Patent ID: 6143665
Filing Date: 2000-11-07
Classification: H01L

Abstract:
An improved method for etching oxide capable of preventing etching stop before the end of a plasma-enhanced etching operation, comprising the steps of:providing a substrate having an oxide layer formed thereon;performing a main etching operation to etch the oxide layer using a first mixture of etching gases of CHF.sub.3 /CF.sub.4 /Ar;performing a first cleaning operation to remove substantially most of a polymer by-product formed during the main etching operation using a mixture of cleaning gases, wherein the mixture of cleaning gases includes CF.sub.4 /Ar/N.sub.2 ;performing a first over-etching operation after the first cleaning operation to etch the oxide layer using a second mixture of etching gases, wherein the mixture of etching gases includes CF.sub.4 /C.sub.4 F.sub.8 /CO/Ar/N.sub.2 ;performing a second cleaning operation to remove substantially most of the polymer by-product formed during the first over-etching operation, wherein the mixture of cleaning gases in the first cleaning operation is used; andperforming a second over-etching operation to etch the oxide layer using the second mixture of etching gases as in the first over etching operation.