JPH01160089A - Adhesive for wiring board - Google Patents

Abstract

PURPOSE:To obtain an adhesive for multi-wire wiring board which is superb in insulation reliability at high temperature to be obtained by composing it of a specific epoxy resin, polyvinyl butyral resin, cross-linking agent. CONSTITUTION:An adhesive is formed by mixing an epoxy resin, polyvinyl butyral resin and cross-linking agent in an organic solvent: an epoxy resin where the ratio of epoxy resin with a molecular weight of 5000 or more to one with a molecular weight which is less than 5000 is from 10:90 to 90:10 and a polyvinyl butyral resin having pts.wt. of 3-30 with respect to 100 pts.wt. of the epoxy resin. By using an insulation electric wire for the surface of insulation substrate to be fixed, wire can be laid even by reducing stylus pressure applied on laying wire and also the adhesive is flexible and can absorb supersonic energy during laying of wire.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an adhesive for a wiring board (hereinafter referred to as a multi-wire wiring board) using insulated wires in a necessary wiring pattern.

(Conventional technology) Multi-wire wiring boards are produced by forming an adhesive coating on an insulating substrate with an inner layer circuit formed thereon by laminating or coating it, and then running insulated wires using a numerically controlled wiring machine and simultaneously heating and melting it using ultrasonic vibrations. After gluing (hereinafter referred to as wiring) by
It is manufactured by laminating prepreg to fix an insulated wire, drilling a through hole across the wire, and forming an electroless plated metal layer on the inner wall of the hole.

Since this multi-wire wiring board uses insulated wires, the wires can cross each other on the same plane, and the wiring capacity per layer is about twice that of a general printed wiring board.

In addition, since the insulated wires are installed directly on the board, artwork unlike general printed wiring boards is not required, and design changes are easy.

The conventional insulated wire used for this has a diameter of 0.10 to 0.1
It has a double structure in which a 6 mm copper wire is coated with polyimide resin, and then a nylon resin is applied as an adhesive layer to increase the adhesive strength of the wire. The adhesive coating needs to be an insulated wire or a wire, be easily fixed, and have heat resistance and insulation properties. For this reason, adhesives are made of natural rubber or synthetic rubber with excellent adhesive properties as the main component, cross-linked with alkylphenol resin to improve heat resistance and insulation, and further mixed with epoxy resin and various fillers as appropriate. The use of agents was recommended in Japanese Patent Publication No. 45-21434 and Special Publication No. 1973-
Known by 2063.

(Problems to be Solved by the Invention) In recent years, in order to apply multi-wire wiring boards to electronic devices that have become increasingly dense, it has become necessary to perform wiring at a higher density than before. That is, the wiring density of the conventional multi-wire wiring board was three wires between through holes spaced at 2.degree. 54 mm intervals, but in the future, a wiring density of five or more wires will be required. For this reason, the conductor diameter of insulated wires has traditionally been 0.
．． lO ~ 0.16mm, now 0.08mm
Must be as follows. However, if a double-structure insulated wire is used as is, in which the conventional copper wire is coated with polyimide resin and then coated with nylon resin as an adhesive layer to increase the adhesive strength of the wiring, proper adhesion will occur during wiring. A problem has arisen in which the conductors of the insulated wires break at the points where the wires intersect due to the stylus pressure and ultrasonic energy applied to obtain power.

In order to prevent such disconnection, it is conceivable to change the conductor of the insulated wire to a metal with high breaking strength. Therefore,
When Ag/Cu, Sn/Cu, Mn/Cu, etc. are used,
Although the problem of disconnection can be solved, these alloys have low conductivity (the longer the wiring, the higher the conductor resistance and the voltage drop in the circuit, making them impractical. Compared to this, the resistance value is large and the noise margin decreases due to voltage drop, making it impractical.

It is also possible to improve the wiring mechanism of the wiring machine in order to reduce the load applied to the insulated wire, but in reality, it is possible to maintain the wiring ability and reduce the load applied to the insulated wire. There are limits to how to reduce it, and it is difficult.

Therefore, we considered making the coating layer of the wire thicker to increase the breaking strength and absorb ultrasonic energy.
When the thickness of the polyimide resin was increased to 3 to 4 times the conventional thickness, the probability of wire breakage was reduced, but although the cause is unknown, there were cases where no metal was formed in the metal layer on the inner wall of the through hole. This occurred frequently, and thermal shock tests revealed that the connection reliability in those areas was extremely reduced.

