JPS62223276A - Insulating film material for printed circuit - Google Patents

Abstract

PURPOSE:To provide the titled insulating film material having excellent migration resistance, by blending a liquid epoxy resin with a specified dihydrazide compd. CONSTITUTION:An epoxy resin (A) having at least two epoxy groups per molecule is blended with a dihydrazide compd. (B) of formula I (wherein R is a group of formula II or III; R' is an alkyl or an aryl; R'' is H, an alkyl or an aryl) in an amount of 0.1-0.4mol of the dihydrazide group per mol of the epoxy group of the component A, 0-30wt% inorg. filler (C) and optionally, a leveling agent, a viscosity modifier, a curing accelerator, etc. (D).

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] This invention belongs to the field of printed circuit board manufacturing technology. It also succumbs to the technical challenges of epoxy resin compositions.

[Background technology] The recent development of electronics has required higher density and higher reliability for printed circuit boards, and various new materials, manufacturing methods, and
Methods have been proposed and tried. For example, from the conventional single-sided printed circuit boards made of paper-phenolic resin laminates, to double-sided printed circuit boards made of glass-epoxy resin laminates for use in fields that require high reliability and high density, and then to glass-epoxy resin laminates. - Development is progressing toward multilayer printed circuit boards using a combination of epoxy resin, glass, and polyimide resin.

These advances have also caused a significant increase in the cost of printed circuit boards, and the emergence of low-cost printed circuits in addition to high density and high reliability has become desirable.

One solution to such problems is the proposal of a single-sided multilayer printed circuit (hereinafter referred to as SMC) A. As shown in Figure 1, this is possible without using a double-sided copper face plate.
Further, a circuit is formed from a single-sided substrate as the organic substrate 1 by build-up without using the through-hole method, thereby making cross wiring possible.

That is, the first wiring 3 is formed on the organic substrate 1, the insulation N2 is formed on a part of the first wiring 3, and the second wiring 4 is formed thereon to complete the cross wiring. In a simple circuit, as shown in FIG.
It is possible to provide the function of a double-sided board by simply creating a layered structure.

This method is commonly used for ceramic substrate HIC, but in that case, a glass layer is used as an insulating layer and high temperature treatment is performed, so this method can also be used for organic substrates. I can't. Therefore, when using an organic insulating film, on the one hand, high reliability is required as described above, so the reliability of the insulating film has become a problem. The reliability of printed circuit boards includes heat resistance, insulation, and migration resistance. Epoxy resin substrates have excellent migration resistance, which is one of the important reasons why they are used in place of phenolic resin substrates.

In general, phenolic resin insulating films are more prone to migration than epoxy resin insulating films, especially silver (A).
Although it is remarkable in the case of g), a similar tendency is also exhibited in the case of 5liI(Cu). From this point of view, it is usually recommended to use an epoxy resin insulating film.

In the SMC method, plating methods (for example, copper), silver paste methods, and the like can be considered as wiring methods for the second layer, but the latter is preferable from the viewpoint of workability.

In addition, in such cases, since the insulating layer is generally thin (several 1
0 micron), migration resistance is an important factor in both plating and silver paste methods.

On the other hand, insulating pastes, solder resists, etc. are conveniently used as organic insulating films, but even if epoxy resin insulating films are used, sufficient migration resistance cannot be ensured, as can be understood from the above circumstances. Therefore, the spread of the SMC method has been hindered.

[Object of the Invention] An object of the present invention is to provide an interlayer insulating film for printed circuits made of epoxy resin with excellent migration resistance.

[Disclosure of the Invention] The present invention provides an insulating film material for printed circuits, which is made by blending a liquid epoxy resin containing two or more epoxy groups in one molecule and a dihydrazide compound having the following structure. .

Clarification of the specification (no change in content) The aim is to obtain an insulating film with excellent migration resistance by curing the epoxy resin using the following methods.

In addition to the above-mentioned curing agent, the present invention also provides additives that are generally used as additives to compositions for forming insulating films.
For example, surfactants such as leveling agents to improve film-forming properties, additives to provide sealing properties, and additives to provide screen printability. Furthermore, viscosity modifiers, curing accelerators, pigments, dyes, etc. may be added.

Any epoxy resin may be used, such as bisphenol A epoxy resin, alicyclic epoxy resin, etc.
It is preferable to use liquid ones. However, even if solid or highly viscous epoxy resins such as bisphenol A type, phenol novolak type, Talezol novolac type epoxy resin, brominated epoxy resin, rubber-modified epoxy resin, etc. are used together, the whole remains liquid. It doesn't matter if you present it.

As the curing agent, a dihydrazide compound represented by the above general formula is used. Examples include adipic acid dihydrazide, sepatic acid dihydrazide, isophthalic acid dihydrazide, etc., or dihydrazides represented by the following formula. In the above formula, when R'' is a methyl group, it is abbreviated as: 14HT. .

The amount of addition is preferably such that the number of dihydrazide groups is 0.1 to 0.4 per epoxy group,
If the number is 0.4 or more, unreacted dihydrazide remains and water resistance is unfavorable. If the number is less than 0°, the effects intended by the present invention cannot be obtained.

