A heat plate and a method of manufacturing a heat plate

Abstract

A heat plate has a working fluid in an internal space formed between a first metal sheet and a second metal sheet, the first metal sheet has a recess flow path and at least one or more protrusions, the recess flow path is provided on an inner surface of the first metal sheet, the protrusions protrude from the inner surface of the first metal sheet toward the second metal sheet, and a top surface of the protrusions abuts the second metal sheet, the heat plate has at least one or more top surface joint portions and a gap flow path portion, the top surface joint portions joint a part of the top surface of the protrusions and the second metal sheet, and in the gap flow path portion, the top surface is separated from the second metal sheet.

Description

TECHNICAL FIELD

[0001] The present application relates to a vapor chamber and a manufacturing method of a vapor chamber. BACKGROUND

[0002] For electronic components such as semiconductor elements mounted in electrical / electronic devices such as notebook computers, digital cameras, mobile phones, and the like, there is a tendency for the amount of heat generation to increase due to high-density mounting and the like for high performance. In order to normally drive the electrical / electronic devices for a long time, it is necessary to efficiently cool the electronic components.

[0003] For example, Patent Document 1 describes a vapor chamber having a first metal sheet and a second metal sheet, and provided with a liquid flow path portion in a sealed space provided between the first metal sheet and the second metal sheet. In the vapor chamber of Patent Document 1, for each groove constituting the liquid flow path portion, the width of the first communication groove is greater than the width of the first main flow groove and the width of the second main flow groove, the width of the second communication groove is greater than the width of the second main flow groove and the width of the third main flow groove, the depth of the first communication groove is deeper than the depth of the first main flow groove and the depth of the second main flow groove, and the depth of the second communication groove is deeper than the depth of the second main flow groove and the depth of the third main flow groove.

[0004] In the vapor chamber of Patent Document 1, the first metal sheet and the second metal sheet are joined by diffusion joining, brazing, or the like. When diffusion joining or brazing is performed, the first metal sheet and the second metal sheet as a whole are heat treated and are heat annealed. As such, since the vapor chamber as a whole is heat annealed, the mechanical strength of the vapor chamber decreases. In addition, in the vapor chamber of Patent Document 1, by causing each groove constituting the liquid flow path portion to satisfy a prescribed relationship, an increase in heat transfer efficiency is achieved. However, the increasing requirements for cooling performance in electrical / electronic devices in recent years are not sufficiently met.

[0005] PRIOR ART DOCUMENTS

[0006] PATENT DOCUMENTS

[0007] Patent Document 1: Japanese Patent Application Publication No. 2019-158323 SUMMARY

[0008] PROBLEMS TO BE SOLVED BY THE INVENTION

[0009] An object of the present application is to provide a vapor chamber and a manufacturing method of a vapor chamber, which are excellent in mechanical strength and heat transfer characteristics.

[0010] MEANS FOR SOLVING THE PROBLEMS

[0011] [1] A vapor chamber having a working fluid in an internal space formed between a first metal sheet and a second metal sheet, the vapor chamber being characterized in that the first metal sheet has a recessed flow path provided on an inner surface of the first metal sheet and at least one or more protrusions protruding from the inner surface of the first metal sheet toward the second metal sheet and having a top surface that abuts the second metal sheet, the vapor chamber having at least one or more top surface joint portions that join a portion of the top surface of the protrusion to the second metal sheet, and a gap flow path portion in which the top surface is separated from the second metal sheet.

[0012] [2] The vapor chamber according to the above [1], wherein the gap flow path portion is provided between a top surface abutment portion of the top surface of the first metal sheet that is not joined to the second metal sheet and an inner surface abutment portion of the second metal sheet that abuts the top surface abutment portion, has an occlusion portion on the side of the top surface joint portion of the top surface abutment portion, and has an opening portion on the side of the protrusion of the top surface abutment portion.

[0013] [3] The vapor chamber according to the above [2], wherein a gap length from the occlusion portion to the opening portion in the gap flow path portion is longer than a gap width between the top surface abutment portion and the inner surface abutment portion.

[0014] [4] The vapor chamber according to the above [2] or [3], wherein an average value of the gap width between the top surface abutment portion and the inner surface abutment portion in the gap flow path portion is 1.0 pm or more and 100.0 pm or less.

[0015] [5] The vapor chamber according to any one of the above [2] to [4], wherein an average value of the gap length from the occlusion portion to the opening portion in the gap flow path portion is 40.0 pm or more.

[0016] [6] The vapor chamber according to any one of the above [2] to [5], wherein the gap flow path portion has a gap expansion portion on the side of the occlusion portion, and an average value of the gap width between the top surface abutment portion and the inner surface abutment portion at the gap expansion portion is greater than an average value of the gap width at the gap flow path portion other than the gap expansion portion.

[0017] [7] The vapor chamber according to any one of the above [1] to [6], wherein a ratio (t2 / t1) of a sheet thickness t2 at the protrusion of the first metal sheet to a sheet thickness t1 at the recessed flow path of the first metal sheet is 0.1 or more and 10.0 or less.

[0018] [8] The vapor chamber according to any one of [1] to [7], wherein the protruding portion extends in a length direction of the vapor chamber.

[0019] [9] The vapor chamber according to any one of [1] to [8], wherein the vapor chamber has a plurality of the top surface engaging portions on one of the protruding portions.

