JP2017037006A - Defect measurement device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a defect measurement device capable of quickly and appropriately measuring and discriminating defects.SOLUTION: A defect measurement device includes: a first image capturing unit (line sensor camera) 210 having a first image capturing system for photographing an object; a second image capturing unit (confocal microscope) 250 provided with a second image capturing system different from the first image capturing system and configured to photograph the object; and a defect information acquisition unit configured to perform a first acquisition process for obtaining a position of a defect on the object based on a result of photographing a target area of the object using the first image capturing unit 210, and a second acquisition process for acquiring height-directional information of the defect, whose position has been obtained, using the second image capturing unit 250.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an apparatus for measuring a defect existing in an object to be imaged, and more particularly to an apparatus for detecting and measuring a defect present in a mold or the like.

  2. Description of the Related Art Conventionally, an apparatus for detecting a defect, measuring the size, shape, or measuring a defect is known. In particular, there is one that measures at the confocal position in order to accurately measure the depth and height of the defect (see, for example, Patent Document 1). Since this apparatus can detect only a focused portion, it can obtain a high-resolution and high-contrast image without being affected by unnecessary scattered light.

  There has also been proposed an apparatus that can accurately detect a directional defect by irradiating light from different angles (see, for example, Patent Document 2). Although this device can also detect defects accurately, the defect is measured every time a defect is detected while discovering the defect, so it takes time to acquire the entire defect of the object to be imaged. It was.

  Furthermore, an apparatus for comparing a pattern imaged by a first light receiving element with a pattern imaged by a second light receiving element has also been proposed (see, for example, Patent Document 3).

JP-A-5-164527 JP 2010-181317 A JP 2000-137003 A

  Since the apparatus disclosed in Patent Document 1 described above can capture a defect with high resolution, the position and shape of the defect can be accurately acquired. However, when the imaging target is large, it takes a long time to scan all of the imaging target.

  Further, the apparatus disclosed in Patent Document 2 can accurately detect the presence of a defect by illuminating light from two different directions, even if the defect has directionality. However, it takes a long time to acquire the entire defect of the imaging target that measures the defect while discovering the defect. Furthermore, the apparatus disclosed in Patent Document 3 is an apparatus that images a pattern with two different light receiving elements and compares the imaging results. Similarly, it is possible to accurately detect the presence of a defect, but in order to judge the entire object to be imaged, the time must be similarly increased.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a defect detection apparatus capable of accurately measuring and determining defects in a short time.

An embodiment of the defect measuring apparatus according to the present invention is as follows.
A first imaging device having a first imaging system for imaging an imaging target;
A second imaging device having a second imaging system different from the first imaging system and imaging the object to be imaged;
A first acquisition process for acquiring a position of a defect of the imaging target based on an imaging result obtained by imaging the imaging target region of the imaging target by the first imaging device; and a height direction of the defect for which the position is acquired And a defect information acquisition device that executes a second acquisition process for acquiring the above information by the second imaging device.

  According to the above embodiment, since the position of the defect is acquired by the first imaging device, and information on the height direction of the defect is acquired by the second imaging device based on the imaging result, the position of the defect is acquired. And processing for acquiring information in the height direction of the defect are executed separately. That is, instead of measuring the defect height information every time a defect is detected on the imaged object, first search for all the defects and immediately measure the defect height information at the position of the found defect. As a result, the processing can be rapidly advanced as a whole.

  Defects can be measured and determined accurately in a short time.

It is a block diagram which shows the whole structure of the defect measuring apparatus 100 by this Embodiment. It is a perspective view which shows the outline of the whole defect measuring apparatus 100 by this Embodiment. It is a perspective view which shows the outline of the imaging system 200 and the illumination system 400 by this Embodiment. It is a block diagram which shows the electrical structure of the defect measuring apparatus 100 by this Embodiment. It is a flowchart which shows a defect inspection operation | movement process. It is a flowchart which shows an image acquisition process. It is a flowchart which shows a defect detection process. It is a flowchart which shows a microscope height measurement process. 3 is a plan view showing an upper surface of a mold D. FIG. It is a figure which shows the kind of defect which can light and detect each of the 1st light source 400A-the 4th light source 400D. It is a table which shows the X coordinate and Y coordinate of the defect extracted about each of the 1st light source 400A-the 4th light source 400D. It is a figure which shows all the defects detected by illuminating 1st light source 400A-4th light source 400D on a map form. It is a table which shows the result of having processed about the detected defect.

  Embodiments will be described below with reference to the drawings.

According to a first embodiment of the invention,
A first imaging device (e.g., a line sensor camera 210 described later) having a first imaging system that images the imaging target;
A second imaging device (e.g., a confocal microscope 250 described later) having a second imaging system different from the first imaging system and imaging the object to be imaged;
First acquisition processing (for example, defect detection processing of FIG. 7 to be described later) that acquires the position of the defect of the imaging target based on the imaging result of imaging the imaging target area of the imaging target by the first imaging device And a second acquisition process (for example, a microscope height measurement process in FIG. 8 described later) for acquiring information on the height direction of the defect whose position has been acquired by the second imaging device. There is provided a defect measurement device including an information acquisition device (for example, a control system 100A and a microscope system 100B described later).

  The defect measurement device includes a first imaging device, a second imaging device, and a defect information acquisition device. The first imaging device has a first imaging system. The first imaging system images the imaging target.

  The second imaging device has a second imaging system. The second imaging system is different from the first imaging system. The second imaging system images the imaging target.

  The defect information acquisition device executes a first acquisition process and a second acquisition process. The first acquisition process is a process for acquiring the position of the defect of the imaging target. That is, in the first acquisition process, only the process of acquiring the position of the defect of the imaging target is performed without executing the process of acquiring the information in the height direction of the defect. In the first acquisition process, an imaging result captured by the first imaging device is used.

  In the second acquisition process, information on the height direction of the defect is acquired using the second imaging device. In the second acquisition process, information on the height direction of the defect is acquired using the position of the defect obtained in the first acquisition process. For example, the second imaging device is positioned at the position of the defect acquired in the first acquisition process. The information in the height direction includes, in addition to the height and depth, the tendency and degree of the spread of peaks (convex defects) and valleys (concave defects). In the second acquisition process, information on the height direction of the defect is acquired using the result of the first acquisition process called the position of the defect.

  In this way, the first acquisition process and the second acquisition process are executed separately. The processing result of the first acquisition process can be determined, and the processing result of the second acquisition process can be determined separately from the determination in the first acquisition process.

  If an unacceptable result is obtained at the stage of the first acquisition process, the process can be stopped at a time before starting the second acquisition process. Further, when an unacceptable result is obtained at the stage of the second acquisition process, the process can be stopped at a stage before the end of the second acquisition process. In this way, the timing at which the processing can be stopped can be increased, and if an unacceptable result occurs, the processing is immediately stopped to finish the processing at an early stage and start processing the next object to be imaged. be able to.

  In addition, it is preferable that the imaging resolution of the first imaging device is different from the imaging resolution of the second imaging device. For example, by reducing the resolution of the first imaging device and increasing the resolution of the second imaging device, it is possible to speed up the first acquisition process and increase the accuracy of the second acquisition process. Since the first acquisition process can be speeded up, it is possible to determine whether or not to stop the process at an early stage. Further, the processing can be optimized by setting the resolution necessary for each processing.

