Further improvements in CGR formulation and process

In previous papers, we described initial evaluations of CGR 248 negative resist using a variety of exposure tools. During subsequent studies, the emphasis has been placed on optimizing material and process for Micrascan and Micrascan II pilot line and manufacturing operations. The formulation is based on polyhydroxystyrene (PHS), tetramethoxymethyl glycoluril, and a sulfonate ester of an N-hydroxy compound. We will discuss image stability as a function of delay time between post apply bake (PA) and expose and as a function of delay time between expose and the post expose bake (PEB). Further, data will show that immersion or puddle development provides a larger process window than spray development for features in the 0.30 to 0.35 micrometers range. The thermal stability of the imaged resist will be discussed as well as the shelf life which is at least 6 months at 23 degree(s) C. Finally, additional data is available concerning image uniformity and how print bias and etch bias contribute to the overall nested-isolated line offset for positive tone (APEX-M) and negative tone (CGR) resists. Data obtained from Micrascan II exposures with test reticles will demonstrate an acceptable process latitude for 0.30 and 0.35 micrometers features and a wafer to wafer image uniformity similar to that observed for APEX.