An ultra-thin heat spreader with separated gas-liquid channels

Abstract

The present invention relates to a heat spreader, and in particular to an ultra-thin heat spreader with separated gas-liquid channels. The ultra-thin heat spreader with separated gas-liquid channels of the present invention comprises a cover plate and a bottom plate, the cover plate and the bottom plate are sealed and connected at their peripheries to form a sealed working medium cavity, the sealed working medium cavity is in a vacuum state, and is filled with a liquid working medium, the inner surface of the cover plate is a concave surface, comprising a first area and a second area, wherein the first area is provided with regularly arranged support columns, and the second area is not provided with support columns, and is used to place a foam copper wick, the upper surface of the foam copper wick is tightly fitted with the lower surface of the cover plate, and the lower surface of the foam copper wick is tightly fitted with the upper surface of the bottom plate. The thickness of the ultra-thin heat spreader of the present invention is 0.20-0.30mm, the gap between the support columns on the inner side of the cover plate is a steam channel, and the foam copper wick is a working medium channel, the two are independent of each other, and can effectively reduce the gas-liquid flow resistance, and solve the problem of local high heat flow heat dissipation of microelectronic devices in confined spaces.

Description

Technical Field

[0001] The invention relates to a vapor chamber, and in particular to an ultra-thin vapor chamber with separated gas-liquid channels. Background Art

[0002] With the advancement of 5G network construction, the functions of 5G terminal equipment have become more diversified. Chips need to cope with complex environmental conditions, and their high-speed operation will bring high heat problems. When meeting the requirements of high integration, thinness and maximum space utilization of terminal equipment at the same time, it is necessary to consider the use of ultra-thin heat spreaders. Due to the fine and varied internal structure of the heat spreader and the very complex phase change heat transfer mechanism, there are many factors that affect the heat transfer performance. As the heat spreader develops towards ultra-thinness, it is necessary to comprehensively consider various design problems.

[0003] Research shows that below the critical thickness of 0.3mm, as the thickness further decreases, the heat transfer resistance of the steam chamber will rise rapidly, causing the overall heat transfer performance of the vapor chamber to decrease. For existing ultra-thin vapor chambers below 0.3mm, the space is extremely limited, and there is a problem of insufficient thickness of the vapor chamber. In addition, the spatial distribution of the capillary wick and the vapor chamber is divided into upper and lower layers. For example, the upper space of the vapor chamber is the steam channel, and the lower space is the working fluid channel. This upper and lower layer division method further reduces the thickness of the vapor chamber, and the vapor-liquid interface is equivalent to the radial area of ​​the entire vapor chamber, with a large contact area and large gas-liquid flow resistance. Summary of the invention

[0004] The technical problem to be solved by the present invention is to provide an ultra-thin heat spreader with separated gas-liquid channels in view of the deficiencies of the above-mentioned prior art. The present invention flexibly combines the overall structural design of the heat spreader with welding technology, and provides an ultra-thin heat spreader with a thickness of 0.20-0.30 mm. The foam copper wick is the liquid working medium channel, and the gap between the supporting columns around the foam copper wick is the steam channel. The two are independent of each other. The left and right separation of the gas-liquid channel can effectively reduce the gas-liquid flow resistance. The steam channel running through the upper and lower cover plates can ensure sufficient thickness in the vertical direction, so that the heat transfer thermal resistance of the steam chamber is significantly reduced, thereby improving the overall thermal resistance of the heat spreader to a certain extent, which can effectively solve the local high heat flux heat dissipation problem of microelectronic devices in confined spaces.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions: an ultra-thin heat spreader with separated gas-liquid channels, comprising a cover plate and a bottom plate, wherein the cover plate and the bottom plate are sealed and connected at their peripheries to form a sealed working medium cavity, wherein the sealed working medium cavity is in a vacuum state and is filled with a liquid working medium, wherein the inner surface of the cover plate is a concave surface, comprising a first area and a second area, wherein the first area is provided with regularly arranged support columns, and the second area is not provided with support columns, and is used to place a foam copper liquid absorbent core, wherein the upper surface of the foam copper liquid absorbent core is tightly fitted with the lower surface of the cover plate, and the lower surface of the foam copper liquid absorbent core is tightly fitted with the upper surface of the bottom plate.

[0006] The wall thickness of the cover plate is 0.13-0.20 mm, the wall material is made of stainless steel or titanium, and the inner wall is copper-plated.

[0007] The wall thickness of the bottom plate is 0.07-0.12 mm, the wall material is made of stainless steel or titanium, the inner wall is copper-plated, and the inner surface of the bottom plate is roughened.

