KR20070072204A - Liquid crystal display device and method for fabricating liquid crystal dispaly device - Google Patents

Abstract

An LCD(Liquid Crystal Display) and a manufacturing method thereof are provided to manufacture the LCD of FFS(Fringe Field Switching mode) with three masks through three mask processes. A gate pattern and a common electrode(103b) are formed on a substrate. A TFT(Thin Film Transistor) is formed on the substrate including the gate pattern. A passivation layer is formed on the entire of the substrate. A drain contact hole and an opening portion are formed on the passivation layer. A pixel electrode(113a) is formed within the drain contact hole and the opening portion of the passivation layer and a common electrode(117) is formed on the upper portion of the passivation layer. The TFT formation process includes processes for forming a gate insulating layer and source/drain electrodes. The opening portion is located at a pixel electrode member.

Description

Liquid crystal display device and manufacturing method {LIQUID CRYSTAL DISPLAY DEVICE AND METHOD FOR FABRICATING LIQUID CRYSTAL DISPALY DEVICE}

1A to 1E are cross-sectional views illustrating a method of manufacturing a liquid crystal display device according to the related art.

2A to 2E are process cross-sectional views illustrating a method of manufacturing a liquid crystal display device according to the present invention, showing process cross-sectional views taken along lines IIIA-IIIA and IIIB-IIIB.

********** Description of the symbols for the main parts of the drawings ************

101: first substrate 103: gate wiring

103a: gate electrode 103b: common electrode

105: gate insulating film 107: active layer

109a: source electrode 109b: drain electrode

111: protective layer 113: transparent conductive layer

113a: pixel electrode 115: photosensitive film 117: common electrode

The present invention relates to a method for manufacturing a liquid crystal display device, and more particularly, to a method for manufacturing a liquid crystal display device capable of reducing a mask process in manufacturing a liquid crystal display device.

Liquid crystal display devices (hereinafter referred to as LCDs) have characteristics such as light weight, thinness, and low power consumption, so that they can be used for terminals or video devices of various information devices in place of cathode ray tubes (CRT). It is used. In particular, the TFT-LCD equipped with the thin film transistor has excellent response characteristics and is suitable for high pixel numbers, thereby realizing high quality and large display devices.

In such a flat panel display, an active element such as a thin film transistor is provided in each pixel to drive a display element. The driving method of the display element of this type is often referred to as an active matrix driving method. .

In the active matrix method, the active elements are arranged in each pixel arranged in a matrix to drive the pixel.

The general active matrix liquid crystal display device is described as follows.

Although not shown in the drawings, each pixel of a thin film transistor liquid crystal display device having N × M pixels arranged vertically and horizontally has a gate line (not shown) and an image signal to which a scan signal is applied from an external driving circuit. It includes a data line (a thin film transistor (not shown) formed in the intersection region of the not shown 2) to be applied.

The thin film transistor (not shown) may include a gate electrode (not shown) branched from a gate line (not shown), a source electrode (not shown) branched from a signal line, and a drain electrode connected to a pixel electrode (not shown). And a semiconductor layer (not shown) formed between the source electrode (not shown) and the drain electrode (not shown).

In addition, when the voltage is applied to the gate electrode (not shown) through the gate line, the thin film transistor (not shown) receives a data voltage applied to the source electrode (not shown) through the data line (not shown). It serves to apply to the drain electrode (not shown) through the semiconductor channel layer (not shown).

When a data voltage is applied to the drain electrode, a voltage difference is generated between the pixel electrode and the common electrode (not shown) of the pixel by applying the data voltage to the pixel electrode connected to the data electrode. Then, due to the voltage difference, the molecular arrangement of the liquid crystal (not shown) existing between the pixel electrode and the common electrode (not shown) is changed. As the molecular arrangement of the liquid crystal is changed, the light transmittance of the pixel is changed.

In this way, a visual difference occurs between the pixel to which the data voltage is applied and the pixel to which the data voltage is not applied.

Accordingly, the liquid crystal display device serves as a display device by collecting pixels having such visual differences.

On the other hand, TFT-LCD has a disadvantage of narrow viewing angle because it adopts TN (Twisted Nematic) driving mode, but recently In Plane Switching (hereinafter referred to as IPS) liquid crystal display device It has been proposed to solve the narrow viewing angle problem to some extent.

However, even though the IPS-LCD realizes a wide viewing angle, a fringe field switching (FFS) liquid crystal display has been proposed to improve low aperture ratio and transmittance.

