Composite preformed brazing filler metal structure

Abstract

The utility model relates to a composite preformed brazing filler metal structure, and belongs to the technical field of brazing. The composite preformed brazing filler metal structure comprises preformed brazing filler metal and a supporting pad, the preformed brazing filler metal is provided with a groove, the supporting pad is contained in the groove, and the melting point of the supporting pad is larger than that of the preformed brazing filler metal. In the actual application process, welding is conducted at the temperature larger than the melting point of the preformed brazing filler metal and smaller than the melting point of the supporting pad, the preformed brazing filler metal is melted and infiltrates and wraps the supporting pad, so that a welding layer is formed between the first welding face and the second welding face, the supporting pad is not melted, and the effect of supporting the first welding face and the second welding face can be achieved; the first welding face and the second welding face can be prevented from inclining in the welding process, and then the thickness uniformity of the welding layer is improved.

Description

Technical Field

[0001] This utility model relates to the field of brazing technology, and in particular to a composite preformed brazing filler metal structure. Background Technology

[0002] Soft solder is a solder with a liquidus temperature (melting point) not exceeding 450°C. Soft soldering is a connection method that achieves interconnection by heating the soft solder to a temperature lower than the melting point of the workpiece (base material) but higher than the melting point of the soft solder. Soldering is a connection method that fixes two electronic components together by heating the solder to a temperature lower than the melting point of the two electronic components to be connected but higher than the melting point of the solder itself. During service, the solder layer between electronic components is subjected to severe tests such as thermal stress, high-density current, and power cycling. With the increasing precision and integration of electronic components, the requirements for the quality of the solder layer are becoming increasingly stringent. The solder void ratio and thickness uniformity of the solder layer both affect its quality. If the solder void ratio is too high or the thickness uniformity is poor, it will lead to a decrease in the reliability of the solder joint, a deterioration in resistance to thermal cycling and impact, and a higher likelihood of cracks or even breakage in the solder layer, potentially causing irreparable damage to the components.

[0003] Because existing pre-formed solder melts into a fluid state and lacks support capacity, the poor perpendicularity between the pressure direction and the soldering surface of the upper and lower electronic components during the soldering process can cause the solder layer to tilt, resulting in uneven solder layer thickness. In areas with thicker solder layers, the thermal resistance is higher, causing heat generated by the electronic components to accumulate in these areas, leading to localized overheating and potentially causing component failure or burnout. In areas with thinner solder layers, insufficient solder content can lead to voids, increasing the thermal resistance of the solder joint.

[0004] Therefore, it is essential to develop a composite preformed solder structure to reduce the solder void rate of the solder layer, improve the thickness uniformity of the solder layer, and enhance the quality of the solder layer, thereby ensuring the reliable operation of electronic components during service. Utility Model Content

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a composite preformed solder structure.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0007] A composite preformed solder structure includes a preformed solder and a support pad. The preformed solder has a groove adapted to the support pad, and the support pad is accommodated in the groove. The thickness of the preformed solder is H, and the thickness of the support pad is h, where 0.01 mm ≤ Hh ≤ 0.06 mm. The melting point of the support pad is greater than the melting point of the preformed solder.

[0008] Preferably, the difference between the melting point of the support pad and the melting point of the preformed solder is not less than 300°C.

[0009] Preferably, the thermal conductivity of the support pad is higher than that of the preformed solder.

[0010] Preferably, the number of support pads is N, where N is an integer not less than 1.

[0011] Preferably, the melting point of the preformed solder is 100~450℃.

[0012] Preferably, the material of the preformed solder includes any one of tin-based solder, lead-based solder, bismuth-based solder, indium-based solder, antimony-based solder, or zinc-based solder.

[0013] Preferably, the depth of the groove is the same as the thickness of the support pad.

[0014] Preferably, the outer surface of the support pad is provided with a coating, the thickness of which is 0.1~2μm.

[0015] Preferably, the thickness H of the preformed solder is 0.08~0.25mm.

[0016] More preferably, the thickness of the flux coating is 1~60μm.

