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Abstract

We evaluate a new photocurable imprint resist (mr-XNIL26) from Microresist Technology and develop a working photocurable nanoimprint process on various substrates using the Nanonex NX-2500 imprint tool. Summary of Research: Nanoimprint lithography (NIL) is an emerging technology that has the advantage of high throughput with sub-10 nm resolution. The resolution is largely governed by the feature dimensions of the master or template, which can be defined by advanced photolithography or electron beam lithography. NIL has been a strategic method on the ITRS roadmap for the 45 nm node and below. In addition to electronics, NIL can be a benefit to many applications including nanophotonics, biotechnology, displays, and microelectromechanical systems. The Nanonex NX-2500 has both thermal imprint (T-NIL) and photocurable imprint (P-NIL) capabilities. The photocurable imprint module uses 200W narrow band UV lamp. A quartz template was fabricated by sputter depositing a blanket layer of chrome in which a bright and dark field line space pattern was defined with the ASML DUV (248 nm) stepper producing a minimum feature size of 250 nm. The lithographically defined pattern was then transferred into the chrome using Cl2/ O2/Ar mixed chemistry in the Trion inductively coupled plasma (ICP) tool. This etch produces smooth and perfectly anisotropic sidewall profiles, which are essential for optimum imprint replication. The chrome is used as a hard mask to etch the quartz substrate to a depth slightly less than the mr-XNIL26 resist thickness in the Oxford 80 reactive ion etching (RIE) tool using CF4. The chrome is then removed by immersing the substrate in liquid chrome etchant. The template is coated with FOTS in the molecular vapor deposition (MVD) system to prevent the adherence of the resist in the imprint process. The Microresist Technology P-NIL resist system evaluated was mr-XNIL26, which is a new fluorine-modified UV nanoimprint resist with advanced release properties. We applied the mr-XNIL26-300 nm to a silicon wafer along with Omnicoat as an adhesion promoter, although the adhesion promoter is not necessary. The imprint is performed at room temperature and at a pressure of only 10 psi which is low compared to a thermal imprint process. The UV cure time is 30 seconds. The single layer P-NIL process is illustrated in Figure 1 adopted from Microresist Technology. Figure 1: mr-XNIL26 P-NIL process overview from Microresist Technology.