Circuit board manufacturing method and circuit board to prevent repeated drilling during back drilling
By machining small holes first and then large holes in the test holes of the circuit board, the problem of circuit board scrapping caused by repeated drilling during back drilling was solved, and efficient production of circuit boards and accurate control of equipment were achieved.
Patent Information
- Application Number
- CN202510073549.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-16
- Publication Date
- 2025-10-31
- Estimated Expiration
- 2045-01-16
AI Technical Summary
During back drilling, the problem of repeated drilling causing circuit board scrapping cannot be effectively avoided by existing technologies.
The first hole is machined at the test hole position on the circuit board, with a depth less than or equal to the substrate thickness. Then, the electroplated through hole is back-drilled. Finally, the second hole is machined at the test hole position. The second hole is coaxial with the first hole and has a larger diameter than the first hole, penetrating the substrate to ensure that the drilling equipment cannot form an induction circuit and avoid repeated drilling.
By using a double-drilling design for the test holes, the scrapping of circuit boards caused by repeated drilling is avoided, production efficiency and drilling equipment accuracy are improved, and the need for manual intervention is reduced.
Smart Images
Figure CN119997366B_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of printed circuit boards, and more particularly to a method for manufacturing a circuit board and a circuit board for preventing repeated drilling via back drilling. Background Technology
[0002] With the development of 5G communication technology, interference from circuit boards, such as reflection, scattering, and delay, can cause signal distortion and affect signal integrity. To reduce signal distortion, a back-drilling process is needed to remove excess copper from the walls of electroplated through-holes, ensuring signal integrity.
[0003] Back drilling involves using a drilling machine to precisely remove unwanted portions of copper from an electroplated through-hole through a controlled-depth drilling process. These unwanted portions are called stubs. Because the controlled-depth setting keeps the stub within the required range, the stub will be drilled to a fixed depth as the drill tip probes the zero point.
[0004] Normally, the zero position is calculated when the drill tip contacts the copper layer on the circuit board and forms a circuit with the mushroom head. However, when repeated drilling occurs due to human factors, the circuit will calculate the zero position when the drill tip drills into an already drilled electroplated through hole. The zero position is calculated based on the collision of the drill bit side edge with the surface copper of the electroplated through hole. Due to the different sensing positions, the depth changes, and the excess length cannot be controlled within the required range, which leads to the scrapping of the circuit board. Summary of the Invention
[0005] This application provides a method for manufacturing a circuit board and a circuit board that prevents repeated drilling during back drilling, which can improve the problem of circuit board scrapping caused by repeated drilling during back drilling.
[0006] In a first aspect, embodiments of this application provide a method for manufacturing a circuit board to prevent repeated drilling via back drilling, comprising:
[0007] A substrate is provided, the substrate including test holes and a back-drilling area, the test holes being conductive, and the back-drilling area having electroplated through holes to be back-drilled.
[0008] A first hole is machined at the test hole position, and the depth of the first hole is less than or equal to the thickness of the substrate;
[0009] The electroplated through holes are back-drilled.
[0010] A second hole is machined at the test hole position. The second hole is coaxially arranged with the first hole. The diameter of the second hole is larger than that of the first hole. The second hole penetrates the substrate.
[0011] In some embodiments, the depth of the first hole is 1 / 3 to 1 / 2 of the thickness of the substrate.
[0012] In some embodiments, multiple test holes and back-drilled areas are provided, with one back-drilled area corresponding to at least one test hole.
[0013] In some embodiments, M test holes are provided, and N back-drilling areas are provided, where M and N are both positive integers greater than or equal to 2; after providing the substrate, the method for manufacturing the circuit board to prevent repeated back-drilling includes:
[0014] The first hole is machined at the (N-1)th test hole position, and the depth of the first hole is less than or equal to the thickness of the substrate;
[0015] The electroplated through hole in the M-1th back-drilled area is back-drilled;
[0016] A second hole is machined at the N-1th test hole position. The second hole is coaxially arranged with the first hole. The diameter of the second hole is larger than that of the first hole. The second hole penetrates the substrate.
