples include trialkoxysilane compounds such as propoxysilane, phenyltri-n-butoxysilane, phenyltri-sec-butoxysilane, phenyltri-tert-butoxysilane, and phenyltriphenoxysilane.

  Examples of the alkoxysilane compound having two alkoxy groups in the molecule include dimethyldimethoxysilane, dimethyldiethoxysilane, dimethyl-di-n-propoxysilane, dimethyl-di-iso-propoxysilane, and dimethyl-di-n. -Butoxysilane, dimethyl-di-sec-butoxysilane, dimethyl-di-tert-butoxysilane, dimethyldiphenoxysilane, diethyldimethoxysilane, diethyldiethoxysilane, diethyl-di-n-propoxysilane, diethyl-di-iso -Propoxysilane, diethyl-di-n-butoxysilane, diethyl-di-sec-butoxysilane, diethyl-di-tert-butoxysilane, diethyldiphenoxysilane, di-n-propyldimethoxysilane, di-n-propyldiet Sisilane, di-n-propyl-di-n-propoxysilane, di-n-propyl-di-iso-propoxysilane, di-n-propyl-di-n-butoxysilane, di-n-propyl-di-sec -Butoxysilane, di-n-propyl-di-tert-butoxysilane, di-n-propyl-di-phenoxysilane, di-iso-propyldimethoxysilane, di-iso-propyldiethoxysilane, di-iso-propyl Di-n-propoxysilane, di-iso-propyl-di-iso-propoxysilane, di-iso-propyl-di-n-butoxysilane, di-iso-propyl-di-sec-butoxysilane, di-iso -Propyl-di-tert-butoxysilane, di-iso-propyl-di-phenoxysilane, di-n-butyldimethyl Xysilane, di-n-butyldiethoxysilane, di-n-butyl-di-n-propoxysilane, di-n-butyl-di-iso-propoxysilane, di-n-butyl-di-n-butoxysilane, Di-n-butyl-di-sec-butoxysilane, di-n-butyl-di-tert-butoxysilane, di-n-butyl-di-phenoxysilane, di-sec-butyldimethoxysilane, di-sec-butyl Diethoxysilane, di-sec-butyl-di-n-propoxysilane, di-sec-butyl-di-iso-propoxysilane, di-sec-butyl-di-n-butoxysilane, di-sec-butyl-di -Sec-butoxysilane, di-sec-butyl-di-tert-butoxysilane, di-sec-butyl-di-phenoxysilane, di-tert- Butyldimethoxysilane, di-tert-butyldiethoxysilane, di-tert-butyl-di-n-propoxysilane, di-tert-butyl-di-iso-propoxysilane, di-tert-butyl-di-n-butoxy Silane, di-tert-butyl-di-sec-butoxysilane, di-tert-butyl-di-tert-butoxysilane, di-tert-butyl-di-phenoxysilane, diphenyldimethoxysilane, diphenyl-di-ethoxysilane, Diphenyl-di-n-propoxysilane, diphenyl-di-iso-propoxysilane, diphenyl-di-n-butoxysilane, diphenyl-di-sec-butoxysilane, diphenyl-di-tert-butoxysilane, diphenyldiphenoxysilane, Divinyltrimethoxysila Γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-trifluoropropyltrimethoxysilane, γ-trifluoro And propyltriethoxysilane. These may be used alone or in combination of two or more.

  Among such alkoxysilane compounds, tetraalkoxysilanes such as tetramethoxysilane and tetraethoxysilane; alkyltrialkoxysilanes such as methyltrimethoxysilane and methyltriethoxysilane; dialkyls such as dimethyldiethoxysilane and dimethyldimethoxysilane Dialkoxysilane is preferred.

  Examples of the compound (halogenated silane) in which the hydrolyzable group is a halogen atom (halogen group) include those in which the alkoxy group in the alkoxysilane molecule described above is substituted with a halogen atom. Examples of the compound (acetoxysilane) in which the hydrolyzable group is an acetoxy group include those in which the alkoxy group in the alkoxysilane molecule described above is substituted with an acetoxy group. Moreover, as a compound (isocyanate silane) whose hydrolyzable group is an isocyanate group, the thing by which the alkoxy group in the alkoxysilane molecule mentioned above was substituted by the isocyanate group is mentioned.

