Nanoimprint resist

With such a UV-curable nanoimprint resist, both micro- and nanoscale patterns can be easily achieved at room temperature and at a pressure of less than 0.1 MPa by using a conventional contact exposure tool. In Fig. 7A, recessed hole pattern of 20 pm in diameter and protruded pillar pattern of 1 pm in diameter... 

One example of UV nanoimprint resists is shown in Figure 4.9. The resin contains three kinds of acryl monomers t-butylacrylate, ethylene glycoldiac-rylate, and (3-acryloxypropyltristrimethylsiloxy)silane. The resist also contains a photoinitiator, 2-hydroxy-2-methyl-l-phenylpropane-l-on. The resin... 

One example of commercial UV nanoimprint resists is shown in Table 4.1. Since the resist is of a liquid form, spin coating can be applied for forming the layer. An imprint is performed under room temperature at low imprint pressure (>100 mbar) in vacuum (or atmospheric pressure). UV light is exposed by an i-line lamp. 

The principle of nanoimprint is quite simple. As shown in Fig. lA, NIL uses a hard mold that contains nanoscale features defined on its surface to emboss into polymer material cast on the wafer substrate under controlled temperature and pressure, thereby creating thickness contrast in the polymer material, which can be further transferred through the resist layer via an O2 plasma-based anisotropic etching process. Nanoimprint has the capability of patterning sub-10 nm features, " yet only entails simple equipment setup and easy processing. This is the key reason that NIL attracted wide attention within only a few years after its inception. 

DEVELOPING BETTER RESIST MATERIALS FOR NANOIMPRINT LITHOGRAPHY... 

Nanoimprint lithography Molding of pattern Parallel, fast, no resist, solvents, etc. Large structures, residual chemicals Smaller structures, improved pattern transfer... 

FIGURE 5.5.32 Schematic of nanoimprint hthography (NIL). (1) A rigid mold is pressed into a thermoplastic resist, heated above its glass transition temperature, to create an imprint. (2) The mold is removed, leaving behind the patterned resist. (3) An anisotropic etch removes the residual resist and transfers the pattern into the substrate. (From S. Y. Chou et al., J. Vac. Sci. Technol, B, 14, 4129, 1996.)... 

Ishii, Y. and J. Taniguchi. 2007. Fabrication of three-dimensional nanoimprint mold using inoiganic resist in low accelerating voltage electron beam lithography. Microelectronic Engineering 84 912-915. 

Nanoimprint lithography (NIL) is a relatively new technique designed to produce precisely defined nanoscale features in a parallel, efficient, and cost-effective manner [3,4]. In a typical NIL process, a prepatterned mold is used to press against a resist layer which can go through a thermal plastic transition at an elevated temperature or can be permanently... 

A novel liquid thermal polymerization resist is reported to be a superior polymer for thermal nanoimprint. The resist is a mixture of polymethylmethacrylate (PMMA), methylmethacrylate (MMA), n-butylacrylate (n-BA), methacrylic acid (MAA), and 2,2-azobisisobutylnitrile (AIBN). The resist can be imprinted at room temperature with a pressure of 1.2 MPa, and then cured at 95°C to obtain nanoscaled and microscaled patterns. Replications... 

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