gEDA-user: "soldermask via caps"

[andrew whyte <ajwhyte@xxxxxxxxx>]

  I've been working on a number of QFN packages recently (for example
the ATMEGA664).  The package has a large central ground pad, and 44
small pads around the outside.

  There is a known problem in layouts with vias inside pads, where
solder wicks down into vias and causes the joint to be poorly
soldered.  I found this link  about how to avoid this problem:

http://blog.screamingcircuits.com/2007/04/soldermask_via_.html

  Although  I could change the footprint to have holes in the central
pad, then put the vias into them,  this requires that I know the drill
technology at the time as I specify the footprint.  Is there a way to
edit the solder mask after parts have been placed onto the pcb?  Or a
better way to do this entirely?



-- 
âââââââââââââââââââââââââââââââââââââââââââââââ
     Andrew Whyte
     paramita ltd
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