TWI618940B - Device and method for detecting blind hole of printed circuit board - Google Patents

Abstract

The invention provides a blind hole detection device and method for a printed circuit board. The blind hole detection method includes the following steps: a blind hole feature learning step, using an actual printed circuit board finished product as the same board, and scanning any of a plurality of blind holes on the template. The blind hole image is used as a learning object; the standard information creation step is to obtain the positions of a plurality of blind holes on the template based on the blind hole feature learning step, and use the image characteristics of at least one blind hole on the template to establish standard information; statistics The calculation step is to scan a test board with the same process as the template, and obtain the test information of a plurality of blind holes on the test board, and then calculate the deviation statistics of the test information and the standard information; the result display step uses the image Or the graph shows output deviation information.

Description

Device and method for detecting blind hole of printed circuit board

The invention relates to a blind hole detection device and method, in particular to a blind hole detection device and method for quality detection of a plurality of blind holes on a printed circuit board.

In the manufacturing process of printed circuit boards, they are roughly divided into main stations such as inner layer stations, crimping stations, drilling stations, and inspection stations in order. First, the printed circuit boards are completed with development and etching processes at the inner layer stations. Enter the pressing station for blackening / browning, and press the printed circuit board for multiple times at the pressing station. The pressed printed circuit board then goes to the drilling station for laser drilling. After the drilling is completed, the printed circuit board is washed, and finally the printed circuit board is sent to an inspection station for optical drilling quality inspection.

In the quality inspection part of the inspection station, the patent No. CN1278100C "Blind hole quality analysis method of printed circuit board" has disclosed a blind hole quality analysis method of the inspection station, which is first inputted to laser processing blind holes on the printed circuit board. Design data and actual measurement data, and use the design data and measurement data to calculate various deviation statistics. The deviation statistics are expressed in the form of target map, hole offset distribution map, vector map, and pad area ratio distribution map. And residual area ratio distribution maps. These charts can be used to display copper window information, pad information, or relative information between copper windows and pads. Finally, these information can clearly show the manufacturing quality of laser blind holes on printed circuit boards.

However, after repeated pressing of the printed circuit board, the board will expand and contract, which will cause the original design data to differ greatly from the actual measurement data, which will cause a lot of errors in the statistics. Misinformation makes it impossible for the operator to judge whether the process is missing based on the misinformation. In addition, the printed circuit board needs to be cleaned after drilling and the residual adhesive and blackening / browning layer to perform optical drilling quality inspection. Direct inspection after drilling, which is also extremely inconvenient in use.

That is, the purpose of the present invention is to provide a blind hole detection device and method for a printed circuit board which can overcome the defects of design data and is convenient to use.

The blind hole detection method of a printed circuit board according to the purpose of the present invention is implemented by a detection device to check the blind holes of the printed circuit board. The blind hole detection method includes the following steps: a blind hole feature learning step, so that the detection device uses Any blind hole image in the plurality of blind holes of the image of at least one plate is used as a learning object, and the at least one plate is an actual printed circuit board finished product; standard information establishing steps enable the detection device to learn the characteristics of the blind holes. On the basis of obtaining the positions of the plurality of blind holes on the at least one plate, and using the image features of the at least one blind hole on the at least one plate to establish standard information; a statistical operation step that makes the detection device Scan the image of the test board with the same process, and obtain the test information of a plurality of blind holes on the test board according to the method described in the standard information creation step, and then calculate the deviation statistics of the test information and the standard information; and A result display step, so that the detection device correspondingly outputs an image or a chart after the deviation statistics of the statistical operation step are calculated. A deviation information.

The blind hole detection device of a printed circuit board for the purpose of the present invention is used to execute the blind hole detection method of the printed circuit board, and includes: a detection device capable of performing image scanning and calculating deviation statistics.

