CN111354692A - Power cooling device - Google Patents

Abstract

The present application relates to the field of semiconductors, and discloses a power cooling device. In the present application, the power cooling device includes a first circuit board, a second circuit board, a first heat-conducting plate and a second heat-conducting plate; wherein the first circuit board and the second circuit board are electrically connected through copper posts, and the copper posts are arranged on the first circuit board. Between the board and the second circuit board, a space capable of accommodating at least one chip is formed between the first circuit board and the second circuit board; the second heat conducting board is arranged on the side of the second circuit board away from the first circuit board, and the first A heat-conducting plate is arranged on the side of the first circuit board away from the second circuit board; the second heat-conducting plate is fixedly connected with the first heat-conducting plate, so that the heat of the second heat-conducting plate can be transferred to the first heat-conducting plate.

Description

Power cooling device

technical field

The present application relates to the field of semiconductors, and in particular, to a power cooling device.

Background technique

Power electronic technology is an important basic technology of my country's national economy and the core technology of modern science, industry and national defense. As the foundation and core of power electronic technology, power devices have been widely used in aerospace, photovoltaic power generation, energy development, industrial frequency conversion, transportation and other fields. The power module is a device packaging form commonly used in high-power applications, and it is one of the driving forces for the installation and integration of power electronic systems. As a power cooling device, the power module is responsible for the integration and heat dissipation of the power die. Its role is irreplaceable.

The existing power cooling device, the so-called power module, has two cooling forms. One is the traditional single-sided cooling power cooling device (as shown in Figure 1), which only installs a heat sink on the lower surface of the chip. The heat dissipation efficiency is very low. The other is a new type of double-sided cooling power heat dissipation device (as shown in Figure 2), which installs heat sinks on the upper and lower surfaces of the chip, and has high heat dissipation efficiency. Some of the most cooling systems are not compatible.

SUMMARY OF THE INVENTION

In order to solve the above-mentioned problems, the embodiments of the present application provide a power heat dissipation device. Although the structure is the same as that of the traditional single-sided cooling power heat dissipation device, its heat dissipation effect is close to that of the new double-sided cooling power heat dissipation device, and is compatible with various types of power dissipation devices. cooling system.

In a first aspect, an embodiment of the present application provides a power heat dissipation device, the power heat dissipation device includes a first circuit board, a second circuit board, a first heat-conducting plate, and a second heat-conducting plate; wherein

The first circuit board and the second circuit board are electrically connected through copper pillars, and the copper pillars are arranged between the first circuit board and the second circuit board, so that the first circuit board is connected to the second circuit board. A space capable of accommodating at least one chip is formed between the second circuit boards;

The second heat-conducting plate is arranged on the side of the second circuit board away from the first circuit board, and the first heat-conducting plate is arranged at the side of the first circuit board away from the second circuit board;

The second heat-conducting plate is fixedly connected to the first heat-conducting plate, so that the heat of the second heat-conducting plate can be transferred to the first heat-conducting plate.

In a possible implementation of the above-mentioned first aspect, a buffer material is filled between the second circuit board and the second heat conducting plate.

In a possible implementation of the above-mentioned first aspect, the buffer material includes thermally conductive silica gel or metal foam material.

In a possible implementation of the above-mentioned first aspect, the circuit board includes a copper-clad ceramic substrate.

In a possible implementation of the above-mentioned first aspect, the copper-clad ceramic substrate includes a ceramic layer and a copper foil layer covering the upper and lower surfaces of the ceramic layer, wherein a circuit is etched on the surface of the copper foil layer in contact with the chip, The circuit is used to transmit electrical signals of the chip.

In a possible implementation of the above-mentioned first aspect, the thermally conductive plate includes any one of the following materials: copper or aluminum.

In a possible implementation of the above-mentioned first aspect, one side of the power cooling device is connected to an external thermal conductor, and the external thermal conductor includes an air-cooled radiator, a liquid-cooled radiator, or natural cooling.

In a possible implementation of the above-mentioned first aspect, a chip is welded between the first circuit board and the second circuit board.

In a possible implementation of the above-mentioned first aspect, a plurality of chips are soldered between the first circuit board and the second circuit board.

In a possible implementation of the above-mentioned first aspect, the power cooling device includes a plurality of second circuit boards, one side of each chip in the plurality of chips is respectively connected to a second circuit board, and the plurality of chips are respectively connected to a second circuit board. The other side of each chip is soldered on the same first circuit board.

