JP2011007621A - Apparatus for measurement of two-layer circular displacement - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a two-layer circular displacement measurement apparatus for stably detecting circular barycenters of two layers, calculating the displacement quantity of a two-layer circle from the detected barycenters of two circles, and measuring the displacement of the two-layer circle when the displacement quantity of the two-layer circle is measured.SOLUTION: The two-layer circular displacement measurement apparatus includes: an imaging means for imaging a circular object entirely having two layers or more from the upside; a means for setting an inspection area and the center of the inspection area; a means for setting a plurality of edge detection regions of an outer circle; a means for detecting a plurality of edges of the outer circle; a means for obtaining a tentative barycenter of the outer circle; a means for obtaining the barycenter of the outer circle; a means for obtaining a plurality of edge detection regions of an inner circle; a means for detecting a plurality of edges of the inner circle; a means for obtaining a tentative barycenter of the inner circle; a means for obtaining the barycenter of the inner circle; and a means for calculating the displacement quantity between the outer and inner circles from the barycenters of the outer and the inner circles.

Description

  The present invention relates to a two-layer circular displacement measuring apparatus for a circular object having two or more layers formed on a color filter substrate or the like.

  As a circular object having two or more layers, a pattern formed on a color filter substrate will be described as an example.

  FIG. 1 is a cross-sectional view showing an example of a color filter used in a color liquid crystal display device. On a glass substrate 10, a black matrix (hereinafter referred to as BM) 11, a red R colored pixel (hereinafter referred to as R pixel) 12a, A green G colored pixel (hereinafter referred to as G pixel) 12b, a blue B colored pixel (hereinafter referred to as B pixel) 12c, a transparent electrode 13, and a photo spacer (hereinafter referred to as PS) 14a are sequentially formed. is there.

  2 shows an enlarged view of a portion indicated by a broken line 15 in FIG. 1, and FIG. 3 shows an enlarged view of FIG. 2 viewed from above. In FIG. 2, the portion 14b is, for example, 16 is a layer formed of red colored photoresist (hereinafter referred to as R layer), 17 is a layer formed of green colored photoresist (hereinafter referred to as G layer), and 18 is blue. A layer formed of a colored photoresist (hereinafter referred to as B layer), which is formed simultaneously with the formation of the R pixel 12a, the G pixel 12b, and the B pixel 12c, and has a conical shape. Furthermore, after the transparent electrode 13 is formed, a part of PS 14a for avoiding contact with the opposing drive electrode during cell assembly is formed.

  As a method for producing a color filter having the above structure, a photolithography method, a printing method, and an ink jet method are known.

  FIG. 4 is a flowchart showing steps of a commonly used photolithography method.

  In the color filter, first, a step of forming BM on the glass substrate (C-1), a step of cleaning the glass substrate (C-2), and a step of applying and pre-drying a colored photoresist (C-3) ), A pre-baking step (C-4) for drying and curing the colored photoresist, a step (C-5) for exposing, a step (C-6) for developing, and a step (C-) for curing the colored photoresist. 7) The process of forming a transparent electrode (C-8) and the process of forming PS (C-9) are performed in this order.

  For example, in the case of forming pixels in the order of R pixel, G pixel, and B pixel, from the step of cleaning the color filter glass substrate (C-2) to the step of curing the colored photoresist (C-7) In the meantime, the color resist is changed in the order of red R, green G, and blue B, and the process is repeated three times to form R pixels, G pixels, and B pixels.

  There are various standard management items during the production of the color filter, but the height and position of the PS (14 in FIG. 2) formed during the production of the color filter affects the final product, so strict quality control is required. It is done. Therefore, the product is guaranteed by measuring and managing the PS height and position. In particular, if there is a displacement in one of the R layer 16, G layer 17, B layer 18 and part 14a of PS shown in FIG. 2 and FIG. The positional misalignment between the layers forming the layer is strictly managed in terms of quality control.

Therefore, when forming the PS in the middle of manufacturing the color filter, the position of each layer is sequentially positioned so that it is located at the center of the lower layer 20 as shown in FIG. Must be formed. As shown in FIG. 5B, when one of the layers is shifted to one side, it causes a position defect, resulting in a shape defect.

  In the conventional two-layer circular positional deviation measuring method, there is a method of manually measuring a circular boundary portion by an operator. However, in the case of manual measurement, there is a problem that human error becomes large because the operator measures the vertical and horizontal intervals from the captured image.

  In addition, a method of measuring the pixel interval shown in FIG. 6 from the captured image of the measurement site is also adopted in order to standardize the positional deviation of the two-layer circle. That is, as shown in FIG. 6, for example, the outer circumference 24 of the PS 22 and the dimension to the boundary 25 of the PS 22 and the colored layer 23 are measured in four places, left and right and up and down, and │HG│ and │EF│ are set values. If it is below, the position of PS22 is judged to be good. However, in this measurement method, the boundary portion 24 and the boundary portion 25 are unclear when the measurement site is imaged, so that detection of the boundary portion becomes unstable. Therefore, there is a problem that the measurement results vary.

Japanese Patent Laid-Open No. 11-288463 Japanese Patent Application No. 2008-330027

  The present invention has been made in view of the above-described problems. When measuring the displacement amount of a two-layer circle, the center of gravity of the two layers is stably detected, and the two centroids of the detected two circles are detected. It is an object of the present invention to provide a two-layer circular misalignment measuring device that calculates the misalignment amount of a layer circular and can measure the misalignment of the two-layer circular.

