A solderability testing apparatus and method for BGA devices

Abstract

The application discloses a solderability test device and test method suitable for BGA devices, and belongs to the technical field of destructive physical analysis and failure analysis of electronic components and devices. The device solves the technical problems of poor applicability of existing clamps to BGA devices with large size span and difficulty in adjusting the clamping size. The solderability test device comprises a clamp body and a connecting piece. The clamp body is fixedly connected with the connecting piece. The clamp body comprises a fixed block and first and second side clamps arranged in parallel. The first and second side clamps each comprise a clamping end and a fixed end, and are connected with the fixed block through the respective fixed ends. The first and second side clamps are arranged perpendicularly to the fixed block. The first and second side clamps are used for clamping the BGA device. The fixed block is arranged perpendicularly to the connecting piece and is connected with the connecting piece in a sliding mode. The connecting piece is fixedly connected with a solderability tester. The device can stably clamp BGA devices of different sizes and provide support for smooth solderability test.

Description

Technical Field

[0001] This invention relates to the field of destructive physical analysis and failure analysis of electronic components, and in particular to a solderability testing device and method suitable for BGA devices. Background Technology

[0002] The main purpose of solderability testing is to detect whether a material can achieve a defect-free weld during the welding process and to ensure that the performance of the welded joint meets the usage requirements. BGA (Ball Grid Array Package) is a package whose external leads are solder balls or solder bumps, which are arranged in an array on the bottom plane of the package substrate. There are generally two principles for solderability testing of BGA devices: reflow simulation principle and wetting weighing principle. Generally, the wetting weighing principle is more convenient and is the path chosen by many analytical institutions. The joint industry standard IPC J-STD-002E, "Solderability Testing of Component Leads, Solder Ends, Solder Sheets, Terminals and Wires," specifies in sections 4.3.3 "Test G" and 4.3.6 "Test G1" that the wetting weighing solder ball test "should use appropriate clamps" to hold the component and "avoid contaminating the surface to be tested."

[0003] Existing technologies generally use the built-in fixtures of commercially available solderability testers for testing, which can only hold a very small number of BGAs. These BGAs have small solder ball pitches, and even if they are held, wetting will fail. Most BGA devices are relatively large (about 15mm x 15mm in length and width), and the built-in fixtures of existing commercially available solderability testers cannot hold them as required by IPC specifications. Therefore, existing solderability testing techniques lack a suitable wetting, weighing, and clamping technique for BGA devices. The industry often removes the BGA solder balls and clamps them individually onto the instrument's fixture for testing. This approach has several drawbacks: first, it easily damages the test object (solder ball) during the removal process, and mechanical damage to the plating can interfere with the test results; second, processing each ball individually is tedious, and clamping the tiny balls heavily relies on the operator's hand-eye coordination, resulting in a high failure rate; third, clamping the solder balls requires preventing the fixture end from obstructing contact between the solder ball and the solder. If the solder ball is exposed too little, wetting fails and an invalid curve is drawn; if it is exposed too much, the clamping is unstable, and the ball is prone to slipping off the fixture during the test, leading to test failure. Furthermore, this method inevitably causes unwanted contact between the equipment fixture and the solder, damaging the fixture and making cleaning difficult.

[0004] Due to the large size range of different BGA devices, and the dense distribution of solder balls or solder bumps to be tested on the bottom plane of the package substrate, in order to meet the standard requirements and stably clamp BGA devices of various sizes to complete the solderability test without contaminating the solder balls or solder bumps to be tested, it is necessary to design a clear and specific solderability test device and method applicable to BGA devices. Summary of the Invention

[0005] Based on the above analysis, the present invention aims to provide a solderability test method for BGA devices to solve the problems of poor applicability of existing fixtures to BGA devices with large size range, difficulty in adjusting the clamping size, the need to exert great force with fingers in a very small space, and the easy occurrence of metal fatigue and scrapping of the fixture.

[0006] The objective of this invention is mainly achieved through the following technical solutions:

[0007] This invention provides a solderability testing device suitable for BGA devices, comprising a fixture body and a connector; the fixture body and the connector are fixedly connected.

[0008] The clamp body includes a fixing block and a first side clamp and a second side clamp arranged in parallel; both the first side clamp and the second side clamp include a clamping end and a fixing end, and both are connected to the fixing block through their respective fixing ends; both the first side clamp and the second side clamp are arranged perpendicular to the fixing block;

[0009] The first and second side clamps are used together to hold the BGA device; the fixing block and the connector are set perpendicularly and are slidably connected; the connector is fixedly connected to the solderability tester.

