There are usually very simple ways to diagnose a vacuum leak. Here is a short list of things to help rectify the problem.

  1. Troubleshooting: What was the last thing you did before you suspected there was a leak? Backtracking will often lead you to the cause of the leak.
  2. Is it a real leak or a virtual leak? A deposition tool in need of a thorough cleaning can trap enough air/nitrogen behind accumulated deposits on chamber walls, deposition sources, or shielding to give the appearance of a real leak. Cleaning things up usually solves the problem.
  3. Is the magnitude of the pressure rise affected by other events? A base pressure that increases in size as process temperature increases may not be a leak per se but rather an outgassing that results from contamination. A residual gas analysis is probably needed to determine the cause. On the other hand, a pressure increase that is related to the rotational position of a rotary feedthrough is more likely to be a real leak.
  4. Once you’ve deduced that it’s a real leak, a helium leak detector will be needed to determine its precise location. Most vacuum systems are equipped with a leak test port. Unless that portion of the vacuum system has an isolation valve at the leak test port, venting the system before connecting the helium leak detector will be necessary.

We can help make your leak testing less troublesome with our leak test hardware kits. These consist of a manual vacuum valve, adaptive vacuum fittings, and stainless flex hoses. Having a manual isolation valve permanently located on the vacuum system means that you’ll probably not have the vent in the system prior to leak testing. Call us at (510) 583-5624 for more information.

IKE (paw print)