JP4702952B2 - Unevenness inspection method, unevenness inspection apparatus, and program - Google Patents

Description

  The present invention relates to a technique for inspecting streak unevenness on a multi-faced substrate.

  Conventionally, when a panel pattern is formed on a main surface of a glass substrate for a display device, a resist solution is applied on the main surface to form a resist film. When a resist film is formed, for example, if a minute unnecessary object is present on the substrate immediately before the resist solution is applied, the unnecessary object is caught in the slit for discharging the resist solution, resulting in streak unevenness on the resist film. Sometimes. In recent years, by detecting the position of such streak unevenness on a substrate, the cause of streak unevenness is identified to improve the manufacturing process, the pattern to be formed, and the like.

  As an example of a technique for detecting the existence position of streak unevenness, in Patent Document 1, each pixel in an image to be inspected is sequentially set as a target pixel, and a value is obtained in a region having a predetermined size centered on the target pixel. Is calculated for each of a plurality of angle reference lines having different inclinations, and a minimum value of these sums is calculated. A technique for acquiring an image indicating the presence position of streak unevenness by using a value based on the value of the target pixel is disclosed.

In Patent Document 2, when a high-pass filter process is performed after a low-pass filter process is performed on an image obtained by imaging a substrate, a pixel group used for the high-pass filter process is included in the region to which the target pixel of the high-pass window belongs. A method for improving the accuracy of unevenness inspection in the vicinity of the edge of each region set on a multi-faced substrate by limiting the number of pixels is disclosed.
JP 2005-345290 A JP 2006-105884 A

  By the way, when a plurality of panel patterns are formed on a substrate (that is, the substrate is multi-faceted), a plurality of rectangular regions each corresponding to a display region of the panel are spaced apart from each other on the substrate. It is set by aligning vertically and horizontally. In this case, since a uniform pattern is formed in a plurality of rectangular areas, various patterns are formed in the gaps between the rectangular areas, so that an image acquired from the substrate remains as it is. When used for unevenness inspection, false alarms frequently occur in areas corresponding to gaps between rectangular areas. Therefore, in the unevenness inspection, a certain pixel value is given to an area corresponding to the gap between the rectangular areas in the image showing the substrate (that is, the area is masked), and an image to be inspected is obtained. It is preferable to be prepared. However, when performing streak unevenness inspection on such an image, if streak unevenness extending over a plurality of rectangular areas exists on the substrate, these are derived from the same streak unevenness. The plurality of streaky areas detected in the rectangular area are independent from each other, and the cause of streak unevenness cannot be identified efficiently.

  The present invention has been made in view of the above problems, and has an object to easily detect streak unevenness extending over a plurality of rectangular regions.

  According to the first aspect of the present invention, a plurality of rectangular areas having a uniform pattern are set to be vertically and horizontally aligned with a gap therebetween, and the unevenness on the substrate that is multifaceted according to the plurality of rectangular areas is inspected. A non-uniformity inspection method comprising: a) preparing a target image by masking a region corresponding to the gap in a multi-tone original image obtained by imaging the substrate; b) Identifying a plurality of closed regions in which a ratio of a length in a longitudinal direction to a width in a direction perpendicular to the longitudinal direction is a predetermined value or more in a binarized binary image as a plurality of streaky element regions, c) A step of detecting two stripe unevenness element areas that are the same in the longitudinal direction and are arranged in the longitudinal direction and are present in adjacent rectangular areas among a plurality of stripe unevenness element areas.

  The invention according to claim 2 is the unevenness inspection method according to claim 1, wherein in the step b), the stripe unevenness element region is specified by a stripe unevenness element line representing the region, and c) In the process, the stripe unevenness element line segment is treated as a corresponding stripe unevenness element region.

  Invention of Claim 3 is the nonuniformity inspection method of Claim 1 or 2, Comprising: d) The process of displaying the existing position of the connection area | region which connected the said 2 stripe nonuniformity element area | region on a display part further Prepare.

  The invention according to claim 4 is the method for inspecting unevenness according to claim 3, wherein e) before the d) step, the minimum of the length of the connecting region where the location is displayed in the d) step. The method further includes a step of receiving a value input.

  A fifth aspect of the present invention is the unevenness inspection method according to any one of the first to fourth aspects, wherein the step b) includes a plurality of streaky unevenness element regions specified in one rectangular region. The two stripe unevenness element regions that are the same in the longitudinal direction and are arranged in the longitudinal direction and close to each other are detected by the same algorithm as in the step c), and the two stripe unevenness element regions are detected as 1 A step of updating to one streak unevenness element region.

  A sixth aspect of the present invention is the unevenness inspection method according to any one of the first to fifth aspects, wherein the substrate has a film formed by applying a liquid on one main surface. .

  According to the seventh aspect of the present invention, a plurality of rectangular regions having a uniform pattern are set to be vertically and horizontally aligned with a gap therebetween, and the unevenness on the substrate that is multifaceted according to the plurality of rectangular regions is inspected. An unevenness inspection apparatus, an imaging unit that captures the substrate and acquires a multi-tone original image, and a target image generation unit that generates a target image by masking a region corresponding to the gap of the original image; In the binary image obtained by binarizing the target image, a plurality of closed regions in which the ratio of the length in the longitudinal direction to the width in the direction perpendicular to the longitudinal direction is equal to or greater than a predetermined value is specified as a plurality of streaky element regions. Among the plurality of stripe unevenness element specifying portions and the plurality of stripe unevenness element areas, two stripe unevenness element areas having the same longitudinal direction and arranged in the longitudinal direction and existing in an adjacent rectangular area are detected. To detect the unevenness of the muscle Provided.

