RESIN CONTAINING DIELECTRIC FILLER FOR FORMATION OF BUILT-IN CAPACITOR LAYER OF PRINTED WIRING BOARD, COPPER DOUBLE CLAD LAMINATE HAVING DIELECTRIC LAYER FORMED WITH RESIN CONTAINING DIELECTRIC FILLER, AND PROCESS FOR PRODUCING COPPER DOUBLE CLAD LAMINATE

摘要

A dielectric layer of copper double clad laminate that is used for formation of a built-in capacitor layer and that enables formation of any arbitrary layer thickness without the use of a skeletal member and exhibits a high strength. In the dielectric layer, use is made of, for example, a resin containing dielectric filler for formation of built-in capacitor layer of printed wiring board, obtained by mixing together a binder resin, the binder resin composed of 20 to 80 parts by weight of epoxy resin (containing hardening agent) and 20 to 80 parts by weight of solvent-soluble aromatic polyamide resin polymer optionally together with a hardening accelerator added in an appropriate amount according to necessity, and a dielectric filler, the dielectric filler being an approximately spherical dielectric powder of perovskite structure having an average particle diameter (D1A) of 0.1 to 1.0 μm, a weight cumulative particle diameter (D50), as measured in accordance with a laser diffraction scattering type particle size distribution measuring method, of 0.2 to 2.0 μm and an aggregation degree, in terms of D50/D1A wherein D50 is a weight cumulative particle diameter and D1A is an average particle diameter determined by image analysis, of 4.5 or below.