Process control for nanoimprint lithography

To tackle the demoulding and conglutinating problem with the resist and hard mold in the nanoimprint lithography process, a soft mould can be used to demould and reduce the macro or micro mismatch between mould bottom surface and wafer top surface. In nanoimprint lithography process, a mathematical equation is formulated to demonstrate the relation between the residual resist thickness and the pressing force during pressing the mould toward the resist-coated wafer. Based on these analytical studies, a new imprint process, which includes a pre-cure release of the pressing force, was proposed for the high-conformity transfer of nano-patterns from the mould to the wafer. The results of a series of imprint experiments showed that the proposed loading process could meet the requirements for the imprint of different patterns and feature sizes while maintaining a uniform residual resist and non-distorted transfer of nano-patterns from the mould to the resist-coated wafer.