Patent ID: 6358859
Filing Date: 2002-03-19
Classification: H01L

Abstract:
A method for etching a trench in a silicon wafer comprising:(a) providing a silicon wafer; (b) forming a hardmask defining a trench on said wafer; (c) providing an etching tool having an etching chamber, a transfer chamber, and a load lock; (d) loading said wafer into said etching chamber; (e) etching said trench in said wafer with a plasma formed in a first gas flow containing a halogen species whereby a chemisorbed halogen layer forms on surface regions of said wafer; (f) purging said etchant gas from said etch chamber with a neutral gas; (g) after step (f) and without breaking vacuum, transferring said wafer from said etching chamber into evacuated said transfer chamber; (h) subjecting said wafer to a second flow of a carrier gas containing water for a time period whereby said chemisorbed halogen layer is discharged from said surface regions and purged from said transfer chamber; (i) evacuating said transfer chamber; (j) after step (i) and without breaking vacuum, transferring said wafer from said transfer chamber into said load lock; and (k) unloading said wafer from said etching tool.