Circuit board and back drilling test module thereof

Abstract

The utility model discloses a circuit board and a back drilling test module thereof, the back drilling test module of the circuit board comprises a test hole group, the test hole group comprises a first test hole setting area and a second test hole setting area, and the first test hole setting area and the second test hole setting area are arranged on the same back drilling technology as back drilling holes in the circuit board. A first test hole and a second test hole are arranged. The test module further comprises a back drilling hole pulling-out layer, a back drilling hole final drilling layer, a first conductive layer and a second conductive layer, the back drilling hole penetrates through all inner layers from the back drilling hole pulling-out layer to the back drilling hole final drilling layer, and the first conductive layer is located between the back drilling hole pulling-out layer and the back drilling hole final drilling layer. The second conductive layer is located on the side, away from the back drilling pull-out layer, of the back drilling final drilling layer, and the first conductive layer and the second conductive layer respectively comprise a first test signal line and a second test signal line. According to the technical scheme of the utility model, a simple structure can be adopted, and the drilling depth and deviation of the back drill can be accurately and efficiently tested at the same time.

Description

Technical Field

[0001] The embodiments of the utility model relate to the technical field of PCBs, and in particular to a circuit board and a backdrill test module thereof. Background Art

[0002] In the prior art, printed circuit boards (PCBs) are generally composed of multiple layers of boards. To achieve electrical connectivity between the multiple layers, holes are usually opened in the PCBs and a layer of conductive metal such as copper is electroplated on the inner wall of the holes, thereby achieving electrical conduction between the multiple layers.

[0003] In the production of multilayer boards, it is often necessary to divide the board into sections A and B along the stacking direction. The boards within section A are electrically connected, while those within section B do not. During PCB fabrication, to reduce electrical losses and ineffective transmission in section B, through-holes are typically created on the PCB board, penetrating both sections A and B. Copper is then plated on the inner walls of these through-holes, and back-drilling is then used to remove the ineffective copper from section B. During back-drilling, to prevent damage to the copper plating in section A caused by excessively deep back-drilling, a short copper stub is typically left at the bottom of section B.

[0004] As wiring density increases, the distance between backdrilled holes and inner-layer pattern traces becomes increasingly close. Backdrilled holes that reach inner-layer pattern traces but don't completely penetrate them can be difficult to detect through normal electrical testing, posing a serious risk to the long-term reliability of the product. Therefore, monitoring backdrill depth and deviation is a major technical challenge in ensuring circuit board quality. Existing methods include slicing to confirm detection and conducting open-circuit and short-circuit tests using electrical testers. However, slicing testing is inefficient, and electrical testers must test for backdrilling errors in separate modules, such as shallowness, depth, and deviation. This complicates the structure of the backdrilling test module, hindering its application in a wider range of fields. Utility Model Content

[0005] The utility model provides a circuit board and a backdrill test module thereof, which adopts simple results to test the backdrilling depth and backdrilling deviation at the same time, thereby improving the backdrilling test efficiency and test accuracy of the circuit board.

[0006] The first aspect of the present invention provides a backdrill test module for a circuit board, comprising: at least one test hole group; each of the test hole groups comprises at least one first test hole setting area and at least one second test hole setting area;

[0007] The first test hole setting area is used to set the first test hole under the same back drilling process as the back drilling process in the circuit board;

[0008] The second test hole setting area is used to set the second test hole under the same back drilling process as the back drilling process in the circuit board;

[0009] The backdrill test module of the circuit board at least includes a backdrilling start layer, a backdrilling end layer, a first conductive layer, and a second conductive layer; the backdrilled hole penetrates each inner layer from the backdrilling start layer to the backdrilling end layer;

[0010] The first conductive layer is located between the back-drilled hole starting layer and the back-drilled hole finishing layer; the first conductive layer includes at least one first test signal line corresponding to at least one group of the test hole groups; the first test signal line includes a first test portion and a second test portion;

[0011] The second conductive layer is located on a side of the backdrilled hole final drilling layer away from the backdrilled hole starting drilling layer; the second conductive layer includes at least one second test signal line corresponding to at least one group of the test hole groups;

[0012] In a direction perpendicular to the plane where the first conductive layer is located, the first test hole setting area overlaps with the first test portion and the second test signal line, and the second test hole setting area does not overlap with either the first test portion or the second test signal line; the second test portion at least partially surrounds the second test hole setting area.

[0013] Optionally, the backdrill test module for the circuit board further includes: a first test structure, a second test structure and a third test structure;

[0014] The first test structure is electrically connected to the first end of the first test section, the second test structure is electrically connected to the second end of the first test section and the first end of the second test section, and the third test structure is electrically connected to the second end of the second test section.

