KR101246570B1 - Method for fabricating liquid crystal display device - Google Patents

Abstract

The present invention relates to a manufacturing method of a liquid crystal display device, wherein the configuration of the liquid crystal display device to which the In Plane Switching (IPS) and the FFS (Fringe Field Switching) is applied comprises the steps of: providing a first substrate; Providing a second substrate; Forming a gate electrode and a common electrode on the second substrate; Forming a conductive layer and an active layer on the second substrate; Depositing a transparent electrode on the second substrate; Forming a source / drain electrode and a pixel electrode by applying a diffraction mask on the second substrate; and injecting a liquid crystal after bonding the first substrate and the second substrate to each other. The present invention can eliminate the parasitic capacitance between the data wiring and the gate wiring by using the conventional photo process only in the last step of depositing the transparent electrode, thereby improving the cross talk problem of the signal and further improving the data. The image quality can be improved by removing the amount of variation due to misalignment between the wiring and the pixel electrode, and finally, the panel characteristics of high aperture ratio can be realized by securing a margin for reducing light leakage of the channel portion.

Printing, wide viewing angle compensation design

Description

Manufacturing method of liquid crystal display device {METHOD FOR FABRICATING LIQUID CRYSTAL DISPLAY DEVICE}

1 is a plan view showing a part of an array substrate of a general transverse electric field type liquid crystal display device

2 is a plan view showing a part of an array substrate of a liquid crystal display of the present invention.

3A to 3I are cross-sectional views illustrating a manufacturing process of a TFT array substrate according to the present invention.

※※ Description of symbols on the main parts of the drawings ※※

112: roller 114: resist formed from cliché

116: resist in contact with the glass substrate 118: metal layer

120: glass substrate 122: gate electrode

124: common electrode 126: gate insulating film

128a: active layer after primary etching 128b: active layer pattern after secondary

130a: conductive layer after primary etching 130b: source / drain electrode

132: transparent electrode layer 132a: transparent electrode after primary etching

134: photoresist 134a: photoresist after diffraction exposure

134b: photoresist after ashing

The present invention relates to a method of manufacturing a liquid crystal display device. More specifically, the present invention relates to a method for manufacturing a thin film transistor array (TFT-array) substrate in an IPS (In Plane Switching) and FFS (Fringe Field Switching) type liquid crystal display device. Fabrication is performed using a printing method, and a source / drain electrode and a pixel electrode are formed by applying a diffraction mask on a substrate after depositing a transparent electrode.

Recently, with increasing interest in information displays and increasing demands for using portable information carriers, lightweight flat panel displays, which replace the conventional display device, the cathode ray tube (CRT); The research and commercialization of FPD) is focused on. Particularly, among such flat panel display devices, a liquid crystal display (LCD) is an apparatus for displaying an image using the optical anisotropy of a liquid crystal, and is excellent in resolution, color display and picture quality and is actively applied to a notebook or a desktop monitor have.

At this time, a driving method generally used in the liquid crystal display device is a twisted nematic (TN) method for driving nematic liquid crystal molecules in a vertical direction with respect to a substrate, but the liquid crystal display device of the method has a narrow viewing angle of about 90 degrees. Has its drawbacks. This is due to the refractive anisotropy of the liquid crystal molecules because the liquid crystal molecules oriented horizontally with the substrate are oriented almost perpendicular to the substrate when a voltage is applied to the liquid crystal display panel.

On the other hand, in contrast, the IPS scheme is driven in a horizontal direction to improve the viewing angle to 170 degrees or more, and will be described in detail below.

FIG. 1 is a plan view showing a part of an array substrate of a general IPS type liquid crystal display device. In an actual liquid crystal display device, N gate lines and M data lines cross each other to provide N × M pixels. Only one pixel is shown in the figure.

As shown in the drawing, a gate line 16 and a data line 17 are formed on the transparent glass substrate 10 to be arranged laterally and horizontally to define a pixel area. The gate line 16 and the data line 17 are formed. The thin film transistor 20 which is a switching element is formed in the cross | intersection area | region of the ().

In this case, the thin film transistor 20 includes a gate electrode 21 connected to the gate line 16, a source electrode 22 connected to the data line 17, and a drain electrode 23 connected to the pixel electrode line 18L. do. In addition, although not shown in the drawing, the thin film transistor 20 is a source electrode by an insulating film for insulating the gate electrode 21 and the source / drain electrodes 22 and 23 and a gate voltage supplied to the gate electrode 21. And an active layer, that is, a channel layer, which forms a conductive channel between the 22 and the drain electrode 23.

In the pixel region, the common electrode 8 and the pixel electrode 18 for generating a transverse electric field are alternately arranged in the longitudinal direction of the data line 17. In this case, the pixel electrode 18 is electrically connected to the pixel electrode line 18L connected to the drain electrode 23 through the first contact hole 40A, and the common electrode 8 is connected to the gate line 16. It is electrically connected through the common electrode line 8L and the second contact hole 40B arranged in parallel.

