JP2006282910A - Method for producing insulating film for printed wiring board and polyimide/copper laminated body and printed wiring board - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To rapidly increase the productivity of a thermoplastic polyimide resin having excellent adhesion to electroless plating and of the insulating film for printed wiring board laminated with high heat resistant polyimide film. <P>SOLUTION: In this method for producing insulating film for the printed wiring board, a layer (B) including a thermoplastic polyimide that is prepared from diamines containing a diamine represented by general formula (1) is coated on at least one surface of the layer (A) including high heat resistant polyimide to form the insulating film for the printed wiring board. At this time, a solution of high heat-resistance polyimide included in the layer (A) and a solution including thermoplastic polyimide included in the layer (B) or a solution including the precursor of the thermoplastic polyimide are used to carry out co-extrusion or film casting thereby producing insulating film for printed wiring board. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is a print in which a layer (B) containing a thermoplastic polyimide made from a diamine containing a diamine represented by the general formula (1) is provided on at least one side of a layer (A) containing a high heat resistant polyimide. The present invention relates to a method for producing and using a wiring board insulating film.

（式中、ｇは１以上の整数を表す。また、Ｒ¹は、同一または異なっていてよく、低級アルキレン基またはフェニレン基を表す。Ｒ²は、同一または異なっていてよく、低級アルキル基、またはフェニル基、またはフェノキシ基を表す。）

(In the formula, g represents an integer of 1 or more. Moreover, R ¹ may be the same or different and represents a lower alkylene group or a phenylene group. R ² may be the same or different and represents a lower alkyl group, Or a phenyl group or a phenoxy group.)

  Printed wiring boards are widely used for mounting electronic components, semiconductor elements, and the like. With recent demands for downsizing and higher functionality of electronic devices, there is a strong demand for higher density and thinner wiring. In particular, establishment of a fine wiring forming method in which the line / space spacing is 25 μm / 25 μm or less is an important issue in the field of printed wiring boards.

  In the case of fine wiring formation, the wiring shape, wiring width, wiring thickness, and the like cannot be satisfactorily formed as designed unless the unevenness on the surface of the insulating layer is made as small as possible. Alternatively, an etching residue is generated in the space portion of the wiring pattern. Further, since the area of contact between the circuit and the insulating layer is reduced by thinning, high adhesive strength is required.

  Thus, a preferable insulating layer for forming fine wiring is an insulating layer having extremely small surface irregularities and sufficiently high adhesion to the fine wiring.

  However, conventionally, the adhesion between the insulating layer and the wiring used in the wiring board has been achieved by surface unevenness called the anchor effect, as shown in (Patent Document 1), so the surface unevenness to be formed is reduced. Or, it was difficult to obtain a sufficient adhesive force with the wiring without forming irregularities.

On the other hand, regarding improvement in adhesion to wiring formed on a resin surface having a small surface roughness, (Patent Document 2) discloses a method of forming a conductor layer on a polyimide film surface by a physical method such as vapor deposition or sputtering. Yes. The formed metal layer has excellent adhesive strength as compared with a copper metal layer formed on the surface of a normal polyimide film. However, since the vacuum process is used, there are disadvantages that the cost is high and the productivity is inferior.
In addition, when the performance and speed of a semiconductor element are increased, the strength of the semiconductor element is reduced (becomes easy to break). The allowable range of deviation is also getting smaller.

In addition, in order to improve the overall strength, flexibility and dimensional stability of the film, the surface of the non-thermoplastic polyimide film rich in these properties can be improved in adhesion to the conductor layer forming the circuit wiring. It is conceivable to provide a layer. As a highly productive manufacturing method of such a multilayer polyimide film (Patent Document 3) and (Patent Document 4), a “non-thermoplastic polyimide layer and a thermoplastic polyimide layer are formed by simultaneous casting and coating” The “casting method” is disclosed, but there is no disclosure regarding that the copper plating adheres to a smooth resin surface with high adhesion strength.
JP2000-198907 JP-A-11-71474 Patent No. 2946416 JP-A-7-214636

  The present invention has been made in view of the above problems, and is an electroless plating capable of forming a conductor layer, particularly an extremely thin conductor layer suitable for forming a fine circuit, with high productivity, and adhesion between the conductor layer. The purpose of this method is to produce an insulating film for a printed wiring board that has high adhesion at the interface with the layer for improving the strength and is superior in strength, dimensional stability, and flexibility as compared with the conventional one. An object of the present invention is to provide a method for manufacturing such an excellent insulating film for printed wiring boards, which has dramatically high productivity.

  In addition, in such a multilayer polyimide film, the adhesion at the interface between the non-thermoplastic polyimide film and the layer for improving the adhesion between the conductor layer may not be sufficient, resulting in problems in heat resistance, etc. However, according to the production method of the present invention, the adhesion at the interface between the non-thermoplastic polyimide film and the layer for improving the adhesion between the conductor layers is improved.

As a result of intensive studies in view of the above-mentioned problems, the present inventors have independently developed a method for producing an insulating film for printed wiring boards excellent in adhesion, strength, flexibility, and dimensional stability of electroless plating, and its use. The present invention has been completed. That is, the present invention
(1) A layer (B) containing a thermoplastic polyimide using a diamine containing a diamine represented by the general formula (1) as a raw material is laminated on at least one side of the layer (A) containing a high heat resistant polyimide, A method for producing an insulating film for a printed wiring board, comprising a precursor solution of a high heat resistant polyimide contained in the layer (A) and a solution containing the thermoplastic polyimide contained in the layer (B) or a thermoplastic polyimide. A method for producing an insulating film for a printed wiring board, which is produced by a coextrusion-casting method using a solution containing a precursor,

