Apparatus for and method of heat-treating a wafer

A method of temperature-conditioning a plurality of wafers, said method comprising:

• measuring the temperatures at different locations across the surface of a wafer after the wafer is temperature-conditioned in a reference temperature-conditioning apparatus;
• using the measured temperatures to determine a desired distribution of surface temperatures for the plurality of wafers;
• disposing a plurality of temperature-conditioning apparatuses in parallel, each having a respective heat transfer plate;
• placing each of the plurality of wafers in position above the upper surface of a respective heat transfer plate of the temperature-conditioning apparatuses, which heat transfer plate produces heat used in carrying out a temperature-conditioning process;
• while the wafers are spaced above the upper surface of the heat transfer plates, respectively, carrying out the temperature-conditioning process on the wafers by transferring heat between the heat transfer plates and the wafers;
• and
• before the temperature-conditioning process is carried out on the wafers using the heat transfer plates, respectively, independently determining for each heat transfer plate a spacing of the wafer from the upper surface of the heat transfer plate and an inclination of the wafer relative to the upper surface of the heat transfer plate tending to produce said desired distribution of surface temperatures across the wafer when the wafer is temperature-conditioned using the heat transfer plate, and wherein said placing of the wafers in position comprises setting the wafers above the heat transfer plates with said independently determined spacings and inclinations relative to the upper surface of the transfer plates.