[0020]

[10] The vapor chamber according to any one of [1] to [9], wherein the second metal sheet has at least one or more protruding portions on an inner surface, the protruding portion of the second metal sheet protrudes from the inner surface of the second metal sheet toward the first metal sheet, and a top surface of the protruding portion abuts against the recessed portion flow path of the first metal sheet.

[0021]

[11] A manufacturing method of a vapor chamber according to any one of [1] to

[10] , characterized by comprising a laser bonding process of forming the top surface engaging portion by laser.

[0022]

[12] The manufacturing method of a vapor chamber according to

[11] , wherein the manufacturing method further comprises a laser welding process of welding an outer edge of the first metal sheet to an outer edge of the second metal sheet by laser before or after the laser bonding process.

[0023]

[13] The manufacturing method of a vapor chamber according to

[11] or

[12] , wherein the manufacturing method further comprises a press working process of forming the recessed portion flow path and the protruding portion of the first metal sheet by press forming before the laser bonding process and the laser welding process.

[0024] Effects of the Invention

[0025] According to the present application, it is possible to provide a vapor chamber and a manufacturing method of a vapor chamber, which are excellent in mechanical strength and heat transfer characteristics. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 is a perspective view showing an example of a vapor chamber of the first embodiment.

[0027] Figure 2 is an enlarged sectional view of an A face of Figure 1 .

[0028] Figure 3 is an enlarged sectional view showing another example of a second metal sheet constituting a vapor chamber of the first embodiment.

[0029] Figure 4 is a perspective view showing another example of a protruding portion constituting a vapor chamber of the first embodiment.

[0030] Figure 5 is a perspective view showing an example of a heat spreader according to the second embodiment.

[0031] Figure 6 is an enlarged sectional view of the B face of Figure 5

[0032] Figure 7 is an enlarged sectional view showing another example of a protruding portion constituting the heat spreader according to the second embodiment. DETAILED DESCRIPTION

[0033] Hereinafter, detailed description will be made based on the embodiments.

[0034] The present inventors have made intensive studies, and as a result, have achieved improvement in mechanical strength and heat transfer characteristics by focusing on the constitution of a joint portion that joins a first metal sheet and a second metal sheet.

[0035] The heat spreader according to the embodiment has a working fluid in an internal space formed between a first metal sheet and a second metal sheet, the first metal sheet has a recess flow path provided on an inner surface thereof and at least one or more protruding portions that protrude from the inner surface of the first metal sheet toward the second metal sheet, and a top surface of the protruding portion abuts against the second metal sheet, the heat spreader has at least one or more top surface joint portions that join a part of the top surface of the protruding portion and the second metal sheet, and a gap flow path portion in which the top surface is separated from the second metal sheet.

[0036] (First Embodiment)

[0037] Figure 1 is a perspective view showing an example of a heat spreader according to the first embodiment. Figure 2 is an enlarged sectional view of the A face of Figure 1 In Figure 1 , a partially transparent state is shown for the sake of convenience in order to understand the internal structure of the heat spreader. In addition, in Figure 1 and Figure 2 , the flow direction of the working fluid F(G) in the gas phase is indicated by a solid arrow, and the flow direction of the working fluid F(L) in the liquid phase is indicated by a hollow arrow.

[0038] As Figures 1-2 ​As shown, the heat spreader 1 of the first embodiment has a first metal sheet 10 and a second metal sheet 20. The first metal sheet 10 and the second metal sheet 20 are joined such that their inner surfaces 10a and 20a face each other. That is, the interiors of the first metal sheet 10 and the second metal sheet 20 are sealed. Furthermore, the heat spreader 1 has a working fluid in the internal space S formed between the first metal sheet 10 and the second metal sheet 20. The internal space S is sealed by the first metal sheet 10 and the second metal sheet 20. The working fluid is sealed within the internal space S provided inside the heat spreader 1.

[0039] From the perspective of the cooling performance of the heat spreader 1, the working fluid sealed in the internal space S can be, for example, pure water, ethanol, methanol, acetone, etc.

[0040] The first metal sheet 10 constituting the heat spreader 1 has a recessed flow path 11 and at least one protrusion 12.

[0041] like Figure 1 As shown, a recessed flow path 11 is provided on the inner surface 10a of the first metal sheet 10. The recessed flow path 11 provided on the inner surface 10a side is recessed from the outer edge 10c of the first metal sheet 10 to the center of the inner surface 10a. For example, the recessed flow path is the space in the internal space S excluding the protrusion 12 and the gap flow path portion 14. The recessed flow path 11 is mainly used for the flow of gaseous working fluid.

[0042] The protrusion 12 protrudes from the inner surface 10a of the first metal sheet 10 toward the inner surface 20a of the second metal sheet 20. The top surface 13 of the protrusion 12 abuts against the inner surface 20a of the second metal sheet 20. For example, the protrusion 12 is a quadrangular prism.

[0043] like Figure 2 As shown, the heat spreader 1 includes at least one top surface joint 13a and a gap flow path 14.

[0044] The top surface joint 13a joins a portion of the top surface 13 of the protrusion 12 to the second metal sheet 20. In this way, in the abutment surface between the top surface 13 of the protrusion 12 and the inner surface 20a of the second metal sheet 20, the top surface joint 13a joins a portion of the top surface 13 of the protrusion 12 to a portion of the inner surface 20a of the second metal sheet 20.