[0015] Optionally, the backdrill test module for the circuit board further includes: a fourth test structure and a fifth test structure;

[0016] The second test signal line is electrically connected between the fourth test structure and the fifth test structure.

[0017] Optionally, the first testing portion includes a first connecting segment, a second connecting segment, and at least one branch segment corresponding to at least one first testing hole setting area;

[0018] Both ends of the branch segment are connected to the first connecting segment and the second connecting segment respectively.

[0019] Optionally, the second testing portion includes a plurality of third connecting segments and an open annular segment connected between two adjacent third connecting segments;

[0020] The open annular segment surrounds the second testing hole setting area.

[0021] Optionally, when the backdrill test module of the circuit board includes a plurality of test hole groups, the line widths of the open annular segments around the second test hole setting areas of at least two of the test hole groups are different.

[0022] Optionally, when the second testing portion includes a plurality of open annular segments, the opening directions of any two adjacent open annular segments are opposite.

[0023] Optionally, in the backdrill test module of the circuit board, in a direction parallel to the plane where the first conductive layer is located, the size of the second test hole setting area is equal to the inner ring size of the open ring segment.

[0024] Optionally, the second test signal line includes a fourth connecting segment, a fifth connecting segment, and a sixth connecting segment connected between the fourth connecting segment and the fifth connecting segment;

[0025] In a direction perpendicular to the plane where the first conductive layer is located, each first test hole arrangement area of ​​the same test hole group overlaps with the sixth connecting segment.

[0026] A second aspect of the present invention provides a circuit board, comprising: a circuit arrangement area and a peripheral area at least partially surrounding the circuit arrangement area;

[0027] The circuit arrangement area is provided with at least one back-drilled hole;

[0028] The peripheral area is provided with the circuit board backdrill test module as described above.

[0029] The technical solution provided by the utility model is to set at least one test hole group, and each test hole group includes at least one first test hole setting area and at least one second test hole setting area, and the first test hole setting area and the second test hole setting area are respectively set with the first test hole and the second test hole setting area under the same back drilling process as the back drilling hole in the circuit board, so that the penetration layer and position offset of the first test hole and the second test hole can be consistent with the back drilling hole, so that the penetration module and position offset of the back drilling hole can be determined by testing the penetration layer and position offset of the first test hole and the second test hole; at the same time, by setting the first test signal line in the second conductive layer between the back drilling hole starting layer and the back drilling hole final drilling layer, and the second conductive layer on the back drilling hole final drilling layer away from the back drilling hole starting layer A first test signal line is set in the middle, and by making the first test hole setting area overlap with the first test portion and the second test signal line of the first test signal line, and the second test portion of the first test signal line is at least partially set around the second test hole setting area, and by determining the on-off state of the first test portion and the on-off state of the second test signal line, the drilling depth of the first test hole set in the first test hole setting area can be determined, so that the drilling depth of the back drilled hole can be determined based on the drilling depth, and whether the back drilled hole is drilled too deep or too shallow can be detected. Moreover, by detecting the on-off state of the second test portion, it can be determined whether the position of the second test hole set in the second test hole setting area is offset, so that according to the position offset of the second test hole, whether the position of the back drilled hole is aligned can be detected. The utility model can simultaneously detect the drilling depth and alignment of the back drilled hole through a simple structure, and can reduce the size of the structure of the back drilled hole test module, which is conducive to improving test efficiency, simplifying test methods, and reducing test costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0031] Figure 1 This is a schematic top view of a backdrill test module for a circuit board provided by an embodiment of the present utility model;

[0032] Figure 2 This is a schematic cross-sectional view of a backdrill test module for a circuit board provided by an embodiment of the present utility model;

[0033] Figure 3 This is a schematic cross-sectional view of another circuit board backdrill test module provided by an embodiment of the present utility model;

[0034] Figure 4 This is a schematic cross-sectional view of another circuit board backdrill test module provided by an embodiment of the present utility model;

[0035] Figure 5 This is a schematic top view of another circuit board backdrill test module provided by an embodiment of the present utility model;

[0036] Figure 6 This is a schematic top view of another circuit board backdrill test module provided by an embodiment of the present utility model;

[0037] Figure 7 This is a schematic top view of another circuit board backdrill test module provided by an embodiment of the present utility model;

[0038] Figure 8 This is a schematic top view of another circuit board backdrill test module provided by an embodiment of the present utility model;

[0039] Figure 9 This is a schematic top view of another circuit board backdrill test module provided by an embodiment of the present utility model;

[0040] Figure 10 This is a structural diagram of a circuit board provided by an embodiment of the utility model. DETAILED DESCRIPTION

[0041] In order to help those skilled in the art better understand the present invention, the following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0042] It should be noted that the terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that the numbers used in this way can be interchanged where appropriate, so that the embodiments of the present invention described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0043] Figure 1 This is a schematic top view of a backdrill test module for a circuit board provided by an embodiment of the present utility model. Figure 2 This is a schematic cross-sectional view of a backdrill test module for a circuit board provided by an embodiment of the present invention. Figure 1 and Figure 2 The backdrilling test module for the circuit board includes at least one test hole group, each test hole group includes at least one first test hole setting area 1 and at least one second test hole setting area 2. The first test hole setting area 1 is used to set the first test hole 101 under the same backdrilling process as the backdrilling holes in the circuit board, and the second test hole setting area 2 is used to set the second test hole 201 under the same backdrilling process as the backdrilling holes in the circuit board.

