By Scott D. Szymanski, March Plasma Systems
Introduction
Commercially available plasma treatment systems can be used for a variety of wafer-level packaging (WLP) process steps including removal of photoresist residue after development (i.e. descum); organic, metal, and oxide contamination removal; wafer surface cleaning and roughening; chemical bond activation at the wafer surface to improve bondability; and increasing wettability and uniformity of liquid flow over the wafer surface. Through various alterations to the plasma chemistry