PCB surface treatment methods and PCB

Abstract

This application relates to the field of circuit board manufacturing technology, and discloses a PCB surface treatment method and a PCB. The PCB surface treatment method includes: providing a substrate with a printing surface, the printing surface including a first region and a second region, a first pad being disposed in the first region, and a second pad being disposed in the second region; printing protective ink in the first region using a first printing screen, the first printing screen being provided with window channels, the window channels including a first channel and a second channel, the first channel having a first cross-section parallel to the printing surface as a first cross-section, the ratio of the perimeter of the first cross-section to the area of ​​the first cross-section being D1, the second channel having a second cross-section parallel to the printing surface as a second cross-section, the ratio of the perimeter of the second cross-section to the area of ​​the second cross-section being D2, D2 being greater than D1. The PCB surface treatment method of this application can reduce the risk of protective ink penetrating into the second region where the second pad is located.

Description

Technical Field

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

[0002] With the development of surface mount technology and chip packaging technology, the functional requirements of PCB surface coating are increasing. The production process not only needs to make more precise circuits and pads with higher flatness, but may also need to provide hybrid assembly technology that takes into account both solderability and bonding. Therefore, the pads on some PCBs (such as selective gold plating) need to be designed with two surface treatments at the same time, such as selective gold plating process, which uses gold plating surface treatment in combination with other surface treatment processes.

[0003] Currently, a common method for manufacturing surface treatment boards is to use thermosetting protective ink to cover the pads in the area to be protected, exposing the pads in other areas to be surface treated. However, when the area to be protected is too close to the pads to be surface treated, the protective ink in the area to be protected may penetrate into the area where the pads to be surface treated are located, causing quality defects. Summary of the Invention

[0004] This application provides a PCB surface treatment method and a PCB, which can reduce the risk that the protective ink in the area to be protected will penetrate into the area where the pad to be surface treated is located when the area to be protected is too close to the pad to be surface treated.

[0005] In a first aspect, embodiments of this application provide a PCB surface treatment method, including:

[0006] A substrate is provided, the substrate having a printing surface, the printing surface including a first region and a second region spaced apart, a first pad being disposed in the first region and a second pad being disposed in the second region;

[0007] Protective ink is printed in the first area using a first printing screen. The first printing screen is provided with a windowed channel, which includes a first channel and a second channel connected to the first channel. The first channel corresponds to the first area, and the second channel is located on the side of the first channel closer to the second area. The first channel has a first cross-section parallel to the printing surface, and the ratio of the perimeter of the first cross-section to the area of ​​the first cross-section is D1. The second channel has a second cross-section parallel to the printing surface, and the ratio of the perimeter of the second cross-section to the area of ​​the second cross-section is D2, where D2 > D1.

[0008] In some embodiments, the first cross section is rectangular in shape, and the second cross section is rhomboid or triangular in shape.

[0009] In some embodiments, the window opening channel includes a third channel connected to the first channel, the third channel and the second channel are located on opposite sides of the first channel, the third channel has a third cross section parallel to the printing surface, and the ratio of the perimeter of the third cross section to the area of ​​the third cross section is D3, where D3 < D1.

[0010] In some embodiments, the third cross section is circular or semi-circular in shape.

[0011] In some embodiments, before printing protective ink on the first region using a first printing screen, a flow-blocking portion located between the first region and the second region is printed on the printing surface.

[0012] In some embodiments, the flow-blocking portion is configured as a groove, and the flow-blocking portion located between the first region and the second region is printed on the printing surface, including:

[0013] A first solder resist ink is printed on the printing surface using a second printing screen, the second printing screen having a dotted strip located between the first region and the second region;

[0014] The substrate is pre-baked;

[0015] A second solder resist ink is printed on the first solder resist ink using a third printing screen, such that the groove is formed between the first region and the second region;

[0016] Exposure and development expose the first pad and the second pad.

[0017] In some embodiments, the flow-blocking portion is configured as a protrusion, and the flow-blocking portion located between the first region and the second region is printed on the printing surface, including:

[0018] A fourth printing screen is used to print a dam located between the first and second regions on the printing surface;

[0019] The substrate is pre-baked;

[0020] A fifth printing screen is used to print a third solder resist ink over the printing surface, the third solder resist ink covering the dam, so that the protrusion is formed between the first region and the second region;

[0021] Exposure and development expose the first pad and the second pad.

