JP2003008157A - Wiring circuit board and base therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a base of a wiring circuit board, which makes it possible to effectively prevent warpage and variation in dimensions and is efficiently manufactured without increase in man-hours, and to provide a wiring circuit board using the base for wiring circuit board. SOLUTION: A resin composition of a base containing a polyimide resin precursor and a tertiary amine compound is prepared and applied to metal foil 1. The resin composition is then dried and cured to form a base insulating film 3, thereby obtaining a two-layered base 4. The metal foil 1 of the two- layered base 4 is patterned into a desired wiring circuit pattern to obtain a wiring circuit board 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wiring circuit board base material and a wiring circuit board, and more specifically, a wiring circuit board suitably used as a flexible wiring circuit board used in electronic parts and electronic equipment, and the like. The present invention relates to a printed circuit board base material used for manufacturing a printed circuit board.

[0002]

2. Description of the Related Art Conventionally, a wiring circuit board such as a flexible wiring circuit board is prepared by, for example, first applying a solution of a polyimide resin precursor such as polyamic acid resin on a copper foil and then curing it after curing (imidization). ) To produce a two-layer base material, and then etching the copper foil of the two-layer base material by a known patterning method such as a subtractive method to form a predetermined wiring circuit pattern. Has been done.

[0003]

However, in the printed circuit board thus manufactured, the copper foil of the two-layer base material is
After patterning into a predetermined wiring circuit pattern, there is a problem that warpage or dimensional change easily occurs.

Therefore, for example, Japanese Unexamined Patent Publication No. 8-25086
No. 0 publication proposes manufacturing a printed circuit board having no warp and good dimensional stability by forming a plurality of polyimide resin precursor layers having different linear expansion coefficients as multilayers on a copper foil. ing.

However, in the method described in Japanese Patent Application Laid-Open No. 8-250860, since it is necessary to laminate the polyimide resin precursors having different linear expansion coefficients a plurality of times, the number of steps is increased and it takes a lot of labor. Therefore, a problem occurs that efficient production cannot be realized.

The present invention has been made in view of the above problems, and an object thereof is to effectively prevent the occurrence of warpage and dimensional change, and to avoid unnecessary man-hours. Another object of the present invention is to provide a wiring circuit board base material and a wiring circuit board using the wiring circuit board base material, which can realize efficient production.

[0007]

In order to achieve the above object, a substrate for a printed circuit board of the present invention is a resin composition for a substrate containing a polyimide resin precursor and a tertiary amine compound, which is a metal foil. It is characterized by being applied on top.

In such a substrate for a printed circuit board according to the present invention, the tertiary amine compound is preferably a nitrogen-containing heterocyclic compound.

The present invention also includes a printed circuit board in which such a printed circuit board base material of the present invention is used.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The printed circuit board substrate of the present invention comprises:
The base resin composition containing a polyimide resin precursor and a tertiary amine compound is formed on a metal foil by coating.

The polyimide resin precursor used in the present invention is a precursor resin composition which can be converted into a polyimide resin by curing, and examples thereof include polyamic acid resin. The polyamic acid resin is not particularly limited, but usually has a repeating unit structure represented by the following general formula (1), and for example, its weight average molecular weight is 50
About 00 to 200,000, preferably 10,000 to 1
Approximately 00000 is included.

[0012]

[Chemical 1] (In the formula, R1 represents a tetravalent organic group and R2 represents a divalent organic group.) In the above formula (1), examples of the tetravalent organic group represented by R1 include benzene, naphthalene, and Perylene, diphenyl, diphenyl ether, diphenyl sulfone, diphenylpropane, diphenylhexafluoropropane,
Examples thereof include aromatic, araliphatic, aliphatic, and alicyclic tetravalent organic groups having a skeleton such as benzophenone, butane, and cyclobutane. Preferred are tetravalent organic groups having a skeleton of benzene, diphenyl, diphenylhexafluoropropane and benzophenone. In addition, these tetravalent organic groups may be only one kind, or may be two or more kinds.

Further, in the above formula (1), 2 represented by R2
Examples of the valent organic group include a skeleton such as diphenyl ether, benzophenone, diphenylmethane, diphenylpropane, diphenylhexafluoropropane, diphenyl sulfoxide, diphenyl sulfone, diphenyl, benzene, and diphenoxybenzene, aromatic, araliphatic, and aliphatic. And divalent organic groups of group and alicyclic. Preferably, diphenyl ether, benzene,
A divalent organic group having a skeleton of diphenoxybenzene can be mentioned. Note that these divalent organic groups may be only one type, or may be two or more types.

