Circuit board manufacturing method based on thick copper plate inner pull lead and circuit board
Patent Information
- Application Number
- CN202611324478.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-08-28
- Publication Date
- 2026-10-09
AI Technical Summary
[0005]然而，采用内拉引线的方式进行电镀可以有效解决以上电流密度不足，镀层薄且不均，但却引来了另一问题，这种内拉引线在蚀刻时，其根部不容易蚀刻，容易残留，形成短路隐患
[0017]上述基于厚铜板内拉引线的电路板制作方法和电路板，由于基板在导电引线的根部的两侧设置泄流槽，使得蚀刻液能够充分流通至导电引线的根部，并且随着蚀刻液的流动，在泄流槽周围形成激流、漩涡，从而使得导电引线的根部得到充分蚀刻，从而充分消除导电引线。
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Figure CN122892104A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of circuit board manufacturing technology, and in particular to a method for manufacturing a circuit board based on internally drawn leads in a thick copper plate and the circuit board itself. Background Technology
[0002] Thick copper circuit boards (copper thickness ≥ 3 oz, typically 6~12 oz) are widely used in high-current power modules, automotive electronics, industrial control, and communication base stations. To meet the requirements of local contact reliability, plug-in resistance, and signal transmission, gold plating (hard gold or soft gold) is often required in specific areas, such as gold fingers, button contacts, and connector pads.
[0003] When a PCB (Printed Circuit Board) needs to be selectively gold-plated in specific localized areas, thicker boards, substrates, and copper layers are typically required. Traditional edge-conducting processes cannot meet the uniformity requirements of localized gold plating. With traditional edge-conducting, the current is diverted by the large copper layer, resulting in insufficient current density in the target gold-plating area. The plating thickness is much lower than in the center area, and the edges are prone to scorching, failing to meet the gold thickness uniformity requirements.
[0004] Because the large copper surface of thick copper plates has extremely high conductivity, if conventional edge-lead electroplating is used, the current is easily diverted by the large copper surface, resulting in insufficient current density in the target gold plating area and a thin and uneven plating layer. Therefore, the industry often uses internal lead technology—that is, setting independent, etchable conductive leads inside the board to directly guide the current from the board edge or process edge to the area to be gold plated, achieving precise electroplating.
[0005] However, while electroplating with internally pulled leads can effectively solve the problems of insufficient current density and thin, uneven plating, it introduces another issue: the roots of these internally pulled leads are not easily etched during etching, leaving residues that could lead to short circuits. Summary of the Invention
[0006] In view of this, it is necessary to provide a method for manufacturing a circuit board based on internally drawn leads in a thick copper plate and a circuit board.
[0007] On the one hand, a method for manufacturing a circuit board based on internally pulled leads in a thick copper plate is provided, including: A pre-fabricated circuit board is provided, wherein the circuit board includes a substrate and a thick copper circuit layer disposed on the substrate and a plurality of conductive leads connected to a predetermined area of the thick copper circuit layer, wherein at least one of the conductive leads is connected to the thick copper circuit layer and the two sides of the connection position are drainage areas, and the substrate is provided with drainage grooves in the drainage areas. A first film is obtained by coating the surface of the circuit board. The first film is then exposed and developed to expose a predetermined area of the thick copper circuit layer. Using the conductive leads to conduct electricity, a predetermined area of the thick copper circuit layer is electroplated to form an electroplated layer on the surface of the predetermined area of the thick copper circuit layer. Remove the first coating from the surface of the circuit board; A second film is applied to the surface of the circuit board to obtain a second film. The second film is then exposed and developed to expose the conductive leads. The conductive leads are etched, and after etching, the second coating is removed to obtain a thick copper circuit board.
[0008] In one embodiment, the conductive lead is curved on both sides of the connection point with the thick copper circuit layer.
[0009] In one embodiment, the step of etching the conductive leads includes: The conductive lead is etched once using an etching solution of a first preset concentration; After the first etching, a second preset concentration of etching solution is used to perform a high-pressure spray on the position where the conductive lead is connected to the thick copper circuit layer for a second etching, wherein the first preset concentration is greater than the second preset concentration.
[0010] In one embodiment, at least one of the conductive leads includes a main lead and a plurality of branch leads, one end of the main lead is connected to each of the branch leads via a bridging wire, and each of the branch leads is connected to the thick copper circuit layer.
