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Non-contact temperature measurement of a film growing on a substrate

  • US 5,377,126 A
  • Filed: 09/13/1991
  • Issued: 12/27/1994
  • Est. Priority Date: 09/13/1991
  • Status: Expired due to Fees
First Claim
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1. Apparatus for controlling the temperature of a surface of a film-substrate composite while the film is undergoing a change in thickness, comprising:

  • heater apparatus for heating the film-substrate composite;

    detector apparatus for detecting radiance from the surface of the film-substrate composite and generating an electronic radiance signal corresponding to the detected radiance;

    computing apparatus including means for generating an electronic temperature signal which corresponds to the temperature of the surface of the film-substrate composite, said generating means converting the electronic radiance signal to the electronic temperature signal by use of a radiance/temperature relation comprising;

    ##EQU5## where;

    S(t) is the electronic radiance signal at time t,ε



    ,t) is the emissivity function at wavelength λ and

    time t and depends on the film thickness d1, where d1 changes with time,T(t) is the real temperature of the film-substrate composite,Tb is the equivalent blackbody temperature of the film-substrate composite,eb is the blackbody hemispherical emissive power,λ

    1 and λ

    2 are the lower and upper wavelength limits,R(λ

    ) is the spectral responsivity, where R(λ

    )=Rd



    o

    ),Rd

    ) is the electronic radiance signal of the detector apparatus per unit energy, where Rd

    )=dS/dΦ



    o

    ) is the spectral transmittance of all optical elements,Φ

    is the radiance energy arriving at the detector apparatus per unit time,t is time,λ

    is the wavelength of the radiance, andC is a geometric constant based on the detector apparatus and is independent of wavelength; and

    control apparatus responsive to the electronic temperature signal for controlling the output of the heater apparatus to cause the temperature of the surface of the film-substrate composite to approach a predetermined value.

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