[0017] The first hole is machined at the Nth test hole position, and the depth of the first hole is less than or equal to the thickness of the substrate;
[0018] The electroplated through hole in the Mth back-drilled region is back-drilled;
[0019] A second hole is machined at the Nth test hole position. The second hole is coaxially arranged with the first hole. The diameter of the second hole is larger than that of the first hole. The second hole penetrates the substrate.
[0020] In some embodiments, the diameter of the first hole is 0.3mm-1.0mm, and the diameter of the second hole is greater than 1.0mm.
[0021] In some embodiments, the diameter of the first hole is 0.5 mm, and the diameter of the second hole is 3.1 mm.
[0022] In some embodiments, a first drill bit is used to machine a first hole at the test hole location; before back drilling the electroplated through hole, a lettering hole is machined on the substrate using the first drill bit.
[0023] In some embodiments, a second drill bit is used to machine a second hole at the test hole location; after back-drilling the electroplated through hole, an identification hole is machined on the substrate using the second drill bit.
[0024] In some embodiments, the test hole is located on the process edge of the substrate.
[0025] Secondly, embodiments of this application provide a circuit board manufactured by the circuit board manufacturing method for preventing repeated drilling by back drilling as described in the first aspect.
[0026] The circuit board manufacturing method for preventing repeated drilling provided in this application has the following advantages: First, a first hole is machined at the test hole position, and the depth of the first hole is less than or equal to the thickness of the substrate. Then, the electroplated through hole is back-drilled. Finally, a second hole is machined at the test hole position, and the second hole is coaxially arranged with the first hole. The diameter of the second hole is larger than that of the first hole, and the second hole penetrates the substrate. Therefore, when the substrate is not removed from the board and repeated drilling is performed, the drilling start position is the test hole position. Since the test hole position has been drilled through by the second hole, the drill bit of the drilling equipment cannot contact any conductive part on the substrate, and thus cannot form a sensing circuit. The drilling equipment cannot sense and will stop and alarm. The stop alarm information of the drilling equipment can be checked manually and the problem of substrate scrapping due to repeated drilling can be detected in time.
[0027] 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 circuit board manufacturing method for preventing repeated drilling by back drilling compared to the prior art, which will not be repeated here. Attached Figure Description
[0028] 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.
[0029] Figure 1 This is a flowchart of a circuit board manufacturing method for preventing repeated drilling via back drilling in one embodiment of this application;
[0030] Figure 2 This is a schematic diagram of the substrate structure in one embodiment of this application;
[0031] Figure 3 Is Figure 2 The diagram shows a test hole on the substrate where the first hole is machined.
[0032] Figure 4 Yes Figure 2 A schematic diagram showing the back-drilling process performed on the electroplated through-holes of the substrate shown.
[0033] Figure 5 Is Figure 4 The diagram shows a second hole being machined into the test hole position of the substrate.
[0034] The markings in the diagram mean:
[0035] 100. Substrate;
[0036] 10. Test hole; 20. Electroplating through hole; 30. First hole; 40. Second hole. Detailed Implementation
[0037] 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.
[0038] 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.
[0039] 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.
[0040] 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.
[0041] To illustrate the technical solution of this application, the following description is provided in conjunction with specific accompanying drawings and embodiments.
[0042] With the development of 5G communication technology, interference from circuit boards, such as reflection, scattering, and delay, can cause signal distortion and affect signal integrity. To reduce signal distortion, a back-drilling process is needed to remove excess copper from the walls of electroplated through-holes, ensuring signal integrity.
[0043] Back drilling involves using a drilling machine to precisely remove unwanted portions of copper from an electroplated through-hole through a controlled-depth drilling process. These unwanted portions are called stubs. Because the controlled-depth setting keeps the stub within the required range, the stub will be drilled to a fixed depth as the drill tip probes the zero point.
