JP2020085527A - Pattern inspection device and pattern inspection method - Google Patents

Abstract

PURPOSE: To provide an inspection device with which it is possible to reduce an increase in inspection time even when the data volume of defective spots is large.CONSTITUTION: A pattern inspection device in one embodiment of the present invention comprises: an optical image acquisition mechanism for acquiring optical images of a plurality of areas from a substrate on which a plurality of graphic patterns are formed; a plurality of comparison units for executing, using a plurality of reference images corresponding to the optical images of the plurality of areas, the process of comparing the corresponding optical images and reference images in parallel between at least some areas of the plurality of areas; at least one defect information generation unit for generating defect information on the basis of transferred data upon transfer of defective image data determined as defective; and a transfer unit for determining the order and timing of transfer of detective image data depending on the generation processing status of the defect information.SELECTED DRAWING: Figure 1

Description

The present invention relates to a pattern inspection device and a pattern inspection method. For example, regarding a pattern inspection technique for inspecting pattern defects of an object which is a sample used for semiconductor manufacturing, an extremely small pattern such as a photomask, a wafer, or a liquid crystal substrate used when manufacturing a semiconductor element or a liquid crystal display (LCD). To inspect for defects.

2. Description of the Related Art In recent years, circuit line widths required for semiconductor devices have become narrower with higher integration and larger capacity of large scale integrated circuits (LSI). In these semiconductor elements, an original image pattern (also referred to as a mask or reticle; hereinafter referred to as a mask) on which a circuit pattern is formed is exposed and transferred onto a wafer by a reduction projection exposure apparatus called a stepper. It is manufactured by forming a circuit. Therefore, in manufacturing a mask for transferring such a fine circuit pattern onto a wafer, a pattern drawing apparatus using an electron beam capable of drawing a fine circuit pattern is used. A pattern circuit may be directly drawn on the wafer by using such a pattern drawing apparatus. Alternatively, attempts have been made to develop a laser beam drawing apparatus that draws using a laser beam other than an electron beam.

Further, improvement in yield is indispensable for manufacturing an LSI that requires a large manufacturing cost. However, as represented by a 1-gigabit class DRAM (random access memory), patterns constituting an LSI are going to be in the order of submicrons to nanometers. One of the major factors that reduce the yield is a pattern defect of a mask used when exposing and transferring an ultrafine pattern on a semiconductor wafer by a photolithography technique. In recent years, with the miniaturization of the LSI pattern size formed on a semiconductor wafer, the size that must be detected as a pattern defect has become extremely small. Therefore, it is necessary to improve the accuracy of the pattern inspection device for inspecting the defects of the transfer mask used in the LSI manufacturing.

As an inspection method, compare the optical image of the pattern formed on the sample such as the lithography mask at a predetermined magnification with the magnifying optical system with the design data or the optical image of the same pattern on the sample. A method of performing an inspection by doing is known. For example, as a pattern inspection method, a "die to die (die-to-die) inspection" in which optical image data obtained by imaging the same pattern at different locations on the same mask is compared, or a pattern is designed using CAD data as a mask. The drawing data (design data) converted into the device input format for the drawing device to input at the time of drawing is input to the inspection device, a design image (reference image) is generated based on this, and the pattern and the pattern are imaged. There is a "die to database (die-database) inspection" in which an optical image serving as measurement data is compared. In the inspection method in such an inspection apparatus, the sample is placed on the stage, and the light beam scans the sample by the movement of the stage to perform the inspection. A light source and an illumination optical system illuminate the sample with a light beam. The light transmitted or reflected by the sample is imaged on the sensor via the optical system. The image captured by the sensor is sent to the comparison circuit as measurement data. In the comparison circuit, after the images are aligned with each other, the measurement data and the reference data are compared according to an appropriate algorithm, and if they do not fall within the allowable range, it is determined that there is a pattern defect.

When a defect is detected, the image data including the defect and the defect position specifying information are combined and output so as to be visually recognized by the user. Then, the user identifies the status of the defect by confirming the combined information. Here, with the recent miniaturization of patterns, the inspection apparatus has come to detect a huge number of defects as compared with the conventional one. Therefore, it becomes necessary to transfer the data regarding the defect, which has become large in capacity with the increase in the number of defects, between the data processing circuits. In the case of the conventional case where the number of defects is small, the same data processing as the conventional case is performed. There is a problem that the inspection time is significantly increased as compared with the above. Therefore, it is required to reduce the increase in inspection time as much as possible.

Here, the coordinates of the representative pixel of the defect candidate determined by the image comparison are stored in the storage device, and when the capacity of the storage device overflows, the inspection is stopped and the inspection threshold value is changed to determine the number of defects. A technique is disclosed in which the determination of defect candidates is continued while the inspection sensitivity is reduced so as to decrease the number (for example, refer to Patent Document 1). However, with such a technique, defect extraction with a huge number of defects is eventually given up.

JP, 2011-022100, A

Therefore, according to one embodiment of the present invention, an inspection device and a method which can reduce an increase in inspection time even when the data amount of a defective portion is large is provided.

