A circuit board connection structure and a multilayer circuit board

Abstract

This utility model relates to circuit board manufacturing processes, and particularly to a circuit board connection structure and a multilayer circuit board. A substrate has solder pads with multiple first connection terminals arranged at intervals within the pads; at least one second connection terminal is provided on the substrate, located to one side of the first connection terminals; a connection assembly includes a connection part and a connector; one side of the connection part is located on the second connection terminal, and the connection part has a third connection terminal; the connector connects the first and third connection terminals. By eliminating solder bridges and placing all the first connection terminals within the solder pads, the oxidation of the PAD edges caused by solder bridges during manufacturing is avoided, which would affect the pull strength and reliability of the gold wire bonding.

Description

Technical Field

[0001] This utility model relates to the manufacturing process of circuit boards, and particularly to a circuit board connection structure and a multilayer circuit board. Background Technology

[0002] Wire bonding is a technique widely used in semiconductor packaging and microelectronics manufacturing to connect the electrodes of a chip to an external lead frame or substrate; in other words, it is a technique for connecting a circuit board to external components.

[0003] In existing technologies, each gold wire is individually bonded to a PAD pad, and each PAD pad typically has an independent ink window to expose it. However, in some PAD pad arrangements, solder mask bridges exist between the pads to isolate them from each ink window.

[0004] During production, ink side etching is unavoidable on PCBs. This is because moisture remains at the ink side etching location during the PCB manufacturing process or the cleaning process after SMT at the client. After being exposed to high temperatures, the moisture vaporizes, causing oxidation at the edge of the bonding pads, which in turn affects the pull strength and reliability of the gold wire bonding. Utility Model Content

[0005] To address the technical problem of "ink side etching causing oxidation of PAD edges, which in turn affects the pull force and reliability of gold wire bonding," this utility model proposes a circuit board connection structure and a multilayer circuit board.

[0006] The objective of this utility model is achieved through the following technical solution:

[0007] In a first aspect, this utility model proposes a circuit board connection structure, comprising:

[0008] A substrate is provided with a soldering pad, and a plurality of first connection terminals are arranged at intervals within the soldering pad; at least one second connection terminal is provided on the substrate, and the second connection terminal is located on one side of the first connection terminal.

[0009] A connecting component includes a connecting part and a connecting member; one side of the connecting part is disposed on a second connecting end, the connecting part is provided with a third connecting end, and the connecting member is connected between the first connecting end and the third connecting end.

[0010] The substrate has solder pads with multiple first connection ends arranged at intervals within each pad. At least one second connection end is also provided on the substrate, located to one side of each of the first connection ends. A connecting assembly includes a connecting portion and a connecting member. One side of the connecting portion is located on the second connection end, and the connecting portion has a third connection end. The connecting member connects the first and third connection ends. By eliminating solder bridges and placing all the first connection ends within the solder pads, the oxidation of the PAD edges during fabrication by solder bridges is avoided, which would affect the pull strength and reliability of the gold wire bonding.

[0011] In some implementations, the distance between the welding pad and the first connection end is at least 0.18 mm.

[0012] In some embodiments, the connector is a gold wire, one end of which is soldered to a first connector, a third connector is provided with a wafer end, and the other end of the gold wire is connected to the wafer end.

[0013] In some implementations, the gold wire is 20 μm.

[0014] In some implementations, a metal layer is provided on the first connection end.

[0015] In some embodiments, the metal layer is a gold-plated layer with a thickness of 3.5 μm or more.

[0016] In some embodiments, a first bend is provided at the first connection end near the edge of the welding pad, and a second bend is provided on the welding pad to accommodate the first bend.

[0017] In some embodiments, the first connection terminal includes a first part and a second part, the first part being connected to the edge of the solder pad, and the second part being completely disposed within the solder pad, wherein the width of the first part is the same as the line width, and the width of the second part is greater than the width of the first part.

[0018] In some implementations, the first portion is 0.18 mm.

[0019] Secondly, this utility model proposes a multilayer circuit board, including a first circuit board, a second circuit board, and a third circuit board arranged sequentially; the second circuit board is provided with a plurality of circuit board connection structures as proposed in any one of the first aspects, and the first circuit board is provided with an ink layer, on which solder pads with openings aligned with the circuit board connection structures are provided.

