KR20020078294A - A thin film transistor array substrate and a method for manufacturing the same - Google Patents

Abstract

PURPOSE: A thin film transistor array board and a method for manufacturing the same are provided to minimize manufacturing expenses by simplifying the manufacturing process. CONSTITUTION: A method for manufacturing a thin film transistor array board includes the steps of accumulating and patterning conductive materials for a pixel electrode and a gate wiring on an insulating board(10) in order to form a lower conductive film pattern including pixel electrodes(20) and an upper conductive film pattern including a gate wiring having a gate line(32) and a gate electrode(36); forming a gate insulating film pattern covering the gate wiring; forming a semiconductor pattern on the gate insulating film pattern; removing the upper conductive film pattern not covered by the gate insulating film pattern; forming a data wiring including a data line, a source electrode connected to the data lines, a drain electrode separated from the source electrode by patterning the conductive material for a data wiring; forming the gate insulating pattern and the semiconductor pattern by a photolithography using a photosensitive film pattern(112,114) having partially different thickness.

Description

A thin film transistor array substrate and a method of manufacturing the same {A THIN FILM TRANSISTOR ARRAY SUBSTRATE AND A METHOD FOR MANUFACTURING THE SAME}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film transistor substrate and a method of manufacturing the same, and more particularly, to a thin film transistor substrate used as a substrate of a liquid crystal display device and a method of manufacturing the same.

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 for forming an electrode on each of two substrates and switching a voltage applied to the electrode is generally used. The thin film transistor is generally formed on one of two substrates.

The substrate on which the thin film transistor is formed is generally manufactured through a photolithography process using five or six masks. At this time, it is preferable to reduce the number of masks in order to reduce the production cost.

An object of the present invention is to simplify the method of manufacturing a thin film transistor array substrate.

1 is a thin film transistor substrate for a liquid crystal display according to an embodiment of the present invention,

FIG. 2 is a cross-sectional view of the thin film transistor substrate illustrated in FIG. 1 taken along the line II-II.

3A is a layout view of a thin film transistor substrate in a first process of manufacturing a thin film transistor substrate for a liquid crystal display according to an exemplary embodiment of the present invention.

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

FIG. 4 is a cross-sectional view taken along line IIIb-IIIb 'of FIG. 3a and is a cross-sectional view showing the next step of FIG. 3b;

5A is a diagram illustrating a process of manufacturing a thin film transistor substrate for a liquid crystal display according to an exemplary embodiment of the present invention.

FIG. 5B is a cross-sectional view illustrating the next step of FIG. 4, taken along the line Vb-Vb ′ in FIG. 5A.

6, 7 and 8 are cross-sectional views sequentially taken along the line Vb-Vb ′ in FIG. 5A and sequentially illustrating the next steps of FIG. 5B.

In order to solve this problem, the gate wiring and the pixel electrode are formed in one photolithography process, and the gate insulating layer pattern exposing the wiring to be connected to the semiconductor pattern and the external driving integrated circuit is formed in one photolithography process.

First, in the method for manufacturing a thin film transistor array substrate according to the present invention, first, a conductive material for a pixel electrode and a conductive material for a gate wiring are sequentially stacked and patterned on an insulating substrate to form a lower conductive film pattern including a pixel electrode, a gate line, and a gate. An upper conductive film pattern including gate wirings having electrodes is formed. Subsequently, a gate insulating film pattern covering the gate wiring and a semiconductor pattern thereon are formed, and the upper conductive film pattern not covered by the gate insulating film pattern is removed. Next, the conductive material for data wiring is patterned to form a data wiring including a data line, a source electrode connected to the data line, and a drain electrode separated from the source electrode. In this case, the gate insulating layer pattern and the semiconductor pattern are partially formed by a photolithography process using a photoresist pattern having a different thickness.

Here, the photoresist pattern includes a first portion having a first thickness, a second portion having a second thickness thicker than the first thickness, and a third portion having little thickness and excluding the first and second portions. In the photolithography process, it is preferable to form the second portion corresponding to the semiconductor pattern and the first portion corresponding to the gate insulating layer pattern.

