JPH0361839A - Inspecting apparatus for printed wiring board - Google Patents

Abstract

PURPOSE:To detect an etching remainder part and a defective part accurately by aligning the master data and the work data which are read out of a body to be inspected, comparing the work data whose position correction is finished with the master data, detecting a uncomformable disagreed part, and deciding the excessive parts in the disagreed parts to be remaining parts to be etched. CONSTITUTION:The disagreed data at a remaining parts to be etched and the disagreed data at a defective parts are separated by using comparing means 14. The disagreed data at the remaining parts to be etched are inspected in a first filter part. The disagreed data at the defective parts are inspected at the second filter part. As the master data, CAD data or the data which are read out of an actual board whose inspection is successful are used. By an alignment means 13, the wiring pattern on a printed wiring board is aligned with the wiring pattern of the master data. By the comparing means 14, the alignment of both data are compared, and the disagreed parts are detected. When the parts are excessive parts which are not present in the master pattern, the parts are decided to be the parts remaining to be etched. The parts which are not in the work data are decided as defective parts.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention can detect etching remaining portions or missing portions in a wiring pattern with high accuracy. The present invention relates to a printed wiring board inspection device.

[Prior art]

For wiring patterns provided on printed wiring boards.

As shown in FIG. 9, the etching may be insufficient for some reason, resulting in an etched portion 91 between the wiring patterns 9.9. The etched remaining part 9
1 electrically shorts between the wiring patterns 9 and 9.

On the other hand, if etching is excessive in some parts of the wiring pattern, as shown in FIG. 10, a missing portion 95 may occur in the middle of the wiring pattern 9. The missing portion 95 breaks the electrical connection within the wiring pattern 9.

Therefore, in the printed wiring board, the etching remaining portion 91. An inspection is performed to determine whether or not the missing portion 95 exists, and the printed wiring board is passed.
A selection of rejected candidates will be conducted.

Conventionally, as an inspection device used for such inspection.

Some use the comparative method. This inspection device is a method for determining the presence or absence of defects by directly comparing master data and workpiece data obtained from a wiring pattern on a printed wiring board, which is an object to be inspected. In the comparison method, the master data and the workpiece data are aligned (correction of the amount of deviation), and the mismatched portions between the two are checked.
Discrepancies larger than a certain size are output as defects.

As the master data, CAD data at the time of design may be used, or a printed wiring board that has passed actual inspection may be used and read by a CCD camera or the like.

[Problem to be solved]

However, in the above conventional method, when the master data is CAD data, it may not match the pattern width of the workpiece data and nine-position alignment may not be possible.

Furthermore, even if the master data is based on a printed wiring board that has passed inspection, complete alignment with the work data may not be possible due to etching residue or expansion and contraction of the product.

In this way, when the master data and the workpiece data are aligned, there is inevitably a small amount of deviation, so a defect with a size smaller than the amount of deviation cannot be detected even if it is a two-major defect.

Furthermore, since the above-mentioned conventional method simply determines defects based on the size of the mismatched portion, it overly detects etching unevenness that is not worthy of a major defect, resulting in a high false alarm rate.

In view of this problem, the present invention can detect etching remaining portions and missing portions with high accuracy.

The present invention aims to provide an inspection device for printed wiring boards.

[Means for solving problems]

The present invention provides an inspection device for inspecting defects in a wiring pattern on a printed wiring board, the inspection device including an imaging device for reading the wiring pattern.

a positioning means for positioning the workpiece data obtained by the imaging device and standard master data; and detecting a mismatched part by comparing the workpiece data aligned by the positioning means and the master data. and a comparison means that separates the data into discrepant data on the remaining etching area and data on the missing part, and passing the discrepant parts of a certain size or more among the discrepancy data on the remaining etching area obtained by the comparison means. a first filter section for selecting mismatched shapes; a first filter section for master checking that checks the pattern state of the position-corrected master data obtained by the alignment means; and a first filter section for calculating the logical sum of the outputs of the two filter sections. 1AND gate section, a second filter section for selecting mismatched shapes that passes mismatched portions of a certain size or more among the mismatch data of missing portions obtained by the comparison means, and a position correction obtained by the alignment means. A second master check filter unit that checks the pattern state of completed master data and a second AN that takes the logical sum of the outputs of the two filter units.
A print comprising a D-gate section, and a defect aggregation section for aggregating defect data of the remaining etched portion obtained by the first AND gate section and defect data of the missing section obtained by the second AND gate section. Found in wiring board inspection equipment.

