Capacitor and circuit board with capacitor

Abstract

The embodiment of the utility model provides a capacitor and a circuit board with the capacitor. The circuit board comprises a first printed board with a first metal layer, a preset function module arranged on the first printed board, and a preset capacitor, the preset function module comprises a second printed board with a second metal layer; a first pole plate and a second pole plate of the preset capacitor are respectively arranged on a first metal layer and a second metal layer; a preset insulating layer is arranged between the first metal layer and the second metal layer; the preset insulating layer corresponds to areas of the first polar plate and the second polar plate and is used as a dielectric layer of the preset capacitor; and the first polar plate and the second polar plate are respectively connected with preset ports on the circuit board, so that the capacitance function required by the circuit board can be met. Compared with a capacitor in the form of discrete components such as MLCC, the capacitor required by the circuit board is formed by utilizing the structural characteristic that the circuit board has a plurality of metal layers, the cost and size of the capacitor and the circuit board can be controlled, and miniaturization and high integration level of the circuit board are facilitated.

Description

Technical Field

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

[0002] Printed Circuit Boards (PCBs), also known as printed circuit boards, are important components of electronic devices. By forming conductive lines on a carrier board and mounting electronic components such as resistors, capacitors, and transistors, a printed circuit board with specific functions can be formed to meet the needs of corresponding electronic devices.

[0003] Capacitors are commonly used electronic components for functions such as DC blocking, coupling, filtering, and energy conversion. In related technologies, capacitors used in printed circuit boards (PCBs) are typically discrete components in cylindrical or cuboid form, mounted on a carrier board via soldering or insertion. This not only occupies surface area of ​​the PCB but also increases its overall thickness, limiting circuit integration. Conversely, using smaller capacitors would increase the cost of the PCB. Summary of the Invention

[0004] Some embodiments of this application provide a capacitor and a circuit board with the capacitor, which can reduce the cost and size of the circuit board.

[0005] In a first aspect, some embodiments of this application provide a circuit board, including:

[0006] A first printed circuit board; the first printed circuit board includes a first metal layer;

[0007] A preset functional module is disposed on the first surface of the first printed circuit board;

[0008] The preset functional module includes: a second printed circuit board; the second printed circuit board includes a second metal layer;

[0009] And, preset capacitor;

[0010] The first electrode of the preset capacitor is disposed on the first metal layer;

[0011] The second electrode of the preset capacitor is disposed on the second metal layer;

[0012] A preset insulating layer is provided between the first metal layer and the second metal layer; the preset insulating layer corresponds to the area of ​​the first electrode plate and the second electrode plate, and serves as the dielectric layer of the preset capacitor;

[0013] The first and second plates of the preset capacitor are respectively connected to preset ports on the first or second printed circuit board.

[0014] Compared to discrete component capacitors commonly used in related technologies, such as MLCCs, the above embodiments utilize the structural characteristics of the multilayer printed circuit board itself, namely, having multiple metal layers and an insulating layer between adjacent metal layers. The upper and lower plates of the preset capacitor required by the circuit board are formed by the idle metal areas in the relevant metal layers, and the insulating layer between the relevant metal layers serves as the dielectric layer of the preset capacitor. No additional materials or discrete components are needed, and the thickness of the circuit board is not increased. This effectively controls the cost and size of the capacitor and the circuit board, which is beneficial to the miniaturization and high integration of the circuit board.

[0015] In addition, compared with the implementation method of completely embedding the preset capacitor in the first printed circuit board or the second printed circuit board, in the above embodiment, the two plates of the preset capacitor are respectively disposed in the metal layer of the two printed circuit boards. The material and thickness of the insulating layer between the two plates can be adaptively configured during the process of soldering or bonding the two printed circuit boards, so as to meet the different requirements of different application scenarios in terms of circuit board size, integration, etc., and the circuit board design layout also has greater flexibility.

[0016] In some embodiments, the preset capacitor is a power filter capacitor, the first plate is grounded, and the second plate is connected to the power port of the preset functional module to filter out high-frequency harmonics in the voltage signal provided by the power port.

[0017] In the above embodiments, for application scenarios that require power filtering, it is only necessary to ground one plate of the preset capacitor and connect the other plate to the port corresponding to the power signal to be filtered; while for scenarios that require other functions to be achieved through the preset capacitor, it is only necessary to change the connection method of the first plate and the second plate accordingly and connect them to the relevant components or metal lines located in other metal layers, which is convenient and flexible.

[0018] In some embodiments, the second printed circuit board further includes a third metal layer; the power port is disposed on the third metal layer;

[0019] The third metal layer is also provided with a power lead; one end of the power lead is connected to the power port, and the other end of the power lead is connected to the second electrode plate through a via.

[0020] In the above embodiments, the power port and the electrode plate of the preset capacitor are not on the same metal layer. The connection between the second electrode plate of the preset capacitor and the power port can be achieved through vias, power leads, etc., to meet the functional requirements of the preset capacitor. Moreover, the related process is also a common technology and will not increase the circuit board manufacturing cost.

