JP2009302302A - Heatsink for electronic component and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heatsink for an electronic component, which has a reduced size and a simple structure, and to provide a method of manufacturing the same. <P>SOLUTION: A heatsink 10 for an electronic component includes: a heat-conductive member 12 having a surface which is to be in contact with an electronic component 11; a heat dissipating fin 13 joined to the heat-conductive member 12; and heat-conductive resin members 14 which are integrated with the heat dissipating fin 13 to cover almost the whole of the heat dissipating fin 13 except for the area joined to the heat-conductive member 12, and absorb heat accumulated in the heat-dissipating fin 13 and dissipate the heat into the atmosphere. As the heat-conductive resin members 14 cover almost the whole of the heat dissipating fin 13, the electronic component 11 can be cooled by heat absorption. Cooling effect is enhanced without the need to increase the size of the heat dissipating fin 13, so that the size of the heatsink 10 itself can be reduced. All that is required is to cover the heat dissipating fin 13 with the heat conductive resin members 14, so that the heatsink 10 can have a simple structure. The heatsink 10 using a resin (heat-conductive resin members 14) can be reduced in weight in comparison with a heatsink using a metal. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a heat sink for an electronic component that absorbs and dissipates heat from an electronic component such as a semiconductor device that generates a large amount of heat in a relatively short time, and a method for manufacturing the same.

Conventionally, an example of a heat sink for an electronic component has been disclosed in which the vertical cross-sectional shape of the column is the same in each cross section in the longitudinal direction of the column, and a pin-shaped fin is provided on the side of the column (see, for example, Patent Document 1). ). In addition, an example of a heat dissipation structure for a semiconductor element that indirectly cools an electronic component using a refrigerant is disclosed (see, for example, Patent Document 2).
JP 2001-326307 A JP 2001-168256 A

However, in order to enhance the cooling effect of the heat sink for electronic parts disclosed in Patent Document 1, it is necessary to increase the number of pin-shaped fins or to secure a large surface area for heat dissipation. In this case, there is a problem that the heat sink itself becomes large.
Even if only the heat sink is air-cooled, there is a limit to the speed at which heat can be dissipated into the atmosphere. That is, the amount of heat that can be absorbed from the electronic component is approximately equal to the amount of heat that can be dissipated into the atmosphere. Therefore, there is a problem that heat cannot be absorbed from the electronic component beyond the amount of heat that can be dissipated into the atmosphere.

  In order to reduce the size of the heat sink and to absorb heat from the electronic component beyond the amount of heat that can be dissipated in the atmosphere, a refrigerant may be used as in Patent Document 2. However, in order to maintain the cooling effect, a mechanism for maintaining the temperature of the refrigerant (for example, a radiator shown in FIG. 9 of Patent Document 2) is required. Therefore, there is a problem that the configuration of the heat sink becomes complicated.

  The present invention has been made in view of the above points, and in order to enhance the cooling effect of an electronic component that generates a large amount of heat in a relatively short time, the size of the heat sink itself is suppressed and the electronic device has a simple configuration. An object of the present invention is to provide a heat sink for components and a method for manufacturing the same.

(1) Means for solving the problem (hereinafter, simply referred to as “solution means”) 1 is a heat sink for an electronic component, and includes a heat conduction member having a surface in contact with the electronic component, and the heat conduction. Except for the heat radiating fin joined to the member and the part to be joined to the heat conducting member, the heat radiating fin is integrated so as to cover almost the whole, and the heat stored in the heat radiating fin is absorbed and diffused into the atmosphere. The gist is to have a heat conductive resin.

