Classifications

• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
  • H10W40/00—Arrangements for thermal protection or thermal control
  • H10W40/70—Fillings or auxiliary members in containers or in encapsulations for thermal protection or control
  • H10W40/73—Fillings or auxiliary members in containers or in encapsulations for thermal protection or control for cooling by change of state
• • H—ELECTRICITY
  • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
  • H10W—GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10
  • H10W40/00—Arrangements for thermal protection or thermal control
  • H10W40/40—Arrangements for thermal protection or thermal control involving heat exchange by flowing fluids
  • H10W40/43—Arrangements for thermal protection or thermal control involving heat exchange by flowing fluids by flowing gases, e.g. forced air cooling
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
  • F28D15/00—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies
  • F28D15/02—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes
  • F28D15/0233—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes the conduits having a particular shape, e.g. non-circular cross-section, annular
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28D—HEAT-EXCHANGE APPARATUS, NOT PROVIDED FOR IN ANOTHER SUBCLASS, IN WHICH THE HEAT-EXCHANGE MEDIA DO NOT COME INTO DIRECT CONTACT
  • F28D15/00—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies
  • F28D15/02—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes
  • F28D15/0266—Heat-exchange apparatus with the intermediate heat-transfer medium in closed tubes passing into or through the conduit walls ; Heat-exchange apparatus employing intermediate heat-transfer medium or bodies in which the medium condenses and evaporates, e.g. heat pipes with separate evaporating and condensing chambers connected by at least one conduit; Loop-type heat pipes; with multiple or common evaporating or condensing chambers
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
  • F28F1/00—Tubular elements; Assemblies of tubular elements
  • F28F1/10—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses
  • F28F1/12—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element
  • F28F1/24—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element and extending transversely
  • F28F1/32—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element and extending transversely the means having portions engaging further tubular elements
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F28—HEAT EXCHANGE IN GENERAL
  • F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
  • F28F3/00—Plate-like or laminated elements; Assemblies of plate-like or laminated elements
  • F28F3/02—Elements or assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with recesses, with corrugations

