KR20010048150A - A thin film transistor liquid crystal display device capable of displaying images in both reflective and transmissive modes and a method for manufacturing it - Google Patents

Abstract

PURPOSE: A reflective-transmissive type thin film transistor(TFT) liquid crystal display(LCD) device and a method for fabricating the same are to secure a transmission area maximumly, thereby improving a transmission characteristic. CONSTITUTION: A gate electrode(2) and a gate interconnection(11) are formed on a transparent substrate(1). A gate insulating layer(3) is formed on the gate electrode and the gate interconnection. An active layer is formed on the insulating layer and is patterned to thereby form an active area(4). A transparent conduction layer(5) is formed and patterned to thereby form a source electrode(5a), a pixel electrode transparent layer(12), a drain electrode(5b) and a data interconnection(13). A passivation layer is formed on an entire structure, and a contact hole(9) is formed to expose a predetermined portion of the drain electrode and the pixel electrode transparent layer. A reflective plate(8a) is formed over the passivation layer on which the contact hole is formed.

Description

Reflective-transmissive thin film transistor liquid crystal display device and method for manufacturing the same

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display and a manufacturing method thereof, and more particularly to a thin film transistor liquid crystal display capable of displaying an image in a reflective mode and a transmissive mode. Film Transistor LCD) and a method of manufacturing the same.

Liquid crystal (Liquid Crystal) is a material that can adjust the phase change of the polarization by changing the arrangement by the influence of the electric field (electric field), such as soap material is not a solid material or a liquid in the intermediate state. Since the liquid crystal display (LCD) using the liquid crystal does not emit light by itself, an external light source is required.

In general, in most monochromatic LCD devices used in small electronic calculators and the like, reflecting plates are used to reflect ambient light. Therefore, such LCD devices are referred to as "reflective type devices". On the other hand, back-lights are used in portable computers, LCD TVs, or other color display devices, and these LCD devices are commonly referred to as "transmissive type devices."

In a vehicle or the like, a reflective-transmissive type or semi-transparent type LCD device is used. The device is mainly used in reflective mode when the ambient light is strong enough, or in transmissive mode with back light.

There are two conventional techniques for enabling use in the dark.

The first is a technology of forming a transflective film on the back of the LCD panel. In this technique, the light of the back light passes through the transflective membrane. The transflective film also functions as a reflective film that reflects light in a bright environment. However, when such an LCD display is operated in a reflective mode, a large parallax occurs due to the position of the transflective film, that is, because the transflective film is formed on the outside of the panel, and its reflective characteristic is caused. This problem has greatly fallen.

The second technique is to attach front-lights to reflective LCD panels. In this technology, a light source is placed in front of the panel to make the reflective panel visible in the dark. However, due to the light guide plate used for the front-light, the visibility is degraded because its reflection characteristics are greatly degraded during operation.

Accordingly, the present invention has been made to solve the above-mentioned conventional problems, and a general object of the present invention is to provide a reflection-transmissive liquid crystal display device and a method of manufacturing the same, in which a reflection region and a transmission region coexist in one pixel electrode. It is.

Another object of the present invention is to provide a reflection-transmissive liquid crystal display device having improved reflection and transmission characteristics and a method of manufacturing the same.

It is still another object of the present invention to provide a method of manufacturing a reflection-transmission thin film transistor liquid crystal display in which a reflection region and a transmission region coexist in one pixel electrode using only five masks.

1 is a plan view showing the layout of a preferred embodiment of a reflective-transmissive thin film transistor liquid crystal display device according to the present invention; And

FIG. 2 is a cross-sectional view illustrating a plane cut along the line AA ′ of FIG. 1.

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

1: substrate

2: gate electrode

3: gate insulating film

4: active area

5a: source electrode

5b: drain electrode

6: organic insulating film

7: buffer conductive film

8: reflective film

8a: reflector

9: contact or contact hall

10: thin film transistor liquid crystal display device

11: gate wiring

12: pixel electrode transparent layer

13: data wiring

The thin film transistor liquid crystal display (TFT-LCD) according to the present invention may function mainly as a reflection type in a bright environment such as outdoors, and may function as a transmissive display device mainly using a back light in a dark environment such as indoors. .

The reflective-transmissive TFT-LCD device of the present invention having the above characteristics has a gate pattern including a gate electrode and a gate wiring formed on a transparent substrate, a gate insulating film stacked over the gate pattern, and the gate electrode via the gate insulating film. A semiconductor active pattern formed over the active pattern, a source / drain electrode formed over the active pattern, a transparent layer for data lines and pixel electrodes, a hole formed over the transparent conductive layer and formed over a portion of the drain electrode or the pixel electrode transparent layer. And a pixel electrode reflector formed on the passivation layer and connected to the drain electrode or the pixel electrode transparent layer through the hole.