In addition, the common electrode 8 and the pixel electrode 18 are formed on the same plane with a transparent conductive material such as indium tin oxide (ITO).

On the other hand, as described above, the IPS type liquid crystal display device having a 2-ITO structure in which both the pixel electrode and the common electrode are formed as transparent electrodes has an aperture ratio which is increased since the electrodes are all formed as transparent electrodes in the pixel region which is an image display area. Since two kinds of electrodes are formed on the same layer, the electrode gap is uniformly formed, which is advantageous in that response speed and afterimages are obtained according to securing CD (critical dimension) uniformity.

However, variations in parasitic capacitance between the data wirings and the gate wirings and variations due to misalignment between the pixel electrodes are not eliminated, and still no cross talk and luminance improvement are achieved. As a result, the above problems are not particularly helpful for large area TV models that require wide viewing angle structures such as IPS mode.

Accordingly, an object of the present invention is to provide a method of manufacturing a liquid crystal display device which improves the above problems by using a photo process by diffraction exposure to pattern formation of a pixel electrode, which is the finest pattern among all the conventional processes.

The configuration of the thin film transistor liquid crystal display device of the IPS and FFS method according to the present invention comprises the steps of providing a first substrate; Providing a second substrate; Forming a gate electrode and a common electrode on the second substrate; Forming a conductive layer and an active layer on the second substrate; Depositing a transparent electrode on the second substrate; Forming a source / drain electrode and a pixel electrode by applying a diffraction mask on the second substrate; and injecting a liquid crystal after bonding the first substrate and the second substrate to each other.

Hereinafter, a method of manufacturing a liquid crystal display according to the present invention will be described in detail with reference to the accompanying drawings.
FIG. 2 is a plan view showing a part of an array substrate of an IPS type liquid crystal display device as a first embodiment according to the present invention.
Referring to the drawings, the TFT portion is formed at the intersection of the data line 130b and the gate line according to the present invention and is connected to a pixel electrode (not shown) for driving the liquid crystal cell. The data wiring is connected to the source region of the TFT semiconductor layer, the drain electrode (not shown) is connected to the drain region of the semiconductor layer, and the gate wiring has a protruding gate electrode 122 and a common electrode (not shown). The pixel electrode reacts with the common electrode formed on the same layer as the gate electrode 122 to form an electric field.

A method of manufacturing a liquid crystal display device according to the present invention will be described with reference to the drawings of FIGS. 3A to 3I based on the cut plane of FIG. 2.
As shown in FIG. 3A, in order to form the gate electrode and the common electrode, the interaction between the roller 112 and the cliché (not shown) is required. In other words, when the roller 112 is brought into contact with the cliché to interact, the resist pattern 114 remains on the roller. By rotating the resist pattern 114 on the roller formed through the above process on the substrate 120 on which the metal film 118 is deposited, the resist pattern 116 on the roller is reprinted onto the substrate 120.

Here, since the size of the roller is smaller than the substrate, the above process is repeated several times to form a resist pattern on the entire substrate. In particular, since the process of forming the resist pattern is characterized in that it has a directionality, the resist pattern for the gate electrode and the gate wiring is largely rotated in a direction parallel to the gate wiring, and smaller in the direction perpendicular to the line. It is worth noting that it is.

3B, the gate electrode 122 and the common electrode 124 are formed through an etching process. Subsequently, the gate insulating layer 126, the active layer, and the conductive layer are sequentially deposited on the substrate 120 on which the gate electrode 122 and the common electrode 124 are formed.

Thereafter, another type of photoresist is patterned on the region where the thin film transistor is to be formed again in the same manner as the roller printing method (not shown). Here again, the patterning process of the resist according to the printing method of the roller has the same orientation as the process of forming the gate electrode 122 and the common electrode 124. In other words, the rotation of the roller is increased in the direction parallel to the data line 130a, and the rotation of the roller is reduced in the direction perpendicular to the line.

3C, the conductive film and the active layer are etched according to the patterning of the resist to form the first etched conductive film 130a and the active layer 128a.

Next, although not separately shown in the drawings, a resist is printed on the substrate through the same roller printing method as described above to form a contact hole (not shown) for electrical contact with the gate pad part.

Finally, a transparent electrode layer 132 made of ITO or IZO or the like is deposited on the substrate on which the contact hole (not shown) is formed, and the photoresist 134 is formed on the transparent electrode layer 132. Is applied, and then the pixel electrode is formed through a subsequent detailed process using diffraction exposure of the mask as shown in FIG. 3E. In particular, it should be noted here that the resist is applied in the same manner as the conventional photo process.