[0021] In some embodiments, the first metal layer is a ground layer in the first printed circuit board.

[0022] In the above embodiments, the first metal layer is a ground layer, and the first electrode plate disposed in the first metal layer is also directly grounded. This not only eliminates the need for a grounding lead, but also reduces the return path of current from the power source to the ground, avoids the generation of return inductance, and ensures the performance of the preset capacitor.

[0023] In some embodiments, the preset insulating layer is a solder resist layer covering the first surface of the first printed circuit board;

[0024] The first metal layer is the metal layer in the first printed circuit board that is close to the first surface;

[0025] The second metal layer is the metal layer in the second printed circuit board that is close to the first printed circuit board.

[0026] Since the second printed circuit board is located on the first surface of the first printed circuit board, the metal layer in the first printed circuit board that is close to its first surface and the metal layer in the second printed circuit board that is close to the first printed circuit board are adjacent metal layers. There are no other metal layers between them, only a solder resist layer. Therefore, the above two metal layers are respectively used as the first metal layer and the second metal layer. That is, the first electrode plate and the second electrode plate are respectively set in the above two metal layers, and the solder resist layer is directly used as the dielectric layer to form the preset capacitor. The related preparation process is simple and easy to implement.

[0027] In addition, using the solder mask as the dielectric layer can ensure that the dielectric layer has a smaller thickness. When the required capacitance value is fixed, the area of ​​the two plates facing each other is also relatively small, thereby reducing the circuit board area occupied by the preset capacitor and further improving the integration of the circuit board.

[0028] In some embodiments, at least one spacer metal layer is provided between the first metal layer and the second metal layer;

[0029] The region in the spacer metal layer corresponding to the second electrode is etched and filled with the same insulating material as the dielectric layer.

[0030] In the above embodiments, the two metal layers that form the first electrode plate and the second electrode plate may not be adjacent metal layers. There may be other metal layers between them to meet the design requirements of the dielectric layer thickness, electrode plate area, etc. of the preset capacitor under different application scenarios.

[0031] In some embodiments, the facing area S between the first electrode and the second electrode and the dielectric constant ε of the dielectric layer are positively correlated with the capacitance value C of the preset capacitor; the thickness d of the dielectric layer is negatively correlated with the capacitance value C of the preset capacitor.

[0032] Based on the circuit board with capacitor provided in the above embodiments, all parameters related to the capacitance value of the capacitor can be adjusted as needed during the manufacturing process, thereby obtaining a circuit board that meets different application requirements. This not only effectively controls the cost and size of the circuit board, but also makes the design and manufacturing of the circuit board more flexible.

[0033] In some embodiments, the area of ​​the first electrode plate is not less than the area of ​​the second electrode plate, such that the area S between the first electrode plate and the second electrode plate is equal to the area of ​​the second electrode plate.

[0034] In the above embodiments, the area of ​​the first electrode plate is greater than or equal to the area of ​​the second electrode plate, which can reduce the alignment accuracy between the first electrode plate and the second electrode plate, avoid alignment error causing the area S error of the two electrodes plate to be opposite each other, and thus ensure the accuracy of the capacitance value of the formed preset capacitor.

[0035] In some embodiments, the preset functional module includes an Internet of Things patch module.

[0036] In the above embodiments, the IoT patch module, as a preset functional module, is set on the first printed circuit board to form a circuit board. This not only allows the preset capacitors required for the IoT patch module to be formed based on the inherent metal layer of the circuit board, effectively controlling the overall size and cost of the circuit board, but also allows other components to be set on the first printed circuit board according to application requirements to connect with the IoT patch module to form a more complete product, which helps to miniaturize related products.

[0037] Secondly, some embodiments of this application provide a capacitor applied to a circuit board;

[0038] The circuit board includes: a first printed circuit board, and a preset functional module disposed on a first surface of the first printed circuit board;

[0039] The first printed circuit board includes a first metal layer;

[0040] The preset functional module includes: a second printed circuit board; the second printed circuit board includes a second metal layer;

[0041] The capacitor includes:

[0042] The first electrode plate is disposed on the first metal layer;

[0043] The second electrode plate is disposed on the second metal layer;

[0044] And, a dielectric layer is disposed on a preset insulating layer, wherein the preset insulating layer is located between the first metal layer and the second metal layer;

[0045] The first electrode plate and the second electrode plate are respectively connected to a preset port on the first printed circuit board or the second printed circuit board.

[0046] The capacitors provided in the above embodiments are formed based on the metal layer of the circuit board on which they are located. No additional materials are needed, and the thickness of the circuit board is not increased. Compared with commonly used ceramic capacitors, this not only reduces costs but also reduces the space occupied by the capacitors in the circuit board, thereby improving the integration of the circuit board. Attached Figure Description

[0047] To more clearly illustrate the implementation methods in some embodiments or related technologies of this application, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings.

