Effect of Atmospheric Pressure Plasma Treatment on Transverse Ultrasonic Bonding of Gold Flip-Chip Bump on Glass Substrate

摘要

This study was focused on the effect of atmospheric pressure plasma treatment conditions on the ultrasonic bonding properties of Au flip-chip bumps on Au-finished glass substrates. The spreading test of de-ionized (DI) water was carried out on the substrate after the treatment. The plasma treatment was performed with three different gases, N_2, N_2 + O_2, and N_2 + H_2, for various treatment times from 0.3 to 18 s. The surface analysis was carried out after the treatment using Auger electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS). The treatment conditions greatly affected the spreading angle and joint strength. The addition of O_2 and H_2 gases to N_2 gas was effective to improve the wettability of the Au-finished substrate and the bondability between the Au bump and substrate, respectively. The spreading angle rapidly decreased with increasing treatment time from 0.3 to 1 s and then decreased slightly with further increase in the treatment time, whereas the bonding strength peaked after the treatment for 0.5 to 2s and then decreased.