[0044] It is understood that in the embodiments of the present invention, the backdrill test module is provided with at least one test hole group, that is, the backdrill test module can be provided with one or more test hole groups, and the specific configuration can be based on actual needs, and the embodiments of the present invention are not specifically limited to this. For ease of description, unless otherwise specified, the embodiments of the present invention are illustrative of the backdrill test module including one test hole group.

[0045] Accordingly, each test hole group may include one or more first test hole setting areas 1, and one or more second test hole setting areas 2, which can be specifically designed according to actual needs, and the embodiment of the present utility model does not specifically limit this. Among them, since the first test hole setting area 1 is used to set the first test hole 101 under the same back drilling process as the back drilling hole in the circuit board, the number of the first test hole setting areas 1 can be designed according to the number of back drilling holes required to be set in the circuit board, and the situation of the back drilling holes penetrating the layer; similarly, since the second test hole setting area 2 is used to set the second test hole 102 in the circuit board under the same back drilling process as the back drilling hole in the circuit board, the number of the second test hole setting areas 2 can also be designed according to the number of back drilling holes required to be set in the circuit board, and the situation of the back drilling holes penetrating the layer.

[0046] It can also be understood that the first test hole 101 set in the first test hole setting area 1 and the second test hole 102 placed in the second test hole setting area 2 can be formed using the same back drilling process as the back drilled hole in the circuit board, that is, the process parameters for setting the first test hole 101 and the second test hole 102 can be consistent with the process parameters of the back drilled hole in the circuit board, so that the depth, width, alignment coordinate offset, etc. of the back drilled hole and the first test hole 101 and the second test hole 102 are consistent, so that after determining the drilling depth and alignment offset of the first test hole 101, the drilling depth and alignment offset of the back drilled hole can be determined accordingly. In this way, by making the first test hole 101 and the second test hole 201 adopt the same process setting as the back drilled hole in the circuit board, it can ensure that the depth and accuracy of the test hole and the back drilled hole are better matched, thereby improving the accuracy of the back drill test.

[0047] Continue to refer Figure 1 As shown, the backdrill test module of the circuit board at least includes a backdrilling start layer 3 and a backdrilling end layer 4 , and the backdrilled holes penetrate through each inner layer from the backdrilling start layer 3 to the backdrilling end layer 4 .

[0048] Among them, the back drilling starting layer 3 can be specifically understood as the first inner layer that the drill needs to drill through when setting the back drilling hole of the circuit board, and the back drilling final drilling layer 4 can be specifically understood as the last layer that the drill needs to drill through when setting the back drilling hole of the circuit board, that is, the back drilling starting layer 3 is used as the theoretical drilling starting layer when setting the back drilling hole, and the back drilling final drilling layer 4 is used as the theoretical drilling ending layer when setting the back drilling hole. The back drilling hole should pass through the back drilling starting layer 3, the back drilling final drilling layer 4, and the inner layers located between the back drilling starting layer 3 and the back drilling final drilling layer 4; accordingly, when the first test hole 101 and the second test hole 102 are set using the same back drilling process as the back drilling hole, the first test hole 101 and the second test hole 102 should also pass through the back drilling starting layer 3, the back drilling final drilling layer 4, and the inner layers located between the back drilling starting layer 3 and the back drilling final drilling layer 4.

[0049] Continue to refer Figure 1As shown, the backdrilling test module of the circuit board also includes at least a first conductive layer 5 and a second conductive layer 6. The first conductive layer 5 is located between the backdrilling start layer 3 and the backdrilling end layer 4. The first conductive layer 5 includes at least one first test signal line 110 corresponding to at least one group of test hole groups. The first test signal line includes a first test portion 11 and a second test portion 12. The second conductive layer 6 is located on a side of the backdrilling end layer 4 away from the backdrilling start layer 3. The second conductive layer 6 includes at least one second test signal line 210 corresponding to at least one group of test hole groups. In a direction Z perpendicular to the plane where the first conductive layer 5 is located, the first test hole setting area 1 overlaps with the first test portion 11 and the second test signal line 210, the second test hole setting area 2 does not overlap with either the first test portion 11 or the second test signal line 210, and the second test portion 12 at least partially surrounds the second test hole setting area 2.

