International Business Machines Corporation

Other

Ultratech, Inc.

Invensas LLC

Donald W Henderson

Da-Yuan Shih

Sung Kwon Kang

Kamalesh K Srivastava

Lawrence P Lehman

James Spalik

Gareth Geoffrey Hougham

Brian Richard Sundlof

David V Caletka

Edward Frank Helinski

George Henry Thiel

Krishna Darbha

William E Bernier

Christian Lavoie

Charles Leon Arvin

Paul Alfred Lauro

Stephen L Buchwalter

Eric D Perfecto

Krystyna Waleria Semkow

Roy Arthur Carruthers

S Jay Chey

Peter Jeffrey Brofman

David Erle Houser

Ajay Prabhakar Giri

Leena Paivikki Buchwalter

Julien Sylvestre

Hsichang Liu

Jonathan H Griffith

Renee L Weisman

Michael J Sullivan

Eric H Laine

Luc L Belanger

Alexandre Blander

Isabelle Paquin

Valérie Anne Oberson

David R Di Milia

Richard P Ferlita

Mukta G Farooq

Evan G Colgan

Michael A Gaynes

William Louis Brodsky

Peter Alfred Gruber

Hilton T Toy

David L Edwards

Carlos Juan Sambucetti

Bruce Kenneth Furman

Frank Louis Pompeo

Steven Paul Ostrander

Glenn Graham Daves

Yu-Ting Cheng

Henry Atkinson Nye, Iii

Srinivasa S N Reddy

Karl J Puttlitz, Sr

Stefanie Ruth Chiras

Charles C Goldsmith

Stephen James Kilpatrick

Timothy A Gosselin

Daniel C Webster, Deceased

Sung-Kwon Kang

Edward J Burke

Jaimal M Williamson

Srinivasa Sn Reddy

Won K Choi

Sung K Kang

In one embodiment of the present invention, inert nano-sized particles having dimensions from 1 nm to 1,000 nm are added into a solder ball. The inert nano-sized particles may comprise metal oxides, metal nitrides, metal carbides, metal borides, etc. The inert nano-sized particles may be a single compound, or may be a metallic material having a coating of a different material. In another embodiment of the present invention, a small quantity of at least one elemental metal that forms stable high melting intermetallic compound with tin is added to a solder ball. The added at least one elemental metal forms precipitates of intermetallic compounds with tin, which are dispersed as fine particles in the solder.

Additives for grain fragmentation in Pb-free Sn-based solder

An interconnection structure suitable for flip-chip attachment of microelectronic device chips to packages, comprising a two, three or four layer ball-limiting metallurgy 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.

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

A solder joint comprising a solder capture pad on a substrate having a circuit; and a lead containing or a lead free solder selected from the group comprising Sn&#x2014;Ag&#x2014;Cu solder, Sn&#x2014;Cu solder and Sn&#x2014;Ag solder adhered to the solder capture pad; the solder selected from the group comprising between 0.1 and 6.0 per cent by weight Zn. A solder joint, comprising a solder capture pad on a substrate having a circuit; and a Sn&#x2014;Cu lead free solder adhered to the solder capture pad, the solder comprising between 0.1 and 6.0% by weight Zn. Formation of voids at an interface between the solder and the solder capture pad is suppressed. A method for forming solder joints using the solders.

Modification of solder alloy compositions to suppress interfacial void formation in solder joints

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

Briefly, a novel material process is disclosed wherein one or more nucleation modifiers are added, in trace amounts, to a lead-free tin-rich solder alloy to produce a solder composition with reduce or suppressed undercooling temperature characteristics. The modifier being a substance which facilitates the reduction of extreme anisotropic properties associated with body-centered-tetragonal tin based lead-free solder. The addition of the nucleation modifiers to the solder alloy does not materially effect the solder composition's melting point. As such, balls of solder with the nucleated composition freeze while other solder balls within the array remain in the melt. This effectively enables one substrate to be pinned to another substrate by one or more predetermined solder balls to secure the package while the remaining solder joints are in the liquid state. Further, the addition of a trace amount of nucleation sites within the composition facilitates control over the number, size, and orientations of primary intermetallic compounds in tin rich crystallite grains. Moreover, trace amounts of one or more solid and/or insoluble nucleating modifiers within a given volume of solder reduces the size of average crystallites within the composition.

