Paper PS1-ThA10
Feature Profile Simulator FPS-3D

Thursday, October 21, 2010, 5:00 pm, Room Aztec

Reliable and predictive feature profile evolution simulation is an extremely important topic for nanotechnology and semiconductor industry. If successfully solved, it will allow significant saving of time and resources presently spent on numerous design experiments directed on finding proper chemistries and conditions in a multi-parameter space of search for advanced etching or deposition. FPS-3D is a Monte Carlo code, where launched particles corresponding to the specified fluxes, each particle typically consisting of many gas molecules, or ions, or electrons, interacts with solid materials of the target. A cellular model is used for presenting solid materials. Each cell is a complex object consisting of the body of the cell and its surface layer, and is typically includes many molecules. All material properties and all reaction mechanisms are specified in the chemistry file. The output of gas and ion reactions is characterized in terms of probabilities and yields. The incoming fluxes could be specified via two different options. One option is to use the flux file, where all the data for fluxes of each gaseous species is provided for each energy-angular bin. This file is typically generated by a plasma simulation code (for example, such as HPEM [1], which we are currently using). A second option is to generate fluxes of species according to a few parameters specified in the input file. The second option is especially convenient for considering interactions of particle beams with solid materials. Upon collision of a flux particle with the target, the code determines a particular cell where the reaction occurs. The result of such an interaction could be a removal of some of molecules from the cell, or deposition of similar or different molecules to the cell, or both. The code considers low-energy gaseous species very differently from the high-energy species. The low-energy species are interacting only with the surface layer of the cell by mainly depositing or altering molecules in the surface layer, although spontaneous etching from the surface layer is taken into account as well. The energetic species, on the other hand, could do much more. They could also lead to removal of molecules from the surface layer and from the body of the cell with the yield corresponding to their energy and angle of incidence. Such yields could be larger than one for higher energies. This report will present technical details of FPS-3D and give a few examples of its operation in 2D and 3D. The author is thankful to Drs. S.-Y. Kang of TEL TDC and P. Miller of HFS for valuable discussions.

[1] M.J. Grapperhaus, M.J. Kushner, J. Appl. Phys. 81, 669 (1997).