KR20040061501A - Liquid Crystal Display Device and the Method of Manufacturing the Same - Google Patents

Abstract

PURPOSE: An LCD device is provided to increase an available area by forming concavo-convex portions in each layer, in order to magnify a capacitance value, thereby maintaining a voltage maintenance rate for more than a predetermined time by increasing capacitance as improving an opening ratio. CONSTITUTION: A semiconductor layer(22) has plural open areas in a predetermined area of a substrate(21). A gate insulating film(23) is formed on a front side along the open areas of the semiconductor layer(22) to be in the same thickness. Gate lines are formed in predetermined areas of the gate insulating film(23). An interlayer insulating film(25) is formed on a front side of the gate insulating film(23) including the gate lines. Data lines(26) are formed in predetermined areas of the interlayer insulating film(25). Contact layers(26a) are formed between the semiconductor layer(22) and the data lines(26).

Description

Liquid crystal display device and the method of manufacturing the same

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device and a method of manufacturing the same, wherein the patterned layer has irregularities to increase an effective area to improve capacity.

As the information society develops, the demand for display devices is increasing in various forms, and in recent years, liquid crystal display devices (LCDs), plasma display panels (PDPs), electro luminescent displays (ELD), and vacuum fluorescent (VFD) Various flat panel display devices such as displays have been studied, and some of them are already used as display devices in various devices.

Among them, LCD is the most widely used as the substitute for CRT (Cathode Ray Tube) for mobile image display device because of its excellent image quality, light weight, thinness, and low power consumption. In addition to the use of the present invention has been developed in various ways such as a television and a computer monitor for receiving and displaying broadcast signals.

In order to use such a liquid crystal display as a general screen display device in various parts, it is a matter of how high quality images such as high definition, high brightness and large area can be realized while maintaining the characteristics of light weight, thinness and low power consumption. Can be.

A general liquid crystal display device may be largely divided into a liquid crystal panel displaying an image and a driving unit for applying a driving signal to the liquid crystal panel, wherein the liquid crystal panel includes first and second glass substrates bonded to each other with a predetermined space; It consists of a liquid crystal layer injected between the said 1st, 2nd glass substrate.

Here, the first glass substrate (TFT array substrate) has a plurality of gate lines arranged in one direction at regular intervals, a plurality of data lines arranged at regular intervals in a direction perpendicular to the gate lines, A plurality of pixel electrodes formed in a matrix form in each pixel region defined by crossing a gate line and a data line, and a plurality of thin film transistors switched by signals of the gate line to transfer the signal of the data line to each pixel electrode. Is formed.

In the second glass substrate (color filter array substrate), a light shielding layer for blocking light in portions other than the pixel region, an R, G, and B color filter layer for expressing color colors are common to implement an image. An electrode is formed.

The driving principle of the general liquid crystal display device uses the optical anisotropy and polarization property of the liquid crystal. Since the liquid crystal is thin and long in structure, the liquid crystal has directivity in the arrangement of molecules, and the direction of the arrangement of molecules can be controlled by artificially applying an electric field to the liquid crystal.

Therefore, when the molecular arrangement direction of the liquid crystal is arbitrarily adjusted, the molecular arrangement of the liquid crystal is changed, and light is refracted in the molecular arrangement direction of the liquid crystal by optical anisotropy, thereby representing image information.

Currently, an active matrix LCD, in which a thin film transistor and pixel electrodes connected to the thin film transistor are arranged in a matrix manner, is attracting the most attention due to its excellent resolution and ability to implement video.

In an active matrix thin film transistor liquid crystal display (TFT LCD), an electrode of an individual pixel forming a screen of a display device is controlled using a transistor. In this case, the transistor is formed on a substrate using a semiconductor thin film.

The thin film transistor liquid crystal display (TFT LCD) may be roughly divided into an amorphous silicon type and a polysilicon type according to the characteristics of the semiconductor thin film used.

