KR20080043092A - Thin film transistor substrate and manufacturing method of the same - Google Patents

Abstract

A thin film transistor substrate and a method for manufacturing the thin film transistor substrate are provided to form a passivation layer on a thin film transistor using organic material to prevent reduction of zinc oxide, maintain current and voltage characteristics of a zinc oxide semiconductor and insulate the thin film transistor from a pixel electrode. A thin film transistor substrate includes a gate line(14), a data line(24), a thin film transistor, a pixel electrode(42), and an organic passivation layer. The gate line and the data line formed on a substrate crossing each other to define a pixel region. The thin film transistor is connected to the gate line and the data line and includes a zinc oxide semiconductor. The pixel electrode is connected to the thin film transistor. The organic passivation layer is formed between the thin film transistor and the pixel electrode and made of siloxane or BCB(Benzocyclobutene).

Description

Thin film transistor substrate and its manufacturing method {THIN FILM TRANSISTOR SUBSTRATE AND MANUFACTURING METHOD OF THE SAME}

1 is a plan view illustrating a thin film transistor substrate according to a first exemplary embodiment of the present invention.

FIG. 2 is a cross-sectional view illustrating a thin film transistor substrate cut along the line II ′ shown in FIG. 1.

3 is a cross-sectional view illustrating a thin film transistor substrate according to a second exemplary embodiment of the present invention.

4 is a flowchart illustrating a method of manufacturing a thin film transistor substrate according to an exemplary embodiment of the present invention.

5A through 5E are cross-sectional views illustrating a method of manufacturing a thin film transistor substrate according to an exemplary embodiment of the present invention.

6A and 6B are cross-sectional views illustrating a method of manufacturing a thin film transistor substrate according to a second exemplary embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

10 substrate 12 gate electrode

14 gate line 18 gate insulating film

20: active layer 22: nitrogen film

24: data line 26: source electrode

28: drain electrode 38, 39: organic protective film

40: contact hole 42: pixel electrode

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 on which a protective film is formed so that the characteristics of an oxide semiconductor are maintained.

In general, a liquid crystal display (LCD) displays an image by allowing each of the liquid crystal cells arranged in a matrix form on a liquid crystal panel to adjust light transmittance according to a video signal. Here, the liquid crystal panel includes a thin film transistor substrate and a color filter substrate facing each other with the liquid crystal interposed therebetween.

In the liquid crystal panel, the liquid crystal cell is positioned in an area defined by the intersection of the gate line and the data line. Each of the liquid crystal cells is formed with a pixel electrode to which a pixel data voltage is applied and a common electrode to which a common voltage is applied. In the liquid crystal cells, thin film transistors connected to the gate line, the data line, and the pixel electrode are formed to supply the pixel voltage supplied to the data line to the pixel electrode whenever the scan signal is supplied to the gate line, thereby displaying an image. .

Here, the thin film transistor is a plasma enhanced chemical vapor deposition (PECVD) process to protect the back gate of the bottom gate structure after forming the source and drain electrodes when the semiconductor layer is formed of a zinc oxide (ZnO) -based oxide semiconductor Form. Here, the PECVD process uses SiH 4, NH 3, H 2, or the like as the reaction gas. At this time, in the zinc oxide oxide semiconductor, oxygen molecules of the oxide are reduced by the reaction gas of the PECVD process. The zinc oxide oxide semiconductor is formed by O 2 in the semiconductor. The characteristics rapidly change according to the quantity, and the performance of the thin film transistor is also degraded.

Accordingly, an aspect of the present invention is to provide a thin film transistor substrate having a protective film formed thereon so as to maintain voltage and current characteristics of a zinc oxide oxide semiconductor, and a method of manufacturing the same.

In order to achieve the above technical problem, the present invention is formed in a cross-structure on the substrate and connected to the gate line and data line defining the pixel region, the gate line and the data line, and comprises a zinc oxide oxide semiconductor Thin film transistor; Provided is a thin film transistor substrate including a pixel electrode connected to the thin film transistor and an organic protective film formed between the thin film transistor and the pixel electrode and formed of any one of a siloxane series and a benzocyclobutene.

