Solder paste and bonded structure

Abstract

A solder paste including at least two types of solder powders each containing at least two types of metal elements has an average free energy of oxide formation of the at least two types of solder powders on a molar basis of −490 kJ/mol or more, the average free energy of oxide formation being a sum of products (Ai×Bi) of a molar ratio (Ai) of each of the at least two types of metal elements (i) based on all the at least two types of metal elements constituting the at least two types of solder powders included in the solder paste and a free energy (Bi kJ/mol) of oxide formation of the each of the at least two types of metal elements, and an average melting point of the at least two types of solder powders on a mass basis of 121° C. or lower, the average melting point being a sum of products (Cj×Dj) of a mass ratio (Cj) of each of the at least two types of solder powders (j) based on a total mass of the at least two types of solder powders included in the solder paste and a melting point (Dj° C.) of the each of the at least two types of solder powders.

Dependencies are inferred from the claim text.