JP2011064472A - Pattern inspection system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inspection system for performing maintenance of a laser light source without hindering operation of inspection processing to the utmost. <P>SOLUTION: This pattern inspection system 100 includes: a laser light source device 103; an optical image acquisition device 150 for applying laser light, and acquiring an optical image of a pattern of an inspection sample; a comparison device 140 for inputting the optical image, and comparing the optical image with a comparison object image; and a control device 160 for controlling the laser light source device and the optical image acquisition device. The control device 160 inputs periodically an identifier showing the degree of necessity of maintenance operation of the laser light source device 103 from the laser light source device and an elapsed time from execution of previous maintenance operation, and outputs a maintenance operation execution command to the laser light source device based on at least either of the identifier and the elapsed time. The laser light source device 103 executes maintenance operation of the laser light source device 103 based on the maintenance operation execution command. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a pattern inspection system, for example, a pattern inspection technique for inspecting a pattern defect of an object to be a sample used in semiconductor manufacturing, a photomask used when manufacturing a semiconductor element or a liquid crystal display (LCD), The present invention relates to a system for inspecting a defect of an extremely small pattern such as a wafer or a liquid crystal substrate, and a maintenance execution method for the light source.

  In recent years, the circuit line width required for a semiconductor element has been increasingly narrowed as a large scale integrated circuit (LSI) is highly integrated and has a large capacity. These semiconductor elements use an original pattern pattern (also referred to as a mask or a reticle, hereinafter referred to as a mask) on which a circuit pattern is formed, and the pattern is exposed and transferred onto a wafer by a reduction projection exposure apparatus called a stepper. It is manufactured by forming a circuit. Therefore, a pattern drawing apparatus capable of drawing a fine circuit pattern is used for manufacturing a mask for transferring such a fine circuit pattern onto a wafer. A pattern circuit may be directly drawn on a wafer using such a pattern drawing apparatus. For example, drawing is performed using an electron beam or a laser beam.

  In addition, improvement in yield is indispensable for manufacturing an LSI that requires a large amount of manufacturing cost. However, as represented by a 1 gigabit class DRAM (Random Access Memory), the pattern constituting the LSI is about to be in the order of submicron to nanometer. One of the major factors that reduce the yield is a pattern defect of a mask used when an ultrafine pattern is exposed and transferred onto a semiconductor wafer by a photolithography technique. In recent years, with the miniaturization of LSI pattern dimensions formed on semiconductor wafers, the dimensions that must be detected as pattern defects have become extremely small. Therefore, it is necessary to improve the accuracy of a pattern inspection apparatus that inspects defects in a transfer mask used in LSI manufacturing.

  On the other hand, with the development of multimedia, LCDs (Liquid Crystal Display) are increasing in size of the liquid crystal substrate to 500 mm × 600 mm or more, and TFTs (Thin Film Transistors) formed on the liquid crystal substrate. : Thin film transistors) and the like are being miniaturized. 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.

  Here, in a conventional pattern inspection apparatus, an optical image obtained by imaging a pattern formed on a sample such as a lithography mask using a magnifying optical system at a predetermined magnification and an identical pattern on the sample are captured. It is known to perform an inspection by comparing with an optical image. For example, as a pattern inspection method, a “die to die inspection” method in which optical image data obtained by imaging the same pattern at different locations on the same mask is compared, or a CAD used for drawing a mask pattern Image data (reference image data) that is used as a reference for comparison is generated based on drawing data (design data) obtained by converting the data into the inspection device input format, and this is compared with optical image data that is used as measurement data obtained by imaging the pattern. There is a “die to database inspection” method. In the inspection method in such an inspection apparatus, the sample is placed on the stage, and the stage is moved so that the light beam scans on the sample and the inspection is performed. The sample is irradiated with a light beam by a light source and an illumination optical system. The light transmitted or reflected by the sample is imaged on the sensor via the optical system. The image picked up by the sensor is sent to the comparison circuit as optical image (measurement image) data. In the comparison circuit, the reference image data and the optical image data are compared according to an appropriate algorithm after the images are aligned, and if they do not match, it is determined that there is a pattern defect.

  Here, the laser light source of the inspection apparatus requires maintenance (maintenance) in order to maintain the light quantity. When an excimer laser, for example, is used as the laser beam, periodic self-maintenance such as gas replacement is required for self-maintenance. The working time is only a few minutes at the maximum, and this self-maintenance can be performed during the replacement operation of the substrate to be inspected or during the initialization of the inspection apparatus. However, with the recent miniaturization of patterns, a light source that generates a higher quality laser than a discharge laser such as an excimer laser is required as a laser light source. In order to provide such higher-quality light, a laser light source that requires many optical components is required, and self-maintenance of the laser light source has become more time consuming. Therefore, it is not in time for the conventional substrate replacement operation or during the initialization of the apparatus. Therefore, time for maintenance is required. Therefore, if the maintenance operation is always performed when the maintenance operation is immediately required on the laser light source side or when the laser light source is stopped, the operation of the inspection process may be hindered. Therefore, it is necessary to devise maintenance of the laser light source without interfering with the operation of the inspection process as much as possible. However, conventionally, there has not been a sufficient mechanism for dealing with such a problem.

  Although not an inspection apparatus, a technique is disclosed in which an exposure apparatus using a laser light source is controlled as follows for a plurality of systems in which a laser apparatus and an exposure apparatus are combined into one system. Specifically, when one of the laser devices stops due to failure or maintenance, the exposure management controller controls the drive mirror of the distributor in synchronization with the operating status of the plurality of exposure devices, and the remaining lasers The laser beam from the apparatus is supplied to an exposure apparatus that is paired with a laser apparatus that is stopped. The exposure management controller performs the above-described control at a timing when a certain exposure apparatus temporarily does not need to supply laser light due to lot exchange or the like (see, for example, Patent Document 1). However, such laser device switching control does not control the failure or maintenance of the laser light source itself that requires failure or maintenance, and does not have a laser light source maintenance mechanism.

JP 2006-278916 A

  As described above, the laser light source of the inspection apparatus requires maintenance (maintenance) in order to maintain the light quantity. However, since it does not end in about a few minutes as in the past, there has been a sufficient mechanism in the past, despite the need for a mechanism to maintain the laser light source without interfering with the operation of the inspection process as much as possible. It wasn't.

  Accordingly, an object of the present invention is to provide an inspection system for overcoming the above-described problems and performing maintenance of a laser light source without interfering with the operation of inspection processing as much as possible.

The pattern inspection system according to one aspect of the present invention includes:
A laser light source device for generating laser light;
An optical image acquisition device that illuminates the laser beam onto the inspection sample on which a pattern is formed, and acquires an optical image of the pattern;
A comparison device for inputting the optical image and comparing the optical image with a comparison target image;
A control device for controlling the laser light source device and the optical image acquisition device;
With
The laser light source device acquires an identifier indicating the degree of necessity of the maintenance operation of the laser light source device and an elapsed time since the previous maintenance operation,
The control device periodically inputs the identifier and the elapsed time from the laser light source device, and a trigger for the laser light source device to perform a maintenance operation based on at least one of the identifier and the elapsed time; A maintenance operation execution command is output to the laser light source device,
The laser light source device receives the maintenance operation execution command from the control device, and executes the maintenance operation of the laser light source device based on the maintenance operation execution command.

  According to the present invention, the maintenance operation timing of the laser light source device can be managed and controlled on the host device side of the laser light source device based on the degree of necessity of the maintenance operation and the elapsed time from the previous maintenance operation. Therefore, it is possible to maintain the laser light source without interfering with the operation of the inspection process as much as possible.

