| 摘要 |
PURPOSE:To make it possible to execute accurate test by disconnecting the heater and thermister in a thermal plate from a temperature controlling part at the time of testing a wafer. CONSTITUTION:A coil K1' is energized by a driving unit 24 at the timing 1 and a relay K1 turns NO side, to disconnect a thermister 211 from a temperature controller 22, a resistor Rs is connected and the power supply for a heater 212 is also turned OFF. At the time t1, the temperature controller 22 follows up, the relay K1 terminates the operation and at the timing 2 the relay K2 turns NO side with the control signal and the controller 22 is disconnected. The time t2 between the timings 2 and 3 is the accurate measurement time. At the timing 3, measurement completes, the heater 212 is connected to the NC side of relay K2, while at the time t3 the relay K2 make contact, at the timing 4, the relay K1 turns to NC, the thermister 211 is connected again to the temperature controller 22 and thereby a temperature of heater 212 is detected. The temperature controller 22 sends a signal to the driving units 24, 25 and maintains the heater 212 at the specified temperature. |
