KR20110076578A - Method for fabricating line and method for fabricating liquid crystal display device of using the same - Google Patents

Abstract

PURPOSE: A wiring forming method and method for manufacturing a liquid crystal display device using the same are provided to form a narrower width wire and an electrode than physical resolution of the light exposing device by using a mask used in an existing liquid crystal display device manufacturing process and a light exposing device. CONSTITUTION: A wire forming method includes as follows. A first step forms a first metal layer on a substrate. A second step forms a photosensitive film layer which has a reverse tapper by processing a phenomena process and light exposing and spraying a negative photosensitive film on the metal film. A third step forms a second metal film on the substrate which has the photosensitive film pattern. A fourth step forms a first wire(210) and a second wire(211) by processing an etching process by enabling a second metal film formed on the first metal film with the photosensitive pattern as a mask. A fifth step removes the second metal film. A sixth step removes the photosensitive pattern.

Description

Method for fabricating line and Method for fabricating liquid crystal display device of using the same

The present invention relates to a wiring forming method and a method for manufacturing a liquid crystal display device using the same.

Liquid crystal displays have been attracting attention as an alternative means of overcoming the shortcomings of Cathode-Ray Tubes (CRTs) due to their advantages such as miniaturization, light weight, and low power consumption. Currently, almost all information requiring display devices is required. It is being installed in the processing equipment.

Such a liquid crystal display generally applies a voltage to a specific molecular array of a liquid crystal, converts it into a different molecular array, and converts a change in optical properties into a visual change, and is a display device using modulation of light by a liquid crystal cell.

The liquid crystal display device includes a manufacturing process of a panel upper substrate and a lower substrate accompanied with a process of forming a liquid crystal cell forming a pixel unit, a process of forming and rubbing an alignment layer for liquid crystal alignment, and a process of forming an upper substrate and a lower substrate. It is completed through various processes such as a bonding process, a process of injecting and encapsulating liquid crystal between the bonded upper substrate and the lower substrate.

In the lower substrate manufacturing process, a plurality of gate wirings and a data wiring are arranged to define a unit pixel region, and in each pixel region, a thin film transistor (TFT) and a pixel electrode, which are switching elements, are formed. do. The thin film transistor is turned on by a driving signal supplied through a gate wiring, and has a switching function of supplying a graphic signal supplied from the data wiring to a pixel electrode. The graphic signal supplied to the pixel electrode generates an electric field for rotating the liquid crystal to modulate external light or internal light to display an image.

In particular, as liquid crystal displays have become larger and higher in resolution, they have been developed to have high opening ratio and high transmittance characteristics.

In order for the liquid crystal display to have high opening ratio and high transmittance characteristics, it is preferable to form a narrow width of the gate wiring, the data wiring, the pixel electrode, and the common electrode disposed in the predetermined pixel region.

However, due to the physical characteristics of the exposure apparatus used in the liquid crystal display device manufacturing method, the wiring width or the electrode width is hardly formed to be 4 μm or less. That is, a wiring width or an electrode width that can be formed by forming a metal film on a substrate, then applying a photoresist film, and performing a mask process to perform an exposure, development, and etching process is about 4 μm.

Therefore, in order for a liquid crystal display to have high opening ratio and high transmittance characteristics, a method of reducing wiring or electrode width formed in a pixel area is required.

The present invention provides a wiring forming method capable of forming wires and electrodes having a width much narrower than the physical resolution of the exposure equipment using masks and exposure equipment used in a conventional liquid crystal display device manufacturing process.

In particular, the present invention provides a method of manufacturing a liquid crystal display device having a characteristic of low power, high opening ratio, and high transmittance by narrowing the distance between electrodes formed in the pixel region of the liquid crystal display device.

According to a first aspect of the present invention, there is provided a wiring forming method including: forming a first metal film on a substrate; Applying a negative photoresist film on the metal film, and performing an exposure and development process to form a photoresist pattern having a reverse taper structure; Forming a second metal film on the substrate on which the photosensitive film pattern is formed; Performing an etching process using the photosensitive film pattern and the second metal film formed on the first metal film as a mask to form a first wiring and a second wiring; Removing the second metal film; And removing the photoresist pattern.