1 is a conceptual diagram showing a configuration of a pattern inspection system in a first embodiment. 3 is a conceptual diagram illustrating an example of an internal configuration of an optical image acquisition device and a control device according to Embodiment 1. FIG. 2 is a conceptual diagram illustrating an example of an internal configuration of a laser light source device in Embodiment 1. FIG. 2 is a conceptual diagram illustrating an example of an internal configuration of a comparison device according to Embodiment 1. FIG. 2 is a conceptual diagram illustrating an example of an internal configuration of a host control computer apparatus according to Embodiment 1. FIG. 6 is a diagram for explaining an optical image acquisition procedure according to Embodiment 1. FIG. 6 is a diagram for describing filter processing according to Embodiment 1. FIG. FIG. 3 is a flowchart showing main steps of a maintenance level storing method in the laser light source device in the first embodiment. FIG. 4 is a flowchart showing main steps of an automatic maintenance operation start determination method in the laser light source device in the first embodiment. FIG. 6 is a flowchart showing main steps of a maintenance operation execution command output determination method in the control device in the first embodiment. FIG. 3 is a flowchart showing main steps of a command processing method in the control device in the first embodiment. FIG. 6 is a flowchart showing the steps of an inspection program in the host control computer in the first embodiment. It is a flowchart figure which shows the principal part process of the maintenance operation execution instruction command output judgment method in the host control computer performed in parallel with the inspection process execution process of FIG. FIG. 3 is a flowchart showing main steps of the maintenance necessity determination method according to the first embodiment. 6 is a diagram showing an example of an execution schedule of automatic maintenance operation in the time designation mode in Embodiment 1. FIG. FIG. 10 is a diagram showing another example of an execution schedule for automatic maintenance operation in the time designation mode in the first embodiment. FIG. 10 is a diagram showing another example of an execution schedule for automatic maintenance operation in the time designation mode in the first embodiment. 6 is a diagram showing an example of an execution schedule of automatic maintenance operation in the interval designation mode in Embodiment 1. FIG. 6 is a diagram illustrating an example of an execution schedule of an automatic maintenance operation in a combination of a time specification mode and an interval specification mode in Embodiment 1. FIG. 6 is a diagram illustrating an example of an execution schedule of an automatic maintenance operation in a combination of a time specification mode and a flag specification mode in Embodiment 1. FIG. 6 is a diagram illustrating an example of an execution schedule of an automatic maintenance operation in a combination of a time designation mode with a week / month unit designation mode and a flag designation mode according to Embodiment 1. FIG. It is a conceptual diagram which shows the other structure of the pattern inspection system in Embodiment 1. It is a figure for demonstrating another optical image acquisition method.

Embodiment 1 FIG.
FIG. 1 is a conceptual diagram showing the configuration of the pattern inspection system in the first embodiment. In FIG. 1, a pattern inspection system 100 for inspecting a defect of a sample using a substrate such as a mask or wafer on which a pattern is formed includes a laser light source device 103, an optical image acquisition device 150, a comparison device 140, A control device 160 and a host control computer 200 are provided. The laser light source device 103 generates laser light toward the optical image acquisition device 150. The optical image acquisition device 150 illuminates a sample to be inspected with a pattern with a laser beam, and receives the transmitted light transmitted through the inspection surface of the sample or the reflected light reflected by the inspection surface, thereby obtaining an optical image of the pattern. get. The optical image of the pattern is output to the comparison device 140 together with the position data (coordinate data) of the image, and the optical image is compared with the comparison target image in the comparison device 140. The control device 160 controls the laser light source device 103 and the optical image acquisition device 150. The host control computer 200 controls the entire inspection process by controlling the control device 160 and the comparison device 140. Each device is connected by a control cable or the like.

  FIG. 2 is a conceptual diagram illustrating an example of an internal configuration of the optical image acquisition device and the control device according to the first embodiment. In FIG. 2, the optical image acquisition device 150 includes an XYθ table 102, an enlargement optical system 104, a photodiode array 105, a sensor circuit 106, a laser length measurement system 122, an autoloader 130, an illumination optical system 170, and a stripe pattern memory 146. ing. The XYθ table 102 is driven by an X-axis motor, a Y-axis motor, and a θ-axis motor.

  In the control device 160, a CPU 110 serving as a computer transmits an autoloader control circuit 113, a table control circuit 114, a magnetic disk device 109 as an example of a storage device, a magnetic tape device 115, a flexible disk via a bus 120 serving as a data transmission path. A device (FD) 116, a CRT 117, a pattern monitor 118, a printer 119, an external interface (I / F) circuit 121, and a memory 123 as an example of a storage device are connected. The table control circuit 114 controls the position of the XYθ table 102 by drivingly controlling the X-axis motor, the Y-axis motor, and the θ-axis motor in the optical image acquisition device 150. The autoloader control circuit 113 controls the autoloader 130 in the optical image acquisition device 150. Information input to the CPU 110 or information being calculated is stored in the memory 123 each time. Control signals to the laser light source device 103 and the optical image acquisition device 150 are output via the I / F circuit 121, and information from the laser light source device 103 and the optical image acquisition device 150 are output via the I / F circuit 121. Entered.

  In FIG. 2, components necessary for explaining the first embodiment are described. Needless to say, the optical image acquisition device 150 and the control device 160 may normally include other necessary configurations.

  FIG. 3 is a conceptual diagram illustrating an example of an internal configuration of the laser light source device according to the first embodiment. In FIG. 3, the laser light source device 103 includes a CPU 171 serving as a computer, a memory 172, an external I / F 174, a storage device 175, a control circuit 176, and a laser light source 178. The control circuit 176 controls the laser light source 178 in accordance with an instruction from the CPU 171. Laser light used for inspection is output from the laser light source 178. The CPU 171, the memory 172, the external I / F 174, the storage device 175, and the control circuit 176 are connected to each other via a bus (not shown). Information input to the CPU 171 or information being calculated is stored in the memory 172 each time. A control signal from the control device 160 is input via the I / F 174, and information to the control device 160 is output via the I / F 174.

  FIG. 4 is a conceptual diagram illustrating an example of an internal configuration of the comparison device according to the first embodiment. In FIG. 4, in the comparison device 140, a CPU 141 serving as a computer has a position circuit 107, a comparison circuit 108 serving as an example of a comparison unit, a development circuit 111, a reference image generation circuit 112, and the like via a bus 144 serving as a data transmission path. A magnetic disk device 142 as an example of a storage device, an external I / F circuit 143, a magnetic tape device 145, a flexible disk device (FD) 133, a CRT 147, a pattern monitor 148, a printer 149, and a memory 132 as an example of a storage device. It is connected. Information input to the CPU 141 or information being calculated is stored in the memory 132 each time. A control signal from the host control computer 200 is input via the I / F circuit 143, and information to the host control computer 200 is output via the I / F circuit 143.

  FIG. 5 is a conceptual diagram showing an example of the internal configuration of the host control computer apparatus according to the first embodiment. In FIG. 5, a host control computer 200 includes a CPU 202 serving as a computer via a bus 218 serving as a data transmission path, a memory 204 serving as an example of a storage device, a magnetic disk device 206 serving as an example of a storage device, and an external I / O. F208, flexible disk device (FD) 210, CRT 212, pattern monitor 214, and printer 216 are connected. Information input to the CPU 202 or information being calculated is stored in the memory 204 each time. Control signals to the control device 160 and the comparison device 140 are output via the I / F 208, and information from the control device 160 and the comparison device 140 is input via the I / F 208.

  The sample is inspected as follows. Before starting the inspection, first, the photomask 101 to be inspected by the autoloader 130 controlled by the autoloader control circuit 113 is placed on the XYθ table 102 provided so as to be movable in the horizontal and rotational directions by the motors of the XYθ axes. And mounted on the XYθ table 102. The design pattern information (design data) used when forming the pattern of the photomask 101 is input to the comparison device 140 from the outside of the comparison device 140 and stored in the magnetic disk device 142 which is an example of a storage device (storage unit). Is done.

  The XYθ table 102 is driven by the table control circuit 114 under the control of the CPU 110. It can be moved by a drive system such as a three-axis (XY-θ) motor that drives in the X, Y, and θ directions. For example, step motors can be used as these X motor, Y motor, and θ motor. The movement position of the XYθ table 102 is measured by the laser length measurement system 122 and supplied to the position circuit 107. The photomask 101 on the XYθ table 102 is automatically conveyed from the autoloader 130 driven by the autoloader control circuit 113, and is automatically discharged after the inspection is completed.

  As an optical image acquisition step, the optical image acquisition device 150 acquires optical image data (measurement data) on the photomask 101 that is a patterned sample to be inspected. Specifically, the optical image data is acquired as follows. The pattern formed on the photomask 101 is irradiated with laser light output from the laser light source device 103 from above the XYθ table 102. The light beam emitted from the laser light source device 103 irradiates the photomask 101 via the illumination optical system 170. A magnifying optical system 104, a photodiode array 105, and a sensor circuit 106 are arranged below the photomask 101, and the light transmitted through the photomask 101 is optically imaged on the photodiode array 105 via the magnifying optical system 104. Is imaged and incident. The magnifying optical system 104 may be automatically focused by an unillustrated autofocus mechanism. Further, the reflected illumination optical system (not shown) may irradiate the photomask 101, and the reflected light may be formed as an optical image and incident on the photodiode array 105 via the magnifying optical system 104.

  FIG. 6 is a diagram for explaining an optical image acquisition procedure according to the first embodiment. As shown in FIG. 6, the inspection area is virtually divided into a plurality of strip-shaped inspection stripes 20 having a scan width W, for example, in the Y direction. Further, the operation of the XYθ table 102 is controlled so that the divided inspection stripes 20 are continuously scanned, and an optical image is acquired while moving in the X direction. In the photodiode array 105, images having a scan width W as shown in FIG. 6 are continuously input. Then, after acquiring the image of the first inspection stripe 20, the image of the scan width W is continuously input in the same manner while moving the image of the second inspection stripe 20 in the opposite direction. When an image in the third inspection stripe 20 is acquired, the image is moved in the direction opposite to the direction in which the image in the second inspection stripe 20 is acquired, that is, in the direction in which the image in the first inspection stripe 20 is acquired. While getting the image. In this way, it is possible to shorten a useless processing time by continuously acquiring images. Although the forward (FWD) -backward (BWD) method is used here, the present invention is not limited to this, and a forward (FWD) -forward (FWD) method may be used.

