A power module and a power device

Abstract

The utility model relates to the field of semiconductor integrated circuit processing especially relates to a power module and power equipment. The utility model embodiment provides a kind of power module, including at least one power device, heat-conducting ceramic plate and plastic package, and power device is packaged in the one side of heat-conducting ceramic plate by plastic package, and the bottom of plastic package is connected with heat-conducting ceramic plate;Power device includes power chip, gate metal piece, source metal piece and drain metal piece, the surface of power chip opposite heat-conducting ceramic plate has gate and source, and the surface of power chip towards heat-conducting ceramic plate has drain;One end of gate metal piece is electrically contacted with gate, one end of source metal piece is electrically contacted with source, the surface of heat-conducting ceramic plate is formed with conductive layer, drain is electrically contacted with conductive layer, one end of drain metal piece is electrically contacted with conductive layer, and the other end of gate metal piece, source metal piece and drain metal piece exposes from plastic package.

Description

Technical Field

[0001] This utility model relates to the field of semiconductor integrated circuit processing, and in particular to a power module and a power device. Background Technology

[0002] Power semiconductor devices, as core components in power electronic converters, are now widely used in inverters, battery management, electric drive systems, frequency converters, and other fields in new energy systems. Silicon carbide (SiC), with its wide bandgap, strong critical breakdown field, and high thermal conductivity, is a typical representative material of semiconductors. It has advantages such as high voltage, low loss, and high temperature resistance, which places higher demands on the packaging structure of power semiconductor devices.

[0003] Traditional power module packaging structures mainly include a substrate, gate metal leads, source metal leads, a semiconductor chip, bonding wires, and a plastic encapsulation shell. The semiconductor chip is soldered to the upper surface of the substrate. The gate metal leads are connected to the gate of the semiconductor chip via bonding wires, the source metal leads are connected to the source of the semiconductor chip via bonding wires, and the drain metal leads are connected to the drain of the semiconductor chip via bonding wires. The plastic encapsulation shell encapsulates the substrate and bonding wires, with the ends of each metal lead protruding from the plastic encapsulation shell. A heat sink is fixed to the back of the substrate using a thermal pad, and the power module dissipates heat through the heat sink.

[0004] The aforementioned power modules have long current paths introduced by metal bonding wires and metal pins, resulting in large parasitic inductance and significant heat loss. This can easily lead to heat dissipation failure and insulation failure of the insulation layer, failing to meet the heat dissipation and insulation requirements of power devices under high-voltage conditions. Utility Model Content

[0005] The technical problem to be solved by this utility model is: to provide a power module and power device that address the problem that existing power modules cannot meet the heat dissipation and insulation requirements of power devices under high voltage conditions.

[0006] To address the aforementioned problems, this utility model provides a power module comprising at least one power device, a thermally conductive ceramic plate, and a molding compound. The molding compound encapsulates the power device on one side of the thermally conductive ceramic plate along its thickness direction, and the bottom of the molding compound is connected to the thermally conductive ceramic plate. The power device includes a power chip, a gate metal element, a source metal element, and a drain metal element. The surface of the power chip facing away from the thermally conductive ceramic plate has a gate and a source, and the surface of the power chip facing the thermally conductive ceramic plate has a drain.

[0007] One end of the gate metal element is electrically contacted with the gate of the power chip, and one end of the source metal element is electrically contacted with the source of the power chip. A conductive layer is formed on the surface of the thermally conductive ceramic plate facing the power chip. The drain of the power chip is electrically contacted with the conductive layer, and one end of the drain metal element is electrically contacted with the conductive layer. The other ends of the gate metal element, the source metal element, and the drain metal element are exposed from the molding compound. The surface of the thermally conductive ceramic plate facing away from the power chip is adapted to connect a heat dissipation device.

[0008] Optionally, the gate metal element and the source metal element are located on the side of the power chip facing away from the thermally conductive ceramic plate, and the other ends of the drain metal element, the gate metal element, and the source metal element are all exposed from the surface of the molding compound facing away from the thermally conductive ceramic plate.

[0009] Optionally, the drain metal element extends along the thickness direction of the thermally conductive ceramic plate.

