International Business Machines Corporation

Jennifer Rebecca Sweterlitsch

Charles Gerard Woychik

Mark Vincent Pierson

Thurston Bryce Youngs, Jr

A flexible, compliant layer of a single low modulus material for connecting a chip die directly to a circuit card without encapsulation. The flexible compliant layer provides stress relief caused by CTE thermal mismatch in chip die and circuit card. An array of copper plated vias are formed in said compliant layer with each via terminating on opposing surfaces of the layer in copper pads. Rather than copper, other metals, such as gold or nickel, may also be used. An array of holes may be positioned between said array of vias to provide additional resiliency. The plated vias may be angled with respect to said opposing surfaces to allow additional vertical and horizontal stress relief. Connection of the pads on one surface to high melt C-4 solder balls or columns on a chip die results in solder filled vias. Low melt solder connection of the pads on the other surface to a circuit card allows non-destructive rework of the cards.

Methods of making and using a floating interposer

A space-saving integrated circuit package employs two printed circuit boards joined together, the upper board having an integrated circuit attached by flip-chip technology and the lower board having a cavity for holding an integrated circuit that is located beneath the upper integrated circuit, the lower integrated circuit being bonded to the bottom of the upper board below the upper integrated circuit and electrically connected to wiring on the lower surface of the lower board by wire bond connections.

Growing community of inventors

Vestal, NY, United States of America

Jennifer Rebecca Sweterlitsch