An axisymmetric solderability fixture apparatus and solderability testing method for a BGA device

Abstract

This invention discloses an axisymmetric solderability fixture device and solderability testing method for BGA devices, belonging to the field of electronic component technology. It solves the problem that existing fixtures rely entirely on the metal elasticity of the fixture for clamping effectiveness, making it impossible to adjust for BGA devices of different sizes, and easily causing metal fatigue and eventual failure. The axisymmetric solderability fixture device includes a fixture body and a connector; the fixture body and the connector are fixedly connected; the fixture body includes a slide rail and a first side clamp and a second side clamp arranged axially symmetrically about the connector; both the first and second side clamps include a clamping end and a fixed end, both slidably connected to the slide rail through their respective fixed ends; the first and second side clamps are used together to clamp the BGA device; the slide rail and the connector are perpendicularly arranged and fixedly connected; the connector is used for fixed connection to a solderability tester. This invention achieves stable clamping of BGA devices, providing support for successful solderability testing.

Description

Technical Field

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

[0002] The main purpose of solderability testing is to detect whether a certain material can obtain 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 with ball grid array or solder ball array. Its external leads are solder balls or solder bumps, which are distributed in an array on the bottom plane of the package substrate. There are generally two principles for solderability testing of BGA devices: reflow soldering simulation principle and wetting weighing principle.

[0003] Existing technologies generally use the built-in fixtures of commercially available solderability testers to conduct tests, which can only hold a very small number of BGAs with small solder ball pitch, and even if they are held, wetting will fail. The built-in fixtures of existing commercially available solderability testers cannot hold them as required by IPC.

[0004] Therefore, existing solderability testing techniques lack a wetting, weighing, and clamping technique suitable for BGA devices. In the industry, the BGA solder balls are often removed and clamped one by one on the instrument's fixture for testing. This practice is prone to damaging the test object (solder ball) during the removal process, and the mechanical damage to the plating can easily interfere with the test results. Moreover, the process is very cumbersome. There is a need to design a clear and specific solderability testing device and method suitable for BGA devices. Summary of the Invention

[0005] Based on the above analysis, the present invention aims to provide an axisymmetric solderability fixture device and solderability testing method for BGA devices, in order to solve the problem that the existing BGA device fixtures are generally fixtures that come with the solderability tester, which are difficult to adjust for the size of the BGA device and are prone to 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 an axisymmetric solderability fixture 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 slide rail and a first side clamp and a second side clamp; the first side clamp and the second side clamp are arranged symmetrically about the connecting member; both the first side clamp and the second side clamp include a clamping end and a fixing end, and both are slidably connected to the slide rail through their respective fixing ends;

[0009] The first and second side clamps are used together to hold BGA devices; the slide rail and the connector are set perpendicularly and fixedly connected; the connector is used to fixally connect to the solderability tester.

[0010] In one possible design, the first side clamp includes a first fixing block and a first clamping plate; the second side clamp includes a second fixing block and a second clamping plate.

[0011] The first clamping plate is fixed to the first fixing block, and the second clamping plate is fixed to the second fixing block. The first fixing block and the second fixing block are arranged parallel to each other and are perpendicular to the slide rail and slidably connected.

[0012] In one possible design, both the first fixing block and the second fixing block are cuboid in shape;

[0013] Both the first and second fixing blocks are provided with through grooves; the slide rail passes through the through grooves.

[0014] In one possible design, a first threaded hole is provided on the end face of the first fixing block away from the first clamping plate, the first threaded hole passes through the corresponding through groove, and a first fastening screw is provided in the first threaded hole;

[0015] The second fixed block has a second threaded hole on the end face away from the second clamping plate. The second threaded hole passes through the corresponding through groove and a second fastening screw is provided in the second threaded hole.

[0016] In one possible design, a first inclined surface is provided on the outer side of the end of the first fixing block adjacent to the first clamping plate, and the fixing end of the first clamping plate is fixed to the first fixing block through the first inclined surface;

[0017] The outer side of the end of the second fixing block adjacent to the second clamping plate is provided with a second inclined surface, and the fixing end of the second clamping plate is fixed to the second fixing block through the second inclined surface;

[0018] The first and second clamping plates are arranged symmetrically in a V-shape.

