Metallization via formation and circuit board

Abstract

The application relates to a metalized half-hole manufacturing method and a circuit board, wherein the metalized half-hole manufacturing method comprises the following steps: performing electroplating treatment on a circuit board semi-product with full holes; performing resin hole-plugging treatment on the circuit board semi-product after the electroplating treatment; manufacturing a groove body on the circuit board semi-product after the resin hole-plugging treatment; the groove body is arranged at a hole ring on one side of the half hole to be removed, divides the hole ring into two parts, is parallel to a forming line and is spaced apart from the forming line by a preset size in the width direction; performing dry film pasting treatment on one side of the half hole to be reserved along the forming line; performing etching treatment on the circuit board semi-product after the dry film pasting treatment; performing film removing treatment on the circuit board semi-product after the etching treatment; the copper thickness consumed in the etching treatment process corresponds to the interval size between the groove body and the forming line; removing the resin in the full hole of the circuit board semi-product after the film removing treatment; and performing edge milling treatment along the forming line. The metalized half-hole manufacturing method has the advantages of few defects.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of printed circuit board processing, in particular to a metalized half-hole manufacturing method and a circuit board. BACKGROUND

[0002] A printed circuit board (PCB) is also called a circuit board, which is made by using electronic printing technology. The printed circuit board is a support for electronic components and a carrier for electrical connection of electronic components, and plays a huge role in electronic products. For a type of circuit board that needs to install a printed connector or other components on the edge of the board, a metalized half-hole is generally designed on the edge of the board.

[0003] The traditional metalized half-hole manufacturing method directly cuts off the metalized full hole along the forming line by milling to form a metalized half-hole. In the milling process, the cutting effect occurs at the corner of the half-hole, which is prone to produce hole edge burrs, copper winding, and even copper pulling off the hole wall, thereby affecting the manufacturing quality of the half-hole corner and causing the metalized half-hole to be uneven. Therefore, the traditional metalized half-hole manufacturing method has the problem of many defects. SUMMARY

[0004] Therefore, it is necessary to provide a metalized half-hole manufacturing method and a circuit board to reduce defects and improve reliability in view of the above technical problems.

[0005] In a first aspect, the present application provides a metalized half-hole manufacturing method, comprising:

[0006] electroplating processing a circuit board semi-finished product with a full hole;

[0007] resin hole plugging processing the circuit board semi-finished product after electroplating processing;

[0008] manufacturing a groove on the circuit board semi-finished product after resin hole plugging; the groove is arranged at a hole ring on one side of the half-hole to be removed, divides the hole ring into two parts, and is parallel to the forming line and spaced apart from the forming line in the width direction by a preset size;

[0009] dry film processing is performed on one side of the half-hole to be retained along the forming line;

[0010] etching processing the circuit board semi-finished product after dry film processing; the copper thickness consumed in the etching processing process corresponds to the interval size between the groove and the forming line;

[0011] debinding processing the circuit board semi-finished product after etching processing;

[0012] removing the resin in the full hole of the circuit board semi-finished product after debinding processing;

[0013] milling along the forming line to remove the side of the half-hole that is not required to be retained.

[0014] In one embodiment, after the milling along the forming line to remove the side of the half-hole that is not required to be retained, the method further comprises:

[0015] micro-etching the circuit board with the metallized half-hole after the milling.

[0016] In one embodiment, when the circuit board semi-finished product with the full hole is subjected to the electroplating treatment, the copper thickness of the hole wall is increased by 10-20 μm based on the target copper thickness of the hole wall.

[0017] In one embodiment, the removing the resin in the full hole of the circuit board semi-finished product after the film stripping treatment comprises:

[0018] using a drill bit with the same diameter as the full hole to remove the resin in the full hole of the circuit board semi-finished product after the film stripping treatment.

[0019] In one embodiment, the preset size is 10-20 μm.

[0020] In one embodiment, the distance between the edge of the slot in the length direction and the closest hole ring edge is 0.2-1 mm.

[0021] In one embodiment, the slot is milled.

[0022] In one embodiment, two slots are formed on each full hole.

[0023] In one embodiment, when the circuit board semi-finished product after the dry film is attached is subjected to the etching treatment, a vibrating device is used to vibrate the etching chemical.

[0024] In a second aspect, the application provides a circuit board comprising a metallized half-hole made by the method for making a metallized half-hole as described above.

