KR20040059001A - Fabricating method of liquid crystal display device for simplifying process - Google Patents

Abstract

PURPOSE: A method for manufacturing an LCD(Liquid Crystal Display) having simplified processes is provided to form a spacer maintaining a cell gap simultaneously when forming a passivation layer, thereby capable of manufacturing the spacer without using a separate mask. CONSTITUTION: A liquid crystal is filled between a TFT(Thin Film Transistor) substrate and a color filter substrate(265) and then a liquid crystal layer(290) is formed. The TFT substrate and the color filter substrate(265) maintain a constant cell gap by a column spacer(430) and are formed at transparent substrates(200,260). The transparent substrates(200,260) are divided into a pixel region and a boundary region surrounding the pixel region. A TFT(310) is arranged at every pixel region of an upper portion of the transparent substrate(200) and applies a signal voltage to a pixel electrode(250). A passivation film(220) for protecting a source electrode(318) and a drain electrode(320) is formed at an upper portion of the TFT(310). The passivation film(220) is etched at an upper portion of the drain electrode(320), thereby forming a contact hole(330). Through the contact hole(330), the drain electrode(320) and the pixel electrode(250) are electrically connected. A black matrix(300) is formed on the color filter substrate(265) at every boundary region of the second transparent substrate(260). Color filter layers(280) of RGB(Red, Green, Blue) colors are formed at every pixel region.

Description

Manufacturing method of the liquid crystal display device which simplified the process {FABRICATING METHOD OF LIQUID CRYSTAL DISPLAY DEVICE FOR SIMPLIFYING PROCESS}

The present invention relates to a method for manufacturing a liquid crystal display device, and more particularly, to a method for manufacturing a liquid crystal display device including a TFT substrate having column spacers formed thereon.

The manufacturing process of the liquid crystal display device includes a series of processes in which a thin film transistor (TFT) substrate and a color filter substrate, which are completed through different manufacturing processes, are bonded together with a liquid crystal interposed therebetween.

In more detail, the manufacturing process of the liquid crystal display device starts with an alignment film coating and rubbing process for arranging liquid crystal molecules in a predetermined direction with respect to the TFT substrate and the color filter substrate, respectively. Usually, a short pattern is formed in a TFT substrate for sealing pattern printing for injecting liquid crystal and a short for connecting a common electrode terminal of the color filter substrate to a bonding pad of the TFT substrate. A spacer is formed in the cell to maintain a constant cell gap.

There are two types of spacers, ball and patterned. Ball-shaped spacers have a disadvantage in that the adhesion to the substrate and the dispersion density is not easy to control, and thus, patterned spacers are frequently used. The ball spacer is referred to as a ball spacer, and the patterned spacer is referred to as a column spacer. The column spacer is formed by a process of depositing, developing, and etching an organic polymer material. The column spacer has an advantage of having a wider contact area with the substrate, better distribution density control, and better adhesion with the substrate than the ball spacer. In particular, as the liquid crystal display device becomes larger, column spacers are mainly used.

1A to 1C are cross-sectional views showing a process for manufacturing a conventional column spacer.

In the color filter substrate, the black matrix 110 is formed on the transparent substrate 100 at the boundary of each pixel, and the color filter layer 120 is formed on each pixel. An overcoat layer 130 is formed on the color filter layer 120 for planarization. The photosensitive organic layer 140 is coated on the planarization layer 130 as shown in FIG. 1A.

Thereafter, as shown in FIG. 1B, the mask 150 is aligned on the color filter substrate 160 and irradiated with ultraviolet rays. When the photosensitive organic layer 140 irradiated with ultraviolet rays is developed, the column spacer 145 is formed as shown in FIG. 1C. Through the above manufacturing process, the color filter substrate used in the liquid crystal display according to the embodiment of the present invention is completed.

However, such a conventional color filter substrate manufacturing process uses a mask when forming the column spacer. The mask inputs layout data designed using a computer-aided design (CAD) to an electron beam lithography system and scans and forms an electron beam on a glass plate coated with a photoresist film according to the data. As such, a high cost is required to manufacture the mask. In addition, the use of exposure equipment and developing equipment required for the photolithography process is expensive, and the process has become complicated and the price of the liquid crystal display device has been increased.

In order to solve the above problems, an object of the present invention is to provide a method of manufacturing a liquid crystal display device having a column spacer without using a separate mask.

Other features and objects of the present invention will be described in detail in the configuration and claims of the invention below.

1A to 1C are cross-sectional views showing a manufacturing process of a conventional column spacer.

Figure 2 is a side cross-sectional view of a liquid crystal display device manufactured by an embodiment of the present invention.