  According to the eighth aspect of the present invention, a plurality of rectangular regions having a uniform pattern are set to be aligned vertically and horizontally with a gap, and streaks on the substrate that are multi-faced according to the plurality of rectangular regions are set in a computer. A program to be inspected by the computer executing the program by a) masking a region corresponding to the gap of the multi-tone original image obtained by imaging the substrate B) In a binary image obtained by binarizing the target image, a plurality of closed regions in which a ratio of a length in a longitudinal direction to a width in a direction perpendicular to the longitudinal direction is a predetermined value or more A step of identifying as a streak uneven element region, and c) among the plurality of streak uneven element regions, the longitudinal direction is the same, and is arranged in the longitudinal direction and exists in an adjacent rectangular region. To execute the steps of detecting two streaks element region.

  According to the present invention, it is possible to easily detect streak unevenness extending over a plurality of rectangular regions.

  Further, in the invention of claim 2, it is possible to more easily detect streak unevenness extending over a plurality of rectangular regions, and in the invention of claim 3 easily confirm streak unevenness extending over a plurality of rectangular regions. can do.

  Further, in the invention of claim 4, it is possible to easily confirm only the stripe unevenness having a length equal to or longer than the minimum value, and in the invention of claim 5, it can be derived from the same stripe unevenness in one rectangular region. A plurality of highly uneven stripe element regions can be handled as one uneven stripe element region, and subsequent processing can be performed efficiently.

  FIG. 1 is a diagram showing a configuration of an unevenness inspection apparatus 1 according to an embodiment of the present invention. The unevenness inspection apparatus 1 applies a resist solution on a main surface 91 of a glass substrate 9 used for a display device such as a liquid crystal display device by using a coating device such as a spin coat method or a slit coat method. This is an apparatus for acquiring an image of the formed resist film 92 for pattern formation and inspecting the stripe unevenness on the film 92 of the substrate 9 based on this image. Note that a plurality of panel patterns for a display device are formed on (or will be formed on) the substrate in this embodiment.

  Here, the unevenness on the substrate 9 is a region having a certain area or more specified by local fluctuations in brightness (however, the boundary of the region is usually unclear), and the unevenness of the stripe is the length of the region. The ratio (α / β) between the length α in the direction and the width β in the direction perpendicular to the longitudinal direction is defined as a predetermined value or more. Of course, as long as this condition is substantially satisfied, the definition of the stripe unevenness may be changed as appropriate, and other conditions may be added.

  As shown in FIG. 1, in the unevenness inspection apparatus 1, the substrate 9 is placed with the main surface 91 (hereinafter referred to as “upper surface 91”) on which the film 92 is formed facing upward (the (+ Z) side in FIG. 1). The stage 2 to be held, the film 92 on the substrate 9 held on the stage 2 is irradiated with light at a predetermined incident angle, and the film 92 on the upper surface 91 of the substrate 9 is irradiated from the light irradiation unit 3. The light receiving unit 4 that receives the light reflected by the light, the moving mechanism 21 that moves the stage 2 relative to the light irradiation unit 3 and the light receiving unit 4, and the control unit of the unevenness inspection apparatus 1 A computer 5 is provided.

  The (+ Z) side surface of the stage 2 is preferably black matte. The moving mechanism 21 has a configuration in which a ball screw (not shown) is connected to a motor 211, and the stage 211 moves along the upper surface 91 of the substrate 9 along the guide 212 by rotating the motor 211 in FIG. Move in the direction.

  The light irradiation unit 3 is a halogen lamp 31 that is a light source that emits white light (that is, light including light of all wavelengths in the visible region) and a circle extending in the Y direction in FIG. 1 perpendicular to the moving direction of the stage 2. A columnar quartz rod 32 and a cylindrical lens 33 extending in the Y direction are provided. In the light irradiation unit 3, a halogen lamp 31 is attached to an end portion on the (+ Y) side of the quartz rod 32, and light incident on the quartz rod 32 from the halogen lamp 31 is linear light extending in the Y direction (that is, The light beam cross-section is converted to light that is long in the Y direction), is emitted from the side surface of the quartz rod 32, and is guided to the upper surface 91 of the substrate 9 through the cylindrical lens 33. In other words, the quartz rod 32 and the cylindrical lens 33 are an optical system that converts the light from the halogen lamp 31 into linear light perpendicular to the moving direction of the stage 2 and guides it to the upper surface 91 of the substrate 9.

  In FIG. 1, the optical path from the light irradiation unit 3 to the substrate 9 is indicated by a one-dot chain line (the same applies to the optical path from the substrate 9 to the light receiving unit 4). A part of the light emitted from the light irradiation unit 3 is reflected on the (+ Z) side upper surface of the film 92 on the upper surface 91 of the substrate 9. The film 92 is light transmissive with respect to the light from the light irradiation unit 3, and the light that has not been reflected by the upper surface of the film 92 out of the light from the light irradiation unit 3 passes through the film 92. Reflected by the upper surface 91 of the substrate 9 (that is, the lower surface of the film 92). In the unevenness inspection apparatus 1, interference light between the light reflected by the upper surface of the film 92 and the light reflected by the upper surface 91 of the substrate 9 enters the light receiving unit 4 and passes through the filter 43 and the lens 42. Thus, interference light having a predetermined wavelength is guided to the imaging unit 41.

  The imaging unit 41 is provided with a line sensor having a plurality of light receiving elements (for example, CCD (Charge Coupled Device)) arranged linearly in the Y direction, and interference light from the substrate 9 is received by the line sensor. The intensity distribution of the interference light (that is, the distribution in the Y direction of the output value from each light receiving element) is acquired. Actually, the two-dimensional image of the film 92 on the substrate 9 is acquired by repeatedly acquiring the intensity distribution of the interference light by the line sensor of the imaging unit 41 as the substrate 9 moves in the X direction.

