KR100476051B1 - A method for manufacturing thin film transistor liquid crystal display - Google Patents

Abstract

The present invention relates to a method of manufacturing a thin film transistor liquid crystal display device which can reduce the process step and simplify the process, the method comprising the steps of forming a gate electrode on the insulating substrate using a first mask, and the front surface including the gate electrode Depositing a gate insulating film, an active layer, a channel layer, and a metal layer for a source / drain electrode, and etching the source / drain electrode metal layer and a channel layer with a second mask, and a protective layer on the resultant layer. Depositing and selectively etching the passivation layer, the active layer and the gate insulating layer using a third mask, and using the fourth mask to connect the upper portion of the passivation layer and the metal layer for the source / drain electrodes. Characterized in that it comprises a step of forming.

Description

Manufacturing method of thin film transistor liquid crystal display device {A METHOD FOR MANUFACTURING THIN FILM TRANSISTOR LIQUID CRYSTAL DISPLAY}

The present invention relates to a method of manufacturing a thin film transistor liquid crystal display device, and more particularly, to a method of manufacturing a thin film transistor liquid crystal display device which can simplify the process by reducing the process step.

In general, liquid crystal displays (LCDs), which are a type of flat panel display, obtain an image with a difference in contrast obtained by changing an optical anisotropy by applying an electric field to a liquid crystal having both liquidity and optical properties of a crystal. Device.

According to the type of liquid crystal used, TN (Twisted Nematic), STN (Super TN), Ferroelectric (LCD), etc. are divided into TFT LCDs, etc., in which TFTs, which are switching elements of pixels, are incorporated for each pixel.

In addition, AMLCD and the like are used in which a driving device is manufactured for each pixel by dividing the screen into tens of thousands and hundreds of thousands, and the operation of the pixel is controlled using switching characteristics.

These LCDs have lower power consumption, easier light weight and shorter size than conventional cathode ray tubes, and can be used in color, large size, and high resolution, and are gradually expanding their range of use. Advantageous TFT-LCDs have attracted attention.

Hereinafter, a manufacturing method of a conventional thin film transistor liquid crystal display device will be described with reference to the accompanying drawings.

1A to 1D are cross-sectional views illustrating a method of manufacturing a thin film transistor liquid crystal display using a conventional five mask.

As shown in FIG. 1A, a gate metal film is deposited on an insulating substrate, that is, a glass substrate 11, and the gate metal film is patterned by an etching process using a first mask to form a gate electrode 12.

Subsequently, a gate insulating layer 13 is formed on the entire surface of the substrate 11 including the gate electrode 12.

As shown in FIG. 1B, undoped amorphous silicon (hereinafter, referred to as an a-Si layer) is deposited on the gate insulating layer 13, and the a-Si layer is selectively selected by an etching process using a second mask. Etching is performed to form the active layer 14.

As shown in FIG. 1C, a doped amorphous silicon layer (hereinafter referred to as an n ⁺ a-Si layer) and a source / drain electrode for forming a channel layer on the gate insulating layer 13 including the active layer 14. The metal film for forming the metal film is sequentially formed, and the source / drain electrode 16 and the channel layer 15 are formed by successively etching the metal film and the n ⁺ a-Si layer using a third mask.

As shown in FIG. 1D, the passivation layer 17 is formed on the entire surface of the substrate 11 including the source / drain electrodes 16, and any one of the source / drain electrodes 16 is formed using a fourth mask. A contact hole is formed to be exposed.

In addition, a pixel electrode 18 in contact with any one of the source / drain electrodes 16 is formed by depositing a transparent metal film, for example, an ITO metal film on the passivation layer 17 and selectively removing the ITO metal film using a fifth mask. ).

2A to 2E are cross-sectional views illustrating a method of manufacturing a thin film transistor liquid crystal display using four conventional masks.

As shown in FIG. 2A, a gate metal film is deposited on an insulating substrate such as a glass substrate 21, and the gate electrode 22 is formed on the glass substrate 21 by an etching process using a first mask. To form.

Subsequently, a gate insulating film 23 is formed on the entire surface of the substrate 21 including the gate electrode 22, and an active layer 24 of an amorphous silicon material, which is not doped, is doped with an amorphous silicon material. N ⁺ channel layer 25 and the metal layer 26 for the source / drain electrodes are deposited in this order.