What is most noteworthy about the present invention is that the comparison means separates the unmatched data of the remaining etched area and the unmatched data of the missing part, and then the unmatched data of the remaining etched part is processed by the Scheme 1 filter section. Discrepant data is checked by the second filter section.

In the present invention, the master data is as described above.
AD data and data read from actual boards that passed inspection are used.

Further, the 2-positioning means is a device that performs positioning between work data read from a printed wiring board, which is an object to be inspected, and standard master data. As a result, the wiring pattern on the printed wiring board,
Alignment is performed with respect to the wiring pattern of the master data, and preparations are made for comparison by the comparing means.

The comparison means compares both data aligned by the alignment means and detects a mismatched portion. When the mismatched portion is a surplus portion that does not exist in the mask pattern.

The mismatched portion is determined to be mismatched data of the "etching remaining portion". On the other hand, if the mismatched portion is a missing portion that exists in the mask pattern but does not exist in the work data, the mismatched portion is determined to be mismatched data of the “missing portion”. and.

The mismatch data of the former etched remaining portion is sent to the first filter section for selecting mismatched shapes, while the mismatch data of the missing portions is sent to the second filter section for selecting mismatched shapes.

The first and second filter sections for selecting mismatched shapes are:
This device is used to limit points of interest among discrepant data, and takes into account inspection shapes such as disconnections and shorts, as well as inspection item information. Adopt a filter shape. Just 9
- Unlike the boat fishing comparison method, this filter part does not need to cut out the mismatched portions of sizes that are less than one position misalignment type (see Examples).

The first and second filter sections for master checking check the master data using certain rules,
This is a device that outputs only when the rules are met.

As the master data, position-corrected master data obtained by the positioning means is used.

In this master check filter section, the check area Φ direction and distance of the master data to be checked are determined in advance, and these are set based on the position correction ability of the inspection device, detected defect items, etc. (Example)
.

What is required here is that the location of the image being processed by the mismatched shape selection filter and the location of the image being processed by the master check filter match. This essentially means checking the master data in the vicinity of the point where the mismatch has occurred at the same time.

1st. The second AND gate section is a device for calculating the logical sum of the re-outputs of the mismatched shape selection filter and the master check filter. When the mismatched shape has a certain shape and size and the master data conditions near that point match a certain rule, the output of the AND gate is enabled.

That is, true defect data is output.

The defect aggregation means is a device that aggregates the defect data output from the first and second AND gate sections.

The terminal is an output device for aggregated data.

[For production]

In the inspection apparatus of the present invention, the master data and the workpiece data read from the object to be inspected are aligned by the alignment means, and the workpiece data and master data, which have been corrected by one position, are sent to the comparison means. 9 in comparison means
Compare both data.

Detect discrepancies between the two. Then, the above-mentioned surplus portion of the mismatched portion is determined to be mismatch data of the etched remaining portion and is transmitted to the first filter section for mismatch shape selection.

On the other hand, the above-mentioned missing portion of the above-mentioned mismatched portion is as follows.

The second part is used to determine the missing part as unmatched data and select the unmatched shape.
Send to filter section.

Therefore, in the former first filter section for selecting mismatched shapes, mismatched portions smaller than a certain size are cut, and mismatched portions larger than that are passed through.

In parallel with this, the position-corrected master data sent from the first positioning means is sent to the first master check filter.

The first filter for master checking is a spatial filter with a rule that outputs if a certain finite area of the master is entirely a base material.

The first AND is the logical sum of the outputs of the two first filters.
By taking the data at the gate, the data of the true remaining etching area can be obtained. This comparative test.

It can also be viewed that a region in which no pattern portion of master data is present in the vicinity of the mismatched portion as the etching remaining portion is determined to be the etching remaining portion. The remaining etched data is sent to the defect counting section.

Comparative inspection is similarly performed on the second filter section for mismatching shape selection, the second filter section for master check, and the second AND gate section, but here, the base material portion of the master data is Rules are selected such that a part that does not exist is determined to be a true missing part. Data on true missing parts is sent to the defect aggregation unit.

〔effect〕

According to the present invention, the output of the comparison inspection is distinguished between mismatch data of the etching remaining area and mismatch data of the missing part, and the shape of the master data near the mismatching area is used for defect determination. It is possible to detect true missing parts with a high accuracy exceeding the capability of the position correction function.It is possible to provide a printed wiring board inspection device.