3 is a cross-sectional view showing a manufacturing process for forming a TFT on a TFT substrate according to an embodiment of the present invention.

4A to 4D are procedure cross-sectional views showing a process of manufacturing a column spacer on a TFT substrate according to an embodiment of the present invention.

*** Explanation of symbols for main parts of drawing ***

100: transparent substrate 110, 300: black matrix

120, 280: color filter layers 130, 410: planarization film

140: photosensitive organic film 145, 430: column spacer

150: mask 200: first transparent substrate

205: TFT substrate 210: gate insulating film

220: protective film 250: pixel electrode

260: second transparent substrate 265: color filter substrate

290: liquid crystal layer 300: black matrix

310: thin film transistor 312: gate electrode

314: semiconductor layer 318: source electrode

320: drain electrode 330: contact hole

450: partial diffraction mask 452: first pattern

454: second pattern

According to an aspect of the present invention, there is provided a transparent substrate including a pixel area and a boundary area surrounding the pixel area; Forming a thin film transistor on an edge of the pixel region; Coating a photosensitive organic material on the transparent substrate on which the thin film transistor is formed; And patterning the photosensitive organic material to simultaneously form a passivation layer having a column spacer and a contact hole.

The forming of the thin film transistor may include forming a gate electrode on a transparent substrate; Forming a gate insulating layer on the transparent substrate and the gate electrode; Forming a channel layer on the gate insulating layer; And forming a source electrode and a drain electrode spaced apart from each other by a predetermined distance on the channel layer.

The photosensitive organic material is preferably coated with an acrylic resin by spin coating.

It is preferable to pattern the photosensitive organic material using a diffraction mask.

The method may further include forming a pixel electrode connected to the thin film transistor through the contact hole on the passivation layer.

It is preferable to form column spacers on the boundary region of the transparent substrate.

In addition, the present invention comprises the steps of forming a thin film transistor on a transparent substrate to achieve the above object; Coating a photosensitive organic material on the thin film transistor; Patterning the photosensitive organic material to simultaneously form a passivation layer having a column spacer and a contact hole; And forming a pixel electrode connected to the thin film transistor through the contact hole on the passivation layer, wherein the liquid crystal display device is simplified.

The forming of the passivation layer may include aligning a diffraction mask on the transparent substrate; Irradiating ultraviolet light to the photosensitive organic material through the diffraction mask; And developing the photosensitive organic material irradiated with ultraviolet rays.

According to the present invention, since the spacers for maintaining the cell gap of the liquid crystal display are simultaneously formed when forming the protective film of the TFT substrate, there is an effect of reducing the manufacturing cost of the liquid crystal display without using a separate mask.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a side cross-sectional view of a liquid crystal display device manufactured by an embodiment of the present invention.

As shown in the figure, the liquid crystal is filled between the TFT substrate 205 and the color filter substrate 265 to form the liquid crystal layer 290, and the TFT substrate 205 and the color filter substrate 265 are column spacers. By 430, a constant cell gap is maintained.

The TFT substrate 205 and the color filter substrate 265 are formed on the transparent substrates 200 and 260, and the transparent substrates 200 and 260 are divided into pixel regions and boundary regions surrounding the pixel regions. The pixel area means an area through which light of the backlight passes, and the boundary area is an area between each pixel area, and an area where light does not transmit due to the wiring of the TFT substrate 205 and the black matrix of the color filter substrate 265. it means.

In the TFT substrate 205, a TFT 310 is formed on each of the corners of each pixel region on the first transparent substrate 200 to apply and block a signal voltage to the pixel electrode 250. The TFT 310 is a gate electrode 312 to which a gate signal is applied, a semiconductor layer 314 that is activated in response to the gate signal to form a channel, and n ⁺ doped to form the channel 314. Ohmic contact layer (not shown) formed on both sides of the upper side), a gate insulating film 210 that electrically isolates the ohmic contact layer and the gate electrode 312, and formed on the ohmic contact layer to receive a data signal A source electrode 318 and a drain electrode 320 for applying a data signal input to the source electrode 318 to the pixel electrode 250 as the semiconductor layer 314 is activated. A passivation layer 220 is formed on the TFT 310 to protect the source electrode 318 and the drain electrode 320.

The passivation layer 220 on the TFT 310 protrudes up to the color filter substrate 265 to form a column spacer 430 that maintains a cell gap. The passivation layer 220 on the drain electrode 320 is etched to form a contact hole 330, and the drain electrode 320 and the pixel electrode 250 are electrically connected through the contact hole 330. do.

