Near-field optical photolithography for high-aspect-ratio patterning using bilayer resist

We attempted to achieve a sufficiently large high-aspect-ratio patterning in near-field optical photolithography employing a bilayer resist process. In this experiment, we formed a resist pattern with a linewidth of 130 nm and a depth of 550 nm . This suggests that a practical method of near-field optical photolithography should become available. We also studied the dependency of an optical pattern on resist film thickness by the three-dimentional finite-difference time-domain method. The calculation results suggest that the resist film thickness affects the distribution of light in the resist.