Method and jig for testing push-pull force of large-size solder joint for electronic package

Abstract

The present application relates to a kind of for large size (>400mm 2 ) welding sample push-pull force test fixture and test method. Since the direct heat dissipation structure is welded with heat sink using DBC (Direct Bonded Copper) substrate, the sample after welding needs high mechanical reliability, so it needs to test its shear strength and push-pull force fatigue reliability. The existing push-pull force test equipment is mostly used for chip samples, and the upper limit of push-pull force is usually less than 2,000N, while the push-pull force requirement of DBC sample is usually more than 8,000N, and the existing equipment cannot meet the requirements. The present application designs a push-pull force test fixture suitable for large size samples, which consists of a limiting cover plate, a push head, a base and a sample fixing clamp, which can effectively stabilize the sample and ensure uniform stress. In addition, the present application also proposes a method for optimizing test precision to ensure the reliability of test results. The fixture and method can meet the push-pull force test requirements of large size welding samples and promote the development of electronic packaging technology.

Description

Technical Field

[0001] This invention relates to semiconductor device packaging technology, specifically a test method and fixture for testing the push-pull force of large-size soldered samples. Background Technology

[0002] In modern electronic devices, with the continuous increase in power density, thermal management has become a crucial issue in the field of electronic packaging. Directly bonded copper (DBC) substrates and heat sinks are widely used due to their excellent heat dissipation performance. However, DBCs are an order of magnitude larger than chips, making the mechanical reliability of the bonded samples particularly important, as this directly affects the long-term stability and performance of electronic devices.

[0003] Current push-pull force testing equipment for electronic packaging is mainly suitable for small-sized soldered samples, and its upper limit of push-pull force is usually less than 2000N, which cannot meet the requirements of large-sized samples (such as 400mm). 2 The need for mechanical property testing under high load conditions. This technical bottleneck prevents a comprehensive assessment of the reliability of large-size welded samples, thus affecting the application and development of related products.

[0004] Therefore, there is an urgent need for a dedicated push-pull force testing method and fixture to meet the testing requirements of large-size soldered samples. Such a fixture design will help improve testing accuracy and reliability, thereby promoting the development of electronic packaging technology and meeting the industry's stringent standards for high-performance soldered samples. Summary of the Invention

[0005] This invention relates to the field of electronic packaging, specifically a dedicated testing method and fixture for push-pull force testing of large-size soldered samples. This fixture is specifically designed for samples larger than 400mm. 2 The design of the welded sample aims to address the problem of insufficient testing capability of existing equipment for large-size samples.

[0006] Since the direct heat dissipation structure employs welding of the DBC substrate to the heat sink, the welded sample must possess high mechanical reliability to ensure stability and performance during long-term use. Therefore, systematic testing of its shear strength and push-pull fatigue reliability is particularly important. Currently, existing push-pull force testing equipment is mainly designed for small-sized samples, with a typical upper limit of less than 2,000 N. This cannot meet the testing requirements of large-sized samples (greater than 8,000 N) under high-load conditions, resulting in insufficient evaluation of the mechanical properties of welded samples.

[0007] To address this issue, this invention presents a dedicated push-pull force testing method and fixture, which features a rational structure and can effectively perform precise mechanical property testing on large-sized samples. The fixture consists of four main parts: a limiting cover plate, a pusher head, a base, and a sample clamp. The limiting cover plate is securely connected to the base with six fixing bolts, ensuring that the pusher head remains parallel to the welding surface when applying push-pull force. The linkage mechanism of the sample clamp allows for 90° rotation, facilitating sample insertion and removal and ensuring sample stability during testing.

[0008] Furthermore, the fixture design fully considers material strength. The pusher and base are made of 45 steel with a thickness of 15mm or more, or other high-strength materials with a yield strength exceeding 600MPa, to meet the requirements of high-load testing. Meanwhile, the fixture base has square holes and 3 / 4 round holes at the four corners to avoid interference at the sample edges and corners, facilitating smooth sample loading and unloading.

[0009] The testing method and fixture of this invention enable effective push-pull force testing of large-size welded samples, significantly improving the accuracy and reliability of the test, promoting the development of electronic packaging technology, and providing strong support for industry standards for high-performance welded samples. Attached Figure Description

[0010] Figure 1 This is a schematic diagram of the large-size push-pull force testing fixture of the present invention;

[0011] Figure 2 This is the fixing cover plate of the fixture shown;

[0012] Figure 3 It is the push head of the fixture shown;

[0013] Figure 4 It is the base of the fixture shown;

[0014] Figure 5 This is the sample clamp of the fixture shown;

[0015] Figure 6 This is a schematic diagram of the cross-section after the sample has been placed inside;

[0016] Figure 7 This is a three-dimensional schematic diagram after the sample has been placed inside.

[0017] In the diagram: 1. Fixed cover plate, 2. Push head, 3. Base, 4. Sample fixing clamp. Detailed Implementation

[0018] The specific embodiments of the present invention are described in detail below through examples illustrating the push-pull force testing method and fixture of the present invention. It should be understood that these embodiments are for illustrative purposes only and do not limit the scope of protection of the present invention.

[0019] Example 1: Design and manufacture of push-pull force testing fixture

[0020] The push-pull force testing fixture of this invention mainly consists of four parts: a limiting cover plate, a push head, a base, and a sample fixing clamp. All components are made of high-strength materials with a yield strength exceeding 600 MPa to meet the testing requirements under high load conditions. The specific design of each part is as follows:

[0021] Limiting cover: Made of 8mm thick 45 steel, with a heat-treated surface to improve strength. The limiting cover is fixed to the base with six M8 bolts to ensure effective restriction of the push head's movement when push or pull forces are applied.