（式中、ｇは１以上の整数を表す。また、Ｒ¹は、同一または異なっていてよく、低級アルキレン基またはフェニレン基を表す。Ｒ²は、同一または異なっていてよく、低級アルキル基、またはフェニル基、またはフェノキシ基を表す。）
（２）前記層（Ａ）に含まれる高耐熱性ポリイミドの前駆体溶液と、前記層（Ｂ）に含まれる熱可塑性ポリイミドを含有する溶液もしくは熱可塑性ポリイミドの前駆体を含有する溶液との少なくとも一方に化学脱水剤及び触媒を含むことを特徴とする、（１）に記載のプリント配線板用絶縁フィルムの製造方法、
（３）（１）もしくは（２）のいずれかに記載の方法により得られたプリント配線板用絶縁フィルムの層（Ｂ）の表面に無電解銅めっきを施すことを特徴とする、ポリイミド／銅積層体、
（４）（１）もしくは（２）のいずれかに記載の方法により得られたプリント配線板用絶縁フィルムまたは（３）に記載のポリイミド／銅積層体を用いることを特徴とするプリント配線板である。

(In the formula, g represents an integer of 1 or more. Moreover, R ¹ may be the same or different and represents a lower alkylene group or a phenylene group. R ² may be the same or different and represents a lower alkyl group, Or a phenyl group or a phenoxy group.)
(2) at least a precursor solution of a high heat-resistant polyimide contained in the layer (A) and a solution containing a thermoplastic polyimide or a solution containing a precursor of a thermoplastic polyimide contained in the layer (B) The method for producing an insulating film for a printed wiring board according to (1), which contains a chemical dehydrating agent and a catalyst on one side,
(3) Polyimide / copper, characterized in that electroless copper plating is applied to the surface of the layer (B) of the insulating film for printed wiring boards obtained by the method according to either (1) or (2) Laminate,
(4) A printed wiring board characterized by using the insulating film for a printed wiring board obtained by the method according to (1) or (2) or the polyimide / copper laminate according to (3). is there.

  As a result of intensive studies in view of the above-mentioned problems, the present inventors have independently developed a method for producing an insulating film for printed wiring boards excellent in adhesion, strength, flexibility, and dimensional stability of electroless plating, and its use. The present invention has been completed.

  According to the present invention, the adhesion of the interface between the electroless plating capable of forming a conductor layer, particularly an extremely thin conductor layer suitable for forming a fine circuit, with high productivity and the layer for improving the adhesion between the conductor layer. Insulating films for printed wiring boards that have high performance and superior strength, dimensional stability, and flexibility compared to conventional products can be manufactured with high productivity. As a result, printed wiring boards suitable for fine wiring can be manufactured. It can be provided. Moreover, the effect which improves the adhesiveness of the interface of a layer (A) and a layer (B) by laminating | stacking the high heat resistant polyimide contained in a layer (A) with a layer (B) in the state of a precursor solution is also effective. In particular, since the adhesiveness of the layer (A) and the layer (B) at high temperatures is improved, the heat resistance of the insulating film for printed wiring boards is also improved.

  Embodiments of the present invention will be described below.

  The insulating film for printed wiring boards according to the present invention comprises a layer containing a thermoplastic polyimide made from a diamine containing a diamine represented by the general formula (1) on at least one side of the layer (A) containing a high heat-resistant polyimide. (B) is provided.

（式中、ｇは１以上の整数を表す。また、Ｒ¹は、同一または異なっていてよく、低級アルキレン基またはフェニレン基を表す。Ｒ²は、同一または異なっていてよく、低級アルキル基、またはフェニル基、またはフェノキシ基を表す。）
本発明に係る高耐熱性ポリイミドを含む層（Ａ）は、そのプリント配線板用絶縁フィルムを用いて加工する際の工程、または最終製品の形態で通常さらされる温度において、容易に熱変形しないものであれば各種ポリイミド材料を使用して形成することができるが、特に非熱可塑性ポリイミド樹脂を９０ｗｔ％以上含有していることが好ましい。尚、その分子構造、厚みは特に限定されない。

(In the formula, g represents an integer of 1 or more. Moreover, R ¹ may be the same or different and represents a lower alkylene group or a phenylene group. R ² may be the same or different and represents a lower alkyl group, Or a phenyl group or a phenoxy group.)
The layer (A) containing the high heat-resistant polyimide according to the present invention is not easily thermally deformed at the temperature usually exposed in the process of using the insulating film for printed wiring boards or in the form of the final product. If it is, it can be formed using various polyimide materials, but it is preferable to contain 90 wt% or more of non-thermoplastic polyimide resin. The molecular structure and thickness are not particularly limited.

Hereinafter, description will be given based on an example of the embodiment.
(Layer containing highly heat-resistant polyimide (A))
Any known method can be used as a method for producing the polyamic acid as the precursor of the high heat-resistant polyimide used in the present invention. Usually, the aromatic acid dianhydride and the aromatic diamine are substantially equimolar amounts. Is dissolved in an organic solvent and the resulting solution is stirred under controlled temperature conditions until the polymerization of the acid dianhydride and diamine is complete. These polyamic acid solutions are usually obtained at a concentration of 5 to 35 wt%, preferably 10 to 30 wt%. When the concentration is within this range, an appropriate molecular weight and solution viscosity are easily obtained.

As the polymerization method, any known method and a combination thereof can be used. The characteristic of the polymerization method in the polymerization of polyamic acid is the order of addition of the monomers, and various physical properties of the high heat-resistant polyimide obtained can be controlled by controlling the order of addition of the monomers. Therefore, in the present invention, any method of adding monomers may be used for the polymerization of polyamic acid. The following method is mentioned as a typical polymerization method. That is,
1) A method in which an aromatic diamine is dissolved in an organic polar solvent and this is reacted with a substantially equimolar amount of an aromatic tetracarboxylic dianhydride for polymerization.
2) An aromatic tetracarboxylic dianhydride is reacted with a small molar amount of an aromatic diamine compound in an organic polar solvent to obtain a prepolymer having acid anhydride groups at both ends. Then, the method of superposing | polymerizing using an aromatic diamine compound so that an aromatic tetracarboxylic dianhydride and an aromatic diamine compound may become substantially equimolar in all the processes.
3) An aromatic tetracarboxylic dianhydride is reacted with an excess molar amount of an aromatic diamine compound in an organic polar solvent to obtain a prepolymer having amino groups at both ends. Subsequently, after adding an aromatic diamine compound here, using the aromatic tetracarboxylic dianhydride so that the aromatic tetracarboxylic dianhydride and the aromatic diamine compound are substantially equimolar in all steps. How to polymerize.
4) A method in which an aromatic tetracarboxylic dianhydride is dissolved and / or dispersed in an organic polar solvent and then polymerized using an aromatic diamine compound so as to be substantially equimolar.
5) A method in which a substantially equimolar mixture of aromatic tetracarboxylic dianhydride and aromatic diamine is reacted in an organic polar solvent for polymerization. And so on. These methods may be used singly or in combination.

