JP2000241130A - Method and apparatus for inspecting pattern - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and apparatus for inspecting patterns which is capable of inspecting wiring patterns different in line width, shape and size, permits an allowance to be set every wiring, and inspecting at a high precision. SOLUTION: A means 44 is provided for comparing a fatal region pattern 34 which is generated from design data for forming a wiring pattern and shows necessary indispensable regions corresponding to the center of the wiring pattern with an inspected pattern obtained from wiring patterns on an object under test, thereby detecting the defect from the non-coincidence of both patterns. Thus, the fatal region pattern and the inspected pattern are compared to detect the defect from the non-coincidence of both patterns and hence the defect of the necessary indispensable regions corresponding to the center of the wiring pattern can be detected at a high precision.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pattern inspection method and apparatus, and more particularly, to a pattern inspection method and apparatus for inspecting a pattern of a printed wiring board. 2. Description of the Related Art In recent years, with the increase in the density of electronic devices, the development of multilayer thin film patterns for printed wiring boards inside electronic devices for high-density wiring has become active. In this manufacturing process, it is essential to inspect the wiring pattern for chipping or disconnection or short circuit. Since the wiring patterns are becoming finer and finer, it is no longer possible for this inspection to be visually observed by an operator. Therefore, an automatic visual inspection device is used.

[0002]

2. Description of the Related Art In a conventional technique for automatically inspecting a wiring pattern for defects, the wiring pattern is optically read and converted into an electric signal. Generally, a binarized image is obtained here. Then, a defect is detected from the obtained image. As a conventional technique, Japanese Patent Application Laid-Open No. 62-263 proposed by the present applicant has been proposed.
No. 404 (Japanese Patent Application No. 61-107407). FIG. 1 shows a block diagram of the conventional pattern inspection apparatus. In the figure, the printed wiring board 1 to be inspected
Is imaged by the CCD camera 2, and the obtained analog image signal is binarized by the binarization circuit 3 and stored in the storage circuit 4. The length measuring circuit 5 measures the length of the pattern in each direction using a radial length measuring sensor, and checks whether or not the pattern is at the center of the pattern (center detection 6). The radial coding circuit 7 converts the value of the pattern length in a plurality of directions into a 16-bit code called a "radial code" for the central one. The defect (normal or defective) is determined by associating the defect dictionary 8 in which the quality of each radial code is stored in advance with the detected radial code. This method has versatility that can be applied to various patterns because the dictionary data can be exchanged.

Further, as an improvement of the above invention, there is an apparatus disclosed in Japanese Patent Application Laid-Open No. 5-264240 proposed by the present applicant. FIG. 2 shows a block diagram of the conventional pattern inspection apparatus. In the figure, the same parts as those in FIG. 1 are denoted by the same reference numerals. In FIG. 2, the process is the same as that of FIG. 1 until the defect dictionary 8 in which the quality of each radial code is stored in advance and the detected radial codes are associated with each other to determine the quality (normal or defect candidate).

Thereafter, the category conversion circuit 10 converts each radial code into a category code representing a category (for example, copper residue or protrusion), and a category map conversion circuit 11 centers on the category of the defect candidate and distributes the surrounding category distribution. And using the pass / fail decision rule dictionary 12 to decide pass / fail and the type of defect on a global basis. FIG. 3 shows a flowchart of processing performed by the category map conversion circuit 11, the pass / fail judgment rule dictionary 12, and the comparison circuit 14. Step S1
Then, a category code is supplied from the category conversion circuit 10 to create a category map representing the distribution of categories. Next, in step S2, it is determined whether or not a category that matches the input category is present in the acceptability dictionary 12. For example, if the input category is "copper remaining" in the acceptability dictionary 12, a specific process is performed in step S3. The appropriate search method is read from the search method dictionary 13. When copper remains, the search method is, for example, “two-sided search”.

