Plasma Etching Process Induced Closed-loop Metal Pattern Damage

A new type of plasma process induced closed-loop metal interconnect damages were observed on the 0.5/spl mu/ SRAM production wafers after metal etching processing. The poor heat dissipation and the local plasma non-uniform within the closed-loop area had been identified to be the root causes. The degree of plasma process induced metal damage can be improved by reducing the wafer surface temperature and the magnetic field in the reactive plasma.