JPH0651011A - Method and device for inspecting liquid crystal substrate of thin film transistor type - Google Patents

Abstract

PURPOSE:To sense different types of shortcircuiting defects on a substrate with high sensitivity contactlessly and quickly by using an infrared image to monitor the change in the heat emitting condition caused by the current flowing between a scanning line and a signal line. CONSTITUTION:Probes 36a, 36b are contacted with wiring pattern on a TNT liquid crystal substrate 30 placed on a (theta) stage 31 for rotation in a horizontal plane, and a voltage from a power supply 35 is impressed between a scanning line and a signal line, and the infrared image in the voltage impressed state is sensed by an infrared image sensor 5 when a certain time has passed since the voltage was impressed, while infrared image in the condition with voltage impression stopped is sensed by the same sensor 5 when a certain period has elapsed since the voltage impression was stopped. A differential image sensing circuit 55 senses the differential infrared image from a plurality of overlapped infrared images in the conditions with and without voltage impression, and the results is subjected to image processing by a coordinates sensing circuit 56, and the max. value corresponding position in the differential infrared image is sensed. A shortcircuit position determining circuit 69 determines as real shortcircuit position the shortcircuit position candidate which lies nearest the pattern inconsistency coordinates determined by a pattern matching circuit 67.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inspection method and apparatus for detecting defects in a pattern to be inspected, and more particularly to a method of inspecting a thin film transistor liquid crystal substrate used in a liquid crystal display device as a pattern to be inspected. It relates to the device.

[0002]

2. Description of the Related Art FIG. 1 shows a 5 × 5 pixel array as an example of an electrical wiring structure of a thin film transistor active matrix substrate (hereinafter, simply referred to as a thin film transistor liquid crystal substrate). As can be seen from this, the thin film transistor liquid crystal substrate is one in which the scanning lines 11 to 15, the signal lines 21 to 25, and the thin film transistors 7 and the transparent pixel electrodes 8 are formed on the glass substrate at the intersections of the signal lines and the scanning lines. However, a liquid crystal display device is basically constructed by enclosing liquid crystal between the thin film transistor liquid crystal substrate and the common electrode substrate in parallel with each other. In the drawing, reference numerals 11p to 15p denote electrode terminal pads corresponding to the scanning lines 11 to 15, and 21p to 21p.
Reference symbols p to 25p denote electrode terminal pads corresponding to the signal lines 21 to 25.

In the thin film transistor liquid crystal substrate having the above structure, if a short-circuit defect 3 occurs between the scanning line 13 and the signal line 23, a display defect along the scanning line 13 and the signal line 23 will occur. It occurs linearly. By the way, as shown in FIG. 2A, the short-circuit defect 3 includes a short-circuit defect 3a generated at the intersection of the scanning line and the signal line and a short-circuit defect 3b generated in the thin film transistor 7.
However, as a countermeasure against these short-circuit defects 3a and 3b, as shown in FIG. 2B, a method of forming a plurality of signal line / scan line intersections and thin film transistors 7 has been considered. In this case, the short circuit defects 3a and 3d can be corrected by cutting the wiring at the wiring cutting positions 9a and 9d. However, when this method is actually applied, it is necessary to specify the occurrence position of the short-circuit defect in advance.

Here, a conventional inspection method for confirming the presence / absence of a short-circuit defect is shown in FIG. According to this inspection method,
One end of each of the scanning lines 11 to 15 is commonly connected by the connection wiring 1c via the scanning line electrode terminal pads 11p to 15p and the external wirings 11d to 15d, while the signal lines 21 to 25 are connected.
One end of each of them has a signal line electrode terminal pad 21p.
˜25p, connection wiring 2c through external wirings 21d to 25d
Are commonly connected by. In such a connection state, the probe is brought into contact with the connection wirings 1c and 2c, and the voltage V is applied between the scanning lines 11 to 15 and the signal lines 21 to 25,
If the ammeter 4 measures the current value, the presence or absence of a short circuit defect can be determined. However, according to this method, even if it can be confirmed that some kind of short-circuit defect has occurred, it is impossible to identify the pixel address where the short-circuit defect occurs. In order to specify the pixel address, targeting the thin film transistor liquid crystal substrate having the wiring structure shown in FIG. 1, the current value in the state where the voltage V is applied only to any one scanning line and any one signal line It suffices to perform the measurement sequentially for the combination of the scanning line and the signal line.
However, in this method, since it is necessary to measure the current value by the number of times of the product of the number of scanning lines and the number of signal lines, not only the current measurement work is complicated to identify the pixel address where the short circuit defect occurs. , It will take a lot of time. In addition to such a problem, damage to the electrode terminal portion due to contact of the probe becomes a problem. In order to shorten the inspection time, it is possible to contact a large number of probes at the same time. Even if the pixel address where the short-circuit defect occurs can be specified by this, even if the pixel address of FIG.
As shown in (b), in the thin film transistor liquid crystal substrate in which the scanning line / signal line intersections and the thin film transistors are formed, it is possible to determine which scanning line / signal line intersection or the thin film transistor has a short circuit defect. Is unidentifiable.

On the other hand, apart from the above, as a method of shortening the inspection time, an electrochromic display panel is used,
A method for detecting a defect from the color-developed state of the color-developing film is described in JP-A-1-154092. According to this method, since the color forming film is in a non-coloring state or a coloring state depending on the conduction state of each pixel electrode, it is possible to specify the defective pixel. However, in the case of this method, since it is necessary to conductively connect the pixel electrode of the thin film transistor liquid crystal substrate and the color forming film of the electrochromic display substrate through the electrolyte, the problem of contamination when using a liquid electrolyte, Further, when a solid electrolyte is used, problems such as damage remain.

[0006]

As described above, in the prior art, short-circuit defects on the thin film transistor liquid crystal substrate cannot be detected with high sensitivity and damage to the substrate itself. Is the reality. Even if the pixel address where the short-circuit defect exists can be specified, if there is a plurality of scanning line / signal line intersections or thin film transistors themselves for each pixel, any intersection, or thin film transistor It was impossible to identify whether or not there is a short circuit defect.

It is an object of the present invention to provide a thin film transistor liquid crystal substrate inspection method and apparatus capable of quickly detecting various short-circuit defects existing on the thin film transistor liquid crystal substrate with high sensitivity and without contacting the substrate. It is in.

Another object of the present invention is to determine which intersection or thin film transistor has a short-circuit defect, even in a thin film transistor liquid crystal substrate having a plurality of scanning line / signal line intersections or thin film transistors themselves. The present invention provides an identifiable thin film transistor liquid crystal substrate inspection method and apparatus.

Another object of the present invention is to make various short circuit defects existing between scanning lines / signal lines, between scanning lines, or between signal lines on a thin film transistor liquid crystal substrate non-contact with the substrate, An object is to provide a method of inspecting a thin film transistor liquid crystal substrate that can be rapidly detected.

Another object of the present invention is to increase the S / N size of the short-circuit defect position existing between scanning lines / signal lines, between scanning lines or between signal lines on the thin film transistor liquid crystal substrate, and An object of the present invention is to provide a method for inspecting a thin film transistor liquid crystal substrate that can be quickly detected without contacting the substrate.

Another object of the present invention is to provide a method for inspecting a thin film transistor liquid crystal substrate which can detect the position of a short circuit defect existing in a pixel region on the thin film transistor liquid crystal substrate in a non-contact manner with the substrate and can be quickly detected. It is in.

Another object of the present invention is to specify a pixel address having a short circuit defect even in a thin film transistor liquid crystal substrate having a plurality of scanning line / signal line intersections or thin film transistors themselves. An object of the present invention is to provide a method for inspecting a thin film transistor liquid crystal substrate that can detect the short circuit defect position in the pixel address without contacting the substrate.

Another object of the present invention is to provide an inspection apparatus for a thin film transistor liquid crystal substrate having a structure in which the above various inspection methods for a thin film transistor liquid crystal substrate can be easily carried out.

[0014]

The present invention adopts the following characteristic items in order to achieve the above object.

A voltage is applied between the scanning line and the signal line of the thin film transistor liquid crystal substrate, and a change in the heat generation state due to the current flowing through the short-circuit defective portion of the scanning line and the signal line is detected by the infrared image detector.

The scanning line and the signal line of the thin film transistor liquid crystal substrate are electrically connected commonly at one terminal.

With respect to the scanning lines existing between the terminals electrically connecting the scanning lines and the pixel region, and the signal lines existing between the terminals electrically connecting the signal lines and the pixel region,
The pixel address in which the short-circuit defect has occurred is specified by obtaining the change in the heat generation state before and after applying the voltage from the infrared image.

With respect to the pixel portion in which the short-circuit defect has occurred, the position in which the short-circuit defect has occurred is specified by obtaining the change in the heat generation state before and after applying the voltage from the infrared image.