[0011] In one embodiment, each of the conductive leads is configured to be at least one of the following: The spacing between adjacent conductive leads is greater than or equal to 6 mil; The width of the conductive lead is greater than 8 mil; The distance between each of the conductive leads and the nearest thick copper circuit layer is greater than or equal to 40 mil.
[0012] In one embodiment, the step of coating the surface of the circuit board to obtain a first coating, and exposing and developing the first coating to expose a predetermined area of the thick copper circuit layer includes: A laminating machine is used to coat and press the surface of the circuit board, and the coating in the leakage area is re-pressed to obtain a first coating, wherein the first coating is at least partially inserted into the leakage groove. The first coating is exposed and developed to expose a predetermined area of the thick copper circuit layer, and the first coating at least covers the leakage area.
[0013] In one embodiment, the step of coating the surface of the circuit board to obtain a second coating includes: The surface of the preset area of the thick copper circuit layer is roughened; After roughening the preset area of the thick copper circuit layer, a second coating is applied to the surface of the circuit board to obtain a second coating.
[0014] In one embodiment, after the step of roughening the surface of the predetermined region of the thick copper circuit layer, the method further includes: The surface of the thick copper circuit layer is cleaned.
[0015] In one embodiment, the step of etching the conductive leads, and then removing the second coating to obtain a thick copper circuit board includes: The conductive leads are etched, and after etching, the second coating is removed. The surface of the circuit board is coated with solder resist ink to form a solder joint layer. The solder joint layer is then opened to expose the pads, resulting in a thick copper circuit board.
[0016] A circuit board is manufactured using the circuit board fabrication method based on thick copper plate internal lead wires as described in any of the above embodiments.
[0017] The above-mentioned circuit board manufacturing method and circuit board based on thick copper plate internal lead wires, because the substrate is provided with drainage grooves on both sides of the root of the conductive lead wire, the etching solution can be fully circulated to the root of the conductive lead wire, and as the etching solution flows, a torrent and vortex are formed around the drainage groove, so that the root of the conductive lead wire is fully etched, thereby fully eliminating the conductive lead wire. Attached Figure Description
[0018] Figure 1 This is a schematic flowchart of a circuit board fabrication method based on internally pulled leads on a thick copper plate, as shown in one embodiment.
[0019] Figure 2 This is a partial cross-sectional view of the circuit board in one embodiment; Figure 3 This is a partial planar structural diagram of a circuit board in one embodiment.
[0020] Explanation of reference numerals in the attached figures: 100. Circuit board; 200. Substrate; 210. Thick copper circuit layer; 220. Conductive lead; 221. Main lead; 222. Branch lead; 223. Bridging wire; 201. Drainage channel; Detailed Implementation
[0021] Preferred embodiments of the present application will now be described in more detail with reference to the accompanying drawings. While preferred embodiments of the present application are shown in the drawings, it should be understood that the present application may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to make the present application more thorough and complete, and to fully convey the scope of the present application to those skilled in the art.
[0022] The terminology used in this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. The singular forms “a,” “the,” and “the” used in this application and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.
[0023] It should be understood that although the terms "first," "second," "third," etc., may be used in this application to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this application, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.
[0024] In one embodiment, such as Figure 1 As shown, a method for manufacturing a circuit board based on internally pulled leads in a thick copper plate is provided, which includes: Step 110: Provide a pre-fabricated circuit board, wherein the circuit board includes a substrate and a thick copper circuit layer disposed on the substrate and a plurality of conductive leads connected to a predetermined area of the thick copper circuit layer, and at least one of the conductive leads is connected to the thick copper circuit layer at a location on both sides of a current-draining area, and the substrate has a current-draining groove formed in the current-draining area.
[0025] In this embodiment, as Figure 2 and Figure 3As shown, a circuit board 100 with a pre-fabricated thick copper circuit layer 210 and conductive leads 220 is provided. The substrate 200 is an insulating substrate 200. The thick copper circuit layer 210 is a circuit layer with a circuit pattern disposed on the substrate 200. The thick copper circuit layer 210 is pre-fabricated on the substrate 200 before step 110. The thickness of the thick copper circuit layer 210 is greater than or equal to 3 oz, for example, the thickness of the thick copper circuit layer 210 is 6~12 oz. The theoretical thickness of 1 oz copper foil is approximately 35 μm. In this embodiment, the preset area of the thick copper circuit layer 210 is the area to be electroplated. The conductive leads 220 are electrically connected to the preset area. Thus, when an external electroplating power supply is connected, the conductive leads 220 guide the electricity of the electroplating power supply to the preset area of the thick copper circuit layer 210, so that the preset area is electroplated.
