JP4554663B2 - Pattern inspection apparatus and pattern inspection method - Google Patents

Description

  The present invention relates to an inspection for inspecting a pattern of a sample to be inspected, and in particular, an inspection apparatus and an inspection for inspecting a pattern of a photomask, a wafer, or a liquid crystal substrate used when manufacturing a semiconductor element or a liquid crystal display (LCD). It is about the method.

  As represented by a 1 gigabit class DRAM, a pattern constituting a large scale integrated circuit (LSI) is going to be on the order of submicron to nanometer. One of the major causes of a decrease in yield in the manufacture of LSI is a defect of a photomask used when an ultrafine pattern is exposed and transferred onto a semiconductor wafer by a photolithography technique. In particular, with the miniaturization of the pattern dimensions of LSIs formed on semiconductor wafers, the dimensions that must be detected as pattern defects have become extremely small. For this reason, an apparatus for inspecting such a defect has been developed.

On the other hand, with the development of multimedia, liquid crystal display devices (LCDs) are increasing in size of the liquid crystal substrate to 500 mm × 600 mm or more and miniaturization of patterns such as TFTs formed on the liquid crystal substrate. Progressing. Therefore, it is required to inspect a very small pattern defect over a wide range. For this reason, there is an urgent need to develop a sample inspection apparatus for efficiently inspecting defects of a photomask used in manufacturing such a large area LCD pattern and a large area LCD in a short time. In the conventional apparatus, when a comparison image based on design data is generated, a fixed-value image is generated even in an area where the design data does not exist, which is sufficient when the capacity of the design data increases locally. There is a problem that the inspection cannot be executed at a high speed (see Patent Document 1).
JP-A-10-141932

(1) An object of the present invention is to increase the inspection speed of a pattern of a sample to be inspected.
(2) Further, the present invention is to enable inspection of a pattern defect of a sample to be inspected at high speed.

(1) In the embodiment of the present invention, a measurement data generation unit that generates measurement data corresponding to the pattern of the sample to be measured , and the presence or absence of a figure based on the design data of the sample to be measured before generating the image data detecting, as a result of the detection, by omitting the image data generation regions figure does not exist, the image data generation unit that forms the raw image data based on the design data to a region shape is present, on the image data and the figure presence information storage unit for storing information of the presence or absence of shapes, a comparison processing unit for comparing the measurement data and image data, Ru provided with, in the pattern inspection apparatus. If the difference between the measurement data and the image data exceeds a threshold value, it is determined as a defect .
(2) In the embodiment of the present invention, measurement data corresponding to the pattern of the sample to be measured is generated, the presence or absence of a figure on the design data of the sample to be measured is detected before the image data is generated, and the detection result , skip image data generation regions figure does not exist, generates image data based on the design data of the sample to a region shape is present, the measurement data for the area in which FIG type is present The pattern inspection method compares the generated image data with each other, compares the measured data with a specific fixed value for an area where no figure exists, and determines that the defect is a defect if the difference exceeds a threshold value.

  Hereinafter, inspection of a pattern of a sample to be inspected according to an embodiment of the present invention will be described.

(Pattern inspection device)
FIG. 1 is a block diagram illustrating a pattern inspection apparatus 10 according to an embodiment of the present invention. The pattern inspection apparatus 10 inspects a pattern 12 of a sample to be measured such as a mask. The pattern inspection apparatus 10 generates the measurement data 16 by measuring the pattern 12 of the sample to be measured by the measurement data generation unit 14. Then, the pattern inspection apparatus 10 generates image data 26 by processing the design data 20 of the pattern 12 of the sample to be measured by the image data generation unit 22. At this time, the image data generation unit 22 detects a region where a graphic exists in the design data 20, that is, a region where a graphic exists, and a region where a graphic does not exist, that is, a region where no graphic exists. Store in the storage unit 24. The pattern inspection apparatus 10 compares the measurement data 16 generated by the measurement data generation unit 14 with the image data 26 generated by the image data generation unit 22 by the comparison processing unit 18 to detect defects in the pattern 12 of the sample to be measured. . The pattern inspection apparatus 10 uses the graphic presence / absence information of the design data 20 to generate the image data 26 only from the design data 20 in the area where the graphic exists, and omits the generation of the image data 26 of the unnecessary area. The effective generation speed of the image data 26 can be increased, and the execution speed of pattern inspection can be increased. The image data generation unit 22 includes an image creation unit 220 that creates the original image data 260 from the design data 20, a figure presence / absence detection unit 222 that detects the presence / absence of a figure, and an output unit 224 that outputs various data to each processing unit. A filter processing unit 226 that filters the original image data 260 transferred from the output unit 224 to generate image data 26 is provided.

