Abstract: A radiometric system (10) typically used in semiconductor wafer processing has reduced optical losses, improved wavelength selectivity, improved signal to noise, and improved signal processing to achieve wafer temperature measurements from about 10° C. to 4,000° C. A YAG rod collection optic (12) directly couples specimen radiation (14) to a filter (18) and photo detector (20). The filter determines which radiation wavelengths are measured, and optionally includes a hot/cold mirror surface (22) for reflecting undesired radiation wavelengths back to the specimen. The detector is formed from doped GaAlAs having a peaked response near 900 nm. A signal processor (28) converts the signal into a temperature reading.

Abstract: A radiometric detector (10) has reduced optical losses, improved wavelength selectivity, improved signal to noise, and improved signal processing methods to achieve temperature measurements of an object (16) from about 10° C. to 4,000° C. A YAG rod collection optic (12) directly couples object radiation (14) to a filter (18) and photo detector (20). The filter determines which radiation wavelength range is measured, and optionally includes a hot/cold mirror surface (22) for reflecting undesired radiation wavelengths back to the specimen. In a preferred measurement method, at least two detectors are employed, each detecting a different wavelength range. A dual-wavelength temperature measurement computation is employed that is independent of radiation transmission losses and the emissivity of the object being measured.

Abstract: The temperature of a semiconductor wafer (160) is measured while undergoing processing in a plasma (168) environment. At least two pyrometers (162, 164) receive radiation from, respectively, the semiconductor wafer and the plasma in a plasma process chamber. The first pyrometer receives radiation from either the front or rear surface of the wafer, and the second pyrometer receives radiation from the plasma. Both pyrometers may be sensitive to the same radiation wavelength. A controller (170) receives signals from the first and second pyrometers and calculates a corrected wafer emission, which is employed in the Planck Equation to calculate the wafer temperature. Alternatively, both pyrometers are positioned beneath the wafer with the first pyrometer sensitive to a first wavelength where the wafer is substantially opaque to plasma radiation, and the second pyrometer is sensitive to a wavelength where the wafer is substantially transparent to plasma radiation.

Abstract: A radiometric system (10) typically used in semiconductor wafer processing has reduced optical losses, improved wavelength selectivity, improved signal to noise, and improved signal processing to achieve wafer temperature measurements from about 10° C. to 4,000° C. A YAG rod collection optic (12) directly couples specimen radiation (14) to a filter (18) and photo detector (20). The filter determines which radiation wavelengths are measured, and optionally includes a hot/cold mirror surface (22) for reflecting undesired radiation wavelengths back to the specimen. The detector is formed from doped GaAlAs having a peaked response near 900 nm. A signal processor (28) converts the signal into a temperature reading.