[0010] In one possible design, the fixing block is rectangular in shape;

[0011] The fixed block has a groove inside along its length; the opening direction of the groove is parallel to the first and second side clamps; the connector includes a sliding end and a connecting end; the sliding end passes through the groove and can slide along the length of the groove; the connecting end is used for fixed connection with the weldability tester.

[0012] In one possible design, inner fastening nuts and outer fastening nuts are provided on the sliding ends located on both sides of the groove.

[0013] When it is necessary to move or fix the connecting rod, adjust the outer fastening nut so that the sliding end of the connecting rod can slide or lock in the groove.

[0014] In one possible design, the fixed end of the first side clamp is fixedly connected to the first end of the fixed block;

[0015] The fixed end of the second side clamp is provided with a through groove, the opening direction of the through groove is the same as the length direction of the fixed block, the second end of the fixed block passes through the through groove, and the fixed end of the second side clamp is slidably connected to the fixed block through its through groove.

[0016] In one possible design, the fixed end of the first side clamp is provided with a first transverse threaded hole, and the first end of the fixing block is threadedly connected to the fixed end of the first side clamp.

[0017] The fixed end of the second side clamp is provided with a vertical second threaded hole, and a first fastening screw is provided in the second threaded hole. Adjusting the first fastening screw can adjust the relative position between the fixed end of the second side clamp and the fixed block.

[0018] In one possible design, the first side clamp includes a first connecting plate and a first wedge-shaped clamp, and the second side clamp includes a second connecting plate and a second wedge-shaped clamp.

[0019] In one possible design, one end of the first connecting plate is connected to the first wedge-shaped clamp, and the other end is fixedly connected to the first end of the fixing block;

[0020] One end of the second connecting plate is fixedly connected to the second wedge-shaped clamp, and the other end is slidably connected to the second end of the fixing block.

[0021] In one possible design, the first connecting plate and the second connecting plate are parallel to each other and have the same structure, and the first wedge-shaped clamp and the second wedge-shaped clamp have the same structure and are parallel to each other.

[0022] In one possible design, the clamp body also includes a side clamp fixing rod;

[0023] The first connecting plate of the first side clamp is provided with a third threaded hole, and the second connecting plate of the second side clamp is provided with a fourth threaded hole. The threads of the third threaded hole and the fourth threaded hole are opposite in direction.

[0024] The length of the side clamp fixing rod is greater than the distance between the two side clamps; the side clamp fixing rod is provided with external threads that match the third threaded hole and the fourth threaded hole; the side clamp fixing rod passes through the third threaded hole and the fourth threaded hole.

[0025] On the other hand, the present invention also provides a solderability testing method suitable for BGA devices. Using the aforementioned solderability testing apparatus for BGA devices, the solderability testing method includes the following steps:

[0026] Step S01: Apply flux to the surface of the solder balls or solder bumps of the BGA device to be tested;

[0027] Step S02: Securely clamp the BGA device using a solderability testing device;

[0028] Step S03: Connect the solderability testing device to the solderability tester;

[0029] Step S04: Use the solderability tester to immerse the solder ball or solder bump to be tested into the solder ball at a specified immersion depth. After a certain dwell time, the test is completed.

[0030] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0031] (1) Existing technologies use the built-in fixtures of commercially available solderability testers for testing. However, this type of clamping relies on the metal elasticity of the fixture, which is not suitable for BGA devices with a large size range. It is also difficult to adjust the clamping size (a lot of force must be applied with fingers in a very small space to clamp the device) and it is easy to cause metal fatigue of the fixture and render it unusable. Compared with the existing technology, the present invention provides a solderability testing device with adjustable size, which is designed for the characteristics of different BGA devices with a large size range and the dense distribution of solder balls or solder bumps to be tested on the bottom plane of the package substrate. This device can meet the requirements of the United Industrial Standard IPCJ-STD-002E, stably clamp BGA devices of various sizes to complete solderability tests without contaminating the solder balls or solder bumps to be tested, and ensure the smooth progress of destructive physical analysis and failure analysis.

[0032] (2) By setting the connecting rod to slide and the fixed block, and using the connecting rod to fix the solderability tester, the present invention can adjust the position of the connecting rod at any time for BGA devices of different sizes, so as to ensure that it is perpendicular to the packaging substrate of the BGA device to be tested and is facing the center of gravity and top surface of the BGA device.