  FIG. 2 is a conceptual diagram showing the internal configuration of the pattern inspection apparatus 10. The pattern inspection apparatus 10 uses a substrate such as a mask or a wafer as a sample 100 to be measured, and inspects a pattern defect of the sample 100 to be measured. The pattern inspection apparatus 10 includes an optical image acquisition unit 110 and a control system circuit 150. The optical image acquisition unit 110 includes an autoloader 112, an illumination device 114 that generates illumination light, an xyθ table 116, an xyθ motor 118, a laser length measurement system 120, a magnifying optical system 122, a piezo element 124, and a light receiving unit 126 such as a photodiode array. Sensor circuit 128 and the like. In the control system circuit 150, a CPU 152 serving as a control computer is connected to a mass storage device 156, a memory device 158, a display device 160, a printing device 162, an autoloader control circuit 170, a table control circuit via a bus 154 serving as a data transmission path. 172, an autofocus control circuit 174, a development circuit 176, a reference circuit 178, a comparison circuit 180, a position circuit 182 and the like. The expansion circuit 176, the reference circuit 178, the comparison circuit 180, and the position circuit 182 are connected to each other as shown in FIG. The xyθ table 116 is driven by an xyθ motor 118 such as an x-axis motor, a y-axis motor, and a θ-axis motor.

  The measurement data generation unit 14 can be configured by the optical image acquisition unit 110. The image creation unit 220 of the image data generation unit 22 can be configured by the development circuit 176, and the filter processing unit 226 can be configured by the reference circuit 178. The comparison processing unit 18 can be configured by a comparison circuit 180. The graphic presence / absence information storage unit 24 can be configured by a memory device 158. In FIG. 2, description of components other than those necessary for describing the present embodiment is omitted. It goes without saying that the pattern inspection apparatus 10 usually includes other necessary configurations.

  The measurement data 16 can be acquired by the optical image acquisition unit 110 as follows. The sample 100 to be measured is placed on an xyθ table 116 provided so as to be movable in the horizontal and rotational directions by the xyθ axis motor 118. The sample to be measured 100 is irradiated with light by the illumination device 114. Below the sample 100 to be measured, an magnifying optical system 122, a light receiving unit 126, and a sensor circuit 128 are arranged. Light that has passed through the sample 100 to be measured, such as an exposure mask, forms an optical image on the light receiving unit 126 via the magnifying optical system 122 and is incident thereon. The autofocus control circuit 174 controls the piezo element 124 in order to absorb the deflection of the sample 100 to be measured and the change in the z-axis (orthogonal to the x-axis and y-axis) direction of the xyθ table 116, thereby measuring the sample to be measured. Focus to 100. The optical image received by the light receiving unit 126 is sent to the comparison circuit 180 as measurement data by the sensor circuit 128. 2 uses the transmitted light of the sample 100 to be measured, the reflected light of the sample 100 to be measured can also be used.

  FIG. 3 is a diagram for explaining an optical image acquisition procedure. As shown in FIG. 3, the inspection region of the sample 100 to be measured is virtually divided by the scan width W in the y-axis direction (y is an axis of coordinates and is a lowercase letter). That is, the inspection area is virtually divided into a plurality of strip-shaped inspection stripes 101 having a scan width W. Further, the xyθ table 116 is controlled so that the divided inspection stripes 101 are continuously scanned. The xyθ table 116 moves along the x-axis (x indicates a coordinate axis and is a lower case letter), and an optical image is acquired as the inspection stripe 101. In FIG. 3, the inspection stripe 101 has a rectangular shape having a scan width W in the y-axis direction and a longitudinal direction having a length in the x-axis direction. The light receiving unit 126 continuously receives images with a scan width W as shown in FIG. After acquiring the image in the first inspection stripe 101, the light receiving unit 126 continuously inputs the image having the scan width W while moving the image in the second inspection stripe 101 in the opposite direction. The scan width W is about 2048 pixels, for example. When acquiring an image in the third inspection stripe 101, the image is moved in the direction opposite to the direction in which the image in the second inspection stripe 101 is acquired, that is, in the direction in which the image in the first inspection stripe 101 is acquired. Get an image.

