An ultrasonic scanning fixture for automotive-grade IGBT modules

Abstract

The utility model relates to the technical field of semiconductor module packaging, specifically relates to a kind of ultrasonic scanning fixture for car gauge IGBT module, including bottom plate, recess for installing IGBT module is equipped on the bottom plate;Positioning column is set to the edge of the recess, with the copper substrate positioning hole of the IGBT module is matched;Wherein, the positioning column is nonmetal material;Upper cover plate is movably connected with the first side of the bottom plate, and the upper cover plate is equipped with the avoidance through-hole;Fastener is set to the second side of the bottom plate, and the upper cover plate forms separable connection. The utility model uses nonmetal positioning column to avoid copper substrate damage, recess and movable upper cover plate design realize quick positioning and stable clamping, avoidance through-hole ensures that probe is barrier-free scanning, improves detection efficiency and accuracy. Structure is simple and practical, and has protection and operation convenience, meet the high-precision requirement of IGBT module ultrasonic scanning.

Description

Technical Field

[0001] This utility model relates to the field of semiconductor module packaging technology, specifically to an ultrasonic scanning fixture for automotive-grade IGBT modules. Background Technology

[0002] Automotive-grade IGBT (Insulated Gate Bipolar Transistor) modules are core components of electric drive systems in new energy vehicles, and their reliability directly affects the performance and lifespan of the entire vehicle. IGBT modules typically consist of a copper substrate, a copper-clad ceramic (DBC) substrate, and electronic components such as chips. The chips are connected to the DBC, and the DBC to the copper substrate, via solder. Because IGBTs frequently switch on and off during operation, they generate a significant amount of heat. This heat must be transferred to the copper substrate through the DBC and ultimately dissipated. Therefore, the integrity of the solder joints is crucial for heat dissipation. If there are solder voids between the chip and the DBC, or between the DBC and the copper substrate, it can lead to increased localized thermal resistance, and in severe cases, even cause the chip to overheat and fail.

[0003] Currently, ultrasonic scanning is the primary method for detecting voids in weld layers. It utilizes pure water as the coupling medium and analyzes weld quality through sound wave reflection imaging. However, existing ultrasonic scanning fixtures are mostly one-piece metal structures, using metal positioning posts to fit into the screw holes of the IGBT module's copper substrate. During assembly or tightening, the hard contact between the metals can easily cause scratches or indentations on the copper substrate surface, affecting the module's heat dissipation performance and long-term reliability. Utility Model Content

[0004] To address the above technical issues, this utility model provides an ultrasonic scanning fixture for automotive-grade IGBT modules.

[0005] The technical problem solved by this utility model can be achieved by the following technical solution:

[0006] An ultrasonic scanning fixture for automotive-grade IGBT modules includes:

[0007] A base plate, wherein the base plate is provided with a groove for mounting an IGBT module;

[0008] A positioning post is disposed at the edge of the groove and matches the positioning hole of the copper substrate of the IGBT module; wherein, the positioning post is made of non-metallic material;

[0009] The upper cover plate is movably connected to the first side of the base plate, and the upper cover plate is provided with a clearance through hole;

[0010] Fasteners are provided on the second side of the base plate and form a detachable connection with the upper cover plate.

[0011] Preferably, the first end of the positioning post is provided with a threaded hole, and the positioning post is connected to the base plate by a screw passing through the threaded hole. The second end of the positioning post is connected to the positioning hole of the copper substrate of the IGBT module. The gap tolerance between the positioning post and the positioning hole of the copper substrate is less than 1mm.

[0012] Preferably, the coaxiality deviation of the positioning column is no greater than 0.05 mm.

[0013] Preferably, the second end of the positioning post is provided with a boss, and the chamfer of the boss is 45°.

[0014] Preferably, the positioning post is made of nylon.

[0015] Preferably, a sealing strip is provided around both the base plate and the clearance through hole.

[0016] Preferably, the first surface of the base plate is a plane with a flatness not exceeding 0.06 mm.

[0017] Preferably, the second surface of the base plate is provided with a groove, and at least four positioning posts are provided on the edge of the groove.

[0018] Preferably, the grooves are distributed in a modular matrix layout on the base plate.

[0019] Preferably, both the base plate and the top cover plate are made of aluminum.

