Circuit board

Abstract

According to the circuit board, the boss is arranged on the copper layer, the boss is arranged in the open hole, the boss is exposed above the solder mask layer, so that a grounding pad area is formed, the boss is arranged on the copper layer, and the open hole is filled with the boss, so that a stepped concave area of a grounding pad in the prior art cannot be formed, and the reliability of the circuit board is improved. As the boss is provided with the open hole, and the gap between the boss and the open hole is very small, even if the part, filled in the gap between the open hole and the boss, of the adhesive layer is subjected to thermal expansion and cold contraction in a Reflow link, the contact between most area of the adhesive layer and the boss is not influenced, so that the condition of poor contact between the conductive adhesive and a grounding bonding pad area is avoided, and the reliability of the device is improved. And the grounding impedance of the metal reinforcement is not influenced.

Description

Technical Field

[0001] This application relates to the field of printed circuit board manufacturing technology, and more particularly to a circuit board. Background Technology

[0002] Metal reinforcement grounding pads are typically designed with a copper layer. After the solder mask layer is applied, the thickness of the solder mask layer itself creates a stepped effect on the grounding pad. The conductive adhesive on the metal reinforcement needs to fill the stepped recessed area of ​​the grounding pad. During SMT (Surface Mount Technology, a technology used to mount and fix electronic components on printed circuit boards), the conductive adhesive undergoes reflow (a crucial step in the SMT process, involving heating the components on the PCB to a certain temperature, melting the solder of the components, and forming a strong connection with the grounding pad on the printed circuit board; during reflow, the conductive adhesive undergoes thermal expansion and contraction). After thermal expansion and contraction, the conductive adhesive is prone to shrinkage, resulting in poor contact with the grounding pad and affecting the grounding impedance of the metal reinforcement.

[0003] Therefore, how to avoid poor contact between the conductive adhesive and the grounding pad is a technical problem that needs to be solved by those skilled in the art. Utility Model Content

[0004] This application provides a circuit board to avoid poor contact between conductive adhesive and grounding pads.

[0005] To achieve the above objectives, this utility model provides the following technical solution:

[0006] A circuit board includes a copper layer, a solder mask layer, and a metal reinforcing plate. The solder mask layer is disposed above the copper layer and includes an opening with its axis extending vertically. A boss is provided on the side of the copper layer near the solder mask layer. The opening is used to accommodate the boss and form a grounding pad area. The metal reinforcing plate is disposed above the solder mask layer and has an adhesive layer on the side of the metal reinforcing plate near the solder mask layer. The adhesive layer is pressed along the side near the solder mask layer to fill the gap between the opening and the boss.

[0007] Optionally, in the circuit board described above, when the metal reinforcing plate is pressed along the side near the solder resist layer, the adhesive layer softens and forms a liquid adhesive to fill the gap between the opening and the boss.

[0008] Optionally, in the circuit board described above, the wall of the opening is arc-shaped, and the center of the arc of the opening wall is located in a direction away from the boss.

[0009] Optionally, in the above-mentioned circuit board, the boss is a frustum or a truncated cone, and the upper bottom surface of the boss is disposed away from the adhesive layer, while the lower bottom surface of the boss is disposed close to the adhesive layer.

[0010] Optionally, in the circuit board described above, the height of the boss is 5 to 10 micrometers greater than the depth of the opening.

[0011] Optionally, in the circuit board described above, the solder mask layer includes at least three of the aforementioned openings.

[0012] Optionally, in the circuit board described above, the solder resist layer is formed by curing a solder resist agent, which is applied over the copper layer and forms the opening during the application process.

[0013] Optionally, in the circuit board described above, the solder resist layer is a solder resist film, which covers the copper layer, and the solder resist film is laser-cut, mechanically cut, or chemically etched to form the opening.

[0014] Optionally, the circuit board includes copper paste that fills the interior of the opening to form the boss.

[0015] Optionally, in the circuit board described above, multiple dielectric layers are disposed below the side of the copper layer away from the solder resist layer, and a circuit layer is disposed between adjacent dielectric layers.

