KR20040039985A - Thin transistor film substrate and method of manufacturing the same - Google Patents

Abstract

PURPOSE: A thin film transistor substrate and a manufacturing method thereof are provided to enhance an electric contact characteristic between the drain electrode and the pixel electrode of the thin film transistor. CONSTITUTION: A plurality of unit cells are arranged regularly on the thin film transistor substrate(200). The unit cell is encircled by a gate line and a data line. The thin film transistor substrate comprises a transparent substrate(210), a thin film transistor(220) formed on the substrate(210), an organic insulation film(230) formed on the substrate(210) for protecting the thin film transistor(220) and a pixel electrode(240) provided on the organic insulation film(230). By ultraviolet(UV) rays, a partial region of the drain electrode(226) of the thin film transistor(220), as the lower potion of the organic insulation film(230), is exposed and developed and then a contact hole(235) with a second step portion(H2) is formed.

Description

Thin Film Transistor Substrate and Method for Manufacturing the Same {THIN TRANSISTOR FILM SUBSTRATE AND METHOD OF MANUFACTURING THE SAME}

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 and a method of manufacturing the same that can improve the electrical contact between the drain electrode and the pixel electrode of the thin film transistor.

1 is a view for explaining a general thin film transistor substrate.

Referring to FIG. 1, the thin film transistor substrate 10 may include a substrate 20, a plurality of thin film transistors 30 provided on the substrate 20, and an organic insulating layer 40 provided on the thin film transistor 30. ).

The thin film transistor 30 is sequentially stacked on a gate electrode 31 branched from a gate line (not shown), a gate red film 32 stacked on the gate electrode 31, and the gate insulating film 32. And a source electrode 35 and a drain electrode 36 branched from a data line (not shown) perpendicular to the gate line.

The organic insulating layer 40 is an insulating layer for protecting the thin film transistor 30 and has a contact hole 50 exposing a portion of the drain electrode 36 of the thin film transistor 30.

On the organic insulating layer 40, a pixel electrode 60 for applying a driving voltage for driving a liquid crystal (not shown) provided on the thin film transistor substrate 10 is provided. Therefore, the pixel electrode 60 is electrically connected to the drain electrode 36 of the thin film transistor 30 through the contact hole 50 of the organic insulating layer 40.

Hereinafter, a process of forming the contact hole 50 will be briefly described.

First, the organic insulating layer 40 is a photosensitive resin in which exposed portions are removed in a developing process, and does not require a separate photoresist, and directly performs a photolithography process on the organic insulating layer 40. Can be.

That is, a mask (not shown) in which a predetermined pattern is formed on the organic insulating layer 40 is aligned, and the organic insulating layer 40 is exposed using the mask. Thereafter, the exposed organic insulating layer 40 is developed using a developer, so that the exposed portion is removed by the developer, and has a first step H1 and a part of the drain electrode 36 of the thin film transistor 30. The contact hole 50 exposing an area is formed.

However, the organic insulating layer 40 is provided on the substrate 20 with a thickness considerably thicker than the overall thickness of the thin film transistor substrate 100. Accordingly, as shown in FIG. 1, in the process of developing the exposed organic insulating layer 40, the developer does not remove all of the exposed organic insulating layers, so that a part of the organic insulating layer exposed on the drain electrode 36 is removed. Will remain.

The residual organic insulating layer causes a disconnection between the pixel electrode 60 and the drain electrode 36 provided on the organic insulating layer 40, and as a result, the pixel is entirely white (high pixel) High Pixel) defects occur.

In addition, the developer does not completely remove the organic insulating layer 40 due to particles or bubbles during the developing process, and thus the organic insulating layer 40 remains on the drain electrode 36. A problem occurs that causes disconnection between the pixel electrode 60 and the drain electrode 36.

Accordingly, the present invention has been made in an effort to solve such a conventional problem, and an object of the present invention is to provide a thin film transistor substrate capable of improving electrical contact between the drain electrode and the pixel electrode of the thin film transistor.

In addition, another object of the present invention is to provide a method for manufacturing the thin film transistor substrate.

1 is a view for explaining a general thin film transistor substrate.

2 is a plan view of a thin film transistor substrate according to an exemplary embodiment of the present invention.

3 is a cross-sectional view of the thin film transistor substrate according to the cutting line I-I illustrated in FIG. 2.