The thin film transistor may include a gate electrode formed on the substrate; A gate insulating film formed on the gate electrode; An active layer formed of a zinc oxide oxide semiconductor on the gate insulating layer; A source electrode and a drain electrode in contact with the active layer.

In order to achieve the above technical problem, the present invention is a gate line and a data line formed on the substrate to cross each other to define a pixel region; A gate electrode connected to the gate line, a gate insulating film formed on the gate electrode, an active layer formed of zinc oxide oxide semiconductor on the gate insulating film, the active layer, a nitrogen film formed on the active layer, and a source formed on the nitrogen film A thin film transistor including an electrode and a drain electrode; A thin film transistor substrate is formed between a pixel electrode connected to the thin film transistor and an organic protective film formed between the thin film transistor and the pixel electrode.

Here, the nitrogen film is formed through the nitrogen (N2) plasma in the active layer.

In order to achieve the above technical problem, the present invention comprises the steps of forming a gate line and a data line formed on the substrate to cross each other to define a pixel region; Forming a thin film transistor connected to the gate line and the data line and including a zinc oxide oxide semiconductor; Forming a pixel electrode connected to the thin film transistor; and forming an organic protective film formed between the thin film transistor and the pixel electrode and formed of any one of siloxane-based and benzocyclobutene. To provide.

The forming of the thin film transistor may include forming a gate electrode connected to the gate line; Forming a gate insulating film on the gate electrode; Forming an active layer formed of a zinc oxide oxide semiconductor on the gate insulating layer, and forming a source electrode and a drain electrode in contact with the active layer.

In order to achieve the above technical problem, the present invention comprises the steps of forming a gate line and a data line formed on the substrate to cross each other to define a pixel region; Forming a gate electrode connected to the gate line; Forming a gate insulating film on the gate electrode; Forming an active layer formed of a zinc oxide oxide semiconductor on the gate insulating film; Forming a nitrogen film on the active layer through a nitrogen (N2) plasma process; Forming a source electrode and a drain electrode in contact with the active layer; It provides a method of manufacturing a thin film transistor substrate comprising the step of forming a pixel electrode connected to the drain electrode and the organic protective film formed of an acryl-based under the pixel electrode.

The forming of the organic passivation layer may further include forming a contact hole connecting the drain electrode and the pixel electrode.

Other objects and features of the present invention in addition to the above object will become apparent from the description with reference to the accompanying drawings.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to FIGS. 1 to 5E. In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity.

1 is a plan view illustrating a thin film transistor substrate according to a first exemplary embodiment of the present invention, and FIG. 2 is a cross-sectional view illustrating a cross section of the thin film transistor substrate cut along the line II ′ shown in FIG. 1.

1 and 2, the thin film transistor substrate according to the present invention is formed on the substrate 10 in a cross structure with each other to define a gate area 14, a data line 24, and a gate line (defining a pixel area). 14 and a thin film transistor TFT connected to the data line 24 and including a zinc oxide oxide semiconductor, a pixel electrode 42 and a thin film transistor TFT and a pixel electrode connected to the thin film transistor TFT. It is formed between 42), and comprises an organic protective film 38 formed of any one of a siloxane-based and benzocyclobutene (BCB).

Specifically, the thin film transistor substrate is formed on each of the crossing points of the gate line 14 and the data line 24 and the gate line 14 and the data line 24 which are formed to cross each other on the substrate 10. (TFT) and a pixel electrode 42 formed in the pixel region defined by the gate line 14 and the data line 24 and connected to the thin film transistor TFT.

The substrate 10 is formed using an insulating substrate such as transparent glass or plastic.

