Printed circuit board and design method for resistance balance between PAD electroplated on printed circuit board

Abstract

The invention provides a printed circuit board and a design method for resistance balance between electroplated PADs on the printed circuit board, and particularly, all the electroplated PADs on the board surface of the printed circuit board are grouped according to the areas of the electroplated PADs on the board surface, in any electroplating PAD group, the electroplating PAD group is connected to a first guide wire adjacent to the electroplating PAD group through a second guide wire, and the electroplating PAD group is connected to a second guide wire through a third guide wire. And each electroplating PAD in the group is connected to one end of the second guide wire through the corresponding branch lead, so that the resistance of all the electroplating PAD on the printed circuit board is the same as the resistance of the conducting metal frame. According to the invention, the inter-group design and the intra-group design are carried out on the leads of the electroplated metal PAD, so that the arrangement mode and size of the leads are simplified while the resistance balance among all the electroplated PAD on the printed circuit board is effectively realized; the electroplating uniformity of all electroplated PADs on the surface of the printed circuit board is improved, meanwhile, the metal layer design of the board surface of the printed circuit board is simplified, the utilization rate of the board surface is improved, and the production cost is saved.

Description

Technical Field

[0001] The present invention relates to the field of printed circuit board manufacturing, and more particularly to a design method for resistance balance between a printed circuit board and an electroplated PAD thereon. Background Art

[0002] With the rapid development and widespread use of integrated circuits, the types and applications of electronic devices have rapidly expanded, and electronic products have become more intelligent and miniaturized. Consequently, the variety of printed circuit boards (PCBs) has continued to evolve, and the process requirements for PCBs have become increasingly complex. In today's PCB manufacturing, many are designed with electroplating to improve corrosion resistance, solderability, and conductivity. Electroplating, also known as gold plating, is a surface treatment technique that coats the PCB surface with a layer of metallic gold, typically gold, nickel-gold alloy, or gold-nickel. The goal is to evenly apply the gold to the PCB pads (PADs) through an electrochemical process. However, the most prominent problem with the current manufacturing process is the lack of uniformity in the electroplated gold coating. The thickness of the resulting gold coating varies significantly, typically by 50% to 100%. This increases the amount of gold used and significantly increases the cost of PCB production.

[0003] Gold pads (pads) on PCBs are crucial areas for achieving electrical interconnects, and the uniformity of the gold coating is crucial to their performance. To improve the uniformity of gold pads on PCBs, the following measures are commonly employed in production: 1. Controlling current density. During the electroplating process, current density significantly impacts plating uniformity. Adjusting the current density appropriately can ensure uniform plating across the gold pads on the PCB. 2. Optimizing the plating solution composition: Maintaining the chemical composition of the plating solution, such as gold salts, cyanide, and pH, within appropriate ranges helps ensure uniformity of the plated layer. 3. Adjusting process conditions: During the electroplating process, process conditions such as temperature, bath flow rate, and time also affect the uniformity of the plated layer. 4. Using specialized molds and plating fixtures allows for precise control of the plating process across the gold pads on the PCB. However, these measures are essentially improvements to the manufacturing process and do not fundamentally address the issue of gold pad uniformity. A method is needed that can be developed from within the printed circuit board design itself to fundamentally improve the uniformity of the plating across the gold pads.

[0004] Electroplated gold pads (PADs) on PCBs, such as gold fingers, serve as key areas for connecting to external interfaces on PCBs. They often require frequent plugging and unplugging, making them susceptible to poor contact or damage due to wear. To improve the durability and electrical performance of gold fingers, wires are typically placed around them to connect to the metal frame or other metal areas on the PCB. This enhances the gold fingers' structural strength and reduces the effects of mechanical wear. Furthermore, placing wires around the gold fingers to connect to the metal frame helps disperse the current load, lowering current density and minimizing losses within the gold fingers, thereby improving their long-term stability and reliability. Furthermore, the metal frame surrounding the gold fingers helps shield electromagnetic interference (EMI), particularly in PCB designs involving high-frequency signal transmission, by reducing signal loss and interference. When setting leads around the gold fingers to connect to the metal frame, the leads are also required to have sufficient conductivity and mechanical strength so that the leads can carry the current load of the area around the gold fingers, avoid overheating or damage caused by excessive current, and prevent breakage due to frequent plugging and unplugging or external force; at the same time, in the actual production process, it is recommended to use wider leads to avoid excessive impedance. The size and layout of the leads must ensure that they do not interfere with other functions in the gold finger area, while ensuring good electrical connection. Therefore, the layout of the leads should avoid excessive complexity to ensure that they do not affect the signal transmission layout of the PCB. Therefore, traditional electric gold leads often connect all gold fingers on the PCB directly to the main leads through parallel auxiliary leads and then further connect to the metal frame. The length of the auxiliary leads connected to all gold fingers is consistent, but the problem caused by this is that the total resistance of the gold fingers when connected to the main leads is different. A new lead design method needs to be developed so that the resistance values ​​of all gold-plated PADs set on the PCB can be consistent with the resistance value of the metal frame through their corresponding leads, thereby making the resistance values ​​of the gold-plated PADs to be plated on the entire board balanced, making the current more evenly distributed on the entire surface of the PCB, so that the metal ions in the plating solution can be evenly deposited during the electroplating process, thereby improving the uniformity of the plating layer; furthermore, the consistent resistance value of the gold-plated PADs on the PCB board surface helps to maintain current stability during the electroplating process, improve electroplating efficiency, and at the same time avoid local overheating, reducing thermal damage to the PCB surface.

