Gas cluster ion beam irradiation for wafer bonding

Abstract

Preliminary experiments of gas cluster ion beam (GCIB) irradiation for wafer bonding were conducted. Unique irradiation effects of GCIB, such as low-damage irradiation and surface smoothing effects, will be beneficial for surface activated bonding. From XPS, AFM measurements, Ar-GCIB irradiation at oblique incidence removed native oxide on Cu films efficiently without roughening. Cu-Cu bond increased with the acceleration voltage of Ar-GCIB. There is a correlation between the bond strength and the contact angle reduction due to surface smoothing and oxide removal by Ar-GCIB.