JP2007149837A - Device, system, and method for inspecting image defect - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce pseudo defects caused by color unevenness that occurs in an image to be inspected, relating to image defect inspection for comparing the image to be inspected of an object with a reference image that should be identical with the image to be inspected, for detecting a different part as a defect. <P>SOLUTION: The image defect inspection device comprises a reference value determining part 21 in which a reference value is determined according to the value of a pixel contained for each image of each region having a specified dimension in an object, and a distribution information determining part 22 for determining the distribution information of a reference value decided for each region of the specified dimension contained in the macro region. A defect is detected by changing a defect detection condition according to the distribution information calculated in the macro region. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an image defect inspection apparatus, an image defect inspection system, and an image for comparing an inspection image obtained by imaging an inspection object with a reference image that should be essentially the same as the inspection image and detecting different portions as defects. The present invention relates to a defect inspection method. In particular, in order to detect defects in the semiconductor circuit pattern formed on the semiconductor wafer in the semiconductor manufacturing process, the surface of the semiconductor circuit wafer is imaged, and the captured image and the reference image are compared. The present invention relates to an image defect inspection apparatus, an image defect inspection system, and an image defect inspection method.

  The present invention relates to an image defect inspection apparatus, an image defect inspection system, and an image for comparing an inspection image obtained by imaging an inspection object with a reference image that should be essentially the same as the inspection image and detecting different portions as defects. For defect inspection methods. Here, an example of an appearance inspection apparatus (inspection machine) that detects defects in a semiconductor circuit pattern formed on a semiconductor wafer in a semiconductor manufacturing process will be described, but the present invention is not limited to this.

  A general appearance inspection apparatus is a bright field inspection apparatus that illuminates a target surface from the vertical direction and captures an image of reflected light, but a dark field inspection apparatus that does not directly capture illumination light is also used. In the case of a dark field inspection apparatus, a sensor is arranged so that regular reflection is not detected by illuminating the target surface from an oblique direction or a vertical direction, and a dark field image of the target surface is obtained by sequentially scanning the irradiation position of the illumination light. . Therefore, the image sensor may not be used in the dark field device, but this is also an object of the invention. In this way, the present invention compares any corresponding part of two images (signals) that should be the same, and any method and apparatus as long as it is an image processing method and apparatus that determines a part having a large difference as a defect. It is also applicable to the device.

  In the semiconductor manufacturing process, a large number of chips (dies) are formed on a semiconductor wafer. Each die is patterned over several layers. The completed die is electrically inspected by a prober and tester, and the defective die is removed from the assembly process. In the semiconductor manufacturing process, the yield is very important, and the result of the electrical inspection is fed back to the manufacturing process and used for managing each process. However, the semiconductor manufacturing process is formed in many processes, and it takes a very long time from the start of manufacturing until the electrical inspection is performed. At this time, a large number of wafers are already being processed, and the inspection results cannot be fully utilized for improving the yield. Therefore, pattern defect inspection is performed in which a pattern formed in an intermediate process is inspected to detect a defect. If pattern defect inspection is performed in a plurality of processes among all processes, defects generated after the previous inspection can be detected, and the inspection result can be quickly reflected in the process management.

  FIG. 1 shows a block diagram of an appearance inspection apparatus proposed by the applicant of the present patent application in Japanese Patent Application No. 2003-188209 (the following Patent Document 1). As shown in the figure, a sample stage (chuck stage) 2 is provided on the upper surface of a stage 1 that can move freely in two-dimensional or three-dimensional directions. On this sample stage, the semiconductor wafer 3 to be inspected is placed and fixed. An imaging device 4 configured using a one-dimensional or two-dimensional CCD camera or the like is provided above the stage, and the imaging device 4 generates an image signal of a pattern formed on the semiconductor wafer 3.

  As shown in FIG. 2, a plurality of dies 3a are repeatedly arranged in a matrix on the semiconductor wafer 3 in the X direction and the Y direction, respectively. Since the same pattern is formed on each die, it is common to compare images of corresponding portions of adjacent dies. If there is no defect on both dies, the gray level difference is small, and if there is a defect on one die, the gray level difference is larger than the threshold value. Therefore, the defect is detected by comparing this gray level difference with a predetermined detection threshold value (single detection). ) Since this does not know which die is defective, it is further compared with adjacent dies on different sides, and if the difference in gray level of the same part becomes larger than the threshold, it can be seen that the die is defective (double Detection).

  The imaging device 4 includes a one-dimensional CCD camera realized by a TDI imaging device or the like, and the stage 1 so that the camera moves (scans) relative to the semiconductor wafer 3 at a constant speed in the X direction or the Y direction. To move. An image obtained by imaging a band-like region (referred to as swath) having the same width as the imaging width Ws of the imaging device 4 indicated by a dotted line in FIG. 3A by scanning in the main scanning direction once A signal 80 is output from the imaging device 4, and the image signal is converted into a multi-value digital signal (gray level signal) and stored in the image storage unit 5.

  Thereafter, scanning is continued, and when a gray level signal (inspection image signal) is generated from the die 3a to the adjacent die 3b, the difference detecting unit 6 makes the adjacent two as shown in FIG. Gray level signals (reference image signals) of small partial images 81 and 82 (referred to as logical frames) of the same part of each of the dies 3 a and 3 b are read from the image storage unit 5 and input to the difference detection unit 6. Actually, a minute alignment process is performed, but detailed description is omitted here.

  The difference detection unit 6 receives gray level signals of partial images 81 and 82 of the same part of two adjacent dies 3a and 3b, one of which is an inspection partial image and the other as a reference image, and corresponding pixels. The difference between the gray level signals (gray level difference) between them is calculated and output to the detection threshold value calculation unit 7 and the defect detection unit 8. The detection threshold calculation unit 7 automatically determines a detection threshold according to the distribution of the gray level difference and outputs the detection threshold to the defect detection unit 8. The defect detection unit 8 compares the gray level difference with the determined threshold value and determines whether or not the defect is present. Then, the defect detection unit 8 determines, for each defect, the position of the defect, the gray level difference, a detection threshold value at the time of detection, a defect detection parameter used when determining the detection threshold value, and the like. The defect information including is output.

Thereafter, the defect information is provided to an automatic defect classification (ADC) device (not shown) in order to examine the portion determined to be a defect in more detail. In the automatic defect classification device, the portion determined to be a defect is a true defect that affects the yield, is a false defect that is falsely detected due to the influence of noise in the captured image, or any type of defect Defect classification processing is performed to determine whether it is a wiring short, pattern defect, particle, or the like.
This defect classification process requires a long processing time because it is necessary to examine the defect portion in detail. Therefore, when determining a defect, it is required that a true defect is not leaked and that other than the true defect is not determined as a defect as much as possible.

  Therefore, the threshold setting is a big problem. If the threshold value is reduced, the number of pixels (pixels) that are determined as defects increases, and even a portion that is not a true defect is determined as a defect. As a result, there is a problem that the time required for defect classification processing becomes longer. On the other hand, if the threshold value is increased too much, it is determined that the true defect is not a defect, which causes a problem that the inspection becomes insufficient.

In the appearance inspection apparatus proposed by the applicant of the present patent application in Japanese Patent Application No. 2003-188209 (Patent Document 1 below), the detection threshold value calculation unit 7 calculates the gray level difference between corresponding pixels of the inspection partial image and the reference image. The detection threshold is determined according to the distribution of.
When the gray level difference signal of each pixel included in the two partial images 81 and 82 to be compared is input from the difference detection unit 6, the detection threshold calculation unit 7 generates a histogram as illustrated in FIG. create. Then, the cumulative frequency as shown in FIG. 4B is calculated, and the cumulative frequency has a linear relationship with the gray level difference under the assumption that the distribution of the gray level difference follows a predetermined distribution. The conversion cumulative frequency converted as described above is calculated (see FIG. 4C).

Thereafter, an approximate straight line of the conversion cumulative frequency is calculated, and a threshold value is determined according to a predetermined calculation method from a predetermined cumulative frequency value based on the calculated approximate straight line. For example, in the example of FIG. 4C, if the calculated slope of the approximate curve is a and the intercept of the approximate curve with respect to the vertical axis (that is, the cumulative frequency at which the gray level difference is 0) is b (the slope a and The intercept b may be referred to as a defect detection parameter), and the threshold value T is calculated by the following equation (1).
T = (P1-b + VOP) / a + HO (1)
Here, P1 is a cumulative frequency corresponding to a predetermined cumulative probability (p), and VOP and HO are predetermined sensitivity setting parameters.

JP 2004-177397 A JP-A-4-107946 Japanese Patent No. 2996263 Japanese Patent Laid-Open No. 2002-22421

In an actual inspection image obtained by imaging the surface of a semiconductor wafer, even if the inspection image is obtained by imaging a wafer formed by the same process in the same state, it may be an image with different brightness (gray level value) or within one wafer. However, so-called “color unevenness” may occur in which areas that should be imaged with the same lightness are imaged with different lightness.
When defect inspection is performed using an inspection image with color unevenness in this way, the gray level difference increases to a portion that is not originally a defect, and is detected as a defect, resulting in an increase in pseudo defects.

  However, in the case of color unevenness that occurs in a captured image on the surface of a semiconductor wafer, the change in brightness with respect to the difference in position on the wafer surface is moderate compared to the size of the logical frame that is the unit of the image for defect inspection. For this reason, even if the change in the gray level value in one logical frame is observed, the presence or absence of color unevenness cannot be detected.

  In view of the above problems, the present invention compares an inspection image obtained by imaging an inspection object with a reference image that should be essentially the same as the inspection image, and detects image defects that are different from each other. An object is to reduce pseudo defects caused by color unevenness generated in an inspection image.

  In order to achieve the above object, in the present invention, a reference value determined according to a pixel value of a pixel included in an image obtained by imaging each region is determined for each region of a predetermined size on the inspection target. For a macro area configured to include a plurality of areas of a predetermined size, distribution information of reference values determined for each area of the predetermined size included in the macro area is determined, and distribution determined in the macro area The defect detection is performed by changing the defect detection condition according to the information.

  Further, in the present invention, for each area of a predetermined size on the inspection object, a predetermined measurement value related to the inspection object is measured in each of these areas, and a reference value determined according to the measured predetermined measurement value is determined. And determining the distribution information of the reference value determined for each of the predetermined size areas included in the macro area for a macro area configured to include a plurality of areas of the predetermined size. The defect detection is performed by changing the defect detection condition in accordance with the distribution information determined in step (b).

