Patent ID: 7501349

Claim:
A method for processing a substrate, comprising: providing the substrate in a process chamber, the substrate having an oxide layer formed thereon; and performing a sequential oxide removal process, comprising: exposing the substrate at a first substrate temperature that is less than or equal to 400° C. to a flow of a first etching gas comprising F 2 to partially remove the oxide layer from the substrate, raising the temperature of the substrate from the first substrate temperature to a second substrate temperature that is less than 900° C., and exposing the substrate at the second temperature to a flow of a second etching gas comprising H 2 to further remove the oxide layer and any F-containing impurities remaining on the substrate in a hydrogen anneal, wherein the flow of the first etching gas comprising F 2 , in addition to partially removing the oxide layer from the substrate, modifies the remaining oxide layer, thereby facilitating the further removal of the remaining oxide layer by the second etching gas comprising H 2 , and not F 2 .