Joint structure, semiconductor device, and method of manufacturing same

A semiconductor device, comprising:

• a semiconductor element;
• and
• a substrate,
• the semiconductor element and the substrate being joined to each other through intermediation of the joint structure of claim 11.

A method of manufacturing a semiconductor device, comprising the steps of:

• preparing a paste by mixing Sn particles, Cu alloy particles containing P in an amount of 1 mass % or more and less than 7 mass %, Ag particles, and a solvent, a total amount of the Cu alloy particles and the Ag particles being set to 25 mass % or more and less than 65 mass % with respect to a total amount of the Sn particles, the Cu alloy particles, and the Ag particles, a mass ratio of the Ag particles to the Cu alloy particles being set to 0.2 or more and less than 1.2;
• applying the paste onto a substrate;
• placing a semiconductor element on the paste;
• volatilizing the solvent in the paste by heating to a temperature of 120° C. or more and 200° C. or less;
• and
• joining the semiconductor element and the substrate to each other by heating to a temperature of 340° C. or more and less than 450° C.