[0010] Optionally, the gate metal element is a gate metal layer formed by sintering a layer of metal material, and the source metal element is a source metal layer formed by sintering a layer of metal material. The gate metal layer and the source metal layer are electrically insulated from each other by the encapsulation.

[0011] Optionally, the thickness t1 of the gate metal layer is 10~100μm, and the thickness t2 of the source metal layer is 10~100μm.

[0012] Optionally, the gate metal layer is welded to the surface of the power chip facing away from the thermally conductive ceramic plate, and the source metal layer is welded to the surface of the power chip facing away from the thermally conductive ceramic plate.

[0013] Optionally, the other end surface of the drain metal element, the other end surface of the gate metal element, and the other end surface of the source metal element are in the same plane.

[0014] Optionally, a metal connection layer is formed on the surface of the thermally conductive ceramic plate facing away from the power chip, and the metal connection layer is used to weld the heat dissipation device of the power device.

[0015] Optionally, the molding compound includes a first molding portion and a second molding portion connected to the bottom of the first molding portion. The first molding portion encapsulates the power chip, the gate metal component, the source metal component, and the drain metal component. The second molding portion encapsulates the outer peripheral surface of the thermally conductive ceramic plate, so that the surface of the thermally conductive ceramic plate facing away from the power chip is exposed.

[0016] On the other hand, this utility model embodiment provides a power device, including a circuit board and the aforementioned power module, wherein the power module is embedded in the circuit board.

[0017] Optionally, it also includes a heat dissipation device, which is mounted on the surface of the thermally conductive ceramic plate facing away from the power chip.

[0018] This utility model provides a power module in which the power device dissipates heat outward through a heat dissipation path of power chip-conductive layer-thermal conductive ceramic plate. Compared with traditional organic substrates, the thermal conductive ceramic plate has better thermal conductivity and electrical insulation properties. While dissipating heat from the power device, the thermal conductive ceramic plate also isolates the electrical connection between the power device and the heat dissipation device. The source of the power device on the back of the thermal conductive ceramic plate can be directly led outward through the other end of the source metal component, and the gate can be directly led outward through the other end of the gate metal component, eliminating the need for metal bonding wires. This shortens the current path, reduces parasitic inductance, and minimizes heat loss. The drain metal component is electrically connected to the drain of the power chip through the conductive layer. The drain of the power chip can be led out through the other end of the drain metal component. Compared to metal bonding wires, the conductive layer has a larger cross-sectional area. Due to the skin effect, the parasitic inductance introduced by the conductive layer is reduced, further minimizing heat loss. The parasitic inductance of power devices is reduced, heat loss is reduced, and the possibility of thermal conductive ceramic plates being broken down and failing in heat dissipation under high voltage conditions is reduced. The heat dissipation and insulation reliability of power modules are improved, which can meet the requirements of high voltage conditions for the insulation reliability and heat dissipation of power modules. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the power module provided in one embodiment of the present invention.

[0021] The reference numerals in the accompanying drawings are as follows:

[0022] 1. Power chip; 2. Gate metal component; 3. Source metal component; 4. Drain metal component; 5. Molded package; 6. Thermally conductive ceramic plate; 7. Conductive layer; 8. Metal interconnect layer. Detailed Implementation

[0023] To make the technical problems solved, technical solutions, and beneficial effects of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0024] Traditional power module packaging structures mainly include a substrate, gate metal leads, source metal leads, a semiconductor chip, bonding wires, and a plastic encapsulation shell. The semiconductor chip is soldered to the upper surface of the substrate. The gate metal leads are connected to the gate of the semiconductor chip via bonding wires, the source metal leads are connected to the source of the semiconductor chip via bonding wires, and the drain metal leads are connected to the drain of the semiconductor chip via bonding wires. The plastic encapsulation shell encapsulates the substrate and bonding wires, with the ends of each metal lead protruding from the plastic encapsulation shell. A heat sink is fixed to the back of the substrate using a thermal pad, and the power module dissipates heat through the heat sink.

