Rotatable Magnetron Sputtering in R2R Web Coating of Optical 2018-10-08آ  Rotatable Magnetron Sputtering

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  • Rotatable Magnetron Sputtering in

    R2R Web Coating of Optical Layer Stacks

    Holger Proehl, Martin Dimer, Michael Hentschel, Falk Otto, Johannes Struempfel

    VON ARDENNE Anlagentechnik GmbH, Dresden

    Oct. 2013, Charleston

    http://www.aimcal.org/events/web-coating-handling-conference-usa.aspx

  • VON ARDENNE Expertise Main Product Lines for Large Area Coating

    Oct. 2013 VON ARDENNE - AIMCAL Web Coating & Handling Conference 2013 - Charleston

    for glass coating for glass coating

    for large-area glass coating

    for metal strip coating

  • Oct. 2013 VON ARDENNE - AIMCAL Web Coating & Handling Conference 2013 - Charleston

    Rotatable Magnetron Sputtering in R2R Web Coating of Optical Layer Stacks

    Outline • Rotatable Magnetron Sputtering • AC Sputtering of Dielectric Films

    • SiO2 Sputtering (Impedance Control) • TiO2, Nb2O5 Sputtering (Ceramic)

    • DC Sputtering (TCO) • Aspects of ITO Sputtering

    • Sputter Roll Coater for Polymer Films • Process Flexibility • Concepts of Compartment Units

    • Summary

  • Rotatable Magnetron Process in DC or AC Mode Overall Advantages

    Oct. 2013 VON ARDENNE - AIMCAL Web Coating & Handling Conference 2013 - Charleston

    • Lower running costs  Better target usage (≥ 85% compared to ≤ 40% for planar targets)  Longer sputter campaigns  Higher deposition rates (higher max. power due to direct cooling)

    • Better process performance and stability  No re-deposition zones  less particles, less arcing  No cross contamination by sputtering of target clamps  Easy adjustable magnetic fields

    planar rotatable

  • Oct. 2013 VON ARDENNE - AIMCAL Web Coating & Handling Conference 2013 - Charleston

    Rotatable Magnetron Sputtering in R2R Web Coating of Optical Layer Stacks

    Outline • Rotatable Magnetron Sputtering • AC Sputtering of Dielectric Films

    • SiO2 Sputtering (Impedance Control) • TiO2, Nb2O5 Sputtering (Ceramic)

    • DC Sputtering • Aspects of ITO Sputtering

    • Sputter Roll Coater for Polymer Films • Process Flexibility • Concepts of Compartment Units

    • Summary

  • Coating Technology – Process in AC Mode Rotatable Dual Magnetron (RDM)

    Oct. 2013 VON ARDENNE - AIMCAL Web Coating & Handling Conference 2013 - Charleston

    AC/MF + + - -

    AC Conductive targets (ρ ≤ 1 Ωcm), conductive and insulating layers long-term stable processes (e.g. ZnO, SnO2 or Si3N4)

  • Low Index Material SiO2 Silicon Target with Reactive AC Sputtering

    Oct. 2013 VON ARDENNE - AIMCAL Web Coating & Handling Conference 2013 - Charleston

    Planar with Re-deposition | Rotatable w/o Re-deposition Flaking  Maintenance | w/o Nodules less Maintenance

    • Si planar target, • Target thickness10mm • AC power density < 15 kW/m • ddr = 50 nm*m/min per SDM • Cleaning of target periodically • Severe re-deposition, flaking

    • Si rotatable target, • Target thickness 9mm • AC power density ≈ 20 kW/m • ddr = 140 nm*m/min per RDM • Clean target, minor maintenance • No flaking, no nodules

  • Working Ranges for High Rate Reactive Sputtering

    Oct. 2013 VON ARDENNE - AIMCAL Web Coating & Handling Conference 2013 - Charleston

    metallic mode

    reactive mode

    transition mode stabilization

    by fast control of reactive gas flow,

    only

    • Hysteresis for power P = constant

  • Reactive AC Sputtering of SiO2 Characteristics of O2 Flow vs. AC Voltage

    500V 500V

    Oct. 2013 VON ARDENNE - AIMCAL Web Coating & Handling Conference 2013 - Charleston

  • Voltage Fed for Stabilization Working Points – Simple Control Scheme –

    Oct. 2013 VON ARDENNE - AIMCAL Web Coating & Handling Conference 2013 - Charleston

    PID controlled gas inlet

    Sputter Process Power

    Supply controlled

    voltage

    Gas manifold

    Power setpoint

    Slow control loop τ ~ 1 min

    Fastest control loop, dependent on power supply, typ. τ ~ ms range

    Target Voltage setpoint

  • Reactive AC Sputtering of SiO2 O2 Flow vs. Power, @ 500 V (no Hysteresis)

    Oct. 2013 VON ARDENNE - AIMCAL Web Coating & Handling Conference 2013 - Charleston

    • Increased flow @ constant voltage   Current / power increase  Dep. rate increase

  • Voltage Fed Working Point Stabilization – Gas Trimming –

    Oct. 2013 VON ARDENNE - AIMCAL Web Coating & Handling Conference 2013 - Charleston

