A mold for packaging power module, packaging method, power module assembly, and power device

Abstract

This application provides a mold for packaging a power module, a packaging method, a power module assembly, and a power device. The mold comprises a top mold, a bottom mold, and two water channel molds. Using the mold provided herein, this packaging method can form internal cooling channels within a seal, enabling the power module to achieve dual-sided heat dissipation using a single heat sink.

Description

Technical Field

[0001] The present application relates to the technical field of power module heat dissipation, and in particular to a mold for packaging a power module, a packaging method, a power module assembly, and a power device. Background Art

[0002] Semiconductor power modules such as IGBTs and SiC have a wide range of applications, including inverters for electric vehicles. Because their high power generates significant heat, heat dissipation is a crucial performance characteristic of these modules. Excellent heat dissipation ensures stable and reliable operation.

[0003] Currently, semiconductor power modules primarily rely on heat sinks for heat dissipation. Typically, single-sided cooling is preferred over double-sided cooling. This is because single-sided water cooling requires only one heat sink, simplifies mechanical installation, and requires minimal manufacturing process. Double-sided cooling, on the other hand, requires two heat sinks, which is complex and requires high manufacturing process requirements. Furthermore, double-sided cooling modules with pinfins often require custom heat sinks of the appropriate size, resulting in high manufacturing costs. Summary of the Invention

[0004] In order to solve the above technical problems, the present application provides a mold for packaging a power module, a packaging method, a power module assembly, and a power device. The packaging method uses the mold to form an internal cooling channel in the seal, so that the power module can achieve double-sided heat dissipation through only one heat sink.

[0005] In a first aspect, the present application provides a mold for packaging a power module, wherein the power module includes a semiconductor chip located in the middle, and heat dissipation substrates located on top and bottom of the semiconductor chip, wherein heat dissipation fins are formed on the heat dissipation substrates. The mold includes:

[0006] A top mold, wherein the top mold is a hollow shell structure with an open bottom, and a potting material injection port and two water channel insertion ports are formed on the top of the top mold;

[0007] A bottom mold, wherein the bottom mold is a hollow shell structure with openings at the top and bottom. The opening at the top of the bottom mold corresponds to the opening at the bottom of the top mold. The opening at the bottom of the bottom mold corresponds to the size of the heat dissipation fins at the bottom of the power module. Two water channel insertion openings are correspondingly formed at the bottom of the bottom mold. The bottom mold and the bottom mold together form an internal cavity for placing the power module.

[0008] Two water channel molds can be inserted into the mold through the water channel insertion port of the top mold or the bottom mold.

[0009] According to the first aspect, using the mold of the present application to encapsulate the power module can form an internal cooling channel in the seal, so that the power module can achieve double-sided heat dissipation through only one heat sink, thereby simplifying the structure and process requirements and reducing costs.

[0010] According to the first aspect, or any implementation of the first aspect above, terminal extension slots are formed on side surfaces of the top mold and the bottom mold adjacent to the water channel insertion opening. The terminal extension slots of the top mold and the terminal extension slots of the bottom mold together form an opening through which the terminals of the power module extend to the exterior of the mold. In this way, when the power module is placed within the mold, the terminals on the power module extend outside the mold, thereby preventing potting compound from forming on the terminals during the encapsulation process.

[0011] In a second aspect, a packaging method for a power module is provided, wherein the power module includes a semiconductor chip located in the middle, and heat dissipation substrates located on top and bottom of the semiconductor chip, wherein heat dissipation fins are formed on the heat dissipation substrates, and the packaging method includes:

[0012] Cover the heat dissipation fins of the heat dissipation substrate on the top of the power module with a removable formable material and shape it;

[0013] Placing the power module into the mold described in the first aspect, and adjusting the position of the water channel mold so that the water channel mold is aligned with the removable formable material formed on the top;

[0014] Using the mold to complete the packaging through a potting process;

[0015] The mold is removed, and a high-pressure liquid flow is introduced into the cooling channel in the power module to flush out the removable moldable material.

[0016] According to the second aspect, the packaging method of the present application can form an internal cooling channel in the seal using the mold of the present application, so that the power module can achieve double-sided heat dissipation through only one heat sink.

