Ultra-thin heat spreader with composite liquid wick structure and manufacturing method thereof

Abstract

The present invention discloses an ultra-thin heat spreader with a composite liquid wick structure and a manufacturing method thereof, including an evaporation plate and a condensation plate, a concave cavity is arranged on the inner surface of the evaporation plate, and a first capillary structure and a second capillary structure are arranged in the concave cavity; the first capillary structure is a microchannel groove structure processed integrally with the evaporation plate, and the second capillary structure is a porous metal structure formed by sintering; a third capillary structure is arranged on the inner surface of the condensation plate, and the third capillary structure is a circular array microchannel with an emitting shape; the manufacturing method of the present invention includes integral processing of the evaporation plate concave cavity and the first capillary structure, sintering of the second capillary structure, processing of the condensation plate, cleaning and sealing welding, and vacuuming and liquid injection. The heat spreader with a composite liquid wick structure of the present invention has the characteristics of thin thickness, high permeability, high support strength, high heat dissipation efficiency, and reversible gravity.

Description

Technical Field

[0001] The invention relates to the technical field of heat dissipation of microelectronic devices, and in particular to an ultra-thin vapor chamber with a composite liquid wick structure and a manufacturing method thereof. Background Art

[0002] With the integration and complexity of electronic devices, the heat generation per unit area of ​​electronic devices is getting higher and higher. How to achieve efficient heat dissipation of high heat flux electronic devices has become the key to the development of electronic equipment technology. The heat spreader uses the principle of phase change heat transfer to quickly diffuse the concentrated heat to a larger condensation surface, thereby effectively reducing the heat flux density of the electronic device. For this reason, the heat spreader technology is favored by researchers in the field of electronic equipment heat dissipation.

[0003] Existing heat spreaders are generally flat plates, consisting of an evaporation plate, a condensation plate, and a corresponding liquid wick. During operation, the heat from the heat source is transferred to the liquid working medium through the wall shell of the evaporation surface and the liquid wick, causing the liquid working medium to boil and vaporize due to the temperature rise; the gaseous working medium is transferred to the condensation surface, and after releasing heat, it condenses back into liquid. The liquid working medium returns to the evaporation end by gravity or the capillary force of the evaporation tank, completing a working cycle, and repeats this process, thereby achieving rapid diffusion of heat from a concentrated area to the entire condensation surface. However, the existing heat spreader technology still has the following deficiencies:

[0004] 1. Existing vapor chambers generally retain the steam cavity as a vapor diffusion channel. This structure has low strength and is easily deformed, resulting in poor contact, which causes a sharp drop in the heat dissipation performance of the vapor chamber. On the other hand, the existence of the steam cavity structure makes it more difficult to make the vapor chamber ultra-thin, making the processing more complicated and costly.

[0005] 2. Most of the existing vapor chamber wicks are formed by sintering porous metals, which have large flow resistance, low permeability and low heat dissipation efficiency.

[0006] 3. Some existing vapor chambers use channel-type liquid wicks, which have high permeability and low flow resistance, but weak capillary suction, which cannot provide sufficient reflux power for the working fluid, resulting in reduced heat dissipation efficiency of the vapor chamber. On the other hand, the existing channel-type liquid wick vapor chambers have poor anti-gravity effect and can only be installed horizontally.

[0007] 4. The existing heat spreader is thick. If the thickness is reduced or a slight stress deformation occurs, the thermal resistance will increase sharply. Summary of the invention

[0008] In order to overcome the shortcomings and deficiencies of the prior art, the first purpose of the present invention is to provide an ultra-thin heat spreader with a composite liquid absorbent core structure. The present invention has thin thickness, high permeability, small flow resistance, high supporting strength, high heat dissipation efficiency, and reversible gravity.

[0009] The second object of the present invention is to provide a method for manufacturing an ultra-thin vapor chamber with a composite liquid wick structure.

[0010] The present invention adopts the following technical solution:

[0011] An ultra-thin heat spreader with a composite liquid wick structure comprises an evaporation plate and a condensation plate, wherein a heat source is arranged below the evaporation plate, a concave cavity is arranged on the inner surface of the evaporation plate, a first capillary structure and a second capillary structure are arranged in the concave cavity; and a third capillary structure is arranged on the inner surface of the condensation plate.

