JP4104366B2 - Synthetic pattern inspection method and apparatus - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a composite pattern inspection method and apparatus, and more particularly, to a composite pattern inspection method and apparatus suitable for inspection of a product in which a composite pattern having a shape in which a plurality of element patterns are connected is arranged.
[0002]
[Prior art]
FIG. 10 (A), the case of one type in (B) and 2 types of an example of a case as shown respectively, one or more "element patterns" is disposed in contact with linearly continuous to and (continuous contact There is a product (work) in which one “composite pattern” formed in a shape is disposed. FIG. 11 shows an image of a part of a plan view of a work in which composite patterns are regularly arranged in the case of two types of element patterns. Examples of such a workpiece include a universal substrate and a seal substrate that are used for trial production of an electric circuit in which synthetic patterns having the same shape are arranged.
[0003]
When the workpiece as shown in FIG. 11 is manufactured, it is necessary to inspect whether or not a defect as shown in FIG. As a method for inspecting these defects, visual inspection, visual inspection of a workpiece, image input by an imaging means, inspection by a constant pitch comparison method for comparing pixel values at a certain pitch for the input inspection image, and inspection are also performed. An inspection by labeling is known in which an image area corresponding to a composite pattern is labeled in units of images, and comparison is performed in units of labeling areas.
[0004]
[Problems to be solved by the invention]
However, in the case of the visual inspection, if the size of the element pattern is reduced, there is a limit to performing a complicated shape such as a composite pattern by visual inspection, and it is difficult to satisfy the required accuracy. In particular, as shown in the image of FIG. 13, it is difficult to inspect a minute defect near the connection portion of the element pattern.
[0005]
Further, in the case of the inspection by the constant pitch comparison method, as shown on the right side in FIG. 14A, an example of output when the line sensor camera scans the straight line L, the layout of the composite pattern is completely regulated. In such a case, there is no problem because it is possible to determine pass / fail by comparing the luminance values between pixels that are spaced apart by a certain distance. However, as shown in FIGS. In the case of a gradual change, there is a problem that a defect smaller than the change in pitch and size cannot be detected and cannot be applied.
[0006]
Furthermore, in the inspection by the labeling, when a defect is detected by the difference or ratio of the areas of neighboring composite patterns after the labeling, the defect size (allowable range) can be relatively detected when the area of one composite pattern increases. ) Also increases, and local thickening and thinning as shown in the image of FIG. 15 are less likely to appear as a difference in area, so that it is difficult to detect local defects. In addition, when a defect is detected by difference processing or exclusive OR, when overlapping with neighboring composite patterns, if the size of one composite pattern increases, even non-defective products can be completely overlapped. There is a problem that it becomes difficult and is likely to cause pseudo defects.
[0007]
The present invention has been made to solve the above-described conventional problems, and the arrangement and constituent elements of a composite pattern for a workpiece in which a composite pattern having a shape in which a plurality of element patterns are linearly connected is provided. It is an object of the present invention to provide a composite pattern inspection method and apparatus capable of easily and reliably inspecting a composite pattern regardless of the number of patterns.
[0008]
[Means for Solving the Problems]
According to the present invention, an image of an inspection object in which a composite pattern having a shape in which a plurality of element patterns are connected linearly or with a curvature is disposed is input by an imaging unit, and the composite pattern is based on the input inspection image. A method for inspecting a composite pattern, wherein a predetermined size including only one element pattern region is cut out as a unit image from a combined pattern region on an input inspection image, and based on the cut out unit image The problem is solved by inspecting the composite pattern.
[0009]
The present invention also inputs an image of an inspection object in which a composite pattern having a shape in which a plurality of element patterns are connected in a straight line or with a curvature is provided by an imaging unit, and based on the input inspection image, A composite pattern inspection apparatus for inspecting a composite pattern, a unit for cutting out a predetermined size including only one element pattern region as a unit image from a composite pattern region on an input inspection image, and a cut unit The above problem is similarly solved by providing a means for inspecting the composite pattern based on an image.
[0010]
That is, in the present invention, a predetermined size including the element pattern region is cut out as a unit image from the combined pattern region on the input inspection image, and the combined pattern is inspected based on the cut out unit image. As a result, it is possible to compare the element patterns constituting the composite pattern as a unit, so that even a small defect can be easily and surely affected without being affected by the arrangement position and the number (area) of the element patterns. Can be detected.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0012]
FIG. 1 is a schematic perspective view showing an appearance of an inspection apparatus according to an embodiment of the present invention, and FIG. 2 is a block diagram showing an outline of the control system.
