CN1114338C - Method of making heat sink for printed circuit board and heat sink - Google Patents

Abstract

The assembly of the heat sink and the printed circuit board is made by mounting a heat exchange member on the heat sink, the heat exchange member being in heat exchange contact with and passing through the heat sink. After the circuit board and the heat sink are fixed in their spaced relative positions and the heat exchange member and the electronic component on the circuit board are aligned, a curable thermally conductive compound is injected through the hole in the heat exchange member and adheres to the electronic component. The heat sink is removable from the heat exchange member to expose the component-mounted side of the circuit board for maintenance or repair. The heat sink can then be reinstalled in its place in the assembly.

Description

Method of making heat sink for printed circuit board and heat sink

The present invention relates to a method of making a heat sink assembly for a printed circuit board and to a heat sink assembly.

In the construction of printed circuit boards containing electronic components, the components used generate heat, and heat dissipation is required to prevent overheating, which can lead to damage of one or more components. Generally, heat sinks are used to dissipate heat. For efficient heat exchange, it is often considered necessary to attach the heat sink tightly directly to the printed circuit board. But this creates a problem: It may be necessary to disassemble a heat sink assembly for a printed circuit board for inspection, improvement, or maintenance, and separating the board from the heat sink without consequent damage to one or more components in the assembly is actually impossible.

In other proposed configurations, the heat sink is mounted on the same side of the printed circuit board as the electronic components, such that the components are located between the circuit board and the heat sink. Heat is transferred from the electronic components to the heat sink through the heat transfer medium compound. Here again there is the issue of dismantling the parts, which is required for various reasons. Also, if the compound is added in place prior to part assembly, it may not create a satisfactory thermal connection between adjacent surfaces to improve thermal conductivity. The latter assembly method is also laborious and time consuming. Examples of such structures can be found in US Patent Nos. 4,849,856 and 4,914,551.

In U.S. Application Serial No. 08/133,396, filed October 9, 1993 in the name of R. Katchmar, a structure is described in which heat is diffused from electronic components mounted on the circuit board to the entire printed circuit board and then The heat is dissipated through the jumper extending from the circuit board to the heat sink. In this setup, the electronic component is bonded to the printed circuit board with a thermally conductive compound that flows into the gap between the component and the heat sink, and the thermal compound then cures in place.

The present invention seeks to provide a method of forming a heat sink assembly for a printed circuit board which minimizes the above-mentioned problems.

The invention provides a method for manufacturing a heat sink structure assembly for a printed circuit board, comprising: forming a structure including a printed circuit board and electronic components mounted on a first surface of the printed circuit board; forming a heat sink structure , which has a hole passing through the heat sink structure; the printed circuit board structure and the heat sink structure are relatively placed, so that the first surface of the heat sink structure and the printed circuit board structure face and are separated from it, and the axis of the hole is approximately Extends toward the electronic component; creates a thermal conduction path from the heat sink structure to the printed circuit board structure by allowing a flowable thermally conductive material or compound to flow through the holes to fill the gaps remaining between the heat sink structure and the printed circuit board structure In the gap area between them, it is in thermal contact with it and aligned with the electronic components.

By using the method of the present invention, heat sink structures for printed circuit boards are assembled together in their relative positions before the thermally conductive compound is cast in place. Because the thermally conductive material or compound flows between the two structures after they are assembled together, the flowing material tightly contacts the surfaces of the two structures and heat is conducted between them, maximizing the heat transfer efficiency of the assembly. Also, making the assembly this way is convenient because the thermally conductive material is not placed on top of one structure before the other is fixed in place, avoiding any slow and untidy assembly steps. On the other hand, since the flowable material is caused to flow through the holes in the fin structure, the method is particularly suitable for using injection equipment, ie, having injection nozzles placed in the holes to inject material between the two structures. Therefore, the process step of fixing the thermally conductive material in the correct position can be done easily, quickly, efficiently and cleanly. Formed assemblies of heat sink structures for printed circuit boards are known to optimize heat dissipation from components mounted on the printed circuit board, and are thus particularly suitable for heat dissipation from printed circuit board structures in which the resulting Heat, if not conducted away with proper efficiency, can cause electronic components to malfunction and fail.