Description of drawings

FIG. 1 shows a schematic structural diagram of a single-sided cooling power heat dissipation device produced by a traditional process;

FIG. 2 shows a schematic structural diagram of a double-sided cooling power cooling device produced by a novel process;

FIG. 3 shows a schematic structural diagram of a power cooling device according to some embodiments of the present application;

4 shows a schematic structural diagram of a DBC substrate according to some embodiments of the present application;

Fig. 5 shows a manufacturing flow chart of a power cooling device according to some embodiments of the present application;

FIG. 6 is a schematic structural diagram of another power cooling device according to some embodiments of the present application.

specific embodiment

Illustrative embodiments of the present application include, but are not limited to, power heat sinks.

The embodiments of the present application will be described in further detail below with reference to the accompanying drawings.

FIG. 1 shows a schematic structural diagram of a single-sided cooling power heat dissipation device produced by a traditional process. The single-sided cooling power heat dissipation device 100 shown in FIG. 1 includes a circuit board 103 welded on the back of the chip 101 , wherein the circuit board 103 and the chip 101 are electrically connected by bonding wires 102 , and the circuit board 103 is welded on the heat-conducting plate 104 . A heat sink 105 is installed under the heat conducting plate 104 . Because the heat generated by the chip 101 can only be conducted to the heat sink 105 through the lower circuit board 103 and the heat conducting plate 104, the heat dissipation efficiency of the single-sided cooling power heat dissipation device 100 is very low. It should be noted that the bonding wire 102 electrically connects the chip 102 and the circuit board 103 through wire bonding (WB, Wire Bonding). It is tightly welded with the pad of the circuit board to realize the electrical interconnection between the chip and the circuit board and the information exchange between the chips.

FIG. 2 shows a schematic structural diagram of a double-sided cooling power cooling device produced by a novel process. The double-sided cooling power heat dissipation device 200 shown in FIG. 2 includes a circuit board 202 welded on the back of the chip 201 and a circuit board 203 welded on the front of the chip 201 , and the circuit board 202 and the circuit board 203 are welded on the heat-conducting plate 204 and the heat-conducting plate 205 respectively. On the top, the heat sink 206 is installed above the heat conduction plate 205 , and the heat sink 207 is installed under the heat conduction plate 204 . As can be seen from the figure, since radiators are installed on the upper and lower surfaces of the double-sided cooling power dissipation device 200, the heat dissipation efficiency of the double-sided cooling device 200 is high. Some of the most cooling systems are not compatible.

FIG. 3 shows a schematic structural diagram of a power cooling device 300 according to some embodiments of the present application. The power cooling device 300 shown in FIG. 3 includes a first circuit board 303 and a second circuit board 304 soldered on the back and front of the chip 301 respectively, wherein the first circuit board 303 and the second circuit board 304 are electrically connected through the copper pillars 302 For connection, the first circuit board 303 is welded on the first heat-conducting plate 305, the external heat-conducting body 308 is installed under the first heat-conducting plate 305, the second heat-conducting plate 307 is installed above the second circuit board 304, and the second circuit board 304 and A buffer material 306 is filled between the second heat-conducting plates 307 , and both sides of the second heat-conducting plate 307 and the first heat-conducting plate 305 are fixedly connected. It can be understood that the buffer material 306 includes, but is not limited to, metal foam material or thermally conductive silica gel, which is used to reduce the stress on the chip 301 when the second thermally conductive plate 307 thermally expands. In other embodiments of the present application, the power cooling device 300 The buffer material 306 may not be included, which is not limited herein. In the figure, the arrows in the second heat conducting plate 307 indicate the direction of heat conduction.

It should be noted that the circuit boards in this application include but are not limited to copper clad ceramic substrates (DBC, Direct Bond Copper), printed circuit boards (PCB, Printed Circuit Board), etc., which are not limited here.

In some embodiments of the present application, the circuit board adopts a DBC substrate, which has excellent thermal cycleability, stable shape, good rigidity and high thermal conductivity. Taking the first circuit board 303 in FIG. 3 as an example, FIG. 4 shows a schematic structural diagram of the first circuit board 303 being a DBC substrate. The DBC substrate shown in FIG. 4 includes a ceramic layer 401, an upper copper foil layer 402 covering the upper surface of the ceramic layer, and a lower surface covering the lower surface of the ceramic layer. The copper foil layer 403, wherein the upper copper foil layer 402 is etched with circuits for transmitting the electrical signals of the chip 301, and the lower copper foil layer 403 has a complete surface and does not need to be etched.