[0016] The circuit board provided by this utility model has a boss on the copper layer, which is located inside the opening. The boss is exposed above the solder mask layer, thus forming a grounding pad area. Because the boss is set on the copper layer and fills the opening, the "stepped recessed area of ​​the grounding pad" in the prior art is not formed. The gap between the boss and the opening is very small, so even during the reflow process, the part of the adhesive layer filling the gap between the opening and the boss undergoes thermal expansion and contraction, which will not affect the contact between most of the adhesive layer and the boss. This avoids poor contact between the conductive adhesive and the grounding pad area and will not affect the grounding impedance of the metal reinforcement. Attached Figure Description

[0017] The accompanying drawings, incorporated in and forming part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, those skilled in the art can obtain other drawings based on these drawings without creative effort. One or more embodiments are illustrated by way of example through the corresponding images in the accompanying drawings. These exemplary descriptions do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings represent similar elements. Unless otherwise stated, the figures in the drawings do not constitute a limitation on scale.

[0018] Figure 1 This is a schematic diagram of the circuit board structure in one embodiment of the boss provided in this application.

[0019] Figure 2 This is a schematic diagram of the circuit board structure in another embodiment of the boss provided in this application.

[0020] Explanation of reference numerals in the attached figures:

[0021] Copper layer 100, boss 101, copper paste 102, solder resist layer 200, hole wall 201, metal reinforcing plate 300, adhesive layer 301, dielectric layer 400, circuit layer 500. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0023] The following disclosure provides numerous different embodiments or examples for implementing various structures of this application. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples. Such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, various specific examples of processes and materials are provided in this application; however, those skilled in the art will recognize the applicability of other processes and / or the use of other materials.

[0024] For ease of description, spatial relative terms may be used in the text to describe the relative position or movement of one element or feature relative to another element or feature, as shown in the figure. These relative terms include, for example, "inside," "outside," "middle," "outer," "below," "below," "above," "front," "back," etc. Such spatial relative terms are intended to include different orientations of the device in use or operation, other than those depicted in the figure. For example, if the device in the figure undergoes a positional flip, orientation change, or change of motion, these directional indications will change accordingly. For instance, an element described as "below other elements or features" or "below other elements or features" will subsequently be oriented "above other elements or features" or "above other elements or features." Therefore, the example term "below" can include both upper and lower orientations. The device may be otherwise oriented (rotated 90 degrees or in other directions), and the spatial relative descriptors used in the text will be interpreted accordingly.

[0025] See Figure 1 This application provides a circuit board including a copper layer 100, a solder mask layer 200, and a metal reinforcing plate 300. The solder mask layer 200 is disposed above the copper layer 100 and includes an opening with its axis extending vertically. A boss 101 is provided on the side of the copper layer 100 near the solder mask layer 200. The opening is used to accommodate the boss 101 and form a grounding pad area. The metal reinforcing plate 300 is disposed above the solder mask layer 200 and an adhesive layer 301 is provided on the side of the metal reinforcing plate 300 near the solder mask layer 200. The adhesive layer 301 is pressed along the side near the solder mask layer 200 to fill the gap between the opening and the boss 101.

[0026] Specifically, in the design of this circuit board, a copper layer 100 serves as a conductive substrate, with a solder mask layer 200 placed on top to isolate and protect the circuitry. Openings in the solder mask layer 200 accommodate bosses 101 on the copper layer 100, thus forming a grounding pad area. A metal reinforcing plate 300 is tightly bonded to the solder mask layer 200 via an adhesive layer 301. When subjected to pressure, the adhesive layer 301 fills the minute gaps between the bosses 101 and the openings, ensuring the stability of the conductive connection.

[0027] To further optimize the structure, a small chamfer or texture could be added to the hole wall 201 to increase the friction between the boss 101 and the hole, thereby ensuring the stability of the structure. Alternatively, a small chamfer or rounding could be added to the edge of the hole to reduce stress concentration and friction damage. Furthermore, the shape and size of the boss 101 can be adjusted according to actual needs to adapt to the conductivity and grounding requirements of different application scenarios.