For the reference value determined based on the pixel value acquired for each area of a predetermined size on the inspection object and the measurement value of the inspection object, distribution information in a macro area wider than this predetermined area is calculated. By doing so, it is possible to detect color unevenness that occurs in a wide range of a captured image obtained by imaging the inspection object.
Then, by performing defect detection by changing the defect detection condition according to the calculated distribution information, it becomes possible to reduce pseudo defects caused by color unevenness occurring in the inspection image.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 5 is a block diagram of a first embodiment of an image defect inspection apparatus for a semiconductor circuit according to the present invention. The image defect inspection apparatus 10 shown in FIG. 5 has a configuration similar to that of the conventional appearance inspection apparatus 10 described with reference to FIG. 1, and therefore, the same components are denoted by the same reference numerals. The description is omitted.

By moving the stage 1 on which the semiconductor wafer 3 to be inspected is moved, the image pickup apparatus 4 having a one-dimensional CCD camera realized by a TDI image pickup device or the like is moved in the X direction or the Y direction with respect to the semiconductor wafer 3. When the scanning is relatively performed at a constant speed, a single band-shaped scan having the same width as the imaging width Ws of the imaging device 4 as shown by a dotted line in FIG. An inspection image obtained by imaging the region is obtained, and this inspection image is converted into a multi-value digital signal (gray level signal) and then stored in the image storage unit 5.
Returning to FIG. 5, when scanning is continued as it is, a gray level signal (inspection image signal) is generated from the die 3a to the adjacent die 3b. The difference detection unit 6 is a gray level signal (reference image signal) of small partial images (logical frames) 81 and 82 of the same part of two adjacent dies 3a and 3b as shown in FIG. Is read from the image storage unit 5 and input to the difference detection unit 6.

  The difference detection unit 6 receives gray level signals of partial images 81 and 82 of the same part of two adjacent dies 3a and 3b, one of which is an inspection partial image and the other as a reference image, and corresponding pixels. The difference between the gray level signals (gray level difference) is calculated and output to the detection threshold value calculation unit 7 and the defect detection unit 8.

Here, the partial image 81 is cut out by dividing a strip-shaped inspection image 80 (soss) having a width Ws shown between regions sandwiched by dotted lines in FIG. Therefore, these partial images 81 form inspection partial images according to the claims of the present invention. The partial image 82 compared with the partial image 81 forms a reference image compared with the inspection partial image.
Further, since the partial image 81 is an image obtained by capturing the semiconductor wafer 3 to be inspected for each area having a predetermined size, the area having a predetermined size on the inspection object according to the claims of the present invention. An image obtained by imaging each of these areas is formed every time.
Further, since the partial image 81 is cut out by dividing the inspection image into predetermined sizes, these constitute image blocks according to the claims of the present invention.

  In the image defect inspection apparatus 10 according to the present embodiment, one of the two adjacent die logical frames is used as a reference image. However, instead of this, a sample of an ideal image of the wafer 3 captured in the past may be used as a reference image, and samples of the images of a plurality of wafers 3 are averaged for each pixel, for example. Sample (so-called “golden image”) may be used as a reference image, or ideally by simulation from design data (for example, CAD data) of a pattern formed on the surface of the semiconductor wafer 3 The created image may be used as a reference image.

The detection threshold calculation unit 7 automatically determines a detection threshold, which is a defect detection condition, according to the distribution of gray level differences, and outputs the detection threshold to the defect detection unit 8.
As described with reference to FIGS. 4A to 4C, the determination of the detection threshold by the detection threshold calculation unit 7 includes the two partial images 81 and 82 compared with the difference detection unit 6. The gray level difference signal of each pixel included in the image is input to create a histogram (see FIG. 4A), and the cumulative frequency is calculated (see FIG. 4B). Under the assumption that the gray level difference distribution follows a predetermined distribution, a converted cumulative frequency is calculated so that the cumulative frequency has a linear relationship with the gray level difference (see FIG. 4C). Thereafter, an approximate straight line of the converted cumulative frequency is calculated (that is, the slope a and the intercept b of the approximate curve as defect detection parameters are calculated), and a predetermined cumulative frequency value is calculated based on the calculated approximate straight line. Threshold value according to the predetermined calculation method as above Determined.

  The defect detection unit 8 compares the gray level difference with the determined threshold value and determines whether or not the defect is present. Then, the defect detection unit 8 outputs defect information including a defect position, a gray level difference, a detection threshold at detection, a defect detection parameter, and the like for each defect with respect to a portion determined to be a defect.

As shown in FIG. 6, the image defect inspection apparatus 10, for each partial image (logical frame) 81 that is also an image block obtained by dividing the inspection image 80 by a predetermined size, pixel values of pixels included in these partial images. Accordingly, a reference value determining unit 21 that determines reference values determined according to a predetermined determination method is provided.
For example, the reference value determination unit 21 may determine an average value, a variance value, a maximum value, or a minimum value of a plurality of pixels included in each partial image 81 that is an image block as a reference value. Alternatively, the reference value determination unit 21 may, for example, calculate an average value, a variance value, a maximum value, a minimum value, or an intermediate value or a difference between the maximum value and the minimum value of all pixels included in each partial image 81 as a reference value. May be defined as
The reference value determination unit 21 also calculates the average value, variance value, maximum value, minimum value of the pixel values of the pixels existing in a predetermined range in the partial image 81 among all the pixels included in each partial image 81 that is an image block. A value or an intermediate value or a difference between the maximum value and the minimum value may be determined as a reference value, and a pixel value of a pixel existing at a predetermined position in the partial image 81 may be determined as a reference value.
Further, the reference value determining unit 21 calculates the average value, the variance value, the maximum value, the minimum value, or all the pixels included in each partial image 81 and the difference image between the partial image 81 and the reference image to be compared in the difference detection unit 6. An intermediate value or a difference between the maximum value and the minimum value may be defined as a reference value, and an average value, a variance value, a maximum value, a minimum value, and a pixel value of pixels existing in a predetermined range in such a difference image, Alternatively, an intermediate value or a difference between these maximum value and minimum value may be determined as the reference value.

Returning to FIG. 5, the image defect inspection apparatus 10 further includes a predetermined macro area including a plurality of image blocks (part images 81 in the above example) as a unit for calculating a reference value, in the macro area. A distribution information determination unit 22 that calculates distribution information of reference values determined for each image block is provided.
Here, the macro region may be a region including a plurality of partial images 81 as indicated by, for example, a two-dot chain line in FIG. The distribution information determination unit 22 determines distribution information related to a certain macro region as a set of reference values determined for each of a plurality of image blocks (that is, partial images 81) included in the macro region. Moreover, you may determine as a dispersion | distribution value of the reference values which are originally planned to become the same value among these reference values.

Furthermore, the image defect inspection apparatus 10 resets the defect detection conditions in each macro area according to the distribution information determined in each macro area, and resets the defects detected by the defect detection unit 8 in the macro area. A defect output availability determination unit 23 that determines whether or not to output under the detected defect detection condition.
For example, the defect output availability determination unit 23 inputs defect information relating to each defect detected by the defect detection unit 8 and determines a detection threshold included in the defect information of each defect for the macro region to which the defect belongs. The gray level difference of the defect included in the defect information of the defect is compared with the reset detection threshold, and the gray level difference becomes the detection threshold. When exceeding, the output is permitted with the defect information regarded as a true defect. Conversely, if the gray level difference does not exceed the detection threshold, the defect information is regarded as a pseudo defect and output is prohibited.

In addition, the defect output possibility determination unit 23 uses, for example, the defect detection parameters (for example, the slope a and the intercept b of the approximate straight line) included in the defect information of each defect for distribution information determined for the macro region to which the defect belongs. And the detection threshold is reset by the corrected approximate curve, and the defect gray level difference included in the defect information of the defect is compared with the reset detection threshold, so that the defect information It may be determined whether or not output is possible.
In this way, each defect detected by the defect detection unit 8 is detected again under the defect detection conditions reset by the defect output availability determination unit 23, thereby depending on the distribution information determined for each macro region. The defect detection condition is changed.

When the distribution information regarding a certain macro area is determined as a set of reference values determined for each image block included in the macro area by the distribution information determination section 22, the defect output availability determination section 23 includes the distribution information. Of the included reference values, the defect detection conditions are reset so that the defect detection sensitivity decreases as the variation between the reference values that are originally supposed to be the same increases. For example, the detection threshold is reset so as to increase in accordance with an increase in variation between reference values that are originally supposed to be the same value.
The defect output possibility determination unit 23, for example, the reference values determined for the respective partial images 81 obtained by imaging the same portion of the chip with respect to the plurality of chips (die) 3a are supposed to be the same value as the above. It may be a value. Then, the defect detection conditions may be reset so that the defect detection sensitivity decreases as the variation between these reference values increases.
Distribution information related to a certain macro area is determined as a dispersion value between reference values that are originally supposed to be the same among the reference values determined for each image block included in the macro area by the distribution information determination unit 22. In this case, the defect output availability determination unit 23 resets the defect detection condition so that the defect detection sensitivity decreases as the distribution information increases.

In the above or the following description, a unit of an image block obtained by dividing an inspection image, which is a unit for calculating a reference value, is referred to as a partial image (logical frame), which is a unit in which the difference detection unit 6 performs one image comparison. However, other than this, the size (unit) of the image block may be freely determined.
For example, in the image block, an image obtained by imaging one chip (die) 3a formed on the semiconductor wafer surface is used as one unit (that is, an image obtained by imaging one chip 3a is used as one image block). B) The unit of the image block may be determined. When color unevenness that causes a gradual change in brightness difference occurs, it is necessary to acquire distribution information over a wide range in the inspection image. By setting a relatively large image block in this way, The calculation amount of the reference value can be saved.
If each image block is determined for each image obtained by imaging one chip in this way, the image obtained by imaging each chip is originally supposed to be the same, so that each image block is originally the same image. It is possible to determine the reference value to be the same value because the reference value determination method can be determined so that the block or the reference value determined for each image block is essentially the same.

