JP2009115681A - Image acquisition and display device - Google Patents

Abstract

【Task】
Conventionally, in a semiconductor wafer appearance inspection apparatus, there has been a problem that when a high-resolution camera is used to capture a microscopic image, the frame rate decreases, and when a low-resolution camera is used, the image quality deteriorates.
[Solution]
In the present invention, an imaging optical system that forms an image of a test object, an imaging unit that captures an image observed by the imaging optical system, a display unit that displays an image captured by the imaging unit, and the subject An image acquisition and display device comprising a moving unit that moves a specimen relative to the imaging optical system, the change detecting the change in the image acquisition and display device or the change in the image captured by the imaging unit A detection unit and a resolution control unit that sets a resolution based on a detection result of the change detection unit and controls the display unit to output an image corresponding to the resolution are provided.
[Selection] Figure 1

Description

  The present invention relates to an image acquisition display device that captures an image and displays the image on a display unit.

  In recent years, an image acquisition display device that captures an image and displays it on a display unit, such as a camera or a microscope, has been used. For example, in a semiconductor manufacturing process, an appearance inspection of a wafer is performed, and an image of a wafer to be inspected is picked up by an image pickup unit of a microscope and displayed on a display unit, and an observer confirms whether there is an abnormality. On the other hand, the circuit pattern formed on the wafer is miniaturized, and in order to observe the shape, size, or defect of the circuit pattern, it is necessary to use a microscope with high magnification and high resolution.

Conventionally, when displaying a microscope image of a wafer, image data input from a camera attached to the microscope is displayed on the screen of the display device at a fixed resolution without any processing (see, for example, Patent Document 1). .
JP 2003-057192 A

  However, in the prior art as described above, the resolution of an image to be captured and displayed is fixed. For this reason, when a high-resolution camera is used, a large amount of image data has to be processed, and there is a problem that the frame rate of an image to be displayed is lowered and it is difficult to display a smooth moving image. Further, when a low resolution camera is used, there is a problem that the frame rate is increased but the resolution is lowered, the image quality of the microscope image is deteriorated, and defects on the wafer are difficult to identify.

  In view of the above problems, an object of the present invention is to provide an image acquisition and display device capable of realizing a smooth moving image display following changes and displaying an image with high resolution during observation. .

  An image acquisition and display apparatus according to the present invention displays an imaging optical system that forms an image of a test object, an imaging unit that captures an image observed by the imaging optical system, and an image captured by the imaging unit. An image acquisition display device comprising: a display unit; and a moving unit that moves the test object relative to the imaging optical system, wherein the image acquired by the change of the image acquisition display device or the imaging unit And a resolution control unit that sets a resolution based on the detection result of the change detection unit and controls the display unit to output an image corresponding to the resolution. It is characterized by.

  In particular, the resolution control unit sets the resolution low when the change detection unit detects a change, and increases the resolution when the change detection unit does not detect a change.

  Furthermore, the change detection unit detects a change based on a difference between at least two images captured continuously by the imaging unit in time.

  Alternatively, the change detection unit detects a change depending on whether or not the moving unit has moved.

  In particular, the moving unit includes an XY stage and a Z stage, and the change detecting unit detects a change based on whether or not the moving unit moves in at least one direction in the XYZ directions.

  In addition, a dimmable illuminating unit that illuminates the test object is further provided, and the change detecting unit detects a change in light amount of the illuminating unit.

  In particular, the image acquisition and display device is an appearance inspection device that inspects the appearance of the semiconductor wafer using the object to be inspected as a semiconductor wafer.

  According to the present invention, in the image acquisition display device, a change in the image acquisition display device or a change in the image captured by the imaging unit is detected, a resolution corresponding to the change is set, and the image is displayed on the display unit. In addition, while realizing a smooth real-time display following a change, a high-resolution image can be automatically displayed and inspected when a gazeable image is acquired.

