A Study of the Etching Characteristics of Semiconductor Materials in RF Plasmas.

An experimental study was made on the use of plasma etching machines to etch semiconductor materials used in microcircuit fabrication processes. Plasmas were used to etch a number of materials to include phosphosilicate glass, silicon nitride, chemically vapor deposited silicon dioxide, epitaxially deposited silicon dioxide, and silicon. Etching characteristics of these materials were obtained in a variety of operating conditions ranging from variations of power from 0 to 400 watts, pressure from 0 to 0.50 torr, and gas flow from 0 to 500 cc per minute. The etching technique was then used to etch circuit wafers which were developed into microcircuits. Results demonstrated that the plasma etching process could be used in place of chemical etchants. Yield of usable devices from the circuit wafers varied from 10 to 70 per wafer however, no damage was attributed to the plasma etching process. A limited investigation into the etching of multiple passivation layers was conducted but was not completed. Modified author abstract