plasma sensor for next generation plasma processing - · pdf fileplasma sensor for next...
TRANSCRIPT
Plasma Sensorfor Next Generation Plasma Processing
1. Why plasma sensor ? Prof. Hideo SUGAI ( Chubu University )
for easy control of plasma
New tool for plasma diagnostics !
Nanotechnology LCD PanelLSI Mobile-phoneDVDMEMS Carbon Nanotube
Plasma TelevisionBio-technology
You can easily monitor plasma density !
For Research & Development / Volume Production Line
Wide Range of MeasurementFrom low density (108 cm-3) to high density (1012 cm-3 )From low pressure to High pressure (~10 Torr)
All kinds of reactive gases for deposition and etching
Highly sensitive measurement of density change (∆~1%)
Usable ProcessesEtching, CVD, Cleaning CCP, ICP, SWP, ECR, helicon
Usable Plasmas
High resolution of space and time, metal impurity free
2. Principle of plasma sensor
Network Analyzer
2a2b2 - 6 mm
d5 mm
PlasmaAntenna
Coaxial Cable
(GHz)Frequency0 1 2 3
Electron density can be determined byResonance frequency
Quartz
Quartz
Reflection plasma
Standing wave is resonantly excited when d = λ/4wavelength λ depends on plasma density.
d
Surface Wave
Incidence
Sending frequency-swept power,Displaying the reflected power
Electron density is measured by Surface Wave Probe
Reflection
Reflection
Ref
lect
ed P
ower
②PC/ Display①Sensor(Surface Wave Probe)
Process Chamber
Plasma③Main Frame
Network Analyzer(300 kHz – 3.8 GHz)
3. Application of plasma sensor to materials processing
4. Patent status & Patent owner contactPatent license is available.Patent No. : US6184623, US6339297,
US6744211Patent owner contact: Masaru OZAKI (JST)
Tel:+81-3-5214-8486e-mail: [email protected]
With increasing discharge power,plasma density increasesso that resonance frequency goes up !
0 1 2 3
Discharge Power
Frequency (GHz)
Ar 10 mTorr
0
0.5
1.0
1.5
0 100 200 300Discharge Power (W)
ICP/Ar 20mTorr
0
0.5
1.0
1.5
Ref
lect
ed P
ower
Res
onan
ce F
requ
ency
(GH
z)
Pla
sma
Den
sity
(101
1cm
-3)
Plasma density ofinductive RF plasma
370 W
490 W
700 W
2 dBResonance frequency gives plasma density (27 MHz, 2 kW)
(0.8 MHz, 2 kW)
RF Source
RF bias
20 mm
300 mm
Movable surface wave probe(2 mm diam.)
C4F8/02/Ar=11/8/400 sccm
RF bias
30 mTorrRadial position (mm)
00
150
2
4
6
8
10
12
14
Pla
sma
Den
sity
(10
10cm
-3)
Radial Distribution of Plasma Density
SiO2 Etching by Dual Frequency CCP
300 W
0 W
1200 WPlasma
Plasma sensor first time revealed the plasma density distribution.
0.5
0.75
1
1.25
1.5
68 70 72 74 76 78 80 82
1%
ne~3x1010cm-3
0
0.1
0.2
0.3
0.4
0.5
8 10 12 14 16 18 20 22
ne~2x109cm-3
1%
Inductive RF Plasma
0.5Torr, Ar 0.5Torr, Ar
How sensitive surface wave probe is !
Discharge Power (W)Discharge Power (W)
Res
onan
ce F
requ
ency
(GH
z)
Res
onan
ce F
requ
ency
(GH
z)
Plasma sensor enables monitoring 1 % change in plasma density.
Capacitive RF Plasma
Plasma Sensor