According to a second embodiment of the present invention, in the first embodiment of the present invention,
A plurality of light sources for illuminating the object to be imaged;
The first acquisition process includes:
Illumination imaging processing for illuminating the object to be imaged by separately lighting the plurality of light sources and imaging the imaging target region;
And defect position acquisition processing for acquiring the position of the defect of the imaging target based on the imaging result separately captured in the lighting imaging processing.

  It further includes a plurality of light sources for illuminating the object to be imaged. The first acquisition process includes a lighting imaging process and a defect position acquisition process.

  The lighting imaging process is a process in which a plurality of light sources are individually turned on and an imaging target region is imaged for each of the light sources that are turned on. Since the imaging target area is imaged for each light source, it is possible to capture an image by irradiating the imaging object with light suitable for the type of defect. The types of defects include concave defects and dents in addition to convex defects and streaky defects.

  In the defect position acquisition process, the position of the defect of the imaging target is acquired on the basis of the imaging results obtained separately. Since the position of the defect is acquired based on the imaging result obtained separately, the type of defect corresponding to the light source can be accurately detected.

A third embodiment of the present invention is the second embodiment of the present invention,
The defect information acquisition apparatus counts the number of defects for each type based on the imaging result acquired in the first acquisition process, and on the condition that the number of counted defects is determined to be greater than a predetermined number, The process is stopped without executing the second acquisition process.

  If the number of defects is larger than the predetermined number in the first acquisition process, the process is stopped at a point before starting the second acquisition process. If it is determined that it is not acceptable, the process can be completed without executing the second acquisition process.

According to a fourth embodiment of the present invention, in the first embodiment of the present invention,
The first imaging device has a line sensor camera, images at least a part of the imaging target region with the line sensor camera,
The second imaging device includes a confocal microscope and a microscope moving device that moves the confocal microscope so that a distance from the imaging target can be changed, and the confocal microscope is moved by the microscope moving device. Move to get information on the height direction of the defect.

  Since the first imaging device images at least a part of the imaging target area with the line sensor camera, the processing can be speeded up. The first imaging device only needs to capture at least a part of the imaging target region, and may capture the entire imaging target region at a time. Moreover, since the information of the height direction of a defect is acquired with a confocal microscope, the information of a height direction can be acquired correctly.

A fifth embodiment of the present invention is the fourth embodiment of the present invention,
The second imaging device stops the second acquisition process on condition that the information in the height direction of the defect exceeds a predetermined size.

  Even if there is an unacceptable defect after starting the second acquisition process, the second acquisition process is immediately stopped, so that the process can be completed early.

<<< Defect Measuring Apparatus 100 >>>

  FIG. 1 is a block diagram showing the overall configuration of the defect measuring apparatus 100. FIG. 2 is a perspective view showing the entirety of the defect measuring apparatus 100. FIG. 3 is an enlarged perspective view in which the drive system 300 and the illumination system 400 are enlarged. FIG. 4 is a block diagram showing an electrical configuration of the defect measuring apparatus 100. FIG. 5 is a flowchart showing the defect inspection operation process. FIG. 6 is a flowchart showing image acquisition processing. FIG. 7 is a flowchart showing the defect detection process. FIG. 8 is a flowchart showing the microscope height measurement process. FIG. 9 is a plan view showing the upper surface of the mold D. FIG.

  The defect measuring apparatus 100 is an apparatus that images an object to be imaged T, for example, a mold D (see FIG. 9), detects defects existing on the surface of the object to be imaged T, and measures the size and shape of the defect. In particular, the defect measuring apparatus 100 is an apparatus that measures the height of a convex defect present in the mold D.

  As shown in FIG. 1, the defect measuring apparatus 100 mainly includes an imaging system 200, a drive system 300, and an illumination system 400. The imaging system 200 mainly includes a line sensor camera 210 and a confocal microscope 250. The drive system 300 mainly includes an X stage 310X, a Y stage 310Y, and a Z stage 310Z. The illumination system 400 mainly includes a first light source 400A, a second light source 400B, a third light source 400C, and a fourth light source 400D.

  The drive system 300 moves and positions both the mold D and the imaging system 200 to a predetermined position. The illumination system 400 illuminates the surface of the mold D, and the imaging system 200 images the surface of the mold D.

  The first light source 400A to the fourth light source 400D are light sources used when the line sensor camera 210 images the mold D. When the confocal microscope 250 images the mold D, another halogen light source ( (Not shown) is used.

<< Imaging System 200 >>
As shown in FIG. 1, the imaging system 200 includes a line sensor camera 210 and a confocal microscope 250. The line sensor camera 210 scans the entire mold D (the entire upper surface) to detect and store the positions of defects present in the mold D. The confocal microscope 250 measures the height of each defect detected by the line sensor camera 210. As described above, the defect measuring apparatus 100 is equipped with an imaging apparatus having two different functions, that is, the line sensor camera 210 and the confocal microscope 250. The line sensor camera 210 is controlled by the control system 100A. The confocal microscope 250 is controlled by the microscope system 100B.

  As shown in FIG. 2, both the line sensor camera 210 and the confocal microscope 250 are mounted on the Y stage 310Y and the Z stage 310Z. Thus, when the Y stage 310Y is moved, the line sensor camera 210 and the confocal microscope 250 move together, and when the Z stage 310Z is moved, the line sensor camera 210 and the confocal microscope 250 move together. .

  The line sensor camera 210 and the Z stage 310Z may be mounted on the Y stage 310Y, and only the confocal microscope 250 may be mounted on the Z stage 310Z. In this case, the line sensor camera 210 and the confocal microscope 250 can be moved together by the Y stage 310Y. Only the confocal microscope 250 is moved by the Z stage 310Z.

<Line sensor camera 210>
The line sensor camera 210 has a predetermined number of pixels, for example, a 7000 pixel × 1 pixel CCD linear image sensor (not shown). One pixel of the CCD linear image sensor has a size of about 5 μm × about 5 μm. As shown in FIG. 9, the surface of the mold D in a range determined by the imaging area S can be imaged by the line sensor camera 210. The imaging area S corresponds to the size and shape of the CCD linear image sensor of the line sensor camera 210. A length ΔY in the longitudinal direction of the imaging area S is an actual length corresponding to 7000 pixels of the CCD linear image sensor. The length ΔX in the short direction of the imaging area S is the actual length corresponding to one pixel of the CCD linear image sensor.

  As shown in FIG. 2, the line sensor camera 210 is provided with an objective lens 212. By determining the magnification of the objective lens 212 according to the resolution required for imaging, ΔX and ΔY of the imaging area S can be determined according to the magnification of the objective lens 212. The resolution may be appropriately determined depending on the size, type, processing speed, etc. of the defect. As described above, the imaging area S has a size and shape corresponding to the shape and size of the CCD linear image sensor and the magnification of the objective lens 212.

