KR100493866B1 - A method for fabricating a spacer for LCD - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a spacer forming method having a function of maintaining a gap of a liquid crystal panel.

The spacer forming method according to the present invention is to form a spacer having a desired height and shape by filling a spacer material in a partially developed portion of the PR layer by an inkjet method during a photo process of forming a color filter substrate or a thin film transistor array substrate. .

In this way, a patterned spacer having a desired shape can be formed without a separate process for forming the spacer, thereby simplifying the process and saving material costs, thereby improving the competitiveness of the product.

Description

A method for fabricating a spacer for LCD

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly to a method of forming a patterned spacer formed in an array substrate or color filter for a liquid crystal display device.

Hereinafter, the structure and operation characteristics thereof according to the liquid crystal panel will be described with reference to FIG. 1.

1 is a view schematically showing a general liquid crystal panel.

As shown, the liquid crystal panel 11 includes a color filter 7 including a black matrix 6 and a sub-color filter (red, green, blue) 8, and a common electrode transparent on the color filter 7. And an upper substrate 5 having an 18 formed thereon, and a lower substrate 22 having an array wiring including a pixel region P and a pixel electrode 17 formed on the pixel region and a switching element T. The liquid crystal 14 is filled between the upper substrate 5 and the lower substrate 22.

The lower substrate 22 is also referred to as an array substrate, and the thin film transistor T, which is a switching element, is positioned in a matrix type, and the gate wiring 13 and the data wiring 15 passing through the plurality of thin film transistors cross each other. Is formed.

The pixel area P is an area defined by the gate line 13 and the data line 15 intersecting each other. The pixel electrode 17 formed on the pixel region P uses a transparent conductive metal having relatively high light transmittance, such as indium-tin-oxide (ITO).

Hereinafter, a manufacturing procedure of the liquid crystal panel will be briefly described with reference to flowchart 2.

FIG. 2 is a flowchart illustrating a manufacturing process of a liquid crystal panel generally applied. In the st1 step, a lower substrate is first prepared. A plurality of thin film transistors (TFTs) are arranged on the lower substrate as switching elements, and pixel electrodes are formed in one-to-one correspondence with the TFTs.

The st2 step is to form an alignment layer on the lower substrate.

The alignment layer formation includes a coating and rubbing process of the polymer thin film. The polymer thin film is generally referred to as an alignment layer, and must be deposited with a uniform thickness over the entire lower substrate, and rubbing should be uniform.

The rubbing is a main process of determining the initial alignment direction of the liquid crystal. The rubbing of the alignment layer enables the normal liquid crystal to be driven and has a uniform display characteristic.

In general, a polyimide series, which is an organic organic alignment layer, is mainly used for the alignment layer.

The rubbing process refers to rubbing the alignment layer in a predetermined direction using a cloth, and the liquid crystal molecules are aligned according to the rubbing direction.

The st3 step represents a process of printing a seal pattern.

The seal pattern in the liquid crystal cell has two functions of forming a gap for injecting the liquid crystal and preventing leaking of the injected liquid crystal. The seal pattern is a step of uniformly forming a thermosetting resin in a desired pattern, and screen printing has become mainstream.

st4 step is to remove spacer It shows the process of spreading.

In the manufacturing process of the liquid crystal cell, a spacer having a constant size is used to maintain a precise and uniform gap between the upper substrate and the lower substrate. Therefore, the spacer should be dispersed at a uniform density with respect to the lower substrate, and the dispersion method can be broadly divided into a wet dispersion method in which a spacer is mixed by spraying alcohol and the like and a dry dispersion method in which only the spacer is dispersed.

In addition, dry dispersion is divided into electrostatic spraying using static electricity and antistatic spraying using gas pressure. In the liquid crystal cell having a structure susceptible to static electricity, the electrostatic spraying method is frequently used.

After the spacer spreading process is completed, the process proceeds to the bonding process of the upper substrate as the color filter substrate and the lower substrate as the thin film transistor array substrate (st5).

The joining arrangement of the upper substrate and the lower substrate is determined by the margin given in the design of each substrate, and usually a precision of several μm is required. If the two substrates are out of the bonding error range, light leaks out, so that the desired image quality characteristics cannot be expected when the liquid crystal cell is driven.