The “electronic component” is arbitrary as long as it is a heating element that generates heat during energization or operation, and corresponds to a semiconductor device such as a transistor, IC, LSI, CPU, or the like.
The “thermal conducting member” and “radiating fin” may be any material as long as they are members that conduct or dissipate heat. That is, the material is not limited to metal and may be a resin or other material.
The interface between the “electronic component” and the “heat conducting member” may be configured to be in close contact with the heat conducting grease, or an insulating film is formed on the upper surface of the heat conducting member to further form a circuit for the electronic component. Also good.
The “thermal conductive resin” is arbitrary as long as it is a resin that absorbs heat and dissipates it into the atmosphere. For example, polyphenyl sulfide (PPS), liquid crystal polymer (LCP), polyether imide (PEI), polyether ether ketone (PEEK), polyamide (PA), polybutylene terephthalate (PBT), acrylonitrile butadiene styrene copolymer Resins such as (ABS) and acrylonitrile / styrene copolymer (AS) are applicable.
The interface between the “radiation fin” and the “thermal conductive resin” may be bonded with an adhesive that absorbs the difference in linear expansion coefficient when the materials are different, and the heat radiation fin with the organic thin film formed on the surface and the heat Bonding may be performed by causing interfacial bonding at the contact surface with the conductive resin.

  According to the solution 1, the heat generated in the electronic component is first transmitted to the heat conducting member and further to the heat radiating fins. Since these heat radiation fins are almost entirely covered and integrated with the heat conductive resin, they are absorbed faster than heat is released into the atmosphere. In other words, the heat conductive resin accumulates the amount of heat absorbed by subtracting the amount of heat released into the atmosphere, so that the heat absorption proceeds until the heat amount that can be accumulated as a whole is reached. Therefore, the electronic component can be cooled by absorbing heat until the amount of heat that can be accumulated in the entire heat conductive resin is reached. That is, it is optimal for cooling an electronic component that generates a large amount of heat in a relatively short time. Moreover, since it is not necessary to increase the size of the heat dissipating fins in order to enhance the cooling effect, the size of the heat sink itself can be suppressed. Furthermore, since it is sufficient to cover almost the entire radiating fin with the heat conductive resin, a simple configuration can be achieved. And since the site | part corresponded to heat conductive resin is formed with resin, it can reduce in weight compared with the case where it forms with a metal.

(2) Solution 2 is a heat sink for electronic components described in Solution 1, and the gist is that the cross-sectional shape of the radiation fin is formed in a comb shape or a ladder shape.

  According to Solution 2, by forming the cross-sectional shape of the radiating fin in a comb shape or a ladder shape, the area of the contact surface capable of conducting heat from the radiating fin to the heat conducting resin is increased, and the heat conducting resin is formed at the contact portion. Can absorb heat quickly. Also, when the comb-shaped or ladder-shaped tip is exposed without being covered with the heat conductive resin, heat can be directly dissipated from the exposed fins to the atmosphere, so that the heat dissipation efficiency Will improve.

(3) Solution means 3 is the heat sink for electronic components described in Solution means 1 or 2, and one or both of the heat conducting member and the heat radiating fin is formed of aluminum or an aluminum alloy. .

  According to Solution 3, aluminum or an aluminum alloy has high thermal conductivity and is lightweight (the specific gravity of aluminum is 2.7). If a heat conducting member or a heat radiating fin is formed with these, it is easy to absorb the heat of the electronic component, and a light heat sink can be configured.

(4) The solving means 4 is the heat sink for electronic parts described in any one of the solving means 1 to 3, and the gist is that the heat conducting member is brought into contact with the heat spreader of the electronic parts.

  According to the solution 4, a heat spreader made of a metal plate or the like is particularly attached to the package of the semiconductor device, and the heat conduction efficiency tends to be improved by cooling the semiconductor device through the heat spreader. Accordingly, the electronic component can be efficiently cooled by bringing the heat conducting member into contact with the heat spreader of the electronic component (more preferably, closely contacting).

(5) Solving means 5 is the heat sink for electronic components according to any one of solving means 1 to 4, wherein the heat conducting resin and the heat radiating fin are heat conducting heat radiating fins having an organic thin film formed on the surface. The gist is that the resin is inserted into the resin and bonded by causing interfacial bonding at the contact surface between the heat conductive resin and the heat radiation fin during molding.

