WO2015012792A1

WO2015012792A1 - Screw plug adjustable heat sinks and methods of fabricating the same

Info

Publication number: WO2015012792A1
Application number: PCT/US2013/051484
Authority: WO
Inventors: Michael Parker
Original assignee: Ge Intelligent Platforms, Inc.
Priority date: 2013-07-22
Filing date: 2013-07-22
Publication date: 2015-01-29

Abstract

An adjustable heat sink assembly may include a heat sink body including a first surface and an opposing second surface. The heat sink body defines a threaded hole that extends from the first surface to the opposing second surface. A plug is disposed within the threaded hole. The plug includes an external thread that is configured to mate with the threaded hole. Solder is disposed within the threaded hole so as to be between the heat sink body and the plug. The solder fuses the plug to the heat sink body.

Description

SCREW PLUG ADJUSTABLE HEAT SINKS AND METHODS OF

FABRICATING THE SAME

BACKGROUND

Field

[0001] The present disclosure relates to passive heat exchangers that cool devices in electronic systems by dissipating the excess heat into the surrounding air.

Description of Related Art

[0002] A heat sink is one type of passive heat exchanger that is used to cool heat- generating devices in electronic systems. Generally, a heat sink should have an adequate level of thermal contact with a heat-generating device in order to provide the proper cooling. However, heat-generating devices vary in height, which results in air gaps and complicates efforts to ensure an adequate level of thermal contact with a heat sink. To address such height variances, heat sinks are custom-made to provide the requisite fit. Unfortunately, having heat sinks custom-made requires additional time and results in manufacturing delays. While a surplus of custom-made heat sinks of an array of different sizes may be maintained in anticipation of future use, such maintenance is relatively burdensome. To avoid having to order custom-made heat sinks, thermal adhesive or thermal grease may be used to fill the air gap between the heat sink and the heat-generating device, but the resulting thermal contact is less than desired due to the lower conductivity of the thermal adhesive or thermal grease.

BRIEF DESCRIPTION OF EXAMPLE EMBODIMENTS [0003] An adjustable heat sink assembly may include a heat sink body including a first surface and an opposing second surface, the heat sink body defining a threaded hole that extends from the first surface to the opposing second surface; a plug disposed within the threaded hole, the plug including an external thread that is configured to mate with the threaded hole; and solder disposed within the threaded hole so as to be between the heat sink body and the plug, the solder fusing the plug to the heat sink body.

[0004] A method of fabricating an adjustable heat sink assembly may include screwing a plug into a threaded hole defined by a heat sink body, the plug including an external thread that is configured to mate with the threaded hole; providing solder to a region of the heat sink body that is adjacent to a sidewall of the threaded hole; and applying heat to melt the solder such that the solder penetrates into an interface between the plug and the heat sink body, the solder fusing the plug to the heat sink body.

BRIEF DESCRIPTION OF THE DRAWINGS

[0005] The various features and advantages of the non-limiting embodiments herein may become more apparent upon review of the detailed description in conjunction with the accompanying drawings. The accompanying drawings are merely provided for illustrative purposes and should not be interpreted to limit the scope of the claims. The accompanying drawings are not to be considered as drawn to scale unless explicitly noted. For purposes of clarity, various dimensions of the drawings may have been exaggerated. [0006] FIG. 1 is a perspective view of an adjustable heat sink assembly according to an example embodiment.

[0007] FIG. 2 is a perspective view of another adjustable heat sink assembly according to an example embodiment.

[0008] FIG. 3 is a perspective view of another adjustable heat sink assembly according to an example embodiment.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

[0009] It should be understood that when an element or layer is referred to as being "on," "connected to," "coupled to," or "covering" another element or layer, it may be directly on, connected to, coupled to, or covering the other element or layer or intervening elements or layers may be present. In contrast, when an element is referred to as being "directly on," "directly connected to," or "directly coupled to" another element or layer, there are no intervening elements or layers present. Like numbers refer to like elements throughout the specification. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

[0010] It should be understood that, although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers, and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer, or section from another region, layer, or section. Thus, a first element, component, region, layer, or section discussed below could be termed a second element, component, region, layer, or section without departing from the teachings of example embodiments.

[0011] Spatially relative terms (e.g., "beneath," "below," "lower," "above," "upper," and the like) may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It should be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the term "below" may encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[0012] The terminology used herein is for the purpose of describing various embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "includes," "including," "comprises," and/or "comprising," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

[0013] Example embodiments are described herein with reference to cross- sectional illustrations that are schematic illustrations of idealized embodiments (and intermediate structures) of example embodiments. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, example embodiments should not be construed as limited to the shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. For example, an implanted region illustrated as a rectangle will, typically, have rounded or curved features and/or a gradient of implant concentration at its edges rather than a binary change from implanted to non-implanted region. Likewise, a buried region formed by implantation may result in some implantation in the region between the buried region and the surface through which the implantation takes place. Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the actual shape of a region of a device and are not intended to limit the scope of example embodiments.

