JP3568753B2 - Inspection method and inspection device for defective electrode on substrate - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method and an apparatus for inspecting a defective electrode on a substrate for inspecting a defect of an electrode formed on a glass substrate or the like of a liquid crystal display device. The present invention relates to a defective electrode inspection method and an inspection apparatus.
[0002]
[Prior art]
2. Description of the Related Art In recent years, as a display device used in a computer or the like, a matrix type display device using liquid crystal has been widely used in place of a display device using a cathode ray tube. In such devices, in order to increase the amount of data that can be displayed on the screen at one time, the development of large-screen or high-resolution liquid crystal display devices is also progressing, and the electrodes formed on the substrate are becoming smaller patterns. ing. Therefore, the occurrence of defective substrates increases due to a decrease in yield, and the defective substrates are repaired. Further, in order to reduce the cost of the liquid crystal display device, a defective substrate is repaired.
[0003]
A liquid crystal display device as described above uses a matrix type liquid crystal substrate. In a normal matrix type liquid crystal substrate, a transparent X electrode and a transparent Y electrode made of ITO or the like are formed on two glass substrates by etching, respectively, and the electrode forming surfaces of each substrate are arranged to face each other in a matrix. A liquid crystal is sealed between the glass substrates.
[0004]
As described above, when the electrode is formed on a glass substrate, defects illustrated in FIGS. 7B and 7C may occur. Such a defect is caused by the inclusion of a foreign substance during the etching process or a defect in the etching process. FIG. 7B shows a state in which a part of an adjacent line is in contact with a non-defective product in FIG. A short defect (C) indicates a disconnection (open) defect in which a part of the same line is missing.
[0005]
With respect to the short-circuit defect of the above (B), it was possible to specify the line of the short-circuit defect and the position of the line where the short-circuit defect occurred by using a conventionally used inspection apparatus. On the other hand, for the disconnection defect of (C), the visual processing of an image processing apparatus or an operator relies.
[0006]
[Problems to be solved by the invention]
However, for the disconnection defect shown in FIG. 7C, it is possible to specify which line of the electrode has the disconnection defect, but the position in the length direction cannot be specified due to the measurement principle.
For this reason, the line of the electrode 3 is monitored by a method based on image processing using (1) a camera and a monitor, and (2) a worker is visually monitored.
[0007]
In the case of the image processing of the above (1), the apparatus itself is very expensive because a dedicated camera and monitor are used, and it is not easy to set conditions such as lighting for illuminating the substrate. Had problems such as slow processing.
In addition, since the liquid crystal electrode pattern is formed by a very fine pattern, it requires a very large amount of time to perform the inspection in the case of visual inspection in the above (2). In addition, there was a risk of overlooking the defect and lacked certainty. Further, the above-mentioned inspection is very nervous, and there is a problem that a considerable burden is imposed on an operator.
[0008]
The present invention has been made in order to solve the above-mentioned problem, and it is an object of the present invention to specify the position in the length direction of a disconnection defect on a substrate on which a condition can be easily set and an inexpensive apparatus having a short inspection time can be specified. It is an object of the present invention to provide a defective electrode inspection method and an inspection apparatus.
[0009]
[Means for Solving the Problems]
The method for inspecting a defective electrode on a substrate according to the present invention is a method for inspecting a defective electrode on a substrate to specify the location of a disconnection defect of an electrode formed on the substrate,
The first conductor is brought into contact with one electrode line to be inspected, the second conductor is brought into contact with the electrode line to be inspected and another electrode line adjacent to the electrode line, and the first conductor monitors the current value or voltage value between said second conductor to identify an electrode occurring defects,
While the first conductor is in contact with the specified electrode line, the second conductor is moved along the specified electrode line and another electrode line adjacent to the specified electrode line, and A change in a current value or a voltage value between the first conductor and the second conductor at the time is monitored, and a defective portion of the specified electrode line is specified .
[0010]
By the above means, the first conductor is brought into contact with one end in the longitudinal direction of the electrode and the second conductor is brought into contact with the other end, and the continuity between the two conductors on the electrode is inspected. At this time, if a disconnection defect occurs in the electrode, no current flows between the two conductors, and if a disconnection defect does not occur in the electrode, a current flows between the two conductors. By monitoring the current value or the voltage value generated in the circuit, it is possible to identify which line of the electrode has the disconnection defect.
[0012]
When the current value or the voltage value between the conductors is monitored and the position of the electrode having the disconnection defect in the line direction is specified, the second conductor moves while sliding on the electrode. When the two conductors are present on different sides of the disconnection defect, no change in the current value or the voltage value is observed, and when the second conductor moves and both conductors are present on the same side, the two conductors conduct to each other. The current value or voltage value changes. As described above, the exact position of the defective electrode is specified.
