JPH095786A - Tft array substrate as well as liquid crystal display device formed by using the tft array substrate and production of tft array substrate - Google Patents

Abstract

PURPOSE: To provide a TFT array with which the sure repair of a dot defect is possible and a process for producing this array. CONSTITUTION: This TFT array substrate has a dot defect repair pattern 11 which is simultaneously formed of the same material as the material of storage capacitance electrodes 2 and overlaps on adjacent two pixels and an island 12 which is formed on this dot defect repair pattern 11 via a storage capacitance dielectric film 3. The transistor part of the pixel recognized to be the spot defect is cut at a C-C line part by a laser beam and thereafter, the D part on the pixel electrode 5 and the D part on the pixel electrode 5 of the adjacent pixel are irradiated with the laser beam, by which the pixel electrodes of the adjacent pixels are shorted via the dot defect repair pattern 11. Two metallic films via the insulating film, i.e., the dot defect repair pattern 11 and the island 12 are connected by the laser and, therefore, the repair is easily and surely executed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a TFT array substrate and a method of manufacturing the same, and in particular, a method of repairing a point defect which is one of the factors that reduce the yield.

[0002]

[Prior art]

FIG. 9 is a partially enlarged view of a TFT array used in a conventional liquid crystal display device, and FIG. 10 is a sectional view taken along line AA in FIG. In the figure, 1 is a glass substrate, 2 is a storage capacitor electrode, 3 is a storage capacitor dielectric, 4 is a gate wiring also serving as a gate electrode, 5 is a pixel electrode made of a transparent conductive film,
6 is a gate insulating film, 7 is a semiconductor layer, 8 is an ohmic contact layer, 9 is a source wiring also serving as a source electrode, 1
Reference numeral 0 denotes a drain electrode, respectively.

Next, the manufacturing process and structure of a conventional TFT array will be described. First, C on the washed glass substrate 1
A metal thin film of r, Ta, Ti or the like is formed by a method such as a sputtering method, and this is patterned by a method such as a photoetching method to form the storage capacitor electrode 2. Next, a film of SiN, SiO ₂ or the like to be the dielectric film 3 of the storage capacitor is formed by a plasma CVD (chemical vapor deposition) method or the like, and a gate electrode and a gate wiring 4 to be formed later are contacted. A contact hole or the like is patterned. Then C
A metal thin film of r, Ta, Ti or the like is formed by a method such as a sputtering method, and this is patterned by a method such as a photoetching method to form the gate electrode and the gate wiring 4. Further, a transparent conductive film such as ITO (Indium Tin Oxide) is formed by a method such as sputtering, and this is pattern-formed by a method such as a photo etching method.
To form

Next, SiN or Si to be the gate insulating film 6 is formed.
An insulating film such as O ₂ or ia-Si that becomes the semiconductor layer 7, or p
Poly-Si or the like, and n-a-Si or the like to be the ohmic contact layer 8 are formed by the plasma CVD method or the like. Next, the na-Si and i-a-Si are patterned into an island shape or a line shape by a method such as a photoetching method. Next, a pattern is formed by a method such as a photo etching method to form a contact hole on the pixel electrode 5. Further, a metal thin film of Al, Cr or the like is formed by a sputtering method or the like, and this is pattern-formed by a photo etching method or the like to form the source electrode, the source wiring 9 and the drain electrode 10, and then n between the source and the drain is formed. -A-
Etch off Si. Finally, a protective film made of SiN or the like is formed if necessary.

In the TFT array configured as described above, a pixel that does not operate normally, that is, a point defect, is generated due to a short circuit between the gate electrode 4 and the drain electrode 10 due to foreign matter or insufficient ohmic contact. Occurs with a probability of a few ppm. As a method for repairing this defect, Japanese Patent Application Laid-Open No. 2-284120 and Japanese Patent Application Laid-Open No. 5-6641 are known.
As shown in FIG. 5, there is a method in which a pattern for connecting drive electrodes adjacent to each other is formed at the same time as a storage capacitor, and this is melted by laser irradiation to connect a defective pixel electrode to an adjacent pixel electrode. is there.

[0007]

As described above, the conventional TFT array has a problem that the yield is reduced due to the generation of point defects. Further, the conventional point defect repairing method has a pattern for repairing the point defect. However, when the pixel electrode adjacent to this pattern is connected by laser irradiation, the pixel electrode is irradiated by irradiation from the pixel electrode side. Since it is transparent, it passes through the laser, and there is a problem that it is difficult to make a sufficient connection.