  The pattern image formed on the light receiving unit 126 is photoelectrically converted and further A / D (analog / digital) converted by the sensor circuit 128. The light receiving unit 126 is provided with sensors such as a photodiode array and a TDI (time delay integrator) sensor. By continuously moving the xyθ table 116 serving as a stage in the x-axis direction, the TDI sensor images the pattern of the sample 100 to be measured. The optical image acquisition unit 110 includes the illuminating device 114, and the magnification optical system 122, the light receiving unit 126, and the sensor circuit 128 constitute a high-magnification inspection optical system.

  The xyθ table 116 is driven by the table control circuit 172 under the control of the CPU 152. It can be moved by a drive system such as a three-axis (xy-θ) motor 118 driven in the x-axis direction, the y-axis direction, and the θ-direction. As these x motor, y motor, and θ motor, for example, a step motor can be used. The movement position of the xyθ table 116 is measured by the laser length measurement system 120 and supplied to the position circuit 182. The sample 100 to be measured on the xyθ table 116 is automatically transported from the autoloader 112 driven by the autoloader control circuit 170, and is automatically discharged after the inspection is completed.

  The measurement data 16 of the optical image of the sample 100 to be measured output from the sensor circuit 128 is sent to the comparison circuit 180 together with the data indicating the position of the sample 100 to be measured on the xyθ table 116 output from the position circuit 182. The measurement data 16 is, for example, 8-bit unsigned data, and represents the brightness gradation of each pixel.

  On the other hand, the design data 20 used when forming the pattern of the sample 100 to be measured is stored in the mass storage device 156. The design data 20 is input from the mass storage device 156 to the expansion circuit 176 through the CPU 152. As a design data development process, the development circuit 176 converts the design data of the sample 100 to be measured into binary or multivalued original image data 260, and the original image data 260 is sent to the reference circuit 178. Then, the reference circuit 178 performs an appropriate filter process on the original image data 260 to generate the image data 26. It can be said that the measurement data 16 as an optical image obtained from the sensor circuit 128 is in a state in which a filter is activated by the resolution characteristic of the magnifying optical system 122, the aperture effect of the light receiving unit 126, and the like. In this state, there is a difference between the characteristics of the two, so that the original image data 260 on the design side can be matched with the measurement data 16 by performing the filtering process by the reference circuit 178. As a comparison processing step, the comparison circuit 180 takes in the measurement data 16 obtained from the sample 100 to be measured and the image data 26 generated by the development circuit 176 and the reference circuit 178, compares them according to a predetermined algorithm, Determine if there is a defect.

  In the above description, what is described as “˜circuit” or “˜process” can be configured by a computer-operable program. Or you may make it implement by not only the program used as software but the combination of hardware and software. Alternatively, a combination with firmware may be used. When configured by a program, the program is recorded on a recording medium such as a magnetic disk device, a magnetic tape device, an FD, or a ROM (Read Only Memory). For example, the table control circuit 172, the expansion circuit 176, the reference circuit 178, the comparison circuit 180, and the like that constitute the arithmetic control unit may be configured as electrical circuits, or realized as software that can be processed by the CPU 152. May be. Moreover, you may implement | achieve with the combination of an electrical circuit and software.

  The embodiments have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. In each embodiment, the inspection position is scanned by moving the xyθ table 116, but the xyθ table 116 may be fixed and other optical systems may be moved. That is, relative movement may be performed. In addition, although descriptions are omitted for parts and the like that are not directly required for the description of the present invention, such as a device configuration and a control method, a required device configuration and a control method can be appropriately selected and used. In addition, all pattern inspection apparatuses 10 that include the elements of the present invention and whose design can be changed as appropriate by those skilled in the art are included in the scope of the present invention.

(First embodiment)
The comparison processing unit 18 first cuts the measurement data 16 and the image data 26 into areas having appropriate pixel sizes. The pixel size area is cut out to a predetermined length in the x-axis direction of the stripe 101 having the scan width W, for example. Usually, prior to the inspection, the measurement data 16 and the image data 26 are aligned (overall alignment). This is performed using an appropriate dedicated mark, but may be performed using an arbitrary pattern edge or the like designated by the operator. The image data 26 is appropriately filtered by the filter processing unit 226 before being processed by the comparison processing unit 18. There are various levels of filter processing for the image data 26, and at which stage it is determined as appropriate.