Detection of a change in heat generation state before and after applying a voltage by using a difference in infrared image or a quotient.

For the pixel address where the short-circuit defect has occurred, the position where the short-circuit defect has occurred is specified by referring to the visible image of the wiring pattern of the thin film transistor liquid crystal substrate.

The sensitivity of the detector is detected by the infrared image detector which is lowered toward the periphery of the light receiving portion.

Since there is a resistance of several tens of megohms between the scanning line and the signal line of a normal thin film transistor liquid crystal substrate, even if a voltage of several tens of volts is applied between the scanning line and the signal line, almost no current flows. Not flowing. On the other hand, when there is a short-circuit defect between the scanning line and the signal line in the thin film transistor liquid crystal substrate, a current flows through this short-circuit defect part, and a short-circuit part having a resistance value larger than the resistance of the normal wiring part and Phenomena in which heat is generated around the area are generated. When the heat generation state is detected by an infrared image detector, an image having a value proportional to the product of the emissivity γ and the temperature T to the fourth power is obtained. By the way, the value of the emissivity γ is close to 1 for glass and close to 0 for wiring patterns such as chromium and aluminum, so that the observed image is affected by the difference in emissivity. Therefore, in order to detect minute heat generation with high sensitivity, it is necessary to eliminate the influence of emissivity. Therefore,
By detecting the image before and after applying voltage and detecting the difference (quotient), it is possible to detect subtle state changes due to minute heat generation at the short-circuit defect part, and to accurately identify the short-circuit position. Is.

For the pixel address where the short circuit defect actually occurs, refer to the visible image of the wiring pattern.
The position where the short circuit defect has occurred can be easily specified.

Further, the temperature distribution of the heat generating portion gradually decreases as the distance from the center of heat generation increases. For this reason,
When the sensitivity of the detector is detected by the infrared image detector which is lowered toward the periphery of the light receiving part, the peak position of the heat generation center can be accurately obtained.

Further, the present invention is an inspection method or inspection apparatus for applying a voltage, heat, an electric field or the like from the outside and detecting the state change thereof, which has means for determining the position of the image, and the detected image before the application. The inspection method or the inspection apparatus focuses on accurately calculating the position of a point or an area where the state changes by obtaining the positional relationship between the reference image and the reference image. Further, the present invention is characterized in that the reference image is an image before applying a voltage or the like, or a part thereof.

That is, in order to achieve the above object, the present invention applies a voltage between the scanning line and the signal line of the thin film transistor substrate, and changes the heat generation state due to the current flowing through the short-circuit defective portion of the scanning line and the signal line. Detect with infrared image detector.

The scanning line and the signal line of the thin film transistor liquid crystal substrate are electrically connected at one terminal.

The position where the short-circuit defect has occurred is specified by obtaining the change in the heat generation state before and after the voltage application is detected from the infrared image.

The heat generation position is accurately calculated by obtaining the positional relationship between the infrared image and the reference image before voltage application.

The positional relationship between the images is performed by, for example, matching the images.

Since there is a resistance of several tens of megohms between the scanning line and the signal line of a normal thin film transistor substrate, even if a voltage of several tens of volts is applied between the scanning line and the signal line, almost no current flows. Absent. On the other hand, if there is a short circuit defect between the scanning line and the signal line in the thin film transistor substrate,
A current flows through this short-circuit defect portion, and the short-circuit portion having a resistance value larger than that of the normal wiring portion and the periphery thereof generate heat. When this is detected by the infrared image detector, a value obtained by adding the product of the function R (T) of the object temperature T and the emissivity ε and the product of the function R (Ta) of the ambient temperature and (1-ε) An image with is obtained. Since the value of the emissivity ε is close to 1 for glass and close to 0 for wiring patterns such as chromium and aluminum, the observed image is affected by the external environment. Therefore, in order to detect minute heat generation with high sensitivity, it is necessary to remove the influence of the external environment. Therefore, by detecting the image before and after applying the voltage and detecting the difference, the influence of the external environment can be removed, and a subtle state change due to the minute heat generation of the short circuit portion can be detected.

However, in many cases, the infrared image detector is usually of a point type and has a structure in which a two-dimensional image is detected by scanning a mirror. With this configuration,
Reproducibility cannot be guaranteed because the scanning position drifts over time. Further, even in the case of a two-dimensional type, if the lens is distorted, the short circuit position cannot be accurately obtained. Therefore, the correct short circuit position can be measured by aligning the infrared image before voltage application with the reference infrared image.

Further, according to the present invention, the voltage is applied between the scanning lines and the signal lines, between the scanning lines, or between the signal lines in the thin film transistor liquid crystal substrate. The change in the heat generation state due to the current flowing between the signal lines is detected from the difference or quotient between the infrared image when the voltage is applied and the infrared image when the voltage is not applied. Is to detect a short-circuit defect that exists between scan lines, scan lines, or signal lines.
More preferably, the infrared image is detected after a predetermined time elapses from the time when the voltage is applied between the scanning lines and the signal lines, between the scanning lines or between the signal lines, while the predetermined time elapses from the time when the voltage application is stopped. After that, the infrared image is detected, and the change in the heat generation state due to the current flowing between the scanning lines and the signal lines, between the scanning lines, or between the signal lines is detected. The short-circuit defect is detected by detecting the difference from the infrared image or the quotient (ratio).

Further, according to the present invention, the infrared image is detected after a predetermined time has elapsed from the time when a voltage was applied between the scanning lines and the signal lines, between the scanning lines or between the signal lines in the thin film transistor liquid crystal substrate, while applying the voltage. Detection of an infrared image is repeated a plurality of times after a lapse of a predetermined time from the time of stopping, and a change in heat generation state due to a current flowing between the scanning lines and the signal lines, between the scanning lines, or between the signal lines. Between the scanning line and the signal line by detecting from the difference or quotient between the plurality of superimposed infrared images in the voltage applied state and the plurality of superimposed infrared images in the voltage applied state, Detecting a short-circuit defect existing between scanning lines or between signal lines.

Further, according to the present invention, the plurality of scanning lines and the signal lines on the thin film transistor liquid crystal substrate are electrically connected in common on one terminal side, and the voltage is applied between the scanning lines and the signal lines. While the infrared image outside the pixel area is detected after a predetermined time has elapsed, the infrared image outside the pixel area is detected after a predetermined time has elapsed from the time when the voltage application was stopped, and the scanning line related to the change in the heat generation state And the signal line is detected from the difference between the infrared image when the voltage is applied and the infrared image when the voltage is not applied, or the quotient to detect the coordinates where the short-circuit defect occurs. It is to be.

Further, according to the present invention, after the pixel address in which the short-circuit defect has occurred is detected in a specified state, a differential infrared image at the pixel address is applied with a voltage between the scanning line and the signal line. The difference between the infrared image detected after the lapse of a predetermined time from the time point and the infrared image detected after the lapse of the predetermined time from the time when the voltage application is stopped, or the quotient, and the set threshold value Detect the short circuit defect position by comparing,
Alternatively, the wiring pattern position at the pixel address is detected from the visible image of the pixel address, while the short circuit defect position is detected by comparing the wiring pattern at the pixel address with the wiring pattern at the adjacent pixel address. is there.

Further, according to the present invention, in order to optically detect an image at an arbitrary position on the thin film transistor liquid crystal substrate, the thin film transistor liquid crystal substrate is positioned in the X, Y and Z directions and at the X position.
A voltage is applied between the scanning line and the signal line, between the scanning lines, or between the signal lines in the thin film transistor liquid crystal substrate mounted on the stage system and the stage system on which the rotational position θ in the Y horizontal plane is set arbitrarily. A voltage application system that can be applied, and an illumination system that illuminates the thin film transistor liquid crystal substrate with visible light to detect a wiring pattern at a desired position on the thin film transistor liquid crystal substrate mounted on the stage system as a visible image, An infrared image at an arbitrary position on the thin film transistor liquid crystal substrate placed on the stage system is detected after a predetermined time has elapsed from the voltage application start time and the voltage application stop time, and the image processing is performed in a predetermined manner, thereby causing a short circuit. An infrared image detection processing system for identifying the presence / absence of a defect, specifying a short-circuit defect occurrence pixel address and specifying a short-circuit defect position in the short-circuit defect occurrence pixel address; A thin film transistor mounted on the system detects the wiring pattern at an arbitrary position on the liquid crystal substrate as a visible image and then performs image processing in a predetermined manner to identify the position of the short-circuit defect in the pixel address where the short-circuit defect occurs. And an image detection processing system.

