Role of sidewall scattering in feature profile evolution during Cl2 and HBr plasma etching of silicon

Abstract

Articles you may be interested inFeature profile evolution during shallow trench isolation etch in chlorine-based plasmas. II. Coupling reactor and feature scale models Coupling reactor-scale models of plasma etching equipment to device-scale models of feature profile evolution offers the potential for increased levels of virtual design of both capital equipment and process recipes. In this article, a combined reactor-and feature-scale model of crystalline silicon feature profile evolution is described, and simulation results of isolated trench and isolated line etching with Cl 2 and HBr plasmas are compared to experimental data. By incorporating reactor-scale predictions of plasma properties along with assumptions concerning the details of energetic particle scattering from surfaces, we are able to predict both the etch rate and the shape of evolving features. Important in the comparison to experiment is the proper prediction of ''microtrench''-free high aspect ratio trench etching in the case of HBr, contrasted with the occurrence of deep microtrenching when Cl 2 plasmas were used. These results suggest that a thorough knowledge of the details of energetic ion scattering from all evolving surfaces is required before accurate feature profile evolution predictions can be made.

Properties of deep etched trenches in silicon: Role of the angular dependence of the sputtering yield and the etched species redeposition

“…Under similar conditions, the simulation results obtained by Vyvoda et al [12] show the main role of the ion scattering on the trench sidewalls. Under our process conditions, no microtrenching appears and this is well reproduced by the simulator.…”

Plasma-etching profile model for SiO/sub 2/ contact holes

“…The microhole (a microtrench in a contact hole) is well fitted by the model in the plot. The cause for the formation of microtrenches has been reported as either the ions scattered off the sidewall or the mask [41], or the change of ion trajectory due to the differential charging [42]. As these factors are not included in this model we conclude that the formation of the microhole in the plotted etch profiles is due to the different shadowed effects of ions and neutrals.…”

Nanoscale pattern transfer for templates, NEMS, and nano-optics

“…5 Experimental studies and modeling of profile development in sub-micron patterned Si undergoing Cl 2 and HBr dry etching have evolved over the last 10 years. 5,[7][8][9][10][11][12][13][14][15] For the purpose of precisely controlling profiles for imprint templates for nanodevices, we extended the experimental studies to the nanoscale regime. 16,17 Here we discuss how ion interactions with the feature sidewalls and mask can completely dominate the overall feature shape as features shrink.…”