Hereinafter, an image acquisition display device according to the present invention will be described in detail with reference to the drawings. The image acquisition and display apparatus according to the present invention can be applied to an apparatus that captures and displays an image such as a camera or a microscope. However, in each of the following embodiments, the appearance of inspecting the appearance of a semiconductor wafer as the image acquisition and display apparatus An inspection apparatus will be described as an example.
(First embodiment)
FIG. 1 is an external view showing the configuration of a semiconductor wafer visual inspection apparatus 101 according to the first embodiment. In FIG. 1, the appearance inspection apparatus 101 mainly includes a microscope 102, a personal computer 103, and a position control unit 104.

  The microscope 102 includes a base 105, an arm 106, an observation unit main body 107, an objective lens stage 108, an objective lens 109, a Z-axis stage 112, and an XY stage 113. In FIG. 1, an imaging lens other than the objective lens is omitted.

  An imaging unit 111 is mounted on the observation unit main body 107, and image data captured by the imaging unit 110 is output to the personal computer 103 via the cable 111. On the base 105 of the microscope 102, a Z-axis stage 112 and an XY stage 113 are disposed so as to overlap each other, and a wafer 114 to be tested is placed on the XY stage 113. In this embodiment, the wafer 114 is manually placed on the XY stage 113 by an observer for inspection. However, in an automatic inspection apparatus or the like, a wafer transfer device is provided and the wafer to be inspected is provided. May be automatically placed on the XY stage 113.

  The XY stage 113 is connected to the position control unit 104 via a cable 115, and the Z-axis stage 112 is connected to the position control unit 104 via a cable 116. The position control unit 104 moves the wafer 114 in the X-axis direction, the Y-axis direction, and the Z-axis direction according to a command output from the personal computer 103 via the cable 117, and sets the relative position with respect to the microscope 102. Variable. Here, in this embodiment, the wafer 114 is moved, but the microscope 102 side may be moved. The wafer 114 is moved in the X-axis direction and the Y-axis direction, and the microscope 102 is moved in the Z-axis direction. You may make it move to a direction. The movement of the Z-axis stage 112 in the Z-axis direction may be a movement of the focus alignment mechanism of the microscope 102 in the Z-axis direction.

  The personal computer 103 includes a personal computer main body 118, a keyboard 119, a mouse 120, and a monitor 121. The personal computer main body 118 is loaded with software for displaying a microscope image, and the photographing conditions of the microscope 102 are input to the personal computer main body 118 by the keyboard 119 and the mouse 120. On the other hand, the image photographed by the microscope 102 is the wafer 114. Are displayed on the screen of the monitor 121 of the personal computer 103. An observer observes the screen of the monitor 121 of the personal computer 103 and inspects the appearance of the wafer 114.

  A lamp house 122 that illuminates the wafer 114 is connected to a personal computer body 118 of the personal computer 103 via a cable 123, and the lamp house 122 has a dimming function that adjusts the amount of light that illuminates the wafer 114 from the personal computer 103 side. Have.

  The appearance inspection apparatus 101 according to the present embodiment has two resolutions, a low resolution and a high resolution, as the resolution of an image captured by the imaging unit 110. For example, 640 × 480 pixels are used for low resolution, and 1280 × 1024 pixels are used for high resolution.

  Here, a frame rate at the time of displaying an image photographed by the imaging unit 110 on the screen of the monitor 121 of the personal computer 103 will be described. Image data captured by the imaging unit 110 is read by the personal computer 103 via the cable 111. The image data read by the personal computer 103 is displayed on the screen of the monitor 121 after image processing such as white balance processing and color interpolation processing. In this case, for example, in the case of color, in the case of 8-bit gradation with 3 colors of RGB, ((number of pixels) × 8 × 3) bit data is output to the personal computer 103 via the cable 111, and a microscope image of the personal computer 103 An image having a data amount of ((number of pixels) × 8 × 3) bits must be processed by display software. For this reason, when the number of pixels of the image captured by the imaging unit 110 increases, the processing amount increases, and the time from when one captured image is captured until it is displayed on the monitor 121 becomes longer. As a result, the frame rate for displaying images continuously decreases.