In the method according to the invention, after the process step, the heat sink structure can be either facing the first side of the printed circuit board or the second side thereof. If the heat sink structure is facing the first side of the printed circuit board, a thermally conductive material is flowed through the holes to fill the gap area between the heat sink structure and the electronic component itself. The thermally conductive material is thus in direct thermally conductive contact with the electronic component closest to the heat sink structure. Conversely, if the heat sink structure is facing the second side of the printed circuit board, the thermally conductive material flowing through the holes fills the gap area between the heat sink structure and the printed circuit board itself. In order to maximize heat transfer from the electronic components, there must be some path of heat transfer from the thermally conductive material in the gap region through the circuit board to the electronic components. This can advantageously be produced by causing the heat-conducting material to flow from the gap region through at least one aperture in the printed circuit board onto the electronic component and preferably make thermally conductive contact with the electronic component. In an embodiment, a first glob of thermally conductive material is flowed between the first side of the printed circuit board and the electronic component, and a second glob of thermally conductive material is flowed between the second side of the printed circuit board and the heat sink structure. This is conveniently done by inserting the injection device through a hole in the heat sink structure into a small hole in the printed circuit board, injecting a first glob of material between the first side of the circuit board and the component, and then allowing the injection device to pass from the The small hole exits so that it is only inserted into the hole of the heat sink structure, thereby allowing the second mass of material to flow between the second side of the circuit board and the heat sink structure. In another method, a first glob of material flows between the first side of the circuit board and the electronic component when the two structures are separated from each other, and then a second glob of material flows through the hole to fill the hole after the structures are assembled together. Fill the gap between the circuit board and the heat sink structure.

The method of the present invention can advantageously be used to remove the heat sink itself from the printed circuit board structure, thereby allowing immediate access to the circuit board or electronic components for repair, replacement or inspection. This is achieved by the heat sink structure comprising a heat sink and heat exchange elements mounted thermally conductively on the heat sink. The heat exchanging part and the printed circuit board structure are separated from and opposed to, while facing the electronic components. A settable thermally conductive material is distributed between and in thermally conductive contact with the printed circuit board structure and the heat exchange component. In this preferred method, the thermally conductive material is adhesive to provide adhesion between the printed circuit board structure and the heat exchange component, and a heat sink removal mechanism is provided to allow the heat sink to be removed from the heat exchange component while the heat The exchange components remain mounted on the printed circuit board structure through the adhesion of the thermally conductive material. The fin removal means may conveniently comprise a heat exchange mount in a threaded arrangement. The threaded device includes threads on the heat exchanging part and a nut, which can be screwed into the end of the side of the heat sink away from the printed circuit board. Removal of the nuts then allows the heat sink to be removed from the assembly of the printed circuit board and the heat exchanging components mounted thereon by the heat conducting material. The electronic components are thus immediately accessible as described above. On the other hand, when the nut is not used, the threaded means allows the heat exchanging element to rotate in the fin. In this function, the heat exchange component has a brittle zone, or the heat conducting material itself is brittle. Thus, due to the rotation of a portion of the heat exchanging element in the aperture, the frangible area of the heat exchanging element or the friable thermally conductive material ruptures, thereby causing the heat sink to be detached from the printed circuit board.

The invention is particularly useful in situations where there are many electronic components distributed between heat sinks for printed circuit boards, as is often the case. This often creates a problem since PCBs are not perfectly flat, plus electronic components come in different shapes and heights. That is, it is difficult to thermally conductively connect each component directly to the heat sink with a thermally conductive material while minimizing stress on the printed circuit board, electronic component, or component terminal pins. This problem becomes more serious during temperature fluctuations caused by the environment in which the device is used. This method minimizes these problems by placing the electronic components between the circuit board and the heat sink, where the gap between the heat sink and the electronic components can vary from component to component, in this case through multiple holes connected to each component Injected thermally conductive material fills each gap area necessary to form a thermally conductive shunt from the component to the heat sink.

In addition, when the components are mounted on the first side of the board and away from the heat sink, the thermally conductive compound flows virtually completely through the board and into contact with the electronic components. The solder joints from the pins to the board create minimal stress while providing a low thermal resistance path to the heat sink. With this arrangement, susceptibility to structural damage due to circuit board deformation or spacing changes is also minimized. In particular, the means for mounting electronic components on the side of the circuit board away from the heat sink is particularly suitable for heat dissipation of electronic components having their pins connected to the printed circuit board by means of solder ball arrays.