[0019] In one possible design, both the first clamping plate and the second clamping plate include a fixing part, an arc-shaped part, and a clamping part connected in sequence; both the first clamping plate and the second clamping plate are fixed to their respective inclined surfaces by their fixing parts.

[0020] The clamping portions of the first and second clamping plates are parallel to each other, and both are used together to stably clamp the BGA device.

[0021] In one possible design, the connector is a connecting rod; the first end of the connecting rod is fixedly connected to the slide rail; the second end is connected to the weldability tester.

[0022] In one possible design, the end of the connecting rod connected to the weldability tester is provided with a fastening end; the fastening end is provided with a cylindrical cavity, and multiple threaded holes penetrating the cylindrical cavity are provided on the fastening end, with a third fastening screw corresponding to each threaded hole. The connecting rod is detachably connected to the load-bearing rod of the weldability tester through the fastening end.

[0023] The present invention also provides a method for testing the solderability of BGA devices, using the aforementioned axisymmetric solderability fixture device; the solderability testing method includes the following steps:

[0024] Step S01: Apply flux to the surface of the solder balls or solder bumps of the BGA device to be tested;

[0025] Step S02: Securely clamp the BGA device using an axisymmetric solderable fixture.

[0026] Step S03: Connect the axisymmetric weldability fixture device to the weldability tester;

[0027] 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.

[0028] Furthermore, in step S01, after coating, clean filter paper is used to contact the lowest point of the BGA solder ball or solder bump surface to be tested to absorb excess flux, so that no excess flux drips onto the BGA device.

[0029] Compared with the prior art, the present invention can achieve at least one of the following beneficial effects:

[0030] (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 an axisymmetric solderability fixture device with adjustable size, which is designed for different BGA device sizes and the characteristics of the solder balls or solder bumps to be tested being densely distributed on the bottom plane of the package substrate. This device can meet the requirements of the United Industries 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.

[0031] (2) By fixing the connecting rod to the slide rail, the present invention does not require moving the connecting rod. Only the two clamps on both sides need to be moved to adjust their spacing, so that it can be used for BGA devices of different sizes. It can ensure that the connecting rod is perpendicular to the BGA device packaging substrate to be tested and is directly facing the center of gravity and top surface of the BGA device.

[0032] (3) By setting the first side clamp and the second side clamp as a fixed part, an arc-shaped part and a clamping part, the present invention can ensure that the clamp has good clamping performance while relatively reducing the distance between the two clamping plates, and can firmly clamp small-sized BGA devices.

[0033] (4) The present invention can adjust the spacing between the two clamps by setting a first fastening screw and a second fastening screw at the ends of the first fixing block and the second fixing block, so that it can be used for BGA devices of different sizes.

[0034] 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

[0035] 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.

[0036] Figure 1 This is a schematic diagram of the axisymmetric solderability fixture device for BGA devices according to the present invention. Figure 1 ;

[0037] Figure 2 This is a schematic diagram of the axisymmetric solderability fixture device for BGA devices according to the present invention. Figure 2 ;

[0038] Figure 3 This is a schematic diagram of the axisymmetric solderability fixture device for BGA devices according to the present invention. Figure 3 .

[0039] Figure label:

[0040] 1-First clamping plate; 2-Second clamping plate; 3-Clamping part; 4-Arc-shaped part; 5-Fixing part; 6-First fixing block; 7-Second fixing block; 8-Slide rail; 9-First fastening screw; 10-Second fastening screw; 11-Connecting rod; 12-Fastening end; 13-Third fastening screw. Detailed Implementation

[0041] 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.

[0042] On the one hand, such as Figures 1 to 3 As shown, the present invention provides an axisymmetric solderability fixture for BGA devices. The axisymmetric solderability fixture includes a fixture body and a connector; the fixture body is fixedly connected to the connector; the fixture body includes a slide rail 8 and a first side clamp and a second side clamp; the first side clamp and the second side clamp are arranged axially symmetrically about the connector; both the first side clamp and the second side clamp include a clamping end and a fixing end, and both are slidably connected to the slide rail 8 through their respective fixing ends; the first side clamp and the second side clamp are used together to clamp the BGA device; the slide rail 8 is arranged perpendicularly to the connector and the two are fixedly connected; the connector is used to be fixedly connected to a solderability tester.