A pattern inspection apparatus according to one aspect of the present invention is
An optical image acquisition mechanism for acquiring optical images of a plurality of regions from a substrate on which a plurality of graphic patterns are formed,
Using a plurality of reference images corresponding to the optical image of the plurality of areas, a plurality of comparison units for performing parallel processing between the corresponding optical image and the reference image between at least some areas of the plurality of areas,
As a result of the comparison, at least one defect information generation unit that receives the defect image data determined to be defective and generates defect information based on the transferred data,
A transfer unit that determines the transfer order and timing of the defect image data according to the generation processing status of the defect information;
It is characterized by having.

Further, it is preferable to temporarily stop the acquisition of the optical image when the data capacity of the defective image data waiting to be transferred exceeds the threshold value.

Further, it is preferable to temporarily stop the acquisition of the optical image when the data capacity of the defective image data waiting to be transferred in one of the plurality of comparison units exceeds the threshold value.

Alternatively, it is also preferable to temporarily stop the acquisition of the optical image when the data capacities of the defective image data waiting to be transferred in all the comparison units among the plurality of comparison units exceed the threshold value.

A pattern inspection method according to one aspect of the present invention is
A step of acquiring optical images of a plurality of regions from a substrate on which a plurality of graphic patterns are formed;
Using a plurality of reference images corresponding to the optical images of the plurality of regions, the step of performing parallel processing between the corresponding optical image and the reference image between at least some regions of the plurality of regions,
As a result of the comparison, a process of receiving the defect image data determined to be a defect and generating defect information based on the transferred data,
Determining the transfer order and timing of the defect image data according to the generation processing status of the defect information,
It is characterized by having.

According to one aspect of the present invention, it is possible to reduce an increase in inspection time even when the data amount of a defective portion is large.

FIG. 3 is a configuration diagram showing a configuration of a pattern inspection device in the first embodiment. FIG. 3 is a conceptual diagram for explaining an inspection area in the first embodiment. FIG. 6 is a flowchart diagram showing main steps of the inspection method according to the first embodiment. FIG. 6 is a diagram for explaining a filter process in the first embodiment. 4 is a configuration diagram showing an example of an internal configuration of each comparison circuit in the first embodiment. FIG. 3 is a configuration diagram showing an example of an internal configuration of a transfer circuit in the first embodiment. FIG. 4 is a configuration diagram showing an example of an internal configuration of a coupling circuit in the first embodiment. FIG. FIG. 6 is a flowchart showing internal steps of a data transfer processing step in the first embodiment. FIG. 6 is a diagram for explaining an example of defect data in the first embodiment.

Embodiment 1.
FIG. 1 is a configuration diagram showing the configuration of the pattern inspection apparatus according to the first embodiment. In FIG. 1, an inspection apparatus 100 that inspects a substrate to be inspected, for example, a defect of a pattern formed on a mask includes an optical image acquisition mechanism 150 and a control system circuit 160.

The optical image acquisition mechanism 150 includes a light source 103, an illumination optical system 170, a movable XYθ table 102, a magnifying optical system 104, a photodiode array 105 (an example of a sensor), a sensor circuit 106, a stripe pattern memory 123, and a laser. It has a length measurement system 122 and an autoloader 130. On the XYθ table 102, the substrate 101 transferred from the autoloader 130 is arranged. The substrate 101 includes, for example, a photomask for exposure that transfers a pattern onto a semiconductor substrate such as a wafer. A plurality of patterns to be inspected are formed on this photomask. The substrate 101 is arranged on the XYθ table 102 with the pattern formation surface facing downward, for example.

In the control system circuit 160, a control computer 110 that controls the entire inspection apparatus 100, via a bus 120, a position circuit 107, a plurality of comparison circuits 108 (108a to 108c), a reference image creation circuit 112, an autoloader control circuit 113, The table control circuit 114, the coupling circuit 140, the transfer circuit 142, the magnetic disk device 109, the magnetic tape device 115, the flexible disk device (FD) 116, the CRT 117, the pattern monitor 118, and the printer 119 are connected. Further, the sensor circuit 106 is connected to the stripe pattern memory 123, and the stripe pattern memory 123 is connected to the plurality of comparison circuits 108a to 108c. The XYθ table 102 is driven by an X-axis motor, a Y-axis motor, and a θ-axis motor. The XYθ table 102 is an example of a stage.

A series of “˜circuits” such as the position circuit 107, the plurality of comparison circuits 108 (108a to 108c), the reference image creation circuit 112, the autoloader control circuit 113, the table control circuit 114, the combination circuit 140, and the transfer circuit 142 are It has a processing circuit. Such a processing circuit includes an electric circuit, a computer, a processor, a circuit board, a quantum circuit, a semiconductor device, or the like. Further, a common processing circuit (the same processing circuit) may be used for each "-circuit" except for the coupling circuit 140 which is the receiver of the data transfer. Alternatively, different processing circuits (separate processing circuits) may be used. For example, a series of “˜circuits” such as the position circuit 107, the plurality of comparison circuits 108 (108a to 108c), the reference image creation circuit 112, the autoloader control circuit 113, the table control circuit 114, and the transfer circuit 142 are controlled by the control computer 110. It may be configured and implemented. The program that causes the processor or the like to be executed may be recorded in a recording medium such as the magnetic disk device 109, the magnetic tape device 115, the FD 116, or a ROM (Read Only Memory).