[0033] (3) By setting the first and second side clamps into wedge-shaped blocks, the present invention can ensure that the clamp has good clamping performance and can firmly clamp BGA devices. Unlike the clamps in the prior art that rely on the metal elasticity of the clamp end pieces to "spring" and tighten, the two wedge blocks of the present invention are like needle-nose pliers. By using the wedge structure, the inclined surface of the wedge can reduce the vertical component of the force and increase the horizontal component of the force, so as to achieve a tighter clamping with lighter materials.

[0034] (4) By providing a second threaded hole and a first fastening screw on the fixed end of the second side clamp, the present invention can adjust the relative position between the second side clamp and the fixed block, thereby adjusting the distance between the two side clamps, so that it can be used for BGA devices of different sizes.

[0035] (5) By setting a side clamp fixing rod, the present invention can constrain the wedge clamping plates of the first and second side clamps, ensuring that the wedge clamping plates of the two side clamps remain parallel and do not warp outward due to sample compression deformation.

[0036] In this invention, the above-described technical solutions can be combined with each other to achieve more preferred combinations. Other features and advantages of this invention will be set forth in the following description, and some advantages may become apparent from the description or be learned by practicing the invention. The objects and other advantages of this invention can be realized and obtained through the embodiments described and the accompanying drawings, which are particularly pointed out. Attached Figure Description

[0037] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Throughout the drawings, the same reference numerals denote the same parts.

[0038] Figure 1 Schematic diagram of the solderability testing apparatus for BGA devices provided by the present invention Figure 1 ;

[0039] Figure 2 Schematic diagram of the solderability testing apparatus for BGA devices provided by the present invention Figure 2 ;

[0040] Figure 3 Schematic diagram of the solderability testing apparatus for BGA devices provided by the present invention Figure 3 .

[0041] Figure label:

[0042] 1-BGA device packaging substrate; 2-First wedge clamp; 3-Second wedge clamp; 4-First connecting plate; 5-Second connecting plate; 6-Side clamp fixing rod; 7-Fixing block; 8-Slide groove; 9-Inner fastening nut; 10-Outer fastening nut; 11-First fastening screw; 12-Connecting rod; 13-Fastening end; 14-Second fastening screw; 15-Through groove. Detailed Implementation

[0043] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, which constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not intended to limit the scope of the present invention.

[0044] This invention provides a solderability testing apparatus suitable for BGA devices, such as... Figures 1 to 3As shown, the solderability testing device includes a fixture body and a connector; wherein, the fixture body is fixedly connected to the connector; the fixture body includes a fixing block 7 and a first side clamp and a second side clamp arranged in parallel; both the first side clamp and the second side clamp include a clamping end and a fixing end, both of which are connected to the fixing block 7 through their fixing ends; both the first side clamp and the second side clamp are arranged perpendicularly to the fixing block 7; the first side clamp and the second side clamp are used together to clamp BGA devices; the fixing block 7 is arranged perpendicularly to the connector and the two are slidably connected; the connector is used to be fixedly connected to the solderability tester.

[0045] Existing technology uses the built-in fixtures of commercially available solderability testers for testing. However, this type of clamping relies on the metal elasticity of the fixture, which is not suitable for BGA devices with a large size range. It is also difficult to adjust the clamping size (a lot of force must be applied with fingers in a very small space to clamp the device), and it is easy to cause metal fatigue and failure of the fixture. It is also unable to clamp BGA devices with a size of around 15mm×15mm.

[0046] Compared with the prior art, the present invention can stably clamp BGA devices of different sizes through the first side clamp and the second side clamp; it is especially suitable for clamping BGA devices with a size of more than 15mm×15mm.

[0047] It should be noted that the fixing block 7 of the present invention is in the shape of a cuboid; a sliding groove 8 is provided inside the fixing block 7 along its length direction; the opening direction of the sliding groove 8 is parallel to both the first side clamp and the second side clamp; the two ends of the connector are a sliding end and a connecting end, respectively; the sliding end of the connector passes through the sliding groove 8 and can slide along the length direction of the sliding groove 8; the connecting end of the connector is fixedly connected to the weldability tester.

[0048] It should be noted that, as Figure 1 As shown, the connector is a connecting rod 12, which connects the fixing block 7 to the solderability tester. The installation direction of the connecting rod 12 is parallel to the first and second side clamps and perpendicular to the BGA device packaging substrate 1. The sliding end of the connecting rod 12 passes through the slide groove 8 and can slide along the length of the slide groove 8. The connecting end of the connecting rod 12 is detachably connected to the solderability tester. When performing a solderability test, the BGA device is first fixed using the first and second side clamps. Then, the position of the sliding end of the connecting rod 12 in the slide groove 8 is adjusted so that the connecting rod 12 is perpendicular to the BGA device packaging substrate 1 to be tested, and the connecting rod 12 is facing the center of gravity and top surface of the BGA device. After the solderability tester connected to the connecting end of the connecting rod 12 completes the counterweight balance, the solderability test is performed.

