G 04128 - Edition 02 - July 12
3/4
C 00
Safety recommendations
for harsh processes
Safety information related to SIH
4
/H
2
processes
(cont’.)
GENERAL RECOMMENDATIONS
It is necessary to pay particular attention to:
Leak tightness of the whole system:
Be sure there is no air leak on pumping system itself and on vacuum line. Leak rate has to be lower
than 1 · 10
-6
hPa l/s of Helium. Air ingress to inner side may lead to uncontrolled reaction between SiH
4
and O
2
. If the leak is big enough, H
2
/O
2
mix could be ignited by decomposition of SiH
4
. In the worst
case, explosion can occur.
End user must guarante vacuum line and exhaust line leak-tightness.
Be sure there is no leak at pump exhaust. An overpressure Helium leak test has to be performed.
Maximum leak rate is 5 · 10
-5
hPa l/s from pump exhaust to Abatment system inlet.
N
2
purge:
Be sure pump is purged with N
2
.
Air is prohibited
.
This purge needs to be maintained at any time to avoid air back streaming likely to enter in contact
with flammable deposits.
This purge could be exceptionally stopped when process gases are off and full system has been flushed
with nitrogen. This has to be secured in a safe and robust procedure.
Be sure N
2
purge warning and alarm are enabled and properly interlocked with the process equipment.
Be sure N
2
purge is prolonged at least 10 min after pump stop in order to evacuate residual process
gases after pump stop.
Process line (from process chamber to abatement inlet) opening before the end of previously described
purge must be strictly prohibited.
Communication with tool:
Global warning and alarm and specific N
2
warning and alarm has to be sent to the tool which must
shut off active gases.
Immediate corrective actions must be scheduled in case of N
2
warning or alarm signals
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adixen Vacuum Products – A3H Series Operating instructions