  The pattern image formed on the photodiode array 105 is photoelectrically converted by the photodiode array 105 and further A / D (analog-digital) converted by the sensor circuit 106. The photodiode array 105 is provided with a sensor such as a TDI (Time Delay Integrator) sensor. The TDI sensor images the pattern of the photomask 101 by continuously moving the XYθ table 102 serving as a stage in the X-axis direction. The laser light source device 103, the magnifying optical system 104, the photodiode array 105, and the sensor circuit 106 constitute a high-magnification inspection optical system.

  The measurement data (optical image data) of each inspection stripe 20 output from the sensor circuit 106 is temporarily stored in the stripe pattern memory 146 for each inspection stripe 20. The measurement data of each inspection stripe 20 is sequentially output to the comparison circuit 108 together with data indicating the position of the photomask 101 on the XYθ table 102 output from the position circuit 107. The measurement data is, for example, 8-bit unsigned data for each pixel, and the brightness gradation of each pixel is expressed by, for example, 0 to 255.

  As a development processing step, the development circuit 111 reads design data from the magnetic disk device 142 through the CPU 141 for each predetermined area, and outputs the read design data of the photomask 101 serving as a sample to be inspected to a binary or multi-value. Conversion (development processing) into developed image data which is image data. The predetermined region may be, for example, an image region (area) to be compared with the optical image. For example, an area (area) of 1024 × 1024 pixels is assumed. In the first embodiment, a case where the pixel size of the optical image and the pixel size of the developed image are the same size will be described as an example. However, the present invention is not limited to this, and as will be described later, the pixel size of the optical image and the pixel size of the developed image may be different. The development circuit 111 is an example of a development image generation unit.

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

When such graphic data is input to the expansion circuit 111, it expands to data for each graphic, and interprets graphic codes, graphic dimensions, etc., indicating the graphic shape of the graphic data. Then, binary or multivalued image data is developed as a pattern arranged in a grid having a grid with a predetermined quantization size as a unit. The developed image data (developed image data) is stored in a pattern memory (not shown) or a magnetic disk device 142 in the circuit. In other words, in the occupancy rate calculation unit, the design pattern data is read, and the occupancy rate of the figure in the design pattern is calculated for each cell formed by virtually dividing the inspection area as a cell with a predetermined dimension as a unit, The n-bit occupation ratio data is output to the pattern memory or the magnetic disk device 142. For example, it is preferable to set one square as one pixel. If a resolution of 1/2 ⁸ (= 1/256) is given to one pixel, 1/256 small areas are allocated by the figure area arranged in the pixel, and the occupation ratio in the pixel is set. Calculate. The developed image data is stored in the pattern memory or the magnetic disk device 142 as area-unit image data defined by 8-bit occupancy data for each pixel.

  As an image processing step, the reference image generation circuit 112 receives the developed image data, performs data processing (image processing) on the developed image data, and generates reference image data for comparison with optical image data. The reference image generation circuit 112 is an example of a reference image data generation unit. The reference image generation circuit 112 performs an appropriate filter process on the developed image data.

  Using the developed image data generated as described above, reference image data for comparison with optical image data is generated.

  FIG. 7 is a diagram for explaining the filter processing in the first embodiment. The optical image data (measurement data) obtained from the sensor circuit 106 is in a state in which the filter is activated by the resolution characteristic of the magnifying optical system 104, the aperture effect of the photodiode array 105, or the like, in other words, in an analog state that continuously changes. For this reason, the developed image data, which is the image data on the design side of which the image intensity (shading value) is a digital value, can also be matched to the measurement data by performing a filtering process according to a predetermined model. For example, filter processing such as resizing processing for performing enlargement or reduction processing, corner rounding processing, or blurring processing is performed. In this way, a reference image to be compared with the optical image is created. The created reference image data is sent to the comparison circuit 108. Similarly to the measurement data, the reference image data is, for example, 8-bit unsigned data in each pixel, and the brightness gradation of each pixel is expressed by 0 to 255. The generated reference image data is stored in a memory (not shown) in the reference image generation circuit 112 or the magnetic disk device 142.

  As a comparison process, the comparison circuit 108 compares the optical image data of the corresponding predetermined region with the reference image data for each pixel under a predetermined determination condition. The comparison circuit 108 is an example of a comparison unit. In the comparison circuit 108, first, optical image data for one stripe is input from the stripe pattern memory 146, and the optical image data for one stripe is cut out with the same area size as the reference image. In this case, it goes without saying that the area to be cut out is matched with the area for generating the reference image. The optical image data in which the region sizes are matched is stored in a memory (not shown) in the comparison circuit 108. On the other hand, the generated reference image data of the predetermined area is also stored in another memory (not shown) in the comparison circuit 108. Then, the optical image data and the reference image data in the same region are read out and aligned. Then, the aligned optical image data and reference image data are compared for each pixel according to the determination condition, and the presence or absence of a defect is determined. As the determination condition, for example, a threshold value for comparing the two for each pixel according to a predetermined algorithm and determining the presence or absence of a defect corresponds. Alternatively, for example, a comparison algorithm for comparing the two and determining the presence or absence of a defect is applicable.

  The inspection method described above is a “die to database inspection (die-database inspection)” method. In the optical image acquisition device 150, a plurality of die patterns are formed from the photomask 101 in which the same pattern is formed on a plurality of dies. Each of the optical images may be acquired, and the “die to dei inspection (die-die inspection)” method may be performed in the comparison circuit 108 for comparing the two images.

  In order to perform the inspection process as described above with high accuracy, it is important to continue outputting a stable amount of laser light from the laser light source device 103. However, as described above, since the laser beam is deteriorated by use, maintenance is required. For example, deterioration of a nonlinear crystal (not shown) arranged in the laser light source 178 can be mentioned. When the nonlinear crystal is deteriorated, an operation such as shifting the irradiation position of the fundamental wave to the nonlinear crystal is required. Therefore, in the laser light source device 103, the control circuit 176 controlled by the CPU 171 controls a maintenance operation for automatically maintaining the inside of the laser light source 178. In the first embodiment, the maintenance operation of the laser light source device 103 is managed as the pattern inspection system 100 so that the operation of the inspection process is not hindered as much as possible. Alternatively, the host control computer 200 does not manage, but is managed by at least the higher-level control device 160 so that the operation of the inspection process is not hindered as much as possible. In the first embodiment, in addition, the laser light source device 103 itself can be configured to perform maintenance operations in an emergency in preparation for a failure or communication error of the higher-level control device 160 or the host control computer 200. Hereinafter, a method for controlling the execution timing of the automatic maintenance operation performed by the laser light source device 103 will be described.

  FIG. 8 is a flowchart showing main steps of the maintenance level storing method in the laser light source apparatus according to the first embodiment.

  As the laser status confirmation step (S102), the CPU 171 in the laser light source device 103 controls the control circuit 176 to confirm the state of the laser light output from the laser light source 178. For example, the amount of laser light, the elapsed time since the previous automatic maintenance operation was executed, and the operating state of the laser light source 178 are confirmed. The operating state of the laser light source 178 includes a state such as an automatic maintenance operation, a steady operation, a startup, or a stop. The amount of laser light may be measured by a light amount sensor (not shown) disposed in the laser light source 178. Each confirmed data is stored in the memory 172.

  As a condition check and determination step (S104), the CPU 171 determines the degree of necessity of automatic maintenance operation from the confirmed state of the laser beam. The degree of necessity of automatic maintenance operation is defined by the value of the self-maintenance request flag as an identifier. For example, if the automatic maintenance operation is not necessary, the value “0” is defined as “no self-maintenance request”. If the automatic maintenance operation is urgently required, the value “1” is defined as “urgent automatic maintenance operation required”. If the automatic maintenance operation is required within 5 hours, the value “2” is defined as “automatic maintenance operation required within 5 hours”. If the automatic maintenance operation is required within 24 hours, the value “3” is defined as “automatic maintenance operation required within 24 hours”. If the automatic maintenance operation is necessary within 168 hours, it is defined by the value “4” as “automatic maintenance operation necessary within 168 hours”. In this way, the degree of necessity (maintenance level) of the automatic maintenance operation is identified by the value of the self-maintenance request flag from 0 to 4. The determination method may be determined based on, for example, the degree of deterioration of the amount of laser light, the usage time of the nonlinear crystal, or the like. The correlation between the time required for the automatic maintenance operation and the amount of laser light may be acquired in advance by experiments or the like and stored in the memory 172 or the storage device 175 such as a magnetic disk device. Then, the correlation may be read (referenced) from the memory 172 or the storage device 175 to determine the maintenance level. As a result of the determination, if the automatic maintenance operation is unnecessary, the process proceeds to S106. If an automatic maintenance operation is necessary, the process proceeds to S108.