[0028] The circuit board provided by this utility model has a boss 101 on the copper layer 100 and the boss 101 is located inside the opening. The boss 101 is exposed above the solder mask layer 200, thus forming a grounding pad area. Because the boss 101 is provided on the copper layer 100 and the boss 101 fills the opening, the "stepped recessed area of ​​the grounding pad" in the prior art will not be formed. The gap between the boss 101 and the opening is very small, so even in the reflow process, the part of the adhesive layer 301 that fills the gap between the opening and the boss 101 undergoes thermal expansion and contraction, which will not affect the contact between most of the adhesive layer 301 and the boss 101. This avoids poor contact between the conductive adhesive and the grounding pad area and will not affect the grounding impedance of the metal reinforcement.

[0029] To optimize the above technical solution, when the metal reinforcing plate 300 is pressed along the side close to the solder resist layer 200, the adhesive layer 301 softens and forms a liquid adhesive to fill the gap between the opening and the boss 101.

[0030] Specifically, during the bonding of the metal reinforcing plate 300 to the solder resist layer 200, the adhesive layer 301 softens under pressure, forming a liquid adhesive. This liquid form allows the adhesive to more fully fill the gap between the boss 101 and the opening, ensuring a tight conductive connection. As pressure continues to be applied and temperature increases, the liquid adhesive gradually solidifies, forming a stable conductive connection to further prevent poor contact between the conductive adhesive and the grounding pad area.

[0031] In this solution, the liquid adhesive has a stronger filling capacity, which can more effectively eliminate the tiny gaps between the boss 101 and the opening, improving the stability and reliability of the conductive connection. The curing process of the liquid adhesive helps to enhance the overall strength of the structure and improve the impact and vibration resistance of the circuit board.

[0032] Furthermore, to ensure uniform filling and curing of the liquid adhesive, pressure and temperature control techniques can be employed during the bonding process. Simultaneously, the curing time and temperature of adhesive layer 301 can be optimized to ensure good electrical conductivity and mechanical properties.

[0033] To optimize the above technical solution, the hole wall 201 is arc-shaped, and the center of the arc of the hole wall 201 is set in a direction away from the boss 101.

[0034] Specifically, the arc-shaped hole wall 201 design reduces the frictional resistance when the boss 101 is inserted into the opening, while increasing the stability of the structure. This design allows the boss 101 to distribute stress more evenly when subjected to external forces, avoiding structural damage caused by stress concentration.

[0035] Meanwhile, when the hole wall 201 of the opening is arc-shaped, the gap between the boss 101 and the opening is wider at the top and narrower at the bottom. The adhesive layer 301 is squeezed, forming liquid adhesive that enters the gap between the boss 101 and the opening. The amount of adhesive is less at the end of the gap between the boss 101 and the opening closer to the copper layer 100, and more at the end of the gap further away from the copper layer 100. During the reflow process, when the part of the adhesive layer 301 filling the gap between the opening and the boss 101 undergoes thermal expansion and contraction, the amount of retraction at the end with less adhesive will be smaller, thereby further avoiding poor contact between the conductive adhesive and the grounding pad area.

[0036] In this solution, there is a significant difference in the amount of adhesive at both ends of the gap between the boss 101 and the opening. When the part of the gap between the boss 101 and the opening away from the copper layer 100 undergoes thermal expansion and contraction, it may have a large amount of shrinkage. In order to optimize the above technical solution, the boss 101 is a frustum or truncated cone, and the upper bottom surface of the boss 101 is set away from the adhesive layer 301, while the lower bottom surface of the boss 101 is set close to the adhesive layer 301.

[0037] Specifically, the upper bottom surface of the boss 101 has a smaller area, while the lower bottom surface has a larger area. The upper bottom surface is positioned away from the adhesive layer 301, and the lower bottom surface is positioned close to the adhesive layer 301. This makes the side edges between the upper and lower bottom surfaces of the boss 101 and the arc-shaped hole wall 201 of the opening tend to be parallel, thereby reducing the amount of adhesive at the end of the gap between the boss 101 and the opening that is away from the copper layer 100. This makes the amount of adhesive at both ends of the gap between the boss 101 and the opening tend to be consistent, further reducing the impact of the amount of adhesive on the shrinkage of the adhesive layer 301 during thermal expansion and contraction, and further avoiding poor contact between the conductive adhesive and the grounding pad area.