Next, in step S4, a two-sided search is performed centering on the copper residue on the category map.
In step 5, the comparison circuit 14 determines whether or not the search category (straight lead, land, etc.) has been searched, and determines whether the search category is normal (isolated copper remaining).
Alternatively, a determination such as abnormality (residual copper) is performed, and the determination result is output. For example, with respect to the printed wiring board 20 shown in FIG. 4A, the pass / fail judgment of the remaining coppers 1, 2, and 3 shown in FIGS. 4B, 4C, and 4D is performed as follows. A search method and a pass / fail rule are used. The search method is
As shown in FIG. 5, a search method is used for checking whether a specified category Y exists in both a certain direction A and a direction B 180 degrees different from the direction A, centering on a certain category X.

The pass / fail judgment rule uses this search method to center on the copper remaining category, and if there is a defective spacing category on both sides, "copper remaining defect", the defective spacing category exists on only one side, or exists on both sides. If not, use the pass / fail judgment rule of “normal copper remaining j.” Specifically, in the case of copper remaining 1 in FIG. 4B, since there is no category of defective spacing on both sides of copper remaining 1, “normal” Copper residue "can be determined. In the case of the remaining copper 2 in FIG. 4C, the category of the poor spacing exists only on one side of the remaining copper 2, so that
It can be determined that "normal copper remains".

In the case of copper remaining 3 in FIG. 4 (D), since there is a category of poor spacing on both sides, it becomes a “copper remaining defect”, and the quality and type can be determined. According to this method, by converting a radial code into a category, pass / fail can be determined globally, and a pass / fail result can be output including the type of defect. In addition, an inspection method using design data (CAD bitmap) has been proposed. C
In the check logic of the AD bitmap reference type, basically, C
The AD bitmap is regarded as a normal (ideal) wiring pattern having no defect, and a difference (difference) from the pattern to be inspected is extracted, and the difference is determined as a defect, or the obtained difference is determined. In addition, an inspection is performed to determine whether a defect is highly classified as normal.

As another prior art, there is an apparatus described in Japanese Patent Application Laid-Open No. 3-163845 proposed by the present applicant. In this conventional technique, an inspection reference pattern is created by moving a pattern based on design data in each of the X direction, the Y direction, and the θ direction, and an allowable range is set. Inspection is performed by collating inclusive relations.

[0009]

In the conventional inspection apparatus for performing radial matching shown in FIGS. 1 and 2, an allowable range (a range to be determined as a normal read) for one type of lead pattern is determined by an inspection standard. Was set. For example, FIG.
When there is a lead pattern as shown in FIG.
From b and c, respectively, it is determined as normal, thin, and fat.
On the contrary, the conventional inspection apparatus can set only one kind of line width allowable range and cannot cope with a plurality of line widths.

For example, consider the case of a normal wiring pattern having a plurality of line widths as shown in FIG. For example, when an allowable range is set for this pattern with reference to the linear lead 2, the linear lead 1 is determined to be thin and the linear lead 2 is determined to be thick. However, originally, all of them are normal linear leads, so that an erroneous determination is made. When the allowable range is set based on the straight lead 1,
Both straight leads 2 and 3 become thicker, and when straight lead 3 is used as a reference, both straight leads 1 and 2 become tighter,
In each case, an erroneous determination is made. In addition, since a plurality of allowable values cannot be set for lands having various sizes, the same problem as described above occurs. Further, even if a plurality of line widths can be set, if it is desired to set a different allowable range for each line width and land, there is a problem that it is difficult to know which allowable value should be set for which wiring. Was.

The conventional inspection apparatus for performing radial matching shown in FIGS. 1 and 2 cannot measure a length exceeding the size of the length measurement sensor shown in FIG. Therefore, the length measurement sensor must be set to a size suitable for the wiring pattern. However, in a printed wiring board having a plurality of line widths or a large land (pat), the length measuring sensor must be set as large as possible. However, as the size of the length measuring sensor increases, the distance between the sensors shown in FIG. 8 increases, and the shape cannot be recognized correctly. Further, as a practical problem, if the size of the length measuring sensor is too large, a circuit scale of a register or the like becomes large, and a problem that processing time is required occurs.