[0017] According to the second aspect, or any implementation of the second aspect above, the height of the shaped sand is higher than the height of the heat dissipation fins of the heat dissipation substrate on the top of the power module, so as to facilitate the formation of a cooling channel in the top area during the packaging process.

[0018] In a third aspect, the present application provides a power module assembly, comprising: a power module and a heat sink packaged using the packaging method described in the second aspect, wherein the power module comprises:

[0019] semiconductor chips;

[0020] A packaging substrate, wherein one packaging substrate is welded on the top and bottom of the semiconductor chip respectively;

[0021] a heat dissipation substrate, formed on a side of the packaging substrate away from the semiconductor chip, with heat dissipation fins formed on the heat dissipation substrate;

[0022] a sealing member, the sealing member wrapping the semiconductor chip, the packaging substrate, and the heat dissipation substrate excluding the heat dissipation fins, wherein the sealing member has cooling channels formed therein that communicate with the left and right sides and the top of the power module;

[0023] The power module is mounted on the radiator, and a heat dissipation substrate at the bottom of the power module and the radiator form a bottom cooling channel.

[0024] According to the power module assembly of the third aspect, double-sided heat dissipation can be achieved using only one heat sink, which has a simple structure and low cost.

[0025] According to the third aspect, or any implementation of the third aspect above, at least two power modules are mounted on the heat sink. This allows for installation of an appropriate number of power modules as needed, and since the heat sink is shared, the structure is simplified, process requirements are reduced, and thus costs are reduced.

[0026] In a fourth aspect, the present application provides a power device, comprising the power module assembly described in aspect 3. The power device is, for example, an inverter or other device.

[0027] According to the fourth aspect, the power module assembly according to the third aspect of the present application is adopted, so the cost is lower. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1A This is a schematic diagram of the structure of a single-sided heat dissipation power module component:

[0029] Figure 1B yes Figure 1A a schematic cross-sectional view of the power module assembly shown;

[0030] Figure 2A This is a schematic diagram of the structure of a current double-sided heat dissipation power module assembly;

[0031] Figure 2B yes Figure 2A Schematic diagram of the radiator;

[0032] Figure 3 is a cross-sectional schematic diagram of a power module assembly provided in an embodiment of the present application;

[0033] Figure 4 1 is a schematic structural diagram of a mold for packaging a power module provided in an embodiment of the present application;

[0034] Figure 5 1 is a schematic structural diagram of a mold for packaging a power module provided in an embodiment of the present application from another perspective;

[0035] Figure 6 1 is a schematic structural diagram of a mold for packaging a power module provided in an embodiment of the present application, wherein a water channel mold is inserted into a bottom mold;

[0036] Figure 7 is a schematic flow chart of the packaging method provided in an embodiment of the present application;

[0037] Figure 8 This is a schematic diagram of the sand after shaping;

[0038] Figure 9 This is a schematic diagram of the structure after the power module is placed in the mold;

[0039] Figure 10 This is a structural diagram from another perspective after the power module is placed in the mold;

[0040] Figure 11 This is a schematic cross-sectional view of the power module after it is placed in the mold. DETAILED DESCRIPTION

[0041] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0042] The term "and / or" in this article is merely a description of the association relationship between associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone.

[0043] In the description and claims of the embodiments of this application, the terms "first" and "second" are used to distinguish different objects, rather than to describe a specific order of objects. For example, the terms "first target object" and "second target object" are used to distinguish different objects, rather than to describe a specific order of objects.

[0044] In the embodiments of this application, words such as "exemplary" or "for example" are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "exemplary" or "for example" in the embodiments of this application should not be interpreted as being preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0045] In the description of the embodiments of this application, unless otherwise specified, "multiple" means two or more. For example, "multiple processing units" means two or more processing units; "multiple systems" means two or more systems.

[0046] Figure 1A This is a structural diagram of a single-sided heat dissipation power module. Figure 1B yes Figure 1A Schematic cross-sectional view of the power module assembly shown.

