A rework tool and method for complex microwave assembly bond site damage

Abstract

The application discloses a kind of repair tool and method for complex microwave assembly bonding point damage, the repair tool includes: first base, and multiple groups of L-shaped support and linear support;The microwave assembly is installed on multiple linear supports;The linear support is installed on the L-shaped support and the installation height and angle of the linear support are adjustable relative to L-shaped support;The L-shaped support is installed on the first base;The application can realize the economic, efficient rework of complex microwave assembly bonding point damage, and the bonding point is repaired by micro-resistance spot welding to avoid the scrapping of box or chip caused by bonding point damage, reduce the multiple heating in traditional repair process, reduce the repair process, shorten the repair time.

Description

Technical Field

[0001] This invention relates to the field of microwave component assembly and resistance spot welding, and specifically to a repair tooling and method for bond point damage in complex microwave components. Background Technology

[0002] Microwave components are core components of active phased array radars. In recent years, with the development of microwave technology, the functions of microwave components involved in radar systems have become increasingly complex. The assembly process involves multiple steps, including microwave housing, substrate, connectors, beads, SMT soldering, bare chip micro-assembly, gold wire bonding, and sealing. The quality of assembly and soldering directly affects the performance of microwave components and their long-term reliability.

[0003] During the manufacturing process, depending on the product characteristics, multiple welding processes such as reflow soldering, vapor phase soldering, and manual soldering are required, along with multiple cleaning processes, before finally bonding. The more production stages there are, the easier it is to introduce welding debris or damage. When debris or damage is in the bonding area, it will damage the surface coating used for bonding. If this is not addressed, it will lead to problems such as inability to bond or bond detachment during bonding, directly affecting bonding quality and efficiency, and even affecting bonding reliability, causing serious quality problems.

[0004] For general soldering residues, such as organic residues and solder dross, cleaning can effectively resolve the issue. However, for residues or damage that has damaged the gold plating on the bonding surface, such as molten solder splatter contamination, microstrip copper layer oxidation contamination, or plating wear, cleaning is insufficient; the only solution is to scrap the enclosure or replace the chip. This rework process is time-consuming and costly. Replacing the chip requires repeated heating to desolder and resolder it, which reduces product reliability. Currently, there is no ideal method for quickly and reliably repairing complex microwave components with bond point damage. Summary of the Invention

[0005] The purpose of this invention is to solve the problems of long rework cycles and high costs in the current process of repairing complex microwave components with bond point damage.

[0006] To achieve the above objectives, this invention proposes a rework fixture for repairing bond point damage in complex microwave components, comprising:

[0007] The first base, as well as multiple sets of L-shaped brackets and straight brackets;

[0008] The microwave component is mounted on multiple straight brackets; the straight brackets are mounted on the L-shaped brackets and the mounting height and angle of the straight brackets are adjustable relative to the L-shaped brackets; the L-shaped brackets are mounted on a first base;

[0009] The L-shaped bracket includes a first horizontal slide groove and a first vertical slide groove arranged perpendicularly to each other. The straight bracket includes a second horizontal slide groove and a second base arranged perpendicularly to each other. The L-shaped bracket is fastened to the first base through the first horizontal slide groove. The straight bracket is fastened to the L-shaped bracket through the first vertical slide groove and the second base, and the relative height and angle of the two are adjustable. The microwave component is fixed to the straight bracket through the second horizontal slide groove.

[0010] Preferably, the first base is provided with a plurality of first connecting holes arranged in an array, and the L-shaped bracket is fixed on the first base by passing through the first horizontal slide groove and the first connecting holes on the first base from top to bottom and fastening them.

[0011] Preferably, the distance between two adjacent first connecting holes is less than the width of the first horizontal groove of the L-shaped bracket, so that the installation position of the L-shaped bracket is adjustable relative to the first base.

[0012] Preferably, the second base has a second connecting hole, and the second fastener is passed through the first vertical groove and the second connecting hole on the second base in sequence and fastened to fix the straight bracket on the L-shaped bracket to form a "Z" shaped structure.

[0013] Preferably, the length and width of the second base are both greater than the width of the first vertical slide groove, so that the installation angle of the straight bracket is adjustable relative to the L-shaped bracket; the length and width of the second base are both less than the length of the first vertical slide groove, so that the installation height of the straight bracket is adjustable relative to the L-shaped bracket.

[0014] Preferably, a third fastener is used to pass through the second horizontal groove and the corresponding connection hole on the microwave component from bottom to top and tighten it to fix the microwave component on the I-shaped bracket.

[0015] Preferably, the bottom of the first base is provided with track clamping edges on all four sides, and the track clamping edges protrude from the bottom surface of the first base.

