JP2010238858A - Heat transporter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide at low cost a heat transporter having high heat exhaust efficiency. <P>SOLUTION: The present invention relates to a heat transporter 10 which is interposed between a heating part 1 and a radiating part 2 for radiating heat generated by the heating part 1. The heat transporter 10 includes a base 11 and a plurality of bristles 12, having a hollow part H, provided approximately vertically on a surface of the base 11 opposed to the heating object 1 and/or the radiating part 2. The main component of the base 11 and the plurality of bristles 12 is Cu and they are formed by plating. A distal end of the base 11 or of each of the plurality of bristles 12 is directly abutted to the heating object 1 and the radiating part 2 and in the base 11 or the plurality of bristles 12 abutted to at least either the heating object 1 or the radiating part 2, a cavity that the base 11 has or a cavity among the plurality of bristles 12 is filled with a filling 13 comprised of a resin, solder or brazing material containing high heat conductivity fillers. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention provides an electronic device equipped with an electronic component having an IC chip serving as a heat generation source, such as a TV, a projector, a computer, an inverter device, etc., and a heat dissipation portion for cooling the heat generation portion. The present invention relates to a heat transporter that improves heat conduction.

  Conventionally, various methods for releasing heat generated from electronic devices such as televisions, projector elements, and CPUs of personal computers have been studied. As for computers, desktop computers, notebook computers, servers, large mainframe computers, etc., process large volumes of information at high speed. Therefore, an increase in the number of clocks is required. Along with this, the amount of heat generated by the MPU tends to increase year by year.

  However, the current situation is that exhaust heat technology has not caught up with the rate of increase in the amount of heat generated. Therefore, since the MPU element malfunctions due to its own heat generation, there is a situation in which development for increasing the number of clocks has to be temporarily stopped, and the need for a more efficient exhaust heat technology is increasing.

  In desktop personal computers, servers, and the like, MPU cooling is performed based on air cooling technology that is substantially the same as element cooling technology for rear-pro televisions and projectors. That is, heat is transmitted to an aluminum (Al) heat sink through a heat conductive sheet or heat conductive resin provided on the back of the MPU, and air is radiated to the atmosphere by applying air from the back with a fan. Alternatively, heat is carried from the MPU to the vicinity of the casing using a heat pipe, and the heat is exhausted outside the casing by a heat sink and a fan provided with large radiating fins.

  As a recent cooling technique in the field of such an air cooling technique, Patent Document 1 (Japanese Patent Application Laid-Open No. 2004-319942) discloses a heat sink using a metal foam for a heat radiating portion. Patent Document 2 (Japanese Patent Laid-Open No. 2005-032881) discloses a porous heat dissipating body having a low porosity portion and a high porosity portion.

JP 2004-319942 A JP 2005-032881 A

  However, since the metal foam shown in Patent Document 1 has innumerable pores inside, rather than obtaining heat dissipation characteristics if the usage method is mistaken, such as polystyrene foam having high heat insulation performance due to the internal pores. There is a risk of acting as a heat insulating layer. Moreover, since the convex structure part of patent document 2 does not deform | transform so that a porous sintered compact and ceramic fiber may be enumerated as an example, it is difficult to make it contact with a thermal radiation part directly without gap.

  On the other hand, the problem of the low cooling efficiency of the air cooling technology still remains, and the current situation is that the heat radiation cannot catch up more and more as the heat generation amount of the MPU increases. In addition, since heat pipes are only devices that carry heat, air cooling technology is necessary in that heat must be dissipated to the atmosphere by a heat sink and fan with large radiating fins and discharged to the outside of the housing. It is substantially the same as that, and rather, the adoption of a heat pipe has hindered miniaturization.

  As a method for solving this problem, for example, as described in JP-A-2007-273930, a plurality of columnar bodies are formed of a material having excellent thermal conductivity such as Cu, and the plurality of columnar bodies are formed. It has been proposed to transfer heat to cooling parts. This eliminates to some extent the problem of thermal resistance in gaps due to swell and surface roughness of packages containing ceramic substrates and IC chips, without using polymer or organic sheets or grease. It became possible.

