Definition
Via-in-pad refers to via that is plated through and filled with a conductive (or non-conductive) epoxy plugging ink that is then planarized and plated over. Usually, this via will be patterned into a BGA pad for direct soldering. IPC-4671 contains various definitions of plugged vias.

Applications
Via-in-Pad saves PCB real estate by providing conduit for heat transfer. Many of today’s fine pitch BGA and flip-chip component footprints do not allow for running traces and vias (typical “dog-bone” BGA configuration). Instead, the BGA pad, trace, and via are combined into one single feature allowing for 50% space savings. Conductive inks transfer heat away from critical components.

Common Issues
Voids / dimples, surface planarity and more.
Click here to read more

Sample Boards

Blind Via / Via in Pad / Fine Pitch BGA
Click on picture to proceed

Mouse over pictures below to see description