  As a catalyst for promoting the hydrolysis and condensation reaction of a silane compound having a hydrolyzable group in the molecule, formic acid, maleic acid, fumaric acid, acetic acid, propionic acid, butanoic acid, pentanoic acid, hexanoic acid, heptanoic acid, Octanoic acid, nonanoic acid, decanoic acid, oxalic acid, adipic acid, sebacic acid, butyric acid, oleic acid, stearic acid, linoleic acid, linolenic acid, salicylic acid, benzoic acid, p-aminobenzoic acid, p-toluenesulfonic acid, phthalate Organic acids such as acid, sulfonic acid, tartaric acid, and trifluoromethanesulfonic acid; inorganic acids such as hydrochloric acid, phosphoric acid, nitric acid, boric acid, sulfuric acid, and hydrofluoric acid can be used. The amount of the catalyst used is usually in the range of 0.0001 mol to 1 mol with respect to 1 mol of the silane compound having a hydrolyzable group in the molecule.

  By adding ultrafine silica particles to SOG (Spin on Glass), adhesion between the resin film 11 and the polymer film 12 can be enhanced. Such silica particles preferably have an average particle diameter in the range of 4 nm to 200 nm, more preferably 5 nm to 100 nm. The method for producing silica particles is not particularly limited as long as the average particle diameter is in the above-described range, and a conventionally known method can be adopted.

  The thickness of the polymer film 12 is not particularly limited, but is usually 0.05 μm to 5 μm, preferably 0.1 μm to 2 μm, and particularly preferably 0.1 μm to 0.5 μm. When the thickness of the polymer film 12 is excessively small, the adhesion improving effect tends to decrease. When the thickness of the polymer film 12 is excessively large, there is a tendency that the film surface is disturbed or the end portion is peeled off.

The SOG (Spin on Glass) applied on the resin film 11 includes a solvent that dissolves the silane compound described above. Examples of such solvents include alcohol solvents, ketone solvents, ether solvents, ester solvents, and the like.
Examples of alcohol solvents include methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, sec-butanol, t-butanol, n-pentanol, i-pentanol, and 2-methylbutanol. , Sec-pentanol, t-pentanol, 3-methoxybutanol, n-hexanol, 2-methylpentanol, sec-hexanol, 2-ethylbutanol, sec-heptanol, n-octanol, 2-ethylhexanol, sec- Octanol, n-nonyl alcohol, n-decanol, sec-undecyl alcohol, trimethylnonyl alcohol, sec-tetradecyl alcohol, sec-heptadecyl alcohol, phenol, cyclohexanol, methylcyclohexa Lumpur, benzyl alcohol, ethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, diethylene glycol, dipropylene glycol, triethylene glycol, tripropylene glycol, and the like.

  Examples of the ketone solvent include acetone, methyl ethyl ketone, methyl-n-propyl ketone, methyl-n-butyl ketone, methyl-i-butyl ketone, methyl-n-pentyl ketone, methyl-n-hexyl ketone, diethyl ketone, di- Examples include i-butyl ketone, trimethylnonanone, cyclohexanone, cyclopentanone, methylcyclohexanone, 2,4-pentanedione, acetonylacetone, diacetone alcohol, acetophenone, and γ-butyrolactone.

  Examples of ether solvents include ethyl ether, i-propyl ether, n-butyl ether, n-hexyl ether, 2-ethylhexyl ether, ethylene oxide, 1,2-propylene oxide, dioxolane, 4-methyldioxolane, dioxane, dimethyldioxane. , Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol diethyl ether, ethylene glycol mono-n-hexyl ether, ethylene glycol monophenyl ether, ethylene glycol mono-2-ethylbutyl ether, ethylene glycol dibutyl ether, diethylene glycol monoethyl ether , Diethylene glycol diethyl ether, diethylene glycol diethyl ether, diethylene Recall mono-n-butyl ether, diethylene glycol di-n-butyl ether, diethylene glycol mono-n-hexyl ether, ethoxytriglycol, tetraethylene glycol di-n-butyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl Examples include ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, tripropylene glycol monomethyl ether, tetrahydrofuran, and 2-methyltetrahydrofuran.

