ECE 654: Plasma Processing (tentative) Week 1-3: Introduction, dc Discharges, PDP/BLU Week 4-6: Waves, Transport, CCrf Disch. Week 7-9: ICP, Collisions Week 10-12: Global Modeling, NL Sheath Week 13-15: Etching, Diagnostics

Plasma Application POSTECH Introduction of PDP Present PDPs 1.5~2 lm/W High efficiency cell structure with low power consumption should be needed Energy Flow in PDP cell Future PDPs 5 lm/W

Investigation of Plasma Characteristics in a PDP Cell (a) t = 0.40  s (b) t = 0.70  s (c) t = 1.00  s Radiation transport in PDPStriation phenomenon anode cathode Pulse simulation anode cathode Xe ionElectron Ion angle distribution on MgO

Plasma Application POSTECH y x z z y x We can consider the 3-D effects of barrier rib and electrode shape. Examples of electrode shape 3-D Fluid Code for PDP (FL3P)

Ch.14. DC Discharge §14.1 (p.451) Def of Various Regimes of a dc normal glow PDP: neg glow only (~1lm/w) fluores. light: pos. glow (~70lm/w) §14.2 Positive Glow Column (s.s.) 1-D analysis ( ch.5 & same as for rf discharge. ch.10) (1)T e Improved eq. For T e (2) R cyl Eq. for T e s.s. Townsend arc

Ch.2 ◎ Kinetic Eqs & Equil.Maxwell Distr Distribution Function as averaged quantity from truly kinetic : A bit more continuum(averaged, coarse-grained) Defined only on phase space meshes Fluid: n(x i,t) define only on spatial meshes Boltzmann eq with an unclosed form of collision term L&L(2.3.3),Golant(3.17) -Kinetic Simulations Mol-Dynamics Sim Particle Sim(P-P) PIC (PIC/MCC;P 3 M;P-M) Vlasov sim(Boltzmann Sim) (Newtonian eqs)

Plasma Application POSTECH 12  Angle and energy dist. - Xe 5%, 300 Torr

Plasma Application POSTECH Xe 10% - Ne 90% Xe+ Ne+ El 13V A B Anode region 1 st bunch 2 nd bunch - Point B becomes the center region of next striation hump. - Potential difference between points A and B is about 13V. Striation issue (2)

Strong coupled ( P.E >> K.E. ) matter ( ie, solid ) Weakly coupled matter (ie, plasma, K.E.>>P.E. ) -Derivation of the Debye-shielded Potential

◎ T (eV) vs T(K) ◎ mmHg

J = 2.65  Langmuir Probe by Godyak  Thomson Scattering by Elsabbagh, Muraoka J = 3.8 mA/cm2  Using PIC-MCC Simulation J = 3.8 EEDF Comparison for a Small-Gap CCP

Fluid Eqs. & MHD Eqs. MHD eqs. 2-fl. Eq. -Fluid eqs.from Kinetic Eq. Taking 0 th moment of Eq. of Continuity 1st moment ofEq. of motion 2nd moment of Energy balance eq.

◎ Saha eq -F.chen: (T in °K, n in m -3 ) -Golant: (T in eV, n in cm -3 ) -Boulos: -Boltzmann statistics Thus

4mm Capillary tube, 15psi H2 4mm capillary tube, 15psi H2 After Neutral density filter 4mm Capillary tube, 15psi H2

L&L ch. 14 -Lamps, plasma display, BLU -Magnetron sputter, hollow cathode, PVD JK LEE (Spring, 2007)

14.3 Cathode Sheath : Vac. Breakdown ; Paschen Law(14.3.9) vbvb brkdn Ar Townsend 1 st Ionization Coeff. Breakdown or No-Breakdown (in simulation) 1)Ni or Ne increasing exponentially (faster than linear in t) 2)Ni > Nthr. ~ 3)The profile shapes of & Ni Meaning of brkdn nene t nene p z i e n e (z) E(z)/p Non-unif. ? Question:what’s needed to breakdown Ar? at P n = 1Torr, d =1 cm

Plasma Application POSTECH Necessity of Simulation Using various simulation codes (fluid, kinetic and hybrid codes) Research Objective  Suggestion of new PDP cell and pulse with high efficiency and its optimization  Study of plasma discharge characteristics  Comparison with experimental measurement Requirement of Simulation Limitation of experimental measurement in understanding the plasma dynamics (wall charge, potential, and excited species density distributions) Estimation and leading of research direction - Small system size (a few hundred  m) - Short discharge time (less than 1  s) 2-D Modeling of PDP cell using numerical simulation codes 3-D bus electrode dielectric ITO electrode MgO layer barrier phosphors address electrode Front panel Back panel

Plasma Application POSTECH Diagnostics of Fluid Simulation Density distributions Wall charge distributions Potential distributions anode cathode Light distributions

New PDP Cell Structures using Simulation 80 % 90 % 150 % 110 % conventional model

Plasma Application POSTECH Session 1 Flat fluorescent lamp for LCD backlight

Plasma Application POSTECH Display devices Emissive device Transmissive device TFT-LCDs need back-light unit (BLU) for light source!

EEFL By G.S.CHO CCFL EEFL Home LCD TV Flat Lamp [Year] Mercury-Free Lamps Qauntity (arbitary) Present Lamp (LCD) Industry Forecast (GS Cho)

e e e e e e e Thermionic electron emission (large tube, complex driving methods, short life) Ion-Induced electron emission (small & thin tube, simple driving, long life) Wall electron emission ( simple manufacturing & driving, long life) Hot Cathode F.L. : general lighting, long & large tubing Cold Cathode F.L. : LCD-BLU, Neon-Sign HID Lamp : Arc-Discharge : Outdoor, Automobile Electrode-less Lamps Inductive Coupled Discharge : QL lamp, Endura lamp (High Power, High Fr. Discharge) Capacitive Coupled Discharge : External Electrode F.L.(Low frequency)- Possibility of a new lamp. GS Cho

LOGO Y.S. Seo, S.M. Lee and J.K. Lee Department of Electronic and Electrical Engineering, POSTECH Plasma Application Modeling POSTECH LCD Backlight (Flat Fluorescent Lamp) 2006.

Xe* density distribution evolution (I) case4 reference (a) t =  s (b) t =  s Max. density 2.01E11 Max. density 6.68E11 Max. density 1.56E12 Max. density 6.42E12 (a) (b) (c) (d) (e) (f) (c)

Plasma Application Modeling, POSTECH Simulation results (I) (b) t =  s Max. density 6.43E12 (e) t =  s Max. density 6.41E12 168% 214%

Plasma Application Modeling, POSTECH Simulation results (II) 10mm 2mm 1.2mm 0.5mm 1.0mm 5mm1mm 1.5mm 0.5mm 168% 214% 228%

Plasma Application Modeling Group POSTECH LAPS Equipment(1,020mm  830mm  437mm) Stainless-steel Antenna Area for 2-D simulation Substrate 8 th generation flat panel (2.2X2.5 m); 7 th (1.87X2.2 m)

μ,

SUMMARY OF PLASMA WAVES (1)B O = 0 uncoupled (2) B O = 0 : coupled IA : hot electron –shield ion - wave (3) B o = 0 LH UH c s ~v i IA EC IC R L C IAW cscs w LH =210 wLwL vAvA W SA MS vAvA

The total ohmic power per length lost power radial loss only 1-D Thus (14.2.6) ( ) (discharge current, input)