×

Lithographic apparatus, level sensor, method of inspection, device manufacturing method, and device manufactured thereby

  • US 7,248,337 B2
  • Filed: 01/14/2004
  • Issued: 07/24/2007
  • Est. Priority Date: 01/14/2003
  • Status: Active Grant
First Claim
Patent Images

1. A lithographic apparatus comprising a level sensor configured to measure a height of a wafer surface, said level sensor comprising:

  • a first reflector having at least two layers and being configured to direct a beam from a light source toward the wafer surface; and

    a second reflector having at least two layers and being configured to direct the beam from the wafer surface to a detector,wherein a magnitude of an apparent depression of the wafer surface due to translation of the beam at reflective surfaces of the first and second reflectors is less than thirty-five nanometers.

View all claims
  • 1 Assignment
Timeline View
Assignment View
    ×
    ×