Research On Principle And Process Control Of Nanoimprint Lithography

The thesis presents the principle and experimental study of nanoimprint lithography. The primary objective is to investigate the application of nanoimprint lithography in three-dimensional micro-structure fabrication and to study the process control of nanoimprint lithography.In this thesis, a nanoimprint system is designed and set up. This nanoimprint system is designed to be suitable for both thermal nanoimprint lithography and UV-curing nanoimprint. Furthermore, it performances very well in 3-D micro-structure fabrication with size from 2 millimeters to 50 nanometers. A novel sample wedge compensation module is also presented, which greatly improves the pattern uniformity of the final microstructure. Besides, the wedge compensation module has its secondary function of overload protection.A polymer single-axis mechanical tester is also presented to study the mechanical properties of a photo resist at different temperature, because a good control of nanoimprint process requires fundamental understanding of the underlying mechanical properties of polymers. A new six-axis force sensor is designed and built for the single axis tester and its performance is verified. The force sensor features high level of intrinsic decoupling of the signals from the strain gauges, which greatly simplifies the design of the signal processing system and reduces cost. The measurement principle and simulation results of the sensor are presented and the decoupling algorithm is discussed.Three type of molds fabrication process for nanoimprint lithography are also presented. Using these molds, nano-dot-array with 200nm diameter, binary optical micro-lens array, refractive micro-lens array, cross micro-fluidic channel and cap for glucose test strips are fabricated by thermal nanoimprint process. Futhermore, the control method of imprint temperature, seperation temperature, pressure and other parameters in nanoimprint process is studied.