[0049] Compared with the prior art, the present invention sets the connecting rod 12 to be slidably connected to the fixing block 7, and uses the connecting rod 12 to be fixedly connected to the solderability tester. This allows the position of the connecting rod 12 to be adjusted at any time for BGA devices of different sizes, ensuring that it is perpendicular to the BGA device packaging substrate 1 to be tested and facing the center of gravity and top surface of the BGA device.

[0050] In order to lock the sliding end of the connecting rod 12 after it has moved, the connecting parts are provided with inner fastening nuts 9 and outer fastening nuts 10 on the sliding ends on both sides of the slide groove 8. When it is necessary to move or fix the connecting rod 12, the outer fastening nuts 10 are adjusted so that the sliding end of the connecting rod 12 can slide or lock in the slide groove 8.

[0051] Specifically, on the sliding end of the connecting rod 12, starting from the end position, there are an inner threaded section, a sliding section, and a threaded section in sequence; wherein, the sliding section is embedded in the slide groove 8, the inner fastening nut 9 is provided on the inner threaded section, and the outer fastening nut 10 is provided on the outer threaded section; when it is necessary to adjust the position of the connecting rod 12 in the slide groove 8, the outer fastening nut 10 is loosened, and then the sliding end of the connecting rod 12 is moved; when the sliding end of the connecting rod 12 slides to the set position, the outer fastening nut 10 is tightened, and the sliding end of the connecting rod 12 is fixed, thereby stopping the sliding.

[0052] Compared with the prior art, the present invention, by setting an inner fastening nut 9 and an outer fastening nut 10 on both sides of the sliding end of the connecting rod 12 located in the slide groove 8, can adjust the position of the connecting rod 12 in the slide groove 8 for BGA devices of different sizes, so as to ensure that it is perpendicular to the BGA device packaging substrate 1 to be tested and is directly facing the center of gravity and top surface of the BGA device.

[0053] In order to adjust the spacing between the two clamps so that they can clamp BGA devices of different sizes, the fixed end of the first clamp is fixedly connected to the first end of the fixing block 7; the fixed end of the second clamp is provided with a through groove 15, the opening direction of the through groove 15 is the same as the length direction of the fixing block 7, the second end of the fixing block 7 passes through the through groove 15, and the fixed end of the second clamp is slidably connected to the fixing block 7 through its through groove 15.

[0054] When conducting solderability tests, if it is necessary to adjust the distance between the two clamps to match BGA devices of different sizes, the fixed end of the second clamp is slid along the length of the fixing block 7 to increase or decrease the distance between the first and second clamps, thereby enabling it to stably clamp BGA devices of different sizes.

[0055] It should be noted that the first side clamp of the present invention has a horizontal first threaded hole on its fixed end, and the first end of the fixing block 7 is threadedly connected to the fixed end of the first side clamp; the second side clamp has a vertical second threaded hole on its fixed end, and a first fastening screw 11 is provided in the second threaded hole. Adjusting the first fastening screw 11 adjusts the relative position between the fixed end of the second side clamp and the fixing block 7.

[0056] Specifically, when the first fastening screw 11 is tightened, the fixed end of the second side clamp is locked to the fixed block 7, and the two cannot slide relative to each other; when the first fastening screw 11 is loosened, the fixed end of the second side clamp can slide along the length direction of the fixed block 7, thereby adjusting the distance between the two clamps to suit BGA devices of different sizes. After sliding to the set distance, the first fastening screw 11 is tightened.

[0057] Compared with existing technologies, this invention, by providing a second threaded hole and a first fastening screw 11 on the fixed end of the second side clamp, can adjust the relative position between the second side clamp and the fixing block 7, thereby adjusting the distance between the two side clamps to make it suitable for BGA devices of different sizes. This invention adjusts the clamping size through the first fastening screw 11, rather than solely relying on the elastic clamping of the clamping plate to hold the device. Therefore, it is suitable for a wide range of BGA device sizes, especially for BGA devices with a large size range. Adjusting the clamping size with the first fastening screw 11 not only expands the applicability of the clamping device but also allows operators to avoid using excessive force with their fingers in a very small space, and prevents metal fatigue and wear and tear on the clamping device.