  Examples of ester solvents include methyl acetate, ethyl acetate, n-propyl acetate, i-propyl acetate, n-butyl acetate, i-butyl acetate, sec-butyl acetate, n-pentyl acetate, sec-pentyl acetate, and acetic acid. 3-methoxybutyl, methylpentyl acetate, 2-ethylbutyl acetate, 2-ethylhexyl acetate, benzyl acetate, cyclohexyl acetate, methyl cyclohexyl acetate, nonyl acetate, γ-butyrolactone, γ-valerolactone, methyl acetoacetate, ethyl acetoacetate, acetic acid Ethylene glycol monomethyl ether, acetate ethylene glycol monoethyl ether, acetate diethylene glycol monomethyl ether, acetate diethylene glycol monoethyl ether, acetate diethylene glycol mono-n-butyl ether, propylene glycol acetate Monoethyl ether, propylene glycol monopropyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, glycol diacetate, methoxytriglycol acetate, ethyl propionate, n-butyl propionate, i-amyl propionate , Diethyl oxalate, di-n-butyl oxalate, methyl lactate, ethyl lactate, n-butyl lactate, n-amyl lactate and the like.

  Furthermore, solvents such as acetonitrile, N, N-dimethylformamide, N, N-dimethylacetamide, N, N-dimethylsulfoxide and the like can be mentioned. These may be used alone or in combination of two or more.

(Metal film)
The metal film 13 of the wiring board film substrate 10 to which the present exemplary embodiment is applied is formed by plating using the polymer film 12 as an underlayer. The plating process is preferably an electroless plating process. As the electroless plating solution used for the electroless plating treatment, for example, a liquid containing metal ions such as copper, nickel, palladium, gold, platinum, rhodium or the like is preferably used. The electroless plating solution usually contains a water-soluble metal salt of the above metal ions, a reducing agent such as sodium hypophosphite, hydrazine, or sodium borohydride, and a complexing agent such as sodium acetate, phenylenediamine, or sodium potassium tartrate. In general, it is commercially available as an electroless plating solution and can be obtained easily and inexpensively. Among these electroless plating solutions, those containing copper, nickel or alloys thereof as metal ions are preferable.

  Examples of such an electroless plating solution include a Ni-B electroless plating solution, a Ni-P electroless plating solution, a Ni-Cu-P electroless plating solution, and a Cu electroless plating solution. It is done. The Ni-B electroless plating solution contains nickel sulfate, a complexing agent, and a boron-containing organic reducing agent, and 2,2′-thiodiethanol, thiodiglycolic acid, etc. Is included. Ni-P-based electroless plating solutions are nickel salts such as nickel sulfate, nickel chloride and nickel carbonate; complexing agents such as citric acid, malic acid and succinic acid; reductions such as hypophosphorous acid and sodium hypophosphite Agent: Contains water-soluble compounds such as iron, tungsten, molybdenum, and chromium, and further contains known stabilizers as necessary. Examples of water-soluble compounds include water-soluble iron compounds such as ferrous sulfate, ferrous chloride, and ferrous ammonium sulfate; water-soluble tungsten compounds such as sodium tungstate, potassium tungstate, and ammonium tungstate; sodium molybdate, Examples thereof include water-soluble molybdenum compounds such as ammonium molybdate and molybdenum chloride; water-soluble chromium compounds such as chromium chloride, chromium bromide and chromium sulfate. These water-soluble compounds can be used singly or in combination of two or more. About each component compounding quantity, what is necessary is just to adjust suitably in the range which can form the electroless nickel multicomponent alloy plating film of the composition mentioned above.

