Influence of vapor phase pre-oxide-cleaning on the oxidation characteristics

Abstract In this paper the oxide growth with and without annealing in nitric oxide (NO) is investigated for different types of pre-oxidation cleaning. Two types of vapor phase cleaning (VPC), so called VPC1 and VPC2, are investigated and compared to standard wet cleaning. The VPC1 cleaning uses anhydrous HF (AHF)/methanol for the removal of the native oxide. The VPC2 cleaning is similar to the VPC1 with an additional ozone cleaning step after the native oxide removal. The oxidation rate in a RTO module, which is integrated in the same cluster tool increases for integrated pre-oxidation cleaning (VPC) compared to the standard wet cleaning. These results correlate to the increase in fluorine content in the oxide using the VPC pre-oxidation cleaning. The NO annealed oxides show a more significant increase in oxidation rate using the VPC2 cleaning type, which has an ozone step after the native oxide removal. This seems also to be correlated to the difference in fluorine content.