JPS62140838A - Multilayer printed 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 [Technical Field of the Invention] The present invention relates to a multilayer printed board that has excellent moisture resistance and soldering heat resistance after moisture absorption.

[Technical background of the invention and its problems] In recent years, the use of glass epoxy multilayer printed boards has rapidly increased in various computers, 0AII devices, microelectronic equipment, etc., and the number of laminated layers of multilayer printed boards themselves has also increased. It is expected that the number of layers will increase.

Although such glass epoxy multilayer printed boards have various properties, they suffer from delamination due to moisture absorption. In other words, the multilayer board consists of ■Drilling holes→■Removal of copper foil from areas other than the circuit area by etching→■Through-hole plating→
A multilayer printed board is processed through the following steps: ■Solder coating → ■Component attachment → ■Soldering. After removing the copper foil, the multilayer board is processed by bath dipping in the through-hole plating process (■), and process (■). Moisture is absorbed by the humidity in the air between steps 1 and 2, and the humidity in the air between steps 1 and 2. The moisture-absorbed multilayer board is coated with ■ solder,
When soldering (2) is heated, moisture evaporates explosively, causing delamination of the board. Such a multilayer printed board has a disadvantage in that it cannot be used in terms of reliability.

[Object of the Invention] The present invention was made to eliminate the above-mentioned drawbacks, and its purpose is to provide a multilayer printed board with excellent moisture resistance and soldering heat resistance after moisture absorption.

[Summary of the Invention] As a result of intensive research aimed at achieving the above object, the present inventor has developed a phenol novolac type epoxy resin, o-cresol novolac type epoxy resin, tetrabromo bisphenol A1 and bisphenol A type epoxy resin. The inventors discovered that a multilayer printed board using an epoxy resin composition obtained by reacting under a chemical catalyst has excellent moisture resistance and solder resistance after absorbing moisture, leading to the completion of the present invention.

That is, in the present invention, the inner layer circuit board and the prepreg are alternately stacked multiple times, and the copper foil is roughly stacked on at least one side,
In multilayer printed boards that are integrally laminated and molded by heating and pressurizing, the resins constituting the inner layer circuit board and prepreg are phenol novolac type epoxy resins, 0-cresol novolac type epoxy resins, tetrabromo bisphenol A1, and bisphenol A type epoxy resins that are basic. This is a multilayer printed board characterized by being an epoxy resin composition obtained by reaction under a catalyst.

and phenol novolak type epoxy resin or O
- A multilayer printed board containing a cresol novolak type epoxy resin in an amount of 5 to 20% by weight based on the epoxy resin composition.

Examples of the phenol novolac type epoxy resin used in the present invention include YDPN638 (manufactured by Tobu Kasei Co., Ltd., trade name).

As the 0-cresol novolak type epoxy resin used in the present invention, for example, YDCN704 (manufactured by Tobu Kasei Co., Ltd.,
product name), etc.

Tetrabromobisphenol A used in the present invention is bisphenol A in which hydrogen at the phenol lo position is replaced with bromine.

or more phenol novolac type epoxy resin or 0
- Cresol novolac type epoxy resin, tetrabromo bisphenol A1 and bisphenol A type epoxy resin are reacted under a basic catalyst, and examples of basic catalysts include caustic soda, lithium salts such as lithium hydroxide, and esters such as tetramethylammonium chloride. Examples include calcium salts such as tetraammonium salts, piperidine, diethyl sodium phosphate, and calcium chloride, and amines such as n-butylamine, and these may be used alone or in combination of two or more.

The blending ratio of the phenol novolac type epoxy resin or the 0-cresol novolac epoxy resin is preferably 5 to 20% by weight based on the epoxy resin composition. If the blended layer is less than 5% by weight, the effects of the present invention cannot be obtained, and if it exceeds 20% by weight, the moldability of the prepreg will be poor and the properties of the molded multilayer printed board will also be poor, which is not preferable. Therefore, it is limited within the above range.