[0050] It is understood that at least one test hole group corresponds to at least one first test signal line 110, and at least one test hole group corresponds to at least one second test signal line 210, so that the number of first test signal lines 110 and second test signal lines 210 can be the same as or different from the number of test hole groups, and can be specifically designed according to actual needs. The embodiment of the present utility model takes the example that the number of first test signal lines 110 and second test signal lines 210 is the same as the number of test hole groups, that is, the first test signal lines 110 and second test signal lines 210 are both arranged in a one-to-one correspondence with the test hole groups, to exemplify the technical solution of the embodiment of the present utility model.

[0051] Among them, the first conductive layer 5 is located between the back-drilling starting layer 3 and the back-drilling finishing layer 4, that is, when setting the first test hole 101 and the second test hole 102, theoretically the first test hole 101 and the second test hole 102 should pass through the first conductive layer 5; the second conductive layer 6 is located on the side of the back-drilling finishing layer 4 away from the back-drilling starting layer 3, that is, when setting the first test hole 101 and the second test hole 102, theoretically the first test hole 101 and the second test hole 102 should not pass through the second conductive layer 6.

[0052] Specifically, since the first test hole arrangement area 1 overlaps with the first test portion 11 of the first test signal line 110 and the second test signal line 210 in a direction perpendicular to the plane where the first conductive layer 5 is located, the first test hole 101 in the first test hole arrangement area 1 can overlap with the first test portion 11 and the second test signal line 210 in a direction perpendicular to the plane where the first conductive layer 5 is located. When the first test hole 101 is not drilled too deep or too shallow, the position where the first test portion 11 overlaps with the first test hole 101 is disconnected, while the position where the second test signal line 210 overlaps with the first test hole 101 remains conductive. When the first test hole 101 is drilled too deep, the first test hole 101 may penetrate the first conductive layer 5 and the second conductive layer 6 at the same time, so that the position where the first test part 11 overlaps with the first test hole 101, and the position where the second test signal line 210 overlaps with the first test hole 101 are both in a disconnected state; when the first test hole 101 is drilled too shallow, the first test hole 101 may not penetrate the first conductive layer 5 and the second conductive layer 6, so that the position where the first test part 11 overlaps with the first test hole 101, and the position where the second test signal line 210 overlaps with the first test hole 101 are both in a conductive state. In this way, by testing the continuity status of the first test part 11 and the first test signal line 210 at the position overlapping with the first test hole setting area 1, it is possible to determine whether the first test hole 101 set in the first test hole setting area 1 has the problem of being drilled too deep or too shallow, so as to correspondingly determine whether the back-drilled hole in the circuit board formed under the same back-drilling process as the first test hole 101 has the problem of being too deep or too shallow. Therefore, there is no need to set the first test hole 101 separately for detecting whether the back-drilled hole is too deep or too shallow, which can simplify the structure of the back-drilling test module and the testing method.

[0053] Since the second test hole setting area 2 does not overlap with the first test part 11 and the second test signal line 210 in the direction perpendicular to the plane where the first conductive layer 5 is located, and the second test part 12 at least partially surrounds the second test hole setting area 2, the second test hole 102 set in the second test hole setting area 2 should not overlap with the second test part 11 and the second test signal line 120, that is, when the setting position of the second test hole 102 does not shift, the second test hole 102 will not damage the second test part 12 around it, so that each position of the second test part 12 can maintain a conductive state; when the setting position of the second test hole 102 shifts, the second test hole 102 will damage the second test part 12 around it, so that the second test part 12 is in a disconnected state. In this way, by testing the on-off status of the second test part 12, it is possible to determine whether the setting position of the second test hole 102 is aligned with the second test hole setting area 2, that is, whether the second test hole 102 has a position offset problem, so as to correspondingly determine whether the back-drilled hole in the circuit board formed under the same back-drilling process as the second test hole 102 has a position offset problem, thereby using different test parts of the same first test signal line 110 to detect the position offset and drilling depth of the back-drilled hole respectively, without having to set different test signal lines for detecting the drilling depth and position offset of the back-drilled hole, which can simplify the structure of the back-drilling test module and simplify the testing method.

