JP2000347217A - Method for correcting defect in active matrix substrate and production of liquid crystal panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To correct a short circuit defect between an upper electrode and a lower electrode due to a pinhole defect in an auxiliary capacitor part while the state of an active matrix substrate is present. SOLUTION: When a short circuit is produced between a lower electrode and an upper electrode due to a pinhole 12 of an insulating film 7 in an auxiliary capacitor part consisting of a common signal wiring 3 or a scanning wiring (lower electrode), and an insulating film 7 and a pixel electrode 5 (upper electrode), a part of the upper electrode 13 near the short circuit defect 12 is removed by irradiation of light energy. Since the defect is corrected in the state of the active matrix substrate before lamination with counter substrate, no influence is added to the refractive index or transmittance of a glass substrate or a color filter forming part or on the alignment of a liquid crystal, or defective products are not sent to the succeeding processes. By using a short wavelength laser of UV rays at <=360 nm wavelength, for example, by using the fourth order harmonic waves of a YAG laser, only the upper electrode near the short circuit defect can be removed with good accuracy without adding influences on the lower films.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an audio visual (AV) device such as a television set and an office automation (OA) such as a word processor.
on) The present invention relates to a method for repairing a defect when a short-circuit defect occurs in an auxiliary capacitance portion and a method for manufacturing a liquid crystal panel in an active matrix substrate used for an information terminal display device such as a device and a notebook personal computer.

[0002]

2. Description of the Related Art At present, liquid crystal display devices utilizing the electro-optical effect of liquid crystal for display devices include information terminal display devices such as notebook personal computers and OA.
It is used in various fields such as devices and AV devices.

This liquid crystal display device has a gate signal line (scanning line) and a source signal line (signal line) crossing each other, a large number of picture element electrodes formed in a matrix, and switching for controlling the picture element electrodes. It has an active matrix substrate provided with elements and the like. Then, the active matrix substrate and a counter substrate provided with a color filter, a counter electrode, and the like are bonded to each other so that their electrode forming surfaces face each other with a predetermined gap therebetween. Configuration.

[0004] The manufacturing process of this active matrix substrate is complicated and must go through many manufacturing processes. For this reason, defects such as mixing of foreign matter and short-circuiting between the pixel electrode and the scanning wiring or signal wiring are likely to occur, and it is very difficult to completely eliminate them. Therefore, detecting these defects at an early stage and making corrections as necessary is a very important task for improving the production yield.

Conventionally, the active matrix substrate and the opposing substrate are bonded to each other, a liquid crystal is injected between the cooling air plates to produce a liquid crystal panel, and then a lighting inspection is performed to detect the presence of a line defect or a point defect. A method has been proposed in which, if the defect can be corrected using a structure or the like, the defect can be corrected.

However, when an active matrix substrate and an opposing substrate are bonded to each other and a liquid crystal is injected between the two substrates to detect a defect after a liquid crystal panel is manufactured, the defect has a serious defect and the defect is corrected. Impossible liquid crystal panels must be discarded. Therefore, there is a problem that the production yield is reduced in the post-process and the manufacturing cost is increased.

Therefore, in recent years, it has been desired that a serious defect is detected in the state of the active matrix substrate before being bonded to the counter substrate, and that a correctable one such as a short-circuit defect is corrected in a previous step. It has become. Then, these defects can be detected in the substrate state by techniques such as image processing and resistance inspection, so that a process system can be created that corrects the defects in the substrate state and does not send defective products to the subsequent process. Is being done.

[0008]

By the way, in the above-mentioned liquid crystal display device, in order to improve the display quality, the picture element electrode is partially overlapped with a common signal wiring or an adjacent scanning wiring via an insulating film. There is known a configuration in which the superimposing unit is used as an auxiliary capacitance unit.

In the above structure, when a short-circuit defect occurs in the upper electrode (picture element electrode) and the lower electrode (common signal wiring or scanning wiring) of the auxiliary capacitor, the picture element electrode short-circuited with the common signal wiring has an opposing electrode. Since potentials of the same phase are applied, in the normally white mode, which is currently the mainstream, the spot always becomes a luminescent spot, and the display quality deteriorates. On the other hand, a negative constant potential is almost always applied to the pixel electrode that is short-circuited with the scanning wiring with respect to the counter electrode. I do.

