Hi Karenanne,

We have a product with a 144 pin, .8mm uBGA that I routed
using 19 mil Cu pads and 15 mil solder mask openings, and
4 mil lines and spaces in the area under the IC.  This part had
an opening in the center so some vias could be placed there
with the remainder around the outer edges.  The board was
very dense SMT with parts top and bottom so via sites were
at a premium.  I did manage to get the part pin escaped and
routed using our standard 24mil via pad with a 12 mil drill, but
it did take a lot of effort and I reduced the via pads on the outer
layers to 22 mils.  I could send you a plot of the routing  if you'd
like, just tell me what format, ie. tif, pdf...   Good Luck!

Mark F. Walter - Staff Printed Circuit Board Designer
Motorola Paging Products Group West
5401 N. Beach St., Fort Worth, TX. 76137-2794

Telephone: (817) 245-2366  FAX: (817) 245-4850
Email: [log in to unmask]
Pager: 1-800-SKYTEL2(759-8352) PIN# 2452366


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