Patent ID: 8417394

Claim:
A substrate processing apparatus comprising: a reaction vessel configured to accommodate at least a product wafer and a filler wafer; a heating unit configured to heat an inside of the reaction vessel; a temperature detector configured to detect a temperature at an inside of the heating unit; and a control device configured to perform a calculation by using a deviation between a set temperature and the temperature detected by the temperature detector and at least one calculation parameter so as to control the heating unit by using a result of the calculation, wherein the control device comprises a calculation parameter setting unit configured to determine the calculation parameter, wherein the calculation parameter setting unit comprises: a first calculation parameter setting unit configured to determine a first calculation parameter correction value based on an accumulated film thickness on the reaction vessel; a second calculation parameter setting unit configured to determine a second calculation parameter correction value based on an accumulated film thickness on the filler wafer; a third calculation parameter setting unit configured to determines a third calculation parameter correction value based on the number of the filler wafers; and a calculation parameter computing unit configured to compute the calculation parameter by using at least the first calculation parameter correction value, the second calculation parameter correction value, and the third calculation parameter correction value wherein the calculation parameter computing unit is configured to compute the calculation parameter at least by multiplying the second calculation parameter correction value by the third calculation parameter correction value.