A heat-conducting silicone grease application tool and an IGBT module mounting method using the same

Abstract

This invention provides a thermal grease application tool and an IGBT module installation method using the tool, relating to the field of semiconductor device technology. The thermal grease application tool includes a base, with at least one grease conduit on one side of the base for holding thermal grease. The end of the grease conduit away from the base is open, and the grease conduit corresponds to the location on the IGBT module where thermal grease needs to be applied. An IGBT module installation method using the aforementioned thermal grease application tool is also provided. Based on the technical solution of this invention, thermal grease is applied to the actual required location on the IGBT module, facilitating control of the amount of thermal grease used, maximizing the direct connection area between the IGBT module and the heatsink, effectively reducing thermal resistance, improving the heat dissipation effect of the heatsink on the IGBT module, and extending the service life of the IGBT module.

Description

Technical Field

[0001] This invention relates to the field of semiconductor device technology, and in particular to a thermal grease application tool and an IGBT module installation method using the tool. Background Technology

[0002] IGBT modules are composite, fully controllable, voltage-driven functional semiconductor devices composed of bipolar junction transistors (BJTs) and insulated-gate field-effect transistors (IGFETs). They are widely used in rail transportation, smart grids, aerospace, electric vehicles, and new energy equipment. During normal operation, IGBT modules are typically equipped with heat sinks for cooling. To ensure optimal connection between the IGBT module and the heat sink and maintain low thermal resistance, direct contact between the module and the heat sink should be maximized. However, in reality, because the substrate of the IGBT module and the surface of the heat sink are not perfectly level, gaps exist, and these gaps exhibit significant thermal resistance. To reduce this thermal resistance, a material with lower thermal resistance than air is needed to fill these gaps—thermal grease.

[0003] Thermal grease, as a material that aids in heat dissipation, plays a crucial role in cooling IGBT modules. While thermal grease does reduce thermal resistance compared to air, it is still far less effective than direct contact. Therefore, only an appropriate amount of thermal grease can truly reduce thermal resistance; too much or too little grease will increase thermal resistance and hinder heat dissipation.

[0004] Currently, thermal grease is typically applied to IGBT modules using a scraper or roller. However, this method often results in uneven distribution of the grease on the IGBT module, with some grease extruding from the edges of the substrate. This leads to suboptimal thermal resistance between the IGBT module and the heatsink, negatively impacting the IGBT module's heat dissipation performance. Summary of the Invention

[0005] This invention provides a thermal grease application tool and an IGBT module installation method using the tool, which solves the problem of uneven thermal grease application on IGBT modules, minimizes the thermal resistance between the IGBT module and the heat sink, improves the heat dissipation effect of the IGBT module, and extends the service life of the IGBT module.

[0006] The present invention provides a thermal grease application tool, including a base, wherein at least one grease conduit is provided on one side of the base for containing thermal grease, the end of the grease conduit away from the base is open, and the grease conduit corresponds to the position on the IGBT module where thermal grease needs to be applied.

[0007] In one embodiment, the base is made of an elastic material.

[0008] In one embodiment, a through hole is provided on the base corresponding to the screw hole position on the IGBT module.

[0009] This embodiment effectively avoids the screw holes on the IGBT module and the corresponding heat sink when applying thermal grease, preventing the thermal grease from clogging the screw holes and ensuring the screw installation torque.

[0010] In one embodiment, the silicone grease conduit includes silicone grease type I conduits and silicone grease type II conduits with different inner diameters.

[0011] In this embodiment, thermal grease conduits of different inner diameters correspond to different application areas. Larger inner diameter conduits are used for areas on the IGBT module substrate with relatively rough surfaces and insufficient surface smoothness, while smaller inner diameter conduits are used for areas with less surface roughness and smoothness. Thus, by using thermal grease conduits of different inner diameters, the size and thickness of the thermal grease applied to different locations on the IGBT module substrate can be effectively controlled, preventing excessive thickness of thermal grease in localized areas and ensuring the heat dissipation effect of the IGBT module.

[0012] In one embodiment, the inner diameter of the silicone grease type I catheter is 0.05–0.5 mm, and the inner diameter of the silicone grease type II catheter is 0.1–1 mm.

[0013] In one embodiment, the silicone grease conduit is arranged perpendicularly to the base, and the silicone grease conduit is detachably connected to the base.

