JPH02204029A - Manufacture of substrate for printed circuit panel - Google Patents

Abstract

PURPOSE:To improve the peeling strength and the heat resistant by a method wherein a copper foil is bonded to a substrate by employing thermocuring film type adhesive agent consisting of the composition of polyimide, containing polymaleimide and molded by cast molding. CONSTITUTION:A copper foil is bonded to a substrate by employing thermocuring film type adhesive agent, consisting of the composition of polyimide, having a building block shown by a formula I (here; Ar shows the group of a formula II or a formula III), containing the group of the formula II and the group of the formula III in the molar ratio of the latter/the former of 0/100-90/10, mixed with 10-50 weight % of polymaleimide shown by a formula IV (here; (m) is an integer more than 2 and R is the group of valence of (m) having more than 2 of carbon number) and molded by cast molding. The mixing of polyimide and polymaleimide is effected by adding polyimide varnish produced by resolving polyimide by solvent such as cresol, phenol, dimethylformamide, toluene or the like with polymaleimide to resolve it.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for manufacturing a printed wiring board substrate.

[Conventional technology]

Conventionally, polyimides used in heat-resistant adhesives have mainly been precondensates of bismaleimide and 4,4'-diaminodiphenylmethane. Since this polyimide has poor storage stability in a solution state, it is handled in powder form, and when used in the manufacture of printed wiring board substrates, it is once dissolved in a solvent before use.

[Problem to be solved by the invention]

However, this polyimide itself was hard and brittle and could not be cast into a film.

On the other hand, thermoplastic polyimides such as polyetherimide are known, but these have the disadvantage that they do not harden and are deformed by heat even once molded.

Therefore, it has been difficult or inappropriate to use film-like polyimide adhesives for manufacturing substrates for printed wiring boards.

[Means to solve the problem]

The present invention has a structural unit represented by the general formula [wherein Ar represents a group of formula (a)], and the group of formula (a) and the group of formula (b) are combined in the latter/former. Molar ratio O/100~
Polyimide (A) containing in a ratio of 90/10 and polymaleimide (B) represented by the general formula (wherein 1 formula, 5m is an integer of 2 or more, and R is an m-valent group having 2 or more carbon atoms) Polymaleimide (B) is 1 to polyimide (A).
A method for manufacturing a substrate for a printed wiring board, characterized in that a substrate and a copper foil are bonded using a thermosetting film adhesive obtained by casting a composition containing 0 to 50% by weight. Regarding.

In the present invention, polyimide (A) is cresol.

3.3', 4゜4 in a solvent such as phenol or toluene
'-benzophenonetetracarboxylic dianhydride (hereinafter referred to as B
(abbreviated as TDA) and bis(4-(3-aminophenoxy)
Phenyl) sulfone (hereinafter abbreviated as m-APPS) can be obtained by heating and stirring, but the corresponding polyamic acid can be synthesized by reacting it in an aprotic polar solvent such as dimethylacetamide or dimethylformamide at a temperature below room temperature. It can also be obtained by dehydration and ring closure using a dehydrating agent such as acetic anhydride-pyridine.

In the above, as the diamine, in addition to m-APPS, 2,4-diaminotoluene (hereinafter referred to as 2゜4-1
) AT) can be used together.

m-APPS and 2,4-DAT in polyimide (A)
is the molar ratio of 2.4-DAT/m-APPS is 0/10
It is preferable to contain 2.4-DAT in a ratio of 0 to 90/10.If 2.4-DAT is more than 90 mol%, not only will the polyimide (A) become hard and the moldability of the composition will deteriorate; Film adhesive has poor flexibility.

Specific examples of the polymaleimide CB) that can be used in the present invention include N,N'-(4,4'-diphenylmethane)bismaleimide, N,N'(4,4'-diphenyloxy)bismaleimide, N, N'-p-phenylene bismaleimide, N.

N'-m-phenylene bismaleimide, N, N'-2,
4-)-Rylene bismaleimide, N,N'2.6-Drylene bismaleimide, N,N'-ethylene bismaleimide, N,N'-hexamethylene bismaleimide, etc. There are polymaleimides, and these can be used alone or in combination of two or more.

The mixing ratio of polyimide (A) and polymaleimide (B) is 1 part polymaleimide (B) to polyimide (A).
It is preferably selected within the range of 0 to 50% by weight. If the amount of polymaleimide CB) is less than 10% by weight, curing will not be sufficient, and if it is more than 50% by weight, not only the moldability of the composition will be poor, but also the flexibility of the film adhesive will be poor.

