Resist Resolution Enhancement and Line-end Shortening Simulation

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Resist Resolution Enhancement and Line-end
Shortening Simulation
SFR Workshop May 24, 2001 Mosong Cheng, Andrew
Neureuther Berkeley, CA
2001 GOAL to investigate the impact of
electric-field-enhanced post exposure baking on
resist profile validate resist/lens
aberration-based line-end shortening model by
9/30/2001.
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Motivation

• Line-End-Shortening becomes worse as device
  dimensions shrink to sub-100nm regime.
• Sources for Degradation of Pattern Fidelity
• Resist solution to short wavelength lithography

• Mask error
• Substrate reflection
• Recording media, in particular, undesirable acid
  diffusion/activation of resist
• Resist parameters vary from fab to fab
• Lens aberrations vary across field and from tool
  to tool

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ArF Imaging Modeling by Using Resist Simulation
and Pattern Matching
Mask Pattern
Imaging/Resist Simulator
Resist Profile
Differential
Resist Parameter Tuner
SEM Picture

• Optimizer is standard. The challenge is to build
  SEM/SIM comparator

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SEM/SIM Comparator
Contrast, Bright, Smooth, Edge
-
Moving window, threshold
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Aerial Image Simulation vs. Post Exposure Baking
Simulation
0.2mm
0mm
0.2mm
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Simulation Performance vs. Modeling Complexity
(170nm)
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Predictability of Models (120nm)
Imaging Model lt Base PEB Model lt Tuned PEB Model
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Electric-Field-Enhanced Post Exposure Bake

• Electric-Field-Assisted Top Surface Imaging a
  potential solution of resist to enable
  short-wavelength lithography. Generate acid at
  the resist surface, induce reaction in bulk
  resist by EFE-PEB.
• EFE-PEB applied to optical exposure

Resist
E
photoacid
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2002 and 2003 Goals
Investigate the impacts of the applied electric
field polarity, frequency and magnitude on post
exposure bake on e-beam and DUV exposure tools by
9/30/2002. Complete the resist/lens
aberrations-based line-end shortening model and
validate the simulation in 248nm and 193nm
lithography by 9/30/2002. Enable 3D EM simulation
of substrate topography effects by 9/30/2002.
Optimize the electric-field-enhanced post
exposure baking process by 9/30/2003.