The gate line 14 supplies a scan signal supplied from the outside to the gate electrode 12 of the thin film transistor TFT. Here, the gate line 14 is formed of a single layer of metals or alloys thereof, such as aluminum, chromium, copper, molybdenum, or the like, or a multi-layer structure composed of a combination thereof.

The data line 24 is formed to intersect the gate line 14 on the gate insulating layer 18 to be described later. The data line 24 has a multi-layered structure in which a metal such as chromium (Cr), aluminum (Al), molybdenum (Mo), silver (Ag), titanium (Ti), or an alloy thereof is formed in a single layer or a combination thereof. Is formed.

The thin film transistor TFT is formed of a gate electrode 12, a gate insulating film 18, an active layer 20, a source electrode 26, and a drain electrode 28.

The gate electrode 12 is formed to be connected to the gate line 14, and the gate electrode 12 is formed to protrude from the gate line 14. The gate electrode 12 turns the thin film transistor TFT on and off using the gate on / off voltage from the gate line 14. The gate electrode 12 is formed on the gate line 14, and is patterned to form a portion protruding from the gate line 14.

The gate insulating layer 18 is formed by depositing a material such as SiNx or SiOx on the gate line 14 and the gate electrode 12, and insulates the gate line 14 and the gate electrode 12 from other conductive layers. .

The active layer 20 is formed of a zinc oxide oxide semiconductor to form a channel of the thin film transistor TFT. In this case, the zinc oxide oxide semiconductor is formed by depositing by sputtering or metal organic chemical vapor deposition (MOCVD). The zinc oxide oxide is formed of an oxide such as zinc (Zn), indium (In), gallium (Ga), tin (Sn), or a combination thereof.

The source electrode 26 is formed to protrude from one side of the data line 24 of the same material as the data line 24. The source electrode 26 supplies the data voltage from the data line 24 to the drain electrode 28 via the channel of the thin film transistor TFT when the thin film transistor TFT is turned on.

The drain electrode 28 is formed to face the source electrode 26 with the same material as the data line 24. The drain electrode 28 supplies the data voltage transmitted from the source electrode 26 to the pixel electrode 42.

The pixel electrode 42 is connected to the drain electrode 28 of the thin film transistor TFT through the contact hole 40 and is formed on the organic passivation layer 38 to be described later. Here, the pixel electrode 42 is formed of a transparent metal such as indium tin oxide (ITO) or indium zinc oxide (IZO). When the data signal is supplied through the thin film transistor TFT, the pixel electrode 42 forms an electric field with the common electrode to which the common voltage is supplied to drive the liquid crystal molecules arranged above the thin film transistor substrate. In addition, the pixel electrode 42 realizes gray scale by controlling the transmittance of light passing through the pixel region by driving the liquid crystal molecules.

The organic protective layer 38 is positioned between the thin film transistor TFT and the pixel electrode 42 and covers the thin film transistor TFT. The organic protection film 38 protects the thin film transistor TFT and insulates the thin film transistor TFT from the pixel electrode 42. Here, the organic passivation layer 38 is formed of a single organic passivation layer 38 without separately forming an inorganic layer at an interface in contact with the thin film transistor TFT.

The organic protective film 38 is formed of a single layer made of either siloxane or BCB. The organic protective film 38 formed of any one of the siloxane-based and BCB is prevented from being increased in off current due to a chemical reaction while being in contact with the zinc oxide-based oxide semiconductor.

In the organic passivation layer 38, when the gate-off voltage Voff is given in the turn-off operation of the thin film transistor TFT, the off current Ioff is measured to be below an appropriate level, so that the characteristics of the thin film transistor TFT are excellent.

3 is a cross-sectional view illustrating a thin film transistor substrate according to a second exemplary embodiment of the present invention.