[0043] Specifically, the first and second side clamps of the present invention are slidably connected to the slide rail 8. For BGA devices of different sizes, the positions of the first and second side clamps on the slide rail 8 are changed by sliding, thereby adjusting the distance between the first and second side clamps so as to match the specifications of BGA devices of different sizes and achieve the purpose of stably clamping BGA devices of different sizes.

[0044] Existing technology uses the built-in fixture of a commercially available solderability tester for testing. However, this type of clamping relies on the metal elasticity of the fixture, making it difficult to adjust the clamping size (it requires a lot of force to bend the device with your fingers in a very small space). Moreover, it is easy to cause metal fatigue and wear out the fixture, and it is difficult to clamp BGA devices with a size of about 15mm×15mm.

[0045] 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 less than 15mm×15mm.

[0046] To more stably clamp BGA devices, the first side clamp of the present invention includes a first fixing block 6 and a first clamping plate 1; the second side clamp includes a second fixing block 7 and a second clamping plate 2; the first clamping plate 1 is fixed on the first fixing block 6, the second clamping plate 2 is fixed on the second fixing block 7, the first fixing block 6 and the second fixing block 7 are arranged parallel to each other and are both perpendicular to the slide rail 8 and slidably connected.

[0047] Compared with the prior art, the present invention can adjust the distance between the two clamping plates by sliding the first fixing block 6 and the second fixing block 7 to the slide rail 8, so that it can clamp BGA devices of different sizes.

[0048] It should be noted that both the first fixing block 6 and the second fixing block 7 of the present invention are cuboid in shape; both the first fixing block 6 and the second fixing block 7 are provided with through grooves; the slide rail 8 passes through the through grooves.

[0049] Specifically, the slide rail 8 of the present invention is cuboid in shape. The slide rail 8 passes through the through slots of the first fixing block 6 and the second fixing block 7. The slide rail 8 is perpendicular to the first fixing block 6 and the second fixing block 7. When the first fixing block 6 and the second fixing block 7 slide along the length direction of the slide rail 8, they can drive their respective clamping plates to move, thereby changing the distance between the two clamping plates.

[0050] In order to adjust the spacing between the two clamping plates to match BGA devices of different sizes, the first fixing block 6 of the present invention has a first threaded hole on the end face away from the first clamping plate 1, the first threaded hole passes through the corresponding through groove, and a first fastening screw 9 is provided in the first threaded hole; the second fixing block 7 has a second threaded hole on the end face away from the second clamping plate 2, the second threaded hole passes through the corresponding through groove, and a second fastening screw 10 is provided in the second threaded hole.

[0051] Specifically, tightening the first fastening screw 9 locks the first fixing block 6 of the first side clamp to the slide rail 8; similarly, tightening the second fastening screw 10 locks the second fixing block 7 of the second side clamp to the slide rail 8; neither the first side clamp nor the second side clamp can slide relative to the slide rail 8; when the first fastening screw 9 is loosened, the fixing blocks of both the first and second side clamps can slide along the length of the slide rail 8, 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 9 and the second fastening screw 10 are tightened simultaneously.

[0052] It should be noted that since the fixed position of the connecting rod 11 on the slide rail 8 is constant, in order to ensure that it is perpendicular to the BGA device packaging substrate to be tested and directly facing the center of gravity and top surface of the BGA device, when moving the first side clamp and the second side clamp, both need to move towards each other or in opposite directions to ensure that the connecting rod 11 is always in the middle position between the two.

[0053] It should be noted that the outer side of the first fixing block 6 adjacent to the first clamping plate 1 is provided with a first inclined surface, and the fixing end of the first clamping plate 1 is fixed to the first fixing block 6 through the first inclined surface; the outer side of the second fixing block 7 adjacent to the second clamping plate 2 is provided with a second inclined surface, and the fixing end of the second clamping plate 2 is fixed to the second fixing block 7 through the second inclined surface; the first clamping plate 1 and the second clamping plate 2 are arranged symmetrically in a figure-eight shape.