  As the maintenance level storing step (S106), the CPU 171 overwrites and saves the maintenance level “0” in the memory 172 when the value of the defined self-maintenance request flag is “0” determined in the previous step.

  As the maintenance level storing step (S108), the CPU 171 determines the value of the maintenance level (“1” to “4”) when the value of the defined self-maintenance request flag is “1” to “4”. 4 ”) is overwritten and saved in the memory 172. Further, when the value of the defined self-maintenance request flag is “1”, the CPU 171 stores the self-maintenance request flag occurrence time in the memory 172 as well.

  Then, regardless of whether the process proceeds to either the maintenance level storing step (S106) or the maintenance level storing step (S108), the process returns to S102 and the above steps are repeated. As a result, the laser status is regularly checked and the self-maintenance request flag is updated, and the memory 172 always stores the latest self-maintenance request flag value.

  FIG. 9 is a flowchart showing main steps of the automatic maintenance operation start determination method in the laser light source device according to the first embodiment. The sequence shown in FIG. 9 is processed independently of the sequence shown in FIG.

  As the parameter setting step (S120), a setting time indicating the automatic maintenance operation start time desired by the user and a setting interval indicating the desired automatic maintenance operation execution interval are set in the storage device 175 in the laser light source device 103. Further, a set day of the week indicating the day of the week on which a desired automatic maintenance operation is executed, or a designated day of, for example, one month or several months may be set. If there is a designated flag value (designated identifier), the designated flag value is set. Such parameters may be set by the user in the host control computer 200 or the control device 160 and received by the laser light source device 103 from the host control computer 200 or the control device 160.

  As the local / remote determination step (S122), the CPU 171 operates in a remote mode in which the laser light source device 103 is remotely controlled from the host control device 160 or the host control computer 200 or the laser light source device 103 alone without being controlled from the host. Determine whether you are in local mode. The laser light source device 103 is configured so that the remote mode and the local mode can be selected. In the case of the local mode, the process proceeds to S124. In the case of the remote mode, the process proceeds to S126.

  As a maintenance level check and determination step (S124), in the local mode, the CPU 171 refers to the self-maintenance request flag and the elapsed time since the previous automatic maintenance operation was executed from the memory 172, and the storage device 175 reads the above-mentioned information. It is determined whether or not an automatic maintenance operation is necessary by referring to the parameters. Here, the self-maintenance request flag, the elapsed time since the previous automatic maintenance operation was executed, and each parameter are used for determination according to a maintenance necessity determination sequence described later.

  When the determination process is performed as described above and the automatic maintenance operation is necessary, the process proceeds to S134. If the automatic maintenance operation is unnecessary, the process returns to S122.

  In the maintenance operation execution command presence / absence determination step (S126), in the remote mode, the CPU 171 determines whether a maintenance operation execution command transmitted from the control device 160 has been received (input). If a maintenance operation execution command has been received, the process proceeds to S134. If the maintenance operation execution command has not been received, the process proceeds to S128.

  When the maintenance operation execution command is not received as the maintenance level determination step (S128), the CPU 171 refers to the self-maintenance request flag from the memory 172, and the value of the self-maintenance request flag is other than “1” or “1”. Determine whether. If the value of the self-maintenance request flag is “1”, the process proceeds to S130. If the value of the self-maintenance request flag is other than “1”, the process returns to S122.

  In the maintenance level “1” elapsed time determination step (S130), when the value of the self-maintenance request flag is “1”, the CPU 171 refers to the occurrence time of the self-maintenance request flag value “1” from the memory 172, and It is determined whether or not the threshold value has elapsed. If the predetermined threshold has elapsed, the process proceeds to S132. If the predetermined threshold value has not elapsed, the process returns to S122.

  In the local mode switching step (S132), when the previous process has passed the predetermined threshold, the CPU 171 switches the remote mode to the local mode. Then, the process proceeds to S134.

  As an automatic maintenance operation execution step (S134), the control circuit 176 controlled by the CPU 171 performs control so as to automatically start a maintenance operation for maintaining the inside of the laser light source 178. The laser light source 178 is controlled by the control circuit 176. Execute automatic maintenance operation according to Then, after the automatic maintenance operation is completed, the process returns to S122 and the above-described steps are repeated. As a result, automatic maintenance operation start determination processing is periodically performed in the laser light source device 103.

  As described above, in the local mode, the laser light source device 103 performs the automatic maintenance operation at a time required by its own determination as shown in S124 and S134. In the remote mode, as shown in S126 and S134, when a maintenance operation execution command as an instruction from the host control device 160 or the host control computer 200 is received, an automatic maintenance operation is immediately executed. Further, even in the case where a maintenance operation execution command is not received in preparation for a failure of the host control device 160 or the host control computer 200 or a communication error, the operation of the laser light source device 103 itself is ensured as shown in S128 to S134. Therefore, the automatic maintenance operation is executed after a certain period (threshold) has elapsed.

  FIG. 10 is a flowchart showing main steps of the maintenance operation execution command output determination method in the control device according to the first embodiment.

  As a parameter setting step (S200), a setting time indicating an automatic maintenance operation start time and a setting interval indicating an automatic maintenance operation execution interval are set by the user in the magnetic disk device 109 in the control device 160. Further, a set day of the week indicating the day of the week on which the automatic maintenance operation is executed, or a designated day of, for example, one month or several months may be set. If there is a designated flag value (designated identifier), the designated flag value is set. Such parameters may be set in the host control computer 200 by the user and received by the control device 160 from the host control computer 200.

  As the permission / prohibition mode determination step (S202), the CPU 110 in the control device 160 determines whether the currently set mode is the permission mode or the prohibition mode. A prohibit command for prohibiting the output of the maintenance operation execution command from the host control computer 200 to the control device 160 according to the determination of the control device 160, and a permission command for permitting the output of the maintenance operation execution command according to the determination of the control device 160; Is output, and the control device 160 sets either the permission mode or the prohibition mode in accordance with the command. Unlike the host control computer 200 that controls the entire pattern inspection system 100 by providing a function that is set to either a permission mode or a prohibition mode according to an instruction from the host device side, only a part of the system is controlled. For example, it is possible to limit the control device 160 not to automatically execute the automatic maintenance operation of the laser light source device 103 while the laser light source device 103 is in steady operation during the inspection process. In the prohibit mode, the process returns to S202. In the case of the permission mode, the process proceeds to S204.

  As a data reading step (S204), the CPU 110 reads from the memory 172 of the laser light source device 103 the self-maintenance request flag value, the elapsed time since the previous automatic maintenance operation was executed, and the operating state of the laser light source device 103. Each data is stored in the memory 123.

  In the maintenance operation state determination step (S206), the CPU 110 refers to the operation state of the laser light source device 103 stored in the memory 123, and determines whether or not the operation state of the laser light source device 103 is executing an automatic maintenance operation. . If the laser light source device 103 is currently performing an automatic maintenance operation, there is no need to further execute an automatic maintenance operation, and the process returns to S202. If the laser light source device 103 is not executing the automatic maintenance operation, the process proceeds to S208.

  In the maintenance operation necessity determination step (S208), the CPU 110 refers to the self-maintenance request flag value and the elapsed time since the previous automatic maintenance operation was performed from the memory 123, and sets the parameters set from the magnetic disk device 109. Refer to and determine whether automatic maintenance operation is necessary. Here, the self-maintenance request flag, the elapsed time since the previous automatic maintenance operation was executed, and each parameter are used for determination according to a maintenance necessity determination sequence described later. If it is determined that the automatic maintenance operation is unnecessary, the process returns to S202. If it is determined that the automatic maintenance operation is necessary, the process proceeds to S210.

  In the maintenance operation execution command output step (S210), when it is determined that the automatic maintenance operation is necessary in the previous step, the CPU 110 outputs a maintenance operation execution command that triggers the laser light source device 103 to execute the automatic maintenance operation. Output to the device 103. Then, after output, the process returns to S202, and the above-described steps are repeated. As a result, the necessity determination process for the automatic maintenance operation of the laser light source device 103 and the maintenance operation execution command output process are periodically performed in the control device 160.

  FIG. 11 is a flowchart showing main steps of the command processing method in the control device according to the first embodiment. The sequence shown in FIG. 11 is processed independently of the sequence shown in FIG.

  As a command input determination step (S222), the CPU 110 in the control device 160 determines whether any command is input from the host control computer 200. If no command is input, the process returns to S222. If any command is input, the process proceeds to S224.