  FIG. 9 is a plan view showing the upper surface of the mold D. FIG. In the present embodiment, the upper surface of the mold D has a quadrangular shape as shown in FIG. In FIG. 9, the downward direction on the paper is the + X direction, the upward direction is the -X direction, the right direction is the + Y direction, and the left direction is the -Y direction. As shown in FIG. 9, a reference mark M is formed on the mold D. The reference mark M is a mark for indicating a reference position and a reference angle of the mold D. By imaging the reference mark M together, the position and angle of the imaging data can be made uniform.

  As shown in FIG. 2, the mold D is placed on the X stage 310 </ b> X. In order to prevent the mold D from moving on the X stage 310X due to vibration or impact, it is preferable to place the mold D on the X stage 310X with a holding device (not shown), for example, with a magnet or the like. Any holding device may be used as long as the mold D can be locked to the X stage 310X.

  The mold D can be moved in the X direction by moving the X stage 310X. Further, by moving the Y stage 310Y, the imaging system 200 (line sensor camera 210 and confocal microscope 250) can be moved in the Y direction. The desired position of the mold D can be imaged by moving the X stage 310X and the Y stage 310Y.

  Imaging of the mold D by the line sensor camera 210 is performed according to the following procedure. First, the X stage 310X and the Y stage 310Y are moved to position the line sensor camera 210 above the upper end UT (see FIG. 9) of the area A1. Further, the Z stage 310Z is moved to position the line sensor camera 210 at a position where the surface of the mold D is in focus.

  The surface of the mold D in the range (ΔX × ΔY) determined by the imaging area S is imaged by one imaging process of the line sensor camera 210. Image data captured by the line sensor camera 210 is stored in the RAM 356 (see FIG. 4) of the control device 350.

  When one imaging process is completed, the X stage 310X is moved by ΔX in the −X direction, and the mold D is moved by ΔX. By moving the mold D by ΔX, the surface of the mold D in the imaging area S (ΔX × ΔY) adjacent in the + X direction can be imaged by the line sensor camera 210.

  For example, the X stage drive motor 314X (see FIG. 4) of the X stage 310X is provided with an encoder (not shown). An encoder signal indicating the position of the X stage drive motor 314X is output from the encoder. Based on the received encoder signal, the imaging process of the imaging area S by the line sensor camera 210 is executed. When the imaging process of the line sensor camera 210 is completed, a control signal for moving the X stage 310X is output to the X stage controller 312X (see FIG. 4). By repeating this operation, the entire area A1 shown in FIG.

  Imaging is terminated on the condition that the X stage 310X has been moved to the lower end DT of the mold D in the + X direction (downward in FIG. 9). Thereby, the whole long-shaped area | region A1 of the metal mold | die D can be imaged and memorize | stored.

  Next, the imaging system 200 (the line sensor camera 210 and the confocal microscope 250) is moved by ΔY in the + Y direction by the Y stage 310Y, and the line sensor camera 210 is located above the upper end portion UT of the area A2 on the right side of the area A1. Position. By imaging the mold D in the same manner as in the area A1, the entire area A2 can be imaged and stored.

  When the imaging system 200 is moved to the right adjacent region, it is preferable to position the two adjacent regions so as to overlap each other. For example, it is preferable to position the edge of the area A1 and the edge of the area A2 so that they slightly overlap. Specifically, all of the left side edge of the area A2 is always captured in the imaging data when the area A1 is imaged, and the right side edge of the area A1 is captured in the imaging data when the area A2 is imaged. Are always imaged, and the right side edge of the region A1 and the left side edge of the region A2 are imaged in an overlapping manner. By doing in this way, it can prevent that the blank area | region which is not imaged arises, and the whole surface of the metal mold | die D can always be imaged.

  By repeating the above-described processing, the area A1 → A2 →... → A6 → A7 of the mold D can be imaged one after another, and the entire surface of the mold D can be imaged. By imaging the entire surface of the mold D, it can be determined whether or not the mold D has a defect. If a defect exists, the position (X, Y) of the defect is stored. Details of specific processing will be described later.

  In the above-described processing, the upper end UT to the lower end DT of the region A1 is imaged, and then the upper end UT to the lower end DT of the adjacent region A2 is always imaged in one direction from the upper end UT. The case of starting imaging is shown. In addition, after imaging from the upper end UT to the lower end DT of the area A1, the imaging is performed bidirectionally (while reciprocating) so as to image from the lower end DT to the upper end UT of the adjacent area A2. It may be. It is possible to shorten the processing time by reducing the stage moving time.

<Confocal microscope 250>
The confocal microscope 250 irradiates the imaging target with illumination light emitted from a point light source so that information on the focal position passes through the pinhole and reaches the detector, and light other than the focal position is transmitted through the pinhole. It is a microscope that can be cut to generate a resolution in the depth direction to obtain an optical tomographic image. The confocal microscope 250 acquires only the image information of the focused portion on the imaging target, and can obtain a high-resolution and high-contrast image without being affected by unnecessary scattered light.

  As shown in FIG. 2, the confocal microscope 250 has an objective lens 254. The objective lens 254 includes two types of lenses, a 20 × objective lens and a 100 × objective lens. First, using a 20 × objective lens, adjustment (coarse adjustment) is performed so that the defect is positioned in the center of the imaging region, and then switching to a 100 × objective lens is performed to enlarge the defect and image the confocal microscope. Adjustment (fine adjustment) is performed so that the defect is located in the center of the imaging region 250.

  As will be described later, a confocal microscope 250 is mounted on the Z stage 310Z via a piezo element 330. The confocal microscope 250 can be finely moved in the ± Z direction (vertical direction) by the piezo element 330. By focusing on the defect and finely moving the confocal microscope 250, the focused position is gradually changed. The lowest position where the defect is in focus and the highest position where the defect is in focus can be detected, the position of the piezo element 330 corresponding to the lowest position of the defect, and the position of the piezo element 330 corresponding to the highest position of the defect. The height of the defect can be measured on the basis of the difference.

  The confocal microscope 250 is provided with a CCD camera 340 that is an area camera, and an image of a defect can be captured by the CCD camera 340.

<< Drive system 300 >>
As shown in FIG. 1, the drive system 300 includes a drive system 300A of the control system 100A and a drive system 300B of the microscope system 100B. The control system 100A and the microscope system 100B are communicably connected to each other via a communication line (not shown).

<Drive system 300A>
As shown in FIG. 1, the drive system 300A of the control system 100A mainly includes a control device 350, an X stage controller 312X, a Y stage controller 312Y, a Z stage controller 312Z, an X stage drive motor 314X, A stage drive motor 314Y and a Z stage drive motor 314Z are provided.

  As shown in FIG. 4, the control device 350 mainly includes a CPU 352, a ROM 354, a RAM 356, and an I / F (interface) 358. The CPU 352, ROM 354, RAM 356, and I / F 358 are connected by an address bus or a data bus (not shown). The CPU 352, the ROM 354, and the RAM 356 execute programs according to flowcharts shown in FIGS. These programs are stored in the ROM 354 in advance.