Detect a short-circuit defect from the difference image between the infrared image between the scanning lines and the signal lines, between the scanning lines or between the signal lines and the infrared image when the voltage application is stopped. However, at that time, by detecting the infrared image within a short time after the voltage application is stopped, the change in brightness near the short-circuited portion caused by the diffusion of heat is canceled and the influence of the heat diffusion is eliminated. After compensation, presence / absence of a short-circuit defect and its position identification are performed with high accuracy. Specifically, the infrared image is detected after a lapse of a predetermined time from the time when the voltage is applied between the scanning lines and the signal lines, between the scanning lines, or between the signal lines, while the infrared image is detected for the predetermined time from the time when the voltage application is stopped. An infrared image is detected after a lapse of time, and the change in the heat generation state due to the current flowing between the scanning lines / signal lines, between the scanning lines, or between the signal lines is detected, and the infrared image in the voltage applied state and the voltage application stopped The short-circuit defect is detected by detecting the difference from the infrared image in the state or the quotient.

The infrared image detection timing at that time is specifically determined by the current value or the heat generation amount detected in advance,
Individually determined, and in order to improve the S / N on the differential infrared image, the infrared image in each of the voltage application state and the voltage application stop state is detected multiple times, and then the voltage application state is detected. The difference between the superimposition image of the multiple infrared images at and the superimposition image of the multiple infrared images when the voltage application is stopped detects the short-circuit defect from the infrared image and is detected in a more visible state. I will get it. The presence or absence of a short-circuit defect can be generally detected by comparing the difference infrared image thus obtained with a set threshold value.

Whether or not any short circuit defect exists in the thin film transistor liquid crystal substrate can be detected with high accuracy as described above, but from the viewpoint of improving the yield of the thin film transistor liquid crystal substrate, the short circuit defect is particularly noticeable. Is required to be detected in a state where its position is specified and to be subsequently removed by laser light. The pixel address where the short circuit defect occurs is the difference between the pixel area outside infrared image in the state where voltage is applied between the scanning line and the signal line and the pixel area outside infrared image in the state where voltage application is stopped, or Although it can be detected from the quotient, the difference infrared image within the pixel address (when the heat generation amount at the short-circuit defect position is large) or the visible image at the pixel address and the adjacent pixel address (short-circuit defect position) It is possible to easily detect at what position in the pixel address the defect has occurred from the case where the amount of heat generated in (1) is relatively small.

[0041]

According to the present invention having the above structure, the scanning lines / signal lines on the thin film transistor liquid crystal substrate, the adjacent scanning lines,
Alternatively, various short-circuit defects existing between adjacent signal lines can be quickly detected by making them non-contact with the substrate. Further, in the present invention, scanning lines on the thin film transistor liquid crystal substrate
The position of the short circuit defect existing between the signal lines, between the adjacent scanning lines, or between the adjacent signal lines can be made S / N large, and can be brought into non-contact with the substrate, and can be detected promptly. In the present invention, the short-circuit defect position existing in the pixel region on the thin film transistor liquid crystal substrate is brought into non-contact with the substrate,
Moreover, it can be promptly detected as a pixel address. Further, in the present invention, even in the thin film transistor liquid crystal substrate in which the scanning line / signal line crossing portion or the thin film transistor itself is pluralized, after specifying the pixel address in which the short circuit defect exists, within the pixel address The position of the short-circuit defect can be detected quickly without contacting the substrate. Further, according to the present invention, there can be obtained a thin film transistor liquid crystal substrate inspection apparatus in which the various thin film transistor liquid crystal substrate inspection methods described above can be easily carried out.

[0042]

First, the theoretical background of the present invention will be described.

That is, since a resistance of about several tens of megohms is usually present between the scanning line and the signal line on a normal thin film transistor substrate, a voltage of about several tens of volts is applied between the scanning line and the signal line. Even if is applied, almost no current flows. On the other hand, when a short circuit defect exists between the scanning line and the signal line, a current flows through each of the scanning line and the signal line through the short circuit defect portion, but at that time, the resistance value at the short circuit defect portion is Generally, since the resistance value is higher than that of a normal wiring portion, the short-circuit defect portion and its vicinity are in a heat generation state.

Incidentally, when detecting an infrared image, the infrared image is apparently as shown in the document "Principle and Method of Thermography Device" Thermoviewer "" (Product Information of JEOL Ltd.). The emissivity of the object (emissivity: defined as the ratio of the radiant energy of an object other than a black body to the radiant energy of a black body at the same temperature) ε and the product of the function R (T) of its true temperature T; Reflectance 1
−ε and the temperature of the reflection source (surrounding object) (usually room temperature) T ′
With the product of the function R (T '), that is, ε × R (T) +
It is obtained as an image having an apparent temperature of (1-ε) × R (T ′) as brightness. However, the functions R (T) and R (T ′) represent the effective incident intensities corresponding to the temperatures T and T ′, respectively.

Since the value of the emissivity ε is close to 1 for glass and close to 0 for the wiring pattern of chromium or aluminum, the observed image is affected by the difference in emissivity ε. When the temperature of the target and the reflection source are both the same, the image value depends only on the function R (T) and is independent of the value of the emissivity ε. It is affected by the difference in the rate ε. The reflection source also includes an objective lens in an infrared detector. Here, if the temperatures of the target and the reflection source are equalized, the value of the image depends only on the function R (T), so that the temperature of the target can be correctly measured. Therefore, in order to measure the temperature rise at the short-circuit defect portion, it is sufficient to detect the difference infrared image from the infrared images before and after the voltage application. However, if attention is paid to the vicinity of the short-circuit defect portion, there is a temperature rise due to heat diffusion. That is, in the vicinity of the short-circuit defect portion, the temperatures of the target and the reflection source are not equal, and the image value does not depend only on the function R (T). As a result, in the difference infrared image detected from the infrared images before and after the voltage application, the difference in emissivity depending on the target location appears and the pattern looks like a pattern. It becomes difficult to identify the defective portion.

As described above, in order to detect the heat generation position due to the short-circuit defect with high sensitivity, it is necessary to eliminate the influence due to the difference in emissivity, but according to the present invention, the difference in emissivity depending on the target location. It is possible to eliminate the effect of. In particular, if the infrared image is detected within a short time after the application of the voltage is stopped, the change in brightness near the short-circuit defect portion due to the diffusion of heat can be offset. The detection of such an image is more effective than the case of detecting the infrared image within a short time after the voltage is applied. That is, in the latter case, the heat transfer rate is increased and the heat is transmitted through the glass substrate, so that the temperature in the vicinity of the short-circuit defect portion immediately rises, whereas in the former case, the temperature is increased in the vicinity of the short-circuit defect portion. The diffused heat has a low heat transfer coefficient and is transferred through the air and does not cool immediately. Therefore, if the infrared image is detected within a short time after the voltage application is stopped, the temperature in the vicinity of the short-circuit defect portion does not change significantly, so that not only the short-circuit defect portion can be detected but its position can be accurately identified. It is a thing.

First, an embodiment of the present invention will be described with reference to FIGS.

First, referring to FIG. 4, the short-circuited pixel address specifying method will be described in detail. In FIG. 4, in the thin film transistor liquid crystal substrate, the scanning lines 11 to 15 have electrode terminal pads 11p.
External wirings 11d to 15d formed outside ˜15p and electrically connected in common by the connection wiring 1c, and the signal lines 21 to 25 are external wirings 21d to 25p formed outside the electrode terminal pads 21p to 25p. 25d and the connection wiring 2c are electrically connected in common. In such a connected state, the scanning lines 11 to 15 and the signal lines 21 to 2
In order to apply the voltage V between the scanning line 13 and the signal line 2, if a probe for voltage application is brought into contact with the connection wirings 1c and 2c, as shown in FIG.
When the current is generated in the pixel where 3 intersects, the current flows to the external wiring 13d → the electrode terminal pad 13p → the short circuit defect 3 → the electrode terminal pad 23p → the external wiring 23d, and the wiring between these paths has the current. Will generate heat. At that time, if the resistance value at the short-circuit defect 3 is larger than that at the scanning line 13 and the signal line 23, the amount of heat generated between the paths is large even if the current is small. 3 can be detected. That is, for example, the external wirings 11d to 15d and the external wirings 21d to
25d is detected by an infrared microscope along the broken line 6 before and after the voltage is applied, and the difference between the detected image signals is calculated to calculate the projection in the X and Y directions. The difference signal waveform shown in FIG. By detecting a position having a value, it is possible to detect the wiring position in a heating state, that is, the scanning line 13 and the signal line 23. As a result, it is possible to identify the short-circuited pixel address of various short-circuit defects. At that time, instead of calculating the difference between the image signals detected by the infrared microscope, the quotient is calculated by division. Also, the short-circuited pixel address can be specified. In this example, when there are N short circuits in the substrate, the maximum number of scanning lines and signal lines detected is N.