In addition, a method of manufacturing a liquid crystal display device according to a second embodiment of the present invention may include forming a metal film on a substrate and then performing a first mask process to form a gate electrode and a gate wiring; A gate insulating film, an amorphous silicon film, a doped amorphous silicon film, and a source / drain metal film are sequentially formed on the substrate on which the gate electrode is formed, and then a second mask process is performed to form source / drain electrodes, active layers, and data lines. Forming; Forming a protective film on the entire surface of the substrate on which the source / drain electrodes and the like are formed, and then performing a third mask process to form contact holes; And performing a fourth mask process on the passivation layer according to claim 1, wherein the first wiring and the second wiring of claim 1 are formed in a pixel region, and the first wiring comprises a pixel electrode, a first electrode; The two wirings are characterized in that they are common electrodes.

The wiring forming method of the present invention has an effect of forming a wiring or an electrode having a width smaller than the wiring width that can be formed by a mask and exposure equipment that is used by using a negative photosensitive film and an etching process.

In addition, the manufacturing method of the liquid crystal display of the present invention has the effect of realizing low power driving, high opening ratio, and high transmittance by narrowing the distance between electrodes formed in the pixel region without adding equipment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following embodiments are provided by way of example so as to fully convey the spirit of the invention to those skilled in the art. Therefore, the present invention is not limited to the embodiments described below, but may be embodied in other forms. In the drawings, the size and thickness of the device may be exaggerated for convenience. Like numbers refer to like elements throughout.

1A to 1E illustrate a wiring forming process according to a first embodiment of the present invention.

In the following description, the wiring is formed by depositing a metal film and performing a mask process to form a wiring, but the wiring may be a pixel electrode or a common electrode of a liquid crystal display.

In particular, when applied to the electrode forming process, it is applicable to a structure in which a common electrode and a pixel electrode are formed together on a thin film transistor (TFT) substrate, such as IPS (In-Plane Switching) mode and FFS (Fringe Field Switching) mode. Can be.

1A to 1E, a transparent conductive film 110 is formed on the insulating substrate 100. Thereafter, a photosensitive film is coated on the transparent conductive film 110, and then a mask process is performed.

The transparent conductive film 110 uses any one of ITO, ITZO, and IZO.

Photoresistors used in the mask process include a positive photoresist film and a negative photoresist film. When the positive photoresist film is irradiated with a mask that is divided into a light transmission region and a non-transmission region that does not transmit light, the photoresist film in a region corresponding to the transmission region of the mask is removed in a developing process, and the mask The photosensitive film in the region corresponding to the non-transmissive region of has properties remaining in the developing process.

The negative photoresist film has a property opposite to that of the positive photoresist film. That is, the photosensitive film in the region corresponding to the transmissive region of the mask remains in the developing process, and the photosensitive film in the region corresponding to the non-transmissive region of the mask has the property of being removed in the developing process.

In the present invention, a wiring is manufactured by using a negative photosensitive film having a reverse taper structure after the developing step. The reverse taper structure is defined as a structure in which the width of the upper side is larger than the width of the lower side.

As described above, when the photosensitive film is formed on the transparent conductive film 110, the photosensitive film pattern 200 is formed by performing exposure and development processes. The photosensitive film pattern 200 has an inverse taper structure in which an upper width is wider than a lower width d3.

The lower width of the photosensitive film pattern 200 is about 4 μm, and the lower edge and the upper edge distance d1 are about 1 μm. That is, the distance from the top edge of the photosensitive film pattern 200 to the edge of the bottom surface is about 1 μm. In addition, the distance d2 between the upper edge of the photoresist pattern 200 and the upper edge of the adjacent photoresist pattern 200 has a distance of about 3 μm. Therefore, the lower edge distance d4 of the adjacent photoresist pattern 200 facing the lower edge of the photoresist pattern 200 has a distance of about 5 μm.

