JP3253210B2 - Liquid crystal display element manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a liquid crystal display device. More particularly, the present invention relates to a method of manufacturing a liquid crystal display element using a thin film transistor as a switching element and eliminating a short circuit between a signal line and a pixel electrode.

[0002]

2. Description of the Related Art A liquid crystal display device is formed by sandwiching a liquid crystal material in a gap between two transparent substrates on which a pixel electrode and a corresponding counter electrode are formed.

In an active matrix type liquid crystal display device, each pixel formed in a matrix on one transparent substrate is composed of a pixel electrode and a switching thin film transistor (hereinafter, referred to as TFT). A gate wiring or a source wiring is provided in a column direction, respectively, and connected to a gate electrode or a source electrode of each pixel TFT arranged in a row direction or a column direction, respectively, so that only a specific pixel can be turned on by an external signal. Have been.

FIG. 4 is an explanatory plan view showing a relationship between a pixel electrode of one pixel of such an active matrix type liquid crystal display device and a TFT.

In FIG. 4, reference numeral 1 denotes, for example, an inverted stagger type T
FT, 2 is a pixel electrode, 3 is a TFT of each pixel arranged in a row direction.
4 is a source wiring connected to the source electrode of each pixel arranged in the column direction, and 5 is an additional capacitor for holding a voltage during pulse driving.

In the inverted stagger type TFT 1, a gate electrode is provided on the transparent substrate side with chromium or aluminum, and a semiconductor layer such as amorphous silicon is provided via an insulating layer made of silicon oxide or silicon nitride. Alternatively, the TFT 1 is formed by providing a source electrode and a drain electrode with a metal film such as aluminum. On the other hand, the pixel electrode part has an IT
A pixel electrode made of O, SnO ₂ or the like is formed, and a TFT is formed.
1, the drain electrode and the pixel electrode are connected by a metal film,
When the TFT 1 is turned on, it is connected to the source wiring 4 to which a signal is sent, and can be turned on or off.

The positive stagger type has the same configuration except that the gate electrode and the electrode of the additional capacitance or the storage capacitance are provided not on the transparent substrate side but on a semiconductor layer or a pixel electrode via an insulating film. In any structure, the source electrode, the drain electrode and the pixel electrode are formed on the same surface.

[0008]

In recent liquid crystal display elements, it is required to improve the aperture ratio and display quality, and the area of a pixel electrode is reduced with respect to a non-display area such as a wiring portion or a TFT. There is a tendency to increase the aperture ratio as much as possible. Therefore, the distance between the pixel electrode and the signal line such as the source wiring is also reduced, and is about 10 to 16 μm. Moreover, as described above, since the source wiring and the pixel electrode are on the same surface, conductive rubber may be attached during the manufacturing process,
If a defect occurs in the resist pattern during patterning, a short circuit occurs between the source wiring and the pixel electrode. When such a defect occurs, the pixel does not perform the switching action, the pixel becomes defective, the display panel having a point defect becomes defective, and the yield of the liquid crystal display panel is reduced. In such a case, a repair process for cutting the short-circuit portion using a laser beam may be conventionally provided, but the equipment is expensive and a special process is required, resulting in an increase in cost.

An object of the present invention is to provide a liquid crystal display element which solves such a problem and eliminates a short circuit between a signal line and a pixel electrode.

[0010]

According to a method of manufacturing a liquid crystal display device of the present invention, at least one transparent substrate provided with a switching element, a pixel electrode, a signal line, and an alignment film, and the other transparent substrate provided with at least a counter electrode are provided. and the substrate is stuck by maintaining a constant gap, a method of liquid crystal display device in which a liquid crystal material is injected into the gap, the transparent electrically to the one transparent substrate
The method is characterized in that a step of forming an etching groove between the pixel electrode and the signal line after forming a pixel electrode made of an electric film and a signal line made of a metal film and before forming an alignment film is added.

The step of forming the etching groove can be performed at low cost by using an etching solution for etching the material of the pixel electrode and an etching solution for etching the material of the signal line. This is preferable because a short circuit between the pixel electrode and the pixel electrode can be reliably suppressed.

