KR100336890B1 - Manufacturing Method of Thin Film Transistor Liquid Crystal Display Device - Google Patents

Abstract

The present invention discloses a method of preventing damage to an active layer and preventing an open line of a data line in a manufacturing process of a thin film transistor liquid crystal display device using five masks. The disclosed method includes sequentially forming a first SiNx film for a gate insulating film and an amorphous silicon film for an active layer on an insulating substrate having a gate formed thereon; Forming an etch stopper made of a second SiNx film on the amorphous silicon film on the gate; Forming a doped amorphous silicon film on an entire surface of the substrate on which the etch stopper is formed; Forming a source and a drain over the doped amorphous silicon film on both sides of the gate; Wet etching the doped amorphous silicon film and the amorphous silicon film using the source and the drain as a mask to form an ohmic layer and an active layer; Forming a second SiNx film for passivation on an entire surface of the substrate on which the ohmic layer and the active layer are formed; And performing a pad opening process by dry etching the third and first SiNx films. In the present embodiment, the gate is formed by depositing an Al-Nd film on an insulating substrate and then wet etching it, and the source and drain are formed of an Al-Nd film or an Al-Nd film.

Description

Method of manufacturing thin film transistor liquid crystal display device

The present invention relates to a method for manufacturing a liquid crystal display device, and more particularly, to a method for manufacturing a thin film transistor liquid crystal display device using five masks.

Active matrix-type liquid crystal displays (AM-LCDs) are thin and are used in various display devices. In such an AM-LCD, a thin film transistor (TFT) is provided as a switching element for each pixel so that individual pixel electrodes are driven independently, and thus the AM-LCD is caused by a reduction in duty ratio. The reduction in contrast does not occur, and the viewing angle does not decrease even when the display capacity increases and the number of lines increases.

On the other hand, in recent years, such an AM-LCD has a 5-mask using a first mask for a gate, a second mask for an etch stopper, a third mask for source and drain, a fourth mask for opening a pad, and a fifth mask for a pixel electrode. By forming through the process, the process is simplified. The process simplification is that after the source and drain are patterned using the third mask, the ohmic layer and the active layer forming process may be performed using the source and the drain as masks.

However, the manufacturing process of the thin film transistor liquid crystal display device (hereinafter referred to as TFT-LCD) using the conventional 5-mask as described above has the advantage of reducing the process steps, while using the source and drain as masks to activate the process. In the process of forming the layer, the etching of the etch stopper may cause damage to the active layer, and as a result, the off current of the thin film transistor may increase. In other words, when the ohmic layer and the active layer are formed using the source and the drain as a mask, the doped amorphous silicon film for the ohmic layer and the amorphous silicon film for the active layer are usually dry-etched. In this process, the etch stopper made of SiNx simultaneously Etching causes damage to the active layer portion below the etch stopper.

In addition, the conventional 5-mask TFT-LCD manufacturing process uses a pad opening process using a fourth mask by wet etching a SiNx film, which is a passivation film material covering the pad, and a SiON film, which is a gate insulating film material. In this process, voids are generated in the photoresist film, and through these voids, etchant intrusion into the data line occurs during subsequent pixel electrode formation, causing the data line to open. There is another problem that the production yield is lowered.

Accordingly, the present invention has been made to solve the above problems, the manufacturing of a TFT-LCD that can prevent the opening of the data line while preventing the damage of the active layer in the production of TFT-LCD using a 5-mask. The purpose is to provide a method.

1A and 1B are cross-sectional views illustrating a method of manufacturing a thin film transistor liquid crystal display device according to an exemplary embodiment of the present invention.

[Description of Code for Major Parts of Drawing]

10: insulated substrate 11: gate

12 gate insulating film 13 amorphous silicon film

13a: active layer 14: etch stopper

15: doped amorphous silicon film 15a, 15b: ohmic layer

16a, 16b: source and drain 17: third mask

In order to achieve the above object, a method of manufacturing a TFT-LCD using a 5-mask according to the present invention includes sequentially forming a first SiNx film for a gate insulating film and an amorphous silicon film for an active layer on an insulating substrate having a gate formed thereon. step; Forming an etch stopper made of a second SiNx film on the amorphous silicon film on the gate; Forming a doped amorphous silicon film on an entire surface of the substrate on which the etch stopper is formed; Forming a source and a drain over the doped amorphous silicon film on both sides of the gate; Wet etching the doped amorphous silicon layer and the amorphous silicon layer using the source and the drain as a mask to form an ohmic layer and an active layer; a second SiNx for passivation on an entire surface of the substrate on which the ohmic layer and the active layer are formed; Forming a film; And performing a pad opening process by dry etching the third and first SiNx films.

In the present embodiment, the gate is formed by forming an Al-Nd film on an insulating substrate and then wet etching it, and the source and drain are formed of an Al-Nd film or a laminated film of an Mo film and an Al-Nd film.