In an inspection method using design data (CAD bitmap), an allowable value cannot be set for each wiring. Therefore, for example, the allowable value is set uniformly,
There is a method of judging pass / fail from the magnitude of a difference (difference) between the CAD pattern and the inspection pattern. That time,
For example, when there are inspection patterns 1 and 2 having the same narrow width with respect to the CAD pattern as shown in FIG. 9, the difference between the inspection pattern 1 and the CAD pattern is 2 between d1 and d2.
And the size of each of d1 and d2 is smaller than the allowable value and is determined to be normal.
The difference from the pattern is that one d3 occurs and d3 (= d
The size of (1 + d2) is considerably larger than that of the inspection pattern 1 and exceeds the allowable value, so that the defect is determined. As described above, there is a problem that different results are generated for one allowable value, and the reliability of the determination is reduced.

Further, a pattern based on the design data is represented by X
In the case of applying a method of creating an inspection reference pattern by moving in each of the direction, the Y direction, and the θ direction and collating the inclusive relation with the pattern to be inspected, for example, an image of a printed wiring board shown in FIG. In order to shift the whole, all of the linear leads 1, 2, and 3 have the same allowable value. Therefore, it is impossible to inspect a plurality of line widths. In addition, since the mask data is only enlarged in the designated direction (X, Y, θ), as shown in FIG. 9, even if the thin line width is the same defect, the inspection pattern 2 is determined to be a defect. Although it is possible, there is a problem that the test pattern 1 is erroneously determined to be normal.

The present invention has been made in view of the above points, and can perform a pattern inspection for each of wiring patterns having different line widths, shapes, and sizes, and can set an allowable value for each wiring. An object of the present invention is to provide a pattern inspection method and an apparatus thereof that enable highly accurate inspection.

[0015]

According to the first aspect of the present invention, a wiring pattern having a plurality of wirings having different line widths and a plurality of lands having different shapes and sizes formed on an object to be inspected is generated. In a pattern inspection apparatus for detecting and inspecting a defect, a critical area pattern generated from design data for forming the wiring pattern and indicating an indispensable area corresponding to a central portion of the wiring pattern; A comparison unit is provided for comparing a test pattern obtained from the upper wiring pattern and detecting a defect due to a mismatch between the two patterns.

As described above, since the critical area pattern and the inspection pattern are compared with each other to detect a defect due to a mismatch between the two patterns, even a large wiring pattern must correspond to the center of the wiring pattern. Can detect defects in various areas with high accuracy. According to a second aspect of the present invention, in the pattern inspection apparatus according to the first aspect, a large pattern conversion pattern generated from the design data and corresponding to a central portion of the wiring pattern and a wiring pattern on the inspection object are provided. Calculating the obtained inspection pattern, a peripheral pattern creating means for extracting a peripheral pattern from which the central part of the inspection pattern is deleted, and measuring the line width of the peripheral pattern to determine that the line width is an allowable value. And length measuring means for detecting a defect when the defect is out of the range.

As described above, since the line width of the peripheral pattern from which the center portion of the inspection pattern is deleted is measured and a defect is detected when the line width is out of the allowable range, a large wiring pattern is used. Also, the defect of the peripheral pattern of the wiring pattern can be detected with high accuracy. According to a third aspect of the present invention, there is provided a pattern inspection method for detecting and inspecting a defect generated in a wiring pattern formed on an inspection object and having a plurality of wirings having different line widths and a plurality of lands having different shapes. Comparing a critical area pattern generated from design data for forming the wiring pattern and indicating an indispensable area corresponding to the center of the wiring pattern with an inspection pattern obtained from the wiring pattern on the inspection object. Then, a defect is detected by a mismatch between the two patterns.

