Power module, flip heat dissipation packaging method and inverter

Abstract

The invention discloses a power module, an inverted heat dissipation packaging method and an inverter, and relates to the field of power module packaging, and the key points of the technical scheme are that the power module comprises an upper substrate and a lower substrate; wherein a rectangular body with an interval space is formed between the upper substrate and the lower substrate through a frame; a first semiconductor device is arranged on the lower bottom surface of the upper substrate; a second semiconductor device is arranged on the upper surface of the lower substrate; the output of the first semiconductor device is connected with the input of the second semiconductor device through a copper bar.

Description

Technical Field

[0001] This invention relates to the field of power module packaging, and more specifically, to a power module, a flip-chip thermal packaging method, and an inverter. Background Technology

[0002] Packaging and heat dissipation technology for power modules is a core support for ensuring the efficient and reliable operation of power electronic systems. Its importance stems from the urgent needs of modern energy transition and technological upgrading: the core semiconductor devices in the module (such as IGBTs, MOSFETs, and diodes) generate a large amount of heat during operation. If this heat cannot be dissipated in a timely and effective manner, it will lead to an increase in junction temperature, which in turn will cause a decrease in efficiency, performance degradation, and reduced reliability, and even permanent damage to the devices.

[0003] The current key bottleneck in heat dissipation in packaging lies in the fact that traditional single-sided heat dissipation packaging relies on bonding wires for electrical interconnection, and its heat can only be dissipated through a single path via the bottom direct-bonded copper substrate (DBC). The heat generated by the top chip needs to be dissipated through multiple interfaces to the back copper substrate, resulting in generally high junction-case thermal resistance, which has become a core obstacle restricting the development of high power density modules. Summary of the Invention

[0004] The purpose of this invention is to provide a power module, a flip-chip heat dissipation packaging method, and an inverter, which solves the problem of weak single-sided heat dissipation capability of power modules in the prior art.

[0005] The above-mentioned technical objective of the present invention is achieved through the following technical solution:

[0006] In a first aspect, the present invention provides a power module, the power module including an upper substrate and a lower substrate; wherein the upper substrate and the lower substrate are connected by a frame to form a rectangular body with a space between them;

[0007] A first semiconductor device is disposed on the bottom surface of the upper substrate;

[0008] A second semiconductor device is disposed on the upper surface of the lower substrate;

[0009] The output of the first semiconductor device and the input of the second semiconductor device are connected by a copper busbar.

[0010] In one implementation, the power module further includes at least one water-cooling component arranged sequentially along the bottom surface of the lower substrate, one vertical side of the rectangular body, and the upper surface of the upper substrate; wherein the water outlet and water inlet of the water-cooling component are flat and elongated elliptical in shape.

[0011] In one implementation, the power module further includes an air inlet and an air outlet respectively on the vertical surfaces of both sides of the rectangular body where the water-cooling component is not provided.

[0012] In one implementation, the first semiconductor device and the second semiconductor device are any one or more of diode chips, IGBT chips, and MOSFET chips.

[0013] In one implementation, the electrode regions of the first semiconductor device and the second semiconductor device are connected by metal bonding wires.

[0014] In one implementation, the first semiconductor device and the second semiconductor device are arranged opposite to each other.

[0015] In one implementation, both the upper substrate and the lower substrate are copper substrates.

[0016] A second aspect of the present invention provides a flip-chip thermal packaging method for a power module, used to package a power module as provided in the first aspect of the present invention, the method comprising:

[0017] The upper and lower substrates are arranged from top to bottom at preset intervals.

[0018] The upper and lower substrates are fixed by a frame to form a rectangular body with spaced intervals.

[0019] A first semiconductor device is disposed on the bottom surface of the upper substrate;

[0020] A second semiconductor device is disposed on the upper surface of the lower substrate;

[0021] A copper busbar is used to connect the output of the first semiconductor device to the input of the second semiconductor device.

[0022] In one implementation, metal bonding wires are used to connect the electrode regions of the first semiconductor device and the second semiconductor device.