  However, when a plurality of columnar bodies are formed by electrical discharge machining or the like from a material having excellent thermal conductivity such as Cu, the rigidity of the columnar bodies becomes too high, and undulation and surface roughness are usually caused by the mounting pressure normally allowed for electronic devices. The tip of the multiple columnar bodies cannot be completely aligned with the heat generating part or the heat radiating part, and some of the columnar parts cannot contact the heat generating part or the heat radiating part, and the cooling capacity of the entire columnar body is sufficient. Could not be demonstrated. Furthermore, the columnar body has a high manufacturing cost and has been an obstacle to practical use.

  In view of such a conventional situation, the present invention does not use a polymer or an organic sheet or grease, and does not generate a gap serving as a thermal resistance, and does not generate a heat generating part (cooled body) such as ceramics or heat dissipation. The heat transferred from the object to be cooled can be immediately dissipated to the refrigerant and the heat radiating part. Therefore, heat sinks and heat radiating fins using conventional polymer and organic sheets and grease can be installed. An object of the present invention is to provide a new heat transporter having higher exhaust heat efficiency than a cooling means such as a heat sink and a fan provided at a low cost.

  In order to achieve the above object, the heat transporter provided by the present invention is a heat transporter interposed between a heat generating part provided with an electronic component such as an IC chip and a heat dissipating part that dissipates heat generated in the heat generating part. A base portion and a plurality of hair bodies having a hollow portion provided substantially vertically on a surface facing the heating element and / or the heat dissipation portion of the base portion, and the base portion and The plurality of hairs are mainly composed of Cu and formed by plating, and either the base portion or the tips of the plurality of hairs are in direct contact with the heating element and the heat dissipation part, and the heat generation The base part or the plurality of hairs that contact at least one of the body and the heat radiating part is characterized in that a filler is buried in a space part of the base part or a space part between the plurality of hairs. Yes.

  In the heat transport body of the present invention, the filler is a resin containing at least one selected from the group consisting of metal, ceramic, and carbon as a high thermal conductive filler, or a solder or brazing material. It is preferable.

  According to the present invention, the heat-generating part such as an IC chip or a package containing the IC chip and / or a heat-radiating part such as a heat sink provided with heat-dissipating fins directly contact with the deformable hairs, The heat generated in the heat generating part can be efficiently transmitted to the heat radiating part.

It is a schematic sectional drawing which shows a mode that the heat transport body of one Embodiment of this invention is interposed between the heat-emitting part and the thermal radiation part. It is general | schematic sectional drawing which shows a mode that the heat transport body of the other embodiment of this invention is interposed between the heat-emitting part and the thermal radiation part. It is a partial expanded sectional view which shows typically the hair body which the heat transport body of this invention comprises. It is a partial expanded sectional view which shows typically the fiber to which the raising | fluff used suitably used when manufacturing the hair body which the heat transport body of this invention comprises is given. It is a schematic diagram which shows a mode that the hair body which the heat transport body of this invention comprises with respect to the heat generating part which has an unevenness | corrugation. It is a schematic sectional drawing which shows the heat transport body of the comparative example 1 interposed between the heat-emitting part and the heat radiating part. It is a partial expanded sectional view which shows a mode that the columnar body which the heat transport body of FIG. 5 comprises, and the heat generating part are mutually contacting. It is general | schematic sectional drawing which shows the heat transport body of the comparative example 2 currently interposed between the heat-emitting part and the thermal radiation part. It is general | schematic sectional drawing which shows the heat transport body of the comparative example 3 currently interposed between the heat-emitting part and a thermal radiation part.

  Hereinafter, embodiments of the heat transporter of the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing a specific example of the heat transporter 10 of the present invention. This heat transporter 10 is interposed between a heat generating part 1 such as an IC chip or a package containing the IC chip and a heat radiating part 2 such as a heat sink for radiating heat generated in the heat generating part 1. It plays a role of transmitting the generated heat to the heat radiating section 2. The heat transport body 10 includes a substantially flat base 11 having Cu as a main component and a plurality of elongated hairs 12 having Cu as a main component.