[0054] In an exemplary embodiment, Figure 3 This is a schematic cross-sectional view of another circuit board backdrill test module provided by the present invention, with reference to FIG. Figure 1 and Figure 3 As shown, when the first test hole 101 set in the first test hole setting area only penetrates the back-drilled hole starting layer 3 and part of the inner layer between the back-drilled hole starting layer 3 and the first conductive layer 5, the first test portion 11 of the first test signal line 110 set in the first conductive layer 5 and the second test signal line 120 set in the second conductive layer 6 are both in a conductive state; at this time, power signals are respectively introduced into the first test portion 11 and the second test signal line 120 on both sides of the first test hole 101, and the first test portion 11 and the second test signal line 120 on both sides of the first test hole 101 are both in a short-circuit state, thereby determining that the first test hole 101 does not penetrate the first conductive layer 5, and the first test hole 101 has a shallow drilling problem, thereby determining that the back-drilled hole formed in the same back-drilling process as the first test hole 101 has a shallow drilling problem.

[0055] In another exemplary embodiment, Figure 4 This is a schematic cross-sectional view of another circuit board backdrill test module provided by the present invention, with reference to FIG. Figure 1 and Figure 4As shown, when the first test hole 101 set in the first test hole setting area at least penetrates the inner layers from the back-drilling starting layer 3 to the second conductive layer 6, the first test portion 11 of the first test signal line 110 set in the first conductive layer 5 and the second test signal line 120 set in the second conductive layer 6 are both in a disconnected state; at this time, power signals are respectively introduced into the first test portion 11 and the second test signal line 120 on both sides of the first test hole 101, and the first test portion 11 and the second test signal line 120 on both sides of the first test hole 101 are both in an open circuit state, thereby determining that the first test hole 101 penetrates the second conductive layer 6 and that the first test hole 101 has a problem of being drilled too deep, thereby determining that the back-drilled hole formed in the same back-drilling process as the first test hole 101 has a problem of being drilled too deep.

[0056] In yet another exemplary embodiment, Figure 5 This is a schematic top view of another circuit board backdrill test module provided by an embodiment of the present invention. Figure 5 As shown, when the second test hole 102 set in the second test hole setting area 2 overlaps with the second test part 12, if there is no problem of shallow drilling at this time, the second test hole 102 will pass through the second test part 12, and the second test parts 12 on both sides of the second test hole 102 will be in a disconnected state; at this time, a power signal is passed through the second test parts 12 on both sides of the second test hole 102, and the second test parts 12 on both sides of the second test hole 102 will be in an open circuit state, thereby determining that the setting position of the second test hole 102 has shifted, and the second test hole 102 has a misalignment problem, thereby determining that the back-drilled hole formed in the same back-drilling process as the second test hole 102 has a drilling misalignment problem.

[0057] It should be noted that Figures 1 to 5 The technical solution of the embodiment of the present invention is described by taking as an example that each test hole group includes a first test hole setting area and a second test hole setting area. In the present invention, each test hole group may also include multiple first test hole setting areas and multiple second test hole setting areas, for example Figure 6 As shown, each test hole group can include four first test hole arrangement areas 1 and four second test hole arrangement areas 2. Furthermore, the number of first test hole arrangement areas and the number of second test hole arrangement areas in the same test hole group can be the same or different, and this is not specifically limited in the present embodiment. For ease of description, unless otherwise specified, the present embodiment of the utility model uses the example of the same number of first test hole arrangement areas and the same number of second test hole arrangement areas in the same test hole group as an example to illustrate the technical solutions of the present embodiment of the utility model.

[0058] In this embodiment, at least one test hole group is set, and each test hole group includes at least one first test hole setting area and at least one second test hole setting area, and the first test hole setting area and the second test hole setting area are respectively set with the first test hole and the second test hole setting area under the same back drilling process as the back drilling hole in the circuit board, so that the penetration layer and position offset of the first test hole and the second test hole can be consistent with the back drilling hole, so that the penetration module and position offset of the back drilling hole can be determined by testing the penetration layer and position offset of the first test hole and the second test hole; at the same time, a first test signal line is set in the second conductive layer between the back drilling hole starting layer and the back drilling hole finishing layer, and a second test signal line is set in the second conductive layer located on the side of the back drilling hole finishing layer away from the back drilling hole starting layer. A test signal line is provided, and by making the first test hole setting area overlap with the first test portion of the first test signal line and the second test signal line, and the second test portion of the first test signal line is at least partially set around the second test hole setting area, and by determining the on-off state of the first test portion and the on-off state of the second test signal line, the drilling depth of the first test hole set in the first test hole setting area can be determined, so that the drilling depth of the back drilled hole can be determined based on the drilling depth, and whether the back drilled hole is drilled too deep or too shallow can be detected, and by detecting the on-off state of the second test portion, whether the position of the second test hole set in the second test hole setting area is offset, so that the position of the back drilled hole can be detected based on the position offset of the second test hole. The utility model can simultaneously detect the drilling depth and alignment of the back drilled hole through a simple structure, and can reduce the size of the structure of the back drilled hole test module, which is conducive to improving test efficiency, simplifying test methods, and reducing test costs.