More specifically, such a polyamic acid resin can be obtained by reacting an organic tetracarboxylic dianhydride with a diamine. Examples of the organic tetracarboxylic dianhydride include pyromellitic dianhydride, 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride, and 2,2-bis (2,3-dicarboxyphenyl). ) -1,1,1,3,3,3-hexafluoropropane dianhydride, 2,2-bis (3,4-dicarboxyphenyl) -1,1,1,3,3,3-hexafluoro Propane dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic acid dianhydride, bis (3,4-dicarboxyphenyl) ether dianhydride, bis (3,4-dicarboxyphenyl) sulfonic acid Examples thereof include dianhydride. Further, they may be used alone or in combination of two or more kinds.

As the diamine, for example, m-phenylenediamine, p-phenylenediamine, 3,4 '
-Diaminodiphenyl ether, 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenyl sulfone, 3,3'-diaminodiphenyl sulfone, 2,2
-Bis (4-aminophenoxyphenyl) propane,
2,2-bis (4-aminophenoxyphenyl) hexafluoropropane, 1,3-bis (4-aminophenoxy) benzene, 1,4-bis (4-aminophenoxy)
Benzene, 2,4-diaminotoluene, 2,6-diaminotoluene, diaminodiphenylmethane, 4,4'-diamino-2,2-dimethylbiphenyl, 2,2-bis (trifluoromethyl) -4,4'-diamino Biphenyl etc. are mentioned. Further, they may be used alone or in combination of two or more kinds.

Of these organic tetracarboxylic dianhydrides, pyromellitic dianhydride, 3,
3 ', 4,4'-biphenyltetracarboxylic dianhydride,
2,2-bis (3,4-dicarboxyphenyl) -1,
1,1,3,3,3-hexafluoropropane dianhydride can be mentioned. Among these diamines, p-phenylenediamine and 4,4′-diaminodiphenyl ether are preferable.

In the polyamic acid resin, the organic tetracarboxylic dianhydride and the diamine are mixed in a suitable organic solvent such as N-methyl-2-pyrrolidone at a ratio such that they are substantially equimolar. , N, N-dimethylacetamide, N, N-dimethylformamide, dimethylsulfoxide, hexamethylphosphoramide, etc. are usually reacted at 0 to 90 ° C. for 1 to 48 hours to obtain a polyamic acid resin. It may be obtained as a solution of.

The tertiary amine compound used in the present invention is not particularly limited, and examples thereof include an aliphatic tertiary amine compound and a nitrogen-containing heterocyclic compound. Examples of the aliphatic tertiary amine compound include high-boiling tertiary amines such as tribenzylamine. Also,
Examples of the nitrogen-containing heterocyclic compound include non-covalent nitrogen-based compounds such as imidazoles, benzimidazoles, purines, pyridines, pyridazines, pyrimidines, pyrazines, triazines, quinolines, isoquinolines, and acridines. Those having an electron pair are mentioned.
These tertiary amine compounds may be used alone or in combination of two or more.

More specifically, for example, as imidazoles, for example, imidazole, N-methylimidazole, 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-phenylimidazole, 1-benzyl-2- Methyl imidazole, 2-phenyl-4-methyl imidazole, 1-aminoethyl-2-methyl imidazole, 2-phenyl-4-methyl-5-hydroxymethyl imidazole and the like can be mentioned.

Examples of pyridines include pyridine, methylpyridine, dimethylpyridine, propylpyridine, aminopyridine, p-dimethylaminopyridine, N, N-dimethylaminopyridine and the like.

Of these tertiary amine compounds, nitrogen-containing heterocyclic compounds are preferable, and imidazoles are more preferable.

The tertiary amine compound is usually added in an amount of 0.5 to 15 parts by weight, preferably 1 to 10 parts by weight, based on 100 parts by weight of the polyimide resin precursor. If the blending amount is less than this, warping or dimensional change may not be effectively prevented, while if the blending amount is more than this, the heat resistance and the like of the polyimide resin may decrease.

