CN112512201B

CN112512201B - Printed circuit board with embedded phase change heat dissipation device

Info

Publication number: CN112512201B
Application number: CN202011334130.0A
Authority: CN
Inventors: 陈博谦; 任远; 陈锦标; 许毅钦; 刘宁炀
Original assignee: Heshan Shituo Electronic Technology Co ltd
Current assignee: Heshan Shituo Electronic Technology Co ltd
Priority date: 2020-11-24
Filing date: 2020-11-24
Publication date: 2022-07-05
Anticipated expiration: 2040-11-24
Also published as: CN112512201A

Abstract

The invention provides a printed circuit board embedded with a phase change heat dissipation device, which comprises a first substrate, a second substrate, a first circuit positioned at the top of the first substrate, a bonding pad connected with the first circuit, the phase change heat dissipation device and a heat conduction part, wherein the first substrate is provided with a first surface and a second surface; the welding disc is used for welding a power device, a first base material below the welding disc is provided with a mounting hole for embedding the phase change heat dissipation device, and the phase change heat dissipation device is mounted in the mounting hole; the second substrate is provided with a plurality of through holes, the through holes are provided with heat conducting portions, and heat of the phase change heat dissipation device is suitable for being transmitted to the bottom of the second substrate along the heat conducting portions. The scheme of the invention can rapidly guide heat when the power device generates high Joule heat by instant high current, and utilizes the whole printed circuit board to assist in heat dissipation, so that the temperature of the power device is kept stable.

Description

Printed circuit board with embedded phase change heat dissipation device

Technical Field

The invention relates to the field of printed circuit boards, in particular to a printed circuit board with an embedded phase change heat dissipation device.

Background

Along with the smaller and more handy, more powerful, the performance of electronic system volume is more high-efficient, for satisfying the electric property ground of electronic product and constantly promoting, the PCB bears more and more passive and active electronic component. Large scale integration of components results in large power consumption, resulting in increased power density of electronic systems. If the heat cannot be dissipated smoothly, the junction temperature of the component will rise sharply, which seriously affects the reliability of the electronic device.

On the other hand, when the power of the power device is gradually increased, joule heat on the power transmission line on the circuit board due to the increase of the current becomes significant. Especially with higher currents, there is a need to reduce the package size, i.e. thinner and narrower conductors and finer interconnect circuit gaps, which will result in high heat generation in the electronic package and the interconnect system. At present, the problem of high joule heat generated by instant high current of a power device cannot be realized by the existing PCB heat dissipation scheme, so that faults are caused by instant temperature rise of a PCB.

Disclosure of Invention

In order to solve at least one of the above technical problems, the present invention provides a printed circuit board with an embedded phase change heat dissipation device to achieve the purpose of solving the technical problem of rapid heat dissipation. The purpose of the invention is realized by the following scheme:

a printed circuit board with an embedded phase-change heat dissipation device comprises a first base material, a second base material, a first circuit, a bonding pad, a phase-change heat dissipation device and a heat conduction part, wherein the first circuit is positioned at the top of the first base material; the welding disc is used for welding a power device, a first base material below the welding disc is provided with a mounting hole for embedding the phase change heat dissipation device, and the phase change heat dissipation device is mounted in the mounting hole; the second substrate is provided with a plurality of first through holes, the first through holes are provided with heat conducting portions, and heat of the phase change heat dissipation device is suitable for being transmitted to the bottom of the second substrate along the heat conducting portions.

Further, the phase change heat dissipation device is a temperature equalization plate.

Further, the heat conducting part is suitable for being in heat conducting connection with the side edge of the temperature equalizing plate.

Further, the phase change heat dissipation device is a heat pipe.

Furthermore, a phase change heat storage material layer is further arranged at the bottom of the mounting hole, and the phase change heat dissipation device is arranged on the upper portion of the phase change heat storage material layer.

Further, a ceramic interface layer is arranged on the top of the phase change heat dissipation device.

Furthermore, a second circuit is arranged between the first base material and the second base material, and a third circuit is arranged at the bottom of the second base material.

Further, the printed circuit board further comprises one or more third base materials, the third base materials are sequentially stacked to the bottom of the second base material, a plurality of fourth circuit layers are arranged on the third base materials, a plurality of second through holes are formed in the third base materials, heat conducting portions are arranged in the second through holes, and the heat conducting portions conduct heat to the outer side face of the bottommost third base material layer.

