KR20030046102A - a thin film transistor substrate and a method for manufacturing the same - Google Patents

Abstract

PURPOSE: A TFT substrate for a reflective liquid crystal display device and a method for fabricating the same are provided to maximize the area contacting an anisotropy conductive film by forming auxiliary gate or data pads with concave and convex surfaces, thereby maximizing the adhesion of the anisotropy conductive film. CONSTITUTION: A TFT substrate for a reflective liquid crystal display device includes gate wires formed on an insulating substrate(10) with gate lines and gate electrodes connected to the gate lines, auxiliary pads(27) formed on the insulating substrate and formed of at least two or more patterns, a gate insulating film(30) covering the gate wires, a semiconductor layer formed on the gate insulating film on the gate electrodes, data wires formed on the gate insulating film or the semiconductor layer, and pixel electrodes electrically connected to drain electrodes. The data wires includes data lines intersecting the gate lines, source electrodes connected to the data lines and adjacent to the gate electrodes, drain electrodes facing the source electrodes with respect to the gate electrodes, and data pads(68) connected to the data lines, formed on the auxiliary pads and having concave and convex surface.

Description

A thin film transistor substrate and a method for manufacturing the same

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a thin film transistor substrate, and more particularly, to a method for manufacturing a thin film transistor substrate used in a reflective liquid crystal display device for displaying an image using external light.

The liquid crystal display is one of the most widely used flat panel display devices. The liquid crystal display includes two substrates on which electrodes are formed and a liquid crystal layer interposed therebetween, and rearranges the liquid crystal molecules of the liquid crystal layer by applying a voltage to the electrode. By controlling the amount of light transmitted.

Among the liquid crystal display devices, a liquid crystal display device having a thin film transistor that has electrodes formed on two substrates and switches a voltage applied to the electrodes is generally used among liquid crystal display devices, and a thin film transistor is generally formed on one of two substrates. .

The liquid crystal display device transmits light emitted by a backlight, which is a specific light source, to a transparent electrode, which is a pixel electrode of a liquid crystal panel, to display an image, and to reflect external light including natural light, which is a pixel electrode of a liquid crystal panel. It can be divided into the reflective mode in which the image is reflected to the image.

In the liquid crystal display, the substrate on which the thin film transistor is formed is called a thin film transistor substrate. In the center of the thin film transistor substrate, a plurality of wirings defining pixel regions of a matrix array and transferring scan signals or image signals are formed to cross each other. Each pixel region is provided with a pixel electrode through which the image signal is transmitted through the thin film transistor according to the scan signal. In addition, a plurality of pads connected to the ends of the wirings and receiving image signals or scan signals from the outside and transferred to the wirings are clustered in predetermined units.

Here, each pad is electrically connected to an output end of a driving integrated circuit for outputting a scan signal or an image signal, which is attached to the top of the pad by attaching an anisotropy conductive film containing conductive particles on top of the pad. It is common to align the pads with the output and to apply pressure to them. In this case, in order to secure contact between the pads of the thin film transistor substrate and the anisotropic conductive film, it is advantageous to ensure that each pad has a wide contact area with the anisotropic conductive film.

An object of the present invention is to provide a thin film transistor substrate for a liquid crystal display device having a pad capable of securing a contact area, and a manufacturing method thereof.

1 is a layout view illustrating a structure of a thin film transistor substrate for a reflective liquid crystal display device according to an exemplary embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along the line II-II 'of FIG. 1;

3A, 4A, 5A, and 7A are layout views of a thin film transistor substrate in an intermediate process of manufacturing a thin film transistor substrate for a transflective liquid crystal display device according to an embodiment of the present invention;

3B is a cross-sectional view taken along the line IIIb-IIIb ′ in FIG. 3A;

4B is a cross-sectional view taken along the line IVb-IVb ′ in FIG. 4A and is a cross-sectional view showing the next step in FIG. 3B;

FIG. 5B is a cross-sectional view taken along the line Vb-Vb ′ in FIG. 5A and is a cross-sectional view showing the next step in FIG. 4B;

FIG. 6B is a cross-sectional view taken along the line VIb-VIb ′ in FIG. 6A, and is a cross-sectional view illustrating the next step of FIG. 5B.

