JP4543864B2 - Heat dissipation component and manufacturing method thereof - Google Patents

Description

  The present invention relates to a heat radiating component suitable for application to metal parts such as heat sinks for various transistors, heat pipes, heat sinks for CPUs, and the like, and a method for manufacturing the same. Specifically, the heat-dissipating part is provided with a magnetic body provided so as to surround the entire surface of the heat-dissipating member constituting the heat-dissipating component or a part of the outer periphery thereof, and the heat-generating object is not deteriorated in heat conductivity from the heat-generating object to the heat dissipating body. It is possible to prevent leakage of electromagnetic waves from the heat sink to the heat dissipating body, to suppress generation of unnecessary electromagnetic radiation, and to provide a highly reliable metallic heat dissipating component with good thermal conductivity.

  In recent years, electronic devices have been trending toward miniaturization, but the amount of electric power (heat generation amount) cannot be reduced so much due to the variety of applications and high-speed data processing. Therefore, heat radiation countermeasures in electronic devices are more important. As heat dissipation measures (heat measures) in electronic devices, heat sinks, heat pipes, heat sinks and the like made of metal materials having high thermal conductivity such as copper and aluminum are often widely used.

  These heat radiating components excellent in thermal conductivity are arranged in a heat generating part (high temperature place) in the electronic device or arranged from the heat generating part to the heat radiating part (low temperature place). The heat dissipating component is used to achieve a heat dissipating effect or temperature relaxation in the device.

  FIG. 13 is a conceptual diagram illustrating a configuration example and a function example of the heat dissipation component 500 according to the first conventional example. A heat dissipating component 500 shown in FIG. 13 includes a heat dissipating plate 1 and a heat dissipating filler sheet (space filler) 2. An LSI device (semiconductor integrated circuit device) 3 serving as a heat generation source is mounted on a printed circuit board 5. A heat radiating plate 1 having a predetermined size is joined on the LSI device 3 with a heat radiating filler sheet 2 interposed therebetween. The reason why the heat dissipating filler sheet 2 is sandwiched between the LSI device 3 and the heat dissipating body 1 is to eliminate the space at the joint and improve the thermal conductivity.

  In FIG. 13, the magnetic field distribution II shown by the dotted line is due to the high frequency magnetic field generated from the LSI device 3 that operates at a high frequency in units of several hundred MHz. In the figure, a waveform arrow indicates propagation (direction) of an electromagnetic wave signal having a frequency component. The electromagnetic wave signal is generated when the high frequency magnetic field is linked to the heat sink 1. The electromagnetic wave signal is radiated to the periphery of the LSI device 3 as electromagnetic wave unnecessary radiation noise IV. In the figure, thick arrows indicate heat propagation (direction). In this example, the heat propagated from the LSI device 3 through the heat dissipating filler sheet 2 is dissipated in a direction away from the LSI device 3.

  FIG. 14 is a conceptual diagram illustrating a configuration example and a function example of a heat dissipation component 600 according to the second conventional example. According to the second conventional example, a heat radiation & magnetic filler sheet (space filler) 4 is provided in place of the heat radiation filler sheet 2.

  A heat dissipating component 600 shown in FIG. 14 includes a heat dissipating plate 1 and a heat dissipating & magnetic filler sheet 4. On the LSI device 3 mounted on the printed circuit board 5, a heat sink 1 having a predetermined size is joined via a heat dissipation & magnetic filler sheet 4. The reason why the heat radiation & magnetic filler sheet 4 is sandwiched between the LSI device 3 and the heat radiating body 1 is to reduce the electromagnetic radiation unnecessary radiation noise IV at the expense of a little thermal conductivity at the joint.

  In FIG. 14, the magnetic field distribution II indicated by the dotted line is due to the high-frequency magnetic field generated from the LSI device 3 that operates at a high frequency in units of several hundred MHz. In the figure, the electromagnetic wave signal indicated by the waveform arrow reduces the electromagnetic wave unnecessary radiation noise IV compared to the first conventional example, but in proportion to this, the amount of heat propagation indicated by the thick arrow in the figure is also the first. Compared to conventional examples. This is because a magnetic material is mixed in the heat dissipation sheet.

  In relation to this type of electromagnetic wave absorption technology, Patent Document 1 discloses a radio wave absorbing heat conducting sheet. According to the radio wave absorption heat conduction sheet, a soft sheet having a heat-resistant temperature of 150 ° C. or more and a rubber hardness of 50 or less, 100 parts by weight of liquid silicon resin, 300 parts by weight of soft magnetic powder, and non-magnetic inorganic powder It is composed of a ratio of 100 parts by weight of the body. When the radio wave absorption heat conductive sheet having such a configuration is provided between the heat sink and the CPU, the effects of both the noise radio wave absorption and the high heat conductivity that absorbs the heat generated by the CPU and leads to the outside can be obtained. That's it.

  Patent Document 2 discloses an electromagnetic wave suppression sheet and an electromagnetic wave suppression heat conduction sheet. According to this electromagnetic wave suppression heat conductive sheet, it has an electromagnetic wave suppression sheet and a soft heat dissipation sheet. The electromagnetic wave suppression sheet is formed by mixing a soft magnetic powder and a heat conductive filler in a silicon-based resin. The soft heat dissipation sheet is formed by mixing a heat conductive filler in a silicon-based resin. The electromagnetic wave suppression sheet is provided with an opening having a size that can be covered with a heat dissipation sheet. This opening is aligned with the heat generation part of the CPU. Between the heat radiating plate and the CPU, an electromagnetic wave suppression sheet having an opening and a heat radiating sheet connected to a heat pipe are stacked so as to close the opening.