[0025] The above-described method for fabricating metallized half-holes first involves electroplating a semi-finished circuit board with full holes. Then, resin plugging is applied to the electroplated board to convert hollow holes into solid ones, reducing defects in the subsequent tank fabrication step. Next, the tank is fabricated, and the side of the half-hole to be retained is protected by applying a dry film. Etching is then performed to remove the copper from the half-hole ring and the copper between the tank and the forming line. After film removal, milling is performed. At this point, the hole ring and hole wall are no longer affected by the milling process; that is, milling only removes the dielectric layer, which helps reduce defects and improves process quality and reliability. The combination of these techniques effectively improves the fabrication quality and reliability of the metallized half-holes, providing a good foundation for subsequent soldering. Attached Figure Description

[0026] Figure 1 This is a flowchart illustrating a method for fabricating a metallized half-hole in one embodiment;

[0027] Figure 2 This is a flowchart illustrating the method for fabricating aluminum metallized semi-holes in another embodiment;

[0028] Figure 3 This is a schematic diagram of the structure of a semi-finished circuit board with full holes after electroplating and resin plugging in one embodiment.

[0029] Figure 4 for Figure 3 A schematic diagram of the structure of the semi-finished circuit board after the tank is made;

[0030] Figure 5 for Figure 4 A schematic diagram of the structure of a semi-finished circuit board after dry film has been applied;

[0031] Figure 6 for Figure 5 Schematic diagram of the AA section of the semi-finished circuit board;

[0032] Figure 7 for Figure 6 A schematic diagram of the structure of the semi-finished circuit board after etching and film removal;

[0033] Figure 8 for Figure 7 A schematic diagram of the structure of the semi-finished circuit board after resin removal;

[0034] Figure 9 for Figure 8 A schematic diagram of the structure of the semi-finished circuit board after edge milling;

[0035] Figure 10 for Figure 9 A schematic diagram of the structure of the circuit board after micro-etching.

[0036] Explanation of reference numerals: 10 - first full hole, 11 - hole wall, 12 - hole ring, 13 - resin, 14 - half-hole corner, 15 - groove body, 20 - second full hole, 30 - circuit board body, 40 - molding line, 50 - first dry film, 60 - second dry film, 70 - medium layer, 80 - board edge, 90 - burr. DETAILED DESCRIPTION

[0037] For the purpose of understanding the present application, the present application will be described in more detail by referring to the attached drawings. The embodiments of the present application are shown in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs. The terminology used in the description of the present application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application.

[0039] It is to be understood that the terms "first", "second", and the like, used herein do not denote any quantity or order, but are used to distinguish one element from another. For example, a first protective layer can be referred to as a second protective layer, and similarly, a second protective layer can be referred to as a first protective layer, without departing from the scope of the present application. The first protective layer and the second protective layer are both protective layers, but they are not the same protective layer.

[0040] As used herein, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise. It is also to be understood that the term "comprising" or "including" or "having" or the like, means the presence of stated features, integers, steps, operations, components, parts, or combinations thereof, but does not preclude the presence or addition of one or more other features, integers, steps, operations, components, parts, or combinations thereof.

[0041] In addition, in the present patent, unless otherwise clearly specified and limited, the first feature is "on" or "under" the second feature, which can be directly in contact with the first and second features, or indirectly in contact with the first and second features through an intermediate medium. Moreover, the first feature "above", "over" and "on" the second feature can be directly above or obliquely above the second feature, or simply means that the first feature is higher in horizontal height than the second feature. The first feature "below", "under" and "under" the second feature can be directly below or obliquely below the second feature, or simply means that the first feature is lower in horizontal height than the second feature.

[0042] In a first aspect, the application provides a method for manufacturing a metalized half-hole, which will be described below with reference to the accompanying drawings. Figure 1 In one embodiment, the method comprises steps S10 to S80.

[0043] Step S10: electroplating a circuit board semi-product with full holes.

[0044] Step S20: resin hole-plugging the circuit board semi-product after the electroplating.

[0045] Step S30: manufacturing a groove on the circuit board semi-product after the resin hole-plugging; the groove is arranged at a hole ring on one side of the half-hole to be removed, which divides the hole ring into two parts, and is parallel to the forming line and spaced from the forming line by a preset size in the width direction.

