| 摘要 |
PURPOSE: To accomplish real time temperature measurement by measuring optical parameters affected by a light scattering phenomenon induced by temperature dependent surface roughness to determine the temperature of a workpiece. CONSTITUTION: On the receipt of a modulation signal 110, a laser driver 108 sends modulated drive current to a laser source 102, which sends the first and the second laser beams to a multiplexer 114. Two laser beams are combined 114 into a beam 124, and a collimated lens 122 focuses the beam 124 on a surface 22 on the back side of a wafer 10 so as to receive reflected beam 124, and a change in a reflectance R based on a change of wavelength is measured. The beam 124 is separated 128 to a reflection fixed beam, and signals detecting 132, 133 the beam power are conditioned 134, 136, and then, a change data for the reflectance R is extracted by means of a signal processor 138. If a temperature of the wafer 10 is previously known, a double mean surface roughness r0 of the surface 22 is calculated 164, and an unknown temperature T can be computed in real time from the roughness r0 value. |