The black matrix 300 is formed at each boundary region of the second transparent substrate 260 in the color filter substrate 265, and the color filter layer 280 of red (R), green (G), and blue (B) is formed in each pixel region. ) Is formed. The planarization film 410 is formed on the color filter layer 280, and the transparent electrode 410 is formed on the color filter layer 280 as a common electrode. The transparent electrode 410 is formed of a transparent material such as indium tin oxide (ITO) and applies a voltage to the liquid crystal layer 290 together with the pixel electrode 250 of the TFT substrate 310. The transparent electrode 410, which is used as a common electrode, is deposited on the front surface of the color filter substrate 265 without distinction for each pixel to obtain a common voltage Vcom from the common voltage wiring of the TFT substrate 205 through silver dots. Licensed.

Hereinafter, the manufacturing process of the TFT substrate which comprises the above liquid crystal display device is demonstrated.

3 is a cross-sectional view showing a manufacturing process for forming a TFT on a TFT substrate according to an embodiment of the present invention.

First, as illustrated in FIG. 3A, an electrode material is deposited on the transparent substrate 200, and then the gate electrode 312 is formed on the transparent substrate 200 by a photolithography process using a first mask (not shown). Form. The photolithography process consists of a series of continuous processes such as photoresist coating, alignment and exposure, development, and cleaning. In the production of liquid crystal display device panels where productivity is important, such processes are continuously performed in automated facilities. The exposure process is performed by placing the mask in position, aligning the alignment keys of the mask and the substrate, and irradiating a light source, which requires high precision in aligning the mask and the substrate.

As shown in FIG. 3B, the gate insulating layer 210, the semiconductor layer 314, and the metal layer 315 of SiN _x material are sequentially formed on the resultant. In this case, the semiconductor layer 314 stacks amorphous silicon and a high concentration of N-doping amorphous silicon.

3C, a photoresist film is formed on the metal layer 315, and then a pattern of the photoresist film remaining on the semiconductor layer 314 is formed by using a second mask (not shown), which is a diffraction mask. However, by applying diffraction exposure to the photoresist on the metal layer 315 on the gate electrode 312 so as to have a thin thickness compared to the photoresist pattern of the other region, the laminated film of the region exposed through the pattern of the photoresist 400 Etch until the gate insulating layer 210 is exposed.

3D, the diffraction exposure is applied to selectively remove the upper photoresist 400 of the metal layer 315 having a thickness thinner than that of the photoresist pattern of another region.

As shown in FIG. 3E, the photoresist pattern is selectively removed to etch the exposed metal layer 315, and then the semiconductor layer 314 is etched by a predetermined thickness to be formed on both sides of the semiconductor layer 314. After forming the spaced source / drain electrodes 318 and 320 and removing the remaining photoresist pattern, the TFT including the gate electrode 312, the semiconductor layer 314, the source electrode 318, and the drain electrode 320 may be formed. Is manufactured on the glass substrate 200.

Although FIG. 3 has described the process of manufacturing a TFT using two masks including a diffraction mask, it is also possible to manufacture a TFT using three masks. The method of manufacturing a liquid crystal display device in which photolithography is applied by applying two masks can reduce manufacturing cost and simplify the process compared to applying three masks. In other words, the photoresist is applied at every step and a photo process is performed using a mask. However, the reduction of the step may contribute to reduction of manufacturing cost and process simplification.

4A to 4D are procedure cross-sectional views showing a process of manufacturing a column spacer on a TFT substrate according to an embodiment of the present invention.

First, as shown in FIG. 4A, the photosensitive organic layer 440 is uniformly coated on the entire upper surface of the transparent substrate 200 including the TFT 310 by a desired cell gap thickness. Photo acryl, which is an acrylic resin, may be used as the photosensitive organic layer 440.

It is preferable to apply the photosensitive organic layer 440 using spin coating. Spin coating is a process of dropping a photoresist on a rotating substrate to apply the organic layer by centrifugal force of the substrate. Such spin coating has an advantage of simple and rapid application of an organic film.

After the photosensitive organic layer is formed, the diffraction mask 450 having the pattern of the column spacer and the contact hole is formed on the transparent substrate 200 to which the photosensitive organic layer 440 is applied, as shown in FIG. 4B. At this time, since the shrinkage and expansion of the substrate due to the temperature change causes misalignment, maintaining a constant temperature is very important.

Next, ultraviolet rays are irradiated to the photosensitive organic film 440 through a pattern formed in the partial diffraction mask 450. The photosensitive organic film has a positive type in which a region irradiated with ultraviolet light reacts with a developer and is dissolved, and a negative type in which a region irradiated with ultraviolet light does not react with a developer. In FIG. 4B, a photosensitive organic film of negative type ( 440 is shown.