  In the present invention, the polyamic acid obtained by using any of the above polymerization methods may be used, and the polymerization method is not particularly limited.

  In order to obtain a highly heat-resistant polyimide layer having physical properties suitable for use in an insulating film for a printed wiring board according to the present invention, a diamine component having a rigid structure typified by paraphenylenediamine or substituted benzidine is used. It is preferable to use a polymerization method for obtaining a prepolymer. By using this method, a polyimide film having a high elastic modulus and a small hygroscopic expansion coefficient tends to be easily obtained. The molar ratio of the diamine having a rigid structure and the acid dianhydride used in preparing the prepolymer in the present method is 100: 70 to 100: 99 or 70: 100 to 99: 100, and further 100: 75 to 100: 90 or 75: 100-90: 100 is preferable.

  Here, the material used suitably for the polyamic acid composition of the precursor of the high heat resistant polyimide which concerns on this invention is demonstrated.

  Suitable acid anhydrides that can be suitably used in the present invention include pyromellitic dianhydride, 2,3,6,7-naphthalenetetracarboxylic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic acid. Acid dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 2,2 ′, 3,3′-biphenyltetracarboxylic dianhydride, 3,3 ′, 4,4′-benzophenone Tetracarboxylic dianhydride, 4,4'-oxyphthalic dianhydride, 2,2-bis (3,4-dicarboxyphenyl) propane dianhydride, 3,4,9,10-perylenetetracarboxylic acid dianhydride Anhydride, bis (3,4-dicarboxyphenyl) propane dianhydride, 1,1-bis (2,3-dicarboxyphenyl) ethane dianhydride, 1,1-bis (3,4-dicarboxyphenyl) ) Ethane dianhydride, bis (2 , 3-dicarboxyphenyl) methane dianhydride, bis (3,4-dicarboxyphenyl) ethane dianhydride, oxydiphthalic dianhydride, bis (3,4-dicarboxyphenyl) sulfone dianhydride, p- Includes phenylene bis (trimellitic acid monoester acid anhydride), ethylene bis (trimellitic acid monoester acid anhydride), bisphenol A bis (trimellitic acid monoester acid anhydride) and the like, these alone Alternatively, a mixture of any ratio can be preferably used.

  In order to obtain a highly heat-resistant polyimide layer having physical properties suitable for use in the insulating film for printed wiring boards according to the present invention, among these acid dianhydrides, pyromellitic acid dianhydride and / or in particular. 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride and / or 4,4′-oxyphthalic dianhydride and / or 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride And / or p-phenylenebis (trimellitic acid monoester anhydride) is preferred.

  Suitable diamines that can be suitably used in the polyamic acid composition of the precursor of the high heat resistant polyimide according to the present invention include 1,4-diaminobenzene (p-phenylenediamine), 1,3-diaminobenzene, 1, 2-diaminobenzene, 4,4′-diaminodiphenylpropane, 4,4′-diaminodiphenylmethane, 3,3′-dichlorobenzidine, 3,3′-dimethylbenzidine, 2,2′-dimethylbenzidine, 3,3 ′ -Dimethoxybenzidine, 2,2'-dimethoxybenzidine, 3,3'-dihydroxybenzidine, 4,4'-diaminodiphenyl sulfide, 3,3'-diaminodiphenylsulfone, 4,4'-diaminodiphenylsulfone, 4,4 '-Oxydianiline, 3,3'-oxydianiline, 3,4'-oxydianiline, 1,5-dia Nonaphthalene, 4,4'-diaminodiphenyldiethylsilane, 4,4'-diaminodiphenylsilane, 4,4'-diaminodiphenylethylphosphine oxide, 4,4'-diaminodiphenyl N-methylamine, 4,4'- Diaminodiphenyl N-phenylamine, bis {4- (4-aminophenoxy) phenyl} sulfone, bis {4- (3-aminophenoxy) phenyl} sulfone, 4,4′-bis (4-aminophenoxy) biphenyl, 4,4′-bis (3-aminophenoxy) biphenyl, 1,3-bis (3-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) benzene, 1,3-bis (4-aminophenoxy) ) Benzene, 1,3-bis (3-aminophenoxy) benzene, 3,3′-diaminobenzophenone, 4, '- such as diamino benzophenone and their analogs thereof.

  If these diamines are classified into so-called rigid diamines such as diaminobenzenes and benzidines and diamines having flexible structures such as ether groups, sulfone groups, ketone groups and sulfide groups, rigid structures and flexible diamines are considered. The use ratio of the structural diamine is 80/20 to 20/80, preferably 70/30 to 30/70, particularly preferably 60/40 to 30/70, in molar ratio. If the use ratio of the rigid diamine exceeds the above range, the tensile elongation of the resulting layer tends to be small, and if it falls below this range, the glass transition temperature becomes too low or the storage modulus during heat decreases. In some cases, film formation becomes difficult.

  Although the high heat-resistant polyimide contained in the layer (A) used in the present invention is not limited to the above range, an aromatic acid is appropriately used so that the layer has desired characteristics within the above range. It is particularly preferable to determine and use the dianhydride and aromatic diamine, and the mixing ratio.

  As the preferred solvent for synthesizing the polyamic acid, any solvent that dissolves the polyamic acid can be used. For example, sulfoxide solvents such as dimethyl sulfoxide and diethyl sulfoxide, N, N-dimethylformamide, N, Formamide solvents such as N-diethylformamide, N, N-dimethylacetamide, acetamide solvents such as N, N-diethylacetamide, pyrrolidone solvents such as N-methyl-2-pyrrolidone and N-vinyl-2-pyrrolidone, Phenol solvents such as phenol, o-, m-, or p-cresol, xylenol, halogenated phenol, catechol, ether solvents such as tetrahydrofuran, dioxane, dioxolane, alcohol solvents such as methanol, ethanol, butanol Examples include cellosolve such as butyl cellosolve, hexamethylphosphoramide, γ-butyrolactone, etc., and these are preferably used alone or as a mixture, but aromatic hydrocarbons such as xylene and toluene can also be used. is there. Among these, formamide solvents such as N, N-dimethylformamide and N, N-diethylformamide can be particularly preferably used. Also, water should be removed as much as possible to promote the degradation of the polyamic acid.