[0025] The aforementioned power module has a long current path due to the metal bonding wires and metal pins, which introduces a large parasitic inductance. This leads to increased heat generation in the power device and increases the risk of breakdown of the insulation layer (including the heat sink and the organic insulation layer of the substrate). It can also cause the heat dissipation and insulation performance of the insulation layer to fail. Therefore, the packaging structure of the aforementioned power module cannot be used to package silicon carbide power devices under high voltage conditions and cannot meet the insulation reliability and heat dissipation performance requirements of silicon carbide power devices.

[0026] To address the aforementioned problems, this utility model provides a power module.

[0027] like Figure 1 As shown, an embodiment of this utility model provides a power module including at least one power device, a thermally conductive ceramic plate 6, and a molding compound 5. The molding compound 5 encapsulates the power device on one side of the thermally conductive ceramic plate 6 along its thickness direction. The bottom of the molding compound 5 is connected to the thermally conductive ceramic plate 6 to electrically insulate the power chip 1 from the outside environment. The power chip 1 can be a silicon carbide chip, which has advantages such as high voltage, low loss, and high temperature resistance.

[0028] The power device includes a power chip 1, a gate metal part 2, a source metal part 3, and a drain metal part 4. The surface of the back heat-conducting ceramic plate 6 of the power chip 1 has a gate and a source, and the surface of the front heat-conducting ceramic plate 6 of the power chip 1 has a drain.

[0029] One end of the gate metal component 2 is electrically contacted with the gate of the power chip 1, and one end of the source metal component 3 is electrically contacted with the source of the power chip 1. A conductive layer 7 is formed on the surface of the thermally conductive ceramic plate 6 facing the power chip 1. The drain of the power chip 1 is electrically contacted with the conductive layer 7, and one end of the drain metal component 4 is electrically contacted with the conductive layer 7. The other ends of the gate metal component 2, the source metal component 3, and the drain metal component 4 are exposed from the molding compound 5. The surface of the thermally conductive ceramic plate 6 facing away from the power chip 1 is used to connect a heat dissipation device. The gate metal component 2 is used for gate signal control of the power chip 1, the source metal component 3 is used for source signal control of the power chip 1, and the drain metal component 4 is used for drain signal control of the power chip 1.

[0030] Understandably, the molding compound 5 is formed by encapsulating the power device with insulating molding material to ensure electrical insulation between the power device and the outside world. The electrical insulation coefficient of the molding compound is typically ≥1×10^ 10 Ω·cm. The thermally conductive ceramic plate 6, while serving as an electrical insulator, can also draw away the heat from the power chip 1 and dissipate it using a heat dissipation device. The thermal conductivity of the thermally conductive ceramic plate 6 is typically ≥5W / (mK). -1 .

[0031] Specifically, the molding compound 5 and the thermally conductive ceramic plate 6 connected to the bottom of the molding compound 5 encapsulate the power device. The power device dissipates heat outward through the heat dissipation path of power chip 1-conductive layer 7-thermally conductive ceramic plate 6. Compared with traditional organic substrates, the thermally conductive ceramic plate 6 has better thermal conductivity and electrical insulation performance. While dissipating the heat of the power device, the thermally conductive ceramic plate 6 isolates the electrical connection between the power device and the heat dissipation device, and there is no need to attach a thermally conductive insulating pad between the organic substrate and the heat dissipation device for insulation treatment as in the prior art.

[0032] The molding compound 5 supports and fixes the power chip 1, the source metal part 3, the gate metal part 2, and the drain metal part 4. One end of the source metal part 3 is directly in electrical contact with the source of the power device, and one end of the gate metal part 2 is directly in electrical contact with the gate of the power device. Therefore, the source of the power device can be directly led out through the other end of the source metal part 3, and the gate can be directly led out through the other end of the gate metal part 2, without the need for bonding with metal bonding wires, so as to shorten the current path, reduce parasitic inductance, and reduce heat loss.

[0033] One end of the drain metal part 4 is in direct electrical contact with the conductive layer 7 on the surface of the thermally conductive ceramic plate 6, and the drain of the power chip 1 is in direct electrical contact with the conductive layer 7 of the thermally conductive ceramic plate 6. Therefore, the drain metal part 4 and the drain of the power chip 1 are electrically connected through the conductive layer 7, and the drain of the power chip 1 can be led out through the other end of the drain metal part 4. Compared with the metal bonding wire, the cross-sectional area of ​​the conductive layer 7 is larger. Due to the skin effect, the parasitic inductance introduced by the conductive layer 7 is reduced, thereby reducing heat loss.