  In the light source information request instruction command determination step (S224), when it is determined that any command is input in the previous step, the CPU 110 determines whether the command is a light source information request instruction command. If it is a light source information request instruction command, the process proceeds to S226. If it is not a light source information request instruction command, the process proceeds to S230.

  In the light source information request command output step (S 226), when it is a light source information request instruction command, the CPU 110 outputs a light source information request command to the laser light source device 103. Then, as the light source information from the laser light source device 103, the self-maintenance request flag value, the elapsed time since the previous automatic maintenance operation was executed, and the operation state of the laser light source device 103 are read from the memory 172 of the laser light source device 103. Each data is stored in the memory 123.

  In the data return step (S228), the CPU 110 returns the light source information received from the laser light source device 103 to the host control computer 200. When the reply of the light source information is completed, the process returns to S222.

  In the maintenance operation execution instruction command determination step (S230), when the input command is not a light source information request instruction command, the CPU 110 determines whether the command is a maintenance operation execution instruction command. If it is a maintenance operation execution instruction command, the process proceeds to S232. If it is not a maintenance operation execution instruction command, the process proceeds to S234.

  In the maintenance operation execution command output step (S232), when it is a maintenance operation execution instruction command, the CPU 110 outputs a maintenance operation execution command to the laser light source device 103. Here, regardless of the sequence in FIG. 10, in response to an instruction from the host control computer 200, a maintenance operation execution command is immediately output to the laser light source device 103. When the output of the maintenance operation execution command is completed, the process returns to S222.

  In the prohibited command determination step (S234), when the input command is not a maintenance operation execution instruction command, the CPU 110 determines whether the command is the above-described prohibited command. If it is a prohibited command, the process proceeds to S236. If it is not a prohibited command, the process proceeds to S238.

  In the prohibited command setting step (S236), when the command is a prohibited command, the CPU 110 sets the prohibited mode according to the command. Such setting is performed by storing “0” in the memory 123 as an automatic maintenance execution permission flag. When the setting is completed, the process returns to S222.

  In the permission command determination step (S238), when the input command is not a prohibited command, the CPU 110 determines whether the command is the permission command described above. If it is a permission command, the process proceeds to S240. If it is not a permission command, the process returns to S222.

  In the permission command setting step (S240), if the command is a permission command, the CPU 110 sets the permission mode according to the command. Such setting is performed by storing “1” as an automatic maintenance execution permission flag in the memory 123. When the setting is completed, the process returns to S222.

  As described above, command processing is periodically repeated in the control device 160.

  FIG. 12 is a flowchart showing the steps of the inspection program in the host control computer in the first embodiment.

  In the prohibit command output step (S302), when the inspection program starts, the CPU 202 in the host control computer 200 first outputs the prohibit command described above to the control device 160. By setting the control device 160 to the prohibit mode by such a prohibit command, automatic maintenance of the laser light source device 103 can be prevented from being executed without permission during the inspection process.

  As the inspection processing execution step (S304), the pattern inspection system 100 performs the above-described die-database inspection or die-die inspection using each device. In parallel with the inspection processing, as will be described later, the CPU 202 in the host control computer 200 outputs a maintenance operation execution instruction command for instructing the control device 160 to execute the automatic maintenance operation of the laser light source device 103. A determination sequence is performed for this purpose.

  As the permission command output step (S306), when the inspection process of the previous step is completed, the CPU 202 in the host control computer 200 outputs the above-described permission command to the control device 160. When the control device 160 is set to the permission mode by the permission command, automatic maintenance of the laser light source device 103 can be executed based on the determination of the control device 160. Since the inspection process has already been completed, the control device 160 may make a determination.

  FIG. 13 is a flowchart showing main steps of the maintenance operation execution instruction command output determination method in the host control computer executed in parallel with the inspection processing execution step (S304) of FIG. The sequence shown in FIG. 13 is processed independently of the sequence shown in FIG.

  First, as a parameter setting step (S320), a setting time indicating an automatic maintenance operation start time and a setting interval indicating an automatic maintenance operation execution interval are set by the user in the magnetic disk device 206 in the host control computer 200. Further, a set day of the week indicating the day of the week on which the automatic maintenance operation is executed, or a designated day of, for example, one month or several months may be set. If there is a designated flag value (designated identifier), the designated flag value is set. Such parameters may be set by the user in the control device 160 and received by the host control computer 200 from the control device 160. The parameter setting step (S320) is preferably performed in advance, not after the inspection processing execution step (S304).

  As the data reading step (S322), the CPU 202, via the control device 160, reads the self-maintenance request flag value from the memory 172 of the laser light source device 103, the elapsed time since the previous automatic maintenance operation, and the laser light source device 103. Read the operating status. Each data is stored in the memory 204.

  In the maintenance operation state determination step (S324), the CPU 202 refers to the operation state of the laser light source device 103 stored in the memory 204 and determines whether or not the operation state of the laser light source device 103 is executing an automatic maintenance operation. . If the laser light source device 103 is currently performing an automatic maintenance operation, there is no need to further execute an automatic maintenance operation, and the process returns to S322. If the laser light source device 103 is not executing the automatic maintenance operation, the process proceeds to S326.

  As the inspection state determination step (S326), the CPU 202 determines whether the inspection process is currently being executed. If the optical image acquisition device 150 actually stops the laser beam for the automatic maintenance operation while taking an optical image of the inspection stripe 20 of the photomask 101, an image cannot be obtained and the inspection process is wasted. Therefore, it is difficult to stop the laser light except in an emergency. Therefore, first, it is determined whether or not the inspection process is being executed. In particular, it is desirable in terms of system operation to avoid the automatic maintenance operation during imaging of the inspection stripe 20 which is an image acquisition unit. If the inspection process is being executed, the process proceeds to S330. If the inspection process is not being executed, the process proceeds to S328.

  In the maintenance operation necessity determination step (S328), when it is determined that the inspection process is not being executed in the previous step, the CPU 202 has elapsed from the execution of the self-maintenance request flag value and the previous automatic maintenance operation from the memory 204. By referring to the time and referring to the parameters set from the magnetic disk device 206, it is determined whether or not an automatic maintenance operation is necessary. Here, the self-maintenance request flag, the elapsed time since the previous automatic maintenance operation was executed, and each parameter are used for determination according to a maintenance necessity determination sequence described later. If it is determined that the automatic maintenance operation is unnecessary, the process returns to S322. If it is determined that the automatic maintenance operation is necessary, the process proceeds to S332.

  When it is determined as the maintenance level determination step (S330) that the inspection process is being executed in the previous step, the CPU 202 refers to the self-maintenance request flag from the memory 204 and determines whether the value of the self-maintenance request flag is “1”. It is determined whether it is other than “1”. If the value of the self-maintenance request flag is “1”, the inspection process is interrupted and the process proceeds to S332. If the value of the self-maintenance request flag is other than “1”, the process returns to S322.

  In the maintenance operation execution command output instruction step (S332), when it is determined that the automatic maintenance operation is necessary up to the previous step, the CPU 202 issues a maintenance operation execution command that triggers the laser light source device 103 to execute the automatic maintenance operation. In order to output the laser light source device 103, a maintenance operation execution instruction command is output to the control device 160. Then, after output, the process returns to S322, and the above-described steps are repeated. As a result, in the host control computer 200, the necessity determination process for the automatic maintenance operation of the laser light source device 103 and the maintenance operation execution instruction command output process are periodically performed.

  FIG. 14 is a flowchart showing main steps of the maintenance necessity determination method according to the first embodiment. The maintenance necessity determination sequence shown in FIG. 14 is executed in the host control computer 200, the control device 160 in the permission mode, and the laser light source device 103 in the local mode.

  The host control computer 200, the control device 160, and the laser light source device 103 each have a time designation mode (first judgment mode), an interval designation mode (second judgment mode), and a flag designation mode (third) as judgment modes. At least one determination mode). Hereinafter, a description will be given of a case where the processing is executed using the CPU 202, the memory 204, and the magnetic disk device 206 in the host control computer 200. When executed in the control device 160, the CPU 202, the memory 204, and the magnetic disk device 206 may be read as the CPU 110, the memory 123, and the magnetic disk device 109. When executed in the laser light source device 103, the CPU 202, the memory 204, and the magnetic disk device 206 may be read as the CPU 171, the memory 172, and the storage device (magnetic disk device) 175.

  The time designation mode is implemented in S10 to S18 in FIG. The interval designation mode is implemented in S20 to S22 of FIG. The flag designation mode is implemented in S30 to S32 of FIG. The pattern inspection system 100 is configured such that these modes can be selected as appropriate when all these determination modes are installed. That is, any one mode may be set, and two or more modes may be set. Thus, when all of these modes are installed, they can be used in appropriate combinations. Hereinafter, a sequence when all of these modes are installed will be described.

