International Business Machines Corporation

Gore Enterprise Holdings, Inc.

W. L. Gore & Associates, Inc.

Donald R Banks

John Saunders Corbin, Jr

Paul J Fischer

Mark F Sylvester

John Acocella

Karl G Hoebener

Joseph Angelo Benenati

David P Watson

Thomas Caulfield

William G Petefish

Ronald G Pofahl

Joseph G Ameen

Daniel D Johnson

Carmine G Meola

High melting temperature Pb/Sn 95/5 solder balls are connected to copper pads on the bottom of a ceramic chip carrier substrate by low melting temperature eutectic Pb/Sn solder. The connection is made by quick reflow to prevent dissolving Pb into the eutectic solder and raising its melting temperature. Then the module is placed on a fiberglass-epoxy circuit board with the solder balls on eutectic Pb/Sn solder bumps on copper pads of the board. The structure is reflowed to simultaneously melt the solder on both sides of the balls to allow each ball to center between the carrier pad and circuit board pad to form a more symmetric joint. This process results in structure that are more reliable under high temperature cycling. Also, to further improve reliability, the balls are made as large as the I/O spacing allows without bridging beam on balls; the two pads are about the same size with more solder on the smaller pad; the pads are at least 75% of the ball diameter; and the eutectic joints are made as large as possible without bridging between pads. For reliability at even higher temperature cycles or larger substrate sizes columns are used instead of balls.

Solder ball connections and assembly process

The present invention generally relates to the field of integrated circuit chip packaging. More particularly, the present invention relates to methods of manufacturing integrated circuit chip packages, and methods for electrically connecting and bonding or attaching semiconductor devices to an integrated circuit chip.

Method for assembling an integrated circuit chip package having an

Method for assembling an integrated circuit chip package having at least

A metallurgical interconnect composite is provided defined by a compliant, metallurgical, open cell, porous substrate which has a plurality of Z-axis conductive pathways extending from one side of the substrate to the other side. Each conductive pathway terminates in a solder covered surface area.

Metallurgical interconnect composite

Two substrates are produced each with a planar, mirror-image matrix of metal contacts in a surface wiring layer. The substrates are positioned with the matrices in parallel confrontation which defines pairs of confronting contacts. A metal ball is positioned between each pair of contacts with a respective volume of joining material between the ball and each of the two respective contacts. The volumes of joining material are simultaneously melted to allow surface tension to align the substrates and to accurately center the balls between each respective pairs of contacts in a plane defines by the matrix of balls.

Solder ball interconnected assembly

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Eau Claire, WI, United States of America

Donald R Banks