Structure for preventing heat dissipation material from overflowing based on power semiconductor application

Abstract

The utility model discloses a structure for preventing a heat dissipation material from overflowing based on power semiconductor application. The structure comprises a power semiconductor module; the radiator is attached to the power semiconductor module and is used for radiating heat of the power semiconductor module; the heat dissipation material is arranged between the power semiconductor module and the heat sink and is used for conducting heat energy generated in the power semiconductor module to the heat sink; and the elastic sealing part is arranged between the power semiconductor module and the radiator by surrounding the periphery of the heat dissipation material so as to seal the heat dissipation material in a vacuum sealing cavity defined by the power semiconductor module, the radiator and the elastic sealing part and prevent the heat dissipation material from overflowing. The closed and vacuum structure of the utility model can ensure that the heat dissipation material stably exists between the power device and the radiator and does not overflow, thereby ensuring that the external thermal resistance of the device is stable and reliable in the whole life cycle, and ensuring the service life and safety of the device.

Description

Technical Field

[0001] This utility model relates to the field of power module technology, and specifically to a structure for preventing heat dissipation material overflow in power semiconductor applications. Background Technology

[0002] Power semiconductor devices, as the core of the electronics industry chain, enable power conversion and circuit control. To improve the power density of power semiconductor devices, they are typically bolted to heat sinks. This allows the self-heating of the power semiconductor device to be conducted to the heat sink through the heat dissipation material, and then transferred to the heat sink through other heat dissipation media via heat convection.

[0003] However, during installation (i.e., mounting onto a heat sink), the power semiconductor device generates heat, causing warping between the device interface and the heat sink interface due to factors such as mismatched coefficients of thermal expansion and stress constraints. This warping squeezes the heat dissipation material between the two interfaces, leading to material overflow. Over time, this overflow is often irreversible, resulting in air gaps between the power semiconductor device and the heat sink. This increases the thermal resistance compared to the initial stage of use, affecting heat dissipation and significantly reducing the device's lifespan and safety characteristics. Utility Model Content

[0004] The purpose of this invention is to address the problem that when power semiconductor devices are installed on heat sinks, heat dissipation material overflows, causing air gaps between the device and the heat sink, which increases thermal resistance and affects the lifespan and safety characteristics of the device. This invention designs a structure to prevent heat dissipation material overflow in power semiconductor applications, thereby solving the problem of heat dissipation material overflow and improving the application reliability of power semiconductor device products.

[0005] To achieve the above objectives, this utility model is implemented through the following technical solution:

[0006] This invention designs a structure for preventing heat dissipation material overflow in power semiconductor applications. The structure includes:

[0007] Power semiconductor modules;

[0008] A heat sink is attached to the power semiconductor module for heat dissipation of the power semiconductor module;

[0009] A heat dissipation material is disposed between the power semiconductor module and the heat sink to conduct heat generated in the power semiconductor module to the heat sink.

[0010] And an elastic sealing part, which is disposed between the power semiconductor module and the heat sink around the periphery of the heat dissipation material, so as to enclose the heat dissipation material in the vacuum sealing cavity formed by the power semiconductor module, the heat sink and the elastic sealing part, so as to prevent the heat dissipation material from overflowing.

[0011] Furthermore, a structure for preventing heat dissipation material overflow in power semiconductor applications: the power semiconductor module includes:

[0012] A plastic-encapsulated housing with several connection holes for connecting to the heat sink;

[0013] A metal-ceramic substrate having opposing welding surfaces and heat dissipation surfaces is disposed within the plastic encapsulation housing, with the heat dissipation surfaces exposed to the outside of the plastic encapsulation housing;

[0014] Several semiconductor chips are electrically connected to the welding surface of the metal-clad ceramic substrate (specifically, the semiconductor chips can be welded to the welding surface of the metal-clad ceramic substrate by reflow soldering or silver sintering).

