JP2008270283A - Flexible printed wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a flexible printed wiring board excellent in through hole reliability and fine wiring formation property, and to provide a flexible printed wiring board allowing high-density mounting. <P>SOLUTION: A flexible printed wiring board excellent in through hole reliability and fine wiring formation property is provided by a flexible printed wiring board satisfying a relation (a)-(b)≤10 μm between the thickness (a) of wiring formed on the surface and the thickness (b) of a conductor layer at the opening of the through hole. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a flexible printed wiring board that achieves both through-hole reliability and fine wiring formation.

  The heat-resistant resin material is, for example, an electronic device component such as a printed wiring board (hereinafter also referred to as PWB), a flexible printed circuit board (hereinafter also referred to as FPC), or a tape automatic bonding (hereinafter also referred to as TAB) mounting board. Such a PWB, FPC, or TAB mounting substrate is a laminate composed of a copper / heat-resistant resin film in which copper is mainly formed as a metal layer on the surface of the heat-resistant resin film. Can be obtained by processing. A polyimide resin film is widely used as a heat resistant resin film because it has not only heat resistance but also excellent electrical insulation.

  The laminates as described above include a three-layer laminate in which a polyimide resin film and a metal coating are bonded via an adhesive, and a two-layer laminate in which a metal coating is directly formed on the polyimide resin film.

A flexible printed wiring board is manufactured as follows using the above-mentioned two-layer laminate or three-layer laminate. First, a through hole is formed in the laminate, a base metal layer is formed, electrolytic plating is formed, a resist pattern is formed, etching is performed, and wiring is formed by peeling the resist. This is called a subtractive construction method.

  As another method, through holes are formed in the laminate, a base metal layer is formed, a resist pattern is formed, electrolytic plating is formed, the resist is peeled off, and flash etching is performed to form a wiring. . This is called a semi-additive construction method.

  By the way, with recent increases in the density of electronic devices, flexible printed wiring boards having a narrow wiring width and wiring interval have been demanded. In order to form fine wiring satisfactorily, the thickness of the wiring is preferably as thin as possible. This is because when the thickness of the wiring is significantly larger than the wiring width, there is a problem that the wiring shape is defective due to side etching or the wiring is peeled off.

  On the other hand, the thickness of the conductor layer in the opening of the through hole is determined by the base metal layer and the thickness of the electrolytic plating. However, when this thickness is thin, there is a problem that the reliability of the through hole cannot be obtained.

  A flexible printed circuit board having a through-hole that can be manufactured safely and easily and a method for manufacturing the same are disclosed (for example, see Patent Document 1). However, there was no mention of through-hole reliability and fine wiring formability.

As described above, in order to obtain the fine wiring forming ability, it is necessary to reduce the thickness of the base metal layer and the electrolytic plating. However, in order to obtain the reliability of the through hole, the thickness of the base metal layer and the electrolytic plating is reduced. There was a need to do.
JP-A-9-232704

  Accordingly, an object of the present invention is to provide a flexible printed wiring board having excellent through-hole reliability and good fine wiring.

  As a result of intensive studies in view of the above problems, the present inventors have established a specific relationship between the thickness (a) of the wiring formed on the surface and the conductor layer thickness (b) of the through-hole opening. In some cases, the present inventors have found that the above problems can be solved, and have completed the present invention.

That is, the present invention
1) Flexible, characterized in that a relationship of (a) − (b) ≦ 10 μm is established between the thickness (a) of the wiring formed on the surface and the conductor layer thickness (b) of the through-hole opening. Printed wiring board.
2) The flexible printed wiring board according to 1), wherein a relationship of (a) − (b) ≦ 5 μm is established.
3) The flexible printed wiring board according to 1) or 2), wherein a relationship of (a) − (b) ≦ 0 is established.
4) The relationship of (a) / (c) ≦ 2.0 is established between the thickness (a) of the wiring formed on the surface and the wiring width (c). The flexible printed wiring board as described in any one of).
5) Wiring width (c) is 20 micrometers or less, The flexible printed wiring board as described in any one of 1) -4) characterized by the above-mentioned.
6) The relationship of (d) / (c) ≦ 2.0 is established between the wiring width (c) of the wiring formed on the surface and the wiring interval (d) 1) to 5) The flexible printed wiring board as described in any one of these.
7) A flexible printed wiring board, wherein wiring patterns having a wiring width (c) and a wiring interval (d) of 20 μm or less are formed on the surface.
8) Manufactured by a process including a process of forming a through hole in an insulating material, a process of forming a base metal layer, a process of performing electroplating, a process of forming a resist pattern, a process of etching, and a process of stripping the resist. The flexible printed wiring board according to any one of 1) to 7), wherein:
9) By a process including a process of forming a through hole in an insulating material, a process of forming a base metal layer, a process of forming a resist pattern, a process of performing electroplating, a process of stripping the resist, and a process of performing flash etching. The flexible printed wiring board according to any one of 1) to 7), which is manufactured.
10) The flexible printed wiring board according to 8) or 9), wherein the step of forming the base metal layer comprises electroless plating.
About.

  In the present invention, fine wiring can be formed satisfactorily by controlling the thickness (a) of the wiring formed on the surface and the conductor layer thickness (b) of the through-hole opening so that a specific relationship is established. Since the through hole reliability can be sufficiently secured, a flexible printed wiring board excellent in through hole reliability and fine wiring formability can be provided.

  One embodiment of the present invention will be described in detail below, but the present invention is not limited to the following description.

  The present invention is characterized in that a relationship of (a) − (b) ≦ 10 μm is established between the thickness (a) of the wiring formed on the surface and the conductor layer thickness (b) of the through-hole opening. The present invention relates to a flexible printed wiring board. By setting it as such a structure, the flexible printed wiring board excellent in through-hole reliability and fine wiring formation property can be provided. Each will be described in detail below.

<Thickness of wiring formed on surface (a)>
The thickness (a) of the wiring formed on the surface according to the present invention will be described.
(A) may consist of a single metal layer or a plurality of metal layers. As the configuration of (a), there are several types depending on the form of the material used for manufacturing the flexible printed wiring board of the present invention. Examples are given below.

  First, there is a case where (a) is made of a metal layer formed in the order of copper foil / electroless plating layer / electrolytic plating layer on a resin material. At this time, the material used for manufacture of the flexible printed wiring board of this invention is a laminated body which consists of resin material / copper foil or copper foil / resin material / copper foil.

  Moreover, the case where (a) consists of the metal layer formed in order of the dry-type plating layer / electroless-plating layer / electrolytic-plating layer on the resin material is mentioned. At this time, the material used for manufacturing the flexible printed wiring board of the present invention is a laminate comprising dry plating / resin material or dry plating / resin material / dry plating.

  Moreover, the case where (a) consists of the metal layer formed in order of the electroless plating layer / electrolytic plating layer on the resin material is mentioned. At this time, the material used for manufacturing the flexible printed wiring board of the present invention is a resin material.

  Moreover, the case where (a) consists of a metal layer formed only from the electroless plating layer on the resin material can be mentioned. At this time, the material used for manufacturing the flexible printed wiring board of the present invention is a resin material.

  Among them, (a) is not present on the resin material because of good productivity, no generation of pinholes, and control of the wiring thickness (a) by controlling the thickness of the electrolytic plating. It is preferable to consist of a metal layer formed in the order of electrolytic plating layer / electrolytic plating layer.

