Semiconductor wafer temperature determination by optical measurement of wafer expansion in processing apparatus chamber

DETAILED DESCRIPTION It is a primary objective of the present invention to provide a method and apparatus for instantaneously and accurately determining the temperature of thin plate-like articles such as semiconductor wafers during processing in, for example, the vacuum chambers of semiconductor wafer processing machines.
It is a more particular objective of the present invention to provide a temperature determination system, which can be used for temperature measurement or temperature control in thermal processing modules of semiconductor wafer processing machines such as in degassing chambers thereof where stacked pluralities of wafers are simultaneously processed.
It is a further and more particular objective of the present invention to provide a noncontact instantaneous temperature determination method and apparatus employing components located outside of a processing chamber that will instantly and accurately determine the temperature of the objects within.
It is an additional objective of the present invention to provide a thermal expansion optical measurement system having low sensitivity to wafer positioning error or dimensional tolerances, and which will otherwise overcome the problems of the prior art.
According to the principles of the present invention, there is provided a method and apparatus for determining the temperature of thin plate-like articles, such as semiconductor wafers formed of materials of known coefficient of thermal expansion, during processing in sealed chambers, such as vacuum processing chambers of semiconductor wafer processing machines.
In accordance with the principles of the present invention, changes in the dimension of a wafer are measured as the wafer is heated or cooled from a first known temperature to a second unknown temperature.
The need for such a measurement is typical for example, where wafers are placed in a pretreatment module at atmospheric temperature conditions, and then heated to a second temperature at which the wafers will be thermally processed or subjected to some other process in which temperature must be monitored or controlled