[0054] As the clamping test device is used for a long time, its contact friction with the BGA device gradually changes from surface contact friction to edge contact friction, resulting in a decrease in its clamping ability. To avoid this situation, the present invention provides a first fixing block 6 and a second fixing block 7, which can provide a restraining force for the first clamping plate 1 and the second clamping plate 2, ensuring that the clamping plates of the two clamps remain parallel and do not warp outward due to sample compression deformation.

[0055] In order to clamp BGA devices, especially suitable for clamping BGA devices with a size of less than 15mm×15mm, the first clamping plate 1 and the second clamping plate 2 of the present invention each include a fixing part 5, an arc-shaped part 4 and a clamping part 3 connected in sequence; the first clamping plate 1 and the second clamping plate 2 are fixed to their respective inclined surfaces by their respective fixing parts 5; the clamping parts 3 of the first clamping plate 1 and the second clamping plate 2 are parallel to each other, and both are used together to stably clamp the BGA device.

[0056] Specifically, the fixing part 5, the arc-shaped part 4, and the clamping part 3 of the first side clamp and the second side clamp are connected in sequence. The arc-shaped part 4 is used to realize the smooth connection between each fixing block and its corresponding clamping plate. The two fixing parts 5 are distributed in a figure-eight shape. The distance between the two clamping plates decreases from the fixing part 5 to the clamping part 3, thereby adapting to the clamping of small-sized (smaller than 15mm×15mm) BGA devices.

[0057] It should be noted that the connector of the present invention is a connecting rod 11; the first end of the connecting rod 11 is fixedly connected to the slide rail 8; the second end is connected to the weldability tester; a fastening end 12 is provided on the end of the connecting rod 11 connected to the weldability tester; a cylindrical cavity is provided on the fastening end 12, and a plurality of threaded holes penetrating the cylindrical cavity are provided on the fastening end 12, and a third fastening screw 13 is correspondingly provided in the threaded hole; the connecting rod 11 is detachably connected to the load-bearing rod of the weldability tester through the fastening end 12.

[0058] Specifically, the connecting rod 11 is used to connect the slide rail 8 to the solderability tester. The installation direction of the connecting rod 11 is perpendicular to the BGA device packaging substrate. The first end of the connecting rod 11 passes through the groove of the slide rail 8 and is fixedly connected to the slide rail 8. The second end of the connecting rod 11 is detachably connected to the solderability tester. When performing a solderability test, the BGA device is fixed using the first and second side clamps, so that the connecting rod 11 is perpendicular to the BGA device packaging substrate to be tested, and the connecting rod 11 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 11 completes the counterweight balance, the solderability test is performed.

[0059] It should be noted that the fastening end 12 of the present invention can be detachably connected to the load-bearing rod of the solderability tester, thereby realizing the detachable connection between the connecting rod 11 and the solderability tester, which facilitates the subsequent operation of the solderability tester to perform solderability tests on BGA devices.

[0060] To achieve a fixed connection between the connecting rod 11 and the slide rail 8, the slide rail 8 of the present invention is a cuboid block. At the middle position of the slide rail 8 between the first fixing block 6 and the second fixing block 7, a threaded hole is provided along the thickness direction of the slide rail 8. The first end of the connecting rod 11 passes through the threaded hole. An inner fastening nut and an outer fastening nut are provided on the two sides of the slide rail 8 where the first end of the connecting rod 11 passes through. By simultaneously tightening the inner fastening nut and the outer fastening nut, the first end of the connecting rod 11 is firmly fixed on the slide rail 8.

[0061] On the other hand, the present invention also provides a method for testing the solderability of BGA devices, employing the aforementioned axisymmetric solderability fixture device; the solderability testing method includes the following steps:

[0062] Step S01: Apply flux to the surface of the BGA solder balls or solder bumps to be tested;

[0063] 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.

[0064] 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.

[0065] 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.

[0066] Step S02: Securely hold the BGA device using an axisymmetric solderable fixture.

[0067] In step S02 above, first loosen the first fastening screw 9 and the second fastening screw 10 to release the constraint of the first fastening screw 9 and the second fastening screw 10 on the first side clamp and the second side clamp, so that the first fixing block 6 of the first side clamp and the second fixing block 7 of the second side clamp can move towards or away from each other along the length direction of the slide rail 8, thereby increasing or decreasing the distance between the clamping plates of the two side clamps until the clamping plates of the two side clamps can stably hold the BGA device. At this time, the connecting rod 11 is perpendicular to the packaging substrate of the BGA device to be tested and is directly facing the center of gravity and top surface of the BGA device. Tighten the first fastening screw 9 and the second fastening screw 10, and the first fastening screw 9 and the second fastening screw 10 constrain the corresponding first side clamp and the second side clamp.