[0026] In this embodiment, the conductive leads 220 are set using an internal pull-in method, meaning the conductive leads 220 are located inside the circuit board 100. Independent, etchable conductive leads 220 are provided within the board, directly guiding current from the board edge or process edge into the area to be plated, achieving precise electroplating. The end of the conductive lead 220 directly connected to the thick copper circuit layer 210 is the root of the conductive lead 220. Drainage areas are provided on both sides of the root of some or all of the conductive leads 220, and drainage grooves 201 are formed in the drainage areas of the substrate 200.
[0027] In one embodiment, prior to step 110, a circuit board 100 with a thick copper circuit layer 210 is provided. Based on the circuit pattern, a laser is used to cut the bleed area on both sides of the location where at least one of the conductive leads 220 is connected to the thick copper circuit layer 210 to obtain a bleed groove 201.
[0028] Step 120: Apply a film to the surface of the circuit board to obtain a first film. Expose and develop the first film to expose a preset area of the thick copper circuit layer.
[0029] In this embodiment, the first coating can be a dry film or a wet film. The first coating is used to protect the parts of the circuit board 100 that do not need to be electroplated, especially the conductive leads 220. The preset area of the exposed thick copper circuit layer 210 is the electroplating area.
[0030] Step 130: Using the conductive leads to conduct electricity, electroplating is performed on a preset area of the thick copper circuit layer to form an electroplated layer on the surface of the preset area of the thick copper circuit layer.
[0031] In this embodiment, an external electroplating power supply is used to conduct electricity to a predetermined area of the thick copper circuit layer 210 through conductive leads 220, so that an electroplating layer is formed on the surface of the predetermined area.
[0032] Step 140: Remove the first coating from the surface of the circuit board.
[0033] In this step, a stripping process is used to remove the first coating on the surface of the circuit board 100.
[0034] Step 150: Apply a film to the surface of the circuit board to obtain a second film, and expose and develop the second film to expose the conductive leads.
[0035] In this embodiment, the second coating can be a dry film or a wet film. The second coating is used to protect the circuit layers on the circuit board 100 that do not need to be etched, so that the exposed conductive leads 220 can be etched.
[0036] Step 160: Etch the conductive leads. After etching the conductive leads, remove the second coating to obtain a thick copper circuit board.
[0037] In this embodiment, the conductive lead 220 is etched to remove the conductive lead 220 from the circuit board 100. It is worth noting that, because drainage grooves 201 are provided on both sides of the root of the conductive lead 220, the etching solution can flow sufficiently to the root of the conductive lead 220. Furthermore, as the etching solution flows, a rapid current and vortex are formed around the drainage grooves 201, thereby ensuring that the root of the conductive lead 220 is fully etched, effectively preventing etching residue at the root of the conductive lead 220, and thus completely eliminating the conductive lead 220.
[0038] In the above embodiment, since the substrate 200 provides drainage grooves 201 on both sides of the root of the conductive lead 220, the etching solution can flow fully to the root of the conductive lead 220. As the etching solution flows, a torrent and vortex are formed around the drainage grooves 201, thereby allowing the root of the conductive lead 220 to be fully etched, thus fully eliminating the conductive lead 220.
[0039] In one embodiment, such as Figure 3 As shown, the positions where the conductive lead 220 connects to the thick copper circuit layer 210 are set in an arc shape on both sides.
[0040] In this embodiment, the two sides of the conductive lead 220 are set as concave arcs, so that the width of the conductive lead 220 gradually increases from the position away from the thick copper circuit layer 210 to the position close to the thick copper circuit layer 210. This is beneficial to increase the contact width (contact area) with the thick copper circuit layer 210. On the one hand, it can effectively avoid the tip discharge caused by right angles. On the other hand, it can effectively improve the stability of power supply to the preset area of the thick copper circuit layer 210, thereby avoiding stress concentration and sudden current density changes caused by right angle connection and reducing the risk of edge burning.