[0015] A plurality of power terminals having opposing signal terminals and connection terminals, wherein the connection terminals are electrically connected to the welding surface of the metal-clad ceramic substrate, and the signal terminals extend to the outside of the plastic encapsulation shell (specifically, the connection terminals of the power terminals are welded to the welding surface of the metal-clad ceramic substrate by reflow soldering or ultrasonic pressing).

[0016] And several metal wires, one end of which is electrically connected to the semiconductor chip, and the other end of which is electrically connected to the surface of the metal-clad ceramic substrate or another semiconductor chip;

[0017] The welding surface of the metal-coated ceramic substrate and the surface of the semiconductor chip are completely covered with insulating material.

[0018] Furthermore, a structure for preventing heat dissipation material overflow in power semiconductor applications is provided: screws are connected in the connection hole and the heat sink to achieve a fixed connection between the plastic-encapsulated housing and the heat sink after they are attached.

[0019] Furthermore, a structure for preventing heat dissipation material overflow in power semiconductor applications is provided: an annular protrusion is also provided on the side of the plastic-encapsulated housing for attaching with the heat sink.

[0020] Furthermore, a structure for preventing heat dissipation material overflow in power semiconductor applications: the heat dissipation material is coated and disposed on the heat dissipation surface and / or the surface of the heat sink, and the heat dissipation material is located within the area enclosed by the annular protrusion.

[0021] Furthermore, a structure for preventing heat dissipation material overflow in power semiconductor applications: the elastic sealing part is configured as an annular structure, with one side in close contact with the heat sink and the other side forming an interference fit with the annular protrusion.

[0022] Furthermore, a structure for preventing heat dissipation material overflow in power semiconductor applications: the heat dissipation material is selected as thermal grease.

[0023] Furthermore, a structure for preventing heat dissipation material overflow in power semiconductor applications: the elastic sealing part is made of a material with a high content of elastic polymer matrix.

[0024] Furthermore, a structure for preventing heat dissipation material overflow in power semiconductor applications: the thickness of the elastic sealing portion is 50-100% of the thickness of the heat dissipation material.

[0025] Furthermore, a structure for preventing heat dissipation material overflow based on power semiconductor applications: In a vacuum environment, the installation between the power semiconductor module and the heat sink, heat dissipation material and elastic sealing part is completed to form a vacuum sealed cavity.

[0026] Specifically, this utility model designs a structure for preventing heat dissipation material overflow in power semiconductor applications. This involves a power semiconductor module, which includes a plastic-encapsulated shell with a defined through-hole (connection hole) to secure the device (power semiconductor module) to a heat sink. An elastic sealing portion is provided between the device and the heat sink to prevent heat dissipation material overflow. As the device heats up, the interface between the device and the heat sink warps due to factors such as mismatched coefficients of thermal expansion and stress constraints. This warps the heat dissipation material between the two interfaces, causing it to overflow. Prolonged overflow of heat dissipation material is often irreversible, creating an air gap between the power device and the heat sink. This increases thermal resistance, affecting heat dissipation, lifespan, and safety of the power device. Therefore, preventing heat dissipation material overflow is crucial. However, existing power device application structures have not addressed this issue, resulting in reduced safety and lifespan of the power semiconductor module after installation on the heat sink. This application identifies this problem leading to reduced safety and lifespan of power semiconductor modules and proposes a corresponding solution, thereby improving the application reliability of power semiconductor module products.

[0027] The beneficial effects of this utility model are:

[0028] (1) Differences in physical structure can affect the effect of preventing heat dissipation material from overflowing. Therefore, in the structure designed in this utility model for preventing heat dissipation material from overflowing based on power semiconductor applications, an interference fit structure design is preferred, which has a better effect of preventing heat dissipation material from overflowing. The elastic sealing part can limit the interface between the heat sink and the plastic shell. The preferred elastic sealing part is not limited to a specific shape, but it is better to extend along the annular protrusion surface of the shell to form a closed loop. The annular elastic sealing part can also provide the following advantages: the annular protrusion on the plastic shell helps to improve the positioning deviation during installation.