[0044] Normally, the zero position is calculated when the drill tip contacts the copper layer on the circuit board and forms a circuit with the mushroom head. However, when repeated drilling occurs due to human factors, the circuit will calculate the zero position when the drill tip drills into an already drilled electroplated through hole. The zero position is calculated based on the collision of the drill bit side edge with the surface copper of the electroplated through hole. Due to the different sensing positions, the depth changes, and the excess length cannot be controlled within the required range, which leads to the scrapping of the circuit board.
[0045] In view of this, this application provides a circuit board manufacturing method and circuit board to prevent repeated drilling by back drilling. First, a first hole is machined at the test hole position. The depth of the first hole is less than or equal to the thickness of the substrate. Then, the electroplated through hole is back drilled. Finally, a second hole is machined at the test hole position. The second hole is coaxial with the first hole. The diameter of the second hole is larger than that of the first hole. The second hole penetrates the substrate. Therefore, when the substrate is not removed and repeated drilling is performed, the drilling start position is the test hole position. Since the test hole position has been drilled through by the second hole, the drill bit of the drilling equipment cannot contact any conductive part on the substrate. Therefore, a sensing circuit cannot be formed. The drilling equipment cannot sense and will stop and alarm. The stop alarm information of the drilling equipment can be checked manually and the problem of substrate scrapping due to repeated drilling can be detected in time.
[0046] Please refer to Figures 1 to 5 , Figure 1 This is a flowchart of a circuit board manufacturing method for preventing repeated drilling via back drilling, as described in one embodiment of this application. Figure 2 This is a schematic diagram of the structure of the substrate 100 in one embodiment of this application. Figure 3 Is Figure 2 The diagram shows the test hole position 10 of the substrate 100 where the first hole 30 is machined. Figure 4 Yes Figure 2 A schematic diagram showing the back-drilling process performed on the electroplated through-holes 20 of the substrate 100. Figure 5 Is Figure 4 The diagram shows a second hole 40 being machined into the test hole position 10 of the substrate 100.
[0047] In a first aspect, embodiments of this application provide a method for manufacturing a circuit board to prevent repeated drilling via back drilling, comprising:
[0048] S100: A substrate 100 is provided. The substrate 100 includes a test hole 10 and a back-drilling area. The test hole 10 is conductive. The back-drilling area is provided with an electroplated through hole 20 to be back-drilled.
[0049] Specifically, multiple test holes 10 and back-drilled areas are provided. The substrate 100 may include multiple circuit layers, which may be copper layers. The inner wall of the electroplated through-hole 20 is provided with a conductive layer, which may also be a copper layer. The copper in the hole is electrically connected to at least two circuit layers. The substrate 100 may be provided with surface copper, which includes the test holes 10.
[0050] It is understandable that the test hole 10 can be located on the process edge of the substrate 100 or other areas where no circuitry is provided.
[0051] S200: A first hole 30 is machined at the test hole position 10, and the depth of the first hole 30 is less than or equal to the thickness of the substrate 100.
[0052] Specifically, the drill bit of the drilling equipment can be used to process the first hole 30 at the test hole position 10. When the drill tip of the drill bit contacts the test hole position 10 and forms a circuit with the mushroom head, the zero position is calculated and the first hole 30 of the preset depth is processed.
[0053] It is understood that when the depth of the first hole 30 is less than the thickness of the substrate 100, the first hole 30 is a blind hole; when the depth of the first hole 30 is equal to the thickness of the substrate 100, the first hole 30 is a through hole. In the illustrated embodiment, the first hole 30 is a blind hole.
[0054] S300: Back-drilling is performed on the electroplated through hole 20.
[0055] Specifically, another drill bit of the drilling equipment can be used to back-drill the electroplated through hole 20. The side edge of the drill bit hits the copper surface layer of the hole wall of the electroplated through hole 20 to calculate the zero position, thereby back-drilling the electroplated through hole 20.
