[labnetwork] question on Particle Monitoring

[Morrison, Richard H., Jr.]

Hi All,

The new Cleanroom at Draper has been operational since November. We are trying to satisfy the ISO standard for particle monitoring. In my mind it is more important to choose monitoring points by areas where wafers are exposed to the cleanroom atmosphere. So load stations, microscopes ect. If you follow the ISO requirements it breaks the space into square meter sections and you measure in that section, regardless of what goes on in that area. I was wondering what members of this group did for particle monitoring locations.

The other factor is, how many samples you take to be 95% confident in the room specification. The total air volume at one location must be enough that you have 95% confidence of capturing an out of specification reading, this equates to  2.8 liters.  It seems to me that a Class 10 room needs many more samples at a location than a class 1000 room, any thoughts?


Thanks
Rick


Draper Laboratory
Group Leader Microfabrication Operations
555 Technology Square
Cambridge Ma, 02139-3563

www.draper.com
rmorrison at draper.com
W 617-258-3420
C 508-930-3461

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