Larger Area of Coverage
Balanced Ion
Long Life
No Overshoot
No Particulates or Air Flow
No Cleaning or Maintenance
No Ozone Generation
No EM Noise
Not Limited to Line of Site
No High E Fields Required
Distance: 1.1m
Diameter: 1.6m
Cross
Sectional Area: 1.2m2
Volume: 1.3m3
Carbon (2.26 g/cm2)
1mm – 10mm thick
Tra
nsm
issi
on
(%)
Silicon (2.33 g/cm2)
0.5mm – 0.75mm thick
http://www.engineeringtoolbox.com/water-vapor-air-d_854.html
N2, O2, H20, Ar(.0018 g/cm2)
0.1m – 1m thick
*1% water vapor at
65RH, 23C
Att
enu
ati
on
(%)
Pb, O, Si (4.36 g/cm2)
0.01mm – 0.1mm thick
SiO2, B2O2, Na2O (2.23 g/cm2)
0.1mm – 1.0mm thick
(C5O2,H8 )n (1.18 g/cm2)
1.0mm – 15mm thick
X-Rays pass through
materials ionizing the air
eliminating ESD on both
sides of the wafer
Sustaining near 0V ion
balance throughout chamber
because ionization is
occurring isotopically at the
same rate as recombination
Front Opening Unified
Pod
Air ionizer is limited to “line
of site” and dissipates ESD
only on one side of the wafer
AC pulse provides good ion
balance but at the sacrifice
of recombination & ion
mobility
ESD Volume Coverage
Pulsed DC
Corona
Photoionization
X-ray Penetration & Shielding
5keV 15keV 5keV 15keV
Eliminating High Static Voltage Quickly
150mm x 150mm charge plate voltage dissipation from +1000V to +100V over time and distance provides a 1 dimensional map of
‘decay time’ performance. Rotating over 360 degrees by assumed axial symmetry indicates volumetric coverage. Moxtek has the highest
performance and fastest decay over largest area of any photoinizer in the world due to proprietary X-ray technology.
Air ionizer vs. PhotoionizerE. Miller
Moxtek, Inc., Orem UT, U.S.A.
0.5 sec
1.0 sec
2.0 sec
f16mm
MOX-10 TOC
Static elimination range:
10.5kV / 0.5mA
(static air: 23C, 20%RH NTP)
Side by side performance capability shows X-ray have faster
decay time over a larger region. X-ray are limited only by the
1/dx2 factor rather than air flow or ion mobility, they are able to
ionize the air at greater distances and more uniformly than
typical corona
Long Distance Performance
Ionization energies (eV)
AMU 1st 2nd 3rd 4th 5th
N 7 14.5 29.6 47.4 77.5 97.9
O 8 13.6 35.1 54.9 77.4 113.9
Ar 18 15.8 27.6 40.7 59.8 75.0
O2 16 12.0
CO2 22 13.7
N2 17 15.9
Corona
X-ray Benefits
**Compressed Y-axis to ensure same scaling factors
Top View
Side View
bb
X-ray spectral output of photon energies from 2,500V – 12,500V shown below
allow for many Compton scatter events prior to not having sufficient energy to
ionize constituent air molecules. This method of ionizing continuously
throughout the entire air region mitigates much recombination factors involved
with ion loss.
X-ray ion balance is easily maintain because
photons are continually creating an even mix of
(+) ions, (-) ions and electrons across the entire
volume of air.
Close Distance Performance
The DC pulse corona alternates the field polarity. The field will mobilize the ions in
the direction of the field of opposite polarity. This causes the ions of opposite potential
near each other to recombine and naturalize their charges. This creates a region of
neutrality between the ion wave fronts reducing the overall effectivity of ESD on the
surface. When presented with a near surface, the air tubulation will further degrade
due to increased mix of ion. This was demonstrated in the DOE below. A comparative
of corona and X-ray decay rates as measured on a field probe near a glass plate.
Primary Photon
Primary Photon
The + wave form of the corona can be seen as the frequency on tope of the decay voltage signal
Equipotential surface
map of field gradient
of a corona source
Photonic path as simulated
with material interaction
modeling photoionization
and Compton scattering,
processes
g g
g
Air
Pulsed DC polarity
on HV alternating
the ion production
Ion wave front
mapping
2015 International Workshop
on the Physics of
Semiconductor Devices
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