Circuit board structure capable of improving welding yield of heat dissipation bonding pad

Abstract

The utility model discloses a circuit board structure capable of improving the welding yield of a heat dissipation pad, which comprises a circuit board, a device disc used for connecting device pins is arranged on the circuit board, a first steel mesh is arranged on the device disc, the heat dissipation pad is arranged in the middle of the device disc, and a second steel mesh is arranged on the heat dissipation pad. The second steel mesh is distributed on the heat dissipation bonding pad in a multi-point mode, and the first steel mesh and the second steel mesh are consistent in size or the size of the first steel mesh is larger than that of the second steel mesh. According to the utility model, through optimizing the second steel mesh of the heat dissipation pad, the second steel mesh is distributed on the heat dissipation pad in a multi-point manner, the solder paste amount of the heat dissipation pad can be dispersed, the solder paste can be uniformly distributed on the heat dissipation pad, and because the size of the second steel mesh arranged on the heat dissipation pad is approximately consistent with the size of the first steel mesh arranged on the surrounding device disc, the solder paste can be uniformly distributed on the heat dissipation pad. The soldering tin amount of each welding point basically tends to be consistent with the soldering tin amount of the peripheral device disc, the cooling time of soldering tin tends to be consistent, and the soldering tin welding effect is better.

Description

Technical Field

[0001] The utility model relates to the technical field of circuit boards, and more specifically to a circuit board structure capable of improving the welding yield rate of a heat dissipation pad. Background Art

[0002] Printed Circuit Board (PCB), also known as printed circuit board, is an important part of the physical support and signal transmission of electronic products. With the continuous development of electronic technology, the size of electronic products is getting smaller and smaller, and the devices are becoming more and more dense. For the chips of electronic devices, a certain amount of heat will be generated during operation, and the chips have higher and higher requirements for heat dissipation. If the heat dissipation of the device is not good, the service life of the chip will be shortened due to overheating of the device, and even the chip will be damaged. Therefore, most devices will have heat dissipation pads, which can effectively transfer heat from the heat dissipation device to the heat dissipation pad for heat dissipation treatment.

[0003] The traditional heat sink pad has a large area, and a steel mesh of the same size as the heat sink pad is usually designed for welding. Due to the large area of ​​the steel mesh, the pad requires a lot of solder paste, which can easily cause the following problems: Since the steel mesh on the heat sink pad is very large, a lot of solder paste will be applied, and the excess solder paste will accumulate in the middle of the heat sink pad, which will lift up the heat sink pad of the device, causing other pads of the device to have poor welding such as cold soldering and leaking soldering, thereby increasing production costs.

[0004] For example, a Chinese patent with application number 202011007591.7 discloses a design method for a QFN chip heat dissipation pad steel mesh, which uses a steel mesh for array-type block design, leaving a channel covered with solder mask oil in the middle. The gas generated by the flux during welding can be discharged from the channel, reducing poor welding problems caused by obstructed gas discharge.

[0005] However, the steel mesh on the heat sink pad in the middle of the device is much larger than the steel mesh on the ordinary pad around the device (such as Figure 1 As shown in the figure). The steel mesh of the heat dissipation pad is too different from the steel mesh of the surrounding ordinary pads. When soldering, the amount of solder paste applied will be different. The amount of solder paste applied to the middle heat dissipation pad is more than that applied to other ordinary pads, and the solder cooling time is inconsistent. The cooling speed of the solder paste has a certain impact on the welding quality. Too slow a cooling speed may cause the solder joint to be coarse and affect the welding strength; too fast a cooling speed may cause excessive internal stress in the solder joint, affecting the welding reliability. Utility Model Content

[0006] In order to overcome the problems that the existing steel mesh of the heat dissipation pad is too different from the steel mesh of the surrounding ordinary pads, the amount of solder paste brushed will be different during soldering, the amount of solder paste brushed on the middle heat dissipation pad is more than that on other ordinary pads, and the solder cooling time is inconsistent, the utility model provides a circuit board structure that improves the soldering yield of the heat dissipation pad.

[0007] The technical solution of the utility model is as follows:

[0008] A circuit board structure for improving the soldering yield of a heat dissipation pad comprises a circuit board, wherein the circuit board is provided with a device pad for connecting device pins, a first steel mesh is provided on the device pad, a heat dissipation pad is provided in the middle of the device pad, a second steel mesh is provided on the heat dissipation pad, and the second steel mesh is distributed on the heat dissipation pad in a multi-point manner, the first steel mesh is consistent with the second steel mesh in size or the first steel mesh is larger than the second steel mesh, so that the solder cooling time of the first steel mesh and the second steel mesh is relatively consistent.

[0009] According to the above solution of the utility model, the width of the second steel mesh is 0.2 mm, and the length of the second steel mesh is in the range of 0.2-0.5 mm.

[0010] According to the above solution of the utility model, the distance between two adjacent second steel meshes is greater than 0.5 mm.

[0011] According to the utility model of the above solution, the symmetry axis of the second steel mesh has an angle with one side of the heat dissipation pad, and the angle ranges from 15° to 45°.

