[labnetwork] Pore size for scrubber

[Kunigunde Cherenack]

Hello everyone

I have a question regarding the scrubber filter in our PECVD-system: 
specifically, we are trying to find out what grade of filter we should 
purchase for our re-circulating scrubber. Our current system set-up is 
as follows: the gases in the processing chambers are pumped out and 
passed through a cracking oven and exhausted into a re-circulating 
scrubber. We're currently using a filter with 150 micron diameter pores 
in the scrubber, mainly to filter out SiO2 particles that end up in the 
water. However, it seems as if the filter is not really doing it's job 
and most of the residual particles end up in the water and are not 
caught by the filter. For this reason we were considering replacing the 
current filter with a filter that has smaller pores. The supplier can 
make filters with pores all the way down to 1 micron in 
diameter......however, we're concerned that using a filter with such a 
fine grading would put too much strain on the pump in the scrubber. Do 
any of you have an opinion/recommendation on how fine the pores of a 
scrubber filter should be? I'd welcome any advice you could give 
me....thanks in advance!

sincerely

Kuni Cherenack
kcherena at princeton.edu
graduate student, Prof Wagner's group,  Princeton U.