[0048] Figure 1 The following are schematic diagrams of the circuit board structure in some embodiments of this application;

[0049] Figure 2 A three-dimensional structural schematic diagram of a circuit board with capacitors provided in some embodiments of this application is shown;

[0050] Figure 3 A cross-sectional structural schematic diagram of a circuit board with capacitors provided in some embodiments of this application is shown;

[0051] Figure 4 The equivalent circuit related to the power supply filter capacitor in some embodiments of this application is shown, along with a comparison diagram of the signal before and after filtering.

[0052] Figure 5 A schematic diagram of another capacitor-equipped circuit board provided in some embodiments of this application is shown;

[0053] Figure 6 A schematic diagram of the structure of another circuit board with capacitors according to some embodiments of this application is shown;

[0054] Figure 7 The diagram shows simulation results of the power supply filter capacitors in some embodiments of this application. Detailed Implementation

[0055] To make the objectives and implementation methods of this application clearer, the exemplary implementation methods of this application will be clearly and completely described below with reference to the accompanying drawings of the exemplary embodiments of this application. Obviously, the exemplary embodiments described are only some embodiments of this application, and not all embodiments.

[0056] It should be noted that the brief descriptions of terms in this application are only for the convenience of understanding the embodiments described below, and are not intended to limit the embodiments of this application. Unless otherwise stated, these terms should be understood in their ordinary and common meaning.

[0057] The terms "first," "second," "third," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar or related objects or entities, and do not necessarily imply a specific order or sequence, unless otherwise specified. It should be understood that such terms are interchangeable where appropriate.

[0058] The terms “comprising” and “having”, and any variations thereof, are intended to cover but not exclude inclusion, for example, a product or device that includes a range of components is not necessarily limited to all of the components that are clearly listed, but may include other components that are not clearly listed or that are inherent to such product or device.

[0059] In circuit board design, capacitors are typically used to perform functions such as DC blocking, coupling, bypassing, filtering, tuning circuits, energy conversion, and control circuits. Capacitors used on circuit boards are usually packaged as discrete components with fixed capacitance values. They can be fixed to the appropriate location on the circuit board through soldering, plug-in connections, or other methods, and are electrically connected to related components on the circuit board.

[0060] like Figure 1 The schematic diagram of a circuit board 100 shown has a patterned metal layer 111 on the surface of its carrier board 110 formed by processes such as printing and etching. It also has integrated chips 120 (such as processors, controllers, etc.), capacitors 131 and 132, and components such as resistors and inductors not shown in the figure. These components are connected to metal lines, pads or contacts in the metal layer 111, so that the circuit board 100 as a whole has the corresponding circuit functions.

[0061] Commonly used capacitors in circuit boards include different types such as electrolytic capacitors and multilayer ceramic capacitors (MLCCs). Figure 1 The capacitors 131 and 132 shown are typically cylindrical or cuboid in shape. Figure 1 It can be seen that compared to electronic components such as chip 120, capacitors have a greater height. After being fixed on the circuit board, they not only occupy the surface area of ​​the circuit board carrier, but also greatly increase the overall thickness of the circuit board, which is not conducive to the miniaturization and high integration of the circuit board. On the other hand, if small-sized capacitors with high capacitance density are used, the cost of the circuit board will increase.

[0062] In view of the above, some embodiments of this application provide a circuit board with capacitors, which will be described in detail below with reference to the accompanying drawings.

[0063] Figure 2 and Figure 3 These are, respectively, a three-dimensional structural schematic diagram and a cross-sectional structural schematic diagram of a circuit board with a capacitor provided in some embodiments of this application.

[0064] Reference Figure 2 and Figure 3 The circuit board 200 includes a first printed circuit board 210 and a preset functional module 220. The first printed circuit board 210 serves as a carrier board, and the preset functional module 220 is disposed on the first surface 210a of the first printed circuit board 210.

[0065] In some embodiments, such as Figure 3 As shown, the first printed circuit board 210 can be a multilayer printed circuit board with two metal layers, that is, the first printed circuit board 210 includes an insulating layer 211-1 as a core board, a metal layer 212-1 located on the upper surface of the insulating layer 211-1, and a metal layer 212-2 located on the lower surface of the insulating layer 211-1.

[0066] For example, the metal layers 212-1 and 212-2 in the first printed circuit board 210 can be patterned metal layers formed on the upper and lower surfaces of the insulating layer 211-1 based on processes such as printing or etching, and their specific circuit patterns are determined according to the relevant circuit structure and component layout.

[0067] For example, 211-1, which serves as the core board, can be made of FR-4 grade glass fiber cloth substrate.

[0068] In some embodiments, the preset function module 220 includes a second printed circuit board (PCB) and may also include relevant electronic components disposed on the second PCB to realize the preset function corresponding to the preset function module 220. The second PCB has at least one metal layer; the connecting wires, pads, contacts, etc. required by the relevant electronic components may be disposed in the metal layer of the second PCB.

[0069] In some embodiments, such as Figure 3 As shown, the second printed circuit board in the preset functional module 220 can be a multilayer printed circuit board with four metal layers; that is, the second printed circuit board can include four metal layers 222-1, 222-2, 222-3 and 222-4, and insulating layers 221-1, 221-2 and 221-3 between two adjacent metal layers.