The st6 step is a step of cutting the liquid crystal cell prepared in the st1 to st5 step into a unit cell. In general, a liquid crystal cell undergoes a process of forming a plurality of liquid crystal cells on a large area glass substrate and then separating them into a single liquid crystal cell, which is a cell cutting process.

In the initial manufacturing process of the liquid crystal display device, a process of cutting several cells at the same time and then cutting them into cell units is performed. However, as cell sizes increase, the cells are cut into unit cells and then a liquid crystal is injected.

The cell cutting process is composed of a diamond pen having a hardness higher than that of a glass substrate, and a scribe process for forming a cutting line on the surface of the substrate and a break process for applying force.

The st7 step is a step of injecting liquid crystal into the liquid crystal cell cut into each unit cell.

The unit liquid crystal cell has a gap of several μm in an area of several hundred cm ² . Therefore, the vacuum injection method using the pressure difference between the inside and outside of the cell is most widely used as a method of effectively injecting the liquid crystal into the cell of such a structure.

In the above-described process, the spacer mainly uses a separate standardized spacer as described, but this method has many limitations in the method of dispersing the spacer.

Therefore, many methods of patterning and forming spacers during the manufacturing process of the substrate have been studied.

The spacer directly patterned on the substrate may be formed on the lower substrate or the upper substrate (color filter substrate). When the spacer is formed on the lower substrate, the spacer is generally formed on the array wiring of the lower substrate.

Hereinafter, a conventional patterned spacer forming method will be described with reference to the processes of FIGS. 3A to 3F.

First, as shown in FIG. 3A, a conductive metal is deposited on a transparent insulating substrate 22 and patterned by a first mask process to form a gate wiring (13 in FIG. 1) and a gate electrode 24.

Next, a gate insulating film 26 serving as a first insulating film is formed on the entire surface of the substrate 22 on which the gate electrode 24 and the gate wiring (13 in FIG. 1) are formed.

Next, as shown in FIG. 3B, a pure amorphous silicon layer (a-Si: H) and an impurity amorphous silicon layer (n + or p + a-Si) are formed on the gate insulating layer 26 on the gate electrode 24. : H) is deposited and patterned by a second mask process to form an active layer 30 and an ohmic contact layer 32.

A conductive metal is deposited on the entire surface of the substrate 22 on which the ohmic contact layer 30 and the active layer 32 are patterned, and is patterned by a third mask process to overlap the ohmic contact layer 30 in plan view. And a source electrode 34 extending in one direction from the data line 15 and a drain electrode 36 spaced apart from the predetermined distance.

After forming the data line 15 and the source and drain electrodes 34 and 36, the ohmic contact layer 32 exposed between the source electrode 34 and the drain electrode 36 is successively removed to form an active layer ( Expose a portion of 30) (ie, active channel).

Next, as shown in FIG. 3C, an organic compound including benzocyclobutene (BCB) and an acrylic resin (resin) on the entire surface of the substrate 22 on which the source and drain electrodes 34 and 36 are formed. One selected from the group of insulating materials is coated to form a first passivation layer 38.

Subsequently, the passivation layer 38 is patterned by a fourth mask process to form a contact hole 40 exposing a part of the drain electrode 116.

As shown in FIG. 3D, the transparent conductive metal is deposited on the first passivation layer 38 and patterned by a fifth mask process to form the pixel electrode 17, which is a transparent electrode contacting the drain electrode 36. Form.

Subsequently, a second passivation layer 42 is formed on the pixel electrode 17.

Through the process as described above, the thin film transistor array substrate may be formed.

 3E to 3F illustrate a process for forming a spacer on the thin film transistor array substrate.

As shown in FIG. 3E, the photosensitive resin is apply | coated to the whole surface of the board | substrate 22 in which the said 2nd protective film 42 was formed, and the photosensitive resin layer 43 is formed. (For example, a positive type is demonstrated.).

Subsequently, the mask M composed of the transmissive portion E and the blocking portion F is positioned on the resin layer 43, and then irradiated with light L from the upper portion of the mask M to form a lower resin layer ( 6 mask process of exposing 43) is performed.

