KR100843472B1 - Liquid Crystal Display and Fabricating Method Thereof - Google Patents

Abstract

The present invention relates to a liquid crystal display device and a method of manufacturing the same for preventing a defect in copper wiring.

The liquid crystal display device according to the present invention comprises a gate electrode and a gate line formed on a substrate, a gate insulating film formed on the gate electrode and a gate line, an active layer and an ohmic contact layer formed on the gate insulating film, and a source formed on the ohmic contact layer. And a drain electrode and a data line formed to intersect the gate line, wherein the gate electrode, the gate line, the data line, the source and the drain electrode are made of copper (Cu) capable of separating a layer from a lower layer during an etching process. A second metal layer made of any one of titanium (Ti), tantalum (Ta), and nickel (Ni) to compensate for the interfacial properties between the lower layer material and the first metal layer by having a different interfacial property from the metal layer and the first metal layer. It is made, including.

Accordingly, by forming a titanium layer under the copper wiring, it is possible to prevent the film separation during the etching process, and to prevent the chemical reaction with the semiconductor layer at a predetermined temperature or more.

Description

Liquid crystal display and its manufacturing method {Liquid Crystal Display and Fabricating Method Thereof}             

1 is a plan view showing an electrode arrangement for a TFT substrate of a conventional liquid crystal display device.

FIG. 2 is a cross-sectional view of the TFT substrate of FIG. 1 taken along line AA ′. FIG.

3A to 3E are cross-sectional views showing step by step manufacturing methods of the TFT shown in FIG.

4 is a cross-sectional view of a TFT substrate of a liquid crystal display device according to an embodiment of the present invention.

5A to 5G are cross-sectional views showing step by step manufacturing methods of the TFT shown in FIG.

6 is a graph showing the etching rate of a copper (Cu) film according to the concentration of (NH ₄ ) ₂ S ₂ O ₈ aqueous solution.

7 is a graph showing the etching rate of a copper (Cu) film according to the concentration of oxone (Oxone).

8 is a graph showing the etching rate of the titanium (Ti) layer according to the concentration of HF-based fluoride.

      <Brief description of symbols for the main parts of the drawings>

10,30 transparent substrate 12,32 gate electrode

15,35 gate line 14,34 data line

16,36: gate insulating film 18,38: active layer

20,40: ohmic contact layer 22,42: source electrode

24, 44 drain electrode 26, 46 protective layer

28,48 pixel electrode 29,49 contact hole

The present invention relates to a liquid crystal display device and a method for manufacturing the same, and more particularly, to a liquid crystal display device and a method for manufacturing the same so as to prevent defective copper wiring.

 In general, a liquid crystal display (LCD) displays an image by adjusting light transmittance of liquid crystal cells according to a video signal. Among the liquid crystal display devices, an active matrix type in which switching elements are provided for each liquid crystal cell is suitable for displaying a moving image. In the active matrix liquid crystal display device, a thin film transistor (hereinafter referred to as TFT) is mainly used as a switching element.

1 is an electrode arrangement diagram of a TFT substrate of a conventional liquid crystal display device.

FIG. 2 is a cross-sectional view of the TFT substrate illustrated in FIG. 1 taken along the line AA ′.                         

Referring to FIGS. 1 and 2, a pixel electrode formed in a pixel region having a TFT formed at an intersection of the gate line 15 and the data line 14 and an intersection structure of the gate line 15 and the data line 14. And (28).

The TFT is formed by sequentially stacking the gate electrode 12, the gate insulating film 16, the active layer 18, the source and drain electrodes 22 and 24 formed on the TFT substrate 10. The gate electrode 12 is connected to the gate line 15, and the source electrode 22 is connected to the data line 14. The drain electrode 24 is in contact with the pixel electrode through the contact hole 29 formed in the protective layer 26 for protecting the TFT.

The TFT supplies the data signal on the data line 14 to the pixel electrode 28 to drive the liquid crystal cell during the scan pulse supply period applied to the gate electrode 12.

