International Business Machines Corporation

Balaram Ghosal

Keith E Fogel

Paul Alfred Lauro

Da-Yuan Shih

Sung Kwon Kang

Henry Atkinson Nye, Iii

Donna S Zupanski-Nielsen

Stephen James Kilpatrick

Peter Jeffrey Brofman

Raymond A Jackson

William Edward Sablinski

Karl J Puttlitz, Sr

Nunzio DiPaolo

Kathleen Ann Lidestri

Kim H Ruffing

Roy Rongqing Yu

Eric D Perfecto

Chandrika Prasad

James Kuss

Matthew Wayne Oonk

Jeffrey B Danielson

An interconnection structure suitable for flip-chip attachment of microelectronic device chips to packages, comprising a two, three or four layer ball-limiting composition including an adhesion/reaction barrier layer, and having a solder wettable layer reactive with components of a tin-containing lead free solder, so that the solderable layer can be totally consumed during soldering, but a barrier layer remains after being placed in contact with the lead free solder during soldering. One or more lead-free solder balls is selectively situated on the solder wetting layer, the lead-free solder balls comprising tin as a predominant component and one or more alloying components. With a two-layer ball-limiting composition comprising an adhesion/reaction barrier layer, wherein the adhesion/reaction barrier layer serves both as an adhesion layer and a reaction barrier layer, the adhesion/reaction barrier layer can be comprised of a material selected from the group consisting of Zr and ZrN.

Interconnections for flip-chip using lead-free solders and having reaction barrier layers

An interconnection structure suitable for flip-chip attachment of microelectronic device chips to packages, comprising a two, three or four layer ball-limiting composition including an adhesion/reaction barrier layer, and having a solder wettable layer reactive with components of a tin-containing lead free solder, so that the solderable layer can be totally consumed during soldering, but a barrier layer remains after being placed in contact with the lead free solder during soldering. One or more lead-free solder balls is selectively situated on the solder wetting layer, the lead-free solder balls comprising tin as a predominant component and one or more alloying components.

A thin film transfer join process in which a multilevel thin film structure is formed on a carrier, the multilevel thin film structure is joined to a final substrate and then the carrier is removed. Once the carrier is removed, the dielectric material and metallic material that were once joined to the carrier are now exposed. The dielectric material is then etched back so that the exposed metallic material protrudes beyond the dielectric material. Also disclosed is a module made by the foregoing process.

Thin film transfer join process and multilevel thin film module

An electronic component having a socketable bump grid array comprising shaped-solder coated metallic spheres is provided by a method which comprises positioning solder coated metal spheres in an aligning device having a plurality of openings corresponding to the array, the openings being tapered preferably in the form of a truncated cone with the base of the cone being at the upper surface of the aligning device and having a diameter larger than the diameter of the solder coated metal sphere. The opening is configured so that a sphere positioned in the opening extends partially above the upper surface of the aligning device. The pads of the substrate are then contacted with the positioned spheres and, when the solder is reflowed, the solder forms a bond between the conductive layer on the substrate in contact with the solder-coated metal sphere and takes the shape of the aligning device and which maintains a solder coating on the whole surface of the metal sphere. An apparatus is also provided for making such a socketable bump grid array.

Socketable bump grid array shaped-solder on copper spheres

An electronic component having a socketable bump grid array comprising shaped-solder coated metallic spheres is provided by a method which comprises positioning solder coated metal spheres in an aligning device having a plurality of opening corresponding to the array, the openings being tapered preferably in the form of a truncated cone with the base of the cone being at the upper surface of the aligning device and having a diameter larger than the diameter of the solder coated metal sphere. The opening is configured so that a sphere positioned in the opening extends partially above the upper surface of the aligning device. The pads of the substrate are then contacted with the positioned spheres and, when the solder is reflowed, the solder forms a bond between the conductive layer on the substrate in contact with the solder-coated metal sphere and takes the shape of the aligning device and which maintains a solder coating on the whole surface of the metal sphere. An apparatus is also provided for making such a socketable bump grid array.

An outer coating of an electrically conductive material having low wetability with respect to solder is deposited over a gold coating previously deposited on an electrical contact element. After soldering the contact element to a substrate, the portion of the outer coating not covered by solder is removed from the contact element. The method of joining a contact element to a substrate in accordance with the present invention effectively solves the problem of solder climb to the critical contact area of the element without the need to provide masking or apply plating resist coatings to selected areas of the element.

Method of joining an electrical contact element to a substrate

A member having a shank is selectively coated with a material such as a metal by loosely sliding a washer made of a material such as a thermoplastic or thermosetting polymer onto the shank, securing the washer such that the washer is in intimate contact with the shank, and immersing at least a portion of the member into at least one coating bath so that a portion of the member is coated and the portion of the shank in contact with the washer is not coated. The member can be an input/output pin for an electronic device and the coating can be applied by methods such as electroless plating or electrolytic plating.

Selectively coated member having a shank with a portion masked

Method for selectively coating a member having a shank by masking a

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Fishkill, NY, United States of America

Balaram Ghosal