Patent ID: 7578616

Claim:
In a plasma processing system, an apparatus for measuring a temperature of a substrate, the apparatus comprising: a unit configured to be in thermal contact to said substrate, said unit including at least a phosphor material and a second phosphor material that directly contacts the phosphor material, said phosphor material being configured for measuring a first temperature range, said phosphor material producing a fluorescent response in a first wavelength range when exposed to a electromagnetic radiation in a second wavelength range, said fluorescent response decaying at a decay rate that is related to a temperature of said phosphor material, said second phosphor material being configured for measuring a second temperature range; and a barrier window positioned between said phosphor material and a plasma, wherein said barrier window allows at least a portion of said first wavelength and said second wavelength to be transmitted, wherein when said electromagnetic radiation is transmitted to said phosphor material through said barrier window, said temperature is determined from said decay rate of said fluorescent response, and wherein said phosphor material, said second phosphor material, and said barrier window are positioned in a notch in said substrate.