Multiscale Analysis of Silicon Low-Pressure Chemical Vapor Deposition

We consistently performed computer fluid dynamics (CFD) analysis in a reactor (macroscale analysis) and deposition profile analysis on a submicron hole (microscale analysis) for Si low-pressure chemical vapor deposition (LPCVD). For the gaseous phase and the surface reaction of the SiH 4 source gas, we adopted the dominant reaction model, which involved two intermediates, SiH 2 and Si 2 H 6 , and was based on the Kleijn Model. We analyzed the fluid flow, heat transfer and chemical reactions throughout the entire batch-type reactor, and estimated the Si growth rate, gaseous species concentration, and relative contributions of SiH 4 , SiH 2 and Si 2 H 6 to Si growth. Moreover, the Si-filling profile on a submicron hole was predicted by topography simulation in which the parameters were the growth rate, the relative contribution and the sticking coefficient of each species. The relationship between the relative contribution of SiH 2 , which has a high sticking coefficient, to Si growth and the hole-filling capability was quantitatively clarified from the results of a combination of the two analyses. The hole-filling capability at the wafer edge was deteriorated by the influence of SiH 2 gas produced in the decomposition of Si 2 H 6 gas, which was diffused from outside the wafer. This effect became considerable with increasing temperature. Reducing the wafer pitch will be effective in improving the hole-filling capability because both the SiH 2 generation reaction in the region between wafers and SiH 2 gas diffusion from outside the wafer will be inhibited.