JP4858106B2 - Color filter defect inspection method - Google Patents

Description

  The present invention relates to a color filter defect inspection method, and more particularly to a color filter inspection method capable of easily detecting a growth type common defect.

  With the high performance of portable devices and flat-screen TVs, the demand for liquid crystal displays is increasing rapidly, and the demand for cost reduction is increasing. Color liquid crystal displays are made of materials such as glass substrates, liquid crystal materials, polarizing plates, and color filters. Color filters are especially important when high-definition and high-quality displays are required for color liquid crystal displays. Since it is used as a member and accounts for a high percentage of the product price, further price reduction is required.

  The color filter for a liquid crystal display has each colored layer of R / G / B in a region separated by a partition which is a light shielding pattern on a transparent glass substrate (hereinafter referred to as a black matrix or BM in the color filter substrate). It is configured by arranging them.

  Such a color filter for a liquid crystal display is the same in all the color filters manufactured using the same mask due to breakage of the exposure mask or foreign matter adhering to the exposure mask in the manufacturing process. There may be a coordinate defect (hereinafter referred to as a common defect). Various inspection apparatuses for detecting such a common defect are known (for example, see Patent Document 1).

  For example, as shown in the flowchart of FIG. 6, there is a method for detecting a common defect using a defect inspection apparatus using a CCD line sensor. In this method, when a common defect is detected by the defect inspection apparatus, the operator determines whether the defect is a non-defective product / defective product (measures the defect area). The exposure mask is cleaned or replaced with another exposure mask, and the operation of the exposure apparatus is started again after removing the cause of failure.

  An acceptable defect was detected, but a color filter that was determined to be non-defective was registered as a non-defective coordinate for that defect, and in the subsequent inspection of other color filters, a defect with the same coordinate was determined to be a non-defective defect. The flow of the color filter in the inspection process was continued without performing defect removal processing.

However, in such a conventional method, for example, when a defect caused by breakage of the exposure mask due to foreign matter adhered when the colored resin is coated is determined to be a non-defective product, such breakage is not eliminated at all. For this reason, there is a case where such an abnormality of the defect portion spreads as the exposure process is repeated. Such a defect is called a growth type common defect. However, in the above-described conventional method, the growth type common defect is also located at the same coordinate, so that it is determined as a non-defective product, and as a result, a defective product flows out.
JP 2005-128026 A

  The present invention has been made under the above circumstances, and an object thereof is to provide a color filter inspection method capable of easily detecting so-called growth-type common defects.

  In order to solve the above-described problems, the present invention provides a color filter substrate to a defect inspection apparatus, detects a common defect, determines whether the common defect is a non-defective product, and determines whether the common defect is a good product coordinate. A step of registering, a step of recording the number of defective pixels of the common defect registered as non-defective coordinates as a reference common defect pixel number, a set number of color filter substrates are sequentially provided to the defect inspection apparatus, and a common defect that is a non-defective defect is Detecting, counting the number of defective pixels of the common defect, and averaging them to obtain the number of comparison common defect pixels, and the difference between the reference common defect pixel number and the comparison common defect pixel number exceeds a set difference In some cases, a method for inspecting a color filter is provided which includes a step of canceling the non-defective coordinate registration.

  In this case, for the N color filter substrates having the set number, the number of defective pixels of the first substrate to the Nth substrate is averaged to obtain the number of comparison common defective pixels, Each time the inspection of one color filter substrate is completed, the number of defective pixels on the second and subsequent N substrates is averaged to obtain the number of comparative common defective pixels, and the difference between the number of reference common defective pixels and the number of comparative common defective pixels When the difference exceeds the set difference, the non-defective coordinate registration can be canceled at that time.

  According to the present invention, the number of comparison common defective pixels, which is an average value, is obtained for a set number of color filter substrates, and the non-defective coordinate registration is canceled when the difference between the number and the reference common defective pixel number exceeds the set difference. Therefore, it has become possible to easily detect the growth type common defect that has been conventionally overlooked as a non-defective product defect.

  The best mode for carrying out the invention will be described below.

  FIG. 1 is a cross-sectional view showing a method for producing a color filter by a die coating method. In a color filter manufacturing method using a die coating method, a black matrix 2 is usually formed on a glass substrate 1 as shown in FIG. 1A, and then a die coater is used in a region divided by the black matrix 2. A red colored film 3 is formed. Next, as shown in FIG. 1B, after exposure through an exposure mask 4, development and post-baking are performed to form red pixels 5 as shown in FIG. 1C.

  In the same manner, after forming the green pixel 6 and the blue pixel 7 in the gap generated by the development as shown in FIG. 1D, the transparent electrode layer (ITO layer) and the photospacer (both shown in FIG. (Not shown) to form a color filter substrate.

  FIG. 2 shows a phenomenon in which defects occur when foreign matter adheres to the colored resin film in the exposure process. That is, as shown in FIG. 2 (a), when the foreign matter 8 adheres to the surface of the red colored film 3, the distance between the red colored film 3 and the exposure mask 4 is as narrow as 50 to 100 μm in proximity exposure. 8 comes into contact with the exposure mask 4, and scratches (damage) 9 or stains are generated in the exposed portion of the exposure mask 4. Alternatively, the foreign matter 8 may adhere to the exposure mask 4.

  As a result, as shown in FIG. 2 (b), thereafter, using the same exposure mask 4 having scratches 9 or foreign matters, it is formed in a region separated by a black matrix 2 ′ on another glass substrate 1 ′. When the formed red colored film 3 ′ is exposed and developed as shown in FIG. 1C described above, white defects are generated in the red pixel. Such a white defect is generated at the same coordinate on any substrate exposed using the same exposure mask 4.

