Bonded body, substrate for power module with heat sink, heat sink, method for producing bonded body, method for producing substrate for power module with heat sink, and method for producing heat sink

A power module substrate with heat sink, comprising:

• an insulating layer;
• a circuit layer that is formed on one surface of the insulating layer;
• a metal layer that is formed on the other surface of the insulating layer;
• and
• a heat sink that is disposed on a surface, which is opposite to the insulating layer, of the metal layer,
• wherein in the metal layer, a bonding surface with the heat sink is constituted by copper, nickel, or silver,
• in the heat sink, a bonding surface with the metal layer is constituted by an aluminum alloy in which a concentration of Si is in a range of 5 mass % to 25 mass %,
• the heat sink and the metal layer are subjected to solid-phase diffusion bonding,
• a compound layer, which is formed through diffusion of Al of the heat sink and a metal element that constitutes the bonding surface of the metal layer, is provided at a bonding interface between the heat sink and the metal layer, and
• a Mg-concentrated layer, in which a concentration of Mg is 4.9 mass % or greater in a region that ranges from the bonding surface to 50 μm in the depth direction, is formed at the inside of the compound layer, and the thickness of the Mg-concentrated layer is in a range of 1 μm to 30 μm.

A heat sink, comprising:

• a heat sink main body;
• and
• a metal member layer that is bonded to the heat sink main body,
• wherein the metal member layer is formed from copper, nickel, or silver,
• the heat sink main body is constituted by an aluminum alloy in which a concentration of Si is in a range of 5 mass % to 25 mass %,
• the heat sink main body and the metal member layer are subjected to solid-phase diffusion bonding,
• a compound layer, which is formed through diffusion of Al of the heat sink main body and a metal element that constitutes the metal member layer, is provided at a bonding interface between the heat sink main body and the metal member layer, and
• a Mg-concentrated layer, in which a concentration of Mg is 4.9 mass % or greater in a region that ranges from the bonding surface to 50 μm in the depth direction, is formed at the inside of the compound layer, and the thickness of the Mg-concentrated layer is in a range of 1 μm to 30 μm.