  The Ni—Cu—P-based electroless plating solution contains a nickel salt such as nickel sulfate, a copper salt such as copper sulfate, a reducing agent such as sodium phosphinate, and a complexing agent such as trisodium citrate as main components. Cu-based electroless plating solutions include cupric salts such as copper sulfate, copper chloride, and copper oxide; copper complexing agents such as ethylenediaminetetraacetic acid or its salts (sodium salt, potassium salt, etc.), Rochelle salt; Contains a reducing agent. Furthermore, As compounds such as arsenic trichloride, arsenic triacetate, arsenic acid, diarsenic trioxide, triphenylarsenic dihydroxide, and arsanilic acid; antimony trioxide, antimony pentoxide, antimony chloride, tartar, shu Sb compounds such as potassium antimony acid, hexafluoroantimonate, hexachloroantimonate; Bi compounds such as bismuth nitrate, bismuth hydroxide, bismuth oxalate, bismuth acetate, bismuth borate, bismuth oxide; beryllium sulfate, beryllium chloride , Beryllium nitrate, beryllium acetate, beryllium bromide, sodium beryllate, beryllium oxalate, and beryllium fluoride.

  As a method of bringing the polymer film 12 into contact with the electroless plating solution, it is preferable to immerse the polymer film 12 together with the resin film 11 in the electroless plating solution. The temperature at which the electroless plating solution and the polymer film 12 are brought into contact is preferably 15 ° C to 120 ° C, more preferably 25 ° C to 85 ° C. The contact time is, for example, 1 minute to 16 hours, and preferably about 10 minutes to 60 minutes.

  The thickness of the metal film 13 is not particularly limited, but is usually 0.05 μm to 2 μm, preferably 0.1 μm to 1 μm, and particularly preferably 0.1 μm to 0.5 μm. If the thickness of the metal film 13 is excessively small, the conductivity is lowered, and the film does not serve as a power feeding layer and the film tends to be non-uniform. When the thickness of the metal film 13 is excessively large, the density of the film is lowered and the strength tends to be lowered.

Next, the manufacturing method of the film base material 10 for wiring boards is demonstrated.
FIG. 2 is a diagram for explaining a method for producing the wiring board film base material 10 to which the exemplary embodiment is applied. FIG. 2 does not represent the actual size of the wiring board film base material 10.
First, as shown in FIG. 2A, after preparing the resin film 11 (preparation of the resin film), as shown in FIG. 2B, SOG (Spin containing an alkoxysilane compound on the resin film 11 is prepared. on Glass) solution is applied to form the SOG film 121 (SOG application). Examples of the coating method include spin coating, dipping, roll coating, blade coating, applicator coating, bar coating, and screen printing. For example, in the case of spin coating, the SOG film 121 is formed by spin-coating the SOG solution on the resin film 11 at a speed of 500 to 5000 revolutions / minute. Next, as shown in FIG.2 (c), the resin film 11 is heated with a hotplate etc. in the range of 50 degreeC-500 degreeC, the solvent in the SOG film 121 is dried, and the SOG film 121 is baked, A polymer film 12 made of a cured siloxane resin is formed (firing). The polymer film 12 has a three-dimensional structure of siloxane bonds (Si—O—Si) generated by the hydrolysis condensation reaction of the alkoxysilane compound. Firing is preferably performed in an inert atmosphere such as N ₂ , Ar, or He. In this case, the oxygen concentration is preferably 1000 ppm or less.

  Subsequently, as shown in FIG. 2D, an electroless plating process is performed using the polymer film 12 on the resin film 11 as a base layer, and a plating film 131 is formed on the polymer film 12 (electroless plating). As a pretreatment for the electroless plating treatment, it is usually preferable to subject the surface of the polymer film 12 to a dry treatment such as a plasma treatment or an alkali treatment in addition to a wet treatment such as pickling or rinsing. By such pretreatment, a part of the siloxane bond (Si—O—Si) on the surface of the polymer film 12 is cut, and a state similar to a so-called dangling bond is generated, and the bondability between the polymer film 12 and the plating film 131 is generated. Is expected to increase.

