The effect of photoacid generator structure on deep ultraviolet resist performance

The structural influence of photoacid generators on deep ultraviolet resist performance is investigated in both high and low activation energy resist systems. The lithographic behavior of the photoacid generator is considered in terms of the structure of the photogenerated acid and the light sensitive chromophore. First, the lithographic impact of the photogenerated acid is investigated in terms of acid strength and acid size in resists optimized for high and low temperature processing, respectively. Dissolution kinetics, contrast curve data, and absorbance data are presented for a series of high and low activation energy resists in which the structure of the photogenerated acid is systematically varied. The results of these studies are discussed in terms of the photogenerated acid, emphasizing the impact of acid strength and size on lithographic performance and resist dissolution rate kinetics for each resist platform. Second, the structural influence of the light sensitive photoacid generator (PAG) chromophore is investigated by comparing the lithographic performance and acid generating efficiency of iodonium and sulfonium salt PAGs. Last, correlations of lithographic performance and dissolution rate kinetics are probed in terms of resist type (high and low temperature systems) and PAG structure.