  For example, in the case of a high-resolution image ((1280 × 1024) × 8 × 3) ≈4.9 MByte, the amount of data is low ((640 × 480) × 8 × 3) ≈0.9 MByte. The amount of data is close to about 5 times the amount of data. Now, assuming that there is a processing capacity of 30 MByte image data per second, a frame rate of about 30 frames / second is obtained for a low resolution image, but a frame rate of about 6 frames / second is obtained for a high resolution image. Only rate is obtained. For this reason, the movement of the image displayed on the monitor 121 becomes slow. In particular, when the XY stage 113 on which the wafer 114 is placed is moved, or when the Z-direction movable unit 108 is moved up and down in the Z-axis direction, the monitor 121 is moved. There arises a problem that a time difference occurs between the screen displayed on the screen and the actual operation, which makes it difficult for the observer to perform alignment.

  Therefore, the appearance inspection apparatus 101 according to the present embodiment changes the state of the appearance inspection apparatus 101 itself, for example, when the XY stage 113 on which the wafer 114 is placed is moved, when the Z-axis stage 112 is moved up and down, When the amount of light 122 is changed, or when the image captured by the imaging unit 110 is changed, the resolution of the image captured and processed by the imaging unit 110 is set to a low resolution. When there is no change, it operates so as to set the resolution of an image to be imaged and processed by the imaging unit 110 to a high resolution.

  Here, for easy understanding, the configuration of the appearance inspection apparatus 101 shown in FIG. 1 will be described with reference to the block diagram of FIG. In FIG. 2, the same reference numerals as those in FIG. FIG. 2 is a block diagram illustrating the functions of the personal computer 103. The personal computer 103 includes a control unit 401, a resolution control unit 402, an image processing unit 403, a memory 404, and an operation unit 405. The lens 406 is an imaging lens.

  The control unit 401 is operated by software of the personal computer 103 and controls the entire appearance inspection apparatus 101.

  The resolution control unit 402 controls the frame rate of the image data captured by the imaging unit 110 in response to a command from the control unit 401.

  The image processing unit 403 performs white balance processing, color interpolation processing, or the like on the image data read from the imaging unit 110 in accordance with a command from the control unit 401 and displays the image data on the monitor 121, or the memory 404 via the control unit 401. Save to.

  The operation unit 405 corresponds to the keyboard 119 and the mouse 120 of the personal computer 103 in FIG. 1, and inputs an instruction for focusing the microscope 102 while viewing the screen displayed on the monitor 121, and the Z-axis stage 112. Or an operation input of the XY stage 113 is performed, or an operation of dimming the light amount of the lamp house 122 is performed. In response to the operation of the operation unit 405, the control unit 401 instructs the position control unit 104 to drive the Z-axis stage 112 and the XY stage 113, and the position of the wafer 114 is set to the X-axis direction, the Y-axis direction, and the Z-axis direction. Move to. Alternatively, the light amount of the lamp house 122 is varied.

  For example, the observer operates the operation unit 405 to move the XY stage 113 and the Z-axis stage 112 when the appearance inspection is performed by placing the semiconductor wafer 114 as the test object on the XY stage 113. Align so that you can see the part you want to see. Alternatively, the light amount of the lamp house 122 is adjusted so that the portion to be observed can be seen well. Further, the observer performs such an operation while viewing the image displayed on the monitor 121.

  Next, the overall operation of the appearance inspection apparatus 101 according to the present embodiment will be described with reference to the flowchart of FIG. FIG. 3 is a flowchart depicting mainly the processing of the microscope image display software operating on the control unit 401. Therefore, unless otherwise specified, the control subject is the control unit 401 in which the microscope image display software is operating.