[Embodiments of the Invention] Next, embodiments of the present invention will be described. The invention is not limited to this example.

Example Phenol novolac type epoxy resin (epoxy fl
175) 1% by weight of bisphenol A epoxy resin (epoxy weight [1190) 42fi 1% and tetrabromobisphenol A 4611% were reacted under a basic catalyst to obtain an epoxy resin composition with ff1485 of epoxy weight. Ta. 100 parts by weight of this composition, a hardening agent dicyandiamide 3.5 type wheel, and a hardening accelerator 2-
An epoxy resin composition varnish having a solid content of 50% was prepared by dissolving 0.15 parts by weight of ethyl-4-methylimidazole in a solvent. Apply this varnish to glass cloth 7628/AS
450 (manufactured by Asahi Siebel Co., Ltd., trade name), 16
A semi-cured prepreg was produced by heating and drying at 0° C. for 3 minutes. 53Qx530mm x using this buri preg
A circuit pattern was formed using an etching resist on both sides of a 0.2 mm glass cloth epoxy resin double-sided copper-clad laminate (TLC-W-551A-0.2-70 μm manufactured by Takashiba Keikiru Co., Ltd., trade name). After removing the copper from the non-circuit portions by etching using ferric chloride and then peeling off the etching resist, the circuit pattern copper foil was surface oxidized to produce an inner layer circuit board. The inner layer circuit board and the prepreg were stacked alternately, and finally 18 μm copper foil was placed on both sides of the stack, and the temperature was 170°C and the pressure was 401Dlf/C1112.
A multilayer printed board with a thickness of 1.6 mm was produced by heating and pressurizing for 90 minutes.

Comparative Examples Araldite 8011 (manufactured by Nippon Ciba Geigy Co., Ltd., trade name) as a flame-retardant epoxy resin: 90 parts, DEN-431 (manufactured by Dow Chemical Company, trade name) as a phenol novolak type epoxy resin: 10 parts, curing agent dicyandiamide 3 parts .5 parts by weight, and curing accelerator 2-ethyl-4-
An epoxy resin composition varnish having a solid content of 50% was prepared by dissolving 0.15 parts of methylimidazole in a solvent.
Thereafter, prepregs and multilayer printed boards were manufactured in the same manner as in the examples.

After etching the multilayer printed boards manufactured in Examples and Comparative Examples to remove the copper foil on both sides,
The sample was cut into pieces and subjected to the forced moisture absorption test shown in Table 1, and the moisture absorption rate and appearance of blisters after solder float were tested. The results are shown in Table 1, and the effect of the present invention was recognized in the multilayer printed board of the present invention with less occurrence of blisters.

Table 1 $1: The number of blisters in 8 test pieces is shown after floating in a solder bath at 260'C for 30 seconds.

[Effects of the Invention] The multilayer printed board of the present invention uses an epoxy resin obtained by reacting a phenol novolac type epoxy resin, an o-cresol novolac type epoxy resin, tetrabromobisphenol A, and a bisphenol A type epoxy resin under a basic catalyst. By using the composition, it has excellent moisture resistance and soldering heat resistance after moisture absorption, and there is less occurrence of delamination of the substrate, so it is possible to have more multilayers.
Furthermore, by using this multilayer printed board, highly reliable electronic devices and the like can be manufactured.

Claims (1)

[Scope of Claims] 1. A multilayer printed board in which an inner layer circuit board and a prepreg are alternately stacked multiple times, copper foil is further stacked on at least one side, and the inner layer circuit board and the prepreg are laminated and molded together by heating and pressing. The constituent resin is an epoxy resin composition obtained by reacting a phenol novolac type epoxy resin, an o-cresol novolac type epoxy resin, tetrabromobisphenol A, and a bisphenol A type epoxy resin under a basic catalyst. Multilayer printed board. 2 Phenol novolac type epoxy resin or o-
The multilayer printed board according to claim 1, wherein the cresol novolac type epoxy resin is contained in a proportion of 5 to 20% by weight based on the epoxy resin composition.