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1999
Conference Paper
Titel
Simulation of a Coating Protection for an In Situ Ellipsometer in a CVD Furnace
Alternative
Simulation des Schutzes vor Beschichtung fĂ¼r ein In Situ Ellipsometer in einem CVD Ofen
Abstract
We investigated an ellipsometer integrated in a chemical vapor deposition furnace as an in situ layer thickness sensor. The laser beam of the ellipsometer is guided by prism-based optics into the furnace tube and onto the surface of one of the wafers. To reduce coating on the prisms, inert gas purging is employed. Simulations were carried out to study the influence of prism purging on the layer thickness homogeneity on the wafers. Further simulations were performed to optimize the purging gas inlet with the purpose of minimizing the coating on the prisms. The simulations are based on solving the Navier-Stokes equations and the species concentration equations with the software package Phoneics-CVD.