International Business Machines Corporation
Fabrication method of high aspect ratio solder bumping with stud bump and injection molded solder, and flip chip joining with the solder bump

Abstract:

A technique for fabricating bumps on a substrate is disclosed. A substrate that includes a set of pads formed on a surface thereof is prepared. A bump base is formed on each pad of the substrate. Each bump base has a tip extending outwardly from the corresponding pad. A resist layer is patterned on the substrate to have a set of holes through the resist layer. Each hole is aligned with the corresponding pad and having space configured to surround the tip of the bump base formed on the corresponding pad. The set of the holes in the resist layer is filled with conductive material to form a set of bumps on the substrate. The resist layer is stripped from the substrate with leaving the set of the bumps.