  Here, in FIG. 2C, the SOG film 121 is baked under mild conditions, that is, at a lower temperature or in a shorter time than the original baking conditions, and a siloxane bond (Si—O—Si) is formed in the polymer film 12. It is preferable to perform the electroless plating process in FIG. 2 (d) while the three-dimensional structure of FIG. By leaving the three-dimensional structure of the siloxane bond (Si—O—Si) incompletely formed in the polymer film 12, a portion where no siloxane bond is chemically formed and the plating film 131 Thus, the adhesion of the plating film 131 to the polymer film 12 can be enhanced.

  Next, as shown in FIG. 2 (e), the resin film 11 is heat-treated to promote the reaction of siloxane bonds (Si—O—Si) in the polymer film 12, and the surface of the resin film 11 is chemically and thermally heated. A film substrate 10 for a wiring board having a polymer film 12 made of a siloxane resin whose stability is improved both electrically and electrically and a metal film 13 formed on the surface of the polymer film 12 is prepared (heat treatment). The conditions for the heat treatment are appropriately selected depending on the types of the resin film 11 and the polymer film 12, but are usually performed at a temperature lower than the heat resistance temperature of the resin material used for the resin film 11. For example, when liquid crystal polymer (LCP) is used as the resin film 11 and the polymer film 12 is formed using a commercially available SOG solution, heat treatment is performed at a temperature of 200 ° C. for about 30 minutes.

  By performing the heat treatment in FIG. 2E, the adhesion between the polymer film 12 and the resin film 11 is increased. Moreover, the siloxane resin which comprises the polymer film 12 shows high heat resistance like an inorganic silica thin film, and has reflow resistance required for a wiring board. Furthermore, the hygroscopicity is low, and electrical properties such as insulating properties are stable. For this reason, when the resin film 11 is formed using a liquid crystal polymer (LCP), the high frequency suitability of the liquid crystal polymer (LCP) is not impaired.

Next, the flexible printed circuit board will be described.
FIG. 3 is a diagram for explaining a flexible printed circuit board to which the present embodiment is applied. FIG. 3 does not represent the actual size of the flexible printed circuit board.
The flexible printed circuit board 20 shown in FIG. 3 forms a wiring pattern by a semi-additive method in which electroplating is performed using the metal film 13 of the wiring board film base material 10 shown in FIG. 1 as a seed layer. Thus, it is manufactured by performing normal processes such as electrode terminal formation and coverlay provision. The flexible printed circuit board 20 includes a resin film 11 made of a thermosetting resin or a thermoplastic resin, a polymer film 12 containing a siloxane polymer formed on the resin film 11, and a circuit pattern 16 formed on the polymer film 12. It has. As will be described later, the circuit pattern 16 includes a metal film 13 formed by plating using the polymer film 12 as an underlayer, and a plated layer 15 formed by electroplating using the metal film 13 as a seed layer. Yes. As will be described later, the metal film 13 has a portion where the plating layer 15 is not formed is removed by an etching process performed using the plating layer 15 as an etching mask after the electroplating process.

Next, a method for producing a flexible printed board will be described.
FIG. 4 is a diagram for explaining a method for manufacturing the flexible printed circuit board 20 to which the present exemplary embodiment is applied. FIG. 4 does not represent the actual size of the flexible printed circuit board 20.
After preparing the wiring board film base material 10 (preparation of the wiring board film base material) as shown in FIG. 4A, as shown in FIG. On the metal film 13, for example, a positive photoresist is applied to form a resist film 14 (photoresist application). Examples of the coating method include spin coating, dipping, roll coating, blade coating, applicator coating, bar coating, and screen printing.