[0005] Furthermore, the resistance balancing method through lead design can be used to ensure that the resistance of each electroplated PAD on the printed circuit board is consistent with the metal frame of the board edge. Therefore, it is extended to all metal electroplating processes on the PCB surface, such as nickel, gold, tin, and silver, so that all electroplated PADs can obtain the required plating layer of the same thickness, thereby improving the plating uniformity of the electroplated PAD on the printed circuit board, thereby improving the quality of the printed circuit board. At the same time, due to the uniform plating on the electroplated PAD on the printed circuit board, the amount of electroplated metal used is reduced, saving the cost of electroplating gold, nickel, tin, silver and other metals. Summary of the Invention

[0006] The present invention aims to overcome at least one of the above-mentioned defects of the prior art and provides a design method for balancing the resistance between a printed circuit board and the electroplated PADs thereon. By balancing the leads connected to the electroplated PADs, it is ensured that the resistance of each electroplated PAD on the printed circuit board is consistent with the metal frame at the edge of the board, thereby improving the uniformity of electroplating on the entire printed circuit board.

[0007] The technical solution adopted by the present invention first provides a design method for resistance balance between electroplated PADs on a printed circuit board. The printed circuit board is provided with a conductive metal frame along the board edge, and a plurality of electroplated PADs are provided on the board surface of the printed circuit board. The electroplated PADs are connected to the conductive metal frame through corresponding leads. The design method is characterized in that the method includes the following steps: S1. The electroplating PAD is grouped according to the position of the electroplating PAD on the printed circuit board to form a plurality of electroplating PAD groups; the electroplating PAD group forms a rectangular area having a long side and a short side, and the direction of the electroplating PAD interval arrangement in the group is the direction of the long side; S2. Setting a plurality of first guide lines to separate all electroplated PAD groups provided on the board surface, wherein the first guide lines are provided on the board surface of the printed circuit board and connected to the conductive metal frame, so that all electroplated PAD groups are adjacent to at least one first guide line; S3. In any electroplating PAD group, the electroplating PAD group is connected to the first guide line adjacent to it through the second guide line, and each electroplating PAD in the group is connected to one end of the second guide line through its corresponding branch lead, so that the resistance of all electroplating PADs and their corresponding leads on the printed circuit board is the same as the resistance of the conductive metal frame.

[0008] In the present technical solution, all the electroplated PADs on the surface of the printed circuit board are grouped according to their areas on the board surface, and the electroplated PADs are grouped according to their positions on the printed circuit board to form several electroplated PAD groups, so as to facilitate planning the position of the first guide line set on the board surface of the printed circuit board and connected to the conductive metal frame, so that all electroplated PAD groups are adjacent to at least one first guide line, so that the leads connecting the electroplated PADs to the first guide lines can be designed more freely, which not only avoids mutual interference between the leads of adjacent electroplated PADs, but also reduces the laying area and setting distance of the leads, simplifies the layout and size of the leads, and ensures the tolerance and reliability of the signal transmission layout on the printed circuit board; at the same time, the conductive metal frame is separated from the adjacent electroplated PAD by the first guide line, which can greatly reduce the edge effect on the printed circuit board and improve the electrical precision and reliability of the printed circuit board. Furthermore, in any electroplating PAD group, the electroplating PAD group is connected to the first guide line adjacent to it through a second guide line, and each electroplating PAD in the group is connected to one end of the second guide line through its corresponding branch lead, so that the resistance of all electroplated PADs on the printed circuit board is the same as the resistance of the conductive metal frame, and the leads of the electroplated metal PAD are designed between groups and within groups. By setting a second guide line to connect the electroplating PAD group and the first guide line adjacent to it, and by connecting all the electroplated PADs in the group to the second guide line and then to the first guide line, the resistance value difference of several electroplated PADs included in the electroplating PAD group is compressed to the setting of the branch lead, thereby effectively achieving resistance balance between electroplating PADs while simplifying the lead setting method and size, thereby improving the electroplating uniformity of all electroplated PADs on the surface of the printed circuit board while also simplifying the metal layer design of the printed circuit board surface, thereby improving the board surface utilization rate and saving production costs.

[0009] Furthermore, in any electroplating PAD group, the length and width of the branch lead corresponding to the electroplating PAD are changed according to the position of the electroplating PAD between the groups, so that the resistance value from each electroplating PAD to the second guide line is equal, and by changing the set length and width of the second guide line, the resistance of all electroplating PADs in each electroplating PAD group and the conductive metal frame is the same. In the present technical solution, the electroplating PAD group is connected to the first guide line adjacent to it through the second guide line, and all the electroplating PADs in the group are connected to the first guide line with their corresponding branch leads. Since the resistance value differences of several electroplating PADs included in the electroplating PAD group are compressed to the setting of the branch leads corresponding to the electroplating PADs, the length and resistance value of the first guide line when located in different areas of the board surface are determined by design between different electroplating PAD groups, and the resistance value of each electroplating PAD in the group is also determined by design. In order to keep the resistance value of each electroplating PAD in different electroplating PAD groups consistent with the conductive metal frame, the difference between each electroplating PAD group due to the corresponding first guide line and the electroplating PAD group's own resistance and the conductive metal frame resistance is compensated by the second guide line. By changing the setting length and width of the second guide line, the second guide line can be conveniently adjusted to the required resistance value, thereby effectively achieving resistance balance between electroplating PADs and improving the electroplating uniformity of the electroplating PAD on the board surface, while further simplifying the lead setting method and size.

