K465i Operations and Maintenance
P/N 1212831 Rev C
Page 5-166
Copyright
©
2012
Veeco Instruments, Inc. Confidential
All Rights Reserved
2. If the leak detector reading is within the accepted passing range, proceed to the next fixture and leak
check it accordingly.
3. If the leak detector sense helium at an unacceptable level, follow the steps below:
a. If the leak is suspected of being external, tighten the VCR first and then re-check the fitting for
leaks. If the VCR now passes the leak check, proceed to the next fixture and leak check it
accordingly.
Caution:
Before opening the VCR, return that portion of the system to
atmospheric pressure by backfilling with nitrogen. If the VCR leads to the reactor, backfill
the reactor with nitrogen. After replacing the VCR gasket, restore the system to vacuum and
proceed with the leak checking.
b. If a leak is still detected after tightening the VCR, remove the VCR gasket from
the connection and replace with a new one.
c. If a leak is still detected after performing steps a and b then replace the VCR
fitting with a new one. Note that this will require welding, and either a qualified
welder should perform the work, or call
Veeco Compound Semiconductor
at 1-
8TURBODISC.
VALVES
In general, all valves - pneumatic, needle and manual are leak checked in the same
manner; however, mitigating a leak depends on which type of valve has the leak.
Note:
This check is for an external leak, not an internal leak.
All pneumatic and manual valves should be closed, while needle valves should be open, and
the valves supplying them closed.
Procedure 5-29: Valve Leak Checking
All Valves
1. Open the valve that is being leak tested.
2. Spray helium around the valve (on both sides, and on top and bottom). If the leak detector reading is
within the accepted passing range, then leave the valve open. Proceed to the next fixture
upstream
of
the valve just tested and leak check it accordingly.
3. If the leak detector senses helium at an unacceptable level then attempt to eliminate the leak by doing
the following:
4. Tighten all of the VCRs (if not welded) on the valve and then re-check the valve for a leak. If the valve
now passes the leak check, proceed to the next fixture and leak check it accordingly.
5. If a leak is still present after tightening the VCRs, replace the metal gasket on the VCRs and recheck.