Ultrasonic and eddy current compound nondestructive testing device for IGBT copper and ceramic interface

Abstract

This utility model discloses an ultrasonic and eddy current composite non-destructive testing device for the copper-ceramic interface of IGBTs, including a testing platform. A support column is fixedly installed on the top of the testing platform, and a top support plate is fixedly installed on the top of the support column. A three-axis drive mechanism is installed on the top support plate, and an ultrasonic probe and an eddy current probe are installed below the three-axis drive mechanism. The ultrasonic probe adopts an air-coupled ultrasonic transducer with a frequency range of 20-100MHz, which does not require liquid coupling agent and avoids contamination. It relates to the field of semiconductor power device testing technology. It integrates an ultrasonic probe and an eddy current probe into one unit, which can work synchronously or alternately. The ultrasonic + eddy current complementarity can detect micro-delamination and cracks ≥30μm, improving the detection effect. The use of air-coupled ultrasound avoids contamination and is suitable for cleanrooms.

Description

Technical Field

[0001] This utility model relates to the field of semiconductor power device testing technology, specifically to an ultrasonic and eddy current composite non-destructive testing device for the copper-ceramic interface of IGBTs. Background Technology

[0002] As core power devices in new energy vehicles, rail transit, and smart grids, the reliability of IGBT modules directly affects the safe operation of the entire system. The DBC substrate is a critical structure of the IGBT module, consisting of two layers of high-purity copper foil bonded to both sides of a ceramic substrate using high-temperature eutectic bonding or active metal brazing (AMB) processes. However, during manufacturing, due to thermal stress, mismatched material expansion coefficients, and fluctuations in welding processes, interface defects such as delamination, micro-cracks, and voids easily occur between the copper layer and the ceramic substrate. These defects significantly reduce the substrate's thermal conductivity, mechanical strength, and electrical insulation performance, leading to localized overheating, increased thermal resistance, and even thermal failure during module use. Existing testing methods have significant limitations.

[0003] Traditional ultrasonic C-scan (UT): It can effectively detect large-area delamination, but has low sensitivity to shallow surface micro-defects (<50μm); it requires a coupling agent (water or oil), which may contaminate the sample, and is not suitable for online detection.

[0004] Infrared thermal imaging (IRT): Based on the principle of thermal wave reflection, but with limited resolution, it is difficult to locate tiny defects; it is also susceptible to surface emissivity, resulting in unstable results.

[0005] X-ray inspection provides clear imaging of internal structures, but is insensitive to interface defects (such as delamination) parallel to the surface; it requires high radiation protection and is expensive.

[0006] Single eddy current testing (ECT): suitable for surface / near-surface defect detection of conductive materials, without the need for coupling agent; however, the penetration depth is limited (usually <1mm), making it difficult to detect deep copper-ceramic interfaces; response to non-conductive ceramic substrates. Utility Model Content

[0007] In view of the problems existing in the current ultrasonic and eddy current composite nondestructive testing device for the interface between IGBT copper and ceramic, this utility model is proposed.

[0008] Therefore, the purpose of this invention is to provide a composite ultrasonic and eddy current nondestructive testing device for the IGBT copper-ceramic interface, which solves the problems existing in the testing of the IGBT copper-ceramic interface.

[0009] To solve the above-mentioned technical problems, according to one aspect of the present invention, the present invention provides the following technical solution:

[0010] An ultrasonic and eddy current composite non-destructive testing device for the copper-ceramic interface of IGBTs includes a testing platform, a support column fixedly installed on the top of the testing platform, a top support plate fixedly installed on the top of the support column, a three-axis drive mechanism installed on the top support plate, and an ultrasonic probe and an eddy current probe installed below the three-axis drive mechanism.

[0011] As a preferred embodiment of the ultrasonic and eddy current composite non-destructive testing device for the IGBT copper-ceramic interface described in this utility model, the ultrasonic probe adopts an air-coupled ultrasonic transducer with a frequency range of 20-100MHz, which does not require liquid coupling agent and avoids contamination.

[0012] As a preferred embodiment of the ultrasonic and eddy current composite nondestructive testing device for the IGBT copper-ceramic interface described in this utility model, the eddy current probe adopts a differential planar coil with an excitation frequency of 100kHz-10MHz, and is used to detect early damage near the surface of the copper layer and the interface.

[0013] As a preferred embodiment of the ultrasonic and eddy current composite non-destructive testing device for the IGBT copper-ceramic interface described in this utility model, a distance sensor is installed at the bottom of both the ultrasonic probe and the eddy current probe.