Furthermore, the printed circuit board further comprises a fourth base material, the fourth base material is clamped between the first base material and the second base material, the mounting hole penetrates through the fourth base material, and the fourth base material is provided with a fifth circuit.

Further, the heat conducting portion is a frustum-shaped laminated hole group and/or a cylindrical mechanical hole group.

Compared with the prior art, the invention has the advantages that: the invention provides a printed circuit board with an embedded phase-change heat dissipation device, which comprises a first base material, a second base material, a first circuit positioned on the top of the first base material, a bonding pad connected with the first circuit, the phase-change heat dissipation device and a heat conduction part. According to the invention, the first base material below the bonding pad is provided with the mounting hole and used for embedding the phase change heat dissipation device, the power device is welded on the bonding pad, when the power device generates high Joule heat at a high current instantly, the heat can be quickly guided, and the whole printed circuit board is utilized for assisting in heat dissipation, so that the temperature of the power device is kept stable. The phase-change heat dissipation device is creatively embedded in the first base material, so that the space can be saved compared with the prior art in which the phase-change heat dissipation device is arranged above the power element, and the heat dissipation structure is already included in the process of designing the circuit board. Because the phase change heat dissipation device is positioned in the first base material, the heat conduction part is adopted to transfer heat in the phase change heat dissipation device downwards, the temperature of the phase change heat dissipation device is guaranteed to be maintained in a certain range, and the technical effect of quick and stable heat dissipation is realized.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and together with the description serve to explain the principles of the invention.

FIG. 1 is a schematic view of a first embodiment of a thermal spreader embedded printed circuit board of the present invention;

FIG. 2 is a schematic view of a second embodiment of a thermal spreader embedded printed circuit board of the present invention;

FIG. 3 is a schematic view of a third embodiment of a thermal spreader embedded printed circuit board of the present invention;

fig. 4 is a schematic view of an embodiment of a printed circuit board with embedded heat pipes according to the present invention.

Wherein:

1. a power device; 2. a pad; 3. a first circuit; 4. a ceramic interfacial layer; 5. a temperature equalizing plate; 6. a phase change heat storage material layer; 7. a frustum-shaped stacked hole group; 71. a first frustum-shaped stacked hole group; 72. a second frustum-shaped stacked hole group; 8. a group of cylindrical stacked holes; 81. a first group of cylindrical stacked holes; 82. a second cylindrical stacked hole group; 9. a second circuit; 10. a third circuit; 11. a fourth circuit; 12. a first heat-dissipating copper foil; 13. a second heat-dissipating copper foil; 14. a condensing section; 15. an evaporation section; 16. a fifth circuit; 21. a first substrate; 22. a second substrate; 23. a third substrate; 24. a fourth base material; 51. a heat pipe.

Detailed Description

The present invention will be described in further detail with reference to the drawings and embodiments. It is to be understood that the specific embodiments described herein are for purposes of illustration only and are not to be construed as limitations of the invention. It should be noted that, for convenience of description, only the portions related to the present invention are shown in the drawings.

In addition, the embodiments of the present invention and the features of the embodiments may be combined with each other without conflict. The present invention will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.

Referring to fig. 1, the present invention provides a schematic diagram of a first embodiment of a printed circuit board with a built-in temperature-uniforming plate 5, which includes a first substrate 21, a second substrate 22, a first circuit 3 on top of the first substrate 21, a pad 2 connected to the first circuit 3, a temperature-uniforming plate 5 and a heat conducting portion.

The bonding pad 2 is used for welding the power device 1, and the bonding pad 2 is conducted with the first circuit 3, so that the power device 1 is connected in a circuit. The first base material 21 below the bonding pad 2 is provided with a mounting hole for embedding the temperature equalizing plate 5.

In a preferred embodiment, the mounting holes are opened from the bottom of the first base 21. Therefore, the upper surface of the first substrate 21 is not damaged, and the first circuit 3 can be directly etched on the upper surface of the first substrate 21. The second substrate 22 and the first substrate 21 are pressed together to form a space for accommodating the vapor chamber 5. Naturally, since the thinner wall surface of the top of the mounting hole and the first circuit 3 ensures that the temperature-uniforming plate 5 can quickly absorb heat from the power device 1, the ceramic interface layer 4 is provided on the temperature-uniforming plate 5 in order to prevent the temperature-uniforming plate 5 from contacting the pad 2 or the first circuit 3. The ceramic interface layer 4 serves as an insulator to prevent short-circuiting of the first circuit 3. In a preferred embodiment, the ceramic interface layer 4 is a nano ceramic interface layer, which increases the hardness, toughness, wear resistance, bonding strength, and corrosion resistance of the interface layer, and ensures good thermal conductivity.