[0022] In some embodiments, the first pad is subjected to a first surface treatment before printing protective ink on the first area using a first printing screen; and the second pad is subjected to a second surface treatment after printing protective ink on the first area using the first printing screen.

[0023] In some embodiments, after printing protective ink on the first area using a first printing screen, the PCB surface treatment method further includes:

[0024] Perform a third surface treatment on the second pad;

[0025] Remove the protective ink from the first area;

[0026] The first pad is subjected to a fourth surface treatment.

[0027] Secondly, embodiments of this application provide a PCB manufactured according to the PCB surface treatment method described in the first aspect.

[0028] The PCB surface treatment method provided in this application has the following advantages: Since the first printing screen is provided with a window channel, which includes a first channel and a second channel connected to the first channel, the first channel corresponds to the first region, and the second channel is located on the side of the first channel close to the second region. Therefore, when the first printing screen is used to print protective ink on the first region of the printing surface of the substrate, the protective ink will flow onto the printing surface through the window channel. Also, since the first channel has a first cross section parallel to the printing surface, and the ratio of the perimeter of the first cross section to the area of ​​the first cross section is D1, and the second channel has a second cross section parallel to the printing surface, and the ratio of the perimeter of the second cross section to the area of ​​the second cross section is D2, D2 > D1, the flow rate of the protective ink flowing onto the printing surface through the first channel will be greater than the flow rate of the protective ink flowing onto the printing surface through the second channel. Therefore, in the same amount of time, more protective ink flows onto the first region through the first channel, and less protective ink flows onto the area around the first region through the second channel, thereby reducing the risk of protective ink penetrating into the second region where the second pad is located.

[0029] The advantages of the PCB provided in this application compared to the prior art are the same as the advantages of the PCB surface treatment method provided in this application compared to the prior art, and will not be repeated here. Attached Figure Description

[0030] 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.

[0031] Figure 1 This is a flowchart of a PCB surface treatment method in one embodiment of this application;

[0032] Figure 2 This is a schematic diagram of the substrate structure in one embodiment of this application;

[0033] Figure 3 It is used in Figure 2 A schematic diagram of the structure of the first printing screen for printing protective ink on the first region of the substrate shown.

[0034] Figure 4 Is Figure 2 A schematic diagram of the substrate structure after the flow-blocking section has been printed on the substrate;

[0035] Figure 5 (a) in Figure 2 A cross-sectional view of a substrate on which the first solder resist ink is printed.

[0036] Figure 5 (b) in the middle is Figure 5 The cross-sectional view of the substrate on which the second solder resist ink is printed, shown in (a).

[0037] The markings in the diagram mean:

[0038] 10. Substrate; 11. Printed surface; 111. First region; 112. Second region; 20. First pad; 30. Second pad; 40. First printing screen; 41. Window channel; 411. First channel; 412. Second channel; 413. Third channel; 50. First solder resist ink; 60. Second solder resist ink; 70. Flow barrier; 71. Groove; 80. First surface layer. Detailed Implementation

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] To illustrate the technical solution of this application, the following description is provided in conjunction with specific accompanying drawings and embodiments.

[0044] Please refer to Figure 1 , Figure 2 and Figure 3 In a first aspect, embodiments of this application provide a PCB surface treatment method, including:

[0045] S100: A substrate 10 is provided. The substrate 10 has a printing surface 11. The printing surface 11 includes a first region 111 and a second region 112 that are spaced apart. A first pad 20 is provided in the first region 111 and a second pad 30 is provided in the second region 112.

[0046] Specifically, the substrate 10 can be a 6-layer board and complete the preceding processes according to the normal process, namely, material cutting, inner layer circuitry, AOI (Automated Optical Inspection), lamination, target drilling, edge milling, drilling, outer layer pattern transfer, outer layer etching, and AOI.

[0047] It is understandable that the projection of the first pad 20 on the printed surface 11 can coincide with the first region 111, and the projection of the second pad 30 on the printed surface 11 can coincide with the second region 112.

[0048] It is understandable that the first pad 20 and the second pad 30 require different surface treatment processes. Therefore, one of the first pad 20 and the second pad 30 needs to be covered with protective ink, and then the other needs to be surface treated.