[0013]
In this case, it is preferable that the second conductor has a brush shape .
[0014]
Since the electrodes formed on the liquid crystal display substrate are extremely fine, if the movable conductor is a needle-like conductor when inspecting a defective electrode, the conductor may fall out of the electrode line during the movement, resulting in an inspection error. Occurred, and the defect position was not reliably determined. Therefore, a highly accurate correction device was required for positioning the substrate. However, as described above, one conductor was formed in a brush shape, and the adjacent electrode was formed. With such a configuration, a high-precision correction device is not required for positioning the substrate, and an inspection error can be prevented.
[0015]
Further, the present invention is an inspection apparatus for a defective electrode on a substrate for specifying the position of a disconnection defect of an electrode formed on the substrate,
A first conductor in contact with one end of a single conductive Gokura inn with line breaking, and a second conductor in contact with the adjacent other electrode lines to the electrode lines and the electrode lines of line breaking, the it is characterized in that it has a moving device for moving along the second guide member to the electrode line with a line breaking, and a test circuit for monitoring the current or voltage between both conductors. In this case, it is preferable that the second conductor has a brush shape.
[0016]
With the above-described device, an inexpensive device can be configured without using an expensive device, and the inspection can be performed reliably and quickly.
[0017]
Note that the substrate of the present invention is represented by a glass substrate of a liquid crystal display device, but may be another IC mounting substrate or the like, and the electrode is a transparent electrode such as ITO in the case of a liquid crystal display device. However, another copper foil or gold foil electrode may be used.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a method for inspecting a defective electrode on a substrate according to the present invention will be described with reference to FIGS. FIG. 1 is an explanatory view showing the entire device from inspection to repair of a substrate. FIG. 2A is a top view showing the positional relationship between the substrate and the inspection device, and FIG. 2B is a side view and a circuit diagram thereof. is there.
Normally, as shown in FIG. 7, a substrate used in a liquid crystal display device has an X electrode or a Y electrode 3 made of a material such as ITO formed on a glass substrate 2 by etching at regular intervals in a line shape. . In some cases, for example, a foreign matter is mixed into the electrode 3 during the formation of the electrode by the etching process, so that a disconnection defect portion 6 as shown in FIG.
[0019]
An apparatus for specifying the position of the disconnection defect 6 as described above is the inspection apparatus 8 shown in FIG.
The inspection device 8 includes an inspection probe 8a as a first conductor, an inspection brush 8b as a second conductor, and an inspection circuit 8c.
The glass substrate 2 on which the electrodes 3 are formed is placed on a table 12 shown in FIG. 1 and the inspection of the electrodes 3 is performed. After the glass substrate 2 is positioned, an inspection probe 8a and an inspection brush 8b composed of two conductors are arranged at both ends of the line of the electrode 3. If necessary, the position of the glass substrate 2 can be finely adjusted by moving the table 12 in the XY direction or the θ direction.
[0020]
The tip of the inspection probe 8a is formed in a needle shape. Further, the inspection brush 8b is formed wide so as to straddle the line of the adjacent electrode 3, so that even if the inspection brush 8b is slightly displaced from the line of the electrode 3, an inspection error does not occur. It is preferable to use a conductive brush having a soft tip so that the electrode 3 is not damaged.
The inspection probe 8a and the inspection brush 8b are connected to an inspection circuit 8c. The inspection circuit 8c has a power source E, a resistor R, and a voltmeter for measuring a voltage V flowing through the resistor R. Both ends of the inspection circuit 8c are connected to the inspection probe 8a and the inspection brush 8b, respectively. Have been. The resistor R has a resistance sufficiently larger than that of the electrode 3.
[0021]
When the electrodes 3 are formed normally, a current I flows between the electrodes 3 to make the circuit conductive, and a voltage V (= IR) is generated at the resistor R. On the other hand, when the disconnection defect 6 exists in the electrode 3, the entire circuit does not conduct, and no current flows through the resistor R, so that no voltage is generated. By monitoring the presence or absence of this voltage value (V) on a monitor, it is possible to specify in which line of the electrode 3 the disconnection defect 6 occurs.
Subsequently, the defect position in the length direction of the electrode 3 is specified.
[0022]
As shown in FIGS. 2A and 2B, the inspection brush 8b starts moving in the direction of the inspection probe 8a, that is, in the direction from (1) to (4), and the position where the disconnection defect portion 6 is generated is determined. inspect. In this case, the inspection brush 8b moves while sliding on the electrode 3. At this time, in the state (2) located before the disconnection defect portion 6, no voltage is generated in the resistor R, and a voltage is generated in the state (3) at the time when the resistance R is exceeded. A voltage change occurs at the boundary, and the position of the disconnection defect portion 6 is specified.
