Etching characteristics and profile simulation of silicon.

Abstract

The anisotropic wet etching characteristics of crystal silicon are complex and easily affected by etching conditions and mask shapes, which makes it difficult to accurately predict and control the evolution process and 3D etched profile. This study is based on experimental data on the etching rate and mask etching structure of crystal silicon, and analyzes in detail the anisotropic etching mechanism and mask etching forming process, and then establishes an etching process simulation model using the Level Set method. The model first obtains the etching rate of all crystal planes by interpolation of the etching rate of a few sample crystal planes, then establishes the control equation of the etching motion interface based on the level set function and uses the finite difference method to solve the equation to track the evolution of the etching interface, and finally achieves the high-precision simulation of the 3D etched profile under various masks (window mask, mesa mask and double-sided mask). Experimental results show that the simulation results of the model are in good agreement with the actual situation, and the model has good adaptability and predictive ability for different etching systems and mask wafers with different shapes. In addition, the modeling theory is also applicable to the etching profile simulation of quartz and other crystalline materials, and has high simulation accuracy.