International Business Machines Corporation

Craig W Richards

Raymond Thomas Galasco

Bonnie S McClure

A method for forming a copper-Invar-copper (CIC) laminate having an intermetallic layer of negligible thickness, and a structure associated with the CIC laminate. Starting with a block of Invar, the method includes a cleaning step followed by an electroplating step. The cleaning step electrochemically cleans the block of Invar with an acid solution while applying a negative voltage bias to the block of Invar. The electroplating step electroplates copper on the block of Invar, resulting in the block of Invar being sandwiched between two layers of copper, such that an intermetallic layer of zero or negligible thickness is disposed between the block of Invar and each layer of copper. Each layer of copper has a uniform thickness. If the starting block of Invar contains a through hole, then the electroplating step will plate a ring of copper on the through hole wall. The ring of copper makes a seamless connection with the two layers of copper, because the ring of copper and the two layers of copper each have the same grain structure.

Copper plated invar with acid preclean

An electronic structure that includes a copper-Invar-copper (CIC) laminate of negligible thickness, such as a thickness not exceeding about 0.5 microns. The electronic structure may have a via passes through the CIC laminate such that the via is plated with a ring of copper. The ring of copper and the copper in the CIC laminate may have about the same grain structure.

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Chenango Forks, NY, United States of America

Craig W Richards