[0041] Furthermore, since the root of the conductive lead 220 is set in an arc shape, the corresponding drainage grooves 201 on both sides are also arc-shaped. The arc-shaped drainage grooves 201 make it easier for the flowing etching solution to form a rapid flow and vortex around the drainage grooves 201, thereby ensuring that the root of the conductive lead 220 is fully etched and effectively avoiding etching residue at the root of the conductive lead 220.
[0042] In one embodiment, the step of etching the conductive lead includes: The conductive lead is etched once using an etching solution of a first preset concentration; After the first etching, a second preset concentration of etching solution is used to perform a high-pressure spray on the position where the conductive lead is connected to the thick copper circuit layer for a second etching, wherein the first preset concentration is greater than the second preset concentration.
[0043] In this embodiment, firstly, a high-concentration etching solution is used to etch the conductive lead 220 once, thereby etching away most of the conductive lead 220. Then, a low-concentration etching solution is used, and a high-pressure spray is applied mainly towards the root of the conductive lead 220 for a second etching. In this way, together with the drain trough 201, a turbulent current and vortex can be effectively formed around the drain trough 201, thereby ensuring that the root of the conductive lead 220 is fully etched.
[0044] In one embodiment, such as Figure 3 As shown, at least one of the conductive leads 220 includes a main lead 221 and a plurality of branch leads 222. One end of the main lead 221 is connected to each of the branch leads 222 through a bridging wire 223, and each of the branch leads 222 is connected to the thick copper circuit layer 210.
[0045] In this embodiment, as Figure 3As shown, the conductive lead 220 includes a main lead 221 and multiple branch leads 222. One end of the main lead 221 is connected to each of the branch leads 222 via a bridging wire 223. Each of the branch leads 222 is connected to the thick copper circuit layer 210. The width of the main lead 221 is greater than the width of each branch lead 222. The larger width of the main lead 221 effectively reduces resistance. Through each branch lead 222, the current is guided to each predetermined area of the thick copper circuit layer 210. It is worth mentioning that the length of the main lead 221 is less than the length of each branch lead 222. This allows the current to travel a longer distance on the low-resistance main lead 221, while the shorter length of the branch leads 222 reduces the current transmission distance on the branch leads 222. In this embodiment, by using the main lead 221 and branch lead 222, each branch lead 222 can be made closer to each preset area of the thick copper circuit layer 210. On the one hand, this ensures uniform current distribution, and on the other hand, it can effectively reduce resistance and improve the stability of electroplating.
[0046] Furthermore, by setting the bridging wire 223, the main lead wire can be better connected to each branch lead wire 222. In one embodiment, the extension direction of the bridging wire 223 is perpendicular to the end of the main lead wire near the bridging wire 223 and perpendicular to the end of each branch lead wire 222 away from the root. In this embodiment, the bridging wire 223 is perpendicular to the main lead wire 221 and the branch lead wire 222. On the one hand, its extension direction is perpendicular to the arrangement direction of the branch lead wire 222, which is beneficial to the connection with the branch lead wire 222. On the other hand, it can make the spacing between the branch lead wires 222 larger, avoiding the branch lead wires 222 from being too close together and avoiding uneven distribution of the gold plating layer in the preset area.
[0047] In one embodiment, the ends of the main lead 221 connected to the bridging wire 223 are curved on both sides, and the width of the main lead 221 gradually increases from the position away from the bridging wire 223 to the end closer to the bridging wire 223. The ends of the branch leads 222 connected to the bridging wire 223 are also curved on both sides, and the width of each branch lead 222 gradually increases from the position away from the bridging wire 223 to the end closer to the bridging wire 223. By making the ends of the main lead 221 and each branch lead 222 curved, it is beneficial to smoothly disperse the current during electroplating, reduce the current accumulation at right angles, avoid tip discharge, and make the connection of the main lead 221, the bridging wire 223 and the branch leads 222 more stable.
[0048] In one embodiment, the two sides of the location where the branch lead 222 connects to the thick copper circuit layer 210 are set to be arc-shaped.
[0049] In this embodiment, the two sides of the branch lead 222 are set as concave arcs, so that the width of the branch lead 222 gradually increases from the position away from the thick copper circuit layer 210 to the position close to the thick copper circuit layer 210. This is beneficial to increase the contact width (contact area) with the thick copper circuit layer 210. On the one hand, it can effectively avoid the tip discharge caused by right angles. On the other hand, it can effectively improve the stability of power supply to the preset area of the thick copper circuit layer 210, thereby avoiding stress concentration and current density change caused by right angle connection and reducing the risk of edge burning.
