JPS63211796A - Manufacture of multilayer laminated 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 Field of the Invention The present invention relates to a method for manufacturing a multilayer laminate having a printed circuit in a plurality of layers.

Conventional technology Conventionally, multilayer laminates have been manufactured using a double-sided printed wiring board made by etching a double-sided copper-clad laminate with a predetermined circuit. Copper foil is bonded under heat and pressure to the surface of two sheets of prepreg to form an integrated structure.

Problems to be Solved by the Invention However, in the conventional manufacturing method, the manufacturing process is complicated due to the use of prepreg for bonding the surface copper foil and the need for blackening treatment on the surface of the inner layer circuit. Furthermore, in order to prevent voids from remaining in the laminate during the process of integrating the surface copper foil, it is necessary to apply high pressure, which requires large equipment.

The object of the present invention is to manufacture a void-free multilayer laminate using a simple process.

Means for Solving the Problems In order to achieve the above object, the present invention uses a double-sided printed wiring board whose circuits are made of double-sided roughened copper foil as an inner layer circuit. A mixture of 1 to 20 parts by weight of a microcapsulated room-temperature curing agent based on 100 parts by weight of a solvent-free epoxy resin composition is applied to the surface, and the microcapsules are thermally melted by primary heating. The method is characterized in that the copper foil is then bonded and integrated with the coated surface by secondary heating and pressurization.

Function: The room temperature curing agent used in the present invention includes diethylenetriamine, triethylenediamine, ethylenediamine, and the like. The material used to encapsulate these to form microcapsules is polystyrene, polyethylene, etc., and the capsule wall melts during primary heating, exposing the room-temperature curing agent and acting on the epoxy resin to perform semi-curing. As a result, a uniform insulating film is formed, and the copper foil is firmly bonded by the subsequent secondary heating and pressurization.

If the amount of the room temperature curing agent is less than 1 part by weight, uniformity of the insulating film cannot be expected when adhering the copper foil, and short circuits are likely to occur between the inner layer circuit and the surface circuit. Moreover, if it exceeds 20 parts by weight, the curing reaction becomes rapid and voids occur.

Examples The solvent-free epoxy resin used in the present invention may be an ordinary liquid epoxy or solid epoxy, but it is desirable that the viscosity at the time of coating is 10 to 600 poise.

If the viscosity during coating is low, a uniform insulating layer cannot be obtained, and if the viscosity is high, voids are likely to occur. An inorganic filler may be added to the solvent-free epoxy resin.

Pico) 1001, manufactured by Shell Chemical) 100 parts by weight,
Four parts of dicyandiamide, 0.6 parts by weight of 2-r-thyl-4-methylimidazole, and microencapsulated diethylenetriamine were blended in the amounts shown in Table 1, and 9
Stirred at 0°C for 5 minutes. The above formulation was applied to a thickness of 0.21 on both surfaces of a double-sided printed wiring board whose circuitry was made of double-sided roughened copper foil.

A copper foil with a thickness of 18 .mu.m was placed on this coated surface and was heated primarily at 120.degree. C. to melt the microcapsules and perform semi-curing. Thereafter, it was subjected to secondary heating at 150°C, and the copper foil was bonded together under a pressure of 5 kg/- to obtain a multilayer laminate.

Its properties are also shown in Table 1.

Comparative Example 3 A prepreg prepared by blending 100 parts by weight of the epoxy resin used above with 4 parts by weight of dicyandiamide = 0.3 parts by weight of 2-ethyl-4-methylimidazole was applied to a plain-woven glass cloth and dried to form a B-stage. prepared. Copper foils with a thickness of 18 μm were placed on both surfaces of the double-sided printed wiring board used above via the prepreg, and were integrated by heating and pressing to obtain a multilayer laminate. Its characteristics are shown in Table 1.

Table 1 Effects of the Invention As mentioned above, the present invention simplifies the process because it does not use prepreg to bond and integrate the surface copper foil, and also has the advantage of being able to manufacture a multilayer laminate with fewer voids, and its industrial advantages. The value is extremely great.

Claims (1)

[Claims] A mixture of 1 to 20 parts by weight of a microencapsulated room-temperature curing agent per 100 parts by weight of a solvent-free epoxy resin composition is applied to the surface of a double-sided printed wiring board whose circuit is made of double-sided roughened copper foil, and A method for producing a multilayer laminate, comprising thermally melting microcapsules by heating, and then bonding copper foil to the coated surface by secondary heating and pressure.