When the pattern formed on the surface of the semiconductor wafer to be inspected is formed by an exposure process (lithography process) using an optical or electron beam, the pattern is exposed on the surface of the semiconductor wafer when the pattern is exposed on the surface of the semiconductor wafer. In some cases, the pattern is exposed in a state where no image is formed (defocused state), resulting in a defective product. In the case of a semiconductor wafer exposed and patterned in such a defocused state, color unevenness is also observed in the captured image on the surface. This color unevenness occurs in such a manner that the brightness difference changes for each range exposed by a single reticle shot (that is, for each range exposed simultaneously by one exposure mask). When the chip (die) is exposed, it is necessary to acquire distribution information in a wider range.
Therefore, the reference value determination unit 21 converts the image in the range exposed by one reticle shot of the inspection image obtained by imaging the surface of the semiconductor wafer on which the pattern is formed in the lithography process to be inspected into image block units. It may be determined as follows.
Thus, if each image block is determined for each image in the range exposed by one reticle shot, the image in the range exposed by one reticle shot is originally supposed to be the same. It is possible to determine image blocks so that they are essentially the same image, or to determine a reference value determination method so that the reference values determined for each image block are essentially the same. Is possible.

FIG. 8 is a block diagram of a second embodiment of the image defect inspection apparatus for a semiconductor circuit according to the present invention. In the image defect inspection apparatus 10 according to the present embodiment, the reference value determination unit 21 determines, for each image block, a detection threshold that is a defect detection condition used for defect detection in each image block as a reference value. .
As described above, the detection threshold calculation unit 7 determines the detection threshold according to the distribution of the gray level difference between the pixel value of each pixel included in each inspection partial image 81 and the pixel value of each pixel of the reference image. Even by referring to the distribution state of the threshold, color unevenness occurring in the inspection image can be detected.
Therefore, in the example illustrated in FIG. 8, the reference value determination unit 21 inputs defect information detected in each inspection partial image 81 that is an image block from the defect detection unit 8, and the defect included in each defect information The detection threshold used at the time of detection is determined as a reference value.

Alternatively, the reference value determination unit 21 uses, for each image block, a defect detection parameter (see FIG. 4) used when determining a detection threshold that is a defect detection condition used in defect detection in each image block. In the example of the detection threshold value determination method described above, the slope a and the intercept b) of the approximate line may be determined as the reference value.
In this case, in the example illustrated in FIG. 8, the reference value determination unit 21 inputs defect detection parameters detected in each inspection partial image 81 that is an image block from the defect detection unit 8 and is included in each defect information. A defect detection parameter used when detecting the defect is determined as a reference value.

FIG. 9 is a block diagram of a third embodiment of the image defect inspection apparatus for a semiconductor circuit according to the present invention. In the embodiment shown in FIGS. 5 and 8, the detection threshold calculation unit 7 automatically calculates the detection threshold, and the defect detection unit 8 performs defect detection under the determined detection threshold, and then the defect is detected. The output threshold determination unit 23 resets the detection threshold value, and determines again whether or not the defect is output as an inspection result.
In the image defect inspection apparatus 10 according to the present embodiment, prior to the defect detection by the defect detection unit 8, the distribution information determination unit 22 determines the distribution information described above, and the detection threshold calculation unit 7 based on the distribution information. The defect detection unit 8 performs defect detection after determining a detection threshold value that is a defect detection condition.

Here, the detection threshold value calculation unit 7 may determine the detection threshold value and the defect detection parameter based only on the distribution information, or the initial value of the detection threshold value according to the detection threshold value calculation method described above with reference to FIG. May be determined and corrected according to the distribution information.
At this time, when the distribution information regarding a certain macro region is determined as a set of reference values determined for each image block included in the macro region by the distribution information determining unit 22, the detection threshold value calculating unit 7 Of each reference value included in the information, the defect detection condition is set so that the defect detection sensitivity decreases as the variation between the reference values that are originally supposed to be the same increases. For example, the detection threshold is reset so that the variation increases as the variation increases. Further, the distribution information related to a certain macro area is a dispersion value between reference values that are originally supposed to be the same among the reference values determined for each image block included in the macro area by the distribution information determination unit 22. If determined, the detection threshold value calculation unit 7 sets the defect detection condition so that the defect detection sensitivity decreases as the distribution information increases.
Here, when an image block which is one unit for determining a reference value is determined as an image block having a smaller number of pixels than the number of pixels captured by one chip, such as an inspection partial image (logical frame), a plurality of image blocks are determined. The reference value determined for each image block obtained by imaging the same portion in the chip (die) 3a may be the reference value that is supposed to be the same value as described above.
Further, when an image block is defined for each image obtained by imaging one chip or for each image obtained by imaging one image in a range exposed by one reticle shot, each image block is essentially the same. Since the block can be determined so as to be an image, or the determination method can be determined so that the reference value determined for each block is essentially the same value, the reference value determined for each image block is the same. Can be scheduled when it comes to value.

Since the distribution information to be acquired by the distribution information determination unit 22 indicates the distribution of the brightness difference in a relatively wide range of the inspection target, the image resolution required for the reference value determination unit 21 to determine the reference value Is lower than the image resolution required for the defect detection unit 8 to detect a defect. Therefore, the captured image used when the reference value determining unit 21 determines the reference value may be an image different from the inspection image used when the defect detecting unit 8 performs defect detection.
That is, the reference value determination unit 21 may determine the reference value according to the pixel value of the pixel of the captured image of the semiconductor wafer 3 that is different from the inspection image used when the defect detection unit 8 performs defect detection.

For example, in the example shown in FIG. 9, the inspection image used when the defect detection unit 8 performs defect detection is stored in the first image storage unit 5, and the reference value determination unit 21 determines the reference value. The captured image to be used is stored in the second image storage unit 25. The second image storage unit 25 stores a captured image obtained by thinning out pixels at a predetermined pitch among image signals output from the imaging device 4. Alternatively, without providing the second image storage unit 25 separately from the first image storage unit 5, the reference value determination unit 21 converts the image signal stored in the first image storage unit 5 into pixels at a predetermined pitch. You may input by thinning out.
In addition, for example, the second image storage unit 25 uses the imaging device 4 to capture images at a higher speed and lower magnification than when the defect detection unit 8 captures an inspection image used when performing defect detection. A captured image may be stored.

FIG. 10 is a block diagram of a fourth embodiment of the image defect inspection apparatus for a semiconductor circuit according to the present invention. In the image defect inspection device 10 according to the present embodiment, the reference value determination unit 21 determines the reference value separately from the first imaging device 4 that captures an inspection image used when the defect detection unit 8 performs defect detection. A second image storage unit 24 for capturing a captured image to be used when performing the processing.
That is, the reference value determination unit 21 is included in the captured image captured by the second imaging device 24 provided to image the semiconductor wafer 3 separately from the first imaging device 4 that obtains the inspection image. The reference value is determined according to the pixel value of the pixel to be recorded.

  By providing the second imaging device 24 separately from the first imaging device 4 that captures the inspection image, the reference value determination unit 21 and the distribution information determination unit 22 are in parallel with the defect detection by the defect detection unit 8. It becomes easy to configure the image defect inspection apparatus 10 so as to determine the reference value and the distribution information, respectively. For the above-described reason, the second imaging device 24 may be an imaging device that captures images with a lower resolution or lower magnification than the first imaging device 4.

FIG. 11 is a block diagram of a first embodiment of an image defect inspection system for a semiconductor circuit according to the present invention. The captured images used by the reference value determination unit 21 and the distribution information determination unit 22 to determine the reference value and the distribution information, respectively, need to be limited to those captured by the imaging device provided in the image defect inspection apparatus 10. There is no.
In other words, the reference value determination unit 21 and the distribution information determination unit 22 perform imaging provided separately from the imaging device provided in the image defect inspection apparatus 10 before the image defect inspection apparatus 10 performs the appearance inspection of the semiconductor wafer 3. The reference value and the distribution information may be determined using a captured image obtained by capturing the semiconductor wafer 3 with an apparatus.

Therefore, in the image defect inspection system shown in FIG. 11, when the detection threshold value calculation unit 7 of the image defect inspection apparatus 10 determines the defect detection condition separately from the image defect inspection apparatus 10 and the image defect inspection apparatus 10. And an imaging device 50 that acquires a captured image of the semiconductor wafer 3 that is used to determine the reference value and the distribution information.
The imaging device 50 includes an imaging device 51 that images the semiconductor wafer 3 to be inspected, and a data output unit 52 that outputs data such as a captured image captured by the imaging device 51 to the image defect inspection device 10. .

  On the other hand, the image defect inspection apparatus 10 is provided with a data input unit 26 for inputting captured image data output from the imaging apparatus 50. Data exchange between the data output unit 52 on the imaging device 50 side and the data input unit 26 on the image defect inspection device 10 side may be performed on-line via a wired or wireless signal transmission path, or It may be performed in an offline manner via an information storage medium such as a flexible disk, a CD-ROM, or a removable medium.

The reference value determination unit 21 provided in the image defect inspection apparatus 10 is included in a captured image obtained by imaging the respective areas by the imaging apparatus 50 for each area having a predetermined size on the semiconductor wafer 3 to be inspected. In accordance with the pixel value to be determined, the reference value is determined in the same manner as described above.
The distribution information determination unit 22 determines a macro area determined on the semiconductor wafer 3 so as to include a plurality of areas having the predetermined size for each area having the predetermined size included in the macro area. The distribution information of the reference value is determined.
And the detection threshold value calculation part 7 changes the detection threshold value which is defect detection conditions according to the distribution information determined in the macro area | region. At this time, the detection threshold value calculation unit 7 detects the detection threshold value so that the defect detection sensitivity decreases as the variation between the reference values that are supposed to be the same among the reference values included in the distribution information increases. change. For example, the detection threshold value is changed so as to increase as the variation increases.
Here, when the area of the predetermined size, which is a unit for determining the reference value, is determined as an area smaller than one chip, the same part in the chip is imaged with respect to a plurality of chips (die) 3a. The reference value determined for each of the images may be the reference value that is expected to be the same value as the above. Further, when the predetermined size region is determined for each range of one chip or for each range exposed by one reticle shot, the images obtained by capturing the predetermined size region are essentially the same. The predetermined size area can be determined so as to be an image, or the determination method can be determined so that the reference value determined for each area is originally the same value. It is possible to schedule.

