![Page 1: Woodpile Structure Fabrication Chris McGuinness July 8, 2009 Workshop on Novel Concepts for Linear Accelerators and Colliders Working Group 2: Dielectric](https://reader030.vdocuments.us/reader030/viewer/2022032521/56649d5c5503460f94a3b044/html5/thumbnails/1.jpg)
Woodpile Structure Fabrication
Chris McGuinnessJuly 8, 2009
Workshop on Novel Concepts for Linear Accelerators and Colliders
Working Group 2: Dielectric Laser Accelerators
![Page 2: Woodpile Structure Fabrication Chris McGuinness July 8, 2009 Workshop on Novel Concepts for Linear Accelerators and Colliders Working Group 2: Dielectric](https://reader030.vdocuments.us/reader030/viewer/2022032521/56649d5c5503460f94a3b044/html5/thumbnails/2.jpg)
Outline
• Motivation
• Fabrication Process
• Fabrication Parameters
• Layer Adhesion
• Future Plans
![Page 3: Woodpile Structure Fabrication Chris McGuinness July 8, 2009 Workshop on Novel Concepts for Linear Accelerators and Colliders Working Group 2: Dielectric](https://reader030.vdocuments.us/reader030/viewer/2022032521/56649d5c5503460f94a3b044/html5/thumbnails/3.jpg)
Motivations
0
101
SiO2 Eacc=2.76 GV/m @800nm(3.75e5GHZ)
Si Eacc=337 MV/m @1550nm(1.94e5GHZ)
Al3O2 Eacc=2.0 GV/m @800nm(3.75e5GHZ)
ZnS Eacc=1.04 GV/m @5μm(6e4GHZ)
Ratio=1.41
GradientSources
Fabrication
![Page 4: Woodpile Structure Fabrication Chris McGuinness July 8, 2009 Workshop on Novel Concepts for Linear Accelerators and Colliders Working Group 2: Dielectric](https://reader030.vdocuments.us/reader030/viewer/2022032521/56649d5c5503460f94a3b044/html5/thumbnails/4.jpg)
4
3
wa
SiO2 resist
Silicon Substrate
Silicon Substrate
SiO2poly-si
Si Substrate
Photo resist
1
2
hSiO2
5
Poly-si
Fabrication ProcessStep 1: SiO2 Deposition - LPCVD
• Uniformity = 1-2%• Controllability = 7%
Step 2: Resist Coat
Step 3: Optical Lithography• Minimum feature size 450nm• Alignment 3σ=60nm
Step 4: Plasma etch SiO2
Step 5: Poly-si Deposition
![Page 5: Woodpile Structure Fabrication Chris McGuinness July 8, 2009 Workshop on Novel Concepts for Linear Accelerators and Colliders Working Group 2: Dielectric](https://reader030.vdocuments.us/reader030/viewer/2022032521/56649d5c5503460f94a3b044/html5/thumbnails/5.jpg)
Fabrication Process6
8
7
SiO2 poly-si
Time
Fric
tion
al F
orc
e
10sec=15nm
Step 6: Chemical Mechanical Polish
Step 7: Repeat process for remaining layers
Final Step: HF Vapor Etch
![Page 6: Woodpile Structure Fabrication Chris McGuinness July 8, 2009 Workshop on Novel Concepts for Linear Accelerators and Colliders Working Group 2: Dielectric](https://reader030.vdocuments.us/reader030/viewer/2022032521/56649d5c5503460f94a3b044/html5/thumbnails/6.jpg)
Four Layer Test Structure
![Page 7: Woodpile Structure Fabrication Chris McGuinness July 8, 2009 Workshop on Novel Concepts for Linear Accelerators and Colliders Working Group 2: Dielectric](https://reader030.vdocuments.us/reader030/viewer/2022032521/56649d5c5503460f94a3b044/html5/thumbnails/7.jpg)
Fabrication Deviations
Target Measured
Rod Width 500nm 498nm ± 74nm
Tapper Angle 0o 10.4o ± 0.6o
Layer Thickness 632nm 611nm ± 73nm
Alignment Offset <80nm 138nm
Parameter Summary
![Page 8: Woodpile Structure Fabrication Chris McGuinness July 8, 2009 Workshop on Novel Concepts for Linear Accelerators and Colliders Working Group 2: Dielectric](https://reader030.vdocuments.us/reader030/viewer/2022032521/56649d5c5503460f94a3b044/html5/thumbnails/8.jpg)
Tapper Angle
3.4o ~0o
6.6o
5.1oCHF3 85 sccmO2
6 sccm
CF4 50 sccmCH3F 20 sccmAr 100 sccm
CF4 50 sccmCH3F 25 sccmAr 120 sccm
P5000 -Magnetically Enhanced RIE
AMT 8100 - Hexode Plasma Etcher
CHF3 50 sccmO2
30 sccm
![Page 9: Woodpile Structure Fabrication Chris McGuinness July 8, 2009 Workshop on Novel Concepts for Linear Accelerators and Colliders Working Group 2: Dielectric](https://reader030.vdocuments.us/reader030/viewer/2022032521/56649d5c5503460f94a3b044/html5/thumbnails/9.jpg)
Rod Width
Measurement Resolution ~25nm