[0058] To provide a more stable and secure clamping for BGA devices, the first side clamp of this invention includes a first connecting plate 4 and a first wedge-shaped clamp 2; one end of the first connecting plate 4 is connected to the first wedge-shaped clamp 2, and the other end is fixedly connected to the first end of the fixing block 7; the second side clamp includes a second connecting plate 5 and a second wedge-shaped clamp 3; one end of the second connecting plate 5 is fixedly connected to the second wedge-shaped clamp 3, and the other end is slidably connected to the second end of the fixing block 7; the first connecting plate 4 and the second connecting plate 5 are arranged parallel to each other and have the same structure, and the first wedge-shaped clamp 2 and the second wedge-shaped clamp 3 have the same structure and are arranged parallel to each other.

[0059] Specifically, both the first connecting plate 4 and the second connecting plate 5 are cuboid plates. Along the length of the first connecting plate 4, the first end of the first connecting plate 4 is fixedly connected to the top of the first wedge-shaped clamp 2, and the second end of the first connecting plate 4 (i.e., the fixed end of the first side clamp) is fixedly connected to the fixing block 7. Correspondingly, along the length of the second connecting plate 5, the first end of the second connecting plate 5 is fixedly connected to the top of the second wedge-shaped clamp 3, and the second end of the second connecting plate 5 (i.e., the fixed end of the second side clamp) is slidably connected to the fixing block 7.

[0060] Compared with the prior art, the present invention, by setting the first and second side clamps into wedge-shaped blocks, can ensure that the clamp has good clamping performance and can firmly clamp BGA devices. Unlike the clamps in the prior art that rely on the metal elasticity of the clamp end pieces to "spring" together, the two wedge blocks of the present invention are like needle-nose pliers. By using the wedge-shaped structure, the inclined surface of the wedge can reduce the vertical component of the force and increase the horizontal component of the force, achieving a tighter clamping with lighter materials.

[0061] To prevent the first wedge clamp 2 and the second wedge clamp 3 from deforming and warping outward under the pressure, the clamp body of the present invention also includes a side clamp fixing rod 6; the first connecting plate 4 of the first side clamp is provided with a third threaded hole, and the second connecting plate 5 of the second side clamp is provided with a fourth threaded hole, the thread directions of the third threaded hole and the fourth threaded hole are opposite; the length of the side clamp fixing rod 6 is greater than the distance between the two side clamps; the side clamp fixing rod 6 is provided with an external thread that matches the third threaded hole and the fourth threaded hole; the side clamp fixing rod 6 passes through the third threaded hole and the fourth threaded hole.

[0062] Over time, the clamping test device gradually changes from surface contact friction to edge contact friction with the BGA device, resulting in a decrease in its clamping capacity. To avoid this, the present invention incorporates a side clamp fixing rod 6, which constrains the wedge-shaped clamping plates of the first and second side clamps, ensuring that the wedge-shaped clamping plates of both side clamps remain parallel and do not warp outward due to sample compression deformation.

[0063] It should be noted that a fastening end 13 is provided on the connecting end of the connecting rod 12 of the present invention. The fastening end 13 has a cylindrical cavity and a plurality of threaded holes penetrating the cylindrical cavity. A second fastening screw 14 is correspondingly provided in the threaded hole. By adjusting the second fastening screw 14, the fastening end 13 can be detachably connected to the load-bearing rod of the solderability tester, thereby realizing the detachable connection between the connecting rod 12 and the solderability tester, which facilitates the subsequent operation of the solderability tester to perform solderability tests on BGA devices.

[0064] Specifically, the fastening end 13 of the present invention is provided with a plurality of threaded holes, for example, three threaded holes, each threaded hole being provided with a corresponding second fastening screw 14. By adjusting the three second fastening screws 14 on the fastening end 13, the solderability testing device can be fastened to the load-bearing rod of the solderability tester, and the counterweight balance is completed by the built-in balance of the solderability tester. The solder ball or solder bump to be tested is immersed into the solder ball at a specified immersion depth at an immersion speed of 1mm / s-5mm / s.

[0065] In summary, this invention, by setting a side clamp fixing rod 6 and a reverse threaded connection between the side clamp fixing rod 6 and the first connecting plate 4 and the second connecting plate 5, setting an outer fastening nut 10 on the sliding end of the connecting rod 12, and setting a first fastening screw 11 on the second connecting plate 5, can adjust the clamping size between the first side clamp and the second side clamp, instead of relying solely on the elastic clamping of the clamping plates to hold the device. Therefore, the weldability testing device of this invention has a wide range of applicability. In addition, adjusting the clamping size by using the side clamp fixing rod 6, the first fastening screw 11, and the outer fastening nut 10 not only expands the scope of application, but also makes it convenient for operators to avoid having to use a lot of force with their fingers in a very small space, and also prevents the clamp metal from fatigued and becoming unusable.

