Fixed structure of power semiconductor device, and heat sink and frequency conversion device

Abstract

The utility model relates to the technical field of electronic product discloses the fixed structure, and radiator and frequency conversion device of power semiconductor device, the fixed structure of power semiconductor device includes: the heat dissipation main body, first insulating heat conducting layer and second insulating heat conducting layer, form a number of second area on the second insulating heat conducting layer the thickness is lower than the first area, the thickness of second area is less than the thickness of first area, and the thickness difference of first area and second area is set to the thickness 2.5 5 times of second area, can make the dielectric breakdown voltage, withstand torque and junction - water thermal resistance etc. Performance requirements of second area reach optimal combination, thereby making the fixed stability of power semiconductor device higher, not easy to fall off in the use process, has promoted the withstand torque performance of power semiconductor device, thereby making the finished product yield of final power semiconductor device improve.

Description

Technical Field

[0001] This utility model relates to the field of electronic product technology, specifically to the fixed structure of power semiconductor devices, as well as heat sinks and frequency converters. Background Technology

[0002] In related technologies, power devices generate significant heat during operation, typically requiring external heat sinks for heat conduction and dissipation to ensure stable temperature operation and prevent overheating damage. Because power devices have inherent electrical insulation requirements, a thermally conductive and insulating intermediate structure is usually needed between the device and the heat sink to balance heat transfer efficiency and electrical safety.

[0003] Common thermally conductive and insulating structures include: placing a ceramic substrate on the metal shell surface of the heat sink and coating it with silicone grease, or attaching a thermally conductive insulating film to the metal shell surface of the heat sink, in order to achieve the functions of heat conduction and electrical isolation. Existing technologies also include fixing power devices by spraying a resin thermally conductive insulating layer.

[0004] In the existing technology, after the thermal insulation structure of power devices is fixed, there is a technical problem that the defect rate of finished products increases. Therefore, the existing technology has defects and needs to be improved. Utility Model Content

[0005] In view of this, the present invention provides a fixing structure for power semiconductor devices, as well as a heat sink and a frequency converter, to solve the technical problem of increased defect rate of high voltage power devices after fixing in the prior art.

[0006] To solve the above-mentioned technical problems, the technical solution of this utility model is as follows:

[0007] In a first aspect, this utility model provides a fixing structure for a power semiconductor device, comprising: a heat dissipation body, a first insulating thermally conductive layer, and a second insulating thermally conductive layer, wherein the first insulating thermally conductive layer is laid on the heat dissipation body; the second insulating thermally conductive layer is laid on the first insulating thermally conductive layer and is used to adhere and fix the power semiconductor device; the second insulating thermally conductive layer has a first region and a plurality of second regions, wherein the power semiconductor device is adhered and fixed in the second region; wherein the thickness of the second region is less than the thickness of the first region, and the thickness difference between the first region and the second region is set to 2.5-5 times the thickness of the second region.

[0008] It has the following advantages:

[0009] The power semiconductor device fixing structure provided by this utility model consists of a first insulating and thermally conductive layer laid on a heat dissipation body, and a second insulating and thermally conductive layer laid on top of the first insulating and thermally conductive layer. This ensures a minimum dielectric breakdown voltage through the first insulating and thermally conductive layer, and the power semiconductor device is then fixed by the second insulating layer, guaranteeing that the power semiconductor device meets the performance requirements for torque withstand capability and junction-water thermal resistance. Specifically, the thickness of the second region is less than the thickness of the first region, and the thickness difference between the first and second regions is set to 2.5-5 times the thickness of the second region, ensuring that the torque withstand capability of the power device is greater than or equal to a set value. At the same time, the junction-to-water thermal resistance is made less than or equal to the set value, so that the dielectric breakdown voltage, torque withstand capability, and junction-to-water thermal resistance of the second region can achieve the optimal combination. In addition, the thickness difference between the first region and the second region is set to be 2.5-5 times the thickness of the second region, so that the insulating and thermally conductive material of the first region can have sufficient thickness to surround the periphery of the power semiconductor device during the bonding and curing process. This results in higher fixation stability of the power semiconductor device, making it less likely to fall off during use, and improving the torque withstand capability of the power semiconductor device. As a result, the yield of the final power semiconductor device is improved.

[0010] According to some embodiments of the present invention, the heat dissipation body is provided with a mounting surface, and the first insulating and thermally conductive layer is applied to the mounting surface by spraying and curing; the second insulating and thermally conductive layer is applied to the power semiconductor device by spraying and then cured on the first insulating and thermally conductive layer after the power semiconductor device is applied.

