JP2001332742A - Thin film transistor substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance an insulation breakdown strength between polymerization parts of a data signal line and an auxiliary capacity electrode in a thin film transistor substrate of an active matrix type liquid crystal display panel. SOLUTION: There is consecutively provided an insulation breakdown strength insulation film 14 composed of a film for forming a channel protection film 10 between intersection parts of a sweep signal line 2 and a data signal line 3 and between polymerization parts of the data signal line 3 and an auxiliary capacity electrode 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a thin film transistor substrate.

[0002]

2. Description of the Related Art There is an active matrix type liquid crystal display panel in which a thin film transistor substrate and a counter substrate are bonded to each other and liquid crystal is sealed between them. FIG. 5 shows a partial transmission plan view of an example of a thin film transistor substrate in such a conventional liquid crystal display panel, and FIG.
FIG. 3 shows a cross-sectional view along the line. This thin film transistor substrate includes a glass substrate 1. A scanning signal line 2 and a data signal line 3 are provided in a matrix on the upper surface side of the glass substrate 1, and a thin film transistor 4, a pixel electrode 5, and an auxiliary capacitance electrode 6 are provided near each intersection thereof.

That is, a scanning signal line 2 including a gate electrode 7 is provided at a predetermined location on the upper surface of the glass substrate 1, and an auxiliary capacitance electrode 6, which will be described in detail later, is provided at another predetermined location. . A gate insulating film 8 made of silicon nitride or the like is provided on the entire upper surface. A semiconductor thin film 9 made of intrinsic amorphous silicon is provided at a predetermined position on the gate electrode 7 on the gate electrode 7. At a predetermined position on the upper surface of the semiconductor thin film 9, a channel protective film 10 made of silicon nitride or the like is provided. Ohmic contact layers 11 and 12 made of n-type amorphous silicon are provided on both sides of the upper surface of the channel protective film 10 and on the upper surface of the semiconductor thin film 9 on both sides thereof.

A data signal line 3 including a drain electrode 13 is provided at a predetermined position on the upper surface of one ohmic contact layer 11 and on the upper surface of the gate insulating film 8.
In this case, the data signal line 3 is composed of an intrinsic amorphous silicon film 3a, an n-type amorphous silicon film 3b, and a metal film 3 made of aluminum or the like for forming the drain electrode 13.
c has a three-layer structure. The intrinsic amorphous silicon film 3a is formed simultaneously with the formation of the semiconductor thin film 9, and is formed along the data signal line 3 with the same material and the same thickness as the semiconductor thin film 9.

At the intersection of the data signal line 3 and the scanning signal line 2, a channel protective film for forming a channel protective film 10 between the intrinsic amorphous silicon film 3a and the n-type amorphous silicon film 3b. An insulating film 14 for improving withstand voltage made of a forming film is provided. That is, the insulating film 14 for improving the withstand voltage is formed by depositing an insulating film made of silicon nitride or the like on the intrinsic amorphous silicon film 3a and patterning the same to form the channel protective film 10.
With the same material and the same thickness as the channel protective film 10.

A source electrode 15 is provided on the upper surface of the other ohmic contact layer 12. An overcoat film 16 made of silicon nitride or the like is provided on the entire upper surface. A pixel electrode 5 made of ITO is provided at a predetermined position on the upper surface of the overcoat film 16. The pixel electrode 5 is connected to the source electrode 15 via a contact hole 17 provided in the overcoat film 16.

The auxiliary capacitance electrode 6 extends in the direction in which the data signal lines 3 are arranged at a position where the storage capacitance electrode 6 overlaps with the data signal line 3 at a position overlapping the straight line portion 6 a arranged in parallel with the scanning signal line 2. And an extension 6b. In this case, the width of the extension portion 6b is determined by the right side portion and the right side pixel portion of the left side pixel electrode 5 among the pixel electrodes 5 arranged on the left and right sides of the data signal line 3 on the left side and right side portion of the extension portion 6b The width overlaps with the left side of the electrode 5.