[0008] The concave surface and the support column on the inner surface of the cover plate are formed by chemical etching, and the support column includes a small cylinder and a long column.

[0009] The thickness of the foam copper wick is 0.07-0.15 mm, and the shape of the foam copper wick matches the shape of the second region. On the premise of ensuring that there are enough wicks at the heat source, the foam copper wick runs through the plane of the heat spreader.

[0010] The foam copper liquid absorbing core is treated for hydrophilicity by magnetron sputtering titanium dioxide plating, thermal oxidation or plasma cleaning.

[0011] When the inner surface of the bottom plate is roughened, a physical method is used to form a continuous capillary structure with a fuzzy morphology on the inner surface of the bottom plate.

[0012] When the inner surface of the bottom plate is roughened, a hydrophilic porous structure is formed on the inner surface of the bottom plate by a chemical or electrochemical method.

[0013] The cover plate and the bottom plate are brazed to achieve peripheral sealing connection, and the inner surface of the bottom plate has a structure with a high center and low surroundings.

[0014] The cover plate and the base plate are connected in a peripheral sealing manner by diffusion welding, a microchannel is arranged on the inner surface of the base plate, and the inner side surface of the base plate is integrated with the support column by diffusion welding.

[0015] Compared with the prior art, the present invention has the following advantages:

[0016] (1) The inner surface of the cover plate of the present invention is arrayed with a plurality of support columns, which include a plurality of small cylinders and long columns. The long columns strengthen the support and have a certain flow-guiding effect on the flowing steam. Part of the inner side of the cover plate is free of support columns, which are used to place the foam copper wick. A foam copper wick of a certain thickness is arranged in the space on the inner side of the cover plate where no support columns are arranged. To ensure sufficient capillary force, the wick will increase its axial thickness while reducing its radial area. The shape of the foam copper wick is flexibly designed according to the position of the heat source and the overall shape of the heat spreader.

[0017] (2) The gap between the inner support columns of the cover plate of the present invention is a steam channel, and the foam copper liquid absorption core is a working fluid channel. The two are independent of each other and can effectively reduce the gas-liquid flow resistance.

[0018] (3) The difference in thickness distribution between the cover plate and the bottom plate of the present invention is more obvious. As the cover plate becomes thicker, the thickness of the steam chamber increases, which can effectively reduce the thermal resistance of the steam chamber. The wall materials of the cover plate and the bottom plate are copper, stainless steel or titanium, and the inner wall is copper-plated. Stainless steel or titanium can ensure the strength of the plate body, and the inner copper plating can ensure the hydrophilicity of the wall.

[0019] (4) The present invention performs hydrophilic treatment on the copper foam wick, adopts magnetron sputtering titanium dioxide coating, thermal oxidation or plasma cleaning, etc., to enhance the hydrophilicity of the copper foam; micro-grooves are etched on the inner surface of the bottom plate, and a composite liquid wick structure is formed with the copper foam to effectively enhance the capillary force.

[0020] (5) The present invention etches the skirt of the bottom plate to leave space for solder paste, which can effectively save the thickness required for solder paste. At this time, the skirt-etched bottom plate and the cover plate are combined into one by brazing. When the bottom plate has no skirt etching, diffusion welding is adopted, which is efficient and simple, and the overall strength is more guaranteed. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural exploded view of the ultra-thin heat spreader with separated liquid channels according to Example 1 of the present invention.

[0022] Figure 2 It is a schematic diagram of the matching structure of the foam copper liquid absorbing core and the cover plate in Example 1 of the present invention.

[0023] Figure 3 It is a schematic diagram of the brazing connection structure of the cover plate and the base plate in Example 1 of the present invention.

[0024] Figure 4 It is a structural decomposition diagram of the ultra-thin heat spreader with separated liquid channels according to Example 2 of the present invention.

[0025] Figure 5 It is a schematic diagram of the matching structure of the foam copper liquid absorbing core and the cover plate in Example 2 of the present invention.

[0026] Figure 6 It is a schematic diagram of the brazing connection structure of the cover plate and the base plate in Example 2 of the present invention.

[0027] In the figure: 1-cover plate; 2-bottom plate; 3-foam copper wick; 4-solder paste; 10-first area; 11-second area; 101-support column; 1011-small cylinder; 1012-long column. DETAILED DESCRIPTION

[0028] The specific implementation of the present invention is described in detail below in conjunction with the technical scheme and the accompanying drawings.

