1. 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.
5/24/2001

2. 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
5/24/2001

3. ArF Imaging Modeling by Using Resist Simulation and Pattern Matching
Mask Pattern
Imaging/Resist Simulator
Resist Profile
Resist Parameter Tuner
Differential
SEM Picture
Optimizer is standard. The challenge is to build SEM/SIM comparator
5/24/2001

4. SEM/SIM Comparator - Contrast, Bright, Smooth, Edge
Moving window, threshold
5/24/2001

5. Aerial Image Simulation vs. Post Exposure Baking Simulation
–0.2mm
0mm
0.2mm
5/24/2001

6. Simulation Performance vs. Modeling Complexity (170nm)
5/24/2001

7. Predictability of Models (120nm)
Imaging Model
< Base PEB Model
< Tuned PEB Model
5/24/2001

8. 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
5/24/2001

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.
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.
5/24/2001