JP2013072824A - Image acquisition device and image acquisition method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily perform focus adjustment of a light receiving unit.SOLUTION: An image acquisition device comprises: an image capturing unit 2 for capturing an image of an imaging region that is linear on a glass substrate 9; and a movement mechanism for moving the glass substrate 9 in a direction crossing the imaging region. The image capturing unit 2 includes a light irradiation part 21 and a light receiving part 23. The irradiation part 21 irradiates the imaging region with light and light from the imaging region is guided to a line sensor of the light receiving part 23. In the image acquisition device, due to the fact that a light receiving part rotating mechanism rotates the light receiving part 23, a detection angle θ2, formed between an optical axis J2 of the light receiving part 23 and a normal line N of the glass substrate 9, is changed. The image capturing unit 2 further includes a light receiving part moving mechanism for moving the light receiving part 23 along the light axis J2. By controlling a light receiving part moving mechanism on the basis of a displacement amount of the detection angle θ2, a position P conjugated with a light receiving surface of the line sensor on the optical axis J2 is arranged on a surface of the glass substrate 9. Accordingly, focus adjustment of the light receiving part 23 is easily performed.

Description

  The present invention relates to a technique for acquiring an image of a thin film pattern formed on a substrate.

  Conventionally, in various fields, a pattern formed on a film-like or plate-like substrate has been inspected. For example, in the pattern inspection apparatus disclosed in Patent Document 1, a wiring pattern formed on a resin film is inspected. In the pattern inspection apparatus, an image with good contrast can be obtained by using an LED (Light Emitting Diode) that emits only light having a wavelength of 500 nm or more as a light source.

  In the film thickness measuring device disclosed in Patent Document 2, light is irradiated from a semiconductor laser to a transparent polyester film, and the intensity of specular reflection light is detected by a silicon photodiode. The semiconductor laser and the silicon photodiode are moved within the range of 0 ° to 90 ° by the stepping motor, and the light incident angle is changed.

JP 2006-112845 A JP 2004-101505 A

  By the way, in recent years, FPD (Flat Panel Display) is provided in various electronic devices. In the manufacture of such a display device, when visual inspection of a transparent pattern such as a transparent electrode formed on a base material is performed, for example, light is irradiated from the light irradiation unit to the imaging region on the base material to receive light. The pattern image is acquired by receiving the reflected light at the part. In this case, it is conceivable to obtain a high-contrast image by changing the detection angle formed by the optical axis from the imaging region to the light receiving unit and the normal line of the base material to change the interference state of the received light. It is done.

  On the other hand, if the detection angle is changed by rotating the light receiving portion, the position conjugate with the light receiving surface of the light receiving portion is displaced from the surface of the base material. A mechanism that arranges on the surface of the substrate (that is, performs focus adjustment) is required. However, in order to move up and down a large base material, a large lift mechanism is required, or focus adjustment cannot be performed on a plurality of positions when simultaneously acquiring images at a plurality of positions on the base material. Various constraints arise. Therefore, another easy method for adjusting the focus of the light receiving unit while changing the detection angle is required.

  The present invention has been made in view of the above problems, and an object of the present invention is to easily perform focus adjustment of a light receiving unit while changing a detection angle.

  The invention according to claim 1 is an image acquisition device for acquiring an image of a thin film pattern formed on a substrate, an imaging unit for imaging a linear imaging region on the substrate, and the substrate A moving mechanism that moves relative to the imaging region in a direction intersecting the imaging region, and a control unit, and the imaging unit emits light having a wavelength that is transmissive to the thin film pattern. A light receiving unit, a line sensor, and a light receiving unit including an optical system that guides light from the imaging region irradiated with the light to the line sensor, an optical axis of the optical system, and a method of the base material A detection angle changing mechanism that changes a detection angle formed with a line, and a light receiving unit moving mechanism that moves the light receiving unit along the optical axis, and the control unit is configured to change the detection angle based on a displacement amount of the detection angle. By controlling the light receiving unit moving mechanism, The light receiving surface conjugate with the position of the line sensor is disposed on the thin film pattern on an axis.

  A second aspect of the present invention is the image acquisition device according to the first aspect, wherein the imaging unit rotates the light irradiation unit around an axis parallel to the imaging region and passing through the conjugate position. A light irradiation unit rotation mechanism that moves; the light irradiation unit rotation mechanism is fixed to the light receiving unit; and the control unit controls the light irradiation unit rotation mechanism based on a displacement amount of the detection angle. By doing so, the irradiation angle formed by the optical axis extending from the light irradiation unit to the imaging region and the normal line is made to coincide with the detection angle.

  Invention of Claim 3 is an image acquisition apparatus of Claim 1, Comprising: The predetermined | prescribed angular range centering on the axis | shaft which the said light irradiation part passes along the said conjugate position parallel to the said imaging region Irradiating the imaging region with the light, and the light irradiating unit is fixed to the light receiving unit, and on the surface perpendicular to the axis, the normal line is opposite to the optical axis. An angular position that is inclined by the detection angle about an axis is included in the predetermined angle range.

  Invention of Claim 4 is an image acquisition apparatus in any one of Claim 1 thru | or 3, Comprising: When the said control part controls the said moving mechanism based on the displacement amount of the said detection angle, The position of the imaging region with respect to the base material before and after the change of the detection angle is matched.

