Nanoimprint and Lift-Off Process Using Poly(vinyl alcohol)

Abstract

We developed a lift-off process for a nanoimprint lithography (NIL) using poly(vinyl alcohol) (PVA) as the replicated material. PVA could easily be dissolved in water. A conventional lift-off process using poly(metyl methacrylate) (PMMA) uses acetone as a solvent, while the lift-off process using PVA uses water as a solvent, which is an ecologically friendly process. We demonstrated Au patterns with sub-µm dimensions using a lift-off process with a PVA single layer. In addition, an Hydrogen silsesquioxane (HSQ)/PVA bilayer structure was used for the lift-off process. This bilayer structure could be fabricated by room-temperature NIL and dry etching. Au patterns were easily obtained using the bilayer structure having an inverse tapered shape. In the lift-off process without using HSQ/PVA bilayer, Au wiring with sub-µm linewidth could be obtained, however, 100-nm-linewidth patterns did not remained. Line-and-spacing gratings of 100 nm in the Au patterns were demonstrated using the water lift-off process with the HSQ/PVA bilayer structure.

A water-processable cellulose-based resist for advanced nanofabrication

“…PVA is frequently used only as a lift-off layer since nanoimprinting this material requires the use of hard molds under high pressures (5 MPa), which hinder conformal contact with the substrate. 13 In contrast, we demonstrate herein the imprinting of HPC with extremely low pressures ( ca. 0.05 MPa) and flexible PDMS molds.…”

Lift-off process using bilayer ultraviolet nanoimprint lithography and methacryloxypropyl-terminated-polydimethylsiloxane-based imprint resin

“…The composition of the imprint resin is 94 wt % of M-PDMS ͑Gelest͒ as a base resin, 3 wt % of UV initiator ͑IGAcure184™, Ciba-Geigy͒, and 3 wt % of methacryl-oxypropyl-trichlorosilane ͑Gelest͒, 14 which can bond to hydroxyl groups on the PVA underlayer to improve adhesion between the resin and substrate. 16 Figure 3 shows scanning electron microscopy ͑SEM͒ images of patterns of the quartz master template used in this experiment ͓Figs. The quartz master template used in this experiment was fabricated by conventional deep-UV photolithography and RIE with CHF 3 gasbased plasma.…”

Fabrication of Self-standing Polystyrene Thin Films with Fine Through Holes by use of Water Soluble Resin Sacrificial Layer

“…Since PVA is water soluble resin, this film can be easily removed in water without film damage for various resins. By use of this unique property, PVA is often used as the sacrificial film [17][18][19][20]. For PVA/PET sheet, the PVA film has enough thickness, and the film can work as supporting film for the thin patterned resin.…”