KR100577777B1 - Method for forming transfer of TFT LCD - Google Patents

Abstract

The present invention relates to a transfer forming method for electrically conducting a lower substrate and an upper substrate. According to another aspect of the present invention, there is provided a method of forming a thin film transistor liquid crystal display device, the method including: providing a glass substrate having a gate electrode formed on an active region having a transfer forming region around the gate electrode and having a gate insulating film covering the gate electrode; Sequentially depositing an amorphous silicon layer and a source / drain metal layer on the insulating layer, and etching the source / drain metal layer and the amorphous silicon layer to form a channel region and a source / drain electrode on the gate electrode to form a thin film transistor. And forming a source / drain metal layer pattern including an amorphous silicon layer in the transfer forming region, depositing a protective film on the entire surface of the resultant, and etching the protective film to expose a portion of the thin film transistor. Source / drain formed in the transfer-forming region at the same time Exposing the metal layer pattern for the metal layer; depositing an ITO metal layer for the pixel electrode on the passivation layer; etching the ITO metal layer to form a pixel electrode in contact with the thin film transistor in an active region; Exposing only a central portion of the upper surface of the source / drain metal layer pattern, and forming a conductive metal material on the exposed source / drain metal layer pattern.

Description

Method for forming transfer of thin film transistor liquid crystal display device {Method for forming transfer of TFT LCD}

The present invention relates to a thin film transistor liquid crystal display device, and more particularly, to a method of forming a transfer for electrically conducting a lower substrate and an upper substrate.

Liquid crystal displays (hereinafter, LCDs) used in display devices such as televisions and graphic displays have been developed in place of the CRT (Cathode-ray tube). In particular, a TFT LCD having a thin film transistor (TFT) as a switching element in each pixel arranged in a matrix form is comparable to a CRT because of the advantages of having high-speed response characteristics and suitable for high pixel count. It is greatly contributing to realizing high screen quality, large size, and color.

In general, a TFT LCD includes a lower substrate on which a pixel electrode made of a thin film transistor and an ITO metal is formed, and an upper substrate on which a color filter and a counter electrode are formed. The liquid crystal is filled between them as the basic structure.

In addition, the TFT LCD having the above-described configuration forms a transfer made of a conductive material in order to electrically conduct the lower substrate and the upper substrate, that is, to form a uniform potential difference. As shown in FIG. 3, the transfer 30 is formed on the left and right (or up and down) of the liquid crystal panel formed by the lower substrate 10 and the upper substrate 20 bonded together.

On the other hand, the lower substrate of the TFT LCD as described above is usually seven etching masks, for example, as is well known to those skilled in the art, the first mask for forming the gate, the second mask for forming the etch stopper, the active layer It is manufactured by using a third mask for forming, a fourth mask for forming a pixel electrode, a fifth mask for forming a channel region, a sixth mask for forming a source / drain electrode, and a seventh mask for forming a protective film. In this case, there is a problem in that process time and cost are consumed a lot.

Therefore, recently, five etching masks, for example, a first mask for forming a gate, a second mask for forming an etch stopper, a third mask for forming a source / drain electrode, and a contact hole for exposing a drain electrode are formed. The lower substrate is manufactured by using a fourth mask for forming the fifth electrode and a fifth mask for forming the pixel electrode. Accordingly, unlike the process using seven etching masks, the ITO metal layer is formed as the top layer.

By the way, when manufacturing the lower substrate of the TFT LCD using the five etching masks as described above, as shown in Figure 2, the transfer 30 is formed on the ITO metal layer 8, wherein, ITO Since the contact resistance between the metal layer 8 and the transfer 30 is large, distortion of the common signal occurs due to voltage loss, and as a result, there is a problem in that the image quality of the TFT LCD is deteriorated.

In FIG. 2, reference numeral 1 denotes a glass substrate, 2 a gate insulating film, 3 an amorphous silicon layer, 4 a source / drain metal layer pattern, and 6 a protective film.