[0012] Preferably, the first capillary structure is a microchannel groove structure integrally processed with the evaporation plate, and the second capillary structure is a porous metal structure formed by sintering.

[0013] Preferably, the first capillary structure is annular and distributed in the cavity, and includes a first microchannel structure and a second microchannel structure.

[0014] Preferably, the first microchannel structure is a straight channel diverging from the center of the cavity to the edge, and the channel width gradually increases from the center of the cavity to the edge.

[0015] Preferably, the second microchannel structure is distributed in a network shape, dividing the annular first capillary structure into micro-needle fin structures, and the width of the second microchannel is smaller than that of the first microchannel.

[0016] Preferably, the second capillary structure is placed at the center of the ring of the first capillary structure, and its height is equal to that of the first capillary structure.

[0017] Preferably, the third capillary structure is a radiating circular array of microchannels, and the radiating circular array of microchannels is composed of microchannels that diverge step by step from the center to the edge.

[0018] Preferably, the microchannel comprises multiple levels of three-tree microchannels, each level of the three-tree microchannel comprises a main channel and two secondary channels, the secondary channels of adjacent levels are connected by a connecting channel, and the two secondary channels diverge to both sides of the main channel.

[0019] Preferably, the width and length of the subsequent main channel are less than or equal to the width and length of the previous main channel.

[0020] A method for manufacturing an ultra-thin vapor chamber with a composite liquid wick structure comprises the following steps:

[0021] (1) Integrated processing of the evaporation plate cavity and the first capillary structure: the cavity and the first capillary structure are processed by laser engraving, chemical etching or micro-milling technology;

[0022] (2) Sintering of the second capillary structure: The porous metal plate is sintered at the center of the ring of the first capillary structure by vacuum sintering technology, and its height is controlled to be the same as that of the first capillary structure.

[0023] (3) Condensation plate processing: The third capillary structure is processed on the condensation plate by laser engraving, chemical etching or micro-milling technology;

[0024] (4) Cleaning and sealing welding: Clean the surface of the evaporation plate and the condensation plate, and then weld the evaporation plate and the condensation plate and their capillary structure together by diffusion welding to form a sealed packaging cavity;

[0025] (5) Vacuuming and liquid injection: The interior of the packaging cavity is vacuumed, and the working fluid is injected and then sealed.

[0026] Beneficial effects of the present invention:

[0027] (1) The evaporation plate wick structure of the present invention is composed of a composite capillary structure, which has the characteristics of large capillary force of porous metal sintered wicks and the advantages of large heat exchange area, small flow resistance and high permeability of grooved wicks.

[0028] (2) The first capillary structure of the present invention adopts a composite microchannel structure, wherein the first microchannel structure is a gradually expanding channel from the center of the cavity to the edge. This structural design can provide a certain reflux capillary force for the reflux of the condensed liquid working medium under the premise of ensuring high permeability and low flow resistance, thereby avoiding the phenomenon of the evaporation plate drying out. During operation, the electronic chip is generally located in the center of the evaporation plate, where the evaporation, boiling and gasification effect is strong, and drying out is prone to occur. This composite microchannel structure can alleviate this problem to a certain extent.

[0029] (3) The condensation end of the heat spreader of the present invention adopts an emitting microchannel structure design, which has the advantages of small flow resistance, large capillary suction, large condensation area, short condensation reflux path, and high heat dissipation efficiency.

[0030] (4) The vapor chamber wick of the present invention is mainly a microchannel structure, which avoids the support column structure, has a large support strength, and has strong pressure and heat resistance. It can realize an ultra-thin vapor chamber design without affecting its strength. The microchannel structure can achieve flexibility to a certain extent without affecting its heat dissipation performance.

[0031] (5) The vapor chamber wick structure of the present invention has a hierarchical effect, good anti-gravity effect, low requirements on the installation position, and can achieve horizontal, vertical and flip installation requirements, with wide adaptability.