In another preferred embodiment, the mounting holes are opened from the top of the first substrate 21. And after the temperature equalizing plate 5 is arranged in the mounting hole, the ceramic interface layer 4 covers the upper part of the temperature equalizing plate 5. Covering the etched first circuit 3 and mounting the power device 1 on top of the first circuit 3. The ceramic interface layer 4 serves as an insulator to prevent short-circuiting of the first circuit 3. In a preferred embodiment, the ceramic interface layer 4 is a nano ceramic interface layer, which increases the hardness, toughness, wear resistance, bonding strength, and corrosion resistance of the interface layer, and ensures good thermal conductivity.

Referring to fig. 1, a second circuit 9 is disposed between the second substrate 22 and the first substrate 21. The second circuit 9 is not in contact with the vapor chamber 5. The temperature equalization plate 5 is preferably a VC (vapor chambers) temperature equalization plate. The area of the VC temperature equalization plates 5 should be much larger than the area of the power device 1. Preferably, the area of the VC temperature equalization plate 5 is equal to or more than ten times the area of the power device 1.

Further, the temperature equalizing plate 5 is located right below the power device 1, the second substrate 22 is provided with a plurality of through holes, the through holes are provided with heat conducting portions, and heat of the temperature equalizing plate 5 is suitable for being transmitted to the bottom of the second substrate 22 along the heat conducting portions. The heat conducting part is suitable for being in heat conducting connection with the side edge of the VC temperature-uniforming plate 5. Thus, the evaporation portion 15 is formed at a portion of the VC temperature-uniforming plate 5 adjacent to the power device 1 (the middle portion of the temperature-uniforming plate 5). The vapor chamber 5 is a vacuum chamber with a fine structure on the inner wall, and is usually made of copper. When heat is conducted from the power device 1 to the evaporation part 15, the cooling liquid in the cavity starts to generate a gasification phenomenon of the cooling liquid after being heated in a low-vacuum environment, and at the moment, the cooling liquid absorbs heat energy and expands rapidly in volume to form higher air pressure, so that the gas moves to the other side surface of the temperature equalizing plate 5 and is rapidly dispersed. On the side of the vapor chamber 5, since the heat of the vapor chamber 5 is conducted to the outside by the heat conduction portion, the temperature of the vapor chamber 5 is low, and thus the condensation portion 14 is formed. The gas phase working medium generates condensation in the condensation part 14, the heat accumulated during evaporation is released by the condensation, and the condensed cooling liquid returns to the evaporation heat source by the capillary tube of the microstructure, and the operation is repeated in the cavity.

In the preferred technical scheme, the bottom of the mounting hole is further provided with a phase change heat storage material layer 6, and the temperature equalizing plate 5 is arranged on the upper portion of the phase change heat storage material layer 6. The heat conducting part is connected with the phase change heat storage material layer 6. The phase change conversion process of the phase change heat storage material layer 6 is rapid, the absorbed heat is related to the latent heat of the material, and the larger the latent heat of phase change is, the larger the heat which can be absorbed is. The phase-change heat storage material layer 6 can rapidly absorb high joule heat generated on the line due to high current by phase-change latent heat. Of course, the phase change heat storage material layer 6 may be disposed on a side of the temperature equalizing plate 5 and connected thereto using a heat conducting portion.

A second circuit 9 is disposed between the first substrate 21 and the second substrate 22, and a third circuit 10 is disposed on the bottom of the second substrate 22. Therefore, a multilayer circuit is formed, and the multilayer circuit board can be internally wired, thereby being beneficial to high integration of the circuit board.

In a preferred embodiment, the heat conducting part further comprises a plurality of third substrates 23, the third substrates 23 are sequentially stacked on the bottom of the second substrate 22, a plurality of fourth circuits 11 are arranged on the third substrates 23, the through holes penetrate through the third substrates 23, and the heat conducting part guides heat to the outer side face of the bottommost third substrate 23. The number of the third base materials 23 is more than or equal to 1, and the number of the fourth circuits 11 is more than or equal to 1. The first circuit 3, the second circuit 9, the third circuit 10, and the fourth circuit 11 can be electrically connected to each other through the via hole.