In the inspection apparatus 100, the light source 103, the XYθ table 102, the illumination optical system 170, the magnifying optical system 104, the photodiode array 105, and the sensor circuit 106 constitute a high-magnification inspection optical system. The XYθ table 102 is driven by the table control circuit 114 under the control of the control computer 110. It is movable by a drive system such as a three-axis (X-Y-θ) motor that drives in the X direction, the Y direction, and the θ direction. As the X motor, Y motor, and θ motor, for example, step motors can be used. The XYθ table 102 can be moved in the horizontal and rotational directions by the motors for the XYθ axes. Then, the moving position of the substrate 101 placed on the XYθ table 102 is measured by the laser length measurement system 122 and supplied to the position circuit 107. The transfer of the substrate 101 from the autoloader 130 to the XYθ table 102 and the transfer processing of the substrate 101 from the XYθ table 102 to the autoloader 130 are controlled by the autoloader control circuit 113.

Drawing data (design data) that is the basis of pattern formation on the substrate 101 to be inspected is input from the outside of the inspection device 100 and stored in the magnetic disk device 109. A plurality of graphic patterns are defined in the drawing data, and each graphic pattern is usually composed of a combination of a plurality of element graphics. It should be noted that there may be a graphic pattern composed of one graphic. On the substrate 101 to be inspected, corresponding patterns are formed based on the respective graphic patterns defined by the drawing data.

Here, in FIG. 1, components necessary for explaining the first embodiment are described. It goes without saying that the inspection apparatus 100 may normally include other necessary configurations.

FIG. 2 is a conceptual diagram for explaining the inspection area in the first embodiment. As shown in FIG. 2, the inspection region 10 (entire inspection region) of the substrate 101 is virtually divided into a plurality of strip-shaped inspection stripes 20 having a scan width W in the Y direction, for example. Then, the inspection apparatus 100 acquires images (stripe area images) for each inspection stripe 20. With respect to each of the inspection stripes 20, a laser beam is used to capture an image of a graphic pattern arranged in the stripe region in the longitudinal direction (X direction) of the stripe region. In addition, in order to prevent missing of images, the plurality of inspection stripes 20 are set so that adjacent inspection stripes 20 overlap each other with a predetermined margin width, as described later.

An optical image is acquired while the photodiode array 105 is relatively continuously moved in the X direction by the movement of the XYθ table 102. The photodiode array 105 continuously captures an optical image having a scan width W as shown in FIG. In other words, the photodiode array 105, which is an example of the sensor, captures an optical image of the graphic pattern formed on the substrate 101 using the inspection light while moving relative to the XYθ table 102 (stage). In the first embodiment, after capturing an optical image of one inspection stripe 20, the optical image of the scan width W is similarly moved while moving to the position of the next inspection stripe 20 in the Y direction and moving in the opposite direction. Take images continuously. That is, the imaging is repeated in the forward (FWD)-back forward (BWD) direction in which the forward and backward passes in opposite directions.

Further, in the actual inspection, the stripe region image of each inspection stripe 20 is divided into a plurality of rectangular frame images 30 each having a size half the scan width, as shown in FIG. Then, the inspection is performed for each frame image 30. An area obtained by dividing the stripe area of each inspection stripe 20 into the size of the frame image 30 becomes a frame area. In other words, the stripe area of each inspection stripe 20 is divided into a plurality of rectangular frame areas each having a size half the scan width, as shown in FIG. For example, it is divided into a size of 512×512 pixels. Therefore, the reference image to be compared with the frame image 30 is similarly created for each frame area. The plurality of frame images 30 are set so that the adjacent frame images 30 overlap each other with a predetermined margin width, as described later.

Here, the imaging direction is not limited to the repetition of forward (FWD)-back forward (BWD). You may image from one direction. For example, FWD-FWD may be repeated. Alternatively, BWD-BWD may be repeated.

FIG. 3 is a flowchart showing essential steps of the inspection method according to the first embodiment. In FIG. 3, the inspection method according to the first embodiment includes a stripe image acquisition step (S102), a reference image creation step (S110), a plurality of parallel inspection steps (S120a to S120c), and a data transfer processing step (S130). ) And a joining process (S140). Each inspection process (S120a to S120c) performs a series of processes called a frame image creation process (S122), a positioning process (S124), and a comparison process process (S126) as internal processes.

As the stripe image acquisition step (S102), the optical image acquisition mechanism 150 acquires a plurality of optical images from the substrate 101 on which a plurality of graphic patterns are formed. Specifically, it operates as follows. First, the XYθ table 102 is moved to a position where the first inspection stripe 20 can be imaged. The pattern formed on the substrate 101 is irradiated with laser light (for example, DUV light) having a wavelength in the ultraviolet region or less as inspection light from an appropriate light source 103 via the illumination optical system 170. The light transmitted through the substrate 101 forms an optical image on a photodiode array 105 (an example of a sensor) via a magnifying optical system 104 and enters the photodiode array 105.

