KR100345959B1 - Thin film transistor array panel for liquid crystal display and manufacturing method of the same - Google Patents

Abstract

Forming a gate wiring on the insulating substrate, forming a gate insulating film, a semiconductor layer, a contact layer and a data wiring on the gate wiring, depositing an auxiliary insulating film, applying a photosensitive organic insulating material on the auxiliary insulating film, and exposing and developing the protective insulating film. In the portion where the protrusion is to be formed, there is no thickness in the portion where the contact hole is to be formed, and in the remaining portion, a thin photosensitive organic insulating layer pattern is formed. The photosensitive organic insulating layer pattern is used as an etch mask to form a contact hole by etching the auxiliary insulating layer and the gate insulating layer at the lower portion thereof, and then the thin portion is removed by ashing the photosensitive organic insulating layer pattern to form protrusions and a protective insulating layer. In this case, an opening pattern and protrusions can be formed to secure a wide viewing angle without additional processing at all, compared to a conventional vertical alignment liquid crystal display device, and the common electrode voltage is increased or expensive because the common electrode of the upper panel is not patterned. The problem that an overcoat film should be formed is eliminated. In addition, since the protrusions are formed of the photosensitive organic layer, the height of the protrusions is easily controlled, and the protrusions are formed uniformly with smooth slanting without sharp angles, thereby preventing the domains from being disturbed.

Description

Thin film transistor substrate for liquid crystal display device and manufacturing method therefor {THIN FILM TRANSISTOR ARRAY PANEL FOR LIQUID CRYSTAL DISPLAY AND MANUFACTURING METHOD OF THE SAME}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device and a thin film transistor substrate used therein, and more particularly, to a vertically aligned liquid crystal display device forming an opening pattern and a projection in a pixel electrode, and a thin film transistor substrate used therein.

In general, a liquid crystal display device injects a liquid crystal material between an upper substrate on which a common electrode, a color filter, and the like are formed, and a lower substrate on which a thin film transistor and a pixel electrode are formed. By applying a different potential to form an electric field to change the arrangement of the liquid crystal molecules, and through this to control the light transmittance is a device that represents the image.

However, it is an important disadvantage that the liquid crystal display device has a narrow viewing angle. In order to overcome these disadvantages, various methods for widening the viewing angle have been developed. Among them, liquid crystal molecules are oriented vertically with respect to the upper and lower substrates, and a method of forming a constant opening pattern or forming protrusions on the pixel electrode and the common electrode opposite thereto is performed. This is becoming potent.

In the conventional method of forming the opening pattern, an opening pattern is formed on the pixel electrode and the common electrode, and the viewing angle is widened by adjusting the direction in which the liquid crystal molecules lie down using a fringe field formed by the opening patterns. There is this.

However, in this case, since the common electrode made of indium tin oxide (ITO) formed on the color filter is patterned by using photolithography, a photolithography process is added.

In addition, the adhesion between the ITO deposited on the color filter by sputtering and the color filter resin is not good, so that the precision of the common electrode is inferior. In addition, there is a problem that damage occurs when the color filter is exposed during ITO etching, so to prevent this, a reliable organic insulating (overcoat film) is coated on the color filter (coating), which has a problem that the overcoat film is expensive. When the overcoat layer is formed, the common electrode may not directly contact a black matrix formed of chromium (Cr) or the like, thereby causing a problem such as an increase in resistance and severe flicker defects.

In addition, since an opening pattern is formed in the common electrode, an increase in resistance of the common electrode is increased.

On the other hand, when the upper and lower substrates are aligned, the opening pattern formed on the common electrode of the upper plate and the opening pattern formed on the pixel electrode of the lower plate also have difficulty in accurately aligning.

As shown in FIG. 1, the projection is formed by forming projections 6 and 7 on the pixel electrodes 3 and the common electrode 4 formed on the upper and lower substrates 1 and 2, respectively. It is a method of controlling the lying direction of the liquid crystal molecules by using the electric field distorted by (6, 7).

In this manner, a process of forming protrusions of the upper and lower substrates 1 and 2 has to be added, and thus there is a problem in that the production cost increases and the upper and lower protrusions 6 and 7 must be aligned correctly.

As another method, as shown in FIG. 2, an opening pattern 7 is formed on the pixel electrode 3 formed on the lower substrate 1, and the common electrode 4 formed on the upper substrate 2. The protrusion 6 is formed on the top to form a domain by adjusting the opening pattern 7 and the fringe field formed by the protrusion 6 in the lying direction of the liquid crystal.

In this manner as well, the process of forming the protrusions 6 on the common electrode 4 has to be added, as well as the difficulty of accurately aligning the protrusions 6 and the opening pattern 7 when the upper and lower substrates 1 and 2 are aligned. .