When the exposed resin layer 43 is developed, as shown in FIG. 3F, a patterned spacer 46 may be formed at a desired position.

However, the conventional method for forming a spacer uses a method of coating a material forming the spacer on the entire surface of the substrate and then developing it.

At this time, 90% of the spacer forming material coated on the substrate is removed during the developing process. As a result, the remaining 90% of the spacer forming material is wasted in order to form as much as 10% of the spacer forming material in a predetermined pattern, resulting in an increase in material cost.

In addition, the process is added to cause a decrease in yield.

The present invention has been proposed for the purpose of solving the above-mentioned problems, and proposes a method of forming a spacer by using an inkjet method during a process of forming a thin film transistor substrate, particularly a photo process of forming a pixel electrode.

In this way, the process can be simplified and the loss of material costs can be reduced.

In the spacer forming method according to the present invention for achieving the object as described above in the spacer forming method for a liquid crystal display device formed on the first substrate or the second substrate to maintain a gap between the first substrate and the second substrate, Forming a PR layer on the front surface of the substrate; Placing a mask composed of a transmissive portion and a blocking portion on an upper portion of the PR layer, and then exposing light to an upper portion of the mask to expose a lower PR layer; Developing the PR layer to remove a portion corresponding to the transmission part; Filling the spacer material by removing the PR layer with an inkjet method and curing the spacer material; Removing the PR layer to expose the cured spacers.

An array substrate for a liquid crystal display device according to an aspect of the present invention comprises: a gate wiring and a data wiring crossing a mutually defined pixel region on a substrate; A switching element configured at the intersection of the gate wiring and the data wiring; A transparent pixel electrode connected to the switching element and extending through the pixel region and above the gate line; And a patterned spacer formed on the transparent pixel electrode overlying the gate line.

The pixel electrode may be formed to extend over a portion of the data line, and in this case, a patterned spacer may be further formed on the pixel electrode extending over the data line.

According to an aspect of the present invention, there is provided a method of manufacturing an array substrate for a liquid crystal display device, the method including: forming a gate electrode and a gate wiring on a substrate; Forming a gate insulating film on an entire surface of the substrate on which the gate wiring and the gate electrode are formed; A second mask process step of forming an active layer and an ohmic contact layer on the gate insulating layer on the gate electrode; A third mask process step of forming a source electrode in contact with the ohmic contact layer, a drain electrode spaced apart from the predetermined distance, and a data line connected to the source electrode; Forming a passivation layer on the entire surface of the substrate on which the source and drain electrodes are formed, and exposing a portion of the drain electrode; Forming a transparent metal layer on an entire surface of the substrate on which the protective film is formed; Applying a photoresist layer on the transparent metal layer; Placing a mask including a transmissive part and a blocking part on an upper portion of the substrate on which the photoresist layer is applied, and exposing light to the upper part of the mask to expose a lower photoresist layer; Developing the exposed photoresist layer to remove a portion corresponding to the transmission portion; Filling the spacer material in the transmissive portion corresponding to the gate wiring with an inkjet method and curing the spacer material; Removing the transparent electrode exposed between the remaining PR layers; A fifth mask process of removing the remaining PR layer to form a pixel electrode in contact with the drain electrode and extending through the pixel region to an upper portion of the gate wiring, and a patterned spacer on the pixel electrode extending to the gate wiring; Steps.

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

Example

The present invention is characterized in that a spacer is formed by an inkjet method during a photo process of forming a thin film transistor array substrate.

4 is a view schematically showing one pixel of an array substrate for a liquid crystal display according to the present invention.

As shown, the gate wiring 101 is formed on the substrate 100 in one direction, and the data wiring 110 defining the pixel region P is formed by crossing the gate wiring 101 vertically.

The thin film transistor T including the gate electrode 102, the active layer 106, the source electrode 112, and the drain electrode 114 is formed at the intersection of the two wirings 101 and 110.

The transparent pixel electrode 124 is formed in the pixel region P while being in contact with the drain electrode 114.

The pixel electrode 124 overlaps the gate wiring 101, and in the case of a liquid crystal display device having a high aperture ratio, the pixel electrode 124 extends above the data wiring 110.