  An X stage controller 312X, a Y stage controller 312Y, and a Z stage controller 312Z are connected to the I / F 358. The X stage controller 312X, the Y stage controller 312Y, and the Z stage controller 312Z include a motor driver, generate drive signals from the control signals output from the CPU 352, and generate an X stage drive motor 314X and a Y stage drive motor 314Y. And a drive signal is transmitted to the Z stage drive motor 314Z. The X stage drive motor 314X, the Y stage drive motor 314Y, and the Z stage drive motor 314Z are driven with a rotation direction or a rotation speed according to a drive signal.

  The X stage 310X, the Y stage 310Y, and the Z stage 310Z are so-called linear stages, and it is sufficient that the table placed on the guide rail so as to be movable can be linearly moved. The driving method of the X stage 310X, the Y stage 310Y, and the Z stage 310Z may be air driving, in addition to driving by a linear motor, driving by a rotary motor and a ball screw. In any case, it is sufficient that the table can be moved along the guide rail. A rotatable rotary stage may be included depending on the object to be measured.

  By driving the X stage drive motor 314X, the X stage 310X can be moved in the + X direction or the -X direction at a predetermined speed. The mold D is placed on the X stage 310X, and the mold D can be moved by moving the X stage 310X.

  By driving the Y stage drive motor 314Y, the Y stage 310Y can be moved in the + Y direction or the −Y direction at a predetermined speed. The Z stage 310Z is mounted on the Y stage 310Y, and the Z stage 310Z can be positioned at a desired position.

  By driving the Z stage drive motor 314Z, the Z stage 310Z can be moved in the + Z direction or the −Z direction at a predetermined speed. A line sensor camera 210 and a confocal microscope 250 are mounted on the Z stage 310Z, and each of the line sensor camera 210 and the confocal microscope 250 can be positioned at a desired position by moving the Z stage 310Z. .

<Drive system 300B>
As shown in FIG. 1, the drive system 300B of the microscope system 100B mainly includes a control device 370, a piezo element 330, and an objective lens drive motor 320.

  As shown in FIG. 4, the control device 370 mainly includes a CPU 372, a ROM 374, a RAM 376, and an I / F (interface) 378. The CPU 372, the ROM 374, the RAM 376, and the I / F 378 are connected by an address bus or a data bus (not shown). The CPU 372, the ROM 374, and the RAM 376 execute a program according to a flowchart shown in FIG. The program is stored in the ROM 374 in advance.

  A CCD camera 340 connected to the piezo element 330, the objective lens driving motor 320, and the confocal microscope 250 is connected to the I / F 378.

  The piezo element 330 is driven by a control signal output from the CPU 372. A confocal microscope 250 is mounted on the Z stage 310 </ b> Z via a piezo element 330. By driving the piezo element 330, the confocal microscope 250 is moved in the vertical direction (± Z direction) on the Z stage 310Z. By moving the confocal microscope 250 downward (−Z direction), the confocal microscope 250 approaches the mold D placed on the X stage. When the confocal microscope 250 moves upward (+ Z direction), the confocal microscope 250 moves away from the mold D placed on the X stage.

  By moving the X stage 310X, the Y stage 310Y, and the Z stage 310Z, the X, Y, and Z positions of the confocal microscope 250 can be coarsely and finely adjusted. The coarse adjustment and fine adjustment will be described in detail later. By driving the piezo element 330, the height of the defect can be measured by finely moving the confocal microscope 250 to a position in the Z direction.

  By driving the piezo element 330, the confocal microscope 250 is finely moved to gradually change the position where the defect and the focal point are in focus. By finely moving the confocal microscope 250, it is possible to determine the lowest position and the highest position where the defect is in focus. The height of the defect can be determined based on the difference between the position of the piezo element 330 corresponding to the lowest position of the defect and the position of the piezo element 330 corresponding to the uppermost position of the defect.

  The objective lens drive motor 320 is driven by a control signal output from the CPU 372. The objective lens 254 is selected by driving the objective lens driving motor 320. The objective lens 254 includes a 20 × objective lens and a 100 × objective lens. One of the 20 × objective lens and the 100 × objective lens is selected by the control signal output from the CPU 372 and positioned in a state where the confocal microscope 250 can capture an image.

  In the state where the 20 × objective lens is selected, coarse adjustment of the positions of the X stage 310X, the Y stage 310Y, and the Z stage 310Z is performed. In the state where the 100 × objective lens is selected, the X stage 310X, the Y stage 310Y, and the Z stage 310Z are finely adjusted.

  By the coarse adjustment and fine adjustment of the X stage 310X and the Y stage 310Y, the defect is positioned at the center of the imaging region of the confocal microscope 250. Furthermore, the confocal microscope 250 is positioned in a range where the defect can be focused by rough adjustment and fine adjustment of the Z stage 310Z.

  A CCD camera 340 that is an area camera is provided in the confocal microscope 250 and outputs a focus signal and an imaging signal. A focus signal and an imaging signal output from the CCD camera 340 are input to the control device 370 via the I / F 378. The control device 370 outputs a control signal based on the input focus signal and drives the piezo element 330. Further, the control device 370 generates imaging data obtained by imaging the mold D based on the input imaging signal, and stores the imaging data in the RAM 376.

<< Lighting system 400 >>
As shown in FIG. 1, the illumination system 400 includes a first illumination system, a second illumination system, a third illumination system, and a fourth illumination system. These first to fourth illumination systems are used when the line sensor camera 210 images the surface of the mold D.

  The first illumination system includes a first light source 400A and a first light guide 410A. The first light guide 410A is a straight light guide. The first illumination system is mainly an illumination system for detecting convex defects.

  The second illumination system includes a second light source 400B and a second light guide 410B. The second light guide 410B is a straight light guide. The third illumination system includes a third light source 400C and a third light guide 410C. The fourth illumination system includes a fourth light source 400D and a fourth light guide 410D. The third light guide 410C and the fourth light guide 410D are line type light guides. The second to fourth illumination systems are mainly illumination systems for detecting streak-like defects and defects spreading in the upper surface of the mold D. For example, defects having anisotropy can be detected by the second to fourth illumination systems.

  The first light source 400A to the fourth light source 400D are made of, for example, a metal halide lamp. Each of the first light source 400A to the fourth light source 400D is formed with an emission part (not shown) that emits light. An incident surface (not shown) of the first light guide 410A is connected to the emission portion of the first light source 400A. An incident surface (not shown) of the second light guide 410B is connected to the emission portion of the second light source 400B. An incident surface (not shown) of the third light guide 410C is connected to the emission portion of the third light source 400C. An incident surface (not shown) of the fourth light guide 410D is connected to the emission portion of the fourth light source 400D.

  As shown in FIG. 3, the exit surface 412A of the first light guide 410A, the exit surface 412B of the second light guide 410B, the exit surface 412C of the third light guide 410C, and the exit surface 412D of the fourth light guide 410D. Are arranged toward the X stage 310X (die D). FIG. 3 shows only the vicinity of the emission surface 412D of the first light guide 410A to the emission surface 412D of the fourth light guide 410D, and is connected to the emission surface 412D of the first light guide 410A to the fourth light guide 410D. The optical fiber that has been shown is omitted.