Referring to FIG. 3, a thin film transistor substrate according to the present invention may be formed in a cross structure on a substrate 10 to define a gate region 14 and a data line 24, a gate line 14, and a pixel region. The connected gate electrode 12, the gate insulating film 18 formed on the gate electrode 12, the active layer 20 formed of a zinc oxide oxide semiconductor on the gate insulating film 18, and nitrogen (N 2) in the active layer 20. A thin film transistor (TFT) including a nitrogen film 22 formed on the active layer 20 through the plasma, a source electrode 26 and a drain electrode 28 formed on the nitrogen film 22, and a thin film transistor (TFT). And an organic passivation film 39 formed between the pixel electrode 42 and the thin film transistor TFT and the pixel electrode 42, which are connected to each other.

The thin film transistor substrate according to the present invention further includes a nitrogen film 22 formed on the active layer 20 as compared to the thin film transistor substrate shown in FIG. 1. The organic protective film 39 is formed of an acrylic organic material.

Specifically, in the thin film transistor TFT, the nitrogen film 22 formed through the nitrogen (N2) plasma is formed on the active layer 20 formed of the zinc oxide oxide semiconductor. The thin film transistor TFT is pretreated using a nitrogen (N 2) plasma containing no hydrogen to prevent oxygen molecular reduction of the zinc oxide oxide semiconductor constituting the active layer 20. This pretreatment forms a nitrogen film 22 on the surface of the active layer 20 to exhibit the same effect as passivation. Here, the nitrogen film 22 prevents a metal material forming the source electrode 26 and the drain electrode 28 from reacting with the zinc oxide oxide semiconductor to generate a leakage current in the channel of the thin film transistor TFT. Due to the deposition of the acrylic organic protective layer 38, the oxide of the zinc oxide oxide semiconductor is reduced to prevent the characteristics of the thin film transistor TFT from deteriorating.

An acrylic organic protective film 39 is formed on the thin film transistor TFT. Here, the acrylic organic protective film 39 has an effect similar to that of the organic protective film formed of any one of the siloxane-based and BCB described above. Therefore, detailed description will be omitted.

4 is a flowchart illustrating a method of manufacturing a thin film transistor substrate according to an exemplary embodiment of the present invention.

Referring to FIG. 4, the method of manufacturing a thin film transistor substrate according to the present invention may include forming a first conductive pattern group including a gate electrode on the substrate (S1), a gate insulating film covering the first conductive pattern group, and a gate. Forming an active layer formed of a zinc oxide oxide semiconductor on the insulating layer (S2), and forming a second conductive pattern group including a source electrode on the active layer and a drain electrode facing the source electrode and a channel therebetween ( S3), forming a protective film covering the second conductive pattern group with an organic film of any one of acrylic, siloxane, and benzocyclobutenes, and forming a contact hole penetrating the protective film (S4), exposed through the contact hole. Forming a pixel electrode connected to the drain electrode (S5).

Hereinafter, in order to explain in detail the manufacturing method of the thin film transistor substrate according to the present invention will be described step by step with reference to FIGS. 5A to 5E.

5A through 5E are cross-sectional views illustrating a method of manufacturing a thin film transistor substrate according to an exemplary embodiment of the present invention.

Referring to FIG. 5A, a first conductive pattern group including a gate line and a gate electrode 12 is formed on the substrate 10 (S1).

Specifically, the first conductive layer is formed on the substrate 10 through a deposition method such as sputtering. The first conductive layer is formed of a single layer of metals or alloys thereof such as aluminum, chromium, copper and molybdenum or the like, or a multi-layer structure composed of a combination thereof. Subsequently, the first conductive layer is patterned by a photolithography process and an etching process using a mask to form a first conductive pattern group including the gate line and the gate electrode 12.

Referring to FIG. 5B, a gate insulating film 18 and an active layer 20 formed of a zinc oxide oxide semiconductor are sequentially stacked on the substrate 10 having the first conductive pattern group formed thereon (S2).

