Resist Resolution Enhancement and Line-end Shortening Simulation

1
Resist Resolution Enhancement and Line-end
Shortening Simulation
SFR Workshop November 8, 2000 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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Electric-Field-Enhanced Post Exposure Bake

• Vertical electric field enhance the vertical
  drift/oscillation of photoacid, improve resist
  profile uniformity, reduce lateral acid
  diffusion.
• Al plates were coated a film to prevent
  electrochemical reaction
• E AC component and an upward DC component (to
  reduce T-topping).

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Electric-Field-Enhanced vs. Standard Post
Exposure Bake
UVIIHS. 0.3, 0.2, 0.1mm L/S, 12mC/cm2. PEB 140oC,
90s. Dev. 60s. EFE-PEB AC 9.8V, DC 0.65V, 3Hz.
EFE-PEB
E
EFE-PEB
E
Standard
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Electric-Field-Enhanced vs. Standard Post
Exposure Bake
EFE-PEB, 200nm CD
Standard, 200nm CD
EFE-PEB, 300nm CD
UVIIHS. 0.3mm L/S, 9mC/cm2. PEB 140oC, 90s. Dev.
60s. EFE-PEB AC 9.8V, DC 0.65V, 3Hz.
5
RIAR Rapid Imaging Algorithm for Resist (SPIE
Microlithography00)

• Assume 2-D reaction/diffusion. Parabolic
  polynomials are applied to approximate the
  solution.
• Time evolving scheme Iterative solve the
  polynomial coefficient until the error reaches
  certain criteria.

CPU time of STORMO(N2) CPU time of
RIARO(N1.38) For 625 nodes, STORM 3min, RIAR
20sec.

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Line-End Shortening Calibrating Resist Model
based on Pattern Fidelity
Base model
Tune chemically amplification coefficient
Tune dissolution parameters
Tune PEB diffusivity
PROLITH simulation
2D image
SEM image
Differentiator
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Calibrating Resist Model Sim. Vs. Exp. II
l193nm, NA0.6, s0.75, resist thickness350nm,
Real mask CD data were used.
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Applying the calibrated resist model to LES at
the best focus
SEM picture
PROLITH simulation
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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. Optimize the electric-field-enhanced
post exposure baking process by
9/30/2003. Complete the resist/lens
aberrations-based line-end shortening model and
validate the simulation in 248nm and 193nm
lithography by 9/30/2002.