[0010] Furthermore, in any electroplating PAD group, the branch leads include a first branch lead perpendicular to the long side and correspondingly connected to one electroplating PAD, and a second branch lead connecting the first branch lead and the second guide line. In this technical solution, since the electroplating PAD group forms a rectangular area, in order to avoid mutual influence between adjacent electroplating PADs, the branch leads connecting each electroplating PAD in the group respectively include a first branch lead perpendicular to the long side and correspondingly connected to one electroplating PAD, and a second branch lead connecting the first branch lead and the second guide line. The first branch leads ensure mutual isolation and independence between the electroplating PADs, and the size and position of the second branch leads are set to achieve resistance balance design for the electroplating PADs in the group.

[0011] Preferably, in one embodiment of the present invention, in any one electroplating PAD group, the connection point between the second guide line and the second branch lead is set on the center line of the long side of the rectangular area, and an inclined second branch lead is provided on both sides of the second guide line. The first branch lead is correspondingly connected to a plating PAD and further connected to the second branch lead; the inclination angle and width of the second branch lead are determined by the resistance values ​​of the plating PAD located on the center line of the long side of the rectangular area and the two electroplating PADs at both ends. In this technical solution, by setting the connection point between the second guide line and the second branch lead to be set on the center line of the long side of the rectangular area, and all electroplating PADs in a plating PAD group share the second branch lead, the setting method between the branch leads is simplified, interference between the designs of the second branch leads is avoided, and the production cost is further saved. Specifically, by setting an inclined second branch lead, the length of the first branch lead corresponding to each electroplating PAD can be made different. Since the resistance difference of the electroplating PAD itself can be compensated by the difference in the length of the corresponding first branch lead and the connection length of the second branch lead, the size design of all electroplating PADs and their corresponding branch leads in an electroplating PAD group is simplified, thereby more conveniently realizing the resistance balance design of the electroplating PAD in the group while saving the setting space as much as possible; at the same time, the second branch lead adopts an inclined routing method so that the transition is smoother when connecting the first branch lead, thereby improving the stability of the signal transmission process on the printed circuit board, reducing the loss, and optimizing the overall electrical performance of the printed circuit board.

[0012] This technical solution also provides a printed circuit board (PCB) having a conductive metal frame disposed along its edge. The conductive metal frame surrounds a rectangular surface without a metal layer. A plurality of electroplated pads (PADs) are disposed on the surface, and all of the plated pads are connected to the conductive metal frame via a lead assembly. The lead assembly is configured in accordance with the design method for balancing resistance between plated pads on a PCB provided in this technical solution, ensuring that the resistance of all plated pads on the PCB is equal to that of the conductive metal frame. By adjusting the lead assembly corresponding to the plated pads, the resistance of all plated pads on the PCB is equal to that of the conductive metal frame. This ensures that current is evenly distributed across the entire surface of the PCB during the electroplating process, improving the uniformity of electroplating across all plated pads on the PCB. Furthermore, all the electroplating PADs are grouped into a plurality of electroplating PAD groups according to the positions of the electroplating PADs on the printed circuit board. The lead group includes a first guide line and a second guide line for connecting the electroplating PAD group and the conductive metal frame, and a branch lead connecting all the electroplating PADs in the electroplating PAD group. The long sides and short sides of the rectangular area formed by the electroplating PAD group are arranged parallel to the edge lines of the board surface; The first guide line connects two opposite sides of the conductive metal frame and divides the board area of ​​the printed circuit board in a manner parallel to the edge line of the board surface.

[0013] In this technical solution, the rectangular area formed by the electroplated APD group is designed to be parallel to the rectangular board surface of the printed circuit board, and all the electroplated PAD groups on the board surface are adjacent to at least one first guide line; at the same time, the first guide line connects the two opposite sides of the conductive metal frame and divides the board surface area of ​​the printed circuit board in a manner parallel to the edge line of the board surface, which not only avoids the direct connection between the electroplated PAD and the conductive metal frame, reduces the edge effect of the surface of the printed circuit board, but also facilitates mutual planning and avoidance when setting the lead groups corresponding to the electroplated PAD, thereby simplifying the wiring method and wiring amount on the printed circuit board, improving the utilization rate of the printed circuit board board surface and saving production costs. Furthermore, by setting up a second guide line to further connect each electroplating PAD group and the first guide line, it is convenient to flexibly adjust the resistance difference between the electroplating PAD group and the first guide line located in different areas of the board surface by adjusting the size and setting method of the second guide line, thereby achieving resistance balance between groups; at the same time, in any electroplating PAD group, by adjusting the size and setting method of the branch lead corresponding to each electroplating PAD, the resistance difference between the electroplating PADs in the same group can be flexibly adjusted to achieve resistance balance within the group; through such a setting, while effectively achieving resistance balance between electroplating PADs, the lead setting method and size are simplified, thereby improving board surface utilization and saving production costs.

[0014] Preferably, in order to improve the setting independence of the electroplating PAD, avoid setting interference between leads, further simplify the setting method of leads on the printed circuit board, and improve the board surface utilization, in any electroplating PAD group, the connection point between the second guide line and the branch lead is located on the center line of the long side of the rectangular area, and the branch lead includes a first branch lead set perpendicular to the long side and a second branch lead set at an angle, and the resistance value of the branch lead corresponding to each electroplating PAD is equal.

[0015] Furthermore, the second guide line includes several vertical guide lines and several horizontal guide lines connected to each other, the vertical guide line is parallel to the first branch lead, and the horizontal guide line is arranged parallel to the long side of the rectangular area; the second guide line is connected to the branch lead, the first guide line and the conductive metal frame through the vertical guide line.