[0020] The beneficial effects of this utility model's circuit board connection structure and multilayer circuit board are:

[0021] The substrate has a connection area, within which a solder pad is arranged, and multiple first connection ends are spaced apart within the solder pad. At least one second connection end is provided on the substrate, located to one side of the first connection end. A connection assembly includes a connection part and a connector. One side of the connection part is located on the second connection end, and the connection part has a third connection end. The connector connects the first and third connection ends. By eliminating solder bridges and placing all the first connection ends within the solder pads, the oxidation of the PAD edges during fabrication by solder bridges is avoided, which would affect the pull strength and reliability of the gold wire bonding. Attached Figure Description

[0022] Figure 1 This is a structural diagram of a circuit board connection structure according to the present invention;

[0023] Figure 2 for Figure 1 Enlarged view of part a in the image;

[0024] Figure 3 This is a structural diagram of a multilayer circuit board according to the present invention.

[0025] Figure label:

[0026] 1. Substrate; 11. Soldering pad; 111. Second bend; 12. First connecting end; 121. First bend; 122. First portion; 123. Second portion; 13. Second connecting end; 14. Third connecting end;

[0027] 21. Connector; 22. Wafer end; 23. Connecting part;

[0028] 3. First circuit board;

[0029] 4. Second circuit board;

[0030] 5. Third circuit board. Detailed implementation method:

[0031] It should be noted that, in the absence of conflict, the embodiments and technical features in the embodiments of this utility model can be combined with each other. The detailed description in the specific embodiments should be understood as an explanation of the spirit of this utility model and should not be regarded as an improper limitation of this utility model.

[0032] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the specific technical solutions of this utility model will be further described in detail below with reference to the accompanying drawings of the embodiments of this utility model. The following embodiments are used to illustrate this utility model, but are not intended to limit the scope of this utility model.

[0033] In the embodiments 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 as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the embodiments of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0034] Furthermore, in this embodiment of the invention, directional terms such as "upper," "lower," "left," and "right" are defined relative to the positions of the components shown in the accompanying drawings. It should be understood that these directional terms are relative concepts, used for relative description and clarification, and can change accordingly depending on the position of the components in the accompanying drawings.

[0035] In the embodiments of this utility model, unless otherwise explicitly specified and limited, the term "connection" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral part; it can be a direct connection or an indirect connection through an intermediate medium.

[0036] In embodiments of this invention, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0037] In this embodiment of the invention, the terms "exemplary" or "for example" are used to indicate that something is an example, illustration, or description. Any embodiment or design described as "exemplary" or "for example" in this embodiment of the invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the terms "exemplary" or "for example" is intended to present the relevant information in a specific manner.

[0038] Example 1:

[0039] like Figure 1 As shown, this embodiment proposes a circuit board connection structure, including:

[0040] The substrate 1 has a soldering pad 11 and a plurality of first connection terminals 12 arranged at intervals in the soldering pad 11; the substrate 1 has at least one second connection terminal 13, which is located on one side of the first connection terminal 12.

[0041] The connecting component includes a connecting part 23 and a connecting member 21; one side of the connecting part 23 is disposed on the second connecting end 13, and the connecting part 23 is provided with a third connecting end 14, and the connecting member 21 is connected between the first connecting end 12 and the third connecting end 14.

[0042] Specifically, ink undercut is inevitable in the PCB manufacturing process. For example, in some practical embodiments, 0.58mil to 0.90mil of undercut will occur on both sides of an opening with a width of 11.59mil. Residual moisture or chemicals will remain at this location, which can affect the edge of the PAD to some extent. This undercut cannot be avoided in multiple production processes. Therefore, this embodiment provides a solder pad 11 on the substrate 1. The solder pad 11 is an opening in the solder mask layer, so that the circuit part is exposed on the solder mask layer for circuit connection. Multiple first connection terminals 12 are arranged at intervals within the solder mask pad. The first connection terminals 12, i.e., PADs, are used for gold wire bonding. All the first connection terminals 12 are located within the solder pad 11. Since gold wire bonding is used for external connection, gold wire bonding usually does not require solder paste. Therefore, the solder bridge can be eliminated and will not cause short circuit problems between them. The substrate 1 is provided with at least one second connection end 13. The second connection end 13 is generally located on the side of the first connection end 12, that is, on the side of the solder pad, in order to avoid the problem of gold wire instability or easy detachment caused by excessive gold wire length. The second connection end 13 is used for setting, soldering, connecting and other components to perform gold wire bonding.

[0043] A connection component is provided at the second connection end 13. The connection part 23 of the connection component is usually a chip, circuit board, or other circuit or component that cannot be integrated onto the circuit board. It achieves a jumper-like function through gold wire bonding, thereby connecting the substrate 1 and the connection component. The connection part 23 can be vertically connected to the substrate 1 through the second connection end 13 to achieve more flexible circuit changes. A third connection end 14 is provided on the connection part 23 so that the connector 21 is connected between the first connection end 12 and the third connection end 14. The connector 21 is usually a gold wire, but it can also be other circuits. There can be multiple gold wires, and in some more specific cases, two wires are used to improve the connection channel and thus improve the connection stability. The above method can 100% improve the oxidation of the control area in the middle 3 / 5 region of the bonded PAD caused by the vaporization of residual moisture in the ink side etching at high temperature.