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide a method of forming opening patterns and protrusions for widening a viewing angle without complicating a manufacturing process of a liquid crystal display device.

1 and 2 are cross-sectional views of a liquid crystal display device according to the prior art, respectively,

3 is a layout view of a thin film transistor substrate according to a first exemplary embodiment of the present invention,

4 and 5 are cross-sectional views taken along line IV-IV 'and V-V' of FIG. 3, respectively.

6A is a layout view of a substrate in an intermediate step of a process of manufacturing a thin film transistor substrate according to the first embodiment of the present invention;

6B and 6C are cross-sectional views taken along lines VIb-VIb 'and VIc-VIc' of FIG. 6A, respectively.

FIG. 7A is a layout view of a substrate in the next step of FIGS. 6A-6C,

7B and 7C are cross-sectional views taken along the lines 'b-'b' and 'c-'c' of FIG. 7A, respectively.

8A and 8B are cross-sectional views taken along lines VIIb-VIIb 'and VIIc-VIIC' of FIG. 7A, respectively, to show the photomask and substrate at an intermediate stage from the steps of FIGS. 6A-6C to the steps of FIGS. 7A-7C. Is a drawing showing the alignment state,

9A and 9B are cross-sectional views taken along the lines 'b-'b' and 'c-'c' of FIG. 7A, respectively, and are cross-sectional views of the substrate in the next steps of FIGS. 8A and 8B;

10 is a cross-sectional view of a liquid crystal display device using a thin film transistor substrate according to a first embodiment of the present invention.

11 is a layout view of a thin film transistor substrate according to a second exemplary embodiment of the present invention.

12 and 13 are cross-sectional views taken along lines XII-XII 'and XIII-XIII' of FIG. 11, respectively.

14A is a layout view of a substrate in an intermediate step of a process of manufacturing a thin film transistor substrate according to the first embodiment of the present invention;

14B and 14C are cross-sectional views taken along lines XIVb-XIVb 'and XIVc-XIVc' of FIG. 14A, respectively.

15A and 15B are cross-sectional views taken along lines XIVb-XIVb 'and XIVc-XIVc' of FIG. 14A, respectively, and show a state of alignment between the substrate and the photomask in the previous steps of FIGS. 14A to 14C;

16 is a cross-sectional view of a liquid crystal display using a thin film transistor substrate according to a second embodiment of the present invention.

In order to solve this problem, the present invention simultaneously forms a protective insulating film using a photosensitive organic insulating material, or simultaneously forms a projection and a pixel electrode using a photosensitive film for forming a pixel electrode.

Specifically, forming a gate wiring including a gate line, a gate pad connected to the gate line, and a gate electrode that is part of the gate line on an insulating substrate, a gate insulating film, a semiconductor layer, a contact layer, and data on the gate wiring. Forming a data line including a line, a source electrode connected to the data line, a drain electrode facing the source electrode, and a data pad connected to one end of the data line, a protective insulating film made of a photosensitive organic insulating material; A thin film transistor substrate is manufactured by a process including forming a protrusion and forming a pixel electrode connected to the drain electrode and having an opening pattern on the protrusion.

In this case, an auxiliary insulating layer made of an inorganic material may be further formed on the data line before the forming of the protective insulating layer and the protrusion, and exposing the gate pad, the data pad, and the drain electrode, respectively, in the forming of the protective insulating layer and the protrusion. The first to third contact holes may be formed, and the forming of the protective insulating film and the protrusion may include stacking the photosensitive organic insulating film, first and second portions having different light transmittances according to portions of the photosensitive organic insulating film. Exposing through a photomask having a third portion, developing the photosensitive organic insulating film to have a first thickness at the portion where the protective insulating film and the protrusion are to be formed, and having no thickness on the gate pad, the data pad, and the drain electrode; Forming a photosensitive organic insulating layer pattern having a second thickness that is thinner than the first thickness in the portion; Etching the lower insulating film to expose the gate pad, the data pad, and the drain electrode by using the organic insulating film pattern as an etch mask, and removing the portion having the second thickness by ashing the photosensitive organic insulating film pattern to remove only the protective insulating film and the protrusions. It can be done in a step left.

Or forming a gate line on the insulating substrate, the gate line including a gate line, a gate pad connected to the gate line, and a gate electrode that is part of the gate line; A data wiring including a source electrode, a drain electrode facing the source electrode, and a data pad connected to one end of the data line; first to second data lines formed on the data wiring to expose the gate pad, the data pad, and the drain electrode, respectively. A thin film transistor substrate is manufactured by forming a passivation layer having a third contact hole, and forming a protrusion formed on the pixel electrode together with the pixel electrode and formed of a photosensitive material.

