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With better than 1 ppm detection limit, direct sampling at mTorr
pressure, and a user-friendly Windows software package,
the CIS systems will satisfy your most demanding applications. On-line
process monitoring and control, verification of process gas purity
at the point of use, high-vacuum residual gas analysis, and process
equipment leak checking are some of the areas where these systems
will prove indispensable.
Compact Design
The probe consists of a quadrupole mass spectrometer with a CIS
ionizer mounted inside a 2.75" Conflat®
Tee. The control unit mounts directly on the probe’s feedthrough
flange and contains all the necessary electronics for operating
the instrument. The side port of the CIS nipple provides a connection
for the differential pumping system that keeps the quadrupole, filament
and detector
at high vacuum. The system can be connected directly to a process
chamber through its standard CIS mounting flange (2.75" CF).
The unit is self-aligning, with a simple, robust design. You can
clean and reassemble the probe, and replace the filament and electron
multiplier in the field, without ever calling the factory.
Gold Plated Ionizer
The entire ionizer is made of gold-plated stainless steel. This
reduces outgassing and background signals in the ionization region,
improves the long-term stability and permits
operation while exposed to reactive and corrosive
gases. A Tungsten filament is used, which resists corrosive and
reactive gases like WF6 and silane,
and leads to extended lifetime. The closed (gas tight) design of
the ionizer prevents commonly interfering species from backstreaming
into the ionization volume. This produces peaks free of spectral
overlap.
A Choice of Detectors
The CIS series analyzers come standard with both a Faraday cup
detector (10 ppm detection) and a continuous dynode electron multiplier
(1 ppm detection). The software allows you to easily switch between
detectors.
Versatility
The CIS systems can also be used in a so-called "RGA mode".
In this mode, the unit has a lower minimum detectable partial pressure,
but a lower maximum operating pressure as well. The RGA mode is
used, for example, in the first stage of a sputtering process when
the chamber is evacuated to a low pressure, and the quality of the
vacuum is checked for leaks and harmful contaminants. The unit can
then be switched to a CIS mode for sampling directly at higher pressure.
Complete Programmability
A standard RS-232 interface is provided along with a complete programming
reference. All probe parameters can be controlled and monitored,
and data can be acquired for use in custom applications.
Windows Software
The CIS systems are supported with a real-time Windows
software package that runs on PCs. The intuitive graphical user
interface allows measurements to be made quickly and easily. The
program is fully interactive, giving the user complete control of
the graphical display. Screens can be split for dual-mode operation,
scales can be set to linear or log format, and data can be scaled
manually or automatically. Data is captured and displayed in real-time
or scheduled for acquisition at a given interval for long-term data
logging. Features include user-selectable units (ppm, Torr, mbar,
Pa and A), programmable audio and visual alarms, and comprehensive,
on-line help. The software allows complete CIS head control with
easy mass scale tuning, sensitivity calibration, ionizer setup,
and electron multiplier gain adjustment. For further analysis, data
files can be saved in ASCII format for easy transfer into spreadsheets.
Graphic images can be saved as META files or copied to the clipboard
for importing into other Windows programs. The software
also provides password protection for locking out head parameters
so that casual users can’t alter important settings.
An optional stand-alone monitor (PPM100)
can be used to control the RGA without a host computer.
Multi-Head Operation
The software supports multiple head operation when more than one
CIS is needed. Up to eight ECUs can be monitored from the software.
Pumping Requirements
The CIS instruments require connection to a pumping system with
an effective pumping speed of at least 40 L/s and a base pressure
of less than 10-9 Torr. The connection
port is a 2.75" Conflat®
flange. Option O100TDP provides a turbo pump which mounts directly
to the CIS head along with a diaphragm roughing pump. When this
option is ordered the entire analyzer is assembled, tested, and
calibrated at the factory. Users can provide their own pumping station;
however, it is the user’s responsibility to ensure that the
pumping system does not damage or limit the performance of the instrument.
Affordable Performance
The SRS CIS systems offer state-of-the-art performance for a fraction
of the cost of competing models. Standard systems include faraday
cup detector, electron multiplier detector and Windows
software. Options include built-in power module for AC line operation,
and a pumping package that includes a turbomolecular pump and diaphragm
pump.
CIS Dimensional Drawwing
| CIS Parameter |
Range |
CIS mode |
RGA mode |
| Electron emission current (mA) |
0 to 1 |
0.05 |
0.5 |
| Electron energy (eV) |
25 to 105 |
70 or 35 |
70 |
| Ion energy (eV) |
4 or 8 |
4 or 8 |
4 or 8 |
| Extraction voltage (V) |
0 to -150 |
-50 (typ.) |
-50 (typ.) |
Sensitivity (A/Torr)
(for N2 @ 28 amu) |
|
10-6 |
10-5 |
| Linear range upper limit (Torr) |
|
2 × 10-3 |
10-4 |
| MDPP (Torr) |
|
10-8 |
10-9 |
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Notes
1. The CIS tests were performed with a 70 L/s hybrid turbomolecular
pump, backed by a diaphragm pump, attached to the side port
of the CIS Cover Tee.
2. The RGA mode sensitivities reported were calculated for
N2 at less than 10-5
Torr.
3. The CIS mode sensitivities were calculated for N2
at 1 to 5 × 10-4
Torr.
4. MDPP (minimum detectable partial pressure) is determined
by measuring baseline levels for Faraday cup detection in
the presence of 28N2
at 10-5 (RGA mode) and 10-3
Torr (CIS mode). Up to 3 orders of magnitude improvement in
detectability is possible when the electron multiplier is
turned on.
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Electron Multiplier
Analog Mode
Pressure vs. Time
Library Mode
