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1
Chapter 7
2
CVD
3
CVD PVD
4
? ?
5
?
6
() ()
ni = ne ()
= ne/(ne + nn)
ne:ni:
nn:
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0.01% (High density plasma ,HDP) 15%
~100%
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()
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(Radio frequency, RF)
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e- + A A+ + 2 e-
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e- + A A* + e-
A* A + h ()
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h
h
h:
:
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e- + AB A + B + e-
CVD
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A B
e-
B
e-A
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()
CF4 (F)
e + CF4 CF3 + F + e
4F + SiO2 SiF4 + 2O
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CVD ()
PECVDSiH4 N2O ()e + SiH4 SiH2 + 2H + e
e + N2O N2 + O + e
SiH2 + 3O SiO2 + H2O PECVD
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21
(Mean Free Path, MFP)
n21
=
n
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MFP
(a) ( b)
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(MFP)
:
, MFP
, MFP
1p
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Q & A
?
(760 Torr)MFP
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me
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RF
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(Thermal Velocity)
v = (kTe / me)1/2
RF , Te 2 eVve 5.93107 cm/sec = 1.33107 mph
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:F = qvB
(Gyro-motion)
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mqB=
31
= v/
v
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, E
f(E)
2 - 3 eV
,
:200 - 400C
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, PECVD
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(Sheath Potential)+-+-+-+-+-+-+
+-+-+-+-+-+-+
+-+-+-+-+-+-+
+-+-+-+-+-+-+
+-+-+-+-+-+-+
+-+-+-+-+-+-+
+-+-+-+-+-+-+
+-+-+-+-+-+-+
+-+-+-+-+-++
++-+-+-+-++
++-+-+-+++
+++-+-+++
+++-++++
+++++++
Vp
Vf
x
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(flux)
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Vol
t
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RF
0
0
RF
RF
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13.56MHz
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()
Vp = 10 20 V
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()
0
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()
V2
A2
A1
V1/V2 =(A2/A1)4
V1 (V1-V2)
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IC : PECVD(CVD)
CVD
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CVD
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PECVD LPCVD
LPCVD (150 mm) PECVD (150 mm)
SiH4+ O 2 SiO2 + SiH4+ N2O SiO2 +
p =3 Torr, T=400 C p=3 Torr, T=400 C and
RF=180 W
100 to 200 /min 8000 /min
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HDP-CVD
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HDP CVD
0.25 m, 4:1
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PECVD
CVD:
: ,
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PECVD
1-10 Torr 1020 eV
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PECVD
RF
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(RF ): 200 to 1000 eV (): 10 to 20 eV
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(E-chuck)
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(< 100 mTorr) MFP,
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CVD
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O2 H2O
/
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H2O, O2
OO H
H2O, CO2,
O O OH H
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LOCOS STI
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CVD
()
NF3
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NF3
F FF
F N2N2F
CVD
N2, SiF4,
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CVD (RPCVD)
, SiO2, SiON, and Si3N4(High-): TiO2, and
Ta2O5 PMD
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MFP
CVD //
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(mTorr)
MFP
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70
ICP and ECR
(Inductively coupled plasma, ICP) (Transformer coupled plasma,
TCP)
(Electron cyclotron resonance, ECR)( mTorr)
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(ICP)
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(ICP)
73
74
ICP
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(ECR)
(Gyro-frequency) (cyclotron frequency)
mqB=e
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(ECR)
MW = e,
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ECR
B
78
ECR
ECR
79
ECR
80
n = n+
MFP
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PECVD
ICP ECR