The present invention solves the above 9 or more drawbacks, maintains or exceeds the conventional electrical performance, and provides a high-density multi-wire wiring board with excellent insulation conductivity at high temperatures. It provides adhesives.

(Means for Solving Problems) The present invention provides a method for manufacturing a wiring board in which an adhesive coating is formed on an insulating substrate, and insulated wires are laid on the coating and simultaneously bonded to form a desired wiring pattern. The composition of the agent coating film is an epoxy resin with a molecular weight of 5000 or more and a molecular i500
The ratio of epoxy resin less than 0 is 10:90 to 90:10
Epoxy resins in the range of and the epoxy resin 100
The present invention relates to an adhesive for wiring boards, characterized in that it uses a composition comprising 3 to 30 parts by weight of polyvinyl butyral resin and a crosslinking agent.

Insulating substrates that can be used in the present invention include all insulating substrates that can be used in conventional multi-wire wiring boards, such as glass heavy industry] 1-Si resin epsilon laminate, glass cloth polyimide resin copper clad A power supply layer and a ground layer are formed on a laminate or the like by a known etching method, and a prepreg such as glass cloth epoxy resin or glass cloth polyimide resin is laminated thereon and cured by heating.

Among the components of the adhesive coating film according to the present invention, one of the epoxy resins having a molecular weight of 5000 or more is Epicoat 0L-53-L
-32,0L-53-BH-35 [molecular weight 55.000
), 0L-55-L-32, 1255-HX-30 [molecular weight 70.000 or more] (Yuka Shell Epoxy Co., Ltd., trade name).

Or Phenotote YP-40 [molecular weight 20゜000
), YP-50M (molecular weight 30.0001, YP-5
0 (molecular weight 40.000) (Tobu Kasei Co., Ltd., trade name), or PKHH, PAHJ [molecular weight 40.00
0) (Union Carbide Co., trade name) etc. can be used. Note that these polymeric epoxy resins are generally called phenoxy resins.

In addition, as an epoxy resin with a molecular weight of less than 5,000,
Epicote 828, 834, 871, 872.1001
, 1002.1003.1004.1007 (Yuka Shell Epoxy Co., Ltd., trade name), D, E, R, 317
,330,331,361,661,662,664,
667,732,736,D,E,N,431.438
, 439.485 (Dow Chemical Company, trade name).

In addition, brominated epoxy resins such as E, R, 511,542 (Dow Chemical Company, trade name).

It can also be used to impart flame retardancy.

As polyvinyl butyral resin, SRESOC BL-
1, BL-2, BL-3, BL-3, BX-L, BM-
1, BM-2, BM-5, 8M-3, BH-3, BX-
1, BX-7 (Sekisui Chemical Co., Ltd., trade name), Denka Butyral #20o-L, #30oo-1, #30o
o-2. #3000-4. #3000-, #4000
-1°#4000-2. #5000-A, #6000-
C (Denki Kagaku Kogyo Co., Ltd., trade name), etc.

As the crosslinking agent, a combination of pronochysocyanate-1 and an epoxy curing agent, or a combination of an alkylated melamine and an epoxy curing agent, etc. can be used. Among these, the blocked isocyanate in the former combination is Corone 1. -2503.2507.2515. Coronate AP Stable, Millionate MS-50 (Japan Polyurethane Industry Co., Ltd., trade name), Fleran U1. U
T.

Death module AP stable, CT stable, BL
Iloo, BL1265. There are BL3175 (trade name, manufactured by Sumitomo Bayer Urethane Co., Ltd.), and as the epoxy curing agent, acid anhydrides, dicyandiamide, etc. can be used.

In addition, as the alkylated melamine in the latter combination, methylated melamine resin Melan 520.521
．． 522.523 (Hitachi Chemical Co., Ltd., product name)
Alternatively, Melan 20. of butylated melamine resin. 22
．． 23. 25. 26. X65, X66 (Hitachi Chemical Co., Ltd., trade name), etc. can be used, and the epoxy curing agent in this case is preferably a mixture of an imidazole derivative and an acidic organic compound.
2PZ-CNS [1-cyanosupra-2-phenylimidazole trimellitate), 2E4MZ-CNS
[1-cyanoethyl-2-ethyl-4-methylimidazole trimellitate] (Shikoku Kasei Kogyo Co., Ltd., trade name) and the like.