  According to the solution means 5, the radiation fin which formed the organic thin film (for example, triazine dithiol etc.) in the surface previously is inserted with respect to heat conductive resin. In the mold, during bonding, an interface bond is caused at the contact surface between the heat conductive resin and the heat radiating fins to bond them. The bonding force due to the interface bonding is stronger than the bonding force for bonding the metal and the resin with an adhesive. Since metal and resin have different linear expansion coefficients, they may be peeled off by bonding with an adhesive, whereas they are not peeled because they are interface-bonded between metal and resin. Therefore, even if the heat sink itself becomes hot or cool, the radiating fin and the heat conductive resin do not peel off, and the electronic component can be reliably cooled.

  The heat sink for an electronic component according to the present invention enhances the cooling effect for an electronic component that generates a large amount of heat in a relatively short period of time, so that the size of the heat sink itself can be suppressed and the configuration can be simplified.

  The best mode for carrying out the present invention will be described with reference to the drawings.

  First, FIG. 1 shows an example of the appearance of the heat sink in a perspective view, and FIG. 2 shows an exploded perspective view. 1 and 2, the heat sink 10 for the electronic component 11 includes a heat conductive member 12, a heat radiating fin 13, a heat conductive resin 14, and the like. The electronic component 11 corresponds to a semiconductor device such as a transistor, IC, LSI, CPU, and the like. In this example, the heat spreader 11b is provided on the component main body 11a.

  The material of the heat conducting member 12 and the heat radiating fins 13 is arbitrary as long as they are members that conduct heat or dissipate heat. In this example, a metal (for example, aluminum or aluminum alloy) is processed and formed into a predetermined shape. The heat conducting member 12 has a surface that can come into contact with the electronic component 11 (particularly the heat spreader 11b), and the interface with the electronic component 11 is brought into close contact with, for example, heat conducting grease. The heat radiating fins 13 are joined to the heat conducting member 12 and have a cross-sectional shape, for example, a comb shape to facilitate heat dissipation (see particularly FIG. 2). The joining method is arbitrary, for example, soldering or brazing. The radiating fins 13 are exposed except for the part joined to the heat conducting member 12 as described above and the part covered with the heat conducting resin 14 as described later. Heat is directly diffused into the atmosphere from this exposed portion (for example, the tip portion 13a shown in the figure).

  The heat conductive resin 14 is integrated so as to cover almost the whole of the heat radiating fin 13 (that is, excluding the portion where the heat radiating fin 13 and the heat conductive member 12 are joined), and absorbs heat stored in the heat radiating fin 13. Vent into the atmosphere. The heat conductive resin 14 is optional as long as it absorbs heat and dissipates into the atmosphere. For example, “NT-783” manufactured by Idemitsu Kosan Co., Ltd. is suitable as polyphenyl sulfide (PPS). Although the heat conductive resin 14 shown in FIG. 2 appears to be composed of a plurality of cubes, the result of joining by insert molding so that the tip portion 13a is exposed is merely shown in an exploded perspective view.

  Although the joining method of the heat conductive resin 14 and the radiation fin 13 is arbitrary, for example, there is a joining method using a mold. Specifically, first, a process of forming an organic thin film (for example, triazine dithiol) on the surface of the radiation fin 13 is performed. Next, the heat radiating fins 13 on which the organic thin film is formed are inserted into the heat conductive resin 14. During the insert molding, the organic thin film acts on the contact surface between the heat conductive resin 14 and the heat radiating fin 13 to cause interface bonding, and both are joined.