[0046] Step S40: dry film pasting on one side of the half-hole to be retained along the forming line.

[0047] Step S50: etching the circuit board semi-product after the dry film pasting.

[0048] Step S60: film removal of the circuit board semi-product after the etching; the copper thickness consumed in the etching process corresponds to the interval size between the groove and the forming line.

[0049] Step S70: removing the resin in the full hole of the circuit board semi-product after the film removal.

[0050] Step S80: edge milling along the forming line.

[0051] The above method for manufacturing a metalized half-hole first electroplates a circuit board semi-product with full holes, then resin hole-plugs the circuit board semi-product after the electroplating to change the hollow hole into a solid hole, reducing defects in the next step of manufacturing the groove. Then the groove is manufactured, and the half-hole side to be retained is protected by pasting a dry film, and then etching is performed to remove the hole copper on the hole ring of the half-hole while removing the hole copper between the groove and the forming line. After the film removal, edge milling is performed, at this time, the hole ring and the hole wall are no longer affected by the edge milling process, that is, at this time, the edge milling only mills the dielectric layer, which is beneficial to reduce defects and improve process quality and reliability. The above techniques cooperate to effectively improve the manufacturing quality and reliability of the metalized half-hole, and provide a good half-hole foundation for subsequent welding.

[0052] In one embodiment, as shown in FIG. 1, the method further comprises step S90 after step S80. Figure 2

[0053] Step S90: micro-etching the circuit board with the metalized half-hole obtained after the edge milling. ​

[0054] In the above embodiments, after milling, the metallized half-hole undergoes micro-etching to smooth the rough surface inside the hole, making the hole wall smooth. This helps to further improve the manufacturing quality of the metallized half-hole, enhance its reliability, and provide a good foundation for subsequent welding.

[0055] The following is a detailed explanation with reference to the accompanying drawings.

[0056] It should be noted that a semi-finished circuit board with full holes may contain one, two, or more full holes; this application does not limit the specific number of full holes. Furthermore, a half-hole is an incomplete through-hole relative to a full hole. The curvature value of the surface in a half-hole can be any value below 360°; this application does not limit the curvature value of the surface in a half-hole. For ease of understanding, the following explanation assumes two full holes and a half-hole with a curvature value of 180° to be retained.

[0057] like Figure 3 As shown, a circuit board semi-finished product with a first full hole 10 and a second full hole 20 is shown. The area outside the two full holes in the circuit board semi-finished product is called the circuit board body 30. Figure 3 In this circuit board, the forming line 40 coincides with the diameter of the first full hole 10 and the second full hole 20, and the area below the forming line 40 is the area that needs to be retained. First, the circuit board semi-finished product is electroplated to coat the hole walls 11 and hole rings 12 of the first full hole 10 and the second full hole 20 with copper, forming metallized full holes. Then, the metallized full holes are resin-filled: the holes are filled with resin ink and baked to cure, filling the holes with cured resin 13. This transforms the first full hole 10 and the second full hole 20 from hollow holes into solid holes, preventing burrs or copper curl at the corners 14 of the half-holes during subsequent milling. Optionally, in one embodiment, during electroplating, the copper thickness of the hole wall is increased by 10μm to 20μm based on the target hole wall copper thickness to offset the loss of copper thickness in the hole wall 11 during subsequent removal of the resin 13.

[0058] like Figure 4As shown, grooves 15 are made on the hole ring 12 of the side of the semi-hole to be removed, the hole ring 12 of the full hole is divided into two, and the grooves 15 are parallel to the forming line 40 and are spaced apart from the forming line 40 in the width direction by a predetermined size. The spacing size between the grooves 15 and the forming line 40 corresponds to the copper thickness consumed in the subsequent etching process. The number of grooves 15 can be the same as the number of full holes or the same as the number of forming lines 40 to improve processing efficiency. Preferably, the spacing size between the grooves 15 and the forming line 40 is 10 μm-20 μm to facilitate the adjustment of the subsequent etching process parameters. Preferably, the distance between the length direction edge of the groove 15 and the edge of the closest hole ring 12 is 0.2 mm-1 mm to make the groove 15 not affect the stability of the overall structure of the circuit board in the subsequent process.