FIG. 12 is a block diagram of a second embodiment of the image defect inspection system for a semiconductor circuit according to the present invention. In the present embodiment, for each region of a predetermined size on the semiconductor wafer 3 to be inspected, the imaging device 51 determines a reference value according to the pixel value included in the captured image obtained by capturing each region. A reference value determination unit 53 is provided on the imaging device 50 side.
The data output unit 52 outputs reference value data to the image defect inspection apparatus 10 instead of the captured image data, and the data input unit 26 on the image defect inspection apparatus 10 side inputs the reference value data.
The distribution information determination unit 22 on the image defect inspection apparatus 10 side has the predetermined size included in the macro region for the macro region defined on the semiconductor wafer 3 so as to include a plurality of the regions having the predetermined size. The reference value distribution information determined by the reference value determination unit 53 on the imaging device 50 side is determined for each region. And the detection threshold value calculation part 7 changes the detection threshold value which is a defect detection condition according to the determined distribution information similarly to the method demonstrated with reference to FIG.

FIG. 13 is a block diagram of a third embodiment of the image defect inspection system for a semiconductor circuit according to the present invention. In the present embodiment, the distribution information of the reference value determined for each of the predetermined size areas included in the macro area is further obtained for the macro area configured to include a plurality of the predetermined size areas. A distribution information determination unit 54 for determination is provided on the imaging device 50 side.
The data output unit 52 outputs the distribution information to the image defect inspection apparatus 10 and the data input unit 26 on the image defect inspection apparatus 10 side inputs the distribution information.
Similar to the method described above with reference to FIG. 11, the detection threshold calculation unit 7 on the image defect inspection apparatus 10 side changes the detection threshold that is the defect detection condition according to the distribution information input from the imaging device 50.

FIG. 14 is a block diagram of a fourth embodiment of the image defect inspection system for a semiconductor circuit according to the present invention.
The color unevenness generated in the inspection image obtained by imaging the semiconductor wafer 3 is caused by a change in the film thickness of a transparent or semi-transparent film such as an insulating layer formed on the surface of the semiconductor wafer 3, so that the film formed on the surface of the semiconductor wafer 3 The color unevenness can also be detected by measuring the film thickness of each layer at each location on the wafer 3 and creating the distribution information using the measured value as a reference value.
That is, the reference value determination unit 21 and the distribution information determination unit 22 are measured by a film thickness measurement device prepared separately from the image defect inspection apparatus 10 before the appearance inspection of the semiconductor wafer 3 is performed by the image defect inspection apparatus 10. Alternatively, the reference value and the distribution information may be determined using film thickness data at each location of the semiconductor wafer 3.

For this reason, in the image defect inspection system shown in FIG. 14, the reference value and the distribution information used when the image defect inspection apparatus 10 and the detection threshold value calculation unit 7 of the image defect inspection apparatus 10 determine the defect detection condition. And a film thickness measuring device 60 for measuring a film thickness value of the film thickness formed on the surface of the semiconductor wafer 3.
The film thickness measuring device 60 measures the film thickness of a transparent or translucent film such as an insulating layer formed on the surface of the semiconductor wafer 3 to be inspected, and the film thickness measurement data. A data output unit 62 for outputting to the image defect inspection apparatus 10 is provided.

  On the other hand, the image defect inspection apparatus 10 is provided with a data input unit 26 for inputting film thickness measurement data output from the film thickness measurement apparatus 60. Data exchange between the data output unit 62 on the film thickness measuring device 60 side and the data input unit 26 on the image defect inspection device 10 side may be performed by the above-described online method or offline method.

Then, the reference value determination unit 21 provided in the image defect inspection apparatus 10 has a film thickness measured by the film thickness measuring device 60 in each of the areas of a predetermined size on the semiconductor wafer 3 to be inspected. According to the measured value, the reference value is determined as described above.
The distribution information determination unit 22 determines a macro area determined on the semiconductor wafer 3 so as to include a plurality of areas having the predetermined size for each area having the predetermined size included in the macro area. The distribution information of the reference value is determined.
And the detection threshold value calculation part 7 changes the detection threshold value which is defect detection conditions according to the distribution information determined in the macro area | region. At this time, the detection threshold value calculation unit 7 detects the detection threshold value so that the defect detection sensitivity decreases as the variation between the reference values that are supposed to be the same among the reference values included in the distribution information increases. change. For example, the detection threshold value is changed so as to increase as the variation increases.
Here, when the area of the predetermined size, which is one unit for determining the reference value, is determined as an area smaller than one chip, measurement is performed at the same location in the chip with respect to a plurality of chips (die) 3a. The reference value determined for each measured value may be the reference value that is expected to be the same value as the above. Further, when the predetermined size region is determined for each range of one chip or for each range exposed by one reticle shot, the measured value measured in the predetermined size region is The measurement location in each area is determined so that the same measurement value is originally obtained (for example, measurement is performed at the same position in each chip or each reticle shot), and the reference value determined for each area is originally the same value. Thus, the reference value can be scheduled to be the same value.

FIG. 15 is a block diagram of a fifth embodiment of the image defect inspection system for a semiconductor circuit according to the present invention. In the present embodiment, for each region of a predetermined size on the semiconductor wafer 3 to be inspected, the reference value is determined by the film thickness measurement unit 61 according to the film thickness measurement value measured in each of these regions. The value determining unit 63 is provided on the film thickness measuring device 60 side.
The data output unit 62 outputs reference value data to the image defect inspection apparatus 10 instead of the film thickness measurement value data, and the data input unit 26 on the image defect inspection apparatus 10 side inputs this.
The distribution information determination unit 22 on the image defect inspection apparatus 10 side has the predetermined size included in the macro region for the macro region defined on the semiconductor wafer 3 so as to include a plurality of the regions having the predetermined size. The reference value distribution information determined by the reference value determination unit 63 on the imaging device 60 side is determined for each region.
The detection threshold value calculation unit 7 on the image defect inspection apparatus 10 side changes the detection threshold value that is a defect detection condition as described above with reference to FIG. 14 according to the determined distribution information.

FIG. 16 is a block diagram of a sixth embodiment of the image defect inspection system for a semiconductor circuit according to the present invention. In the present embodiment, the distribution information of the reference value determined for each of the predetermined size areas included in the macro area is further obtained for the macro area configured to include a plurality of the predetermined size areas. A distribution information determining unit 64 for determining is provided on the film thickness measuring device 60 side.
The data output unit 62 outputs this distribution information to the image defect inspection apparatus 10, and the data input unit 26 on the image defect inspection apparatus 10 side inputs the distribution information.
The detection threshold value calculation unit 7 on the image defect inspection apparatus 10 side changes the detection threshold value that is the defect detection condition as described above with reference to FIG. 14 according to the distribution information input from the film thickness measurement apparatus 60.

FIG. 17 is a block diagram of a seventh embodiment of the image defect inspection system for a semiconductor circuit according to the present invention. When a brightness difference (color unevenness) occurs in a captured image obtained by imaging the surface of the semiconductor wafer 3, the critical dimensions of the minimum dimension of the pattern formed on the semiconductor wafer 3 also vary, so that the semiconductor It is also possible to detect color unevenness by measuring the dimensions of critical dimensions formed at various locations on the surface of the wafer 3 with a scanning electron microscope and creating distribution information using the measured values as reference values. is there.
That is, the reference value determination unit 21 and the distribution information determination unit 22 are measured by a scanning electron microscope apparatus prepared separately from the image defect inspection apparatus 10 before the appearance inspection of the semiconductor wafer 3 is performed by the image defect inspection apparatus 10. The reference value and the distribution information may be determined using the critical dimension measurement values at each location of the semiconductor wafer 3.

  For this reason, in the image defect inspection system shown in FIG. 17, the reference value and the distribution information used when the image defect inspection apparatus 10 and the detection threshold calculation unit 7 of the image defect inspection apparatus 10 determine the defect detection condition. And a scanning electron microscope apparatus 70 that measures the critical dimension dimension of the pattern formed on the surface of the semiconductor wafer 3.

  The scanning electron microscope apparatus 70 includes an electron gun 71 that generates an electron beam EB to be irradiated on the semiconductor wafer 3 to be inspected, a deflector 72 for scanning the semiconductor wafer 3 with the electron beam EB, and the semiconductor wafer 3. An electron detector 73 for detecting the electron beam EB reflected above, a signal processing circuit 74 for converting a current intensity signal of the electron detector 73 for detecting the electron beam EB into a digital intensity signal, and the intensity signal and the electron Based on the scanning position of the beam EB, an image generation unit 75 that generates a high-magnification image of the surface of the semiconductor wafer 3, a CD measurement unit 76 that measures the critical dimension of a pattern that appears in the image generated by the image generation unit 75, and A data output unit 77 for outputting the critical dimension measurement value data to the image defect inspection apparatus 10 is provided.

  On the other hand, the image defect inspection apparatus 10 is provided with a data input unit 26 for inputting critical dimension measurement value data output from the film thickness measurement apparatus 60. Data exchange between the data output unit 77 on the scanning electron microscope apparatus 70 side and the data input unit 26 on the image defect inspection apparatus 10 side may be performed by the above-described online method or offline method.

Then, the reference value determination unit 21 provided in the image defect inspection apparatus 10 has a critical value measured by the scanning electron microscope apparatus 70 in each of the areas of a predetermined size on the semiconductor wafer 3 to be inspected. In accordance with the dimension measurement value, the reference value is determined as described above.
The distribution information determination unit 22 determines a macro area determined on the semiconductor wafer 3 so as to include a plurality of areas having the predetermined size for each area having the predetermined size included in the macro area. The distribution information of the reference value is determined.
And the detection threshold value calculation part 7 changes the detection threshold value which is defect detection conditions according to the distribution information determined in the macro area | region. At this time, the detection threshold value calculation unit 7 detects the detection threshold value so that the defect detection sensitivity decreases as the variation between the reference values that are supposed to be the same among the reference values included in the distribution information increases. change. For example, the detection threshold value is changed so as to increase as the variation increases.
Here, when the area of the predetermined size, which is one unit for determining the reference value, is determined as an area smaller than one chip, measurement is performed at the same location in the chip with respect to a plurality of chips (die) 3a. The reference value determined for each measured value may be the reference value that is expected to be the same value as the above. Further, when the predetermined size region is determined for each range of one chip or for each range exposed by one reticle shot, the measured value measured in the predetermined size region is The measurement location in each area is determined so that the same measurement value is originally obtained (for example, measurement is performed at the same position in each chip or each reticle shot), and the reference value determined for each area is originally the same value. Thus, the reference value can be scheduled to be the same value.

