Blind hole detection structure and blind hole detection method

Abstract

The present application discloses a blind hole detection structure and a blind hole detection method. The blind hole detection structure includes a substrate, a first detection point, a second detection point, and a hole deviation detection unit. The substrate is provided with a first blind hole, a second blind hole, and a third blind hole connected in series. The third blind hole is provided in plurality, and the first blind hole is electrically connected to the second blind hole via the third blind hole. The first detection point is electrically connected to the first blind hole via a resistor, the second detection point is electrically connected to the second blind hole, and the hole deviation detection unit is electrically connected to the first detection point and the second detection point. When detecting the quality of the blind hole provided on the substrate, the present application detects the resistance between the first detection point and the second detection point. If the resistance is greater than the resistance of the resistor, it is determined that an abnormality occurs in the bottom, shoulder, or sidewall of the blind hole. If the resistance is less than the resistance of the resistor, it is determined that the blind hole is deviated. The blind hole detection structure can simultaneously detect abnormalities in the hole deviation, bottom, shoulder, and side arm of the blind hole. It has a simple structure, occupies a small substrate area, and has high detection efficiency.

Description

Technical Field

[0001] The present application relates to the technical field of blind hole quality detection, and in particular to a blind hole detection structure and a blind hole detection method based on the blind hole detection structure. Background Art

[0002] During the production of blind vias on PCBs, quality issues often arise. For example, abnormalities or misalignment can lead to micro-breaks or micro-opens, while misalignment can cause short circuits, leading to market issues for batches of PCBs. Therefore, during PCB production, it is often necessary to inspect blind vias to improve PCB quality.

[0003] However, the existing blind hole detection structure for detecting blind holes in PCB boards has a complex structure, occupies a large substrate area, and has low detection efficiency. Summary of the Invention

[0004] An embodiment of the present application provides a blind hole detection structure, which occupies a small substrate area and has a simple structure.

[0005] In a specific embodiment, the blind hole detection structure includes a substrate, a first detection point, a second detection point, and a hole deviation detection unit. The substrate is provided with a first blind hole, a second blind hole, and a plurality of third blind holes connected in series. The first blind hole and the second blind hole are electrically connected to two ends of the third blind hole connected in series. The first detection point is electrically connected to the first blind hole via a resistor, the second detection point is electrically connected to the second blind hole, and the hole deviation detection unit is electrically connected to the first detection point and the second detection point. When inspecting the quality of the blind holes on the substrate, the resistance between the first detection point and the second detection point is detected, and then the resistance between the first detection point and the second detection point is compared with the resistance of the resistor to determine the quality of the blind holes on the substrate based on the comparison result. Furthermore, if the resistance between the first detection point and the second detection point is greater than the resistance of the resistor, it is determined that there is an abnormality in the bottom, shoulder, or sidewall of the blind hole. If the resistance between the first detection point and the second detection point is less than the resistance of the resistor, it is determined that the blind hole is misaligned. The blind hole detection structure can simultaneously detect abnormalities in the hole deviation, bottom, shoulder, and sidewall of the blind hole. It has a simple basic structure, occupies a small substrate area, and has high detection efficiency.

[0006] In a specific embodiment, a hole deviation detection unit includes a conductive detection hole and a conductive circuit layer. The conductive circuit layer is disposed within a substrate and has an insulating region within the conductive circuit layer. The conductive detection hole is formed in the substrate and located within the insulating region of the conductive circuit layer. A predetermined spacing of the insulating region is provided between the conductive detection hole and the conductive circuit layer, such that the conductive detection hole and the conductive circuit layer form two non-conductive networks. The conductive circuit layer is electrically connected to a first detection point, and the conductive detection hole is electrically connected to a second detection point. When the resistance between the first detection point and the second detection point is detected to be less than the resistance of the resistor, it indicates a short circuit between the conductive detection hole and the conductive circuit layer, indicating that the conductive detection hole is deflected, and thus that the blind hole is hole deviation. This blind hole hole deviation detection method is simple and efficient.

