High Dose Implant Stripping
Specialized processes have been developed for high dose implant stripping (HDIS) because of the difficulty in removing the highly cross-linked and carbonized photoresist crust. Traditional plasma followed by wet processing has limitation due to the silicon loss, and all-wet processing has limitations due to the implant dose and energy creating a damaged crust layer that cannot easily be removed with standard processing chemicals. This chapter discusses the definition of high-dose implant, the formation of the crust, the methods to remove the crust and the bulk photoresist, the limitations of the processes plus newly developed methods to address these limitations.
Keywords: high-dose implant stripping, photoresist stripping, sulfuric acid hydrogen peroxide mixture, hydrogen plasma, photoresist crust, silicon loss, junction loss
8.1 Introduction and Overview of High Dose Implant Stripping
Post-ion implant photoresist is challenging to completely remove due to the high doses of the ions that are implanted into the photoresist because the photoresist is cross-linked and dehydrated during the process. Plasma stripping followed by a wet cleaning process, typically SPM (sulfuric acid hydrogen peroxide mixture) sometimes followed by SC-1 (standard clean-1), is the process of record at ...