  The plurality of hair bodies 12 are provided substantially vertically on the upper surface of the base portion 11, that is, on the surface of the base portion 11 that faces the heating element 1. Thereby, each front-end | tip part of the several hair body 12 contact | abuts from the substantially perpendicular | vertical direction to the lower surface of the heat generating part 1, and the lower surface of the base | substrate part 11 contact | abuts directly to the upper surface of the thermal radiation part 2. Therefore, the heat generated in the heat generating part 1 is transmitted to the heat radiating part 2 through the plurality of hairs 12 and the base part 11 connected thereto. In addition, although the six hair bodies 12 are shown in the heat transport body 10 of FIG. 1, it is not limited to this number.

  In the specific example shown in FIG. 1, the plurality of hair bodies 12 are provided only on the upper surface of the base portion 11. However, the present invention is not limited to this, and the plurality of hair bodies 12 are provided only on the lower surface of the base portion 11. It may be provided. Alternatively, as in another specific example of the present invention shown in FIG. When the plurality of hair bodies 12 are provided on both upper and lower surfaces of the base portion 11, the heat transport body 10 can be made more excellent in deformability than when provided on only one side.

  When the heat transport body 10 is interposed between the heat generating portion 1 such as an IC chip or a package containing the IC chip and the heat radiating portion 2 such as a heat sink, the heat generating portion 1 or the heat radiating portion 2 with which the heat transport body 10 abuts. The warpage and waviness that are normally present on the abutment surface must be taken into account. As for the size of these warps and waviness, for example, the height difference between the highest convex portion and the lowest concave portion may be relatively large as about 100 to 300 μm.

  In the heat transport body 10 of the present invention, as described above, the portions that contact the heat generating portion 1 and the heat radiating portion 2 are formed by the plurality of hair bodies 12, so that they are softer than conventional protrusions and rod-shaped bodies. can do. Therefore, the hair 12 can be easily deformed with a normal pressing pressure applied when the IC chip or the heat sink is attached. Thus, since the hair-like body 12 is rich in deformability, almost all the tips of the hair-like bodies 12 are brought into contact with the contact surfaces of the heat-generating portion 1 and the heat-dissipating portion 2 having warpage and undulation. Thus, a large contact area can be obtained as a whole of the plurality of hairs 12. Therefore, the heat transport capability of the heat transporter 10 can be increased.

  By the way, since the heat generating part 1 such as an IC chip or a package containing the IC chip and the heat radiating part 2 such as a heat sink are generally formed of different materials, their thermal expansion coefficients are often different. . For example, when the heat generating portion 1 is ceramic and the heat radiating portion 2 is Al, the difference in thermal expansion becomes large, and if these are integrally joined by soldering or the like, they are easily damaged by the difference in thermal expansion. Moreover, even if a general-purpose heat conductive sheet is interposed between them, the contact state gradually deteriorates due to the heat cycle and expansion and contraction due to the difference in thermal expansion, and the heat transport capability deteriorates with time.

  In contrast, the hair 12 elastically contacts the heat generating part 1 and the heat radiating part 2 by its own deformability, so that stress is generated in the heat generating part 1 and the heat radiating part 2 even if a difference in thermal expansion occurs. The thermal contact can be maintained without causing it. Therefore, the crack by a thermal expansion difference can be prevented. In addition, since the heat cycle can be followed by its own deformability, the initial heat transport capability can be maintained.

  Furthermore, in the heat transport body 10 of the present invention, as shown in FIG. 3, each hair body 12 has a hollow portion (cavity) H therein. That is, each hair body 12 has a hollow structure except for a portion that contacts the heat generating portion 1 and the heat radiating portion 2. Thereby, in the ciliary body 12, a deformability can be improved, ensuring the contact area with the heat-emitting part 1 and the heat radiating part 2 favorably. Therefore, it becomes possible to uniformly contact the hair 12 with the contact surfaces of the heat generating portion 1 and the heat radiating portion 2 that are locally inclined at various angles due to warping and undulation, It can be efficiently transmitted to the heat radiating part 2 such as a heat sink.