[0007] In one specific embodiment, the insulating region is annular, the conductive detection hole is a circular hole, and the circular hole and the annular insulating region are concentric circles. The predetermined spacing between the conductive detection hole and the conductive circuit layer is W, where W>0. In this embodiment, by setting the conductive detection hole and the insulating region as concentric circles, the spacing between the conductive detection hole and the conductive circuit layer is uniform in all directions, thereby achieving more accurate hole deviation detection results.

[0008] In a specific embodiment, the resistor is a chip resistor, and the resistance of the chip resistor is greater than or equal to 0.1Ω.

[0009] In one specific embodiment, the blind via detection structure further includes a pressurizing device for applying a clamping or pressing force to the region of the substrate where the blind via is located, or alternatively, to the entire substrate. This embodiment applies pressure to the substrate to induce impedance changes caused by unreliable blind via connections. This impedance change is then used to determine whether a PCB is defective, thereby improving substrate quality inspection.

[0010] In a specific embodiment, the pressurizing device includes a supporting portion and a pressurizing portion, which are used to clamp the area of ​​the substrate where the blind hole is provided, or the supporting portion and the pressurizing portion can also be used to clamp the entire substrate to stimulate unreliable blind hole connections of the substrate.

[0011] In a specific embodiment, the pressurizing device includes a pressurizing portion, which is used to press the region of the substrate where the blind hole is provided, so that the substrate is bent to stimulate unreliable blind hole connections of the substrate.

[0012] In a specific embodiment, the pressurizing portion includes pressurizing points, through which pressure is applied to the substrate, and the number of pressurizing points may be one, two, three or four.

[0013] In a specific embodiment, in order to facilitate the detection of the resistance between the first detection point and the second detection point, the first detection point and the second detection point are both exposed on the outer surface of the substrate, so that the probe can contact the first detection point and the second detection point, and then detect the resistance between the first detection point and the second detection point.

[0014] In a specific embodiment, the first detection point is connected to the first blind hole via a connecting wire, the connecting wire has a welding portion, the welding portion is exposed to the outer surface of the substrate, and the resistor is welded to the welding portion. In this embodiment, the welding portion is exposed to the outer surface of the substrate to facilitate welding of the resistor.

[0015] Correspondingly, the present application also provides a blind hole detection method for a blind hole detection structure, the blind hole detection structure comprising a substrate, a first detection point, a second detection point, and a hole deviation detection unit, wherein the substrate is provided with a first blind hole, a second blind hole, and a plurality of third blind holes connected in series, the first blind hole and the second blind hole being electrically connected to both ends of the third blind holes connected in series; the first detection point being electrically connected to the first blind hole via a resistor, the second detection point being electrically connected to the second blind hole, and the hole deviation detection unit being electrically connected to the first detection point and the second detection point; the blind hole detection method comprising:

[0016] Detecting a resistance value R1 between a first detection point and a second detection point in the substrate;

[0017] Determine the relationship between the resistance value R1 and the resistance value R0;

[0018] If the resistance values ​​R1 and R0 are equal, it is determined that each blind via in the substrate preliminarily meets the requirements. If the resistance value R1 is greater than the resistance value R0, it is determined that at least one blind via in the substrate has an abnormality in its bottom, shoulder, or sidewall. If the resistance value R1 is less than the resistance value R0, it is determined that each blind via in the substrate has an abnormality in hole deviation. This embodiment detects the resistance value R1 between the first detection point and the second detection point, and then compares the resistance value R1 with the resistance value R0 to determine whether the blind via has a deflected condition or whether the bottom, shoulder, or sidewall of the blind via has an abnormality. This detection method is simple, efficient, and accurate.

