Apologies in advance for not looking harder for a 'search' function to see if this question's been asked before (is there one?), but I'm struggling with my first Eagle Light (6.4.0) board design, and one of my bigger stumbling blocks fo far has to do with an SMD QFN part I'm trying to use. The part has a large, grounded-to-substrate square pad in the center of its package that I gather needs to be soldered and routed to circuit ground. I can add the requisite square SMD pad to the "package"s layout, no problem, but how should I arrange for some vias inside the pad area to connect up to pads on the other side of the board? The obvious thought was just to plop some through-hole pads inside the borders of the SMD pad; that's the sort of thing that one could do with the previous (provided for free from the PCB fab house I've been using) package. And (so far, although from the way Eagle's been feeling so far, I imagine you don't get to find out whether the library components you must create before beginning a board layout have problems until you finish the layout). When I do that, though, the top solder-paste silkscreen still comes out saying to smear paste over the entire center square area. Is it possible to prevent the solder paste from dribbling down into the via holes I want to have inside the square area? For that matter, covering the whold 5x5mm area with paste is a little overkill. Isn't there a way to draw "negative" overlaid shapes like circles or polygons, and have them chop holes in other already-drawn shapes?
