Bonding technology using cold-rolled Ag sheet in die-attachment applications

Abstract

This work introduce a solid-state bonding technology, which uses cold-rolled Ag sheet as a bonding material for die-attachment applications. The process of cold rolling led to grain refinement of Ag sheet from the micron to sub-micron level, which provides a driving force for hillock formation on the Ag sheet. Cross-section observation revealed that cold rolled Ag sheets well bonded with the Si chip and Cu substrate by the grown hillocks. Since the Ag sheet can provide excellent electrical and thermal performances as die-attachment, this novel bonding technology can be applied to wide band-gap power devices that require high-performance interconnections.