Next, a process of forming a pixel electrode using diffraction exposure, which is the core of the present invention, will be described in detail.
As shown in FIG. 3E, a photoresist 134 is coated on the substrate on which the transparent electrode layer 132 is deposited. As shown in FIG. The resist of the portion is removed, and the portion where the source / drain and the pixel electrode are formed remains the resist, and only half of the resist is left in the portion where the channel is to be formed by diffraction exposure.

Then, as shown in FIG. 3G, the remaining portions except the remaining portions of the resist are etched preferentially, and then the side portions of the data line and the side portions of the source / drain conductive layer and the active layer are formed. A little etching is further performed to form the source / drain electrodes 130b and the active layer pattern 128b. This is called 'secondary etching' in the present invention.

As a result, since the data line and the pixel electrode are simultaneously defined in the transparent electrode forming step in the etching process step due to the diffraction exposure through the use of the mask, the conventional problem is eliminated by eliminating the variation due to misalignment. Solve the problem of luminance.

Thereafter, as shown in FIG. 3H, ashing of the remaining resist remaining at the site where the channel is to be formed and etching of the transparent electrode and the source / drain layer at the site where the channel is to be formed are performed.

Through the etching process, the channel layer related to the formation of the source / drain electrodes 130b is opened, and as a result, the source and drain electrodes 130b are electrically separated, so that only the channel layers are electrically connected. do. FIG. 3i shows the above result, and shows the state in which the source and drain electrodes are separated.

Finally, by stripping off the resist 134b remaining in the formation portion and data line portion of the source / drain electrode, the process of using diffraction exposure, which is the core of the present invention, is finished.

In fact, in addition to this, although not separately shown in the drawings, the TFT array substrate using the IPS and FFS schemes has alignment film deposition and rubbing on the substrate. Then, the upper panel is bonded to the color filter substrate, and then the LCD panel is formed including the liquid crystal injected between the two substrates.

Therefore, the margin between the gate and the source / drain (or active layer) and the source / drain and pixel electrode margin required for the formation of the channel, which have been necessary for reducing the conventional light leakage, are used in the manufacturing process according to the present invention. As a result, the margin between the gate and the pixel electrode can be secured, and as a result, the margin is secured to allow the opening to be designed more widely.

As a result, the present invention eliminates the variation of parasitic capacitance between the data line and the gate wiring by using the photolithography process of the pixel electrode layer, thereby improving the cross talk problem. By eliminating the variation due to the arrangement, it is possible to realize a panel characteristic with improved image quality.

As a result, the above process is particularly required for a large area TV model that requires a wide viewing angle structure such as IPS mode, and this structure also advantageously uses the pixel portion, which is the finest pattern, as the photo layer.

Claims (9)

Providing a roller with a first substrate and a second substrate; Interacting the rollers in contact with the cliché, leaving a first resist pattern on the rollers; Forming a metal film on the second substrate; Rotating the first resist pattern on the roller to print the first resist pattern on the roller onto the second substrate; Etching the metal layer through an etching process using the first resist pattern to form a gate wiring, a gate electrode, and a common electrode; Removing the first resist pattern and sequentially forming a gate insulating film, an active layer, and a conductive film on the entire surface of the second substrate including the gate wiring, the gate electrode, and the common electrode; Printing a second resist pattern on the conductive layer; Etching the conductive layer and the active layer using the second resist pattern to form a conductive layer pattern and an active layer pattern; Removing the second resist pattern and forming a transparent electrode layer on an entire surface of the second substrate including the conductive layer pattern and the active layer pattern; Applying a photoresist on the transparent electrode layer; A photoresist pattern on the transparent electrode layer corresponding to a data formation region, a source / drain electrode formation region and a pixel electrode formation region, and a channel region through an exposure process of the photoresist to which a diffraction mask is applied and a removal process of the exposed photoresist portion; Forming a thickness of a portion of the photoresist pattern corresponding to the channel region to be smaller than a thickness of the portion corresponding to the data line forming region, the source / drain electrode forming region, and the pixel electrode forming region; Performing an ashing process to remove the photoresist pattern portion corresponding to the channel region to expose the transparent electrode layer; By using the photoresist pattern remaining after the ashing process, the side portion of the active layer pattern, the side portion of the conductive layer pattern, the transparent electrode layer, and the conductive layer pattern under the transparent electrode layer are etched to provide data wiring, Forming a source / drain electrode and a pixel electrode, and forming a channel in the active layer pattern; And And injecting liquid crystal after bonding the first substrate and the second substrate to each other. delete delete The method of claim 1, wherein the forming of the source / drain electrode and the pixel electrode is performed by removing a portion of the photoresist that is completely exposed by a UV beam and forming a portion of the source / drain electrode. The remaining portion, wherein the portion corresponding to the channel region further comprises the step of leaving half the photoresist. delete delete delete delete The liquid crystal of claim 1, wherein the forming of the source / drain electrode and the pixel electrode further comprises stripping the photoresist pattern remaining on the source / drain electrode and the pixel electrode. Method for manufacturing a display device.

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