Bias Power Supply for TV and Monitor TFT LCD Panels. (Rev. E)
Large Area Sputter Deposition for Metal Oxide TFT...
16
External Use Large Area Sputter Deposition for Metal Oxide TFT Applications using Rotary Cathode Technology Marcus Bender R&D PVD Display Applied Materials FPD International China, Beijing September 11 th , 2013
Transcript of Large Area Sputter Deposition for Metal Oxide TFT...
External Use
Large Area Sputter Deposition for Metal Oxide TFT Applications using Rotary Cathode Technology
Marcus BenderR&D PVD DisplayApplied MaterialsFPD International China, BeijingSeptember 11th, 2013
External Use
Trends in Display Technology
2
New Requirements for Backplane Performance
Ultra High Resolution
Ultra Large Displays
High Refresh Rate (3D)
Low Power Consumption
Slim BezelDesign
Uniform and Stable, High Mobility TFT with simple
Structure and lowManufacturing Costs!
OLED TV
External Use
Excellent Cooling, Low SurfaceTemperature, Enabling high DR
No Nodule FormationNo Redeposition Zones
Rotary Target Technology
3
High Material Utilization
New 80%
Racetracks
Rotary Target
TU ~ 80%
Tmax ~ 80°C
AKT PiVotTM
External Use
Uniform IGZO: Ion Bombardment ControlµPCDMura free IGZO
External Use
Excursion: Oxygen Ion Bombardment
5
Reactive Sputtering• Oxygen creates energetic
and highly directional ionbombardment locallychanging layer propertiesduring growth
Bombardment Directions• O- Ions always leaving the target
surface perpendicular• Planar: No control of directions,
changing with target lifetime• Rotary: Geometry constant, no
change over lifetime
Tominaga, Thin Solid Films 1999
TOF: Dominant Species O- Ions
De Gryse, Thin Solid Films 2012
O- Ion Trajectories: Planar vs. Rotary
1m betweenDetector andSource
External Use
PiVot: Ion Bombardment Control
Split sputter mode (SSM)– Superposition of two sinusoidal
profiles
Minimize Bombardment Impact (large angle, reduced energy)
6
Perfect wobbling (PW)– Magnet movement sweeps
plasma across substrate
Widely spread Bombardmentexposure across substrate
Two Concepts for unique Magnet Motion in PiVot:
External Use
µPCD: Correlations with IGZO TFT
7
Reported direct correlation between µPCD measurement and TFT performance (by Kobelco)
μ-PCR (peak reflectivity signal) proportional to the carrier densityand carrier mobility
μ-PCD lifetime is characteristic to the recombination process of carriers, depending on quality of the IGZO
correlation with TFT stability expected Kobelco, APL 2011
µPCR
TFT
External Use
Uniform IGZO: Tuning µPCR profilesTwo routes towards more uniform reflectivity profiles
8
Ion Bombardment Control• Energetic oxygen ion
bombardment locally increasingmicrowave reflectivity
• Magnet movement improving asdepo non-uniformities
• PiVot can eliminate targetimprints
IGZO Post Annealing• As depo non uniformities in µPCR
can be reduced by annealing
µPCR 4.8% after annealing
4.7% THK uniformity
External Use
Uniform IGZO: Gen8.5 horizontal µPCD scans
9
Both, lifetime and amplitude homogeneity significantly improving byapplying and optimizing magnet movement
Unif. ≈ 40% Unif. ≈ 20%
Unif. < 5% Unif. ≈ 10%
Local Unif. ≈ 16% Local Unif. ≈ 12%
Local Unif. << 5%Local Unif. << 5%
OptimizedMagnet
Movement
No Magnet Movement
External Use
Mura Free IGZO from PiVot
10
Two kinds of mura known from PVD IGZO deposition
Target Pitch Mura• Reported Vth differences with
correlation to target positions forcompetitor system
Bond Gap / Target Tile Mura• No increase in peak reflectivity in
front of bond gap area• Data shows no target tile mura for
IGZO rotary targets
2x IGZO rotary target at 60% Utilization
Arai, Sony Corporation, SID 2012
Minimized Vth differencebetween and in front of target
Mura free IGZO Backplane
4 TFTs foreach position Bond gapBond gap
External Use
Stable IGZO TFT: PVD Al2O3 performance
External Use
Significant Stability Improvement of IGZO TFT reported
Challenges: Low deposition rate, slow etch
PVD Al2O3: Advanced Barrier Layer
12
Arai, Sony Corporation, SID 2010
External Use13
StatusThickness 150 -1000 ÅThicknessuniformity
± 9.0%(Gen 8.5, wobbling)
Breakdownvoltage
~ 2-3 MV/cm
Density 3.1-3.2 g/cm³Deposition rate 100-150 Å/minRefractiveIndex @ 550 nm
1.59 – 1.7
Uniformityrefractive index
~ ± 1 %(Gen 8.5, wobbling)
WER (DHF) 40~140 Å/min(depends on pO2)
PVD Al2O3 Performance Gen8.5
tunif = +/- 9.0%
n550nm = +/- 1.1%
External Use
ConclusionIGZO TFT emerging as a-Si replacement for high resolution mobile applications and large scale high definition LCD and OLED TVs
Rotary target technology combined with unique magnet movement enable uniform PVD IGZO deposition
TFT performance uniformity, especially Von, suitable for LCD andOLED applications
Fully reactive Al2O3 process with metal-like uniformity achieved withrotary target array
14
External Use
AcknowledgementsSpecial Thanks to:
Evelyn ScheerAndreas Klöppel
Jian LiuHyun Chan Park
Rodney LimDong Kil YimHarvey You
Hao-Chien Hsu
and everybody contributing to AMAT Metal Oxide progress around theglobe
15
