Single Backside Cleaning on Silicon, Silicon Nitride and Silicon Oxide

Abstract

In this study, we used an SEZ single-wafer spin-processor to develop a single backside cleaning solution able to remove any metallic or exotic contaminants by etching a few angstroms of the wafer backside, whatever its coating (no coating, Si3N4 or SiO2). An H2O:H2O2:H2SO4:HF mixture was selected because it allowed independent control of the etch rate on the 3 materials of interest, without roughening to much the silicon surface. Chemistry efficiency was then checked on wafers intentionally contaminated with various metals, and on “production wafers” contaminated during exotic materials deposition or classical copper processes.