FIG. 18 is a block diagram of an eighth embodiment of an image defect inspection system for a semiconductor circuit according to the present invention. In this embodiment, for each region of a predetermined size on the semiconductor wafer 3 to be inspected, a reference value is determined in accordance with the critical dimension measurement value measured by the scanning electron microscope apparatus 70 in each region. A reference value determination unit 78 is provided in the scanning electron microscope apparatus 70.
The data output unit 77 outputs reference value data to the image defect inspection apparatus 10 instead of the critical dimension measurement value, and the data input unit 26 on the image defect inspection apparatus 10 side inputs this.
The distribution information determination unit 22 on the image defect inspection apparatus 10 side has the predetermined size included in the macro region for the macro region defined on the semiconductor wafer 3 so as to include a plurality of the regions having the predetermined size. The reference value distribution information determined by the reference value determination unit 78 on the scanning electron microscope apparatus 70 side is determined for each region.

FIG. 19 is a block diagram of a ninth embodiment of an image defect inspection system for a semiconductor circuit according to the present invention. In the present embodiment, the distribution information of the reference value determined for each of the predetermined size areas included in the macro area is further obtained for the macro area configured to include a plurality of the predetermined size areas. A distribution information determination unit 79 for determination is provided on the scanning electron microscope apparatus 70 side.
The data output unit 77 outputs the distribution information to the image defect inspection apparatus 10 and the data input unit 26 on the image defect inspection apparatus 10 side inputs the distribution information.
The detection threshold calculation unit 7 on the image defect inspection apparatus 10 side changes a detection threshold that is a defect detection condition in accordance with the distribution information input from the film thickness measurement apparatus 60.

FIG. 20 is a block diagram of a fifth embodiment of the image defect inspection apparatus for a semiconductor circuit according to the present invention.
In the image defect inspection apparatus 10 according to this embodiment, first, the defect information creation unit 9 creates defect information in a predetermined format for each of the defects detected by the defect detection unit 8.
Here, the format of this defect information includes the detection position (defect position), the gray level difference between the inspection partial image at the defect position and the reference image, the partial image including the pixel at the defect position in the inspection partial image, It is determined so as to include information relating to the detected defect, such as a detection threshold and a defect detection parameter used when detecting the defect. Such a partial image, a detection threshold value, and a defect detection parameter are determined according to a pixel or an image pixel value determined corresponding to each location on the inspection image 80 (a location where a defect is detected in this example). In addition, since it is information that varies according to the pixel determined corresponding to each location on the inspection image 80 and the pixel value of the image, it will be referred to as “pixel value related information” in the present specification.
Then, a predetermined reference value is determined for each piece of defect information based on the pixel value related information, and further, distribution information of reference values in each macro region is determined, and defect detection in each macro region is performed according to the distribution information. Each condition is reset, and whether or not each defect information detected in each macro area is output is determined.

Since the reference values reflect pixel values at a plurality of locations on the inspection image, if the defect information is created over almost the entire area of the inspection image, the distribution information of the reference values in a macro area having a certain extent Thus, it is possible to detect the presence or absence of color unevenness by observing the variation of the pixel value (gray level value) within a certain range of width.
Then, the defect detection conditions are reset so as to change according to the distribution information (in the macro area where the dispersion of the distribution is large and the color unevenness is large, the defect detection conditions having a relatively low defect detection sensitivity are set, In a small macro area, defect detection conditions with relatively high defect detection sensitivity are set.) By determining whether or not defect information can be output under the reset defect detection conditions, pseudo defect output caused by color unevenness is output. Can be prevented.

  Hereinafter, the operation of each part of the image defect inspection apparatus 10 according to the present embodiment will be described in detail. Since the image defect inspection apparatus 10 according to the present embodiment has a configuration similar to the image defect inspection apparatus described above with reference to FIG. 5, the same reference numerals are given to the same components. A description of the same operation relating to components having the same reference numerals will be omitted.

  The defect detection unit 8 detects a defect by comparing the gray level difference output from the difference detection unit 6 with the detection threshold value output from the detection threshold value calculation unit 7, and detects a detection position (defect position) or a defect position. The information regarding the detected defect, such as the gray level difference between the inspection partial image and the reference image in, is output to the defect information creation unit 9. The defect information creating unit 9 includes a defect including this information in order to output the information regarding the input defect to other devices such as an automatic defect classification device, a display device, and a server that use information regarding the detected defect. Information is created for each defect according to a predetermined format.

The format of the defect information can be defined so that various information to be used for defect classification by the automatic defect classification apparatus is included in the defect information. For example, the above-described pixel value related information such as a partial image including the pixel at the position of the defect in the inspection partial image 81 and the detection threshold value and defect detection parameter used when detecting the defect are included in the defect information.
The pixel value related information that can be included in the defect information is, for example, the inspection partial image 81 in which the defect indicated in the defect information is detected, or the pixel at the position of this defect in the reference image 82 corresponding to the inspection partial image 81. A partial image including In addition, the inspection partial image 81 in which the defect indicated in the defect information is detected and the reference image 82 corresponding to the inspection partial image 81 may be used as the pixel value related information.

  Further, the difference image between the inspection partial image 81 in which the defect indicated in the defect information is detected and the reference image 82 corresponding to the inspection partial image 81 may be used as the pixel value related information, and the inspection in which the defect is detected A difference image between the partial image including the pixel at the defect position in the partial image 81 and the partial image including the pixel at the defect position in the reference image 82 corresponding to the inspection partial image 81 is represented by the pixel value related information. It is good. Furthermore, a detection threshold and a defect detection parameter used when a defect indicated in the defect information is detected may be included. The defect information creation unit 9 outputs defect information including such pixel value related information to the reference value determination unit 21.

The reference value determination unit 21 determines a predetermined reference value for each defect information, that is, for each pixel value related information, according to the pixel value related information included in the defect information.
For example, as the pixel value related information, the reference value determining unit 21 selects the pixel at the position of the defect in the inspection partial image 81 in which the defect indicated in the defect information is detected or the reference image 82 corresponding to the inspection partial image 81. If a partial image is included, the average value, variance value, maximum value, minimum value, or intermediate value between the maximum value and minimum value of the pixel values included in one or both of these partial images Or the difference may be determined as a reference value. Alternatively, the reference value determination unit 21 may include a partial image including a pixel at a defect position in the inspection partial image 81 and a partial image including a pixel at a defect position in the reference image 82 corresponding to the inspection partial image 81. An average value, a variance value, a maximum value, a minimum value, or an intermediate value or a difference between the maximum value and the minimum value may be determined as a reference value.

As the pixel value related information, between the partial image including the pixel at the defect position in the inspection partial image 81 and the partial image including the pixel at the defect position in the reference image 82 corresponding to the inspection partial image 81. When a difference image is given, the reference value determination unit 21 calculates an average value, variance value, maximum value, minimum value of pixel values included in the difference image, an intermediate value between these maximum value and minimum value, The difference may be determined as a reference value.
When the inspection partial image 81 in which the defect indicated in the defect information is detected or the reference image 82 corresponding to the inspection partial image 81 is given as the pixel value related information, either one or both of these images are given. The pixel value at a predetermined position in the image, the average value, the variance value, the maximum value, the minimum value, or the maximum value and the minimum value of the pixel values included in one or both of these images An intermediate value or a difference may be determined as a reference value. Alternatively, the pixel value at a predetermined position in the difference image between the inspection partial image 81 and the reference image 82 corresponding to the inspection partial image 81, the average value, the variance value, and the maximum value of the pixel values included in the difference image The minimum value or an intermediate value or difference between the maximum value and the minimum value may be determined as the reference value.

When the difference image between the inspection partial image 81 in which the defect indicated in the defect information is detected and the reference image 82 corresponding thereto is given as the pixel value related information, a predetermined position in the difference image is obtained. A pixel value, an average value, a variance value, a maximum value, a minimum value, or an intermediate value or a difference between these maximum and minimum values may be determined as a reference value.
When the detection threshold and the defect detection parameter used when the defect indicated in the defect information is detected as the pixel value related information, the detection threshold and the defect detection parameter are determined as reference values. Good.

  When determining the reference value, the reference value determining unit 21 may determine one reference value for each inspection partial image 81 or for each partial image obtained by dividing the inspection image by a predetermined number of pixels. Such a partial image serving as a unit for determining a reference value may be referred to as a “reference value determination unit image” in this specification. For example, when a plurality of defects are detected in a certain reference value determination unit image, the reference value determination unit 21 uses the reference value determined for any one of these defects as a representative value, as a reference value determination unit. A reference value for each image may be determined. Alternatively, a predetermined calculation value between reference values determined for each of the defects in the reference value determination unit image may be obtained and used as a reference value for each reference value determination unit image.

Returning to FIG. 20, the distribution information determination unit 22 detects an image region (macro region) having a predetermined size defined in the inspection image obtained by imaging the semiconductor wafer 3 in the inspection partial image 81 included in the macro region. The distribution information of the reference value determined for each defect is determined. The description of the macro area is as described above.
The distribution information determining unit 22 determines, as reference value distribution information regarding the macro area, for each of the plurality of inspection partial images 81 included in a certain macro area, regarding any of the defects detected in the inspection partial image 81. A variance value of the reference value may be determined. Alternatively, a set of reference values determined for defects detected in each of the inspection partial images 81 included in the macro area may be determined as distribution information.

Further, when the reference value is determined for each reference value determination unit image as described above, the macro area is defined as an area larger than one reference value determination unit image, and each reference value determination unit image in this macro area is determined. The distribution information of the reference value determined in (1) is determined.
Further, the defect output possibility determination unit 23 resets a detection threshold as a defect detection condition in accordance with the distribution information determined for the macro area, and the defect information detected in the inspection partial image 81 included in the macro area. Whether output is possible is determined under the reset defect detection conditions.
For example, the defect output possibility determination unit 23 inputs defect information related to each defect detected by the defect detection unit 8 and determines a detection threshold included in the defect information of each defect for the macro region to which the defect belongs. If the gray level difference exceeds the detection threshold by re-setting by correcting according to the distributed information, and comparing the gray level difference of this defect contained in the defect information with the reset detection threshold To allow the output of the defect information as a true defect. Conversely, if the gray level difference does not exceed the detection threshold, the defect information is regarded as a pseudo defect and output is prohibited.

In addition, the defect output possibility determination unit 23 uses, for example, the defect detection parameters (for example, the slope a and the intercept b of the approximate straight line) included in the defect information of each defect for distribution information determined for the macro region to which the defect belongs. And the detection threshold is reset by the corrected approximate curve, and the defect gray level difference included in the defect information of the defect is compared with the reset detection threshold, so that the defect information It may be determined whether or not output is possible.
In this manner, each defect detected in the defect detection unit 8 is detected again under the defect detection conditions reset by the defect output availability determination unit 23, so that the defect is determined according to the distribution information determined for the macro area. The detection condition is changed.

