Patent ID: 8796848
Filing Date: 2014-08-05
Classification: H01L,H05K

Abstract:
1. A circuit board, comprising: a substrate comprising a top surface and a base surface opposite to each other; at least a top pad disposed on the top surface and at least a base pad disposed on the base surface; a top solder resist layer disposed on the top surface and covering a portion of the top pad and a base solder resist layer disposed on the base surface and covering a portion of the base pad, wherein the top solder resist layer has a first opening exposing a portion of the top pad, and the base solder resist layer has a second opening exposing a portion of the base pad; and a pre-bump disposed on the top pad and located in the first opening, wherein a conductive layer is formed on the base surface, covering the base solder resist layer and the base pad and electrically connected to the base pad, a plating resist layer is formed on the conductive layer and has a third opening exposing a portion of the conductive layer, wherein after the pre-bump is electroplated on the top pad by applying a current to the conductive layer through the third opening, the plating resist layer and the conductive layer are removed sequentially; and wherein the pre-bump has a protrusion protruding from the top solder resist layer, and a maximum width of the protrusion is less than or equal to a width of the top pad.