  As the time designation mode determination step (S10), the CPU 202 determines the presence or absence of the time designation mode. If the time designation mode is not set, it is determined that there is no time designation mode, and the process proceeds to S20. If the time designation mode is set, it is determined that the time designation mode is present, and the process proceeds to S12. Alternatively, for example, the CPU 202 reads the designated time set from the magnetic disk device 206, determines that there is no time designation mode if the designated time is not set, and if the designated time is set, the time designation mode is present. May be determined.

  As the designated time determination step (S12), the CPU 202 reads the designated time set from the magnetic disk device 206, and determines whether or not the current time is the designated time. Here, it is preferable to include the case where the current time is within a predetermined range including the designated time. Since this process is not always determined at the specified time, it can be determined as the specified time even if it is slightly deviated from the specified time by including the case where it is within a predetermined range including the specified time. . If the current time is not the specified time, the process proceeds to S20. If the current time is the specified time, the process proceeds to S14.

  In the week / month unit designation mode presence / absence judgment step (S14), when the designated time is judged in the previous step, the CPU 202 reads the designated day of the week and the designated day from the magnetic disk device 206, and the designated day of the week or designated day is set. Determine whether or not. If the designated day of the week or designated day is set, it is determined that the week / month unit designation mode is present, and the process proceeds to S16. If neither the designated day of the week nor the designated day is set, it is determined that there is no week / month unit designation mode, and the process proceeds to S18. By providing a weekly / monthly designation mode, it is possible to specify a day of the week, a day of the week for every other week, a date designation once a month, and the like.

  In the designated day / designated date determination step (S16), when it is determined in the previous step that the week / month unit designation mode is present, the CPU 202 reads the designated day of the week and the designated date from the magnetic disk device 206 and determines the current day (determination). Whether (day) is a designated day of the week or a designated day is determined. If the determination date is a specified day of the week or a specified date, it is determined that maintenance is necessary. If the determination date is neither the specified day of the week nor the specified date, the process proceeds to S20.

  When it is determined in the difference determination step (S18) that the week / month unit designation mode is not present in the week / month unit designation mode presence / absence determination step (S14), the CPU 202 reads the designated interval set from the magnetic disk device 206. The elapsed time since the previous automatic maintenance operation was performed is read from the memory 204. Then, the CPU 202 calculates a difference obtained by subtracting the elapsed time from the specified interval, and determines whether the difference is less than 24 hours. If it is less than 24 hours, it is determined that maintenance is necessary. If it is not less than 24 hours, the process proceeds to S20. If the specified interval is less than 24 hours, the automatic maintenance operation is performed every day, every day if it is 24 hours or more and less than 48 hours, and every other day if it is 48 hours or more and less than 72 hours.

  FIG. 15 is a diagram showing an example of an execution schedule of automatic maintenance operation in the time designation mode in the first embodiment. FIG. 15 shows a case where there is no week / month unit designation mode. Further, the case where the interval designation mode and the flag designation mode are not set is shown. FIG. 15 shows an example in which the designated time (maintenance time) is set to 6 am (6:00 AM) and the designated interval (maintenance start time interval) is set to 12 hours (12H). At maintenance time B, which is 24 hours after the date and time when the previous automatic maintenance was executed, indicated by maintenance time A, the specified time is 24 and the difference obtained by subtracting the elapsed time since the previous automatic maintenance was executed from the specified interval is 24. Since it is less than the time, it is determined that maintenance is necessary at maintenance time B, and automatic maintenance is performed. Similarly, the maintenance time C after 24 hours from the maintenance time B is the specified time, and the difference obtained by subtracting the elapsed time from the date and time (maintenance time B) when the previous automatic maintenance was executed from the specified interval is 24 hours. Therefore, it is determined that maintenance is necessary at the maintenance time C, and automatic maintenance is executed. Here, since the designated interval is less than 24 hours, a case where automatic maintenance is always performed at the designated time is shown.

  FIG. 16 is a diagram showing another example of the execution schedule of the automatic maintenance operation in the time designation mode in the first embodiment. FIG. 16 shows the case where there is no week / month unit designation mode. Further, the case where the interval designation mode and the flag designation mode are not set is shown. FIG. 16 shows an example in which the designated time (maintenance time) is 6:00 am (6:00 AM) and the designated interval (maintenance start time interval) is set to 50 hours (50H). The maintenance time B, which is 24 hours after the date and time when the previous automatic maintenance was performed, indicated by the maintenance time A is the specified time, but the difference (remaining) from the specified interval that is the elapsed time since the previous automatic maintenance was performed The maintenance start time) is 26 hours, which is 24 hours or longer. Therefore, at the maintenance time B, it is determined that there is no need for maintenance, and the maintenance is not carried out without automatic maintenance. The maintenance time C after 24 hours from the maintenance time B is the specified time, and the difference obtained by subtracting the elapsed time from the date and time (maintenance time A) when the previous automatic maintenance was executed from the specified interval is 2 hours. Because it is less than 24 hours, it is determined that maintenance is necessary at maintenance time C, and automatic maintenance is performed.

  FIG. 17 is a diagram showing another example of an execution schedule of the automatic maintenance operation in the time designation mode in the first embodiment. FIG. 17 shows a case where there is no week / month unit designation mode. Further, the case where the interval designation mode and the flag designation mode are not set is shown. FIG. 17 shows an example in which the designated time (maintenance time) is set to 6 am (6:00 AM) and the designated interval (maintenance start time interval) is set to 60 hours (60H). The maintenance time B, which is 24 hours after the date and time when the previous automatic maintenance was performed, indicated by the maintenance time A is the specified time, but the difference (remaining) from the specified interval that is the elapsed time since the previous automatic maintenance was performed (Maintenance start time) is 36 hours, which is 24 hours or longer. Therefore, at the time of maintenance time B, it is determined that maintenance is not necessary, and automatic maintenance is not performed. The maintenance time C after 24 hours from the maintenance time B is the specified time, and the difference obtained by subtracting the elapsed time from the date and time (maintenance time A) when the previous automatic maintenance was executed from the specified interval is 12 hours. Because it is less than 24 hours, it is determined that maintenance is necessary at maintenance time C, and automatic maintenance is performed. The maintenance time D after 24 hours from the maintenance time C is the specified time, but the difference (remaining maintenance start time) obtained by subtracting the elapsed time from the maintenance time C when the previous automatic maintenance was executed from the specified interval. Since it is 36 hours and is more than 24 hours, it is determined that maintenance is not necessary at the maintenance time D, and the automatic maintenance is not performed. The maintenance time E after 24 hours from the maintenance time D is the specified time, and the difference obtained by subtracting the elapsed time from the date and time (maintenance time C) when the previous automatic maintenance was executed from the specified interval is 12 hours. Because it is less than 24 hours, it is determined that maintenance is necessary at the maintenance time E, and automatic maintenance is executed. In FIG. 17, since there is no flag designation mode to be described later, even if the self-maintenance request flag indicates a value between “2” and “4” between maintenance times A and B, automatic maintenance is not executed. . Next, the interval designation mode will be described.

  As the interval designation mode determination step (S20), the CPU 202 determines whether or not there is an interval designation mode. If the interval designation mode is not set, it is determined that there is no interval designation mode, and the process proceeds to S30. If the interval designation mode is set, it is determined that the interval designation mode is present, and the process proceeds to S22. By providing the interval designation mode, it is possible to designate the usage time in terms of design or experience, and the apparatus can be used without maintenance to the maximum extent.

  In the difference determination step (S22), when it is determined that the interval designation mode is present, the CPU 202 reads the designated interval set from the magnetic disk device 206, and the elapsed time since the previous automatic maintenance operation was performed from the memory 204. Is read. Then, the CPU 202 calculates a difference obtained by subtracting the elapsed time from the specified interval, and determines whether the difference is 0 hour or less (including negative). If it is less than 0 hours, that is, if the elapsed time has reached the specified interval, it is determined that maintenance is necessary. If it is 0 hour or longer, the process proceeds to S30.

  FIG. 18 is a diagram illustrating an example of an execution schedule of the automatic maintenance operation in the interval designation mode in the first embodiment. FIG. 18 shows a case where the time designation mode and the flag designation mode are not set. FIG. 18 shows an example in which the specified interval (maintenance start time interval) is set to 50 hours (50H). The maintenance time B after 24 hours from the date and time when the previous automatic maintenance was performed indicated by the maintenance time A was the specified time in the above-described example, but since the specified time is not set here, the maintenance operation is not executed. Similarly, the maintenance operation is not executed at the maintenance time C after 24 hours from the maintenance time B. In FIG. 18, when 50 hours have passed since the date and time when the previous automatic maintenance indicated by maintenance time A was executed, the elapsed time has reached the specified interval, so that it is determined that maintenance is necessary, and automatic maintenance is executed.