It is preferable that the inorganic filler is not included or is contained in an amount of 30% by weight or less. If a large amount is blended, not only will the film formability deteriorate, but also the matching of the insulating film with the organic substrate will be poor, and the film will also tend to become too hard and have poor adhesion.

The following will explain based on examples.

Example 1 100 parts by weight of Epikote 828 (trademark Nijinyl chemical side layer, epoxy equivalent: 185), 18 parts by weight of 2.4HT, 3 parts by weight of Aerosil #30, and 1 part by weight of a silane coupling agent were blended. Mixing is done using a vacuum seeding machine.
The mixture was mixed for 2 hours to obtain a composition for a glabella insulating film material. This was used to evaluate as follows.

That is, as shown in FIG.
is formed by etching, and a part of the insulating film material 7 is formed on the copper pattern 5 using a spacer as shown in FIG.
was applied uniformly to a thickness of 30 to 50 μm. Curing was performed by heating at 160° C. for 8 hours. after that,
As shown in FIG. 5, a pattern 8 of silver paste was formed, 15 VDC was applied to the upper and lower conductive layers, and the pattern was left in an atmosphere of 85° C. and 85% for 1000 hours. This substrate was cut along the broken line XX in FIG. 5, and the presence or absence of migration was observed.

Example 2 The same procedure as in Example 1 was carried out except that 2,4HT used in Example 1 was changed to 9 parts by weight.

Example 3 Instead of 18 parts by weight of 2,4HT used in Example 1,
6 parts by weight of 2.4HT, imidazole compound (2MA
-OK: Shikoku Kasei@) was used in the same manner as in Example 1, using 1.5 parts by weight.

Comparative Example 1 The same procedure as in Example 1 was carried out, except that 5 parts by weight of an imidazole compound (2MA-OK: Shikoku Kasei@) was used in place of 2.4HT in Example 1.

Comparative Example 2 The same procedure as in Example 1 was carried out except that 8 parts by weight of dicyandiamide was used in place of 2,4HT used in Example 1.

Comparative Example 3 100 parts by weight of epoxy acrylate (trademark: UE-8200, Dainippon Ink Till), 3 parts by weight of Aerosil #300, 1 part by weight of silane coupling agent, 2 parts by weight of benzoin ethyl ether, 10 parts by weight of talc. The same procedure was carried out. Note that curing was performed by irradiation with Uv light.

Example 4 Epicoat 828 (trademark Nigel Chemical (manufactured by! Zero) 7
The process was carried out in the same manner as in Example 1 except that 30 parts by weight of 0 weight J5HH5, Epicoat 1004 (trademark Nigel Chemical US!), 1 part by weight of a silane coupling agent, and 15 parts by weight of adipic acid dihydrazide were blended. .

Example 5 A test was carried out using 18 parts by weight of sebacic acid dihydrazide in place of adipic acid dihydrazide in Example 4.

Example 6 A test was carried out using 18 parts by weight of isophthalic acid dihydrazide in place of adipic acid dihydrazide in Example 4.

When the above Examples and Comparative Examples were evaluated, it was found that in Comparative Example 1, silver migration occurred to the point where the upper and lower conductive layers were on the verge of short-circuiting.

In Comparative Example 2.3, migration was observed here and there between the upper and lower conductive layers. In contrast, Example 1~
6, no migration was observed at all.

[Effects of the Invention] This invention is made by blending a liquid epoxy resin containing two or more epoxy groups in one molecule with a specific dihydrazide compound, so it can be used for printed circuit boards with improved migration resistance. We were able to provide insulating film materials.

[Brief explanation of drawings]

Figure 1 is a sectional view of the main part of a printed circuit board showing an example of SMC, Figure 2 is a plan view of the main part of the printed circuit board showing the state of cross wiring in SMC, and Figure 3 is precious metal plating on the wiring pattern. Fig. 4 is a plan view of the main part of the printed circuit board showing an example of applying insulation film, Fig. 5 is a plan view of the main part of the printed circuit board showing the part to which the insulating film is applied, and Fig. 5 shows the cut section for migration testing. FIG. 2 is a plan view of essential parts of the printed circuit board shown in FIG. 1 is an organic substrate 3 is a first wiring layer 2 is an insulating film 4 is a second wiring layer Patent applicant Patent attorney representing Matsushita Electric Works Co., Ltd. Toshimaru Takemoto (and 2 others) Procedure Nei1? Seisho (Hōri June 24, 1988, Rokun 1961 Patent Application No. 066457 2, Name of Invention Insulating Film Material for Printed Circuits 3, Relationship with Amendment Case Patent Applicant Address Kadoma, Osaka Prefecture Address: 1048 Kadoma, Ichi-Oaza Name: (583) Matsushita Electric Works Co., Ltd. Representative: Sadao Fujii 4, Agent

Claims (2)

[Claims] (1) An insulating film material for printed circuits comprising a liquid epoxy resin containing two or more epoxy groups in one molecule and a dihydrazide compound having the following structure. NH_2NH-R-NHNH_2 However, R is ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ or ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ R' is an alkyl group or aryl group R'' is hydrogen, an alkyl group, or an aryl group (2) Add a dihydrazide compound to 1 mole of epoxy group in the epoxy resin, and the dihydrazide group is 0.1 to 0.4
The insulating film material for printed circuits according to claim 1, characterized in that the ingredients are blended in molar amounts.