[0011] According to some embodiments of the present invention, the thickness of the first region is 0.12 mm to 0.15 mm, and the thickness of the second region is 0.02 mm to 0.04 mm.

[0012] According to some embodiments of the present invention, the thickness of the first insulating and thermally conductive layer is 0.12 mm to 0.15 mm.

[0013] According to some embodiments of the present invention, both the first insulating and thermally conductive layer and the second insulating and thermally conductive layer are made of epoxy resin material.

[0014] According to some embodiments of the present invention, the dielectric breakdown voltage of the second region is greater than 3KV.

[0015] According to some embodiments of the present invention, the power semiconductor device can withstand a torque greater than 40 kgf·cm.

[0016] According to some embodiments of this invention, the junction-to-water thermal resistance of the power semiconductor device is less than 1.5 (K / W).

[0017] Secondly, this utility model also provides a heat dissipation device for mounting a power semiconductor device, including a fixing structure for the power semiconductor device.

[0018] Thirdly, this utility model also provides a frequency converter, which includes at least the heat dissipation device on which the power semiconductor device is mounted. Attached Figure Description

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

[0020] Figure 1 This is a plan view of a fixed structure of a power semiconductor device provided in some embodiments of the present invention.

[0021] Explanation of reference numerals in the attached figures:

[0022] 1. Heat dissipation body; 2. First insulating and thermally conductive layer; 3. Second insulating and thermally conductive layer; 31. First region; 32. Second region; 4. Power semiconductor device. Detailed Implementation

[0023] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0024] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and 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," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0025] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0026] Furthermore, the technical features involved in the different embodiments of this utility model described below can be combined with each other as long as they do not conflict with each other.

[0027] Through research by the inventors of this utility model, it has been found that in the process of fixing power devices by spraying a resin thermally conductive insulating layer, the power devices need to be pressed, fixed and cured. However, the pressing, fixing and curing process can cause the power devices to shift, which means that the finished product cannot simultaneously meet the performance requirements such as dielectric breakdown voltage, torsional resistance, and junction-water thermal resistance, thus increasing the defect rate of the finished product.

[0028] To address the technical problem of power device displacement during the clamping and curing process, which prevents the finished product from simultaneously meeting performance requirements such as dielectric breakdown voltage, torque withstand capability, and junction-to-water thermal resistance, the following measures are taken: For example, excessively thick coating results in excessively high junction-to-water thermal resistance, while insufficiently thin coating leads to insufficient dielectric breakdown voltage and torque withstand capability. Furthermore, the thickness of the surrounding layer also affects the torque withstand capability. For instance, improperly setting the thickness of the first insulating thermally conductive layer 2 and the second insulating thermally conductive layer 3, as well as the thickness of the first region 31 and the second region 32, can increase the defect rate of the cured power device. (Refer to...) Figure 1 As shown, this utility model provides a fixing structure for a power semiconductor device 4, including: a heat dissipation body 1, a first insulating thermally conductive layer 2, and a second insulating thermally conductive layer 3. The first insulating thermally conductive layer 2 is laid on the heat dissipation body 1; the second insulating thermally conductive layer 3 is laid on the first insulating thermally conductive layer 2 and is used to attach and fix the power semiconductor device 4; the second insulating thermally conductive layer 3 has a first region 31 and several second regions 32, and the power semiconductor device 4 is attached and fixed in the second region 32; wherein, the thickness of the second region 32 is less than the thickness of the first region 31, and the thickness difference between the first region 31 and the second region 32 is set to be 2.5-5 times the thickness of the second region 32.

[0029] Specifically, the fixing structure of the power semiconductor device 4 provided by this utility model involves a first insulating and thermally conductive layer 2 laid on the heat dissipation body 1, and a second insulating and thermally conductive layer 3 laid on the first insulating and thermally conductive layer 2. This ensures a minimum dielectric breakdown voltage through the first insulating and thermally conductive layer 2. The power semiconductor device 4 is then fixed by the second insulating layer, ensuring that the power semiconductor device 4 meets the performance requirements for torque withstand capability and junction-water thermal resistance. Specifically, the thickness of the second region 32 is less than the thickness of the first region 31, and the thickness difference between the first region 31 and the second region 32 is set to be 2.5-5 times the thickness of the second region 32. This ensures that the torque withstand capability of the power device is greater than or equal to the set value. While setting a fixed value, the junction-to-water thermal resistance is made less than or equal to the set value. This allows the dielectric breakdown voltage, torque withstand capability, and junction-to-water thermal resistance of the second region 32 to achieve an optimal combination. In addition, the thickness difference between the first and second regions is set to be 2.5-5 times the thickness of the second region. This ensures that the insulating and thermally conductive material of the first region 31 has sufficient thickness to surround the periphery of the power semiconductor device 4 during the bonding and curing process. This results in a high degree of fixation stability for the power semiconductor device 4, making it less likely to fall off during use and improving the torque withstand capability of the power semiconductor device 4. As a result, the yield of the final power semiconductor device 4 is improved.