An ohmic contact layer pattern may be formed between the data wirings and the semiconductor pattern, and in order to form the gate insulation layer pattern, the semiconductor pattern, and the ohmic contact layer pattern, first, the gate insulation layer, the semiconductor layer, and the ohmic contact layer are sequentially stacked and formed on the upper portion thereof. A photosensitive film is formed. Subsequently, the photoresist film is exposed and developed to form a photoresist pattern having first to third portions, and the gate insulating film, the semiconductor layer, and the ohmic contact layer are etched using the photoresist pattern of the first and second portions as an etching mask. Complete the pattern. Subsequently, the semiconductor layer and the ohmic contact layer are etched using the photoresist pattern of the second portion as an etch mask to complete the semiconductor pattern and the ohmic contact layer pattern.

The method may further include etching the resistive contact layer pattern that is not covered by the data line, and the semiconductor pattern may be plasma treated.

In the photolithography process, the photoresist pattern may be formed using an optical mask including a first region, a second region having a lower transmittance than the first region, and a third region having a higher transmittance than the first region. In order to adjust the transmittance of the third region differently, it is preferable that a slit pattern smaller than the resolution of the translucent film or the exposure machine is formed in the photomask.

The lower conductive layer pattern may further include an auxiliary gate pad electrically connected to the gate line and an auxiliary data pad electrically connected to the data line.

On the thin film transistor substrate completed through the manufacturing method according to the present invention, a lower conductive layer pattern including the pixel electrode of the pixel portion is formed on the substrate, and has a gate line and a gate electrode connected to the gate line thereon. An upper conductive film pattern including a gate wiring is formed. A gate insulating film pattern covering the gate wiring is formed on the substrate, and a semiconductor pattern is formed on the gate insulating film pattern of the gate electrode. In addition, a data line defining the pixel portion intersecting the gate line, a source electrode connected to the data line and separated from the source electrode and the source electrode extending over the semiconductor pattern on the upper portion of the substrate, and is aligned with the source electrode with respect to the gate electrode. The data wiring including the drain electrode located in the side is formed.

The lower conductive layer pattern may further include an auxiliary gate pad electrically connected to the gate line to receive a gate signal from the outside, and an auxiliary data pad electrically connected to the data line to receive an image signal from the outside.

The lower conductive layer pattern and the upper conductive layer pattern except for the pixel electrode, the auxiliary gate pad, and the auxiliary data pad may have the same shape, and the lower conductive layer pattern may be made of a transparent conductive material.

Next, a thin film transistor array substrate and a method of manufacturing the same according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the present invention.

First, referring to FIGS. 1 and 2, the structure of the unit pixel and the pad of the thin film transistor array substrate for a liquid crystal display device completed using the three masks according to the exemplary embodiment of the present invention will be described in detail.

1 is a layout view of a thin film transistor array substrate for a 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 array substrate illustrated in FIG. 1 taken along the line II-II ′.

First, an aluminum series having low resistance and formed on the lower conductive layer pattern and the lower conductive layer pattern made of a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO) on the insulating substrate 10. An upper conductive film pattern including a silver-based conductive film is formed. The lower conductive layer pattern may be connected to one end of the pixel electrode 20, the auxiliary gate line 22 extending in the horizontal direction, and the auxiliary gate line 22 to receive a gate or scan signal from an external driving circuit, thereby providing a subsequent gate line ( An auxiliary gate line 24 having an auxiliary gate pad 24 and an auxiliary gate electrode 26 connected to the auxiliary gate line 22 to be transferred to the auxiliary gate line 24 and an image signal from an external driving circuit receives data signals 72. Auxiliary data pad 28 is delivered to The upper conductive layer pattern includes a gate line 32 formed in the same shape on the auxiliary gate line 22 as a gate line, and a gate electrode 36 of the thin film transistor connected to the gate line 32. .