  Next, as shown in FIG. 4C, the portion of the photoresist in which the circuit pattern of the resist film 14 is to be formed is removed by photolithography (photolithography). That is, a latent image of a circuit pattern is formed on the resist film 14 using an exposure apparatus (not shown), and development is performed to remove a portion of the resist film 14 where the circuit pattern is to be formed, and to cope with that portion. The metal film 13 to be exposed is exposed. Subsequently, as shown in FIG. 4D, electroplating is performed using the exposed portion of the metal film 13 as a feeding electrode, and a plating layer 15 is formed in a portion where a circuit pattern is to be formed (electroplating process). A known method can be applied to the electroplating, and examples thereof include copper sulfate plating, copper cyanide plating, and copper pyrophosphate plating. Among these, copper sulfate plating is preferable from the viewpoint of handleability of plating solution, productivity, and film characteristics.

Next, as shown in FIG. 4E, the photoresist is removed by using, for example, a ketone-based stripping solution such as acetone to expose the portion of the metal film 13 where the circuit pattern is to be formed (resist removal). ). Subsequently, as shown in FIG. 4F, etching is performed to remove the unnecessary metal film 13 where the circuit pattern is to be formed, and the flexible printed circuit board 20 on which the circuit pattern is formed is manufactured.
As described above, the film substrate 10 for a wiring board to which the present embodiment is applied has the metal film 13 formed by electroless plating without passing through a step of forming a seed layer on the surface of the resin film 11 by sputtering or the like. Is formed. By using such a film substrate 10 for a wiring board, the process can be simplified, the need for an adhesive layer and a continuous process can be realized, and the flexible printed board 20 can be manufactured at low cost and with high functionality.

Hereinafter, the present embodiment will be described in more detail based on examples. Note that this embodiment is not limited to the examples.
(Tape peeling test)
An adhesive tape having a width of 15 mm and a length of 40 mm is applied to the plating film surface of the film base for a wiring board prepared in advance so that the adhesive surface has a length of 20 mm, and then the other end of the adhesive tape is pulled up, The peeling state at the time was visually observed.

Example 1
On a liquid crystal polymer film (made by Kuraray Co., Ltd .: Vecstar (registered trademark) CT) having a thickness of 50 μm, a polysiloxane solution (manufactured by Hitachi Chemical Co., Ltd .: coating material for interlayer insulating film HSG-7000) is applied by bar coating. Then, it was baked in the atmosphere at a temperature of 200 ° C. for 3 minutes to form a polymer film underlayer having a thickness of 400 nm. Next, as a pretreatment, the surface of the polymer film underlayer is subjected to an air plasma irradiation treatment, and then the liquid crystal polymer film is electrolessly plated (Okuno Pharmaceutical Co., Ltd .: electroless nickel-boron plating liquid top chemialloy B). Then, the substrate is immersed for 2 minutes at a temperature of 55 ° C., followed by a heat treatment at a temperature of 200 ° C. for 5 minutes in a nitrogen atmosphere to form a Ni plating film on the polymer film underlayer. A film substrate for a wiring board as a material was prepared.
The plating film of the wiring board film base material thus prepared had a glossy flat surface. In addition, as a result of the tape peeling test, peeling of the Ni plating film formed on the polymer film underlayer was not observed, and high adhesion strength was shown.

(Example 2)
A liquid crystal polymer film is obtained by performing the same operation as in Example 1 except that a hybrid type SOG of silica ultrafine filler and organic SOG (Catalyst Kasei Kogyo Co., Ltd .: Ceramate-LNT-025) is used as the polysiloxane solution. A film substrate for a wiring board was prepared using the above as a substrate.
The plating film of the wiring board film base material thus prepared had a glossy flat surface. In addition, as a result of the tape peeling test, peeling of the Ni plating film formed on the polymer film underlayer was not observed, and high adhesion strength was shown.

(Example 3)
A wiring board having a polyimide film as a base material, except that a polyimide film having a thickness of 50 μm (manufactured by Toray Industries, Inc .: Kapton (registered trademark)) is used instead of the liquid crystal polymer film. A film substrate was prepared.
The plating film of the wiring board film base material thus prepared had a glossy flat surface. In addition, as a result of the tape peeling test, peeling of the Ni plating film formed on the polymer film underlayer was not observed, and high adhesion strength was shown.

