Photoreactive Chemisorbed Monolayer Suppressing Polymer Dewetting in Thermal Nanoimprint Lithography

Abstract

We describe reactive-monolayer-assisted thermal nanoimprint lithography. The reactive monolayer inducing the graft reaction with thermoplastic poly(styrene) by ultraviolet light exposure was formed from 4-((10-mercaptodecyl)oxy)benzophenone on a gold thin film. The photochemical graft reaction suppressed the thermally induced dewetting of a poly(styrene) thin film on the modified gold surface. As a result, the poly(styrene) thin film used as a resist layer for wet etching could be patterned by thermal nanoimprint lithography, and 100-nm-scale patterns of a gold thin film could be prepared simply by wet etching.

Reactive-monolayer-assisted Thermal Nanoimprint Lithography with a Benzophenone-containing Trimethoxysilane Derivative for patterning Thin Chromium and Copper Films

“…3(c). These results are in good agreement with those observed for Au substrates [6], indicating clearly that TMPBP works as an ultrathin binder to anchor PS molecules to the surface of the Cr-plated substrate.…”

“…After the UV exposure, the PS was annealed above a glass transition temperature of PS (105 °C) for 2 min to evaporate solvent toluene. Thermal processing of the thin PS film was carried out using the silicon mold in a manner similar to a thin PS film on a modified Au-plated substrate [6]. The R-TNIL, as shown in Fig.…”

Reactive-monolayer-assisted Thermal Nanoimprint Lithography

“…A Ag/PEN sheet having a Ag layer of 0.12 m in thickness on a poly(ethylene naphthalate) film was used for a substrate, and a benzophenone-containing PrM was formed on the Ag layer as shown previously [5]. A fluorescent dye-doped PS resist layer was prepared by spin coating for resist pattern inspection [21].…”

“…We demonstrated reactive-monolayer-assisted thermal nanoimprint lithography (R-TNIL) as an advanced TNIL technique [5,6]. In R-TNIL, a surface of a metal-plated substrate is modified with a photoreactive monolayer (PrM) having a benzophenone moiety and then a resist layer of thermoplastic polymer polystyrene (PS).…”

“…Improvement of lateral resolutions of patterned resist and metal layers by dewetting suppression Oda et al first reported that suppression of thermally induced dewetting of a PS resist layer could be caused by exposure of the PS resist layer on a PrM-modified Au-plated substrate to UV light as a result of a photochemical graft reaction [5,7]. The PrM is formed from 4-[(10-mercaptodecyl)oxy]-benzophenone by immersion of Au-plated substrates in its ethanol solution.…”