Silicon carbide power module and power device

Abstract

The utility model provides a silicon carbide power module and a power device. The silicon carbide power module comprises a substrate, wherein an inlet end copper-clad area and a third copper-clad area which are symmetrical relative to a symmetric axis are formed on the surface of one side of the substrate; the power field-effect tube groups comprise an upper bridge field-effect tube group and a lower bridge field-effect tube group which are complementary and are symmetrically arranged relative to the symmetric axis; the upper bridge field-effect tube group comprises a power field-effect tube which is bridged between an inlet end copper-clad region and a third copper-clad region on one side of the symmetry axis; and the lower bridge field-effect tube group comprises a power field-effect tube which is bridged between the incoming end copper-clad region and the third copper-clad region on the other side of the symmetry axis. According to the utility model, through the upper bridge arm and the lower bridge arm of the half-bridge power module which are physically and symmetrically arranged, the irregular influence of mutual stray inductance on the two bridge arms during time-sharing conduction is reduced, the ripple quality of output current is favorably improved, and a foundation is laid for obtaining high-quality stable direct current output for subsequent circuit rectification.

Description

Technical Field

[0001] The utility model relates to the technical field of silicon carbide power devices, and in particular to a silicon carbide power module and a power device. Background Art

[0002] Up to now, major companies have gradually discovered from the (HybirdPACK Drive) packaged silicon carbide modules that this packaging process cannot fully bring out the advantages of silicon carbide materials. The new generation of silicon carbide devices made by this packaging process still have room for improvement in terms of operating junction temperature, stray inductance, PC power cycle, H3TRB high temperature and high humidity reverse bias reliability, etc.

[0003] With the development of the electric vehicle market, the requirements of car products for power modules are getting higher and higher, requiring power modules to have higher reliability and provide smoother DC power output. Under the growing market demand, existing silicon carbide devices have been difficult to meet the requirements. One of the main aspects affected is that in similar power modules, with the high-frequency switching of silicon carbide devices, obvious stray inductance will be generated, affecting the output current quality. On the other hand, there is also the problem of uneven heating of the substrate. The invention patent entitled "A Reconfigurable Three-Level Power Module" with publication number CN117748895A has disclosed a power module with a half-bridge structure. We know that the topology of a typical half-bridge circuit has a symmetrical structure, but the device layout in the technical solution disclosed in the comparative document is scattered and clustered. The spatial inductance influence between each group of devices is difficult to balance and avoid, and it is difficult to effectively maintain the stability of the output ripple when the output current requirement is high. Moreover, since each group of silicon carbide devices is dispersed on the substrate, this will also cause the substrate to be in uneven heating working conditions for a long time. Utility Model Content

[0004] In order to reduce the influence of stray inductance on output ripple, provide high-quality current output, and ensure the consistency of heat dissipation of junction temperature of each chip, the utility model provides a silicon carbide power module and a power device.

[0005] The present application provides a silicon carbide power module, comprising a substrate, characterized in that the substrate has a symmetry axis;

[0006] A third copper-clad area, a first copper-clad area and a second copper-clad area are formed on the surface of the substrate, and the second copper-clad area, the first copper-clad area and the third copper-clad area are all symmetrically arranged relative to the symmetry axis;

[0007] The third copper-clad area, the first copper-clad area and the second copper-clad area form two groups of conversion areas that are symmetrical with respect to the symmetry axis;

[0008] A plurality of power field effect tube groups are arranged in the conversion area, and the power field effect tube groups include complementary outer bridge field effect tubes and inner bridge field effect tubes.

[0009] Preferably, the plurality of power field effect transistor groups in the two groups of conversion regions are symmetrically arranged relative to the substrate.

[0010] Preferably, inside the conversion area, the first copper clad area, the third copper clad area, and the second copper clad area are arranged in sequence.

[0011] Preferably, the conversion area is at least in a part of the copper-clad area where the field effect transistor is mounted, and the first copper-clad area and the second copper-clad area are symmetrically arranged relative to the third copper-clad area.

[0012] Preferably, the first copper clad area is electrically connected to the first terminal, the second copper clad area is electrically connected to the second terminal, and the third copper clad area is electrically connected to the third terminal.

[0013] Preferably, it comprises a first control pin and a second control pin, the first control pin is electrically connected to the gate of the external bridge field effect transistor, and the second control pin is electrically connected to the gate of the internal bridge field effect transistor.

[0014] Preferably, a protective resistor is connected in series to the gate of the outer bridge field effect transistor and / or the inner bridge field effect transistor.

