Simulations of embossing process for micro features fabrication

Abstract

With the development of the micro- and nano-fabrication industry, roller to roller embossing has been proven to yield large areas of continuous, robust patterns for devices such as DNA chips, optical switches, micro reactors, ink jet printing heads and accelerometers, which implies that this process has a very high potential in manufacturing industry. Before such mass production could take place, the dimensions produced should meet the requirement, while some researchers demonstrated that the difference between the pile-up of the leading edge and the trailing edge of a micro channel running perpendicular to the rolling direction in a roller to roller embossing system configuration, the leading edge's pile-up is much higher than the trailing edge's at certain temperatures.

In this research, software MATLAB® is applied to do the simulation work. Power-law equation ofpolymer rheology is applied to derivate the shear force ofmicrostructures, and the Lagrangian-Eulerian (ALE) description coupled with three conversation law '(Mass, Energy, Momentum) is utilized to describe the motion and forming of polymer melt flow. Based on these two methods above, simulation results of asymmetric pile-up are achieved. According to the results obtained in simulations, it is found that the shear force induced during roller embossing process is proportional to pressure and rheology index, while parameter of temperature seems to have no effect on it; the height and asymmetry of pile-up increase with the growing temperature and shear force but

decrease beyond one certain temperature; when a synchronized top and bottom rollers driven system is applied to replace the single roller driven system, the effect of pile-up in embossed microstructures is minimized under same conditions.