[0059] Optional, continue to refer to Figure 6 The backdrill test module 10 for a circuit board further includes a first test structure 01, a second test structure 02, and a third test structure 03. The first test structure 01 is electrically connected to the first end 111 of the first test section 11, the second test structure 02 is electrically connected to the second end 112 of the first test section 11 and the first end 121 of the second test section 12, and the third test structure 03 is electrically connected to the second end 122 of the second test section 12.

[0060] Specifically, by connecting a power signal between the first test structure 01 and the second test structure 02, the on-off condition of the first test part 11 can be tested to determine whether the first test hole set in the first test hole setting area 1 is too shallow. And by connecting a power signal between the second test structure 02 and the third test structure 03, the on-off condition of the second test part 12 can be tested to determine whether the second test hole set in the second test hole setting area 2 is not accurately aligned. In this way, by making the first test part 11 and the second test part 12 share the second test structure 02, the drilling depth and drilling alignment can be detected simultaneously, which is conducive to simplifying the structure of the back drilling test module and reducing the size occupied by the back drilling test module, so that it can be applied to circuit boards with smaller sizes, which is conducive to broadening the application field of circuit boards.

[0061] Optional, continue to refer to Figure 6 The backdrill test module of the circuit board further includes a fourth test structure 04 and a fifth test structure 05 , and the second test signal line 210 is electrically connected between the fourth test structure 04 and the fifth test structure 05 .

[0062] Specifically, by connecting a power signal between the fourth test structure 04 and the fifth test structure 05, the on / off status of the second test signal line 210 can be detected to determine whether the first test hole set in the first test hole setting area 1 is drilled too deep. In this way, the drilling depth of the first test hole can be detected using a simple structure, ensuring the accuracy of the first test hole drilling depth detection and improving the efficiency of the first test hole drilling depth detection.

[0063] It is understood that the first test structure 01, the second test structure 02, the third test structure 03, the fourth test structure 04, and the fifth test structure 05 can all be electrically connected to corresponding test signal lines, and can test the first test signal line 110 and the second test signal line without slicing the backdrill test module. The specific design can be based on actual needs. In an optional embodiment, the first test structure 01, the second test structure 02, the third test structure 03, the fourth test structure 04, and the fifth test structure 05 can include pads and / or conductive vias.

[0064] Optional, continue to refer to Figure 6 The first test portion 11 includes a first connecting segment a, a second connecting segment b, and at least one branch segment c corresponding to at least one first test hole setting area 1, and the two ends of the branch segment c are respectively connected to the first connecting segment a and the second connecting segment b.

[0065] It is understandable that the number of branch segments c in the first test portion 11 may be the same as or different from the number of first test hole setting areas 1 in the same test hole group, and may be designed according to actual needs. The embodiment of the present utility model does not make any specific limitation on this.

[0066] In an optional embodiment, in order to improve the accuracy of the drilling depth test of the first test hole set in each first test hole setting area 1, the number of branch segments c in the first test portion 11 can be the same as the number of first test hole setting areas 1 of the same test hole group, that is, one first test hole setting area 1 overlaps with one branch segment c. In this way, when the first test portion 11 includes multiple branch segments c, by detecting the electrical signal between the first connecting segment a and the second connecting segment b, it can be determined whether there is a conductive branch segment in each branch segment c electrically connected between the first connecting segment a and the second connecting segment b, and when there is a conductive branch segment, the first connecting segment a and the second connecting segment b will be in a short-circuit state when the power signal is connected, that is, there is a first test hole that does not penetrate the first conductive layer; conversely, when the first connecting segment a and the second connecting segment b are in an open-circuit state, it can be determined that the first test holes set at each branch segment c have penetrated the first conductive layer. In this way, by checking the on-off status between the first connecting segment a and the second connecting segment b, it can be determined whether there are test holes that are drilled too shallowly in the first test holes set at each branch segment c. While simplifying the structure of the back-drilling test module, there is no need to test each first test hole separately, which is conducive to improving test efficiency.

[0067] Optional, continue to refer to Figure 6 The second testing portion 12 includes a plurality of third connecting segments d and an open ring segment e connected between two adjacent third connecting segments d, and the open ring segment e surrounds the second testing hole setting area 2.

[0068] The shape of the open annular segment e can be similar to that of the second test hole setting area 2, that is, the open annular segment e can partially surround the second test hole setting area 2, and the inner ring edge of the open annular segment e can overlap with the edge of the second test hole setting area 2. In this case, in a direction parallel to the plane of the first conductive layer, the size of the second test hole setting area 1 can be equal to the inner ring size of the open annular segment e. In this way, when the second test hole set in the second test hole setting area 1 has a small offset, it will overlap with the open annular segment e, thereby disconnecting the open annular segment e, which is beneficial for improving the accuracy of the second test hole drilling offset test.