[0013]
The inspection apparatus of this embodiment includes a table 10 on which a work (inspection object) W is placed, a line sensor camera (imaging means) 12 that is an image input unit disposed above the table 10, and the camera 12. Is input to a biaxial transport unit 14 that can move in the X direction and the Y direction with respect to the table 10, and a transmission illumination unit (not explicitly shown in FIG. 1) 16 built in the table 10. An image processing unit 18 having a function of performing image processing for defect inspection, which will be described later, on the basis of the inspection image, and a control unit 20 including a computer for controlling the operation of each of these units are provided. Note that the image processing unit 18 is actually included in a computer constituting the control unit 20. The imaging means may be an area sensor camera.
[0014]
Workpiece W to be inspected of the present embodiment, FIG. 10 synthetic pattern two component patterns shown in (B) is connected in a straight line is predetermined sheet metal, as shown in FIG. 11 It is repeatedly arranged as a through hole over a range. Therefore, in the present embodiment, the transmitted light when the work W is illuminated from the back side is captured by the camera 12 by the transmitted illumination unit 16 in the table 10, and the inspection image of the composite pattern is input as the transmitted light image. It has become. However, in the following description, for convenience, an image area corresponding to a composite pattern and an element pattern that are light-transmitting portions is illustrated as a dark portion, and a background portion that is a light-shielding portion is illustrated as a bright portion.
[0015]
Next, the operation of this embodiment will be described with reference to the flowchart of FIG.
[0016]
First, the line sensor camera 12 captures a workpiece W and inputs a predetermined range of inspection image (step 1), and the input inspection image is labeled with the same number in a continuous high-brightness image region. As shown in FIG. 4A, a labeled image obtained by extracting an image area (synthetic pattern area) corresponding to the synthesized pattern on the image is created (step 2 ).
[0017]
Next, the labeling image is cut at an appropriate position to form a unit image that is substantially the same as the image region (element pattern region) corresponding to the element pattern constituting the composite pattern as shown in FIG. As shown in FIG. 5C, an inspection process for comparing unit images between element patterns having the same shape is performed (step 4), and the result is output (step 5). If the inspection of the entire surface of the workpiece W is completed, the process is terminated. If the inspection is left, the camera is moved to that position, and the same process is repeated (steps 6 and 7).
[0018]
The step 3 will be described in detail. When a unit image is cut out by cutting the combined pattern area into element pattern areas, the following method is used.
[0019]
(1) As shown in FIG. 5, when the size of the element pattern is constant, by registering the size a and b set in advance in each of the element patterns A and B and the arrangement rule, Disconnect according to the registered data.
[0020]
(2) As indicated by a broken line in FIG. 6A, the luminance value in the rectangle circumscribing the combined pattern region (the luminance value related to the combined pattern region) is the same direction as the direction to be cut (the direction orthogonal to the connecting direction). ) Is integrated (integrated) to create the projection data shown in FIG. 5B, and the contact points of the element pattern are obtained from the extreme values of the data, and at the positions of the extreme values as shown in FIG. By cutting, a unit image is cut out by being surely divided into individual element patterns as shown in FIG. This method can also be applied when the dimensions of all element patterns are not the same.
[0021]
As described above, the unit pattern is created by dividing the composite pattern area into the respective element pattern areas as shown in FIG. 4C, so that the exclusive logic of the unit image is obtained for each element pattern of the same shape. It becomes possible to take the sum. Therefore, if there is a protrusion-like defect on one side as shown in FIG. 7A, the defect can be detected as shown in FIG. 7B.
[0022]
Further, in the present embodiment, when considering a defect near the cutting position, that is, the connection position of the element pattern, by overlapping the vicinity area of the cutting portion as described below, the element pattern constituting the composite pattern is It is also possible to prevent a decrease in detection sensitivity when there is a defect near the connection position.
[0023]
As shown in the image of FIG. 8A, when the defect of the minimum size is near the cutting position (dashed line position) of the element pattern, the defect is also cut and divided. Further, if the size after division is smaller than the minimum detectable size, the defect may not be detected because it disappears in post-processing including noise removal by image expansion / contraction processing. Therefore, even if the cut part is overlapped to cope with it, if the defect is close to the minimum detectable defect size as shown in FIG. Since the defect size is further reduced, it cannot be detected.