[0014] This implementation method allows operators to easily adjust the position of the thermal grease conduit, facilitating control over the application location and thickness of the thermal grease.

[0015] In one embodiment, the silicone grease conduit is made of iron, aluminum, or an alloy.

[0016] In one embodiment, the inner diameter of the silicone grease type II conduit is larger than that of the silicone grease type I conduit, and the position of the silicone grease type II conduit on the base corresponds to the area on the IGBT module that experiences severe heat generation.

[0017] In this embodiment, the areas on the IGBT module that generate severe heat are usually the areas with insufficient heat dissipation, that is, the areas with large surface roughness and flatness on the substrate. Therefore, by applying the type II silicone grease conduit to these areas, the heat dissipation effect in these areas can be improved.

[0018] Another aspect of the present invention provides an IGBT module installation method using the above-mentioned thermal grease application tool, comprising the following steps:

[0019] S1. Check the IGBT module and its corresponding heat sink;

[0020] S2. Apply a layer of thermal grease to the IGBT module using a thermal grease applicator.

[0021] S3. Install the IGBT module onto the corresponding heatsink.

[0022] In one embodiment, the surface roughness of the heat sink used for mounting the IGBT module is at most 10 μm, and its surface flatness is at most 50 μm.

[0023] By controlling the roughness and flatness of the surface of the heat sink used to mount the IGBT module, this embodiment helps to improve the heat dissipation effect of the heat sink on the IGBT module.

[0024] In one implementation, step S2 includes the following sub-steps:

[0025] S2.1. Based on the surface roughness, surface flatness, and contact area of ​​the IGBT module and heat sink, select the appropriate type of thermal grease conduit, determine the number of thermal grease conduits, and adjust the installation position of the thermal grease conduits on the base.

[0026] S2.2 Inject thermally conductive silicone grease into the silicone grease conduit;

[0027] S2.3 Place the application tool directly above the IGBT module substrate, with one end of the silicone grease conduit opening facing down and in contact with the IGBT module substrate;

[0028] S2.4. Gently press the side of the base away from the grease conduit and slowly lift the base to squeeze the thermal grease out of the grease conduit and apply it to the IGBT module substrate.

[0029] In one embodiment, in step S2.1, the silicone grease conduit with a larger inner diameter corresponds to the location on the IGBT module with greater surface roughness and surface flatness, while the silicone grease conduit with a smaller inner diameter corresponds to the location on the IGBT module with less surface roughness and surface flatness.

[0030] In one embodiment, in step S2, the thickness of the thermal grease application is 50–100 μm.

[0031] In summary, compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0032] (1) Applying thermal grease to the designated location on the IGBT module using the grease conduit can effectively control the application location and thickness of the thermal grease, effectively reduce the thermal resistance between the IGBT module and the heat sink, improve the heat dissipation effect of the heat sink on the IGBT module, and extend the service life of the IGBT module.

[0033] (2) Apply thermal grease to different locations on the IGBT module using grease conduits with different inner diameters. Apply the thermal grease to the areas where the IGBT module actually needs it. This makes it easier to control the amount and uniformity of the thermal grease application and ensures that the direct connection area between the IGBT module and the heat sink is maximized. This effectively reduces thermal resistance and ensures the heat sink's heat dissipation effect on the IGBT module. Attached Figure Description

[0034] The invention will now be described in more detail with reference to embodiments and the accompanying drawings.

[0035] Figure 1 This is a top view of a thermal grease application tool according to one embodiment of the present invention;

[0036] Figure 2 This is a bottom view of a thermal grease application tool according to one embodiment of the present invention;

[0037] Figure 3 This is a flowchart illustrating an IGBT module installation method according to one embodiment of the present invention.

[0038] Reference numerals: 1. Base; 2. Through hole; 3. Silicone grease conduit; 31. Silicone grease type I conduit; 32. Silicone grease type II conduit. Detailed Implementation

[0039] The present invention will now be described clearly and completely with reference to the accompanying drawings.

