Method for manufacturing a circuit board and circuit board

Abstract

This application relates to the field of circuit board manufacturing technology, and more particularly to a method for manufacturing a circuit board and a circuit board itself. The method for manufacturing a circuit board includes: providing a substrate having a circuit layer, the substrate having gold fingers, electroplated leads, and OSP pads, the gold fingers being covered with a nickel-gold layer, the gold fingers including first fingers, the electroplated leads including first leads, the first fingers being connected to the first leads and electrically conductive; attaching an etch protective film to the circuit layer, the etch protective film including a first protective portion, the first protective portion including a first part and a second part, the first part covering the nickel-gold layer on the first fingers, the second part being recessed at the middle of one end away from the first part towards the first part; etching away the first leads not covered by the second part; removing the etch protective film; and performing OSP treatment on the OSP pads. The method for manufacturing a circuit board and the circuit board provided by this application can ensure clean lead etching and guarantee that the suspended nickel-gold length is within acceptable limits.

Description

Technical Field

[0001] This application relates to the field of circuit board manufacturing technology, and in particular to a method for manufacturing a circuit board and a circuit board. Background Technology

[0002] The development of electronic products such as data center network cards is relatively rapid, including smart network cards and high-end expansion cards. These products are mostly designed with gold fingers, and the signal transmission between products is carried out through the gold fingers. The surface treatment is also divided into nickel-palladium-gold and electroplated nickel-gold with OSP (Organic Solderability Preservative) treatment, depending on the design requirements.

[0003] When the surface treatment is electroplating nickel-gold plus OSP treatment, the gold finger leads need to be removed after electroplating nickel-gold. Currently, the leads are generally removed by etching. However, etching the leads not only requires ensuring that the leads are cleanly etched, but also requires that the length of the suspended nickel-gold above the leads is within the acceptable range. Summary of the Invention

[0004] This application provides a method for manufacturing a circuit board and a circuit board that can ensure clean lead etching and guarantee that the length of the suspended nickel-gold is within the acceptable range.

[0005] In a first aspect, embodiments of this application provide a method for manufacturing a circuit board, comprising:

[0006] A substrate is provided, the substrate having a circuit layer, the substrate having gold fingers, electroplated leads and OSP pads, the gold fingers, the electroplated leads and OSP pads are all formed on the circuit layer, the gold fingers are covered with a nickel-gold layer, the gold fingers include a first finger, the electroplated leads include a first lead, the first finger is connected to the first lead and is electrically conductive.

[0007] An etched protective film is attached to the circuit layer. The etched protective film includes a first protective portion, which includes a first part and a second part connected to each other. The first part covers the nickel-gold layer on the first finger, and the second part covers a portion of the first lead. The middle part of the second part away from the first part is recessed towards the first part.

[0008] Etching removes the first lead not covered by the second part;

[0009] Remove the etched protective film;

[0010] The OSP pads are then subjected to OSP processing.

[0011] In some embodiments, the middle portion of the second part at the end furthest from the first part is concave in an arc shape toward the first part.

[0012] In some embodiments, the depth of the recess in the middle of the second part at the end away from the first part toward the first part is 10um-15um.

[0013] In some embodiments, the area of ​​the nickel-gold layer is K, the area of ​​the first lead covered by the second part is L, the ratio of K to L is M, and the dimension of the second part along the distribution direction of the first part and the second part is H, where H is positively correlated with M.

[0014] In some embodiments, the second part has a dimension H along the distribution direction of the first part and the second part; the gold finger also includes a second finger and a third finger, and the electroplated lead also includes a second lead and a third lead, the second finger is connected to the second lead and is electrically conductive, and the third finger is connected to the third lead and is electrically conductive;

[0015] The etched protective film includes a second protective portion and a third protective portion. The second protective portion includes a third portion and a fourth portion connected together. The third portion covers the nickel-gold layer on the second finger, and the fourth portion covers a portion of the second lead. The middle portion of the fourth portion at the end away from the third portion is recessed towards the third portion. The dimension of the fourth portion along the distribution direction of the third portion and the fourth portion is H+H0. The third protective portion includes a fifth portion and a sixth portion connected together. The fifth portion covers the nickel-gold layer on the third finger, and the sixth portion covers a portion of the third lead. The middle portion of the sixth portion at the end away from the fifth portion is recessed towards the fifth portion. The dimension of the sixth portion along the distribution direction of the fifth portion and the sixth portion is H+2*H0.