  As shown in FIG. 2, the computer 5 has a general computer system configuration in which a CPU 51 that performs various arithmetic processes, a ROM 52 that stores basic programs, and a RAM 53 that stores various information are connected to a bus line. The bus line further includes a fixed disk 54 that stores information, a display 55 that is a display unit that displays various types of information, a keyboard 56a that accepts input from an operator, and a mouse 56b (hereinafter collectively referred to as "input unit 56"). .), A reader 57 for reading information from a computer-readable recording medium 8 such as an optical disk, a magnetic disk, a magneto-optical disk, and a communication unit 58 connected to other components of the unevenness inspection apparatus 1 As appropriate, they are connected via an interface (I / F).

  The computer 5 reads the program 541 from the recording medium 8 via the reader 57 in advance and stores it in the fixed disk 54. Then, when the program 541 is copied to the RAM 53 and the CPU 51 executes arithmetic processing according to the program in the RAM 53 (that is, when the computer executes the program), the computer 5 inspects the stripe unevenness on the substrate 9. The operation as a calculation part is performed.

  FIG. 3 is a block diagram illustrating a functional configuration realized by the CPU 51, the ROM 52, the RAM 53, the fixed disk 54, and the like when the CPU 51 operates according to the program 541. In FIG. 3, the target image generation unit 61, the binary image acquisition unit 62, the stripe unevenness element specifying unit 63, the stripe unevenness detection unit 64, and the display control unit 65 in the calculation unit 6 show functions realized by the CPU 51 and the like. Note that these functions may be realized by a dedicated electrical circuit, or a dedicated electrical circuit may be partially used.

  Next, the flow of inspection for streaks by the unevenness inspection apparatus 1 will be described. FIG. 4 is a diagram illustrating a flow of processing in which the unevenness inspection apparatus 1 inspects streaks on the film 92 of the substrate 9. When the streak unevenness on the substrate 9 is inspected, first, the substrate 9 is held on the stage 2 positioned at the inspection start position indicated by the solid line in FIG. 1, and then in the (+ X) direction of the stage 2. The movement starts. Subsequently, linear light emitted from the light irradiation unit 3 and incident on the upper surface 91 of the substrate 9 at a predetermined incident angle is converted into a linear irradiation region on the upper surface 91 (hereinafter referred to as “linear irradiation region”). The linear irradiation area moves relative to the substrate 9. The light from the light irradiation unit 3 is reflected by the upper surface 91 of the substrate 9, the interference light is guided to the imaging unit 41 and received by the line sensor, and the intensity distribution of the interference light in the linear irradiation region on the substrate 9. Is acquired. The output from each light receiving element of the line sensor is sent to the computer 5 while being converted into a value (pixel value) of, for example, 8 bits (of course, other than 8 bits) based on a predetermined conversion formula.

  In the unevenness inspection apparatus 1, while the stage 2 is moving in the (+ X) direction, the acquisition of the interference light intensity distribution in the imaging unit 41 and the output of the pixel value to the computer 5 are synchronized with the movement of the stage 2. Repeated. When the stage 2 moves to the inspection end position, the movement of the stage 2 by the moving mechanism 21 is stopped, and irradiation of illumination light is also stopped. As described above, the imaging unit 41 captures the entire film 92 on the substrate 9 and captures a multi-gradation two-dimensional image (an image before being subjected to processing to be described later, hereinafter referred to as an “original image”). .) Is acquired and input to the calculation unit 6 of the computer 5 (step S11).

Subsequently, in the target image generation unit 61 of the calculation unit 6, the original image is compressed and the first image is generated. Here, in the original image coordinates (X, Y) pixel values of pixels positioned expressed as F _XY, the first image generated by compressing the original image in units of range of s _a pixel × s _a pixel , The pixel value A _xy of the pixel of interest located at the coordinates (x, y) is obtained by _Equation 1.

Since in this embodiment s _a is 4 (pixels), S / N ratio of the first image by the computation of the number 1 is improved to four times the original image. When the first image (original image after compression) is generated, a low-pass filter process is performed on the first image, and a second image smoothed by suppressing the influence of high-frequency noise is generated from the first image. . The window for determining the calculation range of the low-pass filter processing is a square whose length of one side is (2s ₁ +1) pixels, and the pixel value L _xy of the pixel of interest located at the coordinates (x, y) in the second image is , Using the pixel value A (see Equation 1) in the first image of each pixel in the vicinity of the pixel of interest.

Thereafter, a high-pass filter process is performed on the second image to generate a third image in which low-frequency density fluctuations that hinder the later-described contrast enhancement process are removed from the second image. Here, the pixel value H ¹ _xy of the target pixel located at the coordinates (x, y) is obtained by _Expression 3 using the pixel value L (see Expression 2) in the second image of each pixel near the target pixel. It is done.

Equation 3 shows a case where a square window having a length of (2s ₂ +1) pixels centered on the target pixel is used as a window for determining the calculation range of the high-pass filter processing. As described above, the target image generation unit 61 performs the low-pass filter process on the first image obtained by compressing the original image, and then performs the high-pass filter process, thereby performing the band-pass filter process in a predetermined spatial frequency band. Is performed (step S12).

In the target image generation unit 61, a contrast enhancement process is further performed on the third image to generate an enhanced image (step S13). The pixel value E _xy of the pixel of interest located at the coordinates (x, y) in the enhanced image is expressed by the following equation 4 using the pixel value H ¹ _xy of the pixel of interest in the third image, the contrast coefficient r _c , and the background value b. Is required. In this embodiment, _{r c} is the 0.01,0.02,0.05 or 0.1, b is a 127.