  In the following description, it is assumed that the imaging unit 110 includes the imaging unit 110 having a variable frame rate mechanism. Note that the number of pixels output from the imaging unit 110 can be increased or decreased by the variable frame rate mechanism.

  Hereinafter, the flowchart of FIG. 3 will be described in order. The observer always operates the appearance inspection apparatus 101 while the flowchart is executed. For example, while observing the image of the wafer 114 displayed on the monitor 121, the observer performs an operation of moving to a position to be observed using the operation unit 405 or adjusts the brightness of the lamp house 122. In addition, the flowchart which shows the process which moves the Z-axis stage 112 and the XY stage 113 according to these operation content, and the process which light-controls the lamp house 122 is abbreviate | omitted, and only the process regarding an external appearance inspection is demonstrated here.

  (Step S201) An appearance inspection is started.

  (Step S <b> 202) The control unit 401 receives an output from a detection mechanism (not shown) or a user input as a signal related to completion of placement of the wafer 114 on the XY stage 113, and detects completion of placement of the wafer 114.

  (Step S203) The frame rate of the imaging unit 110 is set according to a predetermined resolution. Here, the low resolution is set.

  (Step S <b> 204) The image data read by the resolution control unit 402 from the imaging unit 110 with a predetermined resolution is subjected to image processing by the image processing unit 403 and displayed on the monitor 121 via the control unit 401. The displayed image data is also temporarily stored in the memory 404.

  (Step S205) It is determined whether or not the observer has performed an end operation of the appearance inspection using the operation unit 405. When the operation for ending the inspection is performed, the process proceeds to Step S206, and the appearance inspection is ended. If the inspection end operation has not been performed, the process proceeds to step S207 to continue the appearance inspection.

  (Step S206) The appearance inspection is finished.

  (Step S207) The control unit 401 obtains a difference between the image newly read by the resolution control unit 402 from the imaging unit 110 and processed by the image processing unit 403 and the image stored in the memory 404 in step S204. In addition, the method of calculating | requiring a difference calculates | requires an absolute value by subtracting per pixel, for example, and averages the value of each pixel for 1 screen. Alternatively, in order to speed up the processing, both the image stored in the memory 404 and the newly acquired image may be partially thinned in the same manner to obtain a difference, or only the central portion of the image The difference may be obtained with

  In this way, a difference between temporally continuous images is obtained.

  (Step S208) It is determined whether or not the difference is greater than or equal to a predetermined value set in advance. If it is equal to or greater than the predetermined value, the process proceeds to step S209. If it is equal to or smaller than the predetermined value, the process proceeds to step S210. For example, in FIG. 4, when the XY stage 113 is moved in an oblique direction, the image 301 changes to the image 302 and further to the image 303, so that the difference increases. On the other hand, when the XY stage 113 is not moved, there may be some change due to noise or the like, but since the position of the test object remains almost unchanged in the image 301, the difference becomes small. Therefore, it is desirable to set the predetermined value so that it does not malfunction due to noise or the like.

  (Step S209) If the difference is greater than or equal to a predetermined value set in advance, the resolution of the image processed by the image processing unit 403 is set to a low resolution. If the resolution is already set low, it is maintained as it is. After processing, the process returns to step S204.

  (Step S210) If the difference is less than a predetermined value set in advance, the resolution of the image processed by the image processing unit 403 is set to a high resolution. If the resolution is already set, it is maintained as it is. After processing, the process returns to step S204.

  Thereafter, the processing from step S204 to step S209 or step S210 is repeated.