A general liquid crystal display device manufacturing method of the FFS mode will be described with reference to FIGS. 1A to 1E as follows.

1A to 1E are cross-sectional views illustrating a method of manufacturing a liquid crystal display device according to the related art.

Referring to FIG. 1A, a common electrode 13 is formed by depositing ITO, which is a transparent material, on a substrate 11 and selectively etching the same after exposure and development by a first mask process using a photolithography process technology. .

Next, referring to FIG. 1B, the metal material layer is etched through exposure and development by a second mask process using a photolithography process technology after laminating a metal material on the substrate 11 to etch the gate electrode 15a. Form. In this case, the storage node electrode 15b, the gate pad part 15c, and the data pad part 15d are also formed when the metal material layer is etched.

Subsequently, referring to FIG. 1C, the gate insulating layer 17, the active layer 19, and the metal conductive layer are sequentially stacked over the entire substrate, followed by exposure and development by a third mask process using a diffraction exposure mask. The metal conductive layer and the active layer are sequentially etched to simultaneously form the active layer pattern 19, the source electrode 21a, and the drain electrode 21b.

Next, referring to FIG. 1D, after forming the protective layer 23 over the entire substrate 11, the protective layer 23 is selectively etched by a fourth mask process to expose the drain electrode 21b. Contact holes 25a are formed. In this case, openings 25b and 25c exposing the gate pad part 15c and the data pad part 15d together with the contact hole 25a are formed when the protective layer 23 is etched.

Subsequently, referring to FIG. 1E, after depositing ITO, which is a transparent conductive material, on the entire substrate including the contact hole 25a, the transparent conductive layer is selectively etched through exposure and development by a fifth mask process to thereby drain the drain electrode. The pixel electrode 27a electrically connected to the 21b is formed. In this case, the gate pad 27b and the data pad connected to the gate pad part 15c and the data pad part 15d through the openings 25b and 25c together with the pixel electrode 27a during the etching of the transparent conductive layer. 27c) is also formed.

However, as described above, the liquid crystal display device manufacturing method according to the prior art has the following problems.

According to the liquid crystal display device manufacturing method according to the prior art, the first mask process for forming the common electrode, the second mask process for forming the gate electrode, the third mask process for forming the active layer and the source / drain electrode, At least five mask processes, such as a fourth mask process for forming contact holes and a fifth mask process for forming pixel electrodes, are required to connect the drain electrodes.

Therefore, there is a problem in that the manufacturing process is complicated because the mask process is required at least five times during the device manufacturing as described above, thereby increasing the manufacturing cost.

Accordingly, an object of the present invention is to provide a liquid crystal display device manufacturing method which can simplify the manufacturing process and reduce the manufacturing cost by reducing the number of mask processes during device manufacturing. have.

According to an aspect of the present invention, there is provided a method of manufacturing a liquid crystal display device, including: forming a gate pattern and a common electrode on a substrate; Forming a thin film transistor on the substrate including the gate pattern; Forming a protective film on the entire substrate; Forming a drain contact hole and an opening in the passivation layer; And forming a pixel electrode in the drain contact hole and the opening of the passivation layer, and forming a common electrode on the passivation layer.

In addition, the liquid crystal display device manufacturing method according to the present invention for achieving the above object comprises the steps of forming a gate pattern and a common electrode on the first substrate; Forming a gate insulating layer, an active layer, and a source / drain electrode on the first substrate including the gate pattern; Forming a protective film on the entire first substrate; Forming a drain contact hole and an opening in the passivation layer; Forming a pixel electrode in the drain contact hole and the opening of the passivation layer, and forming a common electrode on the passivation layer; Forming a black matrix and color filter layer on the second substrate; Bonding the second substrate and the first substrate to each other; And forming a liquid crystal layer between the first substrate and the second substrate.

Hereinafter, a method of manufacturing a liquid crystal display device according to the present invention will be described in detail with reference to the accompanying drawings.

2A to 2E are process cross-sectional views showing a method of manufacturing a liquid crystal display device according to the present invention, showing the device layout diagrams and the process cross-sectional views taken along lines IIA-IIA and IIB-IIB.

As shown in FIG. 2A, a gate forming metal material is deposited on a substrate 101 including a TFT region and a pixel region, and then a first photosensitive film (not shown) is coated on the gate metal material layer.