The blind hole detection method for a printed circuit board in the embodiment of the present invention uses an actual printed circuit board finished product as a template, and uses the blind hole characteristics on the template as standard information, which overcomes the gap between the design data and the finished product, and detects and analyzes The results will be closer to the actual results after the printed circuit board is pressed and drilled; and because the standard information and the information to be tested are obtained from the finished printed circuit board, The printed circuit board products before and after cleaning can be directly inspected, which improves the convenience for the operator.

S1‧‧‧Steps of establishing optical positioning point

S2‧‧‧ blind hole feature learning steps

S3‧‧‧Standard information creation steps

S4‧‧‧Statistical operation steps

S5‧‧‧Result display steps

6, 6’‧‧‧ printed circuit board

a, b, c‧‧‧ model

a01‧‧‧blind hole

a11‧‧‧Bronze window

a12‧‧‧pad

a13‧‧‧residue

a14‧‧‧perforation

A1‧‧‧Bronze window radius

A2‧‧‧pad radius

C1‧‧‧Bronze Window Center

C2‧‧‧ land center

FIG. 1 is a flowchart of an embodiment of a blind hole detection method for a printed circuit board according to the present invention.

FIG. 2 is a machine vision image of a blackened / brownized / uncleaned printed circuit board according to an embodiment of the present invention.

FIG. 3 is a machine vision image diagram of a printed circuit board after cleaning and removing glue in an embodiment of the present invention.

FIG. 4 is a machine vision image diagram of a blind hole of a template in an embodiment of the present invention.

FIG. 5 is a machine vision image diagram showing a missing state of a blind hole in an embodiment of the present invention.

FIG. 6 is a machine vision image diagram showing a state of no pad of a blind hole in the embodiment of the present invention.

FIG. 7 is a machine vision image diagram showing an oversized copper window of a blind hole in an embodiment of the present invention.

8 is a machine vision image diagram showing a state where a copper window of a blind hole is too small in an embodiment of the present invention.

FIG. 9 is a machine vision image diagram showing a state where a pad of a blind hole is too small in an embodiment of the present invention.

FIG. 10 is a machine vision image diagram showing a hole deviation state of a blind hole in the embodiment of the present invention.

FIG. 11 is a machine vision image diagram showing a state of adhesive residue of a blind hole in the embodiment of the present invention.

FIG. 12 is a machine vision image diagram showing a breakdown state of a blind hole in the embodiment of the present invention.

FIG. 13 is a defect distribution chart shown in the embodiment of the present invention.

FIG. 14 is a scatter diagram of the deviation amount of the entire blind hole of the test board and the template in the embodiment of the present invention.

FIG. 15 is a matching schematic diagram of matching template a, template b and template c to obtain matching information according to an embodiment of the present invention.

As shown in FIGS. 1 and 4, the embodiment of the blind hole detection method for a blind hole detection device of a printed circuit board of the present invention for detecting the blind hole a01 of a printed circuit board is based on an actual printed circuit board. The circuit board is used as a template to detect and analyze the blind holes of other printed circuit boards with the same process. The printed circuit board may be the blackened / brown / unwashed and removed printed circuit board 6 shown in FIG. 2, or The printed circuit board 6 'shown in FIG. 3 is cleaned and removed, but the implementation is not limited thereto. For convenience of description, in the following embodiments, the printed circuit board 6 'after cleaning and de-gluing shown in FIG. 3 is taken as an example for description. The blind hole detection method includes the following steps: Step S1 of establishing an optical positioning point: Take a printed circuit board as a template a, and make the detection device image scan the template a to record the hole position coordinates of a plurality of holes on the template a to establish a plurality of optical positioning points (Not shown), these optical positioning points can be used to quickly find the corresponding optical positioning points on other templates and test boards, and can be used to locate other templates and test boards to be tested. The holes can be Mechanical drilling or laser blind hole.

