Method for forming solder bumps for flip-chip bonding by using perpendicularly laid masking strips

Abstract

A method for forming solder bumps for a flip-chip bonding process wherein the bumps have substantially the same height and structures formed by the method are described. In the method, a pre-processed semiconductor substrate that has a plurality of metal traces formed on a top surface is first provided. At least two solder non-wettable masking strips are then deposited on top of and perpendicular to the plurality of metal traces. The at least two solder non-wettable masking strips are deposited spaced-apart at a predetermined spacing sufficient for forming a bond pad therein-between on the plurality of metal traces. Finally, a solder material is deposited onto the bond pads forming solder bumps which are then reflown into solder balls.

Dependencies are inferred from the claim text.