[0016] This invention also proposes a rework method for bond point damage in complex microwave components, employing the aforementioned rework tooling, and comprising the following steps:

[0017] S1. Fix the microwave assembly onto the rework fixture;

[0018] S2. Move the rework tooling to a microscope and use it to clean the damaged areas of the bonding points inside the microwave assembly, remove excess material, and use it as a base solder.

[0019] S3. Apply flux to the base weldment;

[0020] S4. Cut the solder, place it at the geometric center of the base component, and uniformly coat the solder with the flux to form an intermediate transition solder;

[0021] S5. Prepare the top layer metal and place it above the geometric center of the intermediate transition solder. The size of the top layer metal is not less than the bond point size.

[0022] S6. Move the entire rework fixture so that the damaged position of the bonding point is directly below the spot welding machine's cutting blade, then start the spot welding machine to weld the top layer metal, intermediate transition solder, and base weldment.

[0023] S7. Remove the entire microwave assembly to complete the repair.

[0024] Specifically, step S1 involves: fastening the L-shaped bracket to the first base, adjusting the height and angle of the straight bracket relative to the L-shaped bracket so that the rework position of the microwave component is horizontal and close to the height of the spot welding machine's cutting blade, and then fastening the straight bracket and the microwave component with the second fastener.

[0025] The thickness of the intermediate transition solder is 25-50 μm, and its area is 40%-60% of the bonding point area. The melting temperature of the intermediate transition solder is lower than the bonding point material's tolerance temperature, and it can simultaneously wet the base solder and the top layer metal in the molten state without producing brittle intermetallic compounds.

[0026] In summary, the rework tooling and method of the present invention can clamp various irregularly shaped microwave boxes, and can rework the bonding points at various positions of the box. By using micro-resistance spot welding to patch the bonding points, the scrapping of the box or chip due to bonding point damage is avoided. This reduces the number of heating steps in the traditional rework process, reduces the rework steps, and shortens the rework time, achieving efficient and reliable rework of bonding point damage in complex microwave components. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the repair tooling for bond point damage of complex microwave components according to the present invention.

[0028] Figure 2 This is a schematic diagram showing the connection of each component of the rework tooling of the present invention;

[0029] Figure 3 This is a schematic diagram illustrating the completion of rework in one embodiment of the present invention;

[0030] Figure 4 This is a flowchart of the repair method for bond point damage in complex microwave components according to the present invention. Detailed Implementation

[0031] The following will be combined with the embodiments of the present invention. Figures 1-4The technical solutions, structural features, objectives and effects achieved in the embodiments of the present invention will be described in detail.

[0032] It should be noted that the accompanying drawings are in a very simplified form and use non-precise proportions. They are only used to facilitate and clarify the purpose of illustrating the embodiments of the present invention, and are not intended to limit the implementation conditions of the present invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportional relationship, or adjustments to the size should still fall within the scope of the technical content disclosed in the present invention, provided that they do not affect the effects and objectives that the present invention can produce.

[0033] It should be noted that, in this invention, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only the expressly listed elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus.

[0034] A repair tooling for bond point damage in complex microwave components, such as Figure 1 As shown, the rework fixture is used to fix the microwave component 4 during rework. The rework fixture includes: a first base 1, and multiple sets of L-shaped brackets 2 and straight brackets 3 installed on the first base 1. The L-shaped brackets 2 are installed on the first base 1, and the straight brackets 3 are respectively installed on each L-shaped bracket 2. The installation height and angle of the straight brackets 3 are adjustable relative to the L-shaped brackets 2.

[0035] The first base 1 is provided with a plurality of arrayed first connecting holes 101 for fixing a plurality of the L-shaped brackets 2; such as Figure 2 As shown, the L-shaped bracket 2 includes a first horizontal slide groove 201 and a first vertical slide groove 202 arranged perpendicularly to each other. A first fastening screw 501 is used to pass through the first horizontal slide groove 201 of the L-shaped bracket 2 and the first connecting hole 101 on the first base 1 from top to bottom and is fastened by the screw cap to fix the L-shaped bracket 2 on the first base 1. The distance between two adjacent first connecting holes 101 is less than the width of the first horizontal slide groove 201 of the L-shaped bracket 2, so the L-shaped bracket 2 can be fixed on the first base 1 at any horizontal angle and position by the first fastening screw 501.