[0016] When etching away the first lead not covered by the second part, the second lead not covered by the fourth part and the third lead not covered by the sixth part are also etched away.

[0017] In some embodiments, the method of fabricating the circuit board prior to providing the substrate further includes:

[0018] A laminating plate is provided, the laminating plate having a metal layer;

[0019] Finger pads, electroplated leads, and OSP pads are fabricated on the metal layer;

[0020] The area of ​​the metal layer other than the finger pads is covered with an anti-electroplated gold protective film.

[0021] The finger pads are electroplated with nickel-gold using the electroplating leads, so that the nickel-gold layer covers the finger pads, thus obtaining the gold finger;

[0022] Remove the anti-electroplated gold protective film to obtain the substrate.

[0023] In some embodiments, when the finger pads, the electroplated leads, and the OSP pads are fabricated on the metal layer, auxiliary pads are fabricated on the metal layer; the anti-gold plating protective film is provided with auxiliary openings, the auxiliary openings exposing a portion of the auxiliary pads; when the finger pads are electroplated with nickel-gold through the electroplated leads, the auxiliary pads exposed by the auxiliary openings are covered with electroplated nickel-gold PADs; when the etching protective film is attached to the circuit layer, the electroplated nickel-gold PADs are used as positioning references.

[0024] In some embodiments, the shape of the auxiliary pad and the shape of the auxiliary window are both set to be circular.

[0025] In some embodiments, the diameter of the auxiliary pad is 1.5mm-2.0mm, and the diameter of the auxiliary window is 1.00mm-1.25mm.

[0026] Secondly, embodiments of this application provide a circuit board, which is manufactured by the circuit board manufacturing method described in the first aspect.

[0027] The circuit board manufacturing method provided in this application has the following advantages: Since the etched protective film includes a first protective part, which includes a first part and a second part connected to each other, the first part covers the nickel-gold layer on the first finger, and the second part covers part of the first lead, and the middle part of the second part away from the first part is recessed towards the first part, when etching away the first lead not covered by the second part, it can be ensured that the remaining first lead is flush with the end away from the first finger and will not have a pointed tip with a raised middle part. Thus, after OSP treatment of the OSP pad, it can be ensured that the first lead is etched clean and that the suspended nickel-gold length is within the acceptable range.

[0028] The advantages of the circuit board provided in this application compared to the prior art can be seen in the description of the advantages of the manufacturing method of the circuit board provided in this application compared to the prior art, which will not be repeated here. Attached Figure Description

[0029] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0030] Figure 1 This is a schematic diagram of the structure of gold fingers and electroplated leads in the prior art;

[0031] Figure 2 yes Figure 1 The diagram shown illustrates the gold fingers and electroplated leads after OSP treatment.

[0032] Figure 3 yes Figure 1 Another schematic diagram showing the gold fingers and electroplated leads after OSP treatment;

[0033] Figure 4 yes Figure 3 The cross-sectional view corresponding to the gold finger is shown below;

[0034] Figure 5 This is a schematic diagram showing the alignment of the etching protective film and the anti-electroplated gold protective film in the prior art;

[0035] Figure 6 This is a flowchart of a method for manufacturing a circuit board in one embodiment of this application;

[0036] Figure 7 This is a schematic diagram of the structure of the first finger, the first lead, and the first protective part in one embodiment of this application;

[0037] Figure 8 yes Figure 7 A partially enlarged view of the first finger, the first lead wire, and the first protective part shown;

[0038] Figure 9 It is etching removal Figure 7 A schematic diagram of the first lead not covered by the second part;

[0039] Figure 10 yes Figure 9 The diagram shown is a schematic of the first finger after OSP processing.

[0040] Figure 11 yes Figure 10 The cross-sectional view corresponding to the gold finger is shown below;

[0041] Figure 12 This is a schematic diagram of the first finger and the first lead structure in one embodiment of this application;

[0042] Figure 13 This is a schematic diagram of the first finger and the first lead structure in another embodiment of this application;

[0043] Figure 14 This is a schematic diagram of the first finger and the first lead structure in another embodiment of this application;

[0044] Figure 15 This is a schematic diagram of the structure of the first finger, the first lead, the second finger, the second lead, the third finger, and the third lead in one embodiment of this application;

[0045] Figure 16 yes Figure 15 The diagram shown is a schematic of the first finger, first lead, second finger, second lead, third finger, and third lead after OSP processing.

