A SOURCE OF HYPERTHERMAL NEUTRALS FOR MATERIALS PROCESSING

In this letter, we describe a unique method of producing hyperthermal neutrals for material processing. The hyperthermal neutrals are produc ed by accelerating inns across a sheath from a plasma onto a surface, On impact, the ions are neutralized and reflected with similar to 50% of their incident energy, These neutrals then bounce off of additional surfaces prior to impacting the target, This unique multiple bounce s ystem was developed for the following reasons: to reduce contamination from sputtered surface material, improve beam uniformity, and reduce UV radiation in the hc atn path. As a test of this method, we built a prototype beam source and used it to ash photoresist at rates up to 0. 022 mu m/min. These rates are consistent with a predicted neutral beam flux, 2 x 10(14) cm(-2) s(-1). In addition, a simple model is used to indicate that this method is capable of producing economically accept able ash rates. Comparisons with other neutral-beam production methods are made. (C) 1997 American Institute of Physics.