  Although the approximate positions of the cut out measurement data 16 and the image data 26 are in alignment, there is a slight displacement due to the distortion of the sample, the accuracy of the xyθ table 116, and the like. Therefore, the amount of positional deviation between the cut-out images is measured in sub-pixel units and adjusted so that the amount of deviation between the two becomes small (area alignment processing), and then compared according to an appropriate algorithm, The presence or absence of a pattern defect is determined.

  In the first embodiment, as shown in FIG. 4, an X of a certain figure is compared with the design data 20 in which the figure is aligned at the start coordinate of the figure with respect to the moving direction of the stage, that is, the longitudinal direction of the inspection stripe 101. The region from the start coordinate indicated by Xe to the end coordinate indicated by Xe ′ is determined as a region 204 with a figure, and if the end coordinate of one graphic is separated from the start coordinate of the next graphic and does not overlap, start from the end coordinate The coordinates up to the coordinates are determined as a region 202 without a figure. The graphic presence / absence information is stored in the graphic presence / absence information storage unit 24 as a result of determination in units of lines. When two or more plural figures partially overlap in the longitudinal direction of the inspection stripe 101, the area 204 with the figure is obtained up to the largest end coordinate among the end coordinates of the figure overlapping the start coordinates of the first figure. Is determined. Here, the start coordinate X and the end coordinate Xe ′ indicate the position coordinate in the x-axis direction, that is, the position coordinate in the longitudinal direction of the inspection stripe 101. The generated image is typically a rectangle of 2048 pixels (width) × several megapixels (length). Among these, the number of pixels (the number of sets of 2048 pixels) in the longitudinal direction of the rectangle (that is, the image acquisition direction or the x direction) is called the number of lines (for example, several megapixels). For example, one piece of information is attached to a set of 2048 pixels, that is, one longitudinal length. The x-axis direction is a direction in which images are continuously taken, and is a longitudinal direction of several mega of a 2048 × several mega pixel image. In the determination of the presence / absence of a graphic, it is checked whether or not pixels in line units, for example, 2048 pixels, form part of the graphic pattern in the design data. This check is performed in the image acquisition direction, and in the image acquisition direction (the x direction or the longitudinal direction of the stripe), it is determined that there is a figure on the design data, and there is a figure on the design data. The area not to be used is determined as having no figure.

FIG. 5 shows a method for detecting the presence or absence of a figure in the design data 20. First, in the direction in which the measurement data generation unit 14 generates measurement data (that is, the x direction), the presence or absence of a graphic on the design data is detected, and the start point of the inspection stripe 101 where there is no graphic in the x-axis direction is detected by Xe (pointer And initialization is performed by substituting 0 into Xe (step S1). Next, the extracted from the design data 20 of figure substitutes start point x ₀ of a portion of graphics on X (pointer). When the figure does not overlap in the x-axis direction as shown in FIG. 4, the length lx of the figure in the x-axis direction is substituted into Lx (pointer) (step S2). The region from Xe to X is determined as a region 202 without a graphic (step S3). The value of X + Lx is substituted for Xe ′ (step S4). The area from X to Xe ′ is determined to be an area 204 with a figure, and information about the presence / absence of a figure is stored in the figure presence / absence information storage unit 24 (step S5). Next, Xe ′ is substituted for Xe in order to determine whether or not there is a graphic in another area in the x-axis direction (step S6). The image data 26 is generated for the area 204 with a graphic, and the image data 26 is not generated for the area 202 without a graphic (step S7).

(Second Embodiment)
FIG. 6 shows an example in which the image data generation unit 22 converts only a region 204 having a figure in the design data 20 into binary or multivalued image data 26. FIG. 6 (A) is represented by a drawing on the assumption that the design data 20 has been developed. FIG. 6B is a drawing of the original image data 260 in which the design data 20 is expanded, and shows a state in which information on the presence / absence of a graphic is stored in the graphic presence / absence information storage unit 24. The original image data 260 is the image data 26 before the filtering process. FIG. 6C shows image data 26 to be compared in the comparison processing unit 18.