Now, the structure of the thin film transistor liquid crystal substrate inspecting apparatus according to the present invention will be described. FIG. 5 shows an example of the structure. In this case, the inspection apparatus is roughly composed of a mechanical system 100, a voltage application system 101, and an optical system. Of these, the mechanical system is a θ stage (horizontal plane rotation stage) 31, Z
It is composed of a stage 32, an X stage 33, and a Y stage 34. By mounting the thin film transistor liquid crystal substrate 30 on the θ stage 31, the thin film transistor liquid crystal substrate 30 can be positioned at an arbitrary position within the visual field of the optical system. There is. The position of the X stage 33 is detected by the position detector 53, but the same applies to the other Y stages 34 and the like. The voltage application system 101 includes a power source 35, an ammeter 4 and probes 36a and 36b.
By bringing a and 36b into contact with the wiring pattern, a potential difference is applied between the scanning lines and the signal lines, between the signal lines, or between the scanning lines. On the other hand, the optical system includes an infrared image detection processing system 102 and a laser beam irradiation system 10 for cutting wiring.
3, a bright field illumination system 104, a transmitted illumination system 105, and a visible image detection processing system 106. Among them, the infrared image detection system includes an objective lens 37, a dichroic mirror 38, a lens 39 and an infrared image detector 5, and infrared light (wavelength range λ ₁ : About 3 to 13 μm, especially about 3 to 5 μm, or about 8 to 13 μm) is detected as an infrared image. In this infrared image detection system, the objective lens 3
Since the infrared image is magnified in 7, it is possible to detect the infrared light emitted from a minute region of about 1 to 20 μm, that is, the intensity of the infrared light in a good condition. The laser light irradiation system 103 includes a laser oscillator 43, a beam expander 42, an opening 41 (having a moving mechanism (not shown)) and a dichroic mirror 40, and the laser light transmitted through the opening 41 is passed through the objective lens 37. By reducing the size and projecting it onto the thin film transistor liquid crystal substrate 30, the wiring pattern at a desired position, specifically, the wiring pattern forming the short-circuit defect can be cut. It should be noted that the correction of the short-circuit defect is not limited to the laser beam, and it is clear that an energy beam such as an ion beam or an electron beam may be used. Bright field illumination system 1
Reference numeral 04 also includes a lamp 46, a lens 45, and a half mirror 44, and illuminates the thin film transistor liquid crystal substrate 30 with visible light from above via the objective lens 37. Further, the transmitted illumination system 105
Is composed of a lamp 50 and a lens 49, and the thin film transistor liquid crystal substrate 30 is illuminated with visible light from the back side thereof. Furthermore, the visible image detection system 1
06 includes a visible image detector 48 and a lens 47. The visible image detector 48 is adjusted in advance so as to detect the visible image at the same position on the infrared image detector 5 and the thin film transistor liquid crystal substrate 30. Further, in this embodiment, the objective lens 37 needs to transmit light in the visible range to the infrared range, and ZnS or the like may be used for the glass material. Further, the dichroic mirror 38 is an optical element having a characteristic of reflecting light in the detection wavelength range λ ₁ of the infrared image detector 5 and transmitting light having a wavelength shorter than the detection wavelength range λ ₁ . Furthermore, the dichroic mirror 40 has a characteristic of reflecting the wavelength λ ₂ (λ ₂ <λ ₁ ) of the laser light from the laser oscillator 43 and transmitting visible light (wavelength range λ ₃ : λ ₃ <λ ₂ ). In this embodiment, the voltage application, the short-circuited pixel address identification, the short-circuited location identification, and the wiring correction described above are realized by one inspection device.

The thin film transistor liquid crystal substrate inspection device according to the present invention is constructed as described above.
The operation will be described. The thin film transistor liquid crystal substrate 30 disposed on the θ stage 31 has a probe 36.
Since a and 36b are brought into contact with the wiring pattern,
A potential difference is applied between the scanning line and the signal line, and the image before and after the application of the potential difference are detected as infrared images by the infrared image detector 5 through the objective lens 37.

More specifically, the infrared image in the voltage applied state is first detected after a lapse of a predetermined time T ₁ from the start of voltage application, while the voltage application is stopped after a predetermined time T ₂ from the stop of the voltage application. The infrared image in the state is detected. As shown in FIG. 10, the predetermined times T ₁ and T ₂ are generally different from each other, and are appropriately set based on the current value detected in advance or the heat generation amount. For example, when the detected current value is large, both the heat generation amount and the heat diffusion amount are large, and in such a case, a relatively short time is set.
The current value also increases when multiple short-circuit defects occur, but when the current value is large, the infrared image is detected once and the amount of heat generated at each short-circuit defect is evaluated. In the above, the predetermined times T ₁ and T ₂ may be set appropriately. Incidentally, in FIG. 10, predetermined times T ₁ , T ₂
Are set to 165 ms and 0 to 300 ms, respectively.

Although the infrared image detected by the infrared image detector 5 generally has a small S / N, in order to improve the S / N, in order to improve the S / N, the voltage application and the voltage application stop are synchronized with each other.
Repeating the detection of the infrared image in each of the voltage application state and the voltage application stop state, the multiple overlay infrared images in the voltage application state and the multiple overlay infrared images in the voltage application state are repeated. The difference infrared image may be obtained by the difference image detection circuit 55 and then image processed by the coordinate detection circuit 56. 11,
FIG. 12 shows an example of the detected difference infrared image when the voltage application / stop is tuned and an example of the detected difference infrared image when the voltage is not tuned. It can be seen that detecting infrared images in time can offset the effects of thermal diffusion.

Returning to FIG. 5 again and continuing the description, the coordinate detection circuit 56 performs image processing on the difference infrared image from the difference image detection circuit 55, so that the position corresponding to the maximum value in the difference infrared image. Is detected. The position is detected as, for example, the position of the center of gravity in the area surrounded by the isotherm lowered by 0.2 ° C, or the difference infrared image is projected in the X and Y directions within the setting area, and is equal to or more than the set value. The barycentric position may be detected from the Y and X coordinates of each area having the value of. However, Y and X in each of the areas having a value greater than or equal to the set value
When the position of the center of gravity is obtained from the coordinates, the position of occurrence is simultaneously obtained as the position of the center of gravity corresponding to a plurality of short-circuit defects. When a short circuit defect occurs in the pixel area, first, the short circuit defective pixel address is specified, then the short circuit defect position in the pixel address is specified, and the short circuit defect position is short-circuited. Defect removal processing is performed.

By the way, when the amount of heat generated at the short-circuit defect portion is sufficiently large, the short-circuit defect position can be easily specified, but when not, the position can be specified from the visible image. There is.

Further, as shown in FIG. 9, the reference infrared image 5
7 and the infrared image before voltage application are matched and calculated as Y and X coordinates from a specific position such as the intersection of the scanning line and the signal line. Here, 58 is a difference image, and 59 is an infrared image before voltage application. Matching can be realized as follows, for example.

When the image before voltage application is f (x, y) and the reference image is g (x, y), the value P (Δx, Δ) of the following equation
The values of Δx and Δy that minimize y) are obtained.

P (Δx, Δy) = ΣΣ (f (x-Δx, y-Δy) -g (x, y)) * (f (x-Δx, y-Δy) -g (x, y)) Here, Δx and Δy take values such as −2, −1, 0, 1, 2. If the reference image g (x, y) is selected so as to represent, for example, a region including the intersection of the signal line and the scanning line, where the intersection is located in the image before the voltage is applied by the obtained Δx and Δy. I understand. This enables accurate measurement even if the image has distortion. Reference image g (x, y)
May be a transistor to be disconnected. Although there is an influence of the external environment on the image, a grayscale corresponding to the pattern is generated due to the difference in the emissivity of the pattern, and thus accurate matching can be realized. Further, when the reference image g (x, y) is selected to be relatively small, it is less likely to be affected by the difference in distortion amount in the image.

On the other hand, the image detected by the visible image detector 48 during transillumination is binarized by the binarizing circuit 61, and then the pattern matching circuit 62 converts it to the dictionary pattern from the dictionary pattern setting circuit 63. The pattern matching is performed in step S3, and the dictionary pattern position in the detected image is obtained. The short circuit candidate position detection circuit 64 calculates the short circuit candidate position and the wiring cut position based on the dictionary pattern position data and the coordinate data of the short circuit candidate position and the wire cut position preset in the position coordinate data setting circuit 65. It On the other hand, when the bright field illumination is applied, the visible image detector 4
The image detected in 8 is once stored in the memory 66,
The pattern matching circuit 67 performs pattern matching between the image in the short-circuit defective pixel address and the image in the adjacent pixel address to detect the pattern mismatch coordinates in the short-circuit defective pixel address. Short circuit position determination circuit 6
In 9, the short-circuit candidate position closest to the pattern non-coincident coordinates calculated by the pattern matching circuit 67 is determined as the true short-circuit position. By irradiating the laser beam from the laser oscillator 43 through the beam expander 42 with the opening 41 positioned on the basis of this, the wiring at the desired position is automatically cut and the short-circuit defect can be corrected.