[0045] In the heat exchanger 1, the heat-annealed portion 50, generated by the heat during the formation of the top surface joint 13a that joins the first metal sheet 10 and the second metal sheet 20, exists locally in the portion adjacent to the top surface joint 13a and is not formed throughout the entire heat exchanger 1. For example, as... Figure 2As shown, the vapor chamber 1 is provided with a heat-annealed portion 50 formed on the second metal sheet 20 adjacent to the top surface joint portion 13a. When observed using an SEM, the metal structure of the heat-annealed portion 50 is clearly different from the metal structure of portions other than the heat-annealed portion 50.

[0046] The first metal sheet 10 and the second metal sheet 20 are joined by the top surface joint portion 13a. The length 13ax of the top surface joint portion 13a, which joins a portion of the top surface 13 and a portion of the inner surface 20a, is smaller than the length 12x of the protruding portion 12. From the viewpoint of suppressing a decrease in the mechanical strength of the vapor chamber 1, the ratio of the length 13ax of the top surface joint portion 13a to the length 12x of the protruding portion 12 (13ax / 12x) is preferably less than 0.5. In Figure 2 In the cross section of the vapor chamber 1 including the top surface joint portion 13a, the length 13ax of the top surface joint portion 13a and the length 12x of the protruding portion 12 are distances in a direction perpendicular to the thickness direction of the vapor chamber 1.

[0047] In the gap flow path portion 14, the top surface 13 of the first metal sheet 10 is separated from the second metal sheet 20. In the gap flow path portion 14, a working fluid in a liquid phase flows.

[0048] Such a gap flow path portion 14 is provided between the top surface abutment portion 13b of the top surface 13 of the protruding portion 12 and the inner surface abutment portion 21 of the second metal sheet 20. The top surface abutment portion 13b of the first metal sheet 10 is a portion of the top surface 13 of the first metal sheet 10 that is not joined to the inner surface 20a of the second metal sheet 20. The inner surface abutment portion 21 of the second metal sheet 20 is a portion of the inner surface 20a of the second metal sheet 20 that abuts the top surface abutment portion 13b.

[0049] The top surface abutment portion 13b and the inner surface abutment portion 21 abut without being joined so as to be separable from each other. The gap flow path portion 14 is a gap that is generated due to the abutment of the top surface abutment portion 13b and the inner surface abutment portion 21. Note that, here, for convenience, a state in which the top surface abutment portion 13b and the inner surface abutment portion 21 are clearly separated is shown in order to facilitate understanding of the gap flow path portion 14.

[0050] In addition, the gap flow path portion 14 has an occlusion portion 14a on the side of the top surface joint portion 13a of the top surface abutment portion 13b. The occlusion portion 14a is a portion where the top surface abutment portion 13b is connected to the top surface joint portion 13a and is occluded by the top surface joint portion 13a. In addition, the gap flow path portion 14 has an opening portion 14b on the side of the protruding portion side surface of the top surface abutment portion 13b. The protruding portion side surface is the side surface 12a side of the protruding portion 12 and is the concave portion flow path 11 side. As such, the gap flow path portion 14 is occluded on the side of the top surface joint portion 13a of the top surface abutment portion 13b and is open on the side of the protruding portion side surface of the top surface abutment portion 13b.

[0051] A gap flow path 14 is provided on the top surface 13 side of the protrusion 12 between the recess flow path 11 and the top surface joint 13a. On the top surface 13 side of the protrusion 12, the gap flow path 14, provided around the top surface joint 13a, extends in a direction perpendicular to the thickness direction of the heat spreader 1. The gap flow path 14 is connected to the recess flow path 11 via an opening 14b. Specifically, the gap flow path 14 is connected to the recess flow path 11 on the second metal sheet 20 side.

[0052] The gap width 14w of the gap flow path 14 is much smaller than the groove spacing p of the recessed flow path 11. The gap width 14w of the gap flow path 14 is the distance between the top surface abutment portion 13b and the inner surface abutment portion 21. The groove spacing p of the recessed flow path 11 is the distance between adjacent protrusions 12 or the distance between a protrusion 12 and the outer edge 10c. As described above, the gap flow path 14 is a gap created by the abutment between the top surface abutment portion 13b and the inner surface abutment portion 21, and the gap width 14w of the gap flow path 14 is very small. Therefore, a capillary phenomenon for the working fluid of the liquid phase is generated in the gap flow path 14.

[0053] The heat spreader 1 mainly uses the following cooling path to cool the heating element 30.

[0054] Heat generated by the heating element 30, which is thermally connected to the outer surface 20b of the second metal sheet 20, is transferred to the evaporation portion 41 located on the inner surface 20a of the second metal sheet 20. For example... Figure 2 As shown, the evaporation section 41 utilizes heat transferred from the heating element 30 to evaporate the liquid working fluid flowing in the gap flow path section 14, transforming it into a gaseous working fluid as indicated by arrow F(G). The gaseous working fluid heated by evaporation is as follows: Figure 1 As indicated by arrow F(G), the working fluid flows towards the condenser 42, located separately from the evaporator 41. As the gaseous working fluid flows towards the condenser 42, its temperature decreases. In the condenser 42, the cooled gaseous working fluid is condensed and transforms into a liquid working fluid. The latent heat generated by the phase change is transferred to the first metal sheet 10 and the second metal sheet 20, and is released to the outside of the heat spreader 1. The resulting liquid working fluid is as follows... Figure 2 As indicated by arrow F(L), the liquid working fluid easily penetrates into the interstitial flow path 14 through capillary action. The liquid working fluid moves within the interstitial flow path 14 and returns to the evaporation section 41. Through this efficient circulation of the liquid and gaseous working fluids, the heat exchanger 1 can efficiently cool the heating element 30.