According to another aspect of the present invention, there is provided an assembly of a heat sink structure for a printed circuit board, comprising: a structure of a printed circuit board and electronic components mounted on a first side of the printed circuit board; a heat sink structure with a hole through it; the two structures are placed face to face and separated so that the hole extends generally toward the electronic component; and a thermally conductive material that flows through the hole and is distributed between the two structures, filling the transverse The gap region extends through the hole and is in thermally conductive contact with the two structures and is aligned with the electronic components.

Embodiments of the invention will now be described by way of example with reference to the accompanying drawings, in which:

Figures 1, 2 and 3 are cross-sectional views showing three different stages in the fabrication of an assembly of a heat sink structure for a printed circuit board according to a first embodiment;

Figure 4 is a view similar to the components of the first embodiment of Figures 1 to 3 . Shows the heat sink being removed from the assembly to allow access to the printed circuit board and electronic components;

Figure 5 is a view similar to Figure 3 of an assembly of a printed circuit board and a heat exchange structure according to a second embodiment;

Figure 6 is a view similar to Figure 5, showing two assemblies according to a second embodiment brought together to form a complete assembly with a housing;

Figure 7 is a view similar to Figure 6, showing the structure of Figure 6 with a cooling fin removed;

Figures 8 and 9 are views similar to Figures 3 and 4, with changes to the first embodiment;

Figure 10 is a view similar to Figure 4, with another variation of the first embodiment;

Figures 11 and 12 show two different stages in the fabrication of an assembly of a heat sink structure for a printed circuit board according to a third embodiment;

Figure 13 shows the completed components of the third embodiment;

Figure 14 relates to another method as shown in Figures 11 and 12, showing the first step of two different stages in the fabrication of the component of the third embodiment;

Figure 15 is a view similar to Figure 13, a fourth embodiment;

Figure 16 is a cross-sectional view of an assembly according to a fifth embodiment;

Figure 17 is a section view, on a larger scale, of a part of an assembly according to a fifth embodiment;

Fig. 18 is a cross-sectional view of the assembly part taken along line XVIII-XVIII in Fig. 17;

Figure 19 is a view similar to Figure 18, with a variation on the fifth embodiment; and

Fig. 20 is a sectional view through the sixth embodiment.

As shown in FIG. 1, in a first embodiment, the heat sink structure includes a heat sink 10 having a straight planar portion 12 having a heat sink 14 integral therewith on one side thereof. The fin structure also includes a number of heat exchanging elements 16 (only one shown), each heat exchanging element comprising a wide portion 18 integral with a narrow portion in the form of a cylindrical rod 20 threaded on the outwardly free end. . Each component 16 passes through each hole 22 in the heat sink and is assembled on the heat sink by fixing it with a connecting device in the form of a nut 24 on the side of the heat sink on the plane part 12, and the nut 24 is screwed into the heat sink. In the thread of the rod 20. In this way the wide part is fixed and has a close thermal contact with the heat sink. If desired, a thermally conductive oil film can be applied between the wide portion 18 and the cooling fins, dry contact is generally sufficient.

In the first embodiment there is also a printed circuit board (FIG. 2). On one side of the printed circuit board is mounted a number of electronic components 28 which are connected via pins 30 to the circuitry of the board.

It is intended that the printed circuit board structure including the components 28 be assembled to the heat sink so that heat is transferred directly from the components 28 through the heat exchange components into the heat sink. For this reason, the circuit board and the heat sink are placed according to their relative positions as shown in FIG. 2 , wherein the heat sink 6 is fixed by a positioning member 32 to have a certain distance from the printed circuit board. And opposite to it, the positioning member 32 is fixed on the printed circuit board by fixing bolts 34 . The heat exchanging components 16 are pre-mounted on the heat sink so that when assembled to the printed circuit board, each component 16 is fixed with its wide portion 18 separated from and directly opposite the corresponding respective electronic component 28 . This is clearly shown in FIG. 2 .