The outline of the operation of the thin film transistor liquid crystal substrate inspection apparatus according to the present invention has been described above. The above operation will be described more specifically and in detail.

First, referring to FIG. 4, the method of identifying the short circuit defective pixel address will be described. As shown in the figure, the scanning lines 11 to 15 on the thin film transistor liquid crystal substrate are led out to the external wirings 11d to 15d through the electrode terminal pads 11p to 15p. In addition, the signal lines 21 to 25 are similarly electrically connected in common by the connection wiring 1c, and similarly, the signal lines 21 to 25 are also similarly connected.
The wirings are led out to the external wirings 21d to 25d through 1p to 25p and are electrically connected in common by the connection wiring 2c. In such a connected state, the scanning line 11
15 to 15 and the signal lines 21 to 25, if voltage application probes are brought into contact with the respective connection wirings 1c and 2c in order to apply the voltage V, as shown in FIG. When 3 is generated at the pixel address where the scanning line 13 and the signal line 23 intersect, the current is external wiring 13d → electrode terminal pad 13p → short circuit defect 3 → electrode terminal pad 23p →
The current flows to the external wiring 23d, and the wiring between these paths generates heat due to the current. At that time, if the resistance value at the short-circuit defect 3 is larger than that at the scanning line 13 and the signal line 23, the amount of heat generated between the paths is large even if the current is small. 3 can be detected. That is, for example, after the infrared images of the external wirings 11d to 15d and the external wirings 21d to 25d are detected by the infrared image detector 5 along the broken line 6 before and after the application of voltage, the detected infrared images have a red color difference. If the projection distribution in the X and Y directions is calculated after obtaining the outside image, the scanning line 13 and the signal line 23 in the heating state are detected by detecting the wiring position having a large value from the projection distribution. Can be detected. In this way, various short-circuit defective pixel addresses of short-circuit defects can be specified. At that time, instead of calculating the difference infrared image from the infrared image detected by the infrared image detector 5, Even if the quotient is calculated by division, the short-circuited pixel address can be easily specified. In this example, if there are N short circuits in the board, the maximum number of scanning lines and signal lines detected is N.
It will be a book.

The above is the method of identifying a short-circuit defect in the pixel area on the pixel address, but the position of a short-circuit defect between signal lines or between scanning lines can be easily specified. When detecting a short-circuit defect between signal lines or between scanning lines, a voltage is applied between an adjacent signal line or an adjacent scanning line, but since the situation is the same in both cases, an explanation will be given. For the sake of simplification, a method of detecting a short-circuit defect between scanning lines and a method of specifying the position thereof will be described below.

That is, in detecting a short circuit defect between scanning lines, the scanning lines at odd-numbered positions are commonly connected,
Similarly, the even-numbered scanning lines are also commonly connected, and a voltage is applied between the odd-numbered scanning lines and the even-numbered scanning lines. If the difference infrared image detected from the pixel area outside infrared image in the voltage applied state and the pixel area outside infrared image in the voltage applied state is projected in the X direction, the short-circuit defective pixel address can be identified. In the same manner as the method, it is possible to detect from the projected distribution shape as a pair in a state where two scanning lines in a heat generating state are adjacent to each other. From this, it is known that a short-circuit defect has occurred between those scanning lines, but the occurrence position is, for example, the short-circuit defect position on the differential infrared image and the thin-film transistor liquid crystal substrate at that time. It can be easily specified from the positioning state data. After the short-circuit defect position is specified in this way, the short-circuit defect position can be removed by irradiating the short-circuit defect position with laser light. Similarly, the presence / absence of a short-circuit defect between signal lines can be detected, and the position of the short-circuit defect can be specified. However, the major difference from the case between the scanning lines is that the projection in the Y direction is performed. From the distribution shape, two signal lines that are in a heat-generating state are detected as a pair in a state where they are adjacent to each other.

Next, a method of identifying a short circuit defect position within a short circuit defective pixel address will be described. As shown in FIG. 6, in a thin film transistor liquid crystal substrate having a plurality of scanning line / signal line intersections and thin film transistors 7 themselves. The short-circuit defect may occur in each of the short-circuit candidate regions 73a to 73d.
Therefore, it is necessary to specify in which of the short-circuit candidate areas 73a to 73d the short-circuit defect has occurred (short-circuit position specification) when the wiring is corrected later.

By the way, the resistance value of the normal wiring is small, whereas the resistance value of the short-circuit defective portion is generally not so small, so that there is a slight temperature rise due to the current.
When this is detected by the infrared image detector 5, a value approximately proportional to the product of the emissivity γ and the square or the fourth power of the temperature T, that is, the product of the function R (T) of the object temperature T and the emissivity ε, An image having a value obtained by adding the product of the function R (Ta) of the ambient temperature and (1-ε) is obtained. The value of the emissivity γ is close to 1 for glass and close to 0 for wiring patterns such as chrome and aluminum. Therefore, it is necessary to correct this difference in emissivity due to the influence of the external environment.

While the resistance value in a normal wiring is small, that in a short-circuit defect portion is generally not so small, and a slight temperature rise due to the current occurs in that portion. Therefore, in the procedure as described above,
After detecting the infrared image before and after applying the voltage in the short-circuit defective pixel address, and by detecting the difference (or ratio) infrared image, a subtle change in image state due to minute heat generation in the short-circuit defective portion Momo can be detected with high sensitivity. By the way, detecting the difference (or ratio) infrared image itself is
As a result, an error of the infrared image detector 5 itself, for example, an error such as narcissus is compensated for at the same time.

More specifically, assuming that the short-circuited defective pixel address is already specified, the wiring pattern in the pixel address is sequentially positioned within the field of view of the infrared image detector 5. In addition, infrared images before and after the voltage application are detected. If the difference (or ratio) in the infrared image detected from those infrared images is greater than or equal to the set threshold value (predetermined value), there is a heat generation position due to a short circuit defect in the pixel address. The position of the short-circuit defect in the difference infrared image is detected after it is determined that the defect exists. The position of the short-circuit defect is detected as, for example, the position of the center of gravity in the area surrounded by the isotherm that is 0.2 ° C. lower than the position corresponding to the maximum value in the difference infrared image, or the difference infrared image thereof. Is projected in the X and Y directions within the set area, and the barycentric position may be detected from the Y and X coordinates of each area having a value equal to or larger than the set value.

Then, as shown in FIG. 9, the reference infrared image and the infrared image before voltage application are matched to obtain Y and X coordinates from a specific position such as an intersection of the scanning line and the signal line. Calculate as

In this way, even when there are a plurality of short-circuit defects in the short-circuit defective pixel address, the short-circuit defect can be detected in the state where the positions are specified. In addition to the short-circuit defect position coordinates in the difference infrared image thus obtained, the short-circuit candidate area where the short-circuit defect has occurred may be determined using the positioning coordinate data of the thin film transistor liquid crystal substrate.
As a result, the short circuit defect 3 shown in FIG.
In addition to the fact that the wire cutting position 9c exists, the wire cutting position 9c can be determined, and the wire cutting position 9c can be cut.
Incidentally, if the value in the difference infrared image is less than the set value, identify the short-circuit defect position by the visible image described later, or determine that there is no short-circuit defect in the short-circuit defective pixel address, The location of the short-circuit defect is not specified.

Further, the temperature distribution of the heat generating portion gradually decreases with distance from the center of heat generation.
When the infrared image is detected, if the infrared image detector 5 whose sensitivity is lowered toward the periphery of the light receiving part is used instead of the detector whose sensitivity is constant, the peak position of the heat generation center is more accurate. Required to.