[0056] For example, the production data is set, the drill bits are arranged, the conductive mushroom head is pressed onto the surface of the substrate 100 to conduct electricity, and the production is started. The drilling equipment senses the height of the board surface (the zero point of the back drilling depth) based on the circuit formed by the drill tip, the surface of the substrate 100 (copper surface), and the conductive mushroom head. The equipment drills down to the preset depth set in the data to perform back drilling on the electroplated through hole 20. After the drilling equipment completes the program, a stop alarm indicates that the program is 100% complete.
[0057] S400: A second hole 40 is machined in the test hole position 10. The second hole 40 is coaxially arranged with the first hole 30. The diameter of the second hole 40 is larger than the diameter of the first hole 30. The second hole 40 penetrates the substrate 100.
[0058] Specifically, a second hole 40 can be machined at the test hole position 10 using another drill bit of the drilling equipment. The inner wall of the second hole 40 is not conductive.
[0059] It is understandable that after back-drilling all the electroplated through holes 20 in the back-drilled area, the second hole 40 is then drilled in the test hole position 10. The drilling sequence on the substrate 100 starts with controlling the depth of the first hole 30 at the test hole position 10 and ends with drilling the second hole 40 at the test hole position 10.
[0060] It is also understandable that the normal production process involves manually removing the substrate 100 that has already undergone back drilling and then re-processing it on a substrate 100 that has not undergone back drilling. However, if, due to human error, the substrate 100 that has already undergone back drilling is not removed and the machine is started directly for repeated drilling, the drilling starts at the test hole position 10. Since the test hole position 10 has already been drilled through by the second hole 40, the drill bit of the drilling equipment for processing the first hole 30 cannot contact any conductive part on the substrate 100. Therefore, the circuit cannot be effectively closed, and the zero position of the board surface sensed by the drilling equipment cannot be triggered. The drilling equipment stops and alarms, indicating that the drilling position height is out of tolerance. This can be detected in time by manually checking the drilling equipment stop alarm information, thereby avoiding the quality risks caused by the inconsistent zero position of the board surface sensed by the drilling equipment due to repeated back drilling.
[0061] As can be seen from the above, the circuit board manufacturing method for preventing repeated drilling provided in this application first processes a first hole 30 in the test hole position 10, the depth of the first hole 30 being less than or equal to the thickness of the substrate 100. Then, the electroplated through hole 20 is back-drilled. Finally, a second hole 40 is processed in the test hole position 10, and the second hole 40 is coaxially arranged with the first hole 30. The diameter of the second hole 40 is larger than the diameter of the first hole 30. The second hole 40 penetrates the substrate 100. Therefore, when the substrate 100 is not removed from the board and repeated drilling occurs, the drilling starts at the test hole position 10. Since the test hole position 10 has been drilled through by the second hole 40, the drill bit of the drilling equipment cannot contact any conductive part on the substrate 100, and thus cannot form a sensing circuit. The drilling equipment cannot sense and will stop and alarm. The stop alarm information of the drilling equipment can be checked manually and the problem of the substrate 100 being scrapped due to repeated drilling can be avoided in time.
[0062] The circuit board manufacturing method for preventing repeated back-drilling provided in this application can improve the problem that the substrate 100 is repeatedly back-drilled due to human factors and cannot be accurately identified, resulting in the scrapping of the substrate 100. It can also ensure that the sensing height of the drilling equipment is on the surface of the substrate 100, ensure that the back-drilling depth is fixed, and at the same time, the sensing height of the drilling equipment is not misled, and the excess length stub is controlled within the production range.
[0063] Optionally, the first hole 30 is machined in the test hole position 10, the electroplated through hole 20 is back-drilled, and the second hole 40 is machined in the test hole position 10, all from the same side of the substrate 100.
[0064] This configuration avoids flipping the substrate 100 during processing, thereby improving production efficiency.
[0065] The depth of the first hole 30 is 1 / 3 to 1 / 2 of the thickness of the substrate 100.
[0066] This design avoids the first hole 30 being too deep, which would affect drilling efficiency, and also avoids the first hole 30 being too shallow, which would prevent the drill bit side edge from entering the substrate 100.