4A to 4D are flowcharts illustrating a manufacturing process of a thin film transistor substrate according to an exemplary embodiment of the present invention.

5 is a plan view of a thin film transistor substrate according to another exemplary embodiment of the present invention.

6 is a partial perspective view illustrating the gate line and the data line shown in FIG. 5.

FIG. 7 is a cross-sectional view of the thin film transistor substrate taken along the cutting line II-II of FIG. 5.

<Description of the code for the main part>

200, 300: thin film transistor substrate 221, 321: gate electrode

222 and 322 gate insulating films 223 and 323 active patterns

224, 324: ohmic contact pattern 225, 325: source electrode

226 and 326 drain electrodes 230 and 330 organic insulating film

235, 335: contact hole 250, 350: gate line

260, 360: data line

According to one aspect of the present invention, a thin film transistor substrate includes: a substrate; A thin film transistor comprising a gate electrode on the substrate, a gate insulating film stacked on the gate electrode, a channel layer provided on the gate insulating film, a source electrode and a drain electrode provided on the channel layer; An organic insulating layer formed on the substrate including the thin film transistor and having a contact hole exposing a portion of the drain electrode; And a pixel electrode provided on the organic insulating layer and electrically connected to the drain electrode through the contact hole, wherein the contact hole includes the gate insulating layer, the channel layer, and the drain electrode sequentially It is formed corresponding to the stacked region.

In addition, a method of manufacturing a thin film transistor substrate according to another aspect for realizing the above object of the present invention comprises: forming a gate line having a gate electrode by patterning a first metal layer formed on the substrate; Forming a gate insulating film on the substrate including the gate line; Forming a channel layer on the gate insulating layer including a region where the gate electrode is formed; Forming a second metal layer on the substrate including the channel layer, and patterning the second metal layer to form a data line having a source electrode and a drain electrode; Forming an organic insulating layer on the substrate including the data line; Forming a contact hole exposing a portion of the drain electrode in the organic insulating layer corresponding to a region in which the gate insulating layer, the channel layer, and the drain electrode are sequentially stacked; And forming a pixel electrode on the organic insulating layer, the pixel electrode electrically connected to the drain electrode through the contact hole.

According to such a thin film transistor substrate and a method of manufacturing the same, the step of forming the contact hole by forming the contact hole by providing the gate insulating film, the channel layer, and the drain electrode under the organic insulating film region where the contact hole is to be formed is performed. The electrical contact between the drain electrode and the pixel electrode can be improved by lowering and removing the residue of the organic insulating film on the drain electrode.

Hereinafter, a thin film transistor 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.

2 is a plan view of a thin film transistor substrate according to an exemplary embodiment, and FIG. 3 is a cross-sectional view of the thin film transistor substrate taken along the cutting line I-I of FIG. 2.

2 and 3, a plurality of unit cells are regularly arranged on the thin film transistor substrate 200 according to an exemplary embodiment of the present invention, and the unit cells may include gate lines ( 250 is surrounded by data line 260.

The thin film transistor substrate 200 includes a transparent substrate 210, a thin film transistor 220 provided on the substrate 210, and an organic layer provided on the substrate 210 to protect the thin film transistor 220. And an insulating layer 230 and a pixel electrode 240 provided on the organic insulating layer 230.

The thin film transistor 220 may cover the gate electrode 221 branched from the gate line 250 extending in the first direction on the substrate 210 and the gate line 221 to protect the gate electrode 221. A gate insulating layer 222 stacked on an entire surface of the substrate 210, a channel layer including an active pattern 223 and an ohmic contact pattern 224 sequentially stacked on the gate insulating layer 222, and the substrate 210. The source electrode 225 and the drain electrode 226 branched from the data line 270 extending in the second direction perpendicular to the first direction.

The organic insulating layer 230 for protecting the thin film transistor 220 is provided on the substrate 210 including the thin film transistor 220 having a predetermined thickness.

The organic insulating layer 230 is a kind of positive photoresist in which the exposed portion is removed in the developing process. The organic insulating layer 230 is exposed to ultraviolet (UV) light through the organic insulating layer 230, and is developed. The contact hole 235 having a second step H2 in the organic insulating layer 230 and exposing a portion of the drain electrode 226 of the thin film transistor 220 provided under the organic insulating layer 230. To form.