[0070] For example, the second printed circuit board with four metal layers can be formed by bonding two laminated printed circuit boards with two metal layers (hereinafter referred to as laminated printed circuit boards A and B, respectively) together with an adhesive material such as a prepreg.

[0071] Reference Figure 3The two stacked printed circuit boards A and B that make up the second printed circuit board can use insulating layers 221-1 and 221-3 as core boards, respectively; metal layers 222-1 and 222-2 are the two metal layers corresponding to the stacked printed circuit board A, respectively disposed on the lower and upper surfaces of the insulating layer 221-1; metal layers 222-3 and 222-4 are the two metal layers corresponding to the stacked printed circuit board B, respectively disposed on the lower and upper surfaces of the insulating layer 221-3; the insulating layer 221-2 is a prepreg for bonding the two stacked printed circuit boards A and B.

[0072] It is understood that in other embodiments, depending on the circuit complexity of the preset functional module, the total number of metal layers contained in the second printed circuit board may also be two layers, eight layers, etc.; the total number of metal layers contained in the first printed circuit board as the carrier board may also be four layers, eight layers, etc. That is, the first printed circuit board and the second printed circuit board in the relevant embodiments of this specification can both be multilayer printed circuit boards, but the number of metal layers contained therein can be adaptively configured according to the actual circuit wiring complexity, the number of required components, etc., and this specification does not limit this.

[0073] In some embodiments, such as Figure 3 As shown, the first surface 210a and the second surface 210b of the first printed circuit board 210 are respectively provided with solder resist layers 213-1 and 213-2 to protect the metal layers 212-1 and 212-2 of the two surfaces, so as to prevent solder from flowing into the area that does not need to be soldered during the process of soldering the preset functional module 220 or other components on the first printed circuit board 210, and also to prevent the metal lines in the metal layers from oxidizing and corroding.

[0074] For example, the materials used in the above-mentioned solder resist layers 213-1 and 213-2 can be polymer compound coatings whose main component is epoxy resin, which are formed on the surface of the first printed circuit board through processes such as coating; because its color is usually green, it can also be called green oil insulation layer.

[0075] In some embodiments, a portion of the metal layer 222-1 and a portion of the metal layer 212-1 can be used as soldering points on the second printed circuit board and the first printed circuit board 210, respectively, and soldered with solder 240 to solder the preset functional module 220 to the first surface 210a of the first printed circuit board 210.

[0076] The aforementioned circuit board 200 also includes a preset capacitor; depending on the connection method, the preset capacitor can perform different functions such as DC blocking and filtering. The preset capacitor can be a parallel plate capacitor, such as a metal-insulator-metal (MIM) structure capacitor; wherein, the metal plates of the preset capacitor can be formed based on the metal layer in the first or second printed circuit board of the circuit board 200.

[0077] In some embodiments, the aforementioned preset capacitor can be embedded in the first printed circuit board 120, that is, the two plates of the aforementioned preset capacitor can be formed based on two metal layers in the first printed circuit board 120, such as metal layers 212-1 and 212-2; correspondingly, the insulating layer between the two metal layers where the two plates are located, such as insulating layer 211-1, can serve as the dielectric layer of the aforementioned preset capacitor.

[0078] In some embodiments, the aforementioned preset capacitor can also be embedded in the second printed circuit board. That is, the two plates of the preset capacitor can be formed based on any two metal layers in the second printed circuit board, such as metal layers 222-1 and 222-2, metal layers 222-2 and 222-3, etc. The insulating layer between the two metal layers where the two plates are located, such as insulating layer 221-1 (the two plates are located in metal layers 222-1 and 222-2 respectively), can serve as the dielectric layer of the preset capacitor.

[0079] In the above embodiments, the preset capacitor is embedded in the first printed circuit board or the second printed circuit board. The thickness of its dielectric layer and the dielectric constant are limited by the thickness of the insulating layer such as the core board or prepreg in the multilayer printed circuit board and the materials used. Therefore, to prepare preset capacitors with different capacitance values, only the area of ​​the metal region corresponding to the first electrode plate or the second electrode plate can be adjusted.

[0080] In some embodiments, the first electrode of the preset capacitor may be disposed on the first metal layer of the first printed circuit board 210, and the second electrode of the preset capacitor may be disposed on the second metal layer of the second printed circuit board; a preset insulating layer is provided between the first metal layer and the second metal layer, and the preset insulating layer corresponding to the area of ​​the first electrode and the second electrode can be used as the dielectric layer of the preset capacitor.

[0081] For example, such as Figure 2 and Figure 3 As shown, the bottom metal layer of the second printed circuit board (i.e., the metal layer closest to the first printed circuit board 210 among the multiple metal layers of the second printed circuit board), namely metal layer 222-1, can serve as the aforementioned second metal layer; in metal layer 222-1 (i.e., the second metal layer), an independent metal region 222-1c can be formed by etching or other processes. This metal region 222-1c is not connected to other metal lines or metal regions in the same layer and can serve as the second electrode of the preset capacitor 230.