[0050] Furthermore, since the root of the branch lead 222 is set in an arc shape, the corresponding drainage grooves 201 on both sides are also arc-shaped. The arc-shaped drainage grooves 201 make it easier for the flowing etching solution to form a rapid flow and vortex around the drainage grooves 201, thereby ensuring that the root of the branch lead 222 is fully etched and effectively avoiding etching residue at the root of the branch lead 222.
[0051] In one embodiment, each of the conductive leads 220 is configured to be at least one of the following: the spacing between adjacent conductive leads 220 is greater than or equal to 6 mil; the width of the conductive lead 220 is greater than 8 mil; and the distance between each conductive lead 220 and the nearest thick copper circuit layer 210 is greater than or equal to 40 mil.
[0052] In one embodiment, the spacing between adjacent conductive leads 220 is greater than or equal to 6 mil. In this embodiment, the spacing between each branch lead 222 of the same conductive lead 220 is greater than or equal to 6 mil. This allows the current conducted to the thick copper circuit layer 210 to be evenly distributed, resulting in more uniform electroplating. During local gold plating, if adjacent conductive leads 220 are too close together, the edge effect can lead to excessively thick gold plating at the edges of adjacent leads, and even gold overflow may occur. Therefore, in this embodiment, the spacing between adjacent conductive leads 220 is greater than or equal to 6 mil, and the spacing between each branch lead 222 of the same conductive lead 220 is greater than or equal to 6 mil. This provides sufficient flow space for the electroplating solution, ensuring uniform deposition of gold ions, and effectively preventing short circuits between adjacent leads due to poor chemical exchange during subsequent stripping or etching processes.
[0053] In one embodiment, the width of the conductive lead 220 is greater than 8 mil. The instantaneous electroplating current carrying capacity is 100 A / mm². 2This allows the conductive leads 220 to provide sufficient cross-sectional area to carry the required current density. In one embodiment, the width of the main lead 221 is greater than or equal to 40 mil, and the width of each branch lead 222 is 12-14 mil. In this embodiment, the larger width of the main lead 221 results in lower resistance, enabling it to carry a larger current and preventing significant voltage attenuation on the main lead 221, thus ensuring that the gold plating thickness of the distal branch is consistent with that of the proximal branch. The 12-14 mil width of each branch lead 222 provides sufficient cross-sectional area to carry the required current density, resulting in a more uniform current distribution and thus a uniform plating thickness.
[0054] In one embodiment, the distance between each of the conductive leads 220 and the nearest thick copper circuit layer 210 is greater than or equal to 40 mil.
[0055] In this embodiment, the distance between the conductive lead 220 and the nearest thick copper circuit layer 210 refers to the distance perpendicular to the extension direction of the conductive lead 220, that is, on both sides of the extension direction of the conductive lead 220. In this embodiment, the distance between the main lead 221, each branch lead 222 and the nearest thick copper circuit layer 210 is greater than or equal to 40 mil. The large distance between the conductive lead 220 and the thick copper circuit layer 210 on the side provides a larger etching space for subsequent etching processes, avoiding insufficient coverage of the thick copper circuit layer 210 by the coating, and ensuring a large distance between the thick copper circuit layer 210 and the etched conductive lead 220, thereby effectively protecting the edge of the thick copper circuit layer 210 near the conductive lead 220.
[0056] In one embodiment, the step of coating the surface of the circuit board to obtain a first coating, and exposing and developing the first coating to expose a predetermined area of the thick copper circuit layer includes: A laminating machine is used to coat and press the surface of the circuit board, and the coating in the leakage area is re-pressed to obtain a first coating, wherein the first coating is at least partially inserted into the leakage groove. The first coating is exposed and developed to expose a predetermined area of the thick copper circuit layer, and the first coating at least covers the leakage area.