The copper foil which forms (a) is demonstrated.
About copper foil, there is no restriction | limiting in particular about the kind, Various copper foils, such as an electrolytic copper foil and a rolled copper foil, can be used. On the other hand, in order to satisfy (a) − (b) ≦ 10 μm, the thickness of the copper foil is preferably 10 μm or less, more preferably 9 μm or less, and particularly preferably 5 μm or less. preferable. When such a thin copper foil is used, there is a problem that it is cut or torn during transportation. Therefore, it is preferable to use a copper foil with a carrier such as copper or aluminum.

  The copper foil and the resin material may be bonded together via an adhesive layer, and the copper foil / resin material may be configured by applying a resin material solution to the copper foil and drying.

The electroless plating layer forming (a) will be described.
Examples of electroless plating include direct plating using carbon, palladium catalyst, organic manganese conductive film, etc., electroless copper plating, electroless nickel plating, electroless gold plating, electroless silver plating, electroless tin plating, etc. However, direct plating, electroless copper plating, and electroless nickel plating are preferable from the viewpoint of electrical characteristics such as migration resistance, and particularly preferable are direct plating and electroless copper. It is plating. When performing electroless plating, electroless plating may be performed directly, or electroless plating may be performed after processing such as desmearing.

  The dry plating layer forming (a) will be described. Examples of the dry plating include known methods such as vapor deposition, sputtering, and ion plating. In the case of dry plating, a copper film may be formed directly, or a method of forming a thin copper layer after forming a metal other than copper, such as chromium or nickel, may be used.

  The electroplating layer forming (a) will be described. The electrolytic plating is not particularly limited, and any electrolytic plating can be applied. However, from the viewpoint of high reliability and good conductivity, electrolytic plated copper is preferably applicable. As the electrolytically plated copper, an acidic copper sulfate plating solution, a copper pyrophosphate plating solution, or the like may be used, and since the management of the solution is easy, it is preferable to use an acidic copper sulfate plating solution.

  Next, the resin material will be described. The resin material used for the flexible printed wiring board of the present invention is not particularly limited, and may be a resin material made only of a polymer film, and an adhesive layer is formed on one or both surfaces of the polymer film. It may be a resin material.

  As the polymer film, a material excellent in low thermal expansion property, heat resistance and mechanical properties is preferable. For example, polyolefin such as polyethylene, polypropylene, polybutene; polyester such as ethylene-vinyl alcohol copolymer, polystyrene, polyethylene terephthalate, polybutylene terephthalate, ethylene-2,6-naphthalate; and nylon-6, nylon-11, aromatic Polyamide polyamide, polyamideimide resin, polycarbonate, polyvinyl chloride, polyvinylidene chloride, polyketone resin, polysulfone resin, polyphenylene sulfide resin, polyetherimide resin, fluororesin, polyarylate resin, liquid crystal polymer resin, polyphenylene ether resin, heat Examples thereof include films of plastic polyimide resin and non-thermoplastic polyimide resin.

  Here, a non-thermoplastic polyimide film is preferably used from the viewpoints of heat resistance, dimensional stability, and the like.

  The polymer film can be subjected to various surface treatments for the purpose of improving adhesiveness. Specifically, a method of applying various organic substances such as a thermosetting resin, a thermoplastic resin, an organic monomer, and a coupling agent as a primer, a method of surface treatment with a metal hydroxide, an organic alkali, etc., a plasma treatment, a corona treatment And a method of surface treatment in the production stage of the polymer film, such as a method of grafting the surface and the like. The polymer film surface may be treated alone or in various combinations.

  Although there is no restriction | limiting in particular in the thickness of a polymer film, When considering thinning of a flexible printed wiring board, Preferably it is 1-70 micrometers, More preferably, it is 1-50 micrometers.

  One role of the adhesive layer is to bond the polymer film and the copper foil when laminating the copper foil. Any adhesive layer may be used provided that this requirement is met.

  Another role of the adhesive layer is to adhere the polymer film and the electroless plating layer when forming the electroless plating. Any adhesive layer may be used as long as this requirement is satisfied, but it is an adhesive layer containing a polyimide resin from the viewpoint of firmly adhering to electroless plating and firmly adhering to a polymer film. It is more preferable that the adhesive layer contains a polyimide resin and an epoxy resin.

  In consideration of adhesiveness with the electroless plating film, among polyimide resins, an adhesive containing a polyimide resin having one or more structures among the structures represented by any one of the general formulas (1) to (6) An agent layer is preferred.

（式中、Ｒ^１およびＲ^３は、それぞれ独立して、Ｃ_ＸＨ_２Ｘで表される２価のアルキレン基、または２価の芳香族基を表す。また、Ｒ^４は、同一でも異なっていてもよく、それぞれ独立して、アルキル基、フェニル基、アルコキシ基、またはフェノキシ基を表し、Ｒ^２は、Ｃ_ＸＨ_２Ｘで表される２価のアルキレン基、または２価のフェニレン基を表す。さらに、ｎ＝３〜１００であり、ｍは１〜２００の整数である。）
以下に、一般式（１）〜（６）のいずれかで表される構造のうち、１つ以上の構造を有するポリイミド樹脂について説明する。

(In the formula, R ¹ and R ³ each independently represents a divalent alkylene group represented by C _X H _2X or a divalent aromatic group. Also, R ⁴ is the same or different. Each independently represents an alkyl group, a phenyl group, an alkoxy group, or a phenoxy group, and R ² represents a divalent alkylene group represented by C _X H _2X or a divalent phenylene group. Furthermore, n = 3 to 100 and m is an integer of 1 to 200.)
Below, the polyimide resin which has one or more structures among the structures represented by either of General formula (1)-(6) is demonstrated.

  Of the structures represented by any one of the above general formulas (1) to (6), the polyimide resin having one or more structures is represented by any one of the above general formulas (1) to (6). Any polyimide resin may be used as long as it has one or more structures. For example, in the structure represented by any one of the general formulas (1) to (6), the acid dianhydride component having one or more structures or the general formulas (1) to (6) Among the structures represented, a diamine component having one or more structures is used to produce a polyamic acid that is a precursor of a polyimide resin, and a method of imidizing this to produce a polyimide resin, an acid having a functional group A polyamic acid having a functional group is produced by using a dianhydride component or a diamine component having a functional group, and the functional group capable of reacting with the functional group and any one of the general formulas (1) to (6). A polyamic acid in which one or more structures are introduced among the structures represented by any one of (1) to (6) is produced by reacting a compound having one or more structures And imidize this to polyimide A method for producing a fat, an acid dianhydride component having a functional group or a diamine component having a functional group is used to produce a polyamic acid having a functional group, and this is imidized to produce a polyimide having a functional group. A compound having one or more structures among the functional group capable of reacting with the functional group and the structure represented by any one of the general formulas (1) to (6) is reacted, and (1) to (6 ), A method for producing a polyimide resin in which one or more structures are introduced, and the like. Here, among the structures represented by any one of the general formulas (1) to (6), a diamine having one or more structures can be obtained relatively easily. A target polyimide resin is produced by reacting an acid dianhydride component with a diamine component having one or more structures among the structures represented by any of the general formulas (1) to (6). It is preferable.

  Next, as the polyimide resin of the present invention, an acid dianhydride component and a diamine component having one or more structures among the structures represented by any of the general formulas (1) to (6) are used. An example of manufacturing in the case of such a case will be described.

