>    I would be concerned about my internal layer connection.  All the
> Z-axis thermal stresses are now borne by the innerlayer connections.
> 
	Ed,

	Here are a couple of design approaches to help improve the
	spacings, which may or may not be the root cause but sound
	like they would help the manifestation of the problem:

	1. Reduce pad size rather than eliminate it.  I suspect that
	you would still get the improved z-axis stability of the top
	side pad even if it were a tangency situation.  This would
	presumably improve your spacing.

	2. Use soldermask defined pads.  Leaving the pad size the
	same, reducing the soldermask opening "some" would also serve
	to increase your spacing.  My understanding is that while this
	approach is being discouraged in BGA attach, it may be useful
	in this through-hole application.

	Maybe we can get some assembly or reliability comments on 
	these angles.

	Good luck,
-- 
 
      Jeff Seeger                             Applied CAD Knowledge Inc
      Chief Technical Officer                      Tyngsboro, MA  01879
      [log in to unmask]                               508 649 9800

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