〔Example〕

This embodiment relates to an embodiment of the present invention. The printed wiring board inspection apparatus will be explained using FIGS. 1 to 5.

As shown in FIG. 1, this example device includes a printed wiring board 1
C as an imaging device that reads the wiring pattern 101 on 0
A CD camera 11, an A/D converter 12 that converts an analog signal of the COD camera 11 into a digital signal, and a positioning means 13.

Comparing means 14, a first filter section 15 for selecting mismatched shapes that inspects mismatch data on remaining etched portions, a first filter section 151 for master check, a first AND gate section 16, and a mismatch shape filter that inspects mismatch data on missing portions. Second filter section for sorting 17. A second master check filter section 171, a second AND gate section 18, and a defect aggregation section 31 that receives defect data signals from the first and second AND gate sections. and a terminal 32.

Further, the master storage means 21 is included in the first positioning means 13.
The master memory 21 having a value of 0 is connected.

The master adoption means 210 is a device that stores master data, which is standard image information. One such means is, for example, a means for converting CAD data (vector data) at the time of designing the wiring pattern to match work data (raster data) from an imaging device and using it as master data. Further, there is a means for storing data read from an acceptable wiring pattern (master board) using an imaging device in advance.

Moreover, in FIG. 1, the CCD camera 11. A
/D converter 12. A means is shown for taking in master data into the master memory 21 via a path 210 and transmitting the master data to the positioning means via a path 212 at the time of inspection.

However, when inspecting with the above inspection device,
First, the wiring pattern 101 on the printed wiring board 10 is
Read by CD camera 11.

Work data is input to the positioning means 13 via the A/D converter 12 . On the other hand, master data is input from the master memory 21 to the alignment means 13 through a path 212.

Then, the alignment means 13 aligns the work data and master data. However, as described above, complete position correction is impossible here, and there are always parts that cannot be corrected. Furthermore, in reality, there is a slight shape mismatch between the standard master data and the printed wiring board that is the product to be inspected.

Therefore, as described below, the comparison means 14 performs a preliminary comparison, and after separating the data into discrepancy data for the remaining etched part and the missing part, the final data is sent to the first or second filter for unmatched shape selection and master check, respectively. The inspection is carried out on

As the above-mentioned positioning means, 1, for example, JP-A-62-14
There is an apparatus shown in Japanese Patent No. 0009.

Next, the workpiece data and the master data, which have been subjected to positional correction by the third positioning means 13, are inputted to the comparing means 14, and the two are compared to detect information on mismatched portions. As for the information on this discrepancy.

It is assumed that the work data has a redundant pattern portion (the portion 91 in FIG. 2, which will be described later) with respect to the master data, and, conversely, there is a case where the work data has a pattern portion that is redundant with respect to the master data (the portion 95 in FIG. 4, which will be described later). Some say that it has a part). Here, the surplus pattern part of the former shows the etching remaining part.

This information is used as mismatch data for the etching remaining portion.

The latter one indicates a missing part, and this information is considered as mismatch data of the missing part.

The comparison means 14 may be a combination of logic elements as shown in FIG. 6, for example.

That is, the discrepancy data of the etching remaining portion is as follows.

As shown in FIG. 2, when the pattern 9 of the object to be inspected (inside the solid line frame) and the master pattern 8 (inside the dotted line frame) are compared, a mismatched portion 91 is detected. but,
Here, in addition to the mismatch data of the etching remaining portion, mismatch data based on the positional deviation 7 (hatched area) in both patterns 8 and 9 is also included. Positional deviation 7 is deviation i
It has lY.

In addition, the discrepancy data of the missing part is as shown in Figure 4.
When the pattern 9 of the object to be inspected and the master pattern 8 are compared, a mismatched portion 95 is detected. However, here, the 0 positional deviation 7, which includes the mismatched data based on the positional deviation 7 in both patterns 8 and 9, as well as the mismatched data of the missing portion, has a deviation amount Y.

Therefore, the comparison means 14 distinguishes between the two types of mismatch data, and the mismatch data of the remaining etched portion is sent to the first filter section 15 for mismatch shape selection, and the mismatch data of the missing portion is sent to the second filter section 15 for mismatch shape selection. Filter section 17
Output to.

In the first filter section 15 for unmatched shape selection, the unmatched data of the remaining etched portion is processed.

