Bilayer Resist Method for Room-Temperature Nanoimprint Lithography

Abstract

A compact nanoimprint lithography (NIL) apparatus using the driving power of a servomotor has been newly developed. A bilayer resist method using hydrogen silsequioxane (HSQ) as a top layer and AZ photoresist as a bottom layer has been proposed to achieve high-aspect resist patterns on a nonflat surface for room-temperature nanoimprint lithography (RT-NIL). The etching rate ratio of HSQ to AZ photoresist was higher than 100 for O2 reactive ion etching (RIE), indicating that the HSQ top layer has sufficient etching tolerance. We have achieved the high-aspect nanostructure patterns of 100-nm-linewidth and 1-µm-height using the NIL apparatus developed here.

Electron-beam exposure mechanisms in hydrogen silsesquioxane investigated by vibrational spectroscopy and in situ electron-beam-induced desorption

“…Albrecht and Blanchette's thermal desorption data from HSQ above 410°C, which showed H 2 being produced at two orders of magnitude higher than SiH 4 and was attributed to reaction mechanism (7).…”

“…While its first resist applications were with electron beam systems, 1 HSQ has been successfully applied to both EUV 2 and nanoimprint lithographic applications as well. [3][4] Using electron-beam lithography (EBL), 11-nm half-pitch gratings in 70-nm-thick films 5 and sub-10 nm half-pitch gratings in 30-nm-thick films 6 have been fabricated using HSQ, making it one of the highest-resolution electron resists available. Furthermore, compared to carbon-based highresolution resists, HSQ's SiO 2 -like composition results in a significantly higher modulus and less resist collapse, a plaguing issues for dense, high resolution features.…”

“…This SiO 2 -like composition also results in excellent pattern-transfer selectivity to a variety of materials. [4][5]7 The fully-condensed HSQ structure has the formula (HSiO 3/2 ) n . [8][9] For n = 8, the proposed structure of HSQ is cubic, with silicon and hydrogen atoms at the vertices and oxygen atoms forming the edges.…”

Scanning x-ray microscopy investigations into the electron-beam exposure mechanism of hydrogen silsesquioxane resists

“…7,8 HSQ is attractive as a resist for a variety of reasons including demonstrated high-resolution down to 12.5 nm half-pitch gratings 5 with a sensitivity comparable to Zeon corporation's ZEP-520 or polymethyl methacralate (PMMA). In addition HSQ exhibits excellent dry etch pattern transfer characteristics, especially for bi-layer applications using oxygen plasma chemistry, 5,8,9 because it undergoes further curing in that environment. 10 HSQ was initially studied and marketed by Dow Corning as a spin-on Inter-Layer Dielectric (ILD) material, FOx®.…”

Surface Evaluation of HSQ Containing PDMS Additive after Room-temperature Nanoimprinting

“…However, a long EB exposure time is needed to make the HSQ pattern. Previously, we reported that the HSQ pattern can be obtained by room temperature (RT) nanoimprinting with a short fabrication time [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32] . In RT-nanoimprinting, the mold is pressed to a sol-gel material such as SOG without heating and UV irradiation processes.…”