The substantially U-shaped portion consisting of two adjacent extending portions 6b and a straight portion 6a therebetween is formed by a pixel electrode 5
Are overlapped with predetermined three sides, and the overlapped portion forms an auxiliary capacitance portion. In this case, the three sides inside the substantially U-shaped portion form part of the edge of the pixel opening, thereby increasing the aperture ratio.

[0009]

By the way, in the above-mentioned conventional thin film transistor substrate, an insulating film 14 for improving the withstand voltage is provided in addition to the gate insulating film 8 between the intersections of the scanning signal lines 2 and the data signal lines 3. Therefore, the withstand voltage between the intersections of the scanning signal lines 2 and the data signal lines 3 can be improved. On the other hand, the potential difference between the data signal line 3 and the auxiliary capacitance electrode 6 is relatively small. Therefore, even if only the gate insulating film 8 is provided between the overlapping portions of the data signal line 3 and the auxiliary capacitance electrode 6, the dielectric strength can be reduced. There is not much problem. However, even though there is not much problem,
Since it is not perfect, the reliability of the withstand voltage cannot be said to be sufficient. SUMMARY OF THE INVENTION It is an object of the present invention to improve the withstand voltage between overlapping portions of a data signal line and an auxiliary capacitance electrode.

[0010]

According to a first aspect of the present invention, there is provided a thin film transistor substrate provided with a thin film transistor, a pixel electrode, and an auxiliary capacitance electrode near each intersection of a scanning signal line and a data signal line provided in a matrix. A gate insulating film provided between the scanning signal line and the auxiliary capacitance electrode and the data signal line;
An insulating film for improving withstand voltage is continuously provided between intersections of the scanning signal lines and the data signal lines and between overlapping portions of the data signal lines and the auxiliary capacitance electrodes. According to a second aspect of the present invention, in the first aspect of the present invention, the insulating film for improving withstand voltage is formed on the gate insulating film. According to a third aspect of the present invention, in the first aspect of the invention, a semiconductor thin film is formed along the data signal line on the gate insulating film;
The insulating film for improving the withstand voltage is formed on the semiconductor thin film. The invention according to claim 4 is the invention according to claims 1 to 3.
In the invention described in any one of the above (1) to (4), the insulating film for improving withstand voltage is provided continuously over substantially the entire area in the arrangement direction of the data signal lines. According to a fifth aspect of the present invention, in the first aspect of the present invention, the insulating film for improving withstand voltage is the same as a channel protective film forming film for forming a channel protective film of the thin film transistor. Formed of the above material. The invention according to claim 6 is the invention according to any one of claims 1 to 3,
A side portion of the pixel electrode is overlapped with the insulating film for improving withstand voltage. According to the first aspect of the present invention, since the insulating film for improving the withstand voltage is provided between the overlapping portion of the data signal line and the auxiliary capacitance electrode, the insulating film is provided between the overlapping portion of the data signal line and the auxiliary capacitance electrode. Can be improved in withstand voltage. In this case, since the insulating film for improving the withstand voltage is continuously provided between the intersections of the scanning signal lines and the data signal lines and between the overlapping portions of the data signal lines and the auxiliary capacitance electrodes, the aperture ratio does not decrease. That's why.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a transparent plan view of a main part of a thin film transistor substrate according to an embodiment of the present invention.
FIG. 2 is a sectional view taken along the line XX.
In these figures, the same reference numerals are given to the same parts as those in FIGS. 5 and 6, and the description thereof will be appropriately omitted.

In the thin film transistor substrate of this embodiment, the film for forming the channel protective film 10 is provided between the intersections of the scanning signal lines 2 and the data signal lines 3 and between the overlapping portions of the data signal lines 3 and the auxiliary capacitance electrodes 6. The insulating film 14 for improving the withstand voltage is continuously provided. However,
Also in this case, the data signal line 3 has a three-layer structure of an intrinsic amorphous silicon film 3a, an n-type amorphous silicon film 3b, and a metal film 3c made of aluminum or the like for forming the drain electrode 13. Therefore, the insulating film 14 for improving the withstand voltage is made of the intrinsic amorphous silicon film 3a and n
It is provided between the amorphous silicon film 3b. Also in the embodiment of the present invention, the insulation withstand voltage improving insulating film 14 is formed by depositing an insulating film made of silicon nitride or the like on the intrinsic amorphous silicon film 3a and patterning the same together with the channel protective film 10;
The same material and the same thickness as the channel protective film 10 are formed.