[0055] If the wick plate 1 has the gap flow path portion 14 on the side of the top surface 13 of the protruding portion 12, the working fluid in the liquid phase is easily immersed from the recess flow path 11 into the gap flow path portion 14 due to the capillary phenomenon of the working fluid in the liquid phase with respect to the gap flow path portion 14, and the working fluid in the liquid phase inside the gap flow path portion 14 is not easily leaked to the outside of the gap flow path portion 14. On the other hand, in the conventional wick plate which does not have the gap flow path portion 14, since a configuration equivalent to the gap flow path portion 14 of the wick plate 1 is not provided, the working fluid in the liquid phase flows in the recess flow path. In this way, compared to the conventional one, the amount of the working fluid in the liquid phase of the wick plate 1 having the gap flow path portion 14 is increased, and the amount of the working fluid returned is increased. Therefore, the amount of heat transfer in the internal space S is improved. Further, in the internal space S of the wick plate 1, the state in which the working fluid in the liquid phase is not present in the evaporation portion, so-called dryout, is suppressed, the circulation flow of the working fluid in the liquid phase and the gas phase becomes good, and the heat transfer is improved. Thus, the wick plate 1 can have excellent heat transfer characteristics.

[0056] Further, the gap flow path portion 14 easily takes in the working fluid in the liquid phase into the inside by the capillary phenomenon, and the working fluid in the liquid phase taken into the inside is not easily leaked to the outside of the gap flow path portion 14. For example, in the wick plate 1 shown in FIG. 1, even if the wick plate 1 is in an arbitrary attitude such as a state in which the wick plate 1 is inclined by 90 degrees on paper, a state in which the wick plate 1 is upside down, and the like, the working fluid in the liquid phase is easily taken into the gap flow path portion 14 and is not easily leaked to the outside from the gap flow path portion 14. In this way, regardless of the arrangement state of the wick plate 1, the circulation flow of the working fluid in the liquid phase and the gas phase is good, and thus the wick plate 1 has excellent heat transfer characteristics. Figure 1

[0057] Further, the wick plate 1 has the heat-annealed portion 50 due to heat generated when the top surface engaging portion 13a is formed, locally in the portion adjacent to the top surface engaging portion 13a, but not in the entire wick plate 1. The heat-annealed portion 50 annealed by heat treatment reduces the mechanical strength of the material. The conventional wick plate has the heat-annealed portion in a wide range of the first metal sheet and the second metal sheet, but not locally in the portion of the wick plate 1 adjacent to the top surface engaging portion 13a. In this way, compared to the conventional one, in the wick plate 1, the area of the heat-annealed portion 50 is small, and the reduction in the mechanical strength due to heat annealing can be suppressed. Therefore, the wick plate 1 can have excellent mechanical strength.

[0058] ​Further, it is preferable that the gap length 14x of the gap flow path portion 14 from the occlusion portion 14a to the opening portion 14b be longer than the gap width 14w between the top surface abutment portion 13b and the inner surface abutment portion 21. In the case of the gap flow path portion 14, if the gap length 14x is longer than the gap width 14w, the amount of working fluid in the liquid phase held in the gap flow path portion 14 increases, and the capillary phenomenon of the gap flow path portion 14 improves. Thus, the heat transport characteristics of the vapor chamber 1 are further improved.

[0059] From the viewpoint of improving the heat transport characteristics of the vapor chamber 1, it is preferable that the ratio of the gap length 14x to the gap width 14w (14x / 14w) be 1.0 or greater and 30.0 or less, and more preferable be 2.0 or greater and 10.0 or less.

[0060] Further, it is preferable that the average value of the gap width 14w of the gap flow path portion 14 be 1.0 pm or greater and 100.0 pm or less, and more preferable be 3.0 pm or greater and 50.0 pm or less, and further preferable be 5.0 pm or greater and 20.0 pm or less. If the average value of the gap width 14w is 1.0 pm or greater, the gap flow path portion 14 can be easily formed. If the average value of the gap width 14w is 100.0 pm or less, the capillary phenomenon of the gap flow path portion 14 improves, and thus the heat transport characteristics of the vapor chamber 1 are further improved.

[0061] Further, it is preferable that the average value of the gap length 14x of the gap flow path portion 14 be 40.0 pm or greater, and more preferable be 80.0 pm or greater, and further preferable be 150.0 pm or greater. Further, it is preferable that the average value of the gap length 14x be 1.0 mm or less, and more preferable be 500.0 pm or less, and further preferable be 200.0 pm or less. If the average value of the gap length 14x is 40.0 pm or greater, the amount of working fluid in the liquid phase held in the gap flow path portion 14 increases, and the capillary phenomenon of the gap flow path portion 14 improves, and thus the heat transport characteristics of the vapor chamber 1 are further improved. If the average value of the gap length 14x is 1.0 mm or less, the gap flow path portion 14 can be easily formed.