3A to 3E are diagrams showing step by step manufacturing methods of the TFT shown in FIG.

Referring to FIG. 3A, a gate electrode 12 is formed on the TFT substrate 10. The gate electrode 12 is formed together with the gate line 15 by forming a metal thin film by a sputtering method or the like, and then patterning it by a photolithography method including a wet method. As the material of the gate electrode 12, a metal material such as aluminum (Al) or copper (Cu) is used, and an aqueous solution of (NH ₄ ) ₂ S ₂ O ₈ is used as an etching solution.

Referring to FIG. 3B, the gate insulating layer 16, the active layer 18, and the ohmic contact layer 20 are sequentially stacked on the TFT substrate 10 on which the gate electrode 12 is formed.                         

The gate insulating film 16 is formed by depositing an insulating material of silicon nitride or silicon oxide on the transparent substrate 10. An amorphous silicon layer and an amorphous silicon layer doped with impurities on the gate insulating film 16 are sequentially stacked by using a chemical vapor deposition method (hereinafter referred to as "CVD"). The amorphous silicon layer and the amorphous silicon layer doped with impurities are patterned by a photolithography method to form the active layer 18 and the ohmic contact layer 20.

Referring to FIG. 3C, source and drain electrodes 22 and 24 are formed on the gate insulating layer 16 to cover the ohmic contact layer 20. The source and drain electrodes 22 and 24 are formed by depositing a metal layer on the gate insulating layer 16 by the CVD method or the sputtering method to cover the ohmic contact layer 20, and then patterning the photoline by a photolithography method. Is formed together. The source and drain electrodes 22 and 24 use molybdenum alloys such as molybdenum (Mo), MoW, MoTa, or MoNb, and an (NH ₄ ) ₂ S ₂ O ₈ aqueous solution as an etching solution. The ohmic contact layer 20 exposed by using the source and drain electrodes 22 and 24 as a mask is dry etched to expose the active layer 18 between the source and drain electrodes 22 and 24. In the above, the portion corresponding to the gate electrode 12 between the source and drain electrodes 22 and 24 of the active layer 18 becomes a channel.

Referring to FIG. 3D, the protective layer 26 is formed by depositing an insulating material on the entire surface and then patterning the insulating layer. In this case, a contact hole 29 exposing the drain electrode 24 is formed. The protective layer 26 has a low dielectric constant such as an inorganic insulating material such as silicon nitride or silicon oxide or an acrylic organic compound, Teflon, BCB (benzocyclobutene), cytotope, or perfluorocyclobutane (PFCB). It is formed of an organic insulator.

Referring to FIG. 3E, the pixel electrode 28 is formed on the protective layer 26. The pixel electrode 28 may be formed of indium-tin-oxide (hereinafter referred to as "ITO"), indium-zinc-oxide (hereinafter referred to as "IZO"), which is a transparent conductive material. It is formed by depositing and patterning with any one of Indium-Tin-Zinc-Oxide (hereinafter referred to as "ITZO"). The pixel electrode 28 is in electrical contact with the drain electrode 24 through the contact hole 29.

In such a conventional liquid crystal display device, a metal material having good electrical conductivity, particularly copper (Cu), is usually used as a material of the metal electrode. However, when copper (Cu) is used as the gate electrode, the copper (Cu) single layer film does not have good adhesion with the transparent substrate when forming the gate electrode, and thus the copper film is easily peeled off during the etching process. As a result, a poor gate wiring occurs during the process and a problem that causes a decrease in yield occurs.

C) 이상에서 구리 원자가 비정질실리콘층으로 확산(deffusion)되어 TFT의 특성이 저하되는 문제점이 발생한다. 따라서, 소스 및 드레인전극으로 구리(Cu)막을 사용하기가 어렵다.
In addition, when a copper (Cu) film is used as the source and drain electrodes, a predetermined temperature (200)

Above C), a problem occurs in that the copper atoms are diffused into the amorphous silicon layer to deteriorate the characteristics of the TFTs. Therefore, it is difficult to use a copper (Cu) film as the source and drain electrodes.