In this case, the channel layer stacked on the gate insulating layer 222 is formed of the active pattern 223 and the ohmic contact pattern 224, and the channel layer extends to the lower side of the contact hole 235. In addition, the drain electrode 226 is also provided on the ohmic contact pattern 224, and in particular, extends to a lower side of the contact hole 235. In other words, the gate insulating layer 222, the active pattern 223, the ohmic contact pattern 223, and the drain electrode 226 may be sequentially disposed between the contact hole 235 and the substrate 210. It is provided.

Indium Tin Oxide (ITO) for applying a driving voltage for driving a liquid crystal (not shown) provided on the organic insulating layer 230 on the organic insulating layer 230 provided with the contact hole 235. ) Or an indium tin zinc (hereinafter referred to as IZO) pixel electrode 240 is electrically connected to the drain electrode 226 of the thin film transistor 220.

As such, the contact hole 235 is provided under the contact hole 235 by providing the gate insulating layer 222, the active pattern 223, the ohmic contact pattern 223, and the drain electrode 226. The second step H2 can be smaller than the step of the conventional contact hole.

4A to 4D are flowcharts illustrating a method of manufacturing a thin film transistor substrate according to an exemplary embodiment of the present invention.

First, referring to FIG. 4A, aluminum (Al), molybdenum (Mo), chromium (Cr), tantalum (Ta), titanium (Ti), copper (Cu), tungsten (W), etc. may be disposed on a transparent substrate 210. The same first metal layer is deposited. Subsequently, the first metal layer is patterned to form a gate line (not shown) in which the gate electrode 221 is branched.

In order to protect the gate line on the resultant, silicon nitride (SiNx) is deposited by a plasma chemical vapor deposition method to form a gate insulating film 222.

Referring to FIG. 4B, an amorphous silicon film and an n ⁺ amorphous silicon film doped in-situ are sequentially stacked on the gate insulating film 222 by a plasma chemical vapor deposition method. Next, an active pattern 223 and an ohmic contact pattern 224 are sequentially formed on the gate insulating layer 222 by patterning the stacked amorphous silicon film and the n ⁺ amorphous silicon film.

In this case, the amorphous silicon film and the n ⁺ amorphous silicon film are patterned such that the active pattern 223 and the ohmic contact pattern 224 are provided at one side of the gate electrode 221, that is, at the position where the contact hole is to be formed. . As a result, as shown in FIG. 4B, the active pattern 223 and the ohmic contact pattern 224 extending to the right side of the gate electrode 221 are formed.

Referring to FIG. 4C, a second metal layer made of chromium (Cr) or other metal having low contact resistance and excellent adhesion to the n ⁺ amorphous silicon film is stacked on the resultant. Thereafter, the second metal layer is patterned to form a data line perpendicular to the gate line.

The data line formed by patterning the second metal layer includes a source electrode 225 and a drain electrode 226 branched from the data line. In other words, the source electrode 225 and the drain electrode 226 branched from the data line are formed above the gate electrode 221 branched from the gate line.

The drain electrode 226 extends to the right side of the gate electrode 221 like the active pattern 223 and the ohmic contact pattern 224 as shown in FIG. It is formed on the active pattern 223 and the ohmic contact pattern 224 extending to the right. As a result, the thin film transistor 220 is completed on the substrate 210.

Referring to FIG. 4D, the photosensitive organic insulating layer 230 having a predetermined thickness is coated on the entire surface of the substrate 210 including the thin film transistor 220.

As described with reference to FIG. 3, the organic insulating layer 230 is a kind of positive photoresist in which the exposed portions are removed in the developing process, and the photoresist is not coated on the organic insulating layer 230. Lithography (phtolithography) process can be performed.

Subsequently, the organic insulating layer 230 is exposed and developed to expose the gate insulating layer 221 and the active pattern 223 on the right side of the gate electrode 221, that is, on the substrate 210, as shown in FIG. 4D. And a contact hole 235 having the second step H2 in a region in which the ohmic contact pattern 224 and the drain electrode 226 are sequentially stacked, and exposing a predetermined region of the drain electrode 226. To form.

Thereafter, the pixel electrode 240 made of ITO or IZO is formed on the organic insulating layer 230 on which the contact hole 235 is formed. This completes the thin film transistor substrate 200 shown in FIG.

