METAL BASE CIRCUIT BOARD AND ITS PRODUCTION PROCESS

摘要

A metal base circuit board to be used for a hybrid integrated circuit is provided. The circuit board comprises a metal plate and an insulating layer provided on the metal plate. Circuits are provided on the insulating layer and a plurality of semiconductors are mounted on the circuits. A low dielectric constant portion is provided on the metal plate under a part of the circuits on which no semiconductor is mounted. The low dielectric constant portion may be formed by providing a dent portion on the surface of the metal plate and filling the dent portion with a resin containing an inorganic filler. The side wall of the dent portion may have a gradient from 35 to 65°.