[0046] Figure 17 This is a schematic diagram showing the alignment of the etched protective film and the anti-electroplated gold protective film in one embodiment of this application.

[0047] The markings in the diagram mean:

[0048] 1. Gold fingers; 2. Lead wires; 3. Nickel-gold layer; 4. Curing film; 5. Mechanical holes;

[0049] 100. Substrate;

[0050] 10. First finger; 11. Nickel-gold layer; 20. First lead; 30. Etching protective film; 31. First part; 32. Second part; 40. Curing film; 50. OSP pad; 60. Connection line; 70. Second finger; 71. Second lead; 80. Third finger; 81. Third lead; 90. Auxiliary pad; 91. Electroplated nickel-gold PAD. Detailed Implementation

[0051] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0052] It should be noted that when a component is referred to as being "fixed to" or "set on" another component, it can be directly on or indirectly on that other component. When a component is referred to as being "connected to" another component, it can be directly connected to or indirectly connected to that other component.

[0053] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. 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.

[0054] In this specification, references to "one embodiment," "some embodiments," or simply "embodiment" mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. Furthermore, in one or more embodiments, specific features, structures, or characteristics may be combined in any suitable manner.

[0055] To illustrate the technical solution of this application, the following description is provided in conjunction with specific accompanying drawings and embodiments.

[0056] The development of electronic products such as data center network cards is relatively rapid, such as smart network cards and high-end expansion cards. These products are mostly designed with gold fingers, and the signal transmission between products is carried out through gold fingers. The surface treatment is also divided into nickel-palladium-gold and electroplated nickel-gold with OSP treatment, depending on the design requirements.

[0057] When the surface treatment is electroplating nickel-gold plus OSP treatment, the gold finger leads need to be removed after electroplating nickel-gold. Currently, the leads are generally removed by etching. However, etching the leads not only requires ensuring that the leads are cleanly etched, but also requires that the length of the suspended nickel-gold above the leads is within the acceptable range.

[0058] In related technologies, the etching side etching amount is obtained by slicing through experiments, and the corresponding length is compensated by covering the etched lines with dry film to ensure that the suspended nickel-gold length after etching is within the qualified range. However, this solution is only applicable to circuit board products with electroplated nickel-gold. For circuit boards with electroplated nickel-gold and OSP, when making OSP, due to the inconsistent copper biting amount of the Giovanni effect of different gold finger designs, it is impossible to ensure clean lead etching and suspended nickel-gold length within the qualified range by using the same dry film coverage length. Furthermore, using the slicing method to ensure the suspended nickel-gold length after etching leads requires separate verification for each batch, which is inefficient and may lead to scrap.

[0059] Please refer to Figures 1 to 4When the dry film covers the lead 2, if the area covered by the dry film is designed to be flush, the chemical exchange rate on both sides of the lead 2 is better than the chemical exchange rate on the top of the lead 2 during etching. When etching the lead 2, the chemical will etch from both sides of the lead 2 toward the middle. When the lead 2 is etched off, it will show a raised tip in the middle. As etching continues, the chemical exchange in each area is uniform, and the difference in the amount of etching between the tip and other areas is small. After etching is completed, the middle area of ​​the lead 2 will protrude.

[0060] If the lead 2 of gold finger 1 protrudes, the length of the suspended nickel-gold layer 3 will be acceptable in some areas, but lead 2 will still remain in some areas (e.g. Figure 2 As shown, the length of the nickel-gold suspension in area A1 is acceptable, but there is residual lead length 2 in area B2, or the nickel-gold suspension in some areas is acceptable, but some areas are out of tolerance (e.g., Figure 3 As shown, the length of the nickel-gold suspension at position A2 is not up to standard, but the length of the nickel-gold suspension at position B2 is up to standard. This means that it cannot be guaranteed that the length of the nickel-gold suspension in the raised area and the length of the nickel-gold suspension in the non-raised area of ​​the original etched lead 2 are both up to standard.

