Submicron resolution photolithography by spectral shaping

A novel exposure technique based on spectral shaping over a narrow exposure band (305-335 nm) has been used to achieve resolution comparable to the exposing wavelength in positive photoresist. Two hundred arrays of comb meander patterns with linewidths as small as 0.20 µm, and 3 cm in length were vacuum contact printed in AZ2415 resist on 50 mm diameter oxidized silicon substrates. The average standard deviation of linewidth variations is only 300 Å and resist pattern cross-sections show vertical edge profiles with aspect ratios of 2:1 or better.