Thus, the gate insulating layer 222, the active pattern 223, the ohmic contact pattern 224, and the drain electrode 226 are sequentially formed between the substrate 210 and the contact hole 235. By lowering the second step H2 of the contact hole 235 and completely removing the exposed organic insulating layer 230 formed on the drain electrode 226 in the developing process, the drain electrode 226 and The electrical contact force with the pixel electrode 240 may be improved.

5 is a plan view of a thin film transistor substrate according to another exemplary embodiment of the present invention, FIG. 6 is a partial perspective view illustrating a gate line and a data line shown in FIG. 5, and FIG. 7 is a cut line II illustrated in FIG. 5. A cross-sectional view of the thin film transistor substrate according to -II.

5 to 7, a plurality of unit cells are regularly arranged on the thin film transistor substrate 300 according to another embodiment of the present invention, and the unit cell is a gate line. Surrounded by 350 and data line 360.

The thin film transistor substrate 300 may have a predetermined thickness on the transparent substrate 310, the thin film transistor 320 provided on the substrate 310, and the thin film transistor 320 to protect the thin film transistor 320. It includes an organic insulating film 330 provided with a and a pixel electrode 340 provided on the organic insulating film 330.

The thin film transistor 320 is branched from the gate line 321 and the gate line 350 branched from the gate line 350 extending in the first direction on the substrate 310 and the gate electrode 321. It is provided on the same plane, and provided with a protruding pad 321a spaced apart from the gate electrode 321 by a predetermined interval. However, the gate electrode 321 and the protruding pad 321a may be integrally provided from the gate line 350.

In order to protect the gate electrode 321 and the protruding pad 321a, the gate insulating layer 322 stacked on the entire surface of the substrate 310, and the active pattern 323 sequentially stacked on the gate insulating layer 322. A source electrode 325 and a drain electrode 326 branched from an ohmic contact pattern 324 and a data line 370 extending in a second direction perpendicular to the first direction on the substrate 310.

In this case, the active pattern 323 and the ohmic contact pattern 324 stacked on the gate insulating layer 322 extend to the upper region of the protruding pad 321a.

In addition, the drain electrode 326 also extends to an upper region of the protruding pad 321a of the gate line 350. Accordingly, the gate insulating layer 322, the active pattern 323, the ohmic contact pattern 324, and the drain electrode 326 are sequentially stacked on the protruding pad 321a.

The organic insulating layer 330 is provided on the thin film transistor 320 to protect the thin film transistor 320. A contact hole 335 having a third step H3 on the organic insulating layer 330 and exposing a portion of the drain electrode 326 of the thin film transistor 320 provided under the organic insulating layer 330. Is formed.

On the organic insulating layer 330 on which the contact hole 335 is formed, a pixel electrode 340 for applying a driving voltage for driving a liquid crystal (not shown) provided on the organic insulating layer 330 is provided. The pixel electrode 340 is made of ITO or IZO, is provided on an upper surface of the organic insulating layer 330, and is electrically connected to the drain electrode 326 through the contact hole 335.

As such, the protruding pad 321a branched from the gate line 350 between the substrate 310 and the contact hole 335, the gate insulating layer 222, the active pattern 223, and the ohmic. The contact pattern 223 and the drain electrode 226 may be sequentially provided so that the third step H3 of the contact hole 235 may be smaller than that of the conventional contact hole.

Hereinafter, a manufacturing process of the thin film transistor substrate will be described with reference to FIG. 7. However, the same process as the manufacturing process of the thin film transistor substrate according to the exemplary embodiment described above will be omitted.

First, a first metal layer is deposited on the substrate 310 and patterned to form a gate line 350 extending in the first direction. The gate line 350 is provided on the same plane and spaced apart from each other by the gate electrode 321 and the protruding pad 321a in the patterning process. However, the gate electrode 321 and the protruding pad 321a may be integrally formed from the gate line 350.

Thereafter, in order to protect the gate line 350, silicon nitride (SiNx) is stacked on the resultant to form a gate insulating film 322.

An active pattern 323 and an ohmic contact pattern 324 are formed on the gate insulating layer 322 as described with reference to FIGS. 4B through 4D, and the data line 360 extends in a direction perpendicular to the gate line. The branched source electrode 325 and the drain electrode 326 are formed. Thus, the thin film transistor 320 is completed on the substrate 310.