  The base part 11 and the hair-like body 12 are made of Cu, which is a high heat conductive material. Since Cu has a relatively high thermal conductivity of about 400 W / mK, the heat of the heat generating portion 1 can be efficiently transferred to the heat radiating portion 2 such as a heat sink. In addition, since Cu is relatively flexible among metals, forming the hair-like body 12 with a material containing Cu as a main component facilitates plastic deformation. This is preferable because the contact area can be increased and heat can be efficiently transferred. Gold and silver also have high thermal conductivity and deformability, but these materials are quite expensive and are not preferable from an industrial viewpoint.

  It is preferable that the hair-like body 12 comes into contact with the heating element 1 and / or the heat radiating portion 2 from a substantially vertical direction. This is because if the contact direction is horizontal, heat cannot be efficiently transferred from the heat generating portion 1 to the heat radiating portion 2. Moreover, since the extending direction of each ciliary body 12 and the direction of heat transfer become substantially the same by abutting from a substantially vertical direction, the heat transfer distance is the shortest, so that heat can be efficiently transported.

  With the above structure, any of the plurality of hair bodies 12 or the base portion 11 connected thereto directly contacts the heat generating portion 1 and the heat radiating portion 2. The base portion 11 or the plurality of hair bodies 12 that are in contact with each other are filled with a filler 13 such as a resin containing a high thermal conductive filler in a space portion of the base portion 11 or a space portion between the plurality of hair bodies 12. . By partially filling these voids with the filler 13, the heat conduction efficiency can be increased compared to the case where the voids remain air, the contact thermal resistance is reduced, and the heat transport capability is further improved. be able to.

  For example, as shown in FIG. 1, when the hair body 12 is erected only on one surface of the base portion 11, the hair body 12 is brought into direct contact with the heat generating portion 1, and the heat radiation portion 2 is connected to the hair body 12. The base part 11 is brought into direct contact to form a heat path as a heat transfer path, and a filler 13 (not shown) made of a resin with a high thermal conductivity filler is buried in the gap part of the base part 11.

  Thereby, since the base part 11 can be closely_contact | adhered with a wider contact area with respect to the heat radiating part 2 at the same time, while the some hair-like body 12 which has elasticity contact | abuts to the heat-emitting part 1, several hair-like bodies 12 and In the heat path formed by the base portion 11, a good contact state can be maintained while following the expansion and contraction of the member due to the heat cycle. Furthermore, it is possible to follow a difference in thermal expansion between different materials of the heat generating portion 1 and the heat radiating portion 2.

  As the material of the filler 13, solder or brazing material can be used in addition to the resin containing the high thermal conductive filler. Solder or brazing is preferable because it has higher thermal conductivity than resin and can reduce thermal resistance. In addition, since many resins have a heat-resistant temperature up to about 200 ° C., soldering or brazing is preferable when the temperature is 200 ° C. or higher. Which material to select for the filler 13 can be appropriately selected according to the operating temperature of the member and the difference in thermal expansion.

  In general, the ceramic used for the heat generating part 1 and Al used for the heat radiating part 2 have greatly different coefficients of thermal expansion, and if they are joined directly by soldering or brazing without interposing anything between them, the thermal resistance is reduced. Although it can be reduced, direct bonding is not possible because the ceramic is cracked by the heat cycle. On the other hand, it is possible to reduce the thermal resistance without causing cracks due to heat cycle by embedding solder or brazing material in the gaps between the plurality of hairs 12 or the gaps of the base part 11 itself. it can.

  Further, the gap between the base 11 and the gap between the plurality of hairs 12 may be filled with the filler 13 to connect the heat generating part 1 and the heat radiating part 2. Even in this case, since the hair 12 still has deformability, no thermal stress is generated even if the materials of the heat generating portion 1 and the heat radiating portion 2 are different. When the plurality of hair bodies 12 are provided on both surfaces of the base portion 11, as shown in FIG. 2, the hair bodies 12 and the base portion 11 provided on one surface are filled with the filler 13, The hair 12 provided on the other surface may not be filled with the filler 13.

