PROBLEMS AND SOLUTIONS FOR LOW-PRESSURE, HIGH-DENSITY, INDUCTIVELY-COUPLED PLASMA DRY ETCH APPLICATIONS

Dry etching for mainstream microelectronics applications has undergone a shift in the past few years towards high density plasma reactor des igns. Such sources operate at lower pressure which helps avoid undercu tting when etching small features (<0.6 mu m), however, new problems a lso arise, and in this paper a selection of these is aired. Results fr om the Electrotech Omega(R) 201 inductively coupled plasma etcher are used to reach the following conclusions: for production aluminium allo y etching, selectivity to photoresist can be significantly improved by use of HBr chemistry; for production dry develop of photoresist, an S O2-O-2 mixture can be used to give zero CD loss; and for copper etchin g, residue-free results are achieved on test wafers at a temperature o f >240 degrees C. (C) 1997 Elsevier Science S.A.