[0061] On the other hand, please refer to Figure 5 Generally, an anti-plating gold protective film is first used to cover the area on the circuit board except for the finger pads. Then, nickel-gold plating is performed on the finger pads through lead 2, resulting in a nickel-gold layer 3 covering the finger pads, thus obtaining the gold finger 1. However, when using the anti-plating gold protective film to cover the area on the circuit board except for the finger pads, mechanical holes 5 on the circuit board are often used. There is a deviation between the electroplating nickel-gold position and the theoretical position. When attaching the dry film as an etching protective film on the circuit board, the same mechanical holes 5 as the anti-plating gold protective film are still used for alignment. The alignment deviations are superimposed, making it impossible to guarantee that the length of the dry film covering the lead 2 is within the required range. Figure 5 As shown, when the anti-electroplated nickel-gold protective film is misaligned, the front end of the gold finger 1 is shifted. When the mechanical hole 5 is still used for alignment when making the etched protective film, there is a secondary misalignment. As a result, when the etched protective film should theoretically cover the lead 2 for a length of L1, it actually covers the lead 2 for a length of only L2, where L2 < L1.

[0062] In view of this, this application provides a method for manufacturing a circuit board and a circuit board. Since the etched protective film includes a first protective part, the first protective part includes a first part and a second part connected to each other. The first part covers the nickel-gold layer on the first finger, and the second part covers part of the first lead. The middle part of the second part away from the first part is recessed towards the first part. Therefore, when etching away the first lead not covered by the second part, it can be ensured that the remaining first lead is flush with the end away from the first finger and does not have a pointed tip with a raised middle part. Thus, after OSP treatment of the OSP pad, it can be ensured that the first lead is etched clean and that the suspended nickel-gold length is within the acceptable range.

[0063] Please refer to Figures 6 to 11 In a first aspect, embodiments of this application provide a method for manufacturing a circuit board, comprising:

[0064] S100: A substrate 100 is provided. The substrate 100 has a circuit layer. The substrate 100 is provided with gold fingers, electroplated leads and OSP pads 50. The gold fingers, electroplated leads and OSP pads 50 are all formed on the circuit layer. A nickel-gold layer 11 is covered on the gold fingers. The gold fingers include first fingers 10. The electroplated leads include first leads 20. The first fingers 10 and the first leads 20 are connected and electrically conductive.

[0065] Specifically, the substrate 100 may include a cured sheet 40 and a circuit layer, which may be a copper layer or the like. The nickel-gold layer 11 may include a gold layer and a nickel layer.

[0066] S200: An etched protective film 30 is attached to the circuit layer. The etched protective film 30 includes a first protective part. The first protective part includes a first part 31 and a second part 32 connected to each other. The first part 31 covers the nickel-gold layer 11 on the first finger 10. The second part 32 covers part of the first lead 20. The middle part of the second part 32 away from the first part 31 is recessed towards the first part 31.

[0067] Specifically, the etched protective film 30 can be a dry film or the like. An LDI (Laser Direct Imaging) exposure machine can be used to cover the nickel-gold layer 11 on the first finger 10 with the first part 31, and the second part 32 covers part of the first lead 20, OSP pads 50 and other lines with the etched protective film 30.

[0068] S300: Etching removes the first lead 20 that is not covered by the second part 32.

[0069] Specifically, the windowed portion of the first lead 20 not covered by the second part 32 is removed by chemical etching. Since the middle part of the second part 32 at the end away from the first part 31 is recessed towards the first part 31, the uneven etching at different positions at the end of the second part 32 away from the first part 31 can be avoided, which would cause the end of the second part 32 to protrude.

[0070] S400: Remove etched protective film 30.

[0071] Specifically, the etched protective film 30 can be removed by stripping. After removing the etched protective film 30, a larger substrate 100 can be machined to the required size using a mechanical milling method, and the electrical performance of the finished board can be tested.

[0072] S500: Perform OSP processing on OSP pad 50.

[0073] Specifically, the substrate 100 can be impregnated with OSP solution to generate an organic film on the OSP pads 50. Due to the Giavani effect, the first lead 20 covered by the second part 32 is etched away, ensuring that the first lead 20 is cleanly etched and that the suspended nickel-gold length is within acceptable limits.