  Here, a plurality of rectangular areas (hereinafter referred to as “rectangular display areas”) each corresponding to a display area on the panel of the display device and having a uniform pattern are spaced on the upper surface 91 of the substrate 9. The substrate 9 is to be multi-faced according to a plurality of rectangular display areas (that is, to be cut into a plurality of portions (panels)). As shown in FIG. 5, the target image generation unit 61 assigns a background value b to an area corresponding to a portion outside the rectangular display area on the substrate 9 (hereinafter referred to as “background area”) in the enhanced image. , A new image in which the background region 719 (shown with parallel diagonal lines in FIG. 5) is substantially masked (as will be described later, this is an image to be subjected to the following processing in the calculation unit 6). , Hereinafter referred to as “target image”) 71 is generated and prepared (step S14). In FIG. 5, the multi-tone target image 71 is shown in a simplified manner. In practice, the boundary between the rectangular display area 711 and the background area 719 in FIG. 5 is not always clear. Further, the average density (that is, the average value of the pixel values) of the target image 71 is about 127.

  When the target image 71 is generated by the target image generation unit 61, the binary image acquisition unit 62 binarizes the target image using each of the values 103 to 122 smaller than the background value 127 as a threshold value. Specifically, the value of each pixel of the target image is compared with each threshold value (hereinafter referred to as “lower threshold value”), and “1” is assigned to a pixel whose value is equal to or lower than the lower threshold value, which is larger than the lower threshold value. By assigning “0” to the pixel, 20 binary images respectively corresponding to the lower threshold values 103 to 122 are acquired.

  FIG. A thru | or FIG. C is a diagram showing a binary image, and FIG. A shows a binary image when the lower threshold is 117, and FIG. B shows a binary image when the lower threshold is 112, and FIG. C shows a binary image when the lower threshold is 103. In the above process of acquiring a binary image using a value smaller than the background value as the lower threshold, FIG. A thru | or FIG. As shown in C, the number of pixels of value 1 (white pixels in FIGS. 6.A to 6.C) in the binary image decreases as the lower threshold value decreases (away from the background value 127).

  Subsequently, in the binary image acquisition unit 62, each of the values 132 to 151 larger than the background value 127 is set as a threshold value (hereinafter referred to as “upper threshold value”), and “1” is set to a pixel whose value is equal to or higher than the upper threshold value in the target image. ”And“ 0 ”to pixels smaller than the upper threshold value, 20 binary images respectively corresponding to the values 132 to 151 are acquired. In the above process of acquiring a binary image using a value larger than the background value as the upper threshold value, the number of pixels of value 1 in the binary image decreases as the upper threshold value increases (away from the background value 127).

  As described above, the binary image acquisition unit 62 binarizes the target image 71 with a plurality of threshold values, thereby providing a plurality of (in the present embodiment, 40) binary values respectively corresponding to the plurality of threshold values. An image is acquired (step S15). Note that, regardless of which of the lower threshold value and the upper threshold value is used, the area corresponding to the background area in the acquired binary image has a value of 0.

  When a plurality of binary images are acquired, the streak region specifying unit 631 of the streak unevenness element specifying unit 63 collects a set of pixels of value 1 that are continuous with each other by labeling in each binary image (hereinafter referred to as “closed region”). ) Is specified, and a closed region having a predetermined area (number of pixels) or less is excluded from the processing target and deleted from the binary image. Subsequently, the direction (angle) of the inertia main axis is obtained by calculating the moment of each closed region, and a circumscribed rectangle along the direction of the inertia main shaft is obtained for this closed region. Normally, the direction of the inertial main axis is the longitudinal direction of the closed region. In the following description, it is assumed that the inertia main axis is along the longitudinal direction of the closed region.

  FIG. 7 is a diagram illustrating a plurality of closed regions 721a, 721b, and 721c in the binary image. In FIG. 7, the circumscribed rectangles of the closed regions 721a to 721c are denoted by thin lines with reference numerals 722a to 722c. In the muscle region specifying unit 631, the ratio (L1 / W1) between the length L1 in the direction of the inertial main axis and the width W1 in the direction perpendicular to the inertial main axis in the circumscribed rectangles 722a to 722c of the closed regions 721a to 721c. Only the closed regions 721a and 721b, which are compared with a predetermined value (for example, 2) and the ratio is equal to or greater than the predetermined value, are defined as muscle regions (hereinafter, the same signs as the closed regions 721a and 721b), and other closed regions 721c. Are deleted from the binary image.

  As described above, the muscle region specifying unit 631 calculates the moment of the closed region in each of the plurality of binary images, so that the ratio of the length in the longitudinal direction to the width in the direction perpendicular to the longitudinal direction is greater than or equal to a predetermined value. A muscle area to be identified is specified (step S16). Note that the closed region in the binary image becomes larger when the lower threshold value or the upper threshold value approaches the background value. Therefore, even if the streak region is detected in the binary image with a certain lower threshold value or the upper threshold value, the lower threshold value close to the background value. Alternatively, in the upper threshold binary image, a closed region with a small aspect ratio may appear at the same position, and a muscle region is not always detected. In each of the muscle regions 721a and 721b, a line segment that extends in the direction of the principal axis of inertia through the center of gravity 723a and 723b and whose both end points are set on the sides of the circumscribed rectangles 722a and 722b (in FIG. Are identified as muscle region line segments 724a and 724b representing the muscle regions 721a and 721b.

  Subsequently, in the streak region update unit 632 of the streak unevenness element specifying unit 63, a plurality of regions corresponding to a plurality of rectangular display regions 711 (see FIG. 5) on the substrate 9 in each binary image (hereinafter, “rectangular” is similarly described. Focusing on one rectangular display area (hereinafter referred to as “target rectangle display area”) of any of the plurality of muscle area line segments included in the target rectangle display area Is determined as a specific muscle region line segment. Then, between the specific muscle region line segment and each of the other muscle region line segments in the target rectangular display region, it is determined whether or not these muscle region line segments can be connected.

