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Low melting temperature alloy structure for enchanced thermal interface

a low melting temperature alloy and thermal interface technology, applied in the direction of semiconductor/solid-state device details, lighting and heating apparatus, device performance challenges, etc., can solve the problems of more challenging interfaces to fabricate and maintain, problems associated, etc., to prevent leakage and oozing of alloy to surrounding areas, increase rigidity and compressibility, and enhance thermal interface

Inactive Publication Date: 2007-06-21
IBM CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

[0011] The shortcomings of the prior art are overcome and additional advantages are provided through the method and associated apparatus for providing an enhanced thermal interface. The to be formed interface is preferably between a heat sink and a chip and the operation of the chip provides the required heat dissipation needed to melt the alloy. The interface is formed by application of a structure or foil embedded in an alloy in solid form between two surfaces. Once heat is generated, such as through normal device operation, the alloy in the foil or structure melts forming the desired interface. The structure and foil, however, prevents the leaking and oozing of the alloy to surrounding areas. In alternate embodiments, the structure can have apertures such as a wire mesh to provide certain amount of rigidity and compressibility.

Problems solved by technology

Despite many of the advantages associated with this industry goal, providing many such components in a small footprint create device performance challenges.
One such challenge has to do with creating thermal interfaces that do not interfere with electrical conductivity and integrity of the device.
One of the more challenging interfaces to fabricate and maintain are thermal interfaces, such as those used in a computing environments for example between microprocessor chips and heat sinks.
Using thermal paste, however, has multiple problems associated with it.
For one assembly of devices with a thermal paste component is difficult as sufficient paste must be dispensed to completely cover the chip.
In addition, thermal paste is viscous and difficult to handle.
Nonetheless, the same features that make these joints attractive, can also lead to device integrity problems.
The problem is often caused due to poor wetting inherent in the low-melting temperature alloy interfaces between microprocessor chips and heat sinks.
The problem occurs due to the fact that when a layer of low-melting alloy is melted while it is squeezed between two surfaces, capillary action due to poor wetting, between the low-melting alloy and the chip and between the low-melting alloy and the heat sink, forces the molten alloy out of the interface.
With no molten alloy bridging the gap, the thermal performance of the cooling assembly suffers.
The molten alloy that is forced out of the interface, can also ooze and leak to other, and especially adjacent areas housing electrical components and potentially cause system degradation and failure.

Method used

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first embodiment

[0028]FIG. 2, is a cross sectional illustration of the present invention. In FIG. 2, a first embedded structure 200 is illustrated. The structure is preferably comprised of metal and has a form, such as being apertured, so that it can maintain a level of structural integrity and rigidity while being able to become embedded in an alloy 210 as will be discussed.

[0029] Despite some desired structural rigidity, in some instances it may be required for the interface and the structure 200 involved to maintain certain level of flexibility and compressibility. In this regard, it should be noted that the level of rigidity (or even compressibility) can be selectively achieved, maintained or increased by increasing or decreasing the level of surface apertures. In one embodiment of the present invention, the structure 200 has a mesh like structure to provide both rigidity and compressibility at the same time. In a preferred embodiment, the structure 200 is a wire mesh that it can easily contain...

second embodiment

[0036]FIG. 3 provides for an alternate embodiment of the present invention. In FIG. 3, a cross sectional illustration of a second embodiment for forming the interface 130 of FIG. 1 is provided using a foil 300. The foil 300 is embedded in a low-melting alloy 310 as depicted. As before the material of the foil 300 and the low melting alloy 310 have to be such that they do not readily react with one another.

[0037] In a preferred embodiment, before the foil 300 is embodied in the alloy 310, it is well cleaned by means known to those skilled in the art. To do so, in a preferred embodiment, the foil 300 is cleaned by sputter etching as before.

[0038] The thickness of the alloy embedded structure (300) can be selectively altered. In this case, the thickness can be a combination of thickness of the foil 300 or the applied alloy 310. The low melting alloy can also be applied by a variety of methods known to those skilled in the art as discussed before. For example, metal can be sputtered on...

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Abstract

A method and associated apparatus for providing an enhanced thermal interface. The interface is formed by application of a structure or foil embedded in an alloy in solid form between two surfaces. Once heat is applied from one or both surfaces, the alloy melts forming the desired interface.

Description

BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention generally relates to a method and apparatus for providing an enhanced thermal interface; and more particularly for a method and apparatus for providing an enhanced thermal interface used in semiconductor packaging of a computing environment. [0003] 2. Description of Background [0004] The evolution of semiconductor industry had led to an industry trend of continuously increasing the number of electronic components inside an electronic device. Compactness allows for selective fabrication of smaller and lighter devices that are more attractive to the consumer. In addition, compactness also allows many of the circuits to operate at higher frequencies and at higher speeds due to shorter electrical distances in these devices. Despite many of the advantages associated with this industry goal, providing many such components in a small footprint create device performance challenges. One such challenge h...

Claims

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Application Information

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IPC IPC(8): B21C37/00
CPCF28F13/00H01L23/3733H01L23/42Y10T428/12438H01L2924/0002F28F2013/006H01L2924/00
Inventor PACHECO, JAIRO D.SCHMIDT, ROGER R.SINGH, PRABJIT
Owner IBM CORP