High selectivity BPSG to TEOS etchant

摘要

An organic acid/fluoride-containing solution etchant having high selectivity for BPSG to TEOS. In an exemplary situation, a TEOS layer may be used to prevent contamination of other components in a semiconductor device by the boron and phosphorous in a layer of BPSG deposited over the TEOS layer. The etchant of the present invention may be used to etch desired areas in the BPSG layer, wherein the high selectivity for BPSG to TEOS of etchant would result in the TEOS layer acting as an etch stop. A second etch with a known etchant may be utilized to etch the TEOS layer. The known etchant for the second etch can be less aggressive and, thus, not damage the components underlying the TEOS layer.