A New and Innovative In situ Plasma Etch Pin-up Clean for Defect Reduction and Process Simplification

Removal of carbon-based polymer on the wafer edge bevel frontside and backside has attracted more attention in an attempt to reduce defects and improve yield. In this paper, we demonstrate a new and innovative plasma pin-up clean method to in situ remove polymers from both the wafer backside and the edge bevel areas. The results from real production wafers show the pin-up clean step can eliminate the carbon-based polymer at both frontside and backside of wafer bevel areas. This pin-up clean concept has been applied to multiple layers in various plasma etch tools for bevel dry etch step elimination and defect reduction with substantial yield improvement. We present the results of two cases that we apply the pin-up clean to remove flake defects and eliminate a down-stream bevel dry etch process step.