[0047] like Figure 1A and Figure 1B As shown, the power module assembly of this example includes a power module 100 and a heat sink 200. The power module 100 is, for example, an inverter or other power device composed of an IGBT module or a SiC module, and exemplarily has three power terminals 1, 2, and 3 and a plurality of signal terminals 4, wherein two power terminals are located on the same side, for example, the positive terminal (DC+) and the negative terminal (DC-) are located on the same side, and the other power terminal is located on the opposite side, for example, the alternating current (AC) terminal is located on the opposite side. Exemplarily, the signal terminal 4 and the power terminal 3 are located on the same side for connecting to an external control circuit. The number of signal terminals 4 is, for example, 6, for connecting, for example, gates and sources on different branches. A radiator 200 is installed at the bottom of the power module 100 (i.e., the side facing the radiator 200) (i.e., the power module 100 is installed / inserted on the radiator 200, and multiple power modules 100 share the same radiator). The radiator 200 has a water inlet 201 and a water outlet 202. The coolant enters from the water inlet 201, circulates inside the radiator 200, exchanges heat with the power module 100, and then flows out from the water outlet 202. A heat dissipation substrate can be installed at the bottom of the power module 100, and heat dissipation fins 16 (pinfins) can be formed on the substrate to improve the heat exchange efficiency with the radiator 200. For example, a slot can be formed on the radiator 200, and the power module 100 and the radiator 200 are connected by inserting the heat dissipation substrate into the radiator 200. For Figure 1A and Figure 1B The heat dissipation structure of the power module shown is simple in structure and has low process requirements, but can only achieve single-sided heat dissipation, and the heat dissipation capacity is low for high-power modules.

[0048] Figure 2A This is a schematic diagram of the structure of a current double-sided heat dissipation power module assembly; Figure 2B yes Figure 2A Schematic diagram of the radiator structure.

[0049] like Figure 2AAs shown, the power module assembly of this example includes a power module 100 and a heat sink 300 arranged in a stacked manner. The power module 100 is, for example, an IGBT module or a SiC module, which has three power terminals 1, 2, 3 and a plurality of signal terminals 4, wherein two power terminals are located on the same side, for example, the positive terminal (DC+) and the negative terminal (DC-) are located on the same side, and the other power terminal is located on the opposite side, for example, the alternating current (AC) terminal is located on the opposite side. Exemplarily, the signal terminal 4 and the power terminal 3 are located on the same side for connecting to an external control circuit. The number of signal terminals 4 is, for example, 6, for connecting, for example, gates and sources on different branches. In Figure 2A In the example shown, multiple power modules 100 and heat sinks 300 are stacked and spaced apart from each other, with each power module 100 inserted or embedded between two heat sinks 300. The top and bottom of the power module 100 are connected to the heat sink 300, thereby achieving double-sided heat dissipation, having high heat dissipation efficiency, and greatly improving the stability of the power module 100. Multiple heat sinks 300 share the same water inlet 301 and the same water outlet 302. The structure of each heat sink 300 is as shown in FIG. Figure 2B As shown, a groove structure is formed inside the heat sink 300, and a heat dissipation fin 16 is provided in the groove to improve the heat exchange efficiency between the heat sink 300 and the power module 100, thereby improving the heat dissipation capacity of the heat sink 300. Figure 2A and Figure 2B The heat sink 300 shown has a complex structure, is difficult to install, and has high process requirements, so the cost is relatively high.

[0050] Based on the above description, the embodiments of the present application propose an improved power module and a packaging method thereof, which can achieve double-sided heat dissipation while having a simple structure and low process requirements, thereby reducing costs and facilitating wider applications.

[0051] Figure 3 2 is a cross-sectional schematic diagram of a power module assembly provided in an embodiment of the present application.