The following is a detailed description of the preparation process of the power cooling device 300 according to the embodiment of the present application. (a) to (d) in FIG. 5 show the preparation flow chart of the power cooling device 300, as shown in FIG. 5 , including:

(a) Coat the solder paste on the position to be soldered on the front side of the first circuit board 303 through a screen printing process, and then reflow solder the chip 301 and the copper pillar 302 on the first circuit board 303, in order to ensure that the copper pillar 302 and the chip The positions of 301 are accurate and will not shift during reflow soldering, and their positions can be fixed by molds, and then reflow soldering to form a stable mechanical and electrical structure. Reflow soldering refers to the use of solder paste (a mixture of solder and flux) to connect one or more electronic components to the contact pads, and then controlled heating to melt the solder to achieve permanent bonding. Different heating methods such as infrared heating lamps or heat guns are used for welding.

(b) Coating the solder paste on the lower surface of the second circuit board 304 to be soldered by a screen printing process, and then reflow soldering the chip 301 and the copper posts 302 on the lower surface of the second circuit board 304 to be soldered, so that The second circuit board 304 is fixedly connected to the chip 301 and the copper pillars 302 . It can be understood that the copper posts are used to realize the electrical connection between the first circuit board 303 and the second circuit board 304, so as to transmit the electrical signals of the chip 301, and the copper posts have shorter circuit paths than the bonding wires , the resistance and parasitic inductance are reduced, so that the power device has better electrical performance. It should be noted that screen printing refers to using a screen as a plate base, and using a photosensitive plate-making method to make a screen printing plate with graphics and text.

(c) reflow soldering the power cooling device in FIG. (b) on the first heat-conducting plate 305. The first heat-conducting plate 305 may have its own heat sink, or an external heat-conducting body (not shown in the figure) may be installed at the bottom, It can be understood that the external heat conductor may be an air-cooled radiator, a liquid-cooled radiator, or natural cooling (eg, air), which is not limited herein. The structure of the power cooling device in the figure is the same as that of the traditional single-sided cooling power cooling device 100. Therefore, the power cooling device of the embodiment of the present application is not different from the traditional single-sided cooling device in appearance design, and can directly replace the traditional single-sided cooling device. Surface cooling of the power cooling device without changing other structures of the entire cooling system.

(d) Install the second thermal conductive plate 307 above the second circuit board 304 and fill the buffer material 306 therebetween. The buffer material 306 includes but is not limited to metal foam material, thermal conductive silica gel, etc., which is not limited here. Both sides of the second heat-conducting plate 307 are fixedly connected to the first heat-conducting plate 305, so that the heat generated by the chip 301 can be transferred to the second heat-conducting plate 307 through the second circuit board 304 and the buffer material 306, and then the second heat-conducting plate 307 passes through the two heat-conducting plates 307. The side heat-conducting plates transfer heat to the first heat-conducting plate 305 (the arrows in the figure indicate heat transfer paths), and such additional heat transfer paths improve the heat dissipation performance of the power heat dissipation device 300 .

According to some embodiments of the present application, FIG. 6 shows another power cooling device 600 . The power cooling device 600 in FIG. 6 includes two chips 301 , and a circuit board 304 is welded to the upper surfaces of the two chips 301 . The lower surfaces of the two chips 301 are soldered on the same first circuit board 303 , and the two chips 301 are interconnected through the first circuit board 303 . It can be understood that although the power heat dissipation device shown in FIG. 6 can dissipate heat for two chips, in fact, the power heat dissipation device can also dissipate heat for one or more than two chips, which is not limited here.

It should be noted that the area of the second heat-conducting plate 307 is not necessarily the same as the area of the first heat-conducting plate 305. In order to avoid structures such as pins, the area of the second heat-conducting plate 307 may be reduced or a plurality of smaller areas may be used. The second heat-conducting plate 307 can be connected to the first heat-conducting plate 305 at other positions, such as the middle position, except that heat can be transferred on both sides of the same second heat-conducting plate 307 , which is not limited here.

