We are a fab shop and produce dams down to 3mil with a
minimum of 2.5 annular clearance around pads.  Some of our larger
customers however spec no dams between 20mil pitch devices and
smaller as they have found that in a well tuned assembly
environment dams this small create more defects than they
prevent.  Maybe someone more familiar with the assembly process
can provide more specifics on this.

Regards
John Parsons
Circuit Graphics Ltd.

> > Hi all,
> >
> > Just a quick industry capability questions. Are board manufactures still
> > having trouble holding mask dams between fine pitch (19mil) SMT pads. As
> > recent as a year or so ago I was under the impression that board shops
> > would ask the remove these small dams when they got them on the Gerber
> > data. Is this still common. I am interested in what most people think is
> > feasible regarding mask dams that are 4 mils wide and smaller. All
> > responses are appreciated.
> >
> > Ed Cosper
> > ABC
> >
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