[0019] In a specific embodiment, after the step of determining that each blind hole in the substrate preliminarily meets the requirements, the blind hole detection method further includes:

[0020] Applying clamping force or pressing force to the substrate that initially meets the requirements;

[0021] Re-detecting the resistance R2 between the first detection point and the second detection point on the substrate;

[0022] Determine the relationship between resistance R2 and resistance R1;

[0023] If resistance R2 equals resistance R1, each blind via in the substrate is determined to meet requirements. If resistance R2 exceeds resistance R1, an abnormality is detected in the bottom, shoulder, or sidewall of at least one blind via in the substrate. This embodiment applies a clamping or pressing force to the substrate to induce impedance changes caused by unreliable blind via connections. This impedance change is used to determine whether the PCB is at risk, thereby improving substrate quality inspection.

[0024] Compared with the existing technology, the blind hole detection structure includes a substrate, a first detection point, a second detection point and a hole deviation detection unit. The substrate is provided with a first blind hole, a second blind hole and several third blind holes. The first blind hole, the second blind hole and the third blind hole are connected in series, and the first blind hole is electrically connected to the second blind hole through the third blind hole. The first detection point is electrically connected to the first blind hole through a resistor, and the second detection point is electrically connected to the second blind hole. The hole deviation detection unit is electrically connected to the first detection point and the second detection point. When detecting the quality of the blind hole provided on the substrate, the resistance between the first detection point and the second detection point is detected. If the resistance is greater than the resistance of the resistor, it is determined that there is an abnormality in the bottom, shoulder or side wall of the blind hole. If the resistance is less than the resistance of the resistor, it is determined that the blind hole is deviated. The blind hole detection structure can simultaneously detect abnormalities in the hole deviation, bottom, shoulder and side arm of the blind hole. It has a simple basic structure, occupies a small substrate area and has high detection efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a circuit diagram of the prior art for detecting abnormalities in blind holes in substrates.

[0026] Figure 2 This is a circuit diagram of the prior art for detecting blind hole deviation in a substrate.

[0027] Figure 3 A circuit diagram of a blind hole detection structure provided in an embodiment of the present application.

[0028] Figure 4 Schematic diagram of the internal structure of the blind hole detection structure provided in an embodiment of the present application.

[0029] Figure 5 A cross-sectional view of a blind hole detection structure provided in an embodiment of the present application.

[0030] Figure 6 A structural schematic diagram of a blind hole detection structure provided in an embodiment of the present application.

[0031] Figure 7 Schematic diagram of a blind hole detection structure with a pressurizing device provided in an embodiment of the present application.

[0032] Figure 8 Flowchart of a blind hole detection method provided in an embodiment of the present application.

[0033] Figure ID:

[0034] 1. Substrate; 2. Blind hole portion; 21. First blind hole; 22. Second blind hole; 23. Third blind hole; 3. Detection portion; 31. First detection point; 32. Second detection point; 4. Hole deviation detection portion; 41. Conductive detection hole; 42. Conductive circuit layer; 43. Insulation area; 5. Pressurizing device; 51. Support portion; 52. Pressurizing portion; 6. Probe; 100', Detection point; 200', Blind hole; 300', Hole deviation detection portion. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and advantages of this application more clearly understood, the present application is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0036] In the description of this application, unless otherwise expressly specified or limited, the terms "first" and "second" are used for descriptive purposes only and are not to be understood as indicating or implying relative importance; unless otherwise specified or explained, the term "plurality" refers to two or more; the terms "connected" and "fixed" should be understood in a broad sense. For example, "connected" can mean a fixed connection, a detachable connection, an integral connection, or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For those skilled in the art, the specific meanings of the above terms in this invention can be understood according to specific circumstances.

[0037] In the description of this specification, it should be understood that the directional words such as "upper" and "lower" described in the embodiments of the present application are described from the perspectives shown in the accompanying drawings and should not be understood as limiting the embodiments of the present application. In addition, in the context, it should be understood that when it is mentioned that an element is connected to another element "on" or "under", it can not only be directly connected to the other element "on" or "under", but also indirectly connected to the other element "on" or "under" through an intermediate element.

