Lucent Technologies Inc.

Agere Systems Inc.

Te-Sung Wu

Henry Hon Law

Sungho Jin

Thomas H Tiefel

John Thomson, Jr

Lynn Frances Schneemeyer

Apurba Roy

Vincent George Lambrecht, Jr

Michael D Evans

Tae Yong Kim

A process for the metalization of substrates is disclosed. The metal either forms a coating over the entire substrate, or it is patternwise deposited on the substrate surface. Metal is patternwise formed on the substrate either by forming a pattern of resist material on the substrate and depositing the material in the interstices defined by the pattern or by forming a patterned resist layer over a metal layer and transferring the pattern into the substrate using conventional techniques. The patterned resist layer is formed on the substrate using conventional techniques. The substrate is treated with reagents that promote the electroless plating of metal on the substrate surface. If the resist material has been previously formed on the substrate surface, the substrate surface is then dried. The remaining resist is then removed from the substrate surface. The substrate surface is then exposed to an electroless plating bath to form nickel onto those portions of the substrate surface that were treated with the sensitizing and activating solutions. The substrate is then heated to at least 180&deg; C. Additional layers of metal are formed on the substrate. After the additional layers are so formed, the substrate is again heated to a temperature of at least about 180&deg; C. after each layer is so formed.

Process for the electroless deposition of metal on a substrate

This invention is predicated on the discovery by the present applicants that boric acid in conventional nickel plating baths is responsible for excessive lateral growth in the electroplating of nickel on nickel ferrite substrates. While nickel baths without boric acid do not yield acceptable electrodeposits, the boric acid interacts with the ferrite substrate to cause excessive lateral growth. Applicants further discovered that by eliminating the boric acid and adding another acidic plating buffer such as citric acid, one can obtain isotropic nickel plating and produce a wire-bondable surface.

Electroplating of nickel on nickel ferrite devices

The thickness uniformity of a plated metal layer inside a via hole can be enhanced by intersecting a conductive via with an insulating aperture before plating. The new via configuration improves the mass transfer of the plating. It is believed that the apertures lower the local solution ohmic resistance near the via holes. The method can be applied to the manufacture of a wide variety of circuit boards.

Method for fabricating highly conductive vias

The present invention provides a method for metallizing a ceramic surface comprising a ferrite through a surface reduction treatment. A ceramic surface comprising a ferrite is heated. At least a portion of the ferrite is contacted with a gaseous reducing agent to create a metallic region by removing oxygen from the ferrite. The surface is cooled and, optionally, post-treated to enhance adhesion of the metallic region. Typical gaseous reducing agents are hydrogen, forming gas, and ammonia while typical ferrites are nickel-zinc ferrites and manganese-zinc ferrites. To form patterned regions, portions of the substrate are masked or portions of the reduced layer are removed.

Metallization of ferrites through surface reduction

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New Providence, NJ, United States of America

Te-Sung Wu