Blind hole feature learning step S2: Make the detection device scan the image of the template a obtained according to the step S1 of establishing an optical positioning point, and select any blind hole a01 image of the plurality of blind holes a01 on the template a as a learning object. Record the gray scale, diameter, and center information of a copper window a11 and a pad a12 of the blind hole a01. The blind hole a01 can be located in the blackened / brownized / uncleaned printed circuit shown in Figure 2. On the board 6, or the printed circuit board 6 'after cleaning and de-gluing shown in FIG. 3, the blind hole a01 has a copper window a11 and a pad a12; the standard information establishing step S3: the detection device is placed in the blind Based on the hole feature learning step S2, determine and obtain the positions of a plurality of blind holes a01 on the template a and record their center coordinates, and use the features of the image (Figure 4) of at least one blind hole a01 on the template a Contains standard information of the radius A1 of the copper window a11, the center C of the copper window a11, the radius A2 of the pad a12, the center C2 of the pad a12, and the like; statistical operation step S4: enabling the detection device to complete the standard After the information creation step S3, the Scan the image of the board under test during the manufacturing process, obtain multiple optical positioning points of the board under test according to the method described in step S1 of establishing an optical positioning point, and locate the board under test, and The method described in the standard information establishing step S3 obtains the test information of a plurality of blind holes a01 on the test board, and then calculates the deviation statistics of the test information and the standard information to generate a deviation information; The board to be tested refers to if the template a is a blackened / brown / uncleaned debonded printed circuit board, then the board to be tested is also a blackened / brown / unwashed debonded printed circuit board. a is the printed circuit board after cleaning and de-gluing, then the board under test is also the printed circuit board after cleaning and de-gluing; the result shows step S5: after the deviation statistics of the statistical operation step S4 are calculated by the detection device, The deviation information is displayed by images or charts such as machine vision image maps, defect distribution charts, hole target maps, and process capability index (CPK) data; machine vision image maps include miss maps (Figure 5), and padless maps (Figure 6), copper window is too large (Figure 7), copper window is too small (Figure 8), pad is too small (Figure 9), hole deviation (Figure 10), residual glue with residual glue a13 (Figure 11) A breakdown chart with perforations a14 (Figure 12); the above mentioned defect distribution chart (Figure 13) shows the above types of defects (Figures 5 to 12) Distribution locations on the printed circuit board to be tested; Figure 14 is a scatter diagram of the deviation of the entire blind hole a01 of the test board and the template a, and the X-axis and Y-axis represent the test The deviation between the information and the standard information in two vertical directions shows the dispersion of the deviation of the entire blind hole a01.

In the implementation of the embodiment of the present invention, after the operator interprets the image or chart displaying the deviation information, if the quality of the blind hole of the test board and the template a is significantly different, it is roughly divided into two cases at this time. First, the quality of the blind hole a01 on the board to be tested is indeed defective due to process problems, and the second is that the template a itself has defects and generates erroneous standard information, so the operator can create step S3 in the standard information. In addition, multiple sample templates (two or more) are added in the test device, and the detection device takes the average value of the characteristics of multiple sample templates as the standard information for re-inspection, or when the test device performs the standard information establishment step S3 for the first time , Take the average value of the features of the plurality of templates as standard information; take FIG. 15 as an example, although the template a lacks a blind hole a01, but the detection device matches a template b with a template c After the information, it is found that the template b and the template c have a blind hole b01 and c01 at the same position, and it can be determined that the template a is missing. There is a blind hole a01, and the detection device uses the matching information as standard information.

The blind hole detection method of a printed circuit board in the embodiment of the present invention uses an actual printed circuit board finished product as a template, which overcomes the gap between the design data and the actual finished product, and enables the detection analysis result to be closer to the printed circuit board pressing and bonding. The actual results after drilling; and because the standard information and the information to be tested are obtained from the finished printed circuit board, the finished printed circuit board can be directly inspected whether it is before or after cleaning, which improves the operator's use of Convenience.

In the implementation, the method of matching the blind hole features on the plurality of templates and taking the average value of the blind hole features of the plurality of templates as the standard information can improve the accuracy of the standard information and make the detection and analysis results more accurate. accurate.