[0020] The advantages or beneficial effects of this utility model are as follows: By using a non-metallic positioning post to replace the traditional metal positioning structure, this utility model effectively avoids the problem of scratches or indentations on the copper substrate surface caused by hard metal contact during assembly or locking; at the same time, the groove design, together with the movable top cover and fasteners, realizes the rapid positioning and stable clamping of the module, meeting the precise fixing requirements of the IGBT module during ultrasonic scanning; in addition, the design of avoiding through holes ensures that the ultrasonic probe can contact the measured area without obstruction, improving detection efficiency and accuracy; the overall structure is simple and practical, taking into account both protection and ease of operation. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0022] Figure 2 This is a schematic diagram of the base plate structure of this utility model;

[0023] Figure 3 This is a schematic diagram of the pin positioning post structure of this utility model;

[0024] Figure 4 This is a schematic diagram of the upper cover plate structure of this utility model;

[0025] Figure 5 This is a side sectional view of the present invention;

[0026] Explanation of reference numerals in the attached diagram: 1. Base plate; 2. Top cover plate; 3. Hinge; 4. Buckle; 5. Pin positioning post; 6. IGBT module; 7. Sealing strip; 8. Clearance through hole; 9. Screw; 10. Groove. Detailed Implementation

[0027] 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. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0028] It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments of the present invention can be combined with each other.

[0029] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the present invention.

[0030] Reference Figures 1 to 5 This utility model provides an ultrasonic scanning fixture for automotive-grade IGBT modules, comprising:

[0031] The base plate 1 has a groove 10 for mounting the IGBT module 6.

[0032] A positioning post is disposed on the edge of the groove 10 and matches the positioning hole of the copper substrate of the IGBT module 6; wherein, the positioning post is made of non-metallic material;

[0033] The upper cover plate 2 is movably connected to the first side of the bottom plate 1, and the upper cover plate 2 is provided with a clearance through hole 8;

[0034] Fasteners are provided on the second side of the base plate 1 and form a detachable connection with the upper cover plate 2.

[0035] Specifically, in this embodiment of the invention, the non-metallic positioning post and the groove 10 are used for positioning, which effectively reduces the risk of mechanical damage to the IGBT module 6 during the clamping process and achieves scratch-free fixing of the copper substrate surface; at the same time, the depth of the groove 10 of the base plate 1 matches the thickness of the IGBT module 6, ensuring uniform force during module installation; in addition, the movable connection between the upper cover plate 2 and the base plate 1 and the detachable fasteners effectively balance clamping stability and ease of operation, significantly improving the efficiency and consistency of batch testing of the IGBT module 6.

[0036] More specifically, the through hole 8 is used to expose the part to be scanned, which is packaged as DBC and chip. Its size and position correspond precisely to the key welding area of ​​IGBT module 6 (such as chip-DBC, DBC-copper substrate interface), ensuring that the ultrasonic probe can perform full coverage scanning of the welding layer without obstruction, avoiding detection blind spots caused by structural interference.

[0037] In a preferred embodiment of this utility model, a pin positioning post 5 is used. The pin positioning post 5 is made of non-metallic material, preferably nylon, hard plastic or other materials with a hardness lower than that of the copper substrate, so as to avoid scratches or indentations on the surface of the copper substrate during assembly.

[0038] In addition, the pin positioning post 5 can be replaced with a ceramic positioning post, a polyetheretherketone (PEEK) positioning post, or a rubber-coated metal positioning post to achieve the same effect.

[0039] Among them, ceramic positioning posts have the characteristics of high hardness, wear resistance and insulation, and their smooth surface will not damage the copper substrate; polyetheretherketone (PEEK) positioning posts have high strength, high temperature resistance and low coefficient of friction, making them suitable for long-term use; rubber-coated metal positioning posts have a soft rubber layer wrapped around the metal core, which can not only ensure positioning accuracy, but also buffer locking pressure and avoid hard contact damage.

[0040] These alternative solutions can all effectively protect the copper substrate surface of the IGBT module 6 while maintaining accurate positioning, thus meeting the clamping requirements of ultrasonic scanning.

[0041] In a preferred embodiment of the present invention, the first end of the pin positioning post 5 is provided with a threaded hole, and the positioning post is connected to the base plate 1 by a screw 9 passing through the threaded hole. The second end of the pin positioning post 5 is connected to the positioning hole of the copper substrate of the IGBT module 6.

[0042] Specifically, in this embodiment of the invention, the diameter of the pin positioning post 5 is smaller than the diameter of the positioning hole on the copper substrate to ensure smooth insertion during assembly. Simultaneously, the clearance is controlled within a reasonable range to avoid positioning deviations due to excessive looseness or assembly difficulties due to excessive tightness. This design ensures accurate positioning of the IGBT module 6 while reducing the risk of surface damage to the copper substrate caused by friction.

[0043] In a preferred embodiment of this utility model, the gap tolerance between the pin positioning post 5 and the positioning hole of the copper substrate is less than 1mm.

[0044] Specifically, in this embodiment of the invention, the gap tolerance is controlled within a range of less than 1 mm, ensuring that the shaking and movement range of the IGBT module 6 is within an acceptable range. This design ensures that the IGBT module 6 will not shift due to vibration or external force during clamping, while also preventing excessive tolerance from affecting the positioning accuracy of the ultrasonic scan, thereby effectively improving the stability and repeatability of the detection.