In the thin film transistor substrate for a liquid crystal display device and a method of manufacturing the same according to the present invention, the pad is formed in two or more patterns or at least two or more auxiliary patterns are formed under the pad so that the pad has an uneven surface.

In detail, the thin film transistor substrate for a liquid crystal display according to the present invention includes a gate line including a gate line, a gate electrode connected to the gate line, and an auxiliary pad formed of two or more patterns on the insulating substrate. A semiconductor layer is formed on the gate electrode over the gate insulating film covering the gate wiring, and a data line intersecting the gate line and a source electrode connected to the data line and adjacent to the gate electrode and opposite to the source electrode with respect to the gate electrode. A data line including a data pad connected to the drain electrode and the data line positioned in the upper side of the auxiliary pad and having an uneven surface is formed, and a pixel electrode electrically connected to the drain electrode is formed.

In this case, the thin film transistor substrate may further include a passivation layer formed between the pixel electrode and the data line and having a first contact hole to which the drain electrode and the pixel electrode are connected and a second contact hole to expose the data pad. In addition, it is preferable to further include an auxiliary data pad formed of the same layer as the pixel electrode and connected to the data pad through the second contact hole and having an uneven surface such as the data pad.

In addition, the gate wiring further includes a gate pad configured to receive a scan signal from the outside and transmit the scan signal to the gate line, wherein the passivation layer has a third contact hole for exposing the gate pad together with the gate insulating layer, and a third contact on the same layer as the pixel electrode. An auxiliary gate pad is further formed to be electrically connected to the gate pad through the hole. In this case, the gate pad is formed in at least two patterns, and the auxiliary gate pad covering the gate pad has an uneven surface.

The pixel electrode may be made of a transparent conductive material or a conductive material having reflectivity.

Next, a thin film transistor substrate for a liquid crystal display device and a method of manufacturing the same according to embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. do.

In the exemplary embodiment of the present invention, a thin film transistor substrate for a reflective liquid crystal display device that displays an image by using a reflective electrode on a pixel electrode and reflects external light onto the reflective film will be described. first,

1 and 2 will be described in detail with respect to the structure of the thin film transistor substrate for a reflective liquid crystal display device according to an embodiment of the present invention.

1 is a layout view of a thin film transistor substrate for a reflective liquid crystal display according to an exemplary embodiment of the present invention, and FIG. 2 is a cross-sectional view of the thin film transistor substrate illustrated in FIG. 1 taken along the line II-II ′.

On the insulating substrate 10, a single wiring made of silver or silver alloy or aluminum or aluminum alloy having low resistance, or a gate wiring made of such a single film and a multilayer film containing chromium, molybdenum, molybdenum alloy and the like is formed. The gate line is connected to the gate line 22 and the end of the gate line 22 extending in the horizontal direction, and receives a gate signal from the outside and transmits the gate signal to the gate line 22. The gate pad 24 has at least two patterns. ) And a gate electrode 26 of the thin film transistor connected to the gate line 22. In addition, an auxiliary pad 27 having at least two patterns is formed on the substrate 10 of the data pad part where the data pad 68 is formed. Here, the gate line 22 overlaps with the reflective film 82 of a neighboring pixel region to be formed later to form a storage capacitor, and when the storage capacitor is insufficient, the gate wiring may be a common electrode voltage input to the common electrode of the upper plate. The sustain electrode may further include a sustain electrode configured to receive a voltage from the outside, and the sustain electrode overlaps the reflective film 82 to be described later to form a sustain capacitor to improve the charge retention capability of the pixel.

On the substrate 10, a gate insulating film 30 made of silicon nitride (SiN _x ) covers the gate wirings 22, 24, and 26.