Polyimide (A) and polymaleimide (B) may be mixed in powder form, but usually polyimide (A') is dissolved in a solvent such as L-nosol, phenol, dimethylformamide, toluene, etc. to form a polyimide varnish. This is carried out by adding and dissolving the polymaleimide (B).

The composition thus obtained can be cast on a glass plate, a stainless steel plate, etc. and dried to produce a film-like adhesive that does not contain a base material, which can also be used for various purposes. In this case, the drying temperature and time vary depending on the solvent used and the type of polymaleimide (B), but it is necessary to keep the temperature lower than the temperature at which polymerization of the polymaleimide (B) becomes noticeable, and for 3 hours the amount of residual solvent is approximately It must be kept below 1%.

A substrate for a printed wiring board can be obtained by sandwiching the film-like adhesive described above between a base material such as an aluminum plate or a polyimide film and copper foil and heating and pressurizing the adhesive. The heating temperature at this time is preferably a temperature equal to or higher than the softening point of the film adhesive to cause the film adhesive to undergo a curing reaction.

〔Example〕

Hereinafter, the present invention will be explained in detail with reference to Examples, but the scope of the present invention is not limited to these Examples.

Example I BTDA32.2g, m-APP521.6g.

2. 6.1 g of 4-DAT was placed in a four-bottle flask equipped with a stirrer, a thermometer, a nitrogen gas introduction tube, and a cooling tube, and 539 g of m-cresol and 108 g of toluene were added, and the mixture was heated and stirred while flowing nitrogen gas. . 16 at 150-160℃
After reacting for hours, the resin content was 17.111%.

A polyimide varnish with a viscosity of 15P was obtained. 3.56 g of N,N'-(4,4'diphenylmethane) bismaleimide was dissolved in 100 g of this polyimide varnish to obtain a resin composition. This resin composition did not gel even after being stored at room temperature for one month. This resin composition was cast onto a glass plate and dried at 160°C for 30 minutes, resulting in a thickness of 25 μm.
A flexible uncured film was obtained. This film is 25
A strong cured film was obtained by heating at 0° C. for 30 minutes. This cured film did not melt even when placed in a solder bath at 300°C.

The resin composition (varnish) was cast onto a glass plate,
It was dried at 0° C. for 30 minutes to obtain a film adhesive having a thickness of 25 μm. Apply this film adhesive to a 1m thick aluminum plate and
50kgf/d, 250 between 5μm thick R foil
A laminate was obtained by pressing at a temperature of 30 minutes. The copper foil peeling strength is 2.5kg f/dll and 30
Even when immersed in solder at 0°C for 60 seconds, no blistering or peeling occurred.

Examples 2-4 and Comparative Examples 1-2 BTDA32.2g, m-APP821.6g.

2.4-Pour 6.1 g of DAT into a four-loaf flask equipped with a stirrer, thermometer, nitrogen gas introduction tube, and cooling tube, and m-
Added 539g of cresol and 108g of toluene,
The mixture was heated and stirred while flowing nitrogen gas.

Reacted at 150-160℃ for 16 hours, resin content 17.8
% and a viscosity of 15P was obtained. This polyimide varnish was poured into acetone, reprecipitated, ground, washed, and dried to obtain polyimide powder. The reduced viscosity of polyimide powder [concentration 0.1 g/dQ, solvent N, N-dimethylformamide (DMF), temperature 30.0°C] is 0
．． It was 72 dQ/g. Obtained polyimide powder 10
0g and N,N'-(4,4'-diphenylmethane)
A varnish was obtained by dissolving bismaleimide (BMI) Log in 400 g of DMF. This varnish was cast onto a glass plate, dried at 130℃ for 10 minutes, peeled off, and fixed on an iron frame for 200℃.
C. for 1 hour to obtain a film adhesive (used in Example 2). The resulting film adhesive has a thickness of 25μ
It had a softening point of 230° C., residual solvent concentration of 1%, and excellent flexibility without cracking even when bent to 180°.

In addition, a film adhesive was obtained in the same manner as above except that the BMI amount was changed as shown in Table 1.

Table 1 shows the softening points of these film adhesives.

These film adhesives were bonded to a 1°C thick aluminum plate and 35μ
50kgf/J, 2 between m-thick single-sided roughened copper foils
Lamination was performed at 75° C. for 30 minutes to obtain a copper-clad substrate. Table 1 shows the characteristics of each substrate.