During execution of the above flowchart, the observer performs the following operation in order to inspect the appearance of the wafer 114.
(1) The observer operates the operation unit 405 to focus the microscope 102 on the wafer 114. When adjusting the focus position, the Z-axis stage 112 may be moved up and down in the Z-axis direction via the position control unit 104. Although not shown in FIG. 1, the focus adjustment mechanism of the microscope 102 itself is operated. It doesn't matter. Further, the focus may be automatically adjusted sequentially. For example, in the image 304 shown in FIG. 5, the subject 351 is thick with a blurred outline in the image 304 shown in FIG. 5, but when the Z-axis stage 112 is moved in the Z-axis direction, an image 305 is obtained. In addition, the blur of the outline of the subject 351 is reduced. Further, when the Z-axis stage 112 is moved in the Z-axis direction, the contour of the subject 351 becomes sharper and thinner as shown in the image 306.
(2) The observer operates the operation unit 405 to move the XY stage 113 in the X-axis direction or the Y-axis direction so that a portion to be observed on the wafer 114 is projected onto the imaging unit 110. For example, in the image 301 of FIG. 4, the subject 351 is shown in the upper left of the screen, but when the XY stage 113 is moved in an oblique direction, the subject 351 moves from the upper left of the screen to the center of the screen as in the image 302. Further, when the XY stage 113 is moved in an oblique direction, the subject 351 moves from the center of the screen to the lower right of the screen as in the image 303.
(3) The observer operates the operation unit 405 to adjust the amount of illumination of the lamp house 122. For example, in the image 307 in FIG. 6, the subject 351 appears dark, but when the illumination becomes brighter by increasing the amount of illumination of the lamp house 122, the subject 351 appears bright like the image 308. Further, when the illumination of the lamp house 122 becomes brighter, the subject 351 appears brighter like an image 309.

  When any of the above operations (1), (2), and (3) is performed, the difference obtained in step S207 in the flowchart of FIG. Since image processing is performed at high speed, the image is displayed on the screen of the monitor 121 at a high frame rate following changes in the amount of illumination light of the XY stage 113, the Z-axis stage 112, and the lamp house 122.

  On the other hand, if any of the above operations (1), (2), and (3) is not performed, the difference obtained in step S207 in the flowchart of FIG. Since image processing is performed with high resolution, a high-definition image is displayed on the screen of the monitor 121.

  In addition to the above (1), (2) and (3), the same effect can be obtained when the magnification of the variable magnification optical system changes. For example, in the image 310 of FIG. 7, the subject 351 appears small in the center of the screen, but when the magnification of the zoom optical system is slightly increased, the subject 351 is slightly enlarged in the center of the screen as in the image 311. . Further, when the magnification of the variable power optical system is increased, the subject 351 is enlarged on the entire screen as an image 312. As a result, since the difference obtained in step S207 changes, the same processing can be performed based on the flowchart of FIG.

  As described above, the appearance inspection apparatus 101 according to this embodiment moves the XY stage 113 on which the wafer 114 is placed, moves the Z-axis stage 112 up and down, changes the light amount of the lamp house 122, or captures an image. When the image captured by the unit 110 is changed, the resolution of the image processed by the image processing unit 403 is set to a low resolution, and when there is no change as described above, the image processing unit 403 Since the resolution of the image to be processed is set to a high resolution, it is possible to realize a smooth moving image display following the movement and an inspection with a high resolution image.

  In this embodiment, the difference is obtained from two images that are temporally continuous. However, two or more images may be used, and every few images that are not temporally continuous are used. It doesn't matter.

  In this embodiment, the resolution may be different between the image stored in the memory 404 to be compared in step S208 and the newly acquired image. If the pixel values of the images are simply compared at this time, there may be no comparison target pixel in the low-resolution image. In this case, the image processing unit 403 interpolates the low-resolution image in accordance with the size of the high-resolution image so as to be the same as the size of the high-resolution image, and then the pixels of each other image. Compare the values. Alternatively, the image processing unit 403 creates sample data having the same number of pixels as the low resolution from the high resolution image by thinning out pixels at predetermined intervals so that the size of the high resolution image becomes the same as the size of the low resolution image. The sample data may be compared with the low resolution image.