  If the electromagnetic wave suppression heat conductive sheet having such a configuration is provided between the heat sink and the CPU, the effects of both noise countermeasures and heat countermeasures in an electronic device that generates high heat and high frequency noise can be obtained.

  Furthermore, Patent Document 3 discloses a method for manufacturing a printed board cooling apparatus. According to the method for manufacturing a printed board cooling apparatus, first, an insulating layer is formed on the entire surface of the electronic component mounted on the printed board. Thereafter, a permanent magnet is disposed in a region surrounding the series of electronic components. Thereafter, a magnetic cooling medium is injected between the insulated electronic components. Further, a heat radiating plate is formed on the printed circuit board including electronic components and permanent magnets. Thereafter, the permanent magnet is cured while preventing the magnetic cooling medium from flowing out. By manufacturing a printed board cooling device in this way, the heat generated from the electronic components can be quickly dissipated to the outside, and the device can be provided at low cost without the need for troublesome sealing work. is there.

Japanese Patent Laying-Open No. 2001-066831 (page 3 in FIG. 3) Japanese Patent Laying-Open No. 2002-185183 (FIG. 2 on page 3) JP 58-014592 A (2nd page, Fig. 1)

  By the way, according to the heat radiating component and its manufacturing method according to the conventional example, there are the following problems.

  i. The heat-dissipating parts having excellent thermal conductivity as seen in Patent Documents 1 to 3 pick up harmonic components of electric signals as a side effect because they are metal, and as a result, cause of unnecessary electromagnetic radiation. It often becomes. Incidentally, an IC chip (semiconductor package) having a high current density is mainly used as a heat generating part (high temperature place) in an electronic device.

  ii. In addition, a high current density means that the electric field or magnetic field intensity that can be a component of electromagnetic wave unnecessary radiation is also large. For this reason, when the heat dissipating component is disposed in a place such as a semiconductor package, the harmonic component of the electric signal is often picked up together with the heat. Since the heat dissipating part is made of a metal material, the heat dissipating part itself often functions as an antenna of harmonic components.

  iii. Under these circumstances, it is best to fill the bonding space between the semiconductor package (hereinafter also referred to as a heat generating object) and the heat dissipation component with a high thermal conductive filler, whereas as shown in FIG. In order to cut off the coupling, a space filler (heat dissipation & magnetic filler sheet 4 etc.) combined with a magnetic material may be used. Of course, by combining a magnetic material with a heat-dissipating sheet (hereinafter also referred to as a heat-dissipating body), the thermal conductivity of the space filler is reduced, so the heat-dissipating efficiency is also reduced.

  iv. In order to avoid coupling of harmonic components, a method of arranging a heat dissipating component by providing a certain distance from a place where the electric field or magnetic field strength is large is also conceivable. This method hinders the demand for downsizing of electronic devices.

  Therefore, the present invention solves such a conventional problem, and makes it possible to prevent leakage of electromagnetic waves from the heat generating object to the heat radiating body without reducing the thermal conductivity from the heat generating object to the heat radiating body. Another object of the present invention is to provide a heat dissipating component capable of suppressing generation of electromagnetic radiation and providing a highly reliable metal heat dissipating component having good thermal conductivity and a manufacturing method thereof.

The above-described problem is that a heat sink that is a semiconductor integrated circuit device has a portion for attaching heat to radiate heat or conduct heat and surround the surface of the heat sink and the electric current flowing through the heat sink And a magnetic body that attenuates the signal component, and soft magnetic particles are dispersed in an organic medium.

According to the heat dissipating component according to the present invention, a CPU such as an electronic device that handles an ultra-high frequency signal in GHz is attached to a portion where the heat generating object is attached. Heat generated by the high-speed operation of the CPU is radiated or conducted by a metallic heat radiator. A magnetic body is provided in an annular shape on the outer peripheral portion of the heat dissipating member so as to close the magnetic path so as to surround the surface of the heat dissipating member at a position close to the CPU mounting portion.

Therefore, it is possible to prevent leakage of electromagnetic waves from the heat generating object to the heat dissipating member by the magnetic material without reducing the thermal conductivity from the heat generating object to the heat dissipating member. Thereby, it is possible to provide a highly reliable metallic heat dissipation component that suppresses the generation of electromagnetic radiation unnecessary radiation.

A method of manufacturing a heat radiating component according to the present invention includes a step of forming a heat radiating body having a portion to which a heat generating object as a semiconductor integrated circuit device is attached and radiating heat, and surrounds the surface of the heat radiating body and closes a magnetic path. And a step of attenuating an electrical signal component flowing in the heat sink and forming a magnetic body in which soft magnetic particles are dispersed in an organic medium. It is.

  According to the method for manufacturing a heat radiating component according to the present invention, it is possible to manufacture a highly reliable metal heat radiating component that suppresses the generation of electromagnetic radiation and has good thermal conductivity.

  The heat dissipating component according to the present invention includes a magnetic body provided so as to surround the entire surface of the heat dissipating body or a part of its outer periphery.

  With this configuration, it is possible to prevent leakage of electromagnetic waves from the heat generating object to the heat dissipating member by the magnetic material without reducing the thermal conductivity from the heat generating object to the heat dissipating member. Therefore, it is possible to provide a highly reliable metallic heat dissipation component that suppresses the generation of electromagnetic radiation.