[0023] A third aspect of the present invention provides an inverter comprising a power module as provided in the first aspect of the present invention.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] This invention proposes a power module and a flip-chip thermal packaging method. By fully utilizing vertical space through a three-dimensional layout, it significantly reduces the planar dimensions of semiconductor devices. This structure also shortens the spacing between power terminals, effectively suppressing parasitic parameters (such as parasitic inductance), meeting the design requirements of module miniaturization and high power density. This invention further develops a customized thermal packaging structure, innovatively integrating the advantages of liquid cooling and air cooling technologies. A liquid cooling plate is integrated directly beneath the chip, significantly increasing its contact area with the copper substrate and enhancing the heat conduction efficiency in high heat flux areas. Air cooling channels are set between the stacked module layers, guiding the directional flow of cold air through external window structures to achieve auxiliary heat dissipation in medium and low temperature areas. This solution constructs a breakthrough thermal architecture, providing key technical support for power module packaging design and helping power electronic devices achieve higher power density and compact integration. Attached Figure Description

[0026] The accompanying drawings, which are included to provide a further understanding of embodiments of the invention and form part of this application, do not constitute a limitation thereof. In the drawings:

[0027] Figure 1 A schematic diagram of a power module provided in an embodiment of the present invention;

[0028] Figure 2 This is another structural schematic diagram of a power module provided in an embodiment of the present invention. Detailed Implementation

[0029] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of this invention are only for explaining this invention and are not intended to limit this invention.

[0030] It should be noted that the terms "comprising" or "may include" used in the various embodiments of this application indicate the presence of the claimed function, operation, or element, and do not limit the addition of one or more functions, operations, or elements. Furthermore, as used in the various embodiments of this application, the terms "comprising," "having," and their cognates are intended only to indicate a specific feature, number, step, operation, element, component, or combination of the foregoing, and should not be construed as primarily excluding the presence of one or more other features, numbers, steps, operations, elements, components, or combinations of the foregoing, or adding one or more combinations of the foregoing.

[0031] It should be understood that terms such as "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0032] Current power modules typically employ single-sided soldering for common single-sided chip bonding. A typical power module structure usually has seven layers from bottom to top: a base plate, a soldering layer, a DBC substrate (including a ceramic insulating layer), a chip soldering layer, a semiconductor chip, a bonding layer, and a top cover plate. Liquid cooling or air cooling is added below the base plate for heat dissipation. However, the single-layer module design and single-sided heat dissipation limit the development of high-power-density modules.

[0033] To address the aforementioned technical issues, this application provides a flip-chip thermal packaging method for power modules, as well as a connection method between power modules, which can further save module space.

[0034] Figure 1 This is a schematic diagram of a power module provided in an embodiment of the present invention, as shown below. Figure 1 As shown, the power module includes an upper substrate and a lower substrate; wherein, the upper substrate and the lower substrate are connected by a frame to form a rectangular body with a space between them; a first semiconductor device is disposed on the bottom surface of the upper substrate; a second semiconductor device is disposed on the upper surface of the lower substrate; the output of the first semiconductor device and the input of the second semiconductor device are connected by a copper busbar.

[0035] Specifically, this embodiment takes a power module with a half-bridge MOSFET as an example. As those skilled in the art can know, controllable switching devices such as diode chips and IGBT chips can also be used here.

[0036] like Figure 1 As shown, the power module provided by the present invention consists of upper and lower half-bridges, with the neutral point connected by a copper busbar and externally supported and fixed by a frame, thereby forming a rectangular body with spaced intervals. Figure 1 To simplify the design of a half-bridge consisting of two MOSFET chips connected in parallel, this embodiment utilizes metal bonding wires to connect the gate (G), drain (D), and source (S) regions of the MOSFETs for the electrode connections between the first and second semiconductor devices. While common modules are single-layer structures, to improve space utilization, the upper and lower half-bridge modules are stacked, with the tops of the chips facing each other. In this configuration, the top of the module is the upper substrate, with its chip area facing inwards, and the bottom of the module is the lower substrate, with its area facing outwards. Figure 1The bottom right corner shows a schematic diagram of the parallel half-bridge module. Therefore, the power module proposed in this invention features a vertically stacked packaging architecture. Through the vertical interconnect structure, the lateral extension space of the module is reduced, achieving miniaturization and reduced parasitic inductance, thus meeting the requirements for high power density.