To complete the assembly, an adhesive and curable thermally conductive adhesive material may be dispensed in the gap area between each electronic component 28 and its corresponding wide portion 18 of the heat exchange member 16 . The material may be a thermally conductive elastic viscous material with a low modulus of elasticity, preferably less than 500 psi. In order to put the heat-conducting medium into each gap, the part 16 has a hole 36 passing from one end of the part to the other, ie in the axial direction of the rod 20 and through the wide part 18, as shown in FIG. 2 . When the heat sink and the printed circuit board are assembled at the stage shown in Figure 2, the thermally conductive material is injected from the outside of the heat sink through each hole to fill and fill the gap area between the wide portion and the electronic component 28, as shown in Figure 2. As shown at 38 in 3, it is also possible to closely connect the surfaces on both sides of the gap to form an effective heat exchange medium from element 28 into component 16. By injecting material 38 into the gap area after the heat sink structure for printed circuit boards is assembled, the thermally conductive material can effectively fix the wide portion 18 of the component 16 on the electronic component 28 after curing, as shown in Figure 3, the material Gradually flow over opposing surfaces to bring them into close contact to ensure the best possible thermal conduction from each component to the heat sink. Also, the injection process is clean, efficient and time-saving.

In the use of the completed assembly 40 of FIG. 3, any heat generated by the electronic components is transferred with the highest efficiency through the thermally conductive adhesive 38 directly into the wide portion 18 of the component 16, and through the heat conduction of the wide portion and the inner surface of the heat sink. Sexual contact is passed into the heat sink 10. When it is necessary to contact the side of the printed circuit board where the electronic components are housed, the following things are simple. By taking off the nut 24, the heat sink and the structure of the printed circuit board are loosened, so that the heat sink can be removed from the circuit board. The components 28 and circuitry on the circuit board are thereby exposed for the desired purpose. This specific step is shown in FIG. 4, from which it can be seen that each component 16 remains fixed to its respective electronic component 28 with the thermally conductive material 38 therebetween. Thus, if the structure initially consists essentially of two subassemblies, one of which consists of fins to which heat exchanging components 16 are secured, after the complete assembly 40 has been formed, then by removing the fins from each component 16 It is necessary to remove the heat exchange assembly. After taking proper measures for PCB or any electronic component, the next thing is easy. To complete the assembly by refitting the heat sink, the holes 22 are simply aligned with the corresponding rods 20, the heat sink is moved back to its assembled position, as shown in Figure 3, and the retaining nut 24 is then fitted.

As can be seen from the above embodiments, in the assembly formation of heat sinks for printed circuit boards, the thermally conductive material in a fluid state can be easily, quickly and cleanly added through the injection process. Also, removing the heat sink to make the printed circuit board or electronic components accessible is extremely simple and can be done quickly without causing any damage to any part of the assembly. Subsequent replacement of the printed circuit board to change components is also a simple matter. In addition, despite the complete thermal contact between each electronic component 28 and the heat sink 40 through the thermally conductive material 38, and the differences in the spacing between the electronic components and the heat sink, only Minimal stress. For example, stresses caused by differences in temperature expansion between the heat sink and the printed circuit board. It can be seen that the spacing between the part 16 and the element 28 can vary widely, but this variation is insignificant since the gap area formed between the part 16 and the corresponding element 28 can be easily filled with material 38 , while ensuring thermally conductive contact. Minimal stresses are generated in the assembly and thus also between the heat sink and the printed circuit board, which may cause some problems after the assembly is formed.

Transverse stresses (which can be caused by temperature changes) are minimized by using a heat sink containing a material with a temperature expansion coefficient properly matched to that of the printed circuit board, preferably within ±3 x 10 ^-6 /°C. For example, copper alloys, or composites or alloys of aluminum and silicon, which are inexpensive but perform well.

In the following additional embodiments and variations, parts similar to those of the first embodiment have the same reference numerals.

As shown in FIG. 5, in the second embodiment, a printed circuit board 26 and a plurality of electronic components 28 together form a printed circuit board structure, as described in the first embodiment. The fins 52 have a planar portion 54 similar to that of the first embodiment, and integral parallel split fins 56 extending from one side of the planar portion 54 . In addition, the heat sink also incorporates the same components 16 as in the first embodiment, these components being positioned so that in the complete assembly 50 the wide portion 18 of the component and the electronic component 28 are separated and opposed. Thermally conductive material 38 is distributed between the electronic components and component 16 using the method described in the first embodiment. Assembly 50 differs from that of the first embodiment in that fins 52 have side walls 58 extending outwardly from one side of the plane of portion 54 at the four edges of planar portion 54 . These sidewalls have outward mating flats 60 which can fit the edge regions of the printed circuit board 26 to hold the printed circuit board away from the flat portion of the heat sink before the material 38 is injected between the component 28 and the component 16. 54 has a fixed distance.