Then, the resin composition for a base material of the present invention is prepared by preparing the polyimide resin precursor as a solution of the polyamic acid resin, for example, as described above, and then blending the tertiary amine compound in the above ratio. Then by mixing,
It can be prepared.

Further, such a resin composition for a base material of the present invention is blended with a photosensitizer such as a 1,4-dihydropyrazine derivative to prepare a photosensitive resin composition for a base material. You may. If prepared as a photosensitive resin composition for a substrate, it can be formed into a predetermined pattern by exposure and development. The photosensitizer is usually 0.1 to 0.1 mol per 1 mol of the polyimide resin precursor.
It is preferable to mix it in the range of 1.0 mol. Further, for example, a photosensitive resin composition for a base material can be prepared by introducing a functional group having photosensitivity into the skeleton of the polyamic acid resin.

Further, such a resin composition for a base material of the present invention may be blended with an epoxy resin, bisallyl nadimide, maleimide or the like, if necessary.

The printed circuit board base material of the present invention is
The resin composition for a base material thus prepared can be formed by applying it on a metal foil by a known method.

The metal foil is a wiring material for a wiring circuit board, and examples thereof include a foil of a metal such as copper, nickel, aluminum, copper-beryllium, phosphor bronze, or an alloy thereof. Further, the surface of the metal foil may be coated with electroless nickel plating, an organic anticorrosion film, an inorganic anticorrosion film, or the like.

Next, referring to FIG. 1, a method for producing a two-layer base material, which is one embodiment of the base material for a printed circuit board of the present invention, will be described.
This will be described more specifically.

To prepare the two-layer substrate, first, referring to FIG.
As shown in (a), a metal foil 1 is prepared. The metal foil described above is used as the metal foil 1. Also, metal foil 1
Has a thickness of usually 5 to 100 μm, further 10 to 5 μm.
It is preferably 0 μm.

Then, as shown in FIG. 1 (b), after applying the resin composition for a base material of the present invention onto the metal foil 1,
The film 2 is formed by drying. The formation of the coating film 2 is carried out, for example, by preparing a solution of a resin composition for a base material such as a solution of a polyamic acid resin containing a tertiary amine compound, as described above, and using the solution with a known spin coater, bar coater or the like. Method and then 50
It may be dried by heating at ~ 120 ° C by hot air drying or the like. The thickness of the film 2 after drying is 3 to 100.
μm, and more preferably 5 to 50 μm.

Then, as shown in FIG. 1 (c), the film 2 that has been heated and dried is cured (imidized),
A two-layer substrate 4 is obtained in which a base insulating film 3 made of a cured product of a resin composition for a substrate is directly formed on the metal foil 1. Film 2
The curing may be performed by a known method, for example, 300 ° C to 50 ° C.
It may be heated at 0 ° C. As a result, the polyimide resin precursor is imidized to form the base insulating film 3 mainly made of polyimide resin, whereby the two-layer base material 4 can be obtained.

When the resin composition for a base material of the present invention is prepared as a photosensitive resin composition for a base material as described above, after the film 2 shown in FIG. After irradiating with actinic rays through a mask, a latent image is formed by heating if necessary, and by developing this, the film 2 can be formed into a predetermined pattern. It is possible to obtain the two-layer base material 4 in which the insulating base film 3 formed in the above pattern is directly formed on the metal foil 1.

The wiring circuit board of the present invention uses the wiring circuit board substrate thus formed.

That is, in order to manufacture a printed circuit board using the printed circuit board base material of the present invention, for example, a metal foil may be formed into a predetermined printed circuit pattern by a known patterning method. .

FIG. 1 shows a method for manufacturing an embodiment of a printed circuit board using the two-layer base material, following the production of the above-mentioned two-layer base material.

That is, in order to manufacture the printed circuit board 6, first, as shown in FIG. 1D, the metal foil 1 of the two-layer base material 4 obtained as described above is put into a predetermined wired circuit. After forming into a pattern, then, as shown in FIG.
The cover insulating film 5 may be coated on the metal foil 1 formed in the predetermined wiring circuit pattern. Note that FIG.
(D) and (e) are shown with the vertical direction reversed from that of FIGS. 1 (a) to 1 (c).