[0030] In some embodiments of this utility model, the heat dissipation body 1 is provided with a mounting surface, and the first insulating and heat-conducting layer 2 is applied to the mounting surface by spraying and curing; the second insulating and heat-conducting layer is applied to the power semiconductor device 4 by spraying and curing on the first insulating and heat-conducting layer 2 after the power semiconductor device 4 is applied.

[0031] Specifically, by using a spraying process to cure and lay the first insulating and thermally conductive layer 2 onto the mounting surface of the heat dissipation body 1, the adhesion between the insulating layer and the heat dissipation body 1 is uniform and tight, which is beneficial to improving heat conduction efficiency and enhancing the overall stability of the structure. Furthermore, by using a spraying process to cure and lay the second insulating and thermally conductive layer 3 onto the first insulating and thermally conductive layer 2 after the power semiconductor device 4 is attached, rapid bonding and reliable fixation of the power semiconductor device 4 are achieved, simplifying the process flow, reducing assembly difficulty, and effectively avoiding problems such as air bubbles or uneven laying caused by manual application. This improves insulation reliability and thermal conductivity consistency, and overall helps to extend the service life of the power semiconductor device 4 and improve the stability and safety of system operation. It is understood that the coating formed by spraying can achieve a strong mechanical bond with the surface of the heat dissipation body 1, reducing the risk of peeling caused by vibration or thermal cycling under long-term working conditions.

[0032] Understandably, the spraying process has good surface adaptability. Even if the mounting surface has certain curves or slight irregularities, it can ensure the coating is continuous and complete, thereby expanding the applicability of the fixing structure of this utility model. Because the spraying process can make the coating tightly cover the microscopic unevenness of the mounting surface, reducing interface gaps, it can effectively reduce thermal resistance and further improve heat conduction efficiency. The spraying process is suitable for mass production, and can quickly form the required coating thickness and structural shape, ensuring the consistency of each product in the fixing structure.

[0033] In some embodiments of this utility model, the thickness of the first region 31 is 0.12 mm to 0.15 mm, and the thickness of the second region 32 is 0.02 mm to 0.04 mm.

[0034] Specifically, the thickness of the first region 31, ranging from 0.12mm to 0.15mm, provides sufficient electrical insulation strength under high-voltage operating conditions while maintaining low thermal resistance. The thickness of the second region 32, ranging from 0.02mm to 0.04mm, significantly shortens the heat conduction path and improves heat transfer efficiency. The groove depth formed by the thickness difference is moderate, achieving stable mechanical positioning without increasing the difficulty of device assembly or affecting heat dissipation performance. This reasonable thickness combination reduces stress concentration caused by differences in the thermal expansion coefficients of different materials, minimizing the risk of cracking or detachment during long-term operation.

[0035] Understandably, this thickness range can be reliably achieved through conventional spraying or coating processes, and the thickness accuracy is easy to control, making it suitable for mass production.

[0036] In some embodiments of this utility model, the thickness of the first insulating and thermally conductive layer 2 is 0.12 mm to 0.15 mm.

[0037] Specifically, within the range of 0.12mm to 0.15mm, the first insulating thermally conductive layer 2 can provide low thermal resistance while ensuring high-voltage insulation requirements, thus ensuring efficient heat dissipation of the power semiconductor device 4. A reasonable thickness can avoid the decrease in thermal conductivity caused by an excessively thick insulating thermally conductive layer, and also avoid the risk of insulation breakdown caused by an excessively thin layer, thereby improving the reliability of the overall structure.

[0038] Preferably, the thickness of the first insulating and thermally conductive layer 2 is 0.12 mm, the thickness of the first region 31 of the second thermally conductive and insulating layer is 0.12 mm, and the thickness of the second region 32 is 0.03 mm.

[0039] In some embodiments of this utility model, the first insulating and thermally conductive layer 2 and the second insulating and thermally conductive layer 3 are both made of epoxy resin material.

