Power module with double-lining-plate structure and electronic device
By using flexible elastic connectors between the chip and the second liner, the existing double liner structure power module has been solved, and a double liner structure power module with high power density, low stray inductance and high reliability is realized.
Patent Information
- Application Number
- CN202411881133.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-19
- Publication Date
- 2025-04-08
AI Technical Summary
While improving the heat dissipation performance and mechanical strength, the existing double-lined panel structure power module has low power density, high cost and insufficient reliability. Especially when temperature cycling, the welding layer is prone to high stress and reliability failure.
An elastic connection is provided between the upper surface of the chip and the lower surface of the second liner plate by a flexible connection method. The lower copper layer of the second liner plate is conductive, and the deformation height difference between the first liner plate and the second liner plate is absorbed, so as to ensure the reliability of the connection through downspring pressure.
It improves power density, reduces the overall size of the module, enhances current sharing ability, reduces stray inductance, and significantly improves the reliability life of the solder layer.
Smart Images
Figure CN119786444A_ABST
Abstract
Description
Technical Field
[0001] The present application belongs to the field of semiconductors, and in particular relates to a double-liner structure power module and an electronic device. Background Art
[0002] The double liner structure in the SiC module can improve the heat dissipation performance and mechanical strength of the module, ensuring the reliability and stability of the module.
[0003] There are two types of double-liner structures in the prior art. One is that the chip and the second-layer liner are placed on the same first liner; the chip and the first-layer liner are interconnected using a solder layer, and the SiC chip gate is connected to the copper layer on the second liner through a binding wire, and the copper layer on the second liner only provides a path for the signal. Although this method has a lower process difficulty, since the chip and the second-layer liner are not stacked in the Z direction but are laid flat on a plane, the size of the first liner is not fully utilized, resulting in a lower power density and not conducive to reducing costs.
[0004] Another double-liner structure is that the lower surface of the chip is connected to the first liner, the upper surface of the chip is directly connected to the copper layer under the second liner, and the chip gate is connected to the copper layer on the second liner through a binding wire. Therefore, the copper layer under the liner is used to carry large currents, and the upper copper layer only provides a path for signals, so as to separate large currents and signal currents and reduce the coupling between large currents and signal currents. However, since both liner layers will have warping problems, the connection between the chip and the second liner becomes difficult, and it is easy to have problems where some chips can be connected while others cannot; and the upper surface of the chip is rigidly connected to the copper layer under the liner. When undergoing temperature cycles, due to the different thermal expansion coefficients of the chip and the liner, the solder layer of the chip and the liner is subjected to large stress, and reliability is easily failed.
[0005] Therefore, a double liner structure for a power module is needed to solve the above problems. Summary of the invention
[0006] In order to address the deficiencies of the prior art, the present application provides a double-liner structure power module and electronic device, which solves the problems of high power density, low stray inductance and high reliability of the double-liner power module by adopting a flexible connection between the upper surface of the chip and the lower surface of the second liner.
[0007] The technical effects to be achieved by this application are achieved through the following solutions:
[0008] According to the first aspect of the present application, a double-liner structure power module is provided, comprising a first liner, a chip arranged on the first liner, and a second liner stacked above the chip, wherein the first liner, the chip and the second liner are all plastic-encapsulated in a plastic encapsulation body, and an elastic connector is arranged between the second liner and the chip, wherein the elastic connector is made of a conductive material, so that the source of the chip is electrically connected to the copper layer on the bottom surface of the second liner, and the gate of the chip is electrically connected to the copper layer on the top surface of the second liner through a binding wire.
[0009] Preferably, the elastic connector comprises an upper connecting copper layer, an elastic layer and a lower connecting copper layer, the upper connecting copper layer and the lower connecting copper layer are conductively connected, and the elastic layer is at least used for elastic connection between the upper connecting copper layer and the lower connecting copper layer.
[0010] Preferably, the elastic layer is a corrugated copper plate, and the corrugated copper plate is electrically connected to the upper connection copper layer and the lower connection copper layer along a corrugation direction.
[0011] Preferably, the elastic layer further includes a spring, and the spring is supported between the upper connection copper layer and the lower connection copper layer.
[0012] Preferably, the spring always applies a downward thrust to the lower connecting copper layer.
[0013] Preferably, conductive columns are provided on both sides and in the middle of the bottom of the second lining plate, and the length of the conductive columns is smaller than the length of the spring in a natural state.