As described above, in the thin film transistor substrate of this embodiment, since the insulating film 14 for improving the withstand voltage is provided between the overlapping portions of the data signal lines 3 and the auxiliary capacitance electrodes 6, the data signal lines 3 and the auxiliary capacitances are provided. The withstand voltage between the overlapping portion with the electrode 6 can be improved. In addition, since the insulating film 14 for improving the withstand voltage is continuously provided between the intersections of the scanning signal lines 2 and the data signal lines 3 and between the overlapping portions of the data signal lines 3 and the auxiliary capacitance electrodes 6, As described, the aperture ratio can be prevented from lowering.

For example, as a comparative example, as shown in FIG. 3, an insulating film 14A for improving the withstand voltage is provided between the intersections of the scanning signal line 2 and the data signal line 3, and the data signal line 3 and the auxiliary capacitance electrode 6 are provided. And a structure in which an insulating film 14B for improving withstand voltage is provided between the overlapping portions. That is, the insulating film for improving the withstand voltage is separated into one indicated by reference numeral 14A and one indicated by reference numeral 14B. Then, a minimum separation gap D is formed between the insulating films 14A and 14B for improving the withstand voltage. Then, in order to provide the insulation withstand voltage improving insulating film 14B between the overlapping portion of the data signal line 3 and the auxiliary capacitance electrode 6,
The auxiliary capacitance electrode 6 below the data signal line 3 is arranged to be separated from the scanning signal line 2 by an amount corresponding to the gap D. As a result, a predetermined portion of the linear portion 6a of the auxiliary capacitance electrode 6 becomes the inclined portion c, and the aperture ratio decreases.

On the other hand, in the case of the embodiment shown in FIG. 1, the withstand voltage between the intersection between the scanning signal line 2 and the data signal line 3 and the overlap between the data signal line 3 and the auxiliary capacitance electrode 6 are set. Since the insulating film 14 for improvement is provided continuously, the insulating film 14 for improving withstand voltage can be formed on the data signal line 3 without disposing the auxiliary capacitance electrode 6 below the data signal line 3 away from the scanning signal line 2. And the auxiliary capacitance electrode 6 can be provided between the overlapping portions, so that the aperture ratio can be prevented from lowering.

In the above embodiment, the insulating film 14 for improving the withstand voltage is formed between the intersections between the scanning signal lines 2 and the data signal lines 3 and between the data signal lines 3 and the auxiliary capacitance electrodes 6.
Although the case where it is provided continuously between the overlapping portions is described, the present invention is not limited to this. For example, as in another embodiment of the present invention shown in FIG. 4, the insulating film 14 for improving the withstand voltage may be provided continuously over almost the entire area in the arrangement direction of the data signal lines 3. In this case, the insulating film 14 for improving the withstand voltage under the data signal line 3 (indicated by reference numerals 3b and 3c in FIG. 2) has no break, so that the data signal line 3 is hardly disconnected. Can be.

In the embodiment shown in FIG. 4, the extension 6b of the auxiliary capacitance electrode 6 further extends along the left side and the right side of the pixel electrode 5, and the right side and the left side of the pixel electrode 5 extend. Extend to a position where it overlaps with the insulating film 14 for improving the withstand voltage. The auxiliary capacitance electrode 6 is formed of a light-shielding metal film. As described above, the right and left sides of the pixel electrode 5 are located outside the extension 6b of the auxiliary capacitance electrode 6 for improving the dielectric strength. By extending to the position where it overlaps with the insulating film 14, the gap between the extension 6b of the auxiliary capacitance electrode 6 and the right side or the left side of the pixel electrode 5 is eliminated,
Light leakage during this time can be eliminated. Therefore, usually, a matrix-shaped light shielding film is formed on the counter substrate side,
The light-shielding film formed on the counter substrate side is formed so as to overlap with the pixel electrode 5 by the positional deviation between the upper and lower glass substrates, so that the necessity of forming the light-shielding film on the counter substrate side is eliminated. Can be improved.

