Part 4 – Process Effect, Calibration / Correction

Speaker:

Richard Bojko, Ulrich Hofmann - GenISys GmbH

Takeaways:

• 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