When the distribution information regarding a certain macro area is determined as a set of reference values determined for each inspection partial image 81 included in the macro area, the defect output availability determination unit 23 determines each reference included in the distribution information. The defect detection conditions are reset so that the defect detection sensitivity decreases as the variation between the reference values that are originally supposed to be the same among the values increases. For example, the detection threshold is reset so as to increase in accordance with an increase in variation between reference values that are originally supposed to be the same value.
For example, the defect output availability determination unit 23 determines the reference value determined for each partial image 81 (which may be the above-described reference value determination unit image) obtained by imaging the same portion of the chip with respect to the plurality of chips (die) 3a. It may be a reference value that is expected to be the same value as the above. Then, the defect detection conditions may be reset so that the defect detection sensitivity decreases as the variation between these reference values increases.
Further, when the distribution information regarding a certain macro area is determined as the dispersion value of the reference value determined for each inspection partial image 81 included in the macro area, the defect output possibility determination unit 23 originally has the same value. Then, the defect detection conditions are reset so that the defect detection sensitivity decreases as the distribution information determined as the dispersion value of the reference values increases.

As described above, according to the image defect inspection apparatus 10, for each macro area larger (wider) than the inspection partial image 81 (logical frame) that is a unit of an image for performing image comparison for defect detection, an inspection partial image is obtained. Since distribution information such as the average value of the pixel values included in 81 and the reference image can be obtained, it is possible to detect the presence or absence of color unevenness by observing the variation of the gray level value in a wide macro region.
Then, by resetting the defect detection condition according to such distribution information and determining whether or not the defect information can be output under the reset defect detection condition, the pseudo defect output caused by the color unevenness generated in the inspection image can be obtained. It becomes possible to prevent.

  As described above with reference to FIGS. 4A to 4C, the detection threshold value calculation unit 7 determines the detection threshold value and the defect detection parameter based on the pixel values of the inspection partial image 81 and the reference image. To calculate. Therefore, the distribution information of these detection thresholds and defect detection parameters can also be used for detecting color unevenness in the inspection image. At this time, the defect output possibility determination unit 23 assumes that the detection threshold value or the defect detection parameter calculated for each partial image 81 obtained by imaging the same portion in the chip with respect to the plurality of chips (die) 3a is the same value as the above. It may be a planned reference value.

  By the way, the defect information creation unit 9 determines the pixel value related information for each of a plurality of predetermined locations on the inspection image 80 regardless of the presence or absence of a defect in each location, and uses the pixel value related information. It is good also as producing dummy defect information including. Thereby, the reference value determination unit 21 can determine reference values for each of a plurality of predetermined locations on the inspection image 80 regardless of the presence or absence of defects. For example, if a fixed point that is uniformly distributed over the entire inspection image is determined as a location that determines pixel value related information, it is possible to obtain reference value distribution information at the fixed point that is uniformly distributed over the entire inspection image 80.

  At this time, the defect information creation unit 9 may include, as the pixel value related information, for example, an inspection partial image 81 at a predetermined location on the inspection image 80 or a reference image 82 corresponding thereto, in the defect information. A difference image between the inspection partial image 81 at a predetermined position on the inspection image 80 and the reference image 82 corresponding thereto may be included. Alternatively, the defect information creation unit 9 may include, as the pixel value related information, the detection threshold value or the defect detection parameter determined for the inspection partial image 81 at a predetermined location on the inspection image 80 in the defect information.

  Then, the reference value determining unit 21 receives, as pixel value related information, an inspection partial image 81 at a predetermined location on the inspection image 80 or a reference image 82 corresponding to the inspection partial image 81. The pixel value at a predetermined position in one or both images, the average value, the variance value, the maximum value, the minimum value, or the maximum value of the pixel values included in either or both of these images An intermediate value or a difference between the value and the minimum value may be determined as the reference value. Alternatively, the pixel value at a predetermined position in the difference image between the inspection partial image 81 and the reference image 82 corresponding to the inspection partial image 81, the average value, the variance value, and the maximum value of the pixel values included in the difference image The minimum value or an intermediate value or difference between the maximum value and the minimum value may be determined as the reference value.

When the difference image between the inspection partial image 81 at a predetermined location on the inspection image 80 and the corresponding reference image 82 is given as the pixel value related information, a predetermined value in the difference image is given. The pixel value of the position, the average value of the pixel values included in the difference image, the variance value, the maximum value, the minimum value, or an intermediate value or a difference between the maximum value and the minimum value may be determined as the reference value.
When detection threshold values and defect detection parameters determined for the inspection partial image 81 at a predetermined location on the inspection image 80 are given as pixel value related information, these detection threshold values and defect detection parameters are used as reference values. You may decide.

At this time, for example, dummy defect information, that is, a position where one pixel value related information or a reference value is created may be a position where a predetermined position in a plurality of chips (die) 3a formed on the semiconductor wafer 3 is imaged. If color unevenness that causes a gradual change in brightness difference occurs, it is necessary to acquire distribution information over a wide range in the inspection image. In this way, a reference value is determined for each relatively large range. By doing so, the amount of calculation of the reference value can be saved.
In this way, if the income position such as the pixel value for creating the reference value is determined as the same position of each chip, the image obtained by capturing each chip is originally supposed to be the same, so the pixel that is the basis for creating the reference value The value-related information can also be scheduled to have the same value, and the reference value can be scheduled to have the same value.

When the pattern formed on the surface of the semiconductor wafer 3 to be inspected is formed by an exposure process (lithography process) using an optical or electron beam, the defect information creation unit 9 uses dummy defect information, that is, one pixel. The position where the value related information and the reference value are created is a predetermined position within the range exposed by one reticle shot of the inspection image obtained by imaging the surface of the semiconductor wafer on which the pattern is formed in the lithography process to be inspected. It may be the imaged position.
When the income position such as the pixel value for creating the reference value is determined to be the same position in the range exposed by each reticle shot in this way, the images obtained by capturing the range exposed by each reticle shot are originally supposed to be the same. Therefore, the pixel value related information that is the basis for creating the reference value can be expected to have the same value, and the reference value can be expected to be the same value.

  The present invention relates to an image defect inspection apparatus, an image defect inspection system, and an image for comparing an inspection image obtained by imaging an inspection object with a reference image that should be essentially the same as the inspection image and detecting different portions as defects. It can be used for defect inspection methods. In particular, in order to detect defects in the semiconductor circuit pattern formed on the semiconductor wafer in the semiconductor manufacturing process, the surface of the semiconductor circuit wafer is imaged, and the captured image and the reference image are compared. The present invention can be used for an image defect inspection apparatus, an image defect inspection system, and an image defect inspection method to be detected.

It is a block diagram of the conventional external appearance inspection apparatus for semiconductor circuits. It is a figure which shows the arrangement | sequence of the die | dye on a semiconductor wafer. (A) is explanatory drawing of the picked-up image obtained when the imaging device of FIG. 1 is scanned relatively with respect to a wafer, (B) demonstrates the inspection partial image and reference image which are compared in an image defect inspection. It is a figure to do. It is a figure explaining the conventional image defect inspection method. 1 is a block diagram of a first embodiment of an image defect inspection apparatus for a semiconductor circuit according to the present invention. FIG. It is explanatory drawing of a logical frame. It is a figure explaining a macro area. It is a block diagram of 2nd Example of the image defect inspection apparatus for semiconductor circuits by this invention. It is a block diagram of 3rd Example of the image defect inspection apparatus for semiconductor circuits by this invention. It is a block diagram of 4th Example of the image defect inspection apparatus for semiconductor circuits by this invention. 1 is a block diagram of a first embodiment of an image defect inspection system for a semiconductor circuit according to the present invention. FIG. It is a block diagram of 2nd Example of the image defect inspection system for semiconductor circuits by this invention. It is a block diagram of 3rd Example of the image defect inspection system for semiconductor circuits by this invention. It is a block diagram of 4th Example of the image defect inspection system for semiconductor circuits by this invention. It is a block diagram of 5th Example of the image defect inspection system for semiconductor circuits by this invention. It is a block diagram of 6th Example of the image defect inspection system for semiconductor circuits by this invention. It is a block diagram of 7th Example of the image defect inspection system for semiconductor circuits by this invention. It is a block diagram of 8th Example of the image defect inspection system for semiconductor circuits by this invention. It is a block diagram of 9th Example of the image defect inspection system for semiconductor circuits by this invention. It is a block diagram of 5th Example of the image defect inspection apparatus for semiconductor circuits by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stage 2 Sample stand 3 Semiconductor wafer 4 Imaging device 5 Image memory | storage part 6 Difference detection part 7 Detection threshold value calculation part 8 Defect detection part 10 Image defect inspection apparatus 21 Reference value determination part 22 Distribution information determination part

Claims (72)