The gray-tone photoresist 27 is deposited on the source / drain electrode metal layer 26 and subjected to an exposure and development process to pattern the gray-tone photoresist 27.

As shown in FIG. 2B, the metal layer 26 for source / drain electrodes is etched using the patterned gray-tone photoresist 27 as a second mask, and then the active layer 24 and the n ⁺ channel layer ( Etch 25).

As shown in FIG. 2C, an ashing process is performed on the patterned gray-tone photoresist 27 so that the source / drain electrode metal layer 26 is exposed.

As illustrated in FIG. 2D, the source / drain electrode metal layer 26 is etched using the ashed gray-tone photoresist 27 as a mask, and then the n ⁺ channel layer 25 is etched.

After removing the etched gray-tone photoresist 27 as shown in FIG. 2E, a protective film 28 is formed on the entire surface of the substrate 21 including the metal layer 26 for the source / drain electrodes. A contact hole is formed using a mask so that any one side of the source / drain electrode metal layer 26 is exposed.

The ITO material 29 is deposited on the passivation layer 28 including the contact hole, and the pixel electrode 29a is contacted with the source / drain electrode metal layer 26 through the contact hole using a fourth mask. Form.

However, the conventional method of manufacturing the thin film transistor liquid crystal display device has the following problems.

In the prior art, five photolithography processes must be performed with at least five masks to form a gate electrode, an active layer, a source / drain electrode, a pixel electrode, and a contact for connecting the source / drain electrode and the pixel electrode.

In this case, the mask designed to form the pattern is very expensive, and as the number of masks applied to the process increases, the cost of manufacturing the thin film transistor liquid crystal display increases proportionally.

In addition, since five photo etching processes are performed using five masks, the process is very complicated due to an increase in processing time due to frequent movement between equipment.

In order to solve this problem, a four-mask process using a gray-tone mask is used. However, the process number is never reduced compared to the five-mask process because a photoresist ashing process and a new process of etching the source / drain electrodes twice are added.

In addition, when the gray-tone mask is used, the source / drain electrodes on the channel side must be etched, so a total of two source / drain etching processes are required. There is a problem.

Accordingly, the present invention has been made to solve the above-mentioned problems of the prior art, a method of manufacturing a thin film transistor liquid crystal display device which can simplify the process and reduce the cost by performing four etching processes without adding a new process. The purpose is to provide.

According to an aspect of the present invention, there is provided a method of manufacturing a thin film transistor liquid crystal display device, including forming a gate electrode on a dielectric substrate using a first mask, and including a gate insulating film, an active layer, and a channel on the entire surface including the gate electrode. Depositing a layer and a source / drain electrode metal layer in sequence, etching the source / drain electrode metal layer and a channel layer using a second mask, depositing a protective layer on the resultant, and forming a third mask Selectively etching the passivation layer, the active layer, and the gate insulating layer by using a semiconductor layer, and forming a pixel electrode using a fourth mask so as to be connected to an upper portion of the passivation layer and the metal layer for the source / drain electrodes. It is preferable to characterize.

In addition, the etching process using the second mask is preferably characterized in that the etching up to a predetermined thickness inside the active layer.

And, during the etching process using the third mask, it is preferable to use any one of wet etching, dry etching.

Moreover, the source / drain electrode metal layer is preferably any one of Mo, MoW, Mo / Al / Mo, Mo / AlNd / Mo, Cr, Cr / AlNd, Cr / Al.

Hereinafter, a method of manufacturing a thin film transistor liquid crystal display device according to the present invention will be described in detail with reference to the accompanying drawings.

3A to 3D are cross-sectional views illustrating a method of manufacturing a thin film transistor liquid crystal display according to an exemplary embodiment of the present invention.

In the method of manufacturing a thin film transistor liquid crystal display device according to an exemplary embodiment of the present invention, as shown in FIG. 3A, a gate metal film is deposited on an insulating substrate, for example, a glass substrate 100, and the gate metal film is deposited on the gate metal film. The gate electrode 101 is formed on the glass substrate 100 by an etching process using a mask.

Subsequently, a gate insulating film 102 is formed on the entire surface of the substrate 100 including the gate electrode 101, and an undoped amorphous silicon layer (hereinafter referred to as an a-Si layer) is formed on the gate insulating film 102. (103), a doped amorphous silicon layer (hereinafter referred to as n ⁺ a-Si layer) 104, and a metal layer 105 for source / drain electrodes are sequentially deposited. In this case, the source / drain electrode metal layer 105 may use any one of Mo, MoW, Mo / Al / Mo, Mo / AlNd / Mo, Cr, Cr / AlNd, and Cr / Al.