[0014] Preferably, the spring sleeve is arranged outside the corrugated copper plate.
[0015] Preferably, there are a plurality of chips arranged in a matrix on the first backing plate, and each chip is provided with a corresponding elastic connector.
[0016] Preferably, the chips are arranged in two rows, and a plurality of signal pins are arranged on the second backing plate, and the signal pins are arranged along the middle of the second backing plate.
[0017] According to a second aspect of the present application, an electronic device is provided, which adopts the above-mentioned double liner structure power module.
[0018] According to one embodiment of the present application, the beneficial effects of adopting the double liner structure power module are:
[0019] The lower copper layer of the second liner is used for conduction instead of the area of the first liner, which improves the power density and reduces the overall size of the module.
[0020] The second lining plate and the chip are connected by an elastic connector, which absorbs the height difference between the first lining plate and the second lining plate caused by deformation. The spring pressure ensures that the lower connection copper layer is reliably connected to all chip sources.
[0021] All currents are collected on the lower copper layer of the second liner. The voltage balancing effect of the copper layer helps to balance the current of chips at different positions, thus improving the current output capacity of the module.
[0022] During module operation, after temperature cycling, since the second liner is not directly connected to the chip surface but flexibly connected through elastic connectors, the stress caused by the CTE mismatch between the two is greatly reduced, greatly improving the reliability life of the solder layer. BRIEF DESCRIPTION OF THE DRAWINGS
[0023] In order to more clearly illustrate the embodiments of the present application or the existing technical solutions, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.
[0024] Figure 1 This is a schematic diagram of a double-liner structure power module in one embodiment of the present application;
[0025] Figure 2 for Figure 1 A schematic diagram of the structure of the first lining plate;
[0026] Figure 3 for Figure 1 The structural schematic diagram of the second lining plate;
[0027] Figure 4 for Figure 1 Schematic diagram of the structure of the elastic connector. DETAILED DESCRIPTION
[0028] In order to make the purpose, technical solution and advantages of the present application clearer, the technical solution of the present application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.
[0029] like Figures 1 to 4As shown, a double-liner structure power module in one embodiment of the present application includes a first liner 100, a chip 110 arranged on the first liner 100, and a second liner 200 stacked above the chip 110. The first liner 100, the chip 110 and the second liner 200 are all plastic-encapsulated in a plastic encapsulation body 300. An elastic connector 400 is arranged between the second liner 200 and the chip 110. The elastic connector 400 is made of conductive material, so that the source of the chip 110 is electrically connected to the bottom copper layer of the second liner 200, and the gate of the chip 110 is electrically connected to the top copper layer of the second liner 200 through a binding wire 230.
[0030] Through this embodiment, the second substrate 200 is stacked with the source electrode of the chip 110, and the lower copper layer of the second substrate 200 is used for conduction, and the area of the first substrate 100 is no longer used. There is space to arrange more chips 110, thereby improving the power density and reducing the overall size of the module.
[0031] The second liner 200 and the chip 110 are connected by an elastic connector 400. The elastic connector 400 absorbs the height difference between the first liner 100 and the second liner 200 caused by deformation, thereby avoiding poor contact of the chip 110 caused by warping of the first liner 100 and the second liner 200, thereby improving the reliability of the connection.
[0032] Moreover, all the current is collected in the lower copper layer of the second liner 200 , and the voltage equalization effect of the copper layer is beneficial to current equalization of the chips 110 at different positions, thereby improving the current output capacity of the module.
[0033] During module operation, after temperature cycling, since the second liner 200 is not directly connected to the surface of the chip 110 but is flexibly connected through the elastic connector 400, the stress generated by the mismatch in expansion coefficients between the two is greatly reduced, thereby greatly improving the reliability life of the solder layer.
[0034] In one embodiment of the present application, the elastic connector 400 includes an upper connection copper layer 410, an elastic layer, and a lower connection copper layer 420. The upper connection copper layer 410 and the lower connection copper layer 420 are electrically connected, and the elastic layer is at least used for elastic connection between the upper connection copper layer 410 and the lower connection copper layer 420. The upper connection copper layer 410 and the lower connection copper layer 420 are electrically connected, and while ensuring the conductive performance, deformation errors such as warping can also be absorbed by the elastic layer.
[0035] In one embodiment of the present application, the elastic layer is a corrugated copper plate 431, which is electrically connected to the upper connecting copper layer 410 and the lower connecting copper layer 420 along the corrugation direction. The corrugated copper plate 431 can be stretched and compressed to adapt to deformation while ensuring the quality of the electrical connection.