Specifically, the active layer 20 formed of the gate insulating film 18 and the zinc oxide oxide semiconductor is formed on the substrate 10 on which the gate line and the gate electrode 12 are formed, such as plasma enhanced chemical deposition (PECVD). Lamination is carried out sequentially through a deposition method. Subsequently, the active layer 20 is formed by patterning a zinc oxide oxide semiconductor in a photolithography process and an etching process. At this time, the gate insulating film 18 is formed of an inorganic insulating material such as SiNx, SiOx.

Referring to FIG. 5C, a third conductive pattern group including a data line and a source electrode 26 and a drain electrode 28 formed to face each other on the gate insulating layer 18 is formed (S3).

Specifically, the second conductive pattern group forms a second conductive layer by a sputtering method. After the photoresist is applied onto the second conductive layer, the photoresist pattern is formed by exposing and developing the photoresist in a photolithography process using a slit mask. Here, the blocking region of the slit mask is positioned in the region where the source electrode 26 and the drain electrode 28 are to be formed to block ultraviolet rays, so that a photoresist pattern remains after development, and the slit region of the slit mask is the source electrode 26 and The residual photoresist pattern thinner than the photoresist pattern after development is formed by diffracting ultraviolet rays by being located in the region where the channel of the drain electrode 28 is to be formed. Then, the transmissive region of the slit mask transmits all the ultraviolet rays so that the photoresist is removed after development.

Subsequently, the photoresist pattern is thinned and the remaining photoresist pattern is removed by ashing the ashing process using an ashing process using oxygen plasma or the like. Next, the source electrode 26 and the drain electrode 28 are removed by the etching process using the ashed photoresist pattern, so that the source electrode 26 and the drain electrode 28 are separated, and the active layer 20 is removed. Exposed.

Here, the second conductive layer is formed of a metal such as aluminum, chromium, copper and molybdenum or their alloys in a single layer, or a combination thereof in a multilayer structure.

Referring to FIG. 5D, an organic protective layer 38 having a contact hole 40 is formed on the source electrode 141 and the drain electrode 142 of the second conductive pattern group.

Specifically, the organic protective film 38 is formed on the lower substrate 10 on which the second conductive pattern group is formed through a deposition method such as PECVD or spin coating, and penetrates the organic protective film 38 by a photolithography process and an etching process. As a result, a contact hole 40 exposing the drain electrode 28 is formed. Here, the organic protective film 38 is formed on the upper portion of the second conductive pattern group as a single organic film formed of either siloxane or BCB to prevent oxide reduction of the insulating and zinc oxide oxide semiconductors.

Referring to FIG. 5E, the pixel electrode 42 is formed on the organic passivation layer 38 (S5).

Specifically, the pixel electrode 42 is formed by forming a third conductive layer on the organic protective layer 38 by sputtering or the like, and then patterning the third conductive layer by photolithography and etching. As the third conductive layer, a transparent conductive material such as ITO, IZO, TO (Tin Oxide), or the like is used. The pixel electrode 42 is connected to the drain electrode 28 through the contact hole 40.

6A and 6B are cross-sectional views illustrating a method of manufacturing a thin film transistor substrate according to a second exemplary embodiment of the present invention.

Here, since the process of forming the first conductive pattern group in the method of manufacturing the thin film transistor substrate according to the second embodiment of the present invention is as shown in FIG. 5A, detailed description thereof will be omitted.

Referring to FIG. 6A, a gate insulating film 18 and an active layer 20 formed of a zinc oxide oxide semiconductor are sequentially stacked on a substrate 10 on which a first conductive pattern group is formed. Lamination is sequentially performed through a deposition method such as plasma enhanced chemical deposition (PECVD). Subsequently, the active layer 20 is formed by patterning a zinc oxide oxide semiconductor in a photolithography process and an etching process. At this time, the gate insulating film 18 is formed of an inorganic insulating material such as SiNx, SiOx.

Then, the nitrogen layer 22 is formed on the active layer 20 formed of the zinc oxide oxide semiconductor through a nitrogen (N 2) plasma process.

