Direct Bonding of Semiconductor Chip through Elastic Resin Film

Abstract

For preliminary study of the practical application of direct bonding to semiconductor device chips, we coated Si chip surfaces with elastic resin thin films. Then, using atomic diffusion bonding processing, the chips were bonded with other substrates at room temperature. Using Si chips coated with 11-μm thick polyimide thin film, bonding defects caused by external particles were reduced remarkably. Moreover, we confirmed the reduction of bonding defects when bonding with a mirror-polished stainless-steel plate with large surface roughness of 3 nm. Results obtained for Si chips bonded with mirror-polished stainless steel revealed that polyimide thin film coating on Si chips is effective at suppressing defect formation at the bonded interface caused by differential thermal expansion of the Si chips and stainless steel.