SEMATECH's EUVL Mask Blank Defect Reduction Program: ML ...

Accelerating the next technology revolution 

SEMATECH's EUVL Mask Blank Defect 

Reduction Program: 

ML Deposition Defect Sources and 

Mitigation Strategies 

Frank Goodwin 1 , Toshi Nakajima 2 , Patrick Kearney 1 , 

Junichi Kageyama 2 , Vibhu Jindal 1 , Masahiro Kishimoto 2 , 

C.C. Lin 1 , Andy Ma 1 , Milt Godwin 1 , Jenah Harris-Jones 1 

1 SEMATECH 

2 AGC Electronics America 

Oct, 2010 

Copyright ©2008 

SEMATECH, Inc. SEMATECH, and the SEMATECH logo are registered servicemarks of SEMATECH, Inc. International SEMATECH Manufacturing Initiative, ISMI, Advanced Materials Research Center 

and AMRC are servicemarks of SEMATECH, Inc. All other servicemarks and trademarks are the property of their respective owners.

EUV Readiness 

• Mask blank defects are the single most critical EUV 

technology gap. 

• Blank development has not kept pace with roadmap, 

especially progress with the multilayer deposition process. 

– There had not been sufficient progress with EUV mask blank defect 

reduction in 2008-2009. 

• Defect Reduction Roadmap 

• To improve performance SEMATECH formed the EUV 

Mask Blank Defect Reduction Program. 

2010 International Symposium on Extreme Ultraviolet Lithography 

28 October 2010 2

EUV Mask Blank Defect Reduction 

Program 

• Mask Blank Development Center 

– MBDC Strategy 

• Establish a facility and expertise to support metrology and evaluation of 

EUV mask blanks. 

• Continue to develop world class expertise on metrology and 

characterization of small (sub-100nm) defects. 

• Provide facilities for blank suppliers to develop and evaluate new 

processes for multi-layer deposition and metrology. 

• EUV Multi-layer Deposition 

– Deposition Strategy 

• Generate the fundamental understanding of the ML deposition process 

and particle generation. 

• Demonstrate feasibility of IBD multi-layer deposition to meet mask blank 

pilot line defect and reflectivity requirements. 

• Enable a supplier to successfully build the next generation multi-layer 

deposition tool. 


28 October 2010 3

Approach to EUV Mask Blank Defect 

Reduction 

• Resources 

– Increased headcount 

– Task force mode for the past 12 months 

• Data driven decisions 

– Improved metrology for defect classification 

• FIB/SEM (defects > 100nm) 

• Auger (defects down to 30nm) 

• TEM (defects down to


28 October 2010 5

Defect Classification 

• Current metrology, energy dispersive spectrometry (EDS), on FIB/SEM 

– EDS elemental mapping recently implemented to extract more information 

on the composition of defects 

– Does not provide quantifiable composition analysis or information on 

chemical state of the defect 

– Limited ability to characterize small core defects and distinguish these from 

the background material. 

• Auger and TEM analysis capability is ramping to support analysis of 

small core size defects. 

– Auger analysis availability increasing as experience base increases 

• Processes are being developed for defects of sizes down to 30nm. 

– TEM analysis is ramping up 

• Sample prep work on-going 

• Greater resolution for elemental analysis – morphology, EDS + EELS, defects 

EDS improvements to FIB/SEM: 

Elemental mapping 

• EDS mapping implemented to extract more information from multi-layer 

defects 

– AlOx+SS re-classified as Al 

– Same As Background (SAB) reclassified a Si rich defect 


28 October 2010 7

Recent Auger Results 

• Defect analysis on substrate 

is particularly challenging due 

to the charging issues 

– A carefully controlled conductive 

coating has been implemented 

as a countermeasure. 

– The coating is thin enough to 

allow Auger electrons to escape 

while being be thick enough to 

dissipate surface charge. 

• Defect size down to 30 nm 

have been identified 

successfully (Close to the 

resolution limits of the tool) 


28 October 2010 8

TEM Analysis 

• TEM Firsts 

– A native substrate defect at 

50 nm lateral size and > 5nm 

high has been imaged. 

– Film deposition over the 

defect characterized. 

– A native substrate pit type 

defect has been has also 

been imaged and 

characterized. 


28 October 2010 9

TEM Analysis 

• TEM analysis of crystalline defect 

– This defect was determined to be crystalline Si originating from the Si 

target. 

– On-going work to create 3D tomography to determine how defects on 

target could have been formed. 


28 October 2010 10

Fundamental Learning of Deposition 

Process 

• What has been characterized 

– Ion Source characteristics 

• Ion beam energy 

• Flux 

• Distribution of ions 

– Target characteristics 

• Material composition 

• Crystallinity 

• What is currently being worked on 

– Deposition characteristics on substrate 

• Decoration of pits and particles under different deposition conditions 

– Ion-target interaction 

• How defects form on the target surface 

– Plume/Ions/Sputtered atoms scattering and motion inside chamber 

• Study of gas phase scattering and motion in order to determine 

deposition rates on different areas of the chamber (chamber walls and 

substrate area) 


28 October 2010 11

Characterization of the Deposition 

Chamber 

• Film deposition, temperature and stress were measured 

across the process chamber. 