  A heat dissipation process when the electronic component 11 generates heat using the heat sink 10 configured as described above will be described with reference to FIGS. First, when the electronic component 11 is operated by supplying power (voltage or current) or passing a signal, the electronic component 11 itself becomes hot as shown in FIG. Thus, the heat generated in the electronic component 11 is transmitted to the heat conducting member 12 through the heat spreader 11b as shown in FIG. The heat transferred to the heat conducting member 12 is further transferred to the heat radiating fins 13 as shown in FIG. The heat transmitted to the radiation fin 13 is transmitted to the heat conductive resin 14 as shown in FIG. Since the heat radiating fins 13 are almost entirely covered and integrated by the heat conductive resin 14, they are absorbed faster than heat is radiated into the atmosphere. In other words, the heat conducting resin 14 accumulates the amount of heat absorbed by subtracting the amount of heat dissipated in the atmosphere, so that the heat absorption proceeds until the heat conducting resin 14 reaches the amount of heat that can be accumulated. Eventually, as shown in FIG. 4B, heat is dissipated into the atmosphere from the exposed portions of the heat conductive resin 14 and the radiation fins 13 (the tip portion 13a in this example).

  When a test for applying heat of 100 [W] to the electronic component 11 for 300 seconds to generate heat is performed, the maximum temperature of the heat spreader 11b is as shown in FIG. In FIG. 5, in order from the left side, a heat sink (structure α) in which the portions corresponding to the heat radiation fins 13 and the heat conductive resin 14 (that is, a rectangular parallelepiped shape) are made of metal, and the heat sink 10 shown in FIG. The maximum temperature corresponding to each of the comb shape (structure β) and the heat sink 20 shown in FIG. 6 described later (the cross-sectional shape of the radiation fin 21 is a ladder shape; structure γ) is represented by a bar graph.

The maximum temperature of the structure α is 120 [° C.], whereas the maximum temperature of the structure β is 125 [° C.], and the maximum temperature of the structure γ is 115 [° C.]. If the heat radiating fins are made of only metal (for example, aluminum die cast), the heat conduction loss from the heat radiating fins 13 to the heat conductive resin 14 that may occur in the structure β is reduced, so that the maximum temperature is considered to be suppressed. However, when the heat dissipating fin having the structure α is formed by a mold, only a durability performance of about 100,000 shots can be obtained.
On the other hand, when the structure β (heat sink 10) is produced, when the heat dissipating fins 13 are inserted into the heat conductive resin 14 in the mold, durability performance of about 600,000 to 1,000,000 shots can be obtained. . That is, since the number of structures β can be made six times or more with a single-sided mold, the overall production cost can be kept lower than that of the structure α.

According to the embodiment described above, the following effects can be obtained.
(1) The heat sink 10 for the electronic component 11 is configured to include a heat conductive member 12, a heat radiating fin 13, and a heat conductive resin 14 (see FIG. 1). According to this configuration, the heat generated in the electronic component 11 is first transmitted to the heat conducting member 12 and further transferred to the heat radiating fins 13. Since the heat radiating fins 13 are substantially covered and integrated by the heat conductive resin 14 except for the joining portion, the heat radiating fins 13 are absorbed faster than heat is released into the atmosphere. In other words, since the heat conductive resin 14 accumulates the amount of heat absorbed by subtracting the amount of heat dissipated into the atmosphere, the heat absorption proceeds until the heat amount that can be accumulated as a whole is reached. Therefore, the electronic component 11 can be cooled by heat absorption until the amount of heat that can be accumulated in the entire heat conductive resin 14 is reached. That is, it is optimal for cooling the electronic component 11 that generates a large amount of heat in a relatively short time. Moreover, since it is not necessary to enlarge the radiation fin 13 in order to enhance the cooling effect, the size of the heat sink 10 itself can be suppressed. Furthermore, since it is sufficient to cover almost the entire heat radiation fin 13 with the heat conductive resin 14, a simple configuration can be achieved. And since the site | part corresponded to the heat conductive resin 14 is formed with resin, it can reduce in weight (about 10% by weight) compared with the case where it forms with a metal.
In the example of FIG. 1, one electronic component 11 is cooled, but a plurality of electronic components 11 may be cooled. As the number increases, it is necessary to increase the elements constituting the heat sink 10 (the heat conducting member 12, the heat radiation fin 13, the heat conducting resin 14, etc.).