  In order to efficiently bring the plurality of hairs 12 into contact with the heat generating part 1 and the heat radiation part 2, it is preferable to arrange the plurality of hairs 12 substantially uniformly at a predetermined height. Accordingly, the plurality of hairs 12 can be individually deformed and uniformly contacted with the heat generating portion 1 and the heat radiating portion 2 that are actually warped or wavy. For example, as shown in FIG. 5, the plurality of hairs 12 provided on the surface of the base 11 facing the heat generating part 1 are provided in a region facing the recess of the heat generating part 1. Even when the hair 12a is hardly bent or curved, the hair 12b is gently bent, and the hair 12b provided in the region facing the convex portion of the heat generating portion 1 is greatly curved. Thereby, all the ciliary bodies can contact the heat generating part 1 reliably.

  Thus, in order to give the capillaries 12 deformability, it is possible to reduce the diameter of each capillaries 12 or increase the length of each capillaries 12 to some extent. However, if the diameter of the hair-like body 12 is too small, the contact area with the heat generating part 1 is reduced, and it is difficult to efficiently transfer heat. Moreover, when the length of the hair-like body 12 is too long, the heat transfer path becomes long, and as a result, the thermal resistance increases as a whole.

  Specifically, the length (distance indicated by L in FIG. 3) of the hairs 12 that conduct heat is 0.2 to 3 mm, and the diameter (distance indicated by D in FIG. 3) is 0.02 to 0.1 mm. Preferably there is. When the length of the hair body 12 is less than 0.2 mm, it is not preferable because the deformability of the hair body becomes small. When the length of the hair body 12 exceeds 3 mm, the heat transfer distance becomes long, This is not preferable because the thermal resistance becomes relatively large. In addition, when the diameter of the hair 12 exceeds 0.1 mm, the deformability is small, which is not preferable. When the diameter is less than 0.02 mm, the contact area per hair 12 is relatively small. This is not preferable because the amount of heat transfer is reduced and efficient cooling cannot be performed.

  Further, each hairy body 12 preferably has an L / D value of 10 to 150. If the value of L / D is less than 10, the rigidity becomes so high that only a small number of hairs 12 can contact the heat generating part 1 and the heat radiating part 2 and a sufficient heat transport capability is not exhibited. On the other hand, if the value of L / D exceeds 150, it becomes difficult to bring the hair 12 into contact with the contact surfaces of the heat generating portion 1 and the heat radiating portion 2 substantially perpendicularly, so that heat transport cannot be sufficiently performed. This is not preferable because the heat transport capability is insufficient.

Furthermore, it is preferable that the hairs 12 satisfying the above-mentioned shape exist at a density of 10 to 1000 / mm ² per unit area on the base 11. When the existence density is less than 10 / mm ² , the heat transfer amount is relatively lowered, which is not preferable. Moreover, when it exceeds 1000 / mm < ² >, it will be in an overcrowded state and it will become difficult to ensure the space for the hair body 12 to deform | transform (bend), and as a result, the deformation | transformation (bend) amount of the hair body 12 will become small. Therefore, it is not preferable because the number of contacts of the hair-like body 12 with respect to the heat generating portion 1 is reduced.

  In this way, the plurality of hairs 12 can be in contact with the heat generating part 1 or the heat radiating part 2, and since the hairs 12 have appropriate flexibility, for example, the heat generating part 1 or the heat radiating part 2. Even if there is a warp or a flaw in the contact portion with the ciliary body 12, the ciliary body 12 can be deformed to follow the warp or the flaw, so that stable heat transfer can be realized. .

  Next, the manufacturing method of the heat transporter 10 in the present invention will be described. First, a fiber on which raising or flocking is uniformly applied is prepared. As a method for producing a fiber with brushed fibers, for example, a pile is woven using a part of a warp yarn between two woven fabrics such as a knitted fabric and a woven fabric, and this is divided into two pieces to achieve high density and uprightness. It is possible to produce a fiber that is excellent in raising. FIG. 4 schematically shows the fabric on one side after the two fabrics are cut. As shown in FIG. 4, since one yarn is composed of stranded wires formed by a plurality of filaments F, the fiber density (1 / P × 1 / P is maintained with the same raised pitch P by increasing the number N of filaments. × N) can be easily increased.

