TWI246878B - Phase change thermal conductive plate and heat dissipating device having same - Google Patents

Abstract

A phase change thermal interface plate includes a phase change thermal interface material having a polymer matrix and fillers dispersed therein. The fillers include carbon nanocapsules. A heat dissipating device having the same phase change thermal interface plate is provided accordingly.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat conducting structure, and more particularly to a phase change thermally conductive sheet for conducting heat generated when an electronic component such as a chip or the like is operated, and using the same A heat sink for a phase change thermal pad. [Prior Art]

When electronic components such as CPU microprocessors move toward highly integrated components and high computational speeds, the thermal energy generated per unit area is relatively increased. In order to quickly dissipate this dense heat to the environment and effectively reduce the surface temperature of the electronic components, a heat-dissipating component having a large area is usually attached to the surface of the heat-generating electronic component to increase the overall heat-dissipating area and improve the heat-dissipating effect. Since the surface of the heat dissipating component in contact with the heat generating electronic component is not a completely flat surface, the two cannot be in close contact, thereby forming an air gap between the contact faces. Air is a medium with poor thermal conductivity, which causes an increase in the thermal interface resistance of the equivalent interface, which does not effectively dissipate heat. To reduce the thermal resistance of the thermal interface, some thermal conductivity thermal interface material can be applied between the two contact surfaces to fill the air gap.

In general, thermal interface materials can be classified into thermal grease, thermal grease and phase change thermal adhesive. The thermal resistance coefficient is proportional to the thickness of the heat transfer medium and inversely proportional to the thermal conductivity of the heat transfer medium. At present, a wide range of heat-dissipating pastes and heat-dissipating glues are usually applied in a coating manner on the surface of the heat-dissipating module in contact with the electronic components, so that the heat-dissipating effect is remarkably improved. However, since the heat-dissipating paste (or heat-dissipating glue) is likely to cause uneven coating or unevenness during coating, when it is bonded to the surface of the heat-generating electronic component, a bubble-like cavity is generated inside the heat-dissipating paste (or heat-dissipating glue). . This void causes the heat generated by the heat-generating electronic components to fail.

Page 4 1246878 V. Description of the invention (2) Conducted quickly or completely to the heat dissipation module, thus affecting the heat dissipation effect.

Phase change thermal pastes are typically used for high efficiency or fast computing electronic components. It is solid at room temperature and undergoes a phase change (solid-state to liquid) by heating, thereby filling the gap between the heat-dissipating module and the heat-generating electronic component without generating bubbles. However, the phase change thermal paste used in the phase change thermal conductive sheet which is generally commercially available has a thermal resistance coefficient which is higher than that of the thermal grease, resulting in a decrease in heat dissipation efficiency. The industry has used particles of thermal conductive materials such as silver and copper to fill the phase change thermal conductive adhesive to improve its thermal conductivity. However, due to the thermal conductivity of the filling material itself, the heat dissipation efficiency of the heat dissipation structure using the phase change thermal adhesive remains to be determined. improve. In view of the above, it is necessary to provide a phase change thermally conductive sheet having good thermal conductivity and a heat sink and structure using the phase change thermally conductive sheet. [Contents] In order to solve the problem of low thermal conductivity of a conventional phase change thermally conductive sheet, it is an object of the present invention to provide a phase change thermally conductive sheet having good thermal conductivity. Another object of the present invention is to provide a heat sink using the above-described phase change thermally conductive sheet.

To achieve the object of the invention, the present invention provides a phase change thermally conductive sheet comprising a phase change thermally conductive material. The phase change thermally conductive material comprises a matrix and a plurality of filler particles dispersed in the matrix. Wherein the filler particles comprise nanocarbon spheres. The nanocarbon carbon spheres have a diameter ranging from 5 to 50 nm. To achieve another object of the present invention, the present invention provides a heat sink comprising: a heat dissipating component including a surface; and a heat dissipating component

Page 5 1246878 V. The phase change thermally conductive sheet of the surface of the invention (3) comprises a phase change thermal conductive material. The phase change thermally conductive material comprises a matrix and a plurality of filler particles dispersed in the matrix. Wherein the filler particles comprise nanocarbon spheres.

