Method for error reduction in lithography

Abstract

The present invention relates to a method and a system for predicting and/or measuring and correcting geometrical errors in lithography using masks, such as large-area photomasks or reticles, and exposure stations, such as wafer steppers or projection aligners, printing the pattern of said masks on a workpiece, such as a display panel or a semiconductor wafer. A method to compensate for process variations when printing a pattern on a workpiece, including determining a two-dimensional CD profile in said pattern printed on said workpiece, generating a two-dimensional compensation file to equalize fluctuations in said two-dimensional CD-profile, and patterning a workpiece with said two-dimensional compensation file.

1 .- 7 . (canceled) 
   
   
       8 . A method to compensate for process variations when printing a pattern on a workpiece, said method comprising:
 determining a two-dimensional CD profile in said pattern printed on said workpiece,   generating a two-dimensional dose compensation profile to equalize fluctuations in said two-dimensional CD-profile, and   patterning a workpiece with said two-dimensional dose compensation profile.   
   
   
       9 . A method to compensate for process variations when printing a pattern on a workpiece, said method comprising:
 predicting a two-dimensional CD profile in said pattern to be printed on said workpiece,   generating a two-dimensional dose compensation profile to equalize fluctuations in said 2-dim CD-profile,   patterning the workpiece with said 2-dim dose compensation profile.   
   
   
       10 . An apparatus for process variation compensation when printing a pattern on a workpiece, said apparatus comprising:
 determining a two-dimensional CD distribution in said pattern printed on said workpiece,   generating a two-dimensional compensation file to equalize variations in said two-dimensional CD distribution, and   patterning a workpiece with said two-dimensional compensation file.   
   
   
       11 . A method of compensating for CD variations on a workpiece while printing a pattern on said workpiece, said method comprising:
 determining two-dimensional critical dimension (CD) variations associated with said pattern being printed;   estimating future CD variations of said patterning process;   compensating the dose while patterning said workpiece by pro-actively equalizing for said estimated CD variations; and   patterning said workpiece using said compensation of the exposure dose.   
   
   
       12 . An apparatus for compensating for CD variations on a workpiece while printing a pattern on said workpiece, said apparatus comprising:
 means for determining two-dimensional critical dimension (CD) variations associated with said pattern being printed;   means for estimating future CD variations of said patterning process;   means for compensating the dose while patterning said workpiece by pro-actively equalizing for said estimated CD variations; and   means for patterning said workpiece using said compensation of the dose.