In the in-field difference infrared image, in addition to the heat generation at the short-circuit defect portion, heat generation at the scanning line and the signal line caused by the short-circuit defect portion outside the in-field difference infrared image is simultaneously detected. However, by comparing the brightness at the edge of the difference infrared image, the position of the short-circuit defect portion present in the in-field difference infrared image can be correctly detected in a specified state.
FIG. 13 shows a situation in which the brightness at the edge portion of the difference infrared image within the visual field is compared. First, describing the case shown in FIG. 13A, the in-field difference infrared image is shown as being in a rectangular display frame, and the image portion corresponding to the short-circuit defect portion (position coordinate ( X ₁ , Y ₁ ) S ₁ is shown, and therefore, the scanning line image (1 end position coordinate Y ₁ ) and the signal line image (1 end part) where the image portion S ₁ is the intersection. The position coordinates X ₁ ) are both in a heat-generating state, but neither the scanning line image nor the signal line image extends in the direction of the other end, and the position coordinates of the other end cannot be detected. The image portion S ₁ can be identified as a short-circuit defect.
In the example shown in Fig. 2, there are two image portions S ₂ and S ₃ corresponding to the short-circuit defect portion in the vicinity of the in-field difference infrared image, and in this example, the scanning line image having the image portion S ₂ as the intersection portion. Then, both the signal line images having the image portion S ₃ as an intersection appear in the in-field difference infrared image. Therefore, the end position coordinates for the scanning line image in the in-field difference infrared image are obtained as Y ₁ and Y ₂ , and those for the signal line image are obtained as X ₁ and X ₂ , where Y ₁ = Y ₂ . When X ₁ = X _2, the scanning line image and the signal line image can be identified as a short circuit defect outside the in-field difference infrared image. Further, in FIG. 13C, an image portion S ₄ corresponding to the short-circuit defect portion exists in the in-field infrared image, and an image portion S ₅ corresponding to the short-circuit defect portion exists outside the in-field difference infrared image. Although it is, and so these, the image portion S ₄ image portion S ₁ and the circumstances in FIG. 7 (a) is the same, the image portion S ₄ are those capable determines that due to a short-circuit defect. Image part S
_With respect to the signal line image having ₅ as an intersection, since the end position coordinates are X ₁ = X ₂ , it can be determined that the signal line image is due to a short circuit defect outside the visual field. Incidentally, presence or absence of a short circuit defect at the position coordinates (X _1, Y ₂₎ is, it sets the window (broken line) in a state containing the position coordinates (X _1, Y ₂₎ in the interior, to repeat the above determination It should be done.

Further, in the above description, the image difference was taken in order to correct the emissivity, but design data of the emissivity was prepared and corrected by the size and sensitivity of the detector to calibrate this data, and after the voltage was applied. It is also possible to accurately obtain the temperature from one image. Furthermore, if the detector has geometric distortion,
It is also possible to detect and correct a wiring pattern such as a signal line.

The position of the short-circuit defect can be specified as described above, but it is also possible to specify it by the transmitted illumination image. This identification method will be described with reference to FIGS. 7A and 7B. When the resistance value of the short-circuit defective portion is small, the current due to the short circuit is sufficiently large, and it is possible to identify the short-circuited pixel address using the external wiring. There is, but is about the same as the wiring resistance,
If it is smaller than that, the heat generation at the short-circuited position is small, and this cannot be detected by using the infrared image. That is, it is not possible to specify the short-circuit position in the pixel.

Next, a method for identifying a short-circuit defect position in the short-circuit defective pixel address by a visible image will be described.

When the resistance value at the short-circuit defect portion is small, the current due to the short circuit is sufficiently large, and although the short-circuit defective pixel address can be specified by using the external wiring, the resistance value at the short-circuit defect portion is small. If the wiring resistance is equal to or less than the wiring resistance in the short-circuit defective pixel, the heat generation at the short-circuit defect position is small in the short-circuit defective pixel address, and the short-circuit defect can be detected even with the differential infrared image. You will not get it. That is, it is not possible to specify the short-circuit defect position within the short-circuit defective pixel. The situation is the same when the resistance value in the short-circuit defective portion is slightly larger than the wiring resistance in the short-circuit defective pixel. Therefore, although the short-circuit defective pixel address is specified by the method described above, it is judged that the short-circuit defect exists, though there is a degree of difference in the pixel address, but the difference infrared image When the value inside is less than the set value, the position identification of the short-circuit defect by the visible image is effective. Whether or not the position of the short-circuit defect is actually identified by the visible image is specifically, in the difference infrared image,
The maximum value in the image is the brightness α at that end.
The position of a short-circuit defect is first identified by a visible image when an additional condition such as (e.g., α = 2) times or less is satisfied.

Now, the short-circuit defect position identifying method based on a visible image will be specifically described. FIG. 7A shows a detected visible image in the transmitted illumination state with respect to the wiring pattern shown in FIG. Since the transmissive illumination is performed from the back of the thin film liquid crystal substrate, the metal wiring pattern can be detected as a silhouette image, that is, a binarized image as shown in the figure. On the other hand, the dictionary pattern shown in FIG. 7B is registered in advance in the dictionary pattern setting circuit 63 as a characteristic pattern, and the position coordinate data setting circuit 6 is used.
In FIG. 5, relative coordinate data of short-circuit candidate positions (positions of short-circuit candidate regions facing the table) 74a to 74d and wiring cutting positions 9a to 9d with the position 77 of the dictionary pattern as the origin are preset. There is. Therefore, if the position 77 of the dictionary pattern in the detected visible image is known, the short circuit candidate positions 74a to 74d and the wiring cut positions 9a to 9d in the detected visible image are also uniquely determined. In the short-circuit defect position identification by the visible image, the wiring pattern in the short-circuit defective pixel address is inspected in the state where the detection positions are sequentially shifted, but the position 77 of the dictionary pattern in the detected visible image is the position of the thin film transistor liquid crystal substrate. The position 77 varies depending on the positioning state, but the position 77 is obtained by pattern matching between the sequentially detected visible image and the dictionary pattern. That is, every time when a visible image is detected under the transmitted illumination state, the pattern matching between the detected visible image and the dictionary pattern indicates that the positioning coordinate in the state where the dictionary pattern is the best match in the visible image. From the position 77 is obtained. Therefore, the coordinate data of the short-circuit candidate positions 74a to 74d and the wiring cutting positions 9a to 9d in the visible image can be calculated from the position 77.

On the other hand, the position of the short-circuit defect is obtained from the visible image detected from above, that is, the grayscale image in this example. By performing the pattern matching of the grayscale image pattern at the short-circuited defective pixel address with that at the adjacent pixel address, the coordinates in the mismatched pattern portion can be detected. Specifically, in the pattern matching, the grayscale image at each of the two pixel addresses adjacent to the short-circuit defective pixel address is displaced from the short-circuit defective pixel address by one pixel pitch in the horizontal direction or in the vertical direction. Although it can be detected, a difference image between each of these two grayscale images and the grayscale image before shifting, that is, the grayscale image at the short-circuit defective pixel address is obtained, and two difference images are obtained. When a mismatch pattern portion having a value equal to or larger than the set value is commonly detected, the position coordinates at that portion may be detected as the short circuit defect position. From this, the short-circuit candidate position 74a
The shortest candidate position where the short-circuit defect actually occurs is determined to be the one having the shortest distance to the short-circuit defect position out of ~ 74d. This proves that the short-circuit 3 shown in FIG. 6 exists in the short-circuit candidate region 73c, and the wiring cutting position 9c can be determined from the short-circuit candidate region 73c as the wiring cutting position, as in the above-described embodiment. is there. As described above, in this example, the coordinate data to be set and stored in advance has the short-circuit candidate positions 74a to 74d and the wiring cutting positions 9a to 9 when the position 77 of the dictionary pattern is the origin.
In addition to only d, the short-circuit defect position can be easily specified. Then, after the wiring cutting position is determined by the above-mentioned short circuit defect position specifying method, the short circuit defect can be removed and corrected by cutting the wiring cutting position using an energy beam such as a laser beam. . In the above description, the visible image in the transmitted illumination state is used for detecting the position of the wiring pattern, but the position of the wiring pattern can be detected from the visible image in the bright field illumination state.

Although the present invention has been described above, the present invention can be similarly applied to the presence or absence of the defect and the position specification thereof if the object other than the thin film transistor substrate is accompanied by heat generation due to some defect factor. Obviously it is.

Finally, FIG. 8 shows an example of the detected image when the short-circuited pixel address is specified.

Incidentally, in the above-mentioned embodiment of the thin film transistor liquid crystal substrate inspecting apparatus, the case where the inspection of the short circuit defect and the correction of the wiring are carried out by one apparatus has been described, but the defect inspection and the wiring correction are carried out by the separate apparatuses. Of course, it is okay. Further, it goes without saying that a short circuit between the signal lines and between the scanning lines can be inspected by the same method.

[0080]

As described above, according to the present invention, various short-circuit defect defects in the wiring of the thin film transistor liquid crystal substrate can be detected with high sensitivity. Further, the contact for the defect inspection is only the voltage application to the external wiring, and the inspection can be performed without contacting the substrate body. Furthermore, it is possible to identify a short-circuit defect device even for a substrate on which a plurality of thin film transistors or a plurality of scanning line / signal line intersections are formed for each pixel of a liquid crystal display, and a short circuit defect exists. The substrate can easily be modified. As a result,
Various short-circuit defects existing on the thin film transistor liquid crystal substrate can be detected with high sensitivity and in a non-contact manner with the substrate, and the wiring can be corrected in parallel with such inspection. The yield of the thin film transistor liquid crystal substrate can be significantly improved.

