Three-Dimensional Miacromachining Simulations Based On The Narrow Band Level Set And Monte Carlo Method

Since micromachining such as RIE,PECVD and DRIE are widely employed for fabricating various devices and functional microstructures,which is corresponding to the performances of MEMS devices.On account of the complicated behaviors of particles such as sticking,scattering,diffusion,recombination and re-deposition in plasma etching and deposition,a synthetic and topographical model is adopted to sketch the complex mechanism.For example,sticking probability,incident angles,energies of particles,reflective probabilities of particles and flux arrivals on the surface are the concrete parameters of the ballistic transport in ray tracing.The velocity deduced by local flux,level set function and material matrix are modeling in narrow band level set method.Compared with other simulators,this simulator contains several more parameters,which is more accurate at the expense of runtime.This paper presents a coupling level set and Monte Carlo model for the plasma-related micromachining in three dimensions.The DRIE process is introduced to enable high aspect ratio by plasma etching and passivation alternation in multiple cycles.This simulator is developed to predict the particle movements from the edge of plasma sheath to the substrate surface and the movements of surface in etching/deposition process.The Ray tracing technique is applied to simulate particle transport and surface kinetics.The velocities of all active grids are obtained by collecting millions of rays.In addition,the narrow band level set method is implemented for the surface evolution.The surface profiles are investigated for various etching/ passivation cycles.The errors can be controlled into 15% given the conditions of microfabrication.This simulator can be served as an accurate prediction tool for some MEMS fabrications.