[0038] To optimize the above technical solution, the height of the boss 101 is 5 to 10 micrometers larger than the depth of the opening.

[0039] Specifically, the depth of the opening can be the same as the thickness of the solder mask layer 200. The design that the height of the boss 101 is 5-10 micrometers greater than the depth of the opening ensures that the boss 101 can be fully inserted into the opening, leaving a certain gap for filling the conductive adhesive. At the same time, because the boss 101 is relatively high, the arc-shaped hole wall 201 can guide the liquid adhesive, facilitating the adhesive to enter the aforementioned gap. This design helps to eliminate the problem of insufficient filling or overflow of conductive adhesive caused by insufficient or excessive height of the boss 101.

[0040] It should be noted that the degree to which the adhesive layer 301 enters the gap varies depending on the force applied to the metal reinforcing plate 300. When the height of the boss 101 is greater than the hole depth, the operator can control the adhesive layer 301 so that the volume of adhesive corresponding to the extra height of the boss 101 during extrusion can just fill the gap, preventing the adhesive from being lost during the extrusion process.

[0041] This arrangement improves the filling effect and conductivity of the conductive adhesive, ensuring the stability and reliability of the conductive connection, while reducing the amount of conductive adhesive used, thus lowering production costs and reducing environmental pollution.

[0042] To optimize the above technical solution, the solder mask layer 200 includes at least three openings.

[0043] Specifically, the design of having at least three openings in the solder mask layer 200 increases the number and distribution range of grounding pads, improving the grounding performance and load-bearing capacity of the circuit board. This enhances the grounding performance and stability of the circuit board, reducing the risk of circuit failures and performance degradation caused by poor grounding. Operators can optimize the number, location, and size of the openings according to usage needs to better adapt to the circuit board's usage requirements and performance specifications.

[0044] To optimize the above technical solution, the solder resist layer 200 is formed by curing solder resist, and the solder resist is applied on top of the copper layer 100, and an opening is formed during the application process.

[0045] Specifically, the arc-shaped hole wall 201 is naturally formed during the application of solder resist. The location of the arc-shaped hole wall 201 is the edge of the solder resist coating. The height of the boss 101 can be designed according to the preset thickness of the applied solder resist to further avoid poor contact between the conductive adhesive and the grounding pad area. This arrangement can reduce the production cost and cycle time of the circuit board, and improve the production efficiency and market competitiveness of the circuit board.

[0046] To optimize the above technical solution, the solder resist layer 200 is a solder resist film, which covers the copper layer 100, and the solder resist film is laser-cut, mechanically cut or chemically etched to form an opening.

[0047] Specifically, the design of forming openings through laser cutting, mechanical cutting, or chemical etching can precisely control the shape, size, and position of the openings to improve the accuracy and quality of the openings and ensure the stability and reliability of the conductive connection. At this time, the height of the boss 101 can be designed according to the hole depth of the preset opening to further avoid poor contact between the conductive adhesive and the grounding pad area.

[0048] See Figure 2To optimize the above technical solution, the circuit board includes copper paste 102, which fills the interior of the opening to form a boss 101.

[0049] Specifically, the design of forming the boss 101 by filling the opening with copper paste 102 simplifies the production process and improves production efficiency, while ensuring a good connection between the boss 101 and the copper layer 100. It should be noted that during the production process, after the copper paste 102 fills the inside of the opening, the side of the formed boss 101 away from the copper layer 100 needs to be polished, which increases the production cost of the circuit board. Therefore, this application preferably integrates the boss 101 integrally with the copper layer 100.

[0050] Furthermore, operators can optimize the formulation and filling process of copper paste 102 according to production needs to improve its filling effect and conductivity.

[0051] To optimize the above technical solution, a multilayer dielectric layer 400 is provided below the side of the copper layer 100 away from the solder resist layer 200, and a circuit layer 500 is provided between adjacent dielectric layers 400.