In this case, if the transparent conductive film forming the drain electrode or the pixel electrode transparent layer is an indium oxide compound, in particular, ITO, aluminum forming a reflective layer, or an insulating aluminum oxide may be formed when it is in contact with the aluminum alloy layer. And a buffer conductive film such as tungsten molybdenum alloy is preferably formed in a double layer.

And the method of manufacturing the reflection-transmissive TFT LCD device of the present invention is as follows. First, a gate electrode and a gate wiring of a transistor used as a switching element of a pixel cell are formed on an insulating substrate. Subsequently, a gate insulating film is formed, a semiconductor film is deposited on the insulating film, and an active region is formed by patterning the semiconductor film. Next, a transparent conductive film is formed on the substrate on which the active region is formed. By patterning the transparent conductive film, a source electrode, a pixel electrode transparent layer, a drain electrode, and a data wiring are formed. At this time, one of ITO and IZO is usually used as the transparent conductive film. Subsequently, a protective film such as an organic insulating film is formed on the substrate, and contact holes are formed so that a part of the surface of the drain electrode or the pixel electrode transparent layer is exposed. Next, a reflective plate electrically connected to the drain electrode or the pixel electrode transparent layer is formed on the organic insulating layer through the contact hole. Preferably, the reflective plate is composed of a buffer conductive film and a double layer of a reflective film, and the buffer conductive film is usually formed by one of chromium (Cr) and molybdenum tungsten (MoW), and the reflective film is mainly made of one of aluminum and aluminum alloy. Is formed by. The buffer conductive film serves as a buffer film for preventing the Al reflecting film from reacting with a material in the transparent pixel region, that is, ITO or IZO.

As described above, the reflective-transmissive TFT-LCD according to the present invention is an audio-video device such as a still camera requiring low power consumption, hand-held personal computers, and high It can be usefully used in a vehicle or the like for which visibility is required.

(Example)

Next, the structure of the LCD device and the manufacturing method thereof according to the preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a plan view showing the layout of a preferred embodiment of the reflective-transmissive TFT-LCD device 10 according to the present invention, and FIG. 2 shows the AA 'line in the reflective-transmissive TFT-LCD device 10 shown in FIG. This is a cross-sectional view showing the unfolded surface cut along.

Referring to FIGS. 1 and 2, first, a metal film such as chromium (Cr), aluminum (Al), a double layer of chromium and aluminum, and tantalum (Ta) is formed on a transparent insulating substrate 1 such as glass. After forming the film (preferably about 2000) in thickness, the gate electrode 2 and the gate wiring 11 of the thin film transistor are patterned using a gate mask. The transistor is used as a switching element of a pixel cell.

Next, a gate insulating film 3 such as a silicon nitride film (SiN _x ), a silicon oxide film (SiO _x ), or the like is formed on the entire surface of the substrate on which the gate electrode 2 is formed, and has a thickness of about 2000 GPa, and the insulating film 3 ) Is deposited on an amorphous silicon layer 2000 to 3000 으로서 as an active layer and an amorphous silicon layer doped with a high concentration of impurities (n ⁺ ) as an ohmic contact layer. Then, the active region 4 is obtained by patterning the ohmic contact layer and the active layer using an active mask.

Next, a transparent conductive film 5 such as indium tin oxide (ITO), indium zinc oxide (IZO), or the like is formed on the substrate to a thickness of about 500 to 3000 Pa, and then a source / drain ( The source electrode 5a, the pixel electrode transparent layer 12, the drain electrode 5b, and the data wiring 13 are formed using a drain mask. At this time, after the transparent conductive film is etched, the ohmic contact layer is also etched away from the source / drain to form a channel of the transistor. The pixel electrode transparent layer 12 is electrically connected to the drain electrode and is formed to include at least the transparent region of the pixel portion. In the present invention, the source electrode 5a, the pixel electrode transparent layer 12, the drain electrode 5b, and the data wiring 13 are formed using the transparent conductive film 5, so that the source / drain regions are reduced in order to reduce the wiring resistance. It is desirable to design as broadly as possible, and the use is preferably limited to the small screen LCD.

On the substrate on which the source / drain electrodes are formed, an organic insulating film 6 such as acryl-based or the like is formed to a thickness of about 1 to 3 μm. By appropriately adjusting the thickness of the organic insulating film 6, the reflective and transmissive characteristics can be adjusted.