[Brief description of drawings]

FIG. 1 is a diagram showing a general example of an electrical wiring configuration of a thin film transistor liquid crystal substrate.

2A and 2B are diagrams for explaining the types of short-circuit defects and a short-circuit defect correction method.

FIG. 3 is a diagram illustrating a conventional inspection method for confirming the presence or absence of a short circuit defect.

FIG. 4 is a diagram for explaining a short-circuited pixel address specifying method according to the present invention.

FIG. 5 is a diagram showing a configuration of an example of a thin film transistor liquid crystal substrate inspection device according to the present invention.

FIG. 6 is a diagram illustrating a method of identifying a short circuit position in a pixel.

7A and 7B are diagrams for explaining a short-circuit defect position specifying method using a transmitted illumination image.

FIG. 8 is a diagram showing an example of a detected image when specifying a short-circuited pixel address.

FIG. 9 is a diagram showing a method of measuring a heat generation position.

10 is a diagram for explaining an example of infrared image detection timing in the inspection apparatus shown in FIG.

11 is a diagram for explaining a difference based on an infrared image detected at the infrared image detection timing shown in FIG. 10: a qualitative feature of the infrared image.

FIG. 12 is a diagram for explaining a difference based on the detected infrared image without depending on the infrared image detection timing shown in FIG. 10: a qualitative defect of the infrared image.

13A to 13C show a signal line image or a scanning line image in a field-of-view difference infrared image relatively prominently when a short circuit defect position in a short circuit defective pixel is specified. It is a figure for demonstrating the processing method in a case.

[Explanation of symbols]

 3 ... Short circuit defect, 9a, 9d ... Wiring cutting position, 30 ... Thin film transistor substrate, 35 ... Power supply (DC, AC) 36 ... Probe, 37 ... Objective lens, 38, 40 ... Dichroic mirror, 39, 45, 47, 49 ... Lens, 41 ... Aperture, 42 ... Beam expander, 43 ... Laser, 44 ... Half mirror, 48 ... Visible image detector, 55 ... Difference image detection circuit, 56 ... Coordinate detection circuit, 57 ... Reference infrared image , 61 ... Binarization circuit, 62 ... Pattern matching circuit, 63 ... Dictionary pattern, 64 ... Short circuit candidate position calculation circuit, 65 ... Coordinate data, 66 ... Memory, 67 ... Pattern matching circuit, 69 ... Short circuit position determining circuit, 74a -74d ... Short-circuit candidate position, 77 ... Dictionary pattern position.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location G09G 3/36 7319-5G

Claims (30)

