Abstract

In an apparatus and process for heating, e.g., a semiconductor wafer within a processing chamber, the wafer is exposed to a flux of electromagnetic radiation from lamps energized by alternating electric current. The surface temperature of the wafer is measured, and responsively, the radiation flux is controlled. The temperature measurement procedure includes collecting radiation propagating away from the wafer in a first probe, collecting radiation propagating away from the wafer and radiation from the lamps in a second probe, and detecting radiation collected in the respective probes. This procedure further involves deconvolving the multiphase ac component of the signal received from each probe, determining the linear functional relationship of the first probe signal as a function of the second probe signal resulting from time-variations of the energizing current, and using this linear functional relationship along with the signal data according to a mathematical expression to infer the temperature. The probes are oriented such that the first probe samples radiation from a portion of the wafer that subtends an angle Ω1 from the first probe and the second probe samples radiation from the same portion of the wafer and at least one lamp which subtends a solid angle Ω2.

Other References

• Fiory et al, "Optical Fiber Pyrometry With In-situ Detection fo Wafer Radiance and Emittance--Accufiber's Ripple Method", Mat. Res. Soc. Symp. Proc., vol. 30