[0059] Preferably, two independent grooves 15 are made on each full hole, that is, the two grooves on the same full hole are not through. On the one hand, it can avoid the excessive flow of the drug through the groove during the subsequent etching, weaken the effect of drug exchange, and be not conducive to etching the copper plating on the hole wall in the groove; on the other hand, such design has the least impact on the structural stability of the position where the groove is located, can reduce the possibility of expansion or warping in the subsequent processing process, and avoid poor milling precision caused by uneven stress during milling, thereby affecting the overall processing quality.

[0060] Please continue to refer to Figure 4 In one embodiment, the milling groove processing method is used to make two independent grooves 15 on each full hole, and the width of the grooves 15 is consistent with the milling cutter processing width, that is, one pass of the cutter completes the processing of one groove 15. The distance between the length direction edge of the groove 15 and the edge of the closest hole ring 12 is 0.2 mm-1 mm, and the distance between the width direction edge of the groove 15 and the forming line 40 is 10 μm-20 μm.

[0061] As shown in Figure 5 As shown, dry film is attached to the side of the semi-hole to be retained along the forming line 40, and the dry film covers the entire area of the circuit board to be retained. Figure 6 In Figure 5 The cross-sectional view of A-A. As shown in Figure 6 The upper and lower surfaces of the side of the semi-hole to be retained are covered by the first dry film layer 50 and the second dry film layer 60. Figure 6 The thick solid line in the figure is the edge of the groove 15 in the width direction, and it can be seen that each groove 15 penetrates through the entire circuit board body 30, so that the copper plating on the entire hole wall 11 in the thickness direction is exposed to the groove 15. In the figure, 70 is a dielectric layer.

[0062] The circuit board with the above structure is etched. On one hand, the electroplated copper on the hole ring 12 of the half-hole to be removed is etched away; on the other hand, the electroplated copper on the inner wall 11 of the tank 15 is etched away along the AA cross-section direction. The copper thickness consumed during the etching process corresponds to the interval between the tank 15 and the forming line 40. Preferably, a vibration device can be used to vibrate the etching solution during the etching process to improve the etching uniformity of the electroplated copper on the hole wall 11 along the depth direction of the tank 15. The etched circuit board semi-finished product is then subjected to a stripping process to remove the first dry film layer 50 and the second dry film layer 60, resulting in the circuit board as shown in the image. Figure 7 The structure shown. (As illustrated) Figure 7 As shown, after etching, the electroplated copper on the hole wall 11 between the tank 14 and the forming line 40 is removed. By etching away the copper on the hole wall, only the dielectric layer 70 is milled away during edge milling, avoiding problems such as copper curling and burrs caused by direct edge milling, and making the copper on the hole wall smooth.

[0063] After removing resin 13 from all the holes of the semi-finished circuit board after the delamination process, a shape like... Figure 8 The structure shown. The method for removing resin 13 can be either mechanical processing or chemical processing. Preferably, when the electroplating thickness is 10μm to 20μm, the resin inside the hole is drilled away using a drill bit with the same diameter as the hole. In this way, the thickened electroplated copper on the hole wall 11 can act as a thin layer of copper that is removed, thus protecting the electroplated copper that needs to be left.

[0064] like Figure 9 As shown, milling is performed along the forming line 40 to remove the side of the half-hole that does not need to be retained, thus retaining the metallized half-hole required below the plate edge 80, and completing the production of the metallized half-hole.

[0065] Finally, as Figure 10 As shown, micro-etching is performed to repair and remove the rough surface of the hole wall 11 formed during resin 13 removal, i.e. Figure 9 The burrs 90 in the hole make the hole wall 11 smooth, which is beneficial to further improve the processing quality.

[0066] In the above embodiment, firstly, the circuit board semi-product with full holes is subjected to electroplating treatment, then the circuit board semi-product after electroplating treatment is subjected to resin hole filling treatment, the hollow hole is changed into a solid hole, and the defect in the next step of manufacturing the groove body is reduced. Then the groove body is manufactured, the dry film is pasted to protect the side of the semi-hole to be reserved, and then etching treatment is performed, the hole copper on the semi-hole ring is removed, and the hole copper between the groove body and the forming line is removed. After the film removal treatment, milling edge treatment is performed, at this time, the hole ring and the hole wall are no longer affected by the milling edge process, that is, at this time, the milling edge only mills the dielectric layer, which is beneficial to reduce defects and improve process quality and reliability. After the milling edge treatment, the metalized semi-hole is subjected to micro-etching treatment, and the rough surface in the hole is trimmed to make the hole wall smooth. The above technologies are combined to effectively improve the manufacturing quality and reliability of the metalized semi-hole, and provide a good semi-hole foundation for subsequent welding.

