KR100745412B1 - Reflecting plate of liquid crystal display device and fabricating method thereof - Google Patents

Abstract

The present invention forms a metal layer to be applied as a reflective electrode on the protective film of the lower plate of the liquid crystal display device, a photoresist film is formed on the metal layer and then selectively irradiated with ultraviolet rays through a mask having a transflective mask or a diffraction slit, The present invention relates to a reflective plate of a liquid crystal display device and a method of manufacturing the same, in which a pattern of a photoresist film having a continuous bend is formed, the photoresist film is etched, and then the metal layer is etched so that the metal layer has a continuous bend.

Description

Liquid crystal display device having a reflector and a manufacturing method thereof {REFLECTING PLATE OF LIQUID CRYSTAL DISPLAY DEVICE AND FABRICATING METHOD THEREOF}

1A to 1F are cross-sectional views showing an example of a method of manufacturing a reflecting plate of a conventional liquid crystal display device.

2A to 2D are cross-sectional views showing another example of a method of manufacturing a reflecting plate of a conventional liquid crystal display device.

3A to 3I are cross-sectional views showing an embodiment of the present invention.

FIG. 4 is a detailed sectional view of the lower plate of the liquid crystal display element in FIG. 3A; FIG.

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

30: lower plate 31 of the liquid crystal display element

32: metal layer 33: photoresist film

34: semi-transmissive mask A to D: semi-transmissive area

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device having a reflector and a method of manufacturing the same, and particularly, to a liquid crystal display device having a reflector that is suitable for reducing the number of masks used and improving light reflection efficiency and reliability. It is about.

In general, the reflection plate of the liquid crystal display device has been used a simple mirror (mirror), but in recent years to study the reflection plate having a variety of forms in order to secure high light reflection efficiency and excellent viewing angle characteristics, active research Representative forms corresponding to the concave-convex reflector.

The liquid crystal display device employing the concave-convex reflector is mainly focused on improving light reflection efficiency by using scattering characteristics of light reflected on the inclined surface of the reflector. Such a reflective plate of a conventional liquid crystal display device and a method of manufacturing the same will be described in detail with reference to the accompanying drawings.

An example of a reflective plate of a conventional liquid crystal display device and a method of manufacturing the same will be described with reference to the procedure cross-sectional view of FIGS. 1A to 1F.

First, as shown in FIG. 1A, a spin coating or roll coating method is applied on the substrate 10 to form a photoresist film 11 made of a polymer resin.

As shown in FIG. 1B, the photoresist film 11 is blocked with a mask 12 in which non-transmissive regions A to D are selectively formed, followed by irradiation with ultraviolet rays (arrows on the drawing). do.

As shown in FIG. 1C, the result of irradiating the ultraviolet light is developed to form a pattern of the photoresist film 11 remaining selectively on the substrate 10.

As shown in FIG. 1D, the resultant is heat-treated to soften the corner curvature of the photoresist film 11 pattern.

As shown in FIG. 1E, an overcoat layer 13 made of a polymer resin is formed by applying a spin coating method to the entire upper surface of the resultant.

As shown in FIG. 1F, a sputtering method is applied to the entire upper surface of the overcoat layer 13 to form a reflective electrode 14 having a reflector function using a material such as aluminum or silver having a high reflectance.

However, one example of the reflective plate of the conventional liquid crystal display device and the method of manufacturing the same as described above is the development of the photoresist film 11 or the edge bending softening or overcoat layer of the photoresist film 11 pattern remaining after the development ( 13) Since a complicated process such as formation is required, not only manufacturing is very difficult but also manufacturing cost increases due to an increase in the number of processes.

Therefore, in order to solve the problems as described above, a reflection plate of a liquid crystal display device having a surface with continuous curved portions that do not require the overcoat layer 13 and a manufacturing method thereof are proposed in Korean Patent Publication No. 1999-001427. It became. Referring to the water sectional view of Figs. 2a to 2d attached to another example of such a reflective plate and a manufacturing method of the conventional liquid crystal display device as follows.

First, as shown in FIG. 2A, a spin coating or roll coating method is applied on the substrate 20 to form a photoresist film 21 made of a polymer resin. In this case, the photoresist film 21 formed on the substrate 20 may be formed to a sufficient thickness to form a resin having a low decomposition degree by ultraviolet rays such as JNPC resin so as to remain as a lower passivation layer of the liquid crystal display device. .

As shown in FIG. 2B, the photoresist film 21 is blocked with a mask 22 in which non-transmissive regions A to D are selectively formed, followed by irradiation with ultraviolet rays (arrows on the drawing).

As shown in FIG. 2C, the UV-irradiated resultant is heat-treated and then partially developed to form irregularities of the photoresist film 21 having continuous bending on the substrate 20. At this time, since the photoresist film 21 applies a resin having a low decomposition degree by ultraviolet rays as described above, the region irradiated with ultraviolet rays is not completely removed by the development, and has a lower thickness than the region not irradiated with ultraviolet rays. It remains on the substrate 20.

