Polymer resist patterns without residual layers were formed on the Si substrate surface by photonanoimprinting using polydimethylsiloxane (PDMS) molds prepared from an ideally ordered anodic porous alumina template. In this process, the PDMS mold absorbs the thin photocurable monomer layer formed between the mold and substrate, thereby suppressing the formation of a residual layer. By applying Au electrodeposition to the obtained sample, we achieved selective deposition of Au in the openings of the resist pattern. After electrodeposition, the removal of the polymer resist using vacuum ultraviolet (VUV) light resulted in the formation of a Au thin film with a negative pattern of the polymer resist on the substrate. The obtained Au thin film acted as an etching mask during the chemical etching of the Si substrate. The etching pits formed on the Si substrate surface functioned as an antireflection structure, resulting in a lower surface reflectance of the obtained samples than that of a smooth substrate. Using this process, we can efficiently form resist patterns without residual layers. This resist formation method is expected to be useful for the fabrication of various electronic devices.
Yanagishita et al. (Wed,) studied this question.