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Optical film thickness measurement method, film formation method, and semiconductor laser fabrication method

  • US 5,724,145 A
  • Filed: 07/12/1996
  • Issued: 03/03/1998
  • Est. Priority Date: 07/17/1995
  • Status: Expired due to Term
First Claim
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1. An optical film thickness measurement method in which a monitor light beam is radiated towards a substrate during the formation of a stack of films on said substrate, and optical film thickness is measured from extreme values of the reflection intensity of light reflected therefrom,wherein said stack of films, comprises:

  • a first film having a reflectance of at least 98% within a predetermined wavelength range; and

    a second film formed on said first film and having an absorption coefficient of 1000 cm-1 or less within said predetermined wavelength range;

    said optical film thickness measurement method comprises the steps of;

    measuring said first film by a first monitor light beam having a predetermined wavelength dependent on the predetermined wavelength range; and

    measuring said second film by a second monitor light beam having a wavelength that differs from said predetermined wavelength range.

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