A semiconductor layer 40 made of a semiconductor such as amorphous silicon is formed on the gate insulating film 30 of the gate electrode 24, and n + having a high concentration of silicide or n-type impurity is formed on the semiconductor layer 40. Resistive contact layers 55 and 56 made of a material such as hydrogenated amorphous silicon are formed, respectively. Although the semiconductor layer 400 is formed only on the gate electrode 26, the semiconductor layer 400 may be formed in the vertical direction along the data line 62 to prevent the data line 62 formed later from being disconnected due to the step difference. Can be.

On the ohmic contacts 55 and 56 and the gate insulating film 30, a data line made of a low resistance conductive material such as aluminum or silver or a conductive film made of chromium, molybdenum or molybdenum alloy or the like is formed. The data line is formed in a vertical direction and intersects the gate line 22 to define a pixel region, and a source electrode connected to the data line 62 and the upper portion of the resistance contact layer 55 connected to the data line 62. 65, a data pad 68 and a source electrode connected to one end of the data line 62 and receiving an image signal from the outside and transferring the image signal to the data line 62, and formed on the auxiliary pad 27. And a drain electrode 66 which is separated from the 65 and formed on the ohmic contact layer 56 opposite the source electrode 65 with respect to the gate electrode 26. In this case, the data pad 68 is formed on the auxiliary pad 27 having a plurality of patterns to have an uneven surface.

On the data lines 62, 65, 66, and 68, and on the semiconductor layer 40, which is not covered by the data lines, an organic material having excellent planarization characteristics and photosensitive or silicon nitride or a low dielectric constant insulating material formed by chemical vapor deposition having a low dielectric constant. A protective film 70 is formed. At this time, the surface of the protective film 70 has a concave-convex surface in order to maximize the reflection efficiency of the reflective film 82 formed later.

In the passivation layer 70, contact holes 76 and 78 are formed to expose the drain electrode 66 and the data pad 68, respectively. The contact hole 74 exposing the gate pad 24 together with the gate insulating layer 30 is formed. Is formed. In this case, the contact holes 74 and 78 exposing the gate pad 24 and the data pad 68 are formed larger than the concave-convex pattern 27 disposed under the gate pad 24 and the data pad 68.

The reflective film 82 is electrically connected to the drain electrode 66 through the contact hole 76 on the passivation layer 70 and positioned in the pixel area and made of a conductive material having excellent reflectivity such as silver, silver alloy, aluminum, or aluminum alloy. ) Is formed. In addition, the auxiliary gate pad 84 and the auxiliary data pad 88, which are connected to the gate pad 24 and the data pad 68, respectively, are formed on the passivation layer 70 through the contact holes 74 and 78. At this time, the auxiliary gate pad 84 covers the gate pad 24 formed of a plurality of patterns to have a concave-convex surface, and the auxiliary data pad 88 is also formed on an upper portion of the data pad 68 having a concave-convex surface to form a concave-convex surface. Has Therefore, the contact area of the anisotropic conductive film used later for connecting a drive integrated circuit can be ensured to the maximum. Here, the auxiliary gates and data pads 84 and 88 are for protecting the gate and data pads 24 and 68, but are not essential.

Next, a method of manufacturing a thin film transistor substrate according to an exemplary embodiment of the present invention will be described in detail with reference to FIGS. 3A to 6B and FIGS. 1 and 2.

First, as shown in FIGS. 3A and 3B, a low-resistance conductive material is stacked on the glass substrate 10 and patterned by a photolithography process using a mask to form the gate line 22, the gate electrode 26, and the like. Auxiliary pads 27 having a plurality of patterns are formed in the horizontal gate line and the data pad portion including the gate pads 24 having a plurality of patterns.

Next, as shown in FIGS. 4A and 4B, a three-layer film of a gate insulating film 30 made of silicon nitride, a semiconductor layer 40 made of amorphous silicon, and a doped amorphous silicon layer 50 is successively laminated, and a mask is formed. The semiconductor layer 40 and the ohmic contact layer 50 are formed on the gate insulating layer 30 facing the gate electrode 24 by patterning the semiconductor layer 40 and the doped amorphous silicon layer 50 by the patterning process. do.

