Young-Suk Sim

UV-nanoimprint lithography using a diamond-like carbon stamp

Two-dimensional (2-D) and three-dimensional (3-D) diamond-like carbon (DLC) stamps for ultraviolet nanoimprint lithography (UV-NIL) were fabricated with two methods: namely, two-photon polymerization (TPP) patterning, followed by nanoscale-thick DLC coating; and a fluorine-doped (F-DLC) coating process, followed by O2 plasma etching. The DLC layer on top of polymer pattern or flat quartz substrate was formed using radio frequency plasma enhanced chemical vapor deposition (RF-PECVD) process or Direct current (DC) and radio frequency (RF) magnetron sputtering process. It was also demonstrated that the DLC stamp with no anti-adhesion layer could be used for imprinting wafers on UV-NIL and the dimensions of the stamps features correlated well with the corresponding imprinted features.

Analysis of Nonniformity of Residual Layer Thickness on UV-Nanoimprint Using an EPS(Elementwise Patterned Stamp)

Imprint lithography is a promising method for high-resolution and high-throughput lithography using low-cost equipment. In particular, ultraviolet-nanoimprint lithography (UV-NIL) is applicable to large area imprint easily. We have proposed a new UV-NIL process using an elementwise patterned stamp (EPS), which consists of a number of elements, each of which is separated by channel. Experiments on UV-NIL are performed on an EVG620-NIL using the EPS with 3mm channel width. The replication of uniform sub 70 nm lines using the EPS is demonstrated. We investigate the nonuniformity of residual layer caused by wafer deformation in experiment with varying wafer thickness. Severely deformed wafer works as an obstacle in spreading of dropped resin, which causes nonuniformity of thickness of residual layer. Numerical simulations are conducted to analyze aforementioned phenomenon. Wafer deformation in the process is simulated by using a simplified model, which is a good agreement with experiments.

Step and repeat UV-nanoimprint lithography using a large area stamp

Ultraviolet-nanoimprint lithography (UV-NIL) is a promising method for cost-effectively defining nanoscale structures at room temperature and low pressure. To apply a large-area stamp to step-and-repeat UV-NIL in an atmospheric environment for high-throughput, we proposed a new step-and-repeat UV-NIL process using an elementwise patterned stamp (EPS), which consists of elements separated by channels. The proposed UV-NIL is able to imprint an 8-in. wafer with a 5 sq. in EPS in four times. 50 - 80 nm features of the EPS were successfully transferred over 8-in. wafers. The experiments demonstrated that a large-area EPS in the step-and-repeat UV-NIL can be used for imprinting 8-in. wafers in an atmospheric environment.