Next, a second conductive pattern group is formed on the nitrogen film 22. Since the detailed description thereof is the same as the method of forming the second conductive pattern group described in the first embodiment of the present invention, a detailed description thereof will be omitted.

Next, referring to FIG. 6B, an acrylic organic protective film 38 is formed on the second conductive pattern group and the nitrogen film. The acrylic organic protective film 39 is formed of a single organic film. The acrylic organic protective film 39 forms a contact hole 40 exposing the drain electrode 28.

Next, the pixel electrode 42 connected to the drain electrode 28 is formed via the contact hole 40. Here, since the method of forming the pixel electrode 42 is the same as the method of forming the pixel electrode described in the first embodiment of the present invention, a detailed description thereof will be omitted.

As described above, the thin film transistor substrate and the manufacturing method thereof according to the present invention prevent the reduction of the zinc oxide oxide by forming a protective film using an organic film on the thin film transistor. The current and voltage characteristics of the zinc oxide oxide semiconductor are maintained, and the thin film transistor and the pixel electrode are insulated.

Although the detailed description of the present invention described above has been described with reference to a preferred embodiment of the present invention, those skilled in the art or those skilled in the art, those skilled in the art, described in the claims below It will be understood that various modifications and changes can be made in the present invention without departing from the spirit and scope of the invention.

Claims (8)

A gate line and a data line intersecting each other on the substrate to define a pixel area; A thin film transistor connected to the gate line and the data line and including a zinc oxide oxide semiconductor; A pixel electrode connected to the thin film transistor; A thin film transistor substrate formed between the thin film transistor and the pixel electrode, the thin film transistor substrate comprising an organic protective film formed of any one of siloxane-based and benzocyclobutene. According to claim 1, The thin film transistor is A gate electrode formed on the substrate; A gate insulating film formed on the gate electrode; An active layer formed of a zinc oxide oxide semiconductor on the gate insulating layer; A thin film transistor substrate comprising a source electrode and a drain electrode in contact with the active layer. A gate line and a data line intersecting each other on the substrate to define a pixel area; A gate electrode connected to the gate line, a gate insulating film formed on the gate electrode, an active layer formed of zinc oxide oxide semiconductor on the gate insulating film, the active layer, a nitrogen film formed on the active layer, and a source formed on the nitrogen film A thin film transistor including an electrode and a drain electrode; A pixel electrode connected to the thin film transistor; A thin film transistor substrate formed between the thin film transistor and the pixel electrode, the thin film transistor substrate comprising an organic protective film formed of acrylic. The method of claim 3, wherein The nitrogen film is a thin film transistor substrate, characterized in that formed in the active layer through a nitrogen (N2) plasma. Forming a gate line and a data line intersecting each other on the substrate to define a pixel area; Forming a thin film transistor connected to the gate line and the data line and including a zinc oxide oxide semiconductor; Forming a pixel electrode connected to the thin film transistor; And forming an organic protective film formed between the thin film transistor and the pixel electrode and formed of any one of siloxane-based and benzocyclobutene. The method of claim 5, Forming the thin film transistor is Forming a gate electrode connected to the gate line; Forming a gate insulating film on the gate electrode; Forming an active layer formed of a zinc oxide oxide semiconductor on the gate insulating film; Forming a source electrode and a drain electrode in contact with the active layer. Forming a gate line and a data line intersecting each other on the substrate to define a pixel area; Forming a gate electrode connected to the gate line; Forming a gate insulating film on the gate electrode; Forming an active layer formed of a zinc oxide oxide semiconductor on the gate insulating film; Forming a nitrogen film on the active layer through a nitrogen (N2) plasma process; Forming a source electrode and a drain electrode in contact with the active layer; Forming a pixel electrode connected to the drain electrode; A method of manufacturing a thin film transistor substrate comprising forming an organic protective film formed of an acryl-based under the pixel electrode. The method of claim 7, wherein In the step of forming the organic protective film And forming a contact hole connecting the drain electrode and the pixel electrode.

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