[0082] Correspondingly, such as Figure 2 and Figure 3As shown, the top metal layer of the first printed circuit board 210 (i.e., the metal layer closest to the first surface 210a among the multiple metal layers of the first printed circuit board 210), namely metal layer 212-1, can serve as the aforementioned first metal layer; in metal layer 212-1 (i.e. the first metal layer), the metal region 212-1c that is directly opposite to the metal region 222-1c can serve as the first electrode of the preset capacitor 230.

[0083] The insulating layer 213-1 located between the two metal regions 222-1c and 212-1c can serve as the dielectric layer of the preset capacitor 230.

[0084] Compared to discrete component capacitors commonly used in related technologies, such as MLCCs, the above embodiments utilize the structural characteristics of the multilayer printed circuit board itself, namely, having multiple metal layers and an insulating layer between adjacent metal layers. The upper and lower plates of the preset capacitor required by the circuit board 200 are formed by the idle metal areas in the relevant metal layers, and the insulating layer between the relevant metal layers serves as the dielectric layer of the preset capacitor. No additional materials or discrete components are needed, and the thickness of the circuit board 200 is not increased. This effectively controls the cost and size of the capacitor and the circuit board, which is beneficial to the miniaturization and high integration of the circuit board.

[0085] According to the formula for determining capacitance, C = ε*S / d, the capacitance value C of the preset capacitor 230 is positively correlated with the area S between its two plates and the dielectric constant ε of the dielectric layer, and negatively correlated with the thickness d of the dielectric layer.

[0086] Therefore, compared to the implementation where two plates are placed in other metal layers that are far apart, in the above embodiment, adjacent metal layers 212-1 and 222-1 are used as the first metal layer and the second metal layer, respectively, and the first plate and the second plate of the preset capacitor 230 are respectively placed on them. Thus, the single insulating layer 213-1 located between them can serve as the dielectric layer of the preset capacitor 230, so that the dielectric layer of the formed preset capacitor has a smaller thickness.

[0087] Given a fixed capacitance value, the smaller the dielectric layer thickness d, the smaller the corresponding facing area S, which means the smaller the circuit board area occupied by the first or second electrode plate. Therefore, the above embodiments can further improve the integration of the circuit board.

[0088] Reference Figure 2 and Figure 3 The pre-defined area S between the two plates of the capacitor 230 is the overlapping area between the metal regions 222-1c and 212-1c; the dielectric constant ε of the dielectric layer is the dielectric constant of the insulating layer 213-1; and the thickness d of the dielectric layer is the thickness of the insulating layer 213-1 located between the two metal regions 222-1c and 212-1c.

[0089] In some embodiments, the areas of the first plate and the second plate of the preset capacitor 230 may be the same or different. If the areas of the two plates of the preset capacitor 230 are the same and they completely overlap, then the area S directly opposite is the area of ​​either plate; if the areas of the two plates of the preset capacitor 230 are different, and the projection of the smaller plate falls completely within the larger plate, then the area S directly opposite is the area of ​​the smaller plate.

[0090] In some embodiments, the preset capacitor 230 can be fabricated such that the area of ​​the first electrode is not less than the area of ​​the second electrode. For Figure 2 and Figure 3 The structure shown means that the area of ​​the metal region 222-1c, which serves as the first electrode plate, is not less than the area of ​​the metal region 222-1c, which serves as the second electrode plate.

[0091] In this way, the alignment accuracy of the first and second plates can be reduced, avoiding the error in the area S of the two plates due to alignment error, which also avoids the error in the capacitance value of the preset capacitor 230.

[0092] For example, refer to Figure 2 and Figure 3 Assuming the length of the metal region 222-1c is denoted as L1 and the width as W1; under the premise that the projection of the metal region 222-1c on the first metal layer falls completely within the metal region 222-1c, the area S between the two plates of the preset capacitor 230 is the area of ​​the metal region 222-1c, which is L1*W1.

[0093] Correspondingly, the capacitance determination formula for the preset capacitor 230 can be transformed into: Where, ε r The dielectric layer of the preset capacitor 230, i.e., the insulating layer 213-1, has the dielectric constant relative to vacuum; ε0 is the dielectric constant of vacuum, approximately 8.85 × 10⁻⁶. -12 F / m.

[0094] In some embodiments, when the material used for the insulating layer 213-1, which serves as the dielectric layer, is determined, its dielectric constant ε and relative dielectric constant ε r Therefore, it is determined that during the circuit board manufacturing process, the preset capacitance 230 with different capacitance values ​​can be achieved by adjusting the thickness d of the insulating layer 213-1 as the dielectric layer and the size of the metal region 222-1c as the second electrode plate (including adjusting its length L1 or width W1).

[0095] For example, assuming the capacitance value C of the preset capacitor 230 required for the circuit board 200 is 100pF, when manufacturing the circuit board 200, the relative permittivity ε of the material used as the insulating layer 213-1, which serves as the dielectric layer, is... rGiven a capacitance of 3.5 and a thickness d of 0.02 mm, the area S of the metal region 222-1c serving as the second electrode can be calculated using the capacitance formula:

[0096]

[0097] Given a fixed area S in the metal region 222-1c, the product of L1 and W1 is determined. The values ​​of L1 and W1 can be combined in various ways, such as L1 = 0.8 mm, W1 = 0.8 mm, or L1 = 1 mm, W1 = 0.64 mm, etc. The specific value can be determined according to actual needs.