[0062] Further, as Figure 2As shown, the gap flow path portion 14 has a gap expansion portion 15 on the side of the occlusion portion 14a, and preferably the average of the gap width 15w between the top surface abutment portion 13b and the inner surface abutment portion 21 at the gap expansion portion 15 is greater than the average of the gap width 14w between the top surface abutment portion 13b and the inner surface abutment portion 21 at the gap flow path portion 14 other than the gap expansion portion 15. If the average of the gap width 15w at the gap expansion portion 15 is greater than the average of the gap width 14w between the top surface abutment portion 13b and the inner surface abutment portion 21 at the gap flow path portion 14 other than the gap expansion portion 15, the amount of working fluid in the liquid phase in the gap flow path portion 14 and the gap expansion portion 15 increases, and the capillary phenomenon of the gap flow path portion 14 improves. Thus, the heat transport characteristics of the vapor chamber 1 are further improved.

[0063] From the viewpoint of improving the heat transport characteristics of the vapor chamber 1, preferably the ratio of the gap width 15w to the gap width 14w (15w / 14w) is 1.1 or greater and 2.0 or less. If the ratio (15w / 14w) is 1.1 or greater, the heat transport characteristics of the vapor chamber 1 improve. If the ratio (15w / 14w) is 2.0 or less, the gap expansion portion 15 can be easily formed.

[0064] In addition, from the viewpoint of improving the heat transport characteristics of the vapor chamber 1, as shown in Figure 2 Preferably, the gap expansion portion 15 is provided in the portion of the top surface abutment portion 13b closest to the top surface joint portion 13a, in other words, at the occlusion portion 14a. Similarly, from the viewpoint of improving the heat transport characteristics of the vapor chamber 1, preferably the shape of the gap expansion portion 15 is spherical as shown in Figure 2

[0065] In addition, as shown in Figure 1 Preferably, the protrusion portion 12 extends in the length direction L1 of the vapor chamber 1. If the protrusion portion 12 extends in the length direction L1 of the vapor chamber 1, the distance from the evaporation portion 41 to the condensation portion 42 increases, and the amount of working fluid returning increases. Thus, the heat transport characteristics of the vapor chamber 1 are further improved.

[0066] In addition, preferably the vapor chamber 1 has a plurality of top surface joint portions 13a at one of the protrusion portions 12. If a plurality of top surface joint portions 13a are provided at one protrusion portion 12, the bonding force of the first metal sheet 10 and the second metal sheet 20 improves. If a plurality of top surface joint portions 13a are provided at each protrusion portion 12, the bonding force of the first metal sheet 10 and the second metal sheet 20 further improves.

[0067] Figure 3 is an enlarged cross-sectional view showing another example of the second metal sheet 20 constituting the vapor chamber 1. As shown in Figure 3 ​As shown, the second metal sheet 20 preferably has at least one or more protrusions 22 on the inner surface 20a, and the protrusions 22 of the second metal sheet 20 protrude from the inner surface 20a of the second metal sheet 20 toward the first metal sheet 10, and the top surface 23 of the protrusions 22 abuts the recessed flow path 11 of the first metal sheet 10.

[0068] The top surface 23 of the protrusions 22 of the second metal sheet 20 abuts the recessed flow path 11, i.e., the inner surface 10a of the first metal sheet 10. Thus, the mechanical strength of the vapor chamber 1 in the thickness direction is further improved. In addition, a gap is provided between the top surface 23 of the protrusions 22 and the inner surface 10a of the first metal sheet 10, which is formed by the abutment. This gap, like the gap flow path portion 14, generates a capillary phenomenon for the working fluid in the liquid phase, and thus the working fluid in the liquid phase is easily taken in. Thus, the heat transfer characteristics of the vapor chamber 1 are further improved.

[0069] In addition, the inner surface 10a of the first metal sheet 10 and the inner surface 20a of the second metal sheet 20 preferably have a roughened structure or a groove structure. The roughened structure is formed by roughening processing of the inner surfaces 10a and 20a. If the inner surfaces 10a and 20a have a roughened structure or a groove structure, the working fluid in the liquid phase easily flows along these structures, and the circulation of the working fluid in the liquid phase and the gas phase is good. Thus, the heat transfer characteristics of the vapor chamber 1 are further improved.

[0070] In the formation of the top surface joint portion 13a and the gap flow path portion 14 and the partial formation of the heat annealed portion 50 described above, which improve the heat transfer characteristics of the vapor chamber 1, processing using a laser is preferable, and more preferably processing using a fiber laser. In the processing using a laser, the formation of the heat annealed portion 50 can be suppressed from expanding, and the top surface joint portion 13a and the gap flow path portion 14 can be formed in a desired shape in a short time. As a result, the heat annealed portion 50 is partially formed in the vapor chamber 1 rather than being formed over a large area. On the other hand, in the joining of the first metal sheet and the second metal sheet using diffusion bonding, which is employed in the conventional vapor chamber, it is difficult to form the top surface joint portion 13a and the gap flow path portion 14, particularly the gap flow path portion 14, and the heat annealed portion or the like is formed over the entire vapor chamber, and the processability is very low compared to the laser processing.