In this case, in the forming of the pixel electrode, an auxiliary gate pad and an auxiliary data pad covering the gate pad and the data pad may be formed, respectively, and forming the protrusion together with the pixel electrode may include stacking an ITO layer and an ITO layer. Stacking a photoresist film thereon; exposing the photoresist film through a photomask having a first portion, a second portion, and a third portion, each having a different light transmittance, according to a portion; Forming a photoresist pattern having a thickness, and having a second thickness thinner than a first thickness on the portion where the pixel electrode, the auxiliary gate pad, and the auxiliary data pad are to be formed, and having no thickness on the other portion; forming the photoresist pattern as an etch mask Etching the ITO layer to form a pixel electrode, an auxiliary gate pad, and an auxiliary data pad, and ashing the photoresist pattern Removing the portion having a thickness can be made to leave only the projections.

Next, a structure of a thin film transistor substrate for a liquid crystal display according to an exemplary embodiment of the present invention will be described with reference to the drawings.

3 is a layout view of a thin film transistor substrate according to a first exemplary embodiment of the present invention, and FIGS. 4 and 5 are cross-sectional views taken along lines IV-IV ′ and V-V ′ of FIG. 3, respectively.

First, gate wirings and sustain electrode wirings made of metal such as aluminum or aluminum alloy are formed on the insulating substrate 10. The gate line is connected to the gate line 22 and the end of the gate line 22 extending in the horizontal direction and is a part of the gate pad 24 and the gate line 22 which receive a gate signal from the outside and transfer the gate signal to the gate line. The gate electrode 26 of the thin film transistor is included, and the storage electrode wiring includes a storage electrode line 27 extending in the horizontal direction and a storage electrode pad 28 connected to the end of the storage electrode line 27. At this time, the gate wirings 22, 24, 26 and the sustain electrode wirings 27, 28 may be formed as a single layer, but may be formed as a double layer or a triple layer. In the case of forming a single layer, it is made of aluminum (Al) or aluminum (Al) -neodymium (Nd) alloy. In case of forming a double layer, the lower layer is made of aluminum (Al) -neodymium (Nd) alloy, and the upper layer is made of molybdenum ( Mo) -tungsten (W) alloy can be made.

A gate insulating layer 30 made of silicon nitride (SiN _x ) is formed on the gate lines 22, 24, and 26. Contact holes 71 and 72 are formed in the gate insulating film 30 to expose the gate pad 24 and the sustain electrode pad 28, respectively.

A semiconductor layer 40 made of a semiconductor such as hydrogenated amorphous silicon is formed on the gate insulating layer 30. The semiconductor layer 40 overlaps the gate electrode 26.

On the semiconductor layer 40, contact layers 55 and 56 made of a material such as n + hydrogenated amorphous silicon that are heavily doped with n-type impurities are formed. The contact layers 55 and 56 are separated on both sides with respect to the gate electrode 26.

On the contact layers 55 and 56, data lines 62, 64, 65 and 66 made of chromium (Cr) or molybdenum-tungsten alloy are formed. The data lines 62, 64, 65, and 66 are formed in a vertical direction and connected to the source electrode 65 formed on one contact layer 55, and one of the data line 62 and the data line 62. On the contact layer 56 connected to the end and separated from the data pad 64 and the data line 62 to which image signals from the outside are applied, and located opposite the source electrode 65 with respect to the gate electrode 26. A drain electrode 66 is formed. At this time, the data lines 62, 64, 65, and 66 may be formed in a single layer like the gate lines 22, 24, and 26, but may be formed in a double layer or a triple layer. Of course, when forming more than two layers, it is preferable that one layer is made of a material having a low resistance and the other layer is made of a material having good contact properties with other materials.

The gate wirings 22, 24, 26, the sustain electrode wirings 27, 28, the gate insulating film 30, the semiconductor layer 40, the contact layers 55, 56, and the data wirings 62, 64, 65 described above. , 66) can be modified in many other ways. For example, the gate wirings 22, 24, and 26 may be formed in an annular gate structure, and the sustain electrode wirings 27 and 28 may not be formed, and the contact layers 55 and 56 may include the data wirings 62 and 64. , 65, 66, and the like, and the semiconductor layer 40 may also be formed vertically along the data lines 62, 64, 65, and 66.

An auxiliary insulating film 70 made of an inorganic insulating material such as silicon nitride (SiNx) is formed on the data wires 62, 64, 65, and 66. In the auxiliary insulating layer 70, contact holes 71, 72, 73, and 74 are formed to expose the gate pad 24, the sustain electrode pad 28, the data pad 64, and the drain electrode 74, respectively. At this time, the auxiliary insulating film 70 is formed to a thickness of about 1,000 kHz, and is formed to prevent the channel portion from being contaminated to deteriorate the thin film transistor characteristics is not necessarily necessary.