  According to the method for manufacturing a heat radiating component according to the present invention, the method includes the step of forming a magnetic body so as to surround the entire surface of the heat radiating body or a part of the outer periphery thereof.

  With this configuration, it is possible to manufacture a highly reliable metallic heat-radiating component that suppresses the generation of electromagnetic radiation and has good thermal conductivity.

Subsequently, an embodiment of a heat dissipation component and a manufacturing method thereof according to the present invention will be described with reference to the drawings.
In each example, focusing on the high frequency signal conduction characteristics and heat conduction characteristics in the heat dissipation component, the electrical signal component flowing in the heat dissipation component is attenuated without reducing the heat conduction from the heat generating object to the heat dissipation body, and heat dissipation. Unnecessary radiation from the parts can be reduced, and both the thermal problem and the EMC problem can be solved.
[Example 1]

FIG. 1 is a diagram showing a configuration example of a heat dissipation component 100 as a first embodiment according to the present invention.
In this embodiment, the magnetic material is arranged in the electric signal path of the heat radiating component 100, that is, the magnetic material is arranged annularly on a part of the surface, so that the electric signal component flowing through the heat radiating component 100 can be attenuated. .

  A heat radiating component 100 shown in FIG. 1 has a heat radiating plate 10 as an example of a metallic heat radiating body, and radiates heat. The heat radiating plate 10 is provided with a portion for attaching a heat generating object. This portion is an intrusion place I of an electrical signal (hereinafter referred to as an electromagnetic wave signal) of a heat generating object such as a CPU (Central Processing Unit) or a high frequency transistor having a frequency.

  In this example, a magnetic body (magnetic material) 11 is provided on a part of the surface of the heat radiating plate 10 so as to surround the outer periphery thereof. The magnetic body 11 is provided in an annular shape on the outer peripheral portion of the heat sink 10 so that the magnetic path is closed, for example. Moreover, the magnetic body 11 is provided at a position close to a portion to which the heat generating object is attached (hereinafter referred to as a heat generating member attaching portion). This is because the closer to the heating element mounting portion, the higher the attenuation effect of the electric signal component that tends to flow into the heat radiating plate 10.

  The magnetic body 11 has a sheet shape having a structure in which soft magnetic particles are dispersed in an organic medium. As the soft magnetic particles, Fe, Co, Ni, FeNi, FeCo, FeAl, FeSi, FeSiAl, FeSiB, CoSiB, or ferrite are used. The magnetic body 11 is not limited to this, and the magnetic body 11 may have a structure in which a liquid material having a structure in which a soft magnetic film is dispersed in an organic medium is formed by a coating process. The magnetic body 11 may have a structure in which soft magnetic particles are formed by sputtering, vapor deposition, or plating and integrated with the heat sink 10.

  FIG. 2 is a side view showing an example of attachment of the heat dissipation component 100 ′ to the LSI device 13. A heat radiating component 100 ′ shown in FIG. 2 includes a heat radiating plate 10 and a magnetic body 11. The LSI device (semiconductor integrated circuit device) 13 is obtained by integrating a CPU, a memory, and the like, and is mounted on the printed circuit board 15, for example. The LSI device 13 has a plurality of lead pins 14 and is soldered to the printed circuit board 15 via the lead pins 14.

  A heat radiating plate 10 having a predetermined size is joined to the LSI device 13 with a heat radiating filler sheet (space filler) 12 interposed therebetween. The reason for sandwiching the heat dissipating filler sheet 12 is to eliminate the space at the joint and improve the thermal conductivity. A magnetic body 11 is provided on a part of the surface of the heat radiating plate 10 so as to surround the outer periphery thereof. The magnetic body 11 is provided in an annular shape on the outer periphery of the heat sink 10 so that the magnetic path is closed.

  FIG. 3 is a side view showing a functional example of the heat dissipation component 100 ′ attached to the LSI device 13. In FIG. 3, the magnetic field distribution II indicated by the dotted line is generated by the high frequency magnetic field when the LSI device 13 operates at a high frequency in units of several hundred MHz, for example. In the figure, a waveform arrow indicates propagation (direction) of an electromagnetic wave signal having a frequency component. The electromagnetic wave signal is generated when the high frequency magnetic field is linked to the heat sink 10. The amplitude of the electromagnetic wave signal after passing through the magnetic body 11 is smaller than the amplitude before passing through the magnetic body 11. By passing through the inside of the magnetic body 11, the amount of electromagnetic wave signal (noise signal) is drastically reduced. This is because the magnetic body 11 exhibits a noise suppressing effect.

  In the figure, thick arrows indicate heat propagation (direction). In this example, the heat propagated from the LSI device 13 through the heat dissipating filler sheet 12 propagates through the magnetic body 11 without the heat trapping inside the magnetic body 11. The heat is dissipated in a direction away from the LSI device 13 without changing its transmission amount.

  FIG. 4 is a cross-sectional view illustrating a schematic example of a conductive path and a heat conductive path of an electromagnetic wave signal in a metal plate such as a heat radiating plate. FIG. 5 is a table showing an example of the relationship between the frequency f (GHz) related to the skin effect and the skin depth δ (μm) of various metals.