  The light emitted from the first light source 400A is guided by the first light guide 410A and emitted from the emission surface 412A to illuminate the mold D. The light emitted from the second light source 400B is guided by the second light guide 410B and emitted from the emission surface 412B to illuminate the mold D. The light emitted from the third light source 400C is guided by the third light guide 410C and emitted from the emission surface 412C to illuminate the mold D. The light emitted from the fourth light source 400D is guided by the fourth light guide 410D and emitted from the emission surface 412D to illuminate the mold D.

  As described above, the first light guide 410A and the second light guide 410B are straight light guides, and the emission surface is formed in a substantially circular shape to illuminate a substantially circular region. The third light guide 410C and the fourth light guide 410D are line type light guides, and the emission surface is formed in a long rectangular shape, and emits slit light to illuminate a substantially rectangular region.

  The illumination conditions such as the direction in which the mold D is illuminated and the shape and size of the region are assigned to each of the first light guide 410A to the fourth light guide 410D according to the type, size, and shape of the defect. Further, illumination conditions such as the wavelength and intensity of light can be assigned to each of the first light source 400A to the fourth light source 400D according to the type, size, and shape of the defect. As described above, the defects include a convex defect, a streak-like defect, a defect spreading in the upper surface of the mold D, and a concave defect or a dent. The illumination conditions that can be determined by the first light source 400A to the fourth light source 400D and the first light guide 410A to the fourth light guide 410D may be determined according to the type, size, and shape of the defect. Various defects can be detected by sequentially switching the first light source 400A to the fourth light source 400D, illuminating the mold D, and imaging the mold D.

  The number of light sources, the wavelength of light, the shape of the light guide exit surface, and the like may be appropriately determined according to the type, size, and shape of the defect to be detected.

<<< Control processing >>>
In the following, it is assumed that the startup process such as initialization of the defect measuring apparatus 100 is completed, and the defect measuring apparatus 100 is operating in a steady state. Position information indicating the home position of the X stage 310X, the Y stage 310Y, and the Z stage 310Z is stored in advance in the ROM 354, the RAM 356, and the like. Further, position information (offset information and the like) of the line sensor camera 210 and the confocal microscope 250 on the Y stage 310Y is also stored in advance in the ROM 354, the RAM 356, and the like. For example, the offset information is information indicating a relative positional relationship between the center of the line sensor camera 210 and the center of the CCD camera 340 of the confocal microscope 250.

  FIG. 5 is a flowchart showing the defect inspection operation process. FIG. 6 is a flowchart showing image acquisition processing. FIG. 7 is a flowchart showing the defect detection process. FIG. 8 is a flowchart showing the microscope height measurement process.

  5 to 7 are executed by the control device 350. By this processing, the line sensor camera 210 detects defects on the entire surface of the mold D, and the positions of all detected defects are stored in the RAM 356. FIG. 8 is executed by the control device 370. By this processing, the confocal microscope 250 is positioned at the position stored in the RAM 356, and the height of the defect is measured.

  As described above, the line sensor camera 210 and the confocal microscope 250 are separate imaging devices having different functions. 5 to 7 is processing for detecting the defects of the mold D by the line sensor camera 210 and storing the positions of all the defects. The process of FIG. 8 is a process of measuring the height of the defect with the confocal microscope 250 using the results of the processes of FIGS. Thus, the process using the confocal microscope 250 (FIG. 8) is a process (FIGS. 5 to 7) subordinate to the process using the line sensor camera 210.

<< Defect inspection operation process >>
First, the image acquisition process of FIG. 6 is called, the first light source 400A is turned on to illuminate the mold D, and an image is acquired and a defect is detected (step S411). By turning on the first light source 400A, a convex defect can be mainly detected. By turning on the first light source 400A, for example, a convex defect as shown in FIG. 10A can be detected. The example shown in FIG. 10A shows that five convex defects exist on the upper surface of the mold D.

  Next, it is determined whether or not the number of defects detected in the process of step S411 is within an allowable range (step S413). This allowable range is a condition for determining the number of types of defects that can be detected by the first light source 400A. If it is determined in step S413 that the allowable range is not exceeded, it is determined that the mold is appropriate D, and if the allowable range is exceeded, it is determined that the mold D is inappropriate.

  If it is determined in step S413 that the number of defects is within the allowable range, the image acquisition process of FIG. 6 is called, the second light source 400B is turned on to illuminate the mold D, and an image is acquired. Then, a process for detecting a defect is executed (step S415). By turning on the second light source 400B, it is possible to mainly detect streak-like defects. By turning on the second light source 400B, for example, a streak-like defect extending in the vertical direction (± X direction) as shown in FIG. 10B can be detected. In the example shown in FIG. 10B, one streak-like defect extending in the vertical direction (± X direction) is present near the left end portion LT (see FIG. 9) on the upper surface of the mold D.

  Next, it is determined whether or not the number and size of defects detected in the process of step S415 are within an allowable range (step S417). This allowable range is a condition for determining the number and size of types of defects that can be detected by the second light source 400B. The size is a length or an area. If it is determined in step S417 that the allowable range is not exceeded, it is determined as an appropriate mold D. If the allowable range is exceeded, it is determined as an inappropriate mold D.

  When it is determined in the determination process in step S417 that the number and size of defects are within the allowable range, the image acquisition process in FIG. 6 is called, the third light source 400C is turned on to illuminate the mold D, and the image Is acquired to detect a defect (step S419). By turning on the third light source 400C, it is possible to mainly detect the spread defects. By turning on the third light source 400C, for example, a defect spreading in the upper surface (XY plane) of the mold D as shown in FIG. 10C can be detected. In the example shown in FIG. 10C, it is shown that a defect extending in the upper surface (XY plane) of the mold D exists in the lower left region of the upper surface of the mold D.

  Next, it is determined whether or not the number and size of defects detected in the process of step S419 are within an allowable range (step S421). This allowable range is a condition for determining the number and size of types of defects that can be detected by the third light source 400C. The size is a length or an area. If it is determined in step S421 that the allowable range is not exceeded, it is determined that the mold is appropriate D, and if the allowable range is exceeded, it is determined that the mold D is inappropriate.

  When it is determined in the determination process in step S421 that the number and size of defects are within the allowable range, the image acquisition process in FIG. 6 is called, the fourth light source 400D is turned on to illuminate the mold D, and the image And processing for detecting a defect is executed (step S423). By turning on the fourth light source 400D, it is possible to mainly detect streak-like defects. By turning on the fourth light source 400D, for example, a streak-like defect extending in the horizontal direction (± Y direction) as shown in FIG. 10D can be detected. In the example shown in FIG. 10D, it is shown that there is one streak-like defect extending in the lateral direction (± Y direction) near the upper end UT of the mold D.

  Next, it is determined whether or not the number and size of defects detected in the process of step S421 are within an allowable range (step S425). This allowable range is a condition for determining the number and size of types of defects that can be detected by the fourth light source 400D. The size is a length or an area. If it is determined in step S425 that the allowable range is not exceeded, it is determined as an appropriate mold D, and if the allowable range is exceeded, it is determined as an inappropriate mold D.

  The permissible ranges of the above-described steps S413, S417, S421, and S425 may be determined according to the type and size of the defect that can be detected by illuminating the light emitted from the first light source 400A to the fourth light source 400D. Good.