  On the other hand, the fiber to which flocking has been applied can be produced by an electrostatic flocking method. In this method, the fiber to be planted is cut to a desired length, passed through a sieve, and then dispersed in the space between the base fiber and the electrode plate, and between the base fiber and the electrode plate. The hair is planted by applying a voltage of tens of thousands of volts.

  Cu thus obtained is plated on the fibers that have been subjected to raising or flocking, and then the plated fibers are heat-treated to remove or carbonize the fibers. Thereby, the base | substrate part 11 and the hair-like body 12 standing by this can be formed with the material which has Cu as a main component. Thus, the heat transporter 10 can be manufactured at a lower cost than in the prior art by plating Cu on the fibers that have undergone raising or flocking. In addition, it is very difficult to form the heat transport body 10 similar to the present invention by the conventional pressing method.

  The raised or flocked fibers that are preferably used for the above-described fibers to be plated are preferably such that the heights of the tips are as uniform as possible. By aligning the height of raising and the length of flocking, the obtained plurality of hairs 12 can be brought into uniform contact with the heat generating portion 1 and the heat radiating portion 2. Needless to say, the length (height) of raised or flocked hair and the density existing on the base fiber are the same as the above-described density and length of the hairy body 12. .

  When the density of raised or flocked fibers that become the protruding portion of the fiber is high or the height is too high, the plating solution does not sufficiently penetrate to the lower portion of the protruding portion, and the lower portion of the resulting hairy body 12 is sufficient. An undesirable Cu film is not formed or the film thickness is reduced, which reduces the amount of heat transfer, which is not preferable. The protruding portion of the fiber is removed by heat treatment after plating. Thereby, the hollow part H of the hair-like body 12 is formed in the part corresponding to the protrusion part. In order to produce the hair 12 having a predetermined shape, it is necessary to produce the hair 12 while controlling the diameter of the protruding portion of the fiber and the plating thickness.

  The material of the fiber used for producing the heat transporter 10 of the present invention is not particularly limited as long as it can be removed by heat treatment. For example, acrylic, cellulose-based rayon, polyamide-based fibers such as nylon, chemical fibers such as polyester, natural fibers such as cotton, silk, and hemp can be used. However, from the viewpoint of controlling the diameter of the protruding portion as described above, a chemical fiber that can relatively easily control the fiber diameter is more preferable.

  In particular, it is preferable to use rayon as the material of the protruding portion of the fiber that will form the hollow portion H after the heat treatment. This is because rayon is relatively soft among chemical fibers, and is particularly easy to process when cutting and aligning to a desired length.

When Cu plating is performed on these fibers, since most of these fibers are not conductive, a relatively thin film is first formed on the fibers by electroless plating, and then the base 11 and It is preferable to form the hairy body 12. In electroplating, the amount of Cu deposited on the fiber can be controlled in accordance with the amount of current to flow, so that the diameter of the hair 12 can be set to a desired size. Moreover, regarding the adhesion amount of Cu in electroless plating and electroplating, 500-2000 g / m < ² > is preferable. If the adhesion amount of Cu is less than 500 g / m ² , the fiber cannot be completely covered. On the other hand, when it is more than 2000 g / m ² , the protruding portions of adjacent fibers are connected to each other, and the hairy body 12 cannot be formed.

  After applying Cu plating to the fiber, the fiber is removed. There is a method for removing fibers by heat treatment. For example, heat treatment is performed at a temperature at which the fiber starts to decompose, for example, at a temperature of 300 ° C. or higher in an inert gas atmosphere such as nitrogen or vacuum. Thereafter, for example, the residue can be burned in the atmosphere, and the oxide film formed on the surface of Cu can be heat-treated in a reducing atmosphere such as hydrogen to reduce the surface copper oxide.