Example 4
As a pretreatment, instead of performing the atmospheric plasma irradiation treatment on the surface of the polymer film underlayer, the liquid crystal polymer film having the polymer film underlayer is immersed in an alkaline bath (1.3 mol NaOH) for 1 minute, The surface of the base layer was subjected to alkali treatment, and the other operations were performed in the same manner as in Example 1 to prepare a film substrate for a wiring board using a liquid crystal polymer film as a base material.
The plating film of the wiring board film base material thus prepared had a flat surface although it was slightly inferior to the case of Example 1. In addition, as a result of the tape peeling test, peeling of the Ni plating film formed on the polymer film underlayer was not observed, and high adhesion strength was shown.

It is a figure for demonstrating the film base material for wiring boards to which this Embodiment is applied. It is a figure for demonstrating the preparation methods of the film base material for wiring boards to which this Embodiment is applied. It is a figure for demonstrating the flexible printed circuit board to which this Embodiment is applied. It is a figure for demonstrating the manufacturing method of the flexible printed circuit board to which this Embodiment is applied.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Wiring board film base material, 11 ... Resin film, 12 ... Polymer film, 13 ... Metal film, 14 ... Resist film, 15 ... Plating layer, 16 ... Circuit pattern, 20 ... Flexible printed circuit board, 121 ... SOG film, 131 ... Plating film

Claims (16)

A resin film made of a thermosetting resin or a thermoplastic resin;
A polymer film containing a siloxane polymer formed on at least one side of the resin film;
A metal film formed by plating using the polymer film as a base layer;
A film substrate for a wiring board, comprising:   The film substrate for a wiring board according to claim 1, wherein the siloxane polymer is a siloxane resin having a three-dimensional structure based on a siloxane bond.   The film substrate for a wiring board according to claim 1, wherein the polymer film includes the siloxane polymer containing ultrafine silica particles.   The film substrate for a wiring board according to claim 1, wherein the plating process is an electroless plating process.   The film substrate for a wiring board according to claim 1, wherein the thermosetting resin is a polyimide resin.   The film substrate for a wiring board according to claim 1, wherein the thermoplastic resin is a liquid crystal polymer. A polymer film forming step of forming a polymer film containing a siloxane polymer on at least one surface of a resin film made of a thermosetting resin or a thermoplastic resin;
A plating process step of forming a metal film on the polymer film by a plating process using the polymer film formed by the polymer film forming step as a base layer;
A method for producing a film substrate for a wiring board, comprising:   In the polymer film forming step, a solution of a silane compound having a hydrolyzable group in a molecule is applied to at least one surface of the resin film to form a siloxane resin having a hydrolysis product of the silane compound as a main component. A method for producing a film substrate for a wiring board according to claim 7.   8. The polymer film forming step, wherein the siloxane polymer is baked at a temperature lower than a predetermined baking temperature or shorter than a predetermined baking time, and the siloxane polymer is heat-treated after the plating step. Of producing a film substrate for a wiring board.   8. The method for producing a film substrate for a wiring board according to claim 7, wherein the plating step comprises bringing the polymer film into contact with an electroless plating solution.   The method for producing a film substrate for a wiring board according to claim 7, wherein the polymer film surface is subjected to an alkali treatment before the plating step.   The method for producing a film substrate for a wiring board according to claim 7, wherein the polymer film surface is plasma-treated before the plating step.   The method for producing a film base material for a wiring board according to claim 7, wherein the thermosetting resin is a polyimide resin.   The method for producing a film substrate for a wiring board according to claim 7, wherein the thermoplastic resin is a liquid crystal polymer. A flexible printed board having a wiring pattern formed on a film substrate for a wiring board,
The film substrate for a wiring board includes a resin film made of a thermosetting resin or a thermoplastic resin, a polymer film containing a siloxane polymer formed on at least one surface of the resin film, and the polymer film as a base layer. A metal film formed by electrolytic plating,
The flexible printed circuit board, wherein the wiring pattern is formed by electroplating using the metal film as a seed layer.   The flexible printed circuit board according to claim 15, wherein the resin film is made of a liquid crystal polymer.

Images