[0032] (6) The method for manufacturing the heat spreader with a composite liquid wick structure of the present invention is simple and easy to operate, and is suitable for large-scale production. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic structural diagram of an ultra-thin vapor chamber with a composite liquid wick structure according to the present invention;

[0034] Figure 2 for Figure 1 A cross-sectional view of

[0035] Figure 3 for Figure 1 The middle evaporation plate and its partial enlarged schematic diagram;

[0036] Figure 4 for Figure 1 Schematic diagram of the condensation plate structure;

[0037] Figure 5 for Figure 4 Schematic diagram of the structure of one of the condensation zones.

[0038] The accompanying drawings show: 1-evaporation plate; 11-first capillary structure; 111-first microchannel structure; 112-second microchannel structure; 12-second capillary structure; 2-condensation plate; 21-third capillary structure; 211-main channel; 212-secondary channel; 213-connecting channel; 3-heat source. DETAILED DESCRIPTION

[0039] The present invention will be further described in detail below in conjunction with embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0040] Example 1

[0041] like Figure 1-Figure 5 As shown, an ultra-thin heat spreader with a composite liquid wick structure is circular in shape and has an overall height of 0.6 mm. It includes an evaporation plate 1 and a condensation plate 2. A heat source 3 is arranged below the evaporation plate. A concave cavity is arranged on the inner surface of the evaporation plate 1, and a first capillary structure 11 and a second capillary structure 12 are arranged in the concave cavity; the first capillary structure 11 is a microchannel structure integrally processed with the evaporation plate 1, and the second capillary structure 12 is a porous metal structure formed by sintering; a third capillary structure 21 is arranged on the inner surface of the condensation plate 2, and the third capillary structure 21 has a circumferential array microchannel structure with an emitting structure. In this embodiment, the lower surface of the condensation plate, that is, the side opposite to the evaporation plate, is the inner surface, and the inner surface is a convexity.

[0042] In this embodiment, the porous metal structure can be porous foam metal, copper powder sintering and wire mesh sintering.

[0043] In this embodiment, the first capillary structure 11 is a microchannel structure, which is specifically distributed in a circular ring shape in the concave cavity, including a first microchannel structure 111 and a second microchannel structure 112. The first microchannel is a straight channel diverging from the center of the concave cavity to the edge, and the channel width gradually increases from the center of the concave cavity to the edge; the second microchannel structure 112 is distributed in a mesh shape, dividing the circular first capillary structure 11 into micro-needle rib structures, such as Figure 3 As shown in the partially enlarged schematic diagram, the width of the second microchannel is smaller than the width of the first microchannel.

[0044] In this embodiment, the cavity depth is 0.4 mm, and a first microchannel structure 111 and a second microchannel structure 112 are processed in the cavity. The starting width W0 of the first microchannel 111 is 0.2 mm, and the second microchannel 112 is an evenly spaced micro-needle fin structure with a spacing of 0.05 mm. The depth of all microchannels is the same, which is 0.2 mm.

[0045] In this embodiment, a second capillary structure 12 is processed at the center of the evaporation plate cavity. The second capillary structure 12 is sintered from porous foam copper with a porosity of 0.8. It is placed at the center of the ring of the first capillary structure 11 and has the same height as the first capillary structure 11.

[0046] In this embodiment, the condensation plate 2 is processed with a third capillary structure 21, which is an emitting microchannel array. In this embodiment, the third capillary structure 21 includes 12 groups of microchannels in a circular array, each microchannel is a condensation zone, and each group of condensation zones is composed of a 4-level three-tree microchannel structure; the three-tree microchannel structure includes a middle main channel 211 and two secondary channels 212 diverging to both sides; the divergent secondary channels 212 are connected as a whole through the connecting channels 213 on both sides of the condensation zone, and the two secondary channels can be symmetrical about the main channel, the width and length of the rear main channel are less than or equal to the width and length of the previous main channel, and the width of the rear secondary channel is less than or equal to the width of the previous secondary channel, such as Figure 5 As shown; in this embodiment, the length of each main channel is equal, the width of the 0th level main channel is 0.6mm, and then decreases step by step at a ratio of 0.7, and the width of the secondary channel is half of the width of the main channel of the corresponding level; the angle between the main channel 211 and the secondary channel 212 is 30°; the width of the connecting channel is 0.15mm; the depth of all channels is equal, which is 0.2mm.