[0057] In this embodiment, when applying the first coating, a laminating machine is used for lamination and lamination. The hot pressing temperature is 105℃-125℃, and the lamination speed is 1.8m-2.5m / min. The coating is in a molten or semi-molten state at high temperature, allowing it to penetrate into the drainage groove. After the first coating is cured, the first coating can be firmly attached to the root of the conductive lead on both sides with the help of the pull of the drainage groove. It can also disperse stress and avoid stress concentration that could cause the first coating to lift off locally at the root of the conductive lead. This effectively prevents gaps between the first coating and the conductive lead, effectively prevents the electroplating solution from penetrating, and thus effectively prevents the formation of an electroplating layer on the root surface of the conductive lead. It is worth mentioning that in traditional thick copper electroplating processes, the large thickness of the copper layer makes it easy for gaps to form at the root of the lead, resulting in plating penetration. This leads to the formation of an electroplated layer at the lead root, consisting of gold and nickel layers that cannot be etched. Consequently, even after the lead is etched, beard-like gold and nickel layers remain, creating a "gold beard" effect. In this embodiment, the pull and stress dispersion effect of the drain groove on the first coating allows the first coating to adhere densely to the root of the conductive lead, effectively preventing plating penetration.
[0058] In order to ensure that the coating can smoothly enter the drainage channel, in one embodiment, a laminating machine is used to apply a coating and a laminating film to the surface of the circuit board using vacuum bonding technology, and the coating in the drainage area is re-pressed to obtain a first coating, wherein the first coating at least partially enters the drainage channel.
[0059] In this embodiment, vacuum bonding is used, allowing the coating to be combed into the drain groove. By applying pressure to the drain area, the coating is firmly embedded in the drain groove, ensuring the first coating is densely attached to the root of the conductive lead. During subsequent exposure and development, the first coating remaining at the root of the conductive lead effectively protects the root, preventing electroplating at the base of the conductive lead.
[0060] In one embodiment, the step of coating the surface of the circuit board to obtain a second coating includes: The surface of the preset area of the thick copper circuit layer is roughened; After roughening the preset area of the thick copper circuit layer, a second coating is applied to the surface of the circuit board to obtain a second coating.
[0061] In this embodiment, sandblasting and micro-etching are used to roughen the surface of the preset area of the thick copper circuit layer, achieving a surface roughness of 1.0 to 1.5 μm. Notably, the micro-uneven structure with a roughness of 1.0 to 1.5 μm provides sufficient mechanical interlocking force to ensure the second coating adheres firmly. Simultaneously, since the height difference between the highest and lowest points of the uneven structure does not exceed the filling capacity of conventional dry films, etching solution infiltration is effectively prevented. It is also worth mentioning that when the surface roughness of the thick copper circuit layer exceeds 2.0 μm, excessively deep trenches can cause the dry film to form plating channels at the steps, significantly increasing the risk of plating infiltration. Therefore, in this embodiment, a surface roughness of 1.0 to 1.5 μm in the preset area allows the second coating to adhere firmly to the preset area of the thick copper circuit layer, preventing etching solution infiltration and effectively protecting the thick copper circuit layer.
[0062] In one embodiment, after the step of roughening the surface of the preset area of the thick copper circuit layer, the method further includes: The surface of the thick copper circuit layer is cleaned.
[0063] In this embodiment, the surface of the circuit board is cleaned before the second coating is applied. This cleaning includes plasma cleaning or chemical cleaning. In this embodiment, the surface of the thick copper circuit layer is treated with plasma or a special cleaning agent before coating to remove oxides and organic matter, thereby improving the adhesion of the thick copper circuit layer. This allows the second coating to adhere firmly to the surface of the thick copper circuit layer, effectively protecting it and preventing etching.
[0064] In one embodiment, the step of etching the conductive leads, and then removing the second coating to obtain a thick copper circuit board includes: The conductive leads are etched, and after etching, the second coating is removed. The surface of the circuit board is coated with solder resist ink to form a solder joint layer. The solder joint layer is then opened to expose the pads, resulting in a thick copper circuit board.
[0065] In this embodiment, after etching the conductive leads and removing the second coating, solder resist ink is applied to the surface of the circuit board to form a solder joint layer on the surface of the circuit board. The solder joint layer is then opened to expose the solder pads, resulting in a thick copper circuit board.
[0066] In this embodiment, the solder resist ink is applied to the effluent area by the process of coating the circuit board surface with solder resist ink, so that the solder resist ink is immersed in the effluent groove and fills the effluent groove. After the solder resist ink is cured, a solder resist layer is formed on the circuit board surface and in the effluent groove, thereby filling the effluent groove.
[0067] In one embodiment, a circuit board is provided, which is manufactured using the circuit board manufacturing method based on thick copper plate internal lead wires as described in any of the above embodiments.