Accordingly, it is an object of the present invention to provide a liquid crystal display device and a method of manufacturing the same to prevent defects in copper wiring.

According to an aspect of the present invention, a liquid crystal display device includes a gate electrode and a gate line formed on a substrate, a gate insulating film formed on the gate electrode and the gate line, an active layer and an ohmic contact layer formed on the gate insulating film. And a source line and a drain electrode formed on the ohmic contact layer and a data line intersecting the gate line, wherein the gate electrode, the gate line, the data line, the source and drain electrode are formed during an etching process. Titanium (Ti) for compensating the interfacial properties between the lower layer material and the first metal layer by having a first metal layer made of copper (Cu), which can separate the lower layer material and the film, and having a different interface property from the first metal layer, It characterized in that it comprises a second metal layer made of any one of tantalum (Ta) and nickel (Ni).

A liquid crystal display according to the present invention includes a gate electrode and a gate line formed on a substrate, a gate insulating film formed on the gate electrode and the gate line, an active layer and an ohmic contact layer formed on the gate insulating film, and the ohmic contact layer. A source line and a drain electrode formed thereon, and a data line formed to cross the gate line, wherein the gate electrode, the gate line, the data line, the source and drain electrode are formed of a lower layer material at a constant temperature during a manufacturing process. Titanium (Ti), tantalum (Ti) for compensating the interfacial properties between the lower layer material and the first metal layer by having a first metal layer made of copper (Cu) and a different interface property from the first metal layer, Ta) and nickel (Ni), characterized in that it comprises a second metal layer made of.
A method of manufacturing a liquid crystal display according to the present invention includes forming a gate electrode and a gate line on a substrate, forming a gate insulating film on the gate electrode and the gate line, and forming an active layer and ohmic contact on the gate insulating film. Sequentially forming a layer, and forming a source electrode, a drain electrode, and a data line on the ohmic contact layer, and forming the gate electrode, the gate line, the data line, the source and drain electrode. The step includes forming a first metal layer pattern using an etching solution containing Oxone, and forming a second metal layer pattern using a buffer oxide etchant or an F-based compound. Characterized in that.

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In the liquid crystal display according to the present invention, the signal wiring includes a step of sequentially forming a second metal layer and a first metal layer, and sequentially patterning the first metal layer and the second metal layer by a photolithography method. The first metal layer is formed of copper, and the second metal layer is formed of titanium, tantalum or nickel.

Other objects and features of the present invention in addition to the above object will become apparent from the description of the accompanying examples.

Hereinafter, exemplary embodiments of the present invention will be described with reference to FIGS. 4 to 8.

4 is a cross-sectional view of a TFT substrate of a liquid crystal display according to an exemplary embodiment of the present invention.

Referring to FIG. 4, a TFT is formed at an intersection of a gate line and a data line, which is not shown, and a pixel electrode 48 is formed in a pixel region provided in a cross structure of the gate line and the data line.

The TFT is formed by sequentially stacking the gate electrode 32, the gate insulating film 36, the active layer 38, the ohmic contact layer 40, the source and drain electrodes 42 and 44 formed on the TFT substrate 30. . The gate electrode 32 is connected to a gate line (not shown), and the source electrode 42 is connected to a data line (not shown). The drain electrode 44 is in contact with the pixel electrode 48 through the contact hole 49 formed in the protective layer 36.

The gate line and the gate electrode 32 are composed of a first metal layer and a second metal layer.

Similarly, the data lines and the source and drain electrodes 42 and 44 also consist of a first metal layer and a second metal layer.

The TFT supplies a data signal on a data line (not shown) to the pixel electrode 48 to drive the liquid crystal cell during the scan pulse supply period applied to the gate electrode 32.

5A to 5G are diagrams showing step by step manufacturing methods of the TFT shown in FIG.

