TWI859950B - Heat sink - Google Patents

Abstract

The heat dissipation device of the present invention includes a substrate, a heat source, a heat dissipation module and a heat conductive layer. The heat source is connected to the substrate. The heat conductive layer is connected to the heat dissipation module and the heat source, and includes a phase change heat conductive unit and a wall structure. The phase change heat conductive unit is distributed on the heat source. The wall structure extends outward from the phase change heat conductive unit to cover the phase change heat conductive unit, and the wall structure is located between the substrate and the heat dissipation module.

Description

Heat sink

The present invention relates to a heat sink, and in particular to a heat sink using a phase change material.

The heat energy generated by the operation of the processor or electronic components of electronic devices will increase with the increase of computing speed and performance. The heat energy accumulation will cause the temperature of the processor or electronic components to rise, which will not only affect the processing capacity of the processor or electronic components but also affect the service life.

Furthermore, as electronic devices move towards lighter, thinner, shorter and smaller sizes, efficient heat dissipation has become an important issue. Liquid metal thermal paste has a higher thermal conductivity than traditional thermal paste. In order to improve heat dissipation efficiency, liquid metal thermal paste has been used in heat dissipation environments. However, it is difficult to restrict the flow of liquid metal thermal paste when it is in liquid form, and it is easy to overflow into the environment around the processor or electronic components, causing short circuits in the surrounding circuits. Alternatively, as in Taiwan Patent No. I698287, the surface of the electronic component is roughened within the range of the restricted component before applying the liquid metal thermal paste to increase the uniformity of the liquid metal thermal paste. Although this method can improve the range and uniformity of the coating, the liquid metal will still flow outward during the heat conduction (dissipation) process and overflow to the outside, causing a short circuit problem in the surrounding circuit.

In view of the above-mentioned deficiencies, the heat conductive layer of the heat dissipation device of the present invention can effectively limit the flow of the phase change conductive material to avoid the problem of circuit short circuit caused by overflow of the conductive material.

In order to achieve the above-mentioned purpose, the heat dissipation device of the present invention includes a substrate, a heat source, a heat dissipation module and a heat conductive layer. The heat source is connected to the substrate. The heat conductive layer is connected to the heat dissipation module and the heat source, and includes a phase change heat conductive unit and a wall structure. The phase change heat conductive unit is distributed on the heat source. The wall structure extends outward from the phase change heat conductive unit to cover the phase change heat conductive unit, and the wall structure is located between the substrate and the heat dissipation module.

In this way, the heat dissipation device of the present invention can enclose the phase change heat conducting unit through the wall structure of the heat conducting layer to limit the overflow of the liquid conductive material to the outside of the wall structure and improve the circuit short circuit problem.

The detailed structure or features of the heat dissipation device provided by the present invention will be described in the detailed description of the implementation method in the following. However, those skilled in the art should understand that the detailed description and the specific embodiments listed for implementing the present invention are only applicable to the description of the present invention and are not intended to limit the scope of the patent application of the present invention.

10: Heat dissipation device

20: Substrate

30: Heat source

40: Heat dissipation module

50: Thermal conductive layer

51: Phase change heat conduction unit

511: Phase change conductive material

513: Insulation and thermal conductive materials

53: Wall structure

531: First contact surface

533: Second contact surface

535: Internal retaining wall

537:External wall

Figure 1 is a schematic diagram of an embodiment of the heat dissipation device of the present invention.

FIG2 is a schematic diagram of an embodiment in which the heat dissipation module and the heat source are pressed together in a side view in FIG1 and the heat conductive layer is presented in a cross-sectional view.

FIG3 is a schematic diagram of another embodiment in which the heat dissipation module and the heat source are pressed together in a side view in FIG1 and the heat conductive layer is presented in a cross-sectional view.

The applicant first explains that throughout the entire specification, including the embodiments described below and the claims of the patent application, the terms related to direction are based on the directions in the drawings. Secondly, in the embodiments and drawings to be described below, the same component numbers represent the same or similar components or their structural features.

As shown in FIG. 1 and FIG. 2 , the heat dissipation device 10 of the present invention includes a substrate 20, a heat source 30, a heat dissipation module 40 and a heat conductive layer 50. The heat source 30 is connected to the substrate 20. The substrate 20 may have other electronic components, such as passive components or active components. The heat source 30 is, for example, a chip. The heat dissipation module 40 may be in the form of a heat dissipation fin, a heat dissipation cover, a heat dissipation plate, a heat dissipation pipe, etc., or may be combined with an active heat dissipation device, such as water-cooled or air-cooled heat dissipation. The heat conductive cover covers the heat source 30, and another heat dissipation module may be combined on the heat conductive cover. The heat conductive layer 50 connects the heat dissipation module 40 and the heat source 30. The heat conductive layer 50 includes a phase change heat conductive unit 51 and a wall structure 53. The phase change thermal conductive unit 51 includes a phase change conductive material 511 and an insulating thermal conductive material 513 mixed together.