The image of the pattern formed on the photodiode array 105 is photoelectrically converted by each light receiving element of the photodiode array 105, and further A/D (analog/digital) converted by the sensor circuit 106. Then, the pixel data of the inspection stripe 20 to be measured is stored in the stripe pattern memory 123. When capturing such pixel data (stripe area image), the dynamic range of the photodiode array 105 is, for example, the maximum gray level when the amount of illumination light is 60%. After that, the stripe region image is sent to any of the plurality of comparison circuits 108a to 108c together with the data indicating the position of the substrate 101 on the XYθ table 102 output from the position circuit 107. The measurement data (pixel data) is, for example, 8-bit unsigned data, and expresses the gradation of lightness (light amount) of each pixel. For example, the stripe image data of the first inspection stripe 20 is output to the comparison circuit 108a. The stripe image data of the second inspection stripe 20 is output to the comparison circuit 108b. The stripe image data of the third inspection stripe 20 is output to the comparison circuit 108c. The stripe image data of the fourth inspection stripe 20 is output to the comparison circuit 108a again. Thereafter, the stripe image data is sequentially output. Alternatively, the control computer 110 selects, as an output destination, the comparison circuits 108a to 108c in which data processing is more advanced (vacant or vacant first) according to the data processing status of the plurality of comparison circuits 108a to 108c. It is also suitable.

As the reference image creating step (S110), the reference image creating circuit 112 (reference image creating unit) creates a plurality of reference images corresponding to the stripe images (optical images) of the plurality of inspection stripes 20 (regions). In the first embodiment, as the reference image for each inspection stripe 20, a reference image is created for each frame area so as to correspond to the frame image 30. However, it is not limited to this. The reference image may be created for each inspection stripe 20. Specifically, it operates as follows. The reference image creation circuit 112 first reads drawing data (design pattern data) from the storage device 109 through the control computer 110, and converts each graphic pattern defined in the read design pattern data into binary or multivalued image data. Convert to.

The figure defined in the design pattern data is, for example, a rectangle or triangle as a basic figure. For example, coordinates (x, y) at the reference position of the figure, side lengths, and figure types such as rectangle and triangle are distinguished. Graphic data defining the shape, size, position, etc. of each pattern graphic is stored with information such as a graphic code serving as an identifier.

When the design pattern data, which is such graphic data, is input to the reference image creating circuit 112, it is expanded into data for each graphic, and the graphic code indicating the graphic shape of the graphic data, the graphic size, etc. are interpreted. Then, it is developed into binary or multivalued design pattern image data as a pattern to be arranged in a square having a grid of a predetermined quantization size as a unit, and is output. In other words, the design data is read, the occupation rate of the figure in the design pattern is calculated for each square formed by virtually dividing the frame area into squares each having a predetermined size as a unit, and n-bit occupation data ( Design image data) is output. For example, it is preferable to set one square as one pixel. Then, assuming that one pixel has a resolution of 1/2 ⁸ (=1/256), a small area of 1/256 is allocated only for the area of the graphic arranged in the pixel, and the occupation rate in the pixel is increased. Calculate Then, it is created as 8-bit occupation rate data. The squares (inspection pixels) may be matched with the pixels of the measurement data.

Next, the reference image creating circuit 112 performs a filtering process on the design image data of the design pattern, which is the image data of the figure, using a filter function.

FIG. 4 is a diagram for explaining the filter processing according to the first embodiment. Pixel data of an optical image picked up from the substrate 101 is in a state in which a filter acts due to the resolution characteristics of an optical system used for image pickup, in other words, in an analog state that continuously changes, and therefore, for example, as shown in FIG. In addition, the image intensity (grayscale value) is different from the developed image (design image) of digital values. Therefore, the reference image creation circuit 112 creates a reference image that is close to the optical image by performing image processing (filtering) on the developed image. This makes it possible to match design image data, which is image data on the design side where the image intensity (shading value) is a digital value, with the image generation characteristics of the measurement data (optical image). The image data of the created reference image is sent to any of the plurality of comparison circuits 108a to 108c. Specifically, it is output to the same comparison circuit 108a (or 108b or 108c) as the output destination of the stripe image data of the inspection stripe 20 including the area indicated by the reference image.

As the plurality of inspection steps (S120a to S120c) arranged in parallel, the plurality of comparison circuits 108a to 108c (comparison section) use the plurality of reference images corresponding to the stripe images (optical images) of the plurality of inspection stripes 20 (regions). Then, the comparison process of the corresponding optical image and the reference image is performed in parallel between at least some regions of the plurality of inspection stripes 20. For example, the comparison circuit 108a compares the stripe image data of the first inspection stripe 20, the comparison circuit 108b compares the stripe image data of the second inspection stripe 20, and the comparison circuit 108c generates the third comparison image data. The comparison processing of the stripe image data of the inspection stripe 20 is performed in parallel. The control computer 110 allocates the inspection of the stripe image of the next inspection stripe 20 to the comparison circuit 108a (or 108b or 108c) for which the inspection processing is completed, and outputs the stripe data of the allocated inspection stripe 20. ..

