| 摘要 |
PURPOSE:To contrive improvement in reliability of various kinds of heat treatments by a method wherein the temperature in a heating furnace at the time when heating is started is detected and the power applied to infrared lamps is controlled in accordance with the detected signal of the above-mentioned temperature detection. CONSTITUTION:An arithmetic operational circuit 13 performs an arithmetic operation on the common electric energy to be supplied to power ratio setting devices 14 and 15 in proportion to the difference between the temperature Tx of a heating furnace when the annealing process for a semiconductor wafer is started and the preset reference temperature T0. The initial furnace temperature Tx when a heat treatment is going to be performed is given by a thermoelectric couple 20. For example, the temperature Tx is the reference temperature T0, and an annealing process is performed by outputting the input power W of the circuit 13 for a fixed time. When the initial temperature Tx, at which the second annealing process is performed under the above-mentioned condition, is higher than T0, the power W is reduced at the rate in proportion to the difference of T0 and Tx, and in the case reverse to the above, the power W is increased and outputted for a fixed time, and the wafer is heated up to the prescribed temperature. As a result, an excellent annealing process can be performed under the same condition at all times. |