  A fifth aspect of the present invention is the image acquisition device according to any one of the first to third aspects, further comprising another imaging unit having the same configuration as the imaging unit.

  Invention of Claim 6 is an image acquisition method which acquires the image of the thin film pattern formed on the base material with an image acquisition apparatus, Comprising: The said image acquisition apparatus is permeable with respect to the said thin film pattern. A light irradiating unit that emits light having a wavelength, a line sensor, and a light receiving unit that includes an optical system that guides light from a linear imaging region irradiated with the light to the line sensor. An acquisition method includes: a) changing a detection angle formed by the optical axis of the optical system and a normal line of the base material; and b) moving the light receiving unit along the optical axis to thereby move the optical axis. Placing a position conjugate with the light receiving surface of the line sensor on the thin film pattern; and c) moving the substrate relative to the imaging region in a direction intersecting the imaging region. Is provided.

  Invention of Claim 7 is an image acquisition method of Claim 6, Comprising: Before the said c) process, d) The said base material is moved relatively with respect to the said imaging area | region, The method further includes the step of matching the position of the imaging region with respect to the base material before and after the change of the detection angle.

  According to the present invention, it is possible to easily adjust the focus of the light receiving unit while changing the detection angle.

  In the invention of claim 2, the irradiation angle can be easily matched with the detection angle, and in the invention of claim 3, the control of the image pickup unit can be simplified.

It is a figure which shows schematic structure of an image acquisition apparatus. It is a side view of an imaging unit. It is a rear view of a light irradiation part rotation mechanism. It is a figure which shows an imaging unit. It is a block diagram which shows the function structure of an image acquisition apparatus. It is a figure which shows the flow of operation | movement of an image acquisition apparatus. It is a figure which shows the example of a profile. It is a figure which shows the flow of the operation | movement which concerns on angle adjustment. It is a figure for demonstrating the operation | movement which concerns on angle adjustment. It is a figure for demonstrating the operation | movement which concerns on angle adjustment. It is a figure for demonstrating the operation | movement which concerns on angle adjustment. It is a figure which shows the other example of an image acquisition apparatus. It is a figure which shows the other example of a light irradiation part. It is a figure which shows the further another example of an image acquisition apparatus. It is a figure which shows the further another example of an image acquisition apparatus. It is a figure which shows the further another example of an image acquisition apparatus.

  FIG. 1 is a diagram showing a schematic configuration of an image acquisition apparatus 1 according to an embodiment of the present invention. The image acquisition device 1 acquires and displays a pattern image that is an image of a multilayer thin film pattern formed on a substrate. In FIG. 1, the substrate is a glass substrate. The thin film pattern is, for example, a transparent electrode film. In the present embodiment, the base material and the thin film pattern are covered with the transparent film. In practice, other layers such as an antireflection film are also provided on the substrate. In the following description, the thin film pattern is simply referred to as “pattern”. The base material and the film on the base material are collectively referred to as “glass substrate 9” or “display target”. The glass substrate 9 is used for manufacturing a capacitive touch panel.

  The image acquisition apparatus 1 includes a moving mechanism 11 that moves the glass substrate 9, a film thickness meter 12, an imaging unit 2, and a computer 3. The moving mechanism 11 includes a stage 41 that holds the glass substrate 9 on the upper surface, a first moving unit 42 that moves the stage 41 in the X direction in FIG. 1 parallel to the main surface of the glass substrate 9, and the glass substrate 9. And a second moving unit 43 that moves the first moving unit 42 in the Y direction that is parallel to the principal surface of the first surface and perpendicular to the X direction. Each of the first moving unit 42 and the second moving unit 43 includes a motor, a ball screw, a guide rail, and the like. The moving mechanism 11 is a mechanism that moves a base material, which is a main part of the glass substrate 9, relative to an imaging region 90 described later. A mechanism for rotating the stage 41 around an axis parallel to the Z direction in FIG. 1 perpendicular to the X direction and the Y direction may be added to the moving mechanism 11.

  The film thickness meter 12 is an optical interference type spectral film thickness meter, which irradiates the measurement light onto the glass substrate 9 and acquires the spectrum of the reflected light. On the premise of a preset film structure, the film thickness of each layer is calculated, and the film thickness of each layer is determined by fitting the spectrum obtained by calculation to the spectrum obtained by measurement.

  The imaging unit 2 includes a light irradiation unit 21 that emits light toward the imaging region 90 on the glass substrate 9 and a light receiving unit 23 that receives reflected light from the imaging region 90. The light irradiation unit 21 emits light having a wavelength that is transparent to the pattern. The light is irradiated at least to a linear imaging region 90 (shown by a thick line in FIG. 2 described later) extending in the X direction. The light irradiation unit 21 includes a plurality of LEDs arranged in the X direction, and an optical system that uniformizes light from the LEDs and guides the light to the imaging region 90. The light receiving unit 23 includes a line sensor 231 in which a plurality of light receiving elements are arranged linearly (one-dimensionally), and an optical system 232 that guides light from the imaging region 90 to the line sensor 231. The optical system 232 is provided inside the lens barrel 233. In FIG. 1, a position optically conjugate with the light receiving surface of the line sensor 231 on the optical axis J2 of the optical system 232 (hereinafter referred to as “focus position”) is indicated by a point P.