FIG. 5 is a configuration diagram showing an example of the internal configuration of each comparison circuit in the first embodiment. In FIG. 5, storage devices 70, 71, 72, 76 such as a magnetic disk device, a frame image creation unit 74, an alignment unit 78, and a comparison processing unit 79 are provided in each comparison circuit of the plurality of comparison circuits 108a to 108c. Are arranged. A series of “-units” such as the frame image creation unit 74, the alignment unit 78, and the comparison processing unit 79 has a processing circuit. Such a processing circuit includes an electric circuit, a computer, a processor, a circuit board, a quantum circuit, a semiconductor device, or the like. Moreover, a common processing circuit (the same processing circuit) may be used for each “-circuit”. Alternatively, different processing circuits (separate processing circuits) may be used. The input data necessary for the frame image creation unit 74, the alignment unit 78, and the comparison processing unit 79 or the calculated results are stored in a memory (not shown) each time.

The stripe data (optical image data) input to each comparison circuit 108a, 108b, 108c is stored in the storage device 70, respectively. The reference image data input to the comparison circuits 108a, 108b, 108c are stored in the storage device 72, respectively. Hereinafter, the processing content of one of the plurality of comparison circuits 108a to 108c will be described. The processing contents of the comparison circuits 108a, 108b, 108c may be the same.

In the frame image creating step (S122), the frame image creating unit 74 creates the frame image 30 for each frame area shown in FIG. 2 using the stripe data for each inspection stripe 20. For example, a frame image of 512×512 pixels is created. The plurality of frame images 30 are created such that adjacent frame images 30 overlap each other with a predetermined margin width. Through such processing, a plurality of frame images 30 (optical images) corresponding to a plurality of frame regions are acquired. The plurality of frame images 30 are stored in the storage device 76. By the above, one image (measured image) data to be compared for inspection is generated.

As the alignment step (S124), the alignment unit 78 reads the frame image 30 (optical image) to be compared from the storage device 76, and similarly reads the reference image to be compared from the storage device 72. Then, the alignment is performed by a predetermined algorithm. For example, the least squares method is used for alignment.

As the comparison processing step (S126), the comparison processing unit 79 (comparison unit) compares the optical image and the reference image for each frame region (inspection unit region) 30. In other words, the comparison processing unit 79 compares, for each frame area of the plurality of frame areas (small areas), the frame image 30 (optical image) of the frame area and the reference image corresponding to the frame image 30 for each pixel. Then, the pattern defect is inspected. The comparison processing unit 79 compares the two for each pixel according to a predetermined determination condition, and determines the presence or absence of a defect such as a shape defect. As a determination condition, for example, both are compared for each pixel according to a predetermined algorithm to determine the presence or absence of a defect. For example, a difference value obtained by subtracting the pixel value of the frame image 30 from the pixel value of the reference image is calculated for each pixel, and when the difference value is larger than the threshold Th, it is determined as a defect. Then, the comparison result is output to the storage device 71. Here, as a result of the comparison, the data of the frame image 30 including the defective portion determined to be defective is temporarily stored in the storage device 71 as defective image data. Further, for example, coordinate data (defect specifying data) of the defect position is temporarily stored in the storage device 71. If there are a plurality of defects, the data of the frame image 30 including the defect portion is temporarily stored in the storage device 71 as defect image data for each defect. Similarly, for each defect, for example, coordinate data (defect specifying data) of the defect position is temporarily stored in the storage device 71. The defect image data and the defect identification data will be overwritten on the data of the next inspection stripe 20 after the transfer.

In addition, in the above-mentioned example, the case where the die-database inspection is performed is shown, but the case where the die-die inspection is performed may be performed. In such a case, another frame image 30 (die 2) in which the same pattern as the frame image 30 (die 1) to be inspected is arranged may be used as a reference image.

Here, as described above, when the defect is detected, the defect image data including the defect and the coordinate data for specifying the defect position are combined to generate the defect information which can be visually recognized by the user. Therefore, it is necessary to transfer each defect image data and each defect identification data to the combining circuit 140. However, when the number of defects, for example, about 1 million, which has increased enormously compared with the conventional number of defects of about 10,000, is detected, the time required for the transfer and combination processing increases. For example, if each defect image data or the like is simply transferred as it is in the order of inspection processing, the transfer speed cannot catch up and data waiting for transfer is accumulated. In addition, a memory swap operation or the like occurs in the processing after the transfer. In that case, the transfer and joining processes are stopped for a long time, and as a result, the inspection time may be significantly increased. Therefore, in the first embodiment, the data is not blindly transferred and the data waiting to be transferred is not increased. Specifically, it operates as follows.

FIG. 6 is a configuration diagram showing an example of the internal configuration of the transfer circuit according to the first embodiment. 6, in the transfer circuit 142, a total capacity calculation unit 42, an order/timing determination unit 43, a transfer processing unit 44, a determination unit 45, a pause processing unit 46, a restart processing unit 47, and a determination unit 48 are arranged. Has been done. A series of “-units” such as the total capacity calculation unit 42, the order/timing determination unit 43, the transfer processing unit 44, the determination unit 45, the pause processing unit 46, the restart processing unit 47, and the determination unit 48 has a processing circuit. .. Such a processing circuit includes an electric circuit, a computer, a processor, a circuit board, a quantum circuit, a semiconductor device, or the like. Moreover, a common processing circuit (the same processing circuit) may be used for each “-circuit”. Alternatively, different processing circuits (separate processing circuits) may be used. The input data necessary for the total capacity calculation unit 42, the order/timing determination unit 43, the transfer processing unit 44, the determination unit 45, the temporary stop processing unit 46, the restart processing unit 47, and the determination unit 48, or the operation result are calculated each time. It is stored in a memory (not shown).