[0038] Reference Figure 1 and Figure 2 As shown, Figure 1 This is a circuit diagram of the prior art for detecting abnormalities in blind holes on substrates. Figure 2 The circuit diagram of the prior art for detecting the deviation of blind holes in substrates is shown in FIG. Figure 1 The resistance value between the two detection points 100' can be used to judge whether there are abnormalities in the bottom, shoulder and side wall of the blind hole. For the hole deviation detection of the blind hole 200' in the substrate, it can be detected by Figure 2The resistance value between the two detection points 100' is used to determine whether the blind via is misaligned (300' in the figure represents the misalignment detection unit for detecting misalignment). As can be seen, in the prior art, for quality inspection of blind vias in substrates, the hole bottom abnormality detection structure and the hole misalignment detection structure are separate, occupying a large substrate area and having low detection efficiency. Furthermore, after the substrate is processed into a PCBA (printed circuit board), cracking and misalignment of the blind vias cannot be properly intercepted, posing a risk of mass leakage into the market.

[0039] Reference Figure 3 and Figure 4 As shown, Figure 3 This is a partial structural diagram of the blind hole detection structure provided in an embodiment of the present application. Figure 4 Schematic diagram of the internal structure of a blind hole detection structure provided in an embodiment of the present application. The blind hole detection structure includes a substrate 1, a blind hole portion 2, a detection portion 3, a hole deviation detection portion 4, and a resistor R. The blind hole portion 2, the detection portion 3, and the hole deviation detection portion 4 are respectively arranged on the substrate 1, and the blind hole portion 2 is electrically connected to the detection portion 3 after being connected in series with the resistor R, and the hole deviation detection portion 4 is directly electrically connected to the detection portion 3. When detecting the quality of each blind hole in the blind hole portion 2, the resistance value of the detection portion 3 is tested by a probe, and then the resistance value is compared with the resistance value of the resistor R. The quality of each blind hole in the blind hole portion 2 can be determined based on the comparison result, for example, whether there is any blind hole abnormality or blind hole deviation.

[0040] Specifically, the detection unit 3 includes a first detection point 31 and a second detection point 32. The blind hole portion 2 includes a first blind hole 21, a second blind hole 22, and a third blind hole 23. There are multiple third blind holes 23. The first blind hole 21, the second blind hole 22, and the multiple third blind holes 23 are connected in series, and the first blind hole 21 is electrically connected to the second blind hole 22 via the third blind hole 23. The first detection point 31 is electrically connected to the first blind hole 21 via a resistor R, and the second detection point 32 is electrically connected to the second blind hole 22. The hole deviation detection unit 4 is electrically connected to the first detection point 31 and the second detection point 32.

[0041] When inspecting the quality of blind vias on a PCB, it is only necessary to detect the resistance between the first inspection point 31 and the second inspection point 32, and then compare the resistance between the first inspection point 31 and the second inspection point 32 with the resistance of the resistor R. If the resistance between the first inspection point 31 and the second inspection point 32 is greater than the resistance of the resistor R, it is determined that an abnormality has occurred in the bottom, shoulder, or sidewall of the blind via in the PCB, such as an open circuit. If the resistance between the first inspection point 31 and the second inspection point 32 is less than the resistance of the resistor R, it is determined that the blind via in the PCB is misaligned, such as a short circuit. This prevents defective PCBs from being released to the market, thereby achieving a simplified interception of PCBs with blind via quality defects. The blind via inspection structure is simple, occupies a small area of ​​the substrate 1, and has high inspection efficiency and low cost.