[0036] The straight bracket 3 is fixed to the L-shaped bracket 2 via the first vertical sliding groove 202, specifically, as shown below. Figure 2As shown, the straight bracket 3 includes a second horizontal slide groove 301 and a second base 302 perpendicular to the second horizontal slide groove 301. The second base 302 has a second connecting hole. A second fastening screw 502 is used to pass through the first vertical slide groove 202 of the L-shaped bracket 2 and the second connecting hole on the second base 302 in sequence and is fastened with a screw cap to fix the straight bracket 3 on the L-shaped bracket 2, forming a "Z" shaped structure. The length and width of the second base 302 are both greater than the width of the first vertical slide groove 202, so the straight bracket 3 can be fixed on the L-shaped bracket 2 by rotating at any angle (0 to 180°) relative to the L-shaped bracket 2 with the connecting hole as the center. The length and width of the second base 302 are both less than the length of the first vertical slide groove 202, so the installation height of the straight bracket 3 can be changed relative to the first base 1.

[0037] like Figure 1 and Figure 2 As shown, the third fastening screw 503 is passed from bottom to top through the second horizontal groove 301 of the straight bracket 3 and the corresponding connection hole on the microwave component 4 to fix the microwave component 4 on the straight bracket 3; in order to maintain stability, at least 4 sets of L-shaped brackets 2 and straight brackets 3 are used to fix the microwave component 4, and the installation position of the L-shaped bracket 2 and the installation height and angle of the straight bracket 3 are determined according to the shape of the microwave component 4.

[0038] To ensure that each fastening screw and its corresponding screw cap can effectively fasten the screw, the width of each groove and connecting hole is greater than the diameter of the corresponding fastening screw but less than the diameter of the corresponding screw cap, so that the fastening screw can pass through the groove and connecting hole.

[0039] In this embodiment, the first fastening screw 501, the second fastening screw 502, and the third fastening screw 503 are spring-loaded flat washer combination Phillips head screws; the first base 1, the L-shaped bracket 2, and the straight bracket 3 are made of hard aluminum alloy, which has a certain degree of hardness and can support the microwave component 4.

[0040] Furthermore, the bottom four sides of the first base 1 are also provided with a 2mm wide track clamping edge, which protrudes from the bottom surface of the first base 1, so that the first base 1 can be placed and fixed on the track to realize streamlined rework assembly.

[0041] like Figure 3 As shown, the aforementioned rework fixture for complex microwave component bonding point damage is used to rework microwave component 4, specifically to repair the damage to the bonding point on a bare chip 401 within microwave component 4. Figure 4 As shown, it includes the following steps:

[0042] S1. Fix the microwave component 4 onto the rework fixture;

[0043] Specifically, the L-shaped bracket 2 is fastened to the first base 1, and the height and angle of the straight bracket 3 relative to the L-shaped bracket 2 are adjusted so that the repair position of the microwave component, i.e. the damaged position of the bonding point, is horizontal and close to the height of the spot welding machine blade. Then, the straight bracket 2 and the microwave component 4 are fastened by the second fastening screw 502 and the second fastening screw 503.

[0044] S2. Move the rework tooling to a microscope and use a scalpel to clean the damaged parts of the bonding points in the microwave assembly 4, remove excess material, and use it as the base weldment 402.

[0045] S3. Apply flux to the base weldment 402. In this embodiment, no-clean rosin base is used as flux.

[0046] S4. Prepare intermediate transition solder 403: Cut the solder, place it at the geometric center of the base solder 402, and uniformly coat the flux on the solder to form intermediate transition solder 403. In this embodiment, An80Sn20 is used as intermediate transition solder 403.

[0047] S5. Prepare the top layer metal 404: In this embodiment, a gold strip with a purity of 99.99% and a thickness of 0.0127mm is selected as the top layer metal 404, and the top layer metal is placed above the geometric center of the intermediate transition solder 403; in other embodiments, the size of the top layer metal 404 is not smaller than the bonding point size.

[0048] S6. Move the entire rework fixture so that the damaged position of the bonding point is directly below the spot welding machine's cutting blade, then start the spot welding machine to weld the top layer metal 404, the intermediate transition solder 403, and the base weldment 402.

[0049] Specifically, spot welding is performed twice using a spot welding machine with specific electrodes. The first spot welding is done at low power to position the weld and remove flux. The second spot welding is done at high power to further ensure that the intermediate transition solder 403 under the top metal 404 spreads after welding and to reduce the void rate of the weld.

[0050] In this embodiment, a parallel electrode welding head is selected as the wedge of the spot welding machine. The end face formed by its welding is a concave structure with slightly protruding rounded corners around the perimeter and a flat center. The size of the welding head is at least 10 μm smaller than the size of the top layer metal 404.

[0051] S7. Remove the entire microwave assembly 4 to complete the repair.

