KR20020085236A - Method for manufacturing of active matrix liquid crystal display - Google Patents

Abstract

PURPOSE: A method for fabricating an active matrix type liquid crystal display device is provided to carry out the etching by using four masks in the same equipment for reducing the fabricating steps and cost. CONSTITUTION: A method for fabricating an active matrix type liquid crystal display device includes the steps of forming gate electrodes on an insulating substrate by using a first mask, depositing a gate insulating film, an active layer, and a source/drain metal layer on the entire surface of the substrate including the gate electrodes, alternatively forming a second mask on the source/drain metal layer, etching the active layer and the source/drain metal layer in sequence by using the second mask and etching the second mask to alternatively expose the source/drain metal layer surface, etching the source/drain metal layer by using the etched second mask to expose the gate insulating film, forming a protecting film(28) having contact holes by using a third mask to expose to ether source/drain metal layer, and forming pixel electrodes(29a) by using a fourth mask to be connected to the source/drain metal layer via the contact holes.

Description

Manufacturing method of an active matrix liquid crystal display device {METHOD FOR MANUFACTURING OF ACTIVE MATRIX LIQUID CRYSTAL DISPLAY}

The present invention relates to a method for manufacturing an active matrix liquid crystal display (AMLCD), and more particularly to a method for manufacturing an active matrix liquid crystal display device for reducing the process steps.

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 liquid crystal display device will be described with reference to the accompanying drawings.

1A to 1D are cross-sectional views illustrating a conventional method for manufacturing a liquid crystal display device.

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. ).

However, the above-described conventional manufacturing method of the liquid crystal display device has the following problems.

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 liquid crystal display device increases in proportion thereto.

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.

The present invention has been made in order to solve the above problems, the active matrix type liquid crystal display that can simplify the process and reduce the cost because the etching process is performed four times using a gray-tone mask (Gray-Tone Mask) Its purpose is to provide a method for manufacturing a device.

1A to 1D are cross-sectional views illustrating a method of manufacturing a conventional liquid crystal display device.

2A through 2E are cross-sectional views illustrating a method of manufacturing an active matrix liquid crystal display device according to an exemplary embodiment of the present invention.

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

21 glass substrate 22 gate electrode

23 gate insulating film 24 active layer

25 channel layer 26 source / drain electrodes

27: gray-tone photoresist 28: protective film

29a: pixel electrode

A method of manufacturing an active matrix liquid crystal display device of the present invention for achieving the above object comprises the steps of forming a gate electrode on the insulating substrate using a first mask, a gate insulating film, an active layer on the entire surface including the gate electrode Depositing a metal layer for source / drain electrodes in order, selectively forming a gray-tone mask on the metal layer, and then using the gray-tone mask, an active layer and a metal layer for source / drain electrodes in the same equipment. Etching, etching the gray-tone mask so that the surface of the source / drain electrode metal layer is selectively exposed, and using the ashed gray-tone mask, the source / drain electrode metal layer to expose the gate insulating layer. Etching, and either side of the source / drain electrode metal layer is exposed. Forming a protective film having a contact hole, and the rock, characterized by a yirueojim including the step of forming a pixel electrode so that through the contact hole connecting the metal layer for the source / drain electrodes.

In the method of manufacturing an active matrix liquid crystal display device of the present invention, the active layer and the metal layer for source / drain electrodes are etched using a dry etching process, and the etching gas SF ₆ + O ₂ + He or SF ₆ + HCl + O ₂ is used. It is preferable.

In addition, the active layer, the metal layer etching for source / drain electrodes is preferably made of PE (Plasma Etching) type equipment.

In addition, the gray-tone mask ashing is preferably proceeded to the RIE (Reactive Ion Etching) type of equipment.

In addition, the gray-tone mask ashing gas is preferably O ₂ , CF ₄ , CHF ₆ .

In addition, the metal layer etching for the source / drain electrodes may be wet etching and dry etching to expose the gate insulating layer.

The source / drain electrode metal layer is preferably MO, Al, MoTa, α-Ta, Ti, ITO, and has a thickness of 1000 to 3000 Pa.

In addition, when the RIE equipment is used, the active layer and the metal layer etching gas SF ₆ + O ₂ + He and SF ₆ + HCl + O ₂ for the source / drain electrodes are used, the RF power is 300 or more, the electrode gap is 500 mm, and the pressure is 50 mTorr. Above, it is preferable that the gray-tone mask ashing controls O ₂ gas, other temperature and power without using SF ₆ .