[0036] In one embodiment of the present application, the elastic layer also includes a spring 432, and the spring 432 is supported between the upper connection copper layer 410 and the lower connection copper layer 420. The spring 432 always applies a downward thrust to the lower connection copper layer 420. The downward pressure of the spring 432 ensures that the lower connection copper layer 420 is reliably connected to the source of all chips 110. The spring 432 is set outside the corrugated copper plate 431, which can improve the overall compactness and reduce the occupied space, so that it is suitable for use in a compact power module. The spring 432 can also conduct electricity at the same time, so that the device can be compressed and stretched, and can also transfer large currents.
[0037] Conductive pillars 220 are arranged on both sides and in the middle of the bottom of the second liner 200, and the length of the conductive pillars 220 is less than the length of the spring 432 in the natural state. The conductive pillars 220 can not only play a conductive role, but also be used as limit pillars. After packaging, the conductive pillars 220 are supported between the first liner 100 and the second liner 200, so that the distance between the first liner 100 and the second liner 200 is guaranteed to compress the spring 432.
[0038] In one embodiment of the present application, there are a plurality of chips 110 arranged in a matrix on the first substrate 100, and each chip 110 is provided with a corresponding elastic connector 400. The chips 110 are arranged in two rows, and a plurality of signal pins 210 are arranged on the second substrate 200, and the signal pins 210 are arranged along the middle of the second substrate 200.
[0039] The driving signal is collected on the second backing plate 200, the driving path is arranged symmetrically, and the signal pin 210 is located in the middle of the left and right rows of chips 110. For example, the four signal pins 210 located directly above the chip 110 in the figure, the driving signal reaches the chip 110 in the same path, ensuring that the chip 110 is turned on and off at the same time. In addition, the driving path is short, reducing parasitic inductance and impedance. The position arrangement of the remaining signal pins 210 is adjusted according to the line arrangement on the second backing plate 200 to improve the signal reception strength.
[0040] During the unidirectional transmission of current on the first liner 100, the current is transmitted upward to the second liner 200 through the elastic layer and transmitted in the reverse direction to the power terminal 120. The stacked structure makes the current flow in the upper tube area produce an opposite flow effect. Compared with the single-layer liner planning, the stray inductance is lower.
[0041] In one embodiment of the present application, the production method of the double liner structure power module comprises the following steps:
[0042] Step 1: Install the chip 110 and the thermistor (NTC) on the first substrate 100 by welding, sintering or silver glue;
[0043] Step 2: Connect the signal pin 210, the conductive column 220 and the elastic connector 400 to the corresponding position of the second liner 200 by welding, silver sintering, copper sintering or ultrasonic welding;
[0044] Step 3: stack the second lining plate 200 with the elastic connector 400 to the corresponding position of the first lining plate 100, and complete the circuit connection; specifically:
[0045] The first liner plate 100 and the second liner plate 200 are connected by welding, and the DC AC terminal block is connected to the first liner plate 100;
[0046] The elastic connector 400 is connected to the source region of the chip 110 on the first substrate 100, and the conductive pillar 220 on the second substrate 200 is connected to the first substrate 100. The conductive pillar 220 not only conducts current upward and downward, but also acts as a limiter.
[0047] The length of the conductive column 220 is slightly shorter than the elastic connector 400, so that when the first liner 100 is connected to the second liner 200, the spring 432 is in a compressed state. Even if the distance between the chip 110 and the second liner 200 is greater than the theoretical value due to the warping of the two liner plates, the spring 432 can be compressed to compensate. When the distance between the chip 110 and the second liner 200 is less than the theoretical value, the spring 432 can be further compressed, thereby avoiding excessive stress caused by the rigid connection.
[0048] The compression of the spring 432 can exert force on the surface of the chip 110 , so that the spring 432 connection layer is stably connected to the chip 110 .
[0049] Step 4: Connect the binding wires 230, connect the first binding wire 230 to the gate of the chip 110, and connect the other end to the second substrate 200; connect the second binding wire 230 to the Kalvin source of the chip 110, and connect the other end to the second substrate 200, thereby completing the connection between the chip 110 and the second substrate 200;
[0050] The external driving signal is triggered by the driving board and reaches the gate of the chip 110 through the signal pin 210 and the binding wire 230 on the second substrate 200, flows out from the Kalvin source and then returns to the control board through the binding wire 230 and the signal pin 210, forming a complete driving circuit.