  The invention according to claim 1 of the present invention is an image pickup means for picking up a circular object having two or more layers as a whole from above, and means for setting the inspection area and the center of the inspection area from the image obtained by the image pickup means. Means for setting a plurality of edge detection ranges of the outer circle in the inspection area, means for detecting a plurality of edges of the outer circle from the plurality of edge detection ranges of the outer circle, and a plurality of edges of the outer circle Means for calculating the temporary center of gravity of the outer circle, means for determining the center of gravity of the outer circle from the temporary center of gravity of the outer circle, means for determining a plurality of edge detection ranges of the inner circle from the center of gravity of the outer circle and the outer circle, and a plurality of edges of the inner circle Means for detecting a plurality of edges of the inner circle from the detection range, means for determining the temporary center of gravity of the inner circle from the edges of the inner circle, means for determining the center of gravity of the inner circle from the temporary center of gravity of the inner circle, and Of the center of gravity and inner circle Is sincerely a two-layer circular positional deviation measuring device characterized by comprising a means for calculating a positional deviation amount of the outer circle and the inner circle.

  In the invention according to claim 2 of the present invention, the means for setting the inspection area and the center of the inspection area sets the center of the inspection area and the inspection area by pattern matching of the pre-registered matching and the image captured by the imaging means. The two-layer circular misregistration measuring apparatus according to claim 1.

  In the invention according to claim 3 of the present invention, the means for setting a plurality of edge detection ranges of the outer circle is provided with a plurality of line segments from the outside of the inspection area toward the center of the inspection area, 3. The two-layer circular misregistration measuring apparatus according to claim 1, wherein a range surrounded by a plurality of line segments provided toward the center of the inspection area is set as an edge detection range.

  In the invention according to claim 4 of the present invention, the means for detecting a plurality of edges of the outer circle uses the Nth detected edge from the outside in the edge detection range as the edge of the outer circle, and a part of the outside of the detection area. 4. The two-layer circular position measuring apparatus according to claim 1, wherein edge detection is performed from the point to the center of the inspection area.

  In the invention according to claim 5 of the present invention, the means for obtaining the provisional center of gravity of the outer circle provides a group of three edges from a plurality of edges of the obtained outer circle, and the number of outer circles equal to the number of groups is provided. 5. The two-layer circular misregistration measuring apparatus according to claim 1, wherein a temporary center of gravity is obtained.

  In the invention according to claim 6 of the present invention, the means for obtaining the center of gravity of the outer circle deletes the non-standard provisional center of gravity from the plurality of provisional centers of gravity of the outer circle, and three provisional centers of gravity from the remaining provisional centers of gravity. , Find the same number of new temporary centroids as the number of groups, and obtain new temporary centroids until the total of the calculated temporary centroids and the temporary centroids not included in the group is 3 or less, If the total of the calculated new temporary center of gravity and the temporary center of gravity not included in the group is two, the two temporary centers of gravity are averaged to obtain the center of the outer circle. If the total is 1, the temporary center of gravity is outside. 6. The two-layer circular misregistration measuring apparatus according to claim 1, wherein the center of gravity of the circle is used.

  In the invention according to claim 7 of the present invention, the means for setting a plurality of edge detection ranges of the inner circle includes a plurality of line segments from the center of gravity of the outer circle toward the outer circle, and the plurality of line segments and the outer circle are used. 7. The two-layer circular misregistration measuring apparatus according to claim 1, wherein the enclosed range is an inner circle edge detection range.

  In the invention according to claim 8 of the present invention, the means for detecting a plurality of edges of the inner circle uses the Nth edge detected from the outer circle in the edge detection range of the inner circle as the edge of the inner circle, and 8. The two-layer circular misregistration measuring apparatus according to claim 1, wherein edge detection is performed from some points toward the center of gravity of the outer circle.

  In the invention according to claim 9 of the present invention, the means for calculating the provisional center of gravity of the inner circle forms a group of three edges from the determined edges of the inner circle, and the same number of inner circles as the number of groups is obtained. The temporary center of gravity is obtained, and the two-layer circular misregistration measuring apparatus according to any one of claims 1 to 8.

  In the invention according to claim 10 of the present invention, the means for obtaining the center of gravity of the inner circle deletes the non-standard provisional center of gravity from the plurality of provisional centers of gravity of the inner circle, and three provisional centers of gravity from the remaining provisional centers of gravity. The number of temporary centroids equal to the number of groups is calculated, and further new temporary centroids are obtained until the total of the calculated temporary centroids and the temporary centroids not included in the group becomes three or less, If the total of the calculated new temporary center of gravity and the temporary center of gravity not included in the group is two, the two temporary centers of gravity are averaged to obtain the center of the outer circle. If the total is one, the temporary center of gravity is set inside. The two-layer circular misalignment measuring device according to any one of claims 1 to 9, wherein the center of gravity of a circle is used.

  According to the eleventh aspect of the present invention, the means for calculating the positional deviation amount is determined from | Xout based on the determined center of gravity coordinates (Xout, Yout) of the outer circle and the determined center of gravity coordinates (Xin, Yin) of the inner circle. 11. The two-layer circular misregistration measuring apparatus according to claim 1, wherein -Xin | and | Yout-Yin | are calculated.

In the invention according to claim 12 of the present invention, a threshold value of the positional deviation amount of the outer circle and the inner circle is set in advance, and when the calculated positional deviation amount exceeds the threshold value, an alarm signal is generated and the manufacturing process is performed. The two-layer circular misregistration measuring apparatus according to any one of claims 1 to 11, wherein feedback is provided.

  Since the conventional method cannot stably detect the boundary between the two-layered circular edges, the measurement of the positional deviation of the two-layered circular has varied. However, according to the two-layer circular misalignment measuring apparatus of the present invention, the center of gravity of each of the two-layer circles can be obtained stably, so that measurement without variation is possible. In addition, when the calculated displacement amount of the two-layer circular shape exceeds a preset threshold value, it is expected to suppress the generation of defective products by generating an alarm signal and feeding back to the manufacturing process.