[0017] Preferably, the distance between the outer wall of the support pad and the inner wall of the groove is no more than 2 mm.

[0018] Compared with the prior art, the beneficial effects of this utility model are as follows:

[0019] This invention provides a support pad within the groove of a pre-formed brazing filler metal. The melting point of the support pad is greater than that of the pre-formed brazing filler metal. In practical applications, welding is performed at a temperature greater than the melting point of the pre-formed brazing filler metal but less than the melting point of the support pad. The pre-formed brazing filler metal melts and impregnates and coats the support pad, thereby forming a weld layer between the first and second welding surfaces. The support pad does not melt and thus supports the first and second welding surfaces, preventing them from tilting during welding and improving the uniformity of the weld layer thickness. Attached Figure Description

[0020] Figure 1 A longitudinal sectional view of a composite preformed solder structure provided in one embodiment of this utility model;

[0021] Figure 2 A schematic diagram of the placement of the pre-formed composite brazing filler metal structure before welding provided in one embodiment of this utility model;

[0022] Figure 3 A longitudinal sectional view of a composite preformed solder structure provided in another embodiment of this utility model;

[0023] Figure 4 A schematic diagram showing the placement of the pre-formed composite brazing filler metal structure before welding, provided for another embodiment of this utility model.

[0024] In the figure, 1 is the composite preformed brazing filler metal structure, 11 is the preformed brazing filler metal, 12 is the groove, 13 is the support pad, 2 is the first part to be welded, 21 is the first welding surface, 3 is the second part to be welded, and 31 is the second welding surface. Detailed Implementation

[0025] To better illustrate the purpose, technical solution, and advantages of this utility model, the following will provide a further description of the utility model in conjunction with specific embodiments.

[0026] Please see Figures 1-4 This utility model provides a composite preformed solder structure 1, including a preformed solder 11 and a support pad 13. The preformed solder 11 is provided with a groove 12 adapted to the support pad 13. The support pad 13 is accommodated in the groove 12. The thickness of the preformed solder 11 is H, and the thickness of the support pad 13 is h, where 0.01mm≤Hh≤0.06mm. The melting point of the support pad 13 is greater than the melting point of the preformed solder 11.

[0027] This invention provides a support pad 13 within the groove 12 of the preformed brazing filler metal 11. Before welding, the composite preformed brazing filler metal structure 1 is placed between the first workpiece 2 and the second workpiece 3 to be welded. One surface of the preformed brazing filler metal 11 in its thickness direction contacts the first welding surface 21 of the first workpiece 2, and the other surface contacts the second welding surface 31 of the second workpiece 3. Since the melting point of the support pad 13 is greater than that of the preformed brazing filler metal 11, when welding is performed at a temperature greater than that of the preformed brazing filler metal 11 but less than that of the support pad 13, the preformed brazing filler metal 11 melts and impregnates and encapsulates the support pad 13, thereby forming a welding layer between the first welding surface 21 and the second welding surface 31. The support pad 13 does not melt and can support the first welding surface 21 and the second welding surface 31, preventing the first welding surface 21 and the second welding surface 31 from tilting during the welding process, thereby improving the thickness uniformity of the welding layer.

[0028] The inventors discovered through research that when Hh meets the above conditions, the thickness uniformity of the formed weld layer is better.

[0029] In one embodiment, the difference between the melting point of the support pad 13 and the melting point of the preformed solder is not less than 300°C.

[0030] In one embodiment, the thermal conductivity of the support pad 13 is higher than that of the preformed solder 11, which not only improves the thermal conductivity of the composite preformed solder during the welding process, but also improves the heat dissipation and resistance to thermal cycling shock of the weld layer formed by the composite preformed solder, thereby helping the weld layer to conduct and dissipate the heat generated when the first and second welded parts are working.

[0031] In one embodiment, the number of support pads 13 is N, where N is an integer not less than 1.

[0032] Specifically, N is an integer of not less than 3, and the N support pads 13 are arranged in an array. For example, if N is 4, the four support pads 13 are distributed at the four corners of the preformed solder 11.