As described above, the line at which the disconnection defect portion 6 occurs and the position of the line can be accurately specified.
[0023]
As shown in FIG. 1, the inspection device 8 is connected to a moving device 13c and a control device 11, and can move the inspection probe 8a and the inspection brush 8b by the moving device 13c. The operation is controlled, and the position data of the disconnection defect portion 6 is stored, and this data is sent to the next device for repair.
FIG. 1 shows the entire apparatus from inspection to repair of the glass substrate 2 on which the electrodes 3 are formed, and is composed of an inspection device 8, a transfer device 4, a heating device 5, and a control device 11.
[0024]
When the disconnection defect portion 6 is specified by the above-described method and apparatus, the transfer device 4 is operated next.
The transfer device 4 includes a transfer probe 4a, a moving device 13a, and a plate paste 1c. The transfer device 4 is controlled by the control device 11 so that the transfer probe 4a can be appropriately moved between the transfer probe 4a and the disconnection defect portion 6. The plate paste 1c is formed of a base 4d and a plate frame 4c, and the paste 1 is poured into the plate frame 4c and is flattened by a squeegee or the like to form a plate paste 1c.
Further, the heating device 5 is constituted by a semiconductor laser 5a and a moving device 13b.
[0025]
FIG. 3 shows a process of repairing the substrate having the disconnection defect portion 6.
The paste 1 is transferred to the disconnection defect portion 6 by the transfer probe 4a, and subsequently the paste 1 is baked by the semiconductor laser 5a. The semiconductor laser 5a is connected to the moving device 13b, and is controlled by the control device 11 so that the semiconductor laser 5a can freely move to the upper part of the paste 1 formed in the disconnection defect portion 6.
[0026]
The operation of the transfer probe 4a will be described with reference to FIG. 4. First, the transfer probe 4a is moved from the initial state (i) onto the plate paste 1c (ii) and is lowered (iii). Next, the transfer probe 4a is pushed in until it reaches the bottom of the plate paste 1c, and by raising the transfer probe 4a, a fixed amount of paste 1 is transferred to the tip of the transfer probe 4a. At this time, as shown in FIG. 5A, a coil spring 7 is provided as an elastic body inside the transfer probe 4a. When the transfer probe 4a reaches the bottom of the plate paste 1c, the coil spring 7 7, the transfer probe 4a is pressed by a force F from above. Next, the transfer probe 4a is moved onto the disconnection defect 6 (iv) and lowered (v). By raising the transfer probe 4a, the paste 1 is separated from the transfer probe 4a, and the paste 1 is transferred to the disconnection defect portion 6, and returns to the initial state (i) (vi).
[0027]
The material of the transfer probe 4a is preferably beryllium-copper, and as shown in FIG. 5 (B), the tip of the transfer probe 4a has a flat shape 4b to facilitate transfer. Is preferred.
The use of the transfer probe 4a as described above eliminates the need for a highly accurate positioning mechanism or control. When the amount of the paste 1 to be transferred is changed, it can be easily coped with by changing the depth of the plate paste 1c.
[0028]
The paste 1 composed of the metal organic compound is not a gold paste based on gold powder, but is formed by bonding gold atoms to an organic substance, and is entirely formed of a liquid paste. As such a paste 1, it is preferable to use a MOD (metallo organic deposition) type gold paste based on a gold resinate, and among them, a low temperature firing paste is preferable.
The unrepaired substrate 10 made of the paste 1 transferred to the disconnection defect portion 6 as described above is sent to the step of FIG. 3B, where the paste 1 is baked.
[0029]
A semiconductor laser 5a is used as a heating source of the heating device 5 used in this baking, and baking is performed by irradiating near infrared rays having a wavelength of about 810 nm. Although not shown, the semiconductor laser 5a is obtained by unitizing a plurality of semiconductor elements, and laser light emitted from each element is bundled using a glass fiber and condensed by a lens unit. It is formed so that the object can be irradiated with light.
[0030]
When the semiconductor laser 5a as described above is used, as shown by the arrow in FIG. 3B, the portion irradiated to the paste 1 absorbs the laser beam, generates heat, and is heated. The other portions are not absorbed by the laser beam and pass through the electrode 3 and the glass substrate 2. That is, the semiconductor laser 5a uses an element that emits near-infrared rays, and the paste 1 illustrated above absorbs near-infrared rays because the paste has a black color. Therefore, only the transferred portion of the paste 1 is subjected to the heat treatment, and the other portions of the glass substrate 2 do not generate heat, and the glass substrate 2 is not damaged.