The protective insulating layer 82 and the protrusion 81 made of the photosensitive organic insulating material are formed on the auxiliary insulating layer 70. A black pigment is added to the photosensitive organic insulating material constituting the protective insulating film 82 and the projection 81 so that light cannot pass through the protective insulating film 82 and the projection 81. This is to prevent light leakage due to abnormal arrangement of liquid crystal molecules on the protrusions 81. However, in some cases, the protective insulating film 82 and the projection 81 may be formed to be transparent.

The protective insulating layer 82 covers and protects at least the channel portion between the source electrode 65 and the drain electrode 66. In the present embodiment, the protective insulating layer 82 is formed of the drain electrode 66 and the data pad 64 as well as the channel portion. All of the data wirings 62, 64, 65, and 66 except for a part are covered.

The protrusions 81 are arranged in such a manner that several crosses are vertically connected to a pixel area, which is an area where two adjacent data lines 62 and two gate lines 22 cross each other. The projection 81 is also symmetrical in the vertical direction, and one of the horizontal branches overlaps the storage electrode line 27. This is to minimize the decrease in the aperture ratio by overlapping elements as far as possible through which light cannot pass.

A pixel electrode 91 made of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO) is formed on the protrusion 81, and the gate pad 24, the sustain electrode pad 28, and the data are formed. The auxiliary pads 92, 93, and 94 made of the same material as the pixel electrode 91 are formed on the pad 64.

The pixel electrode 91 is in contact with the exposed drain electrode 66, and the left and right sides are indented at regular intervals to form an opening. The openings are symmetrical up, down, left and right, and partition the pixel electrode 91 into four small regions. In addition, the pixel electrodes 91 are arranged so as to be symmetrical with respect to the projections 81 vertically and horizontally, so that the four small regions of the pixel electrodes 91 are divided into quarters by the projections 81, respectively.

The auxiliary pads 92, 93, and 94 are not essential to complement the adhesion between the pads 24, 28, and 64 and the external circuit device and to protect the pads, and their application is optional.

Here, although transparent ITO or IZO is mentioned as an example of the material of the pixel electrode 91, in the case of a reflective liquid crystal display device, an opaque conductive material may be used.

Next, a method of manufacturing a substrate for a liquid crystal display according to an exemplary embodiment of the present invention will be described in detail with reference to FIGS. 6A to 9B and FIGS. 3 to 5.

FIG. 6A is a layout view of a substrate in an intermediate step of a process of manufacturing a thin film transistor substrate according to a first embodiment of the present invention, and FIGS. 6B and 6C are taken along the lines VIb-VIb 'and VIc-VIc' of FIG. 6A, respectively. FIG. 7A is a layout view of a substrate in the next step of FIGS. 6A to 6C, and FIGS. 7B and 7C are cross-sectional views taken along lines XB-XB 'and XC-XC' of FIG. 7A, respectively. FIG. 8B is a cross sectional view taken along the line VIIb-VIIb 'and VIIc-VIIc' of FIG. 7A, respectively, to illustrate the alignment state of the photomask and the substrate in an intermediate stage from the steps of FIGS. 6A to 6C to the steps of FIGS. 7A to 7C. 9A and 9B are cross sectional views taken along the lines 'b-'b' and 'c-'c' of FIG. 7A, respectively, and are cross-sectional views of the substrate in the next steps of FIGS. 8A and 8B.

First, as shown in FIGS. 6A to 6C, a conductive layer such as a metal is deposited to a thickness of 1,000 Å to 3,000 으로 by a sputtering method and patterned using a first mask to form a gate line 22 on the substrate 10. The gate wiring including the gate pad 24 and the gate electrode 26 is formed.

Next, the gate insulating film 30, the amorphous silicon layer, and the doped amorphous silicon layer were successively deposited to the thicknesses of 1,500 kPa to 5,000 kPa, 500 kPa to 1,500 kPa, 300 kPa to 600 kPa, respectively, by chemical vapor deposition. Patterning using a mask forms a semiconductor layer 40 and a doped amorphous silicon pattern thereon.

Subsequently, a conductive layer such as a metal is deposited to a thickness of 1,500 Å to 3,000 Å by a method such as sputtering, and the conductor layer is patterned using a third mask to form a data line 62, a data pad 64, and a source electrode 65. ), And a data wiring including the drain electrode 66 is formed.

The manufacturing process described above describes a process of manufacturing a thin film transistor substrate using a general photomask, which is just one example. In addition, the gate wirings 22, 24, 26, the gate insulating film 30, The semiconductor layer 40, the contact layers 55 and 56, and the data lines 62, 64, 65, and 66 may be formed. For example, by forming a gate wiring, successively laminating a gate insulating film, a semiconductor layer, a contact layer, and a data metal layer, and patterning using an optical mask that can differentiate the light transmittance into three or more steps as described below. A method such as simultaneously forming a gate insulating film pattern, a semiconductor layer pattern, a contact layer pattern, and a data wiring is also possible.

