US Patent 8704368 Stackable via package and method

A stackable via package includes a substrate having an upper surface and a trace on the upper surface, the trace including a terminal. A solder ball is on the terminal. The solder ball has a solder ball diameter A and a solder ball height D. A via aperture is formed in a package body enclosing the solder ball to expose the solder ball. The via aperture includes a via bottom having a via bottom diameter B and a via bottom height C from the upper surface of the substrate, where A<B and 0=<C<½×D. The shape of the via aperture prevents solder deformation of the solder column formed from the solder ball as well as prevents solder bridging between adjacent solder columns.