In the above-described configuration, a patterned spacer 126 is formed on the gate wiring 101 and the data wiring 110, and the pixel electrode extending above the data wiring 110 and the gate wiring 101 is formed. 124) is formed on top.

In the above-described configuration, the patterned spacer 126 is formed during the photo process of forming the pixel electrode 124 using an inkjet method.

In this case, since a separate photo mask process for forming the spacer can be omitted, the process can be simplified, and the material cost can be reduced by using the inkjet method.

Hereinafter, a method of manufacturing an array substrate for a liquid crystal display device according to the present invention including the patterned spacer will be described with reference to FIGS. 5A to 5H.

5A to 5H are cross-sectional views illustrating a manufacturing process of an array substrate for a liquid crystal display device according to a process sequence of the present invention.

First, as shown in FIG. 5A, the conductive metal is deposited on the transparent insulating substrate 100 and patterned by a first mask process to form the gate wiring 101 and the gate electrode 102 connected thereto.

Next, a gate insulating film 104 as a first insulating film is formed on the entire surface of the substrate 100 on which the gate electrode 102 and the gate wiring 101 are formed.

In this case, the gate electrode 102 is formed of one selected from a conductive metal material including aluminum (Al), aluminum alloy, tungsten (W), molybdenum (Mo), chromium (Cr), and the gate insulating film 104 It is formed as one selected from the group of inorganic insulating materials including silicon nitride (SiN _X ) and silicon oxide (SiO ₂ ).

Next, as shown in FIG. 5B, pure amorphous silicon (a-Si: H) and impurity amorphous silicon (n + or p + a-Si: H) are formed on the gate insulating film 104 on the gate electrode 102. ) Is sequentially deposited and patterned by a second mask process to form an active layer 106 and an ohmic contact layer 108.

Next, as shown in FIG. 5C, a conductive metal is deposited on the entire surface of the substrate 100 on which the active layer 106 is patterned and patterned by a third mask process to planarly overlap the ohmic contact layer 108. The data line 110, the source electrode 112 extending in one direction from the data line 110, and the drain electrode 114 spaced apart from the predetermined distance are formed.

The data line 110, the source electrode 112, and the drain electrode 114 are formed of one selected from the group of conductive metals described above.

After forming the data line 110 and the source and drain electrodes 112 and 114, a portion of the active layer 106 is removed by successively removing the ohmic contact layer 108 exposed between the two electrodes 112 and 114. (I.e., active channel) is exposed.

Next, as shown in FIG. 5D, an organic insulating material including benzocyclobutene (BCB) and an acrylic resin (resin) on the entire surface of the substrate 100 on which the source and drain electrodes 112 and 114 are formed. One selected from the group is coated to form a first passivation layer 116.

Subsequently, the passivation layer 116 is patterned by a fourth mask process to form a contact hole 118 exposing a part of the drain electrode 116.

Next, as shown in FIG. 5E, one of the transparent conductive metal groups including indium tin oxide (ITO) and indium zinc oxide (IZO) is formed on the entire surface of the substrate on which the passivation layer 116 is formed. Deposition to form a transparent metal layer 120.

Subsequently, a photoresist layer (hereinafter referred to as "PR") 122 is formed on the entire surface of the substrate 100 on which the transparent metal layer 120 is formed. The mask M including the transmission part E and the blocking part F is positioned on the PR layer 122.

The blocking portion F corresponds to the portion H where the pixel electrode is formed, and the transmissive portion E corresponds to the other region.

In this case, the transmissive portion E may correspond to the spacer forming portion I, which is a part of the portion H where the pixel electrode is formed, overlaps the gate wiring 101 and the data wiring 110.

Subsequently, a process of irradiating the upper portion of the mask M with light and exposing the lower PR layer and then developing the same is shown in FIG. 5F.

As shown in FIG. 5F, in the PR layer in which the exposure process and the development process are performed, the remaining PR layers except for the pixel electrode forming unit H are removed. At this time, the PR layer corresponding to some of the spacer forming portions I of the pixel electrode 17 forming portions is also removed.