Next, an inorganic insulating film such as silicon nitride (SiNx) is deposited to a thickness of about 1,000 GPa, and then a photosensitive organic insulating film such as a photosensitive resin is applied and patterned using a fourth mask, as shown in FIGS. 7A to 7C. The same auxiliary insulating film pattern 70, the protective insulating film pattern 82 and the projection 81 are formed. At this time, it is preferable that the photosensitive organic insulating film is applied to have a thickness of 1.9 μm or more, and that black light is added to block light. In addition, since the photosensitive organic insulating layer must be used as the protective insulating layer 82 protecting the data lines 62, 64, 65, and 66 together with the channel of the thin film transistor, the photosensitive organic insulating layer has good adhesion with ITO deposited in a subsequent process and etching of ITO. It is preferable to use a material that is not damaged during the process.

In order to form the auxiliary insulating film 70, the protective insulating film 82, and the protrusion 81 as described above, a photosensitive organic insulating film pattern having a different thickness is formed according to a portion thereof, and the lower layers are etched using this as an etching mask. It will be described in detail with reference to 8a to 9b.

First, as shown in FIGS. 8A to 8B, the photosensitive organic insulating layer 80 is coated on the auxiliary insulating layer 70 and exposed through the photomask 100 which can differentiate the light transmittance into three or more steps depending on the portion. . In this case, the photomask is formed of a transparent substrate 110 and a light blocking layer 120 formed below the light blocking layer 120, a part of which is removed, and a part of the light mask is formed. At this time, the slit pattern is formed with a size smaller than the resolution of the exposure equipment.

The state in which the optical mask 100 is aligned is as follows. A portion in which the intact light blocking layer 120 is formed corresponds to a portion A on which the protective insulating layer 82 and the protrusion 81 are to be formed, and the upper portions of the pads 24, 28, and 64 and the drain electrode 66. A portion through which the light blocking layer 120 is removed to allow light to pass therethrough corresponds to (B), and a portion on which the slit is formed corresponds to the remaining portion C.

As illustrated in FIGS. 8A and 8B, the photosensitive organic insulating layer 80 exposed through the photomask 100 may have different decomposition states of polymers. That is, the portion B of the photosensitive organic insulating layer 80 exposed to light through the portion of the light blocking layer 120 removed is in a state in which the polymer is decomposed to the lower portion, and is exposed to light through the portion in which the slit is formed. Part C reacts with light only up to a certain depth from the surface to decompose the polymer, and the polymer remains underneath, and the part that is not exposed to light because it is covered by the light blocking layer 120 remains undecomposed. have.

In the above, the case where the positive photosensitive organic insulating film is used is described, but it is also possible to use the negative photosensitive organic insulating film, in which case the amount of light irradiation should be reversed from the present embodiment. In addition, the amount of light mask can be controlled by using a mosaic pattern or a semi-transmissive layer without using a slit pattern.

When the exposed photosensitive organic insulating film 80 is developed through the above process, a photosensitive organic insulating film pattern as shown in FIGS. 9A and 9B is obtained. That is, the photosensitive organic insulating layer 80 remains thick in the portion A in which the protective insulating layer 82 and the protrusion 81 are to be formed, and the pads 24, 28, 64 and the upper portion B of the drain electrode 66. The photosensitive organic insulating layer 80 is removed, and the photosensitive organic insulating layer 80 remains thin in the remaining portion C. At this time, the thickness of the photosensitive organic insulating film 80 of the portion A remains almost intact, and the portion C remains at a thickness of about 5,000 kPa.

Using the photosensitive organic insulating layer 80 pattern as an etching mask, the exposed auxiliary insulating layer 70 and the lower gate insulating layer 30 are etched to expose the pads 24, 28, 64 and the drain electrode 66. . In this case, it is common to use dry etching.

Next, the protective insulating film 82 and the protrusion 81 are completed by removing all of the C photosensitive organic insulating film 80 through ashing or dry etching. At this time, the thickness of the protective insulating film 82 and the projection 81 is about 1.4 mu m.

Finally, a conductive material such as ITO or IZO is deposited and patterned using a fifth mask to form the pixel electrode 91 and each pad 24, 28, and 64 having an opening pattern and connected to the drain electrode 66. Covering auxiliary pads 92, 93, 94 are formed.

Next, the driving characteristics of the liquid crystal display using the thin film transistor substrate described above will be described with reference to the drawings.

10 is a cross-sectional view of a liquid crystal display device using the thin film transistor substrate according to the first embodiment of the present invention.