[0012] According to the above-mentioned solution of the utility model, the size of the second steel mesh located at the edge of the heat dissipation pad is smaller than the size of the second steel mesh located in the middle of the heat dissipation pad.

[0013] According to the above solution of the utility model, the symmetry axis of the second steel mesh is perpendicular to an edge of the heat dissipation pad.

[0014] According to the above solution of the utility model, the sizes of the second steel meshes located in the heat dissipation pad are consistent.

[0015] According to the utility model of the above scheme, a second solder resist window is provided outside the heat dissipation pad, and a first solder resist window is provided outside the device pad.

[0016] The utility model according to the above scheme has the beneficial effect that the utility model optimizes the second steel mesh of the heat dissipation pad so that the second steel mesh is distributed in a multi-point manner on the heat dissipation pad, so that the amount of solder paste on the heat dissipation pad can be dispersed, and the solder paste can be evenly distributed on the heat dissipation pad. Moreover, since the size of the second steel mesh opened on the heat dissipation pad is almost the same as the size of the first steel mesh opened on the surrounding device pad, the amount of solder at each welding point is basically consistent with the amount of solder on the surrounding device pads, and the cooling time of the solder will be consistent, so that the soldering effect is better. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of a structural plate of the prior art;

[0018] Figure 2 This is a schematic structural diagram of the first embodiment of the present utility model;

[0019] Figure 3 This is a schematic structural diagram of the second embodiment of the present utility model.

[0020] In the drawings, the reference numerals are as follows:

[0021] 1. Circuit board; 11. Component plate; 111. First steel mesh; 112. First solder resist window; 12. Heat dissipation pad; 121. Second steel mesh; 122. Second solder resist window. DETAILED DESCRIPTION

[0022] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments.

[0023] It should be noted that the terms "including" and "having" and any variations thereof in the specification and claims of the present utility model are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products or devices. Terms such as "setting" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral body; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. The directions or positions indicated by the terms "upper", "lower", "left", "right", "front", "back", "bottom", etc. are based on the directions or positions shown in the drawings, which are only for the convenience of description and cannot be understood as limitations on the present technical solution.

[0024] It should be noted that the steel mesh on the heat dissipation pad in the middle of the existing device is much larger than the steel mesh on the ordinary pad around the device (such as Figure 1 As shown in the figure). The steel mesh of the heat dissipation pad is too different from the steel mesh of the surrounding ordinary pads. When soldering, the amount of solder paste applied will be different. The amount of solder paste applied to the middle heat dissipation pad is more than that applied to other ordinary pads, and the solder cooling time is inconsistent. The cooling speed of the solder paste has a certain impact on the welding quality. Too slow a cooling speed may cause the solder joint to be coarse and affect the welding strength; too fast a cooling speed may cause excessive internal stress in the solder joint, affecting the welding reliability.

[0025] like Figure 2-Figure 3 As shown, the present embodiment provides a circuit board 1 structure for improving the soldering yield rate of the heat dissipation pad 12. By optimizing the second steel mesh 121 of the heat dissipation pad 12, the second steel mesh 121 is distributed on the heat dissipation pad 12 in a multi-point manner, so that the amount of solder paste of the heat dissipation pad 12 can be dispersed, and the solder paste can be evenly distributed on the heat dissipation pad 12. Moreover, since the size of the second steel mesh 121 opened on the heat dissipation pad 12 is almost the same as the size of the first steel mesh 111 opened on the surrounding device disk 11, the amount of solder at each welding point is basically consistent with the amount of solder on the surrounding device disk 11, and the cooling time of the solder will be consistent, so that the soldering effect is better.

[0026] Specifically, it includes a circuit board 1, on which is provided a device disk 11 for connecting device pins, on which is provided a first steel mesh 111, a heat dissipation pad 12 is provided in the middle of the device disk 11, on which is provided a second steel mesh 121, and the second steel mesh 121 is distributed on the heat dissipation pad 12 in a multi-point manner, and the sizes of the first steel mesh 111 and the second steel mesh 121 are the same or the size of the first steel mesh 111 is larger than the size of the second steel mesh 121, so that the solder cooling time of the first steel mesh 111 and the second steel mesh 121 are relatively consistent.

[0027] The heat dissipation pad 12 adopts a multi-point distributed second steel mesh 121 design, so that the solder paste can be more evenly distributed on the heat dissipation pad 12, avoiding welding problems caused by too much or too little solder paste.

[0028] At the same time, by adjusting the size of the second steel mesh 121 to be the same as or slightly smaller than the first steel mesh 111, we ensure that the solder cooling time of the heat dissipation pad 12 and the device pad 11 is relatively consistent. This can not only improve the welding efficiency, but also ensure the stability and reliability of the welding quality.

[0029] In one embodiment, the width of the second steel mesh 121 is 0.2 mm, which can ensure that the solder paste can pass through the steel mesh smoothly and be evenly distributed on the heat dissipation pad 12, and can effectively prevent the problem of too much or too little solder paste caused by the steel mesh being too wide. The length of the second steel mesh 121 is in the range of 0.2-0.5 mm, which can ensure that the solder paste can form a suitable solder joint during the welding process, which is neither too thick nor too thin, thereby ensuring the strength and stability of the welding.

