×

Lens heating compensation systems and methods

  • US 8,570,485 B2
  • Filed: 05/29/2009
  • Issued: 10/29/2013
  • Est. Priority Date: 06/03/2008
  • Status: Active Grant
First Claim
Patent Images

1. A method of calibrating a photolithographic system, comprising:

  • generating a cold lens contour for a reticle design;

    generating at least one hot lens contour for the reticle design;

    characterizing aberrations induced by a corrective system in a correction model; and

    optimizing a process window of the photolithographic system using the correction model, wherein optimizing the process window includes controlling the corrective system such that variations in parameters of one or more features of the reticle design obtained from the cold lens contour and the at least one hot lens contour lie within a predetermined limit over an optimal amount of photolithographic system process settings,wherein generating the cold lens contour includes using a lens model based on measurements obtained while a lens of the photolithographic system is maintained within a nominal operating temperature range,wherein each hot lens contour is generated using a corresponding lens heating model, wherein the lens heating model characterizes light-induced heating of the lens in a photolithographic process, andwherein optimizing the process window includes minimizing variations in critical dimensions caused by lens heating by inducing other variations in critical dimensions caused by lens aberrations.

View all claims
  • 2 Assignments
Timeline View
Assignment View
    ×
    ×