[0016] In the present technical solution, in order to keep the resistance of each electroplated PAD in different electroplated PAD groups consistent with the conductive metal frame, the difference between each electroplated PAD group due to the corresponding first guide line and the electroplated PAD group's own resistance and the conductive metal frame's resistance is compensated by the second guide line. By changing the setting length and width of the second guide line, the second guide line can be conveniently adjusted to the required resistance. In order to reduce the wiring size of the lead group on the printed circuit board and improve the board utilization rate, the second guide line can adopt a bent lead, specifically, including a plurality of vertical guide lines and a plurality of horizontal guide lines connected to each other, and the vertical guide line is parallel to the first branch lead, and the horizontal guide line is arranged parallel to the long side of the rectangular area. The second guide line is connected to the branch lead, the first guide line and the conductive metal frame through the vertical guide line, so that the overall setting length of the second guide line is extended as much as possible in the limited plane space size, thereby effectively achieving resistance balance between electroplated PADs and improving the electroplating uniformity of the electroplated PAD on the board surface, while further simplifying the lead setting method and size. Preferably, the gap between the transverse guide lines is not less than 30 μm, which reduces the production process requirements for the circuits and ensures the overall production precision of the second guide lines.

[0017] Preferably, the metal plating layer on the electroplating PAD is one or more of gold, silver, nickel, tin, and copper, and the branch leads, the first guide wires, and the second guide wires are all made of copper.

[0018] Preferably, the thickness of the metal plating layer on the electroplating PAD is not less than 0.01 μm.

[0019] Compared with the prior art, the present invention has the following beneficial effects: 1. By grouping all the electroplated PADs on the surface of the printed circuit board according to their areas on the board surface, the electroplated PADs are grouped according to their positions on the printed circuit board to form several electroplated PAD groups, thereby facilitating the planning of the positions of the first guide lines set on the board surface of the printed circuit board and connected to the conductive metal frame, so that all electroplated PAD groups are adjacent to at least one first guide line, so that the leads connecting the electroplated PADs to the first guide lines can be designed more freely, which not only avoids mutual interference between the leads of adjacent electroplated PADs, but also reduces the laying area and setting distance of the leads, simplifies the layout and size of the leads, and ensures the tolerance and reliability of the signal transmission layout on the printed circuit board; at the same time, the conductive metal frame and the adjacent electroplated PADs are separated by the first guide line, which greatly reduces the edge effect on the printed circuit board and improves the electrical precision and reliability of the printed circuit board.

[0020] 2. In any electroplating PAD group, the electroplating PAD group is connected to the first guide line adjacent to it through the second guide line, and each electroplating PAD in the group is connected to one end of the second guide line through its corresponding branch lead, so that the resistance of all electroplated PADs on the printed circuit board is the same as the resistance of the conductive metal frame. The leads of the electroplated metal PAD are designed between groups and within groups. By setting a second guide line to connect the electroplating PAD group and the first guide line adjacent to it, and by making all the electroplated PADs in the group connected to the first guide line with their corresponding branch leads, the resistance value difference of several electroplated PADs included in the electroplating PAD group is compressed to the setting of the branch lead, thereby effectively achieving resistance balance between electroplating PADs and simplifying the lead setting method and size, thereby improving the electroplating uniformity of all electroplated PADs on the surface of the printed circuit board while simplifying the metal layer design of the printed circuit board surface, improving the board surface utilization rate, and saving production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a flow chart of a design method for resistance balancing between electroplated PADs on a printed circuit board provided by the present invention.

[0022] Figure 2 This is a schematic structural diagram of the printed circuit board provided by the present invention.

[0023] Figure 3 This is a structural schematic diagram of the electroplated PAD group and lead group on the printed circuit board provided by the present invention.

[0024] Figure 4 This is a schematic structural diagram of the electroplated PAD group and lead group on the printed circuit board provided in Example 3.

[0025] Figure 5 Comparative Example 1 provides a schematic structural diagram of the electroplated PAD group and the traditional lead group on the printed circuit board.

[0026] Description of the drawings: conductive metal frame 10, board surface 20, electroplated PAD group 30, lead group 40, electroplated PAD 100, first guide line 210, second guide line 220, first branch lead 230, second branch lead 240. DETAILED DESCRIPTION

[0027] The accompanying drawings are for illustrative purposes only and are not to be construed as limiting the present invention. To better illustrate the following embodiments, some components in the accompanying drawings may be omitted, enlarged, or reduced in size, and do not represent actual product dimensions. Those skilled in the art will appreciate that some well-known structures and their descriptions may be omitted from the accompanying drawings.

[0028] Example 1 like Figure 1-Figure 2As shown, this embodiment provides a design method for balancing resistance between electroplated PADs 100 on a printed circuit board. A conductive metal frame 10 is provided along the edge of the printed circuit board. A plurality of electroplated PADs 100 are provided on a surface 20 of the printed circuit board. The electroplated PADs 100 are connected to the conductive metal frame via corresponding leads. The design method includes the following steps: S1. The electroplating PAD100 is grouped according to the position of the electroplating PAD100 on the printed circuit board to form a plurality of electroplating PAD groups 30; the electroplating PAD group 30 forms a rectangular area having a long side and a short side, and the electroplating PAD100 is arranged in the direction of the long side in the group interval; S2. A plurality of first guide lines 210 are provided to separate all the electroplating PAD groups 30 provided on the board surface 20. The first guide lines 210 are provided on the board surface 20 of the printed circuit board and connected to the conductive metal frame 10 so that all the electroplating PAD groups 30 are adjacent to at least one first guide line 210. S3. In any electroplating PAD group 30, the electroplating PAD group 30 is connected to the first guide line 210 adjacent to it through the second guide line 220, and each electroplating PAD100 in the group is connected to one end of the second guide line 220 through its corresponding branch lead, so that the resistance of all electroplating PAD100 and its corresponding leads on the printed circuit board is the same as the resistance of the conductive metal frame 10.

