Packaging substrate having electrical connection structure and method for fabricating the same
A packaging substrate having an electrical connection structure and a method for fabricating the same are provided. The packaging substrate have a substrate body with a plurality of conductive pads on a surface thereof; a solder mask layer disposed on the substrate body with a plurality of openings corresponding to the conductive pads, the size of each of the openings being larger than each of the conductive pads; and electroplated solder bumps for covering the conductive pads to provide better bond strength and reliability.
1. A packaging substrate having electrical connection structures, comprising:
a substrate body having a plurality of conductive pads on a surface thereof;
a solder mask layer disposed on the surface of the substrate body and formed with a plurality of openings corresponding in position to the conductive pads, each of the openings being larger in size than each of the conductive pads;
copper bumps disposed on the conductive pads for fully covering the conductive pads exposed from the openings, and the copper bumps protrude above the solder mask layer, each of the openings is larger in size than each of the copper bumps;
electroplated solder bumps mounted on the copper bumps for fully covering the copper humps exposed from the openings, wherein the electroplated solder bumps fill the openings: and
a conductive seed-layer formed between the conductive pads and the copper bumps.
2. The packaging substrate of claim 1 , wherein the electroplated solder bumps are made of a material selected from the group consisting of Sn, Ag, Bi, Zn, In and alloy of a combination thereof.
3. The packaging substrate of claim 1 , wherein the electroplated solder bumps protrude above the solder mask layer.