  Further, the temperature for heat treatment in an inert gas atmosphere is preferably 300 ° C. or higher, and needs to be 1085 ° C. or lower, which is the melting point of Cu. In particular, 500-950 degreeC is preferable and about 700-900 degreeC is more preferable. Heat treatment within this temperature range is preferable because when the fibers are decomposed, the decomposition products are easily removed by a combustion process in the atmosphere. In particular, if the temperature is 500 ° C. or higher, the thermal decomposition of the fiber itself proceeds, so that it is difficult for residues to remain in the ciliary body when heat-treated in the atmosphere. Furthermore, if it is 700 degreeC or more, a residue will hardly remain.

  It is also possible to burn in the atmosphere without performing heat treatment in an inert gas atmosphere or vacuum. However, in this case, the fiber itself burns and the temperature of the Cu film also rises. As a result, the oxide film on the surface of the Cu film may become thick, which is not preferable. In other words, if the oxide film on the surface of the Cu film becomes too thick, it can be reduced on the surface even if it is reduced in hydrogen, but the oxide film tends to remain inside the hollow part, and the thermal conductivity of the entire hair is reduced. Since it falls, it is not preferable.

  The temperature for reduction with hydrogen is preferably 300 ° C. or higher. At temperatures lower than this, the rate of the Cu reduction reaction is slow and is not very effective. Considering the efficiency, about 500 to 800 ° C. is preferable. Moreover, if it reduces at the temperature over 1000 degreeC, Cu will lose elasticity, and will be in the annealed state. For this reason, even if the tip of the hair 12 contacts the heat generating part 1 or the heat radiating part 2 at the contact part between the hair 12 and the heat generating part 1 or the heat radiating part 2, only the deformation of the hair 12 becomes large. As a result, the contact area between the hair 12 and the heat generating part 1 or the heat radiating part 2 becomes small, which is not preferable.

  As mentioned above, although the heat transport body of this invention was demonstrated based on the specific example, this invention is not limited to the specific example which concerns, It can implement in the various aspect of the range which does not deviate from the main point of this invention. That is, the technical scope of the present invention extends to the claims and their equivalents.

[Example 1]
A ceramic heater having a size of 32 mm square and a thickness of 2 mm was prepared as the heat generating unit 1 as if it were a CPU of a personal computer. A lead wire was attached to this so that heat could be generated by passing an electric current. Next, as the heat radiating part 2, a heat sink provided with aluminum radiating fins of 60 mm square × height 30 mm was prepared.

In order to produce the heat transport body 10 interposed between the heat generating portion 1 and the heat radiating portion 2, a pile is woven using a part of the warp yarn between two woven fabrics, and this is cut into two pieces to obtain a thickness. Brushing was performed on one side of a 0.5 mm base part, and four types of polyester fibers having different brushing lengths as shown in Table 1 below were prepared. These four types of fibers were each subjected to electroless Cu plating, and electrolytic Cu plating was performed at a basis weight of 1500 g / m ² . The fiber was subjected to Cu plating and then fired at 800 ° C. for 1 hour in an N ₂ atmosphere. Thereafter, further baked at 800 ° C. in _{N 2} atmosphere of _{H 2} were mixed 15 mol%, to obtain a heat transport of Samples 1-4.

  The heat transport bodies of Samples 1 to 4 obtained in this way were set so that the hair 12 is in contact with the heat generating part 1 and the base part 11 is in contact with the heat radiating part 2, and the base part 11 is used as the filler 13. Ag grease was injected. A power of 60 W was supplied to the ceramic heater of the heat generating part 1, and the temperature difference ΔT between the heat generating part 1 and the heat radiating part 2 was measured. The measurement results are shown in Table 1 below.

[Example 2]
Heat transporters of Samples 5 to 7 as shown in Table 2 below were prepared in the same manner as in Example 1 except that raised fibers were used on both sides of the base part. This was set between the heat generating part 1 and the heat radiating part 2, and thereafter, the filler 13 was injected in the same manner as in Example 1 and ΔT was measured. The measurement results are shown in Table 2 below. Samples 6 and 7 used heat sinks having a large warpage as compared with Example 1.

[Example 3]
In the same manner as in Example 1, heat transporters of Samples 8 to 12 as shown in Table 3 below were prepared. ΔT was measured in the same manner as in Example 1 except that a filler 13 made of Pb-free solder or an Ag brazing material was used for Samples 8 to 12 and the operating temperature was 200 ° C. A heat-resistant member was used as a covering material for the power supply cable to the heater. The measurement results are shown in Table 3 below.

