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 of which a solidus temperature is lower than a eutectic temperature of aluminum and a metal element that constitutes the bonding surface of the metal layer,
• the heat sink and the metal layer are subjected to solid-phase diffusion bonding,
• a chill layer, in which a Si phase of which an aspect ratio of a crystal grain is 2.5 or less and a crystal grain diameter is 15 μm or less is dispersed, is formed on a bonding interface side with the metal layer in the heat sink
• the thickness of the chill layer is 50 μm or greater,
• the aluminum alloy member contains Si in a range of 1 mass % to 25 mass %,
• an intermetallic compound layer is formed at a bonding interface between the metal layer and the chill layer, and
• at a bonding interface between the metal layer and the intermetallic compound layer, oxides are dispersed in a layer shape along the bonding interface.

A heat sink, comprising:

• a heat sink main body;
• and
• a metal member layer,
• wherein the metal member layer is formed from copper, nickel, or silver,
• the heat sink main body is constituted by an aluminum alloy of which a solidus temperature is lower than a eutectic temperature of aluminum and a metal element that constitutes the metal member layer,
• a chill layer, in which a Si phase of which an aspect ratio of a crystal grain is 2.5 or less and a crystal grain diameter is 15 μm or less is dispersed, is formed on a bonding interface side with the metal member layer in the heat sink main body
• the thickness of the chill layer is 50 μm or greater,
• the aluminum alloy member contains Si in a range of 1 mass % to 25 mass %,
• an intermetallic compound layer is formed at a bonding interface between the metal member layer and the chill layer, and
• at a bonding interface between the metal member layer and the intermetallic compound layer, oxides are dispersed in a layer shape along the bonding interface.