[0037] It is common knowledge in this technical field that both the upper and lower substrates are copper substrates, and this embodiment does not impose any additional limitations.

[0038] The purpose of placing the first and second semiconductor devices opposite each other is to maintain the spatial stability of the entire power module. It also aims to reduce space requirements and the amount of air needed for cooling, as the relative placement allows for heat dissipation through airflow from the center.

[0039] In some embodiments, the power module further includes at least one water-cooling component disposed sequentially along the bottom surface of the lower substrate, one vertical surface of the rectangular body, and the upper surface of the upper substrate; wherein the water outlet and water inlet of the water-cooling component are flat and elongated elliptical in shape.

[0040] Specifically, such as Figure 2 As shown, liquid cooling is used to dissipate heat from the power module. Our current module design is a stacked structure, with all copper base plates facing outwards. A water-cooling component is installed directly below the lower substrate. The water outlet and inlet here can be made into a flat, elongated ellipse to increase the contact area with the upper and lower substrates; alternatively, it can be made into a single component connecting the upper and lower parts to remove the heat generated by the power module.

[0041] It should be noted that there are currently various flow channel shapes for water-cooled heat dissipation components, such as series-parallel combined flow channels, S-shaped flow channels, etc. Therefore, this embodiment does not impose specific limitations on the internal shape of the proposed water-cooled component, as long as heat dissipation can be achieved.

[0042] In some embodiments, the power module further includes an air inlet and an air outlet respectively provided on the vertical surfaces on both sides of the rectangular body where the water-cooling component is not provided.

[0043] Specifically, such as Figure 2 As shown, based on the liquid cooling described above, air cooling is further employed to dissipate heat from the power module. There is a free-flowing air space within the stacked half-bridge modules (i.e., the interlayer space). Two windows are opened in the package casing here, namely the air inlet and the air outlet, to facilitate airflow and remove the heat generated during semiconductor device operation. It is understood that the shape of the air inlet and outlet can be either grid-like or strip-like; this embodiment does not impose specific limitations.

[0044] It is understood that there can be one or more air outlets and air inlets; this embodiment does not impose any specific limitations.

[0045] In summary, compared with the water cooling and air cooling described in the above embodiments, this invention proposes a hybrid enhanced heat dissipation solution, which innovatively designs a flat and elongated elliptical liquid cooling channel to increase the contact area and specifically cover the high-heat areas of the chip; it integrates an interlayer forced air cooling system to achieve coordinated heat dissipation from one side to three sides through multi-directional airflow channels.

[0046] This invention also provides a flip-chip thermal packaging method for a power module, used to package a power module as described in the above embodiments. The method includes: setting an upper substrate and a lower substrate from top to bottom at a preset interval height; fixing the upper substrate and the lower substrate with a frame to form a rectangular body with an interval space; setting a first semiconductor device on the bottom surface of the upper substrate; setting a second semiconductor device on the upper surface of the lower substrate; and connecting the output of the first semiconductor device and the input of the second semiconductor device with a copper busbar.

[0047] Accordingly, the flip-chip thermal packaging method proposed in this invention fully utilizes vertical space through a three-dimensional layout, significantly reducing the planar dimensions of the half-bridge module. This structure also shortens the power terminal spacing, effectively suppressing parasitic parameters (such as parasitic inductance), meeting the design requirements of module miniaturization and high power density. This invention further develops a customized thermal packaging structure, innovatively integrating the advantages of liquid cooling and air cooling technologies. A liquid cooling plate is integrated directly beneath the chip, significantly increasing its contact area with the copper substrate and enhancing the heat conduction efficiency in high heat flux areas. Air cooling channels are set between the stacked module layers, guiding the directional flow of cold air through external window structures to achieve auxiliary heat dissipation in medium and low temperature areas. This solution constructs a groundbreaking thermal architecture, providing key technical support for power module packaging design and helping power electronic devices achieve higher power density and compact integration.

