Diffusion joining method and a paste used therefor

摘要

The present invention relates to a diffusion joining method of Cu or Cu alloy surface and a conductive paste used therefor, especially applied to a method for preparing a multilayer printed wiring board. The present invention is characterized by providing the contacting surfaces with a layer selected from the group comprising a noble metal thin layer, a metal oxide remover layer and a conductive paste layer mainly consisting of a Cu or Cu alloy particles and the metal oxide remover; and pressing the contacting metal surfaces at a temperature higher than 170 DEG C. more or less whereat the Cu atom at interface of the Cu or Cu alloy surfaces to be joined becomes to be able to diffuse, to give a joined metal body.