JPH05188008A - Defect inspecting device - Google Patents

Abstract

PURPOSE:To obtain a defect inspecting device which is capable of inspecting defective parts with laser beam rapidly and of discriminating defects and foreign matters. CONSTITUTION:The laser beam emitted from a laser beam source 1 for inspecting defects is converged by a converging lens 2, an ITo pattern 3 on a glass substrate 4 is irradiated therewith, and the reflected beam is guided to a mask 6 by a mirror 5, and the beam passed through the mask 6 is converged by a lens 7, and received by a light-receiving element 8. When the ITO pattern 9 is normal, the diffracted light from the ITO pattern 3 is generated, and the 0-order light component of the diffracted light is shielded by the mask 6 and other components of the diffracted light are detected by the light-receiving element 8. In the case of a defective pattern, the scattered light components from the normal pattern are reduced due to generation of the scattered light from the defects, and the detecting level of the scattered light from the defects is reduced, and its reduction is detected. In the case of foreign matters, an irregular pattern of the scattered light is indicated, and the detecting level of the scattered light from the normal pattern is increased due to addition of the components of the scattered light from the foreign matter, enabling discrimination of the defects and the foreign matters.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a defect inspection device,
In particular, the present invention relates to a defect inspection device for inspecting a defect of an ITO pattern formed on a glass substrate for a liquid crystal panel.

[0002]

2. Description of the Related Art Recently, liquid crystal display panels have been widely used in various electronic devices. Moreover, the amount of information displayed on the liquid crystal display panel is increasing, and a liquid crystal display panel having a high display density is required. In order to increase the display density, it is necessary to make the wiring pattern between the liquid crystal display and the terminal fine and to narrow the gap between the adjacent patterns.

[0003]

However, when the density of the liquid crystal pattern is increased, adjacent patterns may be electrically connected to each other due to insufficient etching in the pattern etching process. For such defects, particularly in a simple matrix pattern, for the defect in which adjacent patterns are connected by a thin pattern, the inspection result from the prober system inspection device provided in the preceding stage (the prober system inspection device is It is used for the inspection for detecting the defect position between the pattern lines based on the inspection between the lines only and it is not possible to specify which position between the lines the defect is.).

The conventional inspection method uses C
A method of detecting a defect by image processing using a CD camera or a method of measuring a resistance between patterns and detecting a defect position is adopted. However, the image processing method using the CCD camera has the disadvantages that it is necessary to detect the defect position while always performing focusing, and that the image processing itself takes time and the inspection time becomes long. In addition, the method of measuring the resistance between patterns has no problem when there is one defect between patterns, but has the drawback that the defect position cannot be detected when there are several defects.

Therefore, a main object of the present invention is to provide a defect inspection apparatus capable of inspecting a defective portion at high speed with a laser beam and further distinguishing a defect from a foreign matter.

[0006]

According to a first aspect of the present invention, there is provided a defect inspection apparatus for inspecting a defect of an object to be inspected, comprising a laser light source for irradiating the object to be inspected with laser light.
Of the reflected light from the inspected object, 0 from the normal pattern
And a mask for blocking the next light component and detecting other scattered light components to detect a defect.

The invention according to claim 2 distinguishes between a defect and a foreign material by utilizing the characteristics of the scattered light pattern of the defect and the foreign material of the object to be inspected and the masking effect of the mask.

The invention according to claim 3 makes it possible to inspect different pattern shapes by rotating the mask.

[0009]

The defect inspection apparatus according to the present invention irradiates the object to be inspected with a laser beam to block the 0th-order light component from the normal pattern among the reflected light from the object to be inspected and other scattered light. Defects are detected by detecting the components.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing the overall construction of an embodiment of the present invention, and FIG.
It is a figure which shows the optical system for defect inspections when a direction differs.

First, referring to FIG. 1, a defect inspection laser light source 1 is provided for emitting a laser beam for defect inspection melting, and the emitted laser beam is condensed by a condenser lens 2.
The ITO pattern 3 formed on the glass substrate 4 is irradiated. The laser light reflected by the ITO pattern 3 is reflected by the mirror 5 and guided to the mask 6. The mask 6 shields the scattered light from the defect of the ITO pattern 3 and the 0th-order light component of the defect inspection laser light. The mask 6 is rotatably attached, and the ITO pattern 3 of the inspection object
Even if the directions (vertical and horizontal) of (1) change by 90 ° as shown in FIG. 2, for example, the scattered light from the defect and the 0th-order light component of the defect inspection laser light can be shielded. The scattered light from the normal pattern and the scattered light from the foreign matter are condensed on the light receiving element 8 via the condenser lens 7. The light receiving element 8 detects the scattered light from the normal pattern and the scattered light from the foreign matter. The glass substrate 4 is movable in the XY directions by the XY table 9.