Assembly 50 is particularly useful when combined with an assembly 50 formed in a similar manner, as shown in FIG. Enclosure that encloses the printed circuit board structure. As shown in Figure 6, the two side walls 58 are equipped with means to assemble the side walls together, this means in this example is in the form of an outwardly protruding flange 62, which is positioned against the wall for assembly. Together, the elongated gasket 64 may be held in place by a clamp (not shown) or threaded structure. As can be seen in FIG. 6, while each assembly 50 has printed circuit boards mounted thereon, the printed circuit boards in the completed assembly are separated from each other and the electronic components 28 are secured to the component 16 by the thermally conductive material 38.

As shown in Figure 7, if it is desired to remove any of the fins 52, the associated nut 24 is removed from the component 16 so that the fins can be removed. In this case, as shown in FIG. 7, the corresponding printed circuit board 12 with the electronic components 28 mounted thereon is exposed for any desired purpose. In this particular example, the printed circuit board remains in its "in-use" position, held there by any electrical conductors extending thereto. To install a heat sink that has been removed, simply align the holes 22 with the rods 20 and move the circuit board over the rods and attach it to the circuit board 12 . The nut 24 is then screwed on to complete the assembly, and the two heat sinks 52 are then realigned so that they are reassembled to form the housing.

It is not necessary to separate the heat sink from the printed circuit board in the manner described in the above embodiments. For example, in a first variation of the first embodiment shown in Figures 8 and 9, the heat exchange member 70 is similar to the heat exchange member 16 described above except that there is a narrower portion at the junction of the narrower portion 72 and wider portion 74 of the member. The neck 76 is thinned to make it easy to break. Figure 8 shows the complete assembly of this variation, which differs from the previous embodiment in that the narrow portion 72 is threaded into a threaded hole 78 in the flat portion 12 of the fin. In order to remove the heat sink 10, a screwdriver is inserted into the tail groove on the narrow portion 72 of the heat exchange component, and the narrow portion is turned in the threaded hole. Upon rotation the neck 76 breaks immediately, while the wide part 74 of the part remains in place by the adhesive 38, so that the narrow part 72 is separated, as shown in Figure 9, and the heat sink can be removed. Obviously, disassembling the printed circuit board assembly with this type of device, when repositioning, must have the electronic components 28 and the wide part of the heat exchanging part to reassemble, as well as the heat exchanging part 70 and the heat sink 10 together. reset.

In another variation of the first embodiment, as shown in FIG. 10, the cured thermally conductive material 38 itself can be fragile, so that when a screwdriver is inserted into the tail groove 80 of the heat exchange component 70, the thermal compound 38 breaks and can The heat sink is removed together with the entire heat exchange unit.

It is also within the scope of the invention for one or more electronic components to be mounted on the side of the printed circuit board remote from the heat sink, as shown in the embodiments now to be described.

For example, in a third embodiment shown in Figures 11, 12 and 13, a heat sink 10 has one or more heat exchanging elements attached thereto in the manner described in the first embodiment. In the third embodiment only one such component is shown. However, the positions of the printed circuit board structures are reversed such that the electronic components 28 and the heat sink are separated by the printed circuit board 26 .

FIG. 11 shows the separation of the heat sink and the printed circuit board during the first stage of application of the curable thermally conductive material 38 . As can be seen in FIG. 11 , there are a number of small holes 82 through the printed circuit board to the underside of each electronic component 28 . The substantially central aperture 84 is generally aligned with the aperture 36 through each associated heat exchange component 16 . Thermally conductive material 38 is added in two clumps 38a and 38b (see Figure 12). In each case, the first mass 38a is added by inserting an injection device through the hole 36 in the form of an injection nozzle 86 long enough to extend into the corresponding aperture 84, as shown in FIG. 11. The mass of material 38 a is then injected into the gap region between the printed circuit board 26 and the electronic component 28 . The mass of material gradually moves under the component 28 and tightly bonds the surface of the component and the surface of the printed circuit board. As shown in FIG. 12 , the nozzle 86 is then retracted to a position where its outlet end is located in the bore 36 . The second mass 38b of thermally conductive material 38 is then injected into the gap area between the printed circuit board and the wide portion 18 of the heat exchanging member 6 so as to closely connect the reverse side of the printed circuit board and the end face of the wide portion 18 . During this process, aperture 84 should substantially fill material 38 . Additionally, Figure 13 shows the completed configuration of the assembly, wherein as shown to the right of aperture 84, apertures 82 should be at least partially filled with compound 38 from both sides of the circuit board, preferably the compound should be passed continuously through each aperture Holes 82 interconnect the two masses of material 38a and 38b. On the other hand, as shown on the left side of Figure 13, the small holes 82 can be pre-filled with solder 88 or some other thermally conductive material, such as copper, to help transfer heat from the ball 38a to the ball 38b, and then through the heat exchange component 6 to the heat sink. in the film.

