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Surface inspection apparatus and method

  • US 6,654,111 B2
  • Filed: 02/22/2001
  • Issued: 11/25/2003
  • Est. Priority Date: 02/24/2000
  • Status: Expired due to Fees
First Claim
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1. A surface inspection apparatus comprising:

  • a light source section for emitting a first luminous flux and a second luminous flux irradiated on a surface of an inspected object;

    a first irradiation optical system in which the first luminous flux is irradiated on the surface of the inspected object at a first irradiation angle;

    a second irradiation optical system in which the second luminous flux is radiated on the surface of the inspected object at a second irradiation angle different from the first irradiation angle;

    a displacement section for displacing the inspected object relative to irradiation luminous fluxes of the first and second irradiation optical systems;

    a light receiving optical system for receiving scattered light of the first luminous flux irradiated by the first irradiation optical system and produced from an inspection object on the surface of the inspected object and scattered light of the second luminous flux irradiated by the second irradiation optical system and produced from the inspection object on the surface of the inspected object;

    a first light receiving section for converting scattered light of the first luminous flux received by the light receiving optical system into a first light receiving signal;

    a second light receiving section for converting scattered light of the second luminous flux received by the light receiving optical system into a second light receiving signal; and

    a signal forming section for forming a measuring signal on the basis of the first light receiving signal and the second light receiving signal, wherein the first light receiving section and the second light receiving section respectively form the first light receiving signal and the second light receiving signal which are different in sensitivity or dynamic range from each other, wherein the signal forming section synthesizes the first light receiving signal and the second light receiving signal which are different in sensitivity or dynamic range from each other to form the measuring signal, and wherein the signal forming section forms foreign matter data on the basis of the first light receiving signal at a high sensitivity side when both the first and second light receiving signals are not saturated, and forms foreign matter data on the basis of the first light receiving signal at a low sensitivity side when only one of the first and second light receiving signals is saturated.

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