Further, in the semiconductor laser 5a, the output intensity of the laser beam can be easily controlled, whereby the disconnection defect portion 6 can be obtained as a high quality fired portion in firing the paste 1.
[0031]
As an example for obtaining the high-quality fired portion described above, a profile shown in FIG. 6 can be mentioned. That is, first, after rising to a predetermined output (0 to 8 seconds), a low output is maintained for a fixed time stepwise (8 to 16 seconds, 16 to 24 seconds). Of the solvent in the paste 1 is removed. After that, by maintaining the high output for a certain time (24 to 34 seconds), the main firing is performed to deposit the metal component, and after the firing is completed, the output is gradually lowered (34 to 42 seconds) to cool down. Done. Through the above-described steps, it is possible to obtain a high-quality metal thin film 1a in which the deposited portion of the metal formed in the disconnection defect portion 6 is crack-free and dense. The above profile is an example, and can be changed as appropriate according to the amount of the paste 1 to be transferred.
[0032]
As described above, the disconnection defect portion 6 is repaired, a metal thin film 1a made of a metal precipitate as shown in FIG. 3C is obtained, and the repaired substrate 10a is obtained.
As described above, the paste 1 made of a metal organic compound is transferred to the disconnection defect portion 6 generated in the electrode 3 on the glass substrate 2 by the transfer device 4, and the portion of the paste 1 is made of the semiconductor laser 5a. The baking is performed by the heating device 5, and only the metal component in the paste 1 is precipitated to repair the defective portion.
[0033]
【The invention's effect】
According to the method for inspecting a defective electrode on a substrate of the present invention, the position of the defective electrode on the substrate can be specified not only in the line direction but also on the line.
[0034]
Further, the inspection apparatus of the present invention can be constituted by an inexpensive apparatus including two movable conductors and a simple inspection circuit, and can surely and quickly inspect. Further, by using the above-described inspection device, the worker can surely find the defect without overlooking the defect, and reduce the burden on the worker by eliminating the need for extremely nervous work. Is what you can do.
[0035]
Further, by using such an inexpensive inspection device and increasing the working speed, the cost of the liquid crystal display substrate can be reduced.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing an entire apparatus composed of an inspection apparatus of the present invention and a repair apparatus associated therewith;
2A is a plan view showing an arrangement of the inspection apparatus, FIG. 2B is a side view thereof, and a circuit diagram connected to the inspection apparatus;
FIGS. 3A, 3B, and 3C are process diagrams showing a method for repairing a defective electrode; FIGS.
FIG. 4 is an explanatory diagram showing the operation of the transfer probe.
5A is a front view showing the structure of a transcription probe, FIG. 5B is an enlarged view,
FIG. 6 is a profile showing a relationship between time and output in firing,
7A and 7B are plan views showing electrodes formed on a substrate, wherein FIG. 7A shows a normal state, FIG. 7B shows a short-circuit defect, and FIG.
[Explanation of symbols]
2 Glass substrate 3 Electrode 6 Disconnection defect 8 Inspection device 8a Inspection probe 8b Inspection brush 8c Inspection circuit E Power supply R Resistance V Voltage I Current

Claims (4)

A method for inspecting a defective electrode on a substrate to identify a location of a disconnection defect of an electrode formed on the substrate,
The first conductor is brought into contact with one electrode line to be inspected, the second conductor is brought into contact with the electrode line to be inspected and another electrode line adjacent to the electrode line, and the first conductor monitors the current value or voltage value between said second conductor to identify an electrode occurring defects,
While the first conductor is in contact with the specified electrode line, the second conductor is moved along the specified electrode line and another electrode line adjacent to the specified electrode line, and Monitoring a change in a current value or a voltage value between the first conductor and the second conductor at the time to identify a defective portion of the specified electrode line. Inspection method of electrode. 2. The method for inspecting a defective electrode on a substrate according to claim 1, wherein the second conductor has a brush shape . An inspection device for a defective electrode on a substrate that specifies the position of a disconnection defect of an electrode formed on the substrate,
A first conductor in contact with one end of a single conductive Gokura inn with line breaking, and a second conductor in contact with the adjacent other electrode lines to the electrode lines and the electrode lines of line breaking, the a moving device for moving along the second guide member to the electrode line with a disconnection defect inspection apparatus of the defect electrodes on the substrate, characterized in that it comprises a test circuit for monitoring the current or voltage between both conductors . The inspection device for a defective electrode on a substrate according to claim 3, wherein the second conductor is in a brush shape.

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