[labnetwork] cryopump maintenance

[Wang,Xiaojin]

Dear colleagues:

We have a cryo-torr 8F pump on our sputtering system PVD75 manufactured by Kurt J.Lesker. It has experienced a very strange incidence lately. During the weekend, the gate valve between process chamber and cropump shut off itself and the pressure in the chamber went up to several torrs while the gate valve is supposed to open and let cropump pump the system to 10^-7 torr. The temperature of cropump went up to 215K and it was still pumping. After we regenerated the cryopump the cooling time for it to be below 20K has been doubled and the lowest temperature it can reach is 18K while it used to be 13K.

Did anyone run into this kind of incidence before and what could possibly cause it?

What do we need to do to prevent it from happening again?

Is there anyway to bring the good performance back to the pump again?

We also have a cryopump on e-beam system. Generally, what kind of maintenance need to be done on these cryopumps so that we can maximize their lifetime?

Your valuable suggestions are very appreciated.

Best wishes
Xiaojin Wang

Senior process engineer
Micro/nano technology center
University of Louisville
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://mtl.mit.edu/pipermail/labnetwork/attachments/20131219/a72a8d81/attachment.html>