[0098] In some embodiments, in different application scenarios, insulating materials with different dielectric constants can be selected to form insulating layer 213-1 according to actual needs, so that the electrode size (such as L1 and W1) and dielectric layer thickness d of the preset capacitor 230 have a wider range of options, which is beneficial to control the space occupied by the preset capacitor 230 in the circuit board 200.

[0099] Unlike the implementation where the preset capacitor is completely embedded in the first or second printed circuit board, in the above embodiment, the two plates of the preset capacitor are respectively disposed in the metal layers of the two printed circuit boards. The material and thickness of the insulating layer between the two plates can be adaptively configured during the process of soldering or bonding the two printed circuit boards.

[0100] In this way, all parameters that determine the capacitance value of the preset capacitor, including the facing area of ​​the two plates, the dielectric constant of the dielectric layer, and the thickness of the dielectric layer, can be controlled and adjusted during the circuit board design and manufacturing process. This can meet the different requirements of different application scenarios in terms of circuit board size and integration, and the circuit board design layout also has greater flexibility.

[0101] Furthermore, based on the above embodiments, a preset capacitor 230 with arbitrary capacitance value can be fabricated on the circuit board, eliminating the need for series and parallel connection of multiple discrete capacitor elements with fixed capacitance values ​​as in related technologies. From this perspective, the above embodiments can also reduce circuit board costs, decrease circuit board size, and improve integration.

[0102] Depending on the different functions that the preset capacitor 230 is to perform in the circuit board 200, its first plate and second plate can have different connection methods and be connected to different components or metal lines located in other different metal layers.

[0103] In some embodiments, the preset capacitor 230 can be a power supply filter capacitor, that is, the preset capacitor 230 is used to filter the relevant power supply in the circuit board 200 to ensure the stability of the power supply signal.

[0104] The second printed circuit board of the preset function module 220 also includes a third metal layer; the power port in the circuit board 200 is located in the third metal layer.

[0105] In this case, to achieve the power filtering function, the connection method of the two plates of the preset capacitor 230 can be as follows: the second plate, which is set in the second metal layer of the second printed circuit board, can be connected to the power port located in the third metal layer through a via; the first plate, which is set in the first metal layer of the first printed circuit board, can be grounded.

[0106] In some embodiments, such as Figure 2 and Figure 3 As shown, the metal layer 222-4 of the second printed circuit board serves as the aforementioned third metal layer, and is provided with a power port 222-4P and a power lead 222-4L. One end of the power lead 222-4L is connected to the power port 222-4P, and the other end is connected to the metal region 222-1c (i.e., the second electrode plate located in the second metal layer) through a via 224. Based on this, grounding the metal region 212-1c (i.e., the first electrode plate located in the first metal layer) forms a preset capacitor 230 with power filtering function.

[0107] In some embodiments, the metal region 212-1c can be connected to the ground layer or grounding point of the first printed circuit board by means of leads or vias, thereby grounding the metal region 212-1c (i.e., the first plate of the preset capacitor 230).

[0108] In other embodiments, the metal layer 212-1 where the metal region 212-1c is located can be configured as the ground plane of the first printed circuit board to ground the metal region 212-1c (i.e., the first plate of the preset capacitor 230).

[0109] When the metal layer 212-1 is a ground layer, any point or area in the metal layer 212-1 is grounded, thus the metal area 212-1c, which serves as the first electrode plate, is grounded. There is no need to set a grounding lead for the first electrode plate, which simplifies the internal structure of the circuit board and the circuit board manufacturing process.

[0110] In addition, configuring the metal layer 212-1 as a grounding layer not only eliminates the need for the grounding lead corresponding to the first plate, but also reduces the return path of current from the power supply to the ground, avoids the generation of return inductance, and ensures the performance of the preset capacitor 230.

[0111] Figure 4 The equivalent circuit diagram of the preset capacitor 230 as a power filter to filter the operating voltage VCC of the preset functional module 220 is shown, along with a comparison diagram of the voltage signals before and after filtering.

[0112] Reference Figure 4 The equivalent circuit shown has one end of capacitor 230 connected to the operating voltage and the other end grounded, corresponding to... Figure 2 One plate of the preset capacitor 230 is connected to the aforementioned power port 222-4P, and the other plate is grounded; the two voltage signal sampling points M and N in the equivalent circuit correspond to respectively Figure 2 Points M' and N' in the power lead 222-4L shown; the sampling signal corresponding to point M is the voltage signal obtained by sampling at point M', which is the voltage signal before filtering; the sampling signal corresponding to point N is the voltage signal obtained by sampling at point N', which is the voltage signal after filtering.

