PURPOSE: To heat a wafer to a uniform temperature and to enhance a yield by a method wherein a quartz sheet having a plurality of holes used to blow an inert gas is installed around a uniform-heating sheet.

CONSTITUTION: A reaction gas discharged from a reaction-gas control part 1 is passed through a gas blowoff sheet 2 and comes into contact with a water 4 supported by means of a wafer support jig 3. Heat from a heater 5 heats a uniform-heating sheet 6; in addition, a quartz sheet 8 having many holes 10 used to blow an inert gas such as N2 or the like introduced from an inert gas control part 7 is installed around the uniform-heating sheet 6. The reaction gas which has reached the neighborhood of the uniform-heating sheet 6 in this manner does not come into contact with the uniform-heating sheet 6 and the quartz sheet 8 thanks to the inert gas blown off from the quartz sheet 6. Accordingly, a reaction product does not adhere to the uniform-heating sheet 6, and a coating material is not stripped off. Since the quartz sheet 8 itself conducts heat well, no proble is caused even when the sheet is installed between the wafer 4 and the uniform-heating sheet 6.