Next, as shown in FIG. 3B, the source / drain electrode metal layer 105 and the n ⁺ a-Si layer 104 are successively etched using an etching process using a second mask in the source / drain electrode metal layer 105. Etching to form a source / drain electrode 105a and a channel layer 104a. In this case, the n ⁺ a-Si layer 104 is etched to form the channel layer 105a between the source and drain electrodes 105a, and is etched only up to a predetermined thickness inside the a-Si layer 103.

Subsequently, as shown in FIG. 3C, a protective layer 106 is deposited on the resultant layer, and a portion other than the channel layer 104a is protected to protect the channel layer 104a by an etching process using a third mask. The remaining a-Si layer 103 is etched to form an active layer 103a, and the gate insulating layer 102 and the protective layer 106 are simultaneously etched.

That is, when the a-Si layer 103 remains in a portion other than the channel layer 104a, the transmittance of the liquid crystal display is lowered, so the a-Si layer 103 remaining in the portion other than the channel layer 104a is reduced. Etch

In addition, dry or wet etching is used to etch the a-Si layer 103, the gate insulating layer 102, and the protective layer 106.

3D, a transparent metal film, for example, an ITO metal film is deposited on the passivation layer 106, and selectively etched the ITO metal film using a fourth mask to form a portion of the source / drain electrode 105a. The pixel electrode 107 in contact with either one is formed. In this case, since the source / drain electrode 105a may be damaged by the etching material during the ITO etching, the pixel electrode 107 is formed to cover the upper portion of the protective layer 106.

As described above, according to the manufacturing method of the thin film transistor liquid crystal display of the present invention, since the etching process is performed using four masks, the manufacturing cost can be reduced compared to the conventional method using five masks, thereby simplifying the process. Can be.

In addition, since the photoresist ashing process and the second etching process of the source / drain electrodes are unnecessary as compared to the four mask process using the gray-tone mask, the new process can be reduced.

In the case of a four mask process using a gray-tone mask, the source / drain electrodes are excessively over-etched due to a total of two source / drain etching processes, so that source / drain disconnection frequently occurs. The process can be performed only once to protect the source / drain electrode lines.

1A to 1D are cross-sectional views illustrating a method of manufacturing a thin film transistor liquid crystal display using a conventional five mask.

2A to 2E are cross-sectional views illustrating a method of manufacturing a thin film transistor liquid crystal display using four conventional masks.

3A through 3D are cross-sectional views illustrating a method of manufacturing a thin film transistor liquid crystal display according to an exemplary embodiment of the present invention.

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

100: glass substrate 101: gate electrode

102 gate insulating film 103 a-Si layer

103a: active layer 104: n ⁺ a-Si layer

104a: channel layer 105: metal layer for source / drain electrodes

105a: source / drain electrode 106: protective layer

107: pixel electrode

Claims (4)

Depositing a gate metal film on an insulating substrate, and then etching the gate metal film using a first mask to form a gate electrode; Depositing a gate insulating film, an undoped amorphous silicon layer, a doped amorphous silicon layer, and a metal layer for source / drain electrodes on the entire surface including the gate electrode; The source / drain electrode and the channel layer are etched by etching the source / drain electrode metal layer and the doped amorphous silicon layer using a second mask, and the undoped amorphous silicon layer is formed in the etching process using the second mask. Performing some etching; Depositing a protective layer over the resultant, and selectively etching the protective layer, the remaining undoped silicon layer, and the gate insulating film using a third mask to form an active layer; Depositing a pixel electrode metal film on the resultant protective layer, and etching the pixel electrode metal film using a fourth mask to form a pixel electrode contacted with any one of a source / drain electrode. A method of manufacturing a thin film transistor liquid crystal display device, characterized in that. delete The method of claim 1, A method of manufacturing a thin film transistor liquid crystal display device using any one of wet etching and dry etching during an etching process using the third mask. The method of claim 1, The source / drain electrode metal layer may be any one of Mo, MoW, Mo / Al / Mo, Mo / AlNd / Mo, Cr, Cr / AlNd, and Cr / Al.