[0024]
Therefore, as shown in FIG. 3C, the overlap amount is set to be equal to or larger than the minimum detectable defect size. That is, the unit image is cut out to a predetermined size obtained by adding the minimum defect size detectable to the size of the element pattern region. By doing so, even when the defect is divided, the defect always remains in a size that can be detected in both.
[0025]
According to the present embodiment described in detail above, it is possible to accurately inspect the composite pattern, which is difficult with visual inspection. In addition, by completing the comparison process between element patterns in one composite pattern, even if the pitch of the layout of the composite pattern and the size of the element pattern differ between the composite patterns, it is affected. Can be accurately inspected.
[0026]
Although the present invention has been specifically described above, the present invention is not limited to that shown in the above embodiment, and various modifications can be made without departing from the scope of the invention.
[0027]
For example, the specific configuration of the inspection apparatus according to the present invention is not limited to that shown in the embodiment.
[0028]
Further, the composite pattern to be inspected according to the present invention is not limited to the element pattern as shown in FIG. 9A, which is shown again, but as shown in FIG. Needless to say, they may be connected with an arbitrary curvature. Further, there may be three or more element patterns, and the arrangement of the composite pattern may be random.
[0029]
【The invention's effect】
As described above, according to the present invention, regarding an inspection object on which a composite pattern in which a plurality of element patterns are connected in a straight line is provided, regardless of the layout of the composite pattern, the number of constituent patterns, and the like. Therefore, the composite pattern can be inspected easily and reliably.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view showing an appearance of an inspection apparatus according to an embodiment of the present invention. FIG. 2 is a block diagram showing an outline of a control system of the inspection apparatus. 4 is an explanatory diagram showing the characteristics of the inspection method of the embodiment. FIG. 5 is an explanatory diagram showing a method for dividing a composite pattern. FIG. 6 is an explanatory diagram showing another method for dividing the composite pattern. FIG. 8 is an explanatory diagram illustrating a method of dividing a composite pattern when considering a defect at a cut portion. FIG. 9 is an explanatory diagram illustrating an example of a composite pattern to be inspected according to the present invention. FIG. 10 is an explanatory diagram showing the relationship between element patterns and composite patterns. FIG. 11 is an explanatory diagram showing an image of a work on which composite patterns are arranged. FIG. 12 is an explanatory diagram showing examples of defects occurring in the composite patterns. [Figure 13] Missing visual inspection Explanatory view showing a [14] and features of the examination by the constant pitch comparison method, EXPLANATION OF REFERENCE NUMERALS illustration showing a problem of the inspection by the illustration Figure 15 labeling showing a problem
W ... Work 10 ... Table 12 ... Image input unit 14 ... Conveying unit 16 ... Illuminating unit 18 ... Image processing unit 20 ... Control unit

Claims (5)

A composition in which an object to be inspected in which a composite pattern having a shape in which a plurality of element patterns are connected linearly or with a curvature is arranged is input by an imaging means, and the composite pattern is inspected based on the input inspection image A pattern inspection method,
A predetermined size including only one element pattern area is cut out as a unit image from the combined pattern area on the input inspection image,
A synthetic pattern inspection method, comprising: inspecting the synthetic pattern on the basis of a cut unit image.   The method for inspecting a composite pattern according to claim 1, wherein when the composite pattern is inspected based on the cut-out unit image, unit images including the same element pattern are compared.   2. The unit pattern area is divided into element pattern areas based on a size in a connecting direction of element patterns and an arrangement rule of element patterns when a unit image is cut out from the composite pattern area. A method for inspecting a composite pattern described in 1.   When the unit image is cut out from the composite pattern area, the composite pattern area is divided at the position of the extreme value in the projection data obtained by integrating the luminance values related to the composite pattern area in a direction orthogonal to the connecting direction of the element patterns. The method for inspecting a composite pattern according to claim 1. A composition in which an object to be inspected in which a composite pattern having a shape in which a plurality of element patterns are connected in a straight line or with a curvature is arranged is input by an imaging means, and the composite pattern is inspected based on the input inspection image A pattern inspection device,
Means for cutting out a predetermined size including only one element pattern region as a unit image from the combined pattern region on the input inspection image;
An apparatus for inspecting a composite pattern, comprising: means for inspecting the composite pattern based on the cut unit image.

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