[0042] Also refer to Figure 4 and Figure 5 As shown, Figure 5 A cross-sectional view of a blind hole detection structure provided in an embodiment of the present application. The hole deviation detection portion 4 includes a conductive detection hole 41 and a conductive circuit layer 42, and the conductive detection hole 41 and the conductive circuit layer 42 are respectively arranged on the substrate 1. An insulating area 43 is provided in the conductive circuit layer 42, and the conductive detection hole 41 is opened in the insulating area 43, and there is an insulating area 43 with a preset distance between the conductive detection hole 41 and the conductive circuit layer 42, so that the conductive detection hole 41 and the conductive circuit layer 42 are two non-conductive networks. The conductive circuit layer 42 is electrically connected to the first detection point 31 via a first lead, and the conductive detection hole 41 is electrically connected to the second detection point 32 via a second lead. Among them, the conductive detection hole 41 is formed by drilling a suitable hole on the substrate 1 as required, and then copper plating.

[0043] In this embodiment, the first lead is disposed inside the substrate 1, and the second lead is disposed at the bottom of the substrate 1. It is understood that in other embodiments, the first lead and the second lead may also be disposed at other locations on the substrate 1, for example, at the top of the substrate 1, as long as the first lead and the second lead are not electrically conductive.

[0044] If an abnormality occurs in the bottom, shoulder, or sidewall of any blind via, an open circuit will occur, causing the resistance between the first detection point 31 and the second detection point 32 to be greater than the resistance of the resistor R. Therefore, if the resistance between the first detection point 31 and the second detection point 32 is greater than the resistance of the resistor R, it is determined that an abnormality occurs in the bottom, shoulder, or sidewall of the blind via in the PCB board. If the conductive detection hole 41 is punched off-center, a short circuit may occur between the conductive detection hole 41 and the conductive circuit layer 42. That is, two non-conductive networks form a network, so that the resistance between the first detection point 31 and the second detection point 32 is less than the resistance of the resistor R. Therefore, if it is detected that the resistance between the first detection point 31 and the second detection point 32 is less than the resistance of the resistor R, it is determined that the conductive detection hole 41 is skewed. Since the conductive detection hole 41 and the blind holes are punched together by the same punching device and according to the same punching standard, the hole diameter, hole depth, etc. of the conductive detection hole 41 and the blind holes are basically the same. That is, if it is determined that the conductive detection hole 41 is offset, it can be indirectly determined that the blind holes are also offset.

[0045] In order to improve the accuracy of blind hole deviation detection, the insulating area 43 is annular, the conductive detection hole 41 is a circular hole, and the circular hole is concentric with the above-mentioned ring. The preset spacing between the conductive detection hole 41 and the conductive circuit layer 42 is W, W>0. In this way, no matter in which direction the conductive detection hole 41 deviates, it may cause a short circuit between the conductive detection hole 41 and the conductive circuit layer 42, thereby improving the accuracy of blind hole deviation detection, and the specific value of W can be set according to actual needs to avoid over-interception.

[0046] In order to further improve the accuracy of blind hole quality detection, the resistor R is a chip resistor, and the resistance of the chip resistor is greater than or equal to 0.1Ω. Of course, the resistance of the resistor R can be set to be larger, for example, it can be 500Ω, 1K, 2K, etc., because if the resistance of the resistor R is too small, it is difficult to distinguish between the short circuit and non-short circuit states in the electrical connection structure, which may affect the blind hole quality detection result.

[0047] Reference Figure 6 As shown, Figure 6 This is a schematic diagram of the blind via detection structure provided in an embodiment of the present application. A first detection point 31 is connected to a first blind via 21 via a connecting wire. The connecting wire has a soldering portion exposed to the outer surface of the substrate 1. A resistor R is soldered to the soldering portion, and both the first detection point 31 and the second detection point 32 are exposed to the outer surface of the substrate 1. This embodiment exposes the soldering portion, the first detection point 31, and the second detection point 32 to the outer surface of the substrate 1, facilitating resistor soldering and detection, thereby improving detection efficiency.