On the other hand, to solve this problem, conventionally, the ITO metal layer deposited in the region where the transfer is to be formed is removed by a wet etching process, but in this case, the ITO etchant flows downward along the side of the source / drain metal layer. There was another problem that additional defects are generated by damaging the underlying films.

Accordingly, the present invention has been made to solve the above-mentioned conventional problems, and in order to prevent the distortion of the common signal due to voltage loss, the lower layer due to ITO etchant penetration in removing the ITO metal layer formed in the transfer forming region. It is an object of the present invention to provide a method for forming a transfer of a TFT LCD which can prevent damage of the same.

The transfer forming method of the TFT LCD of the present invention for achieving the above object is to provide a glass substrate having a gate electrode formed on the active region having a transfer forming region in the periphery, the entire surface of the gate insulating film is applied to cover the gate electrode step; Sequentially depositing an amorphous silicon layer and a source / drain metal layer on the gate insulating layer; The source / drain metal layer and the amorphous silicon layer are etched to form a channel region and a source / drain electrode on the gate electrode to form a TFT, and a source / drain metal layer pattern including an amorphous silicon layer in the transfer forming region. Forming; Depositing a passivation layer on the entire surface of the substrate resulting from forming the thin film transistor and forming a source / drain metal layer pattern including an amorphous silicon layer in a transfer forming region; Etching the passivation layer to expose a portion of the TFT and simultaneously exposing a source / drain metal layer pattern formed in a transfer formation region; Depositing an ITO metal layer for a pixel electrode on the passivation layer; Etching the ITO metal layer to form a pixel electrode in contact with the TFT in an active region, and exposing only the center of the upper surface of the source / drain metal layer pattern formed in the transfer formation region; And forming a conductive metal material on the source / drain metal layer pattern in which the center of the upper surface is exposed.

According to the present invention, by removing the ITO metal layer so as to expose only the center of the upper surface of the source / drain metal layer pattern in the region where the transfer is to be formed, it is possible to prevent the penetration of the ITO etchant into the lower portion of the ITO etchant. Damage to the underlying films can be prevented.

(Example)

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a view for explaining a transfer forming method of a TFT LCD according to an embodiment of the present invention. Here, the same parts as in Fig. 2 are denoted by the same reference numerals.

As shown, a gate electrode (not shown) is formed in an active region having a transfer forming region around it, and a gate insulating film covering the gate electrode to prevent the gate electrode from coming into contact with another metal layer formed later. (2) is provided with a glass substrate 1 coated on the entire surface.

Next, an a-Si layer 4 and a source / drain metal layer 4 for forming a channel region and a source / drain electrode are sequentially deposited on the gate insulating film 2, and then a source / drain forming mask is deposited. The photo-process is used to etch the source / drain metal layer and the lower a-Si layer to form a source / drain metal layer pattern 4 including an a-Si layer 4 in the region where the transfer is to be formed. . Although not shown, a channel region and a source / drain electrode are formed on the gate electrode in the active region by the photo process to form a TFT.

Next, in order to protect the TFT formed in the active region, a protective film 6 made of, for example, a silicon nitride film is formed on the entire surface of the glass substrate 1, and then the portion where the transfer is to be formed through an etching process. Remove the protective film portion formed in the. Here, the etching process of removing the protective film portion on the region where the transfer is to be formed is performed together with the etching process at the time of forming the contact hole for exposing the drain electrode of the TFT in the active region.

Thereafter, an ITO metal layer is deposited on the passivation layer 6 as a top layer, and then the ITO metal layer is etched to form a pixel electrode in contact with the drain electrode of the TFT exposed in the active region, and at the portion where the transfer is to be formed. The deposited ITO metal layer portion is removed to form the ITO metal layer pattern 8a.

At this time, the etching process is used to produce a separate mask, in particular, not to remove all the ITO metal layer deposited in the region where the transfer is to be formed, is deposited on the center of the source / drain metal layer pattern (4) Proceed to remove only the portion of the ITO metal layer.

This etching process is difficult to fabricate the mask, on the other hand, the etching liquid used during the etching of the ITO metal layer due to the process proceeds to expose only the center of the upper surface of the source / drain metal layer 4, the source / drain metal layer The phenomenon of infiltration to the lower side along the side of the pattern 4 is prevented, so that the occurrence of damage due to ITO etching of the bottom films can be prevented.