[Claims] 1. A scan line is formed by applying a voltage between a scan line and a signal line on a thin film transistor liquid crystal substrate and monitoring a change in a heat generation state due to a current flowing between the scan line and the signal line by an infrared image. A method of inspecting a thin film transistor liquid crystal substrate, which comprises detecting a short-circuit defect existing between signal lines. 2. A voltage is applied between a scanning line and a signal line in a state where a plurality of scanning lines and a plurality of signal lines on a thin film transistor liquid crystal substrate are electrically commonly connected at one terminal. A method for inspecting a thin film transistor liquid crystal substrate, characterized by detecting a short-circuit defect existing between a scanning line and a signal line by monitoring a change in a heat generation state caused by a current flowing between the scanning line and the signal line by an infrared image. . 3. A voltage is applied between the scanning line and the signal line in a state where a plurality of scanning lines and a plurality of signal lines on a thin film transistor liquid crystal substrate are electrically connected commonly at one terminal, and a voltage is applied between the scanning line and the signal line. By detecting the change in the heat generation state due to the current flowing between the scanning line and the signal line with an infrared image, the scanning line is electrically connected when detecting a short-circuit defect existing between the scanning line and the signal line. For the scanning line existing between the terminal and the pixel region, and the signal line existing between the terminal electrically connecting the signal line and the pixel region, the change in the heat generation state before and after the voltage application is changed by the infrared image. A method of inspecting a thin film transistor liquid crystal substrate, characterized in that a pixel address in which a short circuit defect has occurred is identified by monitoring. 4. A scanning line and a signal line are electrically connected to each other through a plurality of scanning lines and a plurality of signal lines on a thin film transistor liquid crystal substrate, and a voltage is applied between the scanning line and the signal line, When detecting a short-circuit defect existing between the scanning line and the signal line by monitoring the change in the heat generation state due to the current flowing between the scanning line and the signal line, the terminal that electrically connects the scanning line Of the scanning line existing between the pixel region and the pixel region and the signal line existing between the terminal electrically connecting the signal line and the pixel region, the change in the heat generation state before and after the voltage application is monitored by the infrared image. Therefore, after specifying the pixel address where the short-circuit defect occurs, the short-circuit defect occurs by monitoring the change in the heat generation state before and after the voltage application from the infrared image for the pixel at the specified address. Position Thin film transistor liquid crystal inspection method characterized by identifying a. 5. The method of inspecting a thin film transistor liquid crystal substrate according to claim 1, wherein the short-circuit defect is detected or the position of the short-circuit defect is identified by a difference or quotient (ratio) between infrared images before and after applying a voltage. . 6. The method for inspecting a thin film transistor liquid crystal substrate according to claim 2, wherein the short-circuit defect is detected or the position of the short-circuit defect is identified by a difference or quotient (ratio) between infrared images before and after applying a voltage. . 7. The method of inspecting a thin film transistor liquid crystal substrate according to claim 3, wherein the short-circuit defect is detected or the position of the short-circuit defect is identified by a difference or a quotient (ratio) between infrared images before and after applying a voltage. . 8. The method for inspecting a thin film transistor liquid crystal substrate according to claim 4, wherein the short-circuit defect is detected or the position of the short-circuit defect is identified by the difference or quotient (ratio) between the infrared images before and after the voltage application. . 9. A position where a short-circuit defect has occurred is specified by referring to a visible image of a wiring pattern of a thin film transistor liquid crystal substrate for a pixel address where the short-circuit defect has occurred. Thin film transistor liquid crystal substrate inspection method. 10. The method for inspecting a thin film transistor liquid crystal substrate according to claim 2, wherein the detection sensitivity is lowered toward the periphery of the light receiving portion during infrared image detection. 11. A heat generation position is accurately calculated by calculating a positional relationship between an infrared image and a reference image before voltage application, and a voltage is applied between a scanning line and a signal line of a thin film transistor liquid crystal substrate, Based on the calculated heat generation position, the change in the heat generation state due to the current flowing through the short circuit defect portion of the scanning line and the signal line is detected from the infrared image to detect the short circuit defect existing between the scanning line and the signal line. A thin film transistor liquid crystal substrate inspection method, comprising: 12. The method of inspecting a thin film transistor liquid crystal substrate according to claim 11, wherein the scanning line and the signal line of the thin film transistor liquid crystal substrate are electrically connected at one terminal. 13. The method for inspecting a thin film transistor liquid crystal substrate according to claim 12, wherein a position where a short-circuit defect has occurred is specified by detecting a change in a heat generation state before and after applying a voltage from an infrared image. . 14. The method of inspecting a thin film transistor liquid crystal substrate according to claim 11, wherein the reference image is an infrared image before applying a voltage, and is an image of a transistor portion or an intersection of a scanning line and a signal line. . 15. The method of inspecting a thin film transistor liquid crystal substrate according to claim 11, wherein the positional relationship between the infrared image and the reference image before voltage application is calculated by image matching. 16. A thin film transistor liquid crystal substrate, between scanning lines / signal lines, between scanning lines, or in a state in which a voltage is applied between the scanning lines / signal lines, between the scanning lines, or between the signal lines. Changes in the heat generation state due to the current flowing through
By detecting from the difference or quotient between the infrared image when the voltage is applied and the infrared image when the voltage is not applied,
A method of inspecting a thin film transistor liquid crystal substrate for detecting a short-circuit defect existing between scanning lines / signal lines, between scanning lines, or between signal lines. 17. An infrared image is detected after a lapse of a predetermined time from the time when a voltage is applied between scanning lines / signal lines, between scanning lines or between signal lines in a thin film transistor liquid crystal substrate, while the application of voltage is stopped. An infrared image is detected after a predetermined time has passed from the time point, between the scanning lines and the signal lines, between the scanning lines,
Alternatively, by detecting the change in the heat generation state due to the current flowing between the signal lines from the difference or quotient between the infrared image in the voltage applied state and the infrared image in the voltage applied state, the scanning line / signal is detected. A method of inspecting a thin film transistor liquid crystal substrate for detecting a short circuit defect existing between lines, between scanning lines or between signal lines. 18. An infrared image is detected after a predetermined time elapses from the time when a voltage is applied between scanning lines / signal lines, between scanning lines or between signal lines in a thin film transistor liquid crystal substrate, while the application of voltage is stopped. An infrared image is detected after a predetermined time has passed from the time point, between the scanning lines and the signal lines, between the scanning lines,
Alternatively, the change in the heat generation state due to the current flowing between the signal lines is calculated from the difference between the infrared image when the voltage is applied and the infrared image when the voltage is not applied, or the quotient, between the scanning line and the signal line, and the scanning. When detecting a short-circuit defect existing between lines or between signal lines, the infrared image detection timing in each of the voltage application state and the voltage application stop state is set to the detection current value in the voltage application state in advance or the detection infrared A method for inspecting a thin film transistor liquid crystal substrate, which is determined based on the amount of heat generated on an image. 19. A thin film transistor liquid crystal substrate, between scanning lines / signal lines, between adjacent scanning lines, or in a state where a voltage is applied between the signal lines, between the scanning lines / signal lines, between the scanning lines,
Alternatively, when the change in the heat generation state due to the current flowing between the signal lines is detected from the difference between the infrared image in the voltage applied state and the infrared image in the voltage applied state or the quotient, the value is set. A method of inspecting a thin film transistor liquid crystal substrate for detecting a short circuit defect existing between scanning lines / signal lines, between scanning lines, or between signal lines by comparing with a threshold value. 20. An infrared image is detected after a lapse of a predetermined time from the time when a voltage is applied between scanning lines / signal lines, between scanning lines or between signal lines in a thin film transistor liquid crystal substrate, while the application of voltage is stopped. Detection of an infrared image is repeated a plurality of times after a lapse of a predetermined time from the time point, and a change in a heat generation state due to a current flowing between the scanning lines and the signal lines, between the scanning lines, or between the signal lines is detected by a voltage. By detecting from the difference or quotient between the multiple superimposed infrared images in the applied state and the multiple superimposed infrared images in the stopped state of voltage application, scanning lines, signal lines, scanning lines Alternatively, a method of inspecting a thin film transistor liquid crystal substrate for detecting a short circuit defect existing between signal lines. 21. A plurality of scanning lines and signal lines on a thin film transistor liquid crystal substrate are electrically connected in common on one terminal side, and a predetermined time elapses from the time when a voltage is applied between the scanning lines and the signal lines. While the infrared image outside the pixel area is detected later, the infrared image outside the pixel area is detected after a predetermined time elapses from the time when the voltage application is stopped, and the scanning line and the signal line relating to the change in the heat generation state. By detecting the difference between the infrared image in the voltage applied state and the infrared image in the voltage applied state or the quotient to detect the pixel address where the short circuit defect occurs. Board inspection method. 22. A plurality of scanning lines and signal lines on a thin film transistor liquid crystal substrate are electrically connected in common on one terminal side, and a predetermined time elapses from the time when a voltage is applied between the scanning lines and the signal lines. While the infrared image outside the pixel area is detected later, the infrared image outside the pixel area is detected after a predetermined time elapses from the time when the voltage application is stopped, and the scanning line and the signal line relating to the change in the heat generation state. By detecting the difference between the infrared image in the voltage application state and the infrared image in the voltage application stop state, or the quotient, to identify the pixel address where the short-circuit defect occurs, At the address, the difference between the infrared image detected after a lapse of a predetermined time from the time when the voltage was applied between the scanning line and the signal line and the infrared image detected after a lapse of the predetermined time from the time when the voltage application was stopped. Or as a quotient, Detecting a short circuit defect location by comparing a set threshold value, the thin film transistor liquid crystal substrate inspection method which is adapted to detect a short circuit defect at the pixel address. 23. A plurality of scanning lines and signal lines on a thin film transistor liquid crystal substrate are electrically connected in common on one terminal side, and a predetermined time elapses from the time when a voltage is applied between the scanning lines and the signal lines. While the infrared image outside the pixel area is detected later, the infrared image outside the pixel area is detected after a predetermined time elapses from the time when the voltage application is stopped, and the scanning line and the signal line relating to the change in the heat generation state. By detecting the difference between the infrared image in the voltage application state and the infrared image in the voltage application stop state or the quotient, and after the pixel address in which the short-circuit defect has occurred is identified, At the pixel address, an infrared image detected after a lapse of a predetermined time from the time when the voltage is applied between the scanning line and the signal line, and an infrared image detected after a lapse of the predetermined time from the time when the voltage application is stopped Detect as difference or quotient , Inspecting the thin film transistor liquid crystal substrate for detecting the short-circuit defect position by comparing with a set threshold value in consideration of the brightness of the edge in the difference infrared image, and detecting the short-circuit defect at the pixel address Method. 24. A plurality of scanning lines and signal lines on a thin film transistor liquid crystal substrate are electrically connected in common on one terminal side, and a predetermined time elapses from the time when a voltage is applied between the scanning lines and the signal lines. While the infrared image outside the pixel area is detected later, the infrared image outside the pixel area is detected after a predetermined time elapses from the time when the voltage application is stopped, and the scanning line and the signal line relating to the change in the heat generation state. Is detected from the difference or quotient between the infrared image when the voltage is applied and the infrared image when the voltage is not applied, and the pixel address where the short-circuit defect occurs is identified, and the scanning line / signal is detected. Detected as the difference or quotient between the infrared image detected after a lapse of a predetermined time from the time when the voltage was applied between the lines and the infrared image detected after a lapse of the predetermined time from the time when the voltage application was stopped. Difference at the pixel address If there is no image portion above the set threshold value in the outside image, and if there is no image portion above the set threshold value in the difference infrared image at the pixel address, then at the pixel address A method for inspecting a thin film transistor liquid crystal substrate, wherein a wiring pattern position is detected from a visible image of the pixel address, and a wiring pattern at the pixel address is compared with a wiring pattern at an adjacent pixel address to detect a short circuit defect position. 25. A thin film transistor liquid crystal substrate having a means for applying a voltage between a scanning line and a signal line and an infrared image detecting means, wherein heat is generated by a current flowing through a short circuit defect portion between the scanning line and the signal line before and after the voltage is applied. A thin film transistor liquid crystal substrate inspection device, characterized in that a change in state is detected by an infrared image detecting means. 26. When a voltage is applied between the scanning line and the signal line, one terminal of each of the plurality of scanning lines and the plurality of signal lines in the thin film transistor liquid crystal substrate is electrically connected in common, 26. The thin film transistor liquid crystal substrate inspection device according to claim 25, wherein a voltage is applied between the scanning line and the signal line. 27. A scanning line existing between a terminal electrically connecting a scanning line and a pixel region, and a signal line existing between a terminal electrically connecting a signal line and a pixel region,
27. The thin-film transistor liquid crystal substrate inspection device according to claim 26, wherein a pixel address in which a short-circuit defect has occurred is specified by detecting a change in a heat generation state before and after applying a voltage with an infrared image detecting means. 28. In order to optically detect an image at an arbitrary position on the thin film transistor liquid crystal substrate, the thin film transistor liquid crystal substrate is set at an arbitrary position in X, Y, Z directions and a rotational position θ in the XY horizontal plane. A stage system to be mounted, a voltage application system for applying a voltage between scanning lines / signal lines, between scanning lines or between signal lines in the thin film transistor liquid crystal substrate mounted on the stage system, and the above-mentioned stage system. An illumination system for illuminating the thin film transistor liquid crystal substrate with visible light in order to detect a wiring pattern at any position on the mounted thin film transistor liquid crystal substrate as a visible image, and a thin film transistor liquid crystal substrate mounted on the stage system. An infrared image at an arbitrary position is detected after a predetermined time has passed from the voltage application start point and the voltage application stop point, respectively.
Placed on the above-mentioned stage system and an infrared image detection processing system that performs the predetermined image processing to identify the presence or absence of a short-circuit defect, specify the short-circuit defect occurrence pixel address and the short-circuit defect position within the short-circuit defect occurrence pixel address. After detecting the wiring pattern at any position on the thin film transistor liquid crystal substrate as a visible image,
An inspection apparatus for a thin film transistor liquid crystal substrate, comprising at least a visible image detection processing system for specifying a short-circuit defect position within a short-circuit defect occurrence pixel address by performing predetermined image processing. 29. The thin film transistor liquid crystal substrate inspection / repair device according to claim 25, further comprising short-circuit defect repairing means for irradiating the specified short-circuit defect with an energy beam to remove the short-circuit defect. . 30. The thin film transistor liquid crystal according to claim 1, wherein the specified short circuit defect is irradiated with an energy beam to remove the short circuit defect. Board inspection / correction method.