KR100878202B1 - Semi-transmissive liquid crystal display device and manufacturing method thereof - Google Patents

Abstract

A semi-transmissive liquid crystal display device and a manufacturing method thereof are disclosed. An organic insulating layer including a display area and a pad area positioned outside the display area and having a contact hole exposing a portion of the pixel is formed on a substrate on which a pixel is formed in the display area. A transparent electrode is formed in a region other than the contact hole on the organic insulating layer. A barrier metal layer is formed on the contact hole and the transparent electrode. The reflective electrode is formed on the barrier metal layer in the same pattern as the barrier metal layer. The reflective electrode is connected to a portion of the pixel through the contact hole and has a transmission window that exposes a portion of the transparent electrode. The barrier metal layer is interposed between the transparent electrode and the reflective electrode to improve contactability, and the transparent electrode of the pixel contact hole region is removed and the pixel contact is realized by only the reflective electrode, thereby making it transparent in the pixel contact hole region due to the step of the organic insulating layer. The step opening of the electrode can be prevented from occurring.

Description

Transflective type liquid crystal display device and method of manufacturing the same

1 is a cross-sectional view of a transmissive liquid crystal display device having a circular pixel contact hole.

2 is a cross-sectional view of a transmissive liquid crystal display device having a C contact hole.

3A to 3C are cross-sectional views of a transflective liquid crystal display according to a conventional method.

4 is a cross-sectional view of a pixel contact region in the transflective liquid crystal display of FIG. 3.

5A to 5C are cross-sectional views of the transflective liquid crystal display according to the present invention.

6 is a cross-sectional view of a pixel contact region in the transflective liquid crystal display of FIG. 5.

7A to 12C are cross-sectional views illustrating a method of manufacturing a transflective liquid crystal display device according to the present invention.

<Explanation of symbols for main parts of the drawings>

100 substrate 102 gate electrode

104: gate terminal 106: gate insulating film

108: active pattern 110: ohmic contact pattern                 

112 source electrode 114 drain electrode

115: data terminal 116: protective film

118: first pad contact hole 119: second pad contact hole

120: organic insulating film 121: uneven portion

122: pixel contact hole 124: transparent electrode

125: gate pad electrode 126: data pad electrode

128: reflective electrode

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device and a method for manufacturing the same, and more particularly, a semi-transmissive liquid crystal display device and a method for manufacturing the same that can solve a step open problem of a transparent electrode in a structure using an organic insulating film as a protective film. It is about.

In today's information society, the role of electronic display devices becomes more and more important, and various electronic display devices are widely used in various industrial fields.

In general, an electronic display device refers to a device that transmits various information to a human through vision. In other words, an electronic display device may be defined as an electronic device that converts electrical information signals output from various electronic devices into optical information signals recognizable to human vision, and plays a role of a bridge between humans and electronic devices. It may be defined as.

In such an electronic display device, when an optical information signal is displayed by a light emitting phenomenon, it is called an emissive display device, and when a light modulation is displayed by reflection, scattering, or interference phenomenon, a light receiving display ( It is called a non-emissive display device. The light emitting display device, also called an active display device, includes a cathode ray tube (CRT), a plasma display panel (PDP), a light emitting diode (LED), and an electroluminescent display (electroluminescent display). display; ELD). In addition, the light receiving display device, which is a passive display device, includes a liquid crystal display (LCD), an electrochemical display (ECD), an electrophoretic image display (EPID), and the like.

Cathode ray tubes (CRTs) used in image display devices such as televisions and computer monitors occupy the highest share in terms of display quality and economy, but have many disadvantages such as heavy weight, large volume and high power consumption. .

However, due to the rapid progress of semiconductor technology, the electronic display device suitable for the new environment, that is, the thin and light, the low driving voltage and the low power consumption of the electronic device, according to the miniaturization, low voltage and low power of various electronic devices, and the miniaturization and light weight of the electronic device, The demand for flat panel display devices with features is rapidly increasing.                         

Among the various flat panel display devices currently developed, liquid crystal displays are thinner and lighter than other display devices, have low power consumption and low driving voltage, and are widely used in various electronic devices because they can display images close to cathode ray tubes. Is being used.

The liquid crystal display uses a transmissive liquid crystal display device that displays an image using a light source such as a backlight, a reflective liquid crystal display device using natural light, and a built-in light source of the display device itself in a dark place where an indoor or external light source does not exist. The display device may be classified into a transflective liquid crystal display device which operates in a transmissive display mode for displaying and operates in a reflective display mode for reflecting and displaying external incident light in an outdoor high illumination environment.