  When acquiring a pattern image to be described later, the glass substrate 9 is moved in a direction intersecting the imaging region 90 by the moving mechanism 11. That is, the moving mechanism 11 is a mechanism that moves the base material of the glass substrate 9 relative to the imaging region 90. In the present embodiment, the glass substrate 9 moves in the Y direction perpendicular to the imaging region 90, but the imaging region 90 may be inclined with respect to the movement direction. In the following description, the base material and the pattern are distinguished from each other as necessary. However, since the majority of the display target (glass substrate 9) is the base material, the display target is handled as a display. The object and the base material are explained without strictly distinguishing them.

  FIG. 2 is a side view of the imaging unit 2. 2 shows the imaging unit 2 in a state where the optical axis J2 (of the optical system 232) of the light receiving unit 23 is parallel to the Z direction for convenience of illustration (the same applies to FIG. 3 described later). The imaging unit 2 includes a light irradiation unit rotation mechanism 22 that rotates the light irradiation unit 21 (see FIG. 3 to be described later), a light reception unit rotation mechanism 24 that rotates the light reception unit 23, and a light reception unit 23 that has an optical axis. And a light receiving unit moving mechanism 25 that moves along J2.

  The light receiving unit rotating mechanism 24 includes a motor (for example, a stepping motor) 241 attached to the support block 201, and the tip of the rotating shaft of the motor 241 is fixed to the base unit 251 of the light receiving unit moving mechanism 25. The base portion 251 has a long shape in one direction (hereinafter also referred to as “longitudinal direction”). The base portion 251 has a guide rail extending in the longitudinal direction, a ball screw extending in the longitudinal direction, and a transmission mechanism. A motor 252 for rotating the ball screw is attached. The base portion 234 of the light receiving portion 23 is fixed to the nut (moving portion) of the ball screw, and the above-described lens barrel 233 is attached to the base portion 234. In the imaging unit 2, the light receiving unit 23 moves in the longitudinal direction of the base unit 251 by driving the motor 252. The longitudinal direction of the base portion 251 is parallel to the optical axis J2 of the light receiving portion 23, and the light receiving portion 23 can be moved along the optical axis J2 by the light receiving portion moving mechanism 25.

  FIG. 3 is a rear view of the light irradiation unit rotating mechanism 22. The light irradiation unit rotation mechanism 22 has an arcuate guide plate 221 centered on the focus position P, and the guide plate 221 is fixed to the barrel 233 of the light receiving unit 23. The guide plate 221 is a plate member parallel to the Y direction and the Z direction. The light irradiation unit 21 is provided with a gear 223 and two guide rollers 224 that rotate about an axis parallel to the X direction. In the guide plate 221, a rack 222 is provided on the outer arc-shaped edge with respect to the focus position P (that is, the edge farther from the focus position P of the two arc-shaped edges), and the gear 223 is attached to the rack 222. Match. Further, a guide groove with which the guide roller 224 is engaged is formed on the inner arc-shaped edge of the guide plate 221. In the imaging unit 2, the light irradiation unit 21 moves along the arc-shaped edge of the guide plate 221 by rotating a gear 223 by a motor (not shown). That is, the light irradiating unit rotating mechanism 22 rotates the light irradiating unit 21 around an axis (virtual axis) parallel to the imaging region 90 and passing through the focus position P. The gear 223 and the guide roller 224 are a part of the light irradiation unit rotating mechanism 22.

  As described above, FIGS. 2 and 3 show the imaging unit 2 in a state where the optical axis J2 of the light receiving unit 23 (that is, the moving direction of the light receiving unit 23) is parallel to the Z direction for the sake of illustration. However, in the actual imaging unit 2, as shown in FIG. 4, the optical axis J2 from the imaging region 90 to the light receiving unit 23 is inclined with respect to the Z direction. Then, the detection angle θ2 is changed by the light receiving unit rotating mechanism 24 (see FIG. 2) using the angle θ2 formed by the optical axis J2 of the light receiving unit 23 and the normal line N of the glass substrate 9 as a detection angle. Further, the irradiation angle θ1 is changed by the light irradiation unit rotating mechanism 22 with the angle θ1 formed by the optical axis J1 extending from the light irradiation unit 21 to the imaging region 90 and the normal N as an irradiation angle. In FIG. 1 and FIG. 4, the rotation axis by the light receiving unit rotation mechanism 24 is shown with a symbol K (the same applies to FIGS. 9 to 11, 13, and 14 described later).

  FIG. 5 is a block diagram illustrating a functional configuration of the image acquisition device 1. The configuration surrounded by the broken line is the configuration shown in FIGS. 1 to 3, and the other configuration is realized by the computer 3. The image acquisition apparatus 1 includes a profile acquisition unit 31 to which an output from the film thickness meter 12 is input, an angle determination unit 32 to which a later-described profile obtained by the profile acquisition unit 31 is input, and an overall control unit that controls the whole. 30, the display control part 33 into which the output from the light-receiving part 23 is input, and the display 34 which is a display part are provided.

  FIG. 6 is a flowchart of the operation of the image acquisition apparatus 1. In the image acquisition device 1, first, the movement mechanism 11 is controlled so that the region where the pattern exists on the glass substrate 9 is located below the film thickness meter 12 (that is, the position indicated by the two-dot chain line in FIG. 1). The thickness of each layer is acquired by the thickness meter 12. Further, by controlling the moving mechanism 11, a background region, which is a region around the pattern, is arranged below the film thickness meter 12, and the film thickness of each layer is also acquired in the background region (step S11). . In addition, the film thickness of each layer may be acquired only in the region where the pattern exists, and the film thickness of each layer in the background may be estimated from these film thicknesses.

