International Business Machines Corporation
Embedded Metal Contamination Removal from BEOL Wafers

Abstract:

A novel bevel etch sequence for embedded metal contamination removal from BEOL wafers is provided. In one aspect, a method of processing a wafer includes: performing a bevel dry etch to break up layers of contaminants with embedded metals which, post back-end-of line metallization, are deposited on a bevel of the wafer, which forms a damaged layer on surfaces of the wafer; and then performing a sequence of wet etches, following the bevel dry etch, to render the bevel of the wafer substantially free of contaminants, wherein the sequence of wet etches includes etching the damaged layer to undercut and lift-off any remaining contaminants. A wafer, processed in this manner, having a bevel that is substantially free of contaminants is also provided.