Subsequently, after planarizing the surface of the organic insulating layer 6, a portion of the pixel electrode transparent layer 12 is formed by partially removing the organic insulating layer 6 by performing an exposure process using a contact mask. The contact hole 9 is formed so that the surface is exposed. In this case, when the formation of a lens for condensation is required, a bend for lens function is formed on the upper surface of the organic insulating layer 6 by using a contact and a lens mask (1 mask) or a contact mask and a lens mask (2 masks). You may.

Next, a buffer conductive film 7 electrically connected to the pixel electrode transparent layer through the contact hole 9 is deposited on the organic insulating layer 6 to a thickness of about 1000 mW, and then a reflective film 8 is deposited thereon. Form thinly.

Finally, the reflective plate 8a is formed by patterning the buffer conductive film 7 and the reflective film 8 using a reflective plate mask. The reflecting plate 8a forms a reflective region of the pixel portion as part of the pixel electrode, and is electrically connected to the drain electrode 5b through the pixel electrode transparent layer 12. As the buffer conductive film 7, chromium (Cr) or molybdenum tungsten (MoW) is used, and as the reflecting film 8, aluminum, an aluminum alloy, or the like is used. The buffer conductive film 7 serves as a buffer film to prevent the aluminum film used as the reflective plate 8a from reacting with a material (ie, ITO and IZO) in the transparent pixel region.

In manufacturing the reflection-transmissive TFT-LCD device according to the present invention described above, by adjusting the thickness of the organic insulating film appropriately, the reflection characteristics and the transmission characteristics can be adjusted, and the ratio of the area between the reflection region and the transmission region can be adjusted. It will be appreciated that the reflective and transmissive properties can be adjusted by appropriate adjustments.

According to the present invention as described above, when the transparent conductive film is used as the source / drain electrodes, it is possible to maximize the area of the transmission area in the pixel area of the predetermined area, so that the transmission characteristics are improved, that is, excellent reflection-transmissive color of visibility. A liquid crystal display device can be obtained. Further, according to the present invention, it is possible to manufacture a reflection-transmissive thin film transistor liquid crystal display in which a reflection region and a transmission region coexist in one pixel region using only five masks.

Claims (8)

In the method for manufacturing a thin film transistor liquid crystal display device which can display an image in a reflection type and a transmission type at the same time: Forming a gate electrode and a gate wiring on the transparent substrate; Forming a gate insulating film over the gate electrode and the gate wiring; Forming an active region by stacking and patterning an active layer on the insulating film; Stacking a transparent conductive film on the substrate, and forming a source electrode, a pixel electrode transparent layer, a drain electrode, and a data wiring through patterning; Forming a contact hole so that a part of the drain electrode or the pixel electrode transparent layer is exposed after laminating a protective film on the substrate; And forming a reflecting plate over the passivation layer on which the contact hole is formed. The method of claim 1, Forming an ohmic contact layer prior to stacking the semiconductor layer and patterning the active region; And etching the ohmic contact layer in the active region using the source / drain electrodes as an etch mask. The method of claim 2, The transparent conductive film is formed of an indium oxide compound, The reflective plate may be formed by sequentially stacking and patterning a buffer conductive film and a reflective film, wherein the reflective-transmissive thin film transistor liquid crystal display device is manufactured. The method of claim 3, wherein The buffer conductive film is formed of chromium (Cr) or molybdenum tungsten (MoW), and the reflecting film is formed of aluminum or an aluminum alloy, the method of manufacturing a reflection-transmissive thin film transistor liquid crystal display device. A gate pattern comprising a gate electrode and a gate wiring formed on a transparent substrate, A gate insulating layer stacked on the gate pattern; A semiconductor active pattern formed over the gate electrode via the gate insulating layer, A source / drain electrode, a data line and a pixel electrode transparent layer formed on the active pattern and formed of a transparent conductive film; A passivation layer formed over the transparent conductive layer and having a hole on a portion of the drain electrode or the transparent layer of the pixel electrode; And a reflective plate formed over the passivation layer and connected to the drain electrode or the transparent layer of the pixel electrode through the hole. The method of claim 5, And an ohmic contact layer between the active pattern and the source / drain electrodes. The method of claim 6, The reflective plate is a reflection-transmissive thin film transistor liquid crystal display, characterized in that the reflective film is formed on the buffer conductive layer overlapping. The method of claim 7, wherein The buffer conductive layer is made of chromium (Cr) or molybdenum tungsten (MoW).