The figure which showed in cross section an example of the color filter used for a color liquid crystal display device The figure which expanded the part shown with the broken line 15 of FIG. An enlarged view of FIG. 2 as viewed from above. Schematic block diagram showing the steps of a commonly used photolithography method Fig. 5 (a) is a diagram showing the position of two layers. Fig. 5 (b) is a diagram showing a case where one of the layers is shifted to one side. The figure which shows the method of measuring the position shift between two layers of the conventional method The figure which showed PS of the color filter substrate used in order to carry out 2 layer circular position shift measurement using the 2 layer circular position shift measuring device concerning the present invention in a section. Schematic of an example of a two-layer circular misalignment measuring apparatus according to the present invention The top view which showed typically a part of color filter board | substrate used when performing two-layer circular position shift measurement using the two-layer circular position shift measuring apparatus which concerns on this invention The figure which showed typically the image of PS imaged with the image pick-up part of the two-layer circular displacement measuring device concerning the present invention. The figure for demonstrating the method of measuring the amount of double layer circular position shifts using the two layer circular position shift measuring device concerning the present invention. Flow diagram for obtaining the center of gravity of the outer circle according to the present invention FIG. 13A is a schematic diagram of a matching image registered in advance for pattern matching. FIG. 13B is a diagram for explaining the means for setting the outer circle inspection area and the inspection area center according to the present invention. FIG. 13C is a schematic diagram of the captured image captured by the imaging unit. FIG. 13C illustrates the center of the inspection area and the inspection area. The figure for demonstrating the means to detect the several edge of the outer side circle which concerns on this invention The figure which shows one edge detection range among the several edge detection ranges of the outer circle which concerns on this invention Schematic diagram of multiple edges of a detected outer circle according to the present invention The figure which shows the temporary gravity center of the outer side circle which concerns on this invention The figure for demonstrating the method of calculating | requiring the standard of the temporary center of gravity outside the standard based on this invention The figure for demonstrating the method of calculating | requiring a new temporary center of gravity and a further center of gravity again from the remaining temporary center of gravity which concerns on this invention FIG. 20A is a case where there are 16 detection edges. FIG. 20B is a case where there are 100 detection edges. Flow chart showing means for obtaining the center of gravity of the inner circle according to the present invention The figure for demonstrating the means to set the some edge detection range of the inner circle which concerns on this invention. The figure which shows the edge detection range of one inner circle among the several edge detection ranges of the inner circle which concerns on this invention Schematic diagram of a plurality of edges of an inner circle according to the present invention The figure which shows the temporary center of gravity of the inner side circle which concerns on this invention The figure explaining deleting the temporary non-standard temporary center of gravity which concerns on this invention The figure for demonstrating the method of calculating | requiring a new temporary center of gravity and the final center of gravity from the temporary center of gravity of the remaining inner circle concerning this invention.

  Hereinafter, an embodiment for carrying out a two-layer circular misregistration measuring apparatus according to the present invention will be described with reference to the drawings.

  FIG. 7 is a view showing a cross-section of the PS of the color filter substrate used when the two-layer circular displacement measurement is performed using the two-layer circular displacement measuring apparatus according to the present invention. Colored pixels of BM31, R pixel 32, and B pixel 33 are formed on the glass substrate 30, and a part of PS 35 having three layers of R layer 36, G layer 37, and B layer 38 on BM31. Further, a PS part 39 is formed thereon to constitute PS40. The colored layers 36, 37 and 38 are formed simultaneously when the colored pixels are formed.

  There are an R layer 36, a G layer 37, a B layer 38, and a part 35 of PS as a circle, but for performing a two-layer circular displacement measurement using the two-layer circular displacement measuring apparatus according to the present invention. In the embodiment, a case where the PS part 39 and the R layer 36 are formed as a two-layer circle will be described as an example.

  FIG. 8 is a schematic view showing an example of a two-layer circular misalignment measuring apparatus used when measuring a two-layer circular misalignment formed on a color filter substrate according to the present invention.

  The color filter substrate 41 is placed on the measurement stage 42. The measurement stage 42 is driven by an X-axis drive unit 45 and a Y-axis drive unit 46. The imaging unit 43 as an imaging unit has a light source, a lens, a half mirror, and a camera, and is driven by a Z-axis drive unit 47. Illumination light emitted from the light source illuminates the color filter substrate 41 via a lens, a half mirror, and the like, and the illuminated color filter substrate 41 is imaged from above by a camera via the lens and half mirror. The control unit 44 includes a storage unit that stores images, a display unit that displays measurement results, an X-axis drive unit 45 that drives the measurement stage 42, a Y-axis drive unit 46, and a Z-axis drive unit 47 that drives the imaging unit 43. A control unit that controls the imaging unit 43 and the like, an operation unit for operator operation, and a calculation unit that calculates image information are provided. The measurement stage 42 on which the color filter substrate 41 is placed has a mechanism for adsorbing the color filter substrate 41 and preventing the substrate from shifting.

  The timing of measuring the two-layer circular positional deviation is, for example, when the formation of the colored pixels of the color filter is performed in the order of the R pixel, the G pixel, and the B pixel, after the R layer 36 and the G layer 37 are formed. Whether to measure misalignment between the layer 36 and the G layer 37, or to measure misalignment between the B layer 38 and the R layer 36 or the G layer 37 after the R layer 36, the G layer 37, and the B layer 38 are formed. Alternatively, it is appropriately selected whether the positional deviation measurement between the PS portion 39 and the R layer 36, the G layer 37, or the B layer 38 is performed after the PS portion 39 is formed.

  FIG. 9 is a top view schematically showing a part of a color filter substrate used when measuring a two-layer circular position using the two-layer circular position deviation measuring apparatus according to the present invention. Reference numeral 40 denotes a PS formed on the BM 51, 52 denotes an R pixel, 53 denotes a G pixel, and 54 denotes a B pixel.

FIG. 10 is a diagram schematically showing a PS image picked up by the image pickup unit 43 which is an image pickup means. PS40 is a P made of colored layers of R layer 36, G layer 37 and B layer 38 formed on BS 31.
It consists of a part 35 of S and a part 39 of PS, and each layer has a circular shape.

