Power module substrate, power module substrate with metal part, power module with metal part, method for producing power module substrate, and method for producing power module substrate with metal part

A method for producing a power module substrate with a metal part including a power module substrate having a circuit layer that is formed on a first surface of an insulating layer and a metal layer that is formed on a second surface of the insulating layer, and a metal part that is bonded to the metal layer side of the power module substrate, the method comprising the steps of:

• forming a first base layer, to which a bonding layer composed of a sintered body of a bonding material including at least one of metal particles and metal oxide particles is bonded, by:
• applying a glass-containing Ag paste containing a glass component onto a surface of the metal layer on the opposite side of the surface, to which the insulating layer is provided;
• and performing a heating treatment;
• applying a bonding material including at least one of metal Ag particles and Ag oxide particles onto the surface of the first base layer;
• laminating a metal part on the applied bonding material;
• and
• forming a bonding layer that bonds the first base layer and the metal part by heating the power module substrate and the metal part in a state in which the power module substrate and the metal part are laminated.