[0029] Specifically, the inter-group design of the leads of the electroplated metal PAD on the printed circuit board is performed by grouping and setting the first guide line 210 and the second guide line 220, and the intra-group design of the leads is further realized by the branch leads correspondingly connected to the electroplated PAD100. The resistance values ​​of all the electroplated PAD100 on the printed circuit board and the conductive metal frame 10 are made consistent through the adjustment of the leads, which effectively achieves the resistance balance between all the electroplated PAD100 on the printed circuit board while simplifying the lead setting method and size. While improving the electroplating uniformity of all the electroplated PAD100 on the surface of the printed circuit board, it also simplifies the metal layer design of the printed circuit board surface 20, thereby improving the board surface utilization and saving production costs.

[0030] Furthermore, in any electroplating PAD group 30, the length and width of the branch lead corresponding to the electroplating PAD100 are changed according to the position of the electroplating PAD100 between the groups, so that the resistance value from each electroplating PAD100 to the second guide line 220 is equal, and by changing the setting length and width of the second guide line 220, the resistance of all electroplating PAD100 in each electroplating PAD group 30 and the conductive metal frame 10 is the same. In the present technical solution, the electroplating PAD group 30 is connected to the first guide line 210 adjacent to it through the second guide line 220, and all the electroplating PADs 100 in the group are connected to the first guide line 210 with their corresponding branch leads. Since the resistance value difference of the several electroplating PADs 100 included in the electroplating PAD group 30 is compressed to the setting of the branch leads corresponding to the electroplating PADs 100, between different electroplating PAD groups 30, since the length and resistance value of the first guide line 210 when located in different areas of the board surface 20 are determined by design, the resistance value of each electroplating PAD 100 in the group is also determined by design. In order to maintain The resistance of each electroplated PAD100 in different electroplated PAD groups 30 is consistent with the conductive metal frame 10. The difference between each electroplated PAD group 30 due to the corresponding first guide line 210 and the electroplated PAD group 30's own resistance and the conductive metal frame 10 is compensated by the second guide line 220. By changing the setting length and width of the second guide line 220, the second guide line 220 can be conveniently adjusted to the required resistance, thereby effectively achieving resistance balance between the electroplated PAD100 and improving the electroplating uniformity of the electroplated PAD100 on the board surface 20, while further simplifying the lead setting method and size.

[0031] Furthermore, in any electroplating PAD group 30, the branch leads include a first branch lead 230 perpendicular to the long side and correspondingly connected to one electroplating PAD 100, and a second branch lead 240 connecting the first branch lead 230 and the second guide line 220. In this technical solution, since the electroplating PAD group 30 forms a rectangular area, in order to avoid mutual influence between adjacent electroplating PADs 100, the branch leads connecting each electroplating PAD 100 in the group include a first branch lead 230 perpendicular to the long side and correspondingly connected to one electroplating PAD 100, and a second branch lead 240 connecting the first branch lead 230 and the second guide line 220. The first branch lead 230 ensures mutual isolation and independence between the electroplating PADs 100, and the size and position of the second branch lead 240 are set to achieve resistance balance design for the electroplating PADs 100 in the group.

[0032] Preferably, in any electroplating PAD group 30, the connection point between the second guide line 220 and the second branch lead 240 is set on the center line of the long side of the rectangular area. An inclined second branch lead 240 is provided on each side of the second guide line 220. The first branch lead 230 is connected to a corresponding electroplating PAD 100 and further connected to the second branch lead 240. The inclination angle and width of the second branch lead 240 are determined by the resistance values ​​of the electroplating PAD 100 located on the center line of the long side of the rectangular area and the two electroplating PADs 100 at both ends. By setting the connection point between the second guide line 220 and the second branch lead 240 on the center line of the long side of the rectangular area, and all electroplating PADs 100 in a electroplating PAD group 30 share the second branch lead 240, the arrangement of the branch leads is simplified, interference between the designs of the second branch leads 240 is avoided, and manufacturing costs are further reduced. Specifically, by setting an inclined second branch lead 240, the length of the first branch lead 230 corresponding to each electroplating PAD100 can be made different. Since the resistance difference of the electroplating PAD100 itself can be compensated by the difference in the length of the corresponding first branch lead 230 and the connection length of the second branch lead 240, the size design of all electroplating PAD100 and its corresponding branch leads in an electroplating PAD group 30 is simplified, thereby more conveniently realizing the resistance balance design of the electroplating PAD100 in the group while saving the setting space as much as possible; at the same time, the second branch lead 240 adopts an inclined routing method so that the transition is smoother when connecting to the first branch lead 230, thereby improving the stability of the signal transmission process on the printed circuit board, reducing the loss, and optimizing the overall electrical performance of the printed circuit board.

[0033] Example 2 like Figure 2-Figure 3 As shown, this embodiment provides a printed circuit board, wherein a conductive metal frame 10 is provided on the edge of the printed circuit board. The conductive metal frame 10 is provided around a rectangular board surface 20 without a metal layer. A plurality of electroplated PADs 100 are provided on the board surface 20, and all of the electroplated PADs 100 are connected to the conductive metal frame 10 via a lead group 40. The lead group 40 is provided in accordance with the design method for balancing the resistance between the electroplated PADs 100 on the printed circuit board provided in the technical solution, and the resistance of all the electroplated PADs 100 on the printed circuit board is equal to the resistance of the conductive metal frame 10. By adjusting the lead group 40 corresponding to the electroplated PADs 100, the resistance of all the electroplated PADs 100 on the printed circuit board is equal to the resistance of the conductive metal frame 10, thereby ensuring that the current is evenly distributed over the entire surface of the printed circuit board during the electroplating process, thereby improving the uniformity of the electroplating of all the electroplated PADs 100 on the printed circuit board.