[Comparative Example 1]
As a heat transport body of the sample 13 interposed between the heat generating portion 1 and the heat radiating portion 2, a convex structure portion 3 in which a large number of Cu columnar bodies 3b are gathered on one side of a Cu base portion 3a as shown in FIG. Was formed by wire electric discharge machining. The convex structure 3 has a plurality of columnar bodies 3b each having a height of 0.5 mm and a cross-section of 0.1 × 0.1 mm on a Cu base portion 3a having a thickness of 1 mm with a spacing of 0.4 mm. It has a regularly arranged structure. At this time, the existence density of many columnar bodies 3b was 6.25 pieces / mm ² . The columnar body 3b and the base portion 3a of the convex structure portion 3 are set so as to contact the heat generating portion 1 and the heat radiating portion 2, respectively, and the temperature difference ΔT between the heat generating portion 1 and the heat radiating portion 2 in the same manner as in the first embodiment. Was measured.

[Comparative Example 2]
A Cu metal porous body 4 (Celmet, PPI = 50) having a thickness of 1.5 mm as shown in FIG. 8 was prepared as a heat transport body of the sample 14 interposed between the heat generating portion 1 and the heat radiating portion 2. . The Cu metal porous body 4 was set so as to contact the heat generating portion 1 and the heat radiating portion 2, and the temperature difference ΔT between the heat generating portion 1 and the heat radiating portion 2 was measured by the same method as in Example 1.

[Comparative Example 3]
The base part 11 of the heat transport body 10 similar to that of Example 1 was connected to the heat dissipation part 2 through the silicone adhesive 5 as shown in FIG. The temperature difference ΔT between the heat generating part and the heat radiating part was measured by the same method as in Example 1 using the transporter. The results of Comparative Examples 1 to 3 are summarized in Table 4 below.

  From the results of Tables 1 to 4, it was found that Example 1 can efficiently transport heat compared to Comparative Examples 1 to 3. Moreover, when raising both surfaces of Example 2, it turned out that the performance more than equivalent to Example 1 is obtained. In particular, in the case of a heat sink with a large warp, double-sided raising efficiently transported heat compared to single-sided raising. This indicates that the hair is more efficiently transferred to the heat sink with a large warp than the base. Since the rigidity of the columnar body is high in the heat transport body of Comparative Example 1, the tip of the columnar body cannot be satisfactorily brought into contact with the recess of the heat generating portion 1 as shown in FIG. I think that the.

  It can also be seen that by using the filler 13 as a solder or an Ag brazing material, it can be used satisfactorily even in a high temperature atmosphere of 200 ° C. that cannot be used in a resin system such as Ag grease. Furthermore, it can be seen that solder and Ag brazing material as filler 13 have higher thermal conductivity and heat transport efficiently than Ag grease.

DESCRIPTION OF SYMBOLS 1 Heat generating part 2 Heat radiating part 10 Heat transporter 11 Base part 12 Hairy body 13 Filler

Claims (4)

A heat transport body interposed between a heat generating portion and a heat radiating portion that radiates heat generated in the heat generating portion, and is substantially on a surface of the base portion and the surface of the base portion facing the heat generating body and / or the heat radiating portion. A plurality of hair bodies having a hollow portion provided vertically, the base portion and the plurality of hair bodies are mainly composed of Cu and formed by plating,
Either the base portion or the tips of the plurality of hairs are in direct contact with the heat generating body and the heat radiating portion, and the base portion or the plurality of hairs are in contact with at least one of the heat generating body and the heat radiating portion. The heat transporter is characterized in that the filler is filled in a void portion of the base portion or a void portion between the plurality of hair bodies.   The heat transporter according to claim 1, wherein the plurality of hairs are provided on both surfaces of the base portion.   The heat transporter according to claim 1 or 2, wherein the filler is a resin containing at least one selected from the group consisting of metal, ceramic, and carbon as a high thermal conductive filler. .   The heat transporter according to claim 1, wherein the filler is solder or brazing material.

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