![Page 10: Woodpile Structure Fabrication Chris McGuinness July 8, 2009 Workshop on Novel Concepts for Linear Accelerators and Colliders Working Group 2: Dielectric](https://reader030.vdocuments.us/reader030/viewer/2022032521/56649d5c5503460f94a3b044/html5/thumbnails/10.jpg)
Layer Thickness
• Uniformity = 1-2%• Controllability = 7%
Oxide thick
Mean = 5769.0Min = 5656.6Max = 5861.2Std Dev = 68.524Uniformity = 1.1878 %
5861582757935759572556915657
Deposition – LPCVD TEOS
![Page 11: Woodpile Structure Fabrication Chris McGuinness July 8, 2009 Workshop on Novel Concepts for Linear Accelerators and Colliders Working Group 2: Dielectric](https://reader030.vdocuments.us/reader030/viewer/2022032521/56649d5c5503460f94a3b044/html5/thumbnails/11.jpg)
Layer Adhesion
![Page 12: Woodpile Structure Fabrication Chris McGuinness July 8, 2009 Workshop on Novel Concepts for Linear Accelerators and Colliders Working Group 2: Dielectric](https://reader030.vdocuments.us/reader030/viewer/2022032521/56649d5c5503460f94a3b044/html5/thumbnails/12.jpg)
Stress
![Page 13: Woodpile Structure Fabrication Chris McGuinness July 8, 2009 Workshop on Novel Concepts for Linear Accelerators and Colliders Working Group 2: Dielectric](https://reader030.vdocuments.us/reader030/viewer/2022032521/56649d5c5503460f94a3b044/html5/thumbnails/13.jpg)
![Page 14: Woodpile Structure Fabrication Chris McGuinness July 8, 2009 Workshop on Novel Concepts for Linear Accelerators and Colliders Working Group 2: Dielectric](https://reader030.vdocuments.us/reader030/viewer/2022032521/56649d5c5503460f94a3b044/html5/thumbnails/14.jpg)
Annealed WaferHF Vapor Etch
Not Annealed, Vapor HF Etched
Not Annealed, Buffered HF Etch Annealed, Buffered HF Etch
Annealed, Vapor HF Etch
![Page 15: Woodpile Structure Fabrication Chris McGuinness July 8, 2009 Workshop on Novel Concepts for Linear Accelerators and Colliders Working Group 2: Dielectric](https://reader030.vdocuments.us/reader030/viewer/2022032521/56649d5c5503460f94a3b044/html5/thumbnails/15.jpg)
Measure Adhesion Strength
......
![Page 16: Woodpile Structure Fabrication Chris McGuinness July 8, 2009 Workshop on Novel Concepts for Linear Accelerators and Colliders Working Group 2: Dielectric](https://reader030.vdocuments.us/reader030/viewer/2022032521/56649d5c5503460f94a3b044/html5/thumbnails/16.jpg)
Future Direction
• Complete 15 layer structure• Optical measurements
– Spectroscopy– Coupling– Mode excitation
• Beam measurements– Wakefield modes
• Simulations– Consider fabrication variations– Couplers
![Page 17: Woodpile Structure Fabrication Chris McGuinness July 8, 2009 Workshop on Novel Concepts for Linear Accelerators and Colliders Working Group 2: Dielectric](https://reader030.vdocuments.us/reader030/viewer/2022032521/56649d5c5503460f94a3b044/html5/thumbnails/17.jpg)
THE END
![Page 18: Woodpile Structure Fabrication Chris McGuinness July 8, 2009 Workshop on Novel Concepts for Linear Accelerators and Colliders Working Group 2: Dielectric](https://reader030.vdocuments.us/reader030/viewer/2022032521/56649d5c5503460f94a3b044/html5/thumbnails/18.jpg)
FTIR Spectroscopy Measurements
![Page 19: Woodpile Structure Fabrication Chris McGuinness July 8, 2009 Workshop on Novel Concepts for Linear Accelerators and Colliders Working Group 2: Dielectric](https://reader030.vdocuments.us/reader030/viewer/2022032521/56649d5c5503460f94a3b044/html5/thumbnails/19.jpg)
Finite Thickness Simulation
Reflection/Transmission(averaged over S&P polarizations, and polar angle θ, φ=0)
![Page 20: Woodpile Structure Fabrication Chris McGuinness July 8, 2009 Workshop on Novel Concepts for Linear Accelerators and Colliders Working Group 2: Dielectric](https://reader030.vdocuments.us/reader030/viewer/2022032521/56649d5c5503460f94a3b044/html5/thumbnails/20.jpg)
Simulation
Reflection/Transmission(averaged over S&P polarizations, and polar angle θ, φ=0)
![Page 21: Woodpile Structure Fabrication Chris McGuinness July 8, 2009 Workshop on Novel Concepts for Linear Accelerators and Colliders Working Group 2: Dielectric](https://reader030.vdocuments.us/reader030/viewer/2022032521/56649d5c5503460f94a3b044/html5/thumbnails/21.jpg)
Simulation vs. Measurement
Bandgap from MPB