  In addition, a filler can be added for the purpose of improving various properties of the film such as blocking property improvement, slidability, thermal conductivity, conductivity, corona resistance, loop stiffness, dimensional stability and strength. Any filler may be used, but preferred examples include silica, titanium oxide, alumina, silicon nitride, boron nitride, calcium hydrogen phosphate, calcium phosphate, mica and the like.

The particle size of the filler is not particularly limited because it is determined by the film characteristics to be modified and the type of filler to be added, but generally the average particle size is 0.05 to 20 μm, preferably 0.1. -15 μm, more preferably 0.1-10 μm, particularly preferably 0.1-5 μm. If the particle size is below this range, the modification effect is less likely to appear. If the particle size is above this range, the surface properties may be greatly impaired or the mechanical properties may be greatly deteriorated. Further, the number of added parts of the filler is not particularly limited because it is determined by the film properties to be modified, the filler particle diameter, and the like. However, generally the addition amount of a filler is 0.01-100 weight part with respect to 100 weight part of polyimide, Preferably it is 0.01-90 weight part, More preferably, it is 0.02-80 weight part. If the amount of filler added is less than this range, the effect of modification by the filler hardly appears, and if it exceeds this range, the mechanical properties of the film may be greatly impaired. Addition of filler
1. 1. A method of adding to a polymerization reaction solution before or during polymerization 2. A method of kneading fillers using three rolls after the completion of polymerization. Any method such as preparing a dispersion containing filler and mixing it with a polyamic acid organic solvent solution may be used, but a method of mixing a dispersion containing filler with a polyamic acid solution, particularly immediately before film formation. This method is preferable because the contamination by the filler in the production line is minimized. When preparing a dispersion containing a filler, it is preferable to use the same solvent as the polymerization solvent for the polyamic acid. Moreover, in order to disperse | distribute a filler favorably and stabilize a dispersion state, a dispersing agent, a thickener, etc. can also be used in the range which does not affect a film physical property. In addition, a small amount of a polymerization reaction solution (polyamic acid solution) may be added to the filler dispersion to prevent the filler from aggregating when the dispersion is added to the polymerization reaction solution. The layer (A) preferably contains 50% or more of the high heat resistant polyimide with respect to the total weight of the layer (A) in order to fully express the characteristics of the high heat resistant polyimide.
(Layer containing thermoplastic polyimide (B))
As the thermoplastic polyimide contained in the layer (B), it is essential to use a diamine containing the diamine represented by the general formula (1) as a raw material.

（式中、ｇは１以上の整数を表す。また、Ｒ¹は、同一または異なっていてよく、低級アルキレン基またはフェニレン基を表す。Ｒ²は、同一または異なっていてよく、低級アルキル基、またはフェニル基、またはフェノキシ基を表す。）
この熱可塑性ポリイミドの前駆体のポリアミド酸についても、層(Ａ)に用いる高耐熱性ポリイミドと同様に、種々の特性を改善するためにフィラーやその他の添加物を用いることや、ポリアミド酸の製造に関して、公知の原料や反応条件等を用いることができる（例えば、後述する実施例参照）。また、必要に応じて一般式（１）で表されるジアミンを含むジアミンを原料とする熱可塑性ポリイミドの前駆体溶液とその他のポリイミドの前駆体溶液を混合して用いることも可能である。

(In the formula, g represents an integer of 1 or more. Moreover, R ¹ may be the same or different and represents a lower alkylene group or a phenylene group. R ² may be the same or different and represents a lower alkyl group, Or a phenyl group or a phenoxy group.)
As for the polyamic acid which is a precursor of this thermoplastic polyimide, like the high heat-resistant polyimide used for the layer (A), fillers and other additives may be used to improve various properties, and the polyamic acid may be produced. As for, known raw materials, reaction conditions, and the like can be used (for example, see Examples described later). Moreover, it is also possible to mix and use the precursor solution of the thermoplastic polyimide which uses the diamine containing the diamine represented by General formula (1) as a raw material as needed, and the precursor solution of another polyimide.

（式中、ｇは１以上の整数を表す。また、Ｒ¹は、同一または異なっていてよく、低級アルキレン基またはフェニレン基を表す。Ｒ²は、同一または異なっていてよく、低級アルキル基、またはフェニル基、またはフェノキシ基を表す。）
また、一般式（１）で表されるジアミンを含むジアミンを原料とする熱可塑性ポリイミドの前駆体溶液を、事前に熱的方法あるいは化学的方法あるいは熱的方法と化学的方法を組み合わせた方法によりイミド化し、その熱可塑性ポリイミドを有機溶剤に溶解したポリイミド溶液を本発明に適用することも可能である。

(In the formula, g represents an integer of 1 or more. Moreover, R ¹ may be the same or different and represents a lower alkylene group or a phenylene group. R ² may be the same or different and represents a lower alkyl group, Or a phenyl group or a phenoxy group.)
Further, a precursor solution of a thermoplastic polyimide using a diamine containing the diamine represented by the general formula (1) as a raw material is obtained by a thermal method, a chemical method, or a combination of a thermal method and a chemical method in advance. A polyimide solution obtained by imidization and dissolving the thermoplastic polyimide in an organic solvent can also be applied to the present invention.

