Patent ID: 9293338
Filing Date: 2016-03-22
CPC Classification: H01L

Claim Text:
1. A semiconductor packaging method, comprising: providing a semiconductor substrate, the semiconductor substrate having a first surface and a second surface; forming solder pads on the first surface of the semiconductor substrate; forming an insulating layer on the first surface of the semiconductor substrate and exposing the solder pads; forming an electroplating seed layer on the exposed solder pads and on the insulating layer on the first surface of the semiconductor substrate; forming a plurality of columnar electrodes over the electroplating seed layer, the columnar electrodes including first columnar electrodes over first portions of the electroplating seed layer on the exposed solder pads, and second columnar electrodes over second portions of the electroplating seed layer on the insulating layer; forming a diffusion barrier layer in a “U” shape with curled up edges to cover a top surface and sidewall of each columnar electrodes and to cover a top surface of the each portion of the electroplating seed layer surrounding the columnar electrode; forming a wetting layer over the diffusion barrier layer on the first columnar electrodes and the second columnar electrodes, such that the wetting layer has a cross-section in a “U” shape with curled up edges; after forming the barrier layer, removing portions of the electroplating seed layer between adjacent columnar electrodes to simultaneously form first columnar electrodes together with the “U” shaped wetting layer and the diffusion barrier layer thereon to electrically connect to the semiconductor substrate via a solder pad and the electroplating seed layer, and simultaneously form second columnar electrodes together with the “U” shaped wetting layer and the diffusion barrier layer thereon to be electrically isolated from the semiconductor substrate by the insulating layer; forming a first solder ball over the diffusion barrier layer on each first columnar electrode; providing a packaging substrate having solder terminals corresponding to the solder balls; and mounting the semiconductor substrate onto the packaging substrate in a flipped position, such that the first solder balls are connected with the solder terminals.