[0030] In order to ensure that the solder paste on the heat dissipation pad 12 can be evenly distributed, the spacing between two adjacent second steel meshes 121 is greater than 0.5 mm. The setting of this spacing not only avoids the over-dense arrangement between the steel meshes and reduces the problem of uneven distribution of solder paste caused by overlapping steel meshes, but also provides sufficient space for heat dissipation during the welding process, which helps to improve the quality and efficiency of welding.

[0031] In one embodiment, the symmetry axis of the second steel mesh 121 forms an angle with one side of the heat dissipation pad 12, and the angle ranges from 15° to 45°. This angle range can ensure that the solder paste can flow along a suitable angle during the soldering process to form a uniform and stable solder joint. If the angle is too small, the solder paste may not flow smoothly, while if the angle is too large, the solder paste may be too dispersed, affecting the soldering quality.

[0032] The size of the second steel mesh 121 at the edge of the heat dissipation pad 12 is smaller than the size of the second steel mesh 121 at the middle of the heat dissipation pad 12. While ensuring the stability of the solder joint, the accumulation of solder paste at the edge can be reduced, making the welding effect more uniform. By adjusting the size of the second steel mesh 121 at different positions, we can better control the distribution and flow of solder paste and further improve the welding yield rate.

[0033] In one embodiment, the symmetry axis of the second steel mesh 121 is perpendicular to one side of the heat dissipation pad 12. This vertical design not only ensures the symmetry of the steel mesh, but also helps to evenly distribute the solder paste during the soldering process, avoiding the deviation or accumulation of the solder paste. At the same time, the vertical design also simplifies the positioning and alignment steps during the manufacturing process of the circuit board 1, and improves production efficiency.

[0034] The size of the second steel mesh 121 located in the heat dissipation pad 12 is consistent. This design ensures the uniformity of the solder amount between different soldering points, thereby improving the consistency and reliability of soldering. By controlling the size of the second steel mesh 121, we can effectively adjust the solder amount to meet the needs of different heat dissipation pads 12 and devices.

[0035] In one embodiment, a second solder resist window 122 is provided outside the heat dissipation pad 12, and a first solder resist window 112 is provided outside the device pad 11. The function of the solder resist window is to prevent the overflow and contamination of solder paste during the soldering process, and ensure that the solder only covers the required soldering points.

[0036] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements and changes should fall within the scope of protection of the claims attached to the utility model.

[0037] The above is an exemplary description of the utility model patent in conjunction with the accompanying drawings. It is obvious that the implementation of the utility model patent is not limited to the above-mentioned method. As long as various improvements are made by adopting the method concept and technical solution of the utility model patent, or the concept and technical solution of the utility model patent are directly applied to other occasions without improvement, they are all within the protection scope of the utility model.

Claims

1. A circuit board structure for improving the soldering yield of a heat dissipation pad, characterized in that: A circuit board is included, wherein a device disk for connecting device pins is provided on the circuit board, a first steel mesh is provided on the device disk, a heat dissipation pad is provided in the middle of the device disk, a second steel mesh is provided on the heat dissipation pad, and the second steel mesh is distributed on the heat dissipation pad in a multi-point manner, and the size of the first steel mesh is consistent with that of the second steel mesh or the size of the first steel mesh is larger than that of the second steel mesh, so that the solder cooling time of the first steel mesh and the second steel mesh is relatively consistent.

2. A circuit board structure for improving the soldering yield of heat dissipation pads according to claim 1, characterized in that: The width of the second steel mesh is 0.2 mm, and the length of the second steel mesh is in the range of 0.2-0.5 mm.

3. A circuit board structure for improving the soldering yield of heat dissipation pads according to claim 2, characterized in that: The distance between two adjacent second steel meshes is greater than 0.5 mm.

4. A circuit board structure for improving the soldering yield of heat dissipation pads according to claim 2 or 3, characterized in that: The symmetry axis of the second steel mesh forms an angle with one side of the heat dissipation pad, and the angle ranges from 15° to 45°.

5. A circuit board structure for improving the soldering yield of heat dissipation pads according to claim 4, characterized in that: The size of the second steel mesh located at the edge of the heat dissipation pad is smaller than the size of the second steel mesh located in the middle of the heat dissipation pad.

6. A circuit board structure for improving the soldering yield of heat dissipation pads according to claim 2 or 3, characterized in that: The symmetry axis of the second steel mesh is perpendicular to an edge of the heat dissipation pad.

7. A circuit board structure for improving the soldering yield of heat dissipation pads according to claim 6, characterized in that: The second steel meshes located in the heat dissipation pad have the same size.

8. The circuit board structure for improving the soldering yield of the heat dissipation pad according to claim 1, characterized in that: A second solder resist window is disposed outside the heat dissipation pad, and a first solder resist window is disposed outside the device pad.

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