[0048] Since the present application is provided with a resistor and judges the abnormality of the blind hole by comparing the resistance value between the two detection points with the resistance value of the resistor, it can also detect some unreliable connection states of the blind hole. Because the present application requires attaching a device (resistor) on the substrate 1, and then re-melting it at a high temperature to solder the resistor to the substrate. However, after the substrate 1 is re-melted at a high temperature, some unreliable connections of the blind hole may be completely open. At this time, if the blind hole is subjected to quality inspection again, the PCB board with abnormal blind holes can be further detected, and the abnormal PCBA board can be intercepted.

[0049] Reference Figure 7 As shown, Figure 7 Schematic diagram of a blind hole detection structure with a pressurizing device 5 provided in an embodiment of the present application. The blind hole detection structure also includes a pressurizing device 5, which is used to apply a clamping force or pressing force to at least the region of the substrate 1 where the blind hole is provided. By applying pressure to the substrate 1, the impedance change caused by unreliable blind hole connections is stimulated. The impedance change is used to determine whether the material is a risk material, thereby increasing the interception effect of micro-defects on the substrate 1.

[0050] Specifically, when no clamping force or pressing force is applied to the substrate 1, the resistance R1 between the first detection point 31 and the second detection point 32 is detected by the probe 6. After the clamping force or pressing force is applied to the substrate 1, the resistance R2 between the first detection point 31 and the second detection point 32 is detected by the probe 6. Then, based on the magnitude relationship between the resistance R1 and the resistance R2, it is determined whether there is an unreliable blind hole connection on the PCB board, that is, whether there is a risky PCB board.

[0051] For example, since the substrate is formed by laminating multiple layers, after applying a clamping force or a pressing force to the substrate 1, some unreliable blind hole connections may change their states. For example, the original connection state at the bottom of the hole may change to an open circuit state. If the resistance value between the first detection point 31 and the second detection point 32 is detected as R2 at this time, and before applying the clamping force or pressing force to the substrate 1, the resistance value between the first detection point 31 and the second detection point 32 is detected as R1, then R1 < R2 or R1 = R2 should hold. In other words, if R1 < R2, it is determined that there are unreliable blind hole connections in the corresponding PCB board, that is, this PCB board is a risky PCB board. If the resistance value R1 is basically equal to the resistance value R2, it is determined that there are no unreliable blind hole connections in the corresponding PCB board.

[0052] In this embodiment, the pressing device 5 includes a support portion 51 and a pressing portion 52. The support portion 51 and the pressing portion 52 are used to at least clamp the area of the substrate 1 provided with blind holes. When detecting the blind hole quality of the PCB board, first detect the resistance value between the first detection point 31 and the second detection point 32. Then, after clamping the area of the substrate 1 provided with blind holes by the support portion 51 and the pressing portion, detect the resistance value between the first detection point 31 and the second detection point 32 again. Then, based on the change in the measured resistance values twice, further intercept risky PCB boards.

[0053] It can be understood that in other embodiments, the pressing device 5 may also only include a pressing portion, and this pressing portion is used to at least press the area of the substrate 1 provided with blind holes to make the substrate 1 in a bent state. When detecting the blind hole quality of the PCB board, first detect the resistance value between the first detection point 31 and the second detection point 32. Then, after pressing the area of the substrate 1 provided with blind holes (to make the substrate 1 in a bent state) by the pressing portion, detect the resistance value between the first detection point 31 and the second detection point 32 again. Then, based on the change in the measured resistance values twice, further intercept risky PCB boards.

[0054] Of course, the pressing force applied to the substrate 1 cannot be too large to prevent the substrate 1 from being broken due to excessive bending. In specific implementation, an appropriate pressing force can be selected according to the thickness of the substrate 1, such as a dozen Newtons.

[0055] Furthermore, the pressing portion includes pressing points, and pressure is applied to the substrate 1 through the pressing points. The number of pressing points can be one, two, three, four, etc., which is not limited here.