[0113] contrast Figure 4 As shown in the voltage signals before and after filtering, it can be seen that the preset capacitor 230 can effectively filter out high-frequency harmonics in the working voltage VCC, making the working voltage VCC in the input preset function module 220 more stable.

[0114] Figure 2 and Figure 3 In the embodiment shown, the two metal layers 212-1 and 222-1 where the first and second plates of the preset capacitor 230 are located are adjacent. One is the top metal layer of the first printed circuit board, and the other is the bottom metal layer of the second printed circuit board. There is only an insulating layer between them, and no other metal layers.

[0115] In some embodiments, at least one spacer metal layer may also be present between the two metal layers containing the first and second plates of the preset capacitor 230. For example... Figure 5 As shown, the first printed circuit board 210 can also be a multilayer printed circuit board with four metal layers; these four metal layers are metal layers 212-1, 212-2, 212-3 and 212-4 respectively; insulating layers 211-1, 211-2 and 211-3 are respectively provided between two adjacent metal layers.

[0116] Among them, the metal layer 212-2 in the first printed circuit board 210 is a first metal layer with a first electrode plate, that is, the first electrode plate of the preset capacitor 230 is the metal region 212-2c in the metal layer 212-2.

[0117] The second plate of the preset capacitor 230 is still the metal area 222-1c in the second printed circuit board.

[0118] like Figure 5 As shown, between the first metal layer (i.e., metal layer 212-2) on which the first electrode plate is disposed and the second metal layer (i.e., metal layer 222-1) on which the second electrode plate is disposed, there is also a spacer metal layer, namely the metal layer 212-1 located on the top layer of the first printed circuit board.

[0119] In the case where there is at least one spacer metal layer between the first metal layer and the second metal layer, in order to form the preset capacitor 230, the areas of each spacer metal layer and the associated insulating layer corresponding to the first electrode or the second electrode can be completely etched away and filled with insulating material to form a dielectric layer.

[0120] like Figure 5 As shown, the area between the metal region 212-2c, which serves as the first electrode plate, and the metal region 222-1c, which serves as the second electrode plate, consists of an insulating layer 211-1, a metal layer 212-1, and a solder resist layer 213-1, which can be completely etched away and replaced with an insulating material with a dielectric constant of a set value to form a dielectric layer 211-c.

[0121] based on Figure 5 In practical applications, when selecting the insulating material used to form the dielectric layer, the dielectric constant setting value ε corresponding to the dielectric layer can be calculated and determined based on the capacitance value C of the preset capacitor 230, the distance between the first metal layer and the second metal layer (i.e., the thickness d of the dielectric layer), the area S = L1 × W1 of the second electrode plate, etc. Then, an insulating material that meets the dielectric constant setting value ε is selected and filled between the metal region 212-2c and the metal region 222-1c to form a dielectric layer that meets the design requirements of the preset capacitor 230.

[0122] In some embodiments, Figure 5 The structure shown can be applied to the case where the first printed circuit board 210 uses the middle metal layer as the ground layer. This ensures that the metal layer where the first electrode of the preset capacitor 230 is located is the ground layer, eliminating the need for grounding leads, reducing the return current path, and ensuring the performance of the preset capacitor 230.

[0123] Figure 5 In the structure shown, the first plate of the preset capacitor 230 is located in the middle metal layer of the first printed circuit board (i.e., the middle metal of the first printed circuit board is used as the first metal layer). In other embodiments, the second plate of the preset capacitor 230 can also be disposed in the middle metal layer of the second printed circuit board (i.e., the middle metal layer of the second printed circuit board is used as the second metal layer).

[0124] like Figure 6 As shown, the metal layer 222-2 of the second printed circuit board serves as the second metal layer, and the metal region 222-2c therein serves as the second electrode of the preset capacitor 230. Simultaneously, the area between metal region 222-2c and metal region 212-1c is entirely filled with an insulating material with a set dielectric constant, forming dielectric layer 211-c. The selection of the insulating material can be referred to the relevant embodiments described above, and will not be repeated here.

[0125] In some embodiments, the preset functional module 230 can be an IoT patch module, such as a WIFI module, Bluetooth module, Narrow Band Internet of Things (NB-IoT) module, etc., which can communicate with relevant host devices as an independent modular product.

[0126] The IoT patch module is placed on the first printed circuit board 210 to form a circuit board 200. This not only facilitates the formation of the preset capacitor 230 required for the IoT patch module, but also allows other components, such as sensors and controllers, to be placed on the first printed circuit board 210 according to application requirements, so as to connect with the IoT patch module to form a more complete product, such as various sensing devices and IoT smart devices.

[0127] based on Figure 2 and Figure 3 The structure shown, for the application scenario where the preset capacitor 230 is used as a power filter, allows W1, L1, and ε to be used. r The relevant data such as d are input into the electromagnetic simulation software to simulate the preset capacitor 230 in order to verify its filtering performance. Figure 7 The simulation results show the scattering parameters, i.e. the S-parameters, of the preset capacitor 230, including the input reflection coefficient S(1,1), the reverse transmission coefficient S(1,2), the forward transmission coefficient S(2,1), and the output reflection coefficient S(2,2).