[0052] like Figure 3As shown, the power module assembly of the embodiment of the present application includes a power module 100 and a heat sink 400. The power module 100 includes a chip stack and a seal 17. The chip stack includes a semiconductor chip 11, a packaging substrate 12, and a heat dissipation substrate 15 stacked in sequence perpendicular to the chip plane. The semiconductor chip 11 is, for example, an IGBT chip or a SiC chip. The packaging substrate 12 is soldered to the top and bottom of the semiconductor chip 11. The packaging substrate 12 is, for example, a DBC (direct-bonded copper) substrate. Exemplarily, the packaging substrate 12 includes two upper and lower metal layers 13 and an insulating layer 14 located in the middle. The metal layer 13 is, for example, a copper layer, and the insulating layer 14 is, for example, a ceramic layer or a ceramic substrate. A heat dissipation substrate 15 is installed on the side of the packaging substrate 12 away from the semiconductor chip 11. Heat dissipation fins (pinfins) 16 are formed on the heat dissipation substrate 15. The heat dissipation substrate 15 is made of a material with good heat dissipation capability, such as copper or aluminum. The heat dissipation substrate 16 can be integrally formed with the adjacent metal layer or soldered. The sealing member 17 is used to encapsulate the semiconductor chip 11, the package substrate 12 and at least a portion of the heat dissipation substrate 15. Figure 3 As shown, the heat dissipation fins 16 of the bottom heat dissipation substrate 15 are not covered by the seal 17 but are exposed to the outside. A cooling channel 18 is formed inside the seal 17. The cooling channel 18 extends upward from the side of the bottom where the power terminals are not formed to the top, passes through the heat dissipation fins 16 of the top heat dissipation substrate 15, and then extends downward from the top to the other side of the bottom where the power terminals are not formed.

[0053] It should be understood that Figure 3 The power modules shown also have Figure 1A and Figure 1B The power terminals are shown (not shown in the cross-sectional view, the cross-section is taken along the two side surfaces where no terminals are formed), and cooling channels are formed in the top of the power module 100 and the two side surfaces where no power terminals are formed.

[0054] The radiator 400 has a water inlet 401 and a water outlet 402. Multiple power modules 100 can share the same radiator 400. Figure 3As shown, the heat sink 400 has a mounting groove 403. When the power module 100 is installed in the mounting groove 403, the bottom of the power module 100 and the heat sink 400 form a bottom cooling channel. After the coolant (such as water) enters from the water inlet 401, the coolant flows from the bottom of the power module 100 (i.e., the mounting groove 403) and removes the heat generated by the semiconductor chip 11 by exchanging heat with the heat dissipation substrate 15 at the bottom. On the other hand, the coolant flows along the cooling channel 18 in the seal 17 and removes the heat generated by the semiconductor chip 11 by exchanging heat with the heat dissipation substrate 15 at the top. In other words, the power module 100 of the embodiment of the present application can achieve double-sided heat dissipation on both the top and bottom sides while using only one heat sink. It has a simple structure, low process requirements, and therefore low cost.

[0055] It should be understood that a plurality of mounting slots 403 may be formed on the heat sink 400 to mount a plurality of power modules 100 . The plurality of mounting slots 403 are connected to each other via the communication openings 404 .

[0056] Figure 4 1 is a schematic structural diagram of a mold for packaging a power module provided in an embodiment of the present application; Figure 5 1 is a schematic structural diagram of a mold for packaging a power module provided in an embodiment of the present application from another perspective; Figure 6 It is a structural schematic diagram of a mold for packaging a power module provided in an embodiment of the present application, wherein a water channel mold is inserted into a bottom mold.

[0057] like Figures 4 to 6 As shown, the mold 500 for packaging a power module provided in an embodiment of the present application includes a top mold 510, a bottom mold 520, a left water channel mold 530, and a right water channel mold 540. The top mold 510 and the bottom mold 520 correspond to each other in structure, and a cavity is formed inside them to accommodate the power module 100 to be packaged. The size of the cavity corresponds to the desired size of the power module after packaging. Figure 3 Taking the power module 100 shown as an example, the size of the seal 17 corresponds to the size of the cavity. The top mold 510 is a hollow shell structure with an opening at the bottom, while the bottom mold 520 is a hollow shell structure with openings at both the top and bottom. The top opening of the bottom mold 520 is the same size as the bottom opening of the top mold 510. The bottom opening of the bottom mold 520 corresponds to the size of the heat dissipation fins 16 at the bottom of the power module 100. When the module 100 to be packaged is placed in the mold 500, the heat dissipation fins 16 at the bottom of the power module just extend out of the bottom opening of the bottom mold 520.