[0074] As can be seen from the above, the circuit board manufacturing method provided in this application embodiment includes a first protective part etched with a protective film 30. The first protective part includes a first part 31 and a second part 32 connected to each other. The first part 31 covers the nickel-gold layer 11 on the first finger 10, and the second part 32 covers part of the first lead 20. The middle part of the second part 32 away from the first part 31 is recessed towards the first part 31. Therefore, when etching away the first lead 20 not covered by the second part 32, it can be ensured that the remaining first lead 20 is flush with the end away from the first finger 10 and does not have a pointed tip with a raised middle. Thus, after OSP treatment of the OSP pad 50, it can be ensured that the first lead 20 is etched clean and that the suspended nickel-gold length is within the acceptable range.

[0075] After OSP processing of OSP pad 50, subsequent processes can be completed in sequence, such as FQC (Final Quality Control), FQA (Factory Quality Assurance), and packaging.

[0076] Optionally, the middle part of the second part 32 at the end away from the first part 31 is concave in an arc shape towards the first part 31.

[0077] This configuration ensures that when etching away the first lead 20 not covered by the second part 32, the remaining first lead 20 is flush with the end away from the first finger 10 and does not present a pointed shape with a raised center.

[0078] Optionally, the depth D1 of the recess in the middle of the end of the second part 32 away from the first part 31 toward the first part 31 is 10um-15um, such as 10um, 11um, 12um, 13um, 14um or 15um.

[0079] This configuration ensures that when etching away the first lead 20 not covered by the second part 32, the remaining first lead 20 is flush with the end away from the first finger 10 and does not present a pointed shape with a raised center.

[0080] It should be noted that the depth D1 of the recess in the middle of the end of the second part 32 away from the first part 31 towards the first part 31 is determined according to the width and etching amount of the first lead 20. A circle is drawn through the two endpoints of the second part 32 that contact the first lead 20 and the point at the bottom of the depth, retaining the arc at the bottom, to achieve the concave design requirement of the middle of the end of the second part 32 away from the first part 31.

[0081] Please refer to Figures 12 to 14 In some embodiments, the area of ​​the nickel-gold layer 11 is K, the area of ​​the first lead 20 covered by the second part 32 is L, the ratio of K to L is M, and the size of the second part 32 along the distribution direction of the first part 31 and the second part 32 is H, where H is positively correlated with M.

[0082] By adopting the above scheme, the size of the second part 32 along the distribution direction of the first part 31 and the second part 32 can be dynamically adjusted according to the ratio of the area of ​​the nickel-gold layer 11 to the area of ​​the electroplated leads covered by the second part 32.

[0083] Wherein, H = the side etching amount of the first lead 20 H1 + the OSP galvanic etching amount H2, where H1 is a constant value, and the side etching amount can be ensured to be H1 by adjusting the etching parameters, that is, to ensure that the residual amount after the first lead 20 is etched is the OSP galvanic etching amount H2.

[0084] The Giovanni etching amount H2 is related to the gold-copper ratio (the area of ​​the nickel-gold layer 11 and the area of ​​the electroplated lead covered by the second part 32). Under the same OSP parameters, the larger the gold-copper ratio, the greater the etching amount of copper. Theoretically, under the premise of the same gold-copper ratio, the etching amount of the first lead 20 after OSP treatment is the same. In this embodiment, for ease of calculation, under the premise of fixed gold finger lead width, after OSP treatment with a gold-copper ratio of 200:1, the loss area S1 of the first lead 20 caused by the Giovanni effect is called the basic etching amount. The lead length corresponding to the basic etching amount is H3 = 10um. When different gold finger sizes, or when the gold finger is connected to the OSP pad 50 (at this time, the copper area is the residual area of ​​the gold finger lead + the area of ​​the OSP pad 50), the copper surface area will also change. The areas of different gold fingers are compared with the basic etching amount area S1. For example, when the gold-copper ratio is ≤200:1, the Giaviani etching amount H2 = H3; when the gold-copper ratio is >200:1 and ≤200:1, the Giaviani etching amount H2 = H3 + 5 μm; when the gold-copper ratio is >300:1 and ≤400:1, the Giaviani etching amount H2 = H3 + 10 μm; and when the gold-copper ratio is >400:1 and ≤500:1, the Giaviani etching amount H2 = H3 + 15 μm.

