JP3299925B2 - Method for manufacturing active matrix type liquid crystal display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a liquid crystal display, and more particularly to a method for manufacturing an active matrix type liquid crystal display.

[0002]

2. Description of the Related Art In a manufacturing process of an active matrix type liquid crystal display device, static electricity is generated, and when this static electricity is applied to either an address wiring or a data wiring, a high potential difference is generated between the address wiring and the data wiring. Occurs, causing a problem that the active element is electrostatically destroyed and the production yield is remarkably deteriorated.

Therefore, in a method of manufacturing an active matrix type liquid crystal display device, static electricity is applied to the address wiring or the data wiring by forming a short-circuit wiring made of a metal film and short-circuiting the address wiring and the data wiring. Even in such a case, the potential difference between the address wiring and the data wiring is eliminated to prevent electrostatic breakdown of the active element.

The manufacturing process of an active matrix type liquid crystal display device includes a first half process of forming an active element and a second half process of forming a liquid crystal display panel. It is necessary to short-circuit the address wiring and the data wiring until all the manufacturing steps are completed.

Therefore, a short-circuit state between address wirings, between data wirings, and between an address wiring and a data wiring,
In addition, the inspection of the electrical characteristics of the active element is generally performed after removing the short-circuit wiring after completion of all the manufacturing steps. For this reason, electrical inspection cannot be performed at the end of the first half process, and a defective product that has caused electrostatic breakdown in the first half process must be processed until the final process. As a result, there is a serious problem that the production yield is significantly reduced and the production cost is increased.

In order to solve this problem, Japanese Patent Laid-Open Publication No.
As disclosed in Japanese Patent No. 1618, a technique of forming a short-circuit wiring with a semiconductor film and irradiating or blocking light to change the resistance value of the semiconductor film to enable an electrical inspection during a manufacturing process. Proposed.

Further, as disclosed in Japanese Patent Application Laid-Open No. 4-120522, a short-circuit wiring is formed of a semiconductor film, and the characteristic that the semiconductor film has nonlinearity in the IV characteristic is used. A technology has been proposed in which a driving voltage is maintained at a resistance value that does not hinder driving, and when a high voltage such as static electricity is applied, the conductivity is secured so that electrostatic breakdown does not occur.

[0008]

SUMMARY OF THE INVENTION The above-mentioned Japanese Patent Application Laid-Open No. 2-6 / 1990
The technique disclosed in Japanese Patent No. 1618 utilizes the fact that the resistance value decreases when light is applied to a semiconductor film, and the resistance value increases when light is shielded.

For this reason, it is necessary to perform the electrical inspection in a state where the light is shielded, and there is a problem that it is necessary to add a light shielding facility to the inspection apparatus. In other steps, the short-circuit wiring does not function unless light is constantly irradiated to the short-circuit wiring. Therefore, in a process using a device which is not irradiated with light, such as a film forming chamber of a CVD apparatus or a sputtering apparatus, the short-circuit wiring is not used. Does not work. Furthermore, there is a problem that this method cannot be used unless a facility capable of constantly irradiating the short-circuit wiring is provided in a process using a rubbing device that easily generates static electricity.

In the technique disclosed in Japanese Patent Application Laid-Open No. 4-120522, a high voltage which causes electrostatic breakdown is applied by utilizing the characteristic that the semiconductor film has nonlinearity in the IV characteristics. Only when this is done, the short-circuit wiring is made conductive.

For this reason, there is a problem that it is difficult to control the function of the short-circuit wiring due to the quality of the semiconductor film and the generation of photocurrent. Further, even after the completion of the active matrix type liquid crystal display device, short-circuit wiring exists, and noise currents such as photocurrent and uncertainties such as short-circuit between address wiring and data wiring are attached to the product. .

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and an active matrix type liquid crystal capable of reliably functioning a short-circuit wiring while enabling an electrical inspection during a manufacturing process. It is an object to provide a method for manufacturing a display device.

[0013]

According to a first aspect of the present invention, there is provided a method of manufacturing an active matrix type liquid crystal display device, comprising the steps of: providing a plurality of address wirings on a substrate having an insulating surface; And forming a plurality of data lines orthogonal to the address lines, and forming a thin film transistor near an intersection of the address lines and the data lines. A step of forming a short-circuit wiring made of polysilicon to prevent electrostatic breakdown of the thin-film transistor by connecting the data wiring, and a step of irradiating the short-circuit wiring with a laser beam to form amorphous silicon, and performing an electrical test; Irradiating the short-circuit wiring with a laser beam to form polysilicon after the inspection. It is characterized.

According to a second aspect of the present invention, there is provided a method of manufacturing an active matrix type liquid crystal display device according to the first aspect, wherein the resistance value of the short-circuit wiring is 1 MΩ or less when polysilicon is used. And is characterized by being 1 GΩ or more in the case of amorphous silicon.

According to the method of manufacturing an active matrix type liquid crystal display device of the present invention, a step of connecting an address wiring and a data wiring to form a short-circuit wiring made of polysilicon to prevent electrostatic breakdown of a thin film transistor; A step of irradiating a laser beam to amorphous silicon to perform an electrical inspection, and after the inspection, a step of irradiating the laser beam to the short-circuit wiring and forming a polysilicon, in the process up to the electrical inspection Is to ensure that the short-circuit wiring functions properly by keeping the resistance of the short-circuit wiring low, and to make the electrical inspection possible by making the resistance of the short-circuit wiring sufficiently high in the electrical inspection process. By keeping the resistance value of the short-circuit wiring low again in the step (3), the short-circuit wiring can function reliably.

