Extreme Ultra-Violet Lithography
Extendibility of EUV Lithography
Technology
for Semiconductor Devices
Jinho Ahn
Professor, Materials Science & Engineering, Hanyang University
Director, Nano & Convergence Tech., National Research Foundation of Korea
Moore’s Law
- Number of transistors on a chip doubles
every two years.
October 15, 2013
10th U.S.-Korea Nano Forum, Boston, MA
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Scaling Enabler: Lithography
October 15, 2013
10th U.S.-Korea Nano Forum, Boston, MA
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Wavelength Reduction has been
a key Driver of Moore’s Law
October 15, 2013
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Lithography Roadmap:
EUVL is the leading Lithography Technology
for 22 nm node and Beyond (2012 ITRS)
October 15, 2013
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What is Extreme UltraViolet (EUV)?
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 Last region of electromagnetic spectrum to be developed
 Cause atomic resonance leading to high degree of absorption in all materials
 Short l enables to see small structures and to write smaller patterns
October 15, 2013
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Why EUV Lithography ?
- Image quality with affordable k1 value
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Why EUV Lithography ?
- Cost Effective !
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Big Change of Optical System
from DUVL to EUVL
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Off-axis reflection optics
On-axis diffraction optics
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EUV Lithography Overview
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Wavelength-dependent defectivity
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Wavelength-dependent defectivity
Ref.. Mochi, Proc. SPIE 7636 (2009).
Penetration depth of different wavelength
Ref.. Goldberg, EUVL Workshop (2010).
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EUV Coherent Scattering Microscope
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Simple structure
- Minimizing imaging limit caused by objective lens
- Collecting diffaction pattern by CCD pixel
- Mask image reconstruction by reverse Fourier
Transformation
Simulation capability for various exposure conditions
- Incident angle and illumination condition
- Real actinic imaging capability with current and
future EUV scanner conditions
Ordinary microscope
Field Spectrum
Objective lens
Incoherent
Source
CSM
Aerial image
NA
CondenserReticle
Coherent
Source
Computer
Aerial
image
Ref. Dong Gun Lee
NA
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10th U.S.-Korea Nano Forum, Boston, MA
CSM with HHG EUV source @HYU
Collaboration with Samsung, FST & Auros
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Mask Imaging Results by CSM
25nm
32nm
Contact hole (honeycomb)
30nm
L/S horizontal
25nm
Contact hole
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L/S vertical
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CSM can detect low-density carbon
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contamination effect
Technology
Hanyang University
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15
Korea EUVL R&D Infrastructure
Co-workers:
Academia - POSTECH, SNU, SKKU, Inha Univ.
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Research Institute – Pohang Accelerator Laboratory, NCNT
Industry - Samsung Electronics, SK HynixDongjin Semichem, IMT
Seoul
Pohang
▷ beam size at mask : <φ 2mm
▷ energy range : 92.5 eV(13.4nm)
▷ energy resolution : > ±1%
Beamline
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Micro exposure Tool PR Out-gassing
EUV Microscope
10th U.S.-Korea Nano Forum, Boston, MA
EUV Reflectometer
9 EUVL
years K-EUVL
program
and Infrastructure
Beamline
& Tools
AIMS
Pohang Synchrotron Facilities
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Reflectometer
Resist Outgassing
Mask stage
Micro Exposure Tool
CSM / ICS
AIMS
Resist Outgassing
Reflectometer
Folding Mirror
S. C. optics
MET
Wafer stage
CSM/ICS
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10th U.S.-Korea Nano Forum, Boston, MA
1
Industry roadmap toward <10nm
Lithography supports shrink
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Ref: ASML
October 15, 2013
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Scanner Roadmap Extendibility
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Ref: ASML
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10th U.S.-Korea Nano Forum, Boston, MA
High-NA Limiting Factor
– Mask structure
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The 3D nature of the EUV mask limits resolution and image quality
New mask structure including re-designed reflector and thin absorber
is needed for high-NA system.
October 15, 2013
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Optimizing Mask Structure for high NA
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– New reflector and absorber
Ref: J. Ahn et al. 2013 EUVL Symposium
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Att.-PSM for better imaging quality
Circular
Dipole
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Very thin absorber for fine patterning
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October 15, 2013
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Conclusion
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Even though struggling from the source power problems, huge
progress is going on to insert EUV lithography into mass
production.
Further innovation is underway to extend EUVL resolution limit
beyond 10nm.
Continuing trend of device scaling will be realized though EUV
lithography.
October 15, 2013
10th U.S.-Korea Nano Forum, Boston, MA
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October 15, 2013
10th U.S.-Korea Nano Forum, Boston, MA