[0056] Based on the above embodiments, the embodiments of the present application also disclose a blind hole detection method, which is applied to the blind hole detection structure of the above embodiments. Refer to Figure 8 As shown in the figure, the figure is a flowchart of a blind hole detection method provided by an embodiment of the present application. This blind hole detection method includes the steps:

[0057] S11 , detecting a resistance R1 between a first detection point and a second detection point on the substrate.

[0058] Specifically, the resistance R1 between the first detection point and the second detection point can be measured by a multimeter.

[0059] S12. Determine the relationship between the resistance value R1 and the resistance value R0 of the resistor R; if the resistance value R1 is equal to the resistance value R0, proceed to step S13; if the resistance value R1 is greater than the resistance value R0, proceed to step S18; if the resistance value R1 is less than the resistance value R0, proceed to step S19.

[0060] S13. Determine whether each blind hole in the substrate initially meets the requirements.

[0061] S14. Applying a clamping force or a pressing force to the substrate that preliminarily meets the requirements.

[0062] Specifically, the substrates that preliminarily meet the requirements may include substrates with unreliable blind hole connections. Therefore, it is necessary to apply a clamping force or a pressing force to the substrates that preliminarily meet the requirements to further eliminate them and improve the accuracy of detection.

[0063] S15 , again detecting the resistance R2 between the first detection point and the second detection point on the substrate.

[0064] Specifically, a clamping or pressing force is applied to a substrate that initially meets the requirements, causing it to bend. The clamping or pressing force is then removed, and the resistance R2 between the first and second detection points on the substrate is measured. Because substrates are laminated together from multiple layers, some unreliable blind via connections may exist. Applying a clamping or pressing force to the substrate can cause these unreliable connections in the blind vias to become open circuits. By comparing the impedance change between the two detection points before and after the pressure is applied, PCBs with abnormal blind vias can be further excluded.

[0065] S16, determine the relationship between the resistance value R2 and the resistance value R1. If the resistance value R2 is equal to the resistance value R1, proceed to step S17. If the resistance value R2 is greater than the resistance value R1, proceed to step S18.

[0066] S17. Determine whether each blind hole in the substrate meets the requirements.

[0067] S18. Determine whether an abnormality occurs in the bottom, shoulder, or sidewall of at least one blind hole in the substrate.

[0068] S19, determining whether each blind hole in the substrate has a hole deviation anomaly.

[0069] The present application only needs to detect the resistance value between the first detection point 31 and the second detection point 32 in the substrate 1, and then determine whether each blind hole in the substrate preliminarily meets the requirements based on the relationship between the resistance value and the resistance value of the resistor. PCB boards with abnormal blind holes are intercepted, and then by applying a clamping force or pressing force to the substrates that preliminarily meet the requirements, PCB boards with abnormal blind holes can be further intercepted. The detection method is simple, efficient, and accurate.

[0070] The above-mentioned blind hole quality inspection is not limited to application in PCB production process, SMT (surface mount technology) process, equipment testing process, etc. The above-mentioned blind hole detection structure is applied to high-density interconnection board (English full name: High Density Interconnect, abbreviated as: HDI), which can be used in mobile phones, tablets, PCs (computers), etc.

[0071] The above description is merely a preferred embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A blind hole detection structure, which is applied to a high-density interconnection board, characterized in that: The blind hole detection structure comprises: A substrate is provided with a first blind hole, a second blind hole, and a third blind hole connected in series, wherein a plurality of the third blind holes are provided, and the first blind hole is electrically connected to the second blind hole via the third blind hole; a first detection point, the first detection point being electrically connected to the first blind hole via a resistor; a second detection point, the second detection point being electrically connected to the second blind hole; a hole deviation detection unit, the hole deviation detection unit being electrically connected to the first detection point and the second detection point; The hole deviation detection part includes a conductive detection hole and a conductive circuit layer, and the conductive detection hole and the conductive circuit layer are respectively arranged on the substrate; An insulating area is provided in the conductive circuit layer, the conductive detection hole is opened in the insulating area, and there is an insulating area with a preset distance between the conductive detection hole and the conductive circuit layer. The conductive circuit layer is electrically connected to the first detection point, and the conductive detection hole is electrically connected to the second detection point.

