Structure convenient for stitch welding of patch device and circuit board

Abstract

The utility model discloses a structure and a circuit board convenient for stitch welding of surface mount devices, comprising a bonding pad, the bonding pad is provided with a solder paste coating area, the solder paste coating area comprises a connection area right above the bonding pad and an expansion area extending out of the bonding pad, the expansion area is located at the second end of the connection area, and the second end of the connection area is connected with the solder paste coating area. And the second end of the connecting region is one end far away from the opposite bonding pad. According to the utility model, by arranging the expansion area, on one hand, enough solder paste is coated, the wetting height of a welding spot is ensured, and the reliability and strength of welding are enhanced; and on the other hand, the layout of the expansion area is adjusted, the possibility of mutual contact of the solder paste in the coating and melting process is reduced, the bridging phenomenon is reduced, and the welding precision and yield are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of patch device stacked soldering, and more specifically, to a structure and a circuit board facilitating the stacked soldering of patch devices. Background Art

[0002] For device stacked soldering, it is required that the bottom device and the top device are interconnected through solder balls. In this process, the amount of solder paste used is crucial. The proper application of solder paste is a prerequisite for ensuring the welding quality. On the one hand, the solder paste provides the necessary conductive and connection functions, and on the other hand, through the solder joints formed after its melting, the mechanical and electrical connection strength between the devices is ensured.

[0003] However, in actual operation, the amount of solder paste used needs to be strictly controlled. If the amount of solder paste is insufficient, it may lead to incomplete solder joints, thereby affecting the reliability and stability of the connection. On the contrary, if the amount of solder paste is excessive, during the reflow soldering process, the excess solder paste is likely to flow and connect with each other, forming a bridge. The bridge affects the insulation between the pads and may also cause a short circuit, seriously affecting the performance and safety of the product.

[0004] The above deficiencies need to be improved. Summary of the Invention

[0005] In order to solve or alleviate the problem of unstable solder joint quality during the stacked soldering of existing devices, the utility model provides a structure and a circuit board facilitating the stacked soldering of patch devices.

[0006] The technical solution of the utility model is described as follows:

[0007] A structure and a circuit board facilitating the stacked soldering of patch devices, including pads, wherein a solder paste coating area is arranged on the pads. The solder paste coating area includes a connection area directly above the pads and an extended area extending outside the pads. The extended area is located at the second end of the connection area, and the second end of the connection area is the end far from the pads.

[0008] Further, a gap is arranged between the first end of the solder paste coating area and the first end of the pads.

[0009] Further, a contraction part is arranged at the first end of the solder paste coating area, and the width of the solder paste coating area at the contraction part is smaller than the widths at other places.

[0010] Further, the width of the contraction part gradually increases from the first end to the second end.

[0011] Further, the extended area includes a first extension part and a second extension part arranged on both sides of the connection area, and the first extension part and the second extension part are symmetrical about the center line in the length direction of the connection area.

[0012] Further, the extension area includes a third extension portion provided at the second end of the connection area.

[0013] Further, a solder paste layer is coated on the solder paste coating area, a first device is provided on the solder paste layer, a second device is provided on the first device, and a soldering aid layer is provided between the first device and the second device.

[0014] Further, the bottom and the periphery of the second device are infiltrated with the soldering aid layer.

[0015] Further, the infiltration height of the soldering aid layer is 0.22 mm to 0.23 mm.

[0016] A circuit board includes the structure for facilitating stacked soldering of patch devices described above.

[0017] According to the present invention of the above solution, the beneficial effects are as follows. By providing the extension area, on the one hand, it ensures sufficient solder paste coating, ensures the wetting height of the solder joints, and enhances the reliability and strength of the welding; on the other hand, it adjusts the layout of the extension area, reduces the possibility of the solder paste contacting each other during the coating and melting processes, reduces the occurrence of bridging phenomena, and improves the welding accuracy and yield. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0019] Figure 1 It is a schematic structural diagram of a solder pad applied to the present invention;

[0020] Figure 2 It is a top view structural diagram of the present invention;

[0021] Figure 3 It is a front view structural diagram of the present invention before welding;

[0022] Figure 4 It is a cross-sectional structural diagram of the present invention after welding.

[0023] Among them, the reference numerals in the drawings: 1, solder pad; 2, solder paste coating area; 201, connection area; 202, contraction portion; 203, extension area; 204, first extension portion; 205, second extension portion; 206, third extension portion; 3, solder paste layer; 4, first device; 5, second device; 6, soldering aid layer; 7, circuit board. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present utility model more clear and understandable, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present utility model and are not used to limit the present utility model.