[0040] See appendix Figure 1-2 A thermal grease application tool includes a base 1 and a grease conduit 3 disposed on one side of the base 1. The grease conduit 3 is hollow inside, with an opening at the end furthest from the base 1, and can hold thermal grease. In actual operation, thermal grease is injected into the grease conduit 3, the base 1 is positioned directly opposite the IGBT module, and the opening of the grease conduit 3 faces downwards and contacts the IGBT module substrate. After the base 1 is slowly lifted, the thermal grease in the grease conduit 3 will be discharged from its opening end and applied to the IGBT module.

[0041] In this embodiment, the base 1 can be made of metal or non-metallic elastic material, but to facilitate the discharge of thermal grease, it is preferably made of elastic material such as plastic or sponge. The shape of the base 1 can be flexibly designed as needed, such as being circular, rectangular, or other shapes, without specific limitations. Similarly, the size of the base 1 can also be flexibly adjusted according to usage requirements, but to ensure that all areas on the IGBT module that need to be coated with thermal grease can be coated, the area of ​​the side of the base 1 used to install the thermal grease conduit 3 should not be less than the area of ​​the surface of the IGBT module to which the thermal grease is to be applied.

[0042] In another embodiment, considering that the IGBT module and the corresponding heat sink are provided with screw holes for connection, to avoid thermal grease clogging the screw holes, the base 1 is provided with through holes 2 at the corresponding screw hole positions. Specifically, the number and position of the through holes 2 can be determined according to the number and position of the screw holes on the IGBT module and the heat sink, and the diameter of the through holes 2 should not be less than the diameter of the corresponding screw holes.

[0043] In this embodiment, the material of the aforementioned thermal grease conduit 3 can be metal or non-metal, but to ensure the convenience and accuracy of thermal grease application, it is preferably made of iron, aluminum, or an alloy, without specific limitations. When actually installing the thermal grease conduit 3, it is preferably detachably connected to the base 1 to facilitate subsequent adjustment of its position so that it is aligned with the area on the IGBT module where thermal grease needs to be applied. Specifically, if the base 1 is made of metal, the thermal grease conduit 3 can be threaded to the base 1; if the base 1 is made of non-metallic materials such as plastic or sponge, the thermal grease conduit 3 can be glued to the base 1. Furthermore, to facilitate alignment of the thermal grease conduit 3 with the area on the IGBT module where thermal grease needs to be applied, the thermal grease conduit 3 is preferably vertically positioned on the base 1.

[0044] When actually installing an IGBT module onto a heatsink, the area where the IGBT module and the corresponding heatsink can directly contact each other has relatively low thermal resistance and does not require the application of thermal grease. However, the areas where gaps appear due to surface roughness and flatness have higher thermal resistance and are the areas that generate significant heat during operation; these are the areas where thermal grease should be applied. Considering this, the number of grease conduits 3 on the base 1 can be determined based on the area where thermal grease needs to be applied, and their placement on the base 1 can be determined based on the location of that area. Therefore, multiple grease conduits 3 are typically installed on the base 1, and the specific number is not limited.

[0045] In another embodiment, to further improve the rationality of the amount of thermal grease applied, the aforementioned grease conduit 3 can be designed in various different models according to its inner diameter. The inner diameter of the grease conduit 3 can be determined based on the surface roughness and surface flatness of the corresponding position on the IGBT module; in practical applications, the grease conduit 3 with a larger inner diameter corresponds to the area on the IGBT module with higher thermal resistance and more severe heat generation, while the grease conduit 3 with a smaller inner diameter corresponds to the area on the IGBT module with lower thermal resistance and relatively less heat generation. For example, the type of silicone grease conduit 3 may include silicone grease type I conduit 31 and silicone grease type II conduit 32. The inner diameter of silicone grease type I conduit 31 is 0.05-0.5 mm, and the inner diameter of silicone grease type II conduit 32 is 0.1-1 mm. When the inner diameter of silicone grease type I conduit 31 is 0.5 mm and the inner diameter of silicone grease type II conduit is 1 mm, the inner diameter of silicone grease type II conduit 32 is larger than that of silicone grease type I conduit 31. Therefore, silicone grease type II conduit 32 will correspond to the area with higher thermal resistance between the IGBT module and the heat sink, while silicone grease type I conduit 31 will correspond to the area with lower thermal resistance between the IGBT module and the heat sink.