[0044] The beneficial effect of this embodiment is that ink undercut is inevitable in the PCB manufacturing process, with an industry standard of a maximum acceptable 1 mil. Ink undercut can lead to residual moisture at the ink-etched sites during PCB cleaning or post-SMT cleaning at the client's site. When the moisture at the undercut sites vaporizes at high temperatures, it can cause oxidation of the bonding pads, thereby affecting the tensile strength and reliability of the wire bonding. In this embodiment, a connection area is provided on the substrate 1, and a solder pad 11 is provided within the connection area. Multiple first connection ends 12 are arranged at intervals within the solder pad 11. At least one second connection end 13 is provided on the substrate 1, and the second connection end 13 is located on one side of the first connection end 12. A connection assembly is provided, which includes a connection part 23 and a connector 21. One side of the connection part 23 is located on the second connection end 13, and the connection part 23 is provided with a third connection end 14. The connector 21 connects the first connection end 12 and the third connection end 14. By eliminating the welding bridge and placing all the first connection ends 12 within the welding pad 11, the oxidation of the PAD edge during manufacturing by the welding bridge is avoided, which would affect the pull force and reliability of the gold wire bonding. This replaces the conventional design method, thereby meeting the product's quality requirements and adapting to market and customer needs.

[0045] Example 2:

[0046] Combination such as Figures 1-2 As shown, this embodiment further optimizes and explains the structure proposed in Embodiment 1:

[0047] In some embodiments, the distance between the solder pad 11 and the first connection end 12 is at least 0.18 mm. Specifically, the distance between the solder pad 11 and the first connection end 12 is at least 0.18 mm or 6 mil, to ensure that the ink layer outside the solder pad 11 does not oxidize the first connection end 12 near the edge during circuit board fabrication, thereby affecting the pull force and reliability of the gold wire bonding.

[0048] In some embodiments, the connector 21 is a gold wire, with one end soldered to the first connecting end 12 and the third connecting end 14 having a wafer end 22. The other end of the gold wire is connected to the wafer end 22. Specifically, during gold wire bonding, one end is soldered to the first connecting end 12, specifically to the center, to avoid the impact of edge oxidation on the pull force and reliability of the gold wire bonding. The other end is connected to the wafer end 22, which enables the circuit connection to the connecting part 23. This wafer end 22 improves the stability and reliability of the soldering, making the gold wire bonding suitable for use on higher precision circuit boards.

[0049] In some preferred embodiments, the gold wire is 20µm. Specifically, a gold wire of about 20µm can avoid the gold wire being too long and affecting the stability of the gold wire bonding, and can also avoid the second connection end 13 being too close due to the gold wire being too short, which would cause ink oxidation and affect the connection of the second connection end 13.

[0050] In some embodiments, a metal layer is provided on the first connection end 12. Specifically, a metal layer is generally provided on the first connection end 12, i.e., the PAD, to facilitate the use of gold wire bonding.

[0051] In some preferred embodiments, the metal layer is a gold-plated layer with a thickness of 3.5µm or more. Specifically, the metal layer is a gold layer, i.e., surface gold plating, to facilitate gold wire bonding. The surface gold plating thickness on some precision circuit boards is typically 3.5µm or more, compared to the 1.2µm thickness of ordinary SMT surface-mount gold plating boards. This results in a longer gold plating time for precision circuit boards compared to ordinary surface-mount gold plating boards, and the ink is exposed to the chemicals for a longer period, leading to greater ink side etching. By eliminating the solder pad 11 structure of the solder bridge between the first connection segments, the oxidation of the PAD edges caused by the solder bridge during manufacturing can be avoided, which would affect the pull strength and reliability of the gold wire bonding.

[0052] In some embodiments, a first bend 121 is provided at the first connecting end 12 near the edge of the welding pad 11, and a second bend 111 is provided at the welding pad 11 to accommodate the first bend 121. Specifically, the first bend 121 may be provided at the first connecting end 12 near the welding pad 11, and the first bend 121 may provide a larger area of ​​the first connecting end 12. At the same time, the welding pad 11 may have a window in the second bend 111 to accommodate the first bend 121.