Here, the gate wirings 32 and 36, which are upper conductive film patterns, are preferably formed of a single aluminum-based film, but may be formed of two or more layers. In the case of forming more than two layers, it is preferable that one layer is formed of a material having a low resistance and the other layer is made of a material having good contact properties with other materials such as chromium series or molybdenum series. Examples thereof include Al (or Al alloy) / Cr or Al (or Al alloy) / Mo and the like.

A gate insulating layer 42 made of silicon nitride (SiN _x ) and the like is formed on the gate lines 32 and 36 to cover the gate lines 32 and 36. Here, the gate insulating film 42 is removed from the pad portion in which the plurality of pads 24 and 28 are formed and the pixel portion in which the pixel electrode 20 is formed.

A semiconductor pattern 52 made of a semiconductor such as hydrogenated amorphous silicon is formed on the gate insulating layer 42 of the gate electrode 36, and an n type such as phosphorus (P) is formed on the semiconductor pattern 52. An ohmic contact layer pattern or intermediate layer patterns 65 and 66 made of amorphous silicon doped with impurities at a high concentration are formed. Here, the semiconductor pattern 52 is formed only on the upper portion of the gate electrode 36, but may be formed in a pattern having various shapes to prevent the data lines 72, 75, and 76 from being disconnected.

On the resistive contact layer patterns 65 and 66 or the substrate 10, data wirings including an aluminum-based conductive film having low resistance are formed. The data line is formed in a vertical direction to define the gate line 32 and the pixel portion, and extends to an upper portion of the auxiliary data pad 28 to electrically connect the auxiliary data pad 28 to the data line 72. A data line portion consisting of a source electrode 75 of the thin film transistor connected to the line 72, and also separated from the data line portions 72 and 75, and opposite to the source electrode 75 with respect to the gate electrode 36. Also included is a drain electrode 76 of the thin film transistor located at.

The data lines 72, 75, and 76 may be formed of a single layer like the gate lines 32, 36, but may also be formed of a double layer containing chromium, molybdenum, or molybdenum alloy.

In this case, the contact layer patterns 65 and 66 lower the contact resistance between the lower semiconductor pattern 52 and the upper data lines 75 and 76.

Next, a method of manufacturing a thin film transistor substrate for a liquid crystal display device having the structure of FIGS. 1 and 2 using three masks will be described in detail with reference to FIGS. 1 and 2 and FIGS. 3A to 8. .

First, as shown in FIGS. 3A to 3B, the pixel electrode material, such as ITO or IZO, and the low resistance gate wiring conductive material, such as aluminum, are sequentially stacked on the substrate 10, and the photo using the first mask. The lower conductive layer pattern including the pixel electrode 20, the auxiliary gate line 22, the auxiliary gate pad 24, the auxiliary gate electrode 26, and the auxiliary data pad 28 on the substrate 10 by an etching process, and A gate wiring including the gate line 32, a gate electrode 36, and a gate pad 34 and an upper conductive layer pattern including the pixel electrode buffer layer 30 are formed in the same shape.

Next, as shown in FIG. 4, the gate insulating film 40, the semiconductor layer 50, and the intermediate layer 60 are respectively 1,500 mV to 5,000 mV, 500 mV to 2,000 mV, 300 mV to 600 m by chemical vapor deposition. Continuous deposition is carried out at a thickness of 8 mm, and the photosensitive film 110 is applied thereon at a thickness of 1 µm to 2 µm.

Thereafter, the photoresist film 110 is irradiated with light through a second mask and then developed to form the photoresist patterns 112 and 114 as shown in FIG. 5B. At this time, the first portion 114 of the photoresist patterns 112 and 114 positioned on the gate wirings 32 and 36 and located in the portion C where the gate insulating layer pattern 42 (see FIG. 2) is to be formed is a semiconductor pattern. 52 (see FIG. 2) is formed to have a thickness smaller than that of the second portion A positioned above the gate electrode 36, and the photosensitive film of the other portion B is removed. At this time, the ratio of the thickness of the photosensitive film 114 remaining in the channel portion C and the thickness of the photosensitive film 112 remaining in the semiconductor pattern portion A may be adjusted differently according to the process conditions in the etching process, which will be described later. have.

