Evaluation of a new environmentally stable positive tone chemically amplified deep-UV resist

Similar to most of the reported positive deep-UV resists, this new resist is also a chemically amplified system. However, unlike other resists, this resist if resilient to airborne base contaminants and it shows stable resist linewidth with more than 24 hours delay between exposure and develop. This resist has high sensitivity (17-18 mJ/cm2), high contrast (7), high resolution (0.35 micrometers with (lambda) equals 248 nm and NA equals 0.37) and large process latitude in deep UV-lithography. This system does not require postexposure bake. When a postexposure bake is introduced, the linewidth variation is in the range of 2-3 nm per degree. This eliminates the concern of linewidth variation in resist images due to slight variation of postexposure baking temperature, which is commonly encountered in chemically amplified resist systems. This resist system is environmentally stable like conventional DQ system; at the same time, it retains most of the merits of chemically amplified system.