In the liquid crystal display, the liquid crystal material 300 is vertically aligned between the thin film transistor substrate 10 and the opposing substrate 200, and a polarizer (not shown) is attached to the upper and lower substrates 10 and 200. Has a structure.

A color filter (not shown), a black matrix (not shown), and the like are usually formed on the counter substrate 200 together with the common electrode 210. In this case, since it is not necessary to form an opening pattern or protrusion in the common electrode 210, various problems caused by patterning the common electrode 210 are eliminated.

When the driving circuit is connected to the liquid crystal display and driven, when the voltage difference between the common electrode 210 and the pixel electrode 91 is less than or equal to the threshold voltage Vth, the liquid crystal molecules 300 do not move but the voltage difference is greater than or equal to Vth. When the liquid crystal molecules 300 start to lie down. The liquid crystal molecules 300 positioned at the periphery of the pixel electrode 91 are inclined toward the center of the pixel electrode by a fringe field, and the liquid crystal molecules 300 on the central protrusion 81 of the pixel electrode 91. Is inclined toward the center of the pixel electrode 91 similarly to the liquid crystal molecules 300 positioned at the periphery due to the distortion of the electric field direction formed by the protrusion 81. Therefore, a domain is formed around the protrusion. At this time, if the protrusions 81 and the pixel electrodes 91 are formed in the same manner as in the embodiment of the present invention, four domains are formed at 45 ° with respect to the up, down, left, and right directions. This makes the viewing angle constant up, down, left and right.

A thin film transistor substrate for a liquid crystal display device according to a second embodiment of the present invention will be described.

11 is a layout view of a thin film transistor substrate according to a second exemplary embodiment of the present invention, and FIGS. 12 and 13 are cross-sectional views taken along lines XII-XII 'and XIII-XIII' of FIG. 11, respectively.

The thin film transistor substrate according to the second embodiment includes the gate wirings 22, 24, 26, the sustain electrode wirings 27, 28, the gate insulating film 30, the semiconductor layer 40, the contact layers 55, 56, and data. The wirings 62, 64, 65 and 66 have the same structure as in the first embodiment.

Contact holes 71, 72, 73, 74 exposing the gate pad 24, the sustain electrode pad 28, the data pad 64, and the drain electrode 66 on the data lines 62, 64, 65, 66, respectively. The protective film 70 which has () is formed. The passivation layer 70 may be formed of an organic insulating material such as silicon nitride or acrylic, and may cover and protect at least a channel portion between the source electrode 65 and the drain electrode 66 of the semiconductor layer 40.

On the passivation layer 70, the pads 24, 28, and 64 exposed through the contact holes 71, the pixel electrodes 91 connected to the drain electrode 66, and the contact holes 71, 72, and 73 are disposed. Covering auxiliary pads 92, 93, 94 are formed.

A protrusion 81 made of a photosensitive material is formed on the pixel electrode 91.

At this time, the shape of the pixel electrode 91 and the projection 81 is the same as in the first embodiment. The protrusion 81 is formed below the pixel electrode 91 in the first embodiment, but the protrusion 81 is formed above the pixel electrode 91 in the second embodiment.

Next, a method of manufacturing a thin film transistor substrate according to a second embodiment of the present invention will be described.

14A is a layout view of a substrate in an intermediate step of a process of manufacturing a thin film transistor substrate according to a first embodiment of the present invention, and FIGS. 14B and 14C are XIVb-XIVb 'lines and XIVc-XIVc', respectively, of FIG. 14A. 15A and 15B are cross sectional views taken along lines XIVb-XIVb 'and XIVc-XIVc' of FIG. 14A, respectively, and the alignment state between the substrate and the photomask in the previous steps of FIGS. 14A to 14C. It is a figure which shows.

The method of manufacturing the thin film transistor substrate also includes the gate wirings 22, 24, 26 and the sustain electrode wirings 27, 28, the gate insulating film 30, the semiconductor layer 40, the contact layers 55, 56, and the like. The formation of the data lines 62, 64, 65, and 66 is the same as in the first embodiment.

Next, an inorganic insulating material such as silicon nitride is deposited by a chemical vapor deposition (CVD) method or by spin coating an organic insulating material to deposit and pattern a protective film 70 having a thickness of 3,000 Å or more, thereby forming pads 24, 28, and 64. A contact hole for exposing the drain electrode 66 is formed.

Subsequently, a conductive layer such as ITO or IZO is deposited to a thickness of between 300 mW and 1,000 mW and a photosensitive film is applied on the conductive layer. At this time, it is preferable to apply | coat a photosensitive film so that it may become 1.9 micrometers or more, and to add a black pigment | dye to block light. Next, the photosensitive film pattern 80 as shown in FIGS. 14A to 14C is formed by exposing through a photomask 100 capable of differentiating the light transmittance in three or more stages depending on the portion. The conductive layer is etched using the etching mask to form the pixel electrode 91 having the opening pattern and the auxiliary pads 92, 93, and 94.