[0015] Preferably, it also includes a plurality of monitoring pins, wherein the monitoring pins are connected to the corresponding copper-clad area to obtain the circuit status of the copper-clad area.

[0016] The utility model also provides a silicon carbide power device, characterized in that it comprises the silicon carbide power module described in any one of the above items, and the periphery of the silicon carbide power module is encapsulated with a solid plastic sealing layer.

[0017] Preferably, a heat dissipation base plate is disposed in contact with the back side of the substrate of the silicon carbide power module.

[0018] The utility model reduces the irregular influence of the stray inductance of the two bridge arms when they are conducting in time-sharing mode by means of a half-bridge power module that is physically symmetrically arranged. Due to the adoption of a symmetrical layout scheme, the influence of the stray inductance between the two bridge arms can be better balanced and reduced, which is conducive to improving the ripple quality of the output current and laying a foundation for subsequent circuit rectification to obtain high-quality stable DC output. Moreover, a similar layout scheme is also conducive to balancing the heating of the substrate and avoiding excessive local temperature differences in the substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram of an embodiment of a silicon carbide power module of the present utility model;

[0020] Figure 2A schematic diagram of a further improvement of the silicon carbide power module of the utility model;

[0021] Figure 3 A schematic diagram of a silicon carbide power device of the present utility model;

[0022] Figure 4 It is a schematic structural diagram of the silicon carbide power device of the utility model.

[0023] In the figure:

[0024] 1: substrate; 111: first copper-clad area; 112: second copper-clad area; 12: third copper-clad area; 13: power field-effect transistor group; 131: external bridge field-effect transistor; 132: internal bridge field-effect transistor; 14: wiring terminal; 141: third terminal; 142: first terminal; 143: second terminal; 144: control pin; 151: protection resistor; 1Q: conversion area; 1S: symmetry axis; 2: heat dissipation base plate; 3: solid plastic sealing layer; 441: first control pin; 442: second control pin. DETAILED DESCRIPTION

[0025] The following is a detailed description of the present invention in conjunction with the accompanying drawings and specific embodiments. In this specification, the size ratios in the drawings do not represent the actual size ratios, but are only used to reflect the relative position relationship and connection relationship between the components. Components with the same name or the same number represent similar or identical structures and are only for illustrative purposes.

[0026] Considering that the silicon carbide-based half-bridge circuit itself has a good symmetrical topology, the technology of the utility model aims to design a silicon carbide half-bridge module with a symmetrical layout based on this point, and optimize the device performance through the symmetrical layout of the module. Figure 1It is a schematic layout diagram of the silicon carbide power module of the utility model. It includes a substrate 1, a copper-clad pattern is formed on one side of the surface of the substrate 1 for conducting current, the substrate 1 has a symmetry axis 1S, and a conversion area 1Q symmetrical to the symmetry axis 1S is formed on its surface on both sides of the symmetry axis 1S, and a half-bridge conversion circuit is formed in the conversion area 1Q. Specifically, a third copper-clad area 12, a first copper-clad area 111 and a second copper-clad area 112 are formed on the surface of the substrate 1. The third copper-clad area 12, the first copper-clad area 111 and the second copper-clad area 112 are symmetrically arranged relative to the symmetry axis 1S. Several groups of power field effect tube groups 13 are arranged in the conversion area 1Q, and the power field effect tube group 13 includes an external bridge field effect tube 131 and an internal bridge field effect tube 132. The source and drain of the external bridge field effect tube 131 are electrically connected between the second copper-clad area 112 and the third copper-clad area 12, the source is electrically connected to the third copper-clad area 12, and the drain is electrically connected to the second copper-clad area 112. The source and drain of the inner bridge field effect transistor 132 are electrically connected between the first copper clad area 111 and the third copper clad area 12, the source is electrically connected to the first copper clad area 111, and the drain is electrically connected to the third copper clad area 12. The outer bridge field effect transistor 131 and the inner bridge field effect transistor 132 are complementary, and complementarity means that the types of the outer bridge field effect transistor 131 and the inner bridge field effect transistor 132 are opposite, so under the gate drive signal, the outer bridge field effect transistor 131 and the inner bridge field effect transistor 132 are respectively in the on and off states, realizing the time-sharing conduction of the outer bridge arm and the inner bridge arm, and realizing the power conversion function. The physical layout of the circuit is symmetrical, and there are symmetrical conductive paths on both sides relative to the symmetry axis 1S at any time, which is conducive to stabilizing and balancing the influence of the field effect transistor on the output current of the circuit under high-frequency switching, so as to achieve the purpose of improving the quality of the output current, and is conducive to uniform heating of the substrate 1, simplifying the heat dissipation design. Generally, multiple groups of power field effect transistor groups 13 are provided. For example, we have Figure 1 As can be seen, multiple groups connected in parallel can increase the current rating of the module accordingly.