The heat conduction portion is required to guide heat to the outside of the base material. Therefore, the through-hole needs to penetrate the third base material 23. The heat conducting part is a frustum-shaped overlapped hole group 7 and/or a cylindrical mechanical hole group 8. Referring to fig. 1, there is shown an embodiment having both a frustum-shaped stacked hole group 7 and a cylindrical mechanical hole group 8. Copper columns are arranged in the frustum-shaped stacked hole group 7 and the cylindrical mechanical hole group 8, a radiating copper foil 12 is arranged on the third base material 23 at the bottommost part of the frustum-shaped stacked hole group 7, and a circuit part 13 is arranged on the third base material 23 at the bottommost part of the cylindrical mechanical hole group 8. The radiating copper foil can increase the radiating area, so that the heat guided by the heat conducting part is easier to exchange. In a preferred embodiment, the group of cylindrical mechanical holes can be both conductive traces and a heat sink path. Because the heat dissipation and the electric conduction functions are integrated, the miniaturization of the PCB is facilitated.

Further, heat dissipation copper foils are also arranged between the second base material 22 and the third base material 23 and between the plurality of third base materials 23, and the heat dissipation copper foils at the positions can be used for uniformly connecting the stacked holes in the stacked hole group into a whole and then transmitting the whole to the side face of the next base material, so that uniform and efficient heat dissipation is guaranteed.

Referring to fig. 2, a schematic diagram of a second embodiment of a printed circuit board with embedded vapor chamber 5 is provided. In this embodiment, the design of the first substrate 21, the second substrate 22, the third substrate 23, the stacked hole group, the temperature equalization plate 5, and the like is the same as that of the first embodiment, except that the second embodiment adds the fourth substrate 24 between the first substrate 21 and the second substrate 22, so that a plurality of fourth substrates 24 are sandwiched between the first substrate 21 and the second substrate 22. The mounting hole penetrates the fourth base material 24, and the fourth base material 24 is provided with the fifth circuit 16. Therefore, the accommodating space of the temperature equalizing plate 5 is enlarged, more circuit layers can be distributed, and the integration of circuits is facilitated.

Referring to fig. 3, a schematic diagram of a third embodiment of a printed circuit board with embedded vapor chamber 5 is provided. In this embodiment, the design of the first substrate 21, the second substrate 22, the third substrate 23, the vapor chamber 5, and the like is the same as the second example. However, in the third embodiment, since the substrates of the plurality of layers are stacked, the groups of the stacked holes of the upper and lower substrates do not exactly correspond to each other. Specifically, the frustum-shaped stacked hole group 7 is divided into a first frustum-shaped stacked hole group 71 and a second frustum-shaped stacked hole group 72; the group of cylindrical mechanical holes 8 is divided into a first group of cylindrical mechanical holes 81 and a second group of cylindrical mechanical holes 82. The first frustum-shaped laminated hole group 71 and the first cylindrical mechanical hole group 81 are located in the second substrate 22, and the second frustum-shaped laminated hole group 72 and the second cylindrical mechanical hole group 82 are located in the third substrate 23, so that heat of the second substrate 22 can be guided to the third substrate 23 along the heat dissipation copper foil, flexible manufacturing of the circuit board is achieved, and no rigidity is caused due to the existence of heat dissipation parts.

It should be noted that the first substrate 21, the second substrate 22, the third substrate 23, and the fourth substrate 24 mentioned in the present invention are prepregs, and the first substrate 21, the second substrate 22, the third substrate 23, and the fourth substrate 24 include at least one insulating core layer.

Referring to fig. 4, the present invention provides a schematic diagram of an embodiment of a printed circuit board with a heat pipe 51 embedded therein, which includes a first substrate 21, a second substrate 22, a third substrate 23, a first circuit 3 on top of the first substrate 21, the heat pipe 51, and a heat conducting portion. The first circuit 3 is soldered with the power device 1 through a pad so that the power device 1 is connected in a circuit. The first substrate 21 is provided with a mounting hole for embedding the heat pipe 51.