  The film thickness measurement result is input to the profile acquisition unit 31. In the profile acquisition unit 31, a profile indicating the relationship between the (irradiation angle) and the detection angle and contrast is obtained by calculation based on the layer structure on the substrate and the film thickness of each layer (step S12). FIG. 7 is a diagram illustrating an acquired profile. A solid line 811 shows the relationship between the detection angle and the contrast when a 900 nm thick transparent film is formed on a 30 nm thick transparent electrode pattern. In the background, it is assumed that only a transparent film having a thickness of 900 nm exists. The wavelength of irradiation light is 570 nm. As will be described later, in acquiring an image in the imaging unit 2, the light irradiation unit rotation mechanism 22 and the light receiving unit rotation mechanism 24 are controlled so that the irradiation angle θ1 and the detection angle θ2 coincide. Therefore, the size of the detection angle in the description of the profile is also the size of the irradiation angle, and the size of the irradiation angle is also the size of the detection angle.

  Here, contrast refers to the intensity of light incident on the light receiving unit 23 when a multilayer film including a pattern is present on the base material, and the case where only the film obtained by removing the pattern from the multilayer film is present on the base material. It is a ratio with the intensity | strength of the light which injects into the light-receiving part 23. In other words, the contrast is the lightness ratio between the pattern and the background (= (lightness of the pattern area) / (lightness of the background area)). The brightness corresponds to the reflectance at that wavelength, and the brightness ratio is also the reflectance ratio. Of course, other values such as a difference in brightness and reflectance may be used as the contrast.

  In FIG. 7, normally, good pattern display is possible when the contrast is 0.5 or less or 2 or more. In the case of the solid line 811, an appropriate pattern image is acquired when the detection angle is approximately 0 ° to 28 °, or 40 ° to 45 °. However, 45 ° is only a formal upper limit in FIG. If the contrast is 0.77 or less or 1.3 or more, pattern observation is possible depending on conditions. Preferably, the contrast is 0.67 or less or 1.5 or more. Further, “high contrast” means that the contrast is good, and means that the light and dark can be clearly distinguished. High contrast does not necessarily mean that the contrast value is large.

  The broken line 812 in FIG. 7 shows the relationship between the detection angle and contrast when a 960 nm thick transparent film is formed on a 30 nm thick transparent electrode pattern. In the background, it is assumed that only a transparent film having a thickness of 960 nm exists. An alternate long and short dash line 813 indicates a relationship between a detection angle and contrast when a transparent film having a thickness of 1000 nm is formed on a transparent electrode pattern having a thickness of 30 nm. In the background, it is assumed that only a transparent film having a thickness of 1000 nm exists. The wavelength of irradiation light is 570 nm. As shown by the curves 811 to 813, it can be seen that the detection angle at which a pattern image with high contrast is acquired greatly changes as the thickness of the transparent film changes.

  That is, when the detection angle is changed, the optical path length of the light passing through each transparent layer is changed and the interference state of the light is changed, so that even if a high contrast cannot be obtained at a specific detection angle, High contrast can be obtained by changing the detection angle without changing the wavelength. In other words, by changing the detection angle, image acquisition equivalent to acquiring a pattern image by selecting a wavelength from a number of wavelengths using a white light source and a number of filters is realized.

  The angle determination unit 32 determines an angle (hereinafter referred to as “set angle”) for setting the irradiation angle and the detection angle based on the acquired profile (step S13). In determining the set angle, the movable range of the light irradiation unit 21 and the light receiving unit 23 and other conditions are taken into consideration. The set angle is input to the overall control unit 30, and an operation related to the angle adjustment is performed (step S14).

  FIG. 8 is a diagram showing the flow of operations related to angle adjustment, and shows the processing performed in step S14 of FIG. In the operation related to the angle adjustment, first, the light receiving unit rotating mechanism 24 (see FIG. 2) rotates the light receiving unit 23, whereby the detection angle θ2 is changed to become a set angle (step S141). In FIG. 9, the light receiving unit 23 before the change in the detection angle θ2 is indicated by a two-dot chain line, and the light receiving unit 23 after the change in the detection angle θ2 is indicated by a solid line.

  Subsequently, the light irradiation unit rotating mechanism 22 rotates the light irradiation unit 21 based on the amount of displacement γ of the detection angle θ2 in the light receiving unit 23 (that is, the angle difference before and after the change of the detection angle θ2). The angle θ1 is changed to become a set angle (step S142). In FIG. 10, the light irradiation part 21 before rotation is shown by a two-dot chain line, and the light irradiation part 21 after rotation is shown by a solid line. When the irradiation angle θ1 and the detection angle θ2 are equal immediately before the operation related to the angle adjustment, the displacement amount of the irradiation angle θ1 is twice the displacement amount γ of the detection angle θ2, and the rotation direction of the light irradiation unit 21 is The direction of rotation of the light receiving unit 23 is opposite.