[0071] In addition, as the material constituting the first metal sheet 10 and the second metal sheet 20, copper, copper alloy, aluminum, aluminum alloy, and stainless steel are preferable from the viewpoints of high thermal conductivity, ease of processing using a laser, and the like. Among these, aluminum and aluminum alloy are more preferable in order to achieve weight reduction, and stainless steel is more preferable in order to improve the mechanical strength. In addition, depending on the use environment, tin, tin alloy, titanium, titanium alloy, nickel, and nickel alloy can also be used for the first metal sheet 10 and the second metal sheet 20.

[0072] The heat generating body 30 assembled to the vapor chamber 1 is a component such as an electronic component that generates heat during operation.

[0073] Next, the manufacturing method of the vapor chamber 1 described above will be explained.

[0074] The manufacturing method of the vapor chamber 1 has a laser joining process of forming the top surface joining portion 13a by laser. In the laser joining process, it is preferable to form the top surface joining portion 13a joining the first metal sheet 10 and the second metal sheet 20 by fiber laser. In laser processing, it is easy to process control the top surface joining portion 13a to a desired shape, and the top surface joining portion 13a can be formed in a short time. Further, since laser processing enables local heating of the portion to be joined, a heat annealing portion 50 due to heating is locally formed in the portion adjacent to the top surface joining portion 13a, and does not form in a wide range in the vapor chamber 1. In laser, the process control and short-time processing of fiber laser are more excellent. If the top surface joining portion 13a is formed, the gap flow path portion 14 is also formed as a result. Since the process of mounting the conventional capillary structure (wick structure) separately is not required, it is possible to reduce the manufacturing cost and manufacturing time, and to achieve ease of manufacturing.

[0075] Specifically, the inner surface 10a of the first metal sheet 10 having the recess flow path 11 and the protruding portion 12 and the inner surface 20a of the second metal sheet 20 are opposed to each other, and laser is irradiated to a part of the top surface 13 in a state where the top surface 13 of the protruding portion 12 of the first metal sheet 10 and the inner surface 20a of the second metal sheet 20 are in contact. For example, laser can be irradiated to a part of the top surface 13 from the first metal sheet 10 side, laser can be irradiated to a part of the top surface 13 from the second metal sheet 20 side, or the above laser irradiation combinations can be used.

[0076] On the other hand, in joining such as diffusion joining employed in the conventional vapor chamber, the first metal sheet and the second metal sheet are heat treated as a whole. In such heat treatment, since the entire top surface 13 of the protruding portion 12 is joined to the inner surface of the second metal sheet 20, it is difficult to form the top surface joining portion 13a and the gap flow path portion 14 as such. Therefore, in addition to the process of joining the first metal sheet and the second metal sheet, a process of separately providing the capillary structure is required. Further, since the first metal sheet and the second metal sheet are heat treated as a whole to be heat annealed, the mechanical strength of the vapor chamber is reduced.

[0077] Furthermore, the preferred method for manufacturing the heat spreader 1 includes a laser welding process, either before or after the laser bonding process, in which the outer edge 10c of the first metal sheet 10 is welded to the outer edge 20c of the second metal sheet 20 using a laser. By welding the outer edge 10c of the first metal sheet 10 to the outer edge 20c of the second metal sheet 20 using a laser, a welded portion 51 is formed, making it easy to manufacture the heat spreader 1, which has an internal space S. If the laser used in the laser bonding process is the same as the laser used in the laser welding process, the heat spreader can be manufactured more easily and in a shorter time.

[0078] Specifically, the inner surface 10a of the first metal sheet 10 and the inner surface 20a of the second metal sheet 20 are positioned opposite each other, and laser light is irradiated onto the first metal sheet 10 and the second metal sheet 20 in a state where the outer edge 10c of the first metal sheet 10 is in contact with the outer edge 20c of the second metal sheet 20. For example, laser light can be irradiated from the first metal sheet 10 side toward the contact portion of the outer edge 10c and the outer edge 20c, or from the second metal sheet 20 side toward the contact portion of the outer edge 10c and the outer edge 20c, or from the in-plane direction of the heat spreader 1 toward the contact portion of the outer edge 10c and the outer edge 20c, or a combination of the above-mentioned laser irradiation methods can be used.

[0079] The heat spreader 1 manufactured in this way is suitable for electronic devices such as mobile phones that require good heat transfer characteristics under various postures. Electronic devices equipped with the heat spreader 1 exhibit the high heat transfer characteristics of the heat spreader 1 under various usage conditions.

[0080] According to the embodiments described above, the liquid working fluid easily penetrates and flows into the gap flow path, thus improving the circulation of both the liquid and gaseous working fluids and increasing heat transfer within the internal space of the heat spreader. Therefore, the heat spreader can possess excellent heat transfer characteristics. Furthermore, the heat spreader has heat-annealed sections locally, rather than throughout the entire surface. Therefore, the reduction in mechanical strength of the heat spreader caused by the heat-annealed sections can be suppressed.

[0081] It should be noted that the above explanation is as follows: Figure 1 The example shown is that the heating element 30 is mounted on the outer surface 20b of the second metal sheet 20, but the heating element 30 can also be mounted on the outer surface 10b of the first metal sheet 10.

