Metal member with Ag underlayer, insulated circuit substrate with Ag underlayer, semiconductor device, insulating circuit substrate with heat sink, and method for producing metal member with Ag underlayer

摘要

An Ag underlayer-attached metallic member includes a metallic member (12) joined with a body to be joined (3) and an Ag underlayer (30) formed on a joining surface of the metallic member (12) with the body to be joined (3), the Ag underlayer (30) includes a glass layer (31) formed on a metallic member (12) side and an Ag layer (32) laminated on the glass layer (31), and an area proportion of voids in an Ag layer (32) surface of the Ag underlayer (30) is 25% or less.