[0029] (2) The choice of material for the elastic sealing part also affects the effect of preventing heat dissipation material from overflowing. The present invention preferably uses a filler with a high polymer matrix content, which can strongly suppress the overflow of heat dissipation material. Preferredly, given that the processing precision of the plastic-encapsulated shell and the heat sink is relatively low, the surface roughness will cause small gaps. The sealing part with sufficient elasticity and softness has a better sealing effect with the power semiconductor device and the heat sink surface under compression, thereby further improving the effect of preventing heat dissipation material from overflowing.

[0030] (3) When installing power semiconductor devices, the residual air in the gap between the elastic sealing part and the heat dissipation material will continuously impact the sealing effect during the temperature cycle, thereby damaging the sealing effect, causing the heat dissipation material to overflow, and ultimately resulting in poor heat dissipation effect and affecting the service life of the device. The present invention prefers to install the device in a vacuum environment, which will effectively remove the air in the internal gap and avoid the above problems.

[0031] (4) The heat dissipation material is placed between the copper-clad ceramic substrate and the heat sink of the device. An elastic sealing part of appropriate thickness helps to relieve the stress on the copper-clad ceramic substrate during installation, thereby improving the safety of the device application. However, an elastic sealing part that is too thin cannot completely seal the device, while an elastic sealing part that is too thick will affect the heat dissipation effect of the device. The preferred thickness of the elastic sealing part in this invention is controlled to be 50-100% of the thickness of the heat dissipation material, which ensures both the sealing effect and the heat dissipation effect.

[0032] (5) The structure designed in this utility model can ensure that all electrical, thermal and mechanical parameters of the power semiconductor device remain unchanged. No matter what tooling environment the device is used in, it will not overflow due to the change of the state of the heat dissipation material at the temperature. The sealed and vacuum structure of this utility model can ensure that the heat dissipation material exists stably between the power device and the heat sink without overflowing, thereby ensuring that the external thermal resistance of the device is stable and reliable throughout its entire life cycle, and guaranteeing its service life and safety. Attached Figure Description

[0033] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments 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.

[0034] Figure 1 This is a schematic diagram of a structure designed for preventing heat dissipation material overflow in power semiconductor applications.

[0035] The markings in the diagram are: 1-Power semiconductor module, 2-Heat sink, 3-Heat dissipation material, 4-Elastic sealing part, 5-Vacuum sealing cavity, 6-Screw, 11-Plastic encapsulation shell, 12-Metal-coated ceramic substrate, 13-Semiconductor chip, 14-Power terminal, 15-Metal wire, 111-Connection hole, 112-Annular protrusion. Detailed Implementation

[0036] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present utility model or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of the present utility model without creative effort are within the scope of protection of the present utility model.

[0037] In the description of this utility model, it should be understood that the terms "upper," "lower," "left," "right," "top," and "bottom," etc., indicating orientation or positional relationships, are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "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 indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include one or more of that feature. Moreover, the terms "first," "second," etc., are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that embodiments of this utility model described herein can be implemented in orders other than those illustrated or described herein.

[0038] Example 1

[0039] like Figure 1As shown, this embodiment 1 designs a structure to prevent heat dissipation material overflow in power semiconductor applications. The structure includes:

[0040] Power semiconductor module 1;

[0041] Heat sink 2 is attached to the power semiconductor module 1 for heat dissipation of the power semiconductor module 1;

[0042] A heat dissipation material (selected as thermal grease) 3 is disposed between the power semiconductor module 1 and the heat sink 2 to conduct the self-heating generated by the power semiconductor module 1 during operation to the heat sink 2.