Compared with the prior art, the present invention incorporates a carbon carbon sphere into a phase change thermally conductive material, and utilizes a high thermal conductivity of the nanocarbon sphere to improve the thermal conductivity of the phase change heat guide. Moreover, since the nanocarbon sphere has a nanometer size, it can effectively fill the gap between the contact surface of the heat dissipation module and the heat generating electronic component, thereby reducing the thermal resistance of the contact between the heat dissipation module and the heat generating electronic component. Therefore, the heat dissipation efficiency of the heat sink and the structure using the phase change thermally conductive sheet is improved. [Embodiment] Hereinafter, the present invention will be further described in detail with reference to the accompanying drawings. Referring to the first figure, the heat sink 5 of the present invention comprises a heat sink 51 and a phase change heat conducting sheet 53. The heat sink 51 includes a surface 510 to which the phase change heat conducting sheet 53 is attached.

In this embodiment, the heat sink 51 includes a substrate 51 and a plurality of heat sink fins 51. There is a certain interval between adjacent heat dissipation fins 51. The heat radiating fin 512 may be fixed to the substrate 51 1 by dry joint or formed integrally with the substrate 51 1 . The substrate 5 1 1 and the heat sink fins 5 1 2 are generally made of a metal material having good thermal conductivity. The surface 5 10 is a side surface of the substrate 5 1 1 facing away from the heat dissipation fins 5 1 2 . The present invention provides a phase change thermally conductive sheet 5 3 which mainly comprises a phase change thermally conductive material. The phase change thermally conductive material comprises a matrix and a plurality of filler particles dispersed in the matrix. Wherein, the filler particles comprise nano carbon spheres.

Page 6 1246878 V. Description of Invention (4) " The optimum range of solid-liquid phase change temperature of the phase change thermal conductive material is 5〇 - ^. It generally consists of a matrix and a plurality of filled particles. The substrate is usually a substrate which may be selected from the group consisting of paraffin resins, enamel resins, acrylic resins, epoxy resins, urethane rubbers, polyethers and acrylates. In addition, the substrate may also be composed directly of a non-polymeric material which is easy to dazzle, including strontium, In/Sn,

In/Ag, Sn/Ag, Sr^In/Ag, Sn/Ag/Cu, Sn/Bi, In/Sn/Bi 彳in an. The substrate is preferably selected to have a lower melting temperature, but is solid at room temperature = material. The substrate may further be added with a crosslinking agent such as a multifunctional amine, a phenol resin, a polyhydroxy compound, a peroxide or a nitride, which may be selected according to different matrix materials. The filler particles are dispersed inside the substrate and composed of particles of a material having good thermal conductivity. The filler particles of the present invention include nanocarbon spheres. The nanocarbon is a polyhedral carbon crucible composed of a layer of graphite formed by spheres in a sphere, and may have a spherical, ellipsoidal or capsule structure. The optimal diameter of the nanocarbon sphere is 5 to 5 nanometers, and the average diameter is 30 nanometers. It can be a hollow nanocarbon sphere and a filled metal carbon sphere. The high thermal conductivity metal filled in the filled metal carbon sphere can be selected from the following materials, such as metallic copper, metallic silver, and the like. In addition, it can be selected from Moonstone bismuth copper, and its composition can be: copper (Cu) 96.5%, tin (Sn) 3.5~ 4.5%, lin (ρ) 〇 · 〇 3 ~ 0 · 35%, wrong (Pb) <(L5%, iron (Fe) < 0.1%, zinc (Ζη) < 0·5%. The filler particles may further include other poorly soluble particles and fusible particles. Among them, the refractory particles may be Selected from Ni, Cu, Ag, Sn, A1, A 12 03, BN, A 1 N and ceramic materials; the fusible particles may be selected from in,

In/Sn, In/Ag, Sn/Ag, Sn/In/Ag, Sn/Ag/Cu, Sn/Bi,

1246878 V. Description of invention (5)

In/Sn/Bi and In/Zn 〇 can form a phase change thermal conductive sheet containing nano carbon spheres by the following steps: heating the phase change thermal conductive material to its phase change point and then adding a nano carbon sphere in the molten state It is evenly dispersed in the matrix of the phase change heat-conducting material by shaking, stirring, etc., and then placed at room temperature to become a solid.