[0022] Pusher head: The pusher head has a 32mm×32mm square hole in the center and is made of 45 steel with a thickness of 15mm. This square hole design can accommodate welding samples of different thicknesses and ensure uniform force distribution when applied.

[0023] Base: The base is 20mm thick and has a 35mm×35mm square hole and four 3 / 4 round holes to facilitate the placement and removal of samples.

[0024] Sample clamp: The sample clamp adopts a linkage mechanism design, which can rotate 90°, making it easy to put in and take out the sample, and ensuring the sample is stable during the test.

[0025] Example 2: Push-Pull Force Test Method

[0026] Select mechanical testing equipment that meets the testing standards for the estimated force load and calibrate it to ensure measurement accuracy. Ensure the ambient temperature is maintained between 20°C and 25°C, and the relative humidity is controlled between 50±10%. Select welded samples and visually inspect them to confirm they are free of defects. Place the samples in the fixture and secure them with clamps. Subsequent testing steps are as follows:

[0027] 1) Start the push-pull force testing instrument and set the load loading mode to displacement 0.7mm / s;

[0028] 2) Begin applying push-pull force and monitor the sample status in real time;

[0029] 3) When the sample breaks or reaches the predetermined maximum tensile force, stop applying the load and record the data.

[0030] 4) After the test, record the maximum push-pull force at fracture and other relevant data. Analyze the data according to standard requirements to evaluate the tensile strength and reliability of the welded sample, and issue a detailed test report.

[0031] Through the above embodiments, the present invention provides an efficient and reliable method and fixture for testing the push-pull force of large-size welded samples, which significantly improves the performance evaluation capability of welded samples under high load conditions and provides strong support for the development of electronic packaging technology.

[0032] Example 3: Reliability Testing Methods

[0033] Select mechanical testing equipment that meets the testing standards for the estimated force load and calibrate it to ensure measurement accuracy. Ensure the ambient temperature is maintained between 20°C and 25°C, and the relative humidity is controlled between 50±10%. Select welded samples and visually inspect them to confirm they are free of defects. Place the samples in the fixture and secure them with clamps. Subsequent testing steps are as follows:

[0034] 1) Start the push-pull force testing instrument, set the load loading mode to push force 20N, and apply the preload;

[0035] 2) Begin applying push-pull force and monitor the sample status in real time;

[0036] 3) Stop applying the load when it reaches 20N;

[0037] 4) Set the load size, load frequency, and number of cycles, and then conduct the test;

[0038] 5) After the test, record the maximum tensile force at fracture, the number of cycles, and other relevant data. Analyze the data according to standard requirements to evaluate the tensile strength and reliability of the welded sample, and issue a detailed test report.

[0039] Through the above embodiments, the present invention provides an efficient and reliable method and fixture for testing the push-pull force of large-size welded samples, which significantly improves the performance evaluation capability of welded samples under high load conditions and provides strong support for the development of electronic packaging technology.

[0040] The above embodiments are merely one specific example of the present invention and do not limit the scope of protection of the present invention. Any modifications, alterations, or substitutions made to the present invention should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A large-size (>400mm) 2 The welding sample push-pull force test fixture consists of four main parts: limit cover plate, push head, base and sample fixing clamp.

2. The fixture as described in claim 1, characterized in that... The limiting cover is fixed to the base with 6 fixing bolts. The limiting cover ensures that the push head is always parallel to the welding surface when applying push and pull force.

3. The fixture as described in claim 1, wherein the base is fixed to the sample clamp by four bolts, and the linkage mechanism of the sample clamp can rotate 90°, which facilitates the insertion and removal of the welding sample and ensures that the sample remains stable during the test.

4. The fixture as described in claim 1, wherein the sample holder can adaptively weld the sample thickness using studs and remain fixed.

5. As described in claim 1, to ensure that the jig can withstand a thrust of up to 8,000 N or more, the push head and base must be made of 45# steel with a thickness of 15 mm or more, or other materials with a yield strength exceeding 600 MPa. The thickness can be appropriately increased based on the welding area and the estimated stress.

6. As described in claim 1, in order to ensure that the limiting cover plate can limit the component force perpendicular to the welding surface, it is necessary to use 6 fixing bolts to fix it to the base, and ensure that the feature dimension of the cover plate is greater than 5mm to avoid deformation.

7. The fixture as described in claim 1, wherein the base has a square hole with dimensions of 35×35mm. 2 Other sizes can be used depending on the sample size. Three-quarter diameter holes are machined at the four corners to avoid interference at the sample corners and to facilitate sample handling.

8. The fixture as described in claim 1, wherein the push head has a square hole in the center. The square hole is 32×32mm in size. 2 For other dimensions, the size should be smaller than the square hole size of the base.

9. The fixture as described in claim 1, after the sample is placed in, the upper surface of the lower plate of the sample contacts the lower surface of the pusher, while the upper plate of the sample is placed in the square hole of the pusher, and the test is performed by applying a pushing and pulling force by moving the pusher back and forth.

10. The dimensions of the lower plate of the welding test sample are consistent with the dimensions of the square hole in the base, while the dimensions of the upper plate are smaller than the dimensions of the pusher head.

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