(Second Embodiment)
Next, an appearance inspection apparatus 101 according to the second embodiment will be described. The appearance inspection apparatus 101 according to the second embodiment has the same configuration as the appearance inspection apparatus 101 of FIGS. 1 and 2 according to the first embodiment. The difference from the first embodiment is the processing of step S207 and step S208 in the flowchart described with reference to FIG. 3 of the first embodiment. In the first embodiment, the difference between two temporally continuous images is obtained to determine whether or not the image has changed. However, in this embodiment, both the Z-axis stage 112 and the XY stage 113 or both are small. And the presence or absence of a change in the image when one of them operates.

  Next, processing of the appearance inspection apparatus 101 according to the present embodiment will be described using the flowchart of FIG. In FIG. 8, the processes other than step S307 and step S308 are the same as the processes of steps S201 to S206, steps S209, and S210 of FIG. Here, only the processing of step S307 and step S308 will be described.

  (Step S307) Whether or not the Z-axis stage 112 and the XY stage 113 are moved is checked. Since the control unit 401 controls the Z-axis stage 112 and the XY stage 113, if both or at least one of the Z-axis stage 112 and the XY stage 113 is controlled after the previous check, it is determined that there is movement, and the Z-axis stage If neither 112 nor XY stage 113 is controlled, it is determined that there is no movement. It should be noted that not only the presence / absence of the movement of the Z-axis stage 112 and the XY stage 113 but also the movement amount after the previous check may be obtained. In this case, if the check interval is constant, it can be considered as a moving speed.

  (Step S308) Branch processing is performed depending on whether the Z-axis stage 112 or the XY stage 113 has moved. If both or at least one of the Z-axis stage 112 and the XY stage 113 has moved, the process proceeds to step S209, and if not, the process proceeds to step S210. When the movement amount or movement speed of the Z-axis stage 112 or the XY stage 113 is obtained in step S307, the process proceeds to step S209 if these values are greater than or equal to a predetermined value, and in the case where these values are less than or equal to the predetermined value, step S210 is performed. Can be processed to proceed. By processing in this way, if the amount of movement is small, the process proceeds to the next step S210, so that it can be processed with high resolution.

  Thereafter, the processing from step S204 to step S209 or step S210 is repeated.

  As described above, in the appearance inspection apparatus 101 according to the present embodiment, when the appearance inspection of the wafer 114 is performed with a microscope, both or at least one of the Z-axis stage 112 and the XY stage 113 is moved. If the image processing unit 403 sets the resolution of the image to be processed to a low resolution and there is no movement, the image processing unit 403 sets the resolution of the image to be processed to a high resolution. It is possible to realize moving image display and inspection with a high-resolution image.

  Note that when the Z-axis stage 112 or the XY stage 113 is moved in the X-axis direction, the Y-axis direction, and the Z-axis direction as in the present embodiment, the position of the wafer 114 changes as described with reference to FIG. As described in the first embodiment, the same effect as the method of obtaining the difference between the preceding and following images can be obtained.

(Third embodiment)
Next, an appearance inspection apparatus 101 according to the third embodiment will be described. The appearance inspection apparatus 101 according to the third embodiment has the same configuration as the appearance inspection apparatus 101 of FIGS. 1 and 2 according to the first embodiment. The difference from the above-described embodiments is that the illumination light of the lamp house 122 is not determined based on the change in the image captured by the imaging unit 110 or the presence or absence of the movement of the XY stage 113 or the Z-axis stage 112. Is determined by whether or not the light is adjusted.

  Next, processing of the appearance inspection apparatus 101 according to the present embodiment will be described with reference to the flowchart of FIG. In FIG. 9, processes other than step S507 and step S508 are the same as the processes of steps S201 to S206, steps S209, and S210 of FIG. Here, only the processing of step S507 and step S508 will be described.

  (Step S507) It is checked whether or not the illumination light of the lamp house 122 has been dimmed. Since the control unit 401 dims the illumination light of the lamp house 122, the previous dimming position (light quantity) is recorded in the memory 404, and if the dimming position has changed, dimming is present (the light quantity changes). If the dimming position has not changed, it is determined that there is no dimming (the amount of light does not change). In addition, you may obtain | require not only whether the illumination light of the lamp house 122 was dimmed but the dimming amount.

