Five-step loading locus for high-conformity patterning in nanoimprint lithography

In the nanoimprint lithography process, a mathematical equation is formulated to demonstrate the relationship of the residual resist thickness and the pressing force during pressing the template toward the resist-coated wafer. Associated with ultraviolet-curing characteristics of the liquid polymer resist, the relationship between the curing depth of resist and ultraviolet exposure is also established. Based on these analytical investigations, a five-step loading locus, which includes a pre-cure release of the pressing force, is proposed for the high-conformity transfer of nano-patterns from the template to the wafer. It is experimentally shown that this loading process can effectively reduce the residual resist thickness while maintaining a uniform residual resist and non-distorted transfer of nano-patterns to the resist-coated wafer, and a high-conformity of 100 nm feature can be achieved.