  FIG. 11 is a diagram for explaining a method of measuring a two-layer circular misalignment according to the present invention. In the measurement of the positional deviation amount of the two-layer circle, first, the center of gravity positions of the outer circle 55 and the inner circle 56 are respectively determined, and then the center coordinates (Xout, Yout) 57 of the outer circle and the center of gravity coordinates (Xin, Yin) 58, | Xout−Xin | = X and | Yout−Yin | = Y are obtained, and X and Y are used as positional deviation amounts.

  When a 3 mm × 3 mm captured image is obtained with a resolution of 1 μm per pixel using a two-dimensional camera having 3000 × 3000 pixels as the imaging unit 43, 1 in the + direction of the X axis from the center of coordinates (may be arbitrary). The coordinates (X1, Y1) of the point X1 away from the pixel and the point Y1 one pixel away in the + direction in the Y-axis direction are 1 μm away from the center of the coordinate in the + direction in the X-axis direction and 1 μm in the + direction in the Y-axis direction. The position is indicated.

  The procedure for determining the center of gravity of the outer circle and the center of the inner circle in the present invention is to first determine the center of gravity of the outer circle and then determine the center of gravity of the inner circle.

  FIG. 12 is a flowchart for obtaining the center of gravity of the outer circle. After the start (S-1), the inspection area and the center of the inspection area are set by pattern matching (S-2). A means for setting the inspection area and the center of the inspection area is shown in FIG.

  FIG. 13A is a schematic diagram of a matching image registered in advance for pattern matching. FIG. 13B is a diagram illustrating an image capturing unit 43 of the two-layer circular misregistration measuring apparatus illustrated in FIG. The schematic diagram of the captured image is shown. From the matching image registered in advance for pattern matching in FIG. 13A and the captured image shown in FIG. 13B, the inspection area 59 and the center 61 of the inspection area shown in FIG. Ask. The inspection area and the center of the inspection area are obtained from the matching image and the captured image by generally used pattern matching.

  Next, edges are detected from the outside to the inside of the obtained inspection area (S-3), and a plurality of edges of the outer circle are detected (S-4). 14 and 15 are diagrams for explaining a method of detecting an edge, and the edge is emphasized. To detect an edge, first, a plurality of edge detection ranges of the outer circle are set. A means for setting a plurality of edge detection ranges of the outer circle will be described. Line segments 62a, 62b, 62c,... Are provided from the outside 60 of the inspection area toward the center 61 of the inspection area (in the case of FIG. 14, the total number of line segments is 16) and is surrounded by the outside 60 of the inspection area and the line segments. The triangular edge detection ranges 63-1, 63-2, 63-3 to 63-16 are set (in the case of FIG. 14, 16 edge detection ranges are set).

  The number of line segments provided from the outside 60 of the inspection area toward the center 61 of the inspection area is not limited to 16. Similarly, the edge detection range is not limited to 16.

  FIG. 15 shows one edge detection range 63-1 of the set 16 edge detection ranges shown in FIG. In the edge detection range 63-1, 64 is BM, 65 is a part of PS, 66 is an R layer, 67 is a G layer, 68 is a B layer, and 61 is the center of the inspection area. 69 is the boundary between the BM 64 and the PS part 65, 70 is the boundary between the PS part 65 and the R layer 66, 71 is the boundary between the R layer 66 and the G layer 67, and 72 is the boundary between the G layer 67 and the B layer 68. It was emphasized.

A means for detecting a plurality of edges of the outer circle will be described. The edge detected in advance from the outside in the inspection area is used as the edge of the outer circle. In the embodiment of the present invention, N = 1
As an example, a part of the PS and the R layer are formed as a two-layer circle. Therefore, the edge first detected from the outside (the boundary 70 between the BM 64 and the part 65 of the PS) is used as the edge of the outer circle. In the edge detection range 63-1 in FIG. 15, for example, edge detection is performed along a line segment 75 from a part 60 a outside the inspection area 60 indicated by 60 a toward the center 61 of the inspection area.

  In the embodiment of the present invention, a case where one edge along the line segment 75 is detected in one edge detection range 63-1 will be described as an example. However, the present invention is not limited to this. A plurality of line segments may be provided from one edge detection range, and the number of edges corresponding to the line segments may be detected.

  Edge detection generally uses a binarization method, that is, a method of binarizing an image to detect a portion that changes from white to black or from black to white, or a gray method, that is, a gray level value. An edge can be detected by using a method of differentiating the change and detecting a portion that is greater than or less than a threshold value as an edge.

  Edge detection is performed for all 16 edge detection ranges 63-1, 63-2, 63-3 to 63-16 shown in FIG. FIG. 16 is a schematic diagram of detected edges. 83-1 is an edge obtained from the edge detection range 63-1 in FIG. 14, and 83-2 is obtained from the edge detection range 63-2. The edge 83-3 is an edge obtained from the edge detection range 63-3, and 83-16 is an edge obtained from the edge detection range 63-16. Reference numeral 61 denotes the center of the inspection area.

  After a plurality of edges of the outer circle are detected, a group of 3 edges out of 16 detected edges is formed (S-5). A means for obtaining the temporary center of gravity of the outer circle will be described. In order to obtain the temporary center of gravity of the outer circle, first, an edge is selected. A group of edges for every three obtained edges is determined, and an edge is selected so that all edges are assigned to any group. That is, a group of three edges is created from the obtained 16 edges shown in FIG. Three edges are selected so that a triangle formed by three edges is a triangle having no obtuse angle. For example, in the case of 16 divisions as in the example of the present embodiment, three edges are assigned to a group such as (first, sixth, eleventh) and (second, seventh, twelfth), and a group of edges is assigned. A provisional center of gravity is obtained from three edges for each group.

  The (first, sixth, eleventh) edges refer to the obtained edges 83-1, 83-6, 83-11 shown in FIG. The (second, seventh, twelfth) edges refer to the obtained edges 83-2, 83-7, 83-12 shown in FIG. Similarly, (3rd, 8th, 13th), (4th, 9th, 14th), (5th, 10th, 15th) groups are created, and a total of 5 groups are created. In the example of the present embodiment, since 16 edges are detected, the above five groups are created, and the remaining one detection edge 83-16 is an unselected edge.