[0045] In a preferred embodiment of the present invention, the second end of the pin positioning post 5 is provided with a boss, and the chamfer of the boss is 45°.

[0046] Specifically, in this embodiment of the invention, the boss structure enhances the contact stability between the positioning post and the positioning hole of the copper substrate, while the 45° chamfer facilitates the guiding alignment during assembly, reduces assembly resistance or scratches on the copper substrate caused by misalignment, and further improves clamping efficiency and safety.

[0047] In a preferred embodiment of this utility model, the coaxiality deviation of the pin positioning post 5 is no greater than 0.05mm.

[0048] Specifically, in this embodiment of the invention, the strict standard of coaxiality deviation not exceeding 0.05mm ensures the precise alignment of the positioning post and the positioning hole of the copper substrate, avoiding local stress concentration or scanning probe positioning error caused by eccentricity, thereby ensuring the accuracy and reliability of the ultrasonic testing results.

[0049] In a preferred embodiment of this utility model, sealing strips 7 for sealing and waterproofing are provided around both the base plate 1 and the clearance through hole 8.

[0050] Specifically, in this embodiment of the invention, the sealing strip 7 is made of silicone or rubber and is bonded to the base plate 1 and the periphery of the through hole 8 by an interference fit, forming a reliable waterproof barrier. This design not only effectively prevents the coupling agent (such as water) from seeping into the IGBT module 6 during ultrasonic scanning and causing a short circuit risk, but also avoids detection errors caused by liquid residue, significantly improving the safety and stability of the testing environment.

[0051] In a preferred embodiment of the present invention, the first surface of the base plate 1 is a plane with a flatness not exceeding 0.06 mm; the second surface of the base plate 1 is provided with a groove 10, and at least 4 pin positioning posts 5 are provided on the edge of the groove 10; and the pin array can be 2 rows and 2 columns, 1 row and 2 columns, 1 row and multiple columns, etc.

[0052] Specifically, in this embodiment of the invention, the first surface of the base plate 1 is precision ground to ensure a flatness of less than 0.06mm, ensuring uniform contact pressure when pressed with the upper cover plate 2, and preventing stress concentration in the internal solder layer of the IGBT module 6 due to uneven force. The depth of the groove 10 on the second surface is customized according to the module thickness, so that the upper surface of the module is flush with the reference surface of the base plate 1 after insertion. When the positioning posts are arranged symmetrically in 2 rows and 2 columns, a high-precision positioning reference system is formed; the 1-row multi-column layout increases the number of transverse positioning posts to meet the bending resistance requirements of the long strip module, facilitating manual installation and fixing of the IGBT module 6.

[0053] More specifically, in this embodiment of the invention, at least four pin positioning posts 5 are provided on the edge of the groove 10. This is mainly an enhanced application of the three-point positioning principle: although three points can define a plane, four-point positioning can effectively overcome the potential minor deformation of the IGBT module 6 due to its own weight or assembly stress. At the same time, the four positioning posts are symmetrically distributed, which can evenly distribute the locking force and avoid excessive force on one side, causing warping of the copper substrate or positioning deviation. In addition, an extra positioning reference can significantly improve the vibration resistance stability of the module during the scanning process and ensure the relative positional accuracy of the ultrasonic probe and the detection area, which is particularly critical for the analysis of weld voids that require micron-level detection resolution.

[0054] In a preferred embodiment of this utility model, the grooves 10 are distributed on the base plate 1 in a modular matrix layout, wherein the array arrangement includes 2 rows and 2 columns, 1 row and multiple columns, etc., to complete the simultaneous scanning of multiple modules and improve scanning efficiency.

[0055] Specifically, in this embodiment of the invention, the modular matrix layout of the grooves 10 adopts a standardized spacing design. The row / column spacing can be adjusted according to different models of IGBT modules 6, ensuring sufficient operating space for the ultrasonic probe while achieving high-density integration of the fixture platform. Furthermore, the modular matrix layout allows the spacing between each groove unit to be precisely set according to the scanning range of the ultrasonic probe, ensuring no overlap or interference between the scanning areas of adjacent modules. The 2-row, 2-column layout is suitable for batch testing of square IGBT modules 6, using four-station synchronous scanning; while the 1-row, multi-column (e.g., 1×4) layout is optimized for elongated power modules, enabling continuous automated testing in conjunction with a linear scanning track. All groove units share the same set of high-precision positioning reference surfaces, ensuring data consistency during parallel testing of multiple modules, making it particularly suitable for the full inspection requirements of new energy vehicle electric drive system production lines.

[0056] In a preferred embodiment of the present invention, the upper cover plate 2 is movably connected to the first side of the base plate 1 via a hinge 3.