Next, as shown in FIGS. 5A to 5B, after stacking the conductive film for data wiring, patterning is performed by a photolithography process using a mask to connect the data line 62 and the data line 62 crossing the gate line 22. The source electrode 65 and the data line 62 extending to the upper portion of the gate electrode 26 are separated from the data pad 68 and the source electrode 65 connected to one end thereof, and the center of the gate electrode 26 is centered. As a result, a data line including a drain electrode 66 facing the source electrode 65 is formed.

Subsequently, the doped amorphous silicon layer pattern 50, which is not covered by the data lines 62, 65, 66, and 68, is etched and separated on both sides of the gate electrode 26, while both doped amorphous silicon layers ( The semiconductor layer pattern 40 between 55 and 56 is exposed. Subsequently, in order to stabilize the surface of the exposed semiconductor layer 40, it is preferable to perform oxygen plasma.

Next, as shown in FIGS. 6A and 6B, the passivation layer 70 is formed by coating an organic material having excellent planarization characteristics and photosensitive properties on the substrate 10. Subsequently, patterning is performed together with the gate insulating film 30 in a photolithography process using a mask to form contact holes 74, 76, and 78 that expose the gate pad 24, the drain electrode 66, and the data pad 68. A concave-convex pattern is formed on the passivation layer 70.

Next, as shown in FIGS. 1 and 2, conductive materials including silver or aluminum having reflectance are stacked and patterned by a photolithography process using a mask to be connected to the drain electrode 66 through the contact hole 76. An auxiliary gate pad 86 and an auxiliary data pad 88 which are connected to the gate pad 24 and the data pad 68, respectively, are formed through the reflective film 82 and the contact holes 74 and 78, respectively.

In the exemplary embodiment of the present invention, a thin film transistor substrate for a reflective liquid crystal display has been described. However, the present invention may be applied to a thin film transistor substrate for a transmissive liquid crystal display using a pixel electrode as a transparent conductive material. In addition, a driving integrated circuit may be directly mounted on the thin film transistor substrate for a reflective or transmissive liquid crystal display according to the present invention, or a package including the driving integrated circuit may be mounted.

As described above, in the present invention, the auxiliary gate pad or the auxiliary data pad through which the signal is transmitted from the outside may be formed to have an uneven surface to maximize the area to which the anisotropic conductive film is bonded, thereby maximizing the adhesive force of the anisotropic conductive film.

Claims (6)

A gate wiring formed on an insulating substrate and including a gate line and a gate electrode connected to the gate line; An auxiliary pad formed on the insulating substrate and formed of two or more patterns; A gate insulating film covering the gate wiring, A semiconductor layer formed on the gate insulating film of the gate electrode; A data line intersecting the gate line, a source electrode connected to the data line and adjacent to the gate electrode, and positioned opposite to the source electrode with respect to the gate electrode; A data line connected to a drain electrode and the data line and including a data pad formed on the auxiliary pad and having an uneven surface; A thin film transistor substrate for a liquid crystal display device comprising a pixel electrode electrically connected to the drain electrode. In claim 1, And a passivation layer formed between the pixel electrode and the data line and having a first contact hole to which the drain electrode and the pixel electrode are connected and a second contact hole to expose the data pad. Board, In claim 1, And an auxiliary data pad formed of the same layer as the pixel electrode and connected to the data pad through the second contact hole, and having an uneven surface, such as the data pad. In claim 3, The gate line further includes a gate pad receiving a scan signal from the outside and transferring the scan signal to the gate line, The passivation layer has a third contact hole exposing the gate pad together with the gate insulating layer, And an auxiliary gate pad electrically connected to the gate pad through the third contact hole in the same layer as the pixel electrode. In claim 4, The gate pad is formed of at least two patterns, and the auxiliary gate pad covers the gate pad and has a concave-convex surface, the thin film transistor substrate for a liquid crystal display device; In claim 1, The pixel electrode is a thin film transistor substrate for a liquid crystal display device made of a transparent conductive material or a conductive material having a reflectivity.