 Subsequently, a process of filling and curing the spacer material is performed using an inkjet method in which the spacer material 300 is dropped through the nozzle 200 only in the spacer forming portion I from which the PR layer is removed.

The spacer material may be an insulating resin that withstands the etching solution and the strip solution, which are used in the patterning process of the metal layer and the process of removing the PR layer.

Next, a process of etching the exposed metal layer between the remaining PR layer 122 ′ is performed so that a transparent metal layer remains only under the PR layer, as shown in FIG. 5G.

Of course, the metal layer is still present under the spacer 126.

 Subsequently, the process of removing the PR layer is performed, and the result as shown in FIG. 5H can be obtained.

That is, as shown in FIG. 5H, a pixel electrode 124 in contact with the drain electrode 114 is formed in the pixel region, and the pixel electrode 124 overlaps the gate wiring 101 to form a storage capacitor C _ST. ).

Through the above process, an array substrate for a liquid crystal display device including a patterned spacer according to the present invention can be manufactured.

Unlike the conventional process, the process as described above is manufactured through the 5 mask process to the patterned spacer, and thus, the process is simplified. In addition, since the spacer can be formed only in the desired region by using the inkjet method, there is an advantage that the material cost can be reduced.

In the present invention, a thin film transistor array substrate has been described as an example. However, such a process method can be applied even during a process of manufacturing a color filter substrate.

Therefore, the method of manufacturing a thin film transistor array substrate according to the present invention is a method capable of manufacturing up to a spacer in a 5 mask process, thereby simplifying the process compared to the conventional method, thereby improving yield by shortening the process time.

In addition, since the spacer can be formed only in a desired area by using the inkjet method, waste of material can be prevented and cost can be reduced.

1 is a view schematically showing a liquid crystal panel,

2 is a flowchart illustrating a procedure of manufacturing a liquid crystal panel;

3A to 3F are cross-sectional views illustrating a process of forming an array substrate for a liquid crystal display device including a spacer, according to a conventional process procedure

4 is an enlarged plan view schematically showing one pixel of an array substrate for a liquid crystal display device according to the present invention including a spacer;

5A to 5H are cross-sectional views illustrating a manufacturing process of an array substrate for a liquid crystal display device including a spacer according to a process sequence of the present invention.

<Short description of the symbols in the drawings>

100: substrate 101: gate wiring

102 gate electrode 104 gate insulating film

106: active layer 108: ohmic contact layer

110: data wiring 112: source electrode

114: drain electrode 116: protective film

120: transparent electrode layer 122`: PR layer

200: inkjet nozzle 300: spacer material

Claims (8)

delete delete delete delete delete  A first mask process step of forming a gate electrode and a gate wiring on the substrate; Forming a gate insulating film on an entire surface of the substrate on which the gate wiring and the gate electrode are formed; A second mask process step of forming an active layer and an ohmic contact layer on the gate insulating layer on the gate electrode; A third mask process step of forming a source electrode in contact with the ohmic contact layer, a drain electrode spaced apart from the predetermined distance, and a data line connected to the source electrode; Forming a passivation layer on the entire surface of the substrate on which the source and drain electrodes are formed, and exposing a portion of the drain electrode; Forming a transparent metal layer on an entire surface of the substrate on which the protective film is formed; Applying a photoresist layer on the transparent metal layer; Placing a mask including a transmissive part and a blocking part on an upper portion of the substrate on which the photoresist layer is applied, and exposing light to the upper part of the mask to expose a lower photoresist layer; Developing the exposed photoresist layer to remove a portion corresponding to the transmission portion; Filling the spacer material in the transmissive portion corresponding to the gate wiring with an inkjet method and curing the spacer material; Removing the transparent electrode exposed between the remaining PR layers; A fifth mask process of removing the remaining PR layer to form a pixel electrode in contact with the drain electrode and extending through the pixel region to an upper portion of the gate wiring, and a patterned spacer on the pixel electrode extending to the gate wiring; step Array substrate manufacturing method for a liquid crystal display device comprising a. The method of claim 6, And the pixel electrode extends over a portion of the data line. The method of claim 7, wherein And forming a patterned spacer on the pixel electrode extending above the data line.