Hi,

  Thanks for your reply.
  In my case we have pad to pad gap of 34mils and the track inbetween will have a width of 6mils. Add to it 3 mils offset requirement for solder mask we will still be left with alomost 11 mils gap between the pad edge and track on each side.

      But can there be any issue in terms of placement and stability of connector? Or any probability of track shorting to connector body ? or any other issue which you can see can happen in production?

  If we need to go ahead with this then what things do we need to specify to the PCB fabrication house to ensure protection on this issue?

  Its first time we are trying to have track between the SMT pads of the connector.  But whats the DFM guideline in terms of recommended distance between track edge and pad edge?

  I am attaching the connector details and footprints details for your review. Apologise that I have put in too many questions but really look forward to your comments and suggestion on those.

  Rgds
  Prashant

Wayne Thayer <[log in to unmask]> wrote:
  Prashant-

Main problem is simply solder masking the track between the pads. Most
board fab houses will want 3mils of "backoff" for generating the solder
mask artwork. This allows a 3mil targeting error between the mask and
the metal. With 3mils on each side, that means the maximum gap can be
6mils from a pad to an adjacent trace (3mils target error plus 3 mils
backoff) . So as long as its greater than 6mils from each pad to the
edge of the trace, any reputable place can build the board and assure
that the track will be fully masked.

You can get higher resolution, but you will have to pay significantly
more for it.

Wayne Thayer

>>> [log in to unmask] 11/21/2006 12:56:11 am >>>
Hi,

I need your expert opinion on this. The design team here wants to put
a 6mil track in between the pads of the connector on the component side.
Its an 80 pin dual connector and they need to take out these 6 mils
track in between every two pads of the connector.(ie in all 20 tracks on
each side of the connector).

Is this an issue of DFM violation? Will it have an impact on the
stability,placement and soldering of the connector thru reflow? Any
process or reliability issues which we can foresee?

I am attaching the data sheet of the connector. It is also having two
boss pins for placement guiding.

Thanks in advance for expert opinions from all of you.

Regards
Prashant Chopra
Manufacturing Process & Projects Engineer


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