Photo-nanoimprint lithography combined with thermal treatment to improve resist pattern line-edge roughness

Abstract

We prepared a standard resist pattern to evaluate critical-dimension atomic-force microscopy (CD-AFM) by photo-nanoimprint lithography using a trilayer resist system. Standard patterns require low line-edge roughness (LER), which is an important factor in the accuracy of high-precision CD-AFM. However, LER can easily be increased during the dry etching necessary in the trilayer resist process. The LER of final standard patterns was 2.5 nm (1 sigma), which was made using a mould of which the LER is 2.2 nm. We thermally treated the standard resist patterns to reduce the LER; the LER improved from 2.5 to 1.2 nm with the thermal treatment.

A poly(dimethylsiloxane)-coated flexible mold for nanoimprint lithography

“…Since the advent of NIL [4,[16][17][18][19][20][21][22][23][24][25][26][27][28] in the early 1990s, a facile and parallel patterning of various nanostructures has been realized, dispensing with the use of complicated and expensive optical devices. Despite these advantages, the molds are prone to fracture because they are fabricated using hard substrates such as Si/SiO 2 [16][17][18][19][20]29] and quartz [4,[21][22][23][24][25].…”

“…Since the advent of NIL [4,[16][17][18][19][20][21][22][23][24][25][26][27][28] in the early 1990s, a facile and parallel patterning of various nanostructures has been realized, dispensing with the use of complicated and expensive optical devices. Despite these advantages, the molds are prone to fracture because they are fabricated using hard substrates such as Si/SiO 2 [16][17][18][19][20]29] and quartz [4,[21][22][23][24][25]. Also, thermoplastic polymers such as polymethylmethacrylate (PMMA) [16-20, 30, 31], polystyrene (PS) [31][32][33][34], and polycarbonate (PC) [31], used as resists, require high pressure (40-130 bar) [20] and high temperature (140-180 • C) [20] for the polymer to fill the grooves of the protrusions on the mold surface.…”

Thermal development of a calixarene resist

“…1 Thermal development is a relatively low temperature process, typically requiring temperatures in the 100-300°C range. 6 Fully developed submicrometer structures were made using UV and electron beam exposures of poly͑4-chlorophthalaldehyde͒. 2,3 In these studies thermal development was also shown to improve resist sensitivity and no resist flow was observed.…”