Part 3 – PEC Parameter Optimization


Doc Daugherty, Nezih Ünal - GenISys GmbH


  • 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