The diffraction mask 450 used in the embodiment of the present invention includes a first pattern 452 and a second pattern 454. In the drawings, parts indicated by hatched parts represent opaque parts and other parts indicate transparent parts. Ultraviolet rays are irradiated through the transparent part. When using a positive type photosensitive organic film, the transparent and opaque portions of the mask are alternately formed.

The first pattern 452 is for forming column spacers, and the second pattern 314 is for forming a protective film. The second pattern 454 is formed in a slit shape as shown in the figure. Ultraviolet light passes through the first pattern 452 as it is, but partially passes through the second pattern 454 to be irradiated to the photosensitive organic film 440. The thickness of the passivation layer may be determined by adjusting the amount of ultraviolet light radiated through the second pattern 314 at intervals between the slits.

When the ultraviolet ray is irradiated to the transparent substrate 200 coated with the photosensitive organic layer 440 using the mask 450 as described above, and then reacted with a developer, the column spacer 430 and the protective layer 220 as shown in FIG. 4C are formed. . As described above, the height of the passivation layer 220 may be adjusted by the slit interval of the second pattern 454 formed on the mask 310, and the height of the column spacer 430 may be adjusted by the thickness of the photosensitive organic layer to be applied.

Although the case where the column spacer 430 is formed on the TFT 310 is illustrated in the drawing, the position of the column spacer 430 is not limited thereto and may be formed in the boundary region of the transparent substrate 200. The boundary region corresponds to the region where the black matrix of the color filter substrate is formed so that the aperture ratio does not decrease due to the column spacer 430.

The contact hole 330 formed at the same time as the column spacer 430 is formed on the drain electrode 320 to expose the drain electrode 320.

Thereafter, as illustrated in FIG. 4D, the transparent electrode material is formed on the resultant material, and then patterned to form the pixel electrode 250 in the pixel region. The pixel electrode 250 is electrically connected to the drain electrode 320 of the TFT through the contact hole.

When the TFT substrate is manufactured by the above process, the number of masks used in the overall manufacturing process of the liquid crystal display can be reduced because the column spacer is formed at the same time as the protective film is formed. That is, the column spacer can be formed without using a mask that is conventionally used when manufacturing the column spacer on the color filter substrate.

Many details are set forth in the foregoing description, but they should be construed as preferred embodiments rather than limiting the scope of the invention.

Therefore, the scope of the invention should not be defined by the described embodiments, but should be defined by the claims and the equivalents of the claims.

According to the present invention, since the spacers maintaining the cell gap of the liquid crystal display are simultaneously formed when forming the protective film of the TFT substrate, there is an advantage that the spacers can be manufactured without using a separate mask.

There is an effect that can reduce the manufacturing cost by simplifying the process than when manufacturing a spacer on a color filter substrate using a mask in the prior art.

Claims (10)

Preparing a transparent substrate including a pixel region and a boundary region surrounding the pixel region; Forming a thin film transistor on an edge of the pixel region; Coating a photosensitive organic material on the transparent substrate on which the thin film transistor is formed; And And patterning the photosensitive organic material to simultaneously form a passivation film having a column spacer and a contact hole. The method of claim 1, wherein the forming of the thin film transistor comprises: Forming a gate electrode on the transparent substrate; Forming a gate insulating layer on the transparent substrate and the gate electrode; Forming a channel layer on the gate insulating layer; And And forming a source electrode and a drain electrode spaced apart from each other by a predetermined distance on the channel layer. The method of claim 1, wherein the photosensitive organic material is coated by spin coating. The method of claim 1, wherein the photosensitive organic material is an acrylic resin. The method of claim 1, wherein the photosensitive organic material is patterned using a diffraction mask. The method of claim 1, further comprising forming a pixel electrode connected to the thin film transistor through the contact hole on the passivation layer. The method of claim 1, wherein a column spacer is formed on the boundary region of the transparent substrate. Forming a thin film transistor on the transparent substrate; Coating a photosensitive organic material on the thin film transistor; And Patterning the photosensitive organic material to simultaneously form a protective film having a column spacer and a contact hole; And And forming a pixel electrode connected to the thin film transistor through the contact hole on the passivation layer. The method of claim 8, wherein the forming of the protective film, Aligning the diffraction mask on the transparent substrate; Irradiating ultraviolet light to the photosensitive organic material through the diffraction mask; And The manufacturing method of the liquid crystal display device which simplified the process characterized by including developing the photosensitive organic substance irradiated with the ultraviolet-ray. The method of claim 8, wherein the photosensitive organic material is coated by spin coating.