[0025] It should be noted that when a component is referred to as "fixed" or "arranged" or "connected" to another component, it can be directly or indirectly located on the other component. The orientations or positions indicated by terms such as "upper", "lower", "left", "right", "front", "rear", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientations or positions shown in the drawings, and are only for the convenience of description and cannot be construed as a limitation to the technical solution of the present invention. Terms such as "first", "second", etc. are only for the convenience of description and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of technical features. The meaning of "plurality" is two or more, unless otherwise specifically defined. The meaning of "several" is one or more, unless otherwise specifically defined.

[0026] As Figure 1 and Figure 2 shown, in an embodiment of the present utility model, a structure facilitating the stacked soldering of chip components includes a solder pad 1, on which a solder paste coating area 2 is provided. The solder paste coating area 2 includes a connection area 201 directly above the solder pad 1 and an extended area 203 extending outside the solder pad 1. The extended area 203 is located at the second end of the connection area 201, and the second end of the connection area 201 is the end far from the opposite solder pad 1. The chip components are generally resistors or capacitors, and include two solder pads 1. The two components for stacked soldering have the same package specification but different electrical specifications.

[0027] During production, pads 1 are arranged on the circuit board 7 according to the design requirements. The position, shape, and size of the pads 1 meet the installation requirements of the surface-mounted devices. Using a solder paste printer, an appropriate amount of solder paste is evenly coated on the solder paste coating area 2 on the pads 1. The stencil on the solder paste printer is matched with the circuit board 7, that is, the stencil openings correspond to the solder paste coating area 2, ensuring that the connection area 201 and the extension area 203 are covered with solder paste. The melting point and fluidity of the solder paste are appropriate and compatible with the device material to ensure the welding quality. Place the bottom-layer devices on the solder paste and align the pins with the pads 1. Transfer a certain amount of flux to the bottom of the top-layer devices through a mounter, align the top-layer devices with the bottom-layer devices, and place them on top to ensure stable and accurate stacking of the two layers of devices. Feed the circuit board 7 with the mounted components into a reflow soldering furnace and heat it according to the set temperature curve to melt the solder paste and wet the solder balls and pads 1 to form a reliable electrical connection. Use X-ray inspection equipment to check the solder joint quality to ensure no defects. At the same time, destructive confirmation can also be carried out by methods such as metallographic sectioning to further evaluate the microstructure and performance of the solder joints.

[0028] In this embodiment, by setting the extension area 203, on the one hand, it ensures sufficient solder paste coating, guarantees the wetting height of the solder joints, and enhances the reliability and strength of the welding; on the other hand, the extension areas 203 of the two opposite pads 1 are far from each other, and the layout position of the extension area 203 reduces the possibility of the solder paste contacting each other during the coating and melting processes, reduces the occurrence of bridging phenomena, and improves the welding accuracy and yield.

[0029] As Figure 2 shown, in a preferred example, a gap is provided between the first end of the solder paste coating area 2 and the first end of the pad 1.

[0030] In this embodiment, by providing a gap between the first end of the solder paste coating area 2 and the first end of the pad 1, the distance between the solder paste on the two opposite pads 1 is increased, effectively reducing the chance of the solder paste flowing and contacting each other due to melting during the welding process, reducing the risk of bridging between adjacent pads 1, and improving the welding accuracy and reliability. An appropriate gap enables the solder paste to cover the pads 1 more evenly when melting, forming stable solder joints, ensuring the wettability of the solder joints, thereby ensuring the electrical connection quality and reducing welding defects caused by uneven solder paste distribution.

[0031] As Figure 2 shown, in a preferred example, a constriction 202 is provided at the first end of the solder paste coating area 2, and the width of the solder paste coating area 2 at the constriction 202 is smaller than that at other places.

[0032] The width of the constriction 202 gradually increases from the first end to the second end. That is, a chamfer or a rounded corner is provided at the first end of the solder paste coating area 2 to further reduce the amount of solder paste at the first end of the solder paste coating area 2.

[0033] In this embodiment, the contraction part 202 reduces the width of the solder paste coating area 2 at the first end, thereby reducing the total amount of solder paste in this area. During the soldering process, even if the solder paste melts and flows to a certain extent, due to the smaller amount of solder paste at the first end, the chance of the solder paste between adjacent pads 1 coming into contact with each other is relatively low, effectively preventing the occurrence of bridging. On the other hand, it makes the angle at the corner larger, facilitating the separation of the solder paste from the stencil, ensuring the coating quality and the soldering quality.

[0034] As Figure 2 shown, in a preferred example, the expansion area 203 includes a first extension part 204 and a second extension part 205 arranged on both sides of the connection area 201, and the first extension part 204 and the second extension part 205 are symmetric about the center line in the length direction of the connection area 201.

[0035] The expansion area 203 includes a third extension part 206 arranged at the second end of the connection area 201.

