Abstract: A printed wiring board obtained by filling a non-electroconductive resin paste containing a metal powder in inner wall metallized through holes of double sided copper-clad insulating substrate, followed by curing by two steps, can mount leadless parts in high mounting density without losing a function of electroconnecting wiring layers.

Abstract: A multilayer ceramic circuit board and method of forming such circuit board are disclosed. The wiring pattern for the multilayer ceramic circuit board includes multiple-layer portions, the multiple-layer portions including first and second electrically conductive layers, respectively a tungsten layer and a copper thick film, for example, with a diffusion layer therebetween for improving adhesivity of the first and second electrically conductive layers to each other. Such multiple-layer portions are provided by providing first and second electrically conductive layers, and an intermediate layer between the first and second electrically conductive layers, and diffusing at least one component from the intermediate layer into both the first and second electrically conductive layers. Thus, a multilayer ceramic circuit board with, e.g., a firmly coupled tungsten layer and copper thick film can be provided.