As described above, the critical area pattern and the inspection pattern are compared to detect a defect due to a mismatch between the two patterns. Therefore, even if the wiring pattern is a large wiring pattern, it is indispensable to correspond to the center of the wiring pattern. Can detect defects in various areas with high accuracy. According to a fourth aspect of the present invention, in the pattern inspection method according to the third aspect, a large pattern conversion pattern generated from the design data and corresponding to a central portion of the wiring pattern and a wiring pattern on the inspection object are provided. By calculating the obtained inspection pattern, the peripheral pattern from which the center part of the inspection pattern is deleted is taken out, and the line width of the peripheral pattern is measured. When the line width is out of the allowable range, the defect is detected. Is detected.

As described above, since the line width of the peripheral pattern from which the center portion of the inspection pattern is deleted is measured and a defect is detected when the line width is out of the allowable range, a large wiring pattern is used. Also, the defect of the peripheral pattern of the wiring pattern can be detected with high accuracy. According to a fifth aspect of the present invention, there is provided the pattern inspection method according to the fourth aspect, further comprising an allowable value pattern generated from the design data and registering at least an allowable value for each address of the wiring pattern. A range of allowable values is obtained from the allowable value pattern.

As described above, in order to obtain the allowable value range for the line width from the allowable value pattern in which the allowable value is registered for each address of the wiring pattern, the allowable value range can be varied for each wiring pattern. The invention according to claim 6 is
5. The pattern inspection method according to claim 3, wherein the critical area pattern reduces a wiring pattern generated from the design data by a difference allowable amount that is a total value of a positional deviation allowable amount and a chipping allowable amount. The portion below the difference allowable amount is created leaving one pixel.

As described above, the wiring pattern is reduced by the difference allowable amount which is the total value of the positional deviation allowable amount and the chipping allowable amount,
A fatal area pattern can be created by leaving one pixel for the portion equal to or less than the difference allowable amount.
According to a seventh aspect of the present invention, in the pattern inspection method according to the sixth aspect, the large pattern conversion pattern is created by reducing the critical area pattern by a predetermined number of pixels.

As described above, by reducing the critical area pattern by a predetermined number of pixels, a large pattern conversion pattern can be created. According to an eighth aspect of the present invention, in the pattern inspection method according to the fourth aspect, the line width of the peripheral portion pattern is measured by performing a radial length measurement of the peripheral portion pattern, and the minimum measured value is determined by the line width. And

As described above, by performing the radial measurement and setting the minimum measured value to the line width, the line width of the peripheral pattern can be measured.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, an allowable range is set for each wiring. Normally, a CAD bitmap that is design data is stored as bitmap image data by:
Since the capacity is large, the data is stored in vector format data. The vector data is composed of a development instruction describing a start point and an end point, an aperture, and an aperture list describing details of the aperture.

FIGS. 10A and 10B show examples of vector data. In the aperture list shown in FIG. 10A, a code indicating the type of the aperture, dimensions, and
A type indicating what the aperture corresponds to on the actual wiring is described. For example, in the case of A01, a lead is drawn with a circular aperture having a diameter of 100 μm. In the case of B02, one side of the square is 500 μm.
The land is drawn with the aperture of m. FIG.
In the expansion instruction shown in (B), a start point, an end point, and an aperture are described. FIG. 11 shows a CAD bit map developed according to the vector data.

In the present invention, as shown in FIG.
A permissible value is added for each wiring to an aperture list in which codes, types, and dimensions of respective parts (parts) are written. The data of the aperture list and the vector data composed of the expansion instruction shown in FIG. Using this, an allowable value pattern shown in FIG. 12C is created. In addition, in the allowable value pattern, a value of the minimum conductor interval or the like is set in advance in a place other than the wiring part (base part = air space part) on the CAD pattern shown in FIG.

The conventional normal CAD bit map is binary data (pattern signal) indicating whether or not a wiring is provided for each address. In the present invention, as shown in FIG. In addition to the pattern signal,
Type, size, allowable range, etc. are added to form multi-value data, which is used as an allowable value pattern. Next, a critical region pattern created by the present invention will be described. When a CAD bitmap is created from vector data, the CAD bitmap is reduced by the difference allowable amount, which is the total value of the positional deviation allowable amount and the chipping allowable length in the large pattern, and the wiring pattern (in this case, A critical area pattern indicating an indispensable area corresponding to the center of the land is created. More specifically, a CAD bitmap shown in FIG. 13A is created, and the CAD bitmap is reduced by an allowable amount of displacement to obtain a pattern shown in FIG. 13B. FIG.
A critical area pattern shown in FIG. 13C is obtained by reducing the CAD bitmap shown in FIG.

