Acid diffusion characteristics of RELACS coating for 193-nm lithography

So far, there are still many unknown phenomena on the interface of RELACS/resist during mixing bake (MB) processing. Knowing the precise quantitative interaction of these phenomena is significantly important to understand RELACS coating in order to attain much finer contacts as well as spaces with conventional optical lithography. Furthermore, more clear understanding of acid diffusion about RELACS/resist provides us more explicit design concept to increase the shrinkage of RELACS coating for 193nm lithography. In this study, we studied the differences of acid diffusion characteristics between 248nm and 193nm chemically amplified resists with various thermal acid generators (TAGs) in aqueous polymer coating. The diffusion phenomenon from resist to aqueous polymer coating is strongly correlated to the intrinsic diffusion characteristics of both resists. This study also revealed that the quantitative structure properties of organosulfonic acids generated from TAGs affects on the diffusion phenomena from resist to RELACS coating.