[0066] This invention provides a method for testing the solderability of BGA devices, using the aforementioned solderability testing apparatus. The method includes the following steps:

[0067] Step S01: Apply flux to the surface of the BGA solder balls or solder bumps to be tested;

[0068] In step S01 above, flux is applied to the surface of the BGA solder balls or solder bumps to be tested using a clean cotton swab. After application, clean filter paper is used to contact the lowest point of the surface of the BGA solder balls or solder bumps to absorb excess flux, ensuring that no excess flux drips onto the BGA device. This ensures that the surface of the BGA solder balls or solder bumps is completely coated with flux while preventing flux from overflowing.

[0069] In step S01 above, the purpose of applying flux is to serve as an auxiliary material for soldering tests when BGA components are being soldered or when BGA components are being soldered. It is mainly used to remove oxides and oil stains from the surface of the solder or the base material being soldered, prevent oxidation of the base material during the soldering heating process, reduce the surface tension of the molten solder, and assist in heat conduction.

[0070] In step S01 above, the purpose of contacting the lowest point of the BGA solder ball or solder bump surface with clean filter paper to absorb excess flux is to reduce the interference of flux on the solder composition.

[0071] Step S02: Securely clamp the BGA device using a solderability testing device;

[0072] In step S02 above, the distance between the first and second side clamps is first adjusted to match the size of the BGA device to be tested. The process of adjusting the distance between the two side clamps is as follows: loosen the first fastening screw 11 to release the constraint of the first fastening screw 11 on the fixed end of the second side clamp, so that the fixed end of the second side clamp can slide relative to the fixed block 7; at this time, rotate the side clamp fixing rod 6. Since the thread direction of the third threaded hole on the first side clamp is opposite to that of the fourth threaded hole on the second side clamp, the distance between the two side clamps can be increased or decreased while the side clamp fixing rod 6 is turned until the two side clamps can stably clamp the BGA device. At this time, tighten the first fastening screw 11; after fixing the BGA device to be tested, adjust the position of the connecting rod 12, loosen the outer fastening nut 10, and move the position of the sliding end of the connecting rod 12 in the slide groove 8 until the connecting rod 12 is perpendicular to the packaging substrate 1 of the BGA device to be tested and is directly facing the center of gravity and top surface of the BGA device.

[0073] It should be noted that in step S02 above, for BGA devices with solder balls or solder bumps spacing less than 1.75mm, an auxiliary tool (e.g., blade, diagonal pliers, file) is used to cut off a piece of the substrate bottom with individual solder balls or solder bumps, and this piece is used as the BGA device for clamping in step S02. The advantage of this is that it does not damage the solder balls, is easier to clamp than isolated solder balls, and avoids mutual interference when the solder ball spacing is too small during the test.

[0074] It should be noted that the size of the substrate bottom fragments with individual solder balls or solder bumps is less than 15mm × 15mm.

[0075] Step S03: Connect the weldability testing device to the weldability tester via its connecting rod 12;

[0076] In step S03 above, the load-bearing rod of the weldability tester is inserted into the cylindrical cavity of the fastening end 13 on the connecting rod 12. At this time, the three second fastening screws 14 on the fastening end 13 are tightened to fix the connecting rod 12 to the load-bearing rod, thereby fastening the weldability test device to the load-bearing rod of the weldability tester, and using the built-in balance of the weldability tester to complete the counterweight balance.

[0077] Step S04: Operate the solderability tester to immerse the solder ball or solder bump to be tested into the solder ball at an immersion speed of 1mm / s-5mm / s and a specified immersion depth, with a dwell time of 5s, to complete the test.

[0078] It should be noted that after the solderability test is completed, the acceptance or rejection criteria in the IPC standard or the product specification requirements shall be used for judgment (analysis), or the judgment shall be made according to the user's personalized requirements.

[0079] Example 1

[0080] Using a Texas Instruments TMS320C6713BZDPA200 BGA circuit as Example 1 of this invention, its size exceeds 15mm × 15mm; its solderability test method includes the following steps:

[0081] Step S01: Apply flux to the surface of the BGA solder balls or solder bumps to be tested using a clean cotton swab; after application, use clean filter paper to touch the lowest point of the BGA solder balls or solder bumps to absorb excess flux, so that no excess flux drips onto the BGA device.