In both cases, efforts are being made to reduce the number of exposure steps in the process in order to reduce the process cost and increase the yield. In the case of amorphous silicon, it is formed by using chemical vapor deposition (CVD) at low temperature. In this case, there is an advantage in the characteristics of the liquid crystal display device using the glass substrate.

However, in the case of amorphous silicon, the carrier mobility is low, and therefore, it is not suitable for forming a transistor element of a driving circuit requiring fast operating characteristics. This fact means that the IC for driving the liquid crystal display device must be manufactured separately and attached to the periphery of the liquid crystal panel, and the manufacturing cost of the liquid crystal display device is increased by adding a process for the driving module.

On the other hand, since polysilicon has a much higher carrier mobility than amorphous silicon, it can be used to manufacture an IC for a driving circuit. Therefore, when polysilicon is used as a semiconductor thin film for forming a thin film transistor of a liquid crystal display device, a thin film transistor element for a pixel electrode and a transistor element for a driving circuit can be formed together on a same glass substrate through a series of processes.

This may reduce the cost of the module process in manufacturing the liquid crystal display and at the same time reduce the power consumption of the liquid crystal display.

Hereinafter, a liquid crystal display according to the related art will be described with reference to the accompanying drawings.

The liquid crystal display device described below relates to a polysilicon liquid crystal display device which forms a semiconductor layer from polysilicon.

1 is a cross-sectional view illustrating a thin film transistor of a general liquid crystal display.

As shown in FIG. 1, a thin film transistor of a general liquid crystal display device includes a semiconductor layer 13 formed in a predetermined region on a substrate 11 and a gate insulating layer 14 formed on the substrate 11 including the semiconductor layer 13. ), A gate electrode 15a formed in a predetermined region on the gate insulating film 14, an interlayer insulating film 16 formed on the entire surface of the gate insulating film 14 including the gate electrode 15a, and the gate electrode 15a. And a source / drain electrode 17 connected to both sides of the semiconductor layer 13.

In addition, the source / drain electrodes 17 are connected to the semiconductor layer 13 through the contact layer 17a.

FIG. 2 is a plan view showing a portion where a capacitor of a conventional liquid crystal display is formed, FIG. 3 is a structural cross-sectional view taken along line II ′ of FIG. 2, and FIG. 4 is a structural cross-sectional view taken along line II-II ′ of FIG. 2. .

2 to 4, the capacitor of the conventional liquid crystal display device forms the thin film transistor described above and simultaneously forms the capacitor. The gate line 11 is used as one electrode, and the gate line ( 11 and a second capacitor Cga between the semiconductor layer 13 via the gate insulating film 14, and a second capacitor Gga between the gate line 11 and the data line 17. A third capacitor Cgc is formed between the capacitor Cgd and the gate line 11 and the contact layer 17a through an interlayer insulating film. Therefore, the sum of the capacitances is Ctotal = Cga + Cgd + Cgc.

The total capacitance (Ctotal) is a criterion for evaluating the voltage retention of the liquid crystal layer, the total capacitance value of a predetermined value or more is required to maintain the polarity of the pixel per frame according to the liquid crystal driving method.

However, the conventional liquid crystal display device as described above has the following problems.

When the voltage of the liquid crystal layer needs to be maintained for a predetermined time or more, the sum of the capacitances should be increased. To do this, a gate dielectric or interlayer dielectric, which is a dielectric between the electrodes constituting the capacitor, in the same structure is used as a material having a high dielectric constant, or It is necessary to change the structure of the display device to increase the area of the capacitor or to reduce the gap between the electrodes.

However, the change of the material to a material having a high dielectric constant leads to an increase in cost, and furthermore, such a structural change is limited because the spacing between layers is limited to a minimum value.

The present invention has been made to solve the above problems, and to provide a liquid crystal display device and a method of manufacturing the same by increasing the effective area by patterning so as to have irregularities for each layer, the object thereof.

1 is a cross-sectional view illustrating a thin film transistor of a general liquid crystal display device.

2 is a plan view showing a portion where a capacitor of a conventional liquid crystal display is formed;

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

4 is a cross-sectional view taken along line II-II 'of FIG.

