| abstract |
A method of forming an integrated circuit package at the wafer level. The integrated circuit package occupies a minimum amount of space on an end-use printed circuit board. Solder bumps, or conductive adhesive, is deposited on the metallized wirebond pads on the top surface of a silicon wafer. An underfill-flux material is deposited over the wafer and the solder bumps. A pre-fabricated interposer substrate, made of metal circuitry and a dielectric base, has a plurality of metallized through-holes which are aligned with the solder bumps. The wafer/interposer assembly is reflowed, or cured, to form the electrical connection between the circuitry on the interposer layer and the circuitry on the wafer. Solder balls are then placed on the metal pad openings on the interposer substrate and are reflowed to form a wafer-level BGA structure. The wafer-level BGA structure is then cut into individual BGA chip packages. |