Research of the in-situ temperature measurement system for silicon wafers.

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The following 3 research items were carried out during the term of the project. Each research result is briefly described.(1) Hybrid-type surface temperature sensor.The hybrid-type surface temperature sensor combines the advantages of contact and non-contact methods and offers a way of overcoming the weak points of both methods. This sensor is actually a modified radiation thermometer that can conduct an emissivity free measurement. Under thermally steady state conditions, it can be concluded that the systematic error is-0.5 K, and the random error is within 10.5 K in the 900 to 1000 K temperature range. However, it takes several tens of seconds to reach thermally steady state conditions. This is far from an in situ measurement application. Instead, the transient heat transfer response was utilized by a newly developed rapid response hybrid-type surface temperature sensor that has a 1 s response time. A temperature measurement with this sensor is possible within ±1 K over the same temperature range. This sensor has the potential for use in calibrations of in situ temperature measurements, especially in the semiconductor industry.(2) Radiation thermometry by use of polarized radiances at high temperature.The emissivity of a silicon wafer has experimentally been investigated at a moderately high temperature (above 900 K) from the viewpoint of spectral, directional, and polarization characteristics of thermal radiation. The direct relationship between the ratio of p-and s-polarized radiance and polarized emissivity, as estimated by a simulation model, was confirmed experimentally. The method has also the potential for an in situ application for the semiconductor industry.(3) Emissivity-invariant condition.This finding was experimentally confirmed to be valid for some silicon wafers. This finding is very important for process in situ temperature measurement. Further intensive study is necessary to fully confirm the validity of this condition.