When such a defect occurs, it is difficult to correct the defect after the fabrication of the liquid crystal panel as in the prior art because of the influence of the refractive index and transmittance of the glass substrate and the color filter forming portion, the influence on the liquid crystal alignment, and the like. The available lasers were limited and could not be corrected to normal picture elements.

SUMMARY OF THE INVENTION The present invention has been made to solve such problems of the prior art, and a short-circuit defect between an upper electrode and a lower electrode of an auxiliary capacitor in a state of an active matrix substrate before bonding to an opposing substrate. It is an object of the present invention to provide a method for repairing a defect of an active matrix substrate and a method for manufacturing a liquid crystal panel, which can correct the defect.

[0012]

According to the present invention, there is provided a method of repairing a defect in an active matrix substrate, wherein a plurality of scanning wirings and a plurality of signal wirings are provided so as to intersect with each other, and are provided in the vicinity of the intersection of the two wirings. A pixel electrode connected to both wirings via the switching element provided, and a plurality of common signal wirings are provided below the pixel electrode so as to partially overlap the pixel electrode via an insulating film. Is provided,
In an active matrix substrate in which an auxiliary capacitance portion in which a common signal wiring portion of a superimposed portion is a lower electrode and a pixel electrode portion of the superposed portion is an upper electrode, a short-circuit defect between the upper electrode and the lower electrode is reduced. A method for correcting a defect when it occurs, and irradiating the short-circuit defect with arbitrary light energy to remove an upper electrode around the short-circuit defect, thereby achieving the above object.

In the method of repairing defects of an active matrix substrate according to the present invention, a plurality of scanning wirings and a plurality of signal wirings are provided so as to intersect with each other, and a switching element provided near an intersection of the two wirings. A scanning electrode adjacent to the scanning electrode connected to the pixel electrode is partially overlapped with the pixel electrode via an insulating film. In the active matrix substrate in which the auxiliary capacitance portion is configured such that the scanning wiring portion of the portion is a lower electrode and the pixel electrode portion of the overlapping portion is an upper electrode, a short-circuit defect between the upper electrode and the lower electrode occurs. A method of correcting a defect in a case where the short-circuit defect is irradiated with arbitrary light energy to remove an upper electrode around the short-circuit defect, thereby achieving the above object.

Preferably, laser light is irradiated as the light energy.

In order to irradiate the light energy, it is preferable to use a laser which is an ultraviolet ray having an oscillation wavelength of 360 nm or less.

It is preferable to irradiate the fourth harmonic of a YAG laser as the light energy.

According to the method of manufacturing a liquid crystal panel of the present invention, after the defect is corrected by the method of correcting a defect of the active matrix substrate of the present invention, the active matrix substrate and the opposing substrate are bonded to inject liquid crystal between the two substrates. And the above object is achieved.

Hereinafter, the operation of the present invention will be described.

According to the present invention, a short-circuit defect between the lower electrode and the upper electrode in the auxiliary capacitance section composed of the common signal wiring or the scanning wiring (lower electrode), the insulating film and the pixel electrode (upper electrode). In the case where the short-circuit defect occurs, the upper electrode around the short-circuit defect is removed by irradiating light energy. Thereby, the short-circuit defect portion and the pixel electrode are isolated, and the short circuit between the lower electrode and the upper electrode is eliminated. Since defect repair is performed in the state of the active matrix substrate before bonding with the opposing substrate, the effect of the refractive index and transmittance of the glass substrate and color filter formation part, There is no influence on the orientation and the like, and the reliability of correction is improved. Defective products do not flow in the subsequent process, and there is no need to provide a redundant structure in advance for defect correction, so that the production yield is improved.

If a laser beam is used as the light energy, the laser beam can be processed in a non-contact manner and can be corrected quickly and easily.

If a short-wavelength laser having an oscillation wavelength of 360 nm or less, such as the fourth harmonic of a YAG laser, is used, it is possible to remove only the upper electrode around the short-circuit defect without affecting the underlying film. Can be.

[0022]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) In this embodiment, Cs on
An active matrix liquid crystal panel having a Common structure will be described.