Definitions

• the technical field relates generally to cooling systems for electronics, and more particularly to a heat sink with vapor chambers and thermal dissipating fins.
• BACKGROUND Increasing levels of component power and power density from electronic devices such as integrated circuits and memory are creating an increased demand for thermal management solutions. For example, high-density blade servers have been in great demand in recent years due to their outstanding performance. This high density computing power, however, comes with very limited space in the server enclosure. Accordingly, high performance heat sinks are necessary for efficient cooling. The heat sinks in use today have reached their limit in dissipating the heat generated by power chips. A need for more efficient cooling exists to expand the thermal dissipation performance envelope. SUMMARY A heat sink is disclosed.
• the heat sink comprises a first vapor chamber section having an upper surface and a lower surface, a second vapor chamber section extending vertically from said upper surface of said first vapor chamber section, and heat- dissipating fins extending horizontally from said second vapor chamber section, wherein said lower surface is in thermal contact with a heat source and wherein said first and second vapor sections are connected to each other, forming a continuous vapor chamber space.
• a heat sink comprising: a hollow-centered base having a top surface and a bottom surface, wherein said bottom surface is in thermal contact with a heat source; two hollow-centered sidewalls located on two opposite sides of the base and extending upwardly from the top surface of the base; and one or more hollow-centered center columns located between the two sidewalls and extending upwardly from the top surface of the base, wherein the hollow centers of said base, said sidewalls and said one or more center columns are connected to each other forming a continuous vapor chamber space, and wherein said sidewalls and said center columns comprise fins for heat dissipation.
• a heat sink comprising: a planar-shaped first vapor chamber having a first surface and a second surface, wherein said first surface is opposite to said second surface and is in contact with a heat source; a second vapor chamber formed on said second surface, said second vapor chamber is connected to said first vapor chamber thus forming a continuous vapor chamber space; and a plurality of planar-shaped heat dissipating fins extending from said second vapor chamber.
• FIG. 1 is a cross-sectional view of a prior art heat sink.
• FIGS. 2A and 2B are schematic representations of two embodiments of a heat sink with innovative vapor chamber configuration
• FIG. 3 is a composite of schematic representations of a heat sink with free- standing center column configuration with (upper panel) or without (lower panel) fins;
• FIGS. 4A-4C are results of computational fluid dynamics (CFD) analysis of the heat sink configuration shown in FIG. 3;
• FIGS. 5A and 5B are results of CFD analysis of the airflow in the heat sink configuration shown in FIG. 3;
• FIG. 6 is a schematic representation of a heat sink with wall-like center column configuration;
• FIGS. 7A and 7B are results of CFD analysis of the heat sink configuration shown in FIG. 6;
• FIGS. 8A and 8B are results of CFD analysis of the airflow in the heat sink configuration shown in FIG. 6.
• relative terms such as “horizontal,” “vertical,” “up,” “down,” “top” and “bottom” as well as derivatives thereof (e.g., “horizontally,” “downwardly,” “upwardly,” etc.) should be construed to refer to the orientation as then described or as shown in the drawing figure under discussion. These relative terms are for convenience of description and normally are not intended to require a particular orientation. Terms including “inwardly” versus “outwardly,” “upwardly” versus “downwardly,” “longitudinal” versus “lateral” and the like are to be interpreted relative to one another or relative to an axis of elongation, or an axis or center of rotation, as appropriate.
• FIG. 1 is a conceptual illustration of a prior art heat sink with a vapor chamber.
• the vapor chamber is confined in a base plate having a lower surface and an upper surface.
• the lower surface is in thermal contact with a heat source and the upper surface comprises planar fins extending vertically from the upper surface for heat dissipation.
• FIG. 2A illustrates an embodiment of a heat sink with innovative vapor chamber configuration.
• Heat sink 10 comprises a vapor chamber base 20, vapor chamber sidewalls 30 and optionally one or more vapor chamber center columns 40.
• Each of the vapor chamber base 20, vapor chamber sidewalls 30 and vapor chamber center columns 40 is a hollow-centered structure that comprises a vapor chamber space enclosed by surrounding walls.
• the vapor chamber base 20, the sidewalls 30 and the center columns 40 are operatively connected to each other to form a continuous vapor chamber space.
• the base 20 contains a bottom surface 22 that is in thermal contact with a heat source, and a top surface 24 on which the sidewalls 30 and/or center columns 40 are formed.
• the base 20 is made of a material having a high thermal conductivity, such as a metal or alloy. In one embodiment, the base 20 is made of copper or aluminum.
• the base 20 is filled or partially filled with an evaporable working fluid, such as water.
• the sidewalls 30 are formed only on selected sides of the base 20 so as to maintain an unobstructed airflow between the sidewalls 30.
• two sidewalls 30 are formed on the opposite sides of the base 20. It should be noted that the sidewalls 30 do not need to be formed on the edges of the base 20. As shown in FIG. 2B, the two sidewalls 30 are formed at locations near the edges of the base 20.
• the center column 40 is formed between the sidewalls 30 to further facilitate heat dissipation from the base 20.