[0014] Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which example embodiments belong. It will be further understood that terms, including those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.

[0015] FIG. 1 is a perspective view of an adjustable heat sink assembly according to an example embodiment. Referring to FIG. 1, the adjustable heat sink assembly 100 includes a heat sink body 102 and a plug 110. The heat sink body 102 includes a first surface 104 and an opposing second surface 106. The heat sink body 102 defines a threaded hole 108 that extends from the first surface 104 to the opposing second surface 106. The plug 110 is disposed within the threaded hole 108. The plug 110 includes an external thread that is configured to mate with the threaded hole 108. Solder 112 is disposed within the threaded hole 108 so as to be between the heat sink body 102 and the plug 110. The solder 112 fuses the plug 110 to the heat sink body 102. Those of ordinary skill in the art will readily appreciate that "solder" is a fusible metal alloy that is used to join metal workpieces, wherein the solder has a melting point below that of the workpieces.

[0016] The heat sink body 102 is formed of a thermally conductive material. For example, the heat sink body 102 may be formed of at least one of aluminum and copper, although other materials having adequate heat transfer properties may be used. In particular, a portion of the heat sink body 102 may be formed of a less conductive material (e.g., aluminum), while another portion may be formed of a more conductive material (e.g., copper). For instance, the heat sink body 102 may include a first section and a second section, wherein the first section is more conductive than the second section. The first section may be between the plug 110 and the second section. In a non- limiting embodiment, the first section may surround the plug 110, and the first section may be sandwiched between two second sections. The first section may be formed of copper, and the second section may be formed of aluminum. Those of ordinary skill in the art may refer to such a copper first section as a "copper highway." However, it should be understood that other conductive metals may be used to form the first and second sections.

[0017] The plug 110 is formed of a thermally conductive material. For example, the plug 110 may be formed of at least one of aluminum and copper, although other materials having adequate heat transfer properties may be used. The plug may also be nickel plated. Additionally, the plug 110 has a shape that corresponds to that of the hole 108. Although the drawings show the plug 110 and hole 108 as being square- shaped, it should be understood that other shapes may be used. For example, the plug 110 and hole 108 may be round-shaped, oval-shaped, triangular-shaped, rectangular- shaped, diamond-shaped, trapezoidal-shaped, pentagonal-shaped, hexagonal-shaped, etc., although example embodiments are not limited thereto.

[0018] The plug 110 includes a top surface and a bottom surface. The top surface of the plug 110 includes inner markings 114 along a periphery of the plug 110. The first surface of the heat sink body 102 includes outer markings 116 around the threaded hole 108. The inner markings 114 are configured to align with the outer markings 116 upon rotation of the plug 110. Although the drawings only show two inner markings 114, it should be understood that a different number may be used to indicate the depth of insertion of the plug 110 based on the alignment of the inner markings 114 with the outer markings 116. The outer markings 116 may be divided into 10 degree increments, although different increments may be used.

[0019] The solder 112 has a melting point of less than 150 degrees Celsius. As a result, damage to an electronic system will be avoided during the soldering process. In particular, the solder 112 may have a melting point ranging from 110-140 degrees Celsius. The solder 112 may be a eutectic alloy. Those of ordinarily skill in art will appreciate that a "eutectic alloy" is an alloy that melts at a single temperature that is lower than any other composition made up of the same elements. However, it should be understood that near-eutectic and non-eutectic alloys may also be used if the melting point(s) are acceptable. [0020] The solder 112 may be a binary alloy including Group 13-15 metals. In a non- limiting embodiment, the solder 112 may include indium and tin. For example, the solder 112 may include 52 percent indium by weight and 48 percent tin by weight. In another instance, the solder 112 may include bismuth. However, it should be understood that other metals that provide a solder with a relatively low melting point may also be used. Desirable melting points include those that are higher than the expected operating temperature of the electronic system (so as to remain stable) but lower than a temperature that would cause damage to the electronic system during soldering.

[0021] FIG. 2 is a perspective view of another adjustable heat sink assembly according to an example embodiment. Referring to FIG. 2, the adjustable heat sink assembly may include a plurality of plugs 210a, 210b, 210c, 210d, 210e, and 21 Of. For instance, plugs 210a and 210e may be formed of copper, while plugs 210b, 210cm 210d, and 21 Of may be formed of aluminum, although example embodiments are not limited thereto.