5 is a cross-sectional view illustrating a thin film transistor of a liquid crystal display of the present invention.

6 is a plan view illustrating a portion where a capacitor is formed in the liquid crystal display according to the first exemplary embodiment of the present invention.

FIG. 7 is a cross-sectional view taken along line III-III ′ of FIG. 6.

8 is a cross-sectional view taken along line IV-IV 'of FIG.

9 is a cross-sectional view taken along line VV ′ in FIG.

10 is a plan view illustrating a portion where a capacitor is formed in the liquid crystal display according to the second exemplary embodiment of the present invention.

FIG. 11 is a structural cross-sectional view taken along lines VI to VI ′. FIG.

12 is a cross-sectional view taken along the line of FIG.

13 is a cross-sectional view taken along the line of FIG.

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

21 substrate 22 semiconductor layer

23: gate insulating film 24: gate line

25 interlayer insulating film 26 data line

26a: contact layer

The liquid crystal display of the present invention for achieving the above object is a semiconductor layer formed to have a plurality of open regions in a predetermined region on the substrate, a gate insulating film formed on the entire surface along the plurality of open regions of the semiconductor layer and A gate line formed in a predetermined region on the gate insulating film, an interlayer insulating film formed on an entire surface of the gate insulating film including the gate line, a data line formed in a predetermined region on the interlayer insulating film, and a contact layer between the semiconductor layer and the data line. It is characterized by including the.

The gate line, the interlayer insulating film, and the data line may be formed to have the same thickness in correspondence with the step of the semiconductor layer.

The open area of the plurality of semiconductor layers is preferably in the shape of a surface in which the semiconductor layer is selectively removed so as to have a curved shape therein.

It is preferable that the space | interval between the open areas of the said semiconductor layer is 0.5 micrometer-50 micrometers.

In addition, the liquid crystal display device of the present invention for achieving the object of the present invention is formed to have a plurality of line-type first open area and a second open area across the center of the line-type open area in a predetermined area on the substrate. A semiconductor layer, a gate insulating film formed on the entire surface along the plurality of open regions of the semiconductor layer with the same thickness, a gate line formed on a predetermined region on the gate insulating film, an interlayer insulating film formed on the entire gate insulating film including the gate line, It is characterized in that it comprises a data line formed in a predetermined region on the interlayer insulating film, and a contact layer of the semiconductor layer and the data line.

The gate line, the interlayer insulating film, and the data line may be formed to have the same thickness in correspondence with the step of the semiconductor layer.

The plurality of linear open regions and the second open regions crossing the centers of the linear open regions may have a line shape and a shape in which the semiconductor layer is selectively removed to have a curvature therein. desirable.

The interval between the first open regions of the semiconductor layer is preferably 0.5 μm to 50 μm.

In addition, the liquid crystal display of the present invention for achieving the same object is formed by forming a semiconductor layer having a plurality of open areas in a predetermined region on the substrate, the gate having the same thickness on the entire surface along the plurality of open areas of the semiconductor layer Forming an insulating film, forming a gate line in a predetermined region on the gate insulating film, forming an interlayer insulating film over the gate insulating film including the gate line, and selectively removing the interlayer insulating film and the gate insulating film. After forming the contact layer, forming a data line connected to the contact layer and perpendicular to the gate line, forming a data line in a predetermined region on the interlayer insulating film, and forming the semiconductor layer and data It is characterized by including a contact layer with a line.

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

5 is a cross-sectional view illustrating a thin film transistor of a liquid crystal display of the present invention.

As shown in FIG. 5, a thin film transistor of a general liquid crystal display device includes a semiconductor layer 23 formed in a predetermined region on a substrate 21 and a gate insulating film 24 formed on the substrate 21 including the semiconductor layer 23. ), A gate electrode 25a formed in a predetermined region on the gate insulating film 24, an interlayer insulating film 26 formed on the entire surface of the gate insulating film 24 including the gate electrode 25a, and the gate electrode 25a. The source / drain electrodes 27 are formed to be connected to the semiconductor layers 23 on both sides of the substrate.