FIG. 7 is a configuration diagram showing an example of the internal configuration of the coupling circuit in the first embodiment. 7, in the coupling circuit 140, storage devices 50 and 56 such as a magnetic disk device, a defect determination section 52, and a coupling processing section 54 are arranged. A series of “-units” such as the defect determination unit 52 and the combination processing unit 54 has a processing circuit. Such a processing circuit includes an electric circuit, a computer, a processor, a circuit board, a quantum circuit, a semiconductor device, or the like. Moreover, a common processing circuit (the same processing circuit) may be used for each “-circuit”. Alternatively, different processing circuits (separate processing circuits) may be used. The input data necessary for the defect determination unit 52 and the combination processing unit 54 or the calculated results are stored in a memory (not shown) each time.

In the data transfer processing step (S130), the transfer circuit 142 causes the defect image data for each defect temporarily stored in the storage device 71 of each of the comparison circuits 108a, 108b, 108c and the coordinate data for each defect (defect identification). Data) and are transferred to the combining circuit 140. The transfer circuit 142 (transfer unit) determines the transfer order and timing of the defect image data according to the defect information generation processing status in the combining circuit 140. Specifically, it operates as follows.

FIG. 8 is a flowchart showing internal steps of the data transfer processing step in the first embodiment. In FIG. 8, the data transfer processing step (S130) includes, as internal steps, a defective data total capacity calculation step (S132) for each stripe, a transfer order/timing determination step (S134), and a transfer processing step (S135). A series of steps of a determination step (S136), a temporary stop processing step (S137), a scan restart processing step (S138), and a determination step (S139) are performed.

In the defect data total capacity calculation step (S132) for each stripe, the total capacity calculation unit 42, for each inspection stripe 20, the defect image data of all the defects generated in the target inspection stripe 20 and the defect identification data of the defect. Then, the total defect data capacity of all the defects generated in the target inspection stripe 20 is calculated by summing the data capacities of.

FIG. 9 is a diagram for explaining an example of the defect data according to the first embodiment. In FIG. 9, the inspection stripes 20a, 20b, 20c are set to overlap each other with a predetermined margin width. Further, the frame areas in the inspection stripes 20a, 20b, 20c are also set so that the frame areas overlap each other with a predetermined margin width. In the example of FIG. 9, for example, the comparison circuit 108a inspects the stripe data of the inspection stripe 20a (comparison processing), and the comparison circuit 108b inspects the stripe data of the inspection stripe 20b (comparison processing). For example, it is assumed that the comparison circuit 108c inspects (comparison processing) the stripe data of the inspection stripe 20c. In the example of FIG. 9, in the inspection stripe 20a, for example, the case where the defect A occurs at the position of the margin area where the four frame images 30a, 30b, 30c, and 30d overlap each other is shown. In this case, as the defect image data of the defect A, each data of the four frame images 30a, 30b, 30c, 30d is to be transferred. Further, the coordinate data of the defect A is to be transferred for each of the four frame images 30a, 30b, 30c, and 30d. On the other hand, in the example of FIG. 9, in the inspection stripe 20b, for example, a case where a defect B occurs at a position in one frame image 30a where a plurality of frame regions do not overlap each other is shown. In such a case, as the defect image data of the defect B, the data of one frame image 30a is the transfer target. Further, the coordinate data of the defect B in one frame image 30a is the transfer target. Similarly, in the inspection stripe 20c, for example, a case where a defect C occurs at a position within one frame image 30b where a plurality of frame regions do not overlap each other is shown. In such a case, the data of one frame image 30b is the transfer target as the defect image data of the defect C. Further, the coordinate data of the defect C in one frame image 30b is the transfer target. In this case, the total defective data capacity of the inspection stripe 20a is as large as 1200 MB, whereas the total defective data capacity of the inspection stripes 20b and 20c is 300 MB, which is smaller than that of the inspection stripe 20a. Become. In this way, the amount of data required for transfer per defect varies depending on the defect occurrence position. Furthermore, if a plurality of defects occur in one inspection stripe 20, the data amount will increase accordingly.