[0048] In some embodiments, metal bonding wires are used to connect the electrode regions of the first semiconductor device and the second semiconductor device.

[0049] This invention also provides an inverter composed of a power module as described in the above embodiments.

[0050] Specifically, inverters can be classified according to their output waveform, power supply type, and application scenario. Examples include square wave inverters, modified sine wave inverters (or quasi-sine wave inverters), photovoltaic inverters, energy storage inverters, and vehicle inverters. Photovoltaic inverters are specifically designed for solar power generation systems, converting the direct current (DC) generated by solar panels into alternating current (AC). They typically also feature maximum power point tracking (MPPT) to maximize the power generation efficiency of the solar panels. Energy storage inverters are used in battery energy storage systems, responsible for bidirectional energy conversion between the battery (DC) and the grid (AC). They can both invert power to loads and rectify power to charge batteries. Vehicle inverters connect to the car's cigarette lighter or battery, converting 12V / 24V DC power to 220V AC power for use by in-vehicle electrical appliances.

[0051] Accordingly, since the power module fully utilizes vertical space through a three-dimensional layout, the planar dimensions of the half-bridge module are significantly reduced. This structure also shortens the spacing between power terminals, effectively suppressing parasitic parameters (such as parasitic inductance), meeting the design requirements of module miniaturization and high power density. This invention further develops a customized heat dissipation packaging structure, innovatively integrating the advantages of liquid cooling and air cooling technologies. A liquid cooling plate is integrated directly beneath the chip, significantly increasing its contact area with the copper substrate and enhancing the heat conduction efficiency in high heat flux areas. Air cooling channels are set between the stacked module layers, guiding the directional flow of cold air through external window structures to achieve auxiliary heat dissipation in medium and low temperature areas. This solution constructs a groundbreaking heat dissipation architecture, providing key technical support for power module packaging design and helping power electronic devices achieve higher power density and compact integration.

[0052] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A power module, characterized in that, The power module includes an upper substrate and a lower substrate; wherein the upper substrate and the lower substrate are connected by a frame to form a rectangular body with a space between them; A first semiconductor device is disposed on the bottom surface of the upper substrate; A second semiconductor device is disposed on the upper surface of the lower substrate; The output of the first semiconductor device and the input of the second semiconductor device are connected by a copper busbar.

2. A power module according to claim 1, characterized in that, The power module further includes at least one water-cooling component arranged sequentially along the bottom surface of the lower substrate, one vertical side of the rectangular body, and the upper surface of the upper substrate; wherein the water outlet and water inlet of the water-cooling component are flat and elongated elliptical in shape.

3. A power module according to claim 2, characterized in that, The power module also includes air inlets and air outlets on the vertical surfaces of both sides of the rectangular body where the water-cooling components are not located.

4. A power module according to claim 1, characterized in that, The first semiconductor device and the second semiconductor device are any one or more of the following three types: diode chip, IGBT chip, and MOSFET chip.

5. A power module according to claim 1, characterized in that, The electrode regions of the first semiconductor device and the second semiconductor device are connected by metal bonding wires.

6. A power module according to claim 1, characterized in that, The first semiconductor device and the second semiconductor device are arranged opposite to each other.

7. A power module according to claim 1, characterized in that, Both the upper substrate and the lower substrate are copper substrates.

8. A flip-chip thermal packaging method for a power module, used to package a power module as described in any one of claims 1 to 7, characterized in that the method... include: The upper and lower substrates are arranged from top to bottom at preset intervals. The upper and lower substrates are fixed by a frame to form a rectangular body with spaced intervals. A first semiconductor device is disposed on the bottom surface of the upper substrate; A second semiconductor device is disposed on the upper surface of the lower substrate; A copper busbar is used to connect the output of the first semiconductor device to the input of the second semiconductor device.

9. A flip-chip heat dissipation packaging method for a power module according to claim 8, characterized in that, The electrode regions of the first semiconductor device and the second semiconductor device are connected by metal bonding wires.

10. An inverter comprising a power module as described in any one of claims 1 to 7.

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