Subsequently, in a state in which a first mask (not shown) is positioned on the first photoresist film (not shown) as a first mask process, light such as ultraviolet light is irradiated, and then a development process is performed to perform the gate wiring area. And a first photoresist pattern (not shown) blocking the common electrode region.

Subsequently, the metal conductive layer (not shown) is selectively etched using the first photoresist pattern (not shown) as a mask to form a gate electrode 103a and a common electrode 103b. At this time, the gate wiring 103 and the gate pad 103b are also formed together when the gate electrode 103a is formed.

Next, as shown in FIG. 2B, an insulating material such as nitride is deposited on the entire substrate including the gate electrode 103a and the common electrode 103b to form a gate insulating film 105 thereon. The active layer 107 and the metal conductive layer 109 are stacked in this order.

Subsequently, after the second photoresist film (not shown) is applied to the entire substrate 101, light such as ultraviolet light is irradiated in a state in which a second mask for diffraction exposure is placed on the second photoresist film by a second mask process. Subsequently, the development process is performed to form a second photoresist pattern (not shown).

Subsequently, the metal conductive layer 109 and the active layer 107 are patterned using the second photoresist pattern (not shown) as a mask.

Subsequently, an ashing process is performed to remove the photoresist pattern portion located on the channel portion of the active layer 107 so that the metal conductive layer 109 is exposed, and then the second photoresist pattern (not shown) is used as a mask. A portion of the metal conductive layer 109 is selectively etched to form a source electrode 109a and a drain electrode 109b.

Subsequently, as shown in FIG. 2C, after removing the second photoresist layer pattern (not shown), the protective layer 111 is deposited on the entire substrate 101, and then a third photoresist layer (not shown) is applied thereon.

Subsequently, in a state in which the second mask is positioned on the third photoresist film in a third mask process, light such as ultraviolet light is irradiated, and then a development process is performed to form a third photoresist film pattern (not shown).

Subsequently, the protective layer 111 is selectively removed using the third photoresist pattern (not shown) as a mask to form a contact hole 111a exposing the drain electrode 109b. In this case, an opening in which a plurality of pixel electrodes are formed when the protective layer 111 is etched is also formed.

Next, after removing the third photoresist pattern (not shown), a transparent conductive layer 113 made of a transparent material such as ITO is deposited on the entire substrate including the opening (not shown) of the contact hole 111a, and then a fourth layer thereon is formed thereon. The photosensitive film 115 is applied.

Subsequently, as illustrated in FIG. 2D, the fourth photoresist film 115 is subjected to ashing so that the upper portion of the transparent conductive layer 113 is exposed. At this time, during the ashing process, the fourth photoresist film 115 remains only in the contact hole 111a and the opening.

Next, as shown in FIG. 2E, the pixel electrode 113a which is electrically connected to the drain electrode 109b by removing the exposed portion of the transparent conductive layer 113 and the pixel electrode present in the opening (not shown) 113a).

Subsequently, a transparent conductive layer (not shown) made of a transparent material such as ITO is deposited on the entire substrate including the remaining fourth photoresist pattern 115a and the passivation layer 111, and then, the lift-off method is performed. The photoresist pattern 115a is removed to form a common electrode 117 on the protective layer 111. In this case, the common electrode 117 does not overlap the pixel electrode 113a.

Although not shown in the drawings, other layers other than the black matrix, the color filter layer, and the overcoat layer may be selectively formed on the upper substrate (not shown).

Then, after the upper substrate is bonded to the lower substrate, a liquid crystal layer (not shown) is formed between the upper substrate and the lower substrate, thereby completing the liquid crystal display device.

As described above, the liquid crystal display device manufacturing method according to the present invention has the following effects.

According to the liquid crystal display device manufacturing method according to the present invention, a first mask process for forming a gate electrode and a common electrode, a second mask process for forming an active layer and a source / drain electrode, and for forming a contact hole Through the third mask process, a liquid crystal display device having three masks of FFS (Fringe Field Switching mode) can be manufactured. In particular, the pixel electrode and the common electrode may be formed using the contact hole filling effect and the lift off after the formation of the protective layer pattern up to the pixel electrode part.

Therefore, although the device was manufactured by at least five mask processes, the device can be manufactured through the mask process three times in the present invention, and thus the number of masks can be reduced, thereby reducing the manufacturing time. It can shorten and reduce manufacturing cost.

Therefore, the liquid crystal display device manufacturing method applied in the present invention can be applied to the manufacturing of the liquid crystal display device of the TN mode, IPS mode and FFS mode.

