Testbed for Plasma-Wall and Etch Product Studies
9
5/24/2001 1 Testbed for Plasma-Wall and Etch Product Studies SFR Workshop May 24, 2001 Matthew Radtke, John Coburn, David Graves Berkeley, CA 2001 GOAL: Construction and testing of apparatus for etching and etch byproduct studies by 9/30/2001.
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Testbed for Plasma-Wall and Etch Product Studies. SFR Workshop May 24, 2001 Matthew Radtke, John Coburn, David Graves Berkeley, CA. 2001 GOAL: Construction and testing of apparatus for etching and etch byproduct studies by 9/30/2001. Motivation. - PowerPoint PPT Presentation
Transcript of Testbed for Plasma-Wall and Etch Product Studies
5/24/2001
1
Testbed for Plasma-Wall and Etch Product Studies
SFR WorkshopMay 24, 2001
Matthew Radtke, John Coburn, David GravesBerkeley, CA
2001 GOAL: Construction and testing of apparatus for etching and etch byproduct studies by 9/30/2001.
5/24/2001
2
Motivation
• Etch products often play major role in etch chemistry
• System designed to study role of etch products.
• Plasma and surface diagnostics combined.
• Model studies require data: system measures all
neutral and ionic species impacting surfaces.
• N2 and Ar/c-C4F8 plasma diagnostics reported.
5/24/2001
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Experimental Apparatus
5/24/2001
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Etch Chamber (side view)
5/24/2001
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DiagnosticsMeasured Quantity Measurement Diagnostic
pressure pressure gauge
radical and neutral densities quadrupole mass spectrometer
(appearance potential mass spectrometry)
ion composition quadrupole mass spectrometer
electron density Langmuir probe
electron energy distribution
(electron temperature)
Langmuir probe
plasma potential Langmuir probe
average neutral temperature optical emission
wall temperature thermocouple
* mass spectrometer measurements are at wall * Langmuir probe can measure profile
5/24/2001
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Illustration of Diagnostics:
N2 plasma
N2 plasma: potential vs. density
0
20
40
60
80
100
120
0.00 2.00 4.00 6.00 8.00 10.00 12.00
Gas Density (mT)
Pla
sma
Po
ten
tial (
V)
0.5mt
1mt
3mt
5mt
10mt
8 7 6 5 4 3 2 1
3510200.00
0.05
0.10
0.15
0.20
0.25
0.30
N+
/N2+
flu
x r
atio
Power (setting)
P(mT)
N2 plasma (N+/N2+ ion flux ratio)
8 7 6 5 4 3 2 1
351020
0E+00
2E+16
4E+16
6E+16
8E+16
1E+17
1E+17
1E+17
2E+17
N f
lux
power setting
p(mt)
N flux: N2 plasma
5/24/2001
7
F CF CF2 CF3 C2F4 C4F8
13
100
1
2
3
4
Neu
tral
Den
siti
es (
*10
12 c
m-3
)
P (mTorr)
Neutral Densities: Ar/c-C4F8 plasma
• Radical densities from APMS
5/24/2001
8
0.0E+00
2.0E+08
4.0E+08
6.0E+08
8.0E+08
1.0E+09
1.2E+09
1.4E+09
0 20 40 60 80 100 120 140 160 180 200
Ion Mass (AMU)
Ion
Nu
mb
er
De
ns
ity
(c
m-3
)
C4F7
C3F7C3F4
C3F5
C3F6C3F2
C3F3
C4F5
C2F5
C2 C2F
C2F2 C2F3
C2F4
CF3
F
C
CF
CF2
C3F
Ar
Ar**
* Morgan, L. (2000)
- theoretical C4F8 total dissociation cross section calculation
0
1
2
3
4
5
6
7
8
5 10 15 20 25 30 35 40
Energy (eV)
EE
PF
*10-8
(e
V-1
.5 c
m-3)
cro
ss
se
cti
on
(1
0-16 c
m2 )
1mT
3mT
10mT
xsect*
P(mTorr) <Te(eV)> kdiss(10-8cm3/s)
1 6.42 2.93
3 4.87 1.86
10 3.38 0.776
Ion Densities and Langmuir probe measurements:
Ar/c-C4F8 plasma
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2002-2003 Milestones
• Studies of plasma-wall interactions
(e.g. Si/O/Cl for gate/trench etch)
• Studies of new high-K and gate stack etching
(e.g. etch precursors, by-products, selectivity)
• Studies of plasma surface interactions
(e.g. N2 plasma: PET; NF3 plasma: elastomer)