  The acid dianhydride component is not particularly limited, and pyromellitic dianhydride, 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride, 3,3 ′, 4,4′-diphenylsulfonetetra Carboxylic dianhydride, 1,4,5,8-naphthalene tetracarboxylic dianhydride, 2,3,6,7-naphthalene tetracarboxylic dianhydride, 4,4′-oxydiphthalic anhydride, 3, 3 ′, 4,4′-dimethyldiphenylsilanetetracarboxylic dianhydride, 1,2,3,4-furantetracarboxylic dianhydride, 4,4′-bis (3,4-dicarboxyphenoxy) diphenyl Propanic acid dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, 2,3,3 ′, 4′-biphenyltetracarboxylic dianhydride, p-phenylenediphthalic anhydride Such Aromatic tetracarboxylic dianhydride, 4,4′-hexafluoroisopropylidenediphthalic anhydride, 4,4′-oxydiphthalic anhydride, 3,4′-oxydiphthalic anhydride, 3,3′-oxydiphthalate Acid anhydride, 4,4 ′-(4,4′-isopropylidenediphenoxy) bis (phthalic anhydride), 4,4′-hydroquinonebis (phthalic anhydride), 2,2-bis (4-hydroxyphenyl) ) Propanedibenzoate-3,3 ′, 4,4′-tetracarboxylic dianhydride, 1,2-ethylenebis (trimellitic acid monoester anhydride), p-phenylenebis (trimellitic acid monoester anhydride) And the like. These may be used alone or in combination of two or more.

  Subsequently, the diamine component will be described. As the diamine component, it is preferable to include a diamine component having one or more structures among the structures represented by the following general formulas (1) to (6).

（式中、Ｒ^１およびＲ^３は、それぞれ独立して、Ｃ_ＸＨ_２Ｘで表される２価のアルキレン基、または２価の芳香族基を表す。また、Ｒ^４は、同一でも異なっていてもよく、それぞれ独立して、アルキル基、フェニル基、アルコキシ基、またはフェノキシ基を表し、Ｒ^２は、Ｃ_ＸＨ_２Ｘで表される２価のアルキレン基、または２価のフェニレン基を表す。さらに、ｎ＝３〜１００であり、ｍは１〜２００の整数である。）
上記一般式（１）で表される構造を有するジアミンとしては、ヘキサメチレンジアミンや、オクタメチレンジアミンなどを例示することができる。上記一般式（２）で表される構造を有するジアミンとしては、１，３−ビス（４−アミノフェノキシ）プロパン、１，４−ビス（４−アミノフェノキシ）ブタン、１，５−ビス（４−アミノフェノキシ）ペンタン等を挙げることができる。上記一般式（３）で表される構造を有するジアミンとしては、エラスマー１０００Ｐ、エラスマー６５０Ｐ、エラスマー２５０Ｐ（イハラケミカル工業（株）製）が挙げられる。また、上記一般式（４）で表される構造を有するジアミンとしては、ポリエーテルポリアミン類、ポリオキシアルキレンポリアミン類を挙げる事ができ、ジェファーミンＤ−２０００、ジェファーミンＤ−４０００（ハンツマン・コーポレーション社製）等を例示することができる。さらに、上記一般式（６）で表される構造を有するジアミンとしては、１,１，３，３，−テトラメチル−１，３−ビス（４−アミノフェニル）ジシロキサン、１,１，３，３，−テトラフェノキシ−１，３−ビス（４−アミノエチル）ジシロキサン、１,１，３，３，５，５−ヘキサメチル−１，５−ビス（４−アミノフェニル）トリシロキサン、１,１，３，３，−テトラフェニル−１，３−ビス（２−アミノフェニル）ジシロキサン、１,１，３，３，−テトラフェニル−１，３−ビス（３−アミノプロピル）ジシロキサン、１,１，５，５，−テトラフェニル−３，３−ジメチル−１，５−ビス（３−アミノプロピル）トリシロキサン、１,１，５，５，−テトラフェニル−３，３−ジメトキシ−１，５−ビス（３−アミノブチル）トリシロキサン、１,１，５，５，−テトラフェニル−３，３−ジメトキシ−１，５−ビス（３−アミノペンチル）トリシロキサン、１,１，３，３，−テトラメチル−１，３−ビス（２−アミノエチル）ジシロキサン、１,１，３，３，−テトラメチル−１，３−ビス（３−アミノプロピル）ジシロキサン、１,１，３，３，−テトラメチル−１，３−ビス（４−アミノブチル）ジシロキサン、１，３−ジメチル−１，３−ジメトキシ−１，３−ビス（４−アミノブチル）ジシロキサン、１,１，５，５，−テトラメチル−３，３−ジメトキシ−１，５−ビス（２−アミノエチル）トリシロキサン、１,１，５，５，−テトラメチル−３，３−ジメトキシ−１，５−ビス（４−アミノブチル）トリシロキサン、１,１，５，５，−テトラメチル−３，３−ジメトキシ−１，５−ビス（５−アミノペンチル）トリシロキサン、１,１，３，３，５，５−ヘキサメチル−１，５−ビス（３−アミノプロピル）トリシロキサン、１,１，３，３，５，５−ヘキサエチル−１，５−ビス（３−アミノプロピル）トリシロキサン、１,１，３，３，５，５−ヘキサプロピル−１，５−ビス（３−アミノプロピル）トリシロキサン、等が挙げられる。また、一般式（６）で表される構造を有する、比較的入手しやすいジアミンとして、信越化学工業株式会社製のＫＦ−８０１０、Ｘ−２２−１６１Ａ、Ｘ−２２−１６１Ｂ、Ｘ−２２−１６６０Ｂ−３、ＫＦ−８００８、ＫＦ−８０１２、Ｘー２２−９３６２、等を挙げることができる。上記一般式（１）〜（６）で表される構造を有するジアミンは単独で用いてもよく、２種以上を混合してもよい。

(In the formula, R ¹ and R ³ each independently represents a divalent alkylene group represented by C _X H _2X or a divalent aromatic group. Also, R ⁴ is the same or different. Each independently represents an alkyl group, a phenyl group, an alkoxy group, or a phenoxy group, and R ² represents a divalent alkylene group represented by C _X H _2X or a divalent phenylene group. Furthermore, n = 3 to 100 and m is an integer of 1 to 200.)
Examples of the diamine having the structure represented by the general formula (1) include hexamethylene diamine and octamethylene diamine. Examples of the diamine having the structure represented by the general formula (2) include 1,3-bis (4-aminophenoxy) propane, 1,4-bis (4-aminophenoxy) butane, and 1,5-bis (4 -Aminophenoxy) pentane and the like. Examples of the diamine having the structure represented by the general formula (3) include Elastomer 1000P, Elastomer 650P, and Elastomer 250P (manufactured by Ihara Chemical Industry Co., Ltd.). Further, examples of the diamine having the structure represented by the general formula (4) include polyether polyamines and polyoxyalkylene polyamines, such as Jeffamine D-2000 and Jeffamine D-4000 (Huntsman Corporation). Etc.). Furthermore, as the diamine having the structure represented by the general formula (6), 1,1,3,3-tetramethyl-1,3-bis (4-aminophenyl) disiloxane, 1,1,3 , 3, -tetraphenoxy-1,3-bis (4-aminoethyl) disiloxane, 1,1,3,3,5,5-hexamethyl-1,5-bis (4-aminophenyl) trisiloxane, 1,1,3,3-Tetraphenyl-1,3-bis (2-aminophenyl) disiloxane, 1,1,3,3, -tetraphenyl-1,3-bis (3-aminopropyl) disiloxane 1,1,5,5, -tetraphenyl-3,3-dimethyl-1,5-bis (3-aminopropyl) trisiloxane, 1,1,5,5, -tetraphenyl-3,3-dimethoxy -1,5-bis (3-aminobutyl) trisiloxy Sun 1,1,5,5, -tetraphenyl-3,3-dimethoxy-1,5-bis (3-aminopentyl) trisiloxane, 1,1,3,3, -tetramethyl-1,3- Bis (2-aminoethyl) disiloxane, 1,1,3,3-tetramethyl-1,3-bis (3-aminopropyl) disiloxane, 1,1,3,3, -tetramethyl-1, 3-bis (4-aminobutyl) disiloxane, 1,3-dimethyl-1,3-dimethoxy-1,3-bis (4-aminobutyl) disiloxane, 1,1,5,5, -tetramethyl- 3,3-dimethoxy-1,5-bis (2-aminoethyl) trisiloxane, 1,1,5,5-tetramethyl-3,3-dimethoxy-1,5-bis (4-aminobutyl) trisiloxane Siloxane, 1,1,5,5-tetramethyl-3,3-dimeth Xyl-1,5-bis (5-aminopentyl) trisiloxane, 1,1,3,3,5,5-hexamethyl-1,5-bis (3-aminopropyl) trisiloxane, 1,1,3 3,5,5-hexaethyl-1,5-bis (3-aminopropyl) trisiloxane, 1,1,3,3,5,5-hexapropyl-1,5-bis (3-aminopropyl) trisiloxane , Etc. Further, as relatively easily available diamines having a structure represented by the general formula (6), KF-8010, X-22-161A, X-22-161B, X-22-manufactured by Shin-Etsu Chemical Co., Ltd. 1660B-3, KF-8008, KF-8012, X-22-9362, and the like. The diamine having the structure represented by the general formulas (1) to (6) may be used alone or in combination of two or more.