  In parallel with the above operation, in the overall control unit 30, the position at which the optical axis J2 of the light receiving unit 23 before the change of the detection angle θ2 and the thin film pattern of the glass substrate 9 (that is, the surface of the glass substrate 9) intersect (FIG. 9). The distance between the optical axis J2 after the change of the detection angle θ2 and the position R2 where the thin film pattern intersects (in FIG. 9). Is a distance indicated by an arrow with a symbol D in FIG. 5 and is hereinafter referred to as a “positional deviation amount”) based on the displacement amount γ of the detection angle θ2 (step S143). Then, the glass substrate 9 is moved relative to the imaging region 90 by the displacement amount D in the direction from the target position R1 to the position R2 by the moving mechanism 11 (step S144). Thereby, as shown in FIG. 10, the optical axis J2 after the change of the detection angle θ2 and the target position R1 on the glass substrate 9 intersect.

  In the overall control unit 30, the distance between the position where the optical axis J2 and the surface of the glass substrate 9 intersect and the focus position P (hereinafter referred to as “focus adjustment distance”) is the amount of displacement of the detection angle θ2. Obtained based on γ (step S145). Then, by moving the light receiving unit 23 by the focus adjustment distance along the optical axis J2 by the light receiving unit moving mechanism 25, as shown in FIG. 11, the focus position conjugate with the light receiving surface of the line sensor 231 on the optical axis J2. P is arranged on the thin film pattern at the target position R1 (that is, focus adjustment is performed) (step S146). By the operation related to the angle adjustment described above, the irradiation angle θ1 and the detection angle θ2 become the set angles, the imaging region 90 becomes the same position as before the change of the detection angle θ2 with respect to the glass substrate 9, and the focus adjustment of the light receiving unit 23 is also completed. To do.

  Note that the change of the detection angle θ2 in step S141, the rotation of the light irradiation unit 21 in step S142, the movement of the glass substrate 9 in step S144, and the movement of the light receiving unit 23 in step S146 are performed approximately in parallel. Also good. Further, in the focus adjustment in which the focus position P is arranged on the thin film pattern, an autofocus operation may be performed. In the autofocus operation, for example, a plurality of positions (including positions indicated by the focus adjustment distance) sequentially separated by a predetermined minute distance around the position indicated by the focus adjustment distance obtained in step S145 in the optical axis J2 direction. ) Are arranged in each of them, and a line image is acquired by the line sensor 231. Of the plurality of positions, the position where the amount of change (differential value) of the pixel value at the edge of the portion corresponding to the thin film pattern in the cross-sectional profile indicated by the line image is maximized (that is, the position where the contrast is highest). The light receiving unit 23 is disposed on the surface. The cross-sectional profile is preferably displayed on the display 34 of the computer 3.

  Further, in the operation related to the angle adjustment, fine adjustment of the angular position of the light irradiation unit 21 may be performed. For example, the light irradiation unit 21 is arranged at each of a plurality of angular positions that are sequentially separated by a predetermined minute angle clockwise and counterclockwise from the angular position of the light irradiation unit 21 after the irradiation angle θ1 is changed, and the line sensor In step S231, a line image is acquired. Of the plurality of angular positions, the light irradiation unit 21 is disposed at an angular position where the amount of change in the pixel value at the edge of the portion corresponding to the thin film pattern is maximized in the cross-sectional profile indicated by the line image. In this case, the autofocus operation may be further performed.

  Furthermore, each operation related to the angle adjustment may be performed at a timing instructed by the operator. For example, by selecting a stage movement button by clicking the mouse on the window displayed on the display 34, the glass substrate 9 is moved in step S144, and the optical axis J2 of the light receiving unit 23 and the surface of the glass substrate 9 are moved. May be matched before and after the change of the detection angle θ2. Similarly, the autofocus operation may be performed by selecting an autofocus button in the window.

  When the operation related to the angle adjustment is completed as described above (FIG. 6: Step S14), emission of light from the light irradiation unit 21 is started, and the glass substrate 9 is continuously moved in the Y direction by the moving mechanism 11. . In parallel with the movement of the glass substrate 9, the line sensor 231 of the light receiving unit 23 repeatedly acquires a line image of the linear imaging region 90 at a high speed (step S15). The line image data is input to the display control unit 33, whereby data of a two-dimensional pattern image indicating a thin film pattern is acquired (that is, stored), and the pattern image is displayed on the display 34 of the computer 3 ( Step S16).

  As described above, the image of the transparent thin film pattern formed by the transparent electrode film is displayed (visualized) based on the output from the light receiving unit 23, so that the operator can determine the shape of the thin film pattern. It can be confirmed, and the process of forming the thin film pattern can be improved. Further, in the image acquisition device 1, in the pattern image displayed on the display 34, by selecting any two points with the input unit, the distance between the two points is displayed (or output). Furthermore, a cross-sectional profile at an arbitrary position can be displayed based on pattern image data, and a distance between any two points in the cross-sectional profile can also be displayed.

  Here, if focus adjustment is performed by moving the large glass substrate 9 up and down in the Z direction, a large lifting mechanism is required. On the other hand, in the image acquisition device 1, the light receiving unit moving mechanism 25 moves the light receiving unit 23 along the optical axis J2 based on the amount of displacement of the detection angle by the light receiving unit rotating mechanism 24, thereby causing the optical axis J2 to move. Above, a focus position P conjugate with the light receiving surface of the line sensor 231 is arranged on the thin film pattern. Thereby, the focus adjustment of the light receiving unit 23 can be easily performed while changing the detection angle.