Alternatively, the phase change thermally conductive sheet 53 may further comprise an aluminum sheet or an insulator material as a carrier for carrying the phase change thermally conductive material. Wherein, the phase change heat conductive material may be distributed on opposite side surfaces of the carrier. The phase change thermally conductive sheet 53 may further include a protective layer that is placed away from the surface of the heat dissipating member for waterproofing and antifouling of its unused surface. The phase change heat conducting sheet 53 is attached to the heat sink 51, and can be liquefied by heating the phase change heat conductive material (for example, heating the phase change temperature of the heat sink 51 to the phase change heat conductive material) and uniformly distributed on the surface of the heat sink 5 1 10, and then reduced to room temperature to cure. Of course, the phase change thermally conductive material may be distributed over the entire area of the surface 5 1 0 or may be selectively distributed over a portion thereof.

Please refer to the second figure, which is a schematic diagram of the heat dissipation device 5 provided by the present invention directly applied to heat dissipation of electronic components. The heat sink 5 of the present invention is placed on the heat generating electronic component 6, and the phase change heat conducting sheet 53 of the heat sink 5 contacting the bottom surface is in contact with the heat generating electronic component 6, and the heat sink 5 is fixed to the heat generating electron by the heat sink fastening device 7. Component 6. Among them, the heat-generating electronic component 6 can be a chip package, which generates high-density heat during operation. The heat sink 5 may further include a fan to improve the heat dissipation effect. It can be understood that the heat sink used in the embodiment is only used to say

Page 8 1246878 V. INSTRUCTION DESCRIPTION (6) In the present invention, other heat sinks of the prior art can also be applied to the present invention. In addition, the heat pipe and the heat conducting plate can be selected as the heat dissipating component of the heat dissipating device, and are not limited to the heat sink formed by the heat dissipating fin. Of course, it is also possible to connect the two by heating the phase change thermally conductive sheet separately to its solid liquid phase transition temperature and between the heat generating electronic component and the heat dissipating component.

The invention adds nano carbon spheres to the phase change heat conductive material, and utilizes the high thermal conductivity of the nano carbon sphere to improve the thermal conductivity of the phase change thermal conductive sheet. Moreover, since the nanocarbon sphere has a nanometer size, it can effectively fill the gap between the contact surface of the heat dissipation module and the heat generating electronic component, thereby reducing the contact thermal resistance between the heat dissipation module and the heat generating electronic component. Therefore, the heat dissipation efficiency of the heat sink and the structure using the phase change heat conduction sheet is improved. In summary, the present invention has indeed met the requirements of the invention patent, and has filed a patent application according to law. However, the above description is only a preferred embodiment of the present invention, and those skilled in the art of the present invention, etc., should be included in the following claims.

Page 9 1246878 BRIEF DESCRIPTION OF THE DRAWINGS The first drawing is a schematic view of a heat dissipating device of the present invention; the second drawing is a schematic view of a heat dissipating device of the present invention in combination with a heat generating electronic component. [Description of component symbols] Heat sink 5 Heat dissipating component 51 Surface 510 Substrate 511 Heat dissipating film 512 Phase change thermal pad 53 Heating element 6 Fastening device 7

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Claims (1)