[0068] In this embodiment, since the substrate is provided with drainage grooves on both sides of the root of the conductive lead, the etching solution can flow fully to the root of the conductive lead. As the etching solution flows, a torrent and vortex are formed around the drainage groove, so that the root of the conductive lead is fully etched, thereby completely eliminating the conductive lead.
[0069] The various embodiments of this application have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.
[0070] The technical features of the embodiments described above can be combined arbitrarily. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as the combination of these technical features does not contradict each other, it should be considered within the scope of this specification. It should be noted that the terms "in one embodiment," "for example," and "again," etc., in this application are intended to illustrate the application and not to limit it. The embodiments described above only illustrate several implementations of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be pointed out that for those skilled in the art, several modifications and improvements can be made without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this patent should be determined by the appended claims.
Claims
1. A method for manufacturing a circuit board based on internally drawn leads in a thick copper plate, characterized in that, include: A pre-fabricated circuit board is provided, wherein the circuit board includes a substrate and a thick copper circuit layer disposed on the substrate and a plurality of conductive leads connected to a predetermined area of the thick copper circuit layer, wherein at least one of the conductive leads is connected to the thick copper circuit layer and the two sides of the connection position are drainage areas, and the substrate is provided with drainage grooves in the drainage areas. A first film is obtained by coating the surface of the circuit board. The first film is then exposed and developed to expose a predetermined area of the thick copper circuit layer. Using the conductive leads to conduct electricity, a predetermined area of the thick copper circuit layer is electroplated to form an electroplated layer on the surface of the predetermined area of the thick copper circuit layer. Remove the first coating from the surface of the circuit board; A second film is applied to the surface of the circuit board to obtain a second film. The second film is then exposed and developed to expose the conductive leads. The conductive leads are etched, and after etching, the second coating is removed to obtain a thick copper circuit board.
2. The method according to claim 1, characterized in that, The conductive lead is curved on both sides of the connection point with the thick copper circuit layer.
3. The method according to claim 1, characterized in that, The step of etching the conductive leads includes: The conductive lead is etched once using an etching solution of a first preset concentration; After the first etching, a second preset concentration of etching solution is used to perform a high-pressure spray on the position where the conductive lead is connected to the thick copper circuit layer for a second etching, wherein the first preset concentration is greater than the second preset concentration.
4. The method according to claim 1, characterized in that, At least one of the conductive leads includes a main lead and a plurality of branch leads. One end of the main lead is connected to each of the branch leads via a bridge wire, and each of the branch leads is connected to the thick copper circuit layer.
5. The method according to claim 1, characterized in that, Each of the conductive leads is configured to be at least one of the following: The spacing between adjacent conductive leads is greater than or equal to 6 mil; The width of the conductive lead is greater than 8 mil; The distance between each of the conductive leads and the nearest thick copper circuit layer is greater than or equal to 40 mil.
6. The method according to claim 1, characterized in that, The steps of coating the surface of the circuit board to obtain a first coating, and exposing and developing the first coating to expose a predetermined area of the thick copper circuit layer include: A laminating machine is used to coat and press the surface of the circuit board, and the coating in the leakage area is re-pressed to obtain a first coating, wherein the first coating is at least partially inserted into the leakage groove. The first coating is exposed and developed to expose a predetermined area of the thick copper circuit layer, and the first coating at least covers the leakage area.
7. The method according to claim 1, characterized in that, The step of coating the surface of the circuit board to obtain a second coating includes: The surface of the preset area of the thick copper circuit layer is roughened; After roughening the preset area of the thick copper circuit layer, a second coating is applied to the surface of the circuit board to obtain a second coating.
8. The method according to claim 7, characterized in that, Following the step of roughening the surface of the preset area of the thick copper circuit layer, the method further includes: The surface of the thick copper circuit layer is cleaned.
9. The method according to any one of claims 1-8, characterized in that, The step of etching the conductive leads, and then removing the second coating to obtain a thick copper circuit board includes: The conductive leads are etched, and after etching, the second coating is removed. The surface of the circuit board is coated with solder resist ink to form a solder joint layer. The solder joint layer is then opened to expose the pads, resulting in a thick copper circuit board.
10. A circuit board, characterized in that, The circuit board is manufactured using the circuit board fabrication method based on the internal pull-in wires of a thick copper plate as described in any one of claims 1-9.