[0022] FIG. 3 is a perspective view of another adjustable heat sink assembly according to an example embodiment. Referring to FIG. 3, the first section 318 of the heat sink body 102 may be formed of copper. The second section 320 of the heat sink body 102 may be formed of aluminum.

[0023] A method of fabricating an adjustable heat sink assembly may include screwing a plug into a threaded hole defined by a heat sink body, the plug including an external thread that is configured to mate with the threaded hole; providing solder to a region of the heat sink body that is adjacent to a sidewall of the threaded hole; and applying heat to melt the solder such that the solder penetrates into an interface between the plug and the heat sink body, the solder fusing the plug to the heat sink body. The method may further include measuring a height of a component on a circuit board to determine a desired position of the plug within the threaded hole prior to the screwing step; and calculating a number of rotations that will be needed during the screwing step to dispose the plug in the desired position. The screwing my include engaging in the number of rotations determined from the calculating step. The method may further include mounting the heat sink body onto a circuit board such that the threaded hole is aligned with a component on the circuit board prior to the screwing step. The screwing may include rotating the plug until the plug makes thermal contact with the component on the circuit board.

[0024] According to the non-limiting embodiments of the present disclosure, a customized heat sink assembly with a desirable amount of thermal contact with a heat-generating device may be provided in a relatively short period of time.

[0025] While a number of example embodiments have been disclosed herein, it should be understood that other variations may be possible. Such variations are not to be regarded as a departure from the spirit and scope of the present disclosure, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.

Claims

1. An adjustable heat sink assembly comprising:

a heat sink body including a first surface and an opposing second surface, the heat sink body defining a threaded hole that extends from the first surface to the opposing second surface;

a plug disposed within the threaded hole, the plug including an external thread that is configured to mate with the threaded hole; and

solder disposed within the threaded hole so as to be between the heat sink body and the plug, the solder fusing the plug to the heat sink body.

2. The adjustable heat sink assembly of claim 1, wherein the heat sink body is formed of at least one of aluminum and copper.

3. The adjustable heat sink assembly of claim 1, wherein the heat sink body includes a first section and a second section, the first section being between the plug and the second section, the first section being formed of copper, the second section being formed of aluminum.

4. The adjustable heat sink assembly of claim 1, wherein the plug is formed of at least one of aluminum and copper.

5. The adjustable heat sink assembly of claim 1, wherein the plug is nickel plated.

6. The adjustable heat sink assembly of claim 1, wherein the plug includes a top surface and a bottom surface, the top surface of the plug including inner markings along a periphery of the plug, the first surface of the heat sink body including outer markings around the threaded hole, the inner markings configured to align with the outer markings upon rotation of the plug.

7. The adjustable heat sink assembly of claim 1, wherein the solder has a melting point of less than 150 degrees Celsius.

8. The adjustable heat sink assembly of claim 1, wherein the solder has a melting point ranging from 110-140 degrees Celsius.

9. The adjustable heat sink assembly of claim 1, wherein the solder is a eutectic alloy.

10. The adjustable heat sink assembly of claim 1, wherein the solder is a binary alloy including Group 13-15 metals.

11. The adjustable heat sink assembly of claim 1, wherein the solder includes indium and tin.

12. The adjustable heat sink assembly of claim 1, wherein the solder includes 52 percent indium by weight and 48 percent tin by weight.

13. The adjustable heat sink assembly of claim 1, wherein the solder includes bismuth.

14. A method of fabricating an adjustable heat sink assembly, comprising: screwing a plug into a threaded hole defined by a heat sink body, the plug including an external thread that is configured to mate with the threaded hole;

providing solder to a region of the heat sink body that is adjacent to a sidewall of the threaded hole; and

applying heat to melt the solder such that the solder penetrates into an interface between the plug and the heat sink body, the solder fusing the plug to the heat sink body.

15. The method of fabricating an adjustable heat sink assembly of claim 14, further comprising:

measuring a height of a component on a circuit board to determine a desired position of the plug within the threaded hole prior to the screwing step; and

calculating a number of rotations that will be needed during the screwing step to dispose the plug in the desired position,

wherein the screwing includes engaging in the number of rotations determined from the calculating step.

16. The method of fabricating an adjustable heat sink assembly of claim 14, further comprising: mounting the heat sink body onto a circuit board such that the threaded hole is aligned with a component on the circuit board prior to the screwing step,

wherein the screwing includes rotating the plug until the plug makes thermal contact with the component on the circuit board.