[0034] The parasitic inductance introduced by the power devices is reduced, the heat loss is reduced, the possibility of the thermally conductive ceramic plate 6 being broken down and failing in heat dissipation under high voltage conditions is reduced, the heat dissipation and insulation reliability of the power module are improved, and it can better meet the requirements of automotive main drive inverters and DC-DC converters for the insulation reliability and heat dissipation of the power module.

[0035] In one embodiment, the gate metal element 2 and the source metal element 3 are located on the same side of the power chip 1 away from the thermally conductive ceramic plate 6. The other ends of the drain metal element 4, the gate metal element 2, and the source metal element 3 are all exposed from the surface of the molding compound 5 away from the thermally conductive ceramic plate 6, so that the three electrodes of the power chip 1 are led outward from the top of the power module. The heat dissipation device is located on the side of the power module away from the power chip 1. The gate metal element 2, the source metal element 3, and the drain metal element 4, which introduce parasitic inductance, are led out to the side away from the heat dissipation device, increasing the distance from the heat dissipation device and further reducing the possibility of the parasitic inductance breaking through the molding compound 5 and the thermally conductive ceramic plate 6, causing the insulation between the power chip 1 and the heat dissipation device to fail.

[0036] In one embodiment, the power chip 1 is welded and fixed on the thermally conductive ceramic plate 6, and a welding layer is formed between the power chip 1 and the thermally conductive ceramic plate 6.

[0037] In one embodiment, the drain metal element 4 extends along the thickness direction of the thermally conductive ceramic plate 6 to further reduce the length of the drain metal element 4, thereby further reducing the parasitic inductance introduced by the drain metal element 4.

[0038] In one embodiment, the drain metal part 4 is a copper pillar that extends along the thickness direction of the thermally conductive ceramic plate 6. The bottom end of the copper pillar is welded to the conductive layer 7, and the top end of the copper pillar is exposed from the encapsulation 5.

[0039] In one embodiment, the other end surface of the drain metal element 4, the other end surface of the gate metal element 2, and the other end surface of the source metal element 3 are in the same plane.

[0040] The molding body 5 is usually formed by molding the power device with molding material. When the other end surface of the drain metal part 4, the other end surface of the gate metal part 2 and the other end surface of the source metal part 3 are in the same plane, the shape of the power device is more regular, which can simplify the molding mold and reduce the molding difficulty.

[0041] Moreover, when the power module is embedded in the circuit board, it is easy to route traces on the end faces of the drain metal part 4, the gate metal part 2 and the source metal part 3 located on the same plane.

[0042] In one embodiment, the gate metal element 2 is a gate metal layer formed by sintering a single layer of metal material, and the source metal element 3 is a source metal layer formed by sintering a single layer of metal material. The gate metal layer and the source metal layer are electrically insulated from each other by a molding compound 5. The sintered gate metal layer and source metal layer have a small thickness, which further reduces the current path, reduces the introduced parasitic inductance, and reduces heat loss.

[0043] In one embodiment, the thickness t1 of the gate metal layer is 10~100μm and the thickness t2 of the source metal layer is 10~100μm. If the thickness of the gate metal layer and the source metal layer is too small, it will increase the process difficulty and limit its current carrying capacity. If the thickness of the gate metal layer and the source metal layer is too large, it will lead to an increase in parasitic inductance. Therefore, in order to balance the process difficulty, current carrying capacity and parasitic inductance, the thickness of the gate metal layer and the source metal layer is limited to 10~100μm.

[0044] In one embodiment, the gate metal layer is soldered to the surface of the back heat-conducting ceramic plate 6 of the power chip 1, and the source metal layer is soldered to the surface of the back heat-conducting ceramic plate 6 of the power chip 1. A solder layer is formed between the gate metal layer and the power chip 1, and a solder layer is formed between the source metal layer and the power chip 1.