2. The blind hole detection structure according to claim 1, characterized in that: The insulating area is annular, the conductive detection hole is a circular hole, and the circular hole and the annular are concentric circles. The preset distance between the conductive detection hole and the conductive circuit layer is W, and W>0.

3. The blind hole detection structure according to claim 1, characterized in that: The resistor is a chip resistor, and the resistance of the chip resistor is greater than or equal to 0.1Ω.

4. The blind hole detection structure according to claim 1, characterized in that: The blind hole detection structure further includes a pressurizing device, which is used to apply a clamping force or a pressing force to at least the region of the substrate where the blind hole is located.

5. The blind hole detection structure according to claim 4, characterized in that: The pressurizing device includes a supporting portion and a pressurizing portion, and the supporting portion and the pressurizing portion are used to clamp at least the region of the substrate where the blind hole is provided.

6. The blind hole detection structure according to claim 4, characterized in that: The pressurizing device includes a pressurizing portion, and the pressurizing portion is used to press at least the region of the substrate where the blind hole is provided, so that the substrate is in a bent state.

7. The blind hole detection structure according to claim 6, characterized in that: The pressurizing portion includes pressurizing points through which pressure is applied to the substrate. The number of pressurizing points may be one, two, three, or four.

8. The blind hole detection structure according to any one of claims 1 to 7, characterized in that: The first inspection point and the second inspection point are both exposed on the outer surface of the substrate.

9. The blind hole detection structure according to any one of claims 1 to 7, characterized in that: The first detection point is connected to the first blind hole via a connecting wire. The connecting wire is provided with a welding portion. The welding portion is exposed on the outer surface of the substrate. The resistor is welded to the welding portion.

10. A blind hole detection method for a blind hole detection structure, characterized in that: The blind hole detection structure includes a substrate, a first detection point, a second detection point, and a hole deviation detection unit. The substrate is provided with a first blind hole, a second blind hole, and a third blind hole connected in series. The third blind hole is provided in plurality, and the first blind hole is electrically connected to the second blind hole via the third blind hole. The first detection point is electrically connected to the first blind hole via a resistor, and the second detection point is electrically connected to the second blind hole. The hole deviation detection unit is electrically connected to the first detection point and the second detection point. The blind hole detection method includes: Detecting a resistance value R1 between a first detection point and a second detection point in the substrate; Determine the magnitude relationship between the resistance value R1 and the resistance value R0; If the resistance value R1 is equal to the resistance value R0, it is determined that each blind hole in the substrate preliminarily meets the requirements. If the resistance value R1 is greater than the resistance value R0, it is determined that an abnormality occurs in the bottom, shoulder or sidewall of at least one blind hole in the substrate. If the resistance value R1 is less than the resistance value R0, it is determined that each blind hole in the substrate has a hole deviation abnormality.

11. The blind hole detection method according to claim 10, characterized in that: After the step of determining that each blind hole in the substrate preliminarily meets the requirements, the blind hole detection method further includes: Applying a clamping force or a pressing force to the substrate that preliminarily meets the requirements; Re-detecting the resistance R2 between the first detection point and the second detection point on the substrate; Determine the magnitude relationship between the resistance value R2 and the resistance value R1; If the resistance value R2 is equal to the resistance value R1, it is determined that each blind hole in the substrate meets the requirements. If the resistance value R2 is greater than the resistance value R1, it is determined that an abnormality occurs in the bottom, shoulder or sidewall of at least one blind hole in the substrate.

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