To form the metal foil 1 into a predetermined wiring circuit pattern, a known patterning method such as a subtractive method may be used. For example, in order to form a predetermined wiring circuit pattern by the subtractive method, first, as shown in FIG. 2A, a photoresist 7 is laminated on the metal foil 1. The photoresist 7 may be laminated by, for example, laminating a dry film resist by a known method. Next, as shown in FIG. 2B, the photoresist 7 is exposed through a photomask 8 corresponding to a predetermined pattern, and then the photoresist 7 is developed as shown in FIG. 2C. . Exposure and development of the photoresist 7 may be performed by a known method, and the photoresist 7 is developed into a predetermined resist pattern due to the difference in solubility of the developing solution between the exposed portion and the unexposed portion.

Then, as shown in FIG. 2D, the metal foil 1 is etched. The metal foil 1 may be etched by wet etching using an etching solution, and examples of the etching solution include cupric chloride solution, ferric chloride solution, ammonium persulfate solution, and ammonia-based alkaline solution. After that, as shown in FIG. 2E, the metal foil 1 can be formed as a predetermined wiring circuit pattern by removing the photoresist 7 by a known method.

Even when the metal foil 1 is thus etched to form a predetermined circuit wiring pattern, in the two-layer base material 4, the base resin composition for forming the base insulating film 3 is added to the tertiary amine. Since the compound is blended, it is possible to effectively prevent warpage and dimensional change after the formation of the wiring circuit pattern.

In forming such a wiring circuit pattern, electrolytic plating, electroless plating or the like is performed on the metal foil 1 formed as a predetermined wiring circuit pattern.
For example, a metal thin film of copper, chromium, nickel, gold, solder or the like may be formed.

The cover insulating film 5 shown in FIG. 1 (e) is, for example, the metal foil 1 formed in a predetermined wiring circuit pattern using the resin composition for a base material of the present invention in the same manner as above. It can be formed by applying, drying and curing on the above. The cover insulating film 5 is
Even without using the resin composition for a substrate of the present invention, for example, a resin film made of a polyimide resin or the like prepared in advance,
It may be formed by adhering it via an adhesive. The insulating cover film 5 thus formed usually has a thickness of 5 to 50 μm, preferably 10 to 30 μm.

In the printed circuit board 6 thus manufactured, the cover insulating film 5 is usually provided at a predetermined position.
For example, a via hole for terminal connection is formed by a known method such as drilling, laser processing, and etching, and a connection terminal is formed in the via hole by solder bump or gold plating.

Also in the formation of the insulating cover film 5, if the resin composition for a base material of the present invention is prepared as a photosensitive resin composition for a base material, after the film is formed in the same manner as described above, By exposing and developing, the cover insulating film 5 having a predetermined pattern can be formed. For example, a via hole for a connection terminal can be formed at the same time when the cover insulating film 5 is formed.

When a wired circuit board is manufactured using such a wired circuit board base material of the present invention, the metal foil of the wired circuit board base material is patterned into a predetermined wired circuit pattern. Also, it is possible to effectively prevent warpage and dimensional change, and moreover, the number of manufacturing steps thereof is the same as the conventional one, and efficient production can be realized. Therefore, a printed circuit board having good dimensional stability can be provided with high production efficiency.

The wiring circuit board of the present invention is not particularly limited, but is preferably effective as a wiring circuit board used in electric equipment and electronic equipment such as flexible wiring circuit boards and suspension boards with circuits. Used for.

The printed circuit board of the present invention is not limited to the embodiment shown in FIG. 1 as long as the base material for a printed circuit board of the present invention is used, and may be, for example, a multilayer printed circuit board. Good.

[0047]

EXAMPLES The present invention will be described in more detail below with reference to Examples and Comparative Examples, but the present invention is not limited to the Examples and Comparative Examples.

Preparation of Resin Composition for Base Material 0.15 mol of 4,4′-diaminodiphenyl ether and p-based on 1 mol of 3,3 ′, 4,4′-biphenyltetracarboxylic dianhydride. A solution of polyamic acid resin having a polyamic acid resin concentration of 15% by weight was prepared by reacting 0.85 mol of phenylenediamine in 2358 g of N-methyl-2-pyrrolidone.

Resin compositions A to D for base materials were prepared by adding the tertiary amine compounds shown in Table 1 to the solution of the polyamic acid resin at the ratios shown in Table 1.