[0082] In addition, it is preferable to arrange the heat spreader 1 in a manner that the second metal sheet 20 is arranged on the side in the direction of gravity, that is, the second metal sheet 20 is arranged below and the first metal sheet 10 is arranged above along the direction of gravity. If the heat spreader 1 is arranged in a manner that the second metal sheet 20 is arranged on the side in the direction of gravity, the gap flow path portion 14 is arranged on the side in the direction of gravity in the internal space S. The working fluid in the liquid phase is affected by the gravity in addition to the capillary phenomenon of the gap flow path portion 14, and becomes easy to enter the gap flow path portion 14. As a result, the heat transport characteristics of the heat spreader are further improved. If the heat generating body 30 is mounted to the outer surface 20b of the second metal sheet 20, that is, the lower portion of the heat spreader 1 in the arrangement state of such a heat spreader, the heat generating body 30 can be efficiently cooled.

[0083] In addition, the above describes an example in which the protrusion 12 is a quadrangular prism shape, but the shape of the protrusion 12 can be such that the top surface 13 abuts against the inner surface 20a of the second metal sheet 20. For example, the shape of the protrusion 12 can be a cylindrical shape as shown in FIG. 6B. Figure 1 Figure 4 In addition, in a case where the first metal sheet 10 has a plurality of protrusions 12, the shapes of the protrusions 12 can be the same or at least a part of them can be different.

[0084] (Second Embodiment)

[0085] Figure 5 is a perspective view showing an example of the heat spreader of the second embodiment. Figure 6 is an enlarged sectional view of the B face of Figure 5

[0086] Note that in the embodiments shown below, the same reference numerals are assigned to the same constituent parts as those of the heat spreader of the first embodiment, and the repeated explanation is omitted or simplified.

[0087] In the heat spreader 2 of the second embodiment, the constitution is basically the same as that of the heat spreader 1 of the first embodiment except for the constitution of the first metal sheet 10. Therefore, the following mainly explains the different constitution.

[0088] As shown in FIG. 6A, the first metal sheet 10 of the heat spreader 2 has a higher uniformity of sheet thickness than the first metal sheet 10 of the heat spreader 1 of the first embodiment. Figures 5-6 Figure 2 As shown in FIG. 6A, the sheet thickness at the protrusion 12 is significantly larger than the sheet thickness at the recess flow path 11 in the first metal sheet 10 of the heat spreader 1.

[0089] As shown in FIG. 6A, the sheet thickness at the protrusion 12 is significantly larger than the sheet thickness at the recess flow path 11 in the first metal sheet 10 of the heat spreader 1. Figure 6 ​​​As shown, in the heat spreader 2, the ratio (t2 / t1) of the sheet thickness t2 at the protrusion 12 of the first metal sheet 10 to the sheet thickness t1 at the recessed flow path 11 of the first metal sheet 10 is preferably 0.1 or more and 10.0 or less, more preferably 0.2 or more and 5.0 or less, even more preferably 0.5 or more and 2.0 or less, and most preferably 1.0, that is, the sheet thickness t1 at the recessed flow path 11 is the same as the sheet thickness t2 at the protrusion 12.

[0090] If the ratio (t2 / t1) is within the above range, the deviation in the sheet thickness of the first metal sheet 10 can be suppressed, thus enabling the heat spreader 2 to be lightweight. The formation of the first metal sheet 10 having such a specified ratio (t2 / t1) is preferably based on a stamping process.

[0091] Figure 7 This is an enlarged cross-sectional view showing other examples of the protrusion 12 constituting the heat spreader 2. For example... Figure 7 As shown, the first metal sheet 10 may further have a protrusion 16 protruding from a portion of its top surface 13 toward the inner surface 20a of the second metal sheet 20. The top surface of the protrusion 16, which is located on a portion of the top surface 13 of the protrusion 12, engages with the inner surface 20a of the second metal sheet 20. In this case, either a portion of the top surface of the protrusion 16 can engage with the inner surface 20a of the second metal sheet 20, or the entire top surface of the protrusion 16 can engage with the inner surface 20a of the second metal sheet 20. The protrusion 16 is preferably formed based on a stamping process.

[0092] If the heat spreader 2 has the protrusion 16, the shape of the gap flow path 14 can be easily controlled, thus facilitating the intake of the liquid working fluid into the gap flow path 14. Therefore, the heat transfer characteristics of the heat spreader can be improved. Furthermore, it is easier to make the contact area between the top surface of the protrusion 16 and the inner surface 20a of the second metal sheet 20 smaller than the contact area between the top surface joint 13a and the inner surface 20a of the second metal sheet 20 in a heat spreader without the protrusion 16, allowing for further localization of the heat-annealed section 50. Therefore, the reduction in the mechanical strength of the heat spreader caused by the heat-annealed section can be further suppressed.

[0093] Next, the manufacturing method of the above-mentioned heat spreader 2 will be explained.

[0094] The preferred method for manufacturing the heat spreader 2 further includes a stamping process, prior to the aforementioned laser bonding and laser welding processes, a stamping process to form the recessed flow path 11 and protrusion 12 of the first metal sheet 10 by stamping. By stamping the first metal sheet 10, the recessed flow path 11 and protrusion 12 can be easily formed. More preferably, in the stamping process, in addition to forming the recessed flow path 11 and protrusion 12 on the first metal sheet 10, a convex portion 16 is also formed.

