Process of fabricating bumps

A process for fabricating bumps on a wafer, the wafer having an active surface, the wafer being provided with a passivation layer and a plurality of conductive pads, both the passivation layer and the conductive pads being positioned on the active surface of the wafer, the process for fabricating bumps comprising the steps of:

• forming an adhesion layer onto the active surface of the wafer, the adhesion layer covering the conductive pads and the passivation layer, wherein the material of the adhesion layer includes aluminum;
• forming a barrier layer onto the adhesion layer, wherein the material of the barrier layer includes nickel-vanadium alloy;
• forming a wettable layer onto the barrier layer;
• forming a photoresist layer onto the wettable layer, wherein a plurality of openings are formed through the photoresist layer and expose the wettable layer;
• filling a solder matel into the openings of the photoresist layer and the solder material covering the wettable layer;
• removing the photoresist layer;
• performing etching processes to remove the wettable layer, the barrier layer and the adhesion layer that are exposed to the outside, the wettable layer, the barrier layer and the adhesion layer remaining under the solder material, wherein an etchant for etching the barrier layer includes sulfuric acid;
• and
• performing a reflow process to make the solder material into a ball-like shape.

A process for fabricating bumps on a wafer, the wafer having an active surface, the wafer being provided with a passivation layer and a plurality of conductive pads, both the passivation layer and the conductive pads being positioned on the active surface of the wafer, the process for fabricating bumps comprising the steps of:

• forming an adhesion layer onto the active surface of the wafer, the adhesion layer covering the conductive pads and the passivation layer, wherein the material of the adhesion layer includes titanium-wolfram alloy;
• forming a barrier layer onto the adhesion layer, wherein the material of the barrier layer includes nickel-vanadium alloy;
• forming a wettable layer onto the barrier layer;
• forming a photoresist layer onto the wettable layer, wherein a plurality of openings are formed through the photoresist layer and expose the wettable layer;
• filling a solder material into the openings of the photoresist layer and the solder material covering the wettable layer;
• removing the photoresist layer;
• performing etching processes to remove the wettable layer, the barrier layer and the adhesion layer that are exposed to the outside, the wettable layer, the barrier layer and the adhesion layer remaining under the solder material, wherein an etchant for etching the barrier layer includes sulfuric acid;
• and
• performing a reflow process to make the solder material into a ball-like shape.

A process for fabricating bumps on a wafer, the wafer having an active surface, the wafer being provided with a passivation layer and a plurality of conductive pads, both the passivation layer and the conductive pads being positioned on the active surface of the wafer, the process for fabricating bumps comprising the steps of:

• forming an adhesion layer onto the active surface of the wafer, the adhesion layer covering the conductive pads and the passivation layer, wherein the material of the adhesion layer includes chromium;
• forming a barrier layer onto the adhesion layer, wherein the material of the barrier layer includes nickel-vanadium alloy;
• forming a wettable layer onto the barrier layer;
• forming a photoresist layer onto the wettable layer, wherein a plurality of openings are formed through the photoresist layer and expose the wettable layer;
• filling a solder material into the openings of the photoresist layer and the solder material covering the wettable layer;
• removing the photoresist layer;
• performing etching processes to remove the wettable layer, the barrier layer and the adhesion layer that are exposed to the outside, the wettable layer, the barrier layer and the adhesion layer remaining under the solder material, wherein an etchant for etching the barrier layer includes sulfuric acid;
• and
• performing a reflow process to make the solder material into a ball-like shape.