However, when the image is reduced, a pattern having an allowable difference in width is erased. In this case, a thinning process is performed in which at least one pixel is left. Further, when creating a critical area pattern, the above-mentioned difference allowable amount is added as a dimension after conversion to an allowable value pattern. The dimension after conversion is used as a reference value at the time of determination by the radial length measuring unit.

In FIGS. 13A, 13B and 13C, as an example, the allowable displacement is 50 μm and the allowable difference is 25.
It is 0 μm. This numerical value indicates that when the resolution is 10 μm and the minimum line width is 100 μm (10 pixels), the positional deviation is ± 50 μm, assuming that the alignment accuracy can be adjusted with a deviation amount within one line width. (5 pixels). The allowable value of the chip defect of the large pattern was set to 200 μm (20 pixels). The region of the critical region pattern created in this way must exist on a normal inspection pattern. This is because the pattern is created in consideration of the difference allowable tatami mat. When an AND operation is performed on a normal pattern and a critical region pattern (the pattern portion is set to a value of 1 and the other base portions are set to 0), the value is 1 if the pattern is normal and 0 if the pattern is normal.

The test pattern P1 shown in FIG.
There are missing parts K1 and K2. An AND operation is performed on this and a critical area pattern P2 indicated by a satin finish in FIG. In this case, as shown in FIG. 14B, the displacement between the inspection pattern P1 and the critical area pattern P2 is within the allowable range (within 50 μm) indicated by the hatched portion. At this time,
The large chip K2 overlaps with the critical area pattern P2 and is a defect because it invades it, and the small chip K1 does not overlap with the critical area pattern P2 and is not a defect because it does not invade it.

Next, a description will be given of a large pattern conversion pattern created by the present invention. By reducing the critical area pattern P2 as shown in FIG. 15A by a predetermined number of pixels (for example, one pixel), a large pattern conversion pattern as shown in FIG. A pattern P3 is created. In other words, the pattern of one pixel in the lead wiring portion of the fatal region pattern P2 is deleted, and the large pattern conversion pattern P3 is a pattern of only a large pattern corresponding to a land.

FIG. 16 collectively shows the creation of the critical area pattern and the large pattern conversion pattern. In the figure,
A permissible displacement amount is added to the CAD bitmap 22 and expanded, and the critical area pattern 24 is obtained by performing a reduction process by the permissible difference amount. Further, by reducing this by one pixel, a large pattern conversion pattern 25 is created. FIG. 17 is a block diagram showing an embodiment of the pattern inspection apparatus according to the present invention. In the figure, the storage unit 30 stores an allowable value pattern as shown in FIG. 12C created from CAD data. Further, the storage unit 32 stores a large pattern conversion pattern as shown in FIG. 15B created from the CAD data.
A critical area pattern as shown in FIG. 13C created from the D data is stored. In each of the above-mentioned allowable value pattern, large pattern conversion pattern, and critical area pattern, the pattern portion has a value of 1 and the other portions have a value of 0.
And

The inspection image of the inspection target printed wiring board or the like captured by the CCD camera or the like of the optical system 36 is temporarily stored in the storage unit 3.
8 is stored. The image data of the inspection image read therefrom is binarized by the pre-processing unit 40 (the pattern portion is set to the value 1,
After the other substrate portion is set to a value of 0), it is supplied to the alignment unit 42. The alignment unit 42 aligns the allowable value pattern read from the storage unit 30 with the inspection pattern of the binarized data of the inspection image. The inspection pattern aligned with the tolerance pattern
It is supplied to the comparison operation unit 44 and the operation unit 46.

