CN117858348A - Back drilling depth detection method - Google Patents
Back drilling depth detection method Download PDFInfo
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- CN117858348A CN117858348A CN202311849683.3A CN202311849683A CN117858348A CN 117858348 A CN117858348 A CN 117858348A CN 202311849683 A CN202311849683 A CN 202311849683A CN 117858348 A CN117858348 A CN 117858348A
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- test
- back drilling
- holes
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- depth
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- 238000005553 drilling Methods 0.000 title claims abstract description 83
- 238000001514 detection method Methods 0.000 title claims abstract description 34
- 238000012360 testing method Methods 0.000 claims abstract description 82
- 238000000034 method Methods 0.000 claims description 10
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 7
- 238000010586 diagram Methods 0.000 description 7
- 229910052802 copper Inorganic materials 0.000 description 6
- 239000010949 copper Substances 0.000 description 6
- 238000004519 manufacturing process Methods 0.000 description 4
- 230000001066 destructive effect Effects 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 230000007547 defect Effects 0.000 description 2
- 238000007747 plating Methods 0.000 description 2
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 238000003908 quality control method Methods 0.000 description 1
- 230000008054 signal transmission Effects 0.000 description 1
- 238000005476 soldering Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
Abstract
The invention discloses a back drilling depth detection method which comprises the steps of setting a back drilling module, determining a back drilling depth range, setting a detection module and testing on-off paths among each group of test holes. According to the invention, the test back drilling hole and the detection module are arranged in the board edge area of the printed circuit board, so that the back drilling hole depth information can be detected quickly, the use area is small, the back drilling hole with a smaller diameter can be detected, the nondestructive detection is realized, and the detection and analysis result speed is very high.
Description
Technical Field
The invention relates to the technical field of PCB drilling and circuit design, in particular to a back drilling depth detection method.
Background
At present, in the manufacturing process of a printed circuit board (Printed Circuit Board, PCB), copper plated through holes can be regarded as lines, and the ends of some copper plated through holes are not connected, so that signal retractions are caused, resonance is also reduced, reflection, scattering or delay of signal transmission can be caused, and finally, the problem of signal distortion is caused. The back-drilling process (back-drilling) removes the via copper from the via segments without any connection or transmission to avoid the problem of the signal "distortion" caused by the via copper residue in this portion. The hole drilled by the back drilling process is a back drilling hole (back drilling hole), and the back drilling hole is manufactured by the following steps: and finally, drilling an inverted grain bin-shaped hole with a cone below and a cylinder above on the soldering tin surface of the PCB, wherein the diameter of the hole is larger than that of the copper plating through hole, so that the hole copper on the inner wall of the copper plating through hole can be removed. In quality control of the back drilling process, back drilling depth control is a key factor affecting signal integrity, and therefore back drilling depth must be effectively managed in PCB actual production.
Currently, there are two main methods for back drilling depth detection:
the first method, where the back drill position is detected using a depth gauge, has the advantage of a non-destructive inspection, enabling visual representation of the data and rapid provision of results. However, this method has certain limitations for smaller diameter back holes, which cannot be measured.
In the second method, the back drilling position is used for manufacturing a metallographic section to measure the back drilling depth, and the method has the advantages of providing accurate data and detecting the back drilling depth with smaller diameter. However, the method has the defects of destructive detection, poor timeliness of the provided result, often needs to debug the back drilling depth for testing the first piece in normal back drilling production, and is not suitable for the occasion because of the poor timeliness of the slicing mode.
In view of this, the present invention has been made.
Disclosure of Invention
In order to overcome the defects, the invention provides a back drilling depth detection method which can not only rapidly provide back drilling depth information, but also detect back drilling holes with smaller diameters.
The technical scheme adopted by the invention for solving the technical problems is as follows:
a backdrilling depth detection method, comprising:
setting a back drilling module, setting the back drilling module in a board edge area of a Printed Circuit Board (PCB), and drilling a test back drilling hole with the depth consistent with that of the back drilling hole to be tested on the back drilling module;
determining a back drilling depth range, and setting at least two layers with adjacent corresponding depths as test layers according to the number of layers of the circuit board which are required to reach the back drilling depth;
setting a test module, and setting a plurality of pairs of through holes around a test back drilling hole of the back drilling module to form a test hole; the logarithm of the test holes is consistent with that of the test layers, each pair of test holes are connected between the corresponding test layers through lines, and the connecting lines of each pair of test holes pass through the center position of the test back drilling hole;
testing the on-off path between each group of test holes, if the path is between one group of test holes, indicating that the corresponding test layers of the group of test holes are conducted, and the back drilling depth does not reach the layer; otherwise, if the test holes are open, the test layers corresponding to the test holes are disconnected, and the back drilling depth reaches the layer.
As a further improvement of the invention, when the depth range of the back drill is determined, three layers with adjacent corresponding depths are set as test layers according to the number of layers of the circuit board which are required to be reached by the depth of the back drill.
As a further improvement of the invention, each group of test holes is identified when the test module is arranged.
As a further improvement of the invention, the test wells and the corresponding test layers are identified by the same numerals.
As a further improvement of the invention, when the test module is arranged, each group of test holes are correspondingly arranged outside two opposite sides of the test back drilling hole.
As a further improvement of the invention, a multimeter is used for measuring the on-off state of each group of test holes.
The beneficial effects of the invention are as follows: according to the invention, the test back drilling hole and the detection module are arranged in the board edge area of the printed circuit board, so that the back drilling hole depth information can be detected quickly, the use area is small, the back drilling hole with a smaller diameter can be detected, the nondestructive detection is realized, and the detection and analysis result speed is very high.
