Lucent Technologies Inc.

Robert J Chichester

Gordon Albert Thomas

Glenn B Alers

Don X Sun

Harald F Hess

A method is disclosed for processing a silicon workpiece including a hybrid thermometer system for measuring and controlling the processing temperature where fabrication materials have been or are being applied to the workpiece. The hybrid thermometer system uses optical reflectance and another thermometer technique, such as a thermocouple and/or a pyrometer. Real-time spectral data are compared to values in a spectrum library to determine the &ldquo;surface conditions&rdquo;. A decision is then made based on the surface conditions as to how the temperature is measured, e.g., with optical reflectance, a pyrometer, or a thermocouple, and the temperature is measured using the appropriately selected technique. Utilizing the hybrid thermometer system, the temperature of a silicon workpiece may be accurately measured at low temperatures while accounting for the presence of fabrication materials.

Method for processing silicon workpieces using hybrid optical thermometer system

A plurality of PR measurements are simultaneously made at N different spots on a wafer by forming N modulated pump beams and N tunable probe beams, and directing one pump beam and one probe beam so as to form overlapping images at each of the N spots. Each of a like plurality of N photodetectors receives a portion of the corresponding probe beam which is reflected from the surface of the wafer to provide information about the wafer characteristics at each spot. In one embodiment, automatic alignment of the probe and pump beams along a row of N spots is achieved by means of a semi-cylindrical scan head which has an axial cavity overlapping the row of N spots and a plurality of radial cavities organized into separate, but interleaved input and output groups. The cavities of two separate input groups receive optical fibers carrying the probe and pump beams to the row of N spots. The cavities of two separate output groups receive photodetectors for detecting the reflected beam and for monitoring the pump beam. The scan head and/or the wafer are moved relative to one another in order to make measurements at various row locations on the wafer (e.g., to map the wafer).

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Somerville, NJ, United States of America

Robert J Chichester