[0014] As a preferred embodiment of the ultrasonic and eddy current composite nondestructive testing device for the IGBT copper-ceramic interface described in this utility model, the three-axis drive mechanism includes a first guide rail plate slidably connected to a top support plate, a second guide rail plate slidably connected to the first guide rail plate, a support block welded to the rear end of the first guide rail plate, a first electric push rod installed between the support block and the second guide rail plate, an L-shaped support plate welded to the support column, a second electric push rod installed between the L-shaped support plate and the first guide rail plate, two third electric push rods installed at the bottom of the second guide rail plate, and the ultrasonic probe and the eddy current probe respectively fixedly installed at the bottom of the two third electric push rods.

[0015] As a preferred embodiment of the ultrasonic and eddy current composite nondestructive testing device for the IGBT copper-ceramic interface described in this utility model, a fixture is installed on the testing platform.

[0016] As a preferred embodiment of the ultrasonic and eddy current composite nondestructive testing device for the IGBT copper-ceramic interface described in this utility model, it further includes a signal excitation and acquisition unit, a multimodal signal processing and analysis unit, and a human-computer interaction and result display system.

[0017] The signal excitation and acquisition unit includes an ultrasonic pulse transmission and reception module, an eddy current excitation and demodulation module, and a high-speed data acquisition card.

[0018] Compared with existing technologies:

[0019] Integrating an ultrasonic probe and an eddy current probe, it can work synchronously or alternately. The ultrasonic and eddy current complementarity can detect tiny delaminations and cracks ≥30μm, improving the detection effect. It adopts air-coupled ultrasound to avoid contamination and is suitable for cleanrooms. Attached Figure Description

[0020] Figure 1 This is a structural schematic diagram of the present invention;

[0021] Figure 2 Provided by this utility model Figure 1 A partial bottom view;

[0022] Figure 3 A flowchart of the detection preparation stage provided for this utility model;

[0023] Figure 4 A flowchart of the detection execution stage provided by this utility model;

[0024] Figure 5 A flowchart of the data processing and analysis stage provided by this utility model;

[0025] Figure 6 The flowchart shows the result output and subsequent processing provided by this utility model.

[0026] In the diagram: 1. Testing table; 2. Fixture; 3. Support column; 4. Top support plate; 5. L-shaped support plate; 6. First guide rail plate; 61. Support block; 7. Second guide rail plate; 8. Third electric push rod; 10. Ultrasonic probe; 11. Eddy current probe; 12. Second electric push rod; 13. First electric push rod. Detailed Implementation

[0027] To make the objectives, technical solutions, and advantages of this utility model clearer, the embodiments of this utility model will be described in further detail below with reference to the accompanying drawings.

[0028] This invention provides a device for ultrasonic and eddy current combined nondestructive testing of the IGBT copper-ceramic interface. Please refer to [link to relevant documentation]. Figure 1-6 The system includes a testing platform 1, on which a fixture 2 is installed. The fixture 2 can be any type of fixture used for testing the copper and ceramic interfaces of IGBTs. A support column 3 is fixedly installed on the top of the testing platform 1, and a top support plate 4 is fixedly installed on the top of the support column 3. A three-axis drive mechanism is installed on the top support plate 4, and an ultrasonic probe 10 and an eddy current probe 11 are installed below the three-axis drive mechanism.

[0029] The ultrasonic probe 10 uses an air-coupled ultrasonic transducer with a frequency range of 20-100MHz, which does not require liquid coupling agent and avoids contamination.

[0030] The eddy current probe 11 uses a differential planar coil with an excitation frequency of 100kHz-10MHz to detect early damage near the surface and interface of the copper layer.

[0031] Both the ultrasonic probe 10 and the eddy current probe 11 have distance sensors installed at their bottoms.

[0032] The three-axis drive mechanism includes a first guide plate 6 slidably connected to the top support plate 4, a second guide plate 7 slidably connected to the first guide plate 6, a support block 61 welded to the rear end of the first guide plate 6, a first electric push rod 13 installed between the support block 61 and the second guide plate 7, an L-shaped support plate 5 welded to the support column 3, a second electric push rod 12 installed between the L-shaped support plate 5 and the first guide plate 6, two third electric push rods 8 installed at the bottom of the second guide plate 7, and the ultrasonic probe 10 and the eddy current probe 11 respectively fixedly installed at the bottom of the two third electric push rods 8.