The present invention has been made to solve the above problems, and provides a TFT array having a structure capable of easily and surely repairing a point defect and a manufacturing method thereof.

[0009]

SUMMARY OF THE INVENTION A TFT according to the present invention
The array substrate forms a semiconductor element together with a gate wiring that also serves as a gate electrode made of a metal thin film formed on a transparent insulating substrate, a semiconductor layer provided on the gate wiring via a gate insulating film, and this semiconductor layer. A source wiring and a drain electrode which also serve as a source electrode, a pixel electrode made of a transparent conductive film provided in the vicinity of the semiconductor element, a storage capacitor electrode made of a metal thin film formed on the transparent insulating substrate, on this storage capacitor electrode A storage capacitor dielectric film, a first metal pattern made of the same metal material as that of the storage capacitor electrode and extending over two adjacent pixels, and the storage capacitor on the first metal pattern. A second metal pattern arranged via an insulating film such as a dielectric film is provided, and the first metal pattern and the second metal pattern are formed by laser irradiation. The connecting between the two adjacent pixel electrodes by connecting by melting, in which to perform the repair of pixel defects. Also, the storage capacitor electrode and the first
The metal pattern of is made of a metal such as Cr, Ta or Ti. The second metal pattern is made of Cr, T
It is made of a metal such as a or Ti. Also, the second
The metal pattern of is made of the same metal material as the gate wiring. Furthermore, the second metal pattern is formed in contact with the top or bottom of the pixel electrode.

Further, in the method of manufacturing a TFT array substrate according to the present invention, a metal thin film of Cr, Ta, Ti or the like is formed on a transparent insulating substrate by a sputtering method or the like, and is patterned by a method such as a photo etching method. A step of forming and forming a first metal pattern across the storage capacitor electrode and two adjacent pixels, and forming a metal thin film of Cr, Ta, Ti or the like by a sputtering method, etc. Forming a second metal pattern on the gate electrode / wiring and the first metal pattern via at least the storage capacitor dielectric film.
When a pixel defect is recognized, the signal level of the pixel is separated by laser irradiation, and the first metal pattern and the second metal pattern are separated.
And melting the metal pattern and connecting the two adjacent pixel electrodes to repair the pixel defect.

[0011]

In the TFT array substrate according to the present invention, when a pixel defect is recognized, the signal level of the pixel is separated by laser irradiation, and the defective pixel and the first metal pattern and the second metal pattern of the pixel adjacent thereto are separated. By melting the respective metal patterns and connecting the first metal pattern and the pixel electrode, two adjacent pixel electrodes are connected, and the defective pixel and the pixel electrode of the pixel adjacent thereto have the same potential, Since the display is made, it becomes difficult to visually recognize the defect, and the pixel defect can be easily and surely repaired. Furthermore, since the second metal pattern is formed in contact with the upper or lower part of the pixel electrode, the first metal pattern and the second metal pattern are melted to form the first metal pattern and the pixel electrode. The connection can be surely made, and it is particularly effective for laser irradiation from the pixel electrode side.

In the method of manufacturing a TFT array substrate according to the present invention, the first metal pattern and the second metal pattern are simultaneously formed of the same metal material and the storage capacitor electrode, respectively. Only the mask needs to be changed in the same number of steps as in (3), and the manufacturing can be performed easily without increasing the cost.

[0013]

【Example】

Embodiment 1 FIG. Example 1 of the present invention will be described with reference to the drawings. FIG. 1 is a partial plan view of a TFT array used in the display device of the present invention, FIG. 2 is a sectional view taken along line AA of FIG. 1, and FIG. 3 is B of FIG.
It is a -B sectional view. In the figure, 11 is the storage capacitor electrode 2
Is a first metal pattern simultaneously formed with the same material as the point defect repair pattern, and 12 is an island which is a second metal pattern simultaneously formed with the same material as the gate electrode and the gate wiring 4, and an island 12 Are formed below and in contact with the pixel electrode 5. Also, C-C in the figure
And D are laser irradiation points at the time of repairing point defects. The same parts as those of the conventional example are designated by the same reference numerals, and the description thereof will be omitted.