As the transfer order/timing determining step (S134), the order/timing determining unit 43 determines the transfer order and timing of the defect image data according to the generation status of the defect information in the combining circuit 140. Specifically, it operates as follows. In order to smoothly execute the transfer of the defect transfer data including the defect image data, it is necessary to select a period in which the transfer process is not performed between any of the comparison circuits 108a, 108b, 108c and the coupling circuit 140. There is. When transfer processing is being performed between any of the comparison circuits 108a, 108b, 108c and the coupling circuit 140, the transfer of defective transfer data from the other comparison circuit 108 is delayed. Therefore, it is necessary to determine the transfer timing as a period during which the defect transfer data is not transferred. In order to smoothly execute the transfer of the defect transfer data, at the timing of the transfer, the free space of the storage capacity that can be stored in the storage device 50 in the transfer destination coupling circuit 140 is the inspection stripe 20 to be transferred. It must be greater than or equal to the total defective data capacity. Therefore, at the timing of the transfer of the defect transfer data, the generation status of the defect information in the combining circuit 140 in the previously transferred defect transfer data of the inspection stripe 20 has not progressed, and the storage device 50 becomes empty. If the capacity is not secured, the transfer will be stagnant. Therefore, when the defect information generation processing status is not advanced and the free space of the storage device 50 for the inspection stripe 20 for which the comparison processing has been completed is not secured, the inspection stripe 20 for which the comparison processing has been completed is Also, the transfer order of the defective image data of the inspection stripe 20 that can secure the free space of the storage device 50 is first. For example, in the example of FIG. 9, when the free capacity of the storage device 50 is 600 MB or more and less than 1200 MB, even if the comparison processing of the inspection stripe 20a in the comparison circuit 108a is completed first, the inspection stripe 20b or the inspection is executed. The transfer order and timing are determined so as to give priority to the transfer of the defective transfer data of the stripe 20c or both of the inspection stripes 20b and 20c.

In the transfer processing step (S135), the transfer processing unit 44 combines the defect transfer data of the target inspection stripe 20 with the combining circuit 140 according to the transfer order and timing of the defect transfer data including the determined defect image data. Transfer to. As a result, the storage capacity of the storage device 71 of any of the comparison circuits 108a, 108b, and 108c can be freed without causing a stagnation of transfer.

As described above, the defective transfer data of the inspection stripe 20 having the total data capacity that can be transferred without causing the transfer stagnation is preferentially transferred to the coupling circuit 140. However, as a result of such processing, the comparison circuit whose transfer order has been moved backward (for example, the comparison circuit 108a) sequentially stores the comparison processing results of the next inspection stripe 20, so the free capacity of the storage device 71 decreases. To go. When the free capacity of the storage device 71 is insufficient, the comparison process (inspection) in the comparison circuit (for example, the comparison circuit 108a) will be delayed this time. Therefore, the first embodiment operates as follows.

In the determination step (S136), the determination unit 45 determines whether or not the data capacities of the defective image data waiting for transfer stored in the storage device 71 of each of the comparison circuits 108a, 108b, and 108c have exceeded the respective thresholds.

In the suspension processing step (S137), the suspension processing unit 46 performs control when the data capacity of defective image data waiting for transfer in one of the plurality of comparison circuits 108a, 108b, and 108c exceeds the threshold Th. The image acquisition mechanism 150 is caused to temporarily stop scanning via the computer 110. In such a case, the image acquisition mechanism 150 suspends the acquisition of the optical image. Then, while the scan is temporarily stopped, the processing in the combining circuit 140 is advanced, and the process of transferring the defective image data waiting to be transferred to the combining circuit 140 is sequentially advanced. It is possible to reduce the inspection time as a result by controlling the scan operation to be temporarily stopped to secure the storage capacity of the storage device, rather than the processing in each circuit being stagnant.

Alternatively, when the data capacities of the defective image data waiting to be transferred in all the comparison circuits 108a, 108b, 108c among the plurality of comparison circuits 108a, 108b, 108c both exceed the threshold value, the acquisition of the optical image is temporarily stopped. It is also preferable to have such a configuration. If there is a comparison circuit 108 that does not exceed the threshold, the comparison circuit 108 can continue processing.

As the scan restart processing step (S138), the restart processing unit 47 waits for transfer in one of the plurality of comparison circuits 108a, 108b, 108c (or all of the plurality of comparison circuits 108a, 108b, 108c). When the data capacity of the defective image data decreases below the threshold value Th, the image acquisition mechanism 150 is caused to restart the scanning operation via the control computer 110. In such a case, the image acquisition mechanism 150 restarts the acquisition of the optical image. In the determination step (S136), the scan restart processing step (S138) may be omitted until it is first determined that the data capacity of the defective image data waiting to be transferred exceeds the threshold value.

As the determination step (S139), the determination unit 48 determines whether or not the transfer processing of the defective transfer data of all the inspection stripes 20 is completed. The data transfer processing step (S130) ends when the transfer processing of the defective transfer data of all the inspection stripes 20 ends. If there is an inspection stripe 20 for which the transfer processing has not been completed, the process returns to the defective data total capacity calculation step (S132) for each stripe, and the internal step of the data transfer processing step (S130) is repeated.

In the combining step (S140), the combining circuit 140 (defect information generation unit) receives the transfer of the defect transfer data including the defect image data determined to be defective as a result of the comparison, and the defect information based on the transferred data. To generate. In the example of FIG. 1, one coupling circuit 140 is shown, but it is not limited to this. At least one coupling circuit 140 may be arranged. The defect transfer data transferred to the coupling circuit 140 is temporarily stored in the storage device 50.