[0029] Example 1

[0030] like Figure 1-2 As shown, an ultra-thin heat spreader with separated gas-liquid channels comprises a cover plate 1 and a bottom plate 2, wherein the cover plate 1 and the bottom plate 2 are sealed and connected at their peripheries to form a sealed working medium cavity, wherein the sealed working medium cavity is in a vacuum state and is filled with liquid working medium water, wherein the inner surface of the cover plate 1 is a concave surface, comprising a first area 10 and a second area 11, wherein the first area 10 is provided with regularly arranged support columns 101, and the second area 11 is not provided with support columns 101, and is used to place a foam copper liquid absorbent core 3, wherein the upper surface of the foam copper liquid absorbent core 3 is tightly fitted with the lower surface of the cover plate 1, and the lower surface of the foam copper liquid absorbent core 3 is tightly fitted with the upper surface of the bottom plate 2.

[0031] The wall thickness of the cover plate 1 is 0.18 mm, the wall material is made of stainless steel, and the inner wall is copper-plated. Stainless steel or titanium can ensure the strength of the plate, and the inner copper plating ensures the hydrophilicity of the wall.

[0032] The wall thickness of the bottom plate 2 is 0.07 mm, the wall material is made of stainless steel, the inner wall is copper-plated, and the inner surface of the bottom plate 2 is roughened.

[0033] The concave surface on the inner surface of the cover plate 1 and the support column 101 are formed by chemical etching. The concave surface is used as a steam chamber, and the support column is used to provide support strength. The support column 101 includes a small cylinder 1011 and a long column 1012, and the long column 1012 is located at the periphery.

[0034] The thickness of the foam copper wick 3 is 0.12 mm, and the shape of the foam copper wick 3 is F-shaped, which is adapted to the shape of the second region 11. On the premise of ensuring that there are enough wicks at the heat source, the foam copper wick 3 runs through the plane of the heat spreader. The foam copper wick 3 is initially fixed to the inner concave surface of the cover plate by spot welding, and then sintered into one with the bottom plate.

[0035] When the inner surface of the bottom plate 2 is roughened, a physical method is used to form a continuous capillary structure with a fuzzy morphology on the inner surface of the bottom plate 2 .

[0036] like Figure 3 As shown, the cover plate 1 and the base plate 2 are brazed to achieve peripheral sealing connection. The inner surface of the base plate 2 is a structure with a high center and low surroundings. A skirt is etched around the base plate to leave space for solder paste. A circle of solder paste 4 is dotted around the etched base plate and fired into one piece with the upper cover plate.

[0037] Example 2

[0038] like Figure 4-5As shown, an ultra-thin heat spreader with separated gas-liquid channels comprises a cover plate 1 and a bottom plate 2, wherein the cover plate 1 and the bottom plate 2 are sealed and connected at their peripheries to form a sealed working medium cavity, wherein the sealed working medium cavity is in a vacuum state and is filled with liquid working medium water, wherein the inner surface of the cover plate 1 is a concave surface, comprising a first area 10 and a second area 11, wherein the first area 10 is provided with regularly arranged support columns 101, and the second area 11 is not provided with support columns 101, and is used to place a foam copper liquid absorbent core 3, wherein the upper surface of the foam copper liquid absorbent core 3 is tightly fitted with the lower surface of the cover plate 1, and the lower surface of the foam copper liquid absorbent core 3 is tightly fitted with the upper surface of the bottom plate 2.

[0039] The wall thickness of the cover plate 1 is 0.15 mm, the wall material is made of titanium, and the inner wall is copper-plated. Stainless steel or titanium can ensure the strength of the plate, and the inner copper plating ensures the hydrophilicity of the wall.

[0040] The wall thickness of the bottom plate 2 is 0.08 mm, the wall material is made of titanium, the inner wall is copper-plated, and the inner surface of the bottom plate 2 is roughened.

[0041] The concave surface on the inner surface of the cover plate 1 and the support column 101 are formed by chemical etching. The concave surface is used as a steam chamber, and the support column is used to provide support strength. The support column 101 includes a small cylinder 1011 and a long column 1012, and the long column 1012 is located at the periphery.

[0042] The thickness of the foam copper wick 3 is 0.10 mm, and the shape of the foam copper wick 3 is F-shaped, which is adapted to the shape of the second area 11. On the premise of ensuring that there are enough wicks at the heat source, the foam copper wick 3 runs through the plane of the heat spreader. The foam copper wick 3 is initially fixed to the inner concave surface of the cover plate by spot welding, and then sintered into one with the bottom plate.