[0058] like Figures 4 to 6As shown, two water channel mold insertion openings 511 are provided at the top of the top mold 510, and two corresponding water channel mold insertion openings 521 are provided at the bottom of the bottom mold 520. These are used to respectively allow the left water channel mold 530 and the right water channel mold 540 to be inserted into the receiving cavity formed by the top mold 510 and the bottom mold 520. When potting material is injected into the receiving cavity, the left water channel mold 530 and the right water channel mold 540 inside the receiving cavity prevent the potting material from forming at the water channel location.

[0059] like Figures 4 to 6 As shown, two potting material injection ports 512 are provided on the top of the top mold 510 , through which potting material can be injected into the mold, thereby completing the packaging of the power module through a potting process.

[0060] like Figures 4 to 6 As shown, a terminal extension groove 513 is provided at the bottom of the side of the top mold 510, and a terminal extension groove 523 is correspondingly provided at the top of the side of the bottom mold 520. When the top mold 510 and the bottom mold 520 are assembled together, the terminal extension groove 513 and the corresponding terminal extension 523 form an opening for the terminal to extend from the inside of the mold, so that the terminal is located outside the mold during the packaging process, avoiding the formation of potting material on the terminal.

[0061] It should be understood that in Figures 4 to 6 Only the protruding slots or openings for the power terminals are schematically shown in the figure. However, when the power module 100 includes signal terminals, the mold 500 is also provided with corresponding slots or openings for the signal terminals to protrude.

[0062] The mold for packaging the power module in the embodiment of the present application has a simple structure, and an internal cooling channel can be formed in the seal when the mold is used for packaging, so that the power module can achieve double-sided heat dissipation through only one heat sink.

[0063] Figure 7 This is a schematic flow chart of a packaging method for a power module provided in an embodiment of the present application.

[0064] like Figure 7 As shown, the packaging method provided in the embodiment of the present application includes:

[0065] Step S701, using a removable and moldable material to cover the heat dissipation fins on the top of the power module and shape them;

[0066] Step S702 , placing the power module into the mold, and adjusting the position of the water channel mold so that the water channel mold is aligned with the removable moldable material formed on the top;

[0067] Step S703, completing the packaging by using a mold through a potting process;

[0068] Step S704 , removing the mold and introducing high-pressure liquid into the cooling channel in the power module to flush out the removable and moldable material.

[0069] In step S701, the power module to be packaged is fixed by removable moldable material so that the removable moldable material completely covers the heat dissipation fins on the top of the power module, and the removable moldable material is shaped. The shape after molding is as follows: Figure 8 In this step, the gap where the moldable material completely covers the top heat sink fins and the areas on both sides and the top of the heat sink fins can be removed. For details, see Figure 11 As shown. The removable moldable material can be any suitable material that is easy to mold and remove, such as sticky wet sand. For example, to increase the stickiness of the sand, clay can be mixed into the sand, and the clay can be used to bond the sand and other mixtures to ensure viscosity.

[0070] In step S702, the power module is placed in the mold, and the position of the water channel mold is adjusted so that the water channel mold is aligned with the removable moldable material formed on the top. Figures 9 to 11 Specifically, the power module can be placed in the bottom mold 520 first, and the bottom heat dissipation fins 16 of the power module extend from the bottom opening of the bottom mold 520 to the outside of the mold. At the same time, the power terminals extend to the outside of the mold through the terminal extension grooves 523. Then, the left water channel mold 530 and the right water channel mold 540 are inserted into the water channel mold insertion port 521 of the bottom mold 520, and the position (or height) of the water channel mold is adjusted to align the water channel mold with the top shaped sand, as shown in FIG. Figure 11 As shown, the sides of the left water channel mold 530 and the right water channel mold 540 are fitted with the shaped removable formable material 20, and the tops are flush with the shaped removable formable material 20. The top of the shaped removable formable material 20 is higher than the top heat dissipation fin 16, so that a heat dissipation fin 16 can be formed during the potting process. Figure 3 The top portion of the cooling channel 18 in the seal 17 is shown. Finally, the top mold 512 is snapped onto the bottom mold 520 to complete the placement of the power module.