[0034] Furthermore, all the plating PADs 100 are grouped into several plating PAD groups 30 based on their placement on the printed circuit board. The lead group 40 includes a first guide wire 210 and a second guide wire 220 for connecting the plating PAD group 30 to the conductive metal frame 10, as well as branch leads connecting all the plating PADs 100 in the plating PAD group 30. The long and short sides of the rectangular area formed by the plating PAD group 30 are parallel to the edge of the board surface 20. The first guide wire 210 connects two opposite sides of the conductive metal frame 10 and divides the board surface 20 of the printed circuit board in a manner parallel to the edge of the board surface 20. By connecting the plating PAD group 30 to the first guide wire 210, direct connection between the plating PAD 100 and the conductive metal frame is avoided, reducing edge effects on the printed circuit board surface, and simplifying the wiring method and wiring on the printed circuit board. Furthermore, by setting up a second guide line 220 to further connect each electroplating PAD group 30 and the first guide line 210, it is convenient to flexibly adjust the resistance difference between the electroplating PAD group 30 and the first guide line 210 located in different areas of the board surface 20 by adjusting the size and setting method of the second guide line 220, thereby achieving resistance balance between groups; at the same time, in any electroplating PAD group 30, by adjusting the size and setting method of the branch lead set corresponding to each electroplating PAD100, the resistance difference between the electroplating PAD100 in the same group can be flexibly adjusted to achieve resistance balance within the group; through such a setting, while effectively achieving resistance balance between the electroplating PAD100, the lead setting method and size are simplified, thereby improving board surface utilization and saving production costs.

[0035] Preferably, in order to improve the setting independence of the electroplating PAD100, avoid setting interference between leads, further simplify the setting method of the leads on the printed circuit board, and improve the utilization rate of the board surface 20, in any electroplating PAD group 30, the connection point between the second guide line 220 and the branch lead is located on the center line of the long side of the rectangular area, and the branch lead includes a first branch lead 230 set perpendicular to the long side and a second branch lead 240 set at an angle, and the resistance value of the branch lead corresponding to each electroplating PAD100 is equal.

[0036] Furthermore, in order to keep the resistance of each electroplated PAD 100 in each electroplated PAD group 30 consistent with the conductive metal frame 10, the difference between the resistance of the corresponding first guide wire 210 and the electroplated PAD group 30 and the resistance of the conductive metal frame 10 is compensated by the second guide wire 220. By changing the setting length and width of the second guide wire 220, the second guide wire 220 can be easily adjusted to the required resistance. In order to reduce the wiring size of the lead group 40 on the printed circuit board and improve the utilization rate of the board surface 20, the second guide wire 220 can be a bent lead. Specifically, the system comprises a plurality of interconnected vertical guide lines and a plurality of horizontal guide lines, wherein the vertical guide lines are parallel to the first branch lead 230, and the horizontal guide lines are arranged parallel to the long sides of the rectangular area. Furthermore, the second guide line 220 is connected to the branch lead, the first guide line 210, and the conductive metal frame 10 via the vertical guide lines. This allows the overall length of the second guide line 220 to be extended as much as possible within the limited planar space. This effectively achieves resistance balance between the electroplated PADs 100 and improves the uniformity of electroplating of the PADs 100 on the board 20, while further simplifying the arrangement and size of the leads. Preferably, the gap between the horizontal guide lines is no less than 300 μm, which reduces the requirements for the circuit manufacturing process and ensures the precision of the overall manufacturing of the second guide line 220.

[0037] Preferably, the metal plating layer on the electroplated PAD 100 is one or more of gold, silver, nickel, tin, and copper, and the branch leads, the first guide wires 210 , and the second guide wires 220 are all made of copper.

[0038] Preferably, the thickness of the metal plating layer on the electroplating PAD 100 is not less than 0.010 μm.

[0039] Example 3 like Figure 3 As shown, this embodiment also provides a printed circuit board, which differs from Example 2 in that, for the lead group connected to the electroplating PAD, in any electroplating PAD group, the connection point between the second guide line and the branch lead is located on the center line of the long side of the rectangular area, and the branch lead includes a first branch lead arranged perpendicular to the long side and a second branch lead arranged obliquely, and an inclined second branch lead is provided on both sides of the second guide line. The first branch lead is correspondingly connected to an electroplating PAD and further connected to the second branch lead; the inclination angle and width of the second branch lead are determined by the resistance value of the electroplating PAD located on the center line of the long side of the rectangular area and the two electroplating PADs at both ends.