[0040] Specifically, the epoxy resin exhibits excellent adhesion to the surfaces of the metal heat sink 1 and the power semiconductor device 4, maintaining a stable bond during long-term operation and reducing the risk of detachment due to vibration or thermal cycling. Epoxy resin also possesses good resistance to damp heat, chemical corrosion, and aging, making it suitable for long-term use under various harsh conditions, thus improving the reliability and service life of the fixed structure. The epoxy resin material can be molded using various processes such as spraying, potting, and molding, facilitating precise thickness control of the first insulating thermally conductive layer 2 and the second insulating thermally conductive layer 3, as well as mass production.

[0041] In some embodiments of this utility model, the dielectric breakdown voltage of the second region 32 is greater than 3KV. The dielectric breakdown voltage of the second region 32 refers to the dielectric breakdown voltage test performed on the second region 32 of the second thermally conductive insulating layer laid on the first insulating thermally conductive layer 2.

[0042] Specifically, the dielectric breakdown voltage is greater than 3KV, which can effectively prevent electrical breakdown during the operation of the power semiconductor device 4 and ensure safe and reliable operation. This indicator provides a large insulation safety margin for the long-term operation of the device and can maintain stable insulation performance even in humid, hot or dirty environments.

[0043] In some embodiments of this utility model, samples 1-6 are all made of 50×50×3mm aluminum material to form a heat dissipation body. A first insulating and thermally conductive layer is sprayed onto the heat dissipation body. After the first insulating and thermally conductive layer is cured, a second insulating and thermally conductive layer is sprayed onto it. After the second insulating and thermally conductive layer is cured, a test is performed. The thickness of the first insulating and thermally conductive layer is 0.12mm, and the thickness of the second insulating and thermally conductive layer is 0.03mm. The dielectric breakdown voltage of the heat dissipation body is tested. Samples 1 and 2 are tested after thermal shock, samples 3 and 4 are tested after alternating damp heat, and samples 5 and 6 are tested directly. The test data are shown in Table 1.

[0044] Table 1: Data Results and Parameters for Dielectric Breakdown Voltage Test

[0045]

[0046] According to the data in the table, the heat dissipation body provided in this application has a high energy-saving breakdown voltage, which can meet the insulation requirements of power semiconductor devices used in various low, medium and high voltage equipment, verifying the effectiveness of the present invention in terms of structural design and material selection.

[0047] In some embodiments of this invention, the power semiconductor device 4 has a torsional resistance greater than 40 kgf·cm.

[0048] In some embodiments of this utility model, samples 7-12 are all made of 50×50×3mm aluminum material to form a heat dissipation body. A first insulating and thermally conductive layer is sprayed on the heat dissipation body. After the first insulating and thermally conductive layer is cured, a second insulating and thermally conductive layer is sprayed on the first insulating and thermally conductive layer. Then, a single IGBT tube is attached to the sprayed second insulating and thermally conductive layer. After the second insulating and thermally conductive layer is cured, the test is performed. The total thickness of the second insulating and thermally conductive layer is 0.15mm, the thickness of the first insulating and thermally conductive layer is 0.12mm, the thickness of the first region of the second thermally conductive insulating layer is 0.12mm, the thickness of the second region is 0.03mm, and an IGBT tube (i.e., a power semiconductor device) is attached to the second region. The thickness of the IGBT tube package is 0.12mm. Torque tests are performed on the power semiconductor devices of samples 7-12. Among them, samples 7 and 8 are subjected to thermal shock before torsion testing, samples 9 and 10 are subjected to alternating damp heat before torsion testing, and samples 11 and 12 are directly subjected to torsion testing. The test data are shown in Table 2.

[0049] Table 2: Parameter Table of Torque Test Data Results

[0050]

[0051] According to the test results, the power semiconductor device provided in this application still has good mechanical connection reliability after experiencing environmental stresses such as thermal shock and alternating damp heat. The bonded power semiconductor device can withstand a torque of more than 40 kgf·cm without obvious loosening or failure, indicating that it has good environmental adaptability and structural stability.

[0052] Specifically, the high torque resistance can effectively resist rotational stress during installation or operation, preventing loosening or peeling between the insulating heat-conducting layer and the heat dissipation body or device. The high torque resistance reduces mechanical fatigue and material cracks, improving the long-term reliability of the overall structure.

[0053] In some embodiments of this invention, the junction-water thermal resistance of the power semiconductor device is less than 1.5 (K / W).