  For the purpose of improving heat resistance and the like, it is also preferable to use a diamine having one or more structures among the structures represented by the general formulas (1) to (6) in combination with another diamine. As the other diamine component, any diamine can be used, and m-phenylenediamine, o-phenylenediamine, p-phenylenediamine, m-aminobenzylamine, p-aminobenzylamine, bis (3-amino). Phenyl) sulfide, (3-aminophenyl) (4-aminophenyl) sulfide, bis (4-aminophenyl) sulfide, bis (3-aminophenyl) sulfoxide, (3-aminophenyl) (4-aminophenyl) sulfoxide, Bis (3-aminophenyl) sulfone, (3-aminophenyl) (4-aminophenyl) sulfone, bis (4-aminophenyl) sulfone, 3,4'-diaminobenzophenone, 4,4'-diaminobenzophenone, 3, 3'-diaminodiphenylmethane, 3,4'-di Minodiphenylmethane, 4,4′-diaminodiphenylmethane, 4,4′-diaminodiphenyl ether, 3,3′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, bis [4- (3-aminophenoxy) phenyl] sulfoxide, bis [4- (Aminophenoxy) phenyl] sulfoxide, 4,4′-diaminodiphenyl ether, 3,4′-diaminodiphenyl ether, 3,3′-diaminodiphenyl ether, 4,4′-diaminodiphenylthioether, 3,4′-diamino Diphenylthioether, 3,3'-diaminodiphenylthioether, 3,3'-diaminodiphenylmethane, 3,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfur 3,4'-diaminodiphenylsulfone, 3,3'-diaminodiphenylsulfone, 4,4'-diaminobenzanilide, 3,4'-diaminobenzanilide, 3,3'-diaminobenzanilide, 4, 4'-diaminobenzophenone, 3,4'-diaminobenzophenone, 3,3'-diaminobenzophenone, bis [4- (3-aminophenoxy) phenyl] methane, bis [4- (4-aminophenoxy) phenyl] methane 1,1-bis [4- (3-aminophenoxy) phenyl] ethane, 1,1-bis [4- (4-aminophenoxy) phenyl] ethane, 1,2-bis [4- (3-aminophenoxy) ) Phenyl] ethane, 1,2-bis [4- (4-aminophenoxy) phenyl] ethane, 2,2-bis [4- (3-aminophenyl) Enoxy) phenyl] propane, 2,2-bis [4- (4-aminophenoxy) phenyl] propane, 2,2-bis [4- (3-aminophenoxy) phenyl] butane, 2,2-bis [3- (3-Aminophenoxy) phenyl] -1,1,1,3,3,3-hexafluoropropane, 2,2-bis [4- (4-aminophenoxy) phenyl] -1,1,1,3 3,3-hexafluoropropane, 1,3-bis (3-aminophenoxy) benzene, 1,4-bis (3-aminophenoxy) benzene, 1,4′-bis (4-aminophenoxy) benzene, 4, 4′-bis (4-aminophenoxy) biphenyl, bis [4- (3-aminophenoxy) phenyl] ketone, bis [4- (4-aminophenoxy) phenyl] ketone, bis [4- (3- Minophenoxy) phenyl] sulfide, bis [4- (4-aminophenoxy) phenyl] sulfide, bis [4- (3-aminophenoxy) phenyl] sulfone, bis [4- (4-aminophenoxy) phenyl] sulfone, bis [4- (3-aminophenoxy) phenyl] ether, bis [4- (4-aminophenoxy) phenyl] ether, 1,4-bis [4- (3-aminophenoxy) benzoyl] benzene, 1,3-bis [4- (3-aminophenoxy) benzoyl] benzene, 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] ben Phenone, 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) -α, α-dimethylbenzyl] benzene, 1,3-bis [4- (4-aminophenoxy) -α, α-dimethylbenzyl] benzene, 3,3′- Examples thereof include dihydroxy-4,4′-diaminobiphenyl.

  Here, from the viewpoint of easy availability of raw materials and adhesion with the electroless plating film, among the diamines having one or more structures among the structures represented by the general formulas (1) to (6), the following It is preferable that the diamine which has a structure represented by General formula (6) is contained.

（式中、Ｒ^１およびＲ^３は、それぞれ独立して、Ｃ_ＸＨ_２Ｘで表される２価のアルキレン基、または２価の芳香族基を表す。また、Ｒ^４は、同一でも異なっていてもよく、それぞれ独立して、アルキル基、フェニル基、アルコキシ基、またはフェノキシ基を表す。さらに、ｍは１〜２００の整数である。）
上記一般式（１）〜（６）で表される構造のうち、１つ以上の構造を有するジアミンは、全ジアミン成分に対して２〜１００モル％が好ましく、より好ましくは５〜１００モル％である。上記一般式（１）〜（６）で表される構造のうち、１つ以上の構造を有するジアミンが、全ジアミン成分に対して２モル％より少ない場合、表面ａと無電解めっき皮膜との接着強度が低くなる場合がある。

(In the formula, R ¹ and R ³ each independently represents a divalent alkylene group represented by C _X H _2X or a divalent aromatic group. Also, R ⁴ is the same or different. And each independently represents an alkyl group, a phenyl group, an alkoxy group, or a phenoxy group, and m is an integer of 1 to 200.)
Among the structures represented by the general formulas (1) to (6), the diamine having one or more structures is preferably 2 to 100 mol%, more preferably 5 to 100 mol%, based on the total diamine component. It is. When the diamine having one or more structures among the structures represented by the general formulas (1) to (6) is less than 2 mol% with respect to the total diamine component, the surface a and the electroless plating film Adhesive strength may be lowered.

  The polyimide is obtained by dehydrating and ring-closing the corresponding precursor polyamic acid. The polyamic acid is obtained by reacting an acid dianhydride component and a diamine component in substantially equimolar amounts.

