Oct 12, 2010 - Andy Smith, STFC Daresbury Laboratory. Peter Doel, Carolyn Atkins, Hongchang Wang, David Brooks, and Alan Smith. Department of Physics ...
Outline •Introduction to MOAs:
Micromachining Optical Arrays
•Project context: The Smart X-ray Optics consortium •What are the MOAs and requirements
•MOAs iterations:
Camelia DUNARE, Bill PARKES, Tom STEVENSON
•Initial design •Spider design
•Conclusions and further work
October the 12th 2010, CAS Sinaia, Paper O2.2
October the 12th 2010, CAS Sinaia, Paper O2.2
Smart X-ray optics consortium members Peter Doel, Carolyn Atkins, Hongchang Wang, David Brooks, and Alan Smith Department of Physics and Astronomy, UCL Ady James, Graham Willis, Mullard Space Science Laboratory (MSSL) of UCL. Alan Michette, David Hart, Slawka Pfauntsch, Shahin Sahra, and Matthew Shand Department of Physics, King’s College London
•Introduction to MOAs
Tom Stevenson, Camelia Dunare, and William Parkes Scottish Microelectronics Centre, University of Edinburgh
Richard Willingale and Charly Feldman, Department of Physics and Astronomy, University of Leicester Andy Smith, STFC Daresbury Laboratory Tim Button, Dou Zhang, and Daniel Rodriguez Sanmartin IRC in Materials Processing, University of Birmingham
October the 12th 2010, CAS Sinaia, Paper O2.2
October the 12th 2010, CAS Sinaia, Paper O2.2
http://SmartXrayOptics.org
The Smart X-ray optics projects •Enhance performance of existing systems, such as X-ray telescopes
What are the MOAs?
•Micro-structured optical arrays (MOAs) for microfocus sources and X-ray microscopy.
•New active/adaptive X-Ray optics
Large scale SXO
Small scale SXO
bent MOA
curved MOA
•Use grazing incidence reflection through consecutive aligned arrays of channels
MOA •Bending the arrays allows variable focal length
1D focus •Actively controlled mirror systems
2D focus
•Flexing parts of the arrays provides adaptive or active systems
• array of channels etched in silicon
•Schematic of MOA
•Both use grazing incidence reflection October the 12th 2010, CAS Sinaia, Paper O2.2
October the 12th 2010, CAS Sinaia, Paper O2.2
Requirements for MOAs
•High aspect ratio devices •Vertical walls •20:1 aspect ratio •Smooth walls: roughness not to exceed 2nm
•MOAs iterations
•5cm radius of curvature
October the 12th 2010, CAS Sinaia, Paper O2.2
October the 12th 2010, CAS Sinaia, Paper O2.2
Dry etched MOAs
Dry etched MOAs Bosch Process
• Initial design • mask layout DRIE ICP 10 x 20 mm device
2x2 mm array
scribe channel
• 20µm and/or 10µm pitch
• single crystal silicon • 3”, , 380 µm thick, resistivity and type not important
• for etching • SF6, O2, Ar • for passivation • C4F8
October the 12th 2010, CAS Sinaia, Paper O2.2
October the 12th 2010, CAS Sinaia, Paper O2.2
Dry etched MOAs • 20µm pitch • 10µm pitch
Dry etched MOA’s
• Initial design
• Initial design
• scallops (800nm wide by 120nm high)
• Using overrun and ramping down the C4F8 • Dip-off in HF • Short thermal oxidation (1100oC) • Dip-off in HF • 20nm->8nm
• 40nm->20nm
• Ra~20nm
Aspect ratio 23.5:1
• aspect ratio 15-20:1
• 80nm->30nm
• Ra~40nm
• walls
