International Business Machines Corporation

Nicholas G Koopman

Kamalesh K Srivastava

Paul A Totta

Sudipta Kumar Ray

James Gardner Ryan

Erick G Walton

Judith Marie Roldan

Birendra N Agarwala

Arthur Bross

Karl J Puttlitz, Sr

Chin-An Chang

Aziz M Ahsan

Adolf E Wirsing

Helen L Yeh

Li-Chung Lee

Joseph G Schaefer

Somnath Bhattacharya

Vincent C Marcotte

Steven Strickman

Mark F Chadurjian

Dudley A Chance

Chester C Oldakowski

Shih-Ming Hu

Stephen Teed

The present invention relates generally to a new interconnection and a method for making the same, and more particularly, to an elongated solder interconnection and a method for making the same. On an electronic carrier, a pad is formed on which a solder mass is deposited and capped with a metal layer, thereby forming an elongated solder interconnection. A further elongated solder interconnection can now be formed by forming a second solder mass on the first solder mass that has been capped by a metal layer. Additional elongated solder interconnection can be formed by capping the preceding solder mass and/or the last solder mass with a metal capping layer. Alternatively, the encapsulating layer can be in the form of a sidewall spacer formed on the sidewalls of the solder mass.

Method of forming dual height solder interconnections

The fluxless bonding in a reducing atmosphere of integrated circuit contacts containing copper is enhanced using a layer of 200 to 1500 Angstrom thick palladium which inhibits copper oxide formation before fusion and reduces all oxides to promote wetting during fusion.

Palladium enhanced soldering and bonding of semiconductor device contacts

Solder mass having conductive encapsulating arrangement

Palladium enhanced fluxless soldering and bonding of semiconductor

A heat resistant brazing alloy of a major amount of gold, a lesser amount of indium and a minor amount of tin. The alloy is particularly suited for use in bonding electrical components to chip carrying substrates which are to be reworked.

Process of brazing using low temperature braze alloy of gold-indium tin

The top surface metallurgy of LSI chip carriers is improved by multiple and phased interface of metal layers which enable such metallurgies to be suitable for joining by solder reflow and wire bonding techniques. The modifications result in separating the solder bonding metallurgy from the fan-out conductor metallurgy with an intermediate layer of a metal such as Cr or Ti which prevents the formation of intermetallic alloys which are mechanically weak or brittle and tend to fracture because of thermal fatigue stresses caused by thermal cycling during either multiple (up to 50) solder bonding reflow operations or operation of the circuit. The fan-out metallurgy conductors are preferably composed of Cr-Cu-Cr layers covered by at least one upper metal layer which is separated from the Cu of the conductor by means of a metal such as phased layers of Cr or Ti deposited before the other upper metal layer or layers. Solder ball bonding surfaces are composed of additional metal in the form of Au, Cu and Ni. The solderless bonding surfaces are composed of a metal selected from Au, Cr, Ti, Al and Co.

Layered metal film structures for LSI chip carriers adapted for solder

A controlled geometric configuration of contact pads for securing solder mounds to an integrated circuit chip which reduces cracking of brittle passivating coatings in fabrication of components.

Solder mound formation on substrates

Extraction of non-lead components (e.g. tin, indium, etc.) from solder joints with monocarboxylic acids of alkylated hydrophenanthrene nuclei to increase the lead content of the solder joints.

Process for in-situ modification of solder comopsition

A circuit package exhibiting an excellent heat transfer path from a semiconductor chip or other heat-generating device to the heat-sink can or cover of the package. A heat-conducting pad is metallurgically bonded to either said cover or a surface of said device; the pad is also separably attached, but metallurgically unbonded, to the other. In one preferred embodiment, a readily deformable metal or alloy, such as indium, is metallurgically bonded to a limited central region of the heat sink cover. The deformable metal is separably attached to a major surface of the chip so that there is no stress between the chip or its joints and the solder during the electrical operation of the chip when it generates heat. The preferred method of fabrication involves the mechanical deformation of a mass of solder against the back side of the chip, after the solder has been metallurgically bonded to heat sink. The process may be accomplished either at high or low temperatures, depending upon the solder composition and the relative strength of the leads which join the chip to conductive lands on its supportive substrate.

Conduction-cooled circuit package

A method for making a circuit package which exhibits an excellent heat transfer path from a semiconductor chip or other heat generating device to the heat sink can or cover of the package. A heat conducting pad is placed in proximate relationship to either the heat sink or to a surface of the chip and is metallurgically bonded to the other. In one of the preferred embodiments a low melting point solder, such as indium or an alloy thereof, is metallurgically bonded to the inside of the heat sink cover in a limited central region thereof. The solder is then positioned adjacent the chip and reflowed to substantially fill in the gap between the solder and the chip, but with no stress between the chip and the solder. The assembly exhibits excellent heat transfer from the chip to the cover and any associated heat dissipating structures. The preferred method involves the reflow of a mass of solder against the back side of the chip, which has previously been solder-bonded on the front side to conductors on the surface of an alumina substrate.

Method for making conduction-cooled circuit package

Method of making conduction-cooled circuit package

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Hopewell Junction, NY, United States of America

Nicholas G Koopman