Study on Reduction of Substrates Dependency of Chemically Amplified Resist Jun-Sung Chun, Cheol-Kyu Bok, and Ki-Ho Baik Hyundai Electronics md. co., Ltd., Memory R&D Division San 136-1, Ami-ri, Bubal-eub, Ichon-si, Kyung-ki do, 467-701, Korea ABSTRACT In the case of silicon nitride films acid pretreatment can eliminate resist scum so that we can get clean resist profiles. The acid used, called Clean D treatment for photoresist strip, normally consists of a mixture of sulphuric acid(80% H20) and hydrogen peroxide(80% H20). ESCA(Electron Spectroscopy by Chemical Analysis) was used to examine the surface of the films after cleaning with acid and to monitor the change in atomic percents of the films with time. Considering all the analytical data, this acid treatment to silicon nitride makes the film surface oxide-rich resulting in forming barrier layer between substrates and protons from PAG(Photo Acid Generator). For BPSG(Boro-Phosphorous Silicate Glass) films the mechanism of the formation of resist foot is quite different from that of silicon nitride. Improved resist profiles on BPSG were obtained by the dehydration bake. Therefore it could be speculated that the formation of resist scums on silicon nitride films are due to the nitrogen in films and on the BPSG moisture. 02 plasma surface pretreatment was also reviewed. It is quite certain that these two methods, acid and 02 plasma treatments are very effective, economical and simple process. However, there are delay time effects after pretreating films unlike other conventional oxide capping layers. This problem will be also discussed in detail. Key words : Substrates dependency, Acid pretreatment, Resist scum, Dehydration bake, Silicon nitride, Plasma treatment, Oxide capping layer, Resist foot 1. INTRODUCTION Microlithography has been driven by the miniaturization of semiconductor devices. DRAMs are the driving forces of IC's development and are the technology indicator for advanced device manufacturing. DUV lithography such as KrF and ArF will be a product-worthy technology. For DUV lithography, KrF excimer laser source and chemically amplified resist has been developed for production. Much progress has been demonstrated in the field of transparent chemically amplified resists with high sensitivity and stability between exposure and post exposure bake. New DUV resists have been proven their potentials for feature sizes down to 200 nm lines/spaces patterns using high NA(O.6) without C. D variations after 6 hours delay time. However, for the implementation to the real devices, these new chemically amplified resists should be overcome the various substrate dependancy. Unlike conventional novolac based I-line resist, DUV chemically amplified photoresists produce protons during the exposure and catalyze photochemical reaction to delineate fine patterns. During PEB(Post Exposure Bake) the thermally activated protons diffuse into the exposed area. Due to its inherent instability protons 92 ISPIE Vol. 2724 O-8194-2100-6/96/$6.OO Downloaded From: http://spiedigitallibrary.org/ on 09/03/2014 Terms of Use: http://spiedl.org/terms