[0095] By performing the laser welding process after the press working process followed by the laser joining process, or performing the laser joining process after the laser welding process, the vapor chamber 2 can be manufactured.

[0096] According to the above-described embodiment, by reducing the deviation in the sheet thickness of the first metal sheet, the vapor chamber can be made lightweight. Such recess flow paths and protrusions of the first metal sheet can be easily formed by press molding in a short time. Therefore, the vapor chamber can be manufactured more easily.

[0097] The above-described embodiment has been described, but the present application is not limited to the above-described embodiment, but includes all modes included in the concept and claims of the present application, and various changes can be made within the scope of the present application.

[0098] Explanation of Reference Signs

[0099] 1, 2 Vapor chamber

[0100] 10 First metal sheet

[0101] 10a Inner surface of the first metal sheet

[0102] 10b Outer surface of the first metal sheet

[0103] 10c Outer edge of the first metal sheet

[0104] 11 Recess flow path

[0105] 12 Protrusion

[0106] 12a Side surface of the protrusion

[0107] 13 Top surface of the protrusion

[0108] 13a Top surface joining portion

[0109] 13b Top surface abutting portion

[0110] 14 Gap flow path portion

[0111] 14a Occlusion portion of the gap flow path portion

[0112] 14b Opening portion of the gap flow path portion

[0113] 15 Gap expansion portion

[0114] 16 Convex portion

[0115] 20 Second metal sheet

[0116] 20a Inner surface of the second metal sheet

[0117] 20b outer surface of the second metal sheet

[0118] 20c outer edge of the second metal sheet

[0119] 21 inner surface abutment portion

[0120] 22 protrusion

[0121] 23 top surface of the protrusion

[0122] 30 heat generating body

[0123] 41 evaporation section

[0124] 42 condensation section

[0125] 50 thermal annealing section

[0126] 51 welding section

[0127] S internal space

[0128] F(L) flow of working fluid in liquid phase

[0129] F(G) flow of working fluid in gas phase

Claims

1. A vapor chamber having a working fluid in an internal space formed between a first metal sheet and a second metal sheet, the vapor chamber characterized by, the first metal sheet has a recess flow path and at least one or more protrusions, the recess flow path is provided to an inner surface of the first metal sheet, the protrusion protrudes from the inner surface of the first metal sheet toward the second metal sheet, and a top surface of the protrusion abuts the second metal sheet, the vapor chamber has at least one or more top surface joint portions and a gap flow path portion, the top surface joint portion joins a portion of the top surface of the protrusion and the second metal sheet, in the gap flow path portion, the top surface is separated from the second metal sheet, the gap flow path portion is provided between a top surface abutment portion, which is not joined with the second metal sheet, in the top surface of the first metal sheet and an inner surface abutment portion, which abuts the top surface abutment portion, in the second metal sheet, has an occlusion portion on the side of the top surface joint portion of the top surface abutment portion, and has an opening portion on the side of the protrusion of the top surface abutment portion.

2. The vapor chamber of claim 1, wherein, In the gap flow path portion, a gap length from the occlusion portion to the opening portion is longer than a gap width between the top surface abutment portion and the inner surface abutment portion.

3. The vapor chamber of claim 1 or 2, wherein In the gap flow path portion, an average value of the gap width between the top surface abutment portion and the inner surface abutment portion is 1.0 μm or more and 100.0 μm or less.

4. The vapor chamber of claim 1 or 2, wherein In the gap flow path portion, an average value of the gap length from the occlusion portion to the opening portion is 40.0 μm or more.

5. The vapor chamber of claim 1 or 2, wherein The gap flow path portion has a gap expansion portion on the side of the occlusion portion, an average value of the gap width between the top surface abutment portion and the inner surface abutment portion at the gap expansion portion is greater than an average value of the gap width at the gap flow path portion other than the gap expansion portion.

6. The vapor chamber of claim 1 or 2, wherein A ratio (t2 / t1) of a sheet thickness t2 at the protrusion of the first metal sheet with respect to a sheet thickness t1 at the recess flow path of the first metal sheet is 0.1 or more and 10.0 or less.

7. The vapor chamber of claim 1 or 2, wherein The protrusion extends in a length direction of the vapor chamber.

8. The vapor chamber of claim 1 or 2, wherein The vapor chamber has a plurality of the top surface joint portions on one of the protrusions.

9. The vapor chamber of claim 1 or 2, wherein, The second metal sheet has at least one or more protrusions on an inner surface, the protrusion of the second metal sheet protrudes from the inner surface of the second metal sheet toward the first metal sheet, and a top surface of the protrusion abuts the recess flow path of the first metal sheet.

10. A manufacturing method of a vapor chamber, the manufacturing method of the vapor chamber being described in any one of claims 1 to 9, the manufacturing method characterized by, having a laser joint process of forming the top surface joint portion with a laser.

11. The method of manufacturing a vapor chamber according to claim 10, wherein further having, before or after the laser joint process, a laser welding process of welding an outer edge of the first metal sheet and an outer edge of the second metal sheet with a laser.

12. The method of manufacturing a vapor chamber according to claim 10 or 11, wherein The laser joining process and the laser welding process are preceded by a press working process of forming the recessed channel and the protruding portion of the first metal sheet by press forming. The laser joining process and the laser welding process are preceded by a press working process of forming the recessed channel and the protruding portion of the first metal sheet by press forming.

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