[0057] Specifically, in this embodiment of the utility model, the hinge 3 is made of stainless steel and has a built-in damping structure, so that the upper cover plate 2 can achieve stepless positioning and opening and closing from 0 to 180°, which not only ensures the stability of the flipping process, but also allows it to be suspended at any angle for easy operation.

[0058] In a preferred embodiment of this utility model, the fastener is a clasp 4.

[0059] Specifically, in this embodiment of the invention, the latch 4 is made of stainless steel and has a self-locking function. A uniform locking force can be generated by pressing down with one hand, ensuring that the IGBT module 6 is completely fitted into the groove 10. During operation, the positioning hole of the soldered copper substrate is aligned with the corresponding pin positioning post 5 manually or automatically and then placed upside down. After closing the upper cover plate 2, one side of the latch 4 is fastened to complete the overall sealing of the fixture, thereby completing the scanning of the IGBT module 6 and realizing the process of scanning the solder status after the power module is soldered.

[0060] In addition, other fasteners can be used, such as pneumatic quick clamps, rotary screw clamps, and intelligent electric clamps.

[0061] In a preferred embodiment of this utility model, both the base plate 1 and the top cover plate 2 are made of aluminum.

[0062] Specifically, in this embodiment of the invention, the base plate 1 and the upper cover plate 2 are made of 6061-T6 aluminum alloy, manufactured through CNC precision machining and aging heat treatment processes, possessing both high rigidity (tensile strength ≥310MPa) and lightweight characteristics (density only 1 / 3 that of steel). The surface undergoes hard anodizing treatment to form a 15-20μm oxide film, achieving a hardness of HV500 or higher, effectively resisting coupling agent corrosion and mechanical wear. The thermal expansion coefficient of this material is similar to that of the copper substrate of the IGBT module 6, maintaining dimensional stability of ≤0.02mm within a working temperature range of 40-120℃, ensuring that scanning positioning accuracy is unaffected by temperature changes. The internal reinforcing rib structure design controls the overall deformation to within 0.05mm / m, meeting the mechanical stability requirements of automotive-grade testing equipment.

[0063] In a preferred embodiment of this utility model, the base plate 1 and the upper cover plate 2 can be designed into corresponding shapes according to the different sizes and appearances of the modules. Specifically, this utility model can be designed to suit various ultrasonic scanning fixtures with different substrate sizes according to actual needs, with high compatibility. In the production process, it can more flexibly cope with various large automotive-grade power modules while ensuring production efficiency and quality.

[0064] The above description is only a preferred embodiment of the present utility model and does not limit the implementation method and protection scope of the present utility model. Those skilled in the art should realize that all solutions obtained by equivalent substitutions and obvious changes made based on the description and illustrations of the present utility model should be included within the protection scope of the present utility model.

Claims

1. An ultrasonic scanning fixture for automotive-grade IGBT modules, characterized in that, include: The base plate has grooves for mounting IGBT modules, and the grooves on the base plate are arranged in a modular matrix layout. A positioning post is disposed at the edge of the groove and matches the positioning hole of the copper substrate of the IGBT module; wherein, the positioning post is made of non-metallic material; The upper cover plate is movably connected to the first side of the base plate, and the upper cover plate is provided with a clearance through hole; Fasteners are provided on the second side of the base plate and form a detachable connection with the upper cover plate.

2. The ultrasonic scanning fixture for automotive-grade IGBT modules according to claim 1, characterized in that, The first end of the positioning post is provided with a threaded hole, and the positioning post is connected to the base plate by a screw passing through the threaded hole. The second end of the positioning post is connected to the positioning hole of the copper substrate of the IGBT module. The gap tolerance between the positioning post and the positioning hole of the copper substrate is less than 1mm.

3. The ultrasonic scanning fixture for automotive-grade IGBT modules according to claim 2, characterized in that, The coaxiality deviation of the positioning column is no greater than 0.05 mm.

4. The ultrasonic scanning fixture for automotive-grade IGBT modules according to claim 2, characterized in that, The second end of the positioning post is provided with a boss, and the chamfer of the boss is 45°.

5. The ultrasonic scanning fixture for automotive-grade IGBT modules according to claim 1, characterized in that, The positioning post is made of nylon.

6. The ultrasonic scanning fixture for automotive-grade IGBT modules according to claim 1, characterized in that, Sealing strips are provided around both the base plate and the clearance through hole.

7. The ultrasonic scanning fixture for automotive-grade IGBT modules according to claim 1, characterized in that, The first surface of the base plate is a plane, and its flatness does not exceed 0.06 mm.

8. The ultrasonic scanning fixture for automotive-grade IGBT modules according to claim 7, characterized in that, The second surface of the base plate is provided with a groove, and at least four positioning posts are provided on the edge of the groove.

9. The ultrasonic scanning fixture for automotive-grade IGBT modules according to claim 1, characterized in that, Both the base plate and the top cover plate are made of aluminum.

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