In a preferred embodiment, the mounting holes are opened from the bottom of the first base 21. Therefore, the upper surface of the first substrate 21 is not damaged, and the first circuit 3 can be directly etched on the upper surface of the first substrate 21. The second substrate 22 is pressed with the first substrate 21 to form a space for accommodating the heat pipe 51. Naturally, since the thin wall surface of the top of the mounting hole and the first circuit 3 ensures that the heat pipe 51 can quickly absorb heat from the power device 1, the ceramic boundary layer 4 is provided on the heat pipe 51 in order to avoid contact between the heat pipe 51 and the first circuit 3. The ceramic interface layer 4 has insulating and heat conducting functions and prevents the first circuit 3 from being short-circuited. In a preferred embodiment, the ceramic interface layer 4 is a nano ceramic interface layer, which increases the hardness, toughness, wear resistance, bonding strength, and corrosion resistance of the interface layer, and ensures good thermal conductivity.

The heat conduction portion is required to guide heat to the outside of the base material. Therefore, the through-hole needs to penetrate through the second substrate 22 and the third substrate 23. The heat conducting part is a frustum-shaped overlapped hole group 7 and/or a cylindrical mechanical hole group 8. Referring to fig. 4, an embodiment having both a frustum-shaped stacked hole group 7 and a cylindrical mechanical hole group 8 is shown. Copper columns are arranged in the frustum-shaped laminated hole group 7 and the cylindrical mechanical hole group 8 and used for heat dissipation or heat dissipation and electric conduction at the same time, and which function is related to circuit design is specifically realized.

In the description herein, reference to the description of the terms "one embodiment/mode," "some embodiments/modes," "example," "specific example," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment/mode or example is included in at least one embodiment/mode or example of the application. In this specification, the schematic representations of the terms used above are not necessarily intended to be the same embodiment/mode or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments/modes or examples. Furthermore, the various embodiments/aspects or examples and features of the various embodiments/aspects or examples described in this specification can be combined and combined by one skilled in the art without conflicting therewith.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature. In the description of the present application, "plurality" means at least two, e.g., two, three, etc., unless explicitly specified otherwise.

It will be understood by those skilled in the art that the foregoing embodiments are merely for clarity of description and are not intended to limit the scope of the invention. Other variations or modifications will occur to those skilled in the art based on the foregoing disclosure and are within the scope of the invention.

Claims

1. The utility model provides an embedded phase transition heat dissipation device's printed circuit board which characterized in that: the heat-conducting module comprises a first substrate, a second substrate, a first circuit positioned on the top of the first substrate, a bonding pad connected with the first circuit, a temperature-equalizing plate and a heat-conducting part;

the welding pad is used for welding a power device, a first base material below the welding pad is provided with a mounting hole for embedding the temperature-equalizing plate, and the temperature-equalizing plate is mounted in the mounting hole; the second substrate is provided with a plurality of first through holes, the first through holes are provided with heat conducting parts, the heat of the temperature equalizing plate is suitable for being transferred to the bottom of the second substrate along the heat conducting parts, and the heat conducting parts are in heat conducting connection with the side edges of the temperature equalizing plate; the bottom of the mounting hole is also provided with a phase change heat storage material layer, the temperature equalizing plate is arranged on the upper part of the phase change heat storage material layer, and the bottom of the temperature equalizing plate covers the phase change heat storage material layer; the area of the temperature equalizing plate is larger than or equal to ten times of the area of the power device.

2. The printed circuit board of claim 1, wherein: and a ceramic interface layer is arranged at the top of the temperature equalizing plate.

3. The printed circuit board of claim 1, wherein: a second circuit is arranged between the first base material and the second base material, and a third circuit is arranged at the bottom of the second base material.

4. The printed circuit board of claim 1, wherein: still include one or more third substrate, the third substrate superposes to second substrate bottom in proper order, is provided with a plurality of fourth circuit layers on the third substrate, the third substrate is equipped with a plurality of second through-holes, the second through-hole sets up the heat conduction portion, the heat conduction portion leads the heat to the third substrate lateral surface of bottommost.

5. The printed circuit board of claim 1, wherein: the mounting hole penetrates through the fourth base material, and the fourth base material is provided with a fifth circuit.

6. The printed circuit board of claim 1, wherein: the heat conducting part is a frustum-shaped stacked hole group and/or a cylindrical mechanical hole group.