High Rate low pressure PECVD for barrier and optical coatings

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1 High Rate low pressure PECVD for barrier and optical coatings, Matthias Fahland, John Fahlteich, Björn Meyer, Steffen Straach, Nicolas Schiller

2 Outline Introduction PECVD New developments magpecvd arcpecv D Examples Optics Barrier Outlook

3 Plasma enhanced CVD PECVD? CVD chemical vapor deposition Layer growth by chemical reaction at surface Layer material delivered by chemical compound precursor Energy transforms precursor into reactive species Plasma energy is used within PECVD Several by-products H 2 O CO 2 other low-molecular compounds Additional reactive gas suppliable 3

4 Why PECVD? Low temperature process Use of sensitive substrates like polymers Performs in vacuum Clean environment Broad choice of pre cursors and reactive gases Wide range of process parameters Power Frequency Pressure... 4

5 Outline Introduction PECVD New developments magpecvd arcpecv D Examples Optics Barrier Outlook

6 Magnetron based PECVD magpecvd Low pressure CV D (0.3 3 Pa) Driven by pulsed DC magnetron High coating rates (up to 400 nm m/min) Proven long-term stability over 8 h 6

7 magpecvd W ell-established plasma source Proven feasibility for large area applications Tuneable layer composition 7

8 magpecvd DC sputtering One hardware dual magnetron targets gas inlets Two processes magpecvd reactive DC sputtering 8

coating rates (> 2000 nm m/min) Tuneable layer composition

9 Hollow-cathode arc PECVD arcpecvd Low pressure CV D (0.1 5 Pa) Driven by hollow cathode arc plasma Very high coating rates (> 2000 nm m/min) Tuneable layer composition Combination with evaporation possible Organic modified coatings 9

10 arcpecvd coating rates Linearly dependent from pre cursor flow Increase with plasma power Increase with additional reactive gas flow 10

11 Plasma syst em for arcpecvd Very high plasma density Commercially available Designed for production Any web width through numbers of plasma sources Developed for large area applications 2,85 m 11

12 arcpecvd Plasma enhanced evaporation One hardware hollow cathodes gas inlets Two processes arcpecvd Plasma enhanced reactive evaporation 12

13 Comparison of PECVD methods magpecvd arcpecv D HF-PECVD MW-PECVD typical frequency process pressure coating rates remarks khz bipolar pulsed DC MHz 2.45 GHz Pa Pa 1 20 Pa Pa nm m/min nm m/min industrially proven for wide webs, units commercially available nm m/min nm m/min pressure range different to PVD Low pressure CV D Inline combination with PVD possible 13

14 Inline combination of PECVD and PVD R&D and pilot roll coater at FEP 600 mm coating width Multi-chamber design Available processes Sputtering (planar / rotatable) magpecvd Evaporation arcpecv D 14

15 Outline Introduction PECVD New developments magpecvd arcpecv D Examples Optics Barrier Outlook

16 Layer composition Precursor to reactive gas ratio adjustable Layer composition tunable HMDSO ratio low low carbon content inorganic SiO 2 -like layers HMDSO ratio high higher carbon content organic SiO x C y H z layers 16

17 Layer composition mechanical properties Increase HM DSO ratio Decrease of hardness Decrease of elastic modulus Increase in flexibility 17

18 Optical performance

19 Dielectric solar control layer st acks overall thickness approx nm SiO 2 made by infrared sputtering magpecvd 9 layers visible 19

20 Dielectric solar control layer st acks substrate curling due to layer stress nearly no layer stress 20

$Dielectric UV-mirror with magpecvd 20 layers HfO 2 high refractive index$

21 Dielectric UV-mirror with magpecvd 20 layers HfO 2 high refractive index 500 nm SiO 2 low refractive index high UV-reflectance high VIS-transmittance 21

22 Dielectric UV-mirror with magpecvd 20 layers Spectra measured across web width layer stack out of 20 single layers overall thickness approx nm highly uniform over 400 mm web width only 12 nm UV-edge shift across web width 22

23 Permeation barrier

24 Permeation barrier stacks Covering of layer defects by upper layers Surface smoothing Annealing of permeation barrier defects Increase of barrier performance Increase of mechanical robustness 400 nm 24

single layers Improved mechanical robustness 25

25 Permeation barrier stacks Inline made barrier stack 2 m/min web speed High barrier level comparable to single layers Improved mechanical robustness 25 Barrier 38 C, 90 % r.h. Sample size Ø100 mm

26 Permeation barrier st acks increased robustness Barrier layer Zinc-tin-oxid (ZTO) Interlayer SiO 2 made by magpecvd PECVD interlayers increase crack onset strain number of ZTO layers Layer stack more robust against mechanical deformation 26

27 Summary PECVD within multi-chamber PVD coaters Low pressure PECV D Designed for easy scale up Two options: magpecvd and arcpecv D One hardware multiple processes Optical coating stacks with nearly no layer stress Permeation barrier stacks with increased mechanical robustness Further development work Qualification for further pre cursors Adaptation to further industrial applications... Your application? Where can we work together? How can PECVD technology be integrated into your facilities? 27

28 Acknowledgement Essential results were obtained in several public projects, funded by Free State of Saxony, Federal Ministry of Education and Research and European Union 28

29 Thank you for your attention for barrier and optical coatings Fraunhofer FEP Winterbergstr Dresden Germany

From Vacuum to Atmosphere and back an in-house Process Chain for Different Products

From Vacuum to Atmosphere and back an in-house Process Chain for Different Products Dr. Steffen Günther Vacuum coating low pressure 10-1 10-4 Pa (10-3 10-6 mbar) unhindered particle movement no unintended