[0027] Specifically, inside the conversion area 1Q, the first copper-clad area 111, the third copper-clad area 12 and the second copper-clad area 112 are generally arranged in sequence. At this time, the third copper-clad area 12 is located between the first copper-clad area 111 and the second copper-clad area 112, so as to facilitate the arrangement of the external bridge field effect transistor 131 and the internal bridge field effect transistor 132 electrically connected to the third copper-clad area 12. Preferably, at least in the copper-clad area where the field effect transistor is installed, the first copper-clad area 111 and the second copper-clad area 112 are still symmetrically arranged relative to the third copper-clad area 12, and the external bridge field effect transistor 131 and the internal bridge field effect transistor 132 in the power field effect transistor group 13 are also symmetrically installed relative to the third copper-clad area 12. This balances the parasitic inductance generated by the high-frequency time-sharing conduction of the internal and external bridges and the internal bridges in the conversion area 1Q, and is also conducive to the uniform distribution of the field effect transistors and the uniform heating of the substrate 1.

[0028] As for the above-mentioned silicon carbide half-bridge power module, under the control of the gate voltage, when the outer bridge field effect tube 131 is turned on, the complementary inner bridge field effect tube 132 is disconnected. At this time, only the outer bridge is turned on; the inner bridge is turned on. Therefore, the potential of the third copper-clad area 12 changes periodically relative to the potential of the second copper-clad area 112 and the first copper-clad area 111, thereby realizing the driving function of the circuit. Accordingly, the first terminal 142 and the second terminal 143 can be connected in the first copper-clad area 111 and the second copper-clad area 112, respectively, and the third terminal 141 is electrically connected to the third copper-clad area 12, and the input terminal and the third terminal are used to connect to the external circuit. Since the second terminal 143 and the first terminal 142 are both connected to the input side of the circuit, the layout is preferably arranged on the same side of the substrate 1 for easy wiring. For example, in actual use, three modules are used side by side, and the second terminal 143 will be connected to the second terminal 143 of another module.

[0029] In all the above schemes, the on-off control of the circuit is realized by the input signal of the control pin 144, and the voltage signal of the control pin 144 acts on the outer bridge field effect transistor 131 and the inner bridge field effect transistor 132. It is not excluded that the control pin 144 is set separately to multiple. In actual use, the input signal is applied to the gate and the source at the same time, that is, the VGS signal. Figure 2 A solution is provided in which the control pin 144 includes a plurality of discretely controlled pins. The control pin 144 includes a first control pin 441 and a second control pin 442. For a solution having a plurality of power field effect tube groups 13, the control pin 144 is uniformly connected to the gates of the external bridge field effect tubes 131 or the internal bridge field effect tubes 132 of all power field effect tube groups 13. Alternatively, the gates of all external bridge field effect tubes 131 are uniformly connected by the first control pin 441, and the gates of the internal bridge field effect tubes 132 are uniformly connected by the second control pin 442. A protection resistor 151 may be connected in series between each power field effect tube and the control pin to prevent the gate of the power resistor from being subjected to excessive pressure. Optionally, Figure 2 The schematic diagram also includes other signal pins, which can be connected to the corresponding copper-clad area to obtain the circuit status of the copper-clad area, thereby achieving the purpose of external monitoring.

[0030] The substrate 1 of the silicon carbide half-bridge power module can adopt an AMB (active metal brazing) insulating ceramic substrate (its material is silicon nitride, aluminum nitride, etc.), and its double-sided copper is used for circuit etching of the module, and the ceramic material in the middle plays an insulating role. Metal bonding wires (aluminum wire, aluminum-clad copper wire, copper wire) are used for electrical connection between chips, and DTS copper foil is used for electrical connection between metal bonding wires and chips. The silicon carbide chip adopts the third-generation wide bandgap semiconductor chip, and the physical connection between the chip and the AMB is completed by solid-state silver pressure sintering. The third terminal 141, the first terminal 142, the second terminal 143, the control pin 144, etc. are all metal lead frames (all copper, all copper gold-plated, etc.), which serve as electrical terminals to lead out the module electrical interface for connection with the outside world.