（式中、ｇは１以上の整数を表す。また、Ｒ¹は、同一または異なっていてよく、低級アルキレン基またはフェニレン基を表す。Ｒ²は、同一または異なっていてよく、低級アルキル基、またはフェニル基、またはフェノキシ基を表す。）
また，これらの層（Ｂ）を形成するための溶液に、その特性を損なわない範囲で無機物あるいは有機物のフィラーやその他の添加剤、樹脂成分等を添加しても良い。
層(Ｂ)は導体層との密着性を向上するための層としての特性を十分発現するために、層(Ｂ)の全重量に対し、一般式（１）で表されるジアミンを含むジアミンを原料とする熱可塑性ポリイミドを５０％以上含有することが好ましい。

(In the formula, g represents an integer of 1 or more. Moreover, R ¹ may be the same or different and represents a lower alkylene group or a phenylene group. R ² may be the same or different and represents a lower alkyl group, Or a phenyl group or a phenoxy group.)
In addition, inorganic or organic fillers, other additives, resin components, and the like may be added to the solution for forming these layers (B) as long as the properties are not impaired.
The layer (B) is a diamine containing the diamine represented by the general formula (1) with respect to the total weight of the layer (B) in order to fully express the characteristics as a layer for improving the adhesion to the conductor layer. It is preferable to contain 50% or more of a thermoplastic polyimide made from a raw material.

(Method for producing insulating film for printed wiring board of the present invention)
Here, the manufacturing method of the insulating film for printed wiring boards according to the present invention uses, as a raw material, a diamine containing the diamine represented by the general formula (1) on at least one surface of the layer (A) containing the high heat-resistant polyimide. A method for producing an insulating film for a printed wiring board by laminating a layer (B) containing a thermoplastic polyimide, comprising a precursor solution of a high heat-resistant polyimide contained in the layer (A), and the layer (B) It is essential to manufacture by a coextrusion-casting method using a solution containing a thermoplastic polyimide contained in or a solution containing a precursor of a thermoplastic polyimide.

  The coextrusion-casting method according to the present invention is a method comprising two or more layers of a highly heat-resistant polyimide precursor solution and a solution containing a thermoplastic polyimide or a solution containing a thermoplastic polyimide precursor. It is a method for producing a film including a step of simultaneously supplying to an extrusion molding machine having an extrusion die and extruding both solutions as at least two layers of thin film bodies from the discharge port of the die. A generally used method will be described. Both solutions extruded from two or more extrusion dies are continuously extruded onto a smooth support, and then a multilayer thin film on the support is formed. By volatilizing at least part of the body solvent, a multilayer film having self-supporting properties can be obtained. Further, the multilayer film is peeled off from the support, and the multilayer film is heat-treated to substantially remove the solvent and advance imidization, thereby obtaining a target insulating film for printed wiring board. It is done. Further, for the purpose of improving the melt fluidity and adhesion of the layer (B), the imidization rate may be intentionally lowered and / or the solvent may be left.

  Particularly limited with respect to the method of volatilization of the solvent in the precursor solution of the high heat-resistant polyimide extruded from the die for extrusion molding of two or more layers and the solution containing the thermoplastic polyimide or the precursor of the thermoplastic polyimide Although not, the method by heating and / or blowing is the simplest method. If the temperature of the heating is too high, the solvent is volatilized rapidly, and the trace of the volatilization becomes a factor for forming minute defects in the insulating film for printed wiring boards, so the boiling point of the solvent used + 50 ° C. It is preferable that it is less than.

  As the above-mentioned two or more layers of extrusion-molding dies, those having various structures can be used. For example, a T-die for forming a multi-layer film can be used. In addition, any conventionally known structure can be suitably used, but feed block T dice and multi-manifold T dice are exemplified as those that can be particularly suitably used.

（式中、ｇは１以上の整数を表す。また、Ｒ¹は、同一または異なっていてよく、低級アルキレン基またはフェニレン基を表す。Ｒ²は、同一または異なっていてよく、低級アルキル基、またはフェニル基、またはフェノキシ基を表す。）
一般的にポリイミドは、ポリイミドの前駆体、即ちポリアミド酸からの脱水転化反応により得られ、当該転化反応を行う方法としては、熱によってのみ行う熱的方法と、化学脱水剤を使用する化学的方法，あるいは熱的方法と化学的方法を組み合わせる方法が広く知られている。
従って、本発明に係るプリント配線板用絶縁フィルムの製造方法は、高耐熱性ポリイミド層かつ／または熱可塑性ポリイミド層を、化学キュア法を用いて形成せしめることを含む。化学キュア法は、熱キュア法に比して、ポリイミド樹脂の製造に際し、飛躍的に高い生産性を付与する。

(In the formula, g represents an integer of 1 or more. Moreover, R ¹ may be the same or different and represents a lower alkylene group or a phenylene group. R ² may be the same or different and represents a lower alkyl group, Or a phenyl group or a phenoxy group.)
In general, polyimide is obtained by a dehydration conversion reaction from a polyimide precursor, that is, a polyamic acid. As a method for performing the conversion reaction, a thermal method using only heat and a chemical method using a chemical dehydrating agent are used. Or a combination of thermal and chemical methods is widely known.
Therefore, the manufacturing method of the insulating film for printed wiring boards which concerns on this invention includes forming a high heat resistant polyimide layer and / or a thermoplastic polyimide layer using a chemical curing method. The chemical curing method provides dramatically higher productivity in the production of polyimide resin than the thermal curing method.

  As the chemical dehydrating agent according to the present invention, dehydrating ring-closing agents for various polyamic acids can be used, but aliphatic acid anhydrides, aromatic acid anhydrides, N, N′-dialkylcarbodiimides, lower aliphatic halides, halogenated compounds. Lower aliphatic acid anhydrides, aryl sulfonic acid dihalides, thionyl halides or mixtures of two or more thereof can be preferably used. Of these, aliphatic acid anhydrides and aromatic acid anhydrides work particularly well. In addition, the term “catalyst” refers to a component that has an effect of promoting the dehydration ring-closing action of a chemical dehydrating agent on polyamic acid. For example, an aliphatic tertiary amine, an aromatic tertiary amine, or a heterocyclic tertiary amine is used. be able to. Of these, nitrogen-containing heterocyclic compounds such as imidazole, benzimidazole, isoquinoline, quinoline, and β-picoline are particularly preferable.

  The preferable amount of the chemical dehydrating agent is 0.5 to 5 mol, preferably 0.7 to 4 mol, based on 1 mol of the amic acid unit in the polyamic acid contained in the solution containing the chemical dehydrating agent and the catalyst. . Moreover, the preferable amount of a catalyst is 0.05-3 mol with respect to 1 mol of amic acid units in the polyamic acid contained in the solution which contains a chemical dehydrating agent and a catalyst, Preferably it is 0.2-2 mol. . If the dehydrating agent and the catalyst are below the above ranges, chemical imidization may be insufficient, and may break during firing or mechanical strength may decrease. Moreover, when these amounts exceed the above range, the progress of imidization becomes too fast and it may be difficult to cast into a film.