[0069] Optional, Figure 7 This is a schematic diagram of a top view of a backdrill test module for a circuit board provided by an embodiment of the present invention. Figure 7As shown, when the backdrill test module of the circuit board includes multiple test hole groups, the line widths of the open ring segments e around the second test hole setting areas 2 of at least two test hole groups are different.

[0070] For example, taking the backdrill test module of a circuit board including two test hole groups as an example, the line widths of the open ring segment e around the second test hole setting area 2 of the two test hole groups are different. For example, the line width of the open ring segment e around the second test hole setting area 2a of one test hole group can be w1, and the line width of the open ring segment e around the second test hole setting area 2b of the other test hole group can be w2. At this time, w1≠w2, so that w1 and w2 can be designed according to the drilling offset error accuracy of the specific backdrilled hole, that is, the line width of the open ring segment e around the second test hole setting area where the second test hole corresponding to the backdrilled hole with higher precision requirement is located is smaller, while the line width of the open ring segment e around the second test hole setting area where the second test hole corresponding to the backdrilled hole with lower precision requirement is larger.

[0071] Correspondingly, when a test hole group includes multiple second test hole setting areas, the line widths of the open ring segments e around the second test hole setting areas in the same test hole group may also be the same or different, and can be specifically designed according to actual needs.

[0072] For example, Figure 8 As shown, when there are multiple second test hole setting areas in the same test hole group, and the at least two second test hole setting areas include the second A test hole setting area 2a, the second B test hole area 2b and the second C test hole area 2c, the line width of the open ring segment e01 around the first A test hole setting area 2a is w01, the line width of the open ring segment e02 around the second B test hole area 2b is w02, and the line width of the open ring segment e03 around the second C test hole area 2c is w03, wherein w01, w02 and w03 are different. At this time, in order to further confirm the back-drilling that has occurred drilling offset, a test structure 061 can be set at the third connecting segment d01 between the open annular segment e01 and the open annular segment e02, and a test structure 062 can be set at the third connecting segment d02 between the open annular segment e02 and the open annular segment e03, so as to determine the drilling offset of the second test hole set in the second A test hole setting area 2a by detecting the continuity of the signal line between the second test structure 02 and the test structure 061, determine the drilling offset of the second test hole set in the second B test hole setting area 2b by detecting the continuity of the signal line between the test structure 061 and the test structure 062, and determine the drilling offset of the second test hole set in the second C test hole setting area 2c by detecting the continuity of the signal line between the test structure 062 and the third test structure 03.

[0073] In addition, in the direction parallel to the plane where the first conductive layer is located, the value range of the opening size L of the open ring segment e can also be designed according to actual needs. The embodiment of the utility model does not make specific limitations on this. In an optional embodiment, in order to meet the opening process requirements, the opening size of the open ring segment e can be about 3 mil.

[0074] Optional, Figure 9 This is a schematic diagram of a top view of a backdrill test module for a circuit board provided by an embodiment of the present invention. Figure 9 As shown, when the second test portion 2 includes multiple open ring segments e, any two adjacent open ring segments e have opposite opening directions. This allows the current paths between the adjacent open ring segments e to cancel each other out, reducing the possibility of electromagnetic interference, effectively minimizing signal crosstalk and interference, and improving the accuracy and reliability of the test signal. This effectively avoids the negative impact of electromagnetic interference on the backdrill test, thereby improving the accuracy and reliability of the backdrill test.

[0075] Optional, continue to refer to Figure 9 The second test signal line 210 includes a fourth connection segment f, a fifth connection segment g, and a sixth connection segment h connected between the fourth connection segment f and the fifth connection segment g. In a direction perpendicular to the plane where the first conductive layer 5 is located, each first test hole setting area 1 of the same test hole group overlaps with the sixth connection segment h.

[0076] Specifically, because the fourth connecting segment f, the sixth connecting segment h, and the fifth connecting segment g are sequentially connected, when a deeper first test hole is present among the first test holes disposed in the first test hole arrangement area 1 of the same test hole group, the sixth connecting segment h is disconnected. At this time, by detecting the continuity between the fourth connecting segment f and the fifth connecting segment g, it is possible to determine whether the deeper first test hole is present among the first test holes. This allows for accurate detection of the drilling depth of the first test holes while improving testing efficiency.

[0077] Based on the same utility model concept, the embodiment of the utility model further provides a circuit board, Figure 10 A schematic diagram of the structure of a circuit board provided in an embodiment of the present utility model is shown as follows: Figure 10 As shown, the circuit board 100 includes a circuit setting area 001 and a peripheral area 002 at least partially surrounding the circuit setting area. The circuit setting area 001 is provided with at least one backdrill hole 20, and the peripheral area 002 is provided with the backdrill test module 10 of the circuit board of the above embodiment.