(Example)

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention.

1A and 1B are cross-sectional views illustrating a method of manufacturing a TFT-LCD using a 5-mask according to a sealing example of the present invention.

Referring to FIG. 1A, a first Al-Nd film is deposited as a gate material in order to secure selectivity for dry etching of a SiNx film in a pad open process on an insulating substrate 10, and the first Al-Nd is deposited. A first mask (not shown) for a gate is formed on the film through a photolithography process. Then, the first Al-Nd film is etched by wet etching using the first mask to form the gate 11, and the first mask is removed by a known method.

Next, the gate insulating film 12 made of the first SiNx film, the active silicon layer 13, and the second SiNx film for the etch stopper are sequentially deposited on the entire surface of the substrate 10 on which the gate 11 is formed, A second mask (not shown) for forming an etch stopper is formed on the second SiNx film through a photolithography process. Then, the second SiNx film is etched by wet etching using the second mask to form an etch stopper 14 on the amorphous silicon film 13 above the gate 11, and a second mask by a known method. Remove Here, the material of the gate insulating film 12 is changed from the conventional SiON film to the SiNx film so that the subsequent pad opening process may be performed by dry etching.

Subsequently, the doped amorphous silicon film 15 for the ohmic layer is deposited on the entire surface of the substrate 10 on which the etch stopper 14 is formed, and the selectivity for dry etching of the SiNx film is secured thereon in a subsequent pad opening process. To do this, a second Al-Nd film is deposited as the source and drain material. Here, instead of the second Al-Nd film, the Mo film and the Al-Nd film are sequentially stacked to prevent the occurrence of junction spiking with the active layer. A third mask 17 for source and drain is formed on the second Al-Nd film through a photolithography process, and the second Al-Nd film is etched by wet etching using the third mask 17 to form a source. And drains 16a and 16b.

Referring to FIG. 1B, the doped amorphous silicon film and the amorphous silicon film are wet etched using the source and drain 16a and 16b as a mask, thereby forming ohmic layers 15a and 15b and an active layer 13a. . At this time, since the etching of the doped amorphous silicon film and the amorphous silicon film is conventionally performed by dry etching, damage to the etch stopper 14 is caused in this process, but in the embodiment of the present invention, the doped amorphous silicon film and the amorphous silicon film are amorphous. Since the etching of the silicon film is performed by wet etching, the damage of the etch stopper 14 is hardly caused by the etching selectivity of the SiNx film with respect to the amorphous silicon film, and thus, the damage of the etch stopper 14 is not induced. No damage to the active layer 13a is caused.

Subsequently, after removing the third mask by a known method, although not shown, a passivation film made of third SiNx is formed on the entire surface of the substrate 10, and a photolithography process is performed on the passivation film. Through the fourth mask is formed. Thereafter, the passivation film and the gate insulating film 12 of the pad region are etched by dry etching using the fourth mask to open the pad, and the first mask is removed by a known method. By changing the gate insulating film material to the SiNx film, it is also possible to perform dry etching, and thus no generation of voids caused by wet etching in the pad opening process is caused. Is not triggered.

Next, after depositing an ITO film on the entire surface of the substrate 10, a fifth mask is formed on the ITO film through a photolithography process, and then the ITO film is etched by wet etching using the fifth mask. After forming the pixel electrode, the fifth mask is removed by a known method.

According to the present invention described above, as the active layer is formed by wet etching using the source and the drain as a mask, damage to the active layer due to the etching of the etch stopper layer can be effectively prevented, and therefore, the open current of the thin film transistor. Can be reduced. In addition, by forming the gate insulating film as a SiNx film instead of the SiON film, the pad opening process can be performed by dry etching, thereby preventing the generation of voids in the mask (photoresist film) due to wet etching. As a result, open defects of the data line can be prevented, and the manufacturing yield of the device can be improved.

In addition, the present invention is not limited to the above embodiments and can be carried out in various modifications without departing from the technical gist of the present invention.

Claims (4)

Sequentially forming a first SiNx film for a gate insulating film and an amorphous silicon film for an active layer on an insulating substrate having a gate formed thereon: Forming an etch stopper made of a second SiNx film on the amorphous silicon film on the gate; Forming a doped amorphous silicon film on an entire surface of the substrate on which the etch stopper is formed; Forming a source and a drain over the doped amorphous silicon film on both sides of the gate; Forming an ohmic layer and an active layer by wet etching the doped amorphous silicon layer and the amorphous silicon layer using the source and the drain as masks: Forming a second SiNx film for passivation on an entire surface of the substrate on which the ohmic layer and the active layer are formed; And And dry-etching the third and first SiNx films to perform a pad opening process. The method of claim 1, wherein the gate is formed of an Al-Nd film. The method of claim 1, wherein the source and the drain are formed of an Al-Nd film. The method of claim 1, wherein the source and the drain are formed of a laminated film of an Mo film and an Al-Nd film.