[0067] Optionally, multiple test holes 10 and back-drilled areas are provided, with each back-drilled area corresponding to at least one test hole 10.
[0068] This setup avoids the problem of substrate 100 being scrapped due to repeated drilling.
[0069] In this embodiment, M test holes are set, and N back-drilling areas are set, where M and N are both positive integers greater than or equal to 2.
[0070] After providing the substrate 100, the circuit board manufacturing method to prevent repeated drilling via back drilling includes:
[0071] First, a first hole 30 is machined at the N-1th test hole position 10, and the depth of the first hole 30 is less than or equal to the thickness of the substrate 100.
[0072] Next, the electroplated through hole 20 in the M-1th back-drilled area is back-drilled.
[0073] Next, a second hole 40 is machined at the N-1 test hole position 10. The second hole 40 is coaxially arranged with the first hole 30. The diameter of the second hole 40 is larger than the diameter of the first hole 30. The second hole 40 penetrates the substrate 100.
[0074] Next, a first hole 30 is machined at the Nth test hole position 10, and the depth of the first hole 30 is less than or equal to the thickness of the substrate 100.
[0075] Then, the electroplated through hole 20 in the Mth back-drilled area is back-drilled.
[0076] Finally, a second hole 40 is machined at the Nth test hole position 10. The second hole 40 is coaxially arranged with the first hole 30. The diameter of the second hole 40 is larger than that of the first hole 30. The second hole 40 penetrates the substrate 100.
[0077] By adopting the above scheme, it is possible to simultaneously monitor whether multiple back-drilling areas are being drilled repeatedly.
[0078] It should be noted that the substrate 100 may include multiple sets (finished product shipping units), and the number of test hole positions 10 is set according to the number of sets. One test hole position 10 is set for each set. During drilling, the first hole 30 of the test hole position 10 corresponding to the first set is drilled with controlled depth first, then the back drilling of the electroplated through hole 20 in the back drilling area of the first set is completed, and finally the second hole 40 of the test hole position 10 corresponding to the first set is drilled. Then the first hole 30 of the test hole position 10 corresponding to the second set is drilled with controlled depth, and so on.
[0079] Optionally, the diameter of the first hole 30 is 0.3mm-1.0mm, and the diameter of the second hole 40 is greater than 1.0mm.
[0080] This configuration improves drilling efficiency and avoids the first hole 30 and the second hole 40 occupying a large space on the substrate 100.
[0081] For example, the diameter of the first hole 30 is 0.5 mm, and the diameter of the second hole 40 is 3.1 mm.
[0082] This configuration improves drilling efficiency and avoids the first hole 30 and the second hole 40 occupying a large space on the substrate 100.
[0083] Please refer to Figure 2 and Figure 3 In this embodiment, a first hole 30 is machined in the test hole position 10 using a first drill bit; before back drilling the electroplated through hole 20, a letter mark hole is machined on the substrate 100 using the first drill bit.
[0084] By adopting the above scheme, the first drill bit can be shared for machining the first hole 30 and machining the marking hole, saving the tool changing time of the drilling equipment and improving drilling efficiency.
[0085] It is understandable that, compared to using other drill bits to process marking holes on the substrate 100, this embodiment of the application can use one less drill bit, thus saving costs.
[0086] Optionally, a second hole 40 is machined in the test hole position 10 using a second drill bit; after back drilling the electroplated through hole 20, an identification hole is machined on the substrate 100 using a second drill bit.
[0087] This configuration allows the second drill bit to be shared for machining the second hole 40 and the identification hole, saving tool change time and improving drilling efficiency.
[0088] It is understood that the identification hole can be a hole used to identify the direction of the substrate 100. Compared with using other drill bits to process the identification hole on the substrate 100, the embodiment of this application can use one less drill bit, which can save costs.
[0089] Optionally, the test hole 10 is located on the process edge of the substrate 100.
[0090] This setting can prevent the subsequent second hole 40 from affecting the normal circuit layout of the circuit board.