[0068] 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.

[0069] It should be noted that the size of the substrate bottom fragments with individual solder balls or solder bumps is less than 15mm × 15mm.

[0070] Step S03: Connect the axisymmetric weldability fixture device to the weldability tester via its connecting rod 11;

[0071] In step S03 above, the load-bearing rod of the weldability tester is inserted into the cylindrical cavity of the fastening end 12 on the connecting rod 11. At this time, the three third fastening screws 13 on the fastening end 12 are tightened to fix the connecting rod 11 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.

[0072] 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.

[0073] 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.

[0074] Example 1

[0075] Using the LTM8063IY#PBF type BGA circuit manufactured by Linear Technology as the BGA device in Embodiment 1 of this invention, its size is less than 15mm × 15mm, and its solderability test method includes the following steps:

[0076] 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 surface of the BGA solder balls or solder bumps to absorb excess flux, so that no excess flux drips onto the BGA device; thus ensuring that the surface of the BGA solder balls or solder bumps is completely coated with flux, and that the flux does not overflow onto the surface.

[0077] Step S02: Securely hold the BGA device using an axisymmetric solderable fixture.

[0078] In step S02 above, first loosen the first fastening screw 9 and the second fastening screw 10 to release the constraint of the first fastening screw 9 and the second fastening screw 10 on the first side clamp and the second side clamp, so that the first fixing block 6 of the first side clamp and the second fixing block 7 of the second side clamp can move towards or away from each other along the length direction of the slide rail 8, thereby increasing or decreasing the distance between the clamping plates of the two side clamps until the clamping plates of the two side clamps can stably hold the BGA device. At this time, the connecting rod 11 is perpendicular to the packaging substrate of the BGA device to be tested and is directly facing the center of gravity and top surface of the BGA device. Tighten the first fastening screw 9 and the second fastening screw 10, and the first fastening screw 9 and the second fastening screw 10 constrain the corresponding first side clamp and the second side clamp.

[0079] Step S03: Connect the axisymmetric weldability fixture device to the weldability tester via its connecting rod 11;

[0080] In step S03 above, the load-bearing rod of the weldability tester is inserted into the cylindrical cavity of the fastening end 12 on the connecting rod 11. At this time, the three third fastening screws 13 on the fastening end 12 are tightened to fix the connecting rod 11 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.

[0081] 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 2 mm / s and a specified immersion depth, with a dwell time of 5 seconds, to complete the test.

[0082] Example 2

[0083] 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:

[0084] Step 1: Apply a very small amount of flux to the surface of the BGA solder ball to be tested using a clean cotton swab. Use a clean filter paper to touch the lowest point of the surface to be tested to absorb excess flux, so that no excess flux drips onto the component.

[0085] Step 2, Step S02: Stably clamp the BGA device using an axisymmetric solderable fixture device;

[0086] In step S02 above, first loosen the first fastening screw 9 and the second fastening screw 10 to release the constraint of the first fastening screw 9 and the second fastening screw 10 on the first side clamp and the second side clamp, so that the first fixing block 6 of the first side clamp and the second fixing block 7 of the second side clamp can move towards or away from each other along the length direction of the slide rail 8, thereby increasing or decreasing the distance between the clamping plates of the two side clamps until the clamping plates of the two side clamps can stably hold the BGA device. At this time, the connecting rod 11 is perpendicular to the packaging substrate of the BGA device to be tested and is directly facing the center of gravity and top surface of the BGA device. Tighten the first fastening screw 9 and the second fastening screw 10, and the first fastening screw 9 and the second fastening screw 10 constrain the corresponding first side clamp and the second side clamp.

[0087] In step S02 above, for BGA devices with solder ball or solder bump spacing less than 1.75mm, a small piece of the substrate bottom with individual solder balls or solder bumps is cut off using an auxiliary tool (e.g., blade, diagonal pliers, file), and used as a clamping device for the BGA device. The size of the small piece of the substrate bottom with individual solder balls or solder bumps is less than 15mm × 15mm.