In the image defect inspection apparatus for comparing the inspection partial image obtained by dividing the inspection image obtained by imaging the inspection object with the reference image that should be essentially the same as the inspection partial image, and detecting different portions as defects,
A reference value determining unit that determines a reference value determined according to a predetermined determination method for each region of a predetermined size on the inspection target, according to a pixel value of a pixel included in an image obtained by imaging each of the regions;
A distribution information determination unit that determines distribution information of the reference value determined for each of the predetermined size areas included in the macro area for a macro area configured to include a plurality of the predetermined size areas; With
An image defect inspection apparatus that performs defect detection by changing defect detection conditions in accordance with the distribution information determined in the macro area.   The image defect inspection apparatus according to claim 1, wherein the reference value determination unit determines the reference value for each image block obtained by dividing the inspection image by a predetermined size.   The image defect according to claim 2, wherein the reference value determination unit determines the reference value according to a pixel value of a pixel existing at a predetermined position in the pixel block for each of the image blocks. Inspection device.   The reference value determining unit, for each image block, an average value, variance value, maximum value, minimum value of pixels included in the image block, or an intermediate value or difference between the maximum value and the minimum value, Or an average value, variance value, maximum value, minimum value of pixels included in the difference image between the image block and the reference image to be compared with the image block, or an intermediate value between the maximum value and the minimum value The image defect inspection apparatus according to claim 2, wherein a difference is determined as the reference value.   The defect detection condition is changed by changing a defect detection sensitivity according to a variation between the reference values that are supposed to be the same among the reference values included in the distribution information. Item 5. The image defect inspection apparatus according to any one of Items 2 to 4.   5. The defect detection condition is changed by changing defect detection sensitivity according to the distribution information determined as a dispersion value of the reference value by the distribution information determination unit. The image defect inspection apparatus according to item. A defect detection condition determining unit for determining the defect detection condition;
Detecting a difference between pixel values of corresponding pixels of the inspection partial image and the reference image, and detecting the pixel portion as a defect when the difference satisfies the defect detection condition; and
The defect detection condition in each macro area is reset according to the distribution information determined in each macro area, and the defect detected by the defect detection unit in the macro area is reset. A defect output availability determination unit that determines whether or not to output under
The image defect inspection apparatus according to any one of claims 2 to 4, further comprising:   The defect output availability determination unit is configured so that a defect detection sensitivity is lowered in accordance with an increase in variation between the reference values that are expected to be the same among the reference values included in the distribution information. The image defect inspection apparatus according to claim 7, wherein the defect detection condition is reset. The distribution information determination unit determines the distribution information as a variance value of the reference value,
The image defect inspection apparatus according to claim 7, wherein the defect output availability determination unit resets the defect detection condition so that the defect detection sensitivity decreases as the distribution information increases. . A defect detection condition determination unit for determining a detection threshold as the defect detection condition;
A defect detection unit that detects a difference between pixel values of corresponding pixels of the inspection partial image and the reference image, and detects the pixel part as a defect when the difference exceeds the detection threshold, and
The defect detection condition determination unit determines, for each inspection partial image, the detection threshold according to a predetermined determination method based on a difference distribution of pixel values between corresponding pixels of the inspection partial image and the reference image,
The image defect inspection apparatus according to claim 2, wherein the reference value determination unit determines the detection threshold as the reference value. A defect detection condition determination unit for determining a detection threshold as the defect detection condition;
A defect detection unit that detects a difference between pixel values of corresponding pixels of the inspection partial image and the reference image, and detects the pixel part as a defect when the difference exceeds the detection threshold, and
The defect detection condition determination unit calculates a defect detection parameter for each inspection partial image according to a predetermined calculation method based on a distribution of pixel value differences between corresponding pixels of the inspection partial image and the reference image. , Determining the detection threshold according to the defect detection parameter,
The image defect inspection apparatus according to claim 2, wherein the reference value determination unit determines the defect detection parameter as the reference value.   3. The image defect inspection apparatus according to claim 2, wherein the reference value determination unit uses the one inspection partial image, which is a unit of image comparison, as a unit of the image block. 4.   The reference value determination unit uses, as a unit of the image block, an image corresponding to one of a plurality of chips formed on the surface of the semiconductor wafer of the inspection image obtained by imaging the surface of the semiconductor wafer to be inspected. The image defect inspection apparatus according to claim 2.   The reference value determination unit is configured to display an image of a range exposed by one reticle shot of the inspection image obtained by imaging the surface of the semiconductor wafer on which a pattern is formed in the lithography process to be inspected, as a unit of the image block. The image defect inspection apparatus according to claim 2, wherein: A defect detection condition determination unit that determines a defect detection condition according to the distribution information determined in the macro region;
When a comparison result between the inspection partial image and the reference image satisfies the defect detection condition, a defect detection unit that detects different parts as defects, and
The image defect inspection apparatus according to claim 1, further comprising:   The said reference value determination part determines the said reference value according to the pixel value of the pixel which is the captured image of the said test object, and is contained in the captured image different from the said test | inspection image, It is characterized by the above-mentioned. Image defect inspection device.   The image defect inspection apparatus according to claim 16, wherein the captured image is an image obtained by thinning out pixels of the inspection image.   The image defect inspection apparatus according to claim 16, wherein the captured image is an image captured at a lower magnification than capturing the inspection image.   The distribution information determination unit determines the distribution information for the other macro region in parallel with the defect detection unit detecting a defect for one macro region on the inspection target. The image defect inspection apparatus according to claim 15. In addition to the first imaging unit that images the inspection object and obtains the inspection image, the image capturing apparatus further includes a second imaging unit that images the inspection object,
The image defect inspection apparatus according to claim 19, wherein the reference value determination unit determines the reference value according to a pixel value of a pixel included in a captured image captured by the second imaging unit. In the image defect inspection apparatus for comparing the inspection partial images obtained by dividing the inspection image into a plurality of inspection partial images and corresponding reference images that should be essentially the same, and detecting different portions as defects,
When a comparison result between the inspection partial image and the reference image satisfies a defect detection condition, a defect detection unit that detects different portions as defects,
For each of a plurality of locations on the inspection image, a reference value determination unit that determines a predetermined reference value according to a pixel value of a pixel determined corresponding to each location,
A distribution information determination unit that determines distribution information of the reference value determined in the image region for an image region of a predetermined size determined in the inspection image;
The defect detection condition is reset according to the distribution information determined for the image area, and the defect detection condition is reset to determine whether the defect detected in the inspection partial image included in the image area is output. A defect output availability determination unit determined under
An image defect inspection apparatus comprising:   The image defect inspection apparatus according to claim 21, wherein the reference value determination unit determines the reference value for each of the locations where the defect is detected by the defect detection unit.   The image defect inspection apparatus according to claim 22, wherein the image area is defined as an area larger than the inspection partial image. The inspection image is an image obtained by imaging a semiconductor wafer surface to be inspected,
23. The image defect inspection apparatus according to claim 22, wherein the image area of the predetermined size is an area obtained by imaging the entire surface or a part of the semiconductor wafer.   The reference value determination unit includes a pixel value at a predetermined position in the inspection partial image including the defect and / or the reference image corresponding thereto, or an average value, a variance value of pixel values included in these images, 23. The image defect inspection apparatus according to claim 22, wherein a maximum value, a minimum value, or an intermediate value or a difference between the maximum value and the minimum value is determined as the reference value.   The reference value determination unit includes a pixel value at a predetermined position in a difference image between the inspection partial image including the defect and the reference image corresponding thereto, or an average value of pixel values included in the difference image. 23. The image defect inspection apparatus according to claim 22, wherein a variance value, a maximum value, a minimum value, or an intermediate value or a difference between the maximum value and the minimum value is determined as the reference value.   The reference value determination unit includes an average value, a variance value, and a maximum value of pixel values included in the inspection partial image including the defect and / or a partial image including a pixel at the position of the defect in the reference image corresponding thereto. 23. The image defect inspection apparatus according to claim 22, wherein a value, a minimum value, or an intermediate value or a difference between the maximum value and the minimum value is determined as the reference value.   The reference value determining unit includes a partial image including a pixel at the position of the defect in the inspection partial image including the defect and a pixel at the position of the defect in the reference image corresponding to the inspection partial image. An average value, a variance value, a maximum value, a minimum value, or an intermediate value or a difference between the maximum value and the minimum value included in the difference image between the partial images is determined as the reference value. The image defect inspection apparatus according to claim 22. A defect detection condition determination unit for determining a detection threshold as the defect detection condition;
The defect detection condition determination unit determines the detection threshold for each inspection partial image based on a distribution of pixel value differences between corresponding pixels of the inspection partial image and the reference image,
The defect detection unit detects a difference between pixel values of corresponding pixels of the inspection partial image and the reference image, and when the difference exceeds the detection threshold, the pixel portion is regarded as the defect,
The image defect inspection apparatus according to claim 22, wherein the reference value determination unit determines the detection threshold as the reference value. A defect detection condition determination unit for determining a detection threshold as the defect detection condition;
The defect detection condition determining unit calculates a defect detection parameter for each inspection partial image based on a distribution of differences in pixel values between corresponding pixels of the inspection partial image and the reference image, and the defect detection parameter The detection threshold is determined according to
The defect detection unit detects a difference between pixel values of corresponding pixels of the inspection partial image and the reference image, and when the difference exceeds the detection threshold, the pixel portion is regarded as the defect,
The image defect inspection apparatus according to claim 22, wherein the reference value determination unit determines the defect detection parameter as the reference value.   The defect detection condition is reset so that the defect detection sensitivity is changed according to a variation between the reference values that are expected to be the same among the reference values determined in the image area. The image defect inspection apparatus according to claim 21. An image defect inspection apparatus that compares an inspection partial image obtained by dividing an inspection image obtained by imaging an inspection object with a reference image that should be essentially the same as the inspection partial image, and detects different portions as defects. An image defect inspection system comprising: a measurement device that measures a predetermined measurement value related to the inspection object used when the image defect inspection device defines the defect detection condition,
The image defect inspection apparatus includes:
A reference value determination unit that determines, for each region of a predetermined size on the inspection object, a reference value determined according to a predetermined determination method according to the predetermined measurement value measured by the measurement device in each region. When,
A distribution information determination unit that determines distribution information of the reference value determined for each of the predetermined size areas included in the macro area for a macro area configured to include a plurality of the predetermined size areas; With
An image defect inspection system, wherein defect detection is performed by changing defect detection conditions in accordance with the distribution information determined in the macro area. An image defect inspection apparatus that compares an inspection partial image obtained by dividing an inspection image obtained by imaging an inspection object with a reference image that should be essentially the same as the inspection partial image, and detects different portions as defects. An image defect inspection system comprising: a measurement device that measures a predetermined measurement value related to the inspection object used when the image defect inspection device defines the defect detection condition,
The measuring device determines, for each region of a predetermined size on the inspection object, a reference value determined according to a predetermined determination method according to the predetermined measurement value measured in each region, and the image Output to defect inspection equipment,