– Size of blue circles indicates thickness of deposition 

• Large circle > greater deposition rate. 

– Size and color of circles indicate size and direction of stress. 

• Red is compressive, Green tensile. 

• Large circle > greater stress levels 


28 October 2010 12

Comparison of Simulation to 

Experimental Data 

• Simulation run with 100,000 each of Mo and Si atoms into 

1.4e-4 Torr Argon. 

• Model matches the experimental data. 


28 October 2010 13

Defect Composition per Substrate 

Si Family 

Defects 

Al Family 

Defects 

SAB 

SiOx 

Si 

AlOx 

AlOx+SS 

Other 

Defect 

Types 

Ru 

C 

0 1 2 3 4 

Average for all marathons 

M12 

M13 

• The advanced metrology and defect analysis capability 

enables development of a pareto graph by defect 

composition. 


28 October 2010 14

Targeted Defect Reduction 

Absolute defect count per plate 

20 

15 

10 

5 

0 

Si family defects 

Al family controbutin 

Handling contribution 

M5 M6 M7 M8 M9 M10 M11 M12 M13 

• Identification of the composition and source of the defects 

enabled a targeted approach to reducing defects. 

– Elimination or mitigation of defect source or defect type. 

– Influence of process changes and conditions. 

• Performance obtained on the IBD tool supporting AGC 

Electronics America pilot line at the SEMATECH/CNSE MBDC 

facility. 


28 October 2010 15 

Other 

Total defects

Defect Reduction Roadmap - Today 

• Over the past 12 months ML defects have been reduced from a average 

total defect level of 44 per mask-blank to a level of 18 defects per maskblank. 

Champion total defect results: 

• M1350@71nm: 6 defects 




Champion particle-type defect results: 

• M1350@71nm: 3 particle defects 




• Results were obtained in collaboration with our partner; AGC Electronics America 


28 October 2010 16

Defect Reduction Roadmap - Tomorrow 

defects/cm^2 @ 25nm 

sensitivity 

Jul-07 

15.7601 

Dec-07 

5.2534 

Dec-09 

3.9400 

Jul-10 

2.6267 

Dec-10 

0.5253 

Jul-11 

0.1051 

Dec-11 

0.0525 

Jul-12 

0.0210 

Dec-12 

0.0131 

Jul-13 

0.0053 

Dec-13 

0.0026 

# of defects (142X142 mm^2) 

@ 73 nm sensitivity 

120.98 40.33 30.25 20.16 4.03 0.81 0.40 0.16 0.10 0.04 0.02 

• Next Generation IBD Tool. 

– SEMATECH’s objective is to 

deliver a new tool concept by 

mid-2011. 

– Will likely be late 2013 before a 

new deposition tool will be 

available. 


28 October 2010 17

Defect Reduction 

• At SEMATECH, little progress in defect reduction demonstrated in 

2008-2009. 

• With a refocused effort a 60% improvement in the defect levels of EUV 

Mask Blanks has been demonstrated over the past 12 months. 

– Tremendous improvement in failure analysis and characterization 

methodology has provided key understanding of defect modes. 

– Strong correlation between simulation of deposition process and 

experimental results. 

– Modulation of defectivity signal is proven. 

– First substantive improvement in defect level since December 2007. 

• Next Generation IDB Tool. 

– Needed to meet EUV mask blank defect requirements for pilot line 

production. 

– Concept design is being developed. 

– First tool potentially available in late 2013. 

• The achievements were obtained with the collaboration with our partner 

AGC Electronics America 


28 October 2010 18

More Details – Associated Posters 

• “Deposition Process for EUV Mask Blanks” - Junichi Kageyama (AGC 

Electronics America) 

• “SEMATECH’s Infrastructure for Defect Analysis and Failure Analysis of 

Small Size EUV Mask Blank Defects to support EUV Mask Defect 

Reduction Program” – C.C. Lin (SEMATECH) 

• “Modeling growth of defects during multilayer deposition of EUV blanks 

by level set method” – Vibhu Jindal (SEMATECH) 

• “Low defect EUVL mask blank deposition tool process characterization 

and modeling.” – Patrick Kearney (SEMATECH) 

• "EUVL Mask Blank Defect Inspection Capability at SEMATECH" – Andy 

Ma (SEMATECH) 

• “Implementing Dual-pod Handling Capability on a Film Deposition Tool 

for Defect-free EUVL Mask Blank Development” – Jae Sohn 

(SEMATECH) 


28 October 2010 19

Acknowledgements 

• Lithography 

– Bryan Rice, Stefan Wurm, 

• MBDC 

– Anne Rudack, Jon Underwood, Tim Owen, Cecilia 

Montgomery, Kristy Maxwell, Mark Maloney, Ed Maillet, 

Nancy Lethbridge, Chip Lethbridge, Dan Kraft, Butch 

Halliday, Len Gwenden, Chris Cirigilano. 

• Cleans Group 

– Abbas Rastegar, Matt House 

• ISMI Metrology 

– Chris Deeb, Brad Thiel 


28 October 2010 20


28 October 2010 21

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