As such, there may be various methods of varying the thickness of the photoresist layer according to the position. In order to control the light transmittance in the C region, a slit or lattice-shaped pattern is mainly formed or a translucent film is used.

In this case, the line width of the pattern located between the slits, or the interval between the patterns, that is, the width of the slits, is preferably smaller than the resolution of the exposure apparatus used for exposure. A thin film having a thickness or a thin film may be used.

When the light is irradiated to the photosensitive film through such a mask, the polymers are completely decomposed at the part directly exposed to the light, and the polymers are not completely decomposed because the amount of light is small at the part where the slit pattern or the translucent film is formed. In the area covered by, the polymer is hardly decomposed. Subsequently, when the photoresist film is developed, only a portion where the polymer molecules are not decomposed is left, and a thin photoresist film may be left at a portion where the light is not irradiated at a portion less irradiated with light. In this case, if the exposure time is extended, all molecules are decomposed, so it should not be so.

Subsequently, etching is performed on the photoresist pattern 114 and the lower layers thereof, that is, the intermediate layer 60, the semiconductor layer 50, and the gate insulating layer 40. In this case, the semiconductor pattern and the lower layers thereof remain in the A region, only the gate insulating layer remains in the C region, and all three layers 60, 50, and 40 are removed in the remaining B region, thereby removing the substrate 10. ), The pad portion and the pixel portion should be exposed.

First, as shown in FIG. 6, the exposed intermediate layer 60, the semiconductor layer 50, and the gate insulating layer 30 below the other portion B are formed by using the photoresist patterns 112 and 114 as etch masks. Etch in turn.

In this way, as shown in FIG. 6, the gate insulating film pattern 42 covering the gate wirings 32 and 36 except for the gate pad 34 is completed, and the semiconductor layer 54 and the intermediate layer pattern 64 are also formed thereon. Formed in the same shape. In the region B, the intermediate layer 60, the semiconductor layer 50, and the gate insulating layer 30 thereunder are removed to expose the upper conductive layer patterns 30, 34, and 38, and the lower conductive layer patterns 20, 24, and 28. . In this case, when dry etching is used, the photoresist patterns 112 and 114 are also etched to a certain thickness.

Subsequently, ashing removes photoresist residue remaining on the surface of the C region.

Next, using the photoresist pattern 112 of the second portion as an etch mask, the intermediate layer 64 exposed in the C region and the lower semiconductor layer 54 are etched and removed. This completes the semiconductor pattern 52 and the intermediate layer pattern 62 as shown in FIG.

Finally, the second photoresist layer 112 remaining on the semiconductor pattern 52 is removed.

5A and 8, the upper conductive layer patterns 30, 34, and 38, which are not covered by the gate insulating layer pattern 42, are removed through the entire surface etching to expose the pixel electrode 20 in the pixel portion. The auxiliary gate pad 24 and the auxiliary data pad 28 are exposed in the pad portion.

Thus, the semiconductor pattern 52 and the gate insulating film pattern 42 are completed, the electrically conductive film for data wiring containing molybdenum-type aluminum-type metal is laminated | stacked, and it patterned by the photolithography process using a 3rd mask, and the gate line 32 is carried out. And a source line 75 and a source electrode 75 intersecting each other and connected to the auxiliary data pad 28 and connected to the data line 72 and extending to an upper portion of the gate electrode 36. And a data line including a drain electrode 76 facing the source electrode 76 with respect to the gate electrode 36.

Subsequently, the doped amorphous silicon layer pattern 62, which is not covered by the data wires 72, 75, and 76, is etched and separated from both sides around the gate electrode 36, while both doped amorphous silicon layers 65, The semiconductor layer pattern 52 between 66 is exposed. Subsequently, in order to stabilize the surface of the exposed semiconductor pattern 52, it is preferable to perform oxygen plasma.