In order to form the photosensitive film pattern 80 as described above, the optical mask 100 is exposed through the optical mask 100 as shown in FIGS. 15A and 15B. In this case, the photomask is formed of a transparent substrate 110 and a light blocking layer 120 formed thereunder. The light blocking layer 120 is partially removed and a slit pattern is formed. At this time, the slit pattern is formed with a size smaller than the resolution of the exposure equipment.

The state in which the optical mask 100 is aligned is as follows. The portion A on which the protrusion 81 is to be formed corresponds to the portion on which the intact light blocking layer 120 is formed, and the pads 24, 28, 64 and the portion C on which the pixel electrode 91 is to be formed. The part in which the slit is formed is corresponded, and the remainder part C corresponds to the part through which the light blocking layer 120 is removed and light can pass through as it is.

The photosensitive film pattern 80 as shown in Figs. 14A to 14C can be obtained by exposing and developing the photosensitive film with the photomask aligned as described above. That is, a thick photoresist film is left at a portion where the protrusion 81 is to be formed, and a thin photoresist film is left at a portion where the pixel electrode 91 and the auxiliary pads 92, 93, and 94 are to be formed. At this time, the thickness of the thin portion of the photosensitive film pattern 80 is about 5,000 kPa, and the thickness of the thick portion is about 1.9 µm.

The conductive layer is etched using the photoresist pattern 80 as an etch mask to form the pixel electrode 91 and the auxiliary pads 92, 93, and 94 having an opening pattern, and then the ashing or dry etching of the photoresist pattern 80 is performed. All the thin portions of the photoresist pattern 80 are removed to form the protrusions 81. At this time, the thickness of the projections is about 1.4 µm.

Next, the driving characteristics of the liquid crystal display using the thin film transistor substrate described above will be described with reference to the accompanying drawings.

16 is a cross-sectional view of a liquid crystal display using a thin film transistor substrate according to a second embodiment of the present invention.

The structure of the liquid crystal display according to the second embodiment is the same as that of the first embodiment except for the difference in the structure of the thin film transistor substrate described above.

The principle of forming the domain in four directions by adjusting the tilting direction of the liquid crystal molecules using the fringe field is also almost similar to that of the first embodiment. However, in the second embodiment, the electric field is distorted due to the difference in dielectric constant between the protrusion 81 formed on the pixel electrode and the liquid crystal material 300.

When the thin film transistor substrate is manufactured in the above-described manner, an opening pattern and protrusions can be formed to secure a wide viewing angle without any additional process as compared with a conventional vertically aligned liquid crystal display device, and the patterned common electrode of the upper plate can be eliminated without patterning. This eliminates the problem of increasing the common electrode voltage or forming an expensive overcoat film. In addition, since the protrusions are formed of the photosensitive organic layer, the height of the protrusions is easily controlled, and the protrusions are formed uniformly with smooth slanting without sharp angles, thereby preventing the domains from being disturbed.

Claims (19)

