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Controlling thermal expansion of mask substrates by scatterometry

  • US 6,654,660 B1
  • Filed: 11/04/2002
  • Issued: 11/25/2003
  • Est. Priority Date: 11/04/2002
  • Status: Active Grant
First Claim
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1. A system for controlling thermal expansion on a mask during photolithography of an underlying wafer comprising:

  • a photolithography system comprising an irradiation source and a mask, whereby heat accumulates on at least a portion of the mask while irradiating one or more layers of the underlying wafer;

    a mask inspection system for monitoring one or more gratings on the mask to detect expansion therein, the mask inspection system producing data relating to the mask;

    a temperature control system operatively coupled to the mask inspection system and the photolithography system for making adjustments to the photolithography system in order to control the detected expansion on the mask and to mitigate undesirable pitch changes on the mask; and

    a mask cooling system operatively connected to the temperature control system such that the temperature control system signals the cooling system to treat the mask in order to compensate for the detected expansion on the mask.

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