As such, when the photosensitive film pattern 200 is formed on the transparent conductive film 110, as illustrated in FIG. 1B, the metal film 130 is formed. The metal film 130 may be formed of Mo, Al, Cu, W, Ag, or an alloy thereof.

The metal layer 130 is formed in a pattern separated on the photosensitive film pattern 200 and the transparent conductive film 110 between the photosensitive film patterns 200.

Therefore, the width d5 of the metal film 130 formed on the transparent conductive film 110 is 3 μm or more wider than d2. This is because when the metal film 130 is formed on the transparent conductive film 110, the metal film 130 is formed in the space between the upper and lower surfaces of the photosensitive film pattern 200.

As described above, when the metal film 130 is formed on the insulating substrate 100, as shown in FIGS. 1C and 1D, the metal film 130 formed on the photosensitive pattern 200 and the transparent conductive film is used as a mask. The transparent conductive film is etched to form the first wiring 210 and the second wiring 211. The first wiring 210 and the second wiring 211 may be a pixel electrode and a common electrode of the liquid crystal display.

The first wiring 210 is a wiring formed under the photosensitive film pattern 200, and the second wiring 211 is a wiring formed under the metal film 130.

Then, as shown in FIG. 1E, when the photosensitive film pattern is removed, only the first and second wirings 210 and 211 remain on the insulating substrate 100.

The widths d6 and d8 of the first and second wirings 210 and 211 are etched in the form of undercuts under the photosensitive film pattern 200 and the metal film 130 during the etching process. The widths d6 and d8 of the second wiring 211 have 2.5 μm narrower than d3 and d2. In addition, the distances d7 and 2 μm between the first wiring 210 and the second wiring 211 are wider than the width of d1 due to the undercut during etching.

When the mask, the exposure and development processes are adjusted, and the etching process (time) is adjusted, the wiring width and the distance between the wirings are 1 to 3 μm. As a result, it is possible to form a wiring or an electrode having a width smaller than the smallest width of the photosensitive film pattern which can be formed by the exposure and development processes.

As described above, the present invention has the effect of forming a wiring width of 3 μm or less (1 to 3 μm) while using existing masks and exposure equipment. In addition, the distance between the wirings may be formed to 3 μm or less (1 to 3 μm).

The wiring forming process can be applied to the pixel electrode and the common electrode forming process of the liquid crystal display as it is.

When the width of the pixel electrode and the common electrode of the liquid crystal display device is narrow, the transmittance is increased, low power driving is possible, and the area occupied by the electrode in the pixel area is reduced, thereby improving the aperture ratio.

2 is a pixel structure of a liquid crystal display device according to a second embodiment of the present invention.

Referring to FIG. 2, a gate area 221 and a data line 203 are alternately arranged on a substrate to define a pixel area, and the pixel electrode 240 and the common electrode 250 are alternately disposed in the pixel area. .

The pixel electrode 240 is electrically connected to the drain electrode of the TFT, and the common electrode 250 is electrically connected to the common wiring formed in parallel with the gate wiring 221. The pixel electrode 240 and the common electrode 250 are formed of a transparent conductive material.

In the liquid crystal display having the structure as described above, the transmittance is controlled by rotating the liquid crystal molecules of the liquid crystal layer by a horizontal electric field generated between the pixel electrode 240 and the common electrode 250 formed in the pixel region.

In the present invention, when the common electrode and the pixel electrode are formed on the same layer in the pixel structure of the IPS (In-Plane Switching) or FFS (Fringe Field Switching) mode, the electrodes are formed by applying the wiring forming method of FIGS. 1A to 1E. Form. A detailed description thereof will be described with reference to FIG. 3.

3 is a cross-sectional view taken along line AA ′ of FIG. 2.

Referring to FIG. 2, a metal film is formed on the insulating substrate 200, and a first mask process is performed to form a gate electrode 201, a gate wiring (not shown), or the like. The metal film may be formed of a single metal layer such as copper (Cu), aluminum (Al), molybdenum (Mo), or Cr having high conductivity, and may be formed by laminating at least one of them in some cases.