Among the liquid crystal display devices currently used, a device including a thin film transistor (TFT) for forming electrodes on two substrates and switching a voltage applied to each electrode is provided. It is usually formed in one of them. Liquid crystal displays using thin film transistors in the pixel portion are classified into an amorphous type and a polycrystalline type.

1 is a cross-sectional view of a transmissive liquid crystal display device having a circular pixel contact hole.

Referring to FIG. 1, a plurality of gate lines (not shown) and a plurality of data lines (not shown) are formed on a substrate 10 in a matrix form, and thin film transistors and indium-tin-oxide ( A transparent electrode 20 such as indium-tin-oxide (ITO) is formed. The transparent electrode 20 transmits light generated from the backlight positioned on the rear surface of the substrate 10 and simultaneously functions as a pixel electrode connected to the thin film transistors formed one by one in the pixel region of the substrate 10.

A gate insulating layer 12 is interposed between the gate line and the data line to prevent the gate line from contacting the data line. A gate electrode (not shown) of the thin film transistor is branched from the gate line, and a source electrode and a drain electrode 14 of the thin film transistor are branched from the data line.

A passivation layer 16 made of an inorganic insulating material such as silicon nitride is formed on the data line and gate insulating layer 12. The protective layer 16 is an insulating protective layer that prevents physical and chemical damage from the outside.

A circular pixel contact hole 18 is formed through the passivation layer 16 to expose a portion of the drain electrode 14. The transparent electrode 20 is connected to the drain electrode 14 of the thin film transistor through the contact hole 18. Here, reference numeral 22 denotes a contact area between the drain electrode 14 and the transparent electrode 20.

In the conventional transmissive liquid crystal display device in which a portion of the upper surface of the drain electrode 14 and the transparent electrode 20 contact each other, step opening of the transparent electrode 20 occurs due to poor step coverage of ITO. That is, since the transparent electrode 20 made of ITO is disconnected at the stepped portion of the contact hole 18, contact failure occurs between the drain electrode 14 and the transparent electrode 20, thereby preventing pixel driving.

Accordingly, a transmissive liquid crystal display device forming a pixel contact hole in a c shape has been proposed, and the structure thereof is illustrated in FIG. 2.                         

Referring to FIG. 2, a data line including a source electrode and a drain electrode 34 of a thin film transistor is formed on a substrate 30 on which a gate line including a gate electrode (not shown) is formed through a gate insulating layer 32. do.

A passivation layer 40 is formed on the data line and the gate insulating layer 32 having a contact hole 38 having a c shape exposing the top and side surfaces of the drain electrode 34. The transparent electrode 40 is formed on the passivation layer 40 to be connected to the drain electrode 34 of the thin film transistor through the contact hole 38. At this time, the transparent electrode 40 made of ITO is formed in contact with the upper surface and side surfaces of the drain electrode 34. Here, reference numeral 42 denotes a contact area between the drain electrode 34 and the transparent electrode 40.

Therefore, even if the transparent electrode 40 is disconnected at the stepped portion of the contact hole 38, contact defects are not generated because the drain electrode 34 and the transparent electrode 40 are in side contact as shown in FIG. Does not occur. However, when a misalignment occurs during the photolithography process for forming the contact hole 38, the active region formed between the gate electrode and the source / drain electrode 34 is out of the contact hole 38, so that light leakage occurs. Will occur. In addition, since the step on the substrate 30 is formed high, the alignment of the liquid crystal layer may not be performed properly, resulting in a decrease in the contrast ratio.

3A to 3C are cross-sectional views of a transflective liquid crystal display device according to a conventional method, and illustrate an amorphous silicon thin film transistor-liquid crystal display device having a bottom-gate structure. 3A shows a display area where a thin film transistor is formed, FIG. 3B shows a gate pad part, and FIG. 3C shows a data pad part.                         

Referring to FIGS. 3A to 3C, after depositing a first metal film on a substrate 50 made of an insulating material such as glass, quartz, or sapphire, patterning the first metal film by a photolithography process to extend the film in a first direction. A gate line including a gate line (not shown), a gate electrode 52 branched from the gate line, and a gate terminal 53 connected to an end of the gate line are formed.

