Etch rate enhancement of photoresist in nitrogen-containing plasmas

Abstract

It is shown that the etch rate of photoresist can be greatly enhanced by adding 1% of nitrogen into the oxygen plasma. An increase in the atomic oxygen concentration is shown to be responsible for this enhancement in the etch rate. A further enhancement in the etch rate is obtained by introducing CF4 into the O2 -N2 plasma. The enhancement in the etch rate of photoresist in the CF4 -N2 -O2 mixture is the result of an increase in the atomic concentrations of oxygen and fluorine in the plasma.