  Next, a temporary center of gravity is obtained for every group of three selected edges (S-6). The temporary centroid can be obtained by using a geometric method, and the five centroid coordinates (Xout1, Yout1), (Xout2, Yout2), (Xout3, Yout3), (Xout4, Yout4), (Xout5) shown in FIG. , Yout5). In this case, (Xa, Ya) is a coordinate indicating the center 61 of the inspection area and may be regarded as (Xa, Ya) = (0, 0). For example, the coordinate (Xout1, Yout1) is from (Xa, Ya). When the position is one pixel of the camera imaged in the plus direction of the X axis and two pixels of the camera imaged in the plus direction of the Y axis, (1, 2) is indicated.

The non-standard temporary centroid is deleted from the five temporary centroids having the obtained temporary centroid coordinates (S-7).
The non-standard temporary center of gravity here refers to a temporary center of gravity that is out of the standard by obtaining a standard from the values of all detected temporary centers of gravity.

  A method for obtaining the standard will be described by taking five centroid coordinates obtained in FIG. 18 as an example. The non-standard temporary center of gravity is defined as a non-standard temporary center of gravity that is outside the allowable range. The allowable range is obtained by the following method. First, the absolute values of the five X coordinates of the detected temporary center of gravity (Xout1, Yout1) to (Xout5, Yout5) are averaged to obtain (Xave), and similarly, the five Y coordinates of the detected center of gravity are determined. (Yave) is obtained by averaging the absolute values of Y in the Y coordinate direction. Further, a range that is more than a predetermined value (± ○ μm) in the X and Y directions from the obtained (Xave, Yave) is set as an allowable range 84, and a temporary center of gravity outside the allowable range is set as a non-standard center of gravity. The predetermined value (± ○ μm) is determined to be a deviation amount of ± ○ times or more of the obtained (Xave, Yave). For example, (Xout1, Yout1) = (1, 2), (Xout2, Yout2) = (− 3, −3), (Xout3, Yout3) = (9, 5), (Xout4, Yout4) = (− 6, 2) When (Xout5, Yout5) = (3, -4), Xave = 4.4, Yave = 3.2, and further obtained Xave = 4.4, Yave = 3.2 of 1.5 The center of gravity at a position that is double, that is, 6.6 μm away from (Xa, Ya) in the X-axis direction and 4.8 μm or more in the Y-axis direction is defined as a non-standard gravity center. In FIG. 19, (Xout3, Yout3) is the non-standard temporary center of gravity.

  After the non-standard temporary centroid is deleted from a plurality of temporary centroids obtained from all detected edges, a new temporary centroid is obtained again from the remaining temporary centroids (S-8). In the example shown in FIG. 17, (Xout3, Yout3) is deleted as a non-standard centroid, and the remaining temporary centroids (Xout1, Yout1), (Xout2, Yout2), (Xout4, Yout4), (Xout5, Yout5) are again Find the temporary center of gravity.

  Means for obtaining the center of gravity of the outer circle will be described with reference to FIG. First, a new temporary centroid is obtained again from the remaining temporary centroids obtained by deleting nonstandard values from the temporary centroid obtained from the detected edge. In FIG. 19, a new temporary centroid is obtained from the remaining temporary centroids (Xout1, Yout1), (Xout2, Yout2), (Xout4, Yout4), (Xout5, Yout5) from which the non-standard temporary centroids (Xout3, Yout3) have been deleted. First, a group of temporary centers of gravity is created as one group for every three temporary centers of gravity. In the method of selecting three temporary centroids for one group, for example, numbers are assigned in the order in which the temporary centroids are obtained, and one group is created with three temporary centroids every other number. However, if there are three provisional centroids, three are used as one group. At this time, the three temporary centroids are selected so that the triangle formed by the three temporary centroids becomes a triangle having no obtuse angle. In the case of FIG. 19, for example, number 1, number 2, and number 3 form one group, and number 4 is a temporary center of gravity that is not selected.

  A new temporary center of gravity is determined from the three temporary centers of number 1, number 2, and number 3. In this case, a new provisional center of gravity can be obtained using a geometric method in the same manner as the method of obtaining the provisional center of gravity from the three edges obtained in (S-6). Edge 3 The barycentric coordinates (Xout11, Yout11) of the circle passing through the point are obtained.

  In the example of FIG. 19, a total of two temporary centroids remain (2 of (S-10)), the temporary centroid indicated by the centroid coordinates (Xout11, Yout11) obtained as new temporary centroids and the temporary centroid of number 4 that is not selected. 2) The two temporary centroids are averaged (S-12), and the centroid 86 (Xout21, Yout21) of the outer circle is obtained (S-13), and then the process ends (S-24). When the number of provisional centroids is one in (S-11), the centroid of the provisional centroid is set as the centroid of the outer circle (S-11), and the process ends.

  When the number of temporary centroids is not one or two in (S-10) (in the case of (S-10) NO), until the number of temporary centroids becomes one or two (S-8), (S-9) is repeatedly performed.

With reference to FIG. 20 (a), the flow for obtaining the temporary center of gravity from the edges of the 16 detected outer circles and further obtaining the center of gravity of the outer circle from the temporary center of gravity in the example of the embodiment of the present invention will be described in detail. FIG. 20A shows the above-described case where 16 edges are detected, and FIG. 20B shows an example where 100 edges are detected. In the case of FIG. 20A, after detecting 16 edges (A-1), a group of 5 edges is formed from 15 edges of the 16 edges (the remaining 1 edge is a group). 5) are determined (A-2). Four temporary centroids (A-3) excluding one non-standard temporary centroid are obtained from the five temporary centroids obtained, and one new temporary centroid obtained from one temporary centroid group and the remaining one. From the two temporary centroids (A-4) in total, the two centroids are averaged to obtain the centroid. (A-5).