Next, a method of manufacturing the TFT array in this embodiment will be described. First, the washed glass substrate 1
Then, a metal thin film of Cr, Ta, Ti or the like is formed by a method such as a sputtering method, and this is patterned by a method such as a photoetching method to form the storage capacitor electrode 2 and the point defect repair pattern 11. Next, a film of SiN, SiO ₂ or the like to be the dielectric film 3 of the storage capacitor is formed by a plasma CVD (chemical vapor deposition) method or the like, and a gate electrode and a gate wiring 4 to be formed later are contacted. A contact hole or the like is patterned. Next, a refractory metal thin film of Cr, Ta, Ti or the like is formed to a film thickness of about 300 nm by a method such as a sputtering method, and this is pattern-formed by a method such as a photoetching method to form the gate electrode / wiring 4 and point defects. The island 12 is formed at the connection portion with the repair pattern 11. That is, the island 12 is formed on the point defect repair pattern 11 via the dielectric 3 of the storage capacitor at the laser irradiation position D when repairing the point defect.

Further, ITO (indium tin oxide)
A transparent conductive film such as a film having a thickness of 100 is formed by a method such as sputtering.
A film having a thickness of about nm is formed, and this is patterned by a method such as a photoetching method to form the pixel electrode 5. Next, an insulating film such as SiN or SiO ₂ to be the gate insulating film 6 is formed to a thickness of 30.
About 0 nm, ia-Si that becomes the semiconductor layer 7 and pol
A film thickness of about 200 nm of y-Si or the like and about 50 nm of na-Si or the like to be the ohmic contact layer 8 is formed by a plasma CVD (chemical vapor deposition) method or the like. Next, the na-Si and i-a-Si are patterned into a line shape or an island shape by a method such as a photoetching method. Next, a pattern is formed by a method such as a photo etching method to form a contact hole on the pixel electrode 5. Next, a metal thin film of Al, Cr or the like is formed to a film thickness of about 400 nm by a sputtering method or the like, and this is patterned by a photo etching method or the like to form the source electrode / wiring 9 and the drain electrode 10, and then the source / drain. N between
Etch off a-Si. Finally, if necessary, S
A protective film is formed with iN or the like.

In the TFT array manufactured as described above and the liquid crystal display device using the TFT array, for the pixel recognized as a point defect, the transistor portion of the pixel is irradiated with laser light and the CC line portion shown in FIG. Then, the D portion on the pixel electrode 5 and the D portion on the pixel electrode 5 of the adjacent pixel are irradiated with laser light to short-circuit the pixel electrodes of the adjacent pixels via the point defect repair pattern 11. In this case, since the two metal films, that is, the point defect repair pattern 11 and the island 12 are connected by the laser via the dielectric 3 of the storage capacitor, the repair can be performed easily and surely. In particular, it is effective for laser irradiation from the pixel electrode 5 side. Although the left and right pixel electrodes are connected in this embodiment, the upper and lower pixel electrodes can be connected.

According to this embodiment, a pixel recognized as a point defect is short-circuited with an adjacent pixel by using the point defect repair pattern 11, so that the pixel electrodes adjacent to each other have the same potential and the same display. Therefore, it becomes difficult to visually recognize as a point defect, and the yield of the TFT array is improved. Further, since only the pattern is changed by the manufacturing method similar to the conventional method, there is an advantage that the cost is not increased without increasing the number of steps. Further, according to the present invention, not to mention the point defect found in the TFT array stage, a liquid crystal display device in which liquid crystal is sandwiched between this TFT array substrate and a counter electrode substrate having a transparent electrode, a color filter and the like. After that, that is, even when the laser light is incident from the pixel electrode side, the repair can be performed easily and surely.

Embodiment 2 FIG. FIG. 4 is a partial cross-sectional view showing a TFT array used in a display device which is Embodiment 2 of the present invention. In this embodiment, the gate electrode / wiring 4 and the pixel electrode 5 are
The structure is the same as that of the first embodiment except that the order of the manufacturing steps is changed. That is, the pixel electrode 5 is formed on the point defect repair pattern 11 via the dielectric 3 of the storage capacitor, and the island 12 is formed thereon. As described above, the island 12 may be above or below the pixel electrode 5, and it is possible to easily repair the point defect by using the point defect repair pattern 11 in any structure. The same effect as in Example 1 can be obtained.