  In the imaging unit 2, the irradiation angle can be easily set to the detection angle by providing the light irradiation unit rotating mechanism 22 that rotates the light irradiation unit 21 around the axis parallel to the imaging region 90 and passing through the focus position P. Can match. Further, the overall control unit 30 controls the moving mechanism 11 based on the displacement amount of the detection angle, so that the position of the imaging region 90 with respect to the glass substrate 9 matches before and after the change of the detection angle. Thereby, it is possible to prevent the position of the imaging region 90 relative to the glass substrate 9 from being shifted due to the change of the detection angle.As a result, when acquiring a pattern image in which the detection angle and the irradiation angle are changed in a plurality of ways, etc. It is possible to easily acquire an image of the same region on the glass substrate 9.

  The image acquisition device 1 can acquire and display a pattern image having a high contrast between the pattern and the background without changing the wavelength of light applied to the imaging region 90. This eliminates the need for a complicated structure for changing the wavelength, or the design and complicated adjustment of an optical system corresponding to multi-wavelength light, and the manufacturing cost of the image acquisition device 1 can be reduced. Further, for example, even when a photosensitive resist is included in the layer on the pattern, it is possible to easily display the pattern image while avoiding light having an unusable wavelength.

  In the image acquisition device 1, in addition to displaying the pattern image, a pattern inspection may be performed. For example, the inspection unit 36 is connected to the light receiving unit 23 as indicated by a broken-line rectangle in FIG. In the pattern inspection, the line image is repeatedly output from the light receiving unit 23 to the inspection unit 36 in synchronization with the movement of the glass substrate 9, and pattern image data is acquired. The inspection unit 36 stores reference image data serving as a reference, and the presence or absence of a defect is determined by comparing the pattern image data with the reference image data. In addition, when using the image acquisition apparatus 1 as a pattern inspection apparatus, since a pattern image is acquired continuously, the sensor which detects the distance between the light-receiving part 23 and the glass substrate 9 in the optical axis J2 direction, for example , And the light receiving unit 23 may move along the optical axis J2 based on the output of the sensor, so that focus adjustment may be performed in real time when the pattern image is acquired. Further, the inspection unit 36 may be provided in another image acquisition device.

  In the image acquisition device 1, as shown in FIG. 12, the plurality of imaging units 2 are arranged in a staggered manner along the X direction, so that the glass substrate 9 is moved in the Y direction once. A pattern image in the entire width may be acquired. Each imaging unit 2 has the same configuration as the imaging unit 2 of FIGS. 2 and 3 except that the support block 201 is fixed to a separately provided top plate. In the image acquisition device 1 of FIG. 12, the focus adjustment of the light receiving units 23 in the plurality of imaging units 2 can be individually performed, and it easily copes with the undulation of the glass substrate 9 and the inclination of the glass substrate 9 on the stage 41. Thus, the pattern image can be obtained with high accuracy in each imaging unit 2. A plurality of imaging units 2 may be provided in other image acquisition devices.

  FIG. 13 is a diagram illustrating another example of the light irradiation unit. In the imaging unit 2 having the light irradiation unit 21a of FIG. 13, the light irradiation unit rotation mechanism 22 is omitted. In the light irradiation unit 21 a, an arcuate support unit 210 centering on an axis parallel to the linear imaging region 90 and passing through the focus position P is provided, and the support unit 210 is fixed to the light receiving unit 23. A plurality of LEDs 211 are arranged on the support unit 210, and light from the plurality of LEDs 211 is made uniform through the diffusion plate 212 and irradiated onto the imaging region 90. As described above, the light irradiation unit 21a shown in FIG. 13 irradiates the imaging region 90 with light in a predetermined angle range α around the axis parallel to the imaging region 90 and passing through the focus position P.

  In the imaging unit 2 having the light irradiation part 21a, on the surface perpendicular to the axis, an angular position (inclined by the detection angle θ2 from the normal line N of the glass substrate 9 to the side opposite to the optical axis J2 with the axis as the center ( As long as the angle range α is included in the angle range α, it is assumed that the optical axis from the light irradiation unit 21a to the imaging region 90 is disposed at the angular position. The irradiation angle is equal to the detection angle. Therefore, the image acquisition device 1 having the light irradiation unit 21a can easily acquire a pattern image with high contrast. Further, since the mechanism for rotating the light irradiation unit 21 is omitted, the control of the imaging unit can be simplified. The light irradiation unit 21a of FIG. 13 may be used in another image acquisition device.

  FIG. 14 is a diagram illustrating another example of the image acquisition apparatus. The image acquisition apparatus 1a of FIG. 14 includes a transport mechanism 11a, a film thickness meter 12, an imaging unit 2, and a computer 3, except that the structure of the transport mechanism 11a is different from the moving mechanism 11 of FIG. This is the same as the image acquisition device 1 in FIG. The display object is a web of a resin film on which a transparent electrode film or a transparent film is formed, that is, a continuous sheet.