When the gate electrode 201 is formed on the insulating substrate 200, the gate insulating film 202, an amorphous silicon film, a doped (n + or p +) amorphous silicon film, and a source / drain metal film are sequentially formed. The second mask process is performed. In the second mask process, either a diffraction mask or a halftone mask may be used.

The active layer 204 including the channel layer and the ohmic contact layer of the thin film transistor and the source / drain electrodes 206a and 206b are formed on the gate electrode 201. At this time, the data line 203 is also formed. An active layer 204 is present under the data line 203 depending on the characteristics of a diffraction or halftone mask process.

As described above, when the source / drain electrodes 206a and 206b are formed on the insulating substrate 200, the protective layer 209 is formed, and then a third mask process is performed to perform a contact hole process. In the contact hole process, a part of the drain electrode 206b and a gate pad and a data pad area are exposed, although not shown in the drawing.

Next, after the transparent conductive film is formed on the insulating substrate 200, the fourth mask process is performed to form the pixel electrode 240 and the common electrode 250 in the pixel region. The pixel electrode 240 and the common electrode 250 are alternately formed in the pixel area.

In addition, in the fourth mask process, the pixel electrode 240 and the common electrode 250 are formed by applying the wiring forming process described with reference to FIGS. 1A through 1E.

That is, after the transparent conductive film is formed on the insulating substrate 200, the negative photosensitive film is applied, and the exposure and development processes are performed. Then, the pixel electrode 240 and the common electrode 250 are formed according to the process described with reference to FIGS. 1A to 1E.

As described with reference to FIGS. 1A to 1E, the width of the pixel electrode 240 and the common electrode 250 is 3 μm or less (1 to 3 μm), and the distance between the pixel electrode 240 and the common electrode 250 is shown. It becomes 3 micrometers or less (1-3 micrometers).

1A to 1E illustrate a wiring forming process according to a first embodiment of the present invention.

2 is a pixel structure of a liquid crystal display device according to a second embodiment of the present invention.

3 is a cross-sectional view taken along line AA ′ of FIG. 2.

 (Explanation of reference numerals for the main parts of the drawings)

100: insulating substrate 110: transparent conductive film

200: photoresist pattern 130: metal film

210: first wiring 211: second wiring

Claims (6)

Forming a first metal film on the substrate; Applying a negative photoresist film on the metal film, and performing an exposure and development process to form a photoresist pattern having a reverse taper structure; Forming a second metal film on the substrate on which the photosensitive film pattern is formed; Performing an etching process using the photosensitive film pattern and the second metal film formed on the first metal film as a mask to form a first wiring and a second wiring; Removing the second metal film; And Removing the photoresist pattern. The wiring forming method according to claim 1, wherein the first wiring is formed by the photosensitive film pattern. The wiring forming method according to claim 1, wherein the second wiring is formed by a second metal film formed on the first metal film. The wiring forming method according to claim 1, wherein the first wiring has a width narrower than the width of the lower surface contacting the photosensitive film pattern. The wiring forming method according to claim 1, wherein the second wiring has a width narrower than a width of the second metal film formed on the first metal film. Forming a metal film on the substrate, and then performing a first mask process to form a gate electrode and a gate wiring; A gate insulating film, an amorphous silicon film, a doped amorphous silicon film, and a source / drain metal film are sequentially formed on the substrate on which the gate electrode is formed, and then a second mask process is performed to form source / drain electrodes, active layers, and data lines. Forming; Forming a protective film on the entire surface of the substrate on which the source / drain electrodes and the like are formed, and then performing a third mask process to form contact holes; And Performing a fourth mask process according to claim 1 on the passivation layer; The liquid crystal display device manufacturing method according to claim 1, wherein the first wiring and the second wiring are formed in the pixel region, the first wiring is a pixel electrode, and the second wiring is a common electrode.

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