LIQUID THERMOSETTING RESIN COMPOSITION, PRINTED WIRING BOARDS AND PROCESS FOR THEIR PRODUCTION

摘要

A liquid thermosetting resin composition comprises (A) an epoxy resin, (B) a curing catalyst, and (C) a filler and is characterized by exhibiting a viscosity at 25°C of not more than 1,500 dPa.s, a gel time of not less than 300 seconds at a temperature at which the composition exhibits a melt viscosity of not more than 10 dPa.s, and a gel time at 130°C of not more than 600 seconds. In the production of a printed wiring board by superposing an interlaminar resin insulating layer and a conductive circuit on the surface of the wiring board having a conductive circuit pattern including hole parts, a hole filling process is performed by filling the hole parts mentioned above with the composition mentioned above, effecting precure of the composition by heating, then polishing and removing parts of the precured composition protruding from a surface defining the hole parts, and further heating the precured composition till final curing. In such a way, it is possible to carry out the filling of such holes as via holes and through-holes of the printed wiring board with high operational efficiency.