Minimization of residual layer thickness by using the optimized dispensing method in S-FILTM process

Ultraviolet nanoimprint lithography (UV-NIL), which is performed at a low pressure and at room temperature, is known as a low-cost method for the fabrication of nano-scale patterns, and can fabricate patterns as small as 10 nm. In the patterning process, maintaining the uniformity of the residual layer is critical as the pattern transfer of features to the substrate must include the timed etch of the residual layer prior to the etching of the transfer layer. In pursuit of a thin and uniform residual layer thickness (RLT), we optimized a dispensing recipe of a drop-on-demand type for the IMPRIO100 manufactured by MII. For complete resin filling, resin droplets were placed on an effective area in such a way that the spacing between the droplets was narrow, using a zigzag-type array while not having a checkered pattern. Using a numerical iteration method, each initial volume and location of a droplet was calculated. The optimized dispensing recipe yielded a complete filling in the effective region and improved the uniformity, as shown with sub-40 nm RLT. A thin RLT with minimized deviation and a continual clearly defined edge of the imprint region were also successfully achieved.