Method and apparatus for measuring temperature

An apparatus and method for measuring a temperature of a substrate are provided. In one or more embodiments, an apparatus for estimating temperature is provided and includes: a plurality of electromagnetic radiation sources positioned to emit electromagnetic radiation toward a reflective plane; and a plurality of electromagnetic radiation detectors. Each electromagnetic radiation detector is positioned to sample electromagnetic radiation emitted by a corresponding electromagnetic radiation source of the plurality of electromagnetic radiation sources. The apparatus also includes a pyrometer positioned to receive electromagnetic radiation emitted by the plurality of sources of electromagnetic radiation and reflected from a substrate disposed at the reflective plane and electromagnetic radiation emitted by the substrate. The apparatus includes a processor configured to estimate a substrate temperature based on electromagnetic radiation emitted by the substrate. Methods of estimating temperature are also provided