In the embodiment shown in FIG. 4, the gap between the pixel electrode 5 and the scanning signal line 2 may be covered with a light shielding film. In this case, the light shielding film may be formed on the glass substrate 1 side. Alternatively, it may be formed on a counter substrate. In the above-described embodiment, the insulating film 14 for improving the withstand voltage is obtained by forming the intrinsic amorphous silicon film 3a on the gate insulating film 8 and forming the film on the intrinsic amorphous silicon film 3a. It may be formed directly on top.

[0019]

As described above, according to the present invention, since the insulating film for improving the withstand voltage is provided between the overlapping portions of the data signal lines and the auxiliary capacitance electrodes, the data signal lines and the auxiliary capacitance electrodes are not connected to each other. The withstand voltage between the overlapping portions can be improved. Moreover, since the insulating film for improving the withstand voltage is continuously provided between the intersections of the scanning signal lines and the data signal lines and between the overlapping portions of the data signal lines and the auxiliary capacitance electrodes, the aperture ratio is not reduced. can do.

[Brief description of the drawings]

FIG. 1 is a transparent plan view of a main part of a thin film transistor substrate according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line XX of FIG. 1;

FIG. 3 is a transmission plan view similar to FIG. 1 shown for comparison.

FIG. 4 is a transparent plan view of a main part of a thin film transistor substrate according to another embodiment of the present invention.

FIG. 5 is a partially transparent plan view of an example of a conventional thin film transistor substrate.

FIG. 6 is a sectional view taken along the line XX of FIG. 5;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Glass substrate 2 Scan signal line 3 Data signal line 4 Thin film transistor 5 Pixel electrode 6 Auxiliary capacity electrode 10 Channel protective film 14 Insulating film for improving withstand voltage

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H092 GA25 GA26 JA24 JB38 JB69 NA16 5C094 AA10 AA23 AA48 BA03 BA43 CA19 DA15 DB01 DB04 DB10 EA04 EB02 FA01 FA02 FB12 FB14 FB15 5F033 GG04 HH05 HH08 KK05 V15 NN21 XX05 DD02 FF03 GG02 GG15 GG35 HK03 HK09 HK21 HK25 NN02 NN12 NN24 NN72 NN73

Claims (6)

[Claims] A thin film transistor substrate provided with a thin film transistor, a pixel electrode, and an auxiliary capacitance electrode near each intersection of a scanning signal line and a data signal line provided in a matrix; A gate insulating film is provided between the data signal line and an insulating film for improving withstand voltage between intersections of the scanning signal line and the data signal line and between overlapping portions of the data signal line and the auxiliary capacitance electrode. Are continuously provided. 2. The thin film transistor substrate according to claim 1, wherein the insulating film for improving withstand voltage is formed on the gate insulating film. 3. The semiconductor device according to claim 1, wherein a semiconductor thin film is formed along the data signal line on the gate insulating film, and the insulating film for improving withstand voltage is formed on the semiconductor thin film. A thin film transistor substrate characterized by the above-mentioned. 4. The thin film transistor according to claim 1, wherein the insulating film for improving the withstand voltage is provided continuously substantially over the entire area in the arrangement direction of the data signal lines. substrate. 5. The insulating film according to claim 1, wherein the withstand voltage improving insulating film is formed of the same material as a channel protective film forming film for forming a channel protective film of the thin film transistor. A thin film transistor substrate characterized in that: 6. The thin film transistor substrate according to claim 1, wherein a side portion of the pixel electrode is overlapped with the insulating film for improving withstand voltage.