Part 3 – PEC Parameter Optimization

Speaker:

Doc Daugherty, Nezih Ünal - GenISys GmbH

Takeaways:

• Detailed PEC parameter overview
• Selection of PSF
• Layer specific PEC
• PEC fracture optimization and minimize number of shapes
• Process loading and lateral development correction

Summary of the Webinar:

• Optimization of the layer for PEC
  • All (and only) pattern for exposure in the resist should be included
  • PEC is able to maintain layers
    • Use layer for writing order control
    • Use different layer (bulk/sleeve or coarse/fine) beam currents for combining accuracy and speed in one exposure

• The correction can be only as good as the correction function
  • Monte-Carlo simulated (table defined) PSF
  • Adding a mid-range “Gamma” process blur to Monte Carlo PSF
    • Some resist process effects (e.g. HSQ)
  • Definition of “Effective Short-Range Blur” for short-range correction

• Optimizing PEC accuracy vs. shape count
  • Define dose classes by % dose accuracy
    • Higher accuracy requires more dose classes, more shapes
  • PEC fracturing parameter, specifically minimum figure size (MFS) give control on the number of shapes
  • Selected layer can be excluded from LR fracturing or/and short-range correction

• Advanced Correction parameter and model
  • Lateral development can be corrected by a PSF-Density dependent Bias table (from experiment, or better TRACER calibration)
  • High density substrates with low contrast resists may require “Uniform Clearing” correction model, or a “Mix-Factor” between Optimum Contrast (OC) and Uniform Clearing (UC). The mix-factor may be calibrated by TARCER