    Target

    Pumping speed at target end influenced by chamber geometry

    Sputter rate slightly different due to deviations in target geometry (B-field strength varies with distance)

    • 5 Segmented fast acting gas inlet manifold  Tuning of deposition rate homogeneously  Tuning of reactive gas pumping locally  Same reactive working points at all sites of target

  • 0

    50

    100

    150

    200

    250

    240 250 260 270 280 290 300

    dd r/M

    AG (n

    m *m

    /m in

    )

    Lambda Voltage (mV)

    Rate SiO2

    ddr/MAG (nm*m/min)

    Flow Mode

    Reactive AC Sputtering of SiO2 Partial Pressure Control (λ-probe)

    • Dependency of deposition date (AC-MF) on lambda probe voltage Uλ

    Oct. 2013 VON ARDENNE - AIMCAL Web Coating & Handling Conference 2013 - Charleston

    absorbing

    oxydic Only with process control

  • Reactive AC Sputtering of SiO2 Partial Pressure Control: λ-probe

    • Lambda Probe is an galvanic cell  Cell voltage = lambda voltage Uλ  Nernst Formula:

    Uλ ~ const. * ln {pO2(ambient)/pO2(process)}

    Oct. 2013 VON ARDENNE - AIMCAL Web Coating & Handling Conference 2013 - Charleston

    Pr oc

    es s g

    as

  • Reactive AC Sputtering of SiO2 Partial Pressure Control (λ-probe)

    • Dependency of cathode (AC) voltage and O2 Flow on Uλ

    Oct. 2013 VON ARDENNE - AIMCAL Web Coating & Handling Conference 2013 - Charleston

    0

    100

    200

    300

    400

    500

    600

    700

    800

    240 250 260 270 280 290 300

    U m

    f ( V)

    Lambda Voltage (mV)

    SiO2-Voltage Voltage C44.4…

    Flow Mode

    0

    100

    200

    300

    400

    500

    600

    240 250 260 270 280 290 300

    f(O 2)

    [s cc

    m ]

    Lambda Voltage (mV)

    Oxygen - flow FlowO2 avgFlow Mode

    absorbing

    absorbing

    Addition of some N2 may be necessary to stabilize the process control at aggressive working points.

  • Reactive AC Sputtering of SiO2 Segmented Fast Gas Inlet System

    Oct. 2013 VON ARDENNE - AIMCAL Web Coating & Handling Conference 2013 - Charleston

    Unpressurized  minimized amount of gas pV: pressure @ Volume

    Fast Binary Manifold with 5 Segments

    for fast response and precisely controlled gas inlet with minimized stored amount of gas

    MFC 1 MFC 5 MFC 2 MFC 3 MFC 4

  • Oct. 2013 VON ARDENNE - AIMCAL Web Coating & Handling Conference 2013 - Charleston

    Rotatable Magnetron Sputtering in R2R Web Coating of Optical Layer Stacks

    Outline • Rotatable Magnetron Sputtering • AC Sputtering of Dielectric Films

    • SiO2 Sputtering (Impedance Control) • TiO2, Nb2O5 Sputtering (Ceramic)

    • DC Sputtering • Aspects of ITO Sputtering

    • Sputter Roll Coater for Polymer Films • Process Flexibility • Concepts of Compartment Units

    • Summary

  • High index Materials – Ceramic Targets Uniformity Examples from Production

    Nb2O5 • ddr up to 90nm*m/min w/o

    absorption • Example: RDM 3750 (AC)

    TiO2 • ddr ~ 55nm*m/min w/o

    absorption • Example: RDM 3750 (AC)

    Oct. 2013 VON ARDENNE - AIMCAL Web Coating & Handling Conference 2013 - Charleston

     Max. Deposition Rate is limited by max. applicable power (target / substrate) compare T. Preussner et al., Nb2O5 and TiO2 thin films deposited by pulse magnetron of cylindrical ceramic targets, ICCG9 (2012)

  • • ddr ~60nm*m/min • Tweb(max) ~ ?

    • ddr ~55nm*m/min • Tweb(max) ~ ?

    Ceramic TiO2: AC vs. DC Energy Impact at Substrate

    AC dual DC dual

    Oct. 2013 VON ARDENNE - AIMCAL Web Coating & Handling Conference 2013 - Charleston

    AC + _ + _

    substrate

    DC

    substrate

    +

    _ DC

    +

    _

    Assumptions: PET 50µ, Cooling drum: TCD = 0°C, heat transfer: α = 100 W/(m²K), 2m/min

  • • ddr ~58nm*m/min • Tweb(max) ~ 29°C

    • ddr ~55nm*m/min • Tweb(max) ~ 61°C

    Ceramic TiO2: AC vs. DC Energy Impact at Substrate

    AC dual (RDM) DC dual (RSM-RSM)

    Oct. 2013 VON ARDENNE - AIMCAL Web Coating & Handling Conference 2013 - Charleston

    Assumptions: PET 50µ, Cooling drum: TCD = 0°C, heat transfer: α = 100 W/(m²K), 2m/min

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