  A typical procedure for the reaction is a method in which one or more diamine components are dissolved or dispersed in an organic polar solvent, and then one or more acid dianhydride components are added to obtain a polyamic acid solution. The order of addition of each monomer is not particularly limited, and the acid dianhydride component may be added to the organic polar solvent in advance, and the diamine component may be added to form a polyamic acid polymer solution, or the diamine component may be added to the organic polar solvent. A suitable amount of the acid dianhydride component may be added first, and then an excess amount of the dianhydride component may be added, and a diamine component corresponding to the excess amount may be added to form a polyamic acid polymer solution. There are various other addition methods known to those skilled in the art. Specifically, the following method is mentioned.

As used herein, “dissolution” refers to the case where the solute is uniformly dispersed in the solvent and substantially dissolved in addition to the case where the solvent completely dissolves the solute. Including. The reaction time and reaction temperature are not particularly limited.
1) A method in which a diamine component is dissolved in an organic polar solvent, and this is reacted with a substantially equimolar acid dianhydride component for polymerization.
2) An acid dianhydride component and a small molar amount of the diamine component are reacted with each other in an organic polar solvent to obtain a prepolymer having acid anhydride groups at both ends. Then, the method of superposing | polymerizing using a diamine component so that an acid dianhydride component and a diamine component may become substantially equimolar in all the processes.
3) The acid dianhydride component is reacted with an excess molar amount of the diamine component in an organic polar solvent to obtain a prepolymer having amino groups at both ends. Subsequently, after the addition of the diamine component, the polymerization is performed using the acid dianhydride component so that the acid dianhydride component and the diamine component are substantially equimolar in all steps.
4) A method in which an acid dianhydride component is dissolved in an organic polar solvent and then polymerized using a diamine compound component so as to be substantially equimolar.
5) A method of polymerizing by reacting a substantially equimolar mixture of an acid dianhydride component and a diamine component in an organic polar solvent.

  Examples of the organic polar solvent used for the polyamic acid polymerization reaction include sulfoxide solvents such as dimethyl sulfoxide and diethyl sulfoxide, formamide solvents such as N, N-dimethylformamide and N, N-diethylformamide, N, N- Acetamide solvents such as dimethylacetamide and N, N-diethylacetamide, pyrrolidone solvents such as N-methyl-2-pyrrolidone and N-vinyl-2-pyrrolidone, phenol, o-, m- or p-cresol, xylenol, Examples thereof include phenol solvents such as halogenated phenols and catechols, hexamethylphosphoramide, and γ-butyrolactone. Further, if necessary, these organic polar solvents can be used in combination with an aromatic hydrocarbon such as xylene or toluene.

  The polyamic acid solution obtained by the above method is dehydrated and cyclized by a thermal or chemical method to obtain a polyimide, and a thermal method in which the polyamic acid solution is subjected to heat treatment for dehydration, a chemical method for dehydration using a dehydrating agent. Any of these can be used. Moreover, the method of imidating by heating under reduced pressure can also be used. Each method will be described below.

  As a method of thermally dehydrating and cyclizing, a method of evaporating the solvent at the same time that the polyamic acid solution is subjected to an imidation reaction by heat treatment can be exemplified. By this method, a solid polyimide resin can be obtained. The heating conditions are not particularly limited, but it is preferably performed at a temperature of 200 ° C. or lower for a time range of 1 second to 200 minutes.

  Further, as a method of chemically dehydrating and cyclizing, a method of causing a dehydration reaction by adding a dehydrating agent and a catalyst having a stoichiometric amount or more to the polyamic acid solution and evaporating the organic solvent can be exemplified. Thereby, a solid polyimide resin can be obtained. Examples of the dehydrating agent include aliphatic acid anhydrides such as acetic anhydride and aromatic acid anhydrides such as benzoic anhydride. Examples of the catalyst include aliphatic tertiary amines such as triethylamine, aromatic tertiary amines such as dimethylaniline, and heterocyclic rings such as pyridine, α-picoline, β-picoline, γ-picoline, and isoquinoline. And tertiary amines of the formula. The conditions for chemically dehydrating and cyclizing are preferably 100 ° C. or less, and the organic solvent is preferably evaporated at a temperature of 200 ° C. or less for a period of about 5 minutes to 120 minutes.

  Further, as another method for obtaining a polyimide resin, there is a method in which the solvent is not evaporated in the thermal or chemical dehydration ring closure method. Specifically, a polyimide solution obtained by performing a thermal imidization treatment or a chemical imidization treatment with a dehydrating agent is put into a poor solvent, a polyimide resin is precipitated, and unreacted monomers are removed and purified and dried. And obtaining a solid polyimide resin. As the poor solvent, a solvent that is well mixed with the solvent but is difficult to dissolve polyimide is selected. Illustrative examples include, but are not limited to, acetone, methanol, ethanol, isopropanol, benzene, methyl cellosolve, methyl ethyl ketone, and the like.

  Next, although it is the method of imidating by heating under reduced pressure, according to this imidization method, water generated by imidization can be actively removed out of the system, so that hydrolysis of polyamic acid is suppressed. And a high molecular weight polyimide is obtained. In addition, according to this method, one-sided or both-side ring-opened products existing as impurities in the raw acid dianhydride are closed again, so that a further improvement in molecular weight can be expected.

  The heating condition of the method of heating imidization under reduced pressure is preferably 80 to 400 ° C., more preferably 100 ° C. or more, more preferably 120 ° C. or more, in which imidization is efficiently performed and water is efficiently removed. is there. The maximum temperature is preferably equal to or lower than the thermal decomposition temperature of the target polyimide, and a normal imidization completion temperature, that is, about 150 to 350 ° C. is usually applied.

The conditions for pressure reduction are preferably smaller, but specifically, 9 × 10 ⁴ to 1 × 10 ² Pa, preferably 8 × 10 ⁴ to 1 × 10 ² Pa, more preferably 7 × 10 ⁴ to 1. × 10 ² Pa.

  Although the polyimide resin has been described above, a polyimide resin having one or more structures among the structures represented by any one of the above-described general formulas (1) to (6) may be used. As an example of the polyimide resin containing the said general formula (6) which can be used for the electroless-plating material of this invention and is comparatively easily available, X-22-8917, X-22- by Shin-Etsu Chemical Co., Ltd. 8904, X-22-8951, X-22-8756, X-22-8984, X-22-8985, and the like. These are polyimide solutions.

  Although there is no restriction | limiting in particular in the thickness of an adhesive bond layer, When thinning of a flexible printed wiring board is considered, Preferably it is 0.01-20 micrometers, More preferably, it is 0.01-10 micrometers.

<Thickness of conductor layer at opening of through hole (b)>
From the viewpoint of ensuring the reliability of the through-hole and from the viewpoint of satisfactorily forming fine wiring, the conductor layer thickness (b) of the through-hole opening is preferably 3 μm or more and 20 μm or less.
The conductor layer thickness (b) of the through-hole opening does not depend on the form of the material used for manufacturing the flexible printed wiring board of the present invention. Because when using a laminate composed of copper foil / resin material / copper foil, when using a laminate composed of dry plating / resin material / dry plating,
Also, in the case of using a material consisting only of a resin material, after through-hole processing, since the resin material is exposed in the through-hole opening, some kind of base metal layer is formed in the through-hole opening. There is a need. The method for forming the base metal layer is not particularly limited, but it is preferable to perform the electroless plating from advantages such as ease of processing and uniformity of processing. In addition, since a method of forming a conductor layer with a certain thickness by electroless plating is inferior in productivity, after forming a conductor layer of about 1 μm or less by electroless plating, electrolytic plating is performed so that a desired thickness is obtained. The method used is preferably used. The electroless plating and electrolytic plating may be performed by the same method as described in the explanation of the thickness (a) of the wiring formed on the surface.