  FIG. 8 is a diagram for explaining the determination as to whether or not the muscle region line segments can be connected. In FIG. 8, the muscle region line segments 724a and 724b in FIG. . When determining whether or not the muscle region line segment 724a is connected to the muscle region line segment 724b using the muscle region line segment 724a as the specific muscle region line segment, first, the center of gravity 723a of the muscle region 721a represented by the specific muscle region line segment 724a is used. (It may be the midpoint of the line segment line segment. The same applies hereinafter.) And the straight line connecting the center of gravity 723b of the line area 721b represented by the line segment line 724b (indicated by the broken line labeled R1 in FIG. 8) Is required). Subsequently, distances D1 and D2 between the end points 725a and 726a of the specific muscle region line segment 724a and the straight line R1, and distances D3 and D4 between the end points 725b and 726b of the muscle region line segment 724b and the straight line R1 ( That is, it is confirmed whether or not all of the lengths of the perpendicular lines (downward from the end points 725a, 726a, 725b, and 726b to the straight line R1) are equal to or less than a predetermined first threshold value.

  When any of the distances D1 to D4 is larger than the first threshold, the connection of the muscle region line segment is rejected. When all of the distances D1 to D4 are equal to or smaller than the first threshold value, the direction in which the specific muscle region line segment 724a extends (the longitudinal direction of the muscle region 721a indicated by the specific muscle region line segment 724a is described below. And the longitudinal direction of the muscle region line segment 724b are substantially the same (see FIG. 7), and then the closest between the specific muscle region line segment 724a and the muscle region line segment 724b. The sum of the distance D5 between the end points 726a and 725b and the length of the specific muscle region line segment 724a and the muscle region line segment 724b is obtained.

  When the ratio between the distance D5 and the sum of the lengths is greater than the predetermined second threshold, the connection of the muscle region line segment is rejected. When the ratio is equal to or less than the predetermined second threshold value, the specific muscle region line segment 724a and the muscle region line segment 724b are assumed to be close to each other, and further, the specific muscle region line segment 724a and the muscle region line segment are determined. A ratio between the distance D6 between the end points 725a and 726b farthest from the 724b and the sum of the lengths of the specific muscle region line segment 724a and the muscle region line segment 724b is obtained. When the ratio is equal to or greater than the predetermined third threshold value, the specific muscle region line segment 724a and the muscle region line segment 724b are assumed to be arranged in the same longitudinal direction, and the connection is permitted. If it is less than the threshold value, the connection of the muscle region line segment is rejected.

  Subsequently, the specific muscle region line segment 724a and the muscle region line segment 724b that are permitted to be connected are connected. Specifically, the moments of a set of two dividing line segments obtained by dividing the specific muscle region line segment 724a at its midpoint and two dividing line segments obtained by dividing the muscle region line segment 724b at its midpoint are expressed as follows. By calculating, the direction of the inertia main axis with respect to the set of four dividing line segments is obtained, and a straight line extending in the direction of the inertia main axis and passing through the center of gravity of the set of four dividing line segments (that is, the inertia main axis) is shown in FIG. It is calculated | required as shown with the broken line (however, a part of broken line is thickened) which attach | subjects the code | symbol R2. Then, the intersection of the perpendicular line drawn from the end points 725a, 726a, 725b, and 726b of the specific muscle region line segment 724a and the muscle region line segment 724b to the straight line R2 and the straight line R2 is obtained, and the farthest among the four intersecting points is obtained. A line segment having the intersection points 727a and 727b as end points is acquired as a new muscle area line segment (a thick broken line portion of the straight line R2 indicated by a broken line in FIG. 9), and two muscle area line segments 724a and 724b are obtained. Is updated to one line segment.

  Actually, after all the muscle region line segments that are permitted to be connected to the specific muscle region line segment 724a are determined, the specific muscle region line segment 724a and these muscle region line segments are simultaneously connected. . That is, a plurality of dividing line segments are obtained by dividing each of the specific muscle area line segments 724a and the plurality of muscle area line segments permitted to be connected at the midpoint thereof, and inertia with respect to a set of these dividing line segments. The principal axis is obtained, and the two farthest intersections of the specific principal line segment 724a and a plurality of intersections of the perpendicular to the principal axis of inertia from the end points of the plurality of muscle line segments permitted to be connected and the principal principal axis are end points. Are determined as a new muscle region line segment, and the specific muscle region line segment 724a and a plurality of muscle region line segments permitted to be connected are updated to one muscle region line segment.

  When it is determined whether or not the specific muscle region line segment 724a can be connected to another muscle region line segment and the connection is performed, the muscle region line segment updated from the specific muscle region line segment 724a in the target rectangular display region (the connection is established). If not, one muscle region line segment other than the specific muscle region line segment 724a) is specified as the specific muscle region line segment, and whether or not it can be connected to another muscle region line segment is determined and connected. . Actually, in each of the plurality of binary images, the above processing is performed with each rectangular display area as the target rectangular display area, so that the longitudinal direction of the plurality of muscle area line segments specified in each rectangular display area Are the same, are arranged in the longitudinal direction, and a plurality of adjacent muscle region line segments are updated to one muscle region line segment (step S17).

  Subsequently, in the region group acquisition unit 633 of the streak unevenness element specifying unit 63, one of the binary values in the two binary images adjacent to each other in the binarization (in the present embodiment, the thresholds are continuous) is used. It is determined whether each line segment in the image can be grouped with each line segment in the rectangular display area in the other binary image corresponding to the rectangular display area including the line segment. The

  FIG. 10 is a diagram in which muscle region line segments 724d and 724e included in two binary images adjacent to each other in the threshold value in binarization are overlapped. When determining whether or not the two muscle region line segments 724d and 724e can be grouped, first, a straight line R3 obtained by extending one of the muscle region line segments 724d (however, a portion extending from the muscle region line segment 724d is indicated by a broken line). And the distances D7 and D8 between the two end points 725e and 726e of the other line segment 724e and the straight line R3 are obtained. When both of the distances D7 and D8 are equal to or smaller than a predetermined threshold value, each line segment 724d and 724e is parallel to the pixel arrangement direction (x direction and y direction in FIG. 10) orthogonal to each other. If circumscribed rectangles 727d and 727e having sides are obtained and these circumscribed rectangles 727d and 727e overlap each other at least partially, grouping of the line segment segments 724d and 724e is permitted and included in the same group. . On the other hand, when the distance between the straight line obtained by extending one line segment and the both end points of the other line segment is longer than the threshold, the circumscribed rectangles of the two line segments do not overlap each other In some cases, these muscle line segments are not grouped.