  The transport mechanism 11a includes a supply unit 111 located on the right side ((+ Y) side) of FIG. 14 and a recovery unit 112 located on the left side ((−Y) side). The supply unit 111 supports the web 9a as a roll 91 and feeds the web 9a leftward. The collection unit 112 supports the web 9a as a roll 92 and collects the web 9a. The transport mechanism 11a is a moving mechanism that moves the base material, which is the main part of the web 9a, relative to the imaging region 90. In the image acquisition device 1a of FIG. 14, the imaging region 90 is provided over almost the entire width of the web 9a. However, the length of the imaging region 90 is made smaller than the width of the web 9a, and the imaging unit 2 is moved in the X direction. A moving mechanism may be provided separately. The film thickness meter 12 and the imaging unit 2 are arranged in this order from the supply unit 111 toward the collection unit 112. The operation of acquiring the pattern image in the image acquisition device 1a is the same as that of the image acquisition device 1 in FIG.

  Also in the image acquisition device 1a, the light receiving unit moving mechanism 25 moves the light receiving unit 23 along the optical axis J2, so that the focus position P is arranged on the surface of the web 9a. Thereby, the focus adjustment of the light receiving unit 23 can be easily performed while changing the detection angle. In addition, since a mechanism for switching the wavelength of the light source is unnecessary, the manufacturing cost of the image acquisition device 1a can be reduced.

  In the image acquisition devices 1 and 1a described above, the detection angle changing mechanism that changes the detection angle is realized by the light receiving unit rotating mechanism 24 that rotates the light receiving unit 23. The detection angle changing mechanism inclines the base material. It may be realized by a mechanism.

  For example, in the image acquisition device 1b of FIG. 15, the (−Y) side end of the second moving unit 43 in the moving mechanism 11 is supported by the support unit 45 so as to be rotatable about an axis parallel to the X direction. The Then, when the sliding part moving mechanism 44 moves the sliding part 441 in contact with the bottom surface of the second moving part 43 in the Y direction, the glass substrate 9 rotates around the support part 45 together with the moving mechanism 11. The detection angle formed by the optical axis J2 of the light receiving unit 23 and the normal line N of the glass substrate 9 is changed. As described above, in the image acquisition device 1b of FIG. 15, the detection angle changing mechanism is realized by the sliding portion moving mechanism 44 (and the support portion 45), and the light receiving portion rotating mechanism 24 of FIG. 1 is omitted. Further, the light receiving portion 23 is moved along the optical axis J2 by the light receiving portion moving mechanism 25 (that is, in the Z direction), whereby the focus position P is disposed on the surface of the glass substrate 9. And a pattern image is acquired because the 2nd moving part 43 moves the glass substrate 9. FIG.

  In the image acquisition device 1c of FIG. 16, a roller 461 extending in the X direction is provided between the supply unit 111 and the imaging unit 2 in the Y direction, and the X direction is provided between the light receiving unit 23 and the collection unit 112. Another roller 462 is provided that extends to the front. The roller 461 can be moved in the Z direction by the roller lifting mechanism 46, and the direction of the normal line N of the web 9a in the vicinity of the lower part of the imaging unit 2 is changed by changing the position of the roller 461 in the Z direction. The In the image acquisition device 1c of FIG. 16, a detection angle changing mechanism that changes the detection angle formed by the optical axis J2 of the light receiving unit 23 and the normal line N of the web 9a is realized by the roller lifting mechanism 46 (and the roller 461). The light receiving unit rotating mechanism 24 in FIG. 1 is omitted. Further, the light receiving portion 23 is moved along the optical axis J2 (that is, in the Z direction) by the light receiving portion moving mechanism 25, whereby the focus position P is disposed on the surface of the web 9a. And a pattern image is acquired because the conveyance mechanism 11a moves the web 9a.

  Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications can be made.

  In the image acquisition device 1, the irradiation angle and the detection angle are changed to a plurality of angles while keeping the irradiation angle and the detection angle equal, and the light intensity from the pattern region in the line image acquired by the light receiving unit 23 at each angle. A profile indicating the relationship between the detection angle and the contrast may be obtained by obtaining the ratio of the light intensity from the background region as the contrast. In this case, the film thickness meter 12 is omitted from the image acquisition device 1.

  Further, when one of p-polarized light and s-polarized light can be used to obtain a pattern image having a higher contrast than the case where polarized light is not used, the space between the imaging region 90 and the light receiving unit 23 can be obtained. A polarizer may be disposed on the substrate. In this case, only p-polarized light or s-polarized light out of the reflected light from the glass substrate 9 enters the light receiving unit 23. In addition, a rotation mechanism that rotates the polarizer around the optical axis J2 may be provided, and the polarized light incident on the light receiving unit 23 may be switched. Further, the first pattern image may be acquired based on the p-polarized light, and the second pattern image may be acquired based on the s-polarized light. In this case, for example, the product of the value of each pixel of the first pattern image and the value of the corresponding pixel of the second pattern image is obtained, and an image having the product as the pixel value is obtained as the pattern image. In such a pattern image, since two different types of images are used, the influence of noise or the like in the image is reduced.

  The display target (or inspection target) base material is not limited to a film or a glass substrate, and may be a resin plate or the like. The film structure formed on the substrate may be various, and usually has a more complicated structure than that exemplified in the above embodiment. The pattern to be displayed is not limited to one type and may be a plurality of types. In this case, at the time of displaying each display target pattern, the other pattern overlapping this pattern is treated as a background.

