Real-time control of a wafer temperature for uniform plasma process

Our developed non-contact method for measurement of temperature of silicon (Si) wafer by using autocorrelation-type fourier domain low coherence interferometer has advantageous in accuracy and rapid response. We demonstrate measurements in temperature for Si wafer at real-time during plasma process and in estimation of heat flux to the wafer from plasma, involving heats balanced plasma source and conductive loss in Si. The analysis indicated that other heat sources like the chamber parts with relatively high temperature impact on the duty ratio during the process with feedback control of the wafer teperture.