Insulated substrate (correction), A gate line formed on the insulating substrate, A gate insulating film formed on the gate line, A semiconductor layer formed on the gate insulating layer and partially overlapping the gate line; A contact layer formed on the semiconductor layer and separated on both sides with respect to a gate electrode which is a part of the gate line; A source electrode formed on one side of the contact layer, A drain electrode formed on the other side of the contact layer, A data line formed on the gate insulating layer and crossing the gate line and connected to the source electrode; A protective insulating film covering at least the semiconductor layer between the source electrode and the drain electrode and made of a photosensitive organic insulating material, A protrusion formed of the same material as the protective insulating layer and formed in the pixel area where the two adjacent data lines and the two adjacent gate lines intersect each other; A pixel electrode formed on the protrusion and connected to the drain electrode and having an opening pattern Thin film transistor substrate comprising a. In claim 1, And a second insulating film formed under the protective insulating film and covering at least the semiconductor layer between the source electrode and the drain electrode, the auxiliary insulating film made of an inorganic material. In claim 2, The auxiliary insulating layer is a thin film transistor substrate made of silicon nitride. The method according to any one of claims 1, 2 and 3, And the opening patterns of the protrusions and the pixel electrodes are symmetrical with each other and are alternately arranged. In claim 4, The projections have a form in which several crosses are vertically connected, and the pixel electrode is divided into a plurality of small regions by the opening pattern, and the projections divide each small region of the pixel electrode into four equal parts. A thin film transistor substrate. The method according to any one of claims 1, 2 and 3, A storage electrode line formed on the substrate in parallel with the gate line; And the storage electrode line overlaps at least a portion of the protrusion. The method according to any one of claims 1, 2 and 3, The projection is thin film transistor substrate, characterized in that black. Insulated substrate (correction), A gate line formed on the insulating substrate, A gate insulating film formed on the gate line, A semiconductor layer formed on the gate insulating layer and partially overlapping the gate line; A contact layer formed on the semiconductor layer and separated on both sides with respect to a gate electrode which is a part of the gate line; A source electrode formed on one side of the contact layer, A drain electrode formed on the other side of the contact layer, A data line formed on the gate insulating layer and crossing the gate line and connected to the source electrode; A protective film formed on the source electrode, the drain electrode and the data line and having a contact hole exposing the drain electrode; A pixel electrode formed on the passivation layer and connected to the drain electrode through the contact hole; A protrusion formed on the pixel electrode and made of a photosensitive organic material Thin film transistor substrate comprising a. In claim 8, And the opening patterns of the protrusions and the pixel electrodes are symmetrical with each other and are alternately arranged. In claim 9, The projections have a form in which several crosses are vertically connected, and the pixel electrode is divided into a plurality of small regions by the opening pattern, and the projections divide each small region of the pixel electrode into four equal parts. A thin film transistor substrate. In claim 8, A storage electrode line formed on the substrate in parallel with the gate line; And the storage electrode line overlaps at least a portion of the protrusion. In claim 8, The projection is thin film transistor substrate, characterized in that black. A storage electrode line formed on the substrate in parallel with the gate line; And the storage electrode line overlaps at least a portion of the protrusion. Forming a gate line on the insulating substrate, the gate line including a gate line, a gate pad connected to the gate line, and a gate electrode that is a part of the gate line; A data line including a gate insulating layer, a semiconductor layer, a contact layer and a data line on the gate line, a source electrode connected to the data line, a drain electrode facing the source electrode, and a data pad connected to one end of the data line; Forming a step, Forming a projection and a protective insulating film made of a photosensitive organic insulating material, Forming a pixel electrode connected to the drain electrode on the protrusion and having an opening pattern; Method of manufacturing a thin film transistor substrate comprising a. In claim 13, And forming an auxiliary insulating layer made of an inorganic material on the data line before the forming of the protective insulating layer and the protrusion. The method of claim 13 or 14, And forming first and third contact holes exposing the gate pad, the data pad, and the drain electrode, respectively, in the forming of the protective insulating layer and the protrusion. The method of claim 15, Forming the protective insulating film and the projections Stacking a photosensitive organic insulating film, Exposing the photosensitive organic insulating layer through a photomask having a first portion, a second portion, and a third portion, each having a different light transmittance according to a portion; The second photosensitive organic insulating layer is developed to have a first thickness at a portion where the protective insulating layer and the protrusion are to be formed, and to have a thickness above the gate pad, the data pad, and the drain electrode, and to be thinner than the first thickness at other portions. Forming a photosensitive organic insulating layer pattern having a thickness, Etching the lower insulating layer using the photosensitive organic insulating layer pattern as an etch mask to expose the gate pad, the data pad, and the drain electrode; Ashing the photosensitive organic insulating layer pattern to remove the portion having the second thickness, leaving only the protective insulating layer and the protrusions. Method of manufacturing a thin film transistor substrate comprising a. Forming a gate line on the insulating substrate, the gate line including a gate line, a gate pad connected to the gate line, and a gate electrode that is a part of the gate line; A data line including a gate insulating layer, a semiconductor layer, a contact layer, a source electrode connected to a data line and the data line, a drain electrode facing the source electrode, and a data pad connected to one end of the data line on the gate line; Forming a passivation layer formed on the data line and having first to third contact holes exposing the gate pad, the data pad, and the drain electrode, respectively; Forming a protrusion formed on the pixel electrode together with a pixel electrode and formed of a photosensitive material Method of manufacturing a thin film transistor substrate comprising a. The method of claim 17, And forming an auxiliary gate pad and an auxiliary data pad covering the gate pad and the data pad, respectively, in the forming of the pixel electrode. The method of claim 17 or 18, Forming the protrusion together with the pixel electrode Laminating the ITO layer, Stacking a photoresist film on the ITO layer, Exposing the photosensitive film through an optical mask having a first portion, a second portion, and a third portion, each having a different light transmittance according to a portion; The photoresist film is developed to have a first thickness at a portion where the protrusion is to be formed, and a second thickness thinner than the first thickness at a portion where the pixel electrode, the auxiliary gate pad, and the auxiliary data pad are to be formed, and at other portions. Forming a photoresist pattern having no thickness, Etching the ITO layer using the photoresist pattern as an etch mask to form the pixel electrode, the auxiliary gate pad, and the auxiliary data pad; Ashing the photoresist pattern to remove the portion having the second thickness, leaving only the protrusions. Method of manufacturing a thin film transistor substrate comprising a.