| Summary: | 碩士 === 國立成功大學 === 機械工程學系 === 106 === The deep trench isolation (DTI) structure plays an important role in the three-dimensional integrated circuit, and the most efficient way to etch an anisotropic DTI structure is to use the BOSCH etching method. However, setting the operating parameters of the BOSCH is a complicated issue. If the influence of the operating parameters on the etching profile can be known in advance, the process efficiency can be improved. In this study, a theoretical energy flux model and an experimental energy flux model are used to study the correlations between operating parameters and etching profiles. The ANSYS/LS-DYNA numerical analysis software were used to simulate the etching profile, and Johnson-Cook failure criterion was added as the silicon failure condition. Through the theoretical energy flux model, the energy flux of SF6 and C4F8 etching gases at different coil powers can be calculated separately. Through the experimental energy flux model, the relationship between the etch rate and the energy flux of the SF6/C4F8 mixed gas, and the relationship between the gas flow rate and the energy flux can be established. Combining the results of theoretical and experimental energy flux models, the energy flux ratio contributed by each gas in the mixed gas can be obtained. The etching profile obtaining from different energy fluxes can be simulated from ANSYS/LS-DYNA. This study proposes a new way to simulate the etching profile. Using the Gaussian distribution function to adjust the morphology of the plasma indenter and iteratively to find the maximum pressure need to be assumed for the plasma indenter. Comparing the simulated etching profiles with the experimental samples etching profiles obtains the maximum relative error to be controlled within 6.52%.
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