[0052] In the above steps, the thickness of the intermediate transition solder 403 should be 25-50 μm, its area should be 40%-60% of the bonding point area, and the melting temperature of the intermediate transition solder 403 should be lower than the bonding point material's tolerance temperature. It should also be able to simultaneously wet the base solder 402 and the top metal 404 in the molten state without producing brittle intermetallic compounds.

[0053] like Figure 4 The image shows the effect after the repair is completed. The top metal 404 is reliably connected to the base solder 402 through the intermediate transition solder 403. Subsequent processes can achieve electrical signal connection between the top metal 404 and the bare chip 401 by bonding to the top metal 404, avoiding the situation where the bare chip 401 cannot be bonded due to damage to the base solder 402 and has to be removed and scrapped.

[0054] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A rework method for bond point damage in complex microwave components, employing a rework fixture for bond point damage in complex microwave components, characterized in that, The rework fixture includes: a first base, and multiple sets of L-shaped brackets and straight brackets; the microwave component is mounted on multiple straight brackets; the straight bracket is mounted on the L-shaped bracket, and the installation height and angle of the straight bracket relative to the L-shaped bracket are adjustable; the L-shaped bracket is mounted on the first base; the L-shaped bracket includes a first horizontal slide groove and a first vertical slide groove arranged perpendicularly to each other, and the straight bracket includes a second horizontal slide groove and a second base arranged perpendicularly to each other; the L-shaped bracket is fastened to the first base through the first horizontal slide groove, and the straight bracket is fastened to the L-shaped bracket through the first vertical slide groove and the second base, and the relative height and angle of the two are adjustable; the microwave component is fixed to the straight bracket through the second horizontal slide groove; the rework method The method includes the following steps: S1, fixing the microwave assembly onto the rework fixture; S2, moving the rework fixture to a microscope and cleaning the damaged areas of the bonding points within the microwave assembly to remove excess material, serving as the base solder; S3, applying flux to the base solder; S4, cutting the solder, placing it at the geometric center of the base solder, and uniformly applying the flux to the solder to form an intermediate transition solder; S5, preparing a top layer metal and placing it above the geometric center of the intermediate transition solder, the size of the top layer metal not less than the bonding point size; S6, moving the entire rework fixture so that the damaged position of the bonding point is directly below the spot welding machine's cutting edge, and starting the spot welding machine to weld the top layer metal, intermediate transition solder, and base solder; S7, removing the entire microwave assembly to complete the rework.

2. The repair method for bond point damage in complex microwave components as described in claim 1, characterized in that, The first base is provided with a plurality of first connection holes arranged in an array. The first fastener is used to pass through the first horizontal slide groove and the first connection holes on the first base from top to bottom and is tightened to fix the L-shaped bracket on the first base.

3. The repair method for bond point damage in complex microwave components as described in claim 2, characterized in that, The spacing between two adjacent first connecting holes is less than the width of the first horizontal groove of the L-shaped bracket, so that the installation position of the L-shaped bracket is adjustable relative to the first base.

4. The repair method for bond point damage in complex microwave components as described in claim 1, characterized in that, The second base has a second connecting hole. The second fastener is passed through the first vertical groove and the second connecting hole on the second base in sequence and fastened to fix the straight bracket on the L-shaped bracket, forming a "Z" shaped structure.

5. A repair method for bond point damage in complex microwave components as described in claim 4, characterized in that, The length and width of the second base are both greater than the width of the first vertical slide groove, so that the installation angle of the straight bracket is adjustable relative to the L-shaped bracket; the length and width of the second base are both less than the length of the first vertical slide groove, so that the installation height of the straight bracket is adjustable relative to the L-shaped bracket.

6. The repair method for bond point damage in complex microwave components as described in claim 1, characterized in that, The microwave component is fixed to the I-shaped bracket by passing a third fastener from bottom to top through the second horizontal slide groove and the corresponding connection hole on the microwave component.

7. A repair method for bond point damage in complex microwave components as described in claim 1, characterized in that, The bottom of the first base is provided with track clamping edges on all four sides, which protrude from the bottom surface of the first base.

8. A repair method for bond point damage in complex microwave components as described in claim 1, characterized in that, Step S1 specifically involves: fastening the L-shaped bracket to the first base, adjusting the height and angle of the straight bracket relative to the L-shaped bracket so that the rework position of the microwave component is horizontal and close to the height of the spot welding machine's cutting blade, and then fastening the straight bracket and the microwave component with the second fastener.

9. A repair method for bond point damage in complex microwave components as described in claim 1, characterized in that, The thickness of the intermediate transition solder is 25-50 μm, and its area is 40%-60% of the bonding point area. The melting temperature of the intermediate transition solder is lower than the bonding point material's tolerance temperature, and it can simultaneously wet the base solder and the top layer metal in the molten state without producing brittle intermetallic compounds.

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