International Business Machines Corporation

Gary L Newman

James M Larnerd

Alan J Emerick

John P Simpson

Voya Rista Markovich

Michael Wozniak

Gerald Andrew Kiballa

Edward Cibulsky

John Francis Prikazsky

A technique for chemically planarizing an exposed surface of metal on a substrate to a pre-determined thickness is provided. The substrate has an exposed metal surface such as copper circuitry on a dielectric substrate which is to be planarized. Typically, this will be circuitization extending above a photoresist layer. A planarizing head is rotated against the substrate, with the planarizing head in contact with the metal surface on the substrate. A chemical etchant, essentially free of abrasive material, is continuously supplied to the interface between the metal surface and the planarizing head. The planarizing continues until a predetermined thickness of the metal has been reached. In circuit board manufacturing, this will form a surface co-planar with the photoresist. In some instances where significant height reduction is required, thus requiring significant metal removal, several passes of the substrate may be required or a device with multiple heads may be used. On all but the last pass or last head, the planarizing head may include a film of polyester impregnated with very fine grit, such as 15.mu. or less silicon carbide (SiC). However, on the final pass or head, a relatively hard surface roll, e.g., rubber, free of added grit, is used to ensure a planar surface free of gouges.

Method and apparatus for polishing metal surfaces

A method and apparatus for producing flush solder fill over recessed pins and over passage holes in circuitized substrates. A substrate carrying rack is immersed in a vessel of molten solder after it has been similarly immersed in a flux bath. While in the molten solder, the rack is vigorously agitated. The rack is then withdrawn from the molten solder and is pivoted upwardly while positioned over the molten solder. Simultaneously, an anvil is rotated from a home position to an impact position at precisely the correct moment. With the solder still molten on the substrate surfaces, the rack is then permitted to descend and is positively biased to strike the anvil thereby dislodging any excess molten solder. A unique supporting arrangement for the rack insures that only a minimum of mass acutally impacts against the anvil while insuring the effectiveness of the operation. Each cantilevered arm from which a rack is suspended is temporarily supported during the impacting operation after which the support member is withdrawn. Also, a solder pot of unique design and operation is provided to assure rapid, complete heating of substrates while eliminating contamination thereof by dross and oxides.

Solder leveling method and apparatus

A method and apparatus for producing flush solder fill over recessed pins and over passage holes in circuitized substrates. A substrate carrying rack is immersed in a vessel of molten solder after it has been similarly immersed in a flux bath. While in the molten solder, the rack is vigorously agitated. The rack is then withdrawn from the molten solder and is pivoted upwardly while positioned over the molten solder. Simultaneously, an anvil is rotated from a home position to an impact position at precisely the correct moment. With the solder still molten on the substrate surfaces, the rack is then permitted to descend and is positively biased to strike the anvil thereby dislodging any excess molten solder. A unique supporting arrangement for the rack insures that only a minimum of mass actually impacts against the anvil while insuring the effectiveness of the operation. Each cantilevered arm from which a rack is suspended is temporarily supported during the impacting operation after which the support member is withdrawn. Also, a solder pot of unique design and operation is provided to assure rapid, complete heating of substrates while eliminating contamination thereof by dross and oxides.

Growing community of inventors

Little Meadows, PA, United States of America

Gary L Newman