In an alternative method of forming the structure of FIG. 13, as shown in FIG. 14, each mass 38a is secured between its associated electronic component 28 and the printed circuit board 26 before the printed circuit board structure is attached to the heat sink structure. . In this method, the injection nozzle 86 is pierced into the small hole 84 and the mass of material 38 is injected into the interstitial region under the element 28 . When all the balls of material 38a are in place, the printed circuit board structure with the balls of material 38a is complete and mounted on the printed circuit board structure. The mass of material 38b is then formed between the printed circuit board and the heat sink 12 using the method described above with reference to FIG. 12 . The completed structure is again shown in Figure 13.

In a fourth embodiment shown in FIG. 15, there is a substantially larger aperture 90 beneath each component 28 mounted on the printed circuit board 26. As shown in FIG. The aperture may be elongated or otherwise shaped such that it extends substantially under the contour of the element 28 concerned. After the heat sink structure and the printed circuit board structure are assembled together, the nozzle 86 is inserted into each hole 36, and by one injection operation, a whole mass of thermally conductive material 38 is injected into the end surface extending on the wide portion 18 of the heat exchange component. and the gap area between the opposite side of the associated electronic component 28. The mass of material 38 passes through the aperture 90 to form direct thermally conductive contact from the element to the wide portion 18 of the heat exchange component.

In all of the above embodiments, where the electronic components are located on the side of the printed circuit board remote from the heat sink, it was subsequently found that the likelihood of the printed circuit board bending due to temperature changes or localized thermal effects was practically minimized. In addition, there is minimal stress on the component solder joints at the lead ends of the printed circuit board.

When the electronic components are installed on the opposite side of the printed circuit board and the heat sink, this special device can be advantageously applied to dissipate heat from the electronic components, for example, for electronic components with a planar structure, the terminals of which are connected by a ball mesh array to the printed circuit board. For example, in the fifth embodiment shown in FIG. 16, the planar electronic component 92 is mounted on the side of the printed circuit board 26 facing away from the heat sink 10, and the positioning member 32 is fixed in place as described in the previous embodiments. For each component 92, the heat exchange member is again employed with its wide portion 18 facing the corresponding electronic component 92 with the printed circuit board 26 in between. As shown in FIG. 16, the thermally conductive material 38 fills the gap area between the circuit board and the wide portion of each heat exchanging component, and enters the small holes 94 in the printed circuit board. As shown in Figures 17 and 18, the holes 94 are in the form of vias with conductive traces 96 at the outer ends of the circuit board. Traces 96 are connected to terminals of the electronic component by solder balls 98 applied by known methods to form terminal connections. The holes 94 have an inner layer 100 of conductive material, such as copper, to connect each pin of the electronic component to a circuit in the circuit board. The viscous thermally conductive material 38 extends into each aperture 94 to make direct thermally conductive contact with the inner layer 100 to dissipate heat from the electronic components. Thermally conductive material may also be made to flow into the gap defined by 92,96.

In a variation as shown in Figure 19, additional small holes 102 pass through the printed circuit board between traces 96, and these small holes 102 are themselves filled with thermally conductive material 38 which also extends into and fills each electronic component 92 and the clearance between the printed circuit board.

The sixth embodiment shown in Figure 20 shows heat exchanging components mounted on heat sinks, either in the order shown or in reverse, to form a thermal connection to the printed circuit board, which is not essential to the invention, although these Parts may be preferred for easy disassembly of the completed assembly.

