The Plato Probe is a process compatible plasma measurement system, designed to work in deposition plasmas when an insulating film is deposited on the probe surface. This probe can remain inside a plasma reactor while highly reactive insulating gasses are in use. The Plato Probe measures plasma parameters such as plasma density, ion current density and electron temperature in plasmas with high deposition rates, like plasma enhanced chemical vapour deposition (PECVD). The Plato Probe has the most advanced patented technology on the market using ultra-fast biasing to penetrate the deposited film to obtain accurate measurements of the real plasma parameters in a wide range of plasma applications. The Plato Probe is used to establish plasma process repeatability, even in reactive gas plasma. It is the perfect instrument to understand plasma changes and the impact on surface treatment. The Plato Probe is an essential plasma process diagnostic to understand the correlation between plasma inputs and the plasma state in environments with a high rate of deposition.

1. PLATO | PROBE
“It is now possible for a Langmuir probe to
measure the uniformity of plasma
characterisations in plasmas with high
deposition rates, such as plasma enhanced
chemical deposition (PECVD)”

2. PLATO | PROBE
The Plato Probe is a planar
Langmuir Probe for deposition
plasma when an insulating film is
deposited on the probe surface.
The probe can remain inside a
plasma reactor while aggressive
insulating gasses are in use.
The Plato Spatial Probe scans
across the bulk of a plasma
using an automated linear drive
and measures the parameters at
different locations even when
depositing an insulating layer up
to 100 microns thick on the
probe surface.

3. PLATO | PROBE
Plasma Diagnostics Measured
Plasma Density • Ion Current Density
Electron Temperature
Measurement Functionality
Time Averaged • Time Resolved • Time Trend
Hardware
Electronics and Software
Voltage Scan Range: -40V to +40V
Current Range: 10μA to 100mA
Time Resolution: 1μS
Probes
300mm as standard (Custom available)
Chemically cleaned and replaceable
Spatial Movement
Automated linear drive with a 0.025mm step resolution
Vacuum Feedthrough
Available with KF, CF or custom vacuum connectors

4. PLATO | PROBE
Installation Setup
Plato Probe
Generator Match Plato
Electronics
Plasma Reactor
Computer

5. PLATO | PROBE
How It Works
The probe is biased with an AC
potential rather than the standard
DC potential
The AC bias couples through any
deposited layer
When the potential is negative it
collects ion current and when
positive it collects electron current
The AC current and voltage
waveforms are measured and used
to calculate the standard IV
characteristic
The IV characteristic is analysed in
the normal way

6. PLATO | PROBE
Typical Results
CCP Argon / 2Pa
Ne= 1.2x1015 m-3
Te= 2.3eV
As layer capacitance decreases,
RF voltage drop increases
10 Micron Layer
Solid Line 200kHz; Dashed Line 400kHz
0.00016
0.00014
0.00012
0.0001
0.00008
0.00006
0.00004
0.00002
0
-40 -30 -20 -10 0 10 20
-0.00002
-0.00004

7. PLATO | PROBE
Applications
As a probe for deposition plasmas, the Plato System assesses plasma
characterisations such as plasma enhanced chemical vapour deposition
(PECVD), plasma density, ion current density, & electron temperature in the
bulk of the plasma.
The Plato System can be used in the following applications:
Dusty Plasma
Plasma Etching
HiPIMS Plasma
PECVD
Space Plasma
Plasma Sputtering

8. PLATO | PROBE
For further information on the Plato Probe System visit
impedans.com/plato-spatial-probe
To request a quote visit
www.impedans.com/contact

9. Chase House
City Junction Business Park
Northern Cross
Malahide Road
Dublin 17
Ireland
Ph: +353 1 842 8826
Fax: +353 1 891 6519
Web: www.impedans.com
Email: info@impedans.com