  In FIG. 4, point P is a power supply point for a signal having a frequency component (such as an electromagnetic wave signal) and is a heat supply point. The electromagnetic wave signal having frequency characteristics from the supply point P shown in FIG. 4 is conducted only on the surface of the metal plate due to the skin effect. On the other hand, heat from the supply point P is also conducted inside the metal plate. Here, when the angular velocity of the electromagnetic wave signal is ω, the magnetic permeability of the magnetic body 11 is μ, the electrical conductivity of the metal plate is σ, and the skin depth at which the electromagnetic wave signal having frequency characteristics can be conducted is δ, The skin depth δ is expressed by equation (1), that is,

  It is calculated by. The table shown in FIG. 5 shows the skin depth δ for each frequency of copper, aluminum, and iron, which are typical metal plates calculated in this way. According to this table, the frequency f of the electromagnetic wave signal is 0.1, 0.3, 0.5, and 1.0 (GHz), and in the case of copper, the skin depth δ is 6.61, 3.82, 2.96 and 2.09 (μm). In the case of aluminum, the skin depth δ is 7.96, 4.59, 3.56, and 2.52 (μm). In the case of iron, the skin depth δ is 15.92, 9.19, 7.12, and 5.03 (μm). It can be seen that the skin depth δ becomes shallower as the frequency f increases.

  It can be seen that the electromagnetic wave signal having frequency characteristics shown in FIG. 5 is conducted through a metal plate such as the heat radiating plate 10 at a surface depth δ of several μm to several tens of μm. Considering such a skin effect, the electromagnetic wave unnecessary radiation can be reduced by attenuating the electromagnetic wave signal on the surface of the heat radiating (metal) component.

  In order to reduce the electromagnetic wave signal having frequency characteristics, it is desirable to dispose a material having loss characteristics, for example, a magnetic material in the signal path. A material having a magnetic loss is particularly used as a material for reducing the electromagnetic wave signal. The suppression effect of the electromagnetic wave signal is larger as the material having a larger magnetic loss, and generally high permeability magnetic metal powder such as Fe, Co, Ni, FeNi, FeCo, FeAl, FeSi, FeSiAl, FeSiB, CoSiB, etc., or spinel ferrite It is preferable to disperse a high permeability magnetic oxide powder such as in a resin binder.

Here, a mechanism for converting an electromagnetic wave signal into heat energy will be described. The electrothermal conversion mechanism is mainly classified into three types: “conductive loss”, “dielectric loss”, and “magnetic loss”. In addition, when the electric field by the electromagnetic wave signal is E, the magnetic field is H, the frequency is f, and the electromagnetic wave absorption energy per unit volume is P [W / m ³ ], P is an expression (2), that is, ,

However, conductivity: σ
Complex dielectric constant: ε = ε'-jε "
Complex permeability: μ = μ′−jμ ”
It is calculated by.

  In the above equation (2), the first term represents the conduction loss, the second term represents the dielectric loss, and the third term represents the magnetic loss. In particular, as a material for reducing an electromagnetic wave signal, a magnetic material that is a material having loss characteristics in the high frequency band as described above is used. In addition, it is considered that eddy current loss caused by using metal magnetic powder can also be used for energy absorption.

  Then, the manufacturing method of the thermal radiation component which concerns on this invention is demonstrated. In this embodiment, a step of forming a heat radiating plate 10 that has a portion for attaching a heat generating object and radiates heat, and a magnetic body 11 is formed so as to surround the entire surface of the heat radiating plate 10 or a part of its outer periphery. And a step of attaching the heat radiating plate 10 on which the magnetic body 11 is formed to the heat generating object.

Of commercially available generally as electromagnetic wave absorbing coating material, and that its use paint on the substrate, in order in which paint around the chip (semiconductor package), concerned about the short wave signals, magnetic metal Instead of using powder as it is, it is used by coating with an insulator such as oxide. Therefore, an increase in cost cannot be avoided.

  On the other hand, in the present invention, since the heat dissipator is provided in an annular shape, there is no need to worry about short-circuiting of the electromagnetic wave signal, so that the metal magnetic powder can be used as it is. In addition, it is considered difficult to manufacture the high permeability granular film at the printed circuit board 15 or the case level because heat treatment is required. However, since the heat sink 10 is made of metal, heat treatment is also possible. It is possible to apply a granular film. Furthermore, since a large characteristic change with respect to impurities is not observed, a high permeability ferrite film can be applied.

[Create heat sink]
First, a heat radiating plate 10 having a portion to which an LSI device 13 as an example of a heat generating object is attached is formed. For the heat sink 10, for example, aluminum having a predetermined size and thickness is used. Of course, the present invention is not limited to this, and a copper or iron plate having a predetermined size and thickness may be used. A portion to which the LSI device 13 is attached (a heat generating portion mounting portion) may be adjusted to a size facing the joint portion of the LSI device 13. For example, it may be cut out from one aluminum plate and processed, and then an LSI mounting portion may be provided at one end portion of the heat radiating plate 10, or a part thereof may be bent to provide a chip mounting allowance.

  When a screw hole or the like is required for the LSI mounting portion, an opening process is performed. If female threading is necessary, female threading work is also performed. For example, when the frequency f of the electromagnetic wave signal is 1.0 (GHz), the skin depth δ of aluminum is 2.52 (μm). The thickness of aluminum is thick when heat conductivity is improved or when threading is necessary.