[0049] S200: Using a first printing screen 40, protective ink is printed in the first area 111. The first printing screen 40 is provided with a window channel 41, which includes a first channel 411 and a second channel 412 connected to the first channel 411. The first channel 411 corresponds to the first area 111, and the second channel 412 is located on the side of the first channel 411 close to the second area 112. The first channel 411 has a first cross section parallel to the printing surface 11, and the ratio of the perimeter of the first cross section to the area of ​​the first cross section is D1. The second channel 412 has a second cross section parallel to the printing surface 11, and the ratio of the perimeter of the second cross section to the area of ​​the second cross section is D2, where D2 is greater than D1.

[0050] Specifically, the protective ink flows to the printing surface 11 through the windowed channel 41. Multiple second channels 412 can be spaced out, such as... Figure 4 Multiple sections are arranged along the vertical direction. The shape of the first section can be rectangular, and the shape of the second section can be rhomboid or triangular. The protective ink can be a selective ink.

[0051] Understandably, to ensure that protective ink is printed on the first pad 20 and to eliminate alignment errors, when printing protective ink on the first region 111 using the first printing screen 40, the first region 111 is located inside the projection of the window channel 41 onto the printing surface 11, meaning that the area of ​​the window channel 41 along its cross-section parallel to the printing surface 11 is larger than the area of ​​the first region 111. The first channel 411 can be composed of multiple screen openings, and the second channel 412 can also be composed of multiple screen openings, or the second channel 412 can be a single screen opening.

[0052] Understandably, since D2 is greater than D1, the flow rate of the protective ink flowing into the printing surface 11 through the first channel 411 will be greater than the flow rate of the protective ink flowing into the printing surface 11 through the second channel 412. Therefore, in the same amount of time, more protective ink flows into the first region 111 through the first channel 411, and less protective ink flows into the area around the first region 111 through the second channel 412. That is, when the required amount of protective ink is printed on the first pad 20, the amount of protective ink flowing into the area around the first region 111 through the second channel 412 will be less than the amount of protective ink flowing into the first region 111 through the first channel 411. This can reduce the risk of protective ink penetrating into the second region 112 where the second pad 30 is located.

[0053] The PCB surface treatment method provided in this application embodiment has a windowed channel 41 on the first printing screen 40. The windowed channel 41 includes a first channel 411 and a second channel 412 connected to the first channel 411. The first channel 411 corresponds to the first region 111, and the second channel 412 is located on the side of the first channel 411 closer to the second region 112. Therefore, when the first printing screen 40 prints protective ink on the first region 111 of the printing surface 11 of the substrate 10, the protective ink will flow onto the printing surface 11 through the windowed channel 41. Furthermore, since the first channel 411 has a first cross-section parallel to the printing surface 11, the first cross-section... The ratio of the perimeter of the surface to the area of ​​the first cross section is D1. The second channel 412 has a cross section parallel to the printing surface 11, which is called the second cross section. The ratio of the perimeter of the second cross section to the area of ​​the second cross section is D2, where D2 > D1. Therefore, the flow rate of the protective ink flowing into the printing surface 11 through the first channel 411 is greater than that of the protective ink flowing into the printing surface 11 through the second channel 412. As a result, more protective ink flows into the first region 111 through the first channel 411 in the same amount of time, while less protective ink flows into the area around the first region 111 through the second channel 412. This reduces the risk of the protective ink penetrating into the second region 112 where the second pad 30 is located.

[0054] The PCB surface treatment method provided in this application embodiment has a simple process and can solve the problems of high PCB cost and long process.

[0055] Please refer to Figure 2 and Figure 3 In some embodiments, the window channel 41 includes a third channel 413 connected to the first channel 411. The third channel 413 and the second channel 412 are located on both sides of the first channel 411, respectively. The third channel 413 has a third cross section parallel to the printing surface 11. The ratio of the perimeter of the third cross section to the area of ​​the third cross section is D3, where D3 < D1.

[0056] By adopting the above scheme, the flow rate of the protective ink flowing into the printing surface 11 through the third channel 413 can be greater than the flow rate of the protective ink flowing into the printing surface 11 through the first channel 411. This allows the protective ink flowing into the printing surface 11 through the third channel 413 to flow onto the printing surface 11 more quickly and without penetrating into the second region 112 where the second pad 30 is located.