In the present invention, these compositions are prepared by mixing 1 epoxy resin with a molecular weight of less than 5000 and 10 epoxy resin with a molecular weight of 500 or more.
:90 to 90:10 mixed epoxy resin and 3 to 30 parts by weight per 1°O by weight of the epoxy resin.
The polyvinyl butyral resin is further mixed with a crosslinking agent in an organic solvent to form an adhesive. In addition, fillers such as mica, finely powdered silica, zirconium silicate, magnesium silicate, and white titanium, which are effective in adjusting the flow characteristics of the adhesive, are added as appropriate.

Additionally, an electroless plating catalyst is added to improve the adhesion of the plating to the inner walls of the through holes, etc. The organic solvent used is selected from methyl ethyl ketone, acetone, +-luene, xylene, methyl isobutyl ketone, ethyl acetate, methyl cellosolve, cello acetate, dimethyl formamide, etc., or a combination thereof.

(Function) The adhesive film formed on the surface of the insulating substrate on which the insulated wires are fixed contains polyvinyl butyral resin with high adhesive strength, so wiring can be done even if the stylus pressure applied during wiring is reduced. be. Furthermore, this adhesive has a molecular weight of 50
Since the epoxy resin of less than 0.00 is used, it is flexible and can absorb ultrasonic energy during wiring.

In addition, since this adhesive uses an epoxy resin with a molecular weight of 5000 or less, the flexibility previously obtained with organic solvents can be obtained with a reduced amount of organic solvent, reducing the volatilization of the solvent during wiring. It is possible to reduce and constantly absorb stylus pressure and ultrasonic energy during wiring.

(Example 1) 1) A varnish with the composition shown below was prepared and applied to a PET film (trade name, Higashi Shichiguchi Kagaku Co., Ltd.), which is a transfer base material, so that the film thickness after drying was 150 μm. , 120℃
This was dried for 15 minutes to create an adhesive sheet.

Composition of insulating varnish: Internal molecular weight of 100 parts by weight of epoxy resin: 5000 or more; 40 parts by weight of PKHH (Union Carbide Co., Ltd., trade name) Molecular weight less than 5,000; - 50 parts by weight of Epicoat 1001 (trade name, Yuka Shell Epoxy Co., Ltd.) 10 parts by weight of DEN43B (Dow Chemical Company, trade name).

Polyvinyl butyral resin; Eslesoku BX-1 (Sekisui Chemical Co., Ltd., trade name)
15 parts by weight of crosslinking agent; 1 to 20 parts by weight of Desmodur BL1265 (Sumitomo Bayer Urethane Co., Ltd., trade name); 3 parts of dicyandiamide (trade name, Wako Pure Chemical Industries, Ltd.)
Filler by weight: Crystallite VX-X (Tatsumori Co., Ltd.)

20 parts by weight of plating catalyst (trade name); 3 parts by weight of Cat #10 (trade name, Hitachi Chemical Co., Ltd.).

Organic solvent: Mix in 150 parts by weight of cellosolve acetate (Wako Pure Chemical Industries, Ltd., trade name).

2) Trainise # to electrical annealed copper wire with a diameter of φ0.08mm
2000 (trade name, Toshi Co., Ltd.) was coated to a thickness of about 10 μm at a furnace length of 3 m, a furnace temperature of 300 cm, a baking speed of 20 m/min, and 11 baking times.

3) Glass cloth epoxy copper clad laminate MCL-E-168 (
The inner layer circuit is formed by etching the prepreg GEA-168N (Hitachi Chemical Co., Ltd., trade name) of glass fabric epoxy resin containing a plating catalyst.
(product name) is layered and heated and pressed to form an insulating substrate.

4) Attach the adhesive sheet created in (■) to the insulating substrate in 3).

5) Peel off the transfer PET film (Tohcello Chemical Co., Ltd., trade name) and wire the insulated wires of 2) on the insulating substrate using a wiring machine.

6) Glass fabric epoxy resin prepreg GEA-168
N (manufactured by Hitachi Chemical Co., Ltd., trade name) is superimposed on the component of 5) and laminated by heating and pressing.

7) Laminate HITARESOX S-500X-9 (Hitachi Chemical Co., Ltd., trade name), a polyethylene film with adhesive, as a plating mask to the composition of 6), and make holes where the through holes should be. Electroless copper plating solution Hid-410 (Hitachi Chemical Co., Ltd., trade name)
A copper layer of about 40 μm was formed on the inner wall of the hole.

8) The plating mask was peeled off to obtain a multi-wire wiring board.

(Example 2) ■) Create a glue varnish with the composition shown below, apply it to a PET film (trade name, Tohcello Chemical Co., Ltd.), which is a transfer material, so that the film thickness after drying is 150 μm, and
The adhesive sheet +- was prepared by drying at C for 15 minutes.