  When it is determined that the number of defects exceeds the allowable range in the determination process of step S413 described above, or when it is determined that the number and size of the defects exceed the allowable range in the determination process of step S417, S421, or S425 In this case, the subroutine is immediately terminated and the defect inspection is stopped. By doing so, when the number of defects is too large or the size of the defect is large, the process is interrupted at a time point before executing the process of the confocal microscope 250 of FIG. The overall processing time can be shortened. That is, when the number of defects is too large or the size of the defect is large, it is an inappropriate mold D without measuring the height of the defect, and the height of the defect is measured with the confocal microscope 250. Without interrupting the process, the entire processing time can be shortened.

  Next, a subroutine for defect detection processing shown in FIG. 7 is called to generate combined data obtained by combining data captured by the first light source 400A to the fourth light source 400D, and the position of the defect is acquired from the combined data ( Step S426). Details of the defect detection process will be described later.

  Next, the defect position data acquired in step S426 is read from the RAM 356, and the X stage 310X and Y stage 310Y are moved based on the position data to position the confocal microscope 250 at the position of the defect (step S427). ).

  Next, the microscope height measurement process shown in FIG. 8 is called and executed to measure the height of the defect (step S429). Details of the microscope height measurement process will be described later.

  Next, it is determined whether or not the height of the defect is within an allowable range (step S431).

  When it is determined that the defect height is within the allowable range, it is determined whether or not all the defect heights have been measured (step S433). If it is determined that the heights of all the defects have not been measured, the process returns to step S427.

  When it is determined that the heights of all the defects have been measured, the positions and types of all the defects are displayed in a map on the display (not shown) of the control device 350 (step S435), and this subroutine is terminated. . The position and type of defects present in the mold can be displayed on the display.

  For example, as shown in FIG. 12, the defect detected by illuminating the first light source 400A to the fourth light source 400D can be displayed on the display. FIG. 12 is a diagram illustrating a state of the entire upper surface of the mold D, and the squares indicate the outline of the mold D. In the example shown in FIG. 12, all of the defects shown in each of FIGS. 10A to 10D are superimposed and displayed. By displaying in this way, the type, position, size, direction, and the like of defects present on the upper surface of the mold D can be displayed in a map form so as to be visible. In addition, it is preferable to display a defect on a display by changing a color according to the kind of defect. The type, position, size and direction of the defect can be clearly seen.

<< Image acquisition process >>
FIG. 6 is a flowchart showing image acquisition processing. This process is a process for detecting the defect by imaging the mold D by the line sensor camera 210 and specifying the position of the detected defect. This process is a subroutine that is called and executed in steps S411, S415, S419, and S423 in FIG.

  First, a light source to be lit is designated (step S511). In this embodiment, any one of the first light source 400A to the fourth light source 400D is designated. When this subroutine is called in the process of step S411, the first light source 400A is designated. When this subroutine is called in the process of step S415, the second light source 400B is designated. When this subroutine is called in the process of step S419, the third light source 400C is designated. When this subroutine is called in the process of step S423, the fourth light source 400D is designated. It can be determined according to the number of light sources used for illumination.

  Next, the light source designated in step S511 is turned on (step S513). With this process, the mold D is illuminated in an area corresponding to the light source that is lit.

  When the first light source 400A is turned on, light is emitted from the emission surface of the first light guide 410A to illuminate the substantially circular region of the mold D. When the second light source 400B is turned on, light is emitted from the emission surface of the second light guide 410B to illuminate a substantially circular area of the mold D. When the third light source 400C is turned on, light is emitted from the emission surface of the third light guide 410C to illuminate a substantially rectangular area of the mold D. When the fourth light source 400D is turned on, light is emitted from the emission surface of the fourth light guide 410D to illuminate a substantially rectangular region of the mold D.

  Next, the line sensor camera 210 is positioned at the imaging position by the Y stage 310Y (step S515). Specifically, first, the line sensor camera 210 is positioned above the upper end portion UT of the area A1.

  The process of step S515 is a process of positioning the line sensor camera 210 at the image acquisition start position. The image acquisition start position is a position at which the line sensor camera 210 starts image acquisition (imaging). In the example described above, the upper end UT is set as the image acquisition start position. The image acquisition start position may be a position where the entire upper surface of the mold D can be imaged with the line sensor camera 210.

  The mold D is assumed to have various sizes and shapes. For this reason, it is preferable to appropriately set the image acquisition start position according to the size and shape of the mold D. For example, it is preferable that the image acquisition start position is manually input by the user and stored in advance. By configuring so that the image acquisition start position can be read according to the size and shape of the mold D, the operation can be simplified.

  Next, the imaging area S is imaged by the line sensor camera 210, and the imaging data is stored in the RAM 356 (step S517). Next, the X stage 310X is moved by ΔX in the area A1, and the mold D placed on the X stage 310X is moved (step S519).

  Specifically, as described above, a signal indicating the position of the X stage drive motor 314X is output from the encoder. When this signal is received, the imaging process of the imaging area S by the line sensor camera 210 is executed. When the imaging process of the line sensor camera 210 is completed, a control signal for moving the X stage 310X is output to the X stage controller 312X. Such processing is executed in the processing of steps S517 and S519.

  Next, it is determined whether or not the X stage 310X has reached the lower end DT in the + X direction (step S521). If it is determined that the X stage 310X has not reached the lower end DT in the + direction, the process returns to step S517.

  When it is determined that the X stage 310X has reached the lower end portion DT in the + direction, the imaging of the line sensor camera 210 is terminated (step S523). In this way, the entire area A1 can be imaged.

  By repeatedly executing the processes of steps S517 to S521 described above, the entire surface of one region can be imaged.

  Next, it is determined whether or not the Y stage 310Y has reached the right end portion RT in the + Y direction (step S525). That is, it is determined whether or not the Y stage 310Y has reached A7. When it is determined that the Y stage 310Y has not reached the right end portion RT in the + Y direction, the process returns to step S515, and the line sensor camera 210 is moved by ΔY and positioned above the upper end portion UT. That is, the line sensor camera 210 is positioned above the upper end UT of the adjacent area.

  By repeatedly executing the processing of steps S515 to S525, the line sensor camera 210 can be positioned in the order of the areas A1, A2,..., A6, A7, and each area can be imaged.

  When it is determined that the Y stage 310Y has reached the right end portion RT in the + Y direction, this subroutine is terminated.

<Defect detection process>
FIG. 7 is a flowchart showing the defect detection process. This process is called and executed in step S426 of FIG. This process is a process for detecting a defect from the imaging data and acquiring position information of the defect.

  First, the reference mark M of the mold D is searched from the imaging data (step S527). At this time, for each of A1 to A7, there is imaging data illuminated with each of the first light source 400A to the fourth light source 400D, and there are a total of 7 × 4 imaging data. If all these imaging data are appropriately captured, the reference mark M indicating the reference position and reference angle of the mold D is captured.

  Next, it is determined whether or not the reference mark M of the mold D has been imaged for all the imaging data (step S529). If the imaging data in which the reference mark M of the mold D is not captured is included, this subroutine is immediately terminated. If the fiducial mark M of the mold D has not been imaged, the image data cannot be appropriately combined, so this subroutine is terminated.