[0053] In some embodiments, the first connection end 12 includes a first portion 122 and a second portion 123. The first portion 122 is connected to the edge of the solder pad 11, and the second portion 123 is completely disposed within the solder pad 11. The width of the first portion 122 is the same as the line width, and the width of the second portion 123 is greater than the width of the first portion 122. Specifically, the first connection end 12 includes a first portion 122 and a second portion 123. The first portion 122 is the portion near the solder pad 11 and is used to connect internal lines outside the solder pad 11 that are covered by the solder resist layer. The second portion 123 is the portion used for gold wire bonding and is typically rectangular. The width of the first portion 122 is the same as the line length of the circuit board. This arrangement reduces the side etching of this portion by the ink, which could affect the oxidation of the PAD edge during manufacturing and thus affect the pull strength and reliability of the gold wire bonding. The second part 123 is wider, and the gold wire is usually welded to the center of the second part 123. The wider second part 123 reduces the impact of ink side etching on the gold wire portion in the center, thereby improving the stability and reliability of the entire first connection end 12.

[0054] In some preferred embodiments, the first portion 122 is 0.18 mm. Specifically, an excessively long first portion 122 would cause excessive exposure of the circuitry to the solder mask layer, resulting in large-area oxidation during use and unstable connections of the entire circuitry. An excessively short first portion 122 would cause the second portion 123 to be too close to the ink layer at the edge of the solder pad 11, resulting in oxidation of the PAD edge and affecting the pull strength and reliability of the gold wire bonding.

[0055] Example 3:

[0056] like Figure 3 As shown, this embodiment proposes a multilayer circuit board, including a first circuit board 3, a second circuit board 4, and a third circuit board 5 arranged sequentially; the second circuit board 4 is provided with a plurality of circuit board connection structures as proposed in any one of Embodiment 1 and / or Embodiment 2, and the first circuit board 3 is provided with an ink layer, on which there are pad openings that are aligned with the circuit board connection structures.

[0057] Specifically, the first circuit board 3 has a solder mask layer to protect most of the circuitry from air, thus preventing oxidation of the circuitry by moisture in the air after prolonged use and causing instability. The first circuit board 3 has openings, which are typically connection terminals for connecting to external circuitry, and also include openings for circuit board connection structures. The solder mask layer is generally an ink layer or other solder mask material. In some more specific embodiments, multiple openings may be included to achieve external connections and gold wire bonding for multiple structures as proposed in Embodiments 1 and / or 2.

[0058] The serial numbers of the utility model embodiments are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments. The above are only preferred embodiments of this utility model and do not limit the patent scope of this utility model. Any equivalent device or equivalent process transformation made based on the content of this utility model specification and drawings, or direct or indirect application in other related technical fields, are similarly included in the patent protection scope of this utility model.

Claims

1. A wiring board connecting structure characterized by comprising: include: A substrate (1) is provided with a soldering pad (11) and a plurality of first connecting ends (12) are arranged at intervals in the soldering pad (11); at least one second connecting end (13) is provided on the substrate (1) and the second connecting end (13) is disposed on one side of the first connecting end (12). The connecting component includes a connecting part (23) and a connecting member (21); one side of the connecting part (23) is disposed on the second connecting end (13), the connecting part (23) is provided with a third connecting end (14), and the connecting member (21) is connected between the first connecting end (12) and the third connecting end (14).

2. The structure according to claim 1, wherein The distance between the welding pad (11) and the first connecting end (12) is at least 0.18 mm.

3. The structure according to claim 1, wherein The connector (21) is a gold wire, one end of which is soldered to the first connector (12), and the third connector (14) is provided with a wafer end (22), and the other end of the gold wire is connected to the wafer end (22).

4. The structure according to claim 3, wherein The gold wire is 20µm.

5. The structure according to claim 1, wherein A metal layer is provided on the first connection end (12).

6. The structure according to claim 5, wherein The metal layer is a gold-plated layer, and the gold plating layer is 3.5 μm or larger.

7. The structure according to claim 1, wherein The first connecting end (12) near the edge of the welding pad (11) is provided with a first bend (121), and the welding pad (11) is provided with a second bend (111), the second bend (111) being accommodated by the first bend (121).

8. The structure of claim 1, wherein The first connection end (12) includes a first part (122) and a second part (123). The first part (122) is connected to the edge of the welding pad (11), and the second part (123) is completely disposed within the welding pad (11). The width of the first part (122) is the same as the line width, and the width of the second part (123) is greater than the width of the first part (122).

9. The structure according to claim 8, wherein The first part (122) is 0.18 mm.

10. A multilayer wiring board, characterized by, The circuit includes a first circuit board (3), a second circuit board (4), and a third circuit board (5) arranged in sequence; the second circuit board (4) is provided with a plurality of circuit board connection structures as described in any one of claims 1-9, and the first circuit board (3) is provided with an ink layer, wherein the ink layer has pad openings that are aligned with the circuit board connection structures.

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