[0128] Reference Figure 7 Based on the two key points m1 and m2 shown in the curve illustrating the variation of the reverse gain transmission coefficient S(1,2) with the input frequency freq, it can be seen that when the input frequency freq is approximately 2.4 GHz, the parameter S(1,2) is 13.360 dB (corresponding to point m1); and when the input frequency is approximately 5 GHz, the parameter S(1,2) is 15.904 dB (corresponding to point m2). In other words, in both the 2.4 GHz and 5 GHz frequency bands, the reverse gain transmission coefficient of the preset capacitor 230 is greater than 13 dB, indicating that the preset capacitor 230 has high isolation in both frequency bands, ensuring effective filtering of high-frequency harmonics.

[0129] In addition, some embodiments of this application also provide a small-sized, low-cost capacitor.

[0130] This capacitor is used in a circuit board. The circuit board has a first printed circuit board and a preset functional module disposed on a first surface of the first printed circuit board; wherein, the first printed circuit board includes a first metal layer; the preset functional module includes: a second printed circuit board; the second printed circuit board includes a second metal layer;

[0131] Based on the circuit board described above, some embodiments of the capacitor may include: a first electrode plate disposed on the first metal layer, a second electrode plate disposed on the second metal layer, and a dielectric layer disposed on a preset insulating layer.

[0132] The aforementioned preset insulating layer is located between the first metal layer and the second metal layer, and thus the region in the preset insulating layer located between the first electrode plate and the second electrode plate can serve as a dielectric layer.

[0133] In different embodiments, the first electrode and the second electrode can be connected to different preset ports on the first printed circuit board or the second printed circuit board, so that the capacitor can perform different functions. The specific structure of the capacitor in the circuit board can be referred to the relevant embodiments above, and will not be repeated here.

[0134] The capacitors provided in the above embodiments are formed based on the metal layer of the circuit board on which they are located. No additional materials are needed, and the thickness of the circuit board is not increased. Compared with commonly used ceramic capacitors, this not only reduces costs but also reduces the space occupied by the capacitors in the circuit board, thereby improving the integration of the circuit board.

[0135] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

[0136] For ease of explanation, the above description has been provided in conjunction with specific embodiments. However, the above exemplary discussion is not intended to be exhaustive or to limit the embodiments to the specific forms disclosed above. Various modifications and variations can be obtained based on the above teachings. The selection and description of the above embodiments are for the purpose of better explaining the principles and practical applications, thereby enabling those skilled in the art to better utilize the described embodiments and various different variations of embodiments suitable for specific use considerations.

Claims

1. A circuit board, characterized by, The application relates to a circuit board. The first printed board comprises a first metal layer. The preset function module is arranged on the first surface of the first printed board. The preset function module comprises a second printed board, and the second printed board comprises a second metal layer. The preset capacitor comprises a first electrode plate arranged on the first metal layer, a second electrode plate arranged on the second metal layer, and a dielectric layer arranged on a preset insulating layer between the first metal layer and the second metal layer. The preset capacitor is a power filter capacitor, the first electrode plate is grounded, and the second electrode plate is connected with a power port of the preset function module to filter high-frequency harmonics in a voltage signal provided by the power port. The second printed board further comprises a third metal layer, and the power port is arranged on the third metal layer. The third metal layer is further provided with a power lead, one end of the power lead is connected with the power port, and the other end of the power lead is connected with the second electrode plate through a via hole. The first metal layer is a grounding layer in the first printed board.

2. The circuit board of claim 1, wherein The preset insulating layer is a solder mask layer on the first surface of the first printed board.

3. The circuit board of claim 2, wherein The first metal layer is a metal layer close to the first surface in the first printed board. The second metal layer is a metal layer close to the first printed board in the second printed board.

4. The circuit board of claim 2, wherein The first metal layer and the second metal layer have at least one interval metal layer.

5. The circuit board of claim 1, wherein The interval metal layer is etched and filled with the same insulating material as the dielectric layer in a region corresponding to the second electrode plate. The facing area S between the first electrode plate and the second electrode plate, the dielectric constant epsilon of the dielectric layer and the capacitance value C of the preset capacitor are positively correlated. The area of the first electrode plate is not less than the area of the second electrode plate, so that the facing area S between the first electrode plate and the second electrode plate is equal to the area of the second electrode plate.

6. The circuit board of claim 1, wherein The preset function module comprises an Internet of Things patch module. The application is applied to a circuit board.

7. The circuit board of claim 1, wherein The circuit board comprises a first printed board and a preset function module arranged on the first surface of the first printed board.

8. The circuit board of claim 1, wherein, The first printed board comprises a first metal layer.

9. The circuit board of claim 1, wherein, The preset function module comprises a second printed board, and the second printed board comprises a second metal layer.

10. A capacitor, characterized by The capacitor comprises a first electrode plate arranged on the first metal layer, a second electrode plate arranged on the second metal layer, and a dielectric layer arranged on a preset insulating layer between the first metal layer and the second metal layer. ​ ​ ​ ​ ​ ​ ​

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