  FIG. 19 is a diagram illustrating an example of an execution schedule of an automatic maintenance operation in the combination of the time specification mode and the interval specification mode in the first embodiment. FIG. 19 shows a case where the flag designation mode is not set. FIG. 19 shows a case where the week / month unit designation mode is not used. FIG. 19 shows an example in which the designated time (maintenance time) is set to 6 am (6:00 AM) and the designated interval (maintenance start time interval) is set to 12 hours (12H). When the elapsed time reaches the specified interval after 12 hours from the date and time when the previous automatic maintenance indicated by the maintenance time A is executed, it is determined that maintenance is necessary in the interval specifying mode, and automatic maintenance is executed. The maintenance time B after 24 hours from the maintenance time A is the designated time, and 12 hours have passed since 12 hours before the previous automatic maintenance was executed, and the elapsed time has reached the designated interval. Therefore, it is determined that maintenance is necessary in both the time designation mode and the interval designation mode. However, in FIG. 14, since the determination in the time designation mode is executed first, it is determined here that the time designation mode is in need of maintenance, and automatic maintenance is executed. Then, after 12 hours have passed since the date and time when the previous automatic maintenance indicated by maintenance time B was executed, the elapsed time has reached the specified interval, so that it is determined that there is a need for maintenance in the interval specifying mode, and automatic maintenance is executed. The maintenance time C, which is 24 hours after the maintenance time B, is the designated time, 12 hours have passed since 12 hours before the previous automatic maintenance was executed, and the elapsed time has reached the designated interval. Again, since the determination in the time specification mode is executed first, it is determined here that there is a need for maintenance as the time specification mode, and automatic maintenance is executed. Next, the flag designation mode will be described.

  As the flag designation mode determination step (S30), the CPU 202 determines the presence / absence of the flag designation mode. When the flag designation mode is not set, it is determined that there is no flag designation mode, and it is determined that maintenance is not necessary. If the flag designation mode is set, it is determined that the flag designation mode is present, and the process proceeds to S32. Alternatively, for example, the CPU 202 reads the designation flag set from the magnetic disk device 206, determines that the flag designation mode is not present when the designation flag is not set, and has the flag designation mode when the designation flag is set. May be determined.

  When it is determined in the specified level determination step (S 32) that the flag specification mode is present, the CPU 202 reads the specified flag set from the magnetic disk device 206 and reads the value of the self-maintenance request flag from the memory 204. Then, the CPU 202 determines whether or not the value of the self-maintenance request flag is a maintenance level designated by the designation flag. If it is the maintenance level, it is determined that maintenance is necessary. If it is not the maintenance level, it is determined that there is no need for maintenance. For example, the designation flags are “1” and “2”. In this case, if the value of the self-maintenance request flag is “0”, “3” or “4”, it is determined that there is no need for maintenance. By setting the specified level, it is possible to arbitrarily determine the user setting according to the degree of necessity indicated by the self-maintenance request flag. It can also be determined that maintenance is necessary when the designated flag is at a highly urgent maintenance level. For example, if the designated flag is “3”, it can be determined that there is a need for maintenance when the value of the self-retention request flag of the maintenance level with higher urgency is “1”, “2”, “3”. . Further, for example, when the maintenance necessity judgment sequence shown in FIG. 14 is executed by the host control computer 200, the host control computer 200 performs pattern inspection of the photomask 101 according to the degree of necessity indicated by the self-maintenance request flag. It can be determined whether the maintenance operation execution command is output to the control device 160 before the operation is performed, or whether the maintenance operation execution command is output to the control device 160 after the pattern inspection of the photomask 101 is performed.

  FIG. 20 is a diagram illustrating an example of an execution schedule of an automatic maintenance operation in the combination of the time specification mode and the flag specification mode in the first embodiment. FIG. 20 shows a case where the interval designation mode is not set. FIG. 20 shows the case where the week / month unit designation mode is not used. In FIG. 20, the designated time (maintenance time) is 6:00 AM (6:00 AM), the designated interval (maintenance start time interval) is set to 60 hours (60H), and the designation flag is set to “1” and “2”. An example of setting is shown. The value of the self-maintenance request flag specified in the specified flag is read after 18 hours from the date and time when the previous automatic maintenance indicated by maintenance time A was executed, so it is determined that there is a need for maintenance and automatic maintenance is executed. Is done. And, at the maintenance time B after 24 hours from the maintenance time A, it is the designated time, but only 6 hours have passed since 6 hours before (18 hours after the maintenance time A) the previous automatic maintenance was executed, Since the difference (remaining maintenance start time) obtained by subtracting the elapsed time since the previous automatic maintenance from the specified interval is 54 hours and is 24 hours or more, it is determined that maintenance is not necessary at the maintenance time B, It is deferred without automatic maintenance. The maintenance time C after 24 hours from the maintenance time B is the specified time, but is a difference obtained by subtracting the elapsed time from the date and time (18 hours after the maintenance time A) when the previous automatic maintenance was executed from the specified interval. Therefore, it is determined that there is no need for maintenance at the time of maintenance time B, and the maintenance is not carried out without automatic maintenance. The maintenance time D, which is 24 hours after the maintenance time C, is a specified time, and is a difference (remaining maintenance) that indicates the elapsed time from the date and time (18 hours after the maintenance time A) when the previous automatic maintenance was executed from the specified interval. Since the start time is 6 hours and less than 24 hours, it is determined that maintenance is necessary at the maintenance time D, and automatic maintenance is performed. The maintenance time E after 24 hours from the maintenance time D is the specified time, but the difference obtained by subtracting the elapsed time from the date and time (maintenance time D) when the previous automatic maintenance was executed from the specified interval is 24 hours or more. Therefore, at the maintenance time B, it is determined that there is no need for maintenance, and the automatic maintenance is not performed, and the operation is postponed.

  FIG. 21 is a diagram showing an example of an execution schedule of an automatic maintenance operation in a combination of a time specification mode with a week / month unit specification mode and a flag specification mode in the first exemplary embodiment. If the weekly / monthly designation mode is not set, automatic maintenance will not be performed unless the difference obtained by subtracting the elapsed time from the date and time when the previous automatic maintenance was executed from the designated interval is less than 24 hours even if the designated time is reached. It will not be executed. However, if the weekly designation mode is set, the automatic maintenance can be executed on a specific day of the week (designated day). For example, FIG. 21 shows an example in which automatic maintenance is executed every Monday. In such a case, for example, when the designated day of the week comes, the CPU 202 needs an automatic maintenance operation at the designated time regardless of the difference obtained by subtracting the elapsed time from the date and time when the previous automatic maintenance was executed from the designated interval. Judge that there is. Then, automatic maintenance is executed. Alternatively, if the monthly unit designation mode is set, the automatic maintenance can be performed on a specific day (designated day). In such a case, for example, when the specified date is reached, the CPU 202 requires an automatic maintenance operation at the specified time regardless of the difference obtained by subtracting the elapsed time from the date and time when the previous automatic maintenance was executed from the specified interval. Judge that there is. Then, automatic maintenance is executed. Further, if the difference is 168 hours or more (one week or more) in the weekly designation mode, it is determined that there is no need for maintenance, and the maintenance operation can be performed every other week. Similarly, in the monthly unit designation mode, if the difference is 744 hours or more (one month or more), it is determined that there is no need for maintenance, and the maintenance operation can be performed every other month.

  FIG. 22 is a conceptual diagram showing another configuration of the pattern inspection system in the first embodiment. 22 is the same as FIG. 1 except that a laser light source device 303 (second laser light source device) and mirrors 304 and 306 are further added. The internal configuration of the laser light source device 303 is the same as that of the laser light source device 103 (first laser light source device). The mirror 304 is movably arranged. In FIG. 22, when the laser light source device 103 cannot generate laser light due to a failure or the like, the laser light source device 303 generates laser light instead. In such a configuration, it is also preferable that the above-described sequences for the automatic maintenance operation are executed for the standby laser light source device 303 similarly to the laser light source device 103. In other words, the configuration and operation of the content in which the laser light source device 103 described above in the first embodiment is replaced with the laser light source device 303 are performed.

  As described above, also in the laser light source device 303, the self-maintenance request flag (second identifier) indicating the degree of necessity of the maintenance operation of the laser light source device 303 and the elapsed time since the previous maintenance operation (second progress). Time) and get. Then, similarly to the laser light source device 103, the control device 160 periodically inputs a self-maintenance request flag and an elapsed time from the laser light source device, and the laser light source based on at least one of the self-maintenance request flag and the elapsed time. The apparatus 303 outputs a maintenance operation execution command (second maintenance operation execution command) that becomes a trigger for executing the maintenance operation to the laser light source device 303. The laser light source device 303 receives a maintenance operation execution command from the control device 160, and executes the maintenance operation of the laser light source device 303 based on the maintenance operation execution command.