That is, in the case where all the ITO metal layers deposited in the region where the transfer is to be formed are etched, the etchant for removing the ITO metal layer is penetrated downward along the side of the source / drain metal layer as in the prior art, thereby damaging the side portions of the lower layers. However, in the case of removing only the portion of the ITO metal layer deposited on the center of the upper surface of the source / drain metal layer as in the present invention, it is possible to block the penetration of the ITO etchant into the lower portion, thereby causing damage to the underlying films by the ITO etchant. Will almost never be.

Subsequently, a transfer 30 made of a conductive material is formed on the region where the transfer is exposed through the above etching process, preferably, the metal layer pattern 4 for source / drain.

When the transfer is formed in the above manner, since the transfer is directly formed on the source / drain metal layer having excellent conductivity rather than the ITO metal layer, the contact resistance between the source / drain metal layer and the transfer is prevented from increasing. As a result, the voltage loss caused by the increase in the contact resistance can be prevented, and as a result, the distortion of the common signal can be prevented and the deterioration of the image quality of the TFT LCD can be prevented.

In addition, by etching away only a part of the ITO metal layer, it is possible to prevent the underlying films from being damaged due to penetration of the ITO etchant.

As described above, the present invention provides a method for manufacturing a TFT LCD using a five-mask process for forming an ITO metal layer as a top layer. By selectively removing only the portion of the ITO metal layer deposited on the substrate, it is possible to prevent the penetration of the lower portion of the ITO etchant through the side of the source / drain metal layer pattern, thereby preventing damage to the underlying films by the ITO etchant. Can be.

In addition, according to the present invention, a voltage loss is caused by an increase in contact resistance by forming a transfer for electrically conducting an electrical connection between the lower substrate and the upper substrate on the source / drain metal layer instead of the ITO metal layer. This can be prevented, and therefore, the reliability thereof can be improved due to being able to prevent the deterioration of the image quality of the TFT LCD.

Meanwhile, although specific embodiments of the present invention have been described and illustrated, modifications and variations can be made by those skilled in the art. Accordingly, the following claims are to be understood as including all modifications and variations as long as they fall within the true spirit and scope of the present invention.

1 is a view schematically showing a liquid crystal panel on which a transfer is formed.

Figure 2 is a detailed view of the portion A of Figure 1 for explaining the conventional problem.

3 is a view for explaining a transfer forming method of a thin film transistor liquid crystal display device according to an embodiment of the present invention.

(Explanation of symbols for the main parts of the drawing)

1 glass substrate 2 gate insulating film

3: amorphous silicon layer 4: source / drain metal layer

6: protective film 8a: ITO metal layer

30: transfer

Claims (1)

Providing a glass substrate on which a gate electrode is formed in an active region having a transfer forming region in a periphery of which a gate insulating film covering the gate electrode is applied; Sequentially depositing an amorphous silicon layer and a source / drain metal layer on the gate insulating layer; The source / drain metal layer and the amorphous silicon layer are etched to form a channel region and a source / drain electrode on the gate electrode to form a thin film transistor, and a source / drain metal layer pattern including an amorphous silicon layer in the transfer forming region. Forming a; Depositing a passivation layer on the entire surface of the substrate product in which the thin film transistor is formed and a source / drain metal layer pattern including an amorphous silicon layer is formed in a transfer formation region ; Etching the passivation layer to expose a portion of the thin film transistor and simultaneously exposing a source / drain metal layer pattern formed in a transfer formation region; Depositing an ITO metal layer for a pixel electrode on the passivation layer; Etching the ITO metal layer to form a pixel electrode in contact with the thin film transistor in an active region, and exposing only a central portion of the upper surface of the source / drain metal layer pattern formed in the transfer formation region; And Forming a conductive metal material on the source / drain metal layer pattern in which the center of the upper surface is exposed; A transfer forming method of a thin film transistor liquid crystal display device comprising a.