  In the above embodiment, the background has been described as having one type, but the background is not limited to one type. When there are a plurality of types of backgrounds, a profile is obtained for each background, and an irradiation angle and a detection angle at which the contrast is high for any background are determined.

  The composition of the thin film pattern may be formed of other materials as long as it has a certain degree of transparency to the irradiation light, and is not necessarily transparent to visible light. The pattern is not limited to the transparent electrode, and may be a pattern for other uses. However, the application of the image acquisition device is particularly suitable for displaying a pattern image of a transparent electrode that cannot be shaded even when irradiated with visible light.

  The moving mechanism that moves the base material relative to the imaging region may be a mechanism that fixes the base material and moves the imaging unit 2. The light irradiation unit rotation mechanism 22 and the light reception unit rotation mechanism 24 are not necessarily independent mechanisms, and may be a mechanism that changes the irradiation angle and the detection angle in conjunction with each other. In the light irradiation unit rotating mechanism 22 and the light receiving unit rotating mechanism 24, the irradiation angle and the detection angle do not need to change continuously, and may be changed only in several steps (sliding unit in FIG. 15). The same applies to the moving mechanism 44 and the roller lifting mechanism 46 of FIG.

  The wavelength of the light emitted from the light irradiation unit is not limited to a single wavelength, and light of a plurality of wavelengths may be selectively emitted. The light source may be provided with an LD instead of the LED. Further, a combination of a lamp such as a halogen lamp and a filter may be provided as the light source. The film thickness meter 12 may be a spectroscopic ellipsometer.

  The configurations in the above-described embodiments and modifications may be combined as appropriate as long as they do not contradict each other.

DESCRIPTION OF SYMBOLS 1,1a-1c Image acquisition apparatus 2 Imaging unit 9 Glass substrate 9a Web 11 Movement mechanism 11a Conveyance mechanism 21,21a Light irradiation part 22 Light irradiation part rotation mechanism 23 Light receiving part 24 Light reception part rotation mechanism 25 Light reception part movement mechanism 30 General control unit 44 Sliding part moving mechanism 46 Roller lifting mechanism 90 Imaging area 231 Line sensor 232 Optical system J1, J2 Optical axis P Focus position S15, S141, S144, S146 Step α Angle range γ Displacement amount θ1 Irradiation angle θ2 Detection angle

Claims (7)

An image acquisition device for acquiring an image of a thin film pattern formed on a substrate,
An imaging unit for imaging a linear imaging region on the substrate;
A moving mechanism for moving the base material relative to the imaging region in a direction intersecting the imaging region;
A control unit;
With
The imaging unit is
A light irradiation unit that emits light of a wavelength having transparency to the thin film pattern;
A light receiving unit including a line sensor and an optical system that guides light from the imaging region irradiated with the light to the line sensor;
A detection angle changing mechanism for changing a detection angle formed by an optical axis of the optical system and a normal line of the substrate;
A light receiving unit moving mechanism for moving the light receiving unit along the optical axis;
With
The control unit controls the light receiving unit moving mechanism based on the amount of displacement of the detection angle, thereby placing a position conjugate with the light receiving surface of the line sensor on the thin film pattern on the optical axis. A characteristic image acquisition device. The image acquisition device according to claim 1,
The imaging unit further includes a light irradiation unit rotation mechanism that rotates the light irradiation unit around an axis parallel to the imaging region and passing through the conjugate position,
The light irradiation unit rotation mechanism is fixed to the light receiving unit,
The control unit controls the light irradiation unit rotation mechanism on the basis of the displacement amount of the detection angle, so that the irradiation angle formed by the optical axis from the light irradiation unit to the imaging region and the normal line is set as described above. An image acquisition apparatus characterized by matching with a detection angle. The image acquisition device according to claim 1,
The light irradiation unit irradiates the light toward the imaging region in a predetermined angle range centered on an axis parallel to the imaging region and passing through the conjugate position;
The light irradiation unit is fixed to the light receiving unit,
An image acquisition characterized in that an angular position inclined by the detection angle about the axis on the opposite side of the optical axis from the normal line on a plane perpendicular to the axis is included in the predetermined angle range. apparatus. The image acquisition device according to any one of claims 1 to 3,
The control unit controls the moving mechanism based on a displacement amount of the detection angle, thereby matching the position of the imaging region with respect to the base material before and after the change of the detection angle. . The image acquisition device according to any one of claims 1 to 3,
An image acquisition apparatus, further comprising another imaging unit having a configuration similar to that of the imaging unit. An image acquisition method for acquiring an image of a thin film pattern formed on a substrate by an image acquisition device,
The image acquisition device is
A light irradiation unit that emits light of a wavelength having transparency to the thin film pattern;
A light receiving unit including a line sensor and an optical system that guides light from a linear imaging region irradiated with the light to the line sensor;
With
The image acquisition method includes:
a) changing the detection angle formed by the optical axis of the optical system and the normal of the substrate;
b) arranging the position conjugate with the light receiving surface of the line sensor on the optical axis on the thin film pattern by moving the light receiving unit along the optical axis;
c) moving the substrate relative to the imaging region in a direction intersecting the imaging region;
An image acquisition method comprising: The image acquisition method according to claim 6, wherein the c) step is performed before
d) The image acquisition further comprising the step of matching the position of the imaging region with respect to the base material before and after the change of the detection angle by moving the base material relative to the imaging region. Method.

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