Part 4 – Process Effect, Calibration / Correction


Richard Bojko, Ulrich Hofmann - GenISys GmbH


  • What is the “Base Dose” for most stable process
  • Process calibration procedure with TRACER
  • Effective Short-Range Blur including process effects
  • Lateral development effect and density dependent bias
  • Limitation of Optimum Contrast for thick low contrast processes
  • HSQ process effects

Summary of the Webinar:

  • “Real” processes have many effects beyond electron scattering
    • Process / metrology bias
    • Lateral development from finite resist contrast (density dependent)
    • Additional midrange process effects
      • PEC Dose Range depends on
  • Resist contrast: consequence of the iso-focal shift (image iso-focal -> process iso-focal)
    • High-contrast requires Diso/Ddense = 1 + 2*BS/FS, one PMMA required Diso/Ddense = 1 + 1.2*BS/FS
  • Additional midrange terms such as resist sensitivity changes (e.g. HSQ from catalytic reactions)
    • TRACER is adding an additional mid-range energy term on top of the electron scattering PSF
  • Maximizing the blur latitude important because
    • Shot size dependent focus shifts
    • Shot size dependent blur variability
  • This results in Uniform Clearing or mix factor strategies (substrate and resist contrast dependent)
  • Ability to play with parameters & see effects on process window
    • BEAMER can be used to correct for not only the “Proximity Effect” but also these additional process effects