FIG. 1 is a plan view of the liquid crystal panel of the first embodiment, and FIG. 2 is a cross-sectional view taken along the line II ′.

In this liquid crystal panel, in the active matrix substrate, a scanning wiring 2 and a signal wiring 4 are provided on a glass substrate 11 so as to intersect each other, and a TFT (thin film transistor) is provided as a switching element 6 near an intersection of both wirings. Have been. Pixel electrodes 5 are arranged in a matrix in a rectangular area separated by both wirings, and are connected to both wirings via switching elements 6.

Further, a common signal wiring 3 is provided between the adjacent scanning wirings 2 in a direction parallel to the scanning wirings 2, and a picture element electrode 5 partially overlaps thereover via an insulating film 7. .
The auxiliary capacitance unit 1 is composed of the common signal wiring 3, the insulating film 7, and the picture element electrode 5 of the superposed unit. Common signal wiring 3
Is made of a metal thin film having a thickness of about 300 nm to 500 nm, for example, Ta, Al, or the like.
A transparent conductive film of about 200 nm, for example, ITO (Indi
um Tin Oxide), and the insulating film 7 is formed of an insulating film (gate insulating film) having a thickness of about 300 nm to 500 nm, for example, SiN _x or SiO _x .

This active matrix substrate is bonded to a counter substrate provided with a counter electrode 9 on a glass substrate 10, and a liquid crystal layer 8 is sandwiched between both substrates.

In this liquid crystal panel, as shown in FIG. 2, when a pinhole 12 is generated in the insulating film 7 to short-circuit the common signal line 3 of the auxiliary capacitance section and the picture element electrode 5, the counter electrode 9 Since the same potential is applied to the common signal wiring 3 and the common signal wiring 3, no potential is applied between the pixel electrode 5 and the counter electrode 9 short-circuited to the common signal wiring 3. Therefore, the currently mainstream normally white mode liquid crystal is always displayed as a luminescent spot, which is a very conspicuous defect that degrades the display quality.

When such a short-circuit defect of the auxiliary capacitance portion 1 is corrected in the state of the liquid crystal panel as in the prior art, it is corrected due to the influence of the refractive index and transmittance of the glass substrate and the color filter forming portion, the influence on the liquid crystal alignment, and the like. Is difficult. In addition, there is a possibility that fragments or foreign matter scattered due to the correction remain in the liquid crystal layer and display defects occur.

Therefore, in the present embodiment, as shown in FIG. 3, defect correction is performed by irradiating the short-circuit defect portion 12 with light energy in the active matrix substrate state before bonding to the counter substrate. The defect can be detected by a technique such as image processing or resistance test.

Here, the irradiation of the fundamental wave of the YAG laser or the like may affect the lower layer film and cut the common signal wiring 3. Therefore, in this embodiment, the fourth harmonic (266 nm) of the YAG laser is used. Use a short wavelength laser such as

As a result, as shown in FIG. 4, the pixel electrode portion 13 around the short-circuit defect is removed to isolate the pinhole 12 from the pixel electrode 5, and the upper electrode and the lower electrode of the auxiliary capacitance portion are short-circuited. Can be eliminated.

Since the reduction of the auxiliary capacitance unit 1 affects the display state of the picture element, the area to be removed by irradiating light energy is, for example, in consideration of a design margin (for example, ± 5% or less). It is necessary to adjust it to within 2 μm □ to 5 μm □.

In the portion where the picture element electrode 5 is removed, light leakage occurs because no potential is applied between the picture element electrode 5 and the counter electrode, but the common signal wiring 3 is made of a light-shielding metal such as Al, Ti, Ta or the like. Since it is formed of a thin film, no problem occurs.

The liquid crystal panel of the present embodiment can be obtained by bonding the active matrix substrate having the defect corrected as described above and the opposing substrate and injecting liquid crystal into a gap between both substrates.

(Embodiment 2) In this embodiment, Cs on
An active matrix liquid crystal panel having a Gate structure will be described.

FIG. 5 is a plan view of the liquid crystal panel of the second embodiment, and FIG. 6 is a sectional view taken along the line II-II '.

