Defects Elimination for ArF Implant Lithography

Abstract

The application of ArF photoresist for implant process poses big challenge for process qualification in terms of defects control. Resist cracks and post development resist residues are the two most evident defects. In this study, two ArF photoresists for implant process have been selected to investigate the defect elimination. Lower PEB (post exposure bake) temperatures could help to reduce the tensile stress accumulated in the resist thus lower the risk of resist cracks. To reduce resist residue defect, longer deionized (DI) water rinse should combine with special puddle steps to relieve the developer pH shock during developing process. For better understanding the relationship between crack defects and contact angle, one advanced adhesion promotion material was introduced and investigated. It was found the spin-coated adhesion promotion material can significantly enhance the adhesion between the resist film and the underlying substrate due to lower contact angle formed. The implementation of the advanced adhesion promotion material resolved the resist cracks issue successfully. Finally, defects free ArF implant process was achieved through process optimization in our study. 