[0085] Based on actual case analysis, for every 100:1 increase in the gold-copper ratio, the corresponding etching amount will increase by 5µm. The final javanni etching amount H2 was determined, and combined with the etching amount H1 of the first lead 20, H was determined.

[0086] like Figure 12 As shown, in one embodiment, the gold finger is connected to the OSP pad 50 via a connection line 60. The area of ​​the copper is the sum of the area of ​​the first lead 20 covered by the second part 32 and the area of ​​the OSP pad 50. The corresponding gold-copper ratio is 160:1, and the Giovanni etching amount is H2 = 10um.

[0087] like Figure 13 As shown, in one embodiment, the gold finger is not connected to the OSP pad 50, and the gold finger size is small with a gold-copper ratio of 230:1. In this case, H2 = H3 + 5um, which is 15um.

[0088] like Figure 14 As shown, in one embodiment, the gold finger is not connected to the OSP pad 50, and the gold finger size is relatively large with a gold-copper ratio of 450:1. In this case, H2 = H3 + 15um, which is 25um.

[0089] Please refer to Figure 15 and Figure 16 In some embodiments, the second part 32 has a dimension of H along the distribution direction of the first part 31 and the second part 32; the gold fingers also include a second finger 70 and a third finger 80, and the electroplated leads also include a second lead 71 and a third lead 81, the second finger 70 is connected to the second lead 71 and is electrically conductive, and the third finger 80 is connected to the third lead 81 and is electrically conductive.

[0090] The etched protective film 30 includes a second protective portion and a third protective portion. The second protective portion includes a third portion and a fourth portion connected together. The third portion covers the nickel-gold layer 11 on the second finger 70, and the fourth portion covers a portion of the second lead 71. The middle portion of the fourth portion away from the third portion is recessed towards the third portion. The dimension of the fourth portion along the distribution direction of the third portion and the fourth portion is H+H0. The third protective portion includes a fifth portion and a sixth portion connected together. The fifth portion covers the nickel-gold layer 11 on the third finger 80, and the sixth portion covers a portion of the third lead 81. The middle portion of the sixth portion away from the fifth portion is recessed towards the fifth portion. The dimension of the sixth portion along the distribution direction of the fifth portion and the sixth portion is H+2*H0.

[0091] When etching away the first lead 20 not covered by the second part 32, the second lead 71 not covered by the fourth part and the third lead 81 not covered by the sixth part are also etched away.

[0092] By adopting the above scheme, after OSP processing of OSP pad 50, the residual condition of the second lead 71 corresponding to the second finger 70 and the residual condition of the third lead 81 corresponding to the third finger 80 can be observed to determine the suspended nickel-gold condition of the first finger 10. Based on this result, the OSP parameters can be adjusted to ensure that the suspended nickel-gold length of different gold fingers is within the specification range and there is no residue of the first lead 20, without the need for destructive slicing.

[0093] It should be noted that both the second finger 70 and the third finger 80 can be located on the broken edge of the substrate 100.

[0094] For example, when H0 = 5µm, if the first lead 20 remains after OSP treatment of OSP pad 50, it indicates that the OSP treatment has not achieved the set Gavani effect effect, and the OSP parameters should be adjusted to increase the Gavani effect. If the first lead 20 remains after OSP treatment of OSP pad 50, and the second lead 71 and / or the third lead 81 have no lead residue, it proves that the Gavani effect is serious and there is a risk of exceeding the tolerance for nickel-gold suspension length. The OSP parameters should be adjusted appropriately to reduce the Gavani effect until the second lead 71 has 5µm of residue and the third lead 81 has 10µm of residue. Then it proves that the OSP parameters are reasonable and mass production is possible. In this case, there is no need to perform slicing to confirm the nickel-gold suspension effect.

[0095] It should be noted that adjusting the OSP parameters can adjust the concentration of the OSP solution or the OSP treatment time.

[0096] Please refer to Figure 17 In some embodiments, the method of fabricating the circuit board before providing the substrate 100 further includes:

[0097] First, a lamination plate is provided, which has a metal layer.

