Surface finishes with low rbtv for fine and mixed bump pitch architectures

Abstract

Embodiments described herein include electronic packages and methods of forming such packages. An electronic package includes a package substrate, first conductive pads formed over the package substrate, where the first conductive pads have a first surface area, and second conductive pads over the package substrate, where the second conductive pads have a second surface area greater than the first surface area. The electronic package also includes a solder resist layer over the first and second conductive pads, and a plurality of solder resist openings that expose one of the first or second conductive pads. The solder resist openings of the electronic package may include conductive material that is substantially coplanar with a top surface of the solder resist layer. The electronic package further includes solder bumps over the conductive material in the solder resist openings, where the solder bumps have a low bump thickness variation (BTV).