International Business Machines Corporation

Scott Ira Langenthal

John Ulrich Knickerbocker

Richard Francis Indyk

Benjamin V Fasano

Sudipta Kumar Ray

Peter Jeffrey Brofman

Kathleen Ann Stalter

Sundar M Kamath

Shaji Farooq

Srinivasa S Reddy

Rao Venkateswara Vallabhaneni

Srinivasa S N Reddy

David H Gabriels

Thomas Weiss

Charles Hampton Perry

Thomas Edward Lombardi

Lewis Sigmund Goldmann

Donald Rene Wall

Daniel George Berger

Yuet-Ying Yu

Daniel P O'Connor

Richard A Shelleman

Terence W Spoor

Camille Proietti Bowne

Shaji Faroon

Shaji Faroog

A pre-thermal reflown dielectric interposer having a plurality of vias traversing through the interposer which correspond to the I/O pads on a chip and substrate. Cone shaped solder elements reside within the vias, whereby these solder elements are cone shaped prior to thermal reflow to permit a reduced force for allowing some non-planarity for joining the chip to the substrate. The interposer may comprise a polyester film, glass, alumina, polyimide, a heat curable polymer or an inorganic powder filler in an organic material. The interposer may also have an adhesive or adhesive layers disposed on the linear surfaces thereof. The present pre-thermal reflown interposer prohibits contact between the solder joints by isolating each of the joints and corresponding bonding pads, as well as preventing over compression of the solder joints by acting as a stand off.

Dielectric interposer for chip to substrate soldering

A device for preventing short circuits between solder joints in flip chip packaging. The dielectric interposer has a plurality of apertures or vias which correspond to the I/O pads on a chip and substrate. Preferably, the interposer comprises a polyester film, glass, alumina, polyimide, a heat curable polymer or an inorganic powder filler in an organic material. More preferably, the interposer contains an adhesive or has adhesive layers disposed on the linear surfaces of the interposer. Cone shaped solder elements are formed within the apertures of the interposer. The dielectric interposer is positioned between a chip and substrate in an electronic module and thermally reflowed to create an electrical and mechanical interconnection. The interposer prohibits contact between the solder joints by isolating each of the joints and corresponding bonding pads. The interposer also prevents over compression of the solder joints by acting as a stand off.

A method of forming non-spherically shaped solder interconnects, preferably conical, for attachment of electronic components in an electronic module. Preferably, the solder interconnects of the present invention are cone shaped and comprise of depositing a first solder followed by a second solder having a lower reflow temperature than the first solder. Warm placement of the electronic component at a somewhat elevated temperature than room temperature but less than the solder reflow temperature reduces the force required during placement of a semiconductor chip to a substrate. After warm placement, reflow of the module occurs at the lower reflow temperature of the second solder. The conical shape of the solder interconnects are formed by a heated coining die which may also coin a portion of the interconnects with flat surfaces for stand-offs. The ability of the cone shaped solder interconnects to meet the opposing surface of a chip or substrate at different heights accommodates the camber typically associated with chip and substrate surfaces.

Process for forming cone shaped solder for chip interconnection

A self scrubbing buckling beam contactor for contacting an array of pads positioned on a device under test is described. The contactor consists of three insulating dies: a top, an offset and a lower die separated from each other by an insulated spacer of variable thickness. Each die is provided with holes. The buckling beam has an array of flexible wires positioned substantially perpendicular to the dies, each of the flexible wires crossing a corresponding hole in each of the top, offset and lower dies to allow each wire respectively contact a pad of the device under test. By shifting the center of the hole of the lower die relative to the center of the offset die, the tip of the wire exits from the lower die at an angle with respect to the plane formed by the pads of the device under test. The exit angle of the wire tip is controlled by the relative displacement of the offset die relative to the bottom die, such that the exit angle of the tip of the wire at the bottom die changes when the probe wire is under compression. By applying a reciprocating motion to the tip of the wire contacting the surface of the device under test, a scrubbing motion is achieved that lowers the resistance between the pad of the device under test. In this manner, the tip of the wire cleans the surface of the pads and prevents contaminants from adhering to the tip of the wire.

Self-scrub buckling beam probe

A cost-effective surface metallization structure of a TCA carrier is produced by using a high-grit conducting paste to fill TSM vias in the TSM of the TCA carrier. This concept can be applied to alumina substrates with refractory metal conductors or to LCGC substrates with more noble metal conductors.

Surface metallization structure for multiple chip test and burn-in

Disclosed is a multilayer ceramic substrate having an outer pad, for example an I/O pad, which is anchored to a middle pad of the multilayer ceramic substrate by a plurality of vias which in turn is anchored to an inner pad of the multilayer ceramic substrate by a second plurality of vias. The middle and outer pads and vias are made of high metal material, preferably 100% metal, so they won't adhere very well to the ceramic substrate. The inner pad is a composite metal/ceramic material which will bond very well to the ceramic substrate.

Multilayer ceramic substrate with anchored pad

Multilayer glass ceramic substrate electronic components having enhanced flexibility and strength are prepared using greensheets as a top and/or bottom layer, which greensheets are made from a glass-ceramic greensheet casting composition comprising crystallizable glass, a binder resin and a solvent system, and preferably a plasticizer. The top and/or bottom greensheets have a lower coefficient of thermal expansion (CTE) than the greensheets used to make the internal layers of the MLC and both greensheets are characterized by having, after sintering, a microstructure which is greater than 99% crystalline. A crystalline matrix forming material such as P,O,is preferably used in the composition. This type structure, in combination with the lower CTE, has been found to provide an MLC having enhanced strength and flexibility.

Method and materials for increasing the strength of crystalline ceramic

A semiconductor device having C-4 solder connections is joined to a chip carrier having pads suitable for receiving the C-4 solder connections. Sacrificial solder is formed on the chip carrier pads and then planarized to result in a good, planar surface profile for joining to the semiconductor device.

Method for assembling a chip carrier to a semiconductor device

Disclosed is a multilayer ceramic substrate having an outer pad, for example an I/O pad, which is anchored to an inner pad of the multilayer ceramic substrate by either a plurality of vias or one large via. The outer pad and vias are made of high metal material, preferably 100% metal, so they won't adhere very well to the ceramic substrate. The inner pad is a composite metal/ceramic material which will bond very well to the ceramic substrate.

A method for making multilayer ceramic substrates having substantially reduced planar shrinkage and distortion resulting from the firing or sintering process. Contact sheets are employed in the fabrication process on the surface of the multilayer ceramic substrate to be fired with the contact sheets being prepared from a composition containing a non-sinterable non-metallic inorganic material such as alumina having an average particle size approximately about 1 micron or less and an organic binder and preferably a plasticizer. In a preferred embodiment of the invention, the multilayer structure to be fired containing the contact sheet of the invention is provided with a beveled or chamfered edge at an angle of greater than about 60 degrees. A fabrication process employing only chamfering of the edge or the use of a contact sheet of the invention also provides improved multilayer ceramic substrate products. A further feature is a method to control the surface topography of surface metallization by adjusting the compressibility of the contact sheets during fabrication of the substrate.

Method for producing ceramic surfaces with easily removable contact

Disclosed is a multilayer ceramic substrate, and a method for forming same, which has an outer unsealed layer having a metallic via, an inner sealed layer having a composite via of metallic and ceramic materials and a further unsealed layer having a metallic via.

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Hyde Park, NY, United States of America

Scott Ira Langenthal