Hereinafter, a method of manufacturing an active matrix liquid crystal display device of the present invention will be described in detail with reference to the accompanying drawings.

2A through 2E are cross-sectional views illustrating a method of manufacturing an active matrix liquid crystal display device according to an exemplary embodiment of the present invention.

As shown in FIG. 2A, a gate metal film is deposited on an insulating substrate, for example, a glass substrate 21, and the gate electrode 22 is formed on the glass substrate by an etching process using a first mask. 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. At this time, the source / drain electrode metal layer 26 uses a single or alloy such as Mo, Al, MoW, MoTa, α-Ta, Ti, ITO, and the like and has a thickness of 1000 to 3000 GPa or more.

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 active layer 24 and the n ⁺ channel layer 25 and the metal layer for source / drain electrodes are subjected to a dry etching process using the patterned gray-tone photoresist 27 as a second mask. Etch (26) sequentially.

As shown in FIG. 2C, a dry ashing process is performed on the patterned gray-tone photoresist 27 so that the source / drain electrode metal layer 26 is exposed. At this time, the ashing gas is used O ₂ , CF ₄ , SH ₆ , CHF ₆ .

In this case, when the etching process and the ashing process are continuously performed in the same equipment as the RIE type equipment, the etching gas of the active layer 24, the n ⁺ channel layer 25 and the metal layer 26 for the source / drain electrodes is SF. ₆ + O ₂ + He or SF ₆ + HCl + O ₂ is used, and the RF power is 300 or more and the inter-electrode gap is 50 mm or more.

On the other hand, when the etching process is a PE type equipment, the active layer 24, the n ⁺ channel layer 25 and the source / drain electrode metal layer 26 proceeds continuously, the gray-tone photoresist 27 Ashing of the proceeds to the RIE type equipment.

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. In this case, the source / drain electrode metal layer 26 may be etched using wet etching or dry etching.

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.

As described above, according to the method of manufacturing the active matrix liquid crystal display device of the present invention, since the etching process is performed using four masks, the manufacturing cost is reduced and the process can be simplified as compared with the conventional method.

In addition, the process is continuously carried out in the same equipment, the process is very simplified, stabilized and can reduce the process time.

The single data wiring is etched using a dry etching process, thereby minimizing data open by avoiding excessive CD bias.

Claims (8)

Forming a gate electrode on the insulating substrate using a first mask; Sequentially depositing a gate insulating film, an active layer, and a metal layer for source / drain electrodes on the entire surface including the gate electrode; Selectively forming a second mask on the metal layer for the source / drain electrodes; Etching the active layer and the source / drain electrode metal layer sequentially in the same device using the second mask, and ashing the second mask to selectively expose the surface of the source / drain electrode metal layer; Etching the metal layer for the source / drain electrodes using the ashed second mask to expose a gate insulating layer; Forming a protective film having a contact hole by using a third mask to expose either side of the source / drain electrode metal layer; And forming a pixel electrode using a fourth mask to be connected to the source / drain electrode metal layer through the contact hole. The method of claim 1, And the second mask is a gray-tone photoresist. The method of claim 1, The active layer and the metal layer for source / drain electrodes are etched using a dry etching process, and the etching gas is SF ₆ + O ₂ + He or SF ₆ + HCl + O ₂ , and the RF power is 300 Watt or more and the gap between electrodes A manufacturing method of an active matrix liquid crystal display device, characterized in that 50mm. The method of claim 1, The active layer and the metal layer etching for the source / drain electrode is a method of manufacturing an active matrix liquid crystal display device, characterized in that the PE (Plasma Etching) type of equipment. The method of claim 1, The method of manufacturing an active matrix liquid crystal display device, characterized in that the process proceeds to the reactive ion etching (RIE) type of equipment during the second mask ashing. The method according to any one of claims 1 to 5, A method of manufacturing an active matrix liquid crystal display device using O ₂ , CF ₄ or CHF ₆ as the second mask ashing gas. The method of claim 1, A method of manufacturing an active matrix liquid crystal display device using wet and dry etching processes to etch the metal layer for source / drain electrodes to expose the gate insulating layer. The method of claim 1, MO, Al, MoTa, α-Ta, Ti, ITO is used as the source / drain electrode metal layer, and the thickness of the source / drain electrode metal layer is 1000 to 3000 GPa. Manufacturing method.