  As described above, 7 × 4 pieces of imaging data are stored in the RAM 356. If it is determined in step S529 that the reference mark M of the mold D has been imaged for all the imaging data, these imaging data are read from the RAM 356 and the angle and position are corrected from the reference mark M. All the imaging data are combined to generate image data indicating the entire surface of the mold D (step S531).

  In the process of step S531, the angle and position of the image data are corrected so that the imaged reference mark M is aligned, and image data is generated by combining the image data. Each of the 7 × 4 pieces of imaging data may be imaged with the imaging start position shifted or tilted. For this reason, using the reference mark M being imaged, the angle and position of the imaging data are corrected and the imaging data are combined so that all the imaging data is gathered.

  As described above, there are four types of first light source 400A to fourth light source 400D, and imaging data is combined for each of the first light source 400A to fourth light source 400D. That is, seven image data obtained when the first light source 400A is illuminated is combined to generate a single image data (image_data_A), and seven image data obtained when the second light source 400B is illuminated is combined. A single image data (image_data_B) is generated, and the seven image data when the third light source 400C is illuminated is combined to generate a single image data (image_data_C), and the fourth light source 400D is illuminated. The seven image data at the time are combined to generate a single image data (image_data_C). In this manner, four image data (image_data_A to image_data_D) corresponding to each of the first light source 400A to the fourth light source 400D are generated.

  Note that an image as shown in FIG. 10A can be displayed by a single image data (image_data_A) when the first light source 400A is illuminated, and a single image when the second light source 400B is illuminated. An image as shown in FIG. 10B can be displayed by the data (image_data_B), and an image as shown in FIG. 10C is displayed by a single image data (image_data_C) when the third light source 400C is illuminated. The image as shown in FIG. 10D can be displayed by a single image data (image_data_D) when the fourth light source 400D is illuminated. 10A to 10D are diagrams illustrating the entire state of the upper surface of the mold D, and the squares indicate the outline of the mold D. FIG.

  The combined image data includes information on all types of imaged defects. As described above, the defect includes a convex defect, a stripe defect, and the like, and information on these types of defects is included in the image data.

  Next, a defect is detected from the combined image data (step S533). Defects can be detected by the location where the color (hue, saturation, brightness) of the image data changes, the size or shape of a range in which the color differs from the surroundings.

  Next, the position of the detected defect is stored (step S535). For example, the position of the center of gravity of the detected defect is calculated, and the position of the center of gravity is stored as a representative position of the defect. Here, the position of the defect may be in units of the number of pixels that can be acquired from the image data, or in units of the actual length.

  Next, it is determined from the combined image data whether or not the inspection of the entire surface of the mold D has been completed (step S537). If it is determined that the entire inspection of the mold D has not been completed, the process returns to step S533.

  If it is determined in step S537 that the inspection of the entire surface of the mold D has been completed, the four image data (image_data_A to image_data_D) corresponding to each of the first light source 400A to the fourth light source 400D are inspected. It is determined whether or not (step S539). If it is determined that all the image data (image_data_A to image_data_D) have not been inspected, the process returns to step S533. When it is determined that all image data (image_data_A to image_data_D) have been inspected, this subroutine is terminated.

  By this processing, defects existing on the entire surface of the mold D are extracted for each of the four image data (image_data_A to image_data_D) corresponding to each of the first light source 400A to the fourth light source 400D, and the extracted defect The position can be acquired. For example, as shown in FIG. 11, the X coordinate and Y coordinate of the defect extracted for each of the first light source 400 </ b> A to the fourth light source 400 </ b> D are stored in the RAM 356 of the control device 350.

<< Microscope height measurement process >>
FIG. 8 is a flowchart showing the microscope height measurement process. This process is a process for measuring information in the height direction of the defect, for example, the height of the defect, using the confocal microscope 250.

  When imaging the mold D with the confocal microscope 250, the mold D is illuminated through a half mirror with coaxial incident illumination light (not shown). For example, a halogen light source can be used as a light source for coaxial epi-illumination light. Further, the confocal microscope 250 is provided with a CCD camera 340 as an area camera so as to be able to take an image.

  First, the objective lens driving motor 320 of the confocal microscope 250 is driven to select a 20 × objective lens (step S611). At this point, the confocal microscope 250 functions as a normal microscope. An area that can be imaged by the CCD camera 340 (area camera) is determined by the 20 × objective lens. For example, an area of about 200 μm × 150 μm can be imaged. The magnification of the objective lens may be determined according to the size and shape of the target defect.

  Next, centering is performed by driving the X stage driving motor 314X and the Y stage driving motor 314Y to move the X stage 310X and the Y stage 310Y (step S613). Centering is a process of positioning one defect to be measured at the center of the imaging region of the CCD camera 340 of the confocal microscope 250.

  Next, the defect is focused (focusing) by driving the Z stage drive motor 314Z and moving the Z stage 310Z (step S615). In this process, the Z stage 310Z is moved based on the focus signal output from the CCD camera 340, thereby focusing on the defect. This focusing is a process of moving the Z stage 310Z so that the confocal microscope 250 is positioned in a range where the focus of the confocal microscope 250 matches the defect.

  As described above, the movement of the X stage 310X, the Y stage 310Y, and the Z stage 310Z is controlled by the drive system 300A of the control system 100A. In the processes in steps S613 and S615, a command for moving the X stage 310X, the Y stage 310Y, and the Z stage 310Z is transmitted from the microscope system 100B to the control system 100A, and the X stage 310X, the Y stage 310Y, and Z are transmitted by the drive system 300A. The stage 310Z is moved.

  Next, it is determined whether or not the operation is completed (step S617). This process is a determination as to whether or not centering and focusing have been completed. If it is determined that the operation has not been completed, the process returns to step S613.

  Next, when it is determined that the operation is completed, it is determined whether or not a defect exists (step S619). If it is determined that there is no defect, this subroutine is immediately terminated.

  The case where it is determined that there is no defect is a case where it is determined that there is no defect when it is imaged by the line sensor camera 210, but it is determined that there is no defect when centering and focusing are performed with a 20x objective lens. . For example, the line sensor camera 210 captures dust as a defect, but the dust moves after that and the 20 × objective lens cannot detect the dust.

  Coarse adjustment is performed by executing the processes of steps S611 to S619 described above.

  If it is determined in step S619 that there is a defect, the objective lens driving motor 320 of the confocal microscope 250 is driven to select a 100 × objective lens (step S621). At this point, the confocal microscope 250 functions as a normal microscope. By increasing the magnification, the defect can be enlarged and imaged.

  Next, centering is performed by driving the X stage drive motor 314X and the Y stage drive motor 314Y to move the X stage 310X and the Y stage 310Y (step S623). By imaging and centering a defect with a 100 × objective lens, one defect to be measured can be accurately positioned in the center of the imaging area of the CCD camera 340 of the confocal microscope 250.

  Next, the defect is focused (focusing) by driving the Z stage drive motor 314Z and moving the Z stage 310Z (step S625). This process is the same process as step S615. In this way, it is possible to always focus on the defect within a predetermined range in the Z direction.