[0046] As described above, the thermal grease application tool provided in this embodiment is mainly used for applying thermal grease to IGBT modules. However, it should be noted that, based on the description of this embodiment, those skilled in the art can easily apply it to the application of other materials (such as adhesives). Therefore, without any creative effort, applying the application tool disclosed in this embodiment to other similar situations does not exceed the protection scope of this invention.

[0047] See appendix Figure 3 The present invention also provides an IGBT module installation method using the above-mentioned thermal grease application tool, comprising the following steps:

[0048] S1. Check the IGBT module and its corresponding heat sink.

[0049] Specifically, when inspecting IGBT modules and their corresponding heat sinks, the heat sink should be selected and matched according to the usage conditions, environment, and parameters of the corresponding IGBT module to ensure that the IGBT module can work normally. Heat sinks with excessively rough mounting surfaces should not be selected; the roughness of the mounting surface should not exceed 10μm, and its surface flatness should not exceed 50μm.

[0050] Under the premise of meeting the above conditions, the surface roughness, surface flatness, and contact area between the IGBT module substrate and the heat sink should also be tested and determined in order to determine which areas on the IGBT module can directly contact the heat sink mounting surface, which areas have gaps and large thermal resistance, and thus determine which positions on the IGBT module actually need to be coated with thermal grease and the theoretical thickness of thermal grease that should be applied to the corresponding areas.

[0051] S2. Apply a layer of thermal grease to the IGBT module using a thermal grease applicator.

[0052] Specifically, when applying thermal grease to the IGBT module using the aforementioned thermal grease application tool, the following steps can be followed:

[0053] S2.1. Based on the surface roughness, surface flatness and contact area of ​​the IGBT module and the heat sink, select the appropriate type of thermal grease conduit 3, determine the number of thermal grease conduits 3 and adjust the installation position of the thermal grease conduits 3 on the base 1.

[0054] S2.2 Inject thermally conductive silicone grease into the silicone grease conduit 3;

[0055] S2.3 Place the application tool directly above the IGBT module substrate, with one end of the silicone grease conduit 3 facing downwards and in contact with the IGBT module substrate.

[0056] S2.4. Gently press the side of the base 1 away from the silicone grease conduit 3, and slowly lift the base 1 to squeeze the thermal grease out of the silicone grease conduit 3 and apply it to the IGBT module substrate.

[0057] After determining the areas on the IGBT module substrate that require thermal grease application and the corresponding thickness of thermal grease, specific types of thermal grease conduits 3 can be selected and their quantities determined. These conduits 3 are then installed on the corresponding positions on the base 1. During the actual application process, the larger-diameter conduits 3 correspond to areas with higher surface roughness and flatness on the IGBT module, while the smaller-diameter conduits 3 correspond to areas with lower surface roughness and flatness. Each conduit 3 can be accurately aligned with the designated areas on the IGBT module, facilitating control of the amount and uniformity of thermal grease application.

[0058] Meanwhile, after applying the thermal grease, the base 1 should not be pressed too hard to avoid the grease conduit 3 violently impacting the IGBT module substrate and causing damage. When lifting the base 1, it should also be lifted slowly to avoid the thermal grease not being applied to the IGBT substrate in time and sufficiently.

[0059] After the actual application, the thickness of the thermal grease on the IGBT module substrate is generally 50-100μm. This avoids the thermal grease being applied too thinly, which would result in a gap between the IGBT module and the heat sink, and also avoids the thermal grease being applied too thickly, which would increase the thermal resistance between the IGBT module and the heat sink and hinder efficient heat dissipation.

[0060] S3. Install the IGBT module onto the corresponding heatsink.

[0061] When installing IGBT modules, the installation method should be determined based on the type of IGBT module substrate. When the IGBT module substrate is a copper plate, after placing the IGBT module on the heatsink mounting surface, apply pressure evenly to the IGBT module; ideally, a small amount of thermal grease should be visible oozing from the edges of the IGBT module. When the IGBT module substrate is a DBC substrate, the heatsink mounting surface must be flat and smooth. After placing the IGBT module on the heatsink, apply pressure evenly to the IGBT module.

[0062] Simultaneously, when securing the IGBT module to the heatsink, all screws must be tightened to the torque specified in the instruction manual. Insufficient torque will increase thermal resistance between the two or cause the screws to loosen during movement. When installing only one IGBT module on the heatsink, the IGBT module is preferably installed in the center of the heatsink mounting surface to minimize thermal resistance. When multiple IGBT modules need to be installed, the spacing between each IGBT module should be controlled according to the heat generation of each IGBT module; more space should be reserved between IGBT modules that generate more heat and adjacent IGBT modules.