(2) The cross-sectional shape of the radiation fin 13 was formed in a comb shape (see FIG. 2). According to this configuration, the area of the contact surface that can conduct heat from the radiation fins 13 to the heat conductive resin 14 is increased, and the heat conductive resin 14 can quickly absorb heat. Further, since the comb-shaped tip portion 13a is exposed without being covered with the heat conductive resin 14, heat can be directly dissipated from the radiation fins 13 in the exposed portion to the atmosphere, so that the heat radiation efficiency is improved. .

(3) Both the heat conducting member 12 and the heat radiating fins 13 are made of aluminum or an aluminum alloy. According to this configuration, it is easy to absorb the heat of the electronic component 11, and the light heat sink 10 can be configured.

(4) The heat conducting member 12 is configured to be in close contact with the heat spreader 11b of the electronic component 11 (see FIG. 1). According to this configuration, the electronic component 11 (that is, the component main body 11a as a semiconductor device) can be efficiently cooled. In addition, it is possible to cool the heat conducting member 12 as a configuration in which the heat conducting member 12 is brought into contact with the heat spreader 11 b of the electronic component 11.

(5) The heat conductive resin 14 and the heat radiating fin 13 are formed by inserting a heat radiating fin 13 having an organic thin film formed on the surface thereof into the heat conductive resin 14, and a contact surface between the heat conductive resin 14 and the heat radiating fin 13 during molding. In this configuration, the bonding is performed by causing interfacial bonding. The bond strength of the interface bond by this configuration is stronger than the bond force that bonds the metal and the resin with an adhesive. Therefore, even if the heat sink 10 itself becomes hot or cool, the radiating fins 13 and the heat conductive resin 14 do not peel off, and the electronic component 11 can be reliably cooled.

[Other Embodiments]
Although the best mode for carrying out the present invention has been described above, the present invention is not limited to this mode. In other words, various forms can be implemented without departing from the scope of the present invention. For example, the following forms may be realized.

(1) In embodiment mentioned above, the cross-sectional shape of the radiation fin 13 was formed in the comb shape (refer FIG. 2). Instead of this form, the cross-sectional shape of the radiating fin 13 may be formed in a ladder shape, and other shapes that increase the area of the contact surface that can conduct heat from the radiating fin 13 (for example, a large number such as Kenzan) You may form in the shape provided with the acicular part etc.).

  An example of the former is shown in FIG. The heat sink 20 shown in FIG. 6 includes a heat conductive member 12, a heat radiating fin 21, a heat conductive resin 14, and the like. The difference from the heat sink 10 shown in FIG. 1 is the following two points. First, the radiation fins 21 are formed in a shape different from that of the radiation fins 13. Secondly, in order to cool a plurality of (two in the example of FIG. 6) electronic components 11, the area of the planar shape of the heat conducting member 12 and the like is increased. By forming the cross-sectional shape of the radiating fins 21 in a ladder shape, the area of the contact surface that can conduct heat to the heat conducting resin 14 increases, and the heat conducting resin 14 can quickly absorb heat. Further, the portion exposed without being covered with the heat conductive resin 14 (corresponding to the lower surface portion of the heat radiation fin 21 in FIG. 6) can radiate heat directly from the exposed portion to the atmosphere to improve the heat radiation efficiency. Due to such factors, the heat sink 20 corresponding to the structure γ shown in FIG. 6 has a maximum temperature lower than those of the other structures α and β when power is applied to one electronic component 11 to generate heat. It appears as 115 [° C.].