[0054] In some embodiments of this utility model, samples 14, 16, and 18 are all made of 50×50×3mm aluminum material to form a heat dissipation body. A first insulating and thermally conductive layer is sprayed onto the heat dissipation body. After the first insulating and thermally conductive layer cures, a second insulating and thermally conductive layer is sprayed onto it. Then, a single IGBT tube is attached to the sprayed second insulating and thermally conductive layer. Testing is performed after the second insulating and thermally conductive layer has cured. The total thickness of the second insulating and thermally conductive layer is 0.15mm, and the thickness of the first insulating and thermally conductive layer is 0.12mm. The thickness of one region is 0.12 mm, the thickness of the second region is 0.03 mm, and an IGBT single tube (i.e., a power semiconductor device) is attached to the second region. The thickness of the IGBT single tube package is 0.12 mm. The junction-to-water thermal resistance of the power semiconductor devices of samples 14, 16, and 18 was tested. Among them, sample 14 was tested after thermal shock, sample 16 was tested after alternating damp heat, and sample 18 was tested directly. The test data are shown in Table 3.

[0055] Table 3: Parameter Table of Thermal Resistance Test Results

[0056]

[0057] According to the data, the junction-to-water thermal resistance of power semiconductor devices is stable between 1.15 and 1.29 K / W, showing excellent thermal conductivity. According to the data, this value is lower than the thermal conductivity requirements of junction-to-water thermal resistance of various low, medium and high power semiconductor devices, and indicates that the aluminum-based heat dissipation body 1 and the double-layer insulating thermally conductive coating structure adopted in this application can maintain high insulation strength and mechanical stability while taking into account good thermal management performance.

[0058] Specifically, a low thermal resistance design can accelerate the heat transfer rate from the device junction temperature to the heat dissipation medium, such as water cooling or other cooling methods, thereby reducing the device's operating temperature. Under continuous high-power operation conditions, low thermal resistance helps to suppress performance drift caused by excessively high junction temperature, ensure stable electrical performance, effectively reduce operating temperature fluctuations, reduce solder joint cracking or material aging caused by thermal fatigue, and thus extend the overall service life.

[0059] Secondly, this utility model also provides a heat dissipation device on which a power semiconductor device 4 is mounted, including a fixing structure for the power semiconductor device 4.

[0060] Thirdly, this utility model also provides a frequency converter, which includes at least the heat dissipation device on which the power semiconductor device 4 is mounted.

[0061] Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. A fixed structure for a power semiconductor device, characterized in that, include: Heat dissipation body (1); A first insulating and thermally conductive layer (2) is laid on the heat dissipation body (1); The second insulating and thermally conductive layer (3) is laid on the first insulating and thermally conductive layer (2), and the second insulating and thermally conductive layer (3) is used to attach and fix the power semiconductor device (4); The second insulating and thermally conductive layer (3) has a first region (31) and a plurality of second regions (32), and the power semiconductor device (4) is attached and fixed in the second region (32); The thickness of the second region (32) is less than the thickness of the first region (31), and the thickness difference between the first region (31) and the second region (32) is set to 2.5-5 times the thickness of the second region (32).

2. The fixed structure of the power semiconductor device according to claim 1, characterized in that, The heat dissipation body (1) has an installation surface. The first insulating and heat-conducting layer (2) is applied to the installation surface by spraying and curing. The second insulating and heat-conducting layer is applied to the power semiconductor device (4) by spraying and curing after the power semiconductor device (4) is applied.

3. The fixed structure of the power semiconductor device according to claim 1, characterized in that, The thickness of the first region (31) is 0.12 mm to 0.15 mm, and the thickness of the second region (32) is 0.02 mm to 0.04 mm.

4. The fixed structure of the power semiconductor device according to claim 1, characterized in that, The thickness of the first insulating and thermally conductive layer (2) is 0.12 mm to 0.15 mm.

5. The fixed structure of the power semiconductor device according to claim 3 or 4, characterized in that, Both the first insulating and thermally conductive layer (2) and the second insulating and thermally conductive layer (3) are made of epoxy resin material.

6. The fixed structure of the power semiconductor device according to claim 1, characterized in that, The dielectric breakdown voltage of the second region (32) is greater than 3KV.

7. The fixed structure of the power semiconductor device according to claim 1, characterized in that, The power semiconductor device (4) has a torsional resistance greater than 40 kgf·cm.

8. The fixed structure of the power semiconductor device according to claim 1, characterized in that, The junction-water thermal resistance of the power semiconductor device (4) is less than 1.5 (K / W).

9. A heat sink with power semiconductor devices mounted on it, characterized in that, The fixed structure includes the power semiconductor device (4) according to any one of claims 1-8.

10. A frequency converter, characterized in that, It includes at least the heat dissipation device with the power semiconductor device (4) mounted as described in claim 9.

Images