  In the processes of steps S623 and S625 described above, a command for moving the X stage 310X, the Y stage 310Y, and the Z stage 310Z is transmitted from the microscope system 100B to the control system 100A and driven in the same manner as the processes of steps S613 and S615. The X stage 310X, the Y stage 310Y, and the Z stage 310Z are moved by the system 300A.

  Next, it is determined whether or not the operation is completed (step S627). If it is determined that the operation has not been completed, the process returns to step S623.

  When it is determined that the operation has been completed, it is determined again whether or not a defect exists (step S629). If it is determined that there is no defect, this subroutine is immediately terminated.

  The case where it is determined that there is no defect is determined to be a defect when centering and focusing is performed with a 20 × objective lens, but it is determined that there is no defect when centering and focusing is performed with a 100 × objective lens. This is the case. For example, there is a case where dust is imaged as a defect with a 20 × objective lens, but the dust moves after that and no dust is detected with a 100 × objective lens. Thus, by determining whether or not a defect exists until immediately before measuring the actual height of the defect, the height of the defect can be appropriately measured.

  Fine adjustment is performed by executing the processing of steps S621 to S629 described above.

  When it is determined that a defect exists, the confocal microscope 250 is caused to function as a confocal microscope, and the height is measured by driving the piezo element 330 to find a focused position (step S631). Exit.

  Specifically, the piezo element 330 is reciprocated while detecting the contrast of the captured image. For example, the piezo element 330 is gradually finely moved within a range of 100 μm. The lowest position in focus is the lowest position of the defect, and the highest position in focus is the highest position of the defect. The difference between the highest position and the lowest position is calculated as the defect height.

  Each time the measurement of the height of one defect is completed, an image indicating the appearance of the defect and data indicating the cross-sectional shape of the defect are transmitted from the microscope system 100B to the control system 100A. The control system 100A sequentially accumulates data regarding the height of the defect. By classifying types and trends of defects, it is possible to easily analyze the causes of defects.

<<<< Other >>>>
In the above-described example, the case where the confocal microscope 250 is used to measure the height of the defect is shown. However, any device that can obtain information on the height direction of the defect may be used. In addition to a device that measures using laser light, a device that measures with a stylus may be used. A device for measuring the height of the defect may be provided separately from the device for detecting the defect. An apparatus for measuring the height of a defect may be determined as appropriate according to the material to be measured, speed, and accuracy.

  In the above-described example, the case where the height of the defect is measured has been described. However, the defect height information may be acquired, for example, the depth of the defect may be measured.

  In the above example, the mold D has a quadrilateral shape, but other shapes, for example, objects such as irregular shapes in addition to polygons and circles are targeted. Can do. In any case, it is sufficient that the reference mark M is formed so as to be capable of imaging.

  In addition to the position and height of the defect, the area of the defect, and if the defect has an anisotropic shape, the length and direction of the defect, the inclination of the valley or mountain, etc. may be stored. Such defects are classified by information such as the position and height of the defect, the area and length and direction of the defect, and the inclination of the valley or mountain (for example, see FIG. 13), and the size, shape, direction and distribution of the defect. It is preferable to perform statistical processing such as the above and save the data. Statistical processing can facilitate the investigation of the cause of the defect.

  For example, when the imaging target T is a mold D, the child mold is duplicated from the parent mold, which is the prototype, and the grandchild mold is duplicated from the child mold, There is a case where a mold for a plurality of generations is generated. In this way, when there are multiple generations of molds, information such as the number and position of defects is saved for each generation, making it easy to verify and manage which generation caused the defect. can do.

  Further, by periodically inspecting the mold D and comparing past data registered in the database, it is possible to detect the change of the mold D with time and facilitate the management of the mold D.

DESCRIPTION OF SYMBOLS 100 Defect measuring apparatus 100A Control system 100B Microscope system 200 Imaging system 300 Drive system 400 Illumination system

An embodiment of the defect measuring apparatus according to the present invention is as follows.
A first imaging device having a first imaging system for imaging an imaging target;
A second imaging device having a second imaging system different from the first imaging system and imaging the object to be imaged;
A plurality of light sources for illuminating the object to be imaged;
A first acquisition process for acquiring a position of a defect of the imaging target based on an imaging result obtained by imaging the imaging target region of the imaging target by the first imaging device; and a height direction of the defect for which the position is acquired A defect information acquisition device that executes a second acquisition process for acquiring the information by the second imaging device ,
The first acquisition process includes:
A first illumination imaging process for illuminating the object to be imaged with one of the plurality of light sources and imaging the imaging target region;
A defect counting process for counting the number of defects based on the imaging result obtained in the first illumination imaging process;
On the condition that the number of defects is determined to be equal to or less than a predetermined number, the object to be imaged is illuminated with another light source different from the one light source among the plurality of light sources, and the imaging target region is imaged. Second illumination imaging processing to
And a stop process for stopping the process without executing the second acquisition process on the condition that the number of counted defects is determined to be larger than the predetermined number .

According to the above embodiment, since the position of the defect is acquired by the first imaging device, and information on the height direction of the defect is acquired by the second imaging device based on the imaging result, the position of the defect is acquired. And processing for acquiring information in the height direction of the defect are executed separately. That is, instead of measuring the defect height information every time a defect is detected on the imaged object, first search for all the defects and immediately measure the defect height information at the position of the found defect. As a result, the processing can be rapidly advanced as a whole. Further, on the condition that the number of defects is determined to be equal to or less than a predetermined number, the imaging target region is imaged by illuminating the imaging target with another light source different from the one light source. Defects can be accurately detected.

Claims (5)

A first imaging device having a first imaging system for imaging an imaging target;
A second imaging device having a second imaging system different from the first imaging system and imaging the object to be imaged;
A first acquisition process for acquiring a position of a defect of the imaging target based on an imaging result obtained by imaging the imaging target region of the imaging target by the first imaging device; and a height direction of the defect for which the position is acquired And a defect information acquisition device that executes a second acquisition process for acquiring the information by the second imaging device. A plurality of light sources for illuminating the object to be imaged;
The first acquisition process includes:
Illumination imaging processing for illuminating the object to be imaged by separately lighting the plurality of light sources and imaging the imaging target region;
The defect measurement apparatus according to claim 1, further comprising: a defect position acquisition process that acquires a position of a defect of the imaging target based on an imaging result separately captured in the lighting imaging process.   The defect information acquisition device counts the number of defects for each type based on the imaging result acquired in the first acquisition process, and on the condition that the number of counted defects is determined to be greater than a predetermined number, The defect measuring apparatus according to claim 2, wherein the process is stopped without executing the second acquisition process. The first imaging device has a line sensor camera, images at least a part of the imaging target region with the line sensor camera,
The second imaging device includes a confocal microscope and a microscope moving device that moves the confocal microscope so that a distance from the imaging target can be changed, and the confocal microscope is moved by the microscope moving device. The defect measuring apparatus according to claim 1, wherein the defect measuring apparatus moves to acquire information in a height direction of the defect.   The defect measurement apparatus according to claim 4, wherein the second imaging apparatus stops the second acquisition process on condition that the information in the height direction of the defect exceeds a predetermined size.

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