In this liquid crystal panel, in the active matrix substrate, a scanning wiring 2 and a signal wiring 4 are provided on a glass substrate 11 so as to intersect with each other, and a TFT (thin film transistor) is provided as a switching element 6 near an intersection of both wirings. Have been. Pixel electrodes 5 are arranged in a matrix in a rectangular area separated by both wirings, and are connected to both wirings via switching elements 6.

Further, the pixel electrode 5 extends over the scanning line 2 adjacent to the scanning line 2 connected to the pixel electrode 5 and partially overlaps with the scanning line 2 via the insulating film 7. ing. The scanning line 2, the insulating film 7, and the picture element electrode 5 in the overlapping portion constitute the auxiliary capacitance unit 1. The scanning wiring 2 is a metal thin film having a thickness of about 300 nm to 500 nm, for example, Ta.
, Al or the like, and the pixel electrode 5 has a thickness of 100 nm to 20 nm.
The transparent conductive film of about 0 nm, made of, for example, ITO or the like, the insulating film 7 has a thickness 300nm~500nm about insulating film (gate insulating film) made of, for example, SiN _x or SiO _x or the like.

This active matrix substrate is bonded to a counter substrate provided with a counter electrode 9 on a glass substrate 10, and a liquid crystal layer 8 is sandwiched between both substrates.

In this liquid crystal panel, as shown in FIG. 6, when a pinhole 12 is generated in the insulating film 7 to short-circuit the scanning wiring 2 of the auxiliary capacitance portion and the picture element electrode 5, the scanning wiring 2 Since a constant negative potential is almost always applied to the counter electrode 9, a potential is almost always applied between the pixel electrode 5 short-circuited to the common signal wiring 3 and the counter electrode 9. Therefore, the currently mainstream normally white mode liquid crystal is almost always displayed as a black point, which is a defect that degrades the display quality.

When such a short-circuit defect of the auxiliary capacitance section 1 is corrected in the state of the liquid crystal panel as in the prior art, it is corrected due to the influence of the refractive index and transmittance of the glass substrate and the color filter forming section, the influence on the liquid crystal alignment, and the like. Is difficult. In addition, there is a possibility that fragments or foreign matter scattered due to the correction remain in the liquid crystal layer and display defects occur.

Therefore, in the present embodiment, as shown in FIG. 7, defect repair is performed by irradiating the short-circuit defect portion 12 with light energy in the state of the active matrix substrate before bonding to the counter substrate. The defect can be detected by a technique such as image processing or resistance test.

Here, the irradiation of the fundamental wave of the YAG laser or the like may affect the lower layer film and cut the scanning wiring 2. Therefore, in this embodiment, the fourth harmonic (266 nm) of the YAG laser or the like is used. Using a short wavelength laser.

As a result, as shown in FIG. 8, the pixel electrode portion 13 around the short-circuit defect portion is removed to isolate the pinhole 12 from the pixel electrode 5, and the upper electrode and the lower electrode of the auxiliary capacitance portion are short-circuited. Can be eliminated.

Since the reduction of the auxiliary capacitance unit 1 affects the display state of the picture element, the area to be removed by irradiating light energy is, for example, in consideration of a design margin (eg, ± 5% or less). It is necessary to adjust it to within 2 μm □ to 5 μm □.

In the portion where the picture element electrode 5 is removed, light leakage occurs because no potential is applied between the pixel electrode 5 and the counter electrode, but the scanning wiring 2 is made of a light-shielding metal thin film such as Al, Ti or Ta. Therefore, no problem occurs.

The liquid crystal panel of the present embodiment can be obtained by bonding the active matrix substrate having the defect corrected as described above and the opposing substrate and injecting liquid crystal into a gap between both substrates.

In the first and second embodiments, when the upper electrode around the short-circuit defect is removed to isolate the short-circuit defect from the pixel electrode, (1) the storage capacitor 1 is reduced. (2) If light leakage does not occur, it is also possible to remove the short-circuited portion and remove only the surrounding portion.

Although the fourth harmonic of the YAG laser is used as the light energy in the first and second embodiments, other lasers may be used if conditions can be set so as not to affect the underlying film. Is also good.

Further, a method utilizing light energy other than laser light, such as radiation or plasma, is also possible.

