Rev 37 Operator’s Manual OM-610-1002-1
page 38 SECTION 6 MAINTENANCE PDS-2010
6.1.3 Cold Trap Probe (Thimble)
To achieve the coldest possible cold trap probe surfaces and to preclude the separation of trapped deposits,
remove and clean the cold trap probe promptly
* after each run. Set the probe in the holder provided on the
machine. Corrosive compounds are produced (in small amounts) as a byproduct of Parylene deposition and
are subsequently condensed on the probe surface. Therefore, regular cleaning is imperative to prevent
corrosion and pitting of the cold trap probe. See the MACHINE SAFETY Section for precautions required
when handling cryogenic apparatus. See End-of-Run in Section 5 for handling of mechanical chiller probe.
*There are two opposing needs to consider when moving the cold trap probe:
• The flex line and its junction to the probe need time to warm a little so they are not damaged by
flexing.
• The probe needs to be removed promptly so the frozen material on the probe does not drip or fall
into the cold trap.
Try to allow enough time for the flex line and junction to warm before moving, but do not wait so long
that the frozen material on the probe begins to melt. Use special care to minimize stress on the line and
junction when moving the probe to the holder.
To remove the thin layers of polymer that deposit on the lower portion of the probe, spray liberally with
Microsoap solution and use a non-metallic abrasive pads such as Scotch Brite.
6.1.4 Vacuum Integrity
Vacuum leaks are usually due to contamination of sealing surfaces and O-rings. The contamination, in most
cases, has been found to be small particles of trapped polymer. It is good operating practice to check the
sealing surfaces of the vaporizer access door, chamber ring, and cold trap probe flange before pumping the
system down. For leak detection, the use of solvents is NOT recommended. Solvent flammability and noxious
vapor creation could result in serious injury or equipment damage. Use of a helium leak detection system is
the approved method.
6.1.5 Vacuum Pump
For optimum performance, the pump’s oil should be kept free from foreign particles and excessive
condensable vapors. Parylene vapors in particular can have a significant negative effect. The oil in the vacuum
pump provides lubrication and wear-protection for the pump internal components and also performs a critical
role in the pump's ability to reach its ultimate pressure. The 2010 includes both a cold trap and a wire mesh
inlet screen to protect the pump from most contaminants. However, as with any oil-lubricated device, the
pump will require routine oil changes. Refer to the documentation supplied by the manufacturer for a
complete description of operation and service to the vacuum pump.
Schedule oil changes for the 2010 vacuum pump based upon the following events, whichever comes first:
• After 10 coating runs.
• After a process throughput of 120 grams of Parylene dimer.
• Anytime that the cold trap has exceeded (been higher than) -75°C during deposition
• Whenever the oil appears cloudy, dirty, or otherwise contaminated.
• When, after a coating cycle has been performed, the machine is scheduled to be idle for more than one
week. (Change the oil before periods of non-use to prevent corrosion of pump components during
storage.)
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