[Formation of magnetic material on heat sink]
Next, the magnetic body 11 is formed so as to surround the entire surface of the heat radiating plate 10 or a part of the outer periphery thereof. In this example, the magnetic body 11 is formed in an annular shape so that the magnetic path is closed with respect to the entire surface of the heat radiating plate 10 or a part of the outer periphery thereof. For example, regarding the method of arranging the magnetic material, a sheet-shaped magnetic body 11 having a structure in which soft magnetic particles are dispersed in an organic medium is attached to the entire surface of the heat radiating plate 10 or a part of the outer periphery thereof. Alternatively, a liquid magnetic material 11 having a structure in which soft magnetic particles are dispersed in an organic medium is formed by coating. In this example, high magnetic permeability soft magnetic material such as Fe, Co, Ni, FeNi, FeCo, FeAl, FeSi, FeSiAl, FeSiB, CoSiB, or ferrite is used as the soft magnetic particles.

  Regarding the coating treatment at this time, there is a step of applying a liquid material having a structure in which soft magnetic particles are dispersed by adding a particle dispersant such as a surfactant to an organic medium, and then drying the material. desirable. At that time, it is possible to apply a liquid material to an arbitrary portion by masking the screw hole portion of the heat radiating component 100 or a heating portion mounting portion such as an LSI mounting portion in advance. As a coating method at this time, printing, brush coating, spray spraying, or the like is applied. Thereby, the sheet-like magnetic body 11 having a structure in which soft magnetic particles are dispersed in an organic medium can be formed on the entire surface of the heat radiating plate 10 or a part of the outer periphery thereof.

  In this example, for the method of forming the magnetic body 11 on the heat sink 10, in addition to the coating method, a soft magnetic film is formed by plating on the entire surface of the heat sink 10 or a part of its outer periphery. The heat sink 10 and the magnetic body 11 may be integrated. For example, a high permeability granular film or a high permeability ferrite film is formed on the heat sink 10 by plating. According to this plating process, first, a resist is applied in advance to a portion that is not subjected to the plating process, such as a screw hole portion of the heat radiating component 100 or a mounting position on the heat generating portion. Subsequently, after lightly polishing the plated portion, a degreasing process is performed to perform a plating process. Finally, the entire heat sink is cleaned to remove the resist. Thereby, the heat radiating component 100 which integrated the magnetic body 11 and the heat sink 10 can be formed.

  In this example, the method of forming the magnetic body 11 on the heat sink 10 includes sputtering, vapor deposition, and the like on the entire surface of the heat sink 10 or a part of its outer periphery in addition to the coating method and the plating process. Soft magnetic particles may be formed, and the heat radiating plate 10 and the magnetic body 11 may be integrated. For example, a high magnetic permeability granular film or a high magnetic permeability ferrite film is formed on the heat sink 10 by sputtering or vapor deposition. According to the sputtering process, the vapor deposition process, and the like, first, a resist is applied in advance to a portion not to be processed, such as a screw hole portion of the heat dissipation component 100 or a mounting portion to the heat generating portion, in the same manner as the plating process.

Subsequently, sputtering or vapor deposition is performed. As a sputtering or vapor deposition method at this time, a single large plate-like component is collectively processed and then cut (or punched) into a required shape, or a component that has been processed into a required shape in advance is synthesized. A method may be conceived in which a work is carried out in a chamber while feeding a base material, which is attached to a long scroll-shaped base material made of PET (polyethylene terephthalate) which is a kind of resin. It is also possible to perform heat treatment or treatment in a magnetic field at the same time. A substrate such as PET can also be used as an insulating seal as it is. Finally, the entire heat sink is cleaned to remove the resist. Thereby, the heat radiating component 100 which integrated the magnetic body 11 and the heat sink 10 can be formed.
[Mounting to LSI equipment]
Next, the heat sink 10 on which the magnetic body 11 is formed is mounted on the LSI device 13. For example, after mounting the LSI device 13 on the printed circuit board 15, the LSI device 13 and the heat radiating plate 10 on which the magnetic body 11 is formed are connected (joined) with the heat radiating filler sheet 12 interposed therebetween. Thereby, the heat dissipating component 100 'can be attached to the LSI device 13 on the printed circuit board 15 as shown in FIG.

  As described above, according to the heat dissipating component and the manufacturing method thereof as the first embodiment according to the present invention, the LSI device 13 that handles, for example, an ultra-high frequency signal in GHz unit is attached to the LSI attaching portion. Heat generated by the LSI device 13 operating at high speed is radiated by the metallic heat sink 10. A magnetic body 11 is provided in an annular shape on the outer peripheral portion of the heat sink 10 so as to close the magnetic path so as to surround a part of the outer periphery of the surface of the heat sink 10 at a position close to the LSI mounting portion.

  Therefore, leakage of electromagnetic waves from the LSI device 13 to the heat sink 10 can be prevented by the magnetic body 11 without reducing the thermal conductivity from the LSI device 13 to the heat sink 10. Thereby, it is possible to manufacture and provide a highly reliable metallic heat dissipating component 100 that suppresses generation of unnecessary electromagnetic radiation.

Incidentally, in the conventional heat radiating component, the heat radiating filler sheet for filling the space and the magnetic filler sheet for preventing EMC are provided between the heat generating object and the heat radiating plate. However, in the heat radiating component 100 of the present invention, the heat radiating filler is used. Only the sheet 12 may be provided between the LSI device 13 and the heat sink 10. The magnetic filler sheet prevents leakage of electromagnetic waves to the heat radiating plate 10, but has a property of reducing heat dissipation. In the system of the present invention, the thermal conductivity is improved by the amount that the magnetic filler sheet is not interposed. Thus, it can suppress that the metal component itself used as a heat dissipation measure turns into an antenna, and can become a solution of both a thermal problem and an EMC problem.
[ Reference example ]

FIG. 6 is a perspective view illustrating a configuration example of the heat dissipation component 200 as a reference example . The heat radiating component 200 shown in FIG. 6 is configured to attenuate an electromagnetic wave signal component flowing through the heat radiating component by forming (arranging) a magnetic material on the entire surface of the electromagnetic wave signal path of the heat radiating component 200.