Preparation of two-layer base material The resin compositions A to D for base materials were respectively applied onto the matte surface (roughened surface) of a rolled copper foil having a thickness of 18 μm, and the temperature was adjusted to 2
Dry for 0 minutes. It is then placed under vacuum (5-100
Pa) and curing (imidization) at 400 ° C. to produce two-layer base materials of Examples 1 to 3 and Comparative Example 1, respectively. The thickness of the obtained polyimide resin layer of each two-layer substrate was 12.5 μm.

Evaluation of Warp Amount After completely removing the copper foil of the two-layer base material of Examples 1 to 3 and Comparative Example 1 with an aqueous solution of ferric chloride, a test piece of 1 cm × 2 cm was prepared and warped. The quantity was measured. The results are also shown in Table 1. In addition, the warp amount is obtained by installing a test piece on a horizontal plate as schematically shown in FIG. 3 and measuring the distance from the front surface of the horizontal plate to the edge portion of the back surface of the test piece in the width direction of 2 cm. It was determined by measuring.

Evaluation of Dimensional Change Rate From the two-layer base materials of Examples 1 to 3 and Comparative Example 1, 100c
A test piece of m × 100 cm was prepared, and then the copper foil of this test piece was treated with an aqueous solution of ferric chloride to obtain a line width of 100
It was formed in a pattern of 100 μm and a line interval of 100 μm.
Then, as schematically shown in FIG. 4, the dimensional change rate of the length of one side in the width direction of the pattern (the direction orthogonal to the line) before and after the formation of the pattern (length before pattern formation / after pattern formation) Was measured. The results are also shown in Table 1.

[0053]

[Table 1] As is clear from Table 1, the two-layer base materials of Examples 1 to 3 to which the tertiary amine compound was added were compared with the two-layer base material of Comparative Example 1 to which the tertiary amine compound was not added. It can be seen that both the warp amount and the dimensional change rate are remarkably small.

[0054]

EFFECT OF THE INVENTION By using the substrate for a printed circuit board of the present invention,
When a printed circuit board is manufactured, even if the metal foil of the printed circuit board base material is patterned into a predetermined wired circuit pattern, it is possible to effectively prevent warpage and dimensional change from occurring. The number of manufacturing steps is the same as before,
It is possible to realize efficient production. Therefore, a printed circuit board having good dimensional stability can be provided with high production efficiency.

[Brief description of drawings]

FIG. 1 is a process chart of one embodiment showing a method for producing a two-layer substrate using the resin composition for a substrate of the present invention and then producing a wired circuit board using the two-layer substrate. And
(A) is a step of preparing a metal foil, (b) is a step of applying a resin composition for a substrate on the metal foil and then drying it to form a film, and (c) is a film. Forming an insulating base film by curing the resin, (d)
Shows a step of forming a metal foil in a predetermined wiring circuit pattern, and (e) shows a step of covering the metal foil formed in the predetermined wiring circuit pattern with a cover insulating film.

FIG. 2 is a process chart showing details of a process of forming the metal foil of FIG. 1 (d) into a predetermined wiring circuit pattern, FIG.
Is a step of laminating a photoresist on the metal foil, (b)
Is a step of exposing the photoresist through a photomask, (c) is a step of developing the photoresist,
(D) shows a step of etching the metal foil, and (e) shows a step of removing the photoresist.

FIG. 3 is a schematic explanatory diagram for explaining a method of measuring a warp amount in an example.

FIG. 4 is a schematic explanatory diagram for explaining a method of measuring a dimensional change rate in an example.

[Explanation of symbols]

1 metal foil 2 film 3 Base insulation film 4 two-layer base material 6 wired circuit board

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08G 73/10 C08G 73/10 C09D 179/08 C09D 179/08 A F term (reference) 4F100 AB01A AB17 AB33A AH03B AH07B AK49B AL05B BA02 BA07 GB43 JL02 JL04 4J038 DJ031 JB01 JB25 JB26 JB31 PB09 PC02 4J043 PA02 PC065 QB31 QC04 SA32 ZA41 ZB50

Claims (3)

[Claims] 1. A substrate for a printed circuit board, characterized in that a resin composition for a substrate containing a polyimide resin precursor and a tertiary amine compound is applied onto a metal foil. 2. The substrate for a printed circuit board according to claim 1, wherein the tertiary amine compound is a nitrogen-containing heterocyclic compound. 3. A wired circuit board, wherein the printed circuit board base material according to claim 1 is used.