[0098] Specifically, the laminated board can complete the previous processes according to the normal procedure, such as material cutting, inner layer circuitry, AOI (Automated Optical Inspection), lamination, target drilling, edge milling, drilling and filling, etc.

[0099] Next, finger pads, electroplated leads, and OSP pads 50 are fabricated on the metal layer.

[0100] Next, apply an anti-plating gold protective film to cover the area of ​​the metal layer except for the finger pads. An LDI exposure machine can be used to expose the finger pads.

[0101] Next, the finger pads are electroplated with nickel-gold through electroplating leads, so that a nickel-gold layer 11 is covered on the finger pads, thus obtaining a gold finger.

[0102] Specifically, a nickel and gold layer of the target thickness is plated onto the finger pads exposed by the openings in the anti-plating gold protective film through a chemical reaction.

[0103] Then, the anti-plating gold protective film is removed to obtain substrate 100.

[0104] By adopting the above scheme, the substrate 100 can be manufactured relatively easily.

[0105] It should be noted that the anti-plating gold protective film can be a dry film, etc. When fabricating finger pads, electroplated leads, and OSP pads 50 on the metal layer, other circuitry can be fabricated simultaneously. After removing the anti-plating gold protective film to obtain the substrate 100, ink is screen-printed on the substrate 100, pre-baked, exposed, and developed. Windows are created in the areas where insertion / removal and soldering are required (where OSP pads 50 are located), and the remaining areas are protected with ink. Note that the electroplated leads used for nickel-gold plating, as well as the auxiliary pads 90, need to be windowed.

[0106] Specifically, when the finger pads, electroplated leads, and OSP pads 50 are fabricated on the metal layer, auxiliary pads 90 are fabricated on the metal layer; the anti-electroplated gold protective film is provided with auxiliary openings, which expose part of the auxiliary pads 90; when the finger pads are electroplated with nickel-gold through the electroplated leads, the auxiliary pads 90 exposed by the auxiliary openings are covered with electroplated nickel-gold PAD91; when the etching protective film 30 is attached to the circuit layer, the electroplated nickel-gold PAD91 is used as the positioning reference.

[0107] By adopting the above scheme, the attachment accuracy of the etching protective film 30 can be improved, the alignment deviation between the nickel-gold layer 11 and the etching protective film 30 caused by the use of traditional mechanical hole alignment can be reduced, the deviation between the actual length of the etching protective film 30 covering the first lead 20 and the theoretical length of the coverage can be reduced, and the length L3 of the etching protective film 30 covering the first lead 20 will be close to the theoretical length L1 of the lead that the etching protective film 30 should cover.

[0108] Optionally, the shape of the auxiliary pad 90 and the shape of the auxiliary window are both set to circular.

[0109] This setup makes it easier to create auxiliary pads 90 and auxiliary windows.

[0110] Optionally, the diameter of the auxiliary pad 90 is 1.5mm-2.0mm, such as 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm or 2.0mm, and the diameter of the auxiliary window is 1.00mm-1.25mm, such as 1.00mm, 1.05mm, 1.10mm, 1.15mm, 1.20mm or 1.25mm.

[0111] This setup facilitates the fabrication of auxiliary pads 90 and auxiliary windows, and also makes it easy to cover the auxiliary pads 90 exposed by the auxiliary windows with electroplated nickel-gold PAD91.

[0112] It should be noted that the auxiliary pad 90 can be a copper pad located in the copper grid area (connected to the electroplating clamping points) on the edge of the lamination board. The auxiliary opening can be located at the center of the auxiliary pad 90.

[0113] Secondly, embodiments of this application provide a circuit board, which is manufactured by the circuit board manufacturing method of the first aspect.

[0114] The circuit board provided in this application embodiment includes a first protective part 30, which includes a first part 31 and a second part 32 connected to each other. The first part 31 covers the nickel-gold layer 11 on the first finger 10, and the second part 32 covers part of the first lead 20. The middle part of the second part 32 away from the first part 31 is recessed towards the first part 31. Therefore, when etching away the first lead 20 not covered by the second part 32, it can be ensured that the remaining first lead 20 away from the first finger 10 is flush and does not have a pointed tip with a raised middle. Thus, after OSP treatment of the OSP pad 50, it can be ensured that the lead is cleanly etched and that the suspended nickel-gold length is within the acceptable range.