  In FIG. 6, the heat dissipation component 200 includes a heat dissipation plate 20, a magnetic body 21, and an LSI attachment portion 22. The heat sink 20 and the LSI mounting portion 22 are made of aluminum. The LSI device 13 and the like are attached to the LSI attachment portion 22. Therefore, the LSI mounting portion 22 becomes an intrusion place I of an electromagnetic wave signal having a frequency. The magnetic body 21 is formed so as to wrap around the entire surface of the heat sink 20 indicated by the wavy line. The magnetic body 21 is formed by coating, plating, sputtering, vapor deposition, or the like. The LSI attachment portion 22 is a portion bent from the heat sink 20 into an L shape. The LSI attachment portion 22 is not subjected to magnetic body formation processing.

According to the heat radiating component 200, the entire surface of the heat radiating plate 20 is wrapped with the magnetic body 21, so that the thermal conductivity from the LSI device 13 to the heat radiating plate 20 is not lowered by the magnetic body 21, as in the first embodiment. Thus, leakage of electromagnetic waves from the LSI device 13 or the like (not shown) to the heat sink 20 can be prevented. Thereby, it is possible to manufacture and provide a highly reliable metallic heat dissipating component 200 in which generation of electromagnetic radiation unnecessary radiation is suppressed.
[ Example 2 ]

FIG. 7 is a perspective view showing a configuration example of a heat sink 300 as the second embodiment. In this embodiment, a magnetic material is disposed in the electromagnetic wave signal path of the heat sink 300 so that the electromagnetic wave signal component flowing in the heat sink 300 is attenuated.

  A heat sink 300 shown in FIG. 7 constitutes a heat dissipation component for the CPU. The heat sink 300 includes a base 30 having a predetermined thickness, a magnetic body 31, and a plurality of cooling fins 32. Fins 32 are arranged in alignment on the base 30. The back surface of the base 30 is an LSI mounting portion (not shown). A CPU is attached to the LSI attachment portion. Therefore, the LSI mounting portion becomes an intrusion place I of an electromagnetic wave signal having a frequency.

  The magnetic body 31 is formed to surround only the side surface of the base 30 in an annular shape. The magnetic body 31 is formed by coating, plating, sputtering, vapor deposition, or the like. By arranging the magnetic body 31 partially in a ring shape on the side surface of the base 30, the electromagnetic wave signal component flowing in the base 30 can be attenuated.

Thus, according to the heat sink 300 according to the second embodiment, the magnetic body 31 is formed so as to surround only the side surface of the base 30 in an annular shape. Therefore, leakage of electromagnetic waves from the CPU to the cooling fins 32 can be prevented by the magnetic body 31 without reducing the thermal conductivity from the CPU to the cooling fins 32. Thereby, the highly reliable heat sink 300 which suppressed generation | occurrence | production of electromagnetic radiation unnecessary radiation can be manufactured and provided.
[ Example 3 ]

FIG. 8 is a perspective view showing a configuration example of a heat pipe 400 as a third embodiment. In this embodiment, a magnetic material is disposed in the electromagnetic wave signal path of the heat radiating tube main body 40 so that the electromagnetic wave signal component flowing through the heat pipe 400 is attenuated.

  A heat pipe 400 shown in FIG. The heat pipe 400 is made of, for example, a copper tube having a predetermined diameter with a flat cross section. A part of the heat pipe 400 is used as an LSI mounting portion or the like. An LSI device or the like is attached to an LSI attachment portion (not shown). Therefore, the LSI mounting portion is a place where an electromagnetic wave signal having a frequency enters.

  The magnetic body 41 is formed to surround only the surface of the heat pipe 400 in an annular shape. The magnetic body 41 is formed by coating, plating, sputtering, vapor deposition, or the like. In the heat pipe 400, the electromagnetic wave signal component flowing through the heat pipe 400 can be attenuated by arranging the magnetic body 41 in a partial annular shape.

Thus, according to the heat pipe 400 according to the third embodiment, the magnetic body 41 is formed so as to surround only the surface of the heat radiating tube main body 40 in an annular shape. Therefore, without lowering the thermal conductivity from the LSI device or the like to the heat pipe body 40, a magnetic material 41, as in the first or second embodiment, leakage of electromagnetic waves from the LSI device to the heat pipe body 40 Can be prevented. Thereby, the highly reliable heat pipe 400 which suppressed generation | occurrence | production of electromagnetic radiation unnecessary radiation can be manufactured and provided.

  Below, the result of having verified the effect of this invention by experiment is demonstrated. FIG. 9 is a schematic diagram showing an experimental example at the time of effect verification according to the present invention.

  According to the experimental example shown in FIG. 9, a copper heat sink 50 having a predetermined shape is used, a signal generator is connected to the power feed point P, and an AC signal having a frequency f is supplied to the power feed point P ′ of the heat sink 50. . The frequency f was varied in the range from 100 MHz to 1 GHz. Then, a receiving antenna 60 is installed at a location about 3 m away from the heat sink 50, and an electromagnetic wave unnecessary radiation amount G is measured by this receiving antenna 60, and an unnecessary radiation amount G depending on the presence or absence of magnetic sheets (magnetic bodies) 51 to 53. The effect of the present invention was verified from the difference.

