| 摘要 |
A method and circuit structure for mounting a leadless IC package to a substrate having a thermal pad on a first surface thereof, a plurality of contact pads surrounding the thermal pad, and one or more plated vias in the thermal pad. The leadless package is attached to the substrate with solder that thermally connects the package to the thermal pad. To prevent solder flow into the plated vias during reflow, a solder mask is provided on the first surface of the substrate, at least a portion of which is deposited on the thermal pad and surrounds the plated vias but does not block the plated vias. The solder mask portion defines a barrier between the solder and the plated vias, but allows for outgassing through the vias during solder reflow.
|