Due to the quantization error during conversion in the A/D converter 12, one image is cut, and a mismatched portion with a size of two pixels or more is passed. The mismatched data that passed.

The signal is output to the first AND gate section 16 (FIG. 7).

On the other hand, in the second filter unit 17 for 2-undefeated shape selection, the unmatched data of the missing part is checked for unmatched data that has a length (width is not required) that is 80% or more of the width of the pattern to be inspected. Let the department pass. A 1i-shaped filter is used. The passed mismatch data is output to the second AND gate section 18 (FIG. 8). This filter section is prepared for each direction.

The above-mentioned filter section is a spatial filter.

Next, the master data (mask image) is checked in the master check foil 1 or the second filter section. The master data used here is:

This is tentative position-corrected data obtained by the positioning means 13.

As shown in FIG. 3, the master check first filter section checks the state of the master pattern 8 in a circular area with a diameter twice the amount of displacement Y of the positional displacement 7 that always occurs.

Circular areas A, B, and C in the figure indicate the check areas. If there is a master pattern 8 (dotted line frame) in circular areas A and B, there is no output from the filter.

When there is no master pattern 8 in the circular area C, there is an output from the filter (Figure 7).
.

Next, in the second master check filter section, the state of the master pattern 8 is checked up to a linear area three times the length of the shift amount Y of one position shift 7, as shown in FIG. Linear areas J and L in the figure indicate the check areas. and,! 1m area J,
When the base material of the master is caught in a part of the area as shown in L, there is no output from the filter.

On the other hand, when the master pattern is caught in the entire area, such as in a linear area.

There is an output from the filter (Figure 8). however.

The direction of the one-dimensional check area is a direction that intersects the filter direction in the second filter section for mismatching shape selection by 90 degrees. For example, for mismatched data that has passed the filter in the horizontal direction, a master pattern is applied using a linear area in the vertical direction (FIG. 8).

The inspection results of the master check foil 1 and the second filter section are sent to the first and second AND gate sections, respectively.

The master check foil 1 and the second filter section are the same as the mismatched shape sorting filter section.

Use spatial filters.

FIGS. 7 and 8 show the relationship between the mismatched shape selection filter, the master check filter, and the AND gate section. AND
It is shown that true defect information is output from the gate output.

As described above, according to the inspection apparatus of the two examples, in order to distinguish between mismatched data of etched remaining areas and mismatched data of missing parts, and compare and inspect them with master data, it is possible to distinguish between the true remaining etched parts and the true missing parts. can be detected with high precision.

[Brief explanation of drawings]

1 to 5 show an inspection apparatus according to an embodiment of the present invention, FIG. 1 is an explanatory block diagram thereof, FIGS. 2 and 3 are explanatory diagrams of discrepancy data of etching remaining areas and comparative inspection thereof,
Figures 4 and 5 are explanatory diagrams of mismatch data for missing parts and their comparison inspection, Figure 6 is a logic circuit diagram of the comparing means, Figure 7 is an etching residue detection section, and Figure 8 is detection of missing parts. An explanatory diagram of the section. FIGS. 9 and 10 are explanatory diagrams of etched remaining portions and missing portions in the wiring pattern. 7゜8゜9゜91゜95゜ position shift. master pattern. Pattern of inspected object. Remaining part of etching. Missing part.

Claims (1)

[Claims] An inspection device for inspecting wiring pattern defects on a printed wiring board, the inspection device comprising: an imaging device for reading the wiring pattern, work data obtained by the imaging device, and a standard master. a positioning means for aligning the data, and a positioning means for comparing the workpiece data aligned by the positioning means with the master data to detect a mismatched part,
Comparison means for classifying mismatched data on remaining etched parts and mismatched data on missing parts, and mismatched shape selection for passing mismatched parts larger than a certain size among the mismatched data on leftover etched parts obtained by the comparison means. a first filter section for master checking that checks the pattern state of the position-corrected master data obtained by the alignment means, and a first AND gate section that takes the logical sum of the outputs of both filter sections. a second filter section for selecting mismatched shapes that passes mismatched portions of a certain size or more among the mismatch data of the missing portions obtained by the comparison means, and a position-corrected master obtained by the alignment means. A second master check filter section that checks the pattern state of data; a second AND gate section that takes the logical sum of the outputs of both filter sections; 1. A printed wiring board inspection device comprising: a defect aggregation unit that aggregates defect data of missing parts obtained by a gate unit.