Effects of Plasticizing Additives on Performance of 193 nm Chemically Amplified Positive Resists

摘要

The effects of plasticizing additives on lithographic performance. PEE temperaturt dependence. and environmental stability were investigated in 193 nm chemically amplifiec resists based on norbornene t-butyl ester/maleic anhydride copolymer. Tert-butyl (t-Eu cholate was used as a plasticizing additive to control the glass transition temperatures (Tg of the resists. The resist softening temperature was decreased from > 180 °C to 1 So °C b~ the addition of t-Eu cholate. The resist sensitivity and resolution were almost unchanged when post-exposure bake (PEE) temperatures were below the resist softening temperature The resolution capability was degraded as the PEE temperature increased to above th, resist softening temperature. High environmental stability of 60 min was achieved b. optimizing the resist softening temperature. because soft baking at around the resis softening temperature reduced the amount of residual solvent. and thus made the resis absorb basic airborne contaminants less readily. However. the environmental stability wa deteriorated at lower PEE temperature. Strict optimization of the PEE temperature i required. for both the resolution capability and environmental stability. The environmentl stability of the optimized resist at adequate PEE temperature was almost the same as thl of248 nm acetal type resist, and it was sufficient for practical use.