[0012]

According to the present invention, since a step of forming an etching groove between a signal line and a pixel electrode to reach a layer where the signal line or the pixel electrode is provided is provided, conductive dust is produced during manufacturing. Even if a short circuit occurs between the signal line and the pixel electrode due to adhesion of a resist or a defect in the resist pattern, the short circuit portion is cut by the etching groove, and the short circuit between the two is eliminated.

Moreover, since an etching step is provided uniformly for all products without providing a special step only for short-circuit failure, the number of ordinary etching steps is increased by one, and no special apparatus or special manufacturing process is required. It does not cause a cost increase.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A method for manufacturing a liquid crystal display device according to the present invention will be described below with reference to the drawings. FIG. 1 is an explanatory plan view of one pixel portion of a transparent substrate on a side on which a TFT is provided of a liquid crystal display element manufactured by one embodiment of a method of manufacturing a liquid crystal display element of the present invention. FIG. FIG. 3 is a sectional view taken along line II- of FIG.
FIG. 2 is a sectional view taken along line II.

In FIG. 1, reference numerals 1 to 5 denote the same parts as in FIG. As shown in the sectional view of FIG. 2, the inverted stagger type TFT 1 has a gate electrode 11 provided on a transparent substrate 7 made of glass or the like, and a semiconductor layer 13 and a contact layer for source / drain electrodes via an interlayer insulating film 12. 14. Source electrode 1
5, a drain electrode 16 and a protective film 17 provided thereon. The gate electrodes 11 of the TFTs 1 of each pixel arranged in a matrix and arranged in the row direction are connected to the gate wiring 3, and the TFT 1 for each pixel in the row is controlled by one gate wiring 3. In addition, the source electrode 15 of the TFT 1 of each pixel arranged in the column direction is connected to a source wiring (signal line) 4 provided between the pixels, and the TFT for each pixel in the column receives a signal by one source wiring 4. Given.

On the pixel electrode side, a lower electrode 51 for the additional capacitance 5 is formed of the same material at the same time as the gate electrode 11 on a part thereof, and the pixel electrode 2 is connected to the lower electrode 51 for the additional capacitance via an interlayer insulating film 12. The upper electrode 52 is formed by being provided over the upper portion, and the additional capacitance 5 is formed together with the interlayer insulating film 12. The same applies to the case of a storage capacitor in which a lower electrode is provided at the center of a pixel independently of the gate wiring instead of the additional capacitor 5.

In the liquid crystal display device obtained by the manufacturing method of the present invention, an etching groove 6 is provided between a source wiring 4 and a pixel electrode 2 in a pattern in which pixels including a TFT 1 and a pixel electrode 2 are provided in a matrix. I have. 3, the etching groove 6 is etched until the layer of the pixel electrode 2 or the source wiring 4 is completely removed and the interlayer film 12 is exposed.
Although an alignment film made of polyimide or the like is further provided on the surface of the protective film 17, the groove 6 may be filled with polyimide or the like, or the groove 6 may be left exposed.

Next, an embodiment of a method for manufacturing a liquid crystal display device of the present invention will be described.

First, a TFT 1, a pixel electrode 2, a gate line 3, a source line 4, and an additional capacitor 5 are formed on a transparent substrate 7 such as glass or plastic. That is, a metal film such as aluminum or chromium is deposited on a transparent substrate by sputtering or the like and patterned to form a gate electrode 11, a gate wiring 3, and a lower electrode 5 for additional capacitance.
Form one. Next, an interlayer insulating film 12 made of silicon oxide or silicon nitride is provided by, for example, a CVD method, and then a semiconductor layer such as amorphous silicon and a semiconductor layer doped with impurities are deposited and patterned to form a semiconductor layer 13. I do. The semiconductor layer doped with the impurity is used as an ohmic contact layer of the source / drain electrode, and is performed only on the outer periphery simultaneously with the patterning of the semiconductor layer 13. Next, ITO, SnO ₂ ,
The pixel electrode 2 is formed by depositing a conductive transparent film such as In ₂ O ₃ and patterning it. At the time of this patterning, the end portion is set above the lower electrode 51, and the additional capacitance 5 is formed. Then, a source electrode 15, a drain electrode 16 and a source wiring 4 are formed by depositing and patterning a metal film such as aluminum or chromium by sputtering or the like. When patterning the source electrode 15 and the drain electrode 16,
The semiconductor layer 14 doped with impurities is also separated from the source contact layer 14a and the drain contact layer 14 respectively.
b. The other end of the drain electrode 16 is connected to the pixel electrode. After that, a protective film such as silicon oxide is formed on the entire surface. The steps up to here are the usual steps of forming the TFT 1 and the pixel electrode 2 on the conventional transparent substrate 7.

