Methods of fabricating a via-in-pad with off-center geometry

摘要

The electrical contacts, such as ball grid array (BGA) solder balls, of an integrated circuit (IC) are coupled to printed circuit board (PCB) bonding pads that include vias. According to an embodiment of an electronic assembly, the vias are formed off-center, so as to inhibit bridging between adjacent solder balls during a solder reflow operation by minimizing the effect of solder ball ballooning resulting from outgassing of a thermally expansive substance, such as a volatile organic compound (VOC) from the via channels. The bonding pads are separated into two groups, each having vias offset in a different direction, so that asymmetric surface tension forces in the molten solder during a solder reflow operation do not cause the IC to slide to one side. A substrate, an electronic assembly, an electronic system, and fabrication methods are also described.