| dc.description.abstract | Chemical vapor deposition is a common method in semiconductor thin film growth processes. The flatness is improved for 12-inch epitaxial wafers required for semiconductor processes below 10 nm. The key technologies are: 1. Ultra-uniform epitaxial film 2. The wafer substrate is matched with the shape of the epitaxial film. In this study, the multi-physics finite element analysis software (COMSOL Multiphysics) was used to establish the epitaxial process system. The thermal field, flow field and species transfer simulation were performed using the applied material Centura® atmospheric pressure epitaxy reaction chamber. The effects of different Accuset, Upper liner and low liner, and Upper dome on the growth rate of the film were compared.
When growing large-size tantalum epitaxial films, the size of the reaction chamber is too large and the geometry is too complicated, so it is not easy to achieve good uniformity of the film above the wafer. Therefore, this study first establishes a three-dimensional physical model, when hydrogen and trichlorosilane is introduced into the reaction chamber, trichlorosilane and hydrogen will react with temperature to produce a chemical surface adsorption reaction. When the process temperature is 1050℃ to 1150 °C, the different inlet flow ratio and the geometry of the gas mixing zone will affect the shape, film deposition rate and flatness of the bismuth epitaxial film. From the simulation results, it is found that the temperature field analysis removes the geometry of the gas mixing zone, helps the gas to enter the cavity, reduces the temperature gradient, makes the concentration of the mixed gas more uniform, and achieves a better uniformity of the film. From the quartz cover design, the height of the cavity and the radius of curvature also affect the Growth rate profile. The smaller the radius of curvature, the larger the cavity height, and the ratio of the intake flow rate, the better uniformity results.
Then, in the process parameters, the addition of the rotation condition can also achieve the effect of improving the uniformity. In the simulation results, the uniformity after the addition of the rotation speed is better than that when the rotation is not performed, and the increase of the rotation speed can also improve the uniformity. After the partition is removed, in addition to the advantage that the rotation can improve the uniformity, the phenomenon that the local growth rate is low can be effectively improved.
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