Research On The Simulation Of Electron Beam Lithography Based On Monte Carlo Method

Electron beam lithography(EBL)is a microfabrication technology that plays an important role in both semiconductor and nanotechnology fields.Compared with ordinary optical lithography,it has high resolution,strong mask-making ability,and high Advantages such as precision processing and easy control.However,the fine preparation of MEMS microstructures has a complicated process.If experimental methods are used for production and processing,it is necessary to repeatedly test to complete the manufacturing of the microstructures,which requires a lot of time and money to be invested in the process.If the computer simulation of the etching process is carried out by establishing a model to realize the prediction of the lithography result,it will effectively shorten the development time and production cycle,and save the material cost.On the one hand,the current simulation software for electron beam lithography machines is relatively expensive.Therefore,it is necessary to independently develop a set of process simulation software and compare with experimental results to improve the accuracy of the software.On the other hand,the current electron beam lithography still has the problem that the proximity effect affects the resolution,so the proximity effect can be studied and optimized through simulation.On the basis of a series of physical theories and models proposed by predecessors,this paper establishes the models of electron scattering in solids at low energy and high energy,including determining the type of scattering cross section,the parameters of the scattering process,and the conversion of the coordinate system,etc..The model can cover more energy range and calculation is faster.Due to the randomness of electron scattering,the Monte Carlo method is used as a probabilistic statistical method.This method is used to simulate the electron scattering process in the photoresist and the substrate,and it is programmed by Matlab software In simulation,the corresponding scatter diagram,horizontal and vertical deposition energy distribution diagrams were made,and the relationship between them and the incident electron beam energy,photoresist thickness,substrate material and other factors were analyzed,and the corresponding conclusions of improved resolution were obtained.And compared with the conclusions in the literature to verify the reliability of the model.Furthermore,using this model,under the platform of Exposure software,a three-dimensional development profile can be simulated,so that the etching topography can be viewed more intuitively,thereby facilitating subsequent parameter optimization.Finally,the application of etching simulation is further studied.Based on the established model,a relatively complex three-dimensional pattern structure is designed and etched,and compared with actual experimental results.The error can be controlled within 6% under a given process.