Resin containing dielectric filler for formation of built-in capactor 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

An object is to provide a dielectric layer of a double-sided copper clad laminate, for use in formation of a built-in capacitor layer, which can be formed in an optional thickness without using a skeletal material and is provided with a high strength. For the purpose of achieving the object, "a dielectric filler containing resin for use in formation of the built-in capacitor layer of a printed wiring board obtained by mixing a binder resin comprising 20 to 80 parts by weight of epoxy resin (inclusive of a curing agent), 20 to 80 parts by weight of a solvent soluble aromatic polyamide resin polymer, and a curing accelerator added in an appropriate amount according to need; and a dielectric filler which is a nearly spherical dielectric powder having perovskite structure which is 0.1 to 1.0 mum in the average particle size DIA, 0.2 to 2.0 mum in the weight cumulative particle size D50 based on the laser diffraction scattering particle size distribution measurement method, and 4.5 or less in the coagulation degree represented by D50/DIA where the weight cumulative particle size D50 and the average particle size DIA obtained by the image analysis"; and the like are used.