  In this way, grouping is performed in which the muscle segment line segments that are considered to overlap each other between each binary image and another binary image whose threshold value is adjacent are included in the same group, and the muscle region lines that are not grouped. Minutes are deleted. As a result, a plurality of groups each indicating an element of streak unevenness is obtained (step S18). The above processing in the region group acquisition unit 633 is equivalent to specifying these muscle regions as a group when the positions of the muscle regions which are closed regions having predetermined flatness in the binary images having adjacent threshold values overlap each other. Therefore, in the following description, a set of grouped muscle region line segments is referred to as a region group.

  In the present embodiment, when a binary image is generated, a closed region whose value is separated from the background value is specified using the upper threshold and the lower threshold, but the binary derived using the upper threshold is used. Between the image and the binary image derived using the lower threshold, the type of the muscle region in the image is different, and the grouping of the muscle region line segment is not performed. Of course, the grouping of the muscle region line segments in the region group acquisition unit 633 may be performed by other methods.

  Further, in the streak unevenness element specifying unit 63, the longest line segment among a plurality of streak region line segments included in the region group is specified as a streak unevenness element line segment representing the region group, and a binary value corresponding to the streak unevenness element line segment is specified. The streak region in the image is a streak unevenness element region. In the following description, an area in the target image corresponding to each stripe unevenness element area (hereinafter, also referred to as “a stripe unevenness element area”) is specified by a stripe unevenness element line segment.

  Subsequently, the streak unevenness detection unit 64 sets one rectangular display area in the target image as a target rectangular display area, and displays a plurality of rectangular displays adjacent to each streak uneven element line segment in the target rectangular display area and the target rectangular display area. Whether or not to be connected to each stripe unevenness element line segment included in each of the areas (hereinafter collectively referred to as “adjacent rectangular area group”) is determined in the same manner as the process shown in FIG. 8 in the stripe area update unit 632. . Specifically, when the leftmost and uppermost rectangular display area 711a in the target image 71 of FIG. 5 is the target rectangular display area, the right rectangular display area 711b of the target rectangular display area 711a, the target rectangle The rectangular display area 711c at the lower right of the display area 711a and the rectangular display area 711d under the target rectangular display area 711a are set as an adjacent rectangular area group. Then, two stripe unevenness element line segments respectively belonging to the target rectangle display area 711a and the adjacent rectangle area groups 711b to 711d are specified, and the distance between the centers of gravity of the two stripe unevenness element areas respectively corresponding to the two stripe unevenness element line segments is determined. The distance between the connecting line and each end point of the two streaky element line segments is equal to or less than a predetermined fourth threshold, and the distance between the closest end points between the two streaky element line segments and the two streaky element elements The ratio of the sum of the lengths of the line segments is equal to or less than a predetermined fifth threshold, and the sum of the distance between the farthest end points between the two streaky element line segments and the length of the two streaky element line segments When the ratio to is greater than or equal to a predetermined sixth threshold value, the connection of the two stripe unevenness element line segments is permitted, and in other cases, the connection is rejected (see FIG. 8).

  In the streak unevenness detection unit 64, the above processing is repeated while sequentially switching the target rectangular display areas in a plurality of rectangular display areas (however, those already set as the target rectangular display areas are not included in the adjacent rectangular area group. 2) Among the plurality of streak unevenness element line segments, two streaks having the same longitudinal direction and arranged in close proximity to each other in the longitudinal direction and existing in two rectangular display areas adjacent to each other A combination of uneven element line segments is detected (step S19). The two stripe unevenness element line segments related to each combination are associated with each other as having a high possibility of being derived from one stripe unevenness on the substrate 9.

  In the display control unit 65, one line segment is derived from the two stripe unevenness element line segments related to each combination in the same manner as described with reference to FIG. That is, after acquiring these four segmental segments by segmenting these non-uniformity element line segments at their midpoints, the principal axes of inertia for the set of four segmental line segments are obtained. Of the four intersections of the perpendicular to the principal axis of inertia and the principal axis of inertia and the two farthest intersections are generated as connected line segments connecting the two streaky element lines Is done. When one of the two stripe unevenness element line segments is also associated with the other stripe unevenness element line segment, the above processing is performed for all of these stripe stripe element line segments to generate one connected line segment. Is done. The connection line segment can be regarded as a representative line segment of a connection area (an area showing the entire stripe unevenness) obtained by connecting a plurality of stripe unevenness element areas derived from one stripe unevenness (highly likely).

  Subsequently, when the operator inputs the minimum value of the length of the connecting line segment to be displayed via the input unit 56 and is accepted by the calculation unit 6 (step S20), as shown in FIG. A connecting line segment 731 having a length equal to or longer than the minimum value is displayed on the display 55 so as to overlap the target image 71 (step S21). That is, the presence position of the connected area having a length equal to or longer than the minimum value is displayed on the display 55. As a result, the operator can easily check only the stripe unevenness having a length equal to or longer than the minimum value while extending over the plurality of rectangular display areas 711. It should be noted that the streak uneven element line segment in which the connecting line segment is not generated (that is, the streak uneven element line segment that is not permitted to be connected to other streak uneven element line segments and indicating almost the entire streak unevenness by itself) In addition, those having a length equal to or greater than the minimum value may be similarly displayed on the display 55.