Embodiment 3 FIG. A third embodiment of the present invention will be described with reference to the drawings. 5 is a partial plan view of a TFT array used in the liquid crystal display device of the present invention, FIG. 6 is a sectional view taken along line AA of FIG. 5, and FIG. 7 is a sectional view taken along line BB of FIG. In the figure, 1
3 is an etching stopper film.

A method of manufacturing the TFT array in this embodiment will be described. First, C on the washed glass substrate 1
A metal thin film of r, Ta, Ti or the like is formed by a method such as a sputtering method, and this is patterned by a method such as a photoetching method to form the storage capacitor electrode 2 and the point defect repair pattern 11. Next, a film such as SiN or SiO ₂ which will be the dielectric film 3 of the storage capacitor is formed by a plasma CVD (chemical vapor deposition) method or the like, and a contact for contacting a gate electrode / wiring to be formed later is formed. Pattern holes and the like. Next, a refractory metal thin film of Cr, Ta, Ti or the like is formed to a film thickness of about 300 nm by a method such as a sputtering method, and this is formed into a pattern by a method such as a photoetching method. Defect repair pattern 1
The island 12 is formed at the connection portion with 1. That is, the island 12 is formed on the point defect repair pattern 11 via the dielectric 3 of the storage capacitor at the laser irradiation position when repairing the point defect.

Further, ITO (indium tin oxide)
A transparent conductive film such as a film having a thickness of 100 is formed by a method such as sputtering.
A film having a thickness of about nm is formed. This film thickness is 150 nm at maximum in order to obtain the brightness required for a liquid crystal display device.
This is patterned by a method such as photo etching,
The pixel electrode 5 is formed. Next, S that becomes the gate insulating film 6
Insulating films such as iN and SiO ₂ having a film thickness of about 300 nm, ia-Si forming the semiconductor layer 7 and poly-Si having a film thickness of about 100 nm, and insulating films such as SiN and SiO ₂ forming the etching stopper film 13. The film thickness is about 200 nm,
A film is formed by a plasma CVD method or the like. Next, the etching stopper film 13 is patterned by a method such as a photo etching method. Then, n- which becomes the ohmic contact layer 8 is formed.
A film of a-Si or the like having a thickness of about 50 nm is formed by a plasma CVD method or the like, and a pattern is formed by a method such as a photo-etching method or the like to form a contact hole on the pixel electrode 5. Next, A
l, a metal thin film such as Cr having a film thickness of 40 by a sputtering method or the like.
A film having a thickness of about 0 nm is formed, and a pattern is formed by a photoetching method or the like to form the source electrode / wiring 9 and the drain electrode 1.
Form 0. Next, na between the source and the drain
-Si and unnecessary n-a-Si and i-a in the pixel section
Etch off Si. Finally, if necessary, SiN
Etc. to form a protective film.

In the TFT array produced as described above and the liquid crystal display device using the TFT array, for the pixel recognized as a point defect, the transistor portion of the pixel is irradiated with laser light to show the CC line portion shown in FIG. Then, the D portion on the pixel electrode 5 and the D portion on the pixel electrode 5 of the adjacent pixel are respectively irradiated with laser light, and the point defect repair pattern 11 is formed.
The pixel electrodes of the adjacent pixels are short-circuited via. Also in the TFT array having the above structure, the same effects as those of the first and second embodiments can be obtained.

Embodiment 4 FIG. FIG. 8 is a partial cross-sectional view showing a TFT array used in a liquid crystal display device which is Embodiment 4 of the present invention. This embodiment has the same structure as that of the third embodiment except that the order of manufacturing steps of the gate electrode 4 and the pixel electrode 5 is changed. That is, on the point defect repair pattern 11,
The pixel electrode 5 is formed via the dielectric film 3 of the storage capacitor,
The island 12 is formed on it. Even with such a structure, the point defect can be easily repaired by using the point defect repair pattern 11, and the same effect as that of the first to third embodiments can be obtained. In addition, the TFT shown in the above embodiment
The structures of the arrays are only examples and the invention is not limited to these structures.

[0024]

As described above, according to the present invention, a first metal pattern that overlaps two adjacent pixels by laser irradiation, and a storage capacitor dielectric film or the like is formed on the first metal pattern. By melting the second metal pattern formed through the insulating film, a TFT array substrate in which pixel defects can be easily and reliably repaired and a liquid crystal display device using the TFT array substrate are obtained, and the yield is improved. Has the effect of

According to the manufacturing method of the present invention,
Since the first metal pattern and the second metal pattern are simultaneously formed with the same metal material as the storage capacitor electrode and the second metal pattern, respectively, only the mask needs to be changed in the same number of steps as the conventional steps, which results in high cost. It can be easily manufactured.