  One of the preferred embodiments of the finally obtained insulating film for printed wiring boards is to form a conductor layer on at least one surface by electroless plating.

  About the thickness constitution of each layer of the insulating film for printed wiring board, it may be adjusted as appropriate so as to be the total thickness according to the use, but the tensile elastic modulus in the longitudinal direction and the width direction of the obtained insulating film for printed wiring board is It is preferable that the pressure is 5.0 to 11 GPa, preferably 5.5 to 10 GPa. When the tensile elastic modulus is lower than the above range, it becomes easy to be affected by tension in the roll-to-roll conveyance process, so that different stresses are generated in the MD direction and the TD direction, and the resulting flexible metal-clad laminate has a dimensional change. May be larger. Conversely, if the tensile modulus exceeds the above range, the resulting insulating film for printed wiring board may be inferior in flexibility. Generally, since the tensile elastic modulus of the adhesive layer is smaller than that of the high heat resistant polyimide layer, the tensile elastic modulus of the insulating film for printed wiring board tends to decrease as the thickness ratio of the adhesive layer increases.

  In addition, if the difference between the thermal expansion coefficient of the insulating film for printed wiring boards and the thermal expansion coefficient of the metal layer that forms the conductor layer increases, the difference in expansion / contraction behavior during bonding increases, resulting in the obtained flexible In some cases, strain remains in the metal-clad laminate, and the dimensional change rate after removal of the metal foil may increase. The thermal expansion coefficient of the insulating film for printed wiring boards is preferably adjusted so that the value at 200 to 300 ° C. is in the range of the thermal expansion coefficient ± 6 ppm / ° C. of the metal foil. The thermal expansion coefficient of the insulating film for printed wiring boards can be adjusted by changing the thickness ratio between the high heat-resistant polyimide layer and the adhesive layer.

  Moreover, the insulating film for printed wiring boards of this invention is a layer (B) containing the thermoplastic polyimide which uses as a raw material the diamine containing the diamine represented by General formula (1) on the one side of a highly heat-resistant polyimide film. It is also possible to have a configuration in which an adhesive layer is laminated on the other surface of the multilayer printed wiring board.

（式中、ｇは１以上の整数を表す。また、Ｒ¹は、同一または異なっていてよく、低級アルキレン基またはフェニレン基を表す。Ｒ²は、同一または異なっていてよく、低級アルキル基、またはフェニル基、またはフェノキシ基を表す。）

(In the formula, g represents an integer of 1 or more. Moreover, R ¹ may be the same or different and represents a lower alkylene group or a phenylene group. R ² may be the same or different and represents a lower alkyl group, Or a phenyl group or a phenoxy group.)

  Next, the manufacturing method of the insulating film for printed wiring boards which concerns on this invention is demonstrated in detail by an Example.

(Synthesis Example 1; Synthesis of Polyamic Acid as Precursor of High Heat-Resistant Polyimide)
239 kg of N, N-dimethylformamide (hereinafter also referred to as DMF) cooled to 10 ° C., 6.9 kg of 4,4′-oxydianiline (hereinafter also referred to as ODA), p-phenylenediamine (hereinafter also referred to as p-PDA) After dissolving 9.4 kg of 2,2-bis [4- (4-aminophenoxy) phenyl] propane (hereinafter also referred to as BAPP) 6.2 kg, pyromellitic dianhydride (hereinafter also referred to as PMDA). ) 10.4 kg was added and dissolved by stirring for 1 hour. To this, 20.3 kg of benzophenone tetracarboxylic dianhydride (hereinafter also referred to as BTDA) was added and dissolved by stirring for 1 hour.

  A separately prepared DMF solution of PMDA (PMDA: DMF = 0.9 kg: 7.0 kg) was gradually added to the reaction solution, and the addition was stopped when the viscosity reached about 3000 poise. Stirring was performed for 1 hour to obtain a polyamic acid solution of a precursor of a high heat-resistant polyimide having a solid content concentration of 18% by weight and a rotational viscosity at 23 ° C. of 3500 poise.

(Synthesis Example 2: Synthesis of polyamic acid as a precursor of high heat-resistant polyimide)
After dissolving 12.6 kg of ODA and 6.8 kg of p-PDA in 239 kg of DMF cooled to 10 ° C., 15.6 kg of PMDA was added and stirred for 1 hour to dissolve. Subsequently, 12.2 kg of BTDA was added and stirred for 1 hour to dissolve. To this, 5.8 kg of p-phenylenebis (trimellitic acid monoester acid anhydride) (hereinafter also referred to as TMHQ) was added and dissolved by stirring for 2 hours.

  A separately prepared DMF solution of PMDA (PMDA: DMF = 0.9 kg: 7.0 kg) was gradually added to the reaction solution, and the addition was stopped when the viscosity reached about 3000 poise. Stirring was performed for 1 hour to obtain a polyamic acid solution of a precursor of a high heat-resistant polyimide having a solid content concentration of 18% by weight and a rotational viscosity at 23 ° C. of 3500 poise.

(Synthesis Example 3; Synthesis of Polyamic Acid as Precursor of High Heat-Resistant Polyimide)
After 21.1 kg of ODA was dissolved in 232 kg of DMF cooled to 10 ° C., 30.6 kg of PMDA was added and dissolved by stirring for 1 hour. To this, 3.78 kg of p-PDA was added and stirred for 1 hour to dissolve.

  A separately prepared DMF solution of p-PDA (p-PDA: DMF = 3.78 kg: 38.0 kg) was gradually added to the reaction solution, and the addition was stopped when the viscosity reached about 3000 poise. . Stirring was performed for 1 hour to obtain a polyamic acid solution of a precursor of a highly heat-resistant polyimide having a solid content concentration of 18% by weight and a rotational viscosity at 23 ° C. of 3400 poise.