The comparison operation unit 44 performs an AND operation on the inspection pattern and the critical area pattern read from the storage unit 32, and as shown in FIG. If there is a portion that does not overlap with the fatal area, it is determined that there is a defect, and the determination result is output as a pass / fail result output unit 5.
Supply 0. The operation unit 46 performs an exclusive OR operation on the inspection pattern and the large-size pattern conversion pattern read from the storage unit 32. For example, FIG.
18B, the portion corresponding to the large pattern conversion pattern is cut out and deleted, and an EXOR pattern as a peripheral pattern in which the center portion of the test pattern is deleted as shown in FIG. , Radial measuring unit 4
8

Next, the determination method in the radial length measuring section 48 will be described. When attempting to measure a large inspection pattern using a length measurement sensor of a predetermined size, FIG.
As shown in (1), the length of the inspection pattern cannot be measured because the length measurement sensor 60 does not intersect with the contour of the large inspection pattern. Therefore, the large measurement pattern is measured by the length measurement sensor 60 by performing an exclusive OR operation with the large pattern conversion pattern (included in the critical region pattern, and the critical region pattern is inspected by the comparison operation unit 44). Convert to a possible EXOR pattern.

As a result, as shown in FIG.
The unmeasured area can be measured by the length measuring sensor 60.
The length measuring sensor 60 has eight directions from the center in the diametric direction,
It is arranged in 2.5 degree steps, and a realistic size is 64, for example.
The length is equal to the length of a pixel (640 μm). The length measuring sensor shown in FIG. 18 is simplified in drawing to have four directions.
The length measurement is performed only on the pixels for which the symmetry is recognized, and the minimum length measurement value among the lengths in the eight measured directions is defined as the line width.

When the length measurement value for each pixel on the scanning trajectory indicated by the solid line 62 in FIG. 18C is obtained, the radial measurement unit 48 reads each pixel on the scanning trajectory read from the storage unit 30. Is compared with the allowable value pattern of the pixel corresponding to. If it is within the allowable range, it is determined to be normal, and if it is not within the allowable range, it is determined to be defective, and the determination result is supplied to the pass / fail result output unit 50.

For example, the EXOR pattern 7 shown in FIG.
It is assumed that the length measurement is performed for 0 and the address of the missing portion 72 of the EXOR pattern 70 is (530, 150). At this time, the shortest measured value is the line width, which is 18
It was 0 μm. Here, referring to the address (530, 150) of the allowable value pattern, the dimension after conversion, which is the design width, is 250 μm, and the allowable value is ± 100 μm.

For this reason, if the line width is 150 to 350 μm, it is determined to be normal. However, as shown in FIG. 19, since the shortest measured value is 180 μm, this missing portion 72 is determined to be normal. . The comparing means described in the claims corresponds to the comparison calculating section 44, the peripheral pattern creating means corresponds to the calculating section 46, and the length measuring means corresponds to the radial length measuring section 48.

[0040]

As described above, the first aspect of the present invention provides
A critical area pattern generated from design data for forming a wiring pattern and indicating an indispensable area corresponding to the center of the wiring pattern is compared with an inspection pattern obtained from the wiring pattern on the inspection object. And comparing means for detecting a defect due to a mismatch between the two patterns.

As described above, the critical area pattern and the inspection pattern are compared with each other to detect a defect based on a mismatch between the two patterns. Therefore, even if the wiring pattern is large, it is indispensable to correspond to the center of the wiring pattern. Can detect defects in various areas with high accuracy. The invention according to claim 2 calculates a large pattern conversion pattern generated from design data and corresponding to a central portion of the wiring pattern, and an inspection pattern obtained from the wiring pattern on the inspection object, and A peripheral pattern creating means for extracting a peripheral pattern from which a central portion of the inspection pattern is deleted; and a length measuring unit for measuring a line width of the peripheral pattern and detecting a defect when the line width is outside a range of an allowable value. Means.