  When obtaining the center of gravity when there are 100 edges in the outer circle in FIG. 20B, after detecting 100 edges (B-1), 33 edges from 99 edges to 100 edges are detected. (The remaining one edge is not selected as a group) and 33 temporary centroids are obtained (B-2). For example, 29 temporary centroids excluding, for example, 4 non-standard temporary centroids from the 33 determined temporary centroids are left (B-3). A group of nine temporary centroids is created from 29 temporary centroids, and a total of eleven temporary centroids (B-), including nine new temporary centroids obtained from the nine temporary centroid groups and the remaining two temporary centroids. 4) is determined. Create 3 groups of 3 temporary centers of gravity from 11 temporary centers of gravity, 3 new temporary centers of gravity obtained from 3 groups of temporary centers of gravity and 2 remaining temporary centers of gravity, a total of 5 temporary centers of gravity (B-5). Create a temporary centroid group from five temporary centroids, and create a new temporary centroid obtained from one temporary centroid group and a total of three temporary centroids (B-6). ) One temporary centroid group is formed, and one new temporary centroid is obtained (B-7), and the obtained temporary centroid is set as the centroid (B-8).

  In this way, a group of three edges selected from a plurality of edges of the outer circle is created, a temporary center of gravity is obtained for each group, a non-standard temporary center of gravity is deleted from the obtained temporary center of gravity, and further left By creating a group of three temporary centroids from the temporary centroids, finding a new temporary centroid for each group, and repeating this to obtain the centroid of the outer circle, so that a conventional operator can It is possible to eliminate the problems of determining a circular boundary portion and performing manual measurement, or inaccurate detection of the boundary portion imaged at the measurement site, and accurately obtaining the center of gravity.

  After obtaining the center of gravity of the outer circle as described above, the center of gravity of the inner circle is next obtained. FIG. 21 shows a flow for obtaining the center of gravity of the inner circle. After the start (U-1), an outer circle is formed (U-2). The outer circle is formed from the image shown in FIG. 13C used when detecting the edge of the outer circle. After forming the outer circle, an edge detection range is set from the center of gravity of the outer circle toward the outer circle (U-3). FIG. 22 shows a method for setting the edge detection range in this case.

  FIG. 22 is a diagram in which edges are emphasized, and the setting of the edge detection range of the inner circle is such that the line segments 87a, 87b, 87c are radiated from the center of gravity 86 of the outer circle to the outer circle 69 determined above. Provided (in the case of FIG. 22, the total number of line segments is 16), fan-shaped edge detection ranges 88-1, 88-2, 88-3, surrounded by an outer circle 85 and line segments 87a, 87b, 87c. .. Are set (in the case of FIG. 22, 16 edge detection ranges are set). The edge detection range is not limited to 16, but is preferably provided as appropriate by changing the number of line segments.

  FIG. 23 shows an example of one edge detection range 88-1 of the set 16 edge detection ranges shown in FIG. 65 in the edge detection range 88-1 is a part of PS, 66 is an R layer, 67 is a G layer, 68 is a B layer, and 86 is the center of gravity of the outer circle. Reference numeral 69 denotes a boundary between a BM (not shown) and a part 65 of the PS, and in this case, an outer circle. Reference numeral 70 is a boundary between the PS portion 65 and the R layer 66, 71 is a boundary between the R layer 66 and the G layer 67, and 72 is a boundary between the G layer 67 and the B layer 68.

As the edge used for obtaining the center of gravity of the inner circle, the Nth edge detected in advance from the outer circle toward the center of gravity 86 of the outer circle in the edge detection range is used. In the embodiment of the present invention, N = 1, and therefore, the first edge 70 from the outer circle 69 is used. Edge detection is performed along the line segment 89 from the edge detection range 88-1 toward a center of gravity 86 of the outer circle from a part 69a of the outer circle 69 indicated by 88-1, for example (U-4). In the embodiment of the present invention, a case where one edge along the line segment 89 is detected in one edge detection range 88-1 will be described as an example. However, the present invention is not limited to this. A plurality of line segments may be provided and a plurality of edges may be detected from one edge detection range.

  In order to detect the edge toward the inner side from the outer circle, as in the case of the edge detection of the outer circle described above, it is possible to detect the edge by using a binarization method or a shading method which is generally performed. I can do it.

  Edge detection is performed for all 16 edge detection ranges 88-1, 88-2, 88-3 to 88-16 shown in FIG. FIG. 24 is a diagram schematically showing the obtained edge. The edges shown in FIG. 23 are the edge 90-1 obtained from the edge detection range 88-1, and similarly the edge 90-2 to edge 90- obtained from the edge detection range 88-2 to edge detection range 88-16. 16 is shown.

  A means for obtaining the temporary center of gravity of the inner circle from the 16 detected edges after the edge of the inner circle is detected will be described. In order to obtain the temporary center of gravity of the inner circle, first, a group of three edges is created (U-5). To create a group, first select an edge. In selecting an edge, a group of edges for each of the three edge detection ranges is determined in advance according to the number of edge detection ranges in the same manner as when the edge of the outer circle is obtained. That is, a group of three edges is formed among the 16 edges obtained from the 16 edge detection ranges shown in FIG. Three edges are selected so that a triangle formed by three edges is a triangle having no obtuse angle. For example, in the case of 16 divisions as in the embodiment of the invention, a group is created for every three edges such as (first, sixth, eleventh) and (second, seventh, twelfth). The temporary center of gravity is obtained from the three edges for each group. The (first, sixth, eleventh) edges refer to the obtained edges 90-1, 90-6, 90-11 shown in FIG. The (second, seventh, twelfth) edges refer to the determined edges 90-2, 90-7, 90-12 shown in FIG. Similarly, (third, eighth, thirteenth), (fourth, ninth, fourteenth), (fifth, tenth, fifteenth) groups are created to create a total of five groups.

  In the example of this embodiment, since 16 edges are detected, the above five groups are created, and the edges 90-16 are not selected. If there are 19 detected edges, 6 groups are created from 18 edges, and the remaining 1 edge is not selected.