Claims (18)

Forming a gate pattern and a common electrode on the substrate; Forming a thin film transistor on the substrate including the gate pattern; Forming a protective film on the entire substrate; Forming a drain contact hole and an opening in the passivation layer; And And forming a pixel electrode in the drain contact hole and the opening of the passivation layer, and forming a common electrode on the passivation layer. The method of claim 1, wherein the forming of the thin film transistor comprises forming a gate insulating layer, an active layer, and a source / drain electrode. The method of claim 2, wherein the forming of the active layer and the source / drain electrodes comprises: Sequentially stacking an active layer and a conductive layer on the gate insulating film; Forming a photoresist pattern on the conductive layer by exposing and developing the photoresist by a diffraction exposure process using a diffraction exposure mask; And selectively removing the active layer and the conductive layer using the photoresist pattern as a mask to define the active layer pattern and the source / drain electrodes. The method of claim 3, wherein the diffraction exposure step, Applying a photoresist film on the conductive layer and then placing a diffraction mask on it; And forming a photosensitive film pattern by performing an exposure and development process using the diffraction exposure mask. 5. The method of claim 4, wherein the photosensitive film pattern is subjected to an ashing process so that a portion of the conductive layer positioned on the channel portion is exposed. 6. The method of claim 5, further comprising forming a source / drain electrode by removing a portion of the conductive layer positioned on the channel portion using the remaining photoresist pattern as a mask. The method of claim 1, wherein the opening is positioned in the pixel electrode part. The method of claim 1, wherein the pixel electrode is formed in the drain contact hole and the opening of the passivation layer, and the common electrode is formed on the passivation layer. Forming a transparent conductive layer on a protective film including a drain contact hole and an opening of the protective film, applying a photosensitive film on the transparent conductive layer, etching the photosensitive film until the transparent conductive layer is exposed, and forming a protective film on the protective film And forming a pixel electrode and a common electrode by removing the remaining photosensitive film and the portion of the transparent conductive layer formed on the photosensitive film. The method of claim 8, wherein the removing of the photosensitive film to expose the conductive layer is performed by an ashing process. Forming a gate pattern and a common electrode on the first substrate; Forming a gate insulating layer, an active layer, and a source / drain electrode on the first substrate including the gate pattern; Forming a protective film on the entire first substrate; Forming a drain contact hole and an opening in the passivation layer; And Forming a pixel electrode in the drain contact hole and the opening of the passivation layer, and forming a common electrode on the passivation layer Forming a black matrix and color filter layer on the second substrate; Bonding the second substrate and the first substrate to each other; And And forming a liquid crystal layer between the first substrate and the second substrate. The method of claim 10, wherein the forming of the thin film transistor comprises forming a gate insulating layer, an active layer, and a source / drain electrode. The method of claim 11, wherein the forming of the active layer and the source / drain electrodes comprises: Sequentially stacking an active layer and a conductive layer on the gate insulating film; Forming a photoresist pattern on the conductive layer by exposing and developing the photoresist by a diffraction exposure process using a diffraction exposure mask; And selectively removing the active layer and the conductive layer by using the photoresist pattern as a mask to define the active layer pattern and the source / drain electrodes. The method of claim 12, wherein the diffraction exposure step, Applying a photoresist film on the conductive layer and then placing a diffraction mask on it; And forming a photosensitive film pattern by performing an exposure and development process using the diffraction exposure mask. 15. The method of claim 13, wherein the photosensitive film pattern is subjected to an ashing process so that a portion of the conductive layer positioned on the channel portion is exposed. The method of claim 13, further comprising forming a source / drain electrode by removing a portion of the conductive layer positioned on the channel portion using the remaining photoresist pattern as a mask. The method of claim 10, wherein the opening is positioned in the pixel electrode part. The method of claim 10, wherein the pixel electrode is formed in the drain contact hole and the opening of the passivation layer, and the common electrode is formed on the passivation layer. Forming a transparent conductive layer on a protective film including a drain contact hole and an opening of the protective film, applying a photosensitive film on the transparent conductive layer, etching the photosensitive film until the transparent conductive layer is exposed, and forming a protective film on the protective film And forming a pixel electrode and a common electrode by removing the remaining photosensitive film and the portion of the transparent conductive layer formed on the photosensitive film. The method of claim 10, wherein selectively removing the photosensitive film to expose the conductive layer is performed through an ashing process.

Images