[0043] When the inner surface of the bottom plate 2 is roughened, a thermal oxidation method is used to form a hydrophilic porous structure on the inner surface of the bottom plate 2: the copper sheet is immersed in a roughening treatment liquid for roughening treatment, and after oxidation, residual oxides, oil stains and other impurities on the copper surface are removed, and the copper sheet is placed in an oven for drying to obtain a roughened surface.

[0044] like Figure 6 As shown, when the cover plate 1 and the base plate 2 are connected by diffusion welding to achieve peripheral sealing, a microchannel is etched on the inner surface of the base plate 2, and the inner side surface of the base plate 2 is combined with the support column 101 by diffusion welding. The microchannel is used to enhance the capillary force inside the heat spreader.

[0045] Inside the heat spreader, the liquid working medium exists in the foam copper or microchannel. When it starts working, the liquid working medium evaporates due to heat to form steam. The steam flows along the gaps between the support columns, and the heat diffuses to the far end of the heat source. The liquid working medium formed after the steam condenses flows back to the heat source through the capillary force of the liquid absorption core, and this cycle continues. This ultra-thin heat spreader uses the principle of phase change heat transfer to effectively solve the heat dissipation problem of electronic components with high heat flux density in a small space.

[0046] The above is only a preferred embodiment of the present invention and does not limit the present invention in any way. Any simple modification, change and equivalent change made to the above embodiment according to the essence of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. An ultra-thin heat spreader with separated gas-liquid channels, comprising a cover plate (1) and a bottom plate (2), characterized in that: The thickness of the ultra-thin heat spreader is 0.20-0.30 mm. The cover plate (1) and the bottom plate (2) are sealed and connected at their peripheries to form a sealed working medium cavity. The sealed working medium cavity is in a vacuum state and is filled with a liquid working medium. The inner surface of the cover plate (1) is a concave surface, comprising a first area (10) and a second area (11). The first area (10) is provided with regularly arranged support columns (101), and the second area (11) is not provided with support columns (101) and is used to place a foam copper liquid wick (3). The upper surface of the foam copper liquid wick (3) is in close contact with the lower surface of the cover plate (1), and the lower surface of the foam copper liquid wick (3) is in close contact with the upper surface of the bottom plate (2). The concave surface on the inner surface of the cover plate (1) and the support column (101) are formed by chemical etching, and the support column (101) comprises a small cylinder (1011) and a long column (1012); The shape of the foam copper wick (3) matches the shape of the second region (11), and the foam copper wick (3) runs through the plane of the heat spreader while ensuring that there are sufficient wicks at the heat source.

2. The ultra-thin heat spreader with separated gas-liquid channels according to claim 1, characterized in that: The wall thickness of the cover plate (1) is 0.13-0.20 mm, the wall material is made of stainless steel or titanium, and the inner wall is copper-plated.

3. The ultra-thin heat spreader with separated gas-liquid channels according to claim 1, characterized in that: The wall thickness of the bottom plate (2) is 0.07-0.12 mm, the wall material is made of stainless steel or titanium, the inner wall is copper-plated, and the inner surface of the bottom plate (2) is roughened.

4. The ultra-thin heat spreader with separated gas-liquid channels according to claim 1, characterized in that: The thickness of the foam copper liquid absorbing core (3) is 0.07-0.15 mm.

5. The ultra-thin heat spreader with separated gas-liquid channels according to claim 1, characterized in that: The foam copper liquid absorbing core (3) is treated to be hydrophilic by magnetron sputtering titanium dioxide, thermal oxidation or plasma cleaning.

6. The ultra-thin heat spreader with separated gas-liquid channels according to claim 3, characterized in that: When the inner surface of the bottom plate (2) is roughened, a physical method is used to form a continuous capillary structure with a fuzzy morphology on the inner surface of the bottom plate (2).

7. The ultra-thin heat spreader with separated gas-liquid channels according to claim 3, characterized in that: When the inner surface of the bottom plate (2) is roughened, a hydrophilic porous structure is formed on the inner surface of the bottom plate (2) using a chemical or electrochemical method.

8. The ultra-thin heat spreader with separated gas-liquid channels according to claim 1, characterized in that: The cover plate (1) and the bottom plate (2) are brazed to achieve peripheral sealing connection, and the inner surface of the bottom plate (2) has a structure with a high center and low surrounding areas.

9. The ultra-thin heat spreader with separated gas-liquid channels according to claim 1, characterized in that: The cover plate (1) and the base plate (2) are connected in a peripheral sealed manner by diffusion welding, a microchannel (20) is provided on the inner surface of the base plate (2), and the inner side surface of the base plate (2) and the support column (101) are integrated by diffusion welding.

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