JPS58119692A - Printed circuit board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a printed wiring board using an aluminum-based insulating substrate.

(Technical Background of the Invention and Problems thereof) - In general, insulating substrates for printed wiring boards include paper-based phenol resin laminates, paper-based epoxy resin laminates, and glass-based epoxy resin laminates. A synthetic resin laminate is used.

However, since such insulating boards have poor heat dissipation properties, heat generated from the wiring circuits and their mounted components is likely to accumulate on the board, causing the temperature of the circuits to rise. This was a contributing factor to lower reliability.

In addition, printed wiring boards using such synthetic resin laminates have poor dimensional stability and are highly hygroscopic during soldering, which tends to cause the board to warp or twist due to heat. There was a problem in that the insulation properties between the wirings were likely to deteriorate.

In view of these problems, attempts have been made in recent years to use aluminum plates as substrates for printed wiring boards, especially in fields where good heat dissipation is required. Up until now, it has been impossible to obtain an ideal printed wiring board because the insulating layer is formed far apart.

On the other hand, the N -N'-substituted maleimide compound was heated and 4
It is known that an insulating resin with excellent heat resistance can be obtained by this method, but this resin is extremely brittle and easily cracks due to repeated cooling and heating cycles, making it impossible to put it to practical use as it is.

Recently, N-N'-substituted maleimide compounds have been developed using vinyl monomers, epoxy resins, unsaturated polyester resins, and N-N'-substituted maleimide compounds.
- By using a substituted motumaleimide compound etc. in combination,
A solvent-free phenol that improves the heat resistance and flexibility of the above resins has been developed, but since N/N'-substituted maleimide compounds are solid at room temperature and have poor affinity for solvents, this maleimide compound is crystallized. It had the disadvantage of being easy to precipitate.

In addition, such phenol has a high viscosity and needs to be heated to high temperature to impart fluidity during coating 4 and processing, and also has low adhesion to the aluminum plate, so it cannot be used as an insulating layer in printed wiring boards. There wasn't.

(Objective of the Invention) The present invention has been made in view of these points, and is based on an aluminum plate that has high heat dissipation properties and is free from deformation due to heat and insulation deterioration due to moisture absorption. The purpose of the present invention is to provide an ideal printed wiring board using an insulating substrate coated with an insulating varnish having excellent properties and flexibility.

(Summary of the Invention) That is, the present invention provides a resin comprising (a) a bismaleimide compound and a triazine resin as main components;
) An epoxy resin dissolved in (C) a reactive diluent containing an unsaturated monomer having a glycylydyl group, which has excellent electrical insulation, heat shrinkage resistance, and shock resistance, and is easy to process. This invention relates to a printed wiring board formed by applying an improved insulating varnish onto an aluminum plate and curing it to provide an insulating layer, on which a conductive circuit is formed.

In the printed wiring board of the present invention, the resin (1) which is mainly composed of bismaleimide and triazine resin resin used for preparing the insulating phenol is a bismaleimide represented by the general formula, and a resin represented by the general formula %. % of dicyanate, as well as triazine resins which are cyclopolymerized with three or more molecules of dicyanate and have a tri(dianate group (N=C-0-) in the molecule, for example, the following structural formula) (However, Arl and Arc represent the same or different divalent aromatic groups.)

Examples of such resin include B manufactured by Mitsubishi Gas Chemical Co., Ltd.
There is T resin.

BT resin is triazine A developed by Bayer AG, West Germany.
These resins are heat-resistant addition-polymerizable thermosetting resins whose main raw materials are resin and bismaleimide, and these resins are manufactured as follows.

Margin below ” Arc~ CH.

111 BT Resin It is estimated that the molecular structure of BT resin after curing is as follows.

The following brands of such T-resin are commercially available, and any of them can be used in the present invention.

1T210050~ω1.24 brown 260 175
172400 50-60 1.28 Dark brown
2 (capital) Colder 1?2600 50-60 1.
31 Dark brown 310mBTZ&)0 65~?
5 1.34 Dark brown 320 230 Among the epoxy resins used in the present invention, those that are industrially produced and can be effectively used in the present invention include, for example, the following bisphenol diepoxy resins. There is a de.

Shell Chemical Co., Epicote (Shi1@-) 827.8
28.834.1001.1002.1004.100
7.1009, Dow Chemical Company, D, 1. R330%
D,! , 凰331, D, 1. R332, D, set R334
,D,1.1335%DJ,ll 336,D.

