Neutral-Beam-Assisted Etching of SiO2–A Charge-Free Etching Process–

Highly directional and low-damage dry etching of SiO2 is realized by neutral-beam-assisted etching reactions. In this etching, low-energy neutral beams and neutral radicals are simultaneously supplied to the specimen, and the etching reactions are enhanced by the neutral beam bombardment. Low-energy (500 eV or less) Ar° neutral beams are generated from Ar+ ion beams by charge exchange reactions. Neutral radicals are generated in a microwave plasma of CHF3. The specimen surface is subjected only to these electrically neutral particles by eliminating charged particles with the retarding grids. The neutral-beam-assisted etching enables deep submicron pattern delineation without any serious radiation damage such as dielectric breakdown. It is a promising substitute for the current plasma etching as a future low-damage etching process.