Base additives for use in a single layer 193-nm resist based upon poly(norbornene/maleic anhydride/acrylic acid/ tert -butyl acrylate)

We report on a study of the chemical and lithographic behavior of two types of base additives. One class of materials that we will report on are aminosulfonate onium salts, we report a study of both the thermal stability and the lithographic behavior imparted by these as a function of chemical structure. It will be shown that the decomposition temperature is a function of the basicity (nucleophilicity) of the counter anion but this can be countered by appropriate choice on onium cation. We will also discuss the lithographic performance of formulations containing transparent ammonium carboxylate bases. It will be shown that these materials provide for comparable lithographic to a standard formulation containing an amine additive. Since carboxylates and aminosulfonates are far less nucleophilic than amine additives these additives may be useful because they will not have the tendency to interact with electrophilic sites such as maleic anhydride derived repeat units.