LPCVD profile simulation using a re-emission model

A novel, physically based 3D simulator has been developed that includes the dominant effect of re-emission. This simulator is part of the Stanford Profile Emulator for Etching and Deposition in IC Engineering (SPEEDIE). Unlike previous simulators which consider only the arrival of deposition precursors by unshadowed direct transport and by surface diffusion, SPEEDIE also considers transport into shadowed areas by adsorption and re-emission. The importance of re-emission was established by using overhang test structures to separate the roles of surface diffusion and re-emission. For the depositions investigated (SiO/sub 2/, poly-Si and W) it was found that re-emission dominates over surface diffusion in controlling surface contours. Using the simulator to fit experimental LPCVD (low-pressure chemical vapor deposition) SiO/sub 2/ profiles, it was found that a single constant sticking coefficient model with a cosine re-emission distribution gave excellent fits independent of geometry for a given deposition condition.<
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