  (Step S508) Branch processing is performed depending on whether or not the light quantity of the lamp house 122 has changed. If the light amount of the lamp house 122 has changed, the process proceeds to step S209, and if not, the process proceeds to step S210. When the dimming amount of the illumination light of the lamp house 122 is obtained, the process can proceed to step S209 if these values are equal to or larger than a predetermined value, and to step S210 if they are equal to or smaller than the predetermined value. By processing in this way, when the light control amount is small (when the change in light amount is small), the process proceeds to the next step S210, so that the high resolution can be processed.

  Thereafter, the processing from step S204 to step S209 or step S210 is repeated.

  As described above, in the appearance inspection apparatus 101 according to the present embodiment, when the light amount of the lamp house 122 is changed in the appearance inspection of the wafer 114 with a microscope, the resolution of the image processed by the image processing unit 403 is changed. When the resolution is set to low and there is no change in the amount of light, the resolution of the image processed by the image processing unit 403 is set to a high resolution, so that a smooth moving image display that follows the change in brightness that illuminates the wafer 114 and It is possible to realize inspection with a high-resolution image.

  Note that when the light amount of the lamp house 122 is changed as in this embodiment, the light amount of the subject changes. Therefore, as described in the first embodiment, the method of obtaining the difference between the preceding and following images can also be used. Changes can be detected.

(Fourth embodiment)
Next, an appearance inspection apparatus 101 according to the fourth embodiment will be described. The appearance inspection apparatus 101 according to the fourth embodiment has the same configuration as the appearance inspection apparatus 101 of FIGS. 1 and 2 according to the first embodiment. The difference from the above-described embodiments is that a change in an image captured by the imaging unit 110, a presence or absence of movement of the XY stage 113 or the Z-axis stage 112, and a change in the amount of illumination light of the lamp house 122 are determined. Instead of determining whether the magnification has changed. In order to change the magnification, a plurality of magnification objective lenses 109 mounted on the objective lens stage 108 in FIG. 1 may be switched, or a microscope having a variable magnification optical system such as a zoom lens of a camera may be used. Absent.

  In this case, for example, in step S507 in the flowchart of FIG. 9, instead of checking the operation of the light control unit, it is checked whether or not the magnification of the optical system has been changed. Further, in the next step S508, if the magnification of the optical system is changed instead of changing the amount of light, the process proceeds to step S209 to set a low resolution, and if the magnification of the optical system is not changed, the process proceeds to step S210. Set to high resolution. Thereafter, the processing from step S204 to step S209 or step S210 is repeated.

  As described above, in the appearance inspection apparatus 101 according to the present embodiment, when performing an appearance inspection of the wafer 114 with a microscope capable of changing the magnification of the optical system, if the magnification of the optical system changes, the image processing unit 403 When the resolution of the image to be processed is set to a low resolution and there is no change in magnification, the resolution of the image to be processed by the image processing unit 403 is set to a high resolution, so that the change in brightness that illuminates the wafer 114 is followed. Smooth moving image display and inspection with high-resolution images can be realized.

  Even when the magnification of the optical system changes, as described in the first embodiment, a change in magnification can also be detected by a method of detecting a change by obtaining a difference between preceding and following images.

  As described above in each embodiment, the appearance inspection apparatus 101 detects a change in the state of the apparatus or a change in an image captured by the imaging unit, sets a resolution according to the change, and displays an image on the display unit. Is displayed. In particular, if there is a change, set to low resolution to achieve a smooth video display following the change, but if there is no change, set to high resolution to display a high-definition image and display the test object Can be inspected.

