Gaby -
At a previous employer, we had a case where we designed the board to have
the mask between the pads (HASL).  The vendor had difficulty achieving a
quality finish -the mask simply disappeared between leads upon curing.
 This vendor claimed we were overly cautious in designing the boards with
the mask between the pads and that we were his only customer who was
doing so for the 16 mil pitch.  My comments are if you don't need masking
between fine pitch pads [to prevent bridging], where else would you need
it?  That said, we used the boards without the mask between pads and did
not have a bridging problem for paste, place, and reflow.  Any manual
rework of these parts, however, was obviously very difficult!

Lainie Loveless
Quad Systems

 ----------
From:  TechNet
Sent:  Wednesday, June 24, 1998 11:16 AM
To:  [log in to unmask]
Subject:        [TN] Solder mask between fine pitc


Hi, TechNetters!
Could you please share with me your experience about pro and con's
regarding solder mask
between fine pitch-16mil- pads in relation to the finish of the PCB pads
?
Not being greedy, I'll save the next question for after some answers.
Thank you,
Gaby

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