[0082] Step S02: Securely clamp the BGA device using a solderability testing device;

[0083] Specifically, the process includes: first, adjusting the distance between the first and second side clamps to match the size of the BGA device to be tested. The process of adjusting the distance between the two side clamps is as follows: loosen the first fastening screw 11 to release the constraint of the first fastening screw 11 on the fixed end of the second side clamp, so that the fixed end of the second side clamp can slide relative to the fixed block 7; at this time, rotate the side clamp fixing rod 6. Since the thread direction of the third threaded hole on the first side clamp is opposite to that of the fourth threaded hole on the second side clamp, the distance between the two side clamps can be increased or decreased while the side clamp fixing rod 6 is turned until the two side clamps can stably clamp the BGA device. At this time, tighten the first fastening screw 11; after fixing the BGA device to be tested, adjust the position of the connecting rod 12, loosen the outer fastening nut 10, and move the sliding end of the connecting rod 12 in the slide groove 8 until the connecting rod 12 is perpendicular to the packaging substrate 1 of the BGA device to be tested and directly facing the center of gravity and top surface of the BGA device.

[0084] Step S03: Connect the weldability testing device to the weldability tester via its connecting rod 12;

[0085] Specifically, this includes: inserting the load-bearing rod of the weldability tester into the cylindrical cavity of the fastening end 13 on the connecting rod 12; then, tightening the three second fastening screws 14 on the fastening end 13 to fix the connecting rod 12 to the load-bearing rod, thereby fastening the weldability test device to the load-bearing rod of the weldability tester, and using the built-in balance of the weldability tester to complete the counterweight balance.

[0086] Step S04: Operate the solderability tester to immerse the solder ball or solder bump to be tested into the solder ball at an immersion speed of 3 mm / s and a specified immersion depth, with a dwell time of 5 seconds, to complete the test.

[0087] Example 2

[0088] Example 2 of this invention uses a Xilinx XC7A100T-2CSG324I BGA circuit as an example. This is a BGA device with a solder ball pitch of less than 1.75mm to be tested. The solderability test method includes the following steps:

[0089] Step S01: Apply flux to the surface of the BGA solder balls or solder bumps to be tested using a clean cotton swab; after application, use clean filter paper to touch the lowest point of the BGA solder balls or solder bumps to absorb excess flux, so that no excess flux drips onto the BGA device.

[0090] Step S02: Since the spacing between the solder balls or solder bumps to be tested is less than 1.75mm, use auxiliary tools (e.g., blade, diagonal pliers, file) to cut off the bottom fragment of the substrate with individual solder balls or solder bumps, and use it as a clamping operation for the BGA device; the clamping process includes: first, adjusting the spacing between the first side clamp and the second side clamp so that the spacing matches the size of the BGA device to be tested. The process of adjusting the spacing between the two side clamps is as follows: loosen the first fastening screw 11 to release the constraint of the first fastening screw 11 on the fixed end of the second side clamp, so that the fixed end of the second side clamp can slide relative to the fixing block 7; at this time, rotate The side clamp fixing rod 6 has a thread direction opposite to that of the third threaded hole on the first side clamp and the fourth threaded hole on the second side clamp. Therefore, while turning the side clamp fixing rod 6, the distance between the two side clamps can be increased or decreased until the two side clamps can stably hold the BGA device. At this time, tighten the first fastening screw 11. After fixing the BGA device to be tested, adjust the position of the connecting rod 12, loosen the outer fastening nut 10, and move the sliding end of the connecting rod 12 in the slide groove 8 until the connecting rod 12 is perpendicular to the packaging substrate 1 of the BGA device to be tested and is directly facing the center of gravity and top surface of the BGA device.

[0091] Step S03: Connect the weldability testing device to the weldability tester via its connecting rod 12;

[0092] Specifically, this includes: inserting the load-bearing rod of the weldability tester into the cylindrical cavity of the fastening end 13 on the connecting rod 12; then, tightening the three second fastening screws 14 on the fastening end 13 to fix the connecting rod 12 to the load-bearing rod, thereby fastening the weldability test device to the load-bearing rod of the weldability tester, and using the built-in balance of the weldability tester to complete the counterweight balance.

[0093] Step S04: Operate the solderability tester to immerse the solder ball or solder bump to be tested into the solder ball at an immersion speed of 5 mm / s and a specified immersion depth, with a dwell time of 5 seconds, to complete the test.

