Patent ID: 6720244
Filing Date: 2004-04-13
Classification: H01L

Abstract:
A bump fabrication method comprising:providing a wafer having an active surface and a plurality of bonding pads formed on the active surface; forming an under bump metallurgy (UBM) layer onto the bonding pads, wherein the under bump metallurgy layer includes at least a wetting layer having an oxidized region thereon and positioned at a top of the under bump metallurgy layer; patterning a masking layer on the active surface wherein the masking layer has a plurality of openings to expose the wetting layer with an oxidized region thereon; removing the oxidized region of the wetting layer using a plasma ashing method; forming a flux film over the active layer, wherein at least a portion of the flux film covers the wetting layer; filling a solder paste into the openings; performing a re-flow process to form a plurality of bumps after the solder paste meltsso that the flux film removes the oxidized region of the wetting layer; and removing the masking layer.