Analysis of carbon contamination on EUV mask using CSM/ ICSAnalysis of carbon contamination on EUV mask using CSM/ ICS
Jae Uk Lee1 , Chang Young Jeong1 , Sangsul Lee1, Jong Gul Doh1, , Dong Geun Lee2, Seong-Sue Kim2, Han-Ku Cho2, Seung-yu Rah3
and Jinho Ahn1
• Mask Contamination/Inspection System – Concept of system – Optical design – CSM image
• Carbon contamination analysis – EUV reflectivity change – Influence of carbon contamination
• Summary
Outline
inspection/review infra structure
2. Long term reliable source operation with 200W at IF
3. Resist met RLS simultaneously
4. EUVL manufacturing integration
2008 1. Long-term source
2. Defect free masks through lifecycle & inspection/ review infrastructure
3. Resist met RLS simultaneously
4. Reticle protection during storage, handling and use
5. Protection/ illuminator optics and mask lifetime
2007 1. Reliable high power
source & collector module
3. Availability of defect free mask
4. Reticle protection during storage, handling and use
5. Protection/ illuminator optics and mask lifetime
EUVL Critical issue - development target
EUV symposium 2009
AIMS : 2008 2nd setup
Resist evaluation system : Run / 2006 4th setup
11B EUVL(Hanyang U.)
Pohang Light Source
EUVL test bed - Infrastructure
-Coherent Scattering Microscopy/ In-situ Contamination System
1 : 11B EUVL
In-situ monitoring of mask contamination
2.CSM / ICS system
EUVL test bed
Field Spectrum Reconstructed Aerial Image
Field spectrum mask image reconstruction wafer aerial image
- actinic CD measurement, mask defect inspection
Introduction of CSM
Mask pattern imaging position
Mass Spectroscopy
optics chamber
Enable to test imaging performance of EUVL mask with carbon contamination
: In-situ imaging
CSM/ICS system
Optical design of CSM/ICS
X-ray CCD camera : Pixel - 2048 X 2048 imaging array Pixel size – 13.5 X 13.5 um2
Imaging area – 27.6 X 27.6 mm2
Vacuum compatible
CSM image
12.5nm (wafer scale) node EUV mask CD & H-V bias measurement possible! mλ=dsinθ Distance between pattern∝1/d
10th order diffraction 125nmL/S (wafer scale)
Vertical Horizontal
Absorber
CD repeatability
Reference Mirror
sample sampleRef
sample sampleRef 3.16 nA 3.32 nA
sample Ref
EUV mask
Photo diode current for Acceleration test
Optical microscope image of carbon after 2hr acceleration
200um
Carbon contamination analysis
A to
m ic
w ei
Influence of carbon contamination
RMS Roughness Before : 0.20nm
32nm L/S (wafer scale)
25nm L/S (wafer scale)
22nm L/S (wafer scale)
CSM image for evaluation
Test mask for evaluation of carbon contamination effect on imaging
Contamination analysis using CSM
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R e fle c tiv ity
Reference
Contaminated
- 28nm node contact hole image reconstruction
- CD repeatability < 1 (3σ)
and measure performance of EUV mask
Analysis of carbon contamination on EUV mask using CSM/ ICS
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