[0043] And an elastic sealing part (using a filler with a high polymer matrix content) 4, which is disposed around the periphery of the heat dissipation material 3 between the power semiconductor module 1 and the heat sink 2, so as to enclose the heat dissipation material 3 in the vacuum sealing cavity 5 formed by the power semiconductor module 1, the heat sink 2 and the elastic sealing part 4, thereby preventing the heat dissipation material 3 from overflowing; the thickness of the elastic sealing part 4 is set to 50-100% of the thickness of the heat dissipation material 3;

[0044] The installation of the power semiconductor module 1, heat sink 2, heat dissipation material 3, and elastic sealing part 4 described above is carried out in a vacuum environment;

[0045] The power semiconductor module 1 includes:

[0046] The plastic-encapsulated housing 11 has several connection holes 111 for connecting to the heat sink 2. By connecting screws 6 in the connection holes 111 and the heat sink 2, the plastic-encapsulated housing 11 can be attached to the heat sink 2 for connection and fixation. The plastic-encapsulated housing 11 also has an annular protrusion 112, which is located on the side of the plastic-encapsulated housing 11 for attaching to the heat sink 2.

[0047] A metal-clad ceramic substrate (DBC) 12 has opposing welding surfaces and a heat dissipation surface. The metal-clad ceramic substrate 12 is disposed in the plastic encapsulation housing 11, and the heat dissipation surface is exposed to the outside of the plastic encapsulation housing 11. The heat dissipation material 3 is coated on the heat dissipation surface or the surface of the heat sink 2, and the heat dissipation material 3 is located within the area enclosed by the annular protrusion 112. The elastic sealing part 4 is configured as an annular structure, with one side in close contact with the heat sink 2 and the other side forming an interference fit with the annular protrusion 112.

[0048] A plurality of semiconductor chips 13 are electrically connected to the welding surface of the metal-clad ceramic substrate 12;

[0049] A plurality of power terminals 14 having signal terminals and connection terminals, wherein the connection terminals are electrically connected to the welding surface of the metal-clad ceramic substrate 12, and the signal terminals extend to the outside of the plastic encapsulation housing 11.

[0050] And a number of metal lines 15, one end of which is electrically connected to the semiconductor chip 13, and the other end is electrically connected to the surface of the metal-ceramic substrate 12 or another semiconductor chip 13.

[0051] The welding surface of the metal-clad ceramic substrate 12 and the surface of the semiconductor chip 13 are completely covered with insulating material.

[0052] Specifically, in this example 1, thermal grease 3 is evenly applied to the power semiconductor module 1 or heat sink 3 in advance. The annular elastic sealing part 4 is placed in advance according to the installation position of the power semiconductor module 1 so that it forms an interference fit with the annular protrusion 112 on the plastic shell 11. Then, the plastic shell 11 is locked to the heat sink 2 with screws 6.

[0053] The annular elastic seal 4 extends along the annular protrusion 112 surface of the plastic housing 11 to form a better closed loop effect. The annular seal 4 can also provide the following advantages: the annular protrusion 112 on the housing helps to improve the positioning deviation when the power semiconductor module 1 is installed.

[0054] Because the residual air in the gap between the elastic sealing part 4 and the thermal grease 3 will continuously impact the sealing effect during temperature cycling, the cavity 5 formed between the sealing part 4 and the thermal grease 3 will be affected by the environment during installation. Therefore, installing the device in a vacuum environment will effectively remove the air in the internal gap.

[0055] Specifically, during the installation and application of the power semiconductor device 1 onto the heat sink 2, the self-heating generated by the power semiconductor device 1 during operation causes warping changes at the interfaces of device 1 and heat sink 2 due to factors such as mismatch in thermal expansion coefficients and stress constraints. This warping squeezes the heat dissipation material 3 between the two interfaces, causing it to overflow. Over time, the overflow of heat dissipation material 3 is often irreversible, resulting in an air gap between the power semiconductor device 1 and the heat sink 2. This leads to a greater thermal resistance than in the initial stage of use, affecting the heat dissipation of device 1 and significantly reducing its lifespan and safety characteristics. Therefore, preventing the overflow of heat dissipation material 3 is particularly important. However, the problem that air gaps easily form after power semiconductor devices 1 are installed on heat sinks 2, leading to increased thermal resistance and affecting the heat dissipation, lifespan, and safety characteristics of devices 1, has not received much attention. This invention addresses this issue that reduces the safety and lifespan of power semiconductor modules 1 after application and designs a structure to prevent heat dissipation material overflow in power semiconductor applications. This solves many negative problems caused by overflow, improves the application reliability of power semiconductor modules, ensures that no air gaps appear between the heat dissipation material 3 and the power semiconductor module 1 and heat sink 2 throughout the entire lifespan of the power semiconductor module 1, ensures stable and reliable external thermal resistance, and guarantees its lifespan and safety.

