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Real-time in-line testing of semiconductor wafers

  • US 5,661,408 A
  • Filed: 03/01/1995
  • Issued: 08/26/1997
  • Est. Priority Date: 03/01/1995
  • Status: Expired due to Term
First Claim
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1. An apparatus for the real-time, in-line testing of a semiconductor wafer, having a first surface and a second surface, during semiconductor processing, said apparatus comprising:

  • a head assembly comprising;

    a modulated light source exposing at least a portion of said semiconductor wafer to light of a predetermined wavelength and modulated at a predetermined frequency; and

    a voltage sensor comprising a plurality of electrodes positioned adjacent said first surface to detect a surface photovoltage induced at said first surface of said semiconductor wafer in response to said light from said modulated light source without contacting said wafer, said plurality of electrodes sufficient for detecting said surface photovoltage on said first surface; and

    a conveying apparatus conveying said wafer adjacent said voltage sensor of said head assembly during said semiconductor processing.

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