• the center column 40 is in the form of a free-standing column that serves as a heat pipe. Multiple free-standing center columns 40 may be used to facilitate heat transfer from the base 20 to fins 60.
• the center column 40 is in the form of a center wall that is parallel to the sidewalls 30 and extends from one side of the base 20 to the other side of the base 20. Multiple center walls may be formed between the sidewalls 30 to facilitate heat transfer from the base 20 to fins 60.
• the sidewalls 30 and center columns 40 are made of a material having a high thermal conductivity, such as a metal or alloy. In one embodiment, the sidewalls 30 and center columns 40 made of copper or aluminum.
• the vapor chamber base 20, sidewalls 30 and center columns 40 are filled with a porous material 50.
• the porous material 50 has a porosity that allows vapor transport from the base 20, where evaporation takes place, to sidewalls 30 and center columns 40, where condensation of the vapor takes place.
• the capillary forces created by the porous material also facilitate the return of condensed working fluid to the base 20.
• the porous material 50 include, but are not limited to, sintered powder wick which can be attached to the vapor chamber base 20, sidewalls 30 and/or center columns 40 by solder.
• the sintered powder may be selected from any of the materials having high thermal conductivity and that are suitable for fabrication into porous structures, e.g., carbon, tungsten, copper, aluminum, magnesium, nickel, gold, silver, aluminum oxide, beryllium oxide, or the like, and may comprise either substantially spherical, arbitrary or regular polygonal, or filament-shaped particles of varying cross-sectional shape.
• the porous material 50 comprises sintered copper wick.
• Other wick materials such as aluminum-silicon-carbide or copper-silicon-carbide may be used with equal effect.
• the sidewalls 30 and/or center columns 40 further comprise a plurality of stacked fins 60 for efficient heat dissipation.
• the fins 60 are attached in horizontal arrangement to the sidewalls 30 and center columns 40.
• Each fin 60 has a planar-shaped main body having a top surface 62 and a bottom surface 64 opposite to the top surface 62.
• the top surface 62 of one fin and the bottom surface 64 of the neighboring fin are parallel to each other.
• the distance (d) between the two neighboring fins 60 may be determined experimentally to allow for efficient cooling of the fins 60 by airflow. In one embodiment, the distance (d) is in the range of 0.5-5 mm.
• the fins 60 are typically made of a material having high thermal conductivity, such as a metal or an alloy. In one embodiment, the fins 60 are made of aluminum.
• the heat sink 10 may be used to cool a heat-generating device which may be an electronic component such as, but not limited to, an integrated circuit, a memory module, a Micro-Electro-Mechanical System (MEMS), a sensor, a resister, or a capacitor.
• the heat sink 10 may be positioned directly on the electronic component, or on a thermal solution including, but not limited to, a heat pipe, a heat spreader, a heater block, and a thermal transfer plate.
• a fan may be complementarily positioned to accelerate airflow between fins 60 and increase the rate of heat dissipation.
• the exact complementary positioning is application dependent, and may be affected by a number of factors, including but not limited to, the amount of heat to be removed, the volume and velocity of the airflow, and so forth.
• the optimal complementary positioning for a particular application of flow provider and flow modifier may be determined empirically.
• FIGS. 3-5B show results of a CFD analysis of a heat sink with free-standing center column configuration.
• the heat sink device contains six freestanding center columns 40 that are attached to the vapor chamber base 20.
• the freestanding center columns 40 serve as heat pipes to transfer heat from the base 20 to fins 60. Heat dissipation was achieved by eighteen aluminum plate fins 60 attached to the center columns 40.
• the fins have a thickness of 0.5 mm, a surface area of 80 x 85 mm, and a fin-to-fin gap of 1.1 mm.
• FIGS. 4A-4C show heat distribution on the center columns 40 (FIG. 4A) and fins 60 (FIG. 4B) and the base plate 20 (FIG. 4C).
• FIGS. 5 A and 5B show the airflow generated by fins 60.
• Example 2 CFD analysis of heat sink with wall-like center column configuration
• FIGS. 6A-8B show results of a CFD analysis of a heat sink with wall-like center column configuration.
• the heat sink device contains a base vapor chamber, two sidewalls and a wall-like center column.
• the sidewalls 30 and the center column 40 are operatively connected to base 20 and form a continuous vapor chamber space.
• Heat dissipation was achieved by eighteen aluminum plate fins attached to the center columns.
• the fins have a thickness of 0.5 mm, a surface area of 80 x 85 mm, and a fin-to-fin gap of 1.1 mm.
• FIGS. 7A-7B show heat distribution on the base plate 20
• FIGS. 7A and 7B show the airflow generated by fins 60.
• the heat sink with wall- like center column configuration was able to achieve a H 0 C improvement over the heat sink with free-standing center column configuration, i.e., having a source temperature of 45°C (FIG. 7B) vs. 56°C (FIG. 4C).

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• Cooling Or The Like Of Semiconductors Or Solid State Devices (AREA)
• Cooling Or The Like Of Electrical Apparatus (AREA)

Applications Claiming Priority (1)

Publications (2)

Family

ID=41016382

Family Applications (1)

Country Status (4)

Families Citing this family (36)

Family Cites Families (12)

• 2008
  • 2008-02-27 CN CN200880127575.2A patent/CN101960938A/zh active Pending
  • 2008-02-27 WO PCT/US2008/055126 patent/WO2009108192A1/en not_active Ceased
  • 2008-02-27 US US12/919,260 patent/US20110000649A1/en not_active Abandoned
  • 2008-02-27 EP EP08730843A patent/EP2248406A4/de not_active Withdrawn

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