FIG. 3 is a diagram showing each scattered light pattern and detection level. In particular, FIG. 3 (a) shows a normal ITO pattern, an example of the scattered light pattern and the scattered light detection level, and FIG. 3C shows an example of a defective ITO pattern and its scattered light pattern and a scattered light detection level, and FIG. 3C shows an example of a foreign substance and its scattered light pattern and a scattered light detection level. The scattered light detection levels shown in FIG. 3 are examples of the foreign matter detection threshold and the defect detection threshold.

Next, the operation of one embodiment of the present invention will be described with reference to FIGS. With the arrangement of the optical system shown in FIG. 1, laser light is emitted from the defect inspection laser light source 1, condensed by the condenser lens 2, and irradiated onto the ITO pattern 3. The reflected light from the ITO pattern 3 is guided to the mask 6 by the mirror 5, and the light passing through the mask 6 is detected by the light receiving element 8 via the condenser lens 7. In this case, as shown in FIGS. 3A to 3C, the scattered light pattern differs depending on each case. By combining the difference in the scattered light pattern and the shielding effect of the mask 6, it becomes possible to discriminate the normal pattern, the defective pattern and the foreign matter.

That is, in the case of a normal pattern, diffracted light is generated from the ITO pattern 3 on the surface of the object to be inspected.
The 0th-order light component of this diffracted light is blocked by the mask 6, and the other diffracted light is detected by the light receiving element 8, so that FIG.
It is possible to obtain a detection level signal as shown in FIG.

On the other hand, in the case of a defect pattern, FIG.
The scattering pattern of scattered light is as shown in (b). This is slightly different depending on the shape of the defect, but in the case of the conduction defect of the ITO pattern 3, there is a characteristic that strong scattering is exhibited in the direction within the shielding range of the mask 6. At this time, due to the generation of scattered light from the defect, the scattered light component from the normal pattern decreases, and the detection level decreases at the defect portion, as shown as an example of the scattered light detection level from the defect. By setting the threshold value as shown as an example of the threshold value for defect detection of this decrease in the detection level and comparing it with the detection level,
It becomes possible to inspect for defects.

In the case of a foreign substance, it has an irregular scattered light pattern as shown in FIG. 3 (c) because it has no regular shape and is projected. At this time, the scattered light detection level from the normal pattern increases due to the addition of the scattered light component from the foreign matter due to the generation of scattered light from the foreign matter. Therefore, the phenomenon which is completely opposite to that of the case of the defect is exhibited, and the defect and the foreign matter can be distinguished. When it is desired to detect a foreign substance, the threshold value shown as an example of the foreign substance detection threshold value is set, and the foreign substance can be detected by comparing with the scattered light detection level.

[0017]

As described above, according to the present invention, the object to be inspected is irradiated with laser light, the 0th order light component from the normal pattern of the reflected light is shielded, and other scattered light components are excluded. Since the defect is detected and the defect is detected, the defective portion can be inspected at high speed by laser light. further,
Since it is possible to distinguish between a defect and a foreign substance, it is possible to reduce the influence of the foreign substance, which is a problem in the optical inspection method, particularly in the scattered light inspection method. Further, it becomes easy to count the number of foreign matters.

[Brief description of drawings]

FIG. 1 is a diagram showing the overall configuration of an embodiment of the present invention.

FIG. 2 is a diagram showing a defect inspection optical system in the case where ITO patterns to be inspected are different in 90 ° direction.

FIG. 3 is a diagram showing respective scattered light patterns and detection levels.

[Explanation of symbols]

 1 laser light source for defect inspection 2, 7 condenser lens 3 ITO pattern 4 glass substrate 5 mirror 6 mask 8 light receiving element 9 XY table

Claims (3)

[Claims] 1. A defect inspection apparatus for detecting defects in an object to be inspected, comprising: a laser light source for irradiating the object to be inspected with a laser beam; and a normal pattern of light reflected from the object to be inspected. 2. A defect inspection apparatus comprising a mask for blocking the 0th-order light component from and detecting other scattered light components for defect detection. 2. The defect according to claim 1, wherein the defect and the foreign substance are discriminated by utilizing the characteristics of the scattered light pattern of the defect and the foreign substance of the inspection object and the masking effect of the mask. Inspection equipment. 3. A different pattern shape can be inspected by rotating the mask.
The defect inspection apparatus according to claim 1.