SBIR/STTR Phase I: Environmentally Benign, High-Pressure Plasma Cleaning Tool for Photoresists

This Small Business Innovation Research (SBIR) Phase I project will establish the performance of the Plasma Flow Source for stripping and residue cleaning of photoresists on 200 mm semiconductor wafers without producing any environmentally-damaging waste streams. In particular, it will determine the effect of process conditions and gas chemistry on stripping rate and uniformity. Measurements will be performed on standard and heavily implanted photoresists as well as on patterned wafers following reactive ion etching. The novel Plasma Flow Source system produces a large flux of oxygen atoms at low-temperatures and pressures between 10 and 1000 Torr. It has been shown that this source strips photoresists from 100 mm wafers at rates of up to 0.9micron/min at 120 C and 3.0 micron/min at 250 C, with excellent uniformity. The high ash rate observed at 120 C shows promise for removing heavily implanted resists and hardened residues from reactive ion etched substrates. Moreover, operation at higher pressure reduces gas consumption and dramatically decreases pumping requirements. The knowledge gained from this study will establish the potential of this exciting new technology for environmentally-benign, photoresist stripping of wafers for next-generation semiconductor devices.