Etched glass solder bump transfer for flip chip integrated circuit devices
AssigneeInternational Business Machines Corporation
InventorsSteven A. Cordes, Peter Alfred Gruber, Egon Max Kummer, Stephen Roux, Carlos Juan Sambucetti, James Louis Speidell
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Abstract
A precise volume, precisely registerable carrier is provided for use with injection molding for producing integrated circuit bump contacts in the “flip chip” technology. A hemispherical cavity is produced by etching through and undercutting a registered opening into a transparent carrier. The hemispherical cavity has related specific volume and visible peripheral shape that permits simple optical quality control when the injection molding operation has filled the cavity and simple optical registration for fusing to the pads on the integrated circuit.
Claims12
The method of providing bump contacts for a flip chip integrated circuit having contact pads on a surface,
- comprising the steps of:
- forming, in an approximately flat, chemical etchant responsive, transparent, glass carrier member, a distribution of contact volume quantities of solder in cavities each exposed at a surface of said carrier,
- said distribution corresponding to a distribution of said contact pads on said integrated circuit,
- said forming step of said distribution being achieved by the steps of,
- providing a hole in a glass etchant resistant coating on said glass carrier member at the location of each member of said distribution,
- etching through said hole a hemispherical cavity that undercuts said coating around said hole,
- aligning said distribution of pads with said distribution of exposed contact volume quantities by optically centering said pads over said contact volumes as viewed employing said carrier transparency, and,
- applying a heat cycle sufficient to fuse said distributions of pads and contact volume quantities.
Dependencies are inferred from the claim text.