Comparison of the lithographic properties of positive resists upon exposure to deep- and extreme-ultraviolet radiation

Nineteen chemically amplified ultrathin resists were imaged using exposure to extreme-ultraviolet (EUV) (13.4 nm) and deep-ultraviolet (DUV) (248 nm) radiation. Direct comparisons were made of photospeed, resolution, and line edge roughness (LER). The photospeed of these resists at 248 nm shows a good correlation with photospeed at EUV for three polymer types, but appears independent of photoacid generator type. This result underscores the importance of the polymer in photoacid generation at EUV. Resolution showed poor correlation between DUV and EW. Correlations were made between the line edge roughness of EW-imaged features and unexposed film thickness loss, resist contrast, image log slope (ILS), and LER of resists exposed at DUV. Both contrast and image log slope play important roles in defining LER performance-where the best LER is achieved at high contrast and high ILS. (C) 1999 American Vacuum Society. [S0734-211X(99)20306-X].