[0094] In view of the large size range of different BGA devices and the dense distribution of solder balls or solder bumps to be tested on the bottom plane of the package substrate 1, the present invention overcomes the shortcomings of the prior art and provides a clear and specific solderability testing device and method applicable to BGA devices. It can meet the requirements of the United Industry Standard IPC J-STD-002E, stably clamp BGA devices of various sizes to complete solderability tests without contaminating the solder balls or solder bumps to be tested, and ensure the smooth progress of destructive physical analysis and failure analysis.

[0095] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A solderability testing apparatus suitable for BGA devices, characterized in that, It includes a clamp body and a connector; the clamp body is fixedly connected to the connector; The clamp body includes a fixing block and a first side clamp and a second side clamp arranged in parallel; both the first side clamp and the second side clamp include a clamping end and a fixing end, and both are connected to the fixing block through their respective fixing ends; both the first side clamp and the second side clamp are arranged perpendicularly to the fixing block. The first side clamp and the second side clamp are used together to clamp the BGA device; the fixing block is perpendicular to the connector and the two are slidably connected; the connector is fixedly connected to the solderability tester.

2. The solderability testing apparatus for BGA devices according to claim 1, characterized in that, The fixed block is rectangular in shape; The fixed block has a groove inside it along its length; the opening direction of the groove is parallel to the first side clamp and the second side clamp; the connector includes a sliding end and a connecting end; the sliding end passes through the groove and can slide along the length direction of the groove; the connecting end is used to fix it to the weldability tester.

3. The solderability testing apparatus for BGA devices according to claim 2, characterized in that, An inner fastening nut and an outer fastening nut are respectively provided on the sliding ends located on both sides of the slide groove; When it is necessary to move or fix the connecting rod, adjust the outer fastening nut so that the sliding end of the connecting rod can slide or lock in the groove.

4. The solderability testing apparatus for BGA devices according to claim 3, characterized in that, The fixing end of the first side clamp is fixedly connected to the first end of the fixing block; The fixed end of the second side clamp is provided with a through groove, the opening direction of the through groove is the same as the length direction of the fixed block, the second end of the fixed block passes through the through groove, and the fixed end of the second side clamp is slidably connected to the fixed block through its through groove.

5. The solderability testing apparatus for BGA devices according to claim 4, characterized in that, The first side clamp has a first transverse threaded hole on its fixed end, and the first end of the fixing block is threadedly connected to the fixed end of the first side clamp. The second side clamp has a vertical second threaded hole on its fixed end, and a first fastening screw is provided in the second threaded hole. Adjusting the first fastening screw can adjust the relative position between the fixed end of the second side clamp and the fixed block.

6. The solderability testing apparatus for BGA devices according to claim 1, characterized in that, The first side clamp includes a first connecting plate and a first wedge-shaped clamp, and the second side clamp includes a second connecting plate and a second wedge-shaped clamp.

7. The solderability testing apparatus for BGA devices according to claim 6, characterized in that, One end of the first connecting plate is connected to the first wedge-shaped clamping plate, and the other end is fixedly connected to the first end of the fixing block; One end of the second connecting plate is fixedly connected to the second wedge-shaped clamp, and the other end is slidably connected to the second end of the fixing block.

8. The solderability testing apparatus for BGA devices according to claim 7, characterized in that, The first connecting plate and the second connecting plate are parallel to each other and have the same structure. The first wedge-shaped clamp and the second wedge-shaped clamp have the same structure and are parallel to each other.

9. The solderability testing apparatus for BGA devices according to claim 8, characterized in that, The clamp body also includes a side clamp fixing rod; The first connecting plate of the first side clamp is provided with a third threaded hole, and the second connecting plate of the second side clamp is provided with a fourth threaded hole. The thread directions of the third threaded hole and the fourth threaded hole are opposite. The length of the side clamp fixing rod is greater than the distance between the two side clamps; the side clamp fixing rod is provided with external threads that match the third threaded hole and the fourth threaded hole; the side clamp fixing rod passes through the third threaded hole and the fourth threaded hole.

10. A solderability testing method for BGA devices, characterized in that, The solderability testing apparatus for BGA devices according to any one of claims 1 to 9, the solderability testing method comprising the following steps: Step S01: Apply flux to the surface of the solder balls or solder bumps of the BGA device to be tested; Step S02: Securely clamp the BGA device using a solderability testing device; Step S03: Connect the solderability testing device to the solderability tester; Step S04: Use the solderability tester to immerse the solder ball or solder bump to be tested into the solder ball at a specified immersion depth. After a certain dwell time, the test is completed.

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