During CVD process of semiconductor wafer fabrication, maintaining the uniformity of temperature distribution at wafer top surface is one of the key factors affecting the quality of final products. Effect of contact conductance between wafer and hot plate on predicted temperature of wafer was investigated. The validity of opaque wafer assumption was also examined by comparing the predicted results with Discrete Ordinate solutions accounting for semitransparent radiative characteristics of silicon. As the contact conductance increases predicted wafer temperature increases and the differences between maximum and minimum temperatures within wafer and between wafer and hot plate top surface temperatures decrease. The opaque assumption always overpredicted the wafer temperature compared to semitransparent calculation. The influences of surrounding reactor inner wall temperature and hot plate configuration are then discussed.