Joining method using metal foam, method of manufacturing semiconductor device, and semiconductor device

A method of manufacturing a semiconductor device in which a rear surface of a semiconductor chip is disposed on one of Cu conductor patterns that are formed on both surfaces of an insulating substrate, the method comprising the steps of:

• joining, to one of the conductor patterns, a Cu metal foam sheet of three-dimensional network having open cells;
• inserting a Sn member between the metal foam sheet and the rear surface of the semiconductor chip;
• implementing heating at a temperature equal to or higher than a melting point of the Sn member;
• bringing about a diffusion reaction between the molten Sn member and the Cu member of the metal foam sheet to join the metal foam sheet and the rear surface of the semiconductor chip together;
• dissolving the inserted Sn member by the diffusion reaction;
• and
• forming a CuSn-based alloy and leaving a Cu skeleton of the metal foam sheet of three-dimensional network in a joining base material of the CuSn-based alloy.

A method of manufacturing a semiconductor device in which a Cu electric wiring member is disposed on a front surface of the semiconductor chip,

• the method comprising the steps of:
• joining, to the electric wiring member, a Cu metal foam sheet of three-dimensional network having open cells;
• inserting a Sn member between the metal foam sheet and the rear surface of the semiconductor chip;
• implementing heating at a temperature equal to or higher than a melting point of the Sn member;
• bringing about a diffusion reaction between the molten Sn member and the Cu member of the metal foam sheet to join the metal foam sheet and the rear surface of the semiconductor chip together;
• dissolving the inserted Sn member by the diffusion reaction;
• and
• forming a CuSn-based alloy and leaving a Cu skeleton of the metal foam sheet of three-dimensional network in a joining base material of the CuSn-based alloy.

A method of manufacturing a semiconductor device in which a rear surface of a semiconductor chip is disposed on one of Cu conductor patterns that are formed on both surfaces of an insulating substrate and in which a Cu electric wiring member is disposed on a front surface of the semiconductor chip, the method comprising the steps of:

• joining, to one of the conductor patterns, a first Cu metal foam sheet of three-dimensional network having open cells, and joining, to the electric wiring member, a second Cu metal foam sheet of three-dimensional network having open cells;
• inserting a first Sn member between the first metal foam sheet and the rear surface of the semiconductor chip, and also inserting a second Sn member between the second metal foam sheet and the front surface of the semiconductor chip;
• implementing heating at temperatures equal to or higher than melting points of the first and second Sn members;
• bringing about a diffusion reaction between the first and second molten Sn members and the Cu members of the metal foam sheets, to join the metal foam sheets and the rear and front surfaces of the semiconductor chip together, respectively;
• dissolving the first and second inserted Sn members by the diffusion reaction;
• and
• forming a CuSn-based alloy and leaving a Cu skeleton of each of the metal foam sheets of three-dimensional network in a joining base material of the CuSn-based alloy.