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

We have evaluated both present and future G--and

A practical approach for submicron lithography is mix and match imaging using x -ray and optical steppers. The advantages of x -ray lithography are primarily submicron resolution, unlimited depth of focus and insensitivity to substrate topology and composition. Optical lithography on the other hand becomes most difficult in the submicron region where process latitude becomes tightly limited.

This paper examines the performance of a specific family of dyed resists. The effect of dye concentration on the line profiles of a homologous series of positive photoresists is studied. Usable images are obtained with dye concentrations of 0 %, 0.4 %, and 0.6% (percentage of the formulation). Both standard softbake or a softbake plus post-exposure bake (PEB) processes are used. Resist linewidths and cross -sections are measured on substrates that are representative of those encountered on integrated circuits. Optical exposure and develop simulation parameters (two developers) for this family of resists are also extracted.

An electron beam metrology system has been used to study optical proximity effects in contrast -enhanced lithography. In this case, precision and differential measurement capability were found to be more important than absolute accuracy.Our results show distinct proximity effects due to retarded bleaching of the contrast enhancement layer over the smaller features and some additional anomalous effects which have been attributed to subtle changes in edge morphology.SEM micrographs of line-and -space patterns revealed sloped profiles at the smallest geometries near the Rayleigh limit of the exposure tool.Intermediate geometries had vertical profiles, and larger ones were reentrant.