[0051] The NTC chip and the second lining plate 200 are also connected via other binding wires to form a temperature monitoring loop.
[0052] Step 5: The above components are encapsulated by transfer molding process to complete the production.
[0053] In this step, if the signal needle 210 is a split type, that is, only the needle seat is connected to the second liner 200 in the second step, after the transfer molding process is completed in this step, the signal needle 210 is inserted into the needle seat hole using the pin insertion method to complete the production.
[0054] In an electronic device in an embodiment of the present application, a power module therein adopts the double liner structure power module in any of the above embodiments, or a power module produced by the above production method.
[0055] According to one embodiment of the present application, the beneficial effects of adopting the double liner structure power module are:
[0056] The lower copper layer of the second liner is used for conduction instead of the area of the first liner, which improves the power density and reduces the overall size of the module.
[0057] The second liner is connected to the chip by an elastic connector, which absorbs the height difference between the first liner and the second liner due to deformation, and the spring pressure ensures that the lower connection copper layer is reliably connected to all chip sources;
[0058] All currents are collected on the lower copper layer of the second liner. The voltage balancing effect of the copper layer helps to balance the current of chips at different positions, thus improving the current output capacity of the module.
[0059] During module operation, after temperature cycling, since the second liner is not directly connected to the chip surface but flexibly connected through elastic connectors, the stress caused by the CTE mismatch between the two is greatly reduced, greatly improving the reliability life of the solder layer.
[0060] It should be noted that the above detailed descriptions are exemplary and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present application belongs.
[0061] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should also be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.
[0062] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein.
[0063] In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or inherent to these processes, methods, products, or apparatuses.
[0064] For ease of description, spatially relative terms, such as "above", "above", "on the upper surface of", "above", etc., may be used herein to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" may include both "above" and "below". The device may also be positioned in other different ways, such as rotated 90 degrees or in other orientations, and the spatially relative descriptions used herein are interpreted accordingly.
[0065] In the above detailed description, reference is made to the accompanying drawings, which form a part of this document. In the accompanying drawings, similar symbols typically identify similar components unless the context indicates otherwise. The illustrated embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be used, and other changes may be made, without departing from the spirit or scope of the subject matter presented herein.
[0066] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.
Claims
1. A double-liner structure power module, comprising a first liner, a chip disposed on the first liner, and a second liner stacked above the chip, wherein the first liner, the chip and the second liner are all plastic-sealed in a plastic package, characterized in that: An elastic connector is provided between the second liner and the chip. The elastic connector is made of conductive material, so that the source of the chip is electrically connected to the copper layer on the bottom surface of the second liner, and the gate of the chip is electrically connected to the copper layer on the top surface of the second liner through a binding wire.
2. The double liner structure power module according to claim 1, characterized in that: The elastic connecting member comprises an upper connecting copper layer, an elastic layer and a lower connecting copper layer. The upper connecting copper layer and the lower connecting copper layer are conductively connected. The elastic layer is at least used for elastic connection between the upper connecting copper layer and the lower connecting copper layer.
3. The double liner structure power module according to claim 2, characterized in that: The elastic layer is a corrugated copper plate, and the corrugated copper plate is electrically connected to the upper connection copper layer and the lower connection copper layer along a corrugation direction.
4. The double liner structure power module according to claim 3, characterized in that: The elastic layer further includes a spring, and the spring is supported between the upper connection copper layer and the lower connection copper layer.
5. The double liner structure power module according to claim 4, characterized in that: The spring always applies a downward pushing force to the lower connection copper layer.
6. The double liner structure power module according to claim 5, characterized in that: Conductive columns are arranged on both sides and in the middle of the bottom of the second lining plate, and the length of the conductive columns is smaller than the length of the spring in the natural state.
7. The double liner structure power module according to claim 4, characterized in that: The spring sleeve is arranged outside the corrugated copper plate.
8. The double liner structure power module according to claim 2, characterized in that: There are a plurality of chips arranged in a matrix on the first backing plate, and each chip is provided with a corresponding elastic connecting member.
9. The double liner structure power module according to claim 8, characterized in that: The chips are arranged in two rows, and a plurality of signal pins are arranged on the second backing plate, and the signal pins are arranged along the middle of the second backing plate.
10. An electronic device, characterized in that: A double liner structure power module according to any one of claims 1 to 9 is adopted.