Low temperature ternary C4 flip chip bonding method

A method of flip chip bonding an integrated circuit chip to a chip carrier. A high melting temperature composition, such as a binary Pb/Sn alloy, is deposited on contacts on, for example, the chip, and constituents of a low melting composition, such as Bi and Sn, are codeposited on contacts on, for example, the chip carrier. The chip and chip carrier are then heated. This causes the lower melting temperature composition, for example the Bi and Sn, to melt and form a low melting temperature alloy, such as a Bi/Sn alloy. The low melting alloy dissolves the higher melting composition, as Pb/Sn. This results in the formation of a solder bond of a low melting point third composition, such as a ternary alloy of Bi/Pb/Sn.