[0033] It also includes a signal excitation and acquisition unit, a multimodal signal processing and analysis unit, and a human-computer interaction and result display system;

[0034] The signal excitation and acquisition system includes an ultrasonic pulse transmission and reception module, an eddy current excitation and demodulation module, and a high-speed data acquisition card. The multimodal signal processing and analysis unit includes a main control computer, dedicated algorithm software, and an AI defect identification module. The algorithm software can perform data fusion processing on ultrasonic A / B / C scan images and eddy current impedance maps. The AI ​​module automatically identifies and classifies defect types such as delamination, cracks, and cavities based on deep learning models (such as CNN). The human-computer interaction and result display system is equipped with a touch screen to display composite inspection images in real time; it outputs an inspection report, including defect location, area, depth estimation, and risk level.

[0035] Both the IGBT copper-ceramic interface ultrasonic nondestructive testing system and the eddy current composite nondestructive testing system are existing technologies, and the system in this application consists of these two existing testing systems.

[0036] In practical use, the IGBT module under test is fixed to the sample fixture 2. The second guide plate 7 moves along the X and Y axes by extending and retracting the second electric push rod 12 and the first electric push rod 13, thus moving the ultrasonic probe 10 and the eddy current probe 11 along the X and Y axes. The third electric push rod 8 moves the ultrasonic probe 10 and the eddy current probe 11 along the Z axis, thereby controlling the ultrasonic probe 10 and the eddy current probe 11 to be positioned above the IGBT module under test. The air-coupled probe emits high-frequency sound waves that penetrate the copper layer and are reflected at the copper-ceramic interface. The echo signal is received, generating a C-scan image to identify large-area delamination. The test is performed according to the testing procedure. An alternating magnetic field induces eddy currents in the copper layer. Interface defects disturb the eddy current field, changing the coil impedance. Microcracks and early debonding are identified through impedance diagrams. The signal acquisition system simultaneously acquires both types of data and transmits them to the analysis unit. The software performs pixel-level fusion of the ultrasonic and eddy current images, and the AI ​​module comprehensively judges the nature of the defects. After the test is completed, a visual report is automatically generated.

[0037] Although the present invention has been described above with reference to embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the present invention. In particular, as long as there is no structural conflict, the features in the embodiments disclosed in this invention can be combined with each other in any way. The lack of an exhaustive description of these combinations in this specification is merely for the sake of brevity and resource conservation. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A composite ultrasonic and eddy current nondestructive testing device for the interface between IGBT copper and ceramic, comprising a testing table (1), wherein a support column (3) is fixedly installed on the top of the testing table (1), a top support plate (4) is fixedly installed on the top of the support column (3), and a three-axis drive mechanism is installed on the top support plate (4), characterized in that: An ultrasonic probe (10) and an eddy current probe (11) are mounted below the triaxial drive mechanism.

2. The ultrasonic and eddy current combined nondestructive testing device for the IGBT copper-ceramic interface according to claim 1, characterized in that, The ultrasonic probe (10) uses an air-coupled ultrasonic transducer with a frequency range of 20-100MHz, which does not require liquid coupling agent and avoids contamination.

3. The ultrasonic and eddy current combined nondestructive testing device for the IGBT copper-ceramic interface according to claim 2, characterized in that, The eddy current probe (11) uses a differential planar coil with an excitation frequency of 100kHz-10MHz to detect early damage near the surface and interface of the copper layer.

4. The ultrasonic and eddy current combined nondestructive testing device for the IGBT copper-ceramic interface according to claim 3, characterized in that, Both the ultrasonic probe (10) and the eddy current probe (11) are equipped with distance sensors at their bottoms.

5. The ultrasonic and eddy current combined nondestructive testing device for the IGBT copper-ceramic interface according to claim 2, characterized in that, The three-axis drive mechanism includes a first guide plate (6) slidably connected to the top support plate (4), a second guide plate (7) slidably connected to the first guide plate (6), a support block (61) welded to the rear end of the first guide plate (6), a first electric push rod (13) installed between the support block (61) and the second guide plate (7), an L-shaped support plate (5) welded to the support column (3), a second electric push rod (12) installed between the L-shaped support plate (5) and the first guide plate (6), two third electric push rods (8) installed at the bottom of the second guide plate (7), and the ultrasonic probe (10) and the eddy current probe (11) respectively fixedly installed at the bottom of the two third electric push rods (8).

6. The ultrasonic and eddy current combined nondestructive testing device for the IGBT copper-ceramic interface according to claim 3, characterized in that, The testing station (1) is equipped with a clamp (2).

7. The ultrasonic and eddy current combined nondestructive testing device for the IGBT copper-ceramic interface according to any one of claims 2-5, characterized in that, It also includes a signal excitation and acquisition unit, a multimodal signal processing and analysis unit, and a human-computer interaction and result display system; Signal excitation and acquisition includes an ultrasonic pulse transmission and reception module, an eddy current excitation and demodulation module, and a high-speed data acquisition card.

Images