[0036] In this embodiment, the first extension part 204 and the second extension part 205 are symmetric about the center line in the length direction of the connection area 201, so that the forces exerted on the device during the melting process of the solder paste are evenly distributed, preventing the device from shifting due to uneven force and improving the stability and reliability of soldering. At the same time, the symmetric extension parts enable the solder paste to be evenly distributed, enabling the solder paste to stably support the device. During the soldering process, the device is also more likely to remain in the predetermined position, reducing the risk of shifting. During the heating process, the solder paste will climb upward from the first extension part 204, the second extension part 205 and the third extension part 206, ensuring that the pins of the upper device can also be fully wetted, contributing to the formation of a firm and reliable electrical connection and improving the overall performance of the stacked soldering structure.

[0037] As Figure 3 shown, in a preferred example, a solder paste layer 3 is coated on the solder paste coating area 2, a first device 4 is arranged on the solder paste layer 3, a second device 5 is arranged on the first device 4, and a soldering aid layer 6 is arranged between the first device 4 and the second device 5.

[0038] The bottom and the periphery of the second device 5 are infiltrated with the soldering aid layer 6.

[0039] The infiltration height of the soldering aid layer 6 is 0.22 mm to 0.23 mm. The soldering aid layer 6 is a liquid soldering aid, and the second device 5 is immersed into the soldering aid tray by a mounter for infiltration.

[0040] In this embodiment, as Figure 4As shown, the solder mask layer 6 is used to remove the oxides on the surface of the electrodes of the stacked soldering devices and promote the wetting and diffusion of the solder paste during the soldering process. By ensuring sufficient infiltration of the solder mask layer 6 at the bottom and around the second device 5, the infiltration height around is 0.225 mm, and the actual infiltration height can also be 0.22 mm or 0.23 mm, which can effectively improve the cleanliness and wettability of the soldering interface, thereby enhancing the reliability and stability of soldering. The appropriate infiltration height of the solder mask layer 6 helps to form uniform and dense solder joints, which can reduce soldering defects such as dry joints and missed solders, and improve the mechanical strength and electrical performance of the solder joints. At the same time, the presence of the solder mask layer 6 can also suppress the spattering and bubbling phenomena during the soldering process to a certain extent, further improving the soldering quality.

[0041] A circuit board described in an embodiment of the present invention includes the structure for facilitating the stacked soldering of surface-mounted devices as described above.

[0042] In this embodiment, by optimizing the solder paste coating area 2 and the solder mask layer 6, it is possible to ensure the uniform distribution of the solder paste during the soldering process, reduce the occurrence of soldering defects such as dry joints and missed solders, make the solder joints more firm and reliable, reduce circuit failures and malfunctions caused by poor soldering, improve the stability and reliability of the circuit, and extend the service life of the product. At the same time, the presence of the solder mask layer 6 helps to remove the oxides on the surface of the device electrodes, improve the wettability and cleanliness of the soldering interface, and further reduce soldering defects.

[0043] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A structure facilitating the stacked soldering of chip components, characterized in that, It includes a pad, on which a solder paste coating area is provided. The solder paste coating area includes a connection area directly above the pad and an extension area extending outside the pad. The extension area is located at the second end of the connection area, and the second end of the connection area is the end away from the opposite end of the pad.

2. The structure for facilitating the stacked soldering of chip components according to claim 1, wherein A gap is provided between the first end of the solder paste coating area and the first end of the pad.

3. The structure for facilitating the stacked soldering of chip components according to claim 1, wherein, A constriction part is provided at the first end of the solder paste coating area, and the width of the solder paste coating area at the constriction part is smaller than the width at other places.

4. A structure for facilitating the stacked soldering of chip components according to claim 3, characterized in that, The width of the constriction part gradually increases from the first end to the second end.

5. A structure facilitating the stacked soldering of chip components according to claim 1, wherein The extension area includes a first extension part and a second extension part provided on both sides of the connection area, and the first extension part and the second extension part are symmetrical about the center line in the length direction of the connection area.

6. The structure for facilitating the stacked soldering of chip components according to claim 1, wherein The extension area includes a third extension part provided at the second end of the connection area.

7. A structure facilitating the stacked soldering of chip components according to claim 1, wherein The solder paste coating area is coated with a solder paste layer, a first device is provided on the solder paste layer, a second device is provided on the first device, and a soldering aid layer is provided between the first device and the second device.

8. A structure facilitating the stacked soldering of chip components according to claim 7, characterized in that, The bottom and the periphery of the second device are infiltrated with the soldering aid layer.

9. The structure for facilitating the stacked soldering of chip components according to claim 8, characterized in that, The infiltration height of the soldering aid layer is 0.22 mm to 0.23 mm.

10. A circuit board, characterized in that, It includes the structure for facilitating stacked soldering of surface-mounted devices according to any one of claims 1-9.

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