  Temporary centroids are obtained for all groups of the three selected edges (U-6). The temporary centroid can be obtained using a geometric method in the same manner as the provisional centroid of the outer circle, and the five centroid coordinates (Xin1, Yin1), (Xin2, Yin2), ( Xin3, Yin3), (Xin4, Yin4), (Xin5, Yin5) are obtained. (Xout21, Yout21) may be regarded as (0.0) by the center of gravity of the obtained outer circle.

  Non-standard temporary centroids are deleted from the five temporary centroids having the determined centroid coordinates Xin1, Yin1), (Xin2, Yin2), (Xin3, Yin3), (Xin4, Yin4), (Xin5, Yin5) (U -7). FIG. 26 shows a case where non-standard temporary centroids (Xin2, Yin2) are deleted from five temporary centroids (the non-standard temporary centroids here are all detected as in the case of the temporary centroid of the outer circle). The standard is obtained from the value of the temporary center of gravity, and the temporary center of gravity deviating from the standard is indicated.

The method for obtaining the standard of the temporary center of gravity outside the standard is performed in the same manner as the case of obtaining the standard of the temporary center of gravity of the outer circle. A new temporary center of gravity is obtained again from the remaining temporary center of gravity after deleting the non-standard temporary center of gravity (U-8). The method for obtaining a new temporary center of gravity again from the temporary center of gravity remaining after deleting the non-standard temporary center of gravity is performed in the same manner as when the new temporary center of gravity is obtained again from the temporary center of gravity of the outer circle (S-8). In this way, the temporary center of gravity is obtained from the temporary center of gravity of every group (U-9). In order to obtain a new temporary center of gravity from the temporary center of gravity of every group, the same process as in the case of obtaining a new temporary center of gravity from the temporary center of gravity of every group (S-9) is performed. Until the number of temporary centroids becomes one or two (in the case of (U-10) NO), a new temporary centroid is obtained from the remaining temporary centroids, and finally the temporary centroids become one or two. For example, when there is one temporary center of gravity (one case of (U-10)), the temporary center of gravity is set as the center of gravity of the inner circle (U-11), and the process ends (U-14).

  If there are two provisional centroids (two cases (U-10)), the two centroids are averaged (U-12) to be the center of gravity of the inner circle (U-13), and the process ends (U- 24). FIG. 27 shows the new provisional center of gravity (Xin11, Yin11) 92 and the center of gravity (Xin21, Yin21) 93 of the determined inner circle.

  From the coordinates of the obtained outer circle center of gravity (Xout21, Yout21) and the coordinates of the inner circle center of gravity (Xin21, Yin21), | Xout21−Xin21 | = X and | Yout21−Yin21 | = Y are obtained and X and Y are positioned. This is the amount of deviation.

  In this way, as in the case of obtaining the center of gravity of the outer circle, a group of three edges selected from a plurality of edges of the inner circle is created, and a temporary center of gravity is obtained for each group, The temporary center of gravity out of the standard is deleted, and a group of three temporary centers of gravity is created from the remaining temporary centers of gravity. A new temporary center of gravity is obtained for each group, and this is repeated until the center of gravity of the inner circle is obtained. By obtaining, it becomes possible to accurately obtain the center of gravity.

  When the obtained positional deviation amounts X and Y of the outer circle and the inner circle are any of X ≧ Xs and Y ≧ Ys with respect to the predetermined threshold values Xs and Ys, the outer circle and the inner circle are displaced. An alarm signal that is regarded as defective is generated and fed back to the manufacturing process to adjust and maintain the manufacturing apparatus that is considered to be the cause of the defect.

  In the embodiment of the present invention, a part of PS and an R layer are taken as an example of a two-layer circle. However, the present invention is not limited to this, and any two layers of a part of PS, an R layer, a G layer, or a B layer are used. This can be applied to the measurement of misalignment. Further, the present invention is not limited to the color filter substrate, and can also be applied to the measurement of a circular positional deviation having two or more layers as a whole.

  In the conventional method, the boundary between the edges could not be detected stably, so there was variation in the measurement of the two-layer circular displacement. However, according to the two-layer circular misalignment measuring apparatus of the present invention, the center of gravity of each of the two-layer circles can be obtained stably, so that measurement without variation is possible. In addition, when the calculated amount of misalignment of the two-layer circle exceeds a threshold value, it is expected to suppress the occurrence of defective products by issuing an alarm and feeding back to the manufacturing process.

10 ... Glass substrate 11 ... Black matrix (BM)
12a ... Red R colored layer 12b ... Green G colored layer 12c ... Blue B colored layer 13 ... Transparent electrode 14 ... Photospacer (PS)
14a: Part of PS 14b: Part of PS 15: Part surrounded by broken line 16: Red colored photoresist layer (R layer)
17 ... Green colored photoresist layer (G layer)
18 ... Blue colored photoresist layer (B layer)
20 ... 2 layers below 21 ... 2 layers above 22 ... PS
23 ... Colored layer 24 ... Outer circumference of PS 25 ... Boundary 30 between PS and colored layer ... Glass substrate 31 ... BM
32 ... R pixel 33 ... B pixel 35 ... PS part 36 ... R layer 37 ... G layer 38 ... B layer 39 ... PS part 40 ... PS
41 ... Color filter substrate 42 ... Measurement stage 43 ... Imaging unit 44 ... Control unit 45 ... X-axis drive unit 46 ... Y-axis drive unit 47 ... Z-axis drive unit 51 ... BM
52 ... R pixel 53 ... G pixel 54 ... B pixel 55 ... outer circle 56 ... inner circle 57 ... center of gravity of outer circle (Xout, Yout)
58 ... Position of the center of gravity of the inner circle (Xin, Yin)
59 ... Inspection area 60 ... Outside of inspection area 61 ... Center 62a, 62b, 62c of inspection area ... Line segments 63-1, 63-2, 63-3 to 63-16 ... Edge detection range 64 ... BM
65 ... PS part 66 ... R layer 67 ... G layer 68 ... B layer 69 ... Boundary (outer circle) between BM64 and PS part 65
69a: Some points 70 of the outer circle 70: A boundary 71 between the PS portion 65 and the R layer 66 ... A boundary 72 between the R layer 66 and the G layer 67 ... A G layer 67 and a B layer 68 Boundary 83-1, 83-2, 83-3 to 83-16 ... Edge 84 obtained from edge detection range ... Permissible range 85 of the provisional center of gravity of outer circle ... Newly obtained Temporary center of gravity 86 of outer circle ... Centroids 87a, 87b, 87c of outer circle obtained ... Radial line segments 88-1, 88-2, 88-3 to 88-16 ... edge Detection range 89 ... line segment 90-1, 90-2 to 90-16 ... detected edge 91 of inner circle ... allowable range 92 of provisional center of gravity of inner circle ... new request Temporary center of gravity 93 of the inner circle determined ... Center of gravity of the inner circle determined