In this case, the active pattern 323, the ohmic contact pattern 324, and the drain electrode 326 are formed on the right side of the gate electrode 321 to extend to the upper side of the protruding pad 321a.

Subsequently, the photosensitive organic insulating layer 330, which is a kind of a positive photoresist, is coated on the substrate 310 including the thin film transistor 320 to a predetermined thickness. .

The organic insulating layer 330 provided above the region in which the protruding pad 321a, the gate insulating layer 322, the active pattern 323, the ohmic contact pattern 324, and the drain electrode 326 are sequentially stacked. ), A portion of the drain electrode 326 is exposed, and a contact hole having a third step H3 is formed.

Thereafter, a pixel electrode 340 is formed on the resultant to apply a driving voltage for driving a liquid crystal (not shown) provided above the organic insulating layer 330. The pixel electrode 340 is made of ITO or IZO and is electrically connected to the drain electrode 326 exposed by the contact hole 330. This completes the thin film transistor substrate 300 shown in FIG.

Thus, the gate insulating layer 322, the active pattern 323, the ohmic contact pattern 324, and the drain electrode 326 are sequentially formed between the substrate 310 and the contact hole 335. By lowering the third step H3 of the contact hole 335 and completely removing the exposed organic insulating layer 330 formed on the drain electrode 326 in the development process, The electrical contact force with the pixel electrode 340 may be improved.

It is apparent that the thin film transistor substrate described above may be applied to all of the thin film transistor substrates provided in the transmissive, reflective and reflective-transmissive liquid crystal display devices.

Although described with reference to the embodiments above, those skilled in the art will understand that the present invention can be variously modified and changed without departing from the spirit and scope of the invention as set forth in the claims below. Could be.

As described above, according to the present invention, an active pattern, an ohmic contact pattern, and a drain electrode of a thin film transistor are provided on the substrate to extend to the contact hole lower region of the organic insulating layer. The step can be reduced.

In addition, the stepped portion of the contact hole may be further reduced by the thickness of the protruding pad by further including a protruding pad branched from the gate line under the gate insulating layer corresponding to the contact hole.

As described above, in the exposure and development processes for forming the contact hole in the organic insulating layer by reducing the step difference of the contact hole, the organic insulating layer is prevented from remaining without being removed on the drain electrode, thereby preventing the drain electrode and the organic. Electrical contact between the pixel electrode provided on the insulating layer may be improved, and high pixel defects due to disconnection between the drain electrode and the pixel electrode may be prevented.

Claims (4)

Board; A thin film transistor comprising a gate electrode on the substrate, a gate insulating film stacked on the gate electrode, a channel layer provided on the gate insulating film, a source electrode and a drain electrode provided on the channel layer; An organic insulating layer formed on the substrate including the thin film transistor and having a contact hole exposing a portion of the drain electrode; And A pixel electrode provided on the organic insulating layer and electrically connected to the drain electrode through the contact hole; The contact hole may be formed to correspond to a region in which the gate insulating layer, the channel layer, and the drain electrode are sequentially stacked to reduce the step difference. 2. The protrusion of claim 1, wherein the protrusion is branched from a metal line having the gate electrode between the substrate and the gate insulating layer to correspond to the contact hole, and is provided on the same plane as the gate electrode and spaced apart from the gate electrode by a predetermined distance. The thin film transistor substrate of claim 1, further comprising a pad to reduce the step difference of the contact hole by the height of the protruding pad. Patterning a first metal layer formed on the substrate to form a gate line having a gate electrode; Forming a gate insulating film on the substrate including the gate line; Forming a channel layer on the gate insulating layer including a region where the gate electrode is formed; Forming a second metal layer on the substrate including the channel layer, and patterning the second metal layer to form a data line having a source electrode and a drain electrode; Forming an organic insulating layer on the substrate including the data line; Forming a contact hole exposing a portion of the drain electrode in the organic insulating layer corresponding to a region in which the gate insulating layer, the channel layer, and the drain electrode are sequentially stacked; And Forming a pixel electrode electrically connected to the drain electrode through the contact hole on the organic insulating layer. The method of claim 3, wherein the forming of the gate line comprises: Forming a gate line from the first metal layer on the same plane as the gate electrode and corresponding to the contact hole, and having a protruding pad spaced apart from the gate electrode by a predetermined distance from the first metal layer; Method of manufacturing a thin film transistor substrate.