In addition, the source / drain electrodes 27 are connected to the semiconductor layer 23 through the contact layer 27a.

6 is a plan view illustrating a portion where a capacitor is formed in the liquid crystal display according to the first exemplary embodiment of the present invention, FIG. 7 is a cross-sectional view taken along line III-III ′ of FIG. 6, and FIG. A cross-sectional view taken along line IV ′ and FIG. 9 is a cross-sectional view taken along line VV ′ of FIG. 6.

As shown in FIG. 6, the liquid crystal display according to the first exemplary embodiment of the present invention deposits an amorphous silicon layer on the entire surface of the substrate 21, dehydrogenates it, and crystallizes it with a laser to form a polysilicon layer. The polysilicon layer is selectively removed to form the semiconductor layer 22 on the predetermined region.

The semiconductor layer 22 may be formed by selectively removing the polysilicon layer through an etching process, and the like, and the process may be performed by removing the contact region with a source / drain electrode (not shown). A plurality of line-shaped open regions (shown in the shape of the substrate 21 exposed in the drawing) are formed at the portion of.

Here, the line-shaped pattern formed in the semiconductor layer 22 is formed by removing the semi-cylindrical grooves, and appears to be linear on the surface, and the semi-circular pattern is formed to be seen toward the substrate on the cross section.

An interval between the plurality of line-shaped open regions is set to 0.5 to 50 µm.

The width s of the plurality of line-shaped open regions is 0.5 µm to 3 µm.

Hereinafter, a manufacturing method of the liquid crystal display according to the first exemplary embodiment of the present invention will be described with reference to FIGS. 7 to 9.

As shown in FIG. 7, the liquid crystal display according to the first exemplary embodiment of the present invention first forms the semiconductor layer 22 on a predetermined region on the substrate 21.

The semiconductor layer 22 is formed by completely depositing amorphous silicon, dehydrogenating it, and then crystallizing it with a laser. The semiconductor layer 22 is formed by selectively removing the polysilicon. At this time, in the process of removing the polysilicon, a process of forming a plurality of line-type open regions spaced at regular intervals is performed at the same time.

Next, a gate insulating film 23 is deposited on the entire surface of the substrate 21 including the semiconductor layer 22.

Subsequently, a gate line 24 is formed in a predetermined region on the gate insulating film 23. The gate line 24 is an electrode of one of the capacitors formed in the liquid crystal display, and the area of the gate line 24 is an important factor in the capacitance.

The interlayer insulating film 25 is entirely deposited on the gate insulating film 23 including the gate line 24.

The interlayer insulating layer 25 and the gate insulating layer 23 are selectively removed to form a contact region with the semiconductor layer 22.

Subsequently, the contact region is filled and a metal layer is deposited on the entire surface of the interlayer insulating layer 25, and then selectively removed to form the data line 26 in a predetermined region.

Here, the metal layer embedded in the contact region functions as the contact layer 26a.

The data line 26 and the gate line 24 are vertically intersected with each other, and the interlayer insulating layer 25 is interposed between the two lines.

The gate insulating layer 23, the gate line 24, the interlayer insulating layer 25, and the data line 25 formed on the semiconductor layer 22 may have a semiconductor layer 22 having irregularities due to the plurality of open regions. (Chemical Vapor Deposition), the deposition process is performed by CVD (Chemical Vapor Deposition). The layers corresponding to the upper and lower layers all have the same unevenness, and the unevenness serves to increase the area of the interface where the two layers meet, thereby increasing the total capacitance of the liquid crystal display.

As described above, the capacitor formed by using the gate line 24 as one electrode and the contact layer and the data line 26 as the remaining electrodes in parallel with the gate line 24 has an increased area where each meets the capacitance. The value will rise.

