Effect of plasma cleaning process in the wettability of flip chip PBGA substrate of integrated circuit packages

Abstract

This study investigated the plasma cleaning effect on two different commercially available packaging substrates used in the flip chip PBGA substrates for integrated circuit packaging. Investigation and related evaluation have been carried out to determine the wettability of the substrate surface. Contact angles on each substrate are measured by observing the spreading area of the water droplets that referred to the surface tension of the droplets towards the substrate surface. Further investigation has also been conducted by applying plasma cleaning and prebake process before and after flux reflow process together with the staging process. Moreover, substrates are subjected to prebake process followed by plasma cleaning and vice versa. Investigated result shows that plasma cleaning at later time has shown significant improvement (a quantitative 70% decrease in contact angle) in achieving better wettability of the solder bumps on packaging substrates. © 2010 Asian Network for Scientific Information.