[0067] In a second aspect, the application provides a circuit board comprising the metalized semi-hole manufactured by the method in the above embodiment. Specifically, the circuit board can be a single-sided board or a double-sided board, and can also be a multi-layer board. The metalized semi-hole in the circuit board can be one or multiple. It can be understood that according to different actual circuit designs, other structures of the circuit board can also be manufactured by using other processes before and / or after the metalized semi-hole is manufactured, so as to complete the entire circuit manufacturing of the circuit board.

[0068] The above circuit board, since in the manufacturing of the metalized semi-hole, firstly, the circuit board semi-product with full holes is subjected to electroplating treatment, then the circuit board semi-product after electroplating treatment is subjected to resin hole filling treatment, the hollow hole is changed into a solid hole, and the defect in the next step of manufacturing the groove body is reduced. Then the groove body is manufactured, the dry film is pasted to protect the side of the semi-hole to be reserved, and then etching treatment is performed, the hole copper on the semi-hole ring is removed, and the hole copper between the groove body and the forming line is removed. After the film removal treatment, milling edge treatment is performed, at this time, the hole ring and the hole wall are no longer affected by the milling edge process, that is, at this time, the milling edge only mills the dielectric layer, which is beneficial to reduce defects and improve process quality and reliability. The above technologies are combined to effectively improve the manufacturing quality and reliability of the metalized semi-hole, and provide a good semi-hole foundation for subsequent welding.

[0069] The technical features of the above embodiments can be combined in any manner. In order to make the description concise, all possible combinations of the technical features in the above embodiments are not described, however, as long as the combinations of the technical features do not exist contradictions, they should be considered as the scope of the present application.

[0070] The above embodiment only expresses several implementation manners of the application, and the description is more specific and detailed, but it cannot be understood as a limitation on the scope of the patent. It should be pointed out that for ordinary skilled persons in the art, several modifications and improvements can be made without departing from the concept of the application, and these all belong to the protection scope of the application. Therefore, the protection scope of the patent of the application should be subject to the appended claims.

Claims

1. A method for fabricating a metallized semi-hole, characterized in that, include: Electroplating is performed on semi-finished circuit boards with full holes. When electroplating the semi-finished circuit board with full holes, the copper thickness of the hole wall is increased by 10μm~20μm based on the target copper thickness of the hole wall; The electroplated circuit board semi-finished product is then subjected to resin plugging treatment. A groove is fabricated on the circuit board semi-finished product after resin plugging; The groove is set at the annular hole on one side of the half hole to be removed, dividing the annular hole into two parts, and is parallel to the forming line with a preset size gap between it and the forming line in the width direction; Apply dry film along the molding line to the side of the half-hole that needs to be retained. The circuit board semi-finished product after applying dry film is etched; the copper thickness consumed during the etching process corresponds to the spacing between the groove and the forming line. The etched circuit board semi-finished product is then subjected to a film removal process. Remove the resin from all the holes of the circuit board semi-finished product after the delamination process; The removal of resin from the full-hole portion of the circuit board semi-finished product after the film removal process includes: using a drill bit with the same diameter as the full-hole portion to remove the resin from the full-hole portion of the circuit board semi-finished product after the film removal process; Milling is performed along the forming line to remove the side of the half-hole that does not need to be retained. After milling along the forming line to remove the unwanted half-hole side, the process further includes micro-etching the resulting circuit board with the metallized half-hole.

2. The method for fabricating a metallized semi-hole according to claim 1, characterized in that, The preset size is 10μm~20μm.

3. The method for fabricating a metallized semi-hole according to claim 1, characterized in that, The distance between the edge of the groove along its length and the edge of the nearest annular hole is 0.2mm to 1mm.

4. The method for fabricating a metallized semi-hole according to claim 1, characterized in that, The groove is manufactured by milling.

5. The method for fabricating a metallized semi-hole according to any one of claims 2 to 4, characterized in that, Two independent grooves are made on each of the full holes.

6. The method for fabricating a metallized semi-hole according to claim 1, characterized in that, When etching the circuit board semi-finished product after applying the dry film, a vibration device is used to vibrate the etching solution.

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