  The thickness of the heat sink 50 used for this experiment is 0.3 mm. The heat sink 50 has a notch in the xy direction, is bent in a mountain fold in the z direction, and has side lengths a to f. The length of side a is 10 mm. The length of the b side is 10 mm. The length of the c side is 45 mm. The length of the d side is 25 mm. The length of the e side is 20 mm. The length of the f side is 15 mm.

  As the magnetic material, a commercially available sheet (hereinafter referred to as a magnetic sheet) having a thickness of about 0.3 mm to 0.5 mm was cut and prepared in three sizes. Each of the magnetic sheets 51, 52, and 53 has a structure in which soft magnetic particles are dispersed in an organic medium. As the soft magnetic particles, one of high magnetic permeability soft magnetic materials such as Fe, Co, Ni, FeNi, FeCo, FeAl, FeSi, FeSiAl, FeSiB, CoSiB, or ferrite is used.

  In the experiment, when the magnetic sheets 51, 52, and 53 are not attached at all, when the magnetic sheet 51 is attached to the region i, that is, the arrangement area a × b, and the regions i and ii, that is, the arrangement area a. When the magnetic sheets 51 and 52 are pasted on the xb + (cd) × (e + f) region, i to iii regions, that is, the arrangement area a × b + (cd) × (e + f) + d × e region The magnetic sheet 51, 52, 53 was affixed to the electromagnetic wave unnecessary radiation amount G for comparison. The graphs of FIGS. 10 to 12 show examples of measurement results of the electromagnetic wave unnecessary radiation amount G due to the difference in the arrangement area of the magnetic sheets 51, 52 and 53.

  FIG. 10 is a graph showing an example of the result when the magnetic sheet 51 is arranged only in the region i shown in FIG. Similarly, FIG. 11 shows the case where the magnetic sheets 51 and 52 are arranged in the areas i and ii, and FIG. 12 shows the case where the magnetic sheets 51, 52 and 53 are arranged in all the areas i, ii and iii. It is a graph which shows each example of a result.

In each graph, the horizontal axis is the frequency f [Hz]. In the figure, 1E + 08 indicates 1 × 10 ⁸ = 100 [MHz], and 1E + 09 indicates 1 × 10 ⁹ = 1 [GHz]. The vertical axis represents the electromagnetic wave unnecessary radiation amount G [dB]. −1.00E + 01 indicates −1 × 10 ¹ = −10 [dB], and −7.00E + 01 indicates −7 × 10 ¹ = −70 [dB]. In each graph, the solid line indicates the characteristics when the electromagnetic radiation unnecessary radiation amount G is measured as it is without attaching the magnetic sheets 51, 52, 53 to the heat radiating plate 50.

  First, the case where the magnetic sheet 51 is pasted on the region i shown in FIG. 10 is compared with the case where the magnetic sheets 51, 52, 53 are not pasted at all. The arrangement area of the magnetic sheet 51 is a × b (see FIG. 9). A solid line is an electromagnetic wave-free radiation characteristic when the magnetic sheets 51, 52, and 53 are not attached at all. On the other hand, a dotted line is an electromagnetic wave unnecessary radiation characteristic in the state in which the magnetic sheet 51 is installed. The larger the difference between the solid line and the dotted line, the greater the effect of reducing electromagnetic wave unnecessary radiation. According to the electromagnetic wave unnecessary radiation characteristic example shown in FIG. 10, it can be seen that a reduction effect of about several dB clearly appears especially in the frequency band of frequency f = 700 (7E + 08) MHz or more.

  Next, the case where the magnetic sheets 51 and 52 are pasted in the regions i and ii shown in FIG. 11 is compared with the case where the magnetic sheets 51, 52 and 53 are not pasted at all. The arrangement area of the magnetic sheets 51 and 52 is a × b + (cd) × (e + f) (see FIG. 9). A solid line is an electromagnetic wave-free radiation characteristic when the magnetic sheets 51, 52, and 53 are not attached at all. On the other hand, the alternate long and short dash line is an electromagnetic wave unnecessary radiation characteristic in a state where the magnetic sheets 51 and 52 are installed. The larger the difference between the solid line and the alternate long and short dash line, the greater the effect of reducing electromagnetic wave unnecessary radiation. In the electromagnetic wave unnecessary radiation characteristic example shown in FIG. 11, it can be seen that a reduction effect of about several dB clearly appears in the frequency band of frequency f = 700 (7E + 08) MHz or more.

  Furthermore, the case where the magnetic sheets 51, 52, 53 are pasted on all the areas i to iii shown in FIG. 12 and the case where the magnetic sheets 51, 52, 53 are not pasted at all will be compared. The arrangement area of the magnetic sheets 51, 52 and 53 is a × b + (cd) × (e + f) + d × e (see FIG. 9). A solid line is an electromagnetic wave-free radiation characteristic when the magnetic sheets 51, 52, and 53 are not attached at all. On the other hand, a two-dot chain line is an electromagnetic wave unnecessary radiation characteristic in a state where the magnetic sheets 51, 52, and 53 are installed. The larger the difference between the solid line and the two-dot chain line, the greater the effect of reducing electromagnetic wave unnecessary radiation. Also in the electromagnetic wave unnecessary radiation characteristic example shown in FIG. 12, it can be seen that a reduction effect of about several dB appears clearly in the frequency band of frequency f = 700 (7E + 08) MHz or higher.