[0047] The following is a detailed description of the method for making the ultra-thin vapor chamber with a composite liquid wick structure to further demonstrate the structural characteristics and advantages of the ultra-thin vapor chamber, which mainly includes the following steps:

[0048] (1) Integrated processing of the evaporation plate cavity and the first capillary structure 11: The evaporation plate cavity and the first capillary structure 11 are processed by laser engraving technology;

[0049] (2) Sintering of the second capillary structure 12: The porous metal plate is sintered at the center of the ring of the first capillary structure 11 by vacuum sintering technology, and its height is controlled to be the same as that of the first capillary structure.

[0050] (3) Processing of the condensation plate 2: processing the third capillary structure 21 on the condensation plate 2 by laser engraving technology;

[0051] (4) Cleaning and sealing welding: Clean the surface of the evaporation plate and the condensation plate, and then weld the evaporation plate and the condensation plate and their capillary structure together by diffusion welding to form a sealed packaging cavity;

[0052] (5) Vacuuming and liquid injection: The interior of the packaging cavity is vacuumed, and the working fluid is injected and then sealed.

[0053] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be equivalent replacement methods and are included in the protection scope of the present invention.

Claims

1. An ultra-thin vapor chamber with a composite liquid wick structure, characterized in that: It includes an evaporation plate and a condensation plate, wherein a heat source is arranged below the evaporation plate, a concave cavity is arranged on the inner surface of the evaporation plate, a first capillary structure and a second capillary structure are arranged in the concave cavity, and a third capillary structure is arranged on the inner surface of the condensation plate; The first capillary structure is a microchannel groove structure processed integrally with the evaporation plate, and the second capillary structure is a porous metal structure formed by sintering; The first capillary structure is annular and distributed in the cavity, and includes a first microchannel structure and a second microchannel structure; The first microchannel structure is a straight channel diverging from the center of the cavity to the edge, and the channel width gradually increases from the center of the cavity to the edge; The second microchannel structure is distributed in a network shape, dividing the annular first capillary structure into micro-needle fin structures, and the width of the second microchannel is smaller than the width of the first microchannel; The second capillary structure is placed at the center of the ring of the first capillary structure, and its height is equal to that of the first capillary structure; The third capillary structure is a circular array microchannel having an radiating shape, and the circular array microchannel having an radiating shape is composed of microchannels that diverge step by step from the center of the circle to the edge; The microchannel includes multiple levels of three-branch tree microchannels, each level of the three-branch tree microchannel includes a main channel and two secondary channels, the secondary channels of adjacent levels are connected by a connecting channel, and the two secondary channels diverge to both sides of the main channel.

2. The ultra-thin vapor chamber according to claim 1, characterized in that: The width and length of the next main channel are less than The width and length of the previous main channel.

3. A method for manufacturing an ultra-thin vapor chamber with a composite liquid wick structure as claimed in any one of claims 1 to 2, Features: The following steps are involved: (1) Integrated processing of the evaporation plate cavity and the first capillary structure: by laser engraving, chemical etching or micro-milling technology Processing a concave cavity and a first capillary structure; (2) Sintering of the second capillary structure: The porous metal plate is sintered to the ring of the first capillary structure by vacuum sintering technology. center, controlling its height to be the same as that of the first capillary structure; (3) Condensation plate processing: The third hair is processed on the condensation plate through laser engraving, chemical etching or micro milling technology. Fine structure; (4) Cleaning and sealing welding: Clean the surface of the evaporator plate and the condenser plate, and then weld them by diffusion welding. The evaporation plate and the condensation plate as well as their capillary structures are welded together to form a sealed packaging cavity; (5) Vacuuming and liquid injection: The interior of the packaging cavity is vacuumed, and the working fluid is injected and then sealed.

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