Drawings
FIG. 1 is a schematic diagram of a back drilling depth requirement structure according to an embodiment of the present invention;
FIG. 2 is a schematic diagram showing the distribution of test wells according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of a circuit board surface of a layer 4 according to an embodiment of the present invention;
FIG. 4 is a schematic diagram of a circuit board surface of a 5 th layer according to an embodiment of the present invention;
fig. 5 is a schematic diagram of a circuit board surface of a layer 6 according to an embodiment of the invention.
Detailed Description
A preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.
Referring to fig. 1, taking an 8-layer circuit board as an example, the back drilling depth requirement stays between 5 and 6 layers, the back drilling depth detection method specifically comprises the following steps:
firstly, setting a back drilling module, setting the back drilling module in a board edge area of a Printed Circuit Board (PCB), and drilling a test back drilling hole with the depth consistent with that of the back drilling hole to be tested on the back drilling module;
secondly, determining a back drilling depth range, and setting the 4 th to 6 th circuit layers as test layers according to the number of circuit board layers, namely 5 to 6 layers, which are required to reach the back drilling depth;
then, setting a test module, and setting 3 pairs of via holes around a test back drilling hole of the back drilling module to form 3 pairs of test holes; meanwhile, the numbers of 3 pairs of test holes are respectively and correspondingly marked as 3, 4 and 5, referring to fig. 2, and each group of test holes is provided with a connecting circuit at a corresponding circuit layer to conduct the test holes, referring to fig. 3, which is a schematic diagram of the circuit board surface of the 4 th layer, and the test holes of the 4 th layer and the 4 th layer are communicated; referring to fig. 4, a schematic diagram of a circuit board surface of layer 5 is shown, and a pair of test holes of 5 marks on layer 5 are communicated; referring to fig. 5, a schematic view of a circuit board surface of layer 6 is shown, and a pair of test holes of layer 6 and reference numeral 6 are communicated;
finally, testing the on-off path between each group of test holes by adopting a universal meter, and if the path is between one group of test holes, indicating that the corresponding test layers of the group of test holes are conducted, wherein the back drilling depth does not reach the layer; otherwise, if the test holes are open, the test layers corresponding to the test holes are disconnected, and the back drilling depth reaches the layer.
The detection module provided by the invention can be arranged in the edge area of the PCB, only one single back drilling module and the matched detection module are needed, the structure is simple, and the conductive holes of the detection module are surrounded around the back drilling module, so that the use area of the detection module is greatly reduced;
the detection module provided by the invention can accurately simulate the back drilling condition of the unit in the actual circuit board, and simultaneously uses an electric test method for detection, thereby avoiding destructive detection and having high detection and analysis structure speed.
Therefore, the invention can not only rapidly detect the back drilling depth information, but also has small use area, can detect the back drilling with smaller diameter, is nondestructive detection, and has very high detection and analysis result speed by arranging the test back drilling and the detection module in the board edge area of the printed circuit board.
In the above description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. The foregoing description is only of a preferred embodiment of the invention, which can be practiced in many other ways than as described herein, so that the invention is not limited to the specific implementations disclosed above. While the foregoing disclosure has been described with reference to certain embodiments, it will be understood by those skilled in the art that various changes and modifications may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. Any simple modification, equivalent variation and modification of the above embodiments according to the technical substance of the present invention without departing from the technical solution of the present invention still falls within the scope of the technical solution of the present invention.
Claims (6)
1. A backdrilling depth detection method, the method comprising:
setting a back drilling module, setting the back drilling module in a board edge area of a Printed Circuit Board (PCB), and drilling a test back drilling hole with the depth consistent with that of the back drilling hole to be tested on the back drilling module;
determining a back drilling depth range, and setting at least two layers with adjacent corresponding depths as test layers according to the number of layers of the circuit board which are required to reach the back drilling depth;
setting a detection module, and setting a plurality of pairs of through holes around a test back drilling hole of the back drilling module to form a test hole; the logarithm of the test holes is consistent with that of the test layers, each pair of test holes are connected between the corresponding test layers through lines, and the connecting lines of each pair of test holes pass through the center position of the test back drilling hole;
testing the on-off path between each group of test holes, if the path is between one group of test holes, indicating that the corresponding test layers of the group of test holes are conducted, and the back drilling depth does not reach the layer; otherwise, if the test holes are open, the test layers corresponding to the test holes are disconnected, and the back drilling depth reaches the layer.
2. The backdrilling depth detection method of claim 1, wherein: when the back drilling depth range is determined, three layers with adjacent corresponding depths are set to be used as test layers according to the number of layers of the circuit board, which is required to be reached by the back drilling depth.
3. The backdrilling depth detection method of claim 1, wherein: and when the test module is arranged, marking each group of test holes.
4. A backdrilling depth detection method according to claim 3, wherein: and identifying the test holes and the corresponding test layers by adopting the same numbers.
5. The backdrilling depth detection method of claim 1, wherein: when the test module is arranged, each group of test holes are correspondingly arranged outside two opposite sides of the test back drilling hole.
6. The backdrilling depth detection method of claim 1, wherein: and when testing the on-off paths between each group of test holes, measuring by adopting a universal meter.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311849683.3A CN117858348A (en) | 2023-12-29 | 2023-12-29 | Back drilling depth detection method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311849683.3A CN117858348A (en) | 2023-12-29 | 2023-12-29 | Back drilling depth detection method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117858348A true CN117858348A (en) | 2024-04-09 |
Family
ID=90539551
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311849683.3A Pending CN117858348A (en) | 2023-12-29 | 2023-12-29 | Back drilling depth detection method |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117858348A (en) |
-
2023
- 2023-12-29 CN CN202311849683.3A patent/CN117858348A/en active Pending
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