Pressureless Ag Thin-Film Die-Attach for SiC Devices

Abstract

The electronic packaging has developed in the changing trend from soldering to solderless technology bonding to achieve higher performance of devices. Moreover, power electronic devices have searching for an alternative interconnection technology to replace the high temperature solder with high Pb contents, particularly suitable for next-generation wide band-gap (WBG) semiconductors such as SiC or GaN. In this study, our pressureless Ag thin-film die-attach gives an opportunity to produce the mass production by realizing low-temperature process. We demonstrate the pressureless Ag thin-film die-attach with Si and SiC to explain the mechanisms underlying the bonding process. The variation of the substrate material modifies the thermal expansion mismatch between sputtered Ag film and the substrate, and changes the bonding property, in particular die-shear strength. We reveal that the thermal stress generated by heating plays one of key roles to control the pressureless Ag thin-film die-attach process.