[0063] When installing screws at two points, first tighten each screw to 1 / 3 of its rated torque, then repeat several times until the rated torque is reached. Four-point installation is similar to two-point installation, so I won't elaborate further.

[0064] Furthermore, if using a heatsink with a textured mounting surface, the length of the IGBT module should follow the texture of the heatsink to reduce heatsink deformation. If multiple IGBT modules are installed, they should be placed side-by-side along their width, with sufficient distance between adjacent modules to reduce heat accumulation, facilitate heat dissipation, maximize heatsink efficiency, and facilitate IGBT module terminal connections, reducing stray inductance, which is especially important when IGBT modules are used at high frequencies.

[0065] In the description of this invention, it should be understood that the terms "upper", "lower", "bottom", "top", "front", "rear", "inner", "outer", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention 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. Therefore, they should not be construed as limitations on this invention.

[0066] Although the invention has been described with reference to preferred embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, the technical features mentioned in the various embodiments can be combined in any manner as long as there is no structural conflict. The invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. An IGBT module mounting method using a heat-conductive silicone grease application tool, the heat-conductive silicone grease application tool comprising a base, at least one silicone grease conduit for containing heat-conductive silicone grease being arranged on one side of the base, an opening being arranged at a distal end of the silicone grease conduit away from the base, and the silicone grease conduit corresponding to a position on the IGBT module where the heat-conductive silicone grease needs to be applied; the silicone grease conduit comprising a silicone grease I-type conduit and a silicone grease II-type conduit, the inner diameter of the silicone grease II-type conduit being greater than the inner diameter of the silicone grease I-type conduit, and the silicone grease I-type conduit being distributed around the silicone grease II-type conduit; the mounting method comprising the following steps: S1, checking the IGBT module and the corresponding heat sink; S2, applying a layer of heat-conductive silicone grease on the IGBT module using the heat-conductive silicone grease application tool; step S2 comprising the following sub-steps: S2.1, selecting a suitable type of silicone grease conduit according to the surface roughness, surface flatness and contact area of the IGBT module and the heat sink, determining the number of silicone grease conduits and adjusting the installation position of the silicone grease conduit on the base; wherein the silicone grease conduit with a larger inner diameter corresponds to a position on the IGBT module with a larger surface roughness and surface flatness, and the silicone grease conduit with a smaller inner diameter corresponds to a position on the IGBT module with a smaller surface roughness and surface flatness; S2.2, injecting heat-conductive silicone grease into the silicone grease conduit; S2.3, placing the application tool directly above the IGBT module substrate, with the opening end of the silicone grease conduit facing downward and contacting the IGBT module substrate; S2.4, pressing the side of the base away from the silicone grease conduit, and slowly lifting the base to extrude the heat-conductive silicone grease from the silicone grease conduit and apply it on the IGBT module substrate; the thickness of the applied heat-conductive silicone grease being 50-100 μm; S3, mounting the IGBT module on the corresponding heat sink.

2. The method of claim 1, wherein, The base is made of an elastic material.

3. The IGBT module mounting method according to claim 1 or 2, characterized by, A through hole is arranged on the base corresponding to the screw hole position on the IGBT module.

4. The method of claim 1, wherein, The inner diameter of the silicone grease I-type conduit is 0.05-0.5 mm, and the inner diameter of the silicone grease II-type conduit is 0.1-1 mm.

5. The method of mounting an IGBT module according to claim 1 or 4, wherein The silicone grease conduit is arranged vertically with the base, and the silicone grease conduit and the base are detachably connected.

6. The method of mounting an IGBT module according to claim 1 or 4, wherein The silicone grease conduit is made of iron, aluminum or alloy material.

7. The method of mounting an IGBT module according to claim 1 or 4, wherein The position of the silicone grease II-type conduit on the base corresponds to the area on the IGBT module where the heat is most serious.

8. The method of claim 1, wherein, The surface roughness of the surface of the heat sink for mounting the IGBT module is at most 10 μm, and the surface flatness is at most 50 μm.

Images