(Synthesis Example 4: Synthesis of polyamic acid as precursor of thermoplastic polyimide)
To 1,3,3,3-tetramethyl-1,3-bis (3-aminopropyl) disiloxane (34.9 kg) and 4,4'-diaminodiphenyl ether (8.4 kg) were added to DMF (203 kg) cooled to 10 ° C. Stir for 1 hour to dissolve. To this, 43.7 kg of 4,4 ′-(4,4′-isopropylidenediphenoxy) bisphthalic anhydride was added and stirred for 1 hour to obtain a DMF solution of polyamic acid having a solid content concentration of 30%.

(Synthesis Example 5: Synthesis of polyamic acid as precursor of thermoplastic polyimide)
To 2,204 kg of 1,1,3,3-tetramethyl-1,3-bis (3-aminopropyl) disiloxane and 13.4 kg of 4,4′-oxydianiline were added to 204 kg of DMF cooled to 10 ° C. Stir for 1 hour to dissolve, add 50.0 kg of 4,4 ′-(4,4′-isopropylidenediphenoxy) bisphthalic anhydride, stir for 1 hour, and polyamic acid with a solid content of 30% Of DMF was obtained.

(Synthesis Example 6; Synthesis of Polyamic Acid as Precursor of Thermoplastic Polyimide)
33.5 kg of 2,2-bis [4- (4-aminophenoxy) phenyl] propane (BAPP) was added to 226 kg of DMF cooled to 10 ° C., and while stirring under a nitrogen atmosphere, 3,3 ′, 4,4 22.8 kg of '-biphenyltetracarboxylic dianhydride (BPDA) was gradually added. Subsequently, 1.1 kg of ethylenebis (trimellitic acid monoester acid anhydride) (TMEG) was added, and a solution in which 0.6 kg of TMEG was dissolved in 5.8 kg of DMF was separately prepared. The solution was gradually added and stirred while paying attention to the viscosity. When the viscosity reached 3000 poise, addition and stirring were stopped to obtain a polyamic acid solution as a precursor of thermoplastic polyimide having a solid content concentration of 20%.
(Synthesis Example 7: Synthesis of thermoplastic polyimide solution)
The polyamic acid solution obtained in Synthesis Example 4 was placed in a vat coated with Teflon (registered trademark) and heated under reduced pressure at 665 Pa at 200 ° C. for 120 minutes in a vacuum oven to obtain a thermoplastic polyimide resin. The obtained thermoplastic polyimide was dissolved in DMF to obtain a thermoplastic polyimide solution having a solid content concentration of 10%.

Example 1
The following chemical dehydrating agent and catalyst were contained in the polyamic acid solution of the precursor of the high heat-resistant polyimide obtained in Synthesis Example 1.
1. Chemical dehydrating agent: 2 moles per mole of amic acid unit of polyamic acid which is a precursor of high heat resistant polyimide with acetic anhydride 2. Catalyst: 1 mol of isoquinoline with respect to 1 mol of polyamic acid amic acid unit as a precursor of high heat-resistant polyimide. Further, using a polyamic acid solution of a precursor of thermoplastic polyimide obtained in Synthesis Example 4, a three-layer multi-layer From the manifold T die, each polyamic acid solution is continuously extruded in the order that the outer layer is the polyamic acid solution of the precursor of the thermoplastic polyimide and the inner layer is the polyamic acid solution of the precursor of the high heat-resistant polyimide solution. It was cast on a stainless steel endless belt running 20 mm below the die. The resin film is heated at 130 ° C. for 100 seconds, and then the self-supporting gel film is peeled off from the endless belt and fixed to the tenter clip. At 300 ° C. for 30 seconds, 400 ° C. for 50 seconds, 450 ° C. for 10 seconds. It was made to dry and imidize and the insulating film for printed wiring boards of each thermoplastic polyimide layer 2 micrometers and the high heat resistant polyimide layer 10 micrometers was obtained.

(Example 2)
The same procedure as in Example 1 except that the polyamic acid solution of the precursor of the high heat resistance polyimide obtained in Synthesis Example 2 was used instead of the polyamic acid solution of the precursor of the high heat resistance polyimide obtained in Synthesis Example 1. Thus, an insulating film for a printed wiring board was produced.

(Example 3)
A procedure similar to that in Example 1 except that the polyamic acid solution of the precursor of the high heat resistance polyimide obtained in Synthesis Example 3 was used instead of the polyamic acid solution of the precursor of the high heat resistance polyimide obtained in Synthesis Example 1. Thus, an insulating film for printed wiring board was produced.

Example 4
An insulating film for a printed wiring board was prepared in the same procedure as in Example 1 except that the thermoplastic polyimide solution obtained in Synthesis Example 5 was used instead of the polyamic acid solution of the thermoplastic polyimide precursor obtained in Synthesis Example 4. Produced.

(Example 5)
An insulating film for printed wiring board was prepared in the same manner as in Example 1 except that the thermoplastic polyimide solution obtained in Synthesis Example 7 was used instead of the polyamic acid solution of the precursor of thermoplastic polyimide obtained in Synthesis Example 4. Produced.

(Example 6)
The polyamic acid solution of the precursor of the high heat-resistant polyimide obtained in Synthesis Example 1 and the polyamic acid solution of the precursor of the thermoplastic polyimide obtained in Synthesis Example 4 are heated from the three-layer multi-manifold T die and the outer layer is heated. Each polyamic acid solution is continuously extruded in the order in which the polyamic acid solution of the precursor of the plastic polyimide and the inner layer become the polyamic acid solution of the precursor of the high heat resistant polyimide solution, and run under 20 mm under the T die. Cast on a stainless steel endless belt. After heating this resin film at 130 ° C. × 600 seconds, the self-supporting gel film is peeled off from the endless belt and fixed to the tenter clip, and 200 ° C. × 300 seconds, 300 ° C. × 300 seconds, 400 ° C. × 300 seconds. The film was dried and imidized at 450 ° C. for 60 seconds (heating time: 1560 seconds in total) to obtain the intended insulating film for printed wiring board.

(Comparative Example 1)
An insulating film for a printed wiring board was prepared in the same procedure as in Example 6 except that the thermoplastic polyimide solution obtained in Synthesis Example 6 was used instead of the polyamic acid solution of the precursor of thermoplastic polyimide obtained in Synthesis Example 4. Produced.

