Temperature sensing methods and apparatus
AssigneeElectrotech Limited
InventorJulian Darryn White
Life of this patent
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Abstract
This invention relates to apparatus for sensing, remotely, the temperature of a semi-conductor wafer and includes means for shining a single frequency light 11 onto the surface 12 of a semi-conductor wafer 13 so that some of that light is scattered. The scattered light is focused by a lens 15 and the single frequency is filtered out of the scattered light by notch filter 17. The filtered beam is split by beam splitter 18 and the resultant two beams are filtered so that they respectively pass only the Stokes and anti-Stokes frequencies respectively. The intensities of these respective light beams are then measured and from these the temperature of the semi-conductor wafer is calculated.
Claims24
Apparatus for sensing the temperature of a remotely positioned workpiece which is spaced from said apparatus comprising:
- a light source for generating and directing a single frequency light beam onto a surface of the remotely positioned workpiece such that the light beam interacts with the atomic or molecular vibrations of a material of the workpiece;
- optical means for forming a beam of light scattered from the surface;
- first filter means for filtering out the single frequency from the scattered light beam;
- beam splitter means for splitting the scattered beam, either before or after the single frequency is filtered by said first filter means, into two separate beams;
- a first optical path for one of the two separate beams comprising second filter means for passing only the Stokes frequency light related to the single frequency and a detector for detecting the intensity of the Stokes frequency light;
- a second optical path for the other of the two separate beams comprising third filter means for passing only the anti-stokes frequency light related to the single frequency and a detector for detecting the intensity of the anti-Stokes frequency light;
- and
- means for calculating the temperature of the workpiece from the detected intensities of the Stokes and anti-Stokes frequency lights.
A method of remotely sensing the temperature of a workpiece comprising:
- illuminating a surface of the workpiece with light of a single frequency such that the light interacts with the atomic or molecular vibrations of a material of the workpiece;
- forming a beam of light scattered from the illuminated surface of the workpiece;
- filtering the single frequency form the formed beam;
- detecting, from the filtered beam, light intensities at the Stokes and anti-Stokes frequencies, respectively, associated with the single frequency, and
- calculating the temperature of the workpiece from the detected light intensities.
Dependencies are inferred from the claim text.