Composition of insulating varnish: Internal molecular weight of 100 parts by weight of epoxy resin: 5,000 or more; Pheno)-)YP-50 (Tobu Kasei Co., Ltd., trade name)
50 parts by weight molecular weight less than 5000; - 50 parts by weight of Epicoat 1001 (Yuka Ciel Evokin Co., Ltd., trade name) 2.

Polyvinyl butyral resin; Eslesoku BX-1 (Sekisui Chemical Co., Ltd., trade name)
10 parts by weight of crosslinking agent; 1 part of alkylated melamine, 2 parts of Melan 523 (Hitachi Chemical Co., Ltd., trade name)
0 parts by weight epoxy curing agent; 2PZ-CNS (Shikoku Kasei Kogyo Co., Ltd.)

3 parts by weight of product name) filler; Crystallite VX-X (Tatsumori Co., Ltd.)

20 parts by weight of plating catalyst (trade name); 3 parts by weight of Cat#]O (trade name, Hitachi Chemical Co., Ltd.).

Organic solvent: Mix in 150 parts by weight of cellosolve acetate (Wako Pure Chemical Industries, Ltd., trade name).

2) The following is the same as in Example 1.

(Example 3) 1) A varnish with the composition shown below was prepared and applied to a PET film (trade name, Tohcello Chemical Co., Ltd.), which is a transfer base material, so that the film thickness after drying was 150 μm. ℃
and dried for 15 minutes to create an adhesive sort.

Composition of insulating varnish: Internal molecular weight of 100 parts by weight of epoxy resin: 5,000 or more; Pheno)-)YP-50 (Tobu Kasei Co., Ltd., trade name)
70 parts by weight, 20 parts by weight of Epicote 828 (trade name, Yuka Shell Epoxy Co., Ltd., trade name) and 10 parts by weight of DEN438 (trade name, Dow Chemical Company), which has a molecular weight of less than 5,000.

Polyvinyl butyral resin; Eslesoku BM-2 (Sekisui Chemical Co., Ltd., trade name)
20 parts by weight of crosslinking agent; alkylated melamine; 20 parts by weight of Melan 523 (Hitachi Chemical Co., Ltd., trade name)
Part by weight Epoxy curing agent; 2PZ-CNS (Shikoku Kasei Kogyo Co., Ltd.)

2 parts by weight of product name) filler; Crystallite VX-X (Tatsumori Co., Ltd.)

Cat#10 (Hitachi Chemical Co., Ltd., trade name) 3 parts by weight of plating catalyst
Parts by weight.

Organic solvent: Mix in 200 parts by weight of cellosolve acetate (Wako Pure Chemical Industries, Ltd., trade name).

2) The following is the same as in Example 1.

This multi-wire wiring board has 350 wires in design, and the fabric density is 3 wires/2.54m in the orthogonal direction.
The length of the insulated wire is approximately 40,000 points/piece, and the length is 1/2°54mm in the 45 degree direction.

As a result of creating a multi-wire wiring board through this implementation, there were no disconnections or short circuits, and no abnormalities were observed even after 20 cycles of hot oil testing. In addition, the insulation resistance between the inner layer circuit board circuit and the through hole is 10 at room temperature.
L+Ω or more, and 101Ω or more at 120° C., indicating good insulation properties.

Furthermore, the effect of applying one coat is that the amount of organic solvent contained in the adhesive coating film is small, and there are few volatile components, so it is possible to provide a good environment for each worker, and the surface after application is sticky. It was easy to handle because there was no

(Effect of the invention) As explained above, the adhesive coating film has a molecular weight of 9 and 5000.
An epoxy resin in which the ratio of the above epoxy resin to an epoxy resin with a molecular weight of less than 5000 is in the range of 10:90 to 90=10, and 3 parts by weight for 100 parts by weight of the epoxy resin.
An adhesive made of 30 parts by weight of polyvinyl butyral resin and a crosslinking agent maintains or exceeds conventional electrical performance, has a low probability of 2wI line generation, and also improves connection reliability. Also can provide excellent multi-wire wiring board adhesive.

Claims (1)

[Claims] An epoxy resin in which the ratio of an epoxy resin with a molecular weight of 5,000 or more to an epoxy resin with a molecular weight of less than 5,000 is in the range of 10:90 to 90:10, and a polyvinyl butyral resin in an amount of 3 to 30 parts by weight per 100 parts by weight of the epoxy resin. An adhesive for wiring boards characterized by a composition comprising a crosslinking agent.