(Comparative Example 2)
The following chemical dehydrating agent and catalyst were contained in the polyamic acid solution of the precursor of the high heat-resistant polyimide obtained in Synthesis Example 1.
1. Chemical dehydrating agent: 2 moles per mole of amic acid unit of polyamic acid which is a precursor of high heat resistant polyimide with acetic anhydride 2. Catalyst: 1 mol of isoquinoline with respect to 1 mol of amic acid unit of polyamic acid which is a precursor of high heat resistant polyimide. Further, a polyamic acid solution which is a precursor of the obtained high heat resistant polyimide solution is continuously extruded from a T-die. Then, it was cast on a stainless steel endless belt running 20 mm below the T die. After heating this resin film at 130 ° C. × 600 seconds, the self-supporting gel film is peeled off from the endless belt and fixed to the tenter clip, and 200 ° C. × 300 seconds, 300 ° C. × 300 seconds, 400 ° C. × 300 seconds. The film was dried and imidized at 450 ° C. for 60 seconds (heating time: 1560 seconds in total) to obtain a highly heat-resistant polyimide film (thickness 10 microns).

  The polyamic acid solution of the thermoplastic polyimide precursor obtained in Synthesis Example 4 was applied to both sides of the obtained polyimide film so that the thickness after drying was 2 microns, and the temperature was 1 minute at 390 ° C. for 2 minutes at 150 ° C. A thermoplastic polyimide layer was formed by heating for a minute to obtain an insulating film for a printed wiring board.

(Comparative Example 3)
The thermoplastic polyimide precursor solution obtained in Synthesis Example 4 was applied so that the thickness after drying was 2 microns, and the thermoplastic polyimide layer was heated at 150 ° C. for 2 minutes and 390 ° C. for 1 minute. Insulating film for printed wiring board in the same procedure as Comparative Example 2 except that the thermoplastic polyimide solution obtained in Synthesis Example 7 is applied to a high heat resistant polyimide film and dried at 150 ° C. for 2 minutes. Got.

  Insulating films for printed wiring boards obtained in Examples 1 to 6 and Comparative Examples 1 to 3 were processed under the conditions shown in Table 1 below, and electroless copper plating and electrolytic copper plating were applied, and a conductor was formed on the insulating film. A layer (18 microns thick) was formed to produce a polyimide / copper laminate.

得られた、ポリイミド／銅積層体を、１８０℃、３０分の乾燥処理を行った後、ＪＰＣＡ−ＢＵ０１−１９９８（社団法人日本プリント回路工業会発行）に従い、常態、及びプレッシャークッカー試験（ＰＣＴ）後の接着強度を測定した。
常態接着強度：２５℃、５０％の雰囲気下、２４時間放置した後に測定した接着強度。
ＰＣＴ後接着強度：１２１℃、１００％の雰囲気下、９６時間放置した後に測定した接着強度。

The obtained polyimide / copper laminate was dried at 180 ° C. for 30 minutes, and then subjected to normal and pressure cooker tests (PCT) according to JPCA-BU01-1998 (issued by the Japan Printed Circuits Association). The subsequent adhesive strength was measured.
Normal-state adhesive strength: Adhesive strength measured after standing for 24 hours in an atmosphere of 25 ° C. and 50%.
Adhesive strength after PCT: Adhesive strength measured after standing for 96 hours in an atmosphere of 121 ° C. and 100%.

  Also, after the polyimide / copper laminate obtained above was dried at 180 ° C. for 30 minutes, a sample cut into a size of 15 mm × 30 mm was left in an environment of 23 ° C. and 50% for 24 hours, and then heated in a hot air oven. Heat at 10 ° C. for 10 seconds. The appearance of the sample after heating was observed to determine whether the conductor layer was swollen.

  The obtained results are shown in (Table 2).

この表から明らかなように、共押出−流延塗布法により製造した、高耐熱性ポリイミド層（Ａ）と一般式（１）で表されるジアミンを含むジアミンを原料とする熱可塑性ポリイミド樹脂を含有する層（Ｂ）とを積層してなるプリント配線板用絶縁フィルムは、めっき銅と熱可塑性ポリイミド樹脂の常態およびＰＣＴ後の接着強度が高く、かつはんだリフロー工程のために必要な２６０℃の耐熱性を兼ね備えており、プリント配線板用絶縁フィルムとして好適である。

As is apparent from this table, a thermoplastic polyimide resin produced by a coextrusion-casting coating method and made from a diamine containing a diamine represented by the general heat-resistant polyimide layer (A) and the general formula (1) is used. The insulating film for printed wiring boards formed by laminating the containing layer (B) has a normal state of plated copper and a thermoplastic polyimide resin and a high adhesive strength after PCT, and has a 260 ° C. necessary for the solder reflow process. It has heat resistance and is suitable as an insulating film for printed wiring boards.

Claims (4)

A layer (B) containing a thermoplastic polyimide using a diamine containing a diamine represented by the general formula (1) as a raw material is laminated on at least one side of the layer (A) containing a high heat resistant polyimide, and a printed wiring board A method for producing an insulating film for a high temperature heat-resistant polyimide precursor solution contained in the layer (A) and a solution containing the thermoplastic polyimide contained in the layer (B) or a thermoplastic polyimide precursor. The manufacturing method of the insulating film for printed wiring boards manufactured by the coextrusion-casting coating method using the solution to contain.

(In the formula, g represents an integer of 1 or more. Moreover, R ¹ may be the same or different and represents a lower alkylene group or a phenylene group. R ² may be the same or different and represents a lower alkyl group, Or a phenyl group or a phenoxy group.) Chemically at least one of the precursor solution of the high heat-resistant polyimide contained in the layer (A) and the solution containing the thermoplastic polyimide or the solution containing the precursor of the thermoplastic polyimide contained in the layer (B). The method for producing an insulating film for a printed wiring board according to claim 1, comprising a dehydrating agent and a catalyst.   A polyimide / copper laminate, wherein the surface of the layer (B) of the insulating film for printed wiring boards obtained by the method according to claim 1 or 2 is subjected to electroless copper plating.   A printed wiring board comprising the insulating film for a printed wiring board obtained by the method according to claim 1 or the polyimide / copper laminate according to claim 3.