Operation - HELIX CTI-CRYOGENICS CRYO-TORR 100 Installation, Operation And Servicing Instructions

CTI-CRY<X.ENICS
HELIX TECHNOLOGY CORPORATION
Section 5:
Operation
5.1
5.2
5.3
5.4
5.5
5.6
5.7
5.8
Before Startup. . . . . . . . . . . . . . . . . . . . . . . 5·1
Rough Pumping (Preliminary Vacuum Pumping) . . . . 5·1
Rate of Rise (ROR) . . . . . . . . . . . . . . . . . . . . . 5·1
Startup and Cooldown . . . . . . 5·2
Normal Operation. . . . . . . .
Cryopump Oxygen Procedures
Determining Crossover Pressure. . .
Determining Cryopump Capacity for
Condensable Gases . . . . . . . . . .
. .
.
.
. . . . .
. .
. . .
.5·3
.5·3
5·4
5·4
5.9 Determining the Number of Crossover Cycles. 5·5
5.10 Cryopump Shutdown Procedures. 5-5
5.11 Cryopump Storage. . . . . . . . . 5·5
5.12 Hazardous Materials
. . . .
.
5.1 Before Startup
Before beginning system operation make certain all the
steps in the inspection and installation procedures have
been completed and confirmed.
Operating Log
It is advisable
to
create and maintain an operating log.
The record will assist in troubleshooting should
problems arise. The log should include as a minimum
the following data: the cooldown time
to
20K; the
roughing time to 5011; the time
to
base pressure at
crossover; the time between regeneration; and, the
compressor pressure reading. These recorded values are
useful for future performance reference.
5.2 Rough Pumping (Preliminary
Vacuum Pumping)
It
is not necessary to rough pump the cryopump
to
very
low pressures. Experience has shown that a roughing
5-1
. . . . . . . . . . . . . . 5·5
pressure between 50 and 75 microns is all that is
required. This pressure can be measured with a DV-6M
thermocouple
(TC)
gauge mounted as close as possible
to the roughing port.
5.3 Rate of Rise (ROR)
Rate of pressure rise in a newly installed cryopump is an
important measure of the tightness of your installation.
This is obtained by closing the roughing valve (see
Figure 3.2, page 3-3) when the pressure has reached
50-75 microns. Observe the rate of pressure rise over
the five-minute period. A rise of less than 10 microns/
minute over a five-minute period (50-microns total) is an
indication of the integrity and cleanliness of the cryo-
pump. If the total ROR
is
greater than 50 microns,
repurge the cryopump, check for evidence of leaks, and
repeat the roughing cycle and ROR.
Note: Such a procedure may be adapted
to
quickly
check the integrity/cleanliness of your process
chamber.