Table 1 BMI amount indicates the weight part (phr) of BMI used relative to 100 weight parts of polyimide.

Softening point is load 25kgf/cd, heating rate 10℃/Otori 1
It was measured by the penetration method at n.

The steel foil peel strength was measured as 90' peel strength at a tensile rate of 50 W/gin.

Soldering heat resistance was evaluated by floating a 2011 Il square test piece on a solder bath with the copper foil facing down, observing the presence or absence of blistering, and rating it as O if there was no blistering.

Example 5 A sheet of the same film adhesive as used in Example 2 above was sandwiched between a 50 μm thick polyimide film and a 35 μm thick single-sided roughened f14fti, and the film was heated to 275'C, 50k.
Lamination was performed under the condition of gf/J for 30 minutes to obtain a substrate for a flexible printed wiring board. The 90° copper foil peel strength of this board was measured at a tensile speed of 50 m/win, and it was 2 at room temperature.
, 8 kg f/cs, 2.4 kg at 150°C
It was f/am. Further, this board was immersed in a 300° C. solder bath for 1 minute, but no blistering occurred.

Example 6 A film adhesive was produced in the same manner as in Example 2 except that BMI jl was 30 phr. This film adhesive and 3
Layer 5 μm single-sided roughened copper foil and heat at 275°C.

Lamination was performed under the conditions of 50 kgf/ej and 30 minutes to obtain a substrate for a flexible printed wiring board.

The 90゜ copper foil peel strength of this board is 2.5 kg at room temperature.
f/as, 2,3 kg f/C at 150℃
I, and no blistering occurred even after being immersed in a 300°C solder bath for 1 minute.

Example 7 A flexible printed wiring board was prepared in the same manner as in Example 5 using a film adhesive prepared in the same manner as in Example 2 except that 15 g of BMI-M (polymaleimide manufactured by Mitsui Toatsu Chemical Co., Ltd.) was used instead of BMH. A substrate for use was obtained. 90' of this board
Copper foil peel strength is 2.5 kgf/cs at room temperature, 15
2,1 kg f/am at 0°C and 300°C
No blistering occurred even after immersion in the solder bath for 1 minute.

Comparative Example 3 Using Vyralux (acrylic film adhesive manufactured by DuPont) instead of the film adhesive, lamination was performed under the same conditions as in Example 5 at 180°C, 30 kgf/aJ, and 60 minutes to create a flexible A substrate for printed wiring board was obtained. The 90° copper foil peel strength of this board is 2. ．． 2kgf
/am, 0 at 150℃, 6 kg f/cxa
Met. Further, when this board was immersed in a 300° C. solder bath for 1 minute, blistering occurred.

Reference Example I BMI-M (Mitsui Toatsu Chemical Co., Ltd.) instead of N,N'-(4,4'-diphenylmethane)bismaleimide!
A film adhesive was obtained in the same manner as in Example 2, except that 20 g of 1-polymaleimide was added. The obtained film adhesive had a thickness of 25 μm.

Amount of remaining solvent 1. It had a softening point of 235° C. and did not crack even when bent to 18° and had excellent flexibility.

Comparative Reference Example 1 A varnish prepared by dissolving 100 g of Kelimide 601 (Nippon Polyimide Co., Ltd. I! polyamino bismaleimide resin) in DMFLoog was cast on a glass plate at 130°C for 10 minutes.
It was then dried at 170°C for 20 minutes, but it was too brittle to form a film.

〔Effect of the invention〕

The printed wiring board substrate obtained by the present invention is as follows.

Claims (1)

[Claims] 1. General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ [However, in the formula, Ar is formula (a) ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (a) or formula (b) ▲ Numerical formulas, chemical formulas, tables, etc. has a structural unit represented by ▼ (b) represents a group, and the group of formula (a) and the group of formula (b) are combined in a molar ratio of 0/100 to 0/100 to the former.
Polyimide (A) containing at a ratio of 90/10 and general formula ▲ Numerical formula, chemical formula, table, etc. ▼ (However, in the formula, m is an integer of 2 or more, and R is an m-valent group having 2 or more carbon atoms. Polymaleimide (B) represented by
Production of a substrate for a printed wiring board, characterized in that a base material and a copper foil are bonded using a thermosetting film adhesive formed by casting a composition containing 0 to 50% by weight. Law.