The raw material of the heat conductive layer 50 can be in the form of paste, mud, glue, sheet, liquid, etc. The raw material of the heat conductive layer 50 is also called filler, heat dissipation material or heat conductive material, etc., and can be filled on the heat source 30 by coating, dispensing, printing, placement, etc., or a heat dissipation film is attached to the heat source 30, and then the heat dissipation module 40 and the heat source 30 are pressed, and the heat dissipation paste or heat dissipation film is squeezed, so that the heat dissipation paste or heat dissipation film conforms to the surface fluctuations of the heat dissipation module 40 and the heat source 30 and combines with each other.

The heat dissipation paste, heat dissipation glue or heat dissipation material includes a low-density insulating thermal conductive material 513 and a high-density phase change conductive material 511. Therefore, no matter how the low-density insulating thermal conductive material 513 is squeezed, it can surround the phase change conductive unit 51. Subsequently, the low-density insulating thermal conductive material 513 on the periphery of the thermal conductive layer 50 can form a wall structure 53 to surround the internal mixed material (i.e., the insulating thermal conductive material 513 and the phase change conductive material 511).

Since the heat-conducting layer 50 is squeezed by the heat dissipation module 40 and the outer wall structure 53 is formed, the wall structure 53 is an irregular pattern. In other embodiments, the heat-conducting layer 50 is confined in a specific frame, and the wall structure 53 is limited by the pattern of the frame. For example, if the heat-conducting layer 50 is in a hollow rectangular frame, the squeezed heat-conducting layer 50 pattern will be similar to a rectangular frame.

The density of the insulating thermally conductive material 513 is lower than that of the phase change conductive material 511. The phase change conductive material 511 has better cohesion. The insulating thermally conductive material 513 includes a base oil and an additive. The base oil can be synthetic oil, semi-synthetic oil, mineral oil, or other oils, such as dimethyl silicone oil, phenyl silicone oil, ethyl silicone oil, hydroxyl silicone oil, amino silicone oil, hydrogenated silicone oil, vinyl silicone oil, modified silicone oil, cyclic dimethyl silicone oil, or benzyl silicone oil. The additive may be at least one of dimethyldichlorosilane, acrylsilane, phenyltrichlorosilane, methacrylic silane, phenyltrimethoxysilane, epoxysilane, decyltrimethoxysilane, trimethoxysilane, trifluoropropyltrimethoxysilane, vinyltrichlorosilane, hexamethyldisilazane, methyldiethoxysilane, tetraethoxysilane, styryltrimethoxysilane, methyltrichlorosilane, 3-methacryloyloxypropyl, N-vinylbenzyl-2-aminoethyl-3-aminopropyltrimethoxysilane hydrochloride, 3-ureidopropyltriethoxysilane, 3-butylpropyltrimethoxysilane, 3-isocyanatepropyltriethoxysilane, etc. The phase-change conductive material 511 includes at least one of metals or alloy components such as gold, silver, copper, magnesium, platinum, gallium, indium, manganese, tin, lead, zinc, bismuth, and palladium. Because the density of the insulating thermal conductive material 513 is lower than that of the phase-change thermal conductive unit 51, the phase-change conductive material 511 will be coated by the insulating thermal conductive material 513 during the extrusion process and push the insulating thermal conductive material 513.

The phase change heat conducting unit 51 is distributed on the heat source 30. The phase change conductive material 511 is a component or substance with high melting heat, and undergoes phase change (such as melting or solidification) when heated to a specific temperature parameter. In this embodiment, the phase change is to change the solid state into the liquid state after heating. In this way, the state change of the phase change is used to absorb or release heat energy.

The composition of the wall structure 53 is the result of the solidification of part of the insulating heat conductive material 513 in the phase change heat conductive unit 51. The wall structure 53 extends outward from the phase change heat conductive unit 51 to cover the phase change heat conductive unit 51. In this way, the phase change heat conductive unit 51 is confined within the wall structure 53 to improve the phase change conductive material 511 in the phase change heat conductive unit 51 from overflowing to the outside of the wall structure 53 when in liquid state.

As shown in FIG. 2 , the wall structure 53 includes a first contact surface 531, a second contact surface 533, an inner barrier wall 535, and an outer barrier wall 537. The first contact surface 531 contacts the heat dissipation module 40 and conforms to the surface fluctuations of the heat dissipation module 40. The second contact surface 533 contacts the substrate 20 and conforms to the surface fluctuations of the substrate 20 and the heat source 30. The first contact surface 531 and the second contact surface 533 are generally not exposed to the environment. The inner barrier wall 535 connects the periphery of the first contact surface 531 and the second contact surface 533 and surrounds the phase change heat conductive unit 51 to prevent the phase change conductive material 511 of the liquid phase change heat conductive unit 51 from leaking out. The outer retaining wall 537 connects the first contact surface 531 and the second contact surface 533 and surrounds the inner retaining wall 535.