1.11337, DJC, Im 66G, D, lJ
Q61, t), E, R662, D, 1. B 667,
D, 1.166g, D, 1. R669, Chihakaigy Co., Ltd., Araldite (Mraldlt*) GY 25
0, GY260, GY286.6071.6084.
6097.6099, J@MI Ds>bag, 1p
l-R @ Tomi 510.5101, Dainippon Ink & Chemicals Co., Ltd., Ebiku o y 810, 100G, 1010
゜3010 (all of the above are product names). Furthermore, in the present invention, it is possible to further improve the mechanical properties and heat resistance by using, as the epoxy resin, a novolac type epoxy resin having an average number of EVO+V groups of 3 or more, for example, a novolak type epoxy resin.

The novolac type epoxy resin used has a molecular weight of 5.
00 or more is suitable.

Examples of commercially produced novolak-type epoxy resins include the following: Tepa Geigy, Araldite.
EPN1138, EPN1139, ECN1273
, ICN1280°1i:cN1299, Dow Chemical Company, IJ, N431.

D, E, N 438, V z A' Kagakusha, Kplkete 152.154. Union Carbide Corboley i/ =a 7 companies, ERR-0100
, ERRBO447, IRLII0448° and above can be used alone or in combination of two or more.

The blending ratio of the resin mainly composed of bismaleimide and triazine resin monomer (a) and the epoxy resin (b) is preferably in the range of 10:90 to 90:10 (weight ratio), Another 30:70
~70:30 (it is desirable that the fi weight ratio be in the range).

If the blending ratio of component (a) is less than 10% by weight, the heat resistance of the obtained face will be poor, and conversely, if the blending ratio of component (b) is less than 10% by weight, the viscosity of the face will become high, resulting in workability. becomes worse.

Furthermore, as a reactive diluent, an unsaturated monomer having a glycidyl group such as methacrylic acid glycidyl ester, acrylic acid glycidyl ester, or allyl glycidyl ether, or an unsaturated monomer that can be heat-polymerized with this unsaturated monomer such as diallyl phthalate is used. Examples include mixtures with other monomers.

When using the latter mixture, the unsaturated monomers having glycidyl groups are present in the mixture in an amount of at least 1 G (by weight).
It is desirable that the content be more than 10%.
(wt)% or less, the copolymerizability between the respective components becomes insufficient, resulting in deterioration of the physical properties after the face is cured.

In addition, the blending ratio of such a reactive diluent to the resin component C2 of (a) and (b) is as follows:
) The amount of the reactive diluent is preferably in the range of 5 to 100 parts by weight, more preferably in the range of 10 to 60 parts by weight, per 100 parts by weight of the epoxy resin.

If the amount of the reactive diluent is less than 5 parts by weight, it may not be sufficient to reduce the viscosity of the resin to the required level, and if it exceeds 100 parts by weight, the heat resistance of the cured resin may deteriorate. Two.

In the above compounding range, the insulating face obtained is
It has a viscosity that is ideal for dip coating or screen printing on aluminum plates, and forms an insulating layer that is not only easy to work with but also has excellent heat resistance, electromechanical properties, and adhesion. be done. In addition to the above-mentioned components, a known curing catalyst may be added to the insulating face used in the present invention.

As a curing catalyst, common polymerization initiators such as benzoyl peroxide, dicumyl peroxide, jeter-shut-butyl peroxide, azobiziisobuteronitrile, etc., and as accelerators, 83-class amines, imidazoles, and organic metal salts are used. , chloride, etc. are used as appropriate.

In addition, if necessary, a filler consisting of an inorganic powder such as Y9 powder, mica powder, or carbon powder, or a resin powder such as polyimide powder or polytetrafluoroethylene powder may be added to improve the heat shrinkability of the cured coating film. or improve thermal conductivity.

Furthermore, in order to change the physical properties of the resulting coating film as necessary, a modifying resin may also be blended as appropriate.

Examples of these modifying resins include unsaturated polyester resins and epoxy acrylate resins, and the amount added is preferably an amount that does not deteriorate the heat resistance of the cured product, that is, not more than SO (weight) % of the entire resin component.

In the present invention, such an insulating face is applied onto a 741 minium board and cured by heating, but the curing temperature is preferably in the range of 10°C to 10°C.

It is thought that by such heat curing treatment, each reactive component in the varnish reacts and is crosslinked and cured in the following reaction format.

Formation of triazine ring by self-addition reaction of O-triazine resin monomer: Ar1 - Formation of triazine ring by addition reaction of O-triazine resin monomer and bismaleimide: Formation of oxazole ring by addition reaction of O-triazine resin monomer and glycidyl group: 0 reaction Production of a crosslinking reaction product through a radical reaction between an unsaturated monomer used as a diluent and bismaleimide The printed wiring board of the present invention is produced using a solvent-free insulating varnish configured as described above. For example, to get it:

That is, first, this insulating varnish is printed on an aluminum plate using a 150-mesh Tetron screen and cured by heating.

