( ) ( ) ( ) ( ) ( ) e - + Ar Ar + + 2 e - (1)
= = F d ( ) = q ε λ q ε λ q e - + Ar + Ar + hν (2) - - ( ) (Degree of Ionization) 0.1% 100% PECVD 1% PECVD (2) e - + Ar Ar + hν (3) Ar* 1 torr (q ε λ i ) (q ε λ e ) = 1/2mv 2 = 3/2kT ( ) (>100 torr) K
CVD PECVD Thermal CVD PECVD ( ) Townsend γ-ray γ-ray (
) Townsend Discharge 600V γ-ray Avalanche Discharge (Normal Glow Discharge) ( ) (Abnormal Glow Discharge) (Glow Discharge) (Thermal Emission Electron, ) (Arc Discharge)
1. (DC, Direct Current) (RF, Radio Frequency) (MW, Microwave) RF 13.56MHz MW 2.45GHz RF DC (coupled) DC RF MW RF DC RF MW MW ECR MW Helicon ECR (Wafer Damage)
2. PECVD CVD (Cold Trap) RF 3. 4.
5. (Base Pressure) (~10-5 torr) 0.1 (Ion Gauge) Pirani Gauge (Baratron) (Convectron) 6. Langmuir Probe ( ) OES(Optical Emission Spectroscopy)
(aspect ratio) Si (s) + 4F (g) SiF 4(g) SiO 2(s) + CF x (g) SiF 4(g) + SiF 2(g) +CO (g) +CO 2(g) +COF 2(g) +SiOF 2(g) +O 2(g) ~ - (Micro Electro Mechanical System, MEMS)
(Line of Sight Problem) Si F 2,CF 4 -O 2, C 2 F 6 -O 2,C 3 F 8 -O 2, SF 6 -O 2,SiF 4 -O 2, SiO 2,Si x N y, NF 3,ClF 3 SiO 2 III-V Si x N y SiO 2 SiO 2 TiS 2,TaSi 2, MoSi 2,WSi 2 SiO 2,Si x N y Si x N y 1:1 Ti,Ta,Mo,W, SiO 2 Nb TaO 2 Ta 2 N TaO 2,SiO 2,Al 2 O 3
Si CF 4, C 2 F 6 SiO 2, Si x N y CF 4, C 2 F 6, Si III-V C 3 F 8, CHF 3, CF 4 /C 2 F 6 -H 2, CH 4, C 2 H 2 /C 2 H 4 additions TiO 2, V 2 O 5 Ti V Si Cl 2, CCl 4, CF 2 Cl 2, SiO 2 CF 3 Cl, Cl 2 /C 2 F 6, Cl 2 /CCl 4, Br 2, CF 3 Br III-V Compounds Cl 2, CCl 4, CF 2 Cl 2, BCl 3 SiO 2, Al 2 O 3, Cr, CCl 4 /O 2, Cl 2 /O 2, Br 2 MgO Cl 2 Br 2 Al Cl 2, CCl 4, SiCl 4, BCl 3 Al 2 O 3 BCl 3, Cl 2 /CCl 4, Cl 2 /BCl 3, Cl 2 /CH 3 Cl, SiCl 4 /Cl 2 Cl 2 Ti, Br 2 1:1 vs CrO 2 at >20% Cr, Cl 2 /O 2 /Ar, CCl 4 /O 2 /Ar, O 2 Cr CrO 2, Au Cl 2 /Ar, CCl 4 /Ar C 2 Cl 2 F 4, Cl 2
(sputtering yield) (threshold energy) 10~30eV 100eV 70% 25% 2.2% ( chamber wall) (Magnetron sputtering) : m e Ve r = --(4) B q m e V e B q 1.6 10 19 (Coulomb) ( ) ( ) (Reactive sputtering deposition)
(a) (b)
(Plasma Enhanced CVD) 1. a. SiN Si 3 N 4 (Diffusion Barrier Layer) Thermal CVD Si 3 N 4 SiH 4 +NH 3 +N 2 700~1000 o C PECVD SiH 4 +NH 3 Si N PECVD 1. 2. 3. 4.RF 5. 6. 7. 8. Thermal CVD Si 3 N 4 Thermal CVD 900 o C PECVD 300 o C Si 3 N 4 Si x N y H z Si/N 0.75 0.8~1.0 (g/m 3 ) 2.8~3.1 2.5 2.8 2.0~2.1 2.0 2.1 6~7 6 9 (V/cm) 1 10 7 6 10 6 (Ω cm) 10 15 ~10 17 10 15 (dyne/cm 2 ) 1.2~1.8 10 10 1~8 10 9 (1/ o C) 4 10-6 4~7 10-6 >400 o C Thermal CVD PECVD Si 3 N 4 PECVD SiN 1. (Step Coverage) 2. 3. 4. 5. 6. b. SiO P-SiN SiH 4 +N 2 O
Thermal CVD PECVD SiH 4 + O 2 SiH 4 + N 2 O SiO 2 SiO x ±8% >±5% (1MHz) 4.0~4.4 4.6 1.48 1.54 (cm -2 ) 10~100 3 Thermal CVD PECVD SiO 2 2. (Reactive Sputtering) PVD (TiN) ( ) ( ) 3. (Plasma Polymerization) 1. 2. 3. (Cross Linking) 1. 2. 3.
RF RF Mi* + *Mi Mi Mi Mi* Mi* + M Mi M* Mi Mi* + *Mi* Mi Mk* *Mk* *Mk* + M *Mk M* *Mk* + *Mi* *Mk Mi* Mi (initial monomer) (Mi*) (*Mk*) (M) (Mi*) (*Mk*)
(High Density Plasma) 1% ICP ECR Helicon PIII (Inductively Coupled Plasma, ICP) (Inductively-Coupled-Plasma, ICP) RF 2-4 [42] RF power supply 5 H = J + ε 0 ( E/ t) --(5) E: (Volts/m) H: (Amperes/m) J: (Amperes/m 2 ) 6 E = - µ 0 ( H/ t) --(6)
(inductively coupling) (capacitively coupling) ( ) Fig. 2-4 The diagram illustrating the principle of inductively-coupled-plasma [42].
ICP (Electron Cyclotron Resonator, ECR) 1982 2.45GHz ϖ ce v V = R v v 2 mev v v v ebr = ev B V = R me v v Be ϖ Be v ce = ν ce = = 27.9922B( GHz) m 2π 2πm e e m e V B R ce
v ν ce = 2.45GHz B 875G B=875G 2.45GHz ECR (a) (b) Helicon Helicon helicon wave Helicon helicon wave (Collision damping) (Collisionless Laudau damping) Helicon Wave Helicon
Helicon Helicon
Lucas Signaton Vortex Helicon Etcher Helicon (MØRI TM Helicon Reactor)
(Vacuum Arc) / PIII (Plasma Immersion Ion Implantation) ( ) PIII (DC) (Spot) 100% ( Macroparticles ) 10-6 ~10-9 mm VAC
1% 90 o 90 o (Hollow cathode plasma) (Surface wave) (Helical Resonator)
1. B. N. Chapman, Glow Discharge Processes, John Wiley & Sons, 1980 2. J. L. Vossen, W. Kern, Thin Film Processes II, Academic Press, 1991 3. M. A. Lieberman, A. J. Lichtenberg, Principles of Plasma Discharges and Materials Processing, John Wiley & Sons, 1994 4. M. Konuma, Film Deposition by Plasma Techniques, Springer-Verlag, 1992 5.,,, 1995 6.,,,, 2000