Nanoimprint stamp fabrication by combination of T-SPL and dry etching

Fabricating high-resolution grayscale patterns at the nanoscale remains a significant challenge, particularly on fused silica substrates. These grayscale patterns find extensive applications in optical devices such as optical gratings, diffraction optics, and transparent electronics in the semiconductor industry. Although thermal scanning probe lithography (T-SPL) enables high-resolution grayscale patterning on polyphthalaldehyde (PPA), it is a slow process and necessitates also transfer to a stable substrate. This limitations can be overcome by combining it with reactive ion etching (RIE) and nanoimprint lithography (NIL) to enhance throughput. Recent studies have focused on amplifying grayscale patterns using reactive ion etching and achieving smooth surfaces through these methods combined with ion beam etching. In line with this research, our project aimed to fabricate a nanoimprint stamp with grayscale patterns for subsequent transfer through nanoimprint lithography, while keeping roughness below one nanometer.