International Business Machines Corporation

Walter P Pawlowski

John J Glenning

Stephen L Buchwalter

Martin J Goldberg

Stephen L Tisdale

Linda C Matthew

Caroline A Kovac

Kenneth G Sakorafos

Gareth Geoffrey Hougham

Alfred Viehbeck

Claudius Feger

Natalie Barbara Feilchenfeld

Peter Slota, Jr

John J Ritsko

Paul George Rickerl

Kurt R Grebe

Stephen Joseph Fuerniss

Steven E Molis

Michael R Scheuermann

Morris Anschel

Randy William Snyder

Steven L Bard

Mark J Schadt

Giana M Phelan

William A Donson

Aldred Viehbeck

Caryn J Johnson

Certain organic polymeric materials are capable of reversibly accepting or donating electrons from a reducing entity. The redox sites in the polymer accept electrons and, as a result, a change in the properties of the polymer occurs. This change is useful in modifying or etching the polymeric material The material can be modified by incorporation of metallic seeds into the material at a controlled depth. The seeds are incorporated by interaction of cations of the metals with the redox sites in the polymer, which cause the reduction of the cations to form the neutral metallic seeds. Subsequent exposure of the polymeric material containing the seeds to an electroless bath causes further deposition of metal having the desirable characteristic of good adhesion to the polymeric material. Etching of the polymeric material can be carried out as a result of an increase in solubility of the polymer in aprotic solvents when its redox sites have accepted electrons. The increased solubility allows openings to be etched in certain areas of the polymeric material that have been reduced, leaving other areas unchanged.

Method for conditioning an organic polymeric material

Certain organic polymeric materials are capable of reversibly accepting or donating electrons from a reducing entity. The redox sites in the polymer accept electrons and, as a result, a change in the properties of the polymer occurs. This change is useful in modifying or etching the polymeric material. The material can be modified by incorporation of metallic seeds into the material at a controlled depth. The seeds are incorporated by interaction of cations of the metals with the redox sites in the polymer, which cause the reduction of the cations to form the neutral metallic seeds. Subsequent exposure of the polymeric material containing the seeds to an electroless bath causes further deposition of metal having the desirable characteristic of good adhesion to the polymeric material. Etching of the polymeric material can be carried out as a result of an increase in solubility of the polymer in aprotic solvents when its redox sites have accepted electrons. The increased solubility allows openings to be etched in certain areas of the polymeric material that have been reduced, leaving other areas unchanged.

Method for etching an organic polymeric material

Disclosed is a method of fabricating a microelectronic package, especially a microelectronic package having copper circuitization on a dielectric substrate. The method includes the steps of depositing a chromium adhesion layer on the dielectric substrate, depositing a copper seed layer on the chromium adhesion layer, depositing photoresist on the copper seed layer, imaging and developing the photoresist, and forming a pattern of copper circuitization on the selected portions of the send copper layer. The chromium adhesion layer material is removed from the dielectric substrate by contacting the chromium adhesion layer with aqueous sulfuric acid electrolyte, while maintaining the chromium adhesion layer electrolytically in series with a counterelectrode, and maintaining the chromium adhesion layer anodic with respect to the counterelectrode. The chromium adhesion layer material is oxidized to soluble Cr.sup.+3, while substantially avoiding formation of Cr.sup.+6.

Circuitization of polymeric circuit boards with galvanic removal of

A process is provided for improving the surface properties of polyimide articles which contain significant amounts of transimide. The surface of the polyimide containing the transimide is first treated with a base to convert the surface layer of both the polyimides and the transimides to polyamic salt. Thereafter the surface layer of the converted polyamic salt is treated with an acid to convert the layer to a polyamic acid. This is followed by a cure preferably in infrared radiation at a sufficiently rapid rate to prevent the formation of any significant amounts of transimide and provide only polyimide. Following this treatment metallization is applied to the improved surface layer.

Process for treating the surface of polyimides to improve properties to

A polyimide pattern is formed on a substrate by providing a layer of photosensitive polyimide precursor containing the polyimide precursor and a compound having a photosensitive group on the substrate and prebaking the layer. The layer is then exposed imagewise to actinic radiation through a photomask to form an exposed image pattern of the polyimide precursor in the layer. The unexposed areas of the layer are removed using a liquid developer and the exposed image pattern is cured by heating. In one aspect of the present invention, the prebaking step employs a judicious selection of times and temperature to eliminate the problem of formation of a white residue that occurs from using prior art prebake procedures. In another aspect of the present invention, a particular liquid developer composition is employed to facilitate the formation of sloped vias in the polyimide. In another aspect of the present invention, a particular range of exposure wavelength(s) is employed to obtain smooth walled vias.

Forming a polymide pattern on a substrate

A fully cured or substantially fully cured polyimide is etched by contacting the imide with an aqueous solution of a metal hydroxide such as an alkali metal or alkali earth hydroxide and a metallic compound selected from metal carbonates, sulfates and phosphates. The presence of the carbonate, sulfate or phosphare reduces the undercutting of a resist pattern on the polyimide.

Wet etching of cured polyimide

Polyimide is etched by contacting the polyimide with an aqueous solution of a metal hydroxide followed by contact with an acid followed by contact with an aqueous solution of a metal hydroxide. Etching of chemically cured polyimide can be enhanced by employing a presoaking in hot water. Also, partially etched chemically cured polyimide is removed with a concentrated acid solution. In preparing a metal coated polyimide structure for subsequent gold plating, two flash etching steps with the polyimide etch between are employed after developing the photoresist.

Wet etching of thermally or chemically cured polyimide

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Endicott, NY, United States of America

Walter P Pawlowski