[0045] In one embodiment, the cross-sectional area of ​​the gate metal layer is smaller than that of the source metal layer. Since the gate size of the power chip 1 is smaller than the source size, the cross-sectional area of ​​the gate metal layer is designed to be smaller than that of the source metal layer to match the corresponding electrode size.

[0046] In one embodiment, both the gate metal layer and the source metal layer are copper layers.

[0047] In one embodiment, a metal connection layer 8 is formed on the surface of the thermally conductive ceramic plate 6 facing away from the power chip 1. The metal connection layer 8 is used to weld the heat dissipation device of the power device. The metal connection layer 8 provides a connection surface for the heat dissipation device, which facilitates the welding and fixing of the heat dissipation device to the back side of the thermally conductive ceramic plate 6.

[0048] In one embodiment, the thermally conductive ceramic plate 6 is a double-sided copper-clad ceramic plate, with one side of the copper layer forming the conductive layer 7 and the other side forming the metal connection layer 8. This double-sided copper-clad ceramic plate can be an aluminum nitride ceramic copper-clad plate or an alumina ceramic copper-clad plate.

[0049] In one embodiment, the molding compound 5 includes a first molding portion and a second molding portion connected to the bottom of the first molding portion. The first molding portion encapsulates the power chip 1, the gate metal part 2, the source metal part 3, and the drain metal part 4. The second molding portion encapsulates the opposite ends of the thermally conductive ceramic plate 6, further improving the overall insulation reliability of the power module, so that only the surface of the thermally conductive ceramic plate 6 facing away from the power chip 1 is exposed.

[0050] In one embodiment, such as Figure 1 As shown, only one power device is set. It should be noted that in actual design, two or more can be designed as needed. Taking two power devices as an example, the two power devices can share one thermally conductive ceramic plate 6, or two thermally conductive ceramic plates 6 can be set, and the two power devices are respectively encapsulated on the corresponding thermally conductive ceramic plates 6.

[0051] Specifically, the power module of this utility model is manufactured through the following steps:

[0052] S1: Obtain power chip 1, thermally conductive ceramic plate 6, source metal layer, gate metal layer and copper pillar; wherein, the source metal layer and gate metal layer are formed by sintering;

[0053] S2: The source metal layer is welded to the upper surface of the power chip 1, the gate metal layer is welded to the upper surface of the power chip 1, the source metal layer is in electrical contact with the source of the power chip 1, and the gate metal layer is in electrical contact with the gate of the power chip 1; wherein, the upper surface of the power chip 1 has a source and a gate.

[0054] S3: The lower surface of the power chip 1 is welded onto the conductive layer 7 formed on the surface of the thermally conductive ceramic plate 6, and the drain of the power chip 1 is in electrical contact with the conductive layer 7; wherein, the lower surface of the power chip 1 has a drain.

[0055] S4: Weld one end of the copper pillar to the conductive layer 7;

[0056] S4: The source metal layer, gate metal layer, copper pillar and power chip 1 are encapsulated in a molding compound 5 formed of molding compound material. The surfaces of the source metal layer, gate metal layer and copper pillar facing away from the thermally conductive ceramic plate 6 are exposed from the molding compound 5. The bottom of the molding compound 5 is connected to the thermally conductive ceramic plate 6. The surface of the thermally conductive ceramic plate 6 facing away from the power chip 1 is exposed from the molding compound 5, thus obtaining the above power module.

[0057] The molding process is common knowledge in this field and will not be elaborated upon here.

[0058] It should be noted that the above manufacturing method is only one embodiment, and other methods can also be used to obtain the above power module. For example, during molding, only the power chip 1 can be molded, and a first sintering tank, a second sintering tank, and a third sintering tank can be formed on the molding body 5 using a mold. Copper paste is injected into the first sintering tank and sintered to form a copper pillar. Metal paste is injected into the second sintering tank to form a source metal layer. Metal paste is injected into the third sintering tank to form a gate metal layer.

[0059] In addition, one embodiment of the present invention provides a power device, which includes a circuit board and a power module as described in any of the above embodiments. The power module is embedded in the circuit board, and the other end of the drain metal part 4, the other end of the source metal part 3, and the other end of the gate metal part 2 exposed from the plastic package 5 are electrically connected to the conductive lines of the circuit board.

