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Non-contact method for determining the presence of a contaminant in a semiconductor device

  • US 6,255,128 B1
  • Filed: 08/06/1998
  • Issued: 07/03/2001
  • Est. Priority Date: 08/06/1998
  • Status: Expired due to Fees
First Claim
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1. A non-contact method for determining whether a contaminant is present in a semiconductor wafer having a substrate/dielectric interface formed thereon, comprising:

  • field inducing a first junction in equilibrium inversion in said semiconductor wafer device;

    forming a contaminant junction near said substrate/dielectric interface when said contaminant is present in said semiconductor wafer by adding charge and poising said first junction out of equilibrium;

    measuring a change in a surface voltage as a function of time to obtain a surface voltage measurement, said change being negligible when said contaminant is present in said semiconductor wafer; and

    determining whether said contaminant is present in said semiconductor wafer from said change in said surface voltage.

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