[0031] The above silicon carbide module mainly achieves the optimization of module stray inductance through strict symmetrical setting in the physical sense of the module, which is beneficial to improving the output quality, and the power field effect tubes are arranged in an orderly manner on the substrate 1, which is beneficial to the uniform heat conduction of the substrate and improves the heat dissipation efficiency. The performance of silicon carbide materials can be better utilized and the module reliability can be improved through the improvement and optimization of the design; in addition, the symmetrical design of the substrate layout has a great improvement in chip current sharing, module thermal resistance, module stray inductance and other aspects.

[0032] Based on the above silicon carbide module, the utility model also provides a silicon carbide power device, such as Figure 4 As shown, a heat dissipation base plate 2 (copper nickel-plated, etc.) is provided on the back contact of the above-mentioned symmetrically designed silicon carbide half-bridge power module. The heat dissipation base plate 2 is used to transfer the heat of the module to the outside world, and a solid plastic sealing layer 3 is encapsulated on the periphery of the silicon carbide half-bridge power module. The solid plastic sealing layer 3 encapsulates the base plate of the heat dissipation base plate 2 and the substrate 1 together inside, and while isolating the substrate 1 encapsulation, it also realizes the fixed connection between the substrate 1 and the heat dissipation base plate 2. The solid plastic sealing layer 3 strictly and completely isolates the silicon carbide power module from the outside world, and only exposes the corresponding terminals and pins, which plays an insulating role between the inside of the module and the outside world. The integrated silicon carbide power device has the characteristics of high reliability, low operating junction temperature, fast heat dissipation, and low stray inductance. It is a targeted design of the applicant and can improve the performance characteristics of the single-sided half-bridge module.

[0033] The above content is only a description of the preferred implementation mode of the utility model, and does not limit the scope of the utility model. Without departing from the design spirit of the utility model, various modifications and improvements made to the technical solution of the utility model by ordinary technicians in this field should fall within the protection scope determined by the claims of the utility model.

Claims

1. A silicon carbide power module, comprising a substrate (1), characterized in that: The substrate (1) has a symmetry axis (1S); A third copper-clad area (12), a first copper-clad area (111) and a second copper-clad area (112) are formed on the surface of the substrate (1), and the second copper-clad area (112), the first copper-clad area (111) and the third copper-clad area (12) are all arranged symmetrically with respect to the symmetry axis (1S); The third copper-clad area (12), the first copper-clad area (111) and the second copper-clad area (112) form two groups of conversion areas (1Q) that are symmetrical with respect to the symmetry axis (1S); A plurality of power field effect tube groups (13) are arranged in the conversion area (1Q), and the power field effect tube groups (13) include complementary outer bridge field effect tubes (131) and inner bridge field effect tubes (132).

2. The silicon carbide power module according to claim 1, characterized in that: The plurality of power field effect tube groups (13) in the two groups of conversion areas (1Q) are symmetrically arranged relative to the substrate (1).

3. The silicon carbide power module according to claim 1, characterized in that: Inside the conversion area (1Q), the first copper clad area (111), the third copper clad area (12), and the second copper clad area (112) are arranged in sequence.

4. The silicon carbide power module according to claim 3, characterized in that: The conversion area (1Q) is at least partially located in the copper-clad area where the field effect tube is installed, and the first copper-clad area (111) and the second copper-clad area (112) are symmetrically arranged relative to the third copper-clad area (12).

5. The silicon carbide power module according to claim 1, characterized in that: The first copper clad area (111) is electrically connected to the first terminal (142), the second copper clad area (112) is electrically connected to the second terminal (143), and the third copper clad area (12) is electrically connected to the third terminal (141).

6. The silicon carbide power module according to claim 1, characterized in that: It comprises a first control pin (441) and a second control pin (442), wherein the first control pin (441) is electrically connected to the gate of the external bridge field effect transistor (131), and the second control pin (442) is electrically connected to the gate of the internal bridge field effect transistor (132).

7. The silicon carbide power module according to claim 6, characterized in that: A protective resistor (151) is connected in series to the gate of the external bridge field effect transistor (131) and / or the internal bridge field effect transistor (132).

8. The silicon carbide power module according to claim 1, characterized in that: It also includes a plurality of monitoring pins, which are connected to the corresponding copper-clad area to obtain the circuit status of the copper-clad area.

9. A silicon carbide power device, characterized in that: It comprises a silicon carbide power module as claimed in any one of claims 1 to 8, wherein the silicon carbide power module is peripherally encapsulated with a solid plastic sealing layer (3).

10. The silicon carbide power device according to claim 9, characterized in that: The back side of the substrate (1) of the silicon carbide power module is in contact with a heat dissipation base plate (2).

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