  FIG. 3 is a diagram showing a CCD line sensor defect inspection apparatus for inspecting a defect of a color filter substrate. In FIG. 3, the color filter substrate 11 is illuminated from the light source 13 while being conveyed on the conveyor 12, and is received by the line sensor 14 to detect a defect. The detected defect signal is processed by an image processing device connected to the line sensor 14, and the obtained inspection results such as the defect position and the number of defective pixels are stored in a computer connected to the image processing device.

  Defects that occur continuously at the same position on a plurality of color filter substrates using the same exposure mask as shown in FIG. 2B are recognized as common defects by the inspection machine shown in FIG. Is done. At this time, “common defect flag”, “in-substrate X coordinate”, “in-substrate Y coordinate”, and “number of defective pixels” are recorded for this defect.

Note that the number of defective pixels in FIG. 4 refers to the defective area (number of pixels) recognized for each image element of the CCD camera shown in (b) with respect to the defective area (μm ² ) shown in (a). It is.

  The operator determines whether or not the defect is good by using a microscope or the like in the inspection apparatus, and if the defect does not affect the product quality, registers the good product coordinates for that part. At this time, “in-substrate X coordinate”, “in-substrate Y coordinate”, and “number of defective pixels” are recorded as registration data. This defective pixel number is referred to as “reference common pixel number”.

  After that, the inspection apparatus sequentially inspects the plurality of color filter substrates, and if a defect is detected with respect to the coordinates registered in the good product coordinates, it is determined as a good product defect, and the substrate processing process is performed as it is without detecting an abnormality. continue. In this way, when a defect is determined to be a good product when a common defect occurs, the conventional countermeasures can effectively eliminate foreign matter adhering to the surface during coloring resin coating or damage to the exposure mask caused thereby. Not in. For this reason, as the production continues, the abnormal state of the defective part spreads, and the defective product level may be exceeded beyond the non-defective product level. However, defects that have been registered as non-defective coordinates cannot be found because they are handled as non-defective products, and will lead to the outflow of defective products. This is the growth type common defect described above.

  In the present embodiment, as shown in FIG. 5, after performing non-defective product coordinate registration for the common defect and recording the “reference common pixel number”, the subsequent substrate is continuously inspected to detect the target common defect. The number of defective pixels is counted for each of N substrates, which is a set number, and the number of defective pixels for N substrates (the first substrate to the Nth substrate) is averaged. The number of defective pixels is calculated. Further, every time one inspection is completed, N substrates (third substrate to N + 2th substrate) are further added to the previous N substrates (second substrate to N + 1th substrate). ), The “comparative common defective pixel number” is calculated sequentially.

  Then, the difference between the “reference common defective pixel count” and the “comparative defective pixel count” is found, and if a difference value greater than the set value is recognized, it is judged as a “growing common defect” and the non-defective product registration is canceled And detect anomalies.

  As described above, when a “growth type common defect” due to the damage of the exposure mask due to the foreign matter adhering to the surface during the coating of the colored resin is detected, the exposure mask is washed to remove the foreign matter and reused. Or replaced with another exposure mask.

  As described above, according to the defect detection method according to the present embodiment, a “growth type common defect” that has been conventionally overlooked as a non-defective defect can be easily detected, so that a high-quality color filter substrate can be manufactured with a high yield. Is possible.

It is sectional drawing which shows the manufacturing process of the color filter by the die coat method which concerns on one Embodiment of this invention. It is sectional drawing explaining generation | occurrence | production of the growth type common defect in the manufacturing process of the color filter by the die coat method. It is a figure which shows the CCD line sensor defect inspection apparatus used for one Embodiment of this invention. It is a figure explaining the number of defective pixels. It is a figure explaining the detection method of the growth type common defect which concerns on one Embodiment of this invention. It is a flowchart which shows the method of detecting a common defect using the defect inspection apparatus using the conventional CCD line sensor.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1,1 '... Glass substrate, 2, 2' ... Black matrix, 3, 3 '... Red coloring film, 4 ... Exposure mask, 5 ... Red pixel, 6 ... Green pixel, 7 ... Blue pixel, 8 ... Foreign material, 9 ... scratches, 11 ... color filter substrate, 12 ... conveyor, 13 ... light source, 14 ... line sensor.

Claims (2)

  The step of supplying the color filter substrate to a defect inspection apparatus and detecting a common defect, the step of determining whether or not the common defect is a non-defective product, and the step of registering the good product coordinate when it is a good product defect, the common product coordinate registered The process of recording the number of defective pixels as a reference common defective pixel number, the set number of color filter substrates are sequentially applied to the defect inspection device, the common defect that is a non-defective product is detected, and the number of defective pixels of the common defect is counted And calculating the number of comparison common defective pixels by averaging them, and the step of canceling the non-defective coordinate registration when the difference between the reference common defective pixel number and the comparison common defective pixel number exceeds a set difference. A defect inspection method for a color filter, comprising:   For the N color filter substrates that are the set number, the number of defective pixels of the first substrate to the Nth substrate is averaged to obtain the number of comparative common defective pixels, and then one color is sequentially added. Each time the inspection of the filter substrate is completed, the number of defective pixels on the second and subsequent N substrates is averaged to obtain the number of comparative common defective pixels, and the difference between the number of reference common defective pixels and the number of comparative common defective pixels is set. 2. The color filter defect inspection method according to claim 1, wherein when the difference is exceeded, the non-defective coordinate registration is canceled at that time.

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