A coating layer with a thickness of 15 to 18 microns is formed in one printing, and finally a uniform coating layer with a thickness of 30 to 40 microns is formed in a second printing.

The curing conditions are 180° C. for 1 hour.

In order to form a conductive circuit on the insulating layer obtained in this way, a method of printing conductive paste using a screen,
Alternatively, there is a method of mechanically or chemically treating the surface of the insulating layer and forming a circuit by electrolytic plating or electroless plating.

(Effects of the Invention) The printed wiring board of the present invention not only uses an aluminum plate with high heat dissipation properties and no deformation or moisture absorption as a substrate, but also has an insulating eyelid film provided thereon that is heat resistant and electrically insulating. It can be said to be an ideal printed wiring board because it has excellent adhesiveness and adhesion to the substrate.

Therefore, variable elements such as resistors and capacitors and active elements such as transistors can be attached to the circuit, and it can be widely used as a hybrid integrated circuit.

(Embodiments of the Invention) Example 1 50 parts by weight of BT210G (100% resin content) was added to 30 parts by weight of Epikote 828 and dissolved by heating, and then 20 parts by weight of glycidyl methacrylate (glycidyl methacrylate) was added and mixed uniformly. It was made into a solution.

In this solution, 0.1 part by weight of zinc octylate was added as an accelerator.
0.5 parts by weight of dicumyl peroxide was added as a curing catalyst to obtain a solvent-free adhesive for electrical insulation with a viscosity of 4 voids and 9 at 25°C.

This varnish was printed on an aluminum plate with a thickness of 2 cm using a 150 mm silk screen, and
It was cured by heating for a period of time.

This operation was repeated twice to obtain an insulating substrate having an insulating layer with a thickness of 35 tones.

Furthermore, a conductive paste was screen printed on the insulating layer to form a conductive circuit.

Example 2 65 parts by weight of Epicote 152 and 2 parts of B T 2100
After adding 0 parts by weight and heating and dissolving, 30 parts by weight of glycidyl methacturate was added to form a uniform mixed solution.

In this solution, 0.1 part by weight of zinc octylate was added as an accelerator.
0.5 parts by weight of dicumyl peroxide was added as a curing catalyst to obtain a solvent-free varnish for electrical insulation having a viscosity of 7 poise at 25°C.

A printed wiring board was manufactured using this varnish in the same manner as in Example 1.

Example 3 BT-2600 was added to 30 parts by weight of Epicote 828.
After adding and heating and dissolving 40 parts by weight, 20 parts by weight of glycidyl methacrylate and 10 parts by weight of diallyl phthalate were added to form a uniform mixed solution.

In this solution, 0.1 part by weight of zinc octylate was added as an accelerator.
0.5 parts by weight of dicumyl peroxitide was added as a curing catalyst to obtain a solvent-free type PHEO for electrical insulation having a viscosity of 20 poise at 25°C.

A printed wiring board was manufactured in the same manner as in Example 1 using this film.

Comparative Example A normal epoxy resin solution was prepared by adding 39 parts by weight of hexahydrophthalic anhydride and 1 part by weight of triethylamine to 61 parts by weight of Epicote 828.

This resin solution was applied and cured on an aluminum plate in the same manner as in Example 1, and a conductive circuit was formed on top of the resin solution to produce a printed wiring board.

Next, the characteristics of the insulating layers in the printed wiring boards obtained in Examples 1 to 3 and Comparative Example were tested.

The test results are shown in the table.

table

Claims (1)

[Claims] 1. Reaction of (a) a resin mainly composed of bismaleimide and a triazine resin monomer and (I) an epoxy resin containing (C) an unsaturated monomer having a glycidyl group. 1. A printed wiring board characterized in that an insulating pheophonate dissolved in a diluent is applied onto an aluminum plate and cured, and a conductive circuit is formed thereon. 2. The blending ratio of (a) resin mainly composed of bismaleimide and triazine resin monomer and (b) epoxy resin is 10:90 to 90:1 by weight.
The printed wiring board according to claim 1, which is within the range of 0. 5. (a) The resin mainly composed of bismaleimide and triazine resin monomer is composed of bismaleimide represented by the general formula 0% and the general formula N=CO)Lr.
Dicyanate represented by 20CmiN (wherein Arl and Arc represent the same or different divalent aromatic groups) and triazine rings in the cyclopolymerized molecule of three or more molecules of this dicyanate. Claim 1 comprising a mixture of triazine resins having cyanene and -t groups at the molecular terminals.
The printed wiring board according to item 1 or 2.