[0052] Specifically, the design of placing multiple dielectric layers 400 and circuit layers 500 beneath the copper layer 100 increases the number of layers and complexity of the circuit board, improving its integration and performance, thereby meeting the requirements of high-performance electronic devices. Operators can optimize the materials, structure, and processes of the dielectric layer 400 and circuit layer 500 according to production needs to improve their performance and lifespan. Simultaneously, adding other functional layers, such as shielding layers and heat dissipation layers, can be considered to further enhance the overall performance of the circuit board.

[0053] It should be noted that the circuit board provided by this utility model can be used in the field of printed circuit board manufacturing technology or other fields. Other fields refer to any field other than printed circuit board manufacturing technology. The above is merely an example and does not limit the application field of the circuit board provided by this utility model.

[0054] It should be understood that the terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “described” as used herein may also include the plural forms. The terms “comprising,” “including,” “containing,” and “having” are inclusive and therefore indicate the presence of the stated features, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, elements, components, and / or combinations thereof. The method steps, processes, and operations described herein are not construed as requiring them to be performed in a particular order described or illustrated unless the order of performance is explicitly indicated. It should also be understood that additional or alternative steps may be used.

[0055] Although terms such as first, second, third, etc., may be used in this document to describe multiple elements, components, regions, layers, and / or segments, these elements, components, regions, layers, and / or segments should not be limited by these terms. These terms may be used only to distinguish one element, component, region, layer, or segment from another. Unless the context clearly indicates otherwise, terms such as "first," "second," and other numerical terms used herein do not imply order or sequence. Therefore, the first element, component, region, layer, or segment discussed below may be referred to as the second element, component, region, layer, or segment without departing from the teachings of the exemplary embodiments.

[0056] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A circuit board, characterized in that, The device includes a copper layer (100), a solder mask layer (200), and a metal reinforcing plate (300). The solder mask layer (200) is disposed above the copper layer (100) and includes an opening with its axis extending vertically. A boss (101) is provided on the side of the copper layer (100) near the solder mask layer (200). The opening is used to accommodate the boss (101) and form a grounding pad area. The metal reinforcing plate (300) is disposed above the solder mask layer (200) and has an adhesive layer (301) on the side of the metal reinforcing plate (300) near the solder mask layer (200). The adhesive layer (301) is pressed along the side near the solder mask layer (200) to fill the gap between the opening and the boss (101).

2. The circuit board according to claim 1, characterized in that, When the metal reinforcing plate (300) is pressed along the side near the solder resist layer (200), the adhesive layer (301) softens and forms a liquid adhesive to fill the gap between the opening and the boss (101).

3. The circuit board according to claim 1, characterized in that, The hole wall (201) of the opening is arc-shaped, and the center of the arc of the hole wall is set in a direction away from the boss (101).

4. The circuit board according to claim 3, characterized in that, The boss (101) is a frustum or a truncated cone, and the upper bottom surface of the boss (101) is disposed away from the adhesive layer (301), while the lower bottom surface of the boss (101) is disposed close to the adhesive layer (301).

5. The circuit board according to claim 4, characterized in that, The height of the boss (101) is 5 to 10 micrometers greater than the depth of the opening.

6. The circuit board according to claim 1, characterized in that, The solder resist layer (200) includes at least three of the openings.

7. The circuit board according to claim 1, characterized in that, The solder resist layer (200) is formed by curing solder resist, which is applied over the copper layer (100) and forms the opening during the application process.

8. The circuit board according to claim 1, characterized in that, The solder resist layer (200) is a solder resist film, which covers the copper layer (100) and is formed by laser cutting, mechanical cutting or chemical etching of the solder resist film to form the opening.

9. The circuit board according to claim 1, characterized in that, The copper paste (102) is used to fill the interior of the opening to form the boss (101).

10. The circuit board according to claim 1, characterized in that, Multiple dielectric layers (400) are disposed below the side of the copper layer (100) away from the solder resist layer (200), and a circuit layer (500) is disposed between adjacent dielectric layers (400).

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