In addition, in implementation, in another embodiment of the present invention, the step S1 of establishing an optical positioning point is not necessary, and the action of the detection device scanning to obtain the image of the template a may be changed to the blind hole feature learning step S2 and executed. .

However, the above are only the preferred embodiments of the present invention. When the scope of implementation of the present invention cannot be limited by this, any simple equivalent changes and modifications made in accordance with the scope of the patent application and the description of the invention for the present invention are all Still within the scope of the invention patent.

S1‧‧‧ establish optical positioning point

S2‧‧‧ blind hole feature learning

S3‧‧‧ standard information creation

S4‧‧‧Statistical Operation

S5‧‧‧ Results show

Claims (12)

A blind hole detection method for a printed circuit board is implemented through a detection device to check the blind hole of the printed circuit board. The blind hole detection method includes the following steps: a blind hole feature learning step, so that the detection device uses at least the same board. Any blind hole image in the plurality of blind holes in the image is used as a learning object, and the at least one plate is an actual printed circuit board finished product; the standard information establishing step enables the detection device to obtain the blind hole feature learning step based on the blind hole feature learning step. The positions of the plurality of blind holes on the at least one plate, and the standard information is established by using the image features of one blind hole on the at least one plate; the statistical operation step enables the detection device to detect The DUT performs image scanning, and obtains the DUT of a plurality of blind holes on the DUT according to the method described in the standard information creation step, and then calculates the deviation statistics of the DUT and the standard information; and the result is displayed. In step, after the deviation statistics of the statistical operation step are calculated, the detection device outputs an offset data correspondingly in an image or a chart. . According to the blind hole detection method for a printed circuit board according to claim 1, the blind hole feature learning step includes recording grayscale, diameter, and center information of a copper window and a pad of the blind hole. According to the blind hole detection method for a printed circuit board according to claim 1, the standard information of the standard information establishing step includes a copper window diameter, a copper window center, a pad diameter, and a pad center. The blind hole detection method for a printed circuit board according to claim 1, further comprising a step of establishing an optical positioning point before the feature learning step of the blind hole. The step of establishing an optical positioning point scans and records a plurality of numbers on the at least one board. The coordinates of the hole position of each hole are used to establish the optical positioning point. This statistical operation step will follow the steps of establishing the optical positioning point. The method described above obtains a plurality of optical positioning points of the board under test to locate the board under test. According to the blind hole detection method for a printed circuit board according to claim 4, the hole may be a mechanical drill hole or a laser blind hole. According to the blind hole detection method for a printed circuit board according to claim 1, the standard information establishing step is to match the blind hole characteristics of a plurality of sample templates, and take the average value of the blind hole characteristics of the plurality of sample templates as the standard. Information. According to the blind hole detection method for a printed circuit board as described in claim 1, the at least one board in the statistical operation step is the same as the board under test or a blackened / brownized board or an uncleaned adhesive Printed circuit board. According to the blind hole detection method for a printed circuit board according to claim 1, the at least one board in the statistical operation step is the same as the board under test for the printed circuit board after cleaning and removal of glue. According to the blind hole detection method for a printed circuit board according to claim 1, the image or chart of the result display step includes, but is not limited to, a machine vision image chart, a defect distribution chart, a hole target chart, and process capability index data. According to the blind hole detection method for a printed circuit board according to claim 9, the machine vision image diagram includes but is not limited to a missing image, a no-pad image, a copper window too large, a copper window too small, a pad too small, Hole deviation map, adhesive map and breakdown map. According to the blind hole detection method for a printed circuit board according to claim 9, the defect distribution chart shows missing defects, no pad defects, oversized copper windows, undersized copper windows, underpad defects, hole deviation The distribution position of at least one of the defect, the adhesive defect and the breakdown defect on the printed circuit board. A blind hole detection device for a printed circuit board, which is used to perform the blind hole detection method for a printed circuit board according to any one of claims 1 to 11, and includes: a Detection device capable of image scanning and calculation of deviation statistics.