Dielectric filler containing resin for use in formation of built-in capacitor layer of printed wiring board and double-sided copper clad laminate with dielectric layer formed using the same dielectric filler containing resin, and production method of double-sided copper clad laminate

Abstract

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 μm in the average particle size D, 0.2 to 2.0 μm in the weight cumulative particle size Dbased on the laser diffraction scattering particle size distribution measurement method, and 4.5 or less in the coagulation degree represented by D/Dwhere the weight cumulative particle size Dand the average particle size Dobtained by the image analysis'; and the like are used.