(2) In the above-described embodiment, both the heat conducting member 12 and the heat radiation fin 13 are formed of aluminum or an aluminum alloy. Instead of this form, only one of the heat conducting member 12 and the heat radiating fin 13 may be formed of aluminum or an aluminum alloy, or may be formed of another member that conducts heat or dissipates heat. The other member is not limited to a metal, and may be a resin or other material. In any case, heat is transmitted from the heat sink 10 to the heat conductive resin 14 through the heat conductive member 12 and the heat radiating fins 13, and is radiated. Therefore, the same effect as the above-described embodiment can be obtained.

(3) In the above-described embodiment, the interface between the electronic component 11 (specifically, the heat spreader 11b) and the heat conducting member 12 is configured to be in close contact using heat conducting grease (see FIG. 1). Instead of this form, an insulating film may be formed on the upper surface of the heat conducting member 12, and a circuit of the electronic component 11 may be formed (that is, an integrated structure). Since this configuration is the same as that shown in FIG. 1, the same effects as those of the above-described embodiment can be obtained.

(4) In the above-described embodiment, the heat conductive resin 14 is formed using polyphenyl sulfide (PPS). Instead of this form, the heat conductive resin 14 may be formed using another resin that absorbs heat and diffuses it into the atmosphere. Examples of the other resin include liquid crystal polymer (LCP), polyetherimide (PEI), polyetheretherketone (PEEK), polyamide (PA), polybutylene terephthalate (PBT), acrylonitrile / butadiene / styrene copolymer. (ABS), acrylonitrile / styrene copolymer (AS), and the like are applicable. Even when the heat conductive resin 14 is formed using another resin, heat is absorbed from the radiating fins 13 and released into the atmosphere, so that the same effect as the above-described embodiment can be obtained.

(5) In the above-described embodiment, the heat dissipating fins 13 and the heat conductive resin 14 are configured to be joined by causing interfacial bonding in the mold. It replaces with this form, and it is good also as a structure joined by adhere | attaching using the adhesive agent which absorbs the difference of a linear expansion coefficient. Although the bonding force is inferior to the interface bonding, the heat radiation fins 13 and the heat conductive resin 14 are difficult to peel off, and the electronic component 11 can be reliably cooled.

It is a perspective view showing the example of appearance of a heat sink. It is a disassembled perspective view explaining the structural example of a heat sink. It is a figure explaining the heat dissipation process when an electronic component heat | fever-generates. It is a figure explaining the heat dissipation process following FIG. It is a figure explaining the maximum temperature of a heat spreader. It is a perspective view showing the other structural example of a heat sink.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10,20 Heat sink 11 Electronic component 11a Component main body 11b Heat spreader 12 Thermal conductive member 13, 21 Radiation fin 13a Tip part 14 Thermal conductive resin

Claims (5)

A heat conducting member having a surface in contact with the electronic component;
Radiating fins joined to the heat conducting member;
For an electronic component having a heat conductive resin that covers and integrates substantially the whole of the heat radiating fin except for a portion to be joined to the heat conductive member, and absorbs heat stored in the heat radiating fin and dissipates it in the atmosphere. heatsink. The heat sink for electronic components according to claim 1,
A heat sink for electronic components in which the cross-sectional shape of the heat dissipating fin is formed in a comb shape or a ladder shape. A heat sink for an electronic component according to claim 1 or 2,
One or both of the heat conduction member and the heat radiation fin is a heat sink for electronic parts formed of aluminum or an aluminum alloy. A heat sink for an electronic component according to any one of claims 1 to 3,
The heat conducting member is a heat sink for electronic components that is brought into contact with the heat spreader of the electronic component. A heat sink for an electronic component according to any one of claims 1 to 4,
Thermally conductive resin and radiating fins are electrons that are bonded to each other by forming an interface thin film at the contact surface between the thermal conductive resin and the radiating fin during molding by inserting a radiating fin with an organic thin film on the surface into the thermal conductive resin. Heat sink for parts.