We are in the early stages of developing a specification for  an
improved level of cleanliness in the  Imaging area (Yellow room) of our
captive board shop. We  operate one 9 or 10 hour shift, and the area in
question is about 2,000 sq. ft., with  about 6 people in it.  We image
cores and outer layers here, and apply LPI, at different stages in the
process. The room has its own air handling system.

We have some controls in place - restricted access, tacky mats,  hair
cover and smock requirements, cleaning schedules, restrictions on some
kinds of paper. We used to have the area positively pressurized
(presently at .02" H2O), and we used to have HEPA filters, which seem to
be gone now.

Lines and spaces go down to .008"/.008", and we do about 75,000 boards
per year.

How are some of you other "fabbers" specifying conditions for your
imaging areas.  Is, for example, a class 100,000 clean room an
appropriate specification?  Is anbody doing class 10,000 for 8 mil
lines?

Second question- what is an effective pressure difference between the
clean area and the outside environment.  It seems like too low is
ineffective (read $), too high requires too much make-up air (read $
again).

Any input is appreciated.

Mike Matson
Manufacturing Engineer
Woodward Governor Company
Fort Collins, CO
Ph: (970) 498-3285     FAX: (970)498-3065
email: [log in to unmask]

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