Elucidation of an isopropyl alcohol (IPA) adsorption phenomenon on a wafer surface for achieving an ultra-clean and IPA-saving drying process in the batch cleaning system

摘要

Displacing the water remaining on a wafer surface by using condensed IPA improves the effectiveness of IPA-based drying techniques. Although this drying technology has been used for years, recent device technologies have needed extremely high-performance drying processes. We characterized an IPA adsorption phenomenon on a wafer surface by using the batch cleaning system and determined the appropriate drying conditions. Our results revealed that the IPA supply rate had a great influence on watermark formation. This can be prevented by increasing the IPA supply rate because the rapid increase of IPA concentration in the remaining water on wafer surface suppresses the dissolution of silicon into water. Through both understanding of an IPA adsorption on a wafer surface and control of the drying condition, an ultra-clean and IPA-saving drying process with a watermark-free performance for future device technologies can be achieved.