PRECISION OPTICAL FILTERS BY EOSS - ENHANCED OPTICAL SPUTTERING SYSTEM
EOSS ENHANCED OPTICAL SPUTTERING SYSTEM Fraunhofer IST, Braunschweig Contact: Dr. M. Vergöhl +49 531 2155 640
EOSS Coating System for Precision Optical Filters Motivation A coating system that offers stable and easy to use processes without complex process control combines the advantage of IBS processes (stability & quality) and evaporation (deposition rate & substrate size) is build for continued changes of designs to meet customer demands offers inherent long term stability produces clean and reproducible coatings
EOSS Coating System Setup
EOSS Sputter Coating System Key peformance Processes MF, RF sputtering, RF-plasma source CARS, Metamode, reactive Coating materials: SiO 2, Al 2 O 3, Ta 2 O 2, Nb 2 O 2, TiO 2, ZrO 2, HfO 2, easy to mix materials, metals Large area, fast rate: 12x200mm substrates Uniformity within ±0.15% Deposition rate: 0,6 nm/s Fully automatized production control: MOCCA +, BBM 360-1650nm
EOSS Coating System High volume coating system 12 carriers on turntable Substrate cabinet with 60 carriers (200mm diameter) Base pressure < 2x10-7 mbar Process temperature 300 C Handling and coating fully automatized
EOSS Coating System Improved coatings by applying cylindrical magnetrons redeposition zone racetrack transition area: source of particles No redeposition zone and no racetrack! Continuous and uniform erosion of the surface
EOSS Coating System Very clean process Processes #1-#5: Sputter down #3-#7: Rotatable #6: EOSS, SiO 2 #7: EOSS, 14 layer filter Particle contamination < 10 ppm
EOSS Coating System Extremely high uniformity Distribution of material within the direction of rotational motion Uniformity better than ±0,10 % transmission [1] 0,54-96 mm -84 mm -72 mm -60 mm 0,52-48 mm -36 mm -24 mm -12 mm 0,50 Zentrum +12 mm +24 mm +36 mm 0,48 +48 mm +60 mm +72 mm +84 mm +96 mm 0,46 780 785 790 795 800 805 810 wavelengt [nm]
EOSS Coating System Extremely high uniformity Distribution of material perpend. to the direction of rotational motion Uniformity better than ±0,15 % transmission [1] 0,54 0,52 0,50 0,48 0,46-96 mm -84 mm -72 mm -60 mm -48 mm -36 mm -24 mm -12 mm Zentrum +12 mm +24 mm +36 mm +48 mm +60 mm +72 mm +84 mm +96 mm 780 785 790 795 800 805 810 wavelength [nm]
EOSS Coating Examples Longpass filter 40 layer longpass filter with defined spectral edge Partial substrate coatings by handmade masks 100 transmission [%] 100 80 60 40 20 0 Sample #1 Sample #2 Sample #3 Sample #4 Sample #5 Sample #6 Sample #7 Sample #8 transmission [%] 80 60 40 20 0 50% @ 436,5 nm ± 0,3 nm substrates masked and positioned by hand Sample #1 Sample #2 Sample #3 Sample #4 Sample #5 Sample #6 Sample #7 Sample #8 430 435 440 445 450 Wellenlänge [nm] 400 500 600 700 800 wavelength [nm]
EOSS Coating System Notch filter OD6 notch filter (80 layers) Broad band transmission Excellent layer quality On 200 mm wafer Transmission [%] 1000 100 10 1 0,1 0,01 1E-3 1E-4 Filter Theory 1E-5 560 580 600 620 640 660 680 700 Wavelength [nm]
EOSS Coating Examples Filter for Laser 3D-projection, 60-80 layers 60-80 layer filter MOCCA + monitor 20 measurements on a 200mm wafer
EOSS Coating Examples AR Coating (time-controlled) Double side coating, 12 layers/side Reflectance [%] 100 80 60 40 20 Spec: R < 0.5% @ 400-700 nm 10 runs, 5 substrates 1,2 0 400 500 600 700 Wavelength [nm] Time control only 1,0 Extremely reproducible Thinnest layer < 6 nm r.m.s. thickness error < 0.1 nm reflectance [%] Very low particular 0,0 contamination 400 500 600 700 0,8 0,6 0,4 0,2 Batches #1- #10 (5 double sided coatings) wavelength [nm]
EOSS Coating Examples Laser clean-up filter 375 nm Specs: T avg > 90% 372 378 nm OD avg >5 bei 337-359 nm und 393-415 nm OD avg >3 bei 212-265 nm und 385-554 nm Fabricated without test run No AR on back side Transmission [%] 100 10 1 0,1 0,01 Transmission Design Target 1E-3 1E-4 200 300 400 500 600 Wellenlänge [nm]
EOSS Coating Examples Bandpass filter, wide blocking range 9 substrates with 200 mm diameter each Double side coating Spectra shown for 3different batches 3 different carriers Wavelength position Transmission (%) 1,0 0,8 0,6 0,4 0,2 0,0 within 0.25% (±0.125%) 400 600 800 1000 1200 1400 1600 Wavelength (nm)
EOSS Coating System Blended layers by co-sputtering Due to the layout of the coating system, co-sputtering in every sputtering mode is possible Virtually free tunable index of refraction between the materials Production of Rugate layers Stabilization of critical materials such as TiO 2, HfO 2 by doping with SiO 2 Filters created by mixed oxides presented at the Optatec 2012 in Frankfurt refractive index ( =550 nm) [1] 2,6 2,4 2,2 2,0 1,8 1,6 1,4 n( =550 nm) E G 0 10 20 30 40 50 60 70 80 90 100 fraction of SiO 2 in TiO 2 [%] 5,5 5,0 4,5 4,0 3,5 3,0 optical bandgap [ev]
EOSS Coating System Products & Application Optical filters ranging from single layers up to several hundred layers Steep edge Notch, Multinotch Bandpass Beam splitters High/Low reflection Polarizers Dielectric-metal-hybrid Chirped mirrors Rugate, Material mixtures Applications Analytics: e.g. fluorescence microscopy, raman spectroscopy, biomedicine, solar simulators, Laser based systems: e.g. reflectors, chirped mirrors, Coatings on sensitive substrates The system is build for continued changes of designs to meet customer demands
EOSS Coating System Full production automation by MOCCA + The MOCCA + kit includes 19 system rack Spectral range 360 1650 nm Accuracy < 0.3 nm (< 0.6 nm IR ) Light source: 50W halogen Optical fiber system Fast measurement interval: 1.6 ms Optilayer adapter
EOSS Summary High precision optical coating system based on magnetron sputtering and cylindrical magnetrons Fully automized Excellent layer quality Low absorption and scatter losses Dense and defect-free layers Rotatable magnetrons Excellent long-term stability with rotatable magnetrons Target lifetime up to 3 months - 24/7! Extremely high uniformity, virtually no drift (no racetrack)