[0060] The power module is embedded in the circuit board, which can shorten the current path, reduce parasitic inductance, and reduce heat loss. The heat generated by the embedded power module can be directly conducted to the inner heat dissipation copper foil or metal substrate of the circuit board (such as aluminum-based or copper-based PCB), which has an efficient heat dissipation path and better heat dissipation effect.

[0061] In one embodiment, a heat dissipation device is also included, which is mounted on the surface of the thermally conductive ceramic plate 6 facing away from the power device.

[0062] Specifically, a connecting metal layer is formed on the surface of the thermally conductive ceramic plate 6 facing away from the power device, and the heat dissipation device is welded onto the connecting metal layer.

[0063] The above-described embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model, and should all be included within the protection scope of this utility model.

Claims

1. A power module, characterized in that, The device includes at least one power device, a thermally conductive ceramic plate, and a molding compound. The molding compound encapsulates the power device on one side of the thermally conductive ceramic plate in the thickness direction, and the bottom of the molding compound is connected to the thermally conductive ceramic plate. The power device includes a power chip, a gate metal element, a source metal element, and a drain metal element. The surface of the power chip facing away from the thermally conductive ceramic plate has a gate and a source, and the surface of the power chip facing the thermally conductive ceramic plate has a drain. One end of the gate metal element is electrically contacted with the gate of the power chip, and one end of the source metal element is electrically contacted with the source of the power chip. A conductive layer is formed on the surface of the thermally conductive ceramic plate facing the power chip. The drain of the power chip is electrically contacted with the conductive layer, and one end of the drain metal element is electrically contacted with the conductive layer. The other ends of the gate metal element, the source metal element, and the drain metal element are exposed from the molding compound. The surface of the thermally conductive ceramic plate facing away from the power chip is adapted to connect a heat dissipation device.

2. The power module according to claim 1, characterized in that, The gate metal element and the source metal element are located on the side of the power chip facing away from the thermally conductive ceramic plate. The other ends of the drain metal element, the gate metal element, and the source metal element are all exposed from the surface of the molding compound facing away from the thermally conductive ceramic plate.

3. The power module according to claim 2, characterized in that, The drain metal element extends along the thickness direction of the thermally conductive ceramic plate.

4. The power module according to claim 2, characterized in that, The gate metal element is a gate metal layer formed by sintering a layer of metal material, and the source metal element is a source metal layer formed by sintering a layer of metal material. The gate metal layer and the source metal layer are electrically insulated from each other by the encapsulation.

5. The power module according to claim 4, characterized in that, The thickness t1 of the gate metal layer is 10~100μm, and the thickness t2 of the source metal layer is 10~100μm.

6. The power module according to claim 5, characterized in that, The gate metal layer is welded to the surface of the power chip facing away from the thermally conductive ceramic plate, and the source metal layer is welded to the surface of the power chip facing away from the thermally conductive ceramic plate.

7. The power module according to claim 2, characterized in that, The other end surfaces of the drain metal element, the gate metal element, and the source metal element are in the same plane.

8. The power module according to any one of claims 1 to 7, characterized in that, A metal connection layer is formed on the surface of the thermally conductive ceramic plate facing away from the power chip. The metal connection layer is used to weld the heat dissipation device of the power equipment.

9. The power module according to any one of claims 1 to 7, characterized in that, The molding compound includes a first molding portion and a second molding portion connected to the bottom of the first molding portion. The first molding portion encapsulates the power chip, gate metal component, source metal component, and drain metal component. The second molding portion encapsulates the outer peripheral surface of the thermally conductive ceramic plate, so that the surface of the thermally conductive ceramic plate facing away from the power chip is exposed.

10. A power device, characterized in that, The invention includes a circuit board and a power module as described in any one of claims 1 to 9, wherein the power module is embedded in the circuit board.

11. The power device according to claim 10, characterized in that, It also includes a heat dissipation device, which is installed on the surface of the thermally conductive ceramic plate facing away from the power chip.

Images