The image defect inspection apparatus, for a macro area configured to include a plurality of areas of the predetermined size, the reference value determined by the measurement apparatus for each area of the predetermined size included in the macro area An image defect inspection system, comprising: a distribution information determination unit that determines the distribution information of the image, and performing defect detection by changing a defect detection condition in accordance with the distribution information determined in the macro area. An image defect inspection apparatus that compares an inspection partial image obtained by dividing an inspection image obtained by imaging an inspection object with a reference image that should be essentially the same as the inspection partial image, and detects different portions as defects. An image defect inspection system comprising: a measurement device that measures a predetermined measurement value related to the inspection object used when the image defect inspection device defines the defect detection condition,
The measuring device is
A reference value determination unit that determines a reference value determined according to a predetermined determination method for each of a predetermined size area on the inspection object, according to the predetermined measurement value measured in each of these areas;
A distribution information determination unit that determines distribution information of the reference value determined for each of the predetermined size areas included in the macro area for a macro area configured to include a plurality of the predetermined size areas; The distribution information is output to the image defect inspection apparatus,
The image defect inspection apparatus performs defect detection by changing defect detection conditions in accordance with the distribution information determined in the macro area, which is input by the measurement apparatus.   35. The measurement apparatus according to any one of claims 32 to 34, wherein the measurement device includes an imaging unit that obtains a captured image obtained by imaging the inspection target, and the pixel value of the captured image is set as the measurement value. Image defect inspection system.   The measuring apparatus includes a film thickness measuring unit that measures the film thickness of a film formed on the surface of the semiconductor wafer to be inspected, and measures each area of the semiconductor wafer with the predetermined size. 35. The image defect inspection system according to claim 32, wherein the measured film thickness is used as the measurement value.   The measuring apparatus includes a dimension measuring unit that measures a critical dimension of a pattern formed on the surface of the semiconductor wafer to be inspected, and the measurement is performed in each region of the predetermined size of the semiconductor wafer. 35. The image defect inspection system according to claim 32, wherein a critical dimension is the measurement value. In the image defect inspection method for comparing the inspection partial image obtained by dividing the inspection image obtained by imaging the inspection object with a reference image that should be essentially the same as the inspection partial image, and detecting different portions as defects,
For each area of a predetermined size on the inspection target, according to the pixel value of the pixel included in the image obtained by imaging each of these areas, respectively determine a reference value determined according to a predetermined determination method,
For a macro area configured to include a plurality of areas of the predetermined size, determine the distribution information of the reference value determined for each area of the predetermined size included in the macro area,
An image defect inspection method, wherein defect detection is performed by changing defect detection conditions in accordance with the distribution information determined in the macro area.   39. The image defect inspection method according to claim 38, wherein the reference value is determined for each image block obtained by dividing the inspection image by a predetermined size.   The image defect inspection method according to claim 39, wherein the reference value is determined for each image block in accordance with a pixel value of a pixel existing at a predetermined position in the pixel block.   For each image block, an average value, a variance value, a maximum value, a minimum value, or an intermediate value or a difference between the maximum value and the minimum value of the pixels included in the image block, or the image block and the image The average value, variance value, maximum value, minimum value, or intermediate value or difference between the maximum value and minimum value of the pixel values of the pixels included in the difference image between the reference image to be compared with the block, the reference value The image defect inspection method according to claim 39, wherein the image defect inspection method is determined as follows.   The defect detection condition is changed by changing a defect detection sensitivity according to a variation between the reference values that are supposed to be the same among the reference values included in the distribution information. Item 42. The image defect inspection method according to any one of Items 39 to 41.   The image defect according to any one of claims 39 to 41, wherein the defect detection condition is changed by changing a defect detection sensitivity according to the distribution information determined as a dispersion value of the reference value. Inspection method. Determining the defect detection conditions;
Detecting a difference between pixel values of corresponding pixels of the inspection partial image and the reference image, and detecting the pixel portion as a defect when the difference satisfies the defect detection condition;
The defect detection condition in each macro area is reset according to the distribution information determined in each macro area, and the defect detected in the macro area is output under the reset defect detection condition. The image defect inspection method according to any one of claims 39 to 41, wherein whether or not to perform the determination is determined.   The defect detection condition is reset so that the defect detection sensitivity decreases as the variation between the reference values that are originally supposed to be the same among the reference values included in the distribution information increases. The image defect inspection method according to claim 44, wherein: Determining the distribution information as a variance of the reference value;
45. The image defect inspection method according to claim 44, wherein the defect detection condition is reset so that the defect detection sensitivity decreases as the distribution information increases. A detection threshold as the defect detection condition is determined for each inspection partial image according to a predetermined determination method based on a distribution of pixel value differences between corresponding pixels of the inspection partial image and the reference image,
Detecting a difference between pixel values of corresponding pixels of the inspection partial image and the reference image, and detecting the pixel portion as a defect when the difference exceeds the detection threshold;
40. The image defect inspection method according to claim 39, wherein the detection threshold is determined as the reference value. For each inspection partial image, a defect detection parameter is calculated according to a predetermined calculation method based on a distribution of pixel value differences between corresponding pixels of the inspection partial image and the reference image, and according to the defect detection parameter , Determining a detection threshold as the defect detection condition,
Detecting a difference between pixel values of corresponding pixels of the inspection partial image and the reference image, and detecting the pixel portion as a defect when the difference exceeds the detection threshold;
40. The image defect inspection method according to claim 39, wherein the defect detection parameter is determined as the reference value.   40. The image defect inspection method according to claim 39, wherein one inspection partial image, which is an image comparison unit, is used as a unit of the image block.   40. An image of one of a plurality of chips formed on the surface of the semiconductor wafer of the inspection image obtained by imaging the surface of the semiconductor wafer to be inspected is used as a unit of the image block. An image defect inspection method described in 1.   A unit of the image block is an image in a range exposed by one reticle shot of the inspection image obtained by imaging the surface of the semiconductor wafer on which a pattern is formed in the lithography process to be inspected. The image defect inspection method according to claim 39. Defect detection conditions are determined according to the distribution information determined in the macro region,
The image defect inspection method according to claim 38, wherein when the comparison result of the inspection partial image and the reference image satisfies the defect detection condition, different portions are detected as defects.   53. The image defect inspection method according to claim 52, wherein the reference value is determined according to a pixel value of a pixel that is a captured image to be inspected and is included in a captured image different from the inspection image.   The image defect inspection method according to claim 53, wherein the captured image is an image obtained by thinning out pixels of the inspection image.   The image defect inspection method according to claim 53, wherein the captured image is an image captured at a lower magnification than capturing the inspection image.   53. The image defect inspection method according to claim 52, wherein the distribution information is determined for another macro area in parallel with detecting a defect for one macro area on the inspection target.   57. The image defect inspection method according to claim 56, wherein the image pickup device is picked up by an image pickup device different from the image pickup device picking up the inspection image. This is an image defect inspection method in which an inspection partial image obtained by dividing an inspection image obtained by imaging an inspection object is compared with a reference image that should originally be the same as the inspection partial image, and different portions are detected as defects. And
For each area of a predetermined size on the inspection object, measure a predetermined measurement value related to the inspection object in each of these areas,
According to the measured value measured, determine a reference value determined according to a predetermined determination method,
For a macro area configured to include a plurality of areas of the predetermined size, determine the distribution information of the reference value determined for each area of the predetermined size included in the macro area,
An image defect inspection method, wherein defect detection is performed by changing defect detection conditions in accordance with the distribution information determined in the macro area.   59. The image defect inspection method according to claim 58, wherein the inspection object is imaged, and a pixel value of the captured image is used as the measurement value.   A film thickness of a film formed on the surface of the semiconductor wafer is measured for each area of the predetermined size of the semiconductor wafer to be inspected, and the film thickness value is set as the measured value. The image defect inspection method according to claim 58.   A critical dimension of a pattern formed on the surface of the semiconductor wafer is measured for each region of the predetermined size of the semiconductor wafer to be inspected, and the critical dimension is used as the measured value. The image defect inspection method according to claim 58. In the image defect detection method for comparing the inspection partial image obtained by dividing the inspection image into a plurality of inspection partial images and corresponding reference images that should be essentially the same, and detecting different portions as defects,
When the comparison result between the inspection partial image and the reference image satisfies a defect detection condition, a different part is detected as a defect,
For each of a plurality of locations on the inspection image, a predetermined reference value is determined according to a pixel value of a pixel determined corresponding to each location,
For the image area of a predetermined size determined in the inspection image, determine the distribution information of the reference value determined in the image area,
The defect detection condition is reset according to the distribution information determined for the image area, and the defect detection condition is reset to determine whether the defect detected in the inspection partial image included in the image area is output. Judging under
An image defect inspection method characterized by the above.   The image defect inspection method according to claim 62, wherein the reference value is determined for each of the locations where the defect is detected.   64. The image defect inspection method according to claim 63, wherein the image region is defined as a region larger than the inspection partial image. The inspection image is an image obtained by imaging a semiconductor wafer surface to be inspected,
64. The image defect inspection method according to claim 63, wherein the image area of the predetermined size is an area obtained by imaging the entire surface or a part of the semiconductor wafer.   A pixel value at a predetermined position in the inspection partial image including the defect and / or the reference image corresponding thereto, or an average value, a variance value, a maximum value, a minimum value of pixel values included in these images, or 64. The image defect inspection method according to claim 63, wherein an intermediate value or a difference between the maximum value and the minimum value is determined as the reference value.   A pixel value at a predetermined position in the difference image between the inspection partial image including the defect and the reference image corresponding thereto, or an average value, a variance value, a maximum value of the pixel values included in the difference image, 64. The image defect inspection method according to claim 63, wherein a minimum value or an intermediate value or a difference between the maximum value and the minimum value is determined as the reference value.   Average value, variance value, maximum value, minimum value of pixel values included in the inspection partial image including the defect and / or the partial image including the pixel at the position of the defect in the reference image corresponding thereto, or these 64. The image defect inspection method according to claim 63, wherein an intermediate value or a difference between a maximum value and a minimum value is determined as the reference value.   The difference between the partial image including the pixel at the position of the defect in the inspection partial image including the defect and the partial image including the pixel at the position of the defect in the reference image corresponding to the inspection partial image 64. The average value, variance value, maximum value, minimum value, or intermediate value or difference between the maximum value and minimum value of pixel values included in an image is determined as the reference value. Image defect inspection method. For each of the inspection partial images, the detection threshold is determined based on a distribution of pixel value differences between corresponding pixels of the inspection partial image and the reference image,
Detecting a difference between pixel values of corresponding pixels of the inspection partial image and the reference image, and detecting the pixel portion as the defect when the difference exceeds the detection threshold;
64. The image defect inspection method according to claim 63, wherein the detection threshold is determined as the reference value. For each inspection partial image, a defect detection parameter is calculated based on a difference distribution of pixel values between corresponding pixels of the inspection partial image and the reference image, and the detection threshold is determined according to the defect detection parameter. ,
Detecting a difference between pixel values of corresponding pixels of the inspection partial image and the reference image, and detecting the pixel portion as the defect when the difference exceeds the detection threshold;
64. The image defect inspection method according to claim 63, wherein the defect detection parameter is determined as the reference value.   The defect detection condition is reset so that the defect detection sensitivity is changed according to a variation between the reference values that are expected to be the same among the reference values determined in the image area. The image defect inspection method according to claim 62.

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