<(A)-(b)>
In the flexible printed wiring board according to the present invention, the relationship (a) − (b) ≦ 10 μm between the thickness (a) of the wiring formed on the surface and the conductor layer thickness (b) of the through hole opening. Is established. Further, it is more preferable that the relationship (a) − (b) ≦ 5 μm is satisfied, and it is particularly preferable that the relationship (a) − (b) ≦ 0 is satisfied.

  When (a)-(b) is larger than 10 μm, the case where the thickness of (a) is thick and the case where the thickness of (b) is thin can be considered. When the thickness of (b) is thin, there is a problem that the reliability of the through hole cannot be obtained.

<Wiring width (c) and wiring interval (d)>
First, the wiring width (c) will be described. In the flexible printed wiring board of the present invention, the wiring width (c) preferably includes 20 μm or less, and includes 15 μm or less from the viewpoint of obtaining a high-density flexible printed wiring board. More preferably. Of course, there is no problem even if the flexible printed wiring board of the present invention includes a wiring width (c) of 20 μm or more.

  Next, the wiring interval (d) of the present invention will be described. In relation to the wiring width (c), the wiring interval (d) preferably satisfies (d) / (c) ≦ 2.0, and further satisfies (d) / (c) ≦ 1.5. preferable. When (d) / (c) is larger than 2.0, wiring formation becomes easy, but extra space is required as the wiring interval (d) increases, so a high-density flexible printed wiring board is required. It will deviate from the purpose of obtaining.

  Therefore, the wiring interval (d) preferably includes 40 μm or less, and more preferably 30 μm or less.

  More preferably, the wiring width (c) and the wiring interval (d) of the wiring formed on the surface are each 20 μm or less.

  Of course, the flexible printed wiring board of the present invention may have a wiring interval (d) of 40 μm or more.

<(A) / (c)>
In the flexible printed wiring board of the present invention, a relationship of (a) / (c) ≦ 2.0 may be established between the thickness (a) of the wiring formed on the surface and the wiring width (c). It is more preferable that the relationship (a) / (c) ≦ 1.5 is satisfied. When (a) / (c) is larger than 2.0, when the wiring is formed by the semi-additive method, the wiring is easily peeled off. When the wiring is formed by the subtractive method, the wiring shape is formed by side etching. This causes problems such as abnormalities in etching, and the possibility of residual etching.

<Flexible printed wiring board>
The flexible printed wiring board of the present invention is characterized in that fine wiring is satisfactorily formed and through hole reliability is high.

  Also, from the viewpoint of increasing the density of wiring, the flexible printed wiring board of the present invention has a wiring pattern with wiring width (c) and wiring spacing (d) of 20 μm or less and 20 μm or less on the surface, respectively. It is preferable. At this time, the thickness (a) of the wiring formed on the surface is preferably 30 μm or less, and the conductor layer thickness (b) of the through-hole opening is preferably 20 μm or less.

  In this case, (a) − (b) ≦ 10 is satisfied, (a) / (c) ≦ 2.0 is satisfied, and (d) / (c) ≦ 2.0 is satisfied. A flexible printed wiring board that achieves both formability and through hole reliability can be obtained.

<Method for producing flexible printed wiring board>
A method for producing the flexible printed wiring board of the present invention will be described.
As one of the methods for producing the flexible printed wiring board of the present invention, a step of forming a through hole in an insulating material, a step of forming a base metal layer, a step of performing electrolytic plating, a step of forming a resist pattern, and etching are performed. The method of manufacturing by the process including the process and the process of peeling a resist can be mentioned. This is a wiring formation method called a subtractive construction method. Each step will be described below.

A process of forming a through hole will be described. The through hole can be formed by a known method such as a laser, a mechanical drill, or punching.
A process of forming the base metal layer will be described. The method for forming the base metal layer is not particularly limited, but is preferably performed by electroless plating because of advantages such as ease of processing and uniformity of processing.

  The process of applying electrolytic plating will be described. Any known method can be applied to the electrolytic plating. Here, from the viewpoint of high reliability and good electrical conductivity, electrolytic copper plating is preferably applicable.

  A process for forming a resist pattern will be described. The resist used in the subtractive method is an etching resist. The properties required in this case are adhesion to the surface metal layer and physical strength that does not damage the transfer conveyor roller of the etching apparatus, and any resist can be used as long as this is satisfied. It doesn't matter.

  As a method for forming a resist pattern, a dry film resist or a liquid resist is laminated on the entire surface of the electrolytic copper plating of the present invention, or formed on the entire surface by a method such as coating or drying, and then the resist pattern is formed by exposure and development. Can be formed.

  The process of performing etching will be described. The etching is performed to remove the metal layer portion on the surface where the resist pattern is not formed. The etching solution and conditions are not particularly limited, and may be performed under conditions that can obtain a desired wiring width and wiring shape. When the metal layer portion is made of copper, the etching solution includes nitric acid / hydrogen peroxide etching solution, cupric chloride / hydrochloric acid etching solution, ferric chloride / hydrochloric acid etching solution, persulfate / sulfuric acid etching solution, etc. Can be mentioned.

  The process of peeling the resist will be described. Resist stripping may be performed with appropriate chemicals and conditions according to the type of resist used. In general, an alkaline aqueous solution such as an aqueous sodium hydroxide solution can be applied.

  As another method for producing the flexible printed wiring board of the present invention, a step of forming a through hole in an insulating material, a step of forming a base metal layer, a step of forming a resist pattern, a step of applying electrolytic plating, and stripping the resist The method of manufacturing by the process including the process and the process of performing a flash etching can be mentioned. This is a wiring formation method called a semi-additive construction method. Each step will be described below.

  A process of forming a through hole will be described. As in the case of the subtractive method, it can be formed by a known method.

  A process of forming the base metal layer will be described. The method for forming the base metal layer is not particularly limited, but is preferably performed by electroless plating because of advantages such as ease of processing and uniformity of processing.

A process for forming a resist pattern will be described. The resist used in the semi-additive method is a plating resist. The characteristics required in this case include adhesion to the surface base metal layer, resistance to electrolytic plating solution, and electrolytic plating grows along the side walls of the resist. A standing resist sidewall is required. Any resist may be used as long as this is satisfied.
As a method for forming a resist pattern, a dry film resist or a liquid resist is laminated on the entire surface of the electrolytic copper plating of the present invention, or formed on the entire surface by a method such as coating or drying, and then the resist pattern is formed by exposure and development. Can be formed.

  The process of applying electrolytic plating will be described. Any known method can be applied to the electrolytic plating. Here, from the viewpoint of high reliability and good electrical conductivity, electrolytic copper plating is preferably applicable.

  The process of peeling the resist will be described. Resist stripping may be performed with appropriate chemicals and conditions according to the type of resist used. In general, an alkaline aqueous solution such as an aqueous sodium hydroxide solution can be applied.

  A process for performing flash etching will be described. The flash etching is performed in order to remove the base metal layer portion on the surface where the resist pattern is not formed. The etching solution and conditions are not particularly limited, and may be performed under conditions that can obtain a desired wiring width and wiring shape. When the base metal layer is made of electroless plated copper, the etching solution is nitric acid / hydrogen peroxide etching solution, cupric chloride / hydrochloric acid etching solution, ferric chloride / hydrochloric acid etching solution, persulfate / sulfuric acid etching. Although the electroless plated copper is usually as thin as about 1 μm or less, a persulfate / sulfuric acid etching solution is preferably applicable. Further, when a palladium catalyst is used when forming the electroless plated copper, it is preferable to apply a treatment with a palladium remover for the purpose of improving the insulation reliability between the wirings.

