Abstract: A method for forming metal bumps is disclosed, comprising: providing a substrate including a plurality of pads; forming a solder mask on the substrate, wherein the solder mask has first openings to expose the pads; forming a photoresist layer on the solder mask, wherein the photoresist layer has second openings to expose the pads; forming a conductive layer on the phototresist layer, wherein a sidewall of each second opening, a sidewall of each first opening and the pads are covered with the conductive layer; forming a metal layer on the conductive layer by electroplating to fill the first and second openings; performing a planarization step to remove the conductive layer and the metal layer on the photoresist layer so as to remain the conductive layer and the metal layer in the first and second openings; removing the photoresist layer and performing a reflow step to form metal bumps.

Abstract: A method for forming metal bumps is disclosed. Steps of the method include supplying a substrate containing a plurality of pads; forming a first photoresist layer on the substrate, herein the first photoresist layer covers the pads; performing a planarization step to remove a portion of the first photoresist layer so as to expose the pads; forming a conductive layer on the first photoresist layer and the pads; electroplating a metal layer on the conductive layer; forming a patterned second photoresist layer on the metal layer; a portion of the metal layer and the conductive layer which are not covered by the patterned second photoresist layer is removed by using the patterned second photoresist layer as a mask; removing the patterned second photoresist layer; and forming a solder mask on the substrate, wherein the solder mask has a plurality of openings to expose the metal layer located on the pads.