Circuits Made Of Solid Aluminum: Unisys Is On The Trail

Unisys Corp. raised eyebrows two months ago by saying that it is considering a radical approach to making printed-circuit boards: putting the circuitry on solid aluminum sheets instead of laying copper patterns on a laminated base. What makes the idea especially novel is its source: the former Soviet republic of Belarus. By now, aluminum circuit boards should be coming off an experimental production line whose finishing touches were added on Aug. 6, says Thomas D. Watson, strategic planning director for electronic systems.

How can conductive circuits be created in solid aluminum? By surrounding the flat "wires" on the board with aluminum oxide, which is an electrical insulator--and which is easily formed by treating the boards with common citric acid. That eliminates the need for the highly toxic chemicals now used in processing circuit boards.

What's more, since aluminum oxide isn't a thermal insulator, the boards dissipate heat much faster, which means chips can be packed tighter without danger of frying. Someday, Watson speculates, even the chips themselves might be fabricated on aluminum to reduce the risk of overheating. That sounds as if Unisys is leaning toward licensing the technology from East/West Technology Partners Ltd., the Arlington (Va.) organization representing the Belarussians. But officially, that decision hasn't been made yet.

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