Referring to FIG. 5A, a first metal layer 32A and a second metal layer 32B are sequentially formed on the transparent substrate 30. The first metal layer uses copper (Cu) having good conductivity, and the second metal layer uses one of titanium (Ti), tantalum (Ta), nickel (Ni), and aluminum (Al). The first metal layer 31 and the second metal layer 30 are formed by sputtering or the like.

Referring to FIG. 5B, the first metal layer 32A is patterned by a photolithography method. Here, an etchant containing oxone (eg, 2KHSO ₅ , KHSO ₄ , K ₂ SO ₄ ) is used as the etchant.

Subsequently, referring to FIG. 5C, the gate electrode 32 including the first and second metal layers 32A and 32B is formed. The gate electrode 32 is formed by patterning the second metal layer 32B after the first metal layer 32A by a photolithography method. As the etchant, a buffer oxide etchant (hereinafter referred to as “BOE”) or an F-based compound (eg, HF, KF, NH ₄ F, NaF) is used.

Referring to FIG. 5D, the gate insulating layer 36, the active layer 38, and the ohmic contact layer 40 are stacked on the TFT substrate 30 on which the gate electrode 32 is formed.

The gate insulating film 36 is formed by depositing an insulating material on the TFT substrate 30 with silicon nitride or silicon oxide. On the gate insulating film 36, an amorphous silicon layer and an amorphous silicon layer doped with a high concentration of impurities are sequentially stacked using the CVD method. The amorphous silicon layer and the amorphous silicon layer doped with impurities are patterned by a photolithography method to form the active layer 38 and the ohmic contact layer 40.

Referring to FIG. 5E, source and drain electrodes 42 and 44 are formed on the gate insulating layer 36 to cover the ohmic contact layer 40. The source and drain electrodes 42 and 44 are composed of the first metal layers 42A and 44A and the second metal layers 42B and 44B.

The source and drain electrodes 42 and 44 are CVD or sputtered to cover the ohmic contact layer 40 on the gate insulating film 36 with the first metal layers 42A and 44A and the second metal layers 42B and 44B. After deposition by means of a photolithography method and formed with data lines. Here, an etchant including oxone (for example, 2KHSO ₅ , KHSO ₄ , and K ₂ SO ₄ ) is used as an etchant for etching the first metal layers 42A and 44A, and the second metal layers 42B and 44B are used. A buffered oxide etchant (hereinafter referred to as "BOE") or an F-based compound (e.g., HF, KF, NH ₄ F, NaF) is used as an etchant. The first metal layers of the source and drain electrodes 42 and 44 use copper (Cu) with good conductivity, and the second metal layer includes titanium (Ti), tantalum (Ta), nickel (Ni), and aluminum (Al). Use either. The ohmic contact layer 40 exposed by using the source and drain electrodes 42 and 44 as a mask is etched to expose the active layer 18 between the source and drain electrodes 42 and 44. The portion corresponding to the gate electrode between the source and drain electrodes 42 and 44 of the active layer 38 becomes a channel.

Referring to FIG. 5F, the protective layer 46 is formed by depositing and then patterning an insulating material. In this case, a contact hole 49 exposing the drain electrode 44 is formed. The protective layer 46 may have a low dielectric constant such as an inorganic insulating material such as silicon nitride or silicon oxide or an acryl organic compound, Teflon, BCB (benzocyclobutene), cytotop, or perfluorocyclobutane (PFCB). It is formed of an organic insulator.

Referring to FIG. 5G, the pixel electrode 48 is formed on the protective layer 46. The pixel electrode 48 is formed by depositing any one of ITO, IZO, and ITZO, which are transparent conductive materials, and then patterning the pixel electrode 48. The pixel electrode 48 is in electrical contact with the drain electrode 44 through the contact hole 29.

6 to 8 are graphs showing etching rates of copper (Cu) or titanium (Ti) wirings by different etching solutions.

6 to 8, each metal material is etched using the etch rate of each etchant as a measure. If the metal is etched too quickly or too slowly, process control is difficult, so the metal should be etched at the proper etch rate.