The defect determining unit 52 reads coordinate data (defect specifying data) from the storage device 50 and determines overlapping defect image data based on the coordinate data. As described with reference to FIG. 9, a plurality of defect image data are transferred depending on the position of the defect. Therefore, the defect determination unit 52 determines and extracts these overlapping images. Note that, as shown in FIG. 9, since there is an overlapping area between the inspection stripes 20 as well, it goes without saying that the overlapping of the defect image data may occur between the inspection stripes 20.

Next, the combination processing unit 54 creates defect information in which one of a plurality of overlapping defect image data (frame images 30) and defect coordinates are combined for each defect. As the defect information, for example, an image in which the defect coordinates are superimposed on the defect coordinate position on the defect image data is generated. In addition, when a plurality of defects exist in the same defect image data, it is suitable to generate an image in which defect coordinates of a plurality of defects are superimposed on one defect image data (frame image 30). The created defect information is stored in the storage device 56 and is also output to the magnetic disk device 109, the magnetic tape device 115, the flexible disk device (FD) 116, the CRT 117, the pattern monitor 118, or the printer 119. Just do it. The defect transfer data including the defect image data for which the defect information is created is deleted from the storage device 50. Alternatively, it is regarded as free space and then overwritten with the next data.

As described above, according to the first embodiment, it is possible to reduce the increase in inspection time even when the data amount of the defective portion is large.

The embodiments have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. For example, in the embodiment, the transmissive illumination optical system using transmitted light is shown as the illumination optical system 170, but the present invention is not limited to this. For example, a reflection illumination optical system using reflected light may be used. Alternatively, the transmitted light and the reflected light may be simultaneously used by combining the transmitted light optical system and the reflected light optical system.
The light source 103 is not limited to the ultraviolet (light) light source, and may be an electron beam emission source.

Moreover, although the description of the parts such as the device configuration and the control method that are not directly necessary for the description of the present invention is omitted, the required device configuration and the control method can be appropriately selected and used. For example, although the description of the control unit configuration for controlling the inspection apparatus 100 is omitted, it goes without saying that a required control unit configuration is appropriately selected and used.

In addition, all pattern inspection apparatuses and pattern inspection methods that have the elements of the present invention and can be appropriately modified in design by those skilled in the art are included in the scope of the present invention.

10 inspection region 20 inspection stripe 30 frame image 42 total capacity calculation unit 43 order/timing determination unit 44 transfer processing unit 45 determination unit 46 pause processing unit 47 restart processing unit 48 determination unit 50, 56 storage device 52 defect determination unit 54 combination Processing units 70, 71, 72, 76 Storage device 74 Frame image generation unit 78 Positioning unit 79 Comparison processing unit 100 Inspection device 101 Substrate 102 XYθ table 103 Light source 104 Enlarging optical system 105 Photodiode array 106 Sensor circuit 107 Position circuit 108 Comparison Circuit 109 Magnetic disk device 110 Control computer 112 Reference image creation circuit 113 Autoloader control circuit 114 Table control circuit 115 Magnetic tape device 116 FD
117 CRT
118 pattern monitor 119 printer 120 bus 122 laser measuring system 123 stripe pattern memory 130 autoloader 140 coupling circuit 142 transfer circuit 150 optical image acquisition mechanism 160 control system circuit 170 illumination optical system

Claims (6)

An optical image acquisition mechanism for acquiring optical images of a plurality of regions from a substrate on which a plurality of graphic patterns are formed,
Using a plurality of reference images corresponding to the optical images of the plurality of regions, a plurality of comparison units for performing parallel processing of the corresponding optical image and the reference image between at least some regions of the plurality of regions, ,
As a result of the comparison, at least one defect information generation unit that receives the defect image data determined to be defective and generates defect information based on the transferred data,
A transfer unit that determines the transfer order and timing of the defect image data according to the generation processing status of the defect information;
A pattern inspection device comprising: The pattern inspection apparatus according to claim 1, wherein the acquisition of the optical image is temporarily stopped when the data capacity of the defect image data waiting to be transferred exceeds a threshold value. The pattern inspection according to claim 1, wherein the acquisition of the optical image is temporarily stopped when the data capacity of the defective image data waiting to be transferred in one of the plurality of comparison units exceeds a threshold value. apparatus. The acquisition of the optical image is temporarily stopped when the data capacities of the defective image data waiting to be transferred in all the comparison units of the plurality of comparison units exceed a threshold value. Pattern inspection device. The defect information generation unit has a storage device,
If the generation processing status of the defect information is not advanced and the free space of the storage device for the area where the comparison processing has been completed is not secured, even if the comparison processing is completed afterwards, 5. The pattern inspection apparatus according to claim 1, wherein a transfer order of the defective image data in an area where the free space of the storage device can be secured is set first. A step of acquiring optical images of a plurality of regions from a substrate on which a plurality of graphic patterns are formed;
Using a plurality of reference images corresponding to the optical images of the plurality of regions, a step of performing parallel processing between the corresponding optical image and the reference image between at least some regions of the plurality of regions,
As a result of the comparison, a process of receiving the defect image data determined to be a defect and generating defect information based on the transferred data,
Determining a transfer order and timing of the defect image data according to a generation processing state of the defect information,
A pattern inspection method comprising:

Images