The sixth embodiment provides all of the best thermal conductivity characteristics of the preceding embodiments, wherein the heat sink structure includes a heat sink 110 formed with holes 112 aligned with the electronic components 28 mounted on the printed circuit board 26 . Thermally conductive material 38 is injected through holes 112 to fill the gap area between each component 28 and the opposing heat sink surface to transfer heat from the component directly to the heat sink.

Claims (25)

1. A method of making an assembly for a heat sink structure of a printed circuit board, comprising: forming a structure comprising a printed circuit board and electronic components mounted on a first side of the printed circuit board; Forming a heat sink structure with holes passing through the heat sink structure; Relatively place the printed circuit board structure and the heat sink structure, make the first surface of the heat sink structure face the printed circuit board structure and be separated from it, and make the axis of the hole generally extend toward the direction of the electronic component, and generate heat dissipation from the The thermal conduction path from the fin structure to the printed circuit board structure by allowing a flowable, settable thermally conductive material to flow through the holes to fill and remain in the gap area between the heat sink structure and the printed circuit board structure, And maintain thermal contact with it, and align with electronic components. 2. The method according to claim 1, comprising: arranging the printed circuit board structure and the heat sink structure relatively so that the first surface of the heat sink structure faces the first surface of the printed circuit board; and flowing a curable thermally conductive material through the holes to fill the gap between the heat sink structure and the electronic component, and to make thermally conductive contact with the electronic component. 3. The method according to claim 1, comprising: Relatively placing the printed circuit board structure and the heat sink structure so that the first surface of the heat sink structure and the second surface of the printed circuit board face each other and are separated by a certain distance; and flowing a thermally conductive material through the holes to fill a gap area between the heat sink structure and the printed circuit board structure, and from the gap area to the electronic component through at least one aperture in the printed circuit board. 4. The method of claim 3, comprising flowing the thermally conductive material through the aperture in the printed circuit board and into thermally conductive contact with the electronic component. 5. The method according to claim 1, comprising: Relatively placing the printed circuit board structure and the heat sink structure so that the first surface of the heat sink structure faces and is separated from the second surface of the printed circuit board; causing the first glob of thermally conductive material to flow between the first side of the printed circuit board and the electronic component, and to maintain thermally conductive contact with the electronic component; and allowing the second glob of thermally conductive material to flow through the aperture between the second side of the printed circuit board and the heat sink structure, and be in thermally conductive contact with the heat sink structure, and in thermally conductive contact with the first glob of material. 6. The method according to claim 5, comprising inserting the injection device into the aperture of the printed circuit board through the hole in the heat sink structure, and injecting the first glob of thermally conductive material between the first side of the printed circuit board and the electronic component ; and then flowing the second glob of material through the holes to fill the gap area between the heat sink structure and the second side of the printed circuit board. 7. The method according to claim 1, comprising: causing a first glob of thermally conductive material to flow between the first side of the printed circuit board and the electronic component and maintain thermally conductive contact with the electronic component when the printed circuit board structure and the heat sink structure are separated; and then assembling together the heat sink structure for the printed circuit board, followed by allowing a second mass of thermally conductive material to flow through the holes between the second side of the printed circuit board and the heat sink structure, and in thermally conductive contact with the heat sink structure , and in thermally conductive contact with the first mass of material. 8. The method according to claim 1, comprising: forming a plurality of electronic components mounted on the first side of the printed circuit board; forming a heat sink structure with a number of holes therethrough; arranging the circuit board structure and the heat sink structure relative to each other such that said aperture is generally axially toward an associated electronic component; and flowing the thermally conductive material through the holes in the heat sink structure to fill the gap area between the heat sink structure and the printed circuit board structure and to align with the electronic components. 9. The method according to claim 1, wherein the heat sink structure comprises a heat sink and a heat exchange component thermally mounted on the heat sink, the heat exchange component is separated from the printed circuit board structure and is opposite to it, and faces toward the electronic component. Direction, the method includes flowing a curable thermally conductive material into the gap area between the printed circuit board structure and the heat exchange component, and maintaining thermally conductive contact with the heat exchange component, the thermally conductive material is adhesive, and can be placed on the printed circuit board structure Adhesive force is generated between heat exchange components, and a cooling fin removal device is provided so that the heat sink can be removed from the heat exchange components, while the heat exchange components are adhered to the printed circuit board structure by thermally conductive material. 