  The image data generation unit 22 develops the design data 20 by the image creation unit 220 to create original image data 260, determines the presence / absence of a graphic by the graphic presence / absence detection unit 222, and outputs the original image data 260 by the output unit 224. The data is output from the image creation unit 220 to the filter processing unit 226. The original image data 260 is filtered by the filter processing unit 226 to become image data 26. Note that the output unit 224 can output data to an internal processing unit such as the filter processing unit 226 in the image data generation unit 22, or can output data to an external processing unit such as the comparison processing unit 18. Here, the graphic presence / absence detection unit 222 detects the presence / absence of a graphic on the image data in the direction in which the measurement data generation unit 14 generates the measurement data (that is, the x direction).

  The image data generation unit 22 determines the presence / absence of graphic information from the design data 20 by the same method as in the first embodiment, and creates original image data 260 for the area 204 with a graphic. The binary bit flag is set to 1 in the figure presence / absence information storage unit 24 for the area 204 with a figure. In the case of the region 202 without a graphic, the original image data 260 is not created, and the binary bit flag is set to 0 and stored in the graphic presence / absence information storage unit 24. However, the value of the binary bit flag is not limited to the above value. The original image data 260 is sent to the filter processing unit 226 as necessary to be subjected to filter processing.

  At that time, if the graphic presence / absence information storage unit 24 includes information on the presence of a graphic in the original image data 260, the image data generation unit 22 transmits the original image data 260 of the area 204, and the graphic presence / absence information storage unit 24 When there is no information, a fixed value designated in advance is transmitted. Alternatively, when the filtered image data 26 is output to the comparison circuit 180, if there is information with a graphic in the graphic presence / absence information storage unit 24, the image data 26 of the region 204 is transmitted, and the graphic presence / absence information storage unit When there is information without a graphic in 24, a fixed value designated in advance is transmitted. As a result, a fixed value is entered in the area 202 without a figure in FIG. As a result, it is possible to perform the conversion process into the image data 26 only in the area that needs to be compared, the conversion time of the image data 26 can be shortened, and the high-speed pattern inspection can be executed.

(Third embodiment)
FIG. 7 is a diagram for explaining the third embodiment, and FIGS. 7A to 7C correspond to FIGS. 6A to 6C of the second embodiment. In the second embodiment, when the original image data 260 is output to the filter processing unit 226, a fixed value is output for the data in the area 202 without a graphic, as shown in FIG. 7B. It is determined that there is graphic information, and only the area 204 where the original image data 260 is generated is transferred to the filter processing unit 226, and only the bit flag is transmitted for the area 202 where the original image data 260 is not generated. . Thereafter, the filter processing unit 226 treats the area that has received only the bit flag as having received a fixed value, and applies appropriate filter processing, so that one line of transfer data, typically 2048 bytes, is converted to 1 It can be reduced to bit flags of bits. Alternatively, in the second embodiment, when the image data 26 is output from the image data generation unit 22 to the comparison processing unit 18, a fixed value is output. However, only the area where the image data 26 is generated is included in the image data 26. Transfer is performed, and only bit flags are transmitted for areas not generated. Thereafter, the comparison processing unit 18 treats the area receiving only the bit flag as having received a fixed value, and performs a comparison test. Thereby, in addition to shortening the conversion time of the image data 26, the transfer time of the image data 26 can be reduced, and high-speed inspection can be executed.

(Fourth embodiment)
FIG. 8 is a diagram for explaining the fourth embodiment, and FIGS. 8A to 8C correspond to FIGS. 7A to 7C of the third embodiment. In the third embodiment, when the original image data 260 is output to the filter processing unit 226, only the bit flag is transmitted for the data of the area 202 without the graphic, but according to the coordinate value of the graphic according to FIG. As a result of determining the presence / absence of graphic information, coordinate value data (1, 2, 3,...) For the area 204 in which the graphic information is determined as shown in FIG. ..) And the original image data 260 and the stored coordinate value data (1, 2, 3,...) Are transferred to the filter processing unit 226 only in the region 204 determined to have graphic information. The area received by the filter processing unit 226 becomes discontinuous, and the area determined not to be received can be treated as a fixed value by the same effect as in the third embodiment. , The transfer time can also be reduced, it is possible to perform a high-speed inspection. Alternatively, in the third embodiment, when outputting the image data 26 to the comparison processing unit 18, only the flag is transmitted for the data in the area 202 without the graphic, but there is graphic information as shown in FIG. 8. The coordinate value data (1, 2, 3,...) Relating to the longitudinal direction of the inspection stripe 101 in the area is stored in the area 204 determined as “image”, and only the area 204 determined as having graphic information is imaged. The data 26 and the stored coordinate value data (1, 2, 3,...) Are transferred to the comparison processing unit 18, and the coordinates received by the comparison processing unit 18 are discontinuous, and the area determined not to be received. With respect to the above, even if the comparison inspection is performed as a fixed value, the transfer time can be reduced and the inspection can be performed at a high speed by the same effect as in the third embodiment.

