Method of making a low fabrication cost, high performance, high reliability chip scale package

A method for forming a metal bump on a semiconductor surface, comprising the steps of:

• providing a semiconductor surface, at least one contact pad having been provided in or over said semiconductor surface, a layer of passivation having been deposited over said semiconductor surface, a layer of dielectric having been deposited over said layer of passivation, said layers of dielectric and passivation having been patterned and etched creating at least one opening through said layers of dielectric and passivation, said at least one opening through said layers of dielectric and passivation being aligned with said at least one contact pad, exposing said at least one contact pad;
• depositing a layer of conductive material over said layer of dielectric, including said at least one contact pad, said layer of conductive material comprising a material selected from the group consisting of barrier layer material and seed layer material;
• forming a first metal deposition mask over said layer of conductive material, said first metal deposition mask exposing said layer of conductive material over a surface area that aligns with said at least one contact pad and, contiguous therewith, over a surface area that is adjacent to said at least one contact pad and emanating in one direction from said at least one contact pad;
• first electroplating a first layer of metal over said layer of conductive material in accordance with said first metal deposition mask, said first electroplating creating a layer of re-routing metal over said layer of conductive material;
• removing said first metal deposition mask from said layer of conductive material;
• forming a second metal deposition,mask over said layer of re-routing metal, said second metal deposition mask exposing said layer of re-routing metal over said surface area of said layer of re-routing metal that is adjacent to said at least one contact pad and emanating in one direction from said at least one contact pad;
• second electroplating a second layer of metal over said layer of re-routing metal in accordance with said second metal deposition mask, said second electroplating creating a layer of pillar metal over said re-routing metal after which a layer of solder compound is electroplated over said pillar metal;
• removing said second metal deposition mask from said layer of re-routing metal, exposing said layer of conductive material and said re-routing metal;
• and
• etching said layer of conductive material using said layer of re-routing metal as a mask, simultaneously reducing a diameter of said second electroplated pillar metal by an amount.