Patent ID: 9704735
Date: 2017-07-11
CPC Classifications: H01L

Claim:
1. A package substrate, comprising: a build-up structure comprising at least one insulating layer, at least one via, and at least one conductive layer; a first plurality of contact pads in a first side of the build-up structure, the first plurality of contact pads each having an external surface co-planar with the first side of the build-up structure; a second plurality of contact pads on a second side of the build-up structure opposite of the first side; a first solder resist layer on the first side of the build-up structure; and a second solder resist layer on the second side of the build-up structure, the first and second solder resist layers covering the first and second sides of the build-up structure, respectively, wherein the first solder resist layer is disposed on sidewalls of the first plurality of contact pads and is not formed on the external surfaces of the first plurality of contact pads, and the second solder resist layer is formed on a portion of the second plurality of contact pads on the second side of the build-up structure.