Meanwhile, since the semiconductor layer 22 is partially removed, the capacitor Cga having the gate line 24 as one electrode and the semiconductor layer 22 as the other electrode may have a smaller value than that of the related art. In general, when the semiconductor layer is not doped, since the depletion of the semiconductor layer occurs and the first capacitance Cga is small, this is not a big problem.

In addition, even when the semiconductor layer 22 is doped, it may be a disadvantage since one more photo mask step needs to be added.

Since the formation of the first capacitance Cga between the semiconductor layer 22 and the gate line 24 according to the first embodiment of the present invention is not a planar form of the conventional structure, but a semi-cylinder form, Since the capacitance can be implemented, the loss resulting from etching the semiconductor layer 22 can be compensated for.

In addition, the second capacitance Cgd formed between the gate line 24 and the data line 26 may be formed at a portion where the gate line 24 having the unevenness and the data line 26 having the unevenness meet. The effective area between the two increases, so that the capacitance value can be increased. Therefore, the capacitance can be increased for the same design, so that the same capacitance can be secured while reducing the design area, thereby increasing the aperture ratio.

In addition, the third capacitance Cgc formed between the gate line 24 and the contact layer 26a may be maintained at the same level as in the prior art.

An interval between the plurality of line-shaped open regions is set to 0.5 to 50 µm.

FIG. 10 is a plan view showing a portion where a capacitor is formed in the liquid crystal display according to the second exemplary embodiment of the present invention, FIG. 11 is a cross-sectional view of the structure of FIGS. VI to VI ', and FIG. 12 is a line of FIGS. It is a structural cross section, and FIG. 13 is a structural cross section along the line of FIG.

As shown in FIG. 10, the liquid crystal display according to the second exemplary embodiment of the present invention deposits an amorphous silicon layer on the entire surface of the substrate 21, dehydrogenates it, and converts polysilicon crystallized by laser into the semiconductor layer 22. The patterning process is performed on a predetermined portion of the semiconductor layer 22, and includes a plurality of line-type first open regions on portions of the semiconductor layer 22 except for contact regions with source / drain electrodes (not shown); And forming a second open area that crosses the center of the line-shaped open area.

Here, the first open region formed in the semiconductor layer is formed by removing the semi-cylindrical grooves in three dimensions, and looks like a line on the surface, and is formed so that the semi-circular pattern enters the substrate side in cross section. In addition, the second open area is formed on the center to cross the first open areas, and the shape is the same as the first open area.

At this time, the second open area is increased as compared with the first embodiment, so that the unevenness of the surface is further increased, and therefore, the capacitance formed between the layers formed on the upper part also obtains a large value.

Hereinafter, a manufacturing method of the liquid crystal display according to the second exemplary embodiment of the present invention will be described with reference to FIGS. 11 to 13.

As shown in FIG. 11, in the liquid crystal display according to the second exemplary embodiment, the semiconductor layer 22 is first formed on the substrate 21 in a predetermined region.

The semiconductor layer 22 is formed by completely depositing amorphous silicon, dehydrogenating it, and then crystallizing it with a laser. The semiconductor layer 22 is formed by selectively removing the polysilicon. At this time, in the process of removing the polysilicon, a process of forming a plurality of linear first open regions spaced at regular intervals and a second open region transverse to the first open region is simultaneously performed.

Next, a gate insulating film 23 is deposited on the entire surface of the substrate 21 including the semiconductor layer 22.

Subsequently, a gate line 24 is formed in a predetermined region on the gate insulating film 23. The gate line 24 is an electrode of one of the capacitors formed in the liquid crystal display, and its area is an important factor for the capacitance.

The interlayer insulating film 25 is entirely deposited on the gate insulating film 23 including the gate line 24.

The interlayer insulating layer 25 and the gate insulating layer 23 are selectively removed to form a contact region with the semiconductor layer 22.

Subsequently, the contact region is filled and a metal layer is deposited on the entire surface of the interlayer insulating layer 25, and then selectively removed to form the data line 26 in a predetermined region.

At this time, the metal layer embedded in the contact region functions as a contact layer 26a.

