Microstructure patterning on glass substrate by imprinting process

This paper proposed a thermal imprinting process for transferring microscale patterns from a silicon mold to a glass substrate. Both finite element simulation and experiment were conducted to investigate the formability of microscale glass patterns. Herein, K-PG375 was used as the glass substrate. An FEM model of the periodic microstructures with prescribed boundary conditions was first established. Then, the geometrical parameters, such as aspect ratio, duty ratio, and substrate ratio, process parameters including imprinting temperature, velocity, holding time, etc., as well as the performance index, filling factor, were defined. From the simulated pressure and velocity distributions of glass flow, the mechanism of glass forming was obtained, which provided a guideline for performing the following experimental study. The experiments were conducted by using a homemade thermal imprinting machine. The process parameters were tuned according to the simulation conditions and an SEM was used for observing the geometries of the mold and the transferred patterns. Good agreement between simulation and experimental results were achieved and the 2 μm grating patterns were successfully imprinted on a 12.5 mm square glass substrate.