1246878 t, the scope of patent application 1. A phase change thermally conductive sheet comprising: a phase change thermally conductive material comprising: a matrix; and a plurality of filler particles dispersed in the matrix; wherein the filler particles comprise nanocarbon spheres. 2. The phase change thermally conductive sheet of claim 1, wherein the substrate is a polymer matrix. 3. The phase change thermally conductive sheet of claim 2, wherein the polymer matrix is selected from the group consisting of paraffin resins, enamel resins, acrylic resins, epoxy resins, polyurethanes, polyethers, and acrylics. S purpose. 4. The phase change thermally conductive sheet of claim 2, wherein the filler particles further comprise refractory particles selected from the group consisting of Ni, Cu, Ag, Sn, A1, A1203, BN , AIN and ceramic materials. 5. The phase change thermally conductive sheet of claim 2, wherein the filler particles further comprise fusible particles selected from the group consisting of I η, In/Sn, In/Ag, Sn/Ag, Sn /In/Ag, Sn/Ag/Cu, Sn/Bi, In/Sn/Bi, and In/Zn 〇 6. The phase change thermally conductive sheet of claim 2, wherein the polymer matrix further comprises a crosslinking agent. 7. The phase change thermally conductive sheet of claim 1, wherein the nanospheres have a diameter ranging from 5 to 50 nm. 8. The phase change thermally conductive sheet of claim 1, wherein the nanocarbon spheres are filled with metal particles. 9. The phase change thermally conductive sheet of claim 1, wherein the Page 11 1246878 VI. The substrate of the patent application scope is selected from the group consisting of In, In/Sn, In/Ag, Sn/Ag, Sn/In/Ag, Sn/Ag/Cu, Sn/Bi, In/Sn/Bi and In. /Zn. The phase change thermally conductive sheet of claim 1, wherein the phase change thermally conductive sheet further comprises a carrier for supporting the phase change thermal conductive material, comprising two opposite surfaces, the phase change heat conduction The material is formed on opposite surfaces of the carrier. 1 1. The phase change thermally conductive sheet of claim 10, wherein the carrier is aluminum or an insulator. The phase change thermally conductive sheet of claim 1, wherein the phase change thermal conductive material has a solid liquid phase change temperature ranging from 50 to 70 °C. The phase change thermally conductive sheet of claim 1, wherein the phase change thermally conductive sheet further comprises a protective layer covering the surface thereof. 14. A heat sink comprising: a heat dissipating component comprising a surface; and a phase change thermally conductive sheet attached to the surface of the heat dissipating component, comprising: a phase change thermally conductive material comprising: a substrate; and a dispersion The plurality of particles are filled in the matrix; wherein the filler particles comprise nanocarbon spheres. The heat dissipating device of claim 14, wherein the heat dissipating component is a heat conducting plate, a heat sink or a heat pipe. The heat dissipating device of claim 14, wherein the substrate is a polymer matrix. 1 7. The heat sink of claim 16, wherein Page 12 1246878 VI. The polymer matrix of the patent application scope is selected from the group consisting of stone asphalt resin, enamel resin, acrylic resin, epoxy resin, urethane rubber, polyether and acrylate. The heat dissipating device of claim 1, wherein the filler particles further comprise refractory particles selected from the group consisting of Ni, Cu, Ag, Sn, A1, A12〇3 , BN, A 1 N and ceramic materials. The heat dissipating device of claim 16, wherein the filler particles further comprise readily soluble particles selected from the group consisting of I η, In/Sn, In/Ag, Sn/Ag, Sn/ In/Ag, Sn/Ag/Cu, Sn/Bi, In/Sn/Bi, and In/Zn. The heat dissipating device of claim 6, wherein the polymer matrix further contains a crosslinking agent. 2 1 The heat sink according to claim 4, wherein the nano carbon spheres have a diameter ranging from 5 to 50 nm. The heat sink according to claim 14, wherein the nanocarbon balls are filled with metal particles. The heat dissipating device according to claim 4, wherein the carcass is selected from the group consisting of In, In/Sn, In/Ag, Sn/Ag, Sn/In/Ag, Sn/Ag/ Cu, Sn/Bi, In/Sn/Bi, and In/Zri. The heat sink of claim i, wherein the phase change thermally conductive sheet further comprises a protective layer disposed on a surface away from the heat dissipating component. The heat dissipating device according to claim 4, wherein the phase change thermal conductive material has a solid liquid phase change temperature ranging from 50 to 70 °C. Page 13