International Business Machines Corporation

Ronald Maurice Fraga

Sudipta Kumar Ray

Gordon J Robbins

Robert Charles Dockerty

Ciro Neal Ramirez

Charles Levern Reynolds, Jr

Structure and method for reinforcing a solder column grid array attachment of a ceramic or the like substrate to a printed circuit board, the reinforcement providing support for a heat sink which is bonded or affixed by pressure to a structural element of the substrate. In one form, the invention involves the concurrent formation of materially larger solder columns along the perimeter of the substrate in conjunction with the array of thin electrically interconnecting solder columns on the substrate. The reinforcing and electrical signal columns are thereafter aligned and attached by solder reflow to a corresponding pattern of pads on the printed circuit board. The heat sink is thermally connected to a structural element of the substrate by bonding or mechanical compression. Stresses in the solder columns caused by heat sink compressive forces or vibration induced flexing are materially decreased without adding complex or unique manufacturing operations.

Column grid array substrate attachment with heat sink stress relief

Supporting structure for a ball grid array surface mounted integrated circuit device composed of support solder formed at selective corner locations on the ball grid array surface of the integrated circuit device. In one form, L-shaped patterns of high melting temperature solder are formed along the axes defined by the ball grid array and are characterized in that cross sections of the L-shaped pattern match that of the solder balls along one axis, and represent a continuum of solder between solder ball locations along the other axis. Support solder can be added where necessary to provide both structural reinforcement and thermal conduction. Control of the cross section of the support solder ensures that surface tension effects of the molten low temperature reflow solder used to connect the integrated circuit device does not materially change the final relative spacing between the integrated circuit device balls and the underlying printed circuit board contacts.

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Pflugerville, TX, United States of America

Ronald Maurice Fraga