[Brief description of drawings]

FIG. 1 is a partial plan view showing a TFT array used in a liquid crystal display device according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is a sectional view taken along line BB of FIG.

FIG. 4 is a partial sectional view showing a TFT array used in a liquid crystal display device according to a second embodiment of the present invention.

FIG. 5 is a partial plan view showing a TFT array used in a liquid crystal display device according to a third embodiment of the present invention.

6 is a cross-sectional view taken along the line AA of FIG.

7 is a sectional view taken along line BB of FIG.

FIG. 8 is a partial cross-sectional view showing a TFT array used in a liquid crystal display device which is a fourth embodiment of the present invention.

FIG. 9 is a partial plan view showing a TFT array used in a conventional liquid crystal display device.

10 is a cross-sectional view taken along the line AA of FIG.

[Explanation of symbols]

1 glass substrate, 2 storage capacitor electrode, 3 storage capacitor dielectric film, 4 gate electrode / wiring, 5 pixel electrode, 6 gate insulating film, 7 semiconductor layer, 8 ohmic contact layer, 9 source electrode / wiring, 10 drain electrode , 11
Point defect repair pattern, 12 islands.

Claims (7)

[Claims] 1. A gate wiring formed on a transparent insulating substrate and also serving as a gate electrode made of a metal thin film, a semiconductor layer provided on the gate wiring via a gate insulating film, and a semiconductor element together with this semiconductor layer. A source wiring and a drain electrode which also serve as a source electrode, a pixel electrode made of a transparent conductive film provided in the vicinity of the semiconductor element, a storage capacitor electrode made of a metal thin film formed on the transparent insulating substrate, and this storage capacitor electrode. A storage capacitor dielectric film provided above, a first metal pattern made of the same metal material as that of the storage capacitor electrode and arranged over two adjacent pixels, and the storage on the first metal pattern. A second metal pattern arranged via an insulating film such as a capacitive dielectric film is provided, and the first metal pattern and the second metal pattern are formed by laser irradiation. A TFT array substrate, characterized in that the two pixel electrodes adjacent to each other are melted and connected to each other to repair pixel defects. 2. The TFT array substrate according to claim 1, wherein the storage capacitor electrode and the first metal pattern are made of a metal such as Cr, Ta or Ti. 3. The TFT array substrate according to claim 1, wherein the second metal pattern is made of a metal such as Cr, Ta or Ti. 4. The TFT array substrate according to claim 1, wherein the second metal pattern is made of the same metal material as the gate wiring. 5. The TFT array substrate according to claim 1, wherein the second metal pattern is formed in contact with above or below the pixel electrode. 6. A liquid crystal is arranged between the TFT array substrate according to any one of claims 1 to 5 and a counter electrode substrate having a transparent electrode and a color filter or the like. Liquid crystal display device. 7. Cr, Ta or Ti on a transparent insulating substrate
Forming a first metal pattern across the storage capacitor electrode and two adjacent pixels by forming a metal thin film such as a film by a sputtering method or the like and forming a pattern by a method such as a photoetching method, SiN , SiO ₂ etc. are formed by plasma CVD (Chemical Vapor Deposition) method etc., this is patterned to form a storage capacitor dielectric film, metal thin film of Cr, Ta or Ti etc. is sputtered etc. And forming a pattern by a method such as a photoetching method, and forming a second metal pattern on the gate electrode / wiring and the first metal pattern through at least the storage capacitor dielectric film. A step of forming a pixel electrode by patterning a transparent conductive film by a method such as sputtering, a gate insulating film, a semiconductor layer and an ohmic contact layer A step of sequentially forming a film by plasma CVD or the like and forming a pattern thereof, a step of forming a metal thin film of Al, Cr or the like by a sputtering method, and forming a source electrode / wiring and a drain electrode by pattern formation, a pixel defect If the signal is detected, the signal circuit of the pixel is cut off by laser irradiation, the first metal pattern and the second metal pattern are melted, and two adjacent pixel electrodes are connected to each other to form a pixel. A method of manufacturing a TFT array substrate, comprising the step of repairing defects.