[0088] Step S03: Connect the axisymmetric weldability fixture device to the weldability tester via its connecting rod 11;

[0089] In step S03 above, the load-bearing rod of the weldability tester is inserted into the cylindrical cavity of the fastening end 12 on the connecting rod 11. At this time, the three third fastening screws 13 on the fastening end 12 are tightened to fix the connecting rod 11 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.

[0090] 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.

[0091] 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. An axisymmetric solderability fixture 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 slide rail and a first side clamp and a second side clamp; the first side clamp and the second side clamp are arranged symmetrically about the connecting member; both the first side clamp and the second side clamp include a clamping end and a fixing end, and both are slidably connected to the slide rail through their respective fixing ends; The first side clamp and the second side clamp are used together to clamp the BGA device; the slide rail is perpendicular to the connector and the two are fixedly connected; the connector is used to be fixedly connected to the solderability tester.

2. The axisymmetric solderability fixture device for BGA devices according to claim 1, characterized in that, The first side clamp includes a first fixing block and a first clamping plate; the second side clamp includes a second fixing block and a second clamping plate; The first clamping plate is fixed on the first fixing block, and the second clamping plate is fixed on the second fixing block. The first fixing block and the second fixing block are arranged parallel to each other and are perpendicular to the slide rail and slidably connected.

3. The axisymmetric solderability fixture device for BGA devices according to claim 2, characterized in that, Both the first fixing block and the second fixing block are cuboid in shape; Both the first fixing block and the second fixing block are provided with through grooves; the slide rail passes through the through grooves.

4. The axisymmetric solderability fixture device for BGA devices according to claim 3, characterized in that, The first fixed block has a first threaded hole on the end face away from the first clamping plate. The first threaded hole passes through the corresponding through groove and a first fastening screw is provided in the first threaded hole. The second fixing block has a second threaded hole on the end face away from the second clamping plate. The second threaded hole passes through the corresponding through groove, and a second fastening screw is provided in the second threaded hole.

5. The axisymmetric solderability fixture device for BGA devices according to claim 4, characterized in that, The outer side of the first fixing block adjacent to the first clamping plate is provided with a first inclined surface, and the fixing end of the first clamping plate is fixed to the first fixing block through the first inclined surface; The outer side of the end of the second fixing block adjacent to the second clamping plate is provided with a second inclined surface, and the fixing end of the second clamping plate is fixed to the second fixing block through the second inclined surface; The first clamping plate and the second clamping plate are arranged symmetrically in a figure-eight shape.

6. The axisymmetric solderability fixture device for BGA devices according to claim 5, characterized in that, Both the first clamping plate and the second clamping plate include a fixing part, an arc-shaped part, and a clamping part connected in sequence; both the first clamping plate and the second clamping plate are fixed to their respective inclined surfaces by their fixing parts. The clamping portions of the first clamping plate and the second clamping plate are parallel to each other, and both are used together to stably clamp the BGA device.

7. The axisymmetric solderability fixture device for BGA devices according to claim 1, characterized in that, The connector is a connecting rod; the first end of the connecting rod is fixedly connected to the slide rail; the second end is connected to the weldability tester.

8. The axisymmetric solderability fixture device for BGA devices according to claim 7, characterized in that, The connecting rod is provided with a fastening end on one end connected to the weldability tester; the fastening end is provided with a cylindrical cavity, and the fastening end is provided with multiple threaded holes penetrating the cylindrical cavity, with a third fastening screw corresponding to each threaded hole; the connecting rod is detachably connected to the load-bearing rod of the weldability tester through the fastening end.

9. A method for testing the solderability of a BGA device, characterized in that, The weldability testing method employs the axisymmetric weldability fixture device according to any one of claims 1 to 8, 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 an axisymmetric solderable fixture. Step S03: Connect the axisymmetric weldability fixture device to the weldability 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.

10. The solderability test method for BGA devices according to claim 9, characterized in that, In step S01, after coating, clean filter paper is used to contact the lowest point of the BGA solder ball or solder bump surface to be tested to absorb excess flux, so that no excess flux drips onto the BGA device.

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