I recently made a board for the TPA3004D2 Class-D Amplifier Chip. It has a fairly large thermal pad on the bottom for heat dissipation. I used an existing TQFP-48 library in Eagle that had a thermal pad which I resized (my first mistake). I then put a 4x4 grid of vias connecting the thermal pad to the bottom ground plane, as recommended in the datasheet. Anyways, I got the boards yesterday and this is what they look like:
As you can see from the picture, the 4 vias in the center of the top-layer grid got grouped together which is good. But for some reason, the thermal pad that was supposed to be there never got fully "etched" out, and the copper is actually under the purple, thus reducing the surface area that the thermal pad will contact the vias with. So what are my options for soldering this? I was thinking about going in from the bottom and soldering through each via, thus giving me maximum area and heat transfer. Thoughts?