Method and process for reducing undercooling in a lead-free tin-rich solder alloy

Briefly, a novel material process is disclosed wherein one or more nucleation modifiers are added, in trace amounts, to a lead-free tin-rich solder alloy to produce a solder composition with reduced or suppressed undercooling temperature characteristics. The modifier being a substance which facilitates the reduction of extreme anisotropic properties associated with body-centered-tetragonal tin based lead-free solder. The addition of the nucleation modifiers to the solder alloy does not materially effect the solder composition's melting point. As such, balls of solder with the nucleated composition freeze while other solder balls within the array remain in the melt. This effectively enables one substrate to be pinned to another substrate by one or more predetermined solder balls to secure the package while the remaining solder joints are in the liquid state.

Solder balls, such as, low melt C4 solder balls undergo volume expansion during reflow. Where the solder balls are encapsulated, expansion pressure can cause damage to device integrity. A volume expansion region in the semiconductor chip substrate beneath each of the solder balls accommodates volume expansion. Air-cushioned diaphgrams, deformable materials and non-wettable surfaces may be used to permit return of the solder during cooling to its original site. A porous medium with voids sufficient to accommodate expansion may also be used.

Method to accommodate increase in volume expansion during solder reflow

A ball-limiting metallurgy includes a substrate, a barrier layer formed over the substrate, an adhesion layer formed over the barrier layer, a first solderable layer formed over the adhesion layer, a diffusion barrier layer formed over the adhesion layer, and a second solderable layer formed over the diffusion barrier layer.

Ball limiting metallurgy, interconnection structure including the same, and method of forming an interconnection structure

Solder balls such as, low melt C4 solder balls, undergo volume expansion during reflow, such as may occur during attachment of chip modules to a PCB. Where the solder balls are encapsulated, expansion pressure can cause damage to device integrity. A volume expansion region in the semiconductor chip substrate beneath each of the solder balls accommodated this volume expansion. Air-cushioned diaphgrams, deformable materials and non-wettable surfaces may be used to permit return of the solder during cooling to its original site. A porous medium with voids sufficient to accommodate expansion may also be used.

Method of accommodating in volume expansion during solder reflow

A cooling system for an electronic component on a component carrier is provided. The system includes a frame, a spray manifold, and a sealing member. The frame has an opening and is connectable to the component carrier so that an annular area is defined between the opening and the electronic component. The spray manifold is sealed over the opening to define a spray area over a back surface of the electronic component. The spray manifold sprays a cooling fluid on the back surface. The sealing member seals the annular region so that input/output connectors on the component carrier are isolated from the cooling fluid.

Fluidic cooling systems and methods for electronic components

A method for protecting tin oxide coated solder surfaces against further oxidation and a method for fluxless solder joining of such surfaces is provided.

Solder protective coating and fluxless joining of flip chip devices on laminates with plated solder

A solder composition and associated method of formation. The solder composition comprises a substantially lead-free alloy that includes tin (Sn), silver (Ag), and copper. The tin has a weight percent concentration in the alloy of at least about 90%. The silver has a weight percent concentration X in the alloy. X is sufficiently small that formation of Ag Sn plates is substantially suppressed when the alloy in a liquefied state is being solidified by being cooled to a lower temperature at which the solid Sn phase is nucleated. This lower temperature corresponds to an undercooling &dgr;T relative to the eutectic melting temperature of the alloy. Alternatively, X may be about 4.0% or less, wherein the liquefied alloy is cooled at a cooling rate that is high enough to substantially suppress Ag Sn plate formation in the alloy. The copper has a weight percent concentration in the alloy not exceeding about 1.5%.

Lead-free tin-silver-copper alloy solder composition

Structure to accommodate increase in volume expansion during solder reflow

An electronic package is provided including a substrate, a device mounted on the substrate, and a solder member electrically coupling the device to the substrate. The package includes a dielectric material positioned substantially around the solder member which forms a physical connection between the substrate and the device. The volume of the solder member contracts during melting thereof to prevent failure of the physical connection and/or the electrical coupling between the substrate and the device.

Negative volume expansion lead-free electrical connection

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Ithaca, NY, United States of America

Donald W Henderson