Comparison of Standard Photoresist and Contrast‐Enhanced Photoresist Process Sensitivities

Abstract

Statistical experimental design techniques were used to make a systematic comparison between a standard photoresist process and a contrast-enhanced photoresist process. This approach allowed determination and comparison of process sensitivities and their dependence on process changes. The resist used in this study was HPR204 (Hunt), and the contrast-enhancement material was Altilith CEM 420 (General Electric). All substrates were exposed on a GCA 10X stepper with a 0.28NA, G-line lens. The results indicate that the contrast-enhanced process is less sensitive to focus and exposure dose variation, extends the effective working resolution of the exposure tool, and gives an increased sidewall angle in the final resist pattern, when compared to the standard resist process. However, the contrast-enhancement process examined, allows interfacial layer formation which results in an overhang, or lip, in the developed resist image.There are various methr :s available for the purpose of improving the performance of curreL optical liL.ography tools. These methods rely on innovative photoresist processing and/or new materials (1-6). Of the available options (including multilevel resist, dyed resist, antireflective coating, image reversal, and post exposure bake processes) the use of a contrast-enhancement mate-) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 130.216.129.208 Downloaded on 2015-03-11 to IP Vol. 134, No. 11 STANDARD AND CONTRAST-ENHANCED PHOTORESIST 2883 ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 130.216.129.208 Downloaded on 2015-03-11 to IP Vol. 134, No. 11 STANDARD AND CONTRAST-ENHANCED PHOTORESIST