To maintain the quality of a wafer by preventing the rapid cooling of the wafer at the time of cooling it down after heating it, and to control the cooling time duration.

The wafer 1 is polarized while being heated, and then is cooled. At that time, with a heater 23 turned on, a cooling block 30 which is not supplied with a cooling medium is raised to be brought into contact with the heater 23. After tens of seconds, the heater 23 is turned on and the cooling medium is supplied to the cooling block 3 from a cooling medium supply source 5 via a supply pipe 310 and a valve 32 to cool the wafer 1 via the heater 23, a spacer 22, and a pair of heat transmission boards 20 and 21. A cooling medium supply quantity controller 42 calculates a temperature gradient from the temperature measured by a thermo-couple 24. When the measured temperature exceeds a set value, the valve 32 of the supply pipe 310 is closed; and when the measured temperature is the same as or lower than the set value, the valve 32 is opened. Finally, when the temperature falls to a predetermined temperature, the air or nitrogen is supplied for natural cooling.

COPYRIGHT: (C)2006,JPO&NCIPI