  The flexible printed wiring board and the manufacturing example thereof according to the present invention have been described above. However, the present invention is not limited to this, and those skilled in the art will make various changes, modifications, and alterations without departing from the scope of the present invention. be able to.

  The present invention will be described more specifically based on examples, but the present invention is not limited to this. Those skilled in the art can make various changes, modifications, and alterations without departing from the scope of the present invention. As the characteristics of the flexible printed wiring board of the present invention, the fine wiring formability and the through hole reliability were evaluated or calculated as follows.

[Fine wiring formability evaluation 1]
Through holes were formed in the resin material with a carbon dioxide laser. Thereafter, the exposed resin material surface and the through-hole surface were subjected to desmearing and electroless copper plating by the processes shown in Tables 1 and 2 to form a base metal layer, and subjected to a drying treatment at 150 ° C. for 30 minutes. . Thereafter, electrolytic copper plating is performed to form an etching resist pattern, and then etching is performed with hydrochloric acid / ferric chloride etching solution, and the resist is stripped to form fine wiring of line and space = 20 μm / 20 μm. did. In addition, electroless copper plating thickness and electrolytic copper plating thickness were implemented as shown in Tables 3 and 4.

  The case where the fine wiring was not peeled off and was successfully formed as designed was rated as “◯”, and the case where the fine wiring was peeled off or was not able to be satisfactorily formed as designed was marked as “X”.

〔微細配線形成性評価２〕
樹脂材料に炭酸ガスレーザーにてスルーホールを形成した。その後、露出する樹脂材料表面及びスルーホール表面に、表１、表２に示すプロセスにてデスミア、無電解銅めっきを施して下地金属層を形成し、１５０℃、３０分の乾燥処理を行った。めっきレジストパターン形成、電解銅パターンめっき、レジスト剥離、過硫酸ナトリウム／硫酸エッチング液にてクィックエッチング、の各工程にて処理してラインアンドスペース＝１０μｍ／１０μｍの微細配線を形成した。尚、無電解銅めっき厚み、電解銅めっき厚みは表３、４に記載の通りに実施した。

[Fine wiring formability evaluation 2]
Through holes were formed in the resin material with a carbon dioxide laser. Thereafter, the exposed resin material surface and the through-hole surface were subjected to desmearing and electroless copper plating by the processes shown in Tables 1 and 2 to form a base metal layer, and subjected to a drying treatment at 150 ° C. for 30 minutes. . A fine wiring of line and space = 10 μm / 10 μm was formed by processing in each step of plating resist pattern formation, electrolytic copper pattern plating, resist peeling, and quick etching with sodium persulfate / sulfuric acid etching solution. In addition, electroless copper plating thickness and electrolytic copper plating thickness were implemented as shown in Tables 3 and 4.

  The case where the fine wiring was not peeled off and was successfully formed as designed was rated as “◯”, and the case where the fine wiring was peeled off or was not able to be satisfactorily formed as designed was marked as “X”.

[Through hole reliability]
Through holes were formed in the resin material with a carbon dioxide laser. Thereafter, the exposed resin material surface and the through-hole surface were subjected to desmearing and electroless copper plating by the processes shown in Tables 1 and 2 to form a base metal layer, and subjected to a drying treatment at 150 ° C. for 30 minutes. . Furthermore, electrolytic copper pattern plating was formed. The electroless copper plating was 0.7 μm thick, and the electrolytic copper plating was 8 μm thick. The through holes were formed in an array of 5 × 4 rows so that the through hole diameter was 300 μm, the distance between barrels was 200 μm, and the through hole pitch was 500 μm. Using this sample, a migration test was performed under the conditions of 85 ° C./85%/applied voltage 60V / measured voltage 60V. After conducting the test for 1000 hours, the case where the insulation resistance value was maintained at 100 MΩ or more was rated as “◯”, the case where the insulation resistance value was short-circuited during the test, or the case where the insulation resistance value was below 100 MΩ.

[Example 1]
(Synthesis of polymer film)
2,2-bis [4- (4-aminophenoxy) phenyl] propane (BAPP) / 4,4′-diaminodiphenyl ether (4,4′-ODA) / paraphenylenediamine (p-PDA) / 3,3 ′ , 4,4'-biphenyltetracarboxylic dianhydride (BPDA) / pyromellitic dianhydride (PMDA) in a molar ratio of 25/25/50/30/70, N, N- A dimethylformamide (DMF) solution (solid content concentration 18% by weight) was obtained.

  To 100 g of the above polyamic acid solution, 19 g of acetic anhydride and 7 g of isoquinoline were added and stirred uniformly, then defoamed, cast on a glass plate, dried at about 110 ° C. for about 5 minutes, and then polyamic acid. The coating film was peeled off from the glass plate to obtain a gel film having self-supporting properties. The gel film is fixed to a frame, then heated at about 200 ° C. for about 1 minute, about 300 ° C. for about 1 minute, about 400 ° C. for about 1 minute, about 500 ° C. for about 1 minute, dehydrated and ring-closed and dried, A non-thermoplastic polyimide film (X) having a thickness of 25 μm was obtained.

(Formation of adhesive layer)
In a glass flask with a volume of 2000 ml, 37 g (0.045 mol) of KF-8010 manufactured by Shin-Etsu Chemical Co., Ltd., 21 g (0.105 mol) of 4,4′-diaminodiphenyl ether, N, N-dimethylformamide (hereinafter, DMF) was added and dissolved while stirring, and 78 g (0.15 mol) of 4,4 ′-(4,4′-isopropylidenediphenoxy) bis (phthalic anhydride) was added. The mixture was stirred for a time to obtain a DMF solution of polyamic acid having a solid concentration of 30%. The polyamic acid solution was placed on a fluorine-coated vat and heated under reduced pressure at 665 Pa at 200 ° C. for 120 minutes in a vacuum oven to obtain a polyimide resin (Y). 9 g of polyimide resin (Y), 0.7 g of epoxy resin (NC-3000-H, manufactured by Nippon Kayaku Co., Ltd.), 0.3 g of naphthol / cresol resin (NC-30, manufactured by Gunei Chemical Industry Co., Ltd.), dioxolane 190 g of a mixed solvent of toluene and toluene (mixing ratio = 50 wt% / 50 wt%) was mixed and dissolved to obtain an adhesive solution (Z).

(Production of resin material)
The adhesive solution (Z) was cast on one side of the polymer film (X). Thereafter, it was dried in a hot air oven at a temperature of 150 ° C. for 2 minutes to obtain a resin material composed of a 2 μm thick adhesive layer / 25 μm thick polymer film. The adhesive solution (Z) is cast on the surface opposite to the surface on which the adhesive layer of the resin material is formed, then dried in a hot air oven at a temperature of 150 ° C. for 2 minutes, and further 180 ° C. And dried at a temperature of 30 minutes to obtain a resin material (A) comprising an adhesive layer having a thickness of 2 μm / a polymer film having a thickness of 25 μm / an adhesive layer having a thickness of 2 μm.

(Evaluation)
Using the resin material, the evaluation was performed as described in the fine wiring formability evaluation 1 and the through-hole reliability evaluation. Table 3 shows the thickness (a) of the wiring formed on the surface and the conductor layer thickness (b) of the through-hole opening. The evaluation results are shown in Table 3.

[Example 2]
Using the same resin material used in Example 1, the evaluation was performed as described in the fine wiring formability evaluation 2 and the through-hole reliability evaluation. Table 3 shows the thickness (a) of the wiring formed on the surface and the conductor layer thickness (b) of the through-hole opening. The evaluation results are shown in Table 3.