  In each embodiment, the control unit 401 uses the resolution control unit 402 to change the resolution of the image displayed on the monitor by changing the frame rate of the imaging unit 110. However, the output frame rate of the imaging unit 110 is sufficient. If it is very fast, the processing mode of the image processing unit 403 may be changed as follows. For example, when there is no image change or device change, the resolution control unit 402 controls to perform image processing on all pixel signals output from the imaging unit 110, while there is such a change. Alternatively, if it is equal to or greater than the threshold, the resolution control unit 402 controls the image processing unit 403 so that the pixel signal output from the imaging unit 110 is captured at a predetermined interval, and an image is obtained using the thinned pixel signal. The processing unit 403 may perform image processing. When the processing speed of the image processing unit 403 is an impediment to real-time display, real-time display is possible in this way.

  Further, the position control unit 104 may be incorporated in the interface of the personal computer 103 or in the microscope observation apparatus 103a. Alternatively, the portion of the personal computer 103 may be configured with dedicated hardware and integrated with the microscope 102.

  Furthermore, for ease of understanding, in each embodiment, two types of resolution, low resolution and high resolution, are used, but they may be divided into a plurality of resolutions. For example, numerical values such as the moving amount and moving speed of the Z-axis stage 112 and the XY stage 113, the light control amount of the illumination light of the lamp house 122, and the like, as in the difference of the first embodiment, are not determined based on whether or not there is a change. If the predetermined value is set in two stages so that it can be distinguished from the predetermined value, it can be divided into three resolutions: low resolution, medium resolution, and high resolution, and a smoother display that follows each change. Can be realized.

It is a block diagram of the whole external appearance inspection apparatus 101 of each embodiment. It is a block diagram of the appearance inspection apparatus 101 of each embodiment. It is a flowchart which shows the process of the external appearance inspection apparatus 101 of 1st Embodiment. It is an auxiliary figure for explaining a 1st embodiment. It is an auxiliary figure for explaining each embodiment. It is an auxiliary figure for explaining each embodiment. It is an auxiliary figure for explaining each embodiment. It is a flowchart which shows the process of the external appearance inspection apparatus 101 of 2nd Embodiment. It is a flowchart which shows the process of the external appearance inspection apparatus 101 of 3rd Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 ... Appearance inspection apparatus 102 ... Microscope 103 ... Personal computer 104 ... Position control part 110 ... Imaging part 112 ... Z-axis stage 113 ... XY stage 114 ... Wafer 118 ..PC main body 121 ... monitor 122 ... lamp house 401 ... control unit 402 ... resolution control unit 403 ... image processing unit 404 ... memory 405 ... operation unit

Claims (7)

An imaging optical system that forms an image of the test object, an imaging unit that captures an image observed by the imaging optical system, a display unit that displays an image captured by the imaging unit, and the test object An image acquisition and display device comprising a moving unit that moves relative to the imaging optical system,
A change detection unit that detects a change in the image acquisition display device or a change in an image captured by the imaging unit;
An image acquisition and display apparatus, comprising: a resolution control unit configured to set a resolution based on a detection result of the change detection unit and control the display unit to output an image corresponding to the resolution. The image acquisition display device according to claim 1,
The resolution control unit sets the resolution low when the change detection unit detects a change, and increases the resolution when the change detection unit does not detect a change. The image acquisition display device according to claim 2,
The change detection unit detects a change based on a difference between at least two images captured continuously in time by the imaging unit. The image acquisition display device according to claim 2,
The image detecting and displaying apparatus, wherein the change detecting unit detects a change depending on whether or not the moving unit has moved. In the image acquisition display device according to claim 4,
The moving unit includes an XY stage and a Z stage,
The change detection unit detects a change based on presence / absence of movement of the moving unit in at least one direction in an XYZ direction. In the image acquisition display device according to claim 1 or 2,
Further provided is a dimmable illumination unit that illuminates the test object,
The said change detection part detects the change of the light quantity of the said illumination part. The image acquisition display apparatus characterized by the above-mentioned. The image acquisition and display device according to any one of claims 1 to 6 is an appearance inspection device that inspects an appearance of the semiconductor wafer using the test object as a semiconductor wafer.

Images