Power module substrate with Ag underlayer and power module

Abstract

A power module substrate with a Ag underlayer of the invention includes: a circuit layer that is formed on one surface of an insulating layer; and a Ag underlayer that is formed on the circuit layer, in which the Ag underlayer is composed of a glass layer that is formed on the circuit layer side and a Ag layer that is formed by lamination on the glass layer, and regarding the Ag underlayer, in a Raman spectrum obtained by a Raman spectroscopy with incident light made incident from a surface of the Ag layer on a side opposite to the glass layer, when a maximum value of intensity in a wavenumber range of 3,000 cm−1 to 4,000 cm−1 indicated by IA, and a maximum value of intensity in a wavenumber range of 450 cm−1 to 550 cm−1 is indicated by IB, IA/IB is 1.1 or greater.

Dependencies are inferred from the claim text.