As described above, since the line width of the peripheral pattern from which the center portion of the inspection pattern is deleted is measured and a defect is detected when the line width is out of the allowable range, a large wiring pattern is used. Also, the defect of the peripheral pattern of the wiring pattern can be detected with high accuracy. According to a third aspect of the present invention, there is provided a critical area pattern generated from design data for forming a wiring pattern and indicating an indispensable area corresponding to a central portion of the wiring pattern, and a wiring on the inspection object. A defect is detected by comparing the inspection pattern obtained from the pattern with a mismatch between the two patterns.

As described above, the critical area pattern and the inspection pattern are compared with each other to detect a defect due to a mismatch between the two patterns. Therefore, even if the wiring pattern is large, it is indispensable to correspond to the center of the wiring pattern. Can detect defects in various areas with high accuracy. The invention according to claim 4, wherein a large pattern conversion pattern corresponding to the center of the wiring pattern generated from design data and an inspection pattern obtained from the wiring pattern on the inspection object are calculated, and The peripheral pattern from which the central part of the inspection pattern is deleted is taken out, and the line width of the peripheral pattern is measured. When the line width is out of the allowable range, a defect is detected.

As described above, since the line width of the peripheral pattern from which the center portion of the inspection pattern is deleted is measured and a defect is detected when the line width is out of the allowable range, a large wiring pattern is used. Also, the defect of the peripheral pattern of the wiring pattern can be detected with high accuracy. The invention according to claim 5 has an allowable value pattern generated from design data and at least an allowable value registered for each address of the wiring pattern, and a range of allowable values for the line width is obtained from the allowable value pattern. .

As described above, in order to obtain the allowable value range for the line width from the allowable value pattern in which the allowable value is registered for each address of the wiring pattern, the allowable value range can be varied for each wiring pattern. In the invention according to claim 6, the critical area pattern reduces a wiring pattern generated from the design data by a difference allowable amount that is a total value of a positional deviation allowable amount and a chipping allowable amount, and is equal to or smaller than the difference allowable amount. Is created except for one pixel. In this manner, the critical area pattern is created by reducing the wiring pattern by the difference allowance, which is the total value of the positional shift allowance and the chipping allowance, and leaving one pixel for the portion below the difference allowance. be able to.

According to the seventh aspect of the present invention, the large pattern conversion pattern is created by reducing the critical area pattern by a predetermined number of pixels. In this way, by reducing the critical area pattern by a predetermined number of pixels, a large pattern conversion pattern can be created. In the invention according to claim 8, in measuring the line width of the peripheral portion pattern, the radial length of the peripheral portion pattern is measured, and the minimum measured value is defined as the line width.

As described above, by performing the radial measurement and setting the minimum measured value to the line width, the line width of the peripheral pattern can be measured.

[Brief description of the drawings]

FIG. 1 is a block diagram of a conventional pattern inspection apparatus.

FIG. 2 is a block diagram of a conventional pattern inspection apparatus.

FIG. 3 is a flowchart of processing performed by a category map conversion circuit, a pass / fail judgment rule dictionary, and a comparison circuit of FIG. 2;

FIG. 4 is a diagram for explaining quality judgment of a printed wiring board;

FIG. 5 is a diagram for explaining a search method.

FIG. 6 is a diagram showing a lead pattern.

FIG. 7 is a diagram showing a normal wiring pattern in which a plurality of line widths are mixed.

FIG. 8 is a diagram showing a length measuring sensor.

FIG. 9 is a diagram showing inspection patterns having the same narrow width.

FIG. 10 is a diagram illustrating an example of vector data.

FIG. 11 shows a CA developed from the vector data of FIG.
It is a figure showing a D bitmap.

FIG. 12 is a diagram showing an embodiment of the vector data of the present invention.

FIG. 13 is a diagram for explaining creation of a critical area pattern.

FIG. 14 is a diagram for explaining a defect in a critical area.

FIG. 15 is a diagram for explaining creation of a large pattern conversion pattern.

FIG. 16 is a diagram collectively showing creation of a critical area pattern and a large pattern conversion pattern.

FIG. 17 is a block diagram of an embodiment of the pattern inspection apparatus of the present invention.

