Patent ID: 7976216

Claim:
A method for estimating the temperature of a wafer, the method comprising: placing a wafer comprising silicon proximate at least one measurement device; performing a measurement that can be used to determine an absorption coefficient, α, of said silicon comprising the wafer at a first wavelength, λ; determining a value for said absorption coefficient, α, of said silicon at said wavelength, λ; and calculating an estimate of the wafer temperature, wherein said estimate takes a value that lies between a lower limit, T−δT and an upper limit T+δT; wherein δT is less than or equal to 30 K, and T =(−1210.8+1863.6λ−506.84λ 2 )α 0.46449−0.38607λ+0.10584λ 2 , when the value of T is in degrees Centigrade, the value of said wavelength, λ, is in units of microns, and the value of said absorption coefficient, α, is in units of cm −1 .