Download High efficiency RF matching network for ICP sources in

High efficiency RF matching network for
ICP sources in industrial applications
Dr. Rudolf Beckmann (Manz Coating GmbH)
Dr. Roland Gesche, Joachim Scherer (Aurion Anlagentechnik GmbH)
4th Power Electronics for Plasma Engineering Conference
Hüttinger Freiburg, May 28-29, 2013
Introduction
Why aren´t ICP sources not as widely used as CCP sources?
To get an answer we have to look at the following





Basics of CCP and ICP
ICP: H-Mode (inductive) versus C-Mode (capacitive)
Matching network circuits and efficiency
Experimental: How to distinguish H-/C- mode
Application in industrial environments
4th Power Electronics for Plasma Engineering Conference
Hüttinger Freiburg, May 28-29, 2013
Classification of RF discharges
(Kadetov 2004)
RF discharges can mainly be divided into CCP and ICP
 Less known is that also an inductive set up can act in capacitive mode!
4th Power Electronics for Plasma Engineering Conference
Hüttinger Freiburg, May 28-29, 2013
E-mode vs. H-mode
H-Mode
(no selfignition)
H-Mode
discharge
impossible
E-Mode
(Kadetov 2004)
An inductive antenna does not automatically produce a high density inductive plasma.
Pressure and power need to be chosen properly!
4th Power Electronics for Plasma Engineering Conference
Hüttinger Freiburg, May 28-29, 2013
E-mode vs. H-mode
H-Mode
(no selfignition)
H-Mode
discharge
impossible
E-Mode
(Singh 2004)
(Kadetov 2004)
An inductive antenna does not automatically produce a high density inductive plasma.
Pressure and power need to be chosen properly!
4th Power Electronics for Plasma Engineering Conference
Hüttinger Freiburg, May 28-29, 2013
Standard matching network for ICP
C2
RF
Generator
LAntenna
C1
RAntenna + Plasma
A highly efficient matching network can easily be built L-shaped.
However, the asymmetry could cause inhomogeneous plasma density.
How can it be made symmetric?
4th Power Electronics for Plasma Engineering Conference
Hüttinger Freiburg, May 28-29, 2013
Symmetric matching network for ICP
(Rayner 1996)
Using a transformer, galvanic separation and symmetry are achieved.
However, the use of a transformer reduces the efficiency.
Losses of 30% or even more are typical.
How could “high efficiency” and “symmetry” be combined?
4th Power Electronics for Plasma Engineering Conference
Hüttinger Freiburg, May 28-29, 2013
Symmetric and high efficiency
matching network for ICP
C1
RF
Generator
Antenna
C2
C3
Plasma
C4
(DE202012007227U1)
Using capacitors, the transformer can be avoided.
Symmetry is created through innovative circuit design.
4th Power Electronics for Plasma Engineering Conference
Hüttinger Freiburg, May 28-29, 2013
Symmetric and high efficiency
matching network for ICP
Simulations show that nearly
symmetrical operation can be
achieved by properly dimensioned
capacitors:
|U1/U2| = 0.99
 = 161°
A principal phase error of
approx. 20° remains due to R1
What is the benefit of this
matching network design in
practical applications?
4th Power Electronics for Plasma Engineering Conference
Hüttinger Freiburg, May 28-29, 2013
Practical application:
Efficiency of the matching network
3000
transfomer based version
Aurion (2012)
2500
50%
reduction
of losses!
loss [W]
2000
1500
1000
500
0
0
1000
2000
3000
4000
5000
6000
7000
8000
9000
10000
HF-Power Input [W]
The innovative matching circuit drastically improves efficiency.
Standard transformer technology produces up to 2600 W losses!
 higher energy consumption, higher cost for RF generator and components,
increased risk of not reaching the high density ICP mode
4th Power Electronics for Plasma Engineering Conference
Hüttinger Freiburg, May 28-29, 2013
Practical application:
Efficiency of the matching network
defined
Ion energy
8E-07
ICP Mode:
single energy
high dense plasma
7E-07
5 Pa
2,5 kW
5 KW
7,5 kW
10 kW
6E-07
I
dI/DV
5E-07
4E-07
3E-07
CCP Mode:
various energies
low dense plasma
2E-07
V2
1E-07
0E+00
0
5
10
15
20
25
30
35
40
measure current by increasing retarding V2
retarding Voltage [V]
Using sophisticated measurement techniques,
it can be shown that “real” ICP mode is reached.
4th Power Electronics for Plasma Engineering Conference
Hüttinger Freiburg, May 28-29, 2013
Practical application:
Efficiency of the matching network
8E-07
8E-07
5 Pa
5 kW
7E-07
2,5 kW
5 KW
7,5 kW
10 kW
6E-07
7E-07
6E-07
5E-07
5E-07
dI/DV
dI/DV
1.0 Pa
2.0Pa
5.0Pa
8.0 Pa
4E-07
4E-07
3E-07
3E-07
2E-07
2E-07
1E-07
1E-07
0E+00
0E+00
0
5
10
15
20
25
30
35
40
0
5
10
15
retarding Voltage [V]
CCP -> ICP by increasing
RF power!
Ion energy increases with
increasing RF power!
20
25
30
35
retarding Voltage [V]
CCP -> ICP by decreasing
pressure!
Ion energy increases with
decreasing pressure!
4th Power Electronics for Plasma Engineering Conference
Hüttinger Freiburg, May 28-29, 2013
40
Practical application:
Manz VCS 1200
Al2O3, Si3N4, other processes
High rate: > 6 nm/s
Excellent uniformity: < +/- 2%
over 330 x 330 mm² (2 sided)
Start Video
4th Power Electronics for Plasma Engineering Conference
Hüttinger Freiburg, May 28-29, 2013
Conclusion
Why aren't ICP sources not as widely used as CCP sources?
•
It is important to understand the different operating modes of
ICP sources and to take proper measures to ensure operation in
high density mode.
•
For that a high efficiency matching network in combination with
a well-designed ICP source and processing system are
required.
•
Then the advantage of ICP can be utilized in industrial
applications.
4th Power Electronics for Plasma Engineering Conference
Hüttinger Freiburg, May 28-29, 2013