As shown in FIG. 2D, a sputtering method is applied to the entire upper surface of the unevenness of the photoresist film 21 to form a reflective electrode 23 having a reflector function using a material such as aluminum or silver having a high reflectance.

However, another example of the reflective plate of the conventional liquid crystal display device and the manufacturing method as described above is applied to the protective film of the lower plate of the liquid crystal display device as a photoresist film 21 having a continuous bend on the substrate 20 Since the protective film on the bottom of the display device has a step, it may not be normally etched when forming a contact hole or pad hole of the drain, causing a fatal defect in driving the liquid crystal display device due to disconnection. There was a problem.

In addition, since the protective film of the lower plate of the liquid crystal display is selectively etched to form a continuous curve, it is affected by process variables (for example, exposure amount of ultraviolet rays, development time and etching conditions, etc.) and thus adversely affects the characteristics of the liquid crystal display. In order to make the protective film of the lower panel of the liquid crystal display device have irregularities, the photo-reflection profile is not uniform, so that the light reflection efficiency is reduced and the liquid crystal is reduced. It is difficult to accurately define the light efficiency characteristics of the display device, and thus there is a problem that the reliability is reduced.

As described above, a first mask for making the protective film have continuous bending, a second mask for forming a contact hole or a pad hole of the drain, and a third mask for patterning after forming the metal layer are required. There was a problem that caused an increase in manufacturing costs due to the increase.

SUMMARY OF THE INVENTION The present invention has been made to solve the conventional problems as described above, and an object of the present invention is to reduce the number of masks used by forming a metal layer having continuous unevenness on the protective film of the liquid crystal display device lower plate, and high light reflection. The present invention provides a liquid crystal display device having a reflection plate having efficiency and reliability, and a method of manufacturing the same.

First, a liquid crystal display device having a reflective plate for achieving the object of the present invention as described above is a lower plate of a liquid crystal display device on which a thin film transistor including a gate electrode, a gate insulating film, an active layer, and a source / drain electrode is formed on a glass substrate. A protective film formed on the upper portion; Formed to have a continuous bend on the upper portion of the protective film characterized in that it comprises a reflective electrode for reflecting the incident light.

In addition, the liquid crystal display device manufacturing method having a reflective plate for achieving the object of the present invention as described above is a liquid crystal display device in which a thin film transistor consisting of a gate electrode, a gate insulating film, an active layer and a source / drain electrode is formed on a glass substrate. Forming a protective film on the upper plate of the substrate; Selectively etching a portion of the passivation layer to expose a portion of the drain electrode formed on the lower plate of the liquid crystal display; Forming a metal layer to be applied as a reflective electrode for reflecting light incident on the resultant; Forming a photoresist film on the metal layer, selectively irradiating ultraviolet rays through a semi-transmissive mask, and developing the pattern to form a pattern of the photoresist film having continuous bending; Etching the pattern of the photoresist film to selectively expose the metal layer, and subsequently etching until the metal layer has a continuous bend; And a step of stripping the pattern of the photoresist film.

The liquid crystal display device having the reflective plate according to the present invention as described above and a method of manufacturing the same will be described in detail with reference to the process cross-sectional views of FIGS. 3A to 3I.

First, as shown in FIG. 3A, the passivation layer 31 is formed on the lower plate 30 of the liquid crystal display device. At this time, the protective film 31 formed on the lower plate 30 of the liquid crystal display device is applied to a material having excellent protective properties such as SiNx or acrylic.

Meanwhile, the lower plate 30 of the liquid crystal display device has a gate electrode 42, a gate insulating film 43, an active layer 44 and a source / source on the glass substrate 41 as shown in a detailed cross-sectional view of FIG. 4. A thin film transistor (TFT) consisting of the drain electrodes 45A / 45B is formed in advance.

As shown in FIG. 3B, a portion of the passivation layer 31 is selectively etched to expose a portion of the drain electrode 45B formed on the lower plate 30 of the liquid crystal display.

Then, as shown in Figure 3c to form a metal layer 32 to be applied as a reflective electrode for reflecting the light incident on the top of the result. In this case, the metal layer 32 may be formed in consideration of a sufficient thickness so that the uneven form formed through subsequent etching is not broken and can be continuous.

As shown in FIG. 3D, the photoresist film 33 is formed by applying a method such as spin coating or roll coating on the metal layer 32.

Then, as shown in Fig. 3E, the photoresist film 33 is blocked with a semi-transmissive mask 34 in which semi-transmissive regions A to D are selectively formed, followed by irradiation with ultraviolet rays (arrows on the drawing). do. In this case, a mask having diffraction slits may be applied instead of the transflective mask 34 to produce a transflective effect even when irradiated with ultraviolet rays, and the mask having the transflective mask 34 or the diffraction slits may be formed of the metal layer ( It is preferable to fabricate the photoresist film 33 on the region to be removed 32 so that ultraviolet rays are irradiated, so that the patterning of the metal layer 32 can be simultaneously performed through subsequent etching.

