JP2006047170A - Apparatus for inspecting irregularities in periodic pattern, and method for inspecting irregularities in periodic pattern using same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus and method for inspecting irregularities in a periodic pattern, capable of stably and precisely detecting the irregularities of the periodic pattern. <P>SOLUTION: The apparatus for inspecting the irregularities of the periodic pattern is equipped with an imaging section (10), having at least a means for imaging an image; an XY stage (20), on which an object substrate to be inspected is mounted and which has a means for driving it in the X-axis and Y-axis directions; an illumination section (30) having a means for illuminating the object substrate to be inspected; an optical filter changing section (40a, 40b) which sets optical filters at the illumination section and/or the photographing section, in order to regulate their optical characteristics and which has a means of enabling the optical filters to be changed; and a section (60) for controlling the apparatus. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a product unevenness inspection apparatus having a periodic pattern and a periodic pattern unevenness inspection method using the device.

As an industrial product having a periodic pattern in which a fine pattern as a unit is repeated, an aperture grill built in a cathode ray tube of a color television, or a liquid crystal substrate on which a black matrix and a color filter for a color liquid crystal television are formed. Etc.
In the case of a product having these periodic patterns, there is a problem that pattern irregularities occur partially or entirely due to variations in process conditions and temperature / humidity during the manufacturing process, resulting in a reduction in product quality.

An example of a conventional periodic pattern unevenness inspection apparatus is shown in FIG. This is because the CCD camera (imaging means) 112 is scanned with the width of the pattern in the pixel column direction when the object W formed repeatedly in the width direction is imaged and inspected under transmitted illumination. Adjust the direction and set the imaging means to just focus, and shift the relative position between the imaging means and the target object under the condition that all patterns once fit in the field of view of one pixel over the entire width. An image is captured, and the image processing unit 114 divides these by the light source image to create a transmittance image by shifting the position, and the maximum luminance value among the pixels having the same coordinates in the total transmittance image is determined. A nonuniformity inspection method has been proposed in which a maximum value image is used as a value, and an inspection is performed based on a pattern image created by extracting only pixels corresponding to the entire pattern width from the image (see, for example, Patent Document 1).
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In this method, unevenness is extracted and inspected by devising a processing method from an image having low contrast between the uneven portion and the normal portion.
JP 2002-148210 A

  However, in the above prior art, for example, in imaging of black matrix unevenness, particularly unevenness of a black matrix having a large opening, it is not possible to improve the contrast between the uneven portion and the normal portion, and even if the processing is devised, the original image Since the contrast is low, it can only achieve inspection ability below visual sensory inspection.

  The present invention has been made in view of the above problems, and an object thereof is to provide a periodic pattern unevenness inspection apparatus and a periodic pattern unevenness inspection method capable of stably and accurately detecting pattern unevenness of a pattern having periodicity. And

In order to achieve the above object in the present invention, first, in claim 1, an imaging unit (10) having at least a means for imaging an image and a substrate to be inspected are placed, and X-axis and Y-axis directions are placed. An XY stage (20) having means for driving the light source, an illuminating part (30) having means for illuminating the substrate to be inspected, and an optical filter for limiting optical characteristics are placed on the illuminating part and / or the imaging part An optical filter changer unit (40a, 40b) having means capable of switching optical filters, an image processing unit (50) for processing an image captured by the imaging unit, the imaging unit, an XY stage, and an illumination A periodic pattern non-uniformity inspection apparatus comprising an apparatus control section (60) for managing and controlling the optical section, the optical filter changer section, and the image processing section.

  The periodic pattern according to claim 1, wherein a set of two filters having a complementary color relationship is placed on the optical filter changer section (40a, 40b). This is a non-uniformity inspection apparatus.

  Furthermore, in claim 3, there is provided an inspection method for inspecting pattern unevenness of a periodic pattern imaged by the imaging unit (10) using the periodic pattern unevenness inspection apparatus according to claim 1 or 2. The pattern image passing through a pair of two optical filters having complementary colors in the optical filter changer unit is captured by the image capturing unit (10), and the image processing unit (50) captures the pattern image between the two pattern images. The periodic pattern unevenness inspection method is characterized by detecting pattern unevenness of a periodic pattern by performing image processing.

According to the periodic pattern unevenness inspection apparatus and method of the present invention, only the periodic pattern unevenness can be detected stably and with high accuracy.
Furthermore, since the image after the image processing is an image in which unevenness is emphasized, it can be used as a monitor device for visually checking the uneven state of the substrate to be inspected.

Hereinafter, embodiments of the present invention will be described.
As shown in FIG. 1, the periodic pattern unevenness inspection apparatus 100 of the present invention includes an imaging unit 10, an XY stage unit 20, an illumination unit 30, and an optical filter for capturing a pattern image of an inspection target substrate 61. An optical filter changer unit 40 that can be switched, an image processing unit 50 that processes captured images, and an apparatus control unit 60 that controls the entire apparatus are configured.

As the imaging unit 10, a CCD camera or the like equipped with a solid-state imaging device can be used.
As the XY stage section 20, a normal XY stage equipped with a pulse drive motor and equipped with a position control mechanism can be used.
The illumination unit 30 is composed of a plurality of illumination units whose illumination directions can be changed in any direction, and the number of illumination units installed can be appropriately set depending on the size of the inspection target substrate.

  The optical filter changer unit 40 is provided between the illumination unit 30 and the inspection target substrate 61 and between the imaging unit 10 and the inspection target substrate 61. The optical filter changer unit 40 has a set of two optical filters in a complementary color relationship. The group is placed, and each optical filter is set with the contents programmed in advance by the apparatus control unit 60.