[0033] In one embodiment, the melting point of the preformed solder 11 is 100~450°C.

[0034] In one embodiment, the material of the preformed solder 11 includes at least one of tin-based solder, lead-based solder, bismuth-based solder, indium-based solder, antimony-based solder, or zinc-based solder.

[0035] In one embodiment, the projection of the support pad 13 in its thickness direction is a circle, an ellipse, a polygon, or a shape composed of straight and curved sides.

[0036] In one embodiment, the material of the support pad 13 includes at least one of copper, nickel, silver and palladium.

[0037] In one embodiment, the outer surface of the support pad 13 is provided with a coating (not shown in the figure), the thickness of which is 0.1~2μm.

[0038] Specifically, the material of the plating layer includes at least one of tin, silver, nickel, and gold.

[0039] In one embodiment, the preformed solder 11 has flux coatings (not shown) on two opposing surfaces in its thickness direction.

[0040] Specifically, the thickness of the flux coating is 1~60μm.

[0041] In one embodiment, the distance between the outer wall of the support pad 13 and the inner wall of the groove 12 is no greater than 2 mm. During their research, the inventors discovered that when the distance between the outer wall of the support pad 13 and the inner wall of the groove 12 is within the above range, the pre-formed solder can fully wet and encapsulate the support pad during the welding process.

[0042] In one embodiment, the depth of the groove 12 is the same as the thickness of the support pad 13.

[0043] In one embodiment, the thickness H of the preformed solder 11 is 0.08~0.25 mm.

[0044] It should be understood that this utility model does not involve any improvement to the method. This utility model uses a conventional method to form a groove 12 on the pre-formed solder 11. For example, the groove 12 is a groove formed by stamping on the pre-formed solder 11. Alternatively, a recess is formed by stamping on the pre-formed solder 11, the recess being smaller than the size of the support pad 12. Then, a stamping press is used to align the support pad 12 with the recess and press it into the pre-formed solder 11, thereby forming a groove 12 on the pre-formed solder 11 that matches the contour of the support pad 12.

[0045] It should be understood that in the description of this utility model, the terms "upper" and "lower" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this application.

[0046] It should be understood that in the description of this utility model, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" and "second" may explicitly or implicitly include one or more of that feature.

[0047] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model and are not intended to limit the scope of protection of this utility model. Although this utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of this utility model without departing from the essence and scope of the technical solutions of this utility model.

Claims

1. A composite preform solder structure, characterized by, The device includes a preformed solder and a support pad. The preformed solder has a groove adapted to the support pad, and the support pad is housed in the groove. The thickness of the preformed solder is H, and the thickness of the support pad is h, where 0.01 mm ≤ Hh ≤ 0.06 mm. The melting point of the support pad is greater than the melting point of the preformed solder.

2. The composite preform solder structure of claim 1, wherein, The difference between the melting point of the support pad and the melting point of the preformed solder is not less than 300°C.

3. The composite preform solder structure of claim 1, wherein, The thermal conductivity of the support pad is higher than that of the preformed solder.

4. The composite preform solder structure of claim 1, wherein, The number of support pads is N, where N is an integer not less than 1.

5. The composite preform solder structure of claim 1, wherein, The melting point of the preformed brazing filler metal is 100~450℃.

6. The composite preform solder structure of claim 1, wherein, The depth of the groove is the same as the thickness of the support pad.

7. The composite preform solder structure of claim 1 wherein, The thickness H of the preformed solder is 0.08~0.25mm.

8. The composite preform solder structure of claim 1 wherein, The outer surface of the support pad is provided with a coating, the thickness of which is 0.1~2μm.

9. The composite preform solder structure of claim 1 wherein, The preformed solder has flux coatings on two opposite surfaces in its thickness direction, and the thickness of the flux coatings is 1~60μm.

10. The composite preformed solder structure as described in claim 1, characterized in that, The distance between the outer wall of the support pad and the inner wall of the groove is no greater than 2mm.

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