[0071] In step S703, the mold is encapsulated through a potting process. Specifically, a potting material such as epoxy resin is first injected into the mold through the potting material injection port 512 to encapsulate the power module in the potting material. The potting material is then cured by heating or ultraviolet irradiation to complete the encapsulation.

[0072] In step S704, the mold is first removed, that is, the packaged power module is removed from the mold. Then, a high-pressure liquid flow, such as high-pressure water, is introduced into the cooling channel within the power module to clean out the removable moldable material (e.g., sand). Specifically, the removable moldable material (e.g., sand) within the power module is cleaned out using high-pressure water.

[0073] The packaging method of the power module of the embodiment of the present application uses the mold provided in the present application for packaging to form an internal cooling channel in the seal, so that the power module can achieve double-sided heat dissipation through only one heat sink.

[0074] As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A mold for packaging a power module, wherein the power module comprises a semiconductor chip located in the middle and heat dissipation substrates located on the top and bottom of the semiconductor chip, wherein heat dissipation fins are formed on the heat dissipation substrates, characterized in that: The mold comprises: A top mold, wherein the top mold is a hollow shell structure with an open bottom, and a potting material injection port and two water channel insertion ports are formed on the top of the top mold; A bottom mold, wherein the bottom mold is a hollow shell structure with openings at the top and bottom. The opening at the top of the bottom mold corresponds to the opening at the bottom of the top mold. The opening at the bottom of the bottom mold corresponds to the size of the heat dissipation fins at the bottom of the power module. Two water channel insertion openings are correspondingly formed at the bottom of the bottom mold. The bottom mold and the bottom mold together form an internal cavity for placing the power module. Two water channel molds can be inserted into the mold through the water channel insertion port of the top mold or the bottom mold.

2. The mold according to claim 1, characterized in that Terminal extension grooves are formed on the side surfaces of the top mold and the bottom mold adjacent to the water channel insertion port, and the terminal extension grooves of the top mold and the terminal extension grooves of the bottom mold together form an opening for the terminals of the power module to extend to the outside of the mold.

3. A packaging method for a power module, wherein the power module comprises a semiconductor chip located in the middle, and heat dissipation substrates located on the top and bottom of the semiconductor chip, wherein heat dissipation fins are formed on the heat dissipation substrates, characterized in that: The packaging method comprises: Cover the heat dissipation fins of the heat dissipation substrate on the top of the power module with a removable formable material and shape it; Placing the power module into the mold according to claim 1 or 2, and adjusting the position of the water channel mold so that the water channel mold is aligned with the removable moldable material formed on the top; Using the mold to complete the packaging through a potting process; The mold is removed, and a high-pressure liquid flow is introduced into the cooling channel in the power module to flush out the removable moldable material.

4. The packaging method according to claim 3, wherein: The height of the shaped removable formable material is higher than the height of the heat dissipation fins of the heat dissipation substrate on the top of the power module.

5. A power module assembly, characterized in that: include: A power module and a heat sink packaged using the packaging method according to claim 3 or 4, wherein the power module comprises: semiconductor chips; A packaging substrate, wherein one packaging substrate is welded on the top and bottom of the semiconductor chip respectively; a heat dissipation substrate, formed on a side of the packaging substrate away from the semiconductor chip, with heat dissipation fins formed on the heat dissipation substrate; a sealing member, the sealing member wrapping the semiconductor chip, the packaging substrate, and the heat dissipation substrate excluding the heat dissipation fins, wherein the sealing member has cooling channels formed therein that communicate with the left and right sides and the top of the power module; The power module is mounted on the radiator, and the heat dissipation substrate at the bottom of the power module and the radiator form a bottom cooling channel.

6. The power module assembly according to claim 5, characterized in that: At least two power modules are mounted on the radiator.

7. A power device, characterized in that: Includes the power module assembly according to claim 5 or 6.

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