  The image processing unit 50 uses the two optical filters (for example, green and magenta, red and cyan, and blue and yellow) that are complementary to each other to form two sets of pattern images captured by the imaging unit 10. 50, and processing between pattern images (for example, difference processing) can obtain an image in which uneven portions due to periodic pattern fluctuations are emphasized. Based on the image in which uneven portions are emphasized, Uneven portion extraction processing and determination processing are performed.

  The apparatus control unit 60 programs an inspection procedure as an inspection apparatus in advance, and according to the contents of the program, from the apparatus control unit 60, the imaging unit 10, the XY stage unit 20, the illumination unit 30, the optical filter changer unit 40, and A control signal is sent to the image processing unit 50 so that a series of inspections can be performed.

  The periodic pattern unevenness inspection method of the present invention will be described with reference to the inspection apparatus 100 of FIG. 1. Illumination light from the illumination unit 30 passes through a pair of optical filters in a complementary color relationship of the optical filter changer unit 40a. Then, the inspection target substrate 61 on the XY stage 20 is irradiated and two pattern images are picked up by the image pickup unit 10. Further, the two pattern images picked up by the image pickup unit 10 are captured by the image processing unit 50 and subjected to processing (for example, difference processing) between the pattern images. It is designed to be displayed on the display.

  As described above, the periodicity pattern of the substrate to be inspected is imaged through a pair of optical filters having a complementary color relationship, and the two pattern images are processed between the images by the image processing unit 50, whereby the periodicity is obtained. An image in which uneven portions due to pattern fluctuations are emphasized is obtained.

  Further, as a method of imaging the periodic pattern of the inspection target substrate through a pair of optical filters having a complementary color relationship, an optical filter is set in the optical filter changer unit 40b between the imaging unit 10 and the inspection target substrate. Without setting the optical filter in the optical filter changer unit 40 a between the illumination unit 30 and the inspection target substrate 61 and imaging the periodic pattern of the inspection target substrate, and between the illumination unit 30 and the inspection target substrate 61. A method of setting the optical filter in the optical filter changer unit 40b between the imaging unit 10 and the inspection target substrate without setting the optical filter in the optical filter changer unit 40a, and imaging the periodic pattern of the inspection target substrate, and the illumination unit 30 and the optical filter changer unit 40a between the inspection target substrate 61 and the imaging unit 10. There are three methods of a method of imaging a periodic pattern of the inspection target board respectively to the optical filter changer unit 40b sets the optical filter between 査 target substrate.

A method for inspecting pattern unevenness of a substrate to be inspected using the periodic pattern unevenness inspection apparatus 100 of the present invention will be described.
First, an inspection target substrate (for example, a liquid crystal substrate having a periodic black matrix pattern) is placed on the XY stage unit 20 of the periodic pattern unevenness inspection apparatus 100.
Next, the illumination light from the illumination unit 30 is irradiated onto the inspection target substrate by the filter illumination light that has passed through a pair of optical filters in a complementary color relationship of the optical filter changer unit 40, and is taken into the imaging unit 10 as a pattern image. It is.

  Next, a pattern image picked up by the image pickup unit 10 using two optical filters (green and magenta, red and cyan, and blue and yellow) having a complementary color relationship is captured by the image processing unit 50, and two sheets are obtained. By performing the difference processing on the pattern image, it is possible to obtain an image in which the unevenness due to the fluctuation of the periodic pattern is emphasized.

  Further, extraction processing and determination processing are performed based on an image in which the unevenness portion is emphasized, and are displayed by the processing unit 50 and the device control unit 60.

  A series of instructions and operation control associated with the inspection are programmed and are controlled by the apparatus control unit 60.

It is a schematic block diagram which shows one Example of the periodic pattern nonuniformity inspection apparatus of this invention. It is a schematic block diagram which shows an example of the conventional periodic pattern nonuniformity inspection apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Imaging part 20 ... XY stage 30 ... Illumination part 40a, 40b ... Optical filter changer part 50 ... Image processing part 60 ... Apparatus control part 61 ... Inspection object board 110 ... Stage 112 ... CCD Camera 114 …… Image processing unit 116 …… Camera controller 118 …… Light source controller 120 …… Device control unit 122 …… Object position shifting unit 124 …… Camera position shifting unit

Claims (3)

  An imaging unit (10) including at least an image capturing unit, an XY stage (20) including a unit on which an inspection target substrate is mounted and driven in the X-axis and Y-axis directions, and illumination of the inspection target substrate And an optical filter changer unit (40a, 40a, having an illuminating unit (30) having an optical filter and means for mounting an optical filter for limiting optical characteristics on the illuminating unit and / or the imaging unit and capable of switching the optical filter. 40b), an image processing unit (50) that processes an image captured by the imaging unit, and a device control unit (60) that manages and controls the imaging unit, XY stage, illumination unit, optical filter changer unit, and image processing unit. And a periodic pattern nonuniformity inspection apparatus.   2. The periodic pattern unevenness inspection apparatus according to claim 1, wherein a set of two filters each having a complementary color relationship is placed on the optical filter changer section (40 a, 40 b).   An inspection method for inspecting pattern unevenness of a periodic pattern imaged by the imaging unit (10) using the periodic pattern unevenness inspection apparatus according to claim 1 or 2, wherein the optical filter changer unit has a complementary color relationship. A periodic pattern is obtained by picking up a pattern image that passes through a set of two optical filters in the image pickup unit (10) and performing image processing between the two pattern images in the image processing unit (50). A periodic pattern unevenness inspection method characterized by detecting a pattern unevenness.

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