Next, an etching groove 6 is formed between the source wiring 4 and the pixel electrode 2. In forming the etching groove 6, a resist pattern is provided by a usual photolithography process, and the protective film 17 is removed by dry etching using the resist pattern as a mask. Then source wiring 4
Is etched with an etchant capable of dissolving aluminum, chromium, or the like, which is used as a material for the above. As an etching solution, a mixed solution of acetic acid, nitric acid, and phosphoric acid, a ceric ammonium nitrate solution, or the like can be used. Further, etching is performed with an etching solution that can dissolve ITO or the like that is a material of the pixel electrode. In this case, aqua regia or the like can be used as an etching solution. Thereafter, the resist pattern is peeled and removed by oxygen plasma (ashing) or the like. As described above, by performing etching using both the etching solution for the source wiring and the etching solution for the pixel electrode, even if the cause of the short-circuit failure is on either side, the etching can be always separated at the etching groove 6 portion. Short-circuit failure can be surely eliminated.

The transparent substrate thus formed and the transparent substrate on which the other counter electrode corresponding to the other pixel electrode is formed are adhered at a constant gap, and a liquid crystal material is injected into the gap. Thus, a liquid crystal display element is formed.

[0022]

According to the present invention, a TFT for a liquid crystal display device is provided.
When manufacturing pixel electrodes, the etching groove is formed between the signal line and the pixel electrode by providing an etching process, so no expensive equipment is required and inexpensive wet etching ensures short-circuiting. Defects can be reduced, and in spite of the increase in the number of steps, the yield can be improved and the total cost can be reduced.

[Brief description of the drawings]

FIG. 1 is an explanatory plan view of one pixel portion of a transparent substrate on a side provided with a TFT of a liquid crystal display element manufactured by one embodiment of a method of manufacturing a liquid crystal display element of the present invention.

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

FIG. 3 is a sectional view taken along line II-II of FIG.

FIG. 4 is an explanatory plan view of one pixel portion of a conventional liquid crystal display element.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 TFT 2 Pixel electrode 3 Gate wiring 4 Source wiring (signal line) 6 Etching groove

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Makoto Takamura 21 Ryozaki-cho, Niinin, Ukyo-ku, Kyoto Inside Rohm Co., Ltd. (56) References JP-A-2-73332 (JP, A) JP-A-4-1677437 (JP) JP-A-58-190041 (JP, A) JP-A-64-29821 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02F 1/1362 G02F 1/1343 G02F 1/1333 G02F 1/13 101

Claims (2)

(57) [Claims] At least one transparent substrate provided with at least a switching element, a pixel electrode, a signal line, and an alignment film, and at least another transparent substrate provided with a counter electrode are adhered with a predetermined gap therebetween. A method of manufacturing a liquid crystal display device in which a liquid crystal material is injected into a gap, wherein a pixel electrode made of a transparent conductive film and a signal line made of a metal film are formed on the one transparent substrate, and then the pixel is formed before forming an alignment film. A method for manufacturing a liquid crystal display element, characterized by adding a step of forming an etching groove between an electrode and a signal line. 2. The liquid crystal display according to claim 1, wherein the step of forming the etching groove is performed using an etching solution for etching the material of the pixel electrode and an etching solution for etching the material of the signal line. Element manufacturing method.