Laser luminescence monitor for material thickness
March 2, 2007. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesReactive ion etching of III-V semiconductor compounds Method and apparatus for monitoring etching Method for end point detection in a plasma etching process Plasma-assisted etch process with endpoint detection Spectroscopic monitoring of gas-solid processes End-point detection in plasma etching or phosphosilicate glass Method of monitoring status of a silicon layer by detecting, emission spectra variable during etching Optical emission end point detector Optical emission spectroscopy end point detection in plasma etching Patent #: 4493745 InventorApplicationNo. 07/020402 filed on 03/02/1987US Classes:438/16, Optical characteristic sensed118/712, WITH INDICATING, TESTING, INSPECTING, OR MEASURING MEANS156/345.25, For endpoint detection204/192.13, Measuring or testing (e.g., of operating parameters, property of article, etc.)204/192.33, Measuring or testing (e.g., of operating parameters, end point determination, etc.)204/298.03, Measuring, analyzing or testing204/298.32, Measuring, analyzing or testing356/632, Of light permeable material427/10Electrical or opticalExaminersPrimary: Powell, William A.Attorney, Agent or FirmInternational ClassG01B 11/06 (20060101)AbstractAn apparatus and method for monitoring a change of thickness of a first material with a first bandgap energy, for disposal over a second material on a wafer and having a second different bandgap energy, wherein at least one of the materials has a direct bandgap. The apparatus comprises means for changing the thickness of the first material layer; means for directing a beam of energy to impinge at an angle on to the surface and to penetrate the wafer, with the beam having an energy sufficient to pump the at least one direct bandgap material to a higher energy state; and means for detecting the induced luminescence from the at least one direct bandgap material to determine when to alter the thickness changing process.The present invention may be used to monitor both deposition and etching processes. It is particularly suited for determining the etch endpoint for III-V semiconductor materials such as GaAs and AlGaAs.Other References
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