[0115] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A method for manufacturing a circuit board, characterized in that, include: A substrate is provided, the substrate having a circuit layer, the substrate having gold fingers, electroplated leads and OSP pads, the gold fingers, the electroplated leads and OSP pads being formed on the circuit layer, the gold fingers being covered with a nickel-gold layer, the gold fingers including a first finger, the electroplated leads including a first lead, the first finger being connected to the first lead and electrically conductive, the gold fingers also including a second finger and a third finger, the electroplated leads also including a second lead and a third lead, the second finger being connected to the second lead and electrically conductive, the third finger being connected to the third lead and electrically conductive; An etched protective film is attached to the circuit layer. The etched protective film includes a first protective portion, which comprises a first part and a second part connected together. The first part covers the nickel-gold layer on the first finger, and the second part covers a portion of the first lead. The middle portion of the second part, away from the first part, is recessed towards the first part. The second part has a dimension H along the distribution direction of the first part and the second part. The etched protective film also includes a second protective portion and a third protective portion. The second protective portion comprises a third part and a fourth part connected together. The third part covers the nickel layer on the second finger. The third protective portion includes a gold layer, wherein the fourth part covers a portion of the second lead, and the middle portion of the fourth part at the end away from the third part is recessed towards the third part, and the dimension of the fourth part along the distribution direction of the third part and the fourth part is H+H0; the third protective portion includes a fifth part and a sixth part connected to each other, the fifth part covers the nickel-gold layer on the third finger, the sixth part covers a portion of the third lead, and the middle portion of the sixth part at the end away from the fifth part is recessed towards the fifth part, and the dimension of the sixth part along the distribution direction of the fifth part and the sixth part is H+2*H0; The first lead not covered by the second part is etched away, and the second lead not covered by the fourth part and the third lead not covered by the sixth part are etched away. Remove the etched protective film; The OSP pads are then subjected to OSP processing.

2. The method for manufacturing a circuit board according to claim 1, characterized in that, The middle part of the second part, which is away from the first part, is concave in an arc shape towards the first part.

3. The method for manufacturing a circuit board according to claim 2, characterized in that, The depth of the second part recessed from the middle of the end away from the first part toward the first part is 10um-15um.

4. The method for manufacturing a circuit board according to claim 1, characterized in that, The area of ​​the nickel-gold layer is K, the area of ​​the first lead covered by the second part is L, the ratio of K to L is M, the dimension of the second part along the distribution direction of the first part and the second part is H, and H is positively correlated with M.

5. The method for manufacturing a circuit board according to any one of claims 1 to 4, characterized in that, Before providing the substrate, the method for manufacturing the circuit board further includes: A laminating plate is provided, the laminating plate having a metal layer; Finger pads, electroplated leads, and OSP pads are fabricated on the metal layer; The area of ​​the metal layer other than the finger pads is covered with an anti-electroplated gold protective film. The finger pads are electroplated with nickel-gold using the electroplating leads, so that the nickel-gold layer covers the finger pads, thus obtaining the gold finger; Remove the anti-electroplated gold protective film to obtain the substrate.

6. The method for manufacturing a circuit board according to claim 5, characterized in that, When the finger pads, the electroplated leads, and the OSP pads are fabricated on the metal layer, auxiliary pads are fabricated on the metal layer; the anti-electroplated gold protective film is provided with auxiliary openings, and the auxiliary openings expose a portion of the auxiliary pads; when the finger pads are electroplated with nickel-gold through the electroplated leads, the auxiliary pads exposed by the auxiliary openings are covered with electroplated nickel-gold PADs; when the etching protective film is attached to the circuit layer, the electroplated nickel-gold PADs are used as positioning references.

7. The method for manufacturing a circuit board according to claim 6, characterized in that, Both the auxiliary pad and the auxiliary window are circular in shape.

8. The method for manufacturing a circuit board according to claim 7, characterized in that, The diameter of the auxiliary pad is 1.5mm-2.0mm, and the diameter of the auxiliary window is 1.00mm-1.25mm.

9. A circuit board, characterized in that, The circuit board is manufactured by the circuit board manufacturing method as described in any one of claims 1 to 8.

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