Minnesota Mining and Manufacturing Company

Howard Edwin Evans

Randolph D Schueller

Anthony R Plepys

John D Geissinger

A ball grid array (BGA) package is provided in which the stiffener of the BGA may also be utilized as a conductive layer. A TAB tape is adhered to the stiffener by an adhesive and both the TAB tape and the adhesive may have vias which open to the stiffener. Conductive plugs which may be formed of solder paste, conductive adhesives, or the like may then be filled in the vias to provide electrical connection from the TAB tape to the stiffener. The vias may be located adjacent to solder ball locations. The TAB tape may include multiple conductor layers or multiple layers of single conductive layer TAB tape may be stacked upon each other to provide additional circuit routing. Further, the TAB tape layers may also be combined with the use of metal foil layers.

Multi-layer interconnect sutructure for ball grid arrays

A tape ball grid array package reverses the usual attachment of flexible circuitry to a stiffener so that the circuit traces face the stiffener rather than away from the stiffener as is conventional. This construction allows the elimination of a previously necessary solder mask and so reduces the cost to produce the package.

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Austin, TX, United States of America

Howard Edwin Evans