It should be noted that, the chip 301 can also be connected to the first circuit board 303 by other means, such as copper tape bonding, and then a buffer material is filled between the copper tape and the second thermal conductive plate 307, and the gap portion of the power cooling device 300 is also The potting compound can be filled to better protect the mechanical structure of the power cooling device, so as to improve the dielectric properties and thermal conductivity of the entire power cooling device.

Therefore, although the power cooling device provided in the embodiment of the present application has the same structure as the traditional single-sided cooling power cooling device, its cooling effect is close to that of the new double-sided cooling power cooling device, and is compatible with various cooling systems.

In the drawings, some structural or method features may be shown in specific arrangements and/or sequences. It should be understood, however, that such specific arrangements and/or orderings may not be required. Rather, in some embodiments, the features may be arranged in a manner and/or order different from that shown in the illustrative figures. Additionally, the inclusion of structural or method features in a particular figure is not meant to imply that such features are required in all embodiments, and in some embodiments such features may not be included or may be combined with other features.

It should be noted that each unit/device mentioned in each device embodiment of this application is a logical unit/device. Physically, a logical unit/device may be a physical unit/device or a physical unit/device. A part of the device can also be implemented by a combination of multiple physical units/devices. The physical implementation of these logical units/devices is not the most important, and the combination of functions implemented by these logical units/devices is the solution to the problem of this application. The crux of the technical question raised. In addition, in order to highlight the innovative part of the present application, the above-mentioned device embodiments of the present application do not introduce units/devices that are not closely related to solving the technical problems raised in the present application, which does not mean that the above-mentioned device embodiments do not exist. other units/devices.

It should be noted that, in the examples and specification of this patent, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that Any such actual relationship or sequence exists between these entities or operations. Moreover, the terms "comprising", "comprising" or any other variation thereof are intended to encompass a non-exclusive inclusion such that a process, method, article or device that includes a list of elements includes not only those elements, but also includes not explicitly listed or other elements inherent to such a process, method, article or apparatus. Without further limitation, an element qualified by the phrase "comprising a" does not preclude the presence of additional identical elements in a process, method, article, or device that includes the element.

Although the present application has been illustrated and described with reference to certain preferred embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and detail may be made therein without departing from the present disclosure The spirit and scope of the application.

Claims (10)

1. A power cooling device, characterized in that the power cooling device comprises a first circuit board, a second circuit board, a first heat-conducting plate and a second heat-conducting plate; wherein The first circuit board and the second circuit board are electrically connected through copper pillars, and the copper pillars are arranged between the first circuit board and the second circuit board, so that the first circuit board is connected to the second circuit board. A space capable of accommodating at least one chip is formed between the second circuit boards; The second heat-conducting plate is arranged on the side of the second circuit board away from the first circuit board, and the first heat-conducting plate is arranged at the side of the first circuit board away from the second circuit board; The second heat-conducting plate is fixedly connected to the first heat-conducting plate, so that the heat of the second heat-conducting plate can be transferred to the first heat-conducting plate. 2 . The power cooling device according to claim 1 , wherein a buffer material is filled between the second circuit board and the second heat conducting plate. 3 . 3 . The power cooling device according to claim 2 , wherein the buffer material comprises thermally conductive silica gel or metal foam material. 4 . 4. The power cooling device according to claim 1, wherein the circuit board comprises a copper-clad ceramic substrate. 5. The power cooling device according to claim 4, wherein the copper-clad ceramic substrate comprises a ceramic layer and a copper foil layer covering the upper and lower surfaces of the ceramic layer, wherein the surface of the copper foil layer in contact with the chip Circuits are etched for transmitting electrical signals of the chip. 6 . The power cooling device according to claim 1 , wherein the heat conducting plate comprises any one of the following materials: copper or aluminum. 7 . 7 . The power cooling device according to claim 1 , wherein one side of the power cooling device is connected to an external thermal conductor, and the external thermal conductor comprises an air-cooled radiator, a liquid-cooled radiator or natural cooling. 8 . 8 . The power cooling device according to claim 1 , wherein a chip is welded between the first circuit board and the second circuit board. 9 . 9 . The power cooling device according to claim 1 , wherein a plurality of chips are welded between the first circuit board and the second circuit board. 10 . 10 . The power cooling device according to claim 9 , wherein the power cooling device comprises a plurality of second circuit boards, and one side of each chip in the plurality of chips is respectively connected with a second circuit board. 11 . connected, and the other sides of the plurality of chips are soldered on the same first circuit board.

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