The data line 26 and the gate line 24 are vertically intersected with each other, and the interlayer insulating layer 25 is interposed between the two lines.

The gate insulating layer 23, the gate line 24, the interlayer insulating layer 25, and the data line 26 formed on the semiconductor layer 22 may have the uneven semiconductor layer 22 due to the plurality of open regions. (Chemical Vapor Deposition), the deposition method is performed by CVD (Chemical Vapor Deposition). The upper and lower layers have the same unevenness, and the unevenness serves to increase the area of the interface where the two layers meet, so that the total capacitance of the liquid crystal display is increased.

As described above, the capacitor formed by using the gate line 22 as one electrode and using the contact layer 26a and the data line 26 as the remaining electrodes in parallel with the gate line 22 increases the area where each meets. Thus, the capacitance value rises.

On the other hand, the capacitor Cga having the gate line 24 as one electrode and the semiconductor layer 22 as the other electrode is partially removed from the semiconductor layer 22, so that the value may be reduced as compared with the related art. In general, when the semiconductor layer 22 is not doped, depletion of the semiconductor layer 22 occurs and the capacitance Cga is small, which is not a big problem.

The liquid crystal display of the present invention as described above and a method of manufacturing the same have the following effects.

First, it is possible to increase the value of capacitance by increasing the effective area by providing irregularities for each floor.

Second, the voltage retention may be maintained for a predetermined time for a predetermined time due to an increase in capacitance.

Third, the effective area of the capacitor can be increased without additional processes, and thus the area of the electrode of the capacitor can be reduced when designing the capacitor, and thus the aperture ratio can be improved.

Claims (9)

A semiconductor layer formed to have a plurality of open regions in a predetermined region on the substrate; A gate insulating film formed on the entire surface of the gate insulating layer along a plurality of open regions of the semiconductor layer; A gate line formed in a predetermined region on the gate insulating film; An interlayer insulating film formed over the entire gate insulating film including the gate line; A data line formed in a predetermined region on the interlayer insulating film; And a contact layer between the semiconductor layer and the data line. The method of claim 1, And the gate line, the interlayer insulating film, and the data line are formed to have the same thickness corresponding to the step of the semiconductor layer. The method of claim 1, The open area of the plurality of semiconductor layers has a line-like surface and a shape in which the semiconductor layer is selectively removed to have a curvature therein. The method of claim 1, The interval between the open regions of the semiconductor layer is a liquid crystal display device, characterized in that 0.5㎛ 50㎛. A semiconductor layer formed to have a plurality of linear open regions and a second open region crossing a center of the linear open region in a predetermined region on the substrate; A gate insulating film formed on the entire surface of the gate insulating layer along a plurality of open regions of the semiconductor layer; A gate line formed in a predetermined region on the gate insulating film; An interlayer insulating film formed over the entire gate insulating film including the gate line; A data line formed in a predetermined region on the interlayer insulating film; And a contact layer between the semiconductor layer and the data line. The method of claim 5, And the gate line, the interlayer insulating film, and the data line are formed to have the same thickness corresponding to the step of the semiconductor layer. The method of claim 5, The plurality of linear open regions and the second open regions crossing the centers of the linear open regions may have a line shape and a shape in which the semiconductor layer is selectively removed to have a curvature therein. A liquid crystal display device characterized by the above-mentioned. The method of claim 1, The interval between the first open region of the semiconductor layer is a liquid crystal display device, characterized in that 0.5㎛ 50㎛. Forming a semiconductor layer to have a plurality of open regions in a predetermined region on the substrate; Forming a gate insulating film on the entire surface of the semiconductor layer along a plurality of open regions of the semiconductor layer; Forming a gate line in a predetermined region on the gate insulating film; Forming an interlayer insulating film on an entire surface of the gate insulating film including the gate line; Forming a contact layer by selectively removing the interlayer insulating film and the gate insulating film, and then forming a data line connected to the contact layer and perpendicular to the gate line; Forming a data line in a predetermined region on the interlayer insulating film; And a contact layer between the semiconductor layer and the data line.