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AIMCAL CONFERENCE PRESENTATION: LAYER PROPERTIES OF HIPIMS SPUTTERED - - PowerPoint PPT Presentation
AIMCAL CONFERENCE PRESENTATION: LAYER PROPERTIES OF HIPIMS SPUTTERED - - PowerPoint PPT Presentation
AIMCAL CONFERENCE PRESENTATION: LAYER PROPERTIES OF HIPIMS SPUTTERED SILICON NITRIDE, ZINC TIN OXIDE, AND ITO October 2018 AIMCAL 2018 REPORT OUTLINE Introduction and Goals HiPIMS (or HPPMS) Test Equipment and Setup Test
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− Barrier coatings applied to polymer films are widely utilized to increase the lifetime of commercial products ranging from food packaging to OLED displays. − The best optically transparent barrier layers are stoichiometric films such as Silicon Nitride or ZnSnO that are free of defects that allow the migration of water vapor and
- xygen.
− The goal of this study was to compare the results of sputtered SiN films that were deposited on a R2R web coating machine using more common pulsed DC and HIPIMS power supply technology. − Measurements for performance included: ▪ Deposition rate ▪ Optical transmission ▪ WVTR
INTRODUCTION AND GOALS
October 2018 AIMCAL 2018
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INTRODUCTION: HIPIMS hip-V Power Supplies
1, 6, 10 and 20kW Unipolar / Bipolar Standard / Positive Voltage Reversal Can be stacked up to 80 kW Synchronized pulsing/bias Developed and produced by Viesca Engineering Founded 2004 Producer of high power pulsed power supplies for trains
HIPIMS power supplies with Positive Voltage Reversal Coating development Contract R&D On site process implementation Founded 2012 Located in Madrid, Spain
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INTRODUCTION: HIPIMS
- High peak powers (500-2000 W/cm2)
- Reasonable average power (up to 80kW)
- Low duty factors (0.5-5%)
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INTRODUCTION: HIPIMS
Active V+ Passive V+ No V+
Option to control the voltage reversal
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INTRODUCTION: HIPIMS
Ar+ Me+
- Ion acceleration from the target surface (0-1000 eV)
- Increase of plasma potential (bombardment of low V surfaces)
Me+
Negative Pulse Positive Pulse
Ei= E0 + Qe (Vplasma- Vsurface)
AIMCAL 2018 October 2018
Me+ Me+ Me+
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− The coFlex R2R coater at FEP was utilized for these experiments. − Position 23 was used as the deposition zone.
TEST EQUIPMENT AND SETUP
October 2018 AIMCAL 2018
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Schematic of the deposition zone: − Single rotatable magnetron was used with Si:Al target material. − Magnetrons are 1m in length. − Rotatable magnetron with Ti target was used as the anode. − Both unipolar pulsed DC and HIPIMS were utilized for comparison.
TEST EQUIPMENT AND SETUP
October 2018 AIMCAL 2018
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Target preparation: − The silicon target was provided by GfE Fremat. − The target had been used for previous experiments for the OPTIPERM program. − Thus, the target was first prepared by grinding the outer edges to reduce the arc rate for this experiment.
TEST EQUIPMENT AND SETUP
October 2018 AIMCAL 2018
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− Control of HIPIMS
TEST EQUIPMENT AND SETUP
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− Typical waveform − Note positive voltage reversal − Current is at a constant slope
TEST EQUIPMENT AND SETUP
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− Waveform capturing an arc event − Note: ▪ Change in current slope ▪ Switching response of power supply
TEST EQUIPMENT AND SETUP
AIMCAL 2018 October 2018
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− Silicon Nitride was chosen due to it being a relatively common material for optical and barrier properties. It also lacks a strong hysteresis curve so that this will not be a strong influence on test set-up and results. − The power level was chosen to be 4-5 kW to avoid thermal issues due to high power.
TESTING OVERVIEW
October 2018 AIMCAL 2018
Parameter HIPIMS Unipolar Pulse Frequency 1.5 kHz 50 kHz Pulse on time 55 µs 15 µs Discharge voltage 760 V 400 V Maximum current 100 A 10 A Power 4 kW 4.5 kW Argon flow 200 sccm 200 sccm Nitrogen flow 0 – 70 sccm 0 – 70 sccm
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− Current comparison ▪ HIPIMS is independent of nitrogen flow ▪ Unipolar pulsed increases with nitrogen flow ~ 10%
TESTING OVERVIEW
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− Transmission of HIPIMS is higher for relative Nitrogen flow − The top of the curve was not discovered
TEST OVERVIEW
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− A conductive ceramic ZnSnOx target from GfE Fremat was tested. − Almost transparent when sputtered with Argon and more transparent with additional
- xygen gas.
− Ability to sputter at higher power – 9.5 kW with less concerns related to arcing. − A comparison of the waveforms between HIPIMS and Unipolar pulsed:
OTHER MATERIALS – ZINC TIN OXIDE
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Summary of deposition parameters
OTHER MATERIALS – ZINC TIN OXIDE Parameters HIPIMS Unipolar pulsed Frequency 1.5 kHz 50 kHz Pulse on time 30 µs 15 µs Peak Voltage 1000 V 1100 V Voltage Discharge 760 V 351 V Max Current 400 A 26.7 A Power 9.5 kW 9.5 kW DDR 37 nm*m/min 55 nm*m/min Argon flow 200 sccm 200 sccm Oxygen flow 10 sccm 10 sccm
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Summary of HIPIMS deposition parameters: − Lowest diffusion rate was with HIPIMS − Barrier properties seem to be low at lower film thickness − Deposition rate approximately 67% of unipolar pulsed DC
OTHER MATERIALS – ZINC TIN OXIDE
Look up published data for comparison
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− A Soleras target composition of 95% Indium Oxide and 5% Tin Oxide was utilized − Only an small amount of additional oxygen is needed for optimum film performance
OTHER MATERIALS - ITO Parameter HIPIMS Unipolar Pulsed Frequency 1.4 kHz DC Pulse on time 40 µs 15 µs Discharge Voltage 700 V 319 V Max Current 200 A 15.4 A Power 5 kW 5 kW DDR 22 nm*m/min 25 nm*m/min Argon flow 200 sccm 200 sccm Oxygen flow 3-9 sccm 3-9 sccm
Huh?
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− A Soleras target composition of 95% Indium Oxide and 5% Tin Oxide was utilized − Only an small amount of additional oxygen is needed for optimum film performance
OTHER MATERIALS - ITO
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− Note that the hysteresis curve is shifted
OTHER MATERIALS - ITO
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− Deposition rate is lower for HIPIMS than p-DC. ▪ Approximately 67% − SiN ▪ The transmission of HIPIMS is higher for relative Nitrogen flow. − Need data on higher flows… − ZnSnO ▪ Barrier performance shows an improvement for a specific thickness. ▪ Approximately 0.011 vs. 0.046 g/m2/day for 150 nm thick layer. − ITO ▪ Results seem to be comparable, but at a reduced oxygen flow. ▪ Need to confirm thickness for resistivity.
CONCLUSIONS
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− FEP: Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology ▪ Matthias Fahland ▪ Tobias Vogt − Nano4energy ▪ Ivan Fernandez ▪ Frank Papa
A SPECIAL THANK YOU TO:
AIMCAL 2018 October 2018
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