  Further, in the unevenness inspection apparatus 1, before displaying the connecting line segment on the display 55, a binary value in which a muscle region line segment exists in a plurality of region groups to which a plurality of muscle unevenness element line segments from which each connecting line segment originates belongs. The threshold range corresponding to the image is obtained as the streak unevenness intensity, and the streak unevenness intensity can be specified by changing the color and thickness of each connecting line segment when displayed on the display 55 of the connected line segment. Also good. In addition, the streak unevenness strength and the length of the connecting line segment for each connecting line segment (which may be the area of the connecting area when the connecting area is actually obtained, as will be described later) and a predetermined strength threshold value and By comparing with each of the length threshold value (area threshold value), it is determined whether or not streak unevenness, which is a set of a plurality of streak unevenness elements indicated by the connecting line segment, is allowed (that is, whether or not it is a defect). It is also possible to do this.

  As described above, the unevenness inspection apparatus 1 masks an area corresponding to the gap between the rectangular display areas on the substrate 9 in the multi-tone original image acquired by imaging the substrate 9 so that the target image is displayed. Based on a plurality of binary images prepared and derived from the target image using a plurality of threshold values, a plurality of streaky element line segments each representing a streaky element region are identified. By detecting two stripe unevenness element line segments that are the same in the longitudinal direction and are arranged in the longitudinal direction and are present in the adjacent rectangular display area among the plurality of stripe unevenness element line segments. It is possible to easily detect the stripe unevenness extending over the rectangular display area. As a result, the true length, starting point, or end point of streak unevenness can be obtained with high accuracy, and as a result, the cause of streak unevenness can be efficiently identified and the manufacturing process and the pattern to be formed can be improved. Become.

  Further, in the streak unevenness element specifying unit 63, among the plurality of streak region line segments specified in one rectangular display region of the binary image, the longitudinal direction is the same, the longitudinal direction is arranged, and they are close to each other The two muscle region line segments to be detected are detected by the same algorithm as the processing for detecting the muscle unevenness element line segments that can be connected by the muscle unevenness detecting unit 64, and updated to one muscle region line segment. Here, since the streak unevenness element line segment is the longest of a plurality of streak area line segments included in the area group, the above processing for the streak line segment by the streak unevenness element specifying unit 63 is performed in one rectangular display area. Among the plurality of streak unevenness element lines specified in the inside, the same as the process in the streak unevenness detection unit 64 for two streak unevenness element lines that have the same longitudinal direction, are arranged in the longitudinal direction, and are close to each other. It can be understood as a process of detecting by the above algorithm and updating it to one streak unevenness element line segment. As described above, in the streak unevenness element specifying unit 63, a plurality of streak unevenness element segments that are highly likely to be derived from the same streak unevenness in one rectangular display area are substantially converted into one streak unevenness element line segment. As a result of the update, the unevenness inspection apparatus 1 can efficiently perform subsequent processing in the stripe unevenness detection unit 64 and the display control unit 65. Further, in the display control unit 65, the existence position of the connected area is displayed on the display 55 by a connecting line segment connecting two streaky element line segments derived from one streak unevenness, so that the operator It is possible to easily confirm the stripe unevenness extending over the rectangular display area.

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

  In the unevenness inspection apparatus 1 of FIG. 1, the muscle unevenness inspection may be performed without the muscle unevenness element specifying unit 63 specifying the muscle unevenness element region by the muscle unevenness element line segment. In this case, when specifying the streak unevenness element region, the streak region updating unit 632 has a plurality of streak regions that have the same longitudinal direction, are arranged in the longitudinal direction, and are adjacent to each other in one binary region. The area group acquisition unit 633 obtains area groups each indicating a streak unevenness element by grouping the overlapping area in two binary images adjacent to each other in the same area group. Here, the streak unevenness element region has the longest length in the longitudinal direction among the plurality of streak regions included in the region group. Therefore, the processing in the streak region update unit 632 is substantially binary. Among the plurality of streak unevenness element regions specified in one rectangular display region in the image, two streak unevenness element regions having the same longitudinal direction and arranged in the longitudinal direction and close to each other are detected. This corresponds to a process of updating two streak unevenness element regions to one streak unevenness element region. In addition, the streak unevenness detection unit 64 detects two streak unevenness element areas that are the same in the longitudinal direction and are arranged in the longitudinal direction and are present in the adjacent rectangular display area among the plurality of streak unevenness element areas. In the display control unit 65, a connected region that connects the two detected streaky unevenness element regions is generated, and the position of the connected region is overlapped with the target image by a line indicating the edge of the connected region. It is displayed on the display 55. However, from the viewpoint of more easily detecting streak unevenness extending over a plurality of rectangular display areas, the streak unevenness element specifying unit 63 specifies a streak unevenness element area by a streak unevenness element line segment representing the area, In the streak unevenness detection unit 64 and the display control unit 65, it is preferable that the streak unevenness element line segment is handled as a corresponding streak unevenness element region to simplify the process.

  In the above embodiment, a streak unevenness element line segment (or streak unevenness element region) is specified from a plurality of binary images derived from a target image using a plurality of thresholds, but binary using only one threshold. When acquiring an image, in the binary image, a plurality of closed regions in which the ratio of the length in the longitudinal direction to the width in the direction perpendicular to the longitudinal direction is equal to or greater than a predetermined value are directly specified as a plurality of streaky element regions. May be.

