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.
11/8/2000

2. 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).
11/8/2000

3. 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
11/8/2000

4. 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.
11/8/2000

5. RIAR: Rapid Imaging Algorithm for Resist (SPIE Microlithography’00)
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 STORM=O(N2)
CPU time of RIAR=O(N1.38)
For 625 nodes, STORM 3min, RIAR 20sec.
11/8/2000

6. 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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7. Calibrating Resist Model: Sim. Vs. Exp. II
l=193nm, NA=0.6, s=0.75, resist thickness=350nm, Real mask CD data were used.
11/8/2000

8. Applying the calibrated resist model to LES at the best focus
SEM picture
PROLITH simulation
11/8/2000

9. 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.
11/8/2000