[0091] Secondly, embodiments of this application provide a circuit board manufactured by a circuit board manufacturing method for preventing repeated drilling via back drilling as described in the first aspect.
[0092] The circuit board provided in this application embodiment first processes a first hole 30 in the test hole position 10, the depth of the first hole 30 being less than or equal to the thickness of the substrate 100. Then, the electroplated through hole 20 is back-drilled. Finally, a second hole 40 is processed in the test hole position 10, and the second hole 40 is coaxially arranged with the first hole 30. The diameter of the second hole 40 is larger than the diameter of the first hole 30. The second hole 40 penetrates the substrate 100. Therefore, when the substrate 100 is not removed and drilling is repeated, the drilling start position is the test hole position 10. Since the test hole position 10 has been drilled through by the second hole 40, the drill bit of the drilling equipment cannot contact any conductive part on the substrate 100, and thus cannot form a sensing circuit. The drilling equipment cannot sense and will stop and alarm. The stop alarm information of the drilling equipment can be checked manually and the problem of the substrate 100 being scrapped due to repeated drilling can be avoided.
[0093] 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 to prevent repeated drilling via back drilling, characterized in that, include: A substrate is provided, the substrate including test holes and a back-drilling area, the test holes being conductive, and the back-drilling area having electroplated through holes to be back-drilled. A first hole is machined at the test hole position, and the depth of the first hole is less than or equal to the thickness of the substrate; The electroplated through holes are back-drilled. A second hole is machined at the test hole position. The second hole is coaxially arranged with the first hole. The diameter of the second hole is larger than that of the first hole. The second hole penetrates the substrate. The inner wall of the second hole is not conductive.
2. The circuit board manufacturing method for preventing repeated drilling via back drilling according to claim 1, characterized in that, The depth of the first hole is 1 / 3 to 1 / 2 of the thickness of the substrate.
3. The circuit board manufacturing method for preventing repeated drilling via back drilling according to claim 1, characterized in that, Multiple test holes and multiple back-drilling areas are provided, and each back-drilling area corresponds to at least one test hole.
4. The circuit board manufacturing method for preventing repeated drilling via back drilling according to claim 3, characterized in that, The test holes are set with M positions, and the back drill area is set with N positions, where M and N are both positive integers greater than or equal to 2. After providing the substrate, the method for manufacturing the circuit board to prevent repeated drilling via back drilling includes: The first hole is machined at the (N-1)th test hole position, and the depth of the first hole is less than or equal to the thickness of the substrate; The electroplated through hole in the M-1th back-drilled area is back-drilled; A second hole is machined at the N-1th test hole position. The second hole is coaxially arranged with the first hole. The diameter of the second hole is larger than that of the first hole. The second hole penetrates the substrate. The first hole is machined at the Nth test hole position, and the depth of the first hole is less than or equal to the thickness of the substrate; The electroplated through hole in the Mth back-drilled region is back-drilled; A second hole is machined at the Nth test hole position. The second hole is coaxially arranged with the first hole. The diameter of the second hole is larger than that of the first hole. The second hole penetrates the substrate.
5. The circuit board manufacturing method for preventing repeated drilling via back drilling according to claim 1, characterized in that, The diameter of the first hole is 0.3mm-1.0mm, and the diameter of the second hole is greater than 1.0mm.
6. The circuit board manufacturing method for preventing repeated drilling via back drilling according to claim 5, characterized in that, The diameter of the first hole is 0.5 mm, and the diameter of the second hole is 3.1 mm.
7. The circuit board manufacturing method for preventing repeated drilling via back drilling according to claim 1, characterized in that, A second hole is machined at the test hole using a second drill bit; after back drilling the electroplated through hole, an identification hole is machined on the substrate using the second drill bit.
8. The method for manufacturing a circuit board to prevent repeated drilling via back drilling according to any one of claims 1 to 7, characterized in that, The test hole is located on the process edge of the substrate.
Citation Information
Patent Citations
Drilling method for high-precision back drilling and circuit board
CN116261280A