[0078] Since the above-mentioned circuit board is provided with the circuit board backdrill test module provided by the above-mentioned embodiment of the present invention, it has the corresponding beneficial effects of the circuit board backdrill test module. For technical details not fully described in this embodiment, please refer to the circuit board backdrill test module provided by the above-mentioned embodiment of the present invention.

[0079] Since the circuit board described above is provided with the circuit board backdrill test module provided in the above-mentioned embodiment of the present invention, those skilled in the art will be able to understand the specific implementation and various variations of the circuit board of this embodiment based on the circuit board backdrill test module described in the embodiment of the present invention. Therefore, how this circuit board achieves the beneficial effects of the circuit board backdrill test module in the embodiment of the present invention will not be described in detail here. As long as those skilled in the art can implement the circuit board provided with the circuit board backdrill test module in the embodiment of the present invention, it falls within the scope of protection of this application.

[0080] The above specific embodiments do not limit the scope of protection of this utility model. Those skilled in the art will appreciate that various modifications, combinations, sub-combinations, and substitutions may be made based on design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model shall be included within the scope of protection of this utility model.

Claims

1. A backdrill test module for a circuit board, characterized in that: include: At least one test hole group; each of the test hole groups includes at least one first test hole setting area and at least one second test hole setting area; The first test hole setting area is used to set the first test hole under the same back drilling process as the back drilling process in the circuit board; The second test hole setting area is used to set the second test hole under the same back drilling process as the back drilling process in the circuit board; The backdrill test module of the circuit board at least includes a backdrilling start layer, a backdrilling end layer, a first conductive layer, and a second conductive layer; the backdrilled hole penetrates each inner layer from the backdrilling start layer to the backdrilling end layer; The first conductive layer is located between the back-drilled hole starting layer and the back-drilled hole finishing layer; the first conductive layer includes at least one first test signal line corresponding to at least one group of the test hole groups; the first test signal line includes a first test portion and a second test portion; The second conductive layer is located on a side of the backdrilled hole final drilling layer away from the backdrilled hole starting drilling layer; the second conductive layer includes at least one second test signal line corresponding to at least one group of the test hole groups; In a direction perpendicular to the plane where the first conductive layer is located, the first test hole setting area overlaps with the first test portion and the second test signal line, and the second test hole setting area does not overlap with either the first test portion or the second test signal line; the second test portion at least partially surrounds the second test hole setting area.

2. The circuit board backdrill test module according to claim 1, wherein: Also includes: a first test structure, a second test structure, and a third test structure; The first test structure is electrically connected to the first end of the first test section, the second test structure is electrically connected to the second end of the first test section and the first end of the second test section, and the third test structure is electrically connected to the second end of the second test section.

3. The circuit board backdrill test module according to claim 1, wherein: Also includes: a fourth test structure and a fifth test structure; The second test signal line is electrically connected between the fourth test structure and the fifth test structure.

4. The circuit board backdrill test module according to claim 1, wherein: The first testing portion includes a first connecting section, a second connecting section, and at least one branch section corresponding to at least one of the first testing hole setting areas; Both ends of the branch segment are connected to the first connecting segment and the second connecting segment respectively.

5. The circuit board backdrill test module according to claim 1, wherein: The second testing portion includes a plurality of third connecting segments and an open annular segment connected between two adjacent third connecting segments; The open annular segment surrounds the second testing hole setting area.

6. The circuit board backdrill test module according to claim 5, characterized in that: When the backdrill test module of the circuit board includes a plurality of test hole groups, the line widths of the open annular segments around the second test hole setting areas of at least two of the test hole groups are different.

7. The circuit board backdrill test module according to claim 5, characterized in that: When the second testing portion includes a plurality of open annular segments, the opening directions of any two adjacent open annular segments are opposite.

8. The circuit board backdrill test module according to claim 5, characterized in that: In a direction parallel to the plane where the first conductive layer is located, the size of the second test hole setting area is equal to the inner ring size of the open ring segment.

9. The circuit board backdrill test module according to claim 1, wherein: The second test signal line includes a fourth connecting section, a fifth connecting section, and a sixth connecting section connected between the fourth connecting section and the fifth connecting section; In a direction perpendicular to the plane where the first conductive layer is located, each first test hole arrangement area of ​​the same test hole group overlaps with the sixth connecting segment.

10. A circuit board, characterized in that: include: a circuit arrangement area and a peripheral area at least partially surrounding the circuit arrangement area; The circuit arrangement area is provided with at least one back-drilled hole; The peripheral area is provided with a backdrill test module for a circuit board according to any one of claims 1 to 9.

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