Example 3
A laminate (underlying metal: NiCr: 0.1 μm, copper: 0.9 μm) composed of an underlying metal layer / resin material / underlying metal layer obtained by sputtering and plating on a polymer film (X) by a conventional method. The same evaluation as in Example 1 was performed. Table 3 shows the thickness (a) of the wiring formed on the surface and the conductor layer thickness (b) of the through-hole opening. The evaluation results are shown in Table 3.

Example 4
Evaluation was carried out in the same manner as in Example 2 using the same base metal layer / resin material / base metal layer laminate as used in Example 3. Table 3 shows the thickness (a) of the wiring formed on the surface and the conductor layer thickness (b) of the through-hole opening. The evaluation results are shown in Table 3.

Example 5
Resin material (A ′) comprising an adhesive layer having a thickness of 2 μm / polymer film having a thickness of 25 μm / adhesive layer having a thickness of 2 μm, in the same manner as in Example 1 except that it was not dried at 180 ° C. for 30 minutes. Got. 9 μm-thick rolled copper foil is laminated so that the mat surface is in contact with the adhesive layer, and press-bonded under conditions of 180 ° C., 3 MPa, 1 hour, 9 μm-thick rolled copper foil / thickness-adhesive layer / thickness 2 μm A laminate comprising a 25 μm polymer film / a 2 μm thick adhesive layer / a 9 μm thick rolled copper foil was obtained. Evaluation similar to Example 1 was performed using this laminated body. Table 3 shows the thickness (a) of the wiring formed on the surface and the conductor layer thickness (b) of the through-hole opening. The evaluation results are shown in Table 3.

Example 6
Except for using 5 μm-thick rolled copper foil, in the same manner as in Example 5, 5 μm-thick rolled copper foil / thickness 2 μm adhesive layer / 25 μm thick polymer film / thickness 2 μm adhesive layer / thickness 5 μm A laminate made of rolled copper foil was obtained. Evaluation similar to Example 2 was performed using this laminated body. Table 3 shows the thickness (a) of the wiring formed on the surface and the conductor layer thickness (b) of the through-hole opening. The evaluation results are shown in Table 3.

[Comparative Example 1]
0.7 g of epoxy resin (NC-3000-H, manufactured by Nippon Kayaku Co., Ltd.), 0.3 g of naphthol / cresol resin (NC-30, manufactured by Gunei Chemical Industry Co., Ltd.), mixed solvent of dioxolane and toluene (mixing ratio) = 50 wt% / 50 wt%) was mixed and dissolved in 190 g to obtain an adhesive solution (P). The adhesive solution (P) was cast on one side of the polymer film (X). Thereafter, it was dried in a hot air oven at a temperature of 150 ° C. for 2 minutes to obtain a resin material comprising an adhesive layer having a thickness of 1 μm / a polymer film having a thickness of 25 μm. The adhesive solution (Z) is cast on the surface opposite to the surface on which the adhesive layer of the resin material is formed, and then dried in a hot air oven at a temperature of 150 ° C. for 2 minutes. A resin material (B) comprising an adhesive layer / a polymer film having a thickness of 25 μm / an adhesive layer having a thickness of 1 μm was obtained. Stacked so that the mat surface of the rolled copper foil having a thickness of 35 μm and the adhesive layer are in contact with each other, and press-bonded under conditions of 180 ° C., 3 MPa, and 1 hour, rolled copper foil having a thickness of 35 μm / adhesive layer having a thickness of 1 μm / thickness. A laminate composed of 25 μm polymer film / adhesive layer having a thickness of 1 μm / rolled copper foil having a thickness of 35 μm was obtained. Evaluation similar to Example 1 was performed using this laminated body. Table 4 shows the thickness (a) of the wiring formed on the surface and the conductor layer thickness (b) of the through-hole opening. The evaluation results are shown in Table 4.

[Comparative Example 2]
Except for using 18 μm rolled copper foil, in the same manner as in Comparative Example 1, 18 μm thick rolled copper foil / 1 μm thick adhesive layer / 25 μm thick polymer film / 1 μm thick adhesive layer / 18 μm thick rolled A laminate made of copper foil was obtained. Evaluation similar to Example 1 was performed using this laminated body. Table 4 shows the thickness (a) of the wiring formed on the surface and the conductor layer thickness (b) of the through-hole opening. The evaluation results are shown in Table 4.

[Comparative Example 3]
Using the same laminate as Comparative Example 2, the same evaluation as in Example 1 was performed. Table 4 shows the thickness (a) of the wiring formed on the surface and the conductor layer thickness (b) of the through-hole opening. The evaluation results are shown in Table 4.

[Comparative Example 4]
Using the same laminate as Comparative Example 2, the same evaluation as in Example 2 was performed. Table 4 shows the thickness (a) of the wiring formed on the surface and the conductor layer thickness (b) of the through-hole opening. The evaluation results are shown in Table 4.

[Comparative Example 5]
Using the same laminate as Comparative Example 2, the same evaluation as in Example 2 was performed. Table 4 shows the thickness (a) of the wiring formed on the surface and the conductor layer thickness (b) of the through-hole opening. The evaluation results are shown in Table 4.

なお本発明は、以上説示した各構成に限定されるものではなく、特許請求の範囲に示した範囲で種々の変更が可能であり、異なる実施形態や実施例にそれぞれ開示された技術的手段を適宜組み合わせて得られる実施形態についても本発明の技術的範囲に含まれる。

Note that the present invention is not limited to the configurations described above, and various modifications are possible within the scope of the claims, and technical means disclosed in different embodiments and examples respectively. Embodiments obtained by appropriate combinations are also included in the technical scope of the present invention.

  The flexible printed wiring board of the present invention is useful as a flexible printed wiring board capable of high-density mounting because both the reliability of through holes and the fine wiring formability are compatible. Therefore, the present invention can be suitably used in the industrial field of various electronic components.

Claims (10)

  A flexible printed wiring characterized in that a relationship of (a) − (b) ≦ 10 μm is established between the thickness (a) of the wiring formed on the surface and the conductor layer thickness (b) of the through-hole opening. Board.   The flexible printed wiring board according to claim 1, wherein a relationship of (a) − (b) ≦ 5 μm is established. The flexible printed wiring board according to claim 1, wherein a relationship of (a) − (b) ≦ 0 is established.   The relationship of (a) / (c) ≦ 2.0 is established between the thickness (a) of the wiring formed on the surface and the wiring width (c). The flexible printed wiring board of any one of Claims.   The flexible printed wiring board according to claim 1, wherein the wiring width (c) is 20 μm or less.   6. The relationship of (d) / (c) ≦ 2.0 is established between the wiring width (c) of the wiring formed on the surface and the wiring interval (d). The flexible printed wiring board of Claim 1.   7. The wiring pattern according to claim 1, wherein a wiring pattern having a wiring width (c) and a wiring interval (d) of 20 μm or less is formed on the surface. The flexible printed wiring board as described.   Manufactured by a process including a process of forming a through hole in an insulating material, a process of forming a base metal layer, a process of performing electroplating, a process of forming a resist pattern, a process of etching, and a process of stripping the resist. The flexible printed wiring board of any one of Claims 1-7 characterized by the above-mentioned.   It is manufactured by a process including a process of forming a through hole in an insulating material, a process of forming a base metal layer, a process of forming a resist pattern, a process of performing electrolytic plating, a process of stripping a resist, and a process of performing flash etching. The flexible printed wiring board according to claim 1, wherein:   The flexible printed wiring board according to claim 8 or 9, wherein the step of forming the base metal layer comprises electroless plating.