[0057] It is understandable that the third channel 413 can be composed of multiple screen holes, or the third channel 413 can be a single screen hole.

[0058] Optionally, the third channel 413 can be configured in multiple groups, for example, in Figure 4 In the middle, a set of third channels 413 are provided above, below and to the left of the first channel 411, and multiple third channels 413 form a group, and the second channel 412 is located to the right of the first channel 411.

[0059] Optionally, the shape of the third section is circular or semi-circular.

[0060] Please refer to Figures 2 to 4 In some embodiments, before using the first printing screen 40 to print protective ink in the first region 111, a flow-blocking portion 70 located between the first region 111 and the second region 112 is printed on the printing surface 11.

[0061] By adopting the above solution, the flow-blocking part 70 can be used to block the protective ink flowing from the first region 111 to the second region 112, thereby reducing the risk of the protective ink penetrating into the second region 112 where the second pad 30 is located.

[0062] Please refer to this as well. Figure 5 (a) and Figure 5 In embodiment (b), the flow-blocking portion 70 is configured as a groove 71. The flow-blocking portion 70 located between the first region 111 and the second region 112 is printed on the printing surface 11, including:

[0063] First, a first solder resist ink 50 is printed on the printing surface 11 using a second printing screen. The second printing screen is provided with a dot strip located between the first region 111 and the second region 112.

[0064] Next, the substrate 10 is pre-baked, for example, by pre-baking at 125℃ for 45 minutes.

[0065] Next, a third printing screen is used to print a second solder resist ink 60 on the first solder resist ink 50, so that a groove 71 is formed between the first region 111 and the second region 112.

[0066] Finally, exposure and development are performed to expose the first pad 20 and the second pad 30.

[0067] By adopting the above solution, the tendency of protective ink to flow into the second region 112 can be slowed down, thereby reducing the risk of protective ink penetrating into the second region 112 where the second pad 30 is located.

[0068] In another embodiment, the flow-blocking portion 70 is configured as a protrusion, and the flow-blocking portion 70 located between the first region 111 and the second region 112 is printed on the printing surface 11, including:

[0069] First, the dam located between the first region 111 and the second region 112 is printed on the printing surface 11 using the fourth printing screen.

[0070] Next, the substrate 10 is pre-baked.

[0071] Next, a third solder resist ink is printed on the printing surface 11 using a fifth printing screen. The third solder resist ink covers the dam, forming a protrusion between the first region 111 and the second region 112.

[0072] Finally, exposure and development are performed to expose the first pad 20 and the second pad 30.

[0073] By adopting the above solution, the tendency of protective ink to flow into the second region 112 can be slowed down, thereby reducing the risk of protective ink penetrating into the second region 112 where the second pad 30 is located.

[0074] Please refer to Figure 5 In embodiment (b), before printing protective ink in the first area 111 using the first printing screen 40, the first pad 20 undergoes a first surface treatment, such as immersion gold, to form a first surface layer 80 on the first pad 20; after printing protective ink in the first area 111 using the first printing screen 40, the second pad 30 undergoes a second surface treatment, such as electroplating gold (gold on gold) to form a second surface layer on the second pad 30.

[0075] By adopting the above scheme, different surface treatment processes can be performed on the first pad 20 and the second pad 30 respectively.

[0076] It is understandable that after the second surface treatment of the second pad 30, the substrate 10 can continue to undergo molding, testing and FQC (Final Quality Control, outgoing inspection) processes.

[0077] In yet another embodiment, after printing protective ink in the first area 111 using the first printing screen 40, the PCB surface treatment method further includes:

[0078] First, the second pad 30 undergoes a third surface treatment, such as immersion gold treatment.

[0079] Next, remove the protective ink from the first area 111.

[0080] Finally, the first pad 20 undergoes a fourth surface treatment, such as OSP (Organic Solderability Preservatives) treatment.

[0081] By adopting the above scheme, different surface treatment processes can be performed on the first pad 20 and the second pad 30 respectively.

[0082] Secondly, embodiments of this application provide a PCB, which is manufactured according to the PCB surface treatment method of the first aspect.