  With this configuration, as with the laser light source device 103, the automatic maintenance operation can be executed for the standby laser light source device 303 so as not to disturb the operation of the pattern inspection system. Although two laser light source devices are shown in FIG. 22, three or more laser light source devices may be used. As with the laser light source device 103, the above-described sequences for the automatic maintenance operation are also preferably executed for the plurality of laser light source devices.

  As described above, in the first embodiment, the timing for executing self-maintenance can be controlled from the host control device 160 and the host control computer 200 based on the status of the laser light source and the operating status of the system. The pattern inspection system 100 includes a mode in which self-maintenance is performed at a certain time, a mode in which the maximum use time is specified for maximum use of the light source, and self-maintenance is performed when the time is exceeded. Modes for self-maintenance according to a maintenance request are provided, and these modes can be used in combination. Thereby, the timing of self-maintenance of the light source can be determined in consideration of the operation of the apparatus so as not to affect the operation time of the system as much as possible.

  Further, as described above, since the self-maintenance request flag is identified in a plurality of degrees including the maintenance level indicating the urgency state, the self-maintenance request flag is immediately determined according to the urgency according to the maintenance level and the operation status of the system. You can choose whether to do it after the process, after the process, or before the process.

  With this configuration, it is possible to schedule self-maintenance considering the operation schedule of the device, and it is possible to say that self-maintenance is performed at night when work is not performed, or that self-maintenance is performed once a week at a fixed time Can be.

  In addition, if the necessity of self-maintenance occurs during device operation due to trouble, etc., the information including the urgency of self-maintenance is given to the upper system, so that the upper side can respond according to the contents of the processing currently being executed. Therefore, it is possible to cope with whether the self-maintenance is to be executed immediately, to postpone it, or to do it first, so that the apparatus can be operated efficiently.

  As described above, it is possible to operate the apparatus so as not to affect the operating rate of the apparatus as much as possible while keeping the state of the laser light source optimal.

  FIG. 23 is a diagram for explaining another optical image acquisition method. In the configuration of FIG. 2, the photodiode array 105 that simultaneously enters the number of pixels of the scan width W is used. However, the configuration is not limited to this. Each time a movement with a constant pitch is detected by the laser interferometer, the laser beam is scanned in the Y direction by a laser scanning optical device (not shown) in the Y direction, and transmitted light or reflected light is detected to a predetermined size. A method of acquiring a two-dimensional image for each area may be used.

  In the above description, each sequence described in “˜process” is described as configured by a program operable by a computer, but is not limited thereto. The operation content described in “˜process” may be configured by hardware such as an electric circuit. Alternatively, it may be implemented by a 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 memory of each device. Further, for example, the table control circuit 114, the development circuit 111, the reference image generation circuit 112, the position circuit 107, or the comparison circuit 108, which perform processing necessary for the inspection itself, may be configured by an electrical circuit. It may be realized as software that can be processed by the CPU 110. 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. For example, although the case where transmitted light is used has been described in the above-described embodiment, reflected light or transmitted light and reflected light may be used simultaneously. Needless to say, when the reflected light is used, the pixel value obtained from the transmissive part and the pixel value obtained from the light-shielding part are reversed.

  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 systems or pattern inspection methods that include the elements of the present invention and that can be appropriately modified by those skilled in the art are included in the scope of the present invention.

DESCRIPTION OF SYMBOLS 100 Pattern inspection system 101 Photomask 102 XY (theta) table 103,303 Laser light source device 104 Magnification optical system 105 Photodiode array 106 Sensor circuit 107 Position circuit 108 Comparison circuit 109,142,206 Magnetic disk device 110,141,171,202 CPU
111 development circuit 112 reference image generation circuit 115, 145 magnetic tape device 121, 143 I / F circuit 122, 132, 172, 204 memory 140 comparison device 150 optical image acquisition device 160 control device 178 laser light source 200 host control computer

Claims (11)

A laser light source device for generating laser light;
An optical image acquisition device that illuminates the laser beam onto the inspection sample on which a pattern is formed, and acquires an optical image of the pattern;
A comparison device for inputting the optical image and comparing the optical image with a comparison target image;
A control device for controlling the laser light source device and the optical image acquisition device;
With
The laser light source device acquires an identifier indicating the degree of necessity of the maintenance operation of the laser light source device and an elapsed time since the previous maintenance operation,
The control device periodically inputs the identifier and the elapsed time from the laser light source device, and a trigger for the laser light source device to perform a maintenance operation based on at least one of the identifier and the elapsed time; A maintenance operation execution command is output to the laser light source device,
The pattern inspection system, wherein the laser light source device inputs the maintenance operation execution command from the control device and executes a maintenance operation of the laser light source device based on the maintenance operation execution command. The controller is
When the designated time and the designated interval are set and the designated time is the difference obtained by subtracting the elapsed time from the designated interval is less than 24 hours, it is determined that the maintenance operation of the laser light source device is necessary. A first determination mode to
A second determination mode for determining that a maintenance operation of the laser light source device is necessary when the specified interval is set and a difference obtained by subtracting the elapsed time from the specified interval is 0 or less;
A third determination mode for determining that a maintenance operation of the laser light source device is necessary when a specified identifier is set and the identifier is the specified identifier;
The pattern inspection system according to claim 1, wherein the maintenance operation execution command is output according to a result determined according to the at least one determination mode.   In the first determination mode, at least one of a designated day of the week and a designated day can be set, and when at least one of the designated day of the week and a designated day is set, the laser light source regardless of the difference. 3. The pattern inspection system according to claim 2, wherein it is determined that a maintenance operation of the apparatus is necessary.   The control device and the comparison device are controlled to perform pattern inspection of the sample to be inspected, and the identifier and the elapsed time are periodically input from the laser light source device via the control device, and the identifier And a host device for controlling the control device to output the maintenance operation execution command from the control device to the laser light source device based on at least one of the elapsed time and the elapsed time. The pattern inspection system in any one of 1-3. The host device controls the prohibit command for prohibiting the output of the maintenance operation execution command by the determination of the control device and the permission command for permitting the output of the maintenance operation execution command by the determination of the control device. Output to the device,
The control device does not output the maintenance operation execution command at the judgment of the control device after inputting the prohibit command and until the permission command is input, and outputs the maintenance operation execution command by the host device. 5. The pattern inspection system according to claim 4, wherein the maintenance operation execution command is output when controlled to do so. The host device is
When the designated time and the designated interval are set and the designated time is the difference obtained by subtracting the elapsed time from the designated interval is less than 24 hours, it is determined that the maintenance operation of the laser light source device is necessary. A first determination mode to
A second determination mode for determining that a maintenance operation of the laser light source device is necessary when the specified interval is set and a difference obtained by subtracting the elapsed time from the specified interval is 0 or less;
A third determination mode for determining that a maintenance operation of the laser light source device is necessary when a specified identifier is set and the identifier is the specified identifier;
6. The pattern according to claim 4, further comprising: controlling the control device to output the maintenance operation execution command according to a result determined according to the at least one determination mode. Inspection system.   The host device, depending on the degree of necessity indicated by the identifier, causes the control device to output the maintenance operation execution command before performing pattern inspection of the sample to be inspected, or performs pattern inspection of the sample to be inspected. 7. The pattern inspection system according to claim 4, wherein it is determined whether or not to output the maintenance operation execution command to the control device after performing the operation.   When the maintenance operation execution command is not input for a predetermined period of time while the identifier indicates that the maintenance operation is most necessary, the laser light source device, regardless of whether the maintenance operation execution command is input or not. The pattern inspection system according to claim 1, wherein an operation is executed. When the laser light source device is a first laser light source device, the laser light source device further includes a second laser light source device that generates laser light that can be switched with the laser light of the first laser light source device,
The second laser light source device obtains a second identifier indicating the degree of necessity of the maintenance operation of the second laser light source device and a second elapsed time since the previous maintenance operation was performed,
The control device periodically inputs the second identifier and the second elapsed time from the second laser light source device, and at least one of the second identifier and the second elapsed time. A second maintenance operation execution command serving as a trigger for the second laser light source device to perform a maintenance operation based on the second laser light source device,
The second laser light source device inputs the second maintenance operation execution command from the control device, and executes the maintenance operation of the second laser light source device based on the second maintenance operation execution command. The pattern inspection system according to claim 1, wherein:   When the specified day of the week is set in the first determination mode, it is determined that the maintenance operation of the laser light source device is necessary when the difference is less than 168 hours, and the maintenance operation is performed when the difference is less than 168 hours. The pattern inspection system according to claim 2, wherein a maintenance operation is possible on a specified day every other week.   When the designated date is set in the first determination mode, it is determined that the maintenance operation of the laser light source device is necessary when the difference is less than 744 hours, and the maintenance operation is performed when the difference is less than 744 hours. The pattern inspection system according to claim 2, wherein a maintenance operation is possible on designated days every other month.

Images