International Business Machines Corporation

Horatio Quinones

Eugene R Atwood

Joseph Angelo Benenati

Giulio DiGiacomo

Karl Joseph Puttlitz

Eric J Kastberg

James J Dankelman

Keith F Beckham

David Clifford Long

David Carroll Challener

Krishna Seshan

James Marc Leas

Peter Jeffrey Brofman

Arunava Gupta

Charles L Reynolds

Wai Mon Ma

Chon Cheong Lei

Ernest N Levine

Karl J Puttlitz, Sr

Joseph M Harvilchuck

James R Lloyd

Lewis D Lipschutz

Ellyn M Ingalls

Timothy W Donahue

Morris Shatzkes

Kathleen M McGuire

Anne E Kolman

Thermal enhancement approach using solder compositions in the liquid state

Solder compositions are introduced to interface between an IC chip and its associated heat exchanger cover. The solder compositions have a solidus-liquidus temperature range that encompasses the IC chip operational temperature range. The solder composition has the desired property of absorbing and rejecting heat energy by changing state or phase with each temperature rise and decline that result from temperature fluctuations associated with the thermal cycles of the integrated circuit chips. A path for high thermal conduction (low thermal resistance) from the IC chip to the heat exchanger to the ambient air is provided by an electronic module cover, configured as a cap with a heat exchanger formed or attached as a single construction, and made of the same material as the substrate, or made with materials of compatible thermal coefficients of expansion to mitigate the effects of vertical displacement during thermal cycling. The cap-heat exchanger cover is constructed to be compliant, and to contact both the IC chip and substrate.

A heat sink in a heat transfer relationship with a substrate such as an integrated chip, chip carrier, or other electronic package. The heat sink is connected to a frame which is connected to a printed circuit board or other suitable support on which the substrate is positioned. The heat sink, which extends through an aperture in the frame is coupled to a surface of the substrate. The heat sink is mechanically decoupled from the substrate. Large heat sinks may be thermally connected to surface mount substrates mounted using technologies such as ceramic ball or column grid arrays, plastic ball or column grid arrays, or solder balls or columns. The heat sink is attached coaxially through the aperture to the substrate. After assembly and lead/tin or other metallic surface mount interconnects are relaxed such that the substrate and is completely supported by the frame and the heat sink imparts zero or nearly zero downward force. Because the heat sink moves freely within the aperture during assembly, the heat sink package is useful for a variety of different substrates. Preferably, the frame is a plate and a plurality of studs. The plate material are selected to match the thermal expansion of the underlying support, and the stud material matched the thermal expansion of the substrate. Thus, the frame construction allows matching expansion and contraction of the assembly to the underlying substrate and support.

Zero force heat sink

A non-destructive method for identifying off-composition solder columns of for example, a ceramic column grid array. The method is performed at the ceramic module level prior to card assembly to avoid costly loss or rework post card assembly. The assembly of solder columns on a substrate is heated to a temperature below the melting temperature of pure-composition solder and above the temperature of attachment of a solder column to an organic board. Heating the assembly produces visually detectable changes characteristic of off-composition solder which are used for identifying which solder columns are composed of off-composition solder.

Non-destructive low melt test for off-composition solder

A heat sink is placed in a heat transfer relationship with a substrate such as an integrated chip, chip carrier, or other electronic package, without imparting stressful forces to the substrate by connecting the heat sink to a frame which is connected to a support such as a printed circuit board or other suitable carrier on which the substrate is positioned. The heat sink extends through an aperture in the frame and is in heat transfer relationship with a surface of the substrate; however, it is mechanically decoupled from the substrate. The invention has particular application in thermally connecting large heat sinks to substrates that are surface mounted on the support using technologies such as ceramic ball or column grid arrays, plastic ball or column grid arrays, or solder balls or columns. In order to provide intimate contact between the substrate and the heat sink, the heat sink must be depressed coaxially through the aperture of the frame against a surface of the substrate and then secured by, for example, gluing while in contact with the surface. However, this downward force imparted by the heat sink is quickly reduced via relaxation of the lead/tin or other metallic elements of the surface mount. A heat sink in a heat transfer relationship with a substrate such as an integrated chip, chip carrier, or other electronic package. The heat sink is connected to a frame which is connected to a printed circuit board or other suitable support on which the substrate is positioned. The heat sink, which extends through an aperture in the frame is coupled to a surface of the substrate. The heat sink is mechanically decoupled from the substrate. Large heat sinks may be thermally connected to surface mount substrates mounted using technologies such as ceramic ball or column grid arrays, plastic ball or column grid arrays, or solder balls or columns. The heat sink is attached coaxially through the aperture to the substrate. After assembly and lead/tin or other metallic surface mount interconnects are relaxed such that the substrate and is completely supported by the frame and the heat sink imparts zero or nearly zero downward force. Because the heat sink moves freely within the aperture during assembly, the heat sink package is useful for a variety of different substrates. Preferably, the frame is a plate and a plurality of studs. The plate material are selected to match the thermal expansion of the underlying support, and the stud material matches the thermal expansion of the substrate. Thus the frame construction allows matching expansion and contraction of the assembly to the underlying substrate and support.

A method for causing an open circuit in an electrical conductor is provided, including the steps of: conducting a direct current through the conductor; and applying heat at a selected location on the conductor whereat it is desired to cause the open circuit of the conductor.

Method and apparatus for causing an open circuit in a conductive line

In accordance with the present invention, we provide a new method for relieving stresses in the device-substrate interconnection structure which greatly enhances the resistance of the interconnection solder bonds to fatigue failure. In accordance with the aforementioned object of the process of our invention for forming improved solder interconnections between integrated circuit semiconductor devices and the supporting substrate, the process includes the step of joining the device I/O pads to the corresponding I/O pads of the substrate by positioning the device over the substrate with solder material selectively positioned between the respective I/O pads, heating the assembly to at least the melting point of the solder material, and cooling to solidify the solder. Subsequently, the resultant device-substrate is annealed by heating to an annealing temperature in the range of 115.degree. to 135.degree. C. and maintaining this temperature for a time in excess of 2 days.

Process for forming improved solder connections for semiconductor

An improved solder interconnection for forming I/O connections between an integrated semiconductor device and a support substrate having a plurality of solder connections arranged in an area array joining a set of I/O's on a flat surface of the semiconductor device to a corresponding set of solder wettable pads on a substrate, the improvement being a band of dielectric organic material disposed between and bonded to the device and substrate embedding at least an outer row of solder connections leaving the center inner solder connections and the adjacent top and bottom surfaces free of dielectric material.

Solder interconnection structure for joining semiconductor devices to

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Wappingers Falls, NY, United States of America

Horatio Quinones