Low temperature ternary C4 method.

摘要

Flip chip bonding an IC chip to a carrier comprises depositing a high m.pt. compsn. on one set of contacts and a lower m.pt. compsn. on the facing contacts, and heating in contact to form a still lower m.pt. compsn. by the lower m.pt. compsn. dissolving the higher, and solder bonding with this alloy. Also claimed is a method as above in which Pb/Sn alloy is deposited on chip contacts, Bi/Sn alloy co-deposited on the carrier contacts, and the low m.pt. ternary Pb/Sn alloy forms the solder bond.