Via in pad, means the via holes designed on the SMD PAD, specially designed on the BAG (Ball Grind Array) area which comes with extremely narrow trace width and space.
After resin filling hole, copper is plated over the hole as a metal cap/pad to guarantee the hole’s conduction action and smoothness, which is called Plating Over Filled Via. In short, we can understand via in pad as the hole below the pad.
Via in pad caters to the necessary of HDI. Owing to its conduction action, it can simplify routes and save horizontal space of printed circuit board, and improve board’s density and interactivity.
Filled with Resin and Plated over to be Via in Pad