[0083] The PCB provided in this embodiment has a windowed channel 41 in the first printing screen 40 used during processing. The windowed channel 41 includes a first channel 411 and a second channel 412 connected to the first channel 411. The first channel 411 corresponds to the first region 111, and the second channel 412 is located on the side of the first channel 411 closer to the second region 112. Therefore, when the first printing screen 40 prints protective ink on the first region 111 on the printing surface 11 of the substrate 10, the protective ink will flow onto the printing surface 11 through the windowed channel 41. Furthermore, since the first channel 411 has a first cross-section parallel to the printing surface 11, the perimeter of the first cross-section is... The ratio of the area of ​​the first cross section to the area of ​​the second channel 412 is D1. The cross section parallel to the printing surface 11 is the second cross section. The ratio of the perimeter of the second cross section to the area of ​​the second cross section is D2, where D2 > D1. Therefore, the flow rate of the protective ink flowing into the printing surface 11 through the first channel 411 is greater than that of the protective ink flowing into the printing surface 11 through the second channel 412. Thus, in the same amount of time, more protective ink flows into the first region 111 through the first channel 411, and less protective ink flows into the area around the first region 111 through the second channel 412. This reduces the risk of the protective ink penetrating into the second region 112 where the second pad 30 is located, thereby improving the quality of the PCB.

[0084] 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 PCB surface treatment method, characterized in that, include: A substrate is provided, the substrate having a printing surface, the printing surface including a first region and a second region spaced apart, a first pad being disposed in the first region and a second pad being disposed in the second region; Protective ink is printed in the first area using a first printing screen. The first printing screen is provided with a windowed channel, which includes a first channel and a second channel connected to the first channel. The first channel corresponds to the first area, and the second channel is located on the side of the first channel closer to the second area. The first channel has a first cross-section parallel to the printing surface, and the ratio of the perimeter of the first cross-section to the area of ​​the first cross-section is D1. The second channel has a second cross-section parallel to the printing surface, and the ratio of the perimeter of the second cross-section to the area of ​​the second cross-section is D2, where D2 > D1.

2. The PCB surface treatment method according to claim 1, characterized in that, The first cross section is rectangular in shape, and the second cross section is rhomboid or triangular in shape.

3. The PCB surface treatment method according to claim 1, characterized in that, The window opening channel includes a third channel connected to the first channel. The third channel and the second channel are located on both sides of the first channel. The third channel has a cross section parallel to the printing surface as a third cross section. The ratio of the perimeter of the third cross section to the area of ​​the third cross section is D3, where D3 < D1.

4. The PCB surface treatment method according to claim 3, characterized in that, The third cross section is circular or semi-circular in shape.

5. The PCB surface treatment method according to claim 1, characterized in that, Before printing protective ink on the first area using the first printing screen, a flow-blocking portion located between the first area and the second area is printed on the printing surface.

6. The PCB surface treatment method according to claim 5, characterized in that, The flow-blocking portion is configured as a groove, and the flow-blocking portion located between the first region and the second region is printed on the printing surface, including: A first solder resist ink is printed on the printing surface using a second printing screen, the second printing screen having a dotted strip located between the first region and the second region; The substrate is pre-baked; A second solder resist ink is printed on the first solder resist ink using a third printing screen, such that the groove is formed between the first region and the second region; Exposure and development expose the first pad and the second pad.

7. The PCB surface treatment method according to claim 5, characterized in that, The flow-blocking portion is configured as a protrusion, and the flow-blocking portion located between the first region and the second region is printed on the printing surface, including: A fourth printing screen is used to print a dam located between the first and second regions on the printing surface; The substrate is pre-baked; A fifth printing screen is used to print a third solder resist ink over the printing surface, the third solder resist ink covering the dam, so that the protrusion is formed between the first region and the second region; Exposure and development expose the first pad and the second pad.

8. The PCB surface treatment method according to any one of claims 1 to 7, characterized in that, Before printing protective ink on the first area using the first printing screen, the first pad undergoes a first surface treatment; After printing protective ink on the first area using a first printing screen, the second pad undergoes a second surface treatment.

9. The PCB surface treatment method according to any one of claims 1 to 7, characterized in that, After printing protective ink in the first area using a first printing screen, the PCB surface treatment method further includes: Perform a third surface treatment on the second pad; Remove the protective ink from the first area; The first pad is subjected to a fourth surface treatment.

10. A PCB, characterized in that, The PCB is manufactured according to the PCB surface treatment method as described in any one of claims 1 to 9.

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