[0056] The above-described preferred embodiments of this utility model are for illustrative purposes only and are not intended to limit the scope of this utility model. Any obvious variations or modifications derived from the technical solutions of this utility model are still within the protection scope of this utility model.

Claims

1. A structure for preventing heat dissipation material overflow in power semiconductor applications, characterized in that, The structure includes: Power semiconductor module (1); A heat sink (2) is attached to the power semiconductor module (1) for dissipating heat from the power semiconductor module (1); Heat dissipation material (3) is disposed between the power semiconductor module (1) and the heat sink (2) to conduct the heat generated in the power semiconductor module (1) to the heat sink (2); And an elastic sealing part (4), which is disposed between the power semiconductor module (1) and the heat sink (2) around the periphery of the heat dissipation material (3) to enclose the heat dissipation material (3) in the vacuum sealed cavity (5) formed by the power semiconductor module (1), the heat sink (2) and the elastic sealing part (4) to prevent it from overflowing.

2. The structure for preventing heat dissipation material overflow in power semiconductor applications according to claim 1, characterized in that, The power semiconductor module (1) includes: A plastic-encapsulated housing (11) is provided with a plurality of connection holes (111) for connecting to the heat sink (2); A metal-ceramic substrate (12) having opposing welding surfaces and heat dissipation surfaces is disposed in the plastic encapsulation housing (11), and the heat dissipation surfaces are exposed to the outside of the plastic encapsulation housing (11); Several semiconductor chips (13) are electrically connected to the welding surface of the metal-clad ceramic substrate (12); A plurality of power terminals (14) having signal terminals and connection terminals, the connection terminals being electrically connected to the welding surface of the metal-clad ceramic substrate (12), and the signal terminals extending to the outside of the plastic encapsulation housing (11). And a number of metal lines (15), one end of which is electrically connected to the semiconductor chip (13) and the other end is electrically connected to the surface of the metal-clad ceramic substrate (12) or another semiconductor chip (13); The welding surface of the metal-clad ceramic substrate (12) and the surface of the semiconductor chip (13) are completely covered with insulating material.

3. The structure for preventing heat dissipation material overflow in power semiconductor applications according to claim 2, characterized in that, By connecting screws (6) in the connection hole (111) and the heat sink (2), the plastic-encapsulated housing (11) is fixedly connected to the heat sink (2) after being attached.

4. The structure for preventing heat dissipation material overflow in power semiconductor applications according to claim 2, characterized in that, The plastic-encapsulated housing (11) is also provided with an annular protrusion (112) on the side for fitting with the heat sink (2).

5. The structure for preventing heat dissipation material overflow in power semiconductor applications according to claim 4, characterized in that, The heat dissipation material (3) is coated on the surface of the heat dissipation surface and / or the surface of the heat sink (2), and the heat dissipation material (3) is located within the area enclosed by the annular protrusion (112).

6. The structure for preventing heat dissipation material overflow in power semiconductor applications according to claim 4, characterized in that, The elastic sealing part (4) is configured as an annular structure, with one side in close contact with the radiator (2) and the other side forming an interference fit with the annular protrusion (112).

7. The structure for preventing heat dissipation material overflow in power semiconductor applications according to claim 1, characterized in that, The heat dissipation material (3) is selected as thermally conductive silicone grease.

8. The structure for preventing heat dissipation material overflow in power semiconductor applications according to claim 1, characterized in that, The elastic sealing part (4) is made of a material with a high polymer matrix content.

9. The structure for preventing heat dissipation material overflow in power semiconductor applications according to claim 1, characterized in that, The thickness of the elastic sealing part (4) is 50 to 100% of the thickness of the heat dissipation material (3).

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