6 shows the etching rate of the copper (Cu) film according to the concentration of oxone (Oxone).

/min)의 속도로 식각하는 것이 적당하다. As shown in FIG. 6, the Cu film has a concentration of 650 to 5000 (Oxone) using an etchant having a concentration of 0.03 to 0.3 (mol).

/ min) is suitable for etching.

7 shows the etching rate of a copper (Cu) film according to the concentration of (NH ₄ ) ₂ S ₂ O ₈ aqueous solution.

/min)의 속도로 식각하는 것이 적당하다. As shown in FIG. 7, the copper (Cu) film is formed by using an etching solution having a concentration of (NH ₄ ) ₂ S ₂ O ₈ aqueous solution of 0.025 to 0.15 (mol).

/ min) is suitable for etching.

8 shows the etching rate of the titanium (Ti) layer according to the concentration of HF.

/min)의 속도로 식각하는 것이 적당하다.
As shown in FIG. 8, the titanium (Ti) layer is formed using an etching solution having a concentration of 0.1 to 0.5 (mol) of HF.

/ min) is suitable for etching.

As described above, the liquid crystal display and the manufacturing method thereof according to the present invention can prevent the separation of the film during the etching process by forming a titanium layer under the copper wiring, and prevent the chemical reaction with the semiconductor layer at a predetermined temperature or more. Can be.

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the technical spirit of the present invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

Claims (14)

A gate electrode and a gate line formed on the substrate; A gate insulating film formed on the gate electrode and the gate line; An active layer and an ohmic contact layer formed on the gate insulating layer; Source and drain electrodes formed on the ohmic contact layer; And And a data line formed to intersect the gate line. The gate electrode, the gate line, the data line, the source and the drain electrode have a first metal layer made of copper (Cu) capable of separating a film from an underlying layer and an interface property different from that of the first metal layer. And a second metal layer comprising any one of titanium (Ti), tantalum (Ta), and nickel (Ni) to compensate for interfacial properties between the lower layer material and the first metal layer. delete delete A gate electrode and a gate line formed on the substrate; A gate insulating film formed on the gate electrode and the gate line; An active layer and an ohmic contact layer formed on the gate insulating layer; Source and drain electrodes formed on the ohmic contact layer; And And a data line formed to intersect the gate line. The gate electrode, the gate line, the data line, the source and the drain electrode may have a first metal layer made of copper (Cu) and a chemical reaction with a lower layer material at a constant temperature during a manufacturing process, and different interface characteristics from the first metal layer. Liquid crystal display comprising a second metal layer made of any one of titanium (Ti), tantalum (Ta) and nickel (Ni) to compensate for the interfacial properties between the underlying material and the first metal layer by having a Device. delete delete Forming a gate electrode and a gate line on the substrate; Forming a gate insulating film on the gate electrode and the gate line; Sequentially forming an active layer and an ohmic contact layer on the gate insulating layer; Forming a source electrode, a drain electrode, and a data line on the ohmic contact layer; The forming of the gate electrode, the gate line, the data line, the source and the drain electrode may include forming a first metal layer pattern using an etchant including oxone, and a buffer oxide etchant. Etchant) or a method of manufacturing a liquid crystal display device comprising the step of forming a second metal layer pattern using a compound. The method of claim 7, wherein Forming the first and second metal layer patterns, Sequentially forming the second metal layer and the first metal layer, and And patterning the first metal layer and the second metal layer sequentially by a photolithography method. The method of claim 7, wherein And the first metal layer pattern is made of copper (Cu). The method of claim 7, wherein The second metal layer pattern is made of titanium (Ti), tantalum (Ta), nickel (Ni) manufacturing method of a liquid crystal display device, characterized in that. The method of claim 7, wherein The etching solution containing oxone includes 2KHSO ₅ , KHSO ₄ , and K ₂ SO ₄ . The method of claim 7, wherein The F-based compound manufacturing method of a liquid crystal display device comprising any one of HF, KF, NH4F, NAF. delete delete

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