[0040] Specifically, for this lead group, by changing the connection method between the plating PAD and the second guide line, the resistance value from each plating PAD in the group to the second guide line can be made equal, achieving resistance balance within the plating PAD group. The calculation method is as follows: like Figure 4 As shown, A1 is the first guide line, L1 is the length of the second branch lead, L2 is the length of the first branch lead connected to the non-edge electroplating PAD in the group increased from L3, L3 is the length of the first branch lead between the electroplating PAD at the edge of the group and the second guide line, T1 is the second guide line, T2 is the second branch lead, T3 is the first branch lead, T4 is the electroplating PAD, W1 is the width of the first branch lead, and W2 is the width of the second branch lead; The resistance calculation formula is known as: R = ρL / S = ρL / WH (Formula 1), For a given printed circuit board, the width W1 of the first branch lead T3 is a constant, the copper thickness H is a constant, the angle θ of the second branch lead is a constant, and the gap X between adjacent electroplated pads is a constant. From this, we can see that, starting from the middle electroplated pad, with each electroplated pad moved left or right, the length of L1 decreases by 1 unit, and the length of L2 increases by 1 unit. Using the following formula, we can adjust the width W2 of the diagonal conductive line so that the resistance reduction of L1 equals the resistance increase of L2. This will ensure equal resistance from each finger to the conductive position.

[0041] R L1减 =R L2增 =ρL 1减 / W1*h =ρL 2增 / W2*h, that is, W2=W1*L 2增 / L 1减 (Equation 2) sinθ=L 1减 / L 2增 , that is, L 2增 / L 1减 =1 / sinθ (Formula 3) Substituting the above equation 3 into equation 2 yields W2=W1 / sinθ. The angle θ and W1 are both constants. Combined with equation 1, the width of W2 can be calculated, which means that the resistance from each electroplated PAD in the group to the second guide line can be equal.

[0042] Example 4 like Figure 4 As shown, this embodiment is a verification process for the resistance balancing effect between the plated PADs after the lead group is used on the printed circuit board provided in Example 3, which is specifically as follows: According to the product design information, the electroplated PAD is a gold finger with a gold coating. The lead group is made of copper, and the copper thickness is equal to H = 0.055mm. According to the product information, the length of L1 is measured to be 6mm, the length of the second branch lead L2 is 41mm, and X = 8.1mm. According to internal design rules, the width W1 of L1 is determined to be 0.2mm. 1. Perform balance adjustment calculation on the electroplating PADs within the electroplating PAD group: According to the known conditions, R can be calculated L1 (ρ—resistivity of copper at room temperature: 0.0175mohm*mm): R L1 =ρL1 / H*W1=0.0175mohm*mm*6mm / 0.055mm*0.2mm=9.5mohm; In order to make R L1 =R L2 , W2 can be directly calculated based on the resistance using the formula: W2=ρL2 / H* R L2 =0.0175mohm*mm *41mm / 0.055mm*9.5mohm=1.37mm; That is, the adjustment width of W2 is 1.37 mm.

[0043] 2. Combine the above calculation results with the product information and the theoretical formula to obtain the results for matching verification: According to the known product specification information, the inclination angle of the second branch lead can be calculated as θ≈8.33° W2=W1 / sinθ=0.2mm / sin(8.33°)=1.38mm, the results are consistent.

[0044] 3. Verify whether the change in the first lead between adjacent electroplating PADs within the group is consistent with the change in the second lead: Knowing the angle θ and W2, we can calculate R L2增 and R L1减 : L 1减 =tanθ*X=0.146*8.1=1.19mm; L 2增 =L1 / sinθ=1.19 / 0.828=8.21mm; R L1减 =ρ*L 1减 / W1*H=(0.0175*1.19) / (0.2*0.055)=1.89mohm; R L2增 =ρ*L 2增 / W2*H=(0.0175*8.21) / (1.37*0.055)=1.90mohm; From the calculation results, we can know that R L2增 Equal to RL 1减 .

[0045] 4. Verify that the resistance from each electroplating PAD to the first guide line in the group is the same: like Figure 4 As shown, each electroplating PAD is numbered starting from the middle, and is marked as 1, 2, 3, 4, 5, and 6 from the center to one end; the point where the entire group of electroplating PADs is connected to the main lead is marked as point o, and the resistance of each electroplating PAD from point o is calculated and optimized.

[0046] R L3 =ρ*L3 / W1*H=(0.0175*2) / (0.2*0.055)=3.18mohm The resistance of the first and second guide wires connecting the electroplating PADs between groups is consistent for the entire group of electroplating PADs. Taking the actual design data into the calculation, we can get: R T1 =ρ*L T1 / W T1 *H=(0.0175*84) / (0.5*0.055)=53.45mohm; The resistance value from each electroplated PAD to point o is calculated as follows R1=R L3 +R L1 +R T1 ; R2=R L3 +R L1 -1*R L1减 +1*R L2增 +R T1 ; R3= R L3 +R L1 -2*R L1减 +2*R L2增 +R T1 ; R4= R L3 +R L1 -3*R L1减 +3*R L2增 +R T1 ; R5= R L3 +R L1 -4*R L1减 +4*R L2增 +R T1 ; R6= RL3 +R L1 -5*R L1减 +5*R L2增 +R T1 ; Substitute the data and calculate the final result: R1=R2=R4=R5=R6=66.13mohm.

[0047] It can be seen from this that when this lead group is used, it can be ensured that the resistance of each electroplated PAD in each electroplated PAD group on the printed circuit board is balanced.

[0048] Comparative Example 1 This comparative example also provides a printed circuit board, which is different from Examples 3 and 4 in that the electroplated PAD on this printed circuit board adopts the following method: Figure 5 The conventional lead group shown is connected to the conductive metal frame. Specifically, the electroplated PAD is connected to the main lead (equivalent to the first lead in the present invention) through a secondary lead of equal length.