In the thin film transistor array substrate and the method of manufacturing the same according to the embodiment of the present invention, the gate insulating layer pattern is formed by forming the gate wiring and the pixel electrode by a photolithography process using one mask and exposing the pad by a photolithography process using one mask. By forming the semiconductor pattern together with the semiconductor pattern, the thin film transistor substrate may be completed using only three masks to simplify the manufacturing process.

As such, in the present invention, the manufacturing cost can be minimized by simplifying the manufacturing process.

Claims (14)

Stacking and patterning a conductive material for a pixel electrode and a conductive material for a gate wiring on an insulating substrate in order to form a lower conductive film pattern including a pixel electrode and an upper conductive film pattern including a gate line having a gate line and a gate electrode. , Forming a gate insulating layer pattern covering the gate wiring; Forming a semiconductor pattern on the gate insulating layer pattern; Removing the upper conductive layer pattern not covered by the gate insulating layer pattern; Patterning the conductive material for data wiring to form a data wiring including a data line, a source electrode connected to the data line, and a drain electrode separated from the source electrode; And forming the gate insulating layer pattern and the semiconductor pattern by a photolithography process using a photoresist pattern having a different thickness. In claim 1, The photoresist pattern may include a thin film transistor including a first part having a first thickness, a second part having a second thickness thicker than the first thickness, and a third part having little thickness and excluding the first and second parts. Method of manufacturing an array substrate. In claim 2, And forming the second portion corresponding to the semiconductor pattern and the first portion corresponding to the gate insulating layer pattern in the photolithography process. In claim 3, And forming a resistive contact layer pattern between the data line and the semiconductor pattern. In claim 4, The gate insulating layer pattern, the semiconductor pattern and the ohmic contact layer pattern forming step, Sequentially depositing a gate insulating film, a semiconductor layer, and an ohmic contact layer on the substrate; Forming a photoresist film on the ohmic contact layer; Exposing and developing the photoresist to form the photoresist pattern; Etching the gate insulating film, the semiconductor layer, and the ohmic contact layer using the photoresist patterns of the first and second portions as an etching mask to complete the gate insulating film pattern; And etching the semiconductor layer and the ohmic contact layer using the photoresist pattern of the second portion as an etch mask to complete the semiconductor pattern and the ohmic contact layer pattern. In claim 5, And etching the resistive contact layer pattern not covered by the data line. In claim 1, In the photolithography process, the photoresist pattern is formed using a photomask including a first region, a second region having a lower transmittance than the first region, and a third region having a higher transmittance than the first region. Method of manufacturing an array substrate. In claim 7, A method of manufacturing a thin film transistor array substrate having a slit pattern smaller than the resolution of a translucent film or an exposure machine is formed in the photomask to differently control the transmittance of the first to third regions. In claim 1, The lower conductive layer pattern may further include an auxiliary gate pad electrically connected to the gate line and an auxiliary data pad electrically connected to the data line. In claim 1, A method of manufacturing a thin film transistor array substrate further comprising the step of oxygen plasma processing the semiconductor pattern. Board, A lower conductive layer pattern formed on the substrate and including a pixel electrode of the pixel unit; An upper conductive layer pattern formed on the lower conductive layer pattern and including a gate line having a gate line and a gate electrode connected to the gate line; A gate insulating film pattern covering the gate wiring; A semiconductor pattern formed on the gate insulating layer pattern of the gate electrode; A data line formed on the substrate and defining the pixel portion crossing the gate line, a source electrode connected to the data line and extending from the semiconductor pattern, and separated from the source electrode; A data line comprising a drain electrode opposite the source electrode Thin film transistor array substrate comprising a. In claim 11, The lower conductive layer pattern may further include an auxiliary gate pad electrically connected to the gate line to receive a gate signal from the outside, and an auxiliary data pad electrically connected to the data line to receive an image signal from the outside; In claim 12, The lower conductive film pattern and the upper conductive film pattern except for the pixel electrode, the auxiliary gate pad, and the auxiliary data pad are formed in the same shape. In claim 11, The lower conductive layer pattern is a thin film transistor array substrate made of a transparent conductive material.