FIG. 18 is a diagram illustrating a pattern inspection according to the present invention.

FIG. 19 is a diagram for explaining radial measurement of an EXOR pattern.

[Explanation of symbols]

 30, 32, 34, 38 storage unit 36 optical system 40 preprocessing unit 42 positioning unit 44 comparison operation unit 46 operation unit 50 pass / fail result output unit 60 length measurement sensor

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) H05K 3/00 G06F 15/62 405A 15/70 455A F term (Reference) 2F065 AA22 AA49 BB02 CC01 DD00 DD06 DD07 FF02 FF04 FF61 HH15 JJ03 JJ09 JJ26 QQ00 QQ04 QQ21 QQ23 QQ24 QQ25 QQ31 QQ32 QQ37 QQ47 RR05 RR08 2F069 AA49 AA60 BB14 CC06 DD08 DD15 DD16 GG04 GG07 GG72 NN08 2G05 EA01ED02 EC05 EA01 EA01 EA04 EA04 BA02 CA02 CA06 CA12 CA16 DA03 DB02 DB05 DB08 DC03 DC08 DC33 5L096 AA03 AA07 BA03 BA18 CA02 CA14 FA17 FA62 FA64 FA67 GA24 HA07 JA09

Claims (8)

[Claims] 1. A pattern inspection apparatus for detecting and inspecting a defect formed in a wiring pattern formed on an object to be inspected and having a plurality of wirings having different line widths and a plurality of lands having different shapes and sizes. A critical area pattern generated from design data for forming the wiring pattern and indicating an indispensable area corresponding to the center of the wiring pattern is compared with an inspection pattern obtained from the wiring pattern on the inspection object. A pattern inspection apparatus comprising: a critical area pattern indicating an indispensable area for detecting a defect due to a mismatch between the two patterns; and a wiring pattern comparing means on the inspection object. 2. The pattern inspection apparatus according to claim 1, wherein a large pattern conversion pattern generated from the design data and corresponding to a central portion of the wiring pattern, and an inspection pattern obtained from the wiring pattern on the inspection object. And a peripheral pattern creating means for extracting a peripheral pattern from which the central part of the inspection pattern is deleted, and measuring a line width of the peripheral pattern and the line width is out of a range of an allowable value. And a length measuring means for detecting a defect. 3. A pattern inspection method for detecting and inspecting a defect generated in a wiring pattern formed on an inspection object and having a plurality of wirings having different line widths and a plurality of lands having different shapes, wherein the wiring pattern is provided. A critical area pattern generated from the design data for forming a critical area corresponding to the central portion of the wiring pattern and an inspection pattern obtained from the wiring pattern on the inspection object is compared. A pattern inspection method characterized by detecting a defect based on a pattern mismatch. 4. The pattern inspection method according to claim 3, wherein a large pattern conversion pattern generated from the design data and corresponding to a central portion of the wiring pattern, and an inspection pattern obtained from the wiring pattern on the object to be inspected. Calculating the peripheral pattern from which the central part of the inspection pattern is deleted, measuring the line width of the peripheral pattern, and detecting a defect when the line width is out of the allowable range. A pattern inspection method characterized by the following. 5. The pattern inspection method according to claim 4, further comprising an allowable value pattern generated from the design data and registering at least an allowable value for each address of the wiring pattern, and an allowable value range for the line width. From the allowable value pattern. 6. The pattern inspection method according to claim 3, wherein the critical area pattern is a difference allowable amount that is a total value of a positional deviation allowable amount and a chipping allowable amount of a wiring pattern generated from the design data. A pattern inspection method wherein a portion smaller than the allowable difference amount is created while leaving one pixel. 7. The pattern inspection method according to claim 6, wherein the large pattern conversion pattern is created by reducing the critical area pattern by a predetermined number of pixels. 8. The pattern inspection method according to claim 4, wherein the line width of the peripheral edge pattern is measured by radially measuring the peripheral edge pattern, and a minimum length measurement value is set to the line width. Characteristic pattern inspection method.