10. The method of claim 7, wherein a sidewall is formed on the heat sink structure, the method comprising abutting an edge region of the printed circuit board against a mating surface of the sidewall to determine prior to flowing the thermally conductive material through the hole. The position of the printed circuit board structure relative to the heat sink structure, and the determination of the distance between the two structures. 11. An assembly of a heat sink structure for a printed circuit board, comprising: A structure for a printed circuit board and electronic components mounted on a first side of the printed circuit board; a heat sink structure having holes therethrough; The two structures are placed face to face and separated such that the aperture extends generally in the direction of the electronic component; and a thermally conductive material that flows through the aperture to distribute between the two structures, fills the gap region extending through the aperture, and is in thermally conductive contact with the two structures, and is also aligned with the electronic component. 12. The assembly of claim 11, wherein the heat sink structure faces the first side of the printed circuit board, and the thermally conductive material is disposed between and in thermally conductive contact with the electronic component and the heat sink structure. 13. The assembly of claim 11, wherein the heat sink structure faces the second side of the printed circuit board, and the thermally conductive material extends through the aperture in the printed circuit board in thermally conductive contact with the electronic component. 14. The assembly of claim 11 , wherein the heat sink structure faces the second side of the printed circuit board, the thermally conductive material extends between and is in thermally conductive contact with the second side of the printed circuit board and the heat sink structure, and Extending between and in thermally conductive contact with the electronic component and the first side of the printed circuit board, the heat exchange material on one side of the circuit board is in thermally conductive relationship with the heat exchange material on the other side of the circuit board. 15. The assembly of claim 14, wherein the thermally conductive material extends through at least one aperture in the printed circuit board and interconnects the thermally conductive material on both sides of the circuit board. 16. The assembly of claim 14, wherein another thermally conductive material is located in at least one aperture of the printed circuit board and is in thermally conductive contact with the thermally conductive material on both sides of the circuit board. 17. The assembly according to claim 11, wherein the heat sink structure faces the second side of the printed circuit board, the terminal pins of the electronic components are connected to the lead ends of the printed circuit board through a solder ball grid array, and the thermally conductive material is on the heat sink structure. extending between and in thermally conductive contact with the second side of the printed circuit board, and the thermally conductive material extends into the apertures on the printed circuit board and is in thermally conductive relationship with the solder ball mesh array. 18. The assembly according to claim 11, wherein the heat sink structure comprises a heat sink and a heat exchange part passing through the heat sink and facing the electronic component, and the thermally conductive material has adhesiveness and is distributed between the printed circuit board structure and the heat exchange part The heat exchange part is formed with a hole, and the heat transfer material flows through the hole. The heat exchange part is glued to the printed circuit board structure by the heat transfer material and mounted on the heat sink, so that the heat sink can be from The heat exchange components are removed while the heat exchange components remain mounted on the printed circuit board structure by the thermally conductive material. 19. The assembly according to claim 18, wherein the heat exchanging member includes a wide portion and a narrow portion through which the hole passes, the heat exchanging member being mounted on the fin such that the narrow portion extends through the fin and the wide portion is in the One side of the heat sink faces the printed circuit board structure, and the thermally conductive material is distributed between the wide portion and the printed circuit board structure. 20. An assembly according to claim 19, wherein thread means are provided to attach the heat exchange element to the heat sink and to allow the heat sink to be detachable from the structure. 21. The assembly according to claim 20, wherein the narrow portion of the heat exchange member has an end away from the wide portion, and the screw means includes threads on the end and a screw threaded into the end on the second face of the cooling fin. cap. 22. An assembly according to claim 21, wherein the heat exchange member has a frangible area at the narrow portion, the heat exchange member being rotatable in the aperture of the heat sink to cause the heat exchange member to break while the narrow portion remains in the aperture, thereby enabling Make the heat sink removed. 23. The assembly of claim 18, wherein the thermally conductive material is brittle, and the heat exchanging member is rotatable in the aperture of the heat sink to cause the bond between the structure and the wide portion of the heat exchanging member to break, thereby enabling The fins are removed from the structure together with the heat exchange components. 24. The assembly of claim 19, wherein side walls are formed on the heat sink, the side walls having mating surfaces for abutting against edge regions of the printed circuit board when the heat sink is mounted in place according to the narrow portion. 25. The assembly of claim 10, wherein the heat sink forms part of a housing that completely encloses the printed circuit board structure.

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