  In the non-uniformity detection unit 64, in each combination of two non-uniformity element line segments existing in the adjacent rectangular display area, the distance between the straight line passing through the center of gravity of the two non-uniformity element line segments and each end point, and two By obtaining the ratio of the distance between the nearest end point distance and the farthest end point distance between the streak unevenness element line segments and the sum of the lengths of the two streak unevenness element line segments, the two streak unevenness elements that can be connected are obtained. Although two line unevenness element line segments that are determined to be connectable but are determined to be connectable are at least the same in the longitudinal direction, arranged in the longitudinal direction, and in two rectangular display areas adjacent to each other, respectively. It only needs to be present and does not necessarily have to be close. In addition, detection of two streaky element line segments that can be connected is performed by, for example, two lines obtained by extending two streaky element line segments in each combination of two streaky element line segments existing in an adjacent rectangular display area. It is also possible to use other algorithms such as obtaining the angle formed by the straight line.

  In the above embodiment, a resist film is formed on the substrate 9, but if the liquid is applied to the main surface, the material of the film formed on the substrate is a resist solution. It may be other than. The unevenness inspection apparatus 1 is particularly suitable for inspecting streaks on a glass substrate, but a plurality of rectangular display areas having a uniform pattern are set to be aligned vertically and horizontally with a gap therebetween, thereby displaying a plurality of rectangular displays. It may be used for inspecting streaks on other substrates that are multi-faced according to the region.

It is a figure which shows the structure of a nonuniformity inspection apparatus. It is a figure which shows the structure of a computer. It is a block diagram which shows the function structure which a computer implement | achieves. It is a figure which shows the flow of the process which a nonuniformity inspection apparatus test | inspects the stripe nonuniformity on a board | substrate. It is a figure which shows a target image. It is a figure which shows a binary image. It is a figure which shows a binary image. It is a figure which shows a binary image. It is a figure which shows a closed region. It is a figure for demonstrating the decision | availability of the connection of a muscle area line segment. It is a figure for demonstrating the connection of a muscle region line segment. It is a figure which overlaps and shows the line segment line segment in two binary images. It is a figure which overlaps and shows a connecting line segment on a target image.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Nonuniformity inspection apparatus 5 Computer 8 Recording medium 9 Board | substrate 41 Imaging part 55 Display 61 Target image generation part 63 Muscle unevenness element specific | specification part 64 Muscle unevenness detection part 71 Target image 92 Film | membrane 541 Program 711,711a-711d Rectangular display area 719 Background area 721a-721c closed region 731 connecting line segment S14-S21 step

Claims (8)

A non-uniformity inspection method for inspecting non-uniformity on a substrate that is set by aligning a plurality of rectangular regions having a uniform pattern vertically and horizontally with a gap, and is multi-faced according to the plurality of rectangular regions,
a) preparing a target image by masking a region corresponding to the gap in the multi-tone original image obtained by imaging the substrate;
b) In the binary image obtained by binarizing the target image, a plurality of closed regions in which the ratio of the length in the longitudinal direction to the width in the direction perpendicular to the longitudinal direction is a predetermined value or more are identified as a plurality of streaky element regions. And a process of
c) detecting two stripe unevenness element areas that are the same in the longitudinal direction and are arranged in the longitudinal direction and are present in adjacent rectangular areas, among the plurality of stripe unevenness element areas;
An unevenness inspection method comprising: The unevenness inspection method according to claim 1,
In the step b), the stripe unevenness element region is specified by the stripe unevenness element line representing the region, and in the step c), the stripe unevenness element line is treated as the corresponding stripe unevenness element region. Unevenness inspection method. The unevenness inspection method according to claim 1 or 2,
d) A method for inspecting unevenness, further comprising a step of displaying on a display unit the position of a connected region obtained by connecting the two streaky unevenness element regions. The unevenness inspection method according to claim 3,
e) Before the step d), the unevenness inspection method further comprising a step of accepting an input of a minimum value of the length of the connected area where the existence position is displayed in the step d). The unevenness inspection method according to any one of claims 1 to 4,
Among the plurality of streak uneven element regions specified in one rectangular region, the step b) includes two streak uneven element regions that have the same longitudinal direction, are arranged in the longitudinal direction, and are close to each other. Is detected by the same algorithm as in step c), and the two streaky unevenness element regions are updated to one streak unevenness element region. The unevenness inspection method according to any one of claims 1 to 5,
The unevenness inspection method, wherein the substrate has a film formed by applying a liquid on one main surface. A plurality of rectangular areas having a uniform pattern are set to be aligned vertically and horizontally with a gap, and a non-uniformity inspection apparatus that inspects streaks on a substrate that is multi-faced according to the plurality of rectangular areas,
An imaging unit for imaging the substrate to obtain a multi-tone original image;
A target image generation unit that generates a target image by masking a region corresponding to the gap of the original image;
A streak that identifies a plurality of closed regions in which a ratio of a length in a longitudinal direction to a width in a direction perpendicular to the longitudinal direction is a predetermined value or more as a plurality of streak unevenness element regions in a binary image obtained by binarizing the target image An uneven element identification part;
Among the plurality of stripe unevenness element regions, the stripe unevenness detection unit that detects two stripe unevenness element regions that are the same in the longitudinal direction, are arranged in the longitudinal direction, and exist in adjacent rectangular regions;
A nonuniformity inspection apparatus comprising: A program in which a plurality of rectangular areas having a uniform pattern are set to be vertically and horizontally aligned with a gap therebetween, and causes a computer to inspect streaks on a substrate that is multi-faced according to the plurality of rectangular areas. Is executed by the computer,
a) preparing a target image by masking a region corresponding to the gap in the multi-tone original image obtained by imaging the substrate;
b) In the binary image obtained by binarizing the target image, a plurality of closed regions in which the ratio of the length in the longitudinal direction to the width in the direction perpendicular to the longitudinal direction is a predetermined value or more are identified as a plurality of streaky element regions. And a process of
c) detecting two stripe unevenness element areas that are the same in the longitudinal direction and are arranged in the longitudinal direction and are present in adjacent rectangular areas, among the plurality of stripe unevenness element areas;
A program characterized by having executed.

Images