Method of and apparatus for controlling temperature in the processing of a substrate

Apparatus for processing the front surface of a substrate said processing apparatus comprising:

• a processing chamber;
• a substrate holder assembly in said chamber, said assembly having a hole therethrough and through which hole the back surface of a substrate held by said assembly in said chamber will be exposed when the substrate is being processed;
• contactless substrate temperature sensor means for directly sensing the heat emitted from the back surface of a substrate held by said assembly, said sensor means disposed in said chamber in axial alignment with said hole in said substrate holder assembly, and the space between said sensor means and said hole being free of obstacles such that said sensor means will directly face the back surface of a substrate when the substrate is being processed;
• a substrate transfer device;
• a heat emissivity measuring device disposed along a substrate transfer path through which a substrate is transferred by said device to a processing position in said chamber, said heat emissivity measuring device including a heater having an emissivity value of unity, and temperature sensor means for sensing the temperature of heat emitted by a substrate that is heated by said heater;
• and
• emissivity correction circuit means for receiving the outputs of each of said temperature sensor means and for correcting an output of said contactless substrate temperature sensor means based on the output of the temperature sensor means of said heat emissivity measuring device.