I have the distinct (dis)pleasure of making some PCBs with QFN/MLF packages that have exposed copper paddles. I think I'll need to use stencils to properly apply paste for these packages. It appears that PCB simply uses SMT pads (slightly shrunk) as the apertures for the paste layer. I think this is a simple effective design for most packages --- except exposed ground paddles. These require that the paste be broken into smaller "blocks" with say 75% coverage of the paddle. (See Analog AN-772)
Has anyone on the list dealt with this issue in the past? If not, I wonder if there is any way to distinguish paddle pads from regular ones so that I could modify the paste layer code to do the right thing. I guess we could do something like look for square pads with a size > Xmm on a side. That seems a big fragile though. Hmmm, -DC _______________________________________________ geda-dev mailing list [email protected] http://www.seul.org/cgi-bin/mailman/listinfo/geda-dev