Then, as shown in FIG. 3F, the resulting UV-irradiated product is heat-treated and then developed to form the unevenness of the photoresist film 33 having continuous bending on the metal layer 32. At this time, the photoresist film 33 has a weak exposure intensity in the region irradiated with ultraviolet rays due to the application of the transflective mask 34 or a mask having a diffraction slit, so that the photoresist layer 33 is not completely removed by development, and the ultraviolet rays are not irradiated. It remains on the metal layer 32 with a thickness lower than that of the region.

3G, the pattern of the photoresist film 33 is etched to selectively expose the metal layer 32. At this time, when the photoresist film 33 is dry etched, the thickness gradually decreases along the unevenness, so that the photoresist film 33 in the region irradiated with ultraviolet rays is completely removed and the region of the region not irradiated with ultraviolet rays. The photoresist film 33 remains so that the metal layer 32 is selectively exposed.

As shown in FIG. 3H, the etching is continued until the metal layer 32 has a continuous bent portion 32a.

Then, as shown in Fig. 3I, the remaining pattern of the photoresist film 33 is stripped.

As described above, the reflective plate of the liquid crystal display device and the manufacturing method thereof according to the present invention are formed as a protective layer 31 of the liquid crystal display device, and then applied as a first mask and a reflective electrode for forming a contact hole or a pad hole of a drain. Since only the semi-permeable mask 34 for patterning the metal layer 32 is required while forming the metal layer 32 and then having the continuous curved portions 32a, the number of masks used in the related art can be reduced. do.

In the liquid crystal display device having the reflective plate and the method of manufacturing the same according to the present invention as described above, since the protective film of the lower plate of the liquid crystal display device has no curvature, the liquid crystal display is removed by eliminating etch defects for forming contact holes or pad holes in the drain. There is an effect that can prevent the occurrence of a fatal defect in the driving of the device.

In addition, by forming a protective film of the lower plate of the liquid crystal display, and forming a metal layer applied as a reflective electrode on the upper portion of the protective film and selectively etching to have a continuous bend, the characteristics of the liquid crystal display device even if affected by the process variables It is effective to alleviate the adverse effects, and after forming a high quality photoresist film on the metal layer applied as a reflective electrode, applying a semi-transmissive mask or a mask having a slit for diffraction, irradiating ultraviolet rays, and developing the photograph Since the etching profile is excellent, the light reflection efficiency is increased, and the light efficiency of the liquid crystal display device is accurately defined, thereby improving reliability.

In addition, since only two additional masks are required to form the reflective electrode on the lower plate on which the TFT array is formed, the number of masks can be reduced as compared with the prior art, thereby reducing the manufacturing cost.

Claims (7)

A lower plate of a liquid crystal display device having a thin film transistor including a gate electrode, a gate insulating film, an active layer, and a source / drain electrode formed on a glass substrate; A protective film formed on the upper plate; A contact formed on the protective film; And And a reflective electrode formed on the upper portion of the passivation layer including the contact and electrically connected to the drain electrode, the reflective electrode having a continuous bent portion. The liquid crystal display device of claim 1, wherein the protective layer is formed of SiNx or acrylic material. The liquid crystal display device of claim 1, wherein the continuous curved portion of the reflective electrode has a regular concave-convex shape. Forming a protective film on the lower plate of the liquid crystal display device having a thin film transistor including a gate electrode, a gate insulating film, an active layer, and a source / drain electrode formed on a glass substrate; Selectively etching a portion of the passivation layer to expose a portion of the drain electrode formed on the lower plate of the liquid crystal display; Forming a metal layer to be applied as a reflective electrode for reflecting light incident on the resultant; Forming a photoresist film on the metal layer, selectively irradiating ultraviolet rays through a semi-transmissive mask, and developing the photoresist film pattern having a continuous curved portion; Etching the photoresist film pattern to selectively expose the metal layer, and subsequently etching the metal layer until the metal layer has a continuous bent portion; And A method of manufacturing a liquid crystal display device with a reflecting plate, comprising the step of removing the photoresist film pattern. 5. The method of claim 4, wherein the protective film is formed of SiNx or acrylic material. The method of manufacturing a liquid crystal display device with a reflection plate according to claim 4, wherein a mask having a diffraction slit is applied in place of the transflective mask to selectively irradiate ultraviolet rays to the photoresist film. The method of claim 4 or 6, wherein the semi-transmissive mask or the mask having a diffraction slit selectively irradiates the photoresist film with ultraviolet light so that the metal layer applied to the reflective electrode through subsequent etching has a continuous bent portion. In addition, the method of manufacturing a liquid crystal display device with a reflector, characterized in that the photoresist film on the region where the metal layer is to be removed by irradiating ultraviolet light, so that the patterning of the metal layer can be performed simultaneously by subsequent etching.

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