Claims (12)

  Imaging means for imaging a circular object having two or more layers as a whole from above, means for setting the inspection area and the center of the inspection area from the image obtained by the imaging means, and a plurality of outer circles in the inspection area Means for setting an edge detection range of the outer circle, means for detecting a plurality of edges of the outer circle from a plurality of edge detection ranges of the outer circle, means for determining a temporary center of gravity of the outer circle from the plurality of edges of the outer circle, and an outer circle Means for determining the center of gravity of the outer circle from the temporary center of gravity, means for determining the plurality of edge detection ranges of the inner circle from the center of gravity of the outer circle and the outer circle, and the plurality of edges of the inner circle from the plurality of edge detection ranges of the inner circle. Means for detecting, means for determining the temporary center of gravity of the inner circle from a plurality of edges of the inner circle, means for determining the center of gravity of the inner circle from the temporary center of gravity of the inner circle, and the center of gravity of the outer circle and the center of gravity of the inner circle and the outer circle Inner circle position 2-layer circular positional deviation measuring apparatus comprising the means for calculating is amount.   The means for setting the inspection area and the center of the inspection area sets the center of the inspection area and the inspection area by pattern matching of a pre-registered matching and an image picked up by the image pickup means. Two-layer circular displacement measuring device.   The means for setting a plurality of edge detection ranges of the outer circle is provided with a plurality of line segments from the outside of the inspection area toward the center of the inspection area, and a plurality of lines provided toward the outside of the inspection area and the center of the inspection area. 3. The two-layer circular misregistration measuring apparatus according to claim 1, wherein a range surrounded by the line segment is an edge detection range.   The means for detecting a plurality of edges of the outer circle is defined as an edge of the outer circle, which is the Nth edge detected from the outside in the edge detection range, and the edge from a part of the outside of the detection area toward the center of the inspection area 4. The two-layer circular position measuring device according to claim 1, wherein detection is performed.   The means for obtaining the provisional center of gravity of the outer circle provides a group of three edges from a plurality of edges of the obtained outer circle, and obtains the provisional center of gravity of the same number of outer circles as the number of groups. The two-layer circular misregistration measuring apparatus according to any one of 1 to 4.   The means for determining the center of gravity of the outer circle is to remove the non-standard temporary center of gravity from the plurality of temporary centers of gravity obtained for the outer circle, create a group of three temporary centers of gravity from the remaining temporary centers of gravity, and the same number as the number of groups The new temporary center of gravity is calculated, and further new temporary centers of gravity are obtained until the total of the calculated new temporary center of gravity and the temporary center of gravity not included in the group becomes three or less. When the total of the temporary centroids that do not enter is two, the two centroids are averaged to be the center of the outer circle, and when the total is one, the temporary centroid is the center of the outer circle. Item 6. The two-layer circular misalignment measuring device according to any one of Items 1 to 5.   The means for setting a plurality of edge detection ranges of the inner circle is provided with a plurality of line segments from the center of gravity of the outer circle toward the outer circle, and a range surrounded by the plurality of line segments and the outer circle is defined as an edge detection range of the inner circle. The two-layer circular misregistration measuring apparatus according to any one of claims 1 to 6, wherein:   The means for detecting a plurality of edges of the inner circle is the edge of the inner circle that is the Nth edge detected from the outer circle in the edge detection range of the inner circle, and the center of gravity of the outer circle is determined from some points of the outer circle. 8. The two-layer circular misregistration measuring apparatus according to claim 1, wherein edge detection is performed toward the front. The means for obtaining the provisional center of gravity of the inner circle forms a group of three edges from the obtained edges of the plurality of inner circles, and obtains the provisional center of gravity of the same number of inner circles as the number of groups. The two-layer circular misalignment measuring apparatus according to any one of 1 to 8.   The means for calculating the center of gravity of the inner circle deletes the non-standard temporary center of gravity from the plurality of temporary centers of gravity determined for the inner circle, provides three temporary center of gravity groups from the remaining temporary center of gravity, and has the same number as the number of groups The new temporary center of gravity is calculated, and further new temporary centers of gravity are obtained until the total of the calculated new temporary center of gravity and the temporary center of gravity not included in the group becomes three or less. When the total of the temporary centroids not included is two, the two temporary centroids are averaged to be the center of the outer circle, and when the total is one, the temporary centroid is the center of the inner circle. Item 10. The two-layer circular misalignment measuring device according to any one of Items 1 to 9.   The means for calculating the amount of displacement calculates │Xout-Xin│, │Yout-Yin│ from the determined center of gravity coordinates (Xout, Yout) of the outer circle and the determined center of gravity coordinates (Xin, Yin) of the inner circle. The two-layer circular misregistration measuring apparatus according to any one of claims 1 to 10, wherein:   The threshold value of the positional deviation amount between the outer circle and the inner circle is set in advance, and an alarm signal is generated and fed back to the manufacturing process when the calculated positional deviation amount exceeds the threshold value. The two-layer circular misalignment measuring device according to any one of 11.

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