  Moreover, even if the graph of FIG. 10 and the graph of FIG. 12 are compared, there is no big difference in the effect. Just by arranging the magnetic sheet 51 near the electromagnetic wave signal supply source as in the graph of FIG. It turns out that an effect is acquired. In this experiment, commercially available magnetic sheets 51, 52, and 53 were used, but further improvement in characteristics can be expected by examining the optimum structure and optimum thickness of the heat sink 50.

  Thus, it is possible to manufacture a highly reliable metallic heat dissipation component that solves both the heat problem and the EMC problem. Further, the present invention is not limited to heat radiating components, and can be applied to all metal components used in electronic devices that handle high frequency signals.

  The present invention is extremely suitable when applied to metal heat radiating parts such as heat sinks for various transistors, heat pipes, heat sinks for CPUs, and the like.

It is a figure which shows the structural example of the thermal radiation component 100 as 1st Example which concerns on this invention. It is a side view showing an example of attachment of heat dissipation component 100 'to LSI device 13. 3 is a side view showing an example of functions of a heat dissipation component 100 ′ attached to the LSI device 13. FIG. It is sectional drawing which shows the schematic example of the electroconductive path | route and electromagnetic conduction path | route of an electromagnetic wave signal in metal plates, such as a heat sink. It is a table | surface figure which shows the example of a relationship of the frequency f (GHz) regarding skin effect with skin depth (delta) (micrometer) of various metals. It is a perspective view which shows the structural example of the thermal radiation component 200 as a reference example . It is a perspective view which shows the structural example of the heat sink 300 as a 2nd Example. It is a perspective view which shows the structural example of the heat pipe 400 as a 3rd Example. It is the schematic which shows the experiment example at the time of the effect verification which concerns on this invention. It is a graph which shows the example of a result at the time of arrange | positioning the magnetic sheet 51 only to the area | region of i shown in FIG. It is a graph which shows the example of a result at the time of arrange | positioning the magnetic sheets 51 and 52 to the area | region of i and ii shown in FIG. It is a graph which shows the example of a result at the time of arrange | positioning the magnetic sheets 51, 52, and 53 to all the area | regions of i, ii, and iii shown in FIG. It is a conceptual diagram which shows the structural example of the thermal radiation component 500 which concerns on a 1st prior art example, and its function example. It is a conceptual diagram which shows the structural example of the thermal radiation component 600 which concerns on a 2nd prior art example, and its function example.

DESCRIPTION OF SYMBOLS 10,20 ... Radiator, 11, 21, 31, 41 ... Magnetic body, 12 ... Radiation filler sheet, 30 ... Base, 32 ... Fin for cooling, 50 ... Heat radiation plate, 51-53 ... Magnetic sheet, 100, 100 ', 200 ... Heat radiation component, 300 ... Heat sink (heat radiation component), 400 ... Heat pipe (heat radiation component)

Claims (9)

A metal radiator that radiates heat or conducts heat by having a portion to which a heat generating object that is a semiconductor integrated circuit device is attached;
A magnetic body that surrounds the surface of the radiator and is provided in an annular shape on the outer periphery of the radiator so as to close the magnetic path, and attenuates an electric signal component flowing through the radiator,
The magnetic body is obtained by dispersing soft magnetic particles in an organic medium.   The heat radiating component according to claim 1, wherein the magnetic body is provided at a position close to a portion to which the heat generating object is attached.   The heat dissipation component according to claim 1, wherein the magnetic body has a sheet shape having a structure in which soft magnetic particles are dispersed in the organic medium.   The heat radiating component according to claim 1, wherein the magnetic body has a structure formed by applying a liquid material having a structure in which soft magnetic particles are dispersed in the organic medium.   For the soft magnetic particles, a high magnetic permeability soft magnetic material is used, and the high magnetic permeability soft magnetic material includes Fe, Co, Ni, FeNi, FeCo, FeAl, FeSi, FeSiAl, FeSiB, CoSiB, or ferrite. The heat dissipating component according to claim 1, wherein the heat dissipating component is included. Forming a heat radiating body that radiates heat having a portion to which a heat generating object that is a semiconductor integrated circuit device is attached;
A magnetic material that surrounds the surface of the radiator and is provided in an annular shape on the outer periphery of the radiator so as to close the magnetic path, attenuates an electric signal component flowing through the radiator, and disperses soft magnetic particles in an organic medium. Forming a body, and a method of manufacturing a heat dissipation component.   The sheet-shaped magnetic body having a structure in which soft magnetic particles are dispersed in the organic medium is formed on the entire surface of the surface of the heat radiating body or a part of the outer periphery thereof. Manufacturing method for heat dissipation parts.   7. A liquid magnetic material having a structure in which soft magnetic particles are dispersed in the organic medium is formed by coating on the entire surface of the surface of the radiator or a part of the outer periphery thereof. The manufacturing method of the thermal radiation component as described in 2 ..   The soft magnetic particles are made of a high magnetic permeability soft magnetic material, and the high magnetic permeability soft magnetic material includes Fe, Co, Ni, FeNi, FeCo, FeAl, FeSi, FeSiAl, FeSiB, CoSiB, or ferrite. The method for manufacturing a heat dissipation component according to any one of claims 6 to 8, wherein:

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