[0052]

As described above in detail, according to the present invention, in the state of the active matrix substrate before the liquid crystal is injected by being bonded to the counter substrate, the auxiliary capacitance portion which has been difficult to correct in the prior art is obtained. The short-circuit defect between the upper electrode and the lower electrode can be eliminated and corrected to a normal pixel. Therefore, it is possible to minimize the manufacturing loss by preventing the correction failure from being transmitted to the post-process, thereby improving the manufacturing yield and greatly reducing the cost. Furthermore, since the defect is repaired in the state of the active matrix substrate, cleaning after the repair is possible, and there is no foreign matter remaining in the liquid crystal layer, so that the reliability of the repair can be improved.

[Brief description of the drawings]

FIG. 1 is a plan view illustrating a schematic configuration of a picture element portion in a liquid crystal panel according to a first embodiment.

FIG. 2 is a cross-sectional view for explaining a short-circuit defect of an auxiliary capacitance section in the liquid crystal panel of the first embodiment.

FIG. 3 is a cross-sectional view illustrating a method for correcting a defect of the active matrix substrate according to the first embodiment.

FIG. 4 is a cross-sectional view for explaining a defect repair method for the active matrix substrate according to the first embodiment.

FIG. 5 is a plan view illustrating a schematic configuration of a picture element portion in a liquid crystal panel according to a second embodiment.

FIG. 6 is a cross-sectional view for explaining a short-circuit defect of an auxiliary capacitance section in the liquid crystal panel of the second embodiment.

FIG. 7 is a cross-sectional view illustrating a method for correcting a defect of an active matrix substrate according to a second embodiment.

FIG. 8 is a cross-sectional view illustrating a method for correcting a defect of an active matrix substrate according to the second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Auxiliary capacitance part 2 Scanning wiring 3 Common signal wiring 4 Signal wiring 5 Pixel electrode 6 Switching element 7 Insulating film (Gate insulating film) 8 Liquid crystal layer 9 Counter electrode 10, 11 Glass substrate 12 Short circuit defect part (pinhole) 13 Laser Pixel electrode part removed by irradiation

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (reference) AA14 AA17 BB12 CC09 EE33 EE41 HH12 KK05 KK09 KK10

Claims (6)

[Claims] A picture element electrode provided with a plurality of scanning lines and a plurality of signal lines intersecting each other, and connected to both lines via a switching element provided near an intersection of the two lines. Further, a plurality of common signal lines are provided below the pixel electrode so as to partially overlap the pixel electrode via an insulating film via an insulating film, and the common signal wiring portion of the overlapping portion is defined as a lower electrode. A method of correcting a short-circuit defect between the upper electrode and the lower electrode in an active matrix substrate in which an auxiliary capacitance portion having the pixel electrode portion of the overlapping portion as an upper electrode is formed. A defect repair method for an active matrix substrate, wherein the short-circuit defect is irradiated with arbitrary light energy to remove an upper electrode around the short-circuit defect. 2. A picture element electrode in which a plurality of scanning lines and a plurality of signal lines are provided so as to intersect with each other, and which are connected to both lines via a switching element provided near an intersection of the two lines. Is provided, further, the scanning wiring adjacent to the scanning wiring connected to the picture element electrode and the picture element electrode are partially overlapped via an insulating film, and the scanning wiring part of the overlapping portion is a lower electrode, In an active matrix substrate in which an auxiliary capacitance portion having the picture element electrode portion of the superposed portion as an upper electrode is formed, if a short-circuit defect occurs between the upper electrode and the lower electrode, the defect is corrected. And irradiating the short-circuit defect with arbitrary light energy to remove an upper electrode around the short-circuit defect. 3. The method according to claim 1, wherein a laser beam is irradiated as the light energy. 4. The method according to claim 3, wherein a laser having an oscillation wavelength of 360 nm or less is used to irradiate the light energy. 5. The method according to claim 4, wherein a fourth harmonic of a YAG laser is applied as the light energy. 6. An active matrix substrate and a counter substrate are attached to each other by correcting a defect by the defect repair method for an active matrix substrate according to claim 1. A method for manufacturing a liquid crystal panel including a step of injecting a liquid crystal.