[0049] The printed circuit board provided in this comparative example and the printed circuit board provided in Example 3 were subjected to an electroplating gold process according to the same process parameters, so that all the electroplated PADs on the printed circuit board were covered with a gold plating layer. The thickness of the gold plating on the two printed circuit boards was collected and the thickness uniformity of the gold plating within the group and the entire board was analyzed to obtain the following table:

[0050] It can be seen that compared with the printed circuit board provided in Comparative Example 1, when the lead group provided in Example 3 is used to connect the electroplated PAD on the printed circuit board, the average coating thickness of the entire electroplated PAD on the printed circuit board increases and is closer to the preset coating thickness, indicating that the electroplating efficiency is increased in the electroplating gold process; at the same time, the variance of the coating thickness of all electroplated PADs on the entire printed circuit board is small, and the overall range within each electroplated PAD group on the board surface is reduced, indicating that the difference in coating thickness of all electroplated PADs on the printed circuit board is small, that is, the electroplating uniformity of all electroplated PADs on the printed circuit board is greatly improved.

[0051] Obviously, the above embodiments of the present invention are merely examples for the purpose of clearly illustrating the technical solutions of the present invention, and are not intended to limit the specific implementation methods of the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the claims of the present invention shall be included within the scope of protection of the claims of the present invention.

Claims

1. A design method for balancing resistance between electroplated PADs on a printed circuit board, wherein a conductive metal frame is provided along the edge of the printed circuit board, and a plurality of electroplated PADs are provided on the surface of the printed circuit board, wherein the electroplated PADs are connected to the conductive metal frame through corresponding leads, wherein: The design method comprises the following steps: S1. The electroplating PADs are grouped according to the positions of the electroplating PADs on the printed circuit board to form a plurality of electroplating PAD groups; the electroplating PAD groups form a rectangular area, the rectangular area having a long side and a short side, and the direction in which the electroplating PADs are arranged in the group intervals is the direction of the long side; S2. Setting a plurality of first guide lines to separate all the electroplated PAD groups arranged on the board surface, wherein the first guide lines are arranged on the board surface of the printed circuit board and connected to the conductive metal frame, so that all the electroplated PAD groups are adjacent to at least one first guide line; S3. In any electroplated PAD group, the electroplated PAD group is connected to the first guide line adjacent to it through the second guide line, and each electroplated PAD in the group is connected to one end of the second guide line through its corresponding branch lead, so that the resistance of all electroplated PADs on the printed circuit board and their corresponding leads is the same as the resistance of the conductive metal frame.

2. The design method according to claim 1, characterized in that: In any electroplated PAD group, the length and width of the branch lead corresponding to the electroplated PAD are changed according to the position of the electroplated PAD between the groups, so that the resistance value from each electroplated PAD to the second guide line is equal, and the setting length and width of the second guide line are changed to make the resistance of all electroplated PADs in each electroplated PAD group and the conductive metal frame the same.

3. The design method according to claim 2, characterized in that: In any electroplating PAD group, the branch leads include a first branch lead perpendicular to the long side and correspondingly connected to one electroplating PAD, and a second branch lead connecting the first branch lead and the second guide line.

4. The design method according to claim 3, characterized in that: In any one of the electroplating PAD groups, the connection point between the second guide line and the second branch lead is arranged on the center line of the long side of the rectangular area, an inclined second branch lead is arranged on both sides of the second guide line, and the first branch lead is correspondingly connected to one electroplating PAD and further connected to the second branch lead; The inclination angle and width of the second branch lead are determined by the resistance values ​​of the electroplated PAD located on the center line of the long side of the rectangular area and the two electroplated PADs at both ends.

5. A printed circuit board, wherein a conductive metal frame is provided at the edge of the printed circuit board, the conductive metal frame is provided around a rectangular board surface without a metal layer, a plurality of electroplated PADs are provided on the board surface, and all the electroplated PADs are connected to the conductive metal frame through a lead group, characterized in that: The lead group is arranged according to the design method for balancing the resistance between the plated PADs on the printed circuit board according to any one of claims 1 to 4, and makes the resistance of all the plated PADs on the printed circuit board the same as the resistance of the conductive metal frame.

6. The printed circuit board according to claim 5, characterized in that: All the electroplating PADs are grouped into a plurality of electroplating PAD groups according to the positions of the electroplating PADs on the printed circuit board, wherein the lead group includes a first guide line and a second guide line for connecting the electroplating PAD group and the conductive metal frame, and a branch lead connecting all the electroplating PADs in the electroplating PAD group; The long sides and short sides of the rectangular area formed by the electroplating PAD group are arranged parallel to the edge lines of the board surface; The first guide line connects two opposite sides of the conductive metal frame and divides the board area of ​​the printed circuit board in a manner parallel to the edge line of the board surface.

7. The printed circuit board according to claim 6, characterized in that: In any electroplated PAD group, the connection point between the second guide line and the branch lead is located on the center line of the long side in the rectangular area. The branch lead includes a first branch lead arranged perpendicular to the long side and a second branch lead arranged obliquely. The resistance values ​​of the branch leads corresponding to each electroplated PAD are equal.

8. The printed circuit board according to claim 7, characterized in that: The second guide line includes a plurality of vertical guide lines and a plurality of horizontal guide lines that are interconnected, the vertical guide line is parallel to the first branch lead, and the horizontal guide line is arranged parallel to the long side of the rectangular area; the second guide line is connected to the branch lead, the first guide line and the conductive metal frame through the vertical guide line.

9. The printed circuit board according to any one of claims 5 to 8, characterized in that: The metal plating layer on the electroplated PAD is one or more of gold, silver, nickel, tin, and copper, and the branch leads, the first guide wires, and the second guide wires are all made of copper.

10. The printed circuit board according to claim 9, characterized in that: The thickness of the metal plating layer on the electroplating PAD is not less than 0.01 μm.

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