  In the conventional apparatus, when a comparison image based on the design data 20 is generated, a fixed-value image is generated even in the area 202 where the graphic of the design data 20 does not exist, so the capacity of the design data 20 is increased. In some cases, the inspection cannot be performed at a sufficient speed. However, according to the embodiment of the present invention, the conversion time of the image data 26 can be shortened by generating an image based on the design data only in a necessary area. In addition, the data transfer time can be reduced, and high-speed inspection can be executed even for a large amount of data.

  Since various combinations other than the above embodiment can be considered, it goes without saying that the present invention is not limited to the embodiment described here.

It is a figure which shows the apparatus and method of pattern inspection in embodiment. It is a conceptual diagram which shows the internal structure of the pattern inspection apparatus in embodiment. It is a figure for demonstrating the acquisition procedure of an optical image. It is a figure for demonstrating the design data of the pattern of a to-be-measured sample. It is a figure explaining the procedure which extracts graphic information from design data. It is explanatory drawing which produces image data from design data. It is another explanatory drawing which creates image data from design data. It is another explanatory drawing which creates image data from design data.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Pattern inspection apparatus 12 ... Pattern 14 of measured sample ... Measurement data generation part 16 ... Measurement data 18 ... Comparison processing part 20 ... Design data 22 of measured sample pattern ... Image data generation unit 220... Image creation unit 222... Graphic presence / absence detection unit 224... Output unit 226. Image data 100, Sample to be measured 101, Inspection stripe 110, Optical image acquisition unit 112, Autoloader 114, Illumination device 116, xyθ table 118, xyθ motor 120, Laser length measurement system 122, Enlargement Optical system 124 .. Piezo element 126 .. Light receiving unit 128 .. Sensor circuit 150 .. Control system circuit 152 .. CPU
154 ·· Bus 156 · · Mass storage device 158 · · Memory device 160 · · Display device 162 · · Printing device 170 · · Autoloader control circuit 172 · · Table control circuit 174 · · Autofocus control circuit 176 · · Expansion circuit 178 ··· Reference circuit 180 · · Comparison circuit 182 · · Position circuit 200 · · Figure 202 · · Region 204 without figure · · Region with figure

Claims (5)

A measurement data generation unit that generates measurement data corresponding to the pattern of the sample to be measured;
Before the image data is generated, the presence or absence of a figure is detected based on the design data of the sample to be measured , and as a result of the detection, the image data generation of the area where the figure does not exist is omitted, and the area where the figure exists an image data generation unit that forms the raw image data based on the design data,
A graphic presence / absence information storage unit for storing information on the presence / absence of a graphic on the image data;
A pattern inspection apparatus comprising: a comparison processing unit that compares measurement data and image data. The pattern inspection apparatus according to claim 1,
Image data generation unit, to the area where there is the graphic on the design data to generate the image data, and outputs, to the region that does not generate image data, and outputs the pre-specified value, Pattern inspection device. The pattern inspection apparatus according to claim 1,
Image data generation unit, to the area where there is the graphic on the design data to generate the image data, and outputs, to the region that does not generate image data, information that does not generate image data Is a pattern inspection device. The pattern inspection apparatus according to claim 1,
Image data generation unit, to the area where there is the graphic on the design data, the generated image data, and outputs the coordinates to the image data, the pattern inspection apparatus. Generate measurement data corresponding to the pattern of the sample to be measured,
Before generating image data, detect the presence of figures on the design data of the sample to be measured,
As a result of detection, the image data generation of the area where the figure does not exist is omitted, and the image data is generated based on the design data of the sample to be measured for the area where the figure exists ,
For regions where FIG type is present by comparing the image data generated with the measured data, it determines that the measured data to a region shape is not present by comparing the fixed value, the defect Once difference exceeds the threshold value A pattern inspection method.

Images