Furthermore, the resistance value of the short-circuit wiring is 1 MΩ or less for polysilicon and 1 GΩ or more for amorphous silicon, so that the short-circuit wiring can be reliably functioned in processes other than the electrical inspection. In the step of performing the electrical inspection, the electrical inspection can be performed without affecting the characteristics of the active element.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. 1 is a process diagram showing a cross section of a main part according to the present invention, FIG. 2 is a plan view according to FIG. 1,
FIG. 3 is a sectional view showing a main part of another example according to the present invention, and FIG. 4 is a cross-sectional view showing a main part of still another example according to the present invention.

As shown in FIGS. 1A and 2, a short ring 1 made of an N ⁺ type or P ⁺ type polysilicon film is formed on an insulating substrate 4 made of glass or the like. The resistance value of the short ring 1 is 1 MΩ or less. Then, an insulating film 2 is formed on the short ring 1.

The insulating film 2 is a protective film for the short ring 1, that is, it prevents the short ring 1 from jumping or spontaneously oxidizing due to laser beam irradiation performed later. Has no effect on functionality. When the insulating film 2 is formed, a contact hole 6 for connecting the short ring 1 to an address wiring and a data wiring 3 to be formed later is formed in the insulating film 2.

Thereafter, address wiring and data wiring 3
To form Thus, the short ring 1 is formed so as to connect all the address wirings and the data wirings 3. The order of the above steps is not particularly limited.

Next, in a step requiring temporary removal or cutting of the short ring 1 for performing an electrical inspection,
As shown in FIG. 1B, a laser beam is irradiated on the short ring 1 made of an N ⁺ type or P ⁺ type polysilicon film before the step, and a part of the short ring 1 is converted into amorphous silicon 5. The resistance value of the short ring 1 is increased to 1 GΩ or more, and the current flowing through the short ring 1 is reduced to a level that does not cause a problem in electrical inspection.

In order for the polysilicon forming the short ring 1 to be amorphous silicon 5,
It is preferable to irradiate the 00 nm short ring 1 (polysilicon) with a laser beam having an energy density of about 300 to 500 mJ / cm ² .

When the electrical inspection process is completed, the amorphous silicon 5 is irradiated with a laser beam to form polysilicon, and the resistance of the short ring 1 is reduced to 1 MΩ or less to restore the function of the short ring 1. .

In order to make the amorphous silicon 5 polysilicon, the energy density of the amorphous silicon 5 having a thickness of 500 nm is 200 to 400 mJ / c.
It is preferable to irradiate a laser beam of about m ² .

The active matrix type liquid crystal display device is manufactured in this manner. The short ring 1 may be finally removed by etching or the like, or a laser beam is irradiated to form the amorphous silicon 5, and the short ring 1 is formed. 1 may be increased to 1 GΩ or more, and the current flowing through the short ring 1 may be reduced so as not to affect the characteristics of the active element, and may be left as it is.

In this embodiment, the case where the insulating film 2 is formed has been described. However, as shown in FIG. 3, after the short ring 1 is formed on the insulating substrate 4, the end of the short ring 1 and the address are formed. The address wiring and the data wiring 3 may be formed so that the wiring and the end of the data wiring 3 overlap with each other, or the address wiring and the data wiring 3 are formed on the insulating substrate 4 as shown in FIG. Then, the ends of the address wiring and data wiring 3 and the short ring 1
The short ring 1 may be formed such that the end of the short ring 1 overlaps with the end of the short ring.

[0027]

As described above, according to the method of manufacturing the active matrix type liquid crystal display device of the present invention, the short-circuit wiring for connecting the address wiring and the data wiring to prevent the electrostatic breakdown of the thin film transistor is formed. Forming a silicon layer, irradiating the short-circuit wiring with a laser beam to form amorphous silicon, and performing an electrical inspection; and, after the inspection, irradiating the short-circuit wiring with a laser beam to form polysilicon. Accordingly, the short-circuit wiring can be reliably functioned and an electrical test can be performed, so that electrostatic breakdown can be reliably prevented, and a defective product can be prevented from being brought to the latter half of the process.

Further, the resistance value of the short-circuit wiring is 1 MΩ or less for polysilicon and 1 GΩ or more for amorphous silicon, so that the short-circuit wiring can function more reliably and can be electrically inspected. Therefore, electrostatic breakdown can be more reliably prevented, and defective products can be prevented from being brought to the latter half of the process.

[Brief description of the drawings]

1 (a) and 1 (b) are process drawings showing a cross section of a main part according to the present invention.

FIG. 2 is a plan view according to FIG. 1;

FIG. 3 is a cross-sectional view showing a main part of another example according to the present invention.

FIG. 4 is a sectional view showing a main part of still another example according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Short ring 2 Insulating film 3 Address wiring and data wiring 4 Insulating substrate 5 Amorphous silicon 6 Contact hole

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-1-303416 (JP, A) JP-A-62-198826 (JP, A) JP-A-64-64250 (JP, A) JP-A-9-96 172186 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G02F 1/1368

Claims (2)

(57) [Claims] 1. A plurality of address wirings and a plurality of data wirings orthogonal to the address wirings are formed on a substrate having an insulating surface, and a thin film transistor is formed near an intersection between the address wirings and the data wirings. A method for manufacturing an active matrix type liquid crystal display device to be formed, wherein a step of connecting the address wiring and the data wiring to form a short-circuit wiring made of polysilicon to prevent electrostatic breakdown of the thin-film transistor; An active matrix type liquid crystal display device, comprising: a step of irradiating a beam to form amorphous silicon to perform an electrical inspection; and a step of irradiating the short-circuit wiring with a laser beam to form polysilicon after the inspection. Manufacturing method. 2. The active matrix type liquid crystal display device according to claim 1, wherein the resistance value of the short-circuit wiring is 1 MΩ or less in the case of polysilicon and 1 GΩ or more in the case of amorphous silicon. Method.