In this embodiment, the wall structure 53 is double-layered, namely, an outer wall 537 and an inner wall 535. The outer wall 537 is exposed to the gap between the heat dissipation module 40 and the substrate 20, and forms a wall similar to a thin film by contacting the air in a normal temperature environment. The inner wall 535 is solidified after receiving heat energy (i.e., being heated). The heat energy can be external heating, such as heat energy generated by a heating chamber or by the operation of the heat source 30, so that the heat conductive layer 50 forms the wall structure 53. After the wall structure 53 is formed, the phase change heat conductive unit 51 inside the wall structure can maintain the paste and heat conductive function to allow the phase change conductive material 511 to undergo phase change.

As shown in FIG3 , the heat source 30 includes a heat generating surface 31, and the heat generating surface 31 faces away from the substrate 20. The wall structure 53 connects the heat generating surface 31 of the heat generating source 30 and the heat dissipation module 40. The second contact surface 533 contacts the heat generating surface 31 of the heat generating source 30 and conforms to the surface undulations of the heat generating surface 31.

In this way, the double-layer wall structure 53 can make the structure of the heat-conducting layer 50 more stable to prevent the phase-change conductive material 511 of the liquid phase-change heat-conducting unit 51 from leaking or overflowing outside the wall structure 53. Furthermore, the heat source 30, the heat dissipation module 40 and the heat-conducting layer 50 are in close contact, and the heat conduction capacity of the phase-change conductive material 511 in the phase-change heat-conducting unit 51 is better than that of the insulating heat-conducting material 513. Therefore, when the phase-change conductive material 511 receives heat energy and changes phase, the heat-conducting layer 50 can more efficiently transfer the heat energy of the heat source 30 to the heat dissipation module 40.

The heat dissipation device of the present invention can transfer the heat energy of the heat source to the heat dissipation module through the formation of a heat conductive layer, and optimize the heat conduction capacity through the phase change conductive material with better heat conductivity in the heat conductive layer, and surround the phase change conductive material with a wall structure formed by the heat conductive layer itself. In this way, when the phase change conductive material changes to a liquid state, the liquid phase change conductive material is restricted by the wall structure and will not leak out of the wall structure.

Finally, the components disclosed in the above-mentioned embodiments of the present invention are only for illustration and are not intended to limit the scope of the present invention. Replacements or changes of other equivalent components should also be covered by the scope of the patent application of the present invention.

10: Heat dissipation device

20: Substrate

30: Heat source

40: Heat dissipation module

50: Thermal conductive layer

51: Phase change heat conduction unit

511: Phase change conductive material

513: Insulation and thermal conductive materials

53: Wall structure

531: First contact surface

533: Second contact surface

535: Internal retaining wall

537:External wall

Claims (8)

A heat dissipation device includes: a substrate; a heat source connected to the substrate; a heat dissipation module; and a heat conductive layer connected to the heat dissipation module and the heat source, and includes a phase change heat conductive unit and a wall structure, the phase change heat conductive unit includes a mixed phase change conductive material and an insulating heat conductive material, the density of the insulating heat conductive material is lower than the density of the phase change conductive material, the wall structure is formed around the phase change heat conductive unit to surround the phase change heat conductive unit and contact the ambient air, the wall structure is related to the insulating heat conductive material of the phase change heat conductive unit, and the wall structure is located between the substrate and the heat dissipation module. The heat dissipation device as described in claim 1, wherein the wall structure includes a first contact surface, a second contact surface, an outer barrier wall and an inner barrier wall, the first contact surface contacts the heat dissipation module, the second contact surface contacts the substrate, the inner barrier wall connects the first contact surface and the second contact surface around and surrounds the phase change heat conduction unit, and the outer barrier wall connects the first contact surface and the second contact surface around and surrounds the inner barrier wall. The heat dissipation device as described in claim 1, wherein the heat source includes a heat generating surface, the heat generating surface is opposite to the substrate, the wall structure includes a first contact surface, a second contact surface, an outer barrier wall and an inner barrier wall, the first contact surface contacts the heat dissipation module, the second contact surface contacts the heat generating surface, the inner barrier wall connects the first contact surface and the second contact surface around, and surrounds the phase change heat conducting unit, the outer barrier wall connects the first contact surface and the second contact surface around, and surrounds the inner barrier wall. A heat dissipation device as described in claim 2 or 3, wherein the inner wall of the enclosure structure is formed by heat energy, and the outer wall is formed by contact with ambient air. A heat dissipation device as described in claim 1, wherein the inner wall of the enclosure structure is formed by thermal energy. A heat dissipation device as described in claim 1, wherein the inner and outer walls of the enclosure structure are in irregular shapes. A heat dissipation device as described in claim 1, wherein the phase change heat conductive unit includes a phase change conductive material and an insulating heat conductive material mixed together, and the phase change conductive material includes a solid state that is heated to change into a liquid state. A heat dissipation device as described in claim 7, wherein the wall structure is the result of a portion of the insulating thermally conductive material being solidified.

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