A gate insulating film 54 made of silicon nitride is deposited on the substrate on which the gate wiring is formed, and an amorphous silicon film and an n ⁺ doped amorphous silicon film are sequentially deposited thereon. Subsequently, the n ⁺ doped amorphous silicon film and the amorphous silicon film are successively patterned by a photolithography process to form an active pattern 56 made of an amorphous silicon film and an ohmic contact pattern 58 made of n ⁺ doped amorphous silicon film. do.

After depositing a second metal layer on the ohmic contact pattern 58 and the gate insulating layer 54, the second metal layer is patterned by a photolithography process, and the data line extends in a second direction perpendicular to the gate line. And a source line 60 and a drain electrode 62 branched from the data line, and a data line 64 including a data terminal 64 connected to an end of the data line. Subsequently, the ohmic contact pattern 58 exposed between the source electrode 60 and the drain electrode 62 is dry-etched to complete the thin film transistor.

After forming a protective film 66 made of an inorganic insulating material such as silicon nitride on the data line and the gate insulating film 54, the protective film 66 on the drain electrode 62 is removed by a photolithography process. First and second pad contact holes 67 and 68 exposing the gate terminal 53 and the data terminal 64 are formed, respectively.

After forming the organic insulating film 70 on the entire surface of the resultant, the contact hole 72 exposing the drain electrode 62 by removing the drain electrode 62 and the organic insulating film 70 of the pad portion in the exposure and development process To form. At the same time, a plurality of uneven parts 74 for light scattering are formed on the surface of the organic insulating layer 70. The organic insulating layer 70 serves as a protective film, and at the same time, increases the gap between the data line and the pixel electrode to increase the aperture ratio.

ITO is deposited on the contact hole 72 and the organic insulating layer 70 and patterned by the photolithography process to form a transparent electrode 76 connected to the drain electrode 62 through the contact hole 72. At the same time, a data pad connected to a gate pad electrode 77 connected to the gate terminal 53 through the first pad contact hole 67 and a data terminal 64 through the second pad contact hole 68. Electrode 78 is formed.

A barrier metal layer (not shown) made of molybdenum (MoW) and a reflective film made of aluminum-neodymium (AlNd) were sequentially deposited on the entire surface of the resultant, and then the reflective film and the barrier metal layer were patterned by a photolithography process to contact holes. A reflective electrode 80 having a transmission window T ₁ connected to the drain electrode 62 through the 72 and exposing the transparent electrode 76 below is formed. At this time, the barrier metal layer serves to prevent ITO and aluminum from directly contacting and causing galvanic corrosion.

4 is a cross-sectional view of a pixel contact region in the transflective liquid crystal display shown in FIG. 3.

As shown in FIG. 4, in the transflective liquid crystal display device using the organic insulating film 70 together with the inorganic film 66 as a protective film, the transmissive type uses the protective film as a single layer of the inorganic film due to the thickness of the organic insulating film 70. As compared with the liquid crystal display, the step height is increased. In addition, in order to prevent burning of the organic insulating layer 70, an ITO film is deposited at a low temperature of 200 ° C. or lower to form a transparent electrode 76. Since the ITO film is crystalline at high temperature but amorphous at low temperature, it is deposited. Step applicability worsens. Thus, a step opening problem of the transparent electrode 76 made of ITO occurs on the organic insulating layer 70.

In order to solve the step opening problem of the transparent electrode 76, as shown in FIG. 2, when the contact hole 72 is formed in the shape of c, the step of the organic insulating layer 70 becomes too large and the liquid crystal layer is not aligned. Light leakage occurs in the black mode, which lowers the contrast ratio.

Accordingly, one object of the present invention is to use an organic insulating film as a protective film and to improve contact between the transparent electrode and the reflective electrode when the transparent electrode and the reflective electrode are contacted, and a semi-transmissive type that can solve the step opening problem of the transparent electrode. It is to provide a liquid crystal display device.

Another object of the present invention is to provide a semi-transmissive liquid crystal display that uses an organic insulating film as a protective film and improves contact between the transparent electrode and the reflective electrode when the transparent electrode and the reflective electrode are in contact, and solves the step opening problem of the transparent electrode. It is to provide a method of manufacturing a device.

According to an aspect of the present invention, there is provided a display device including: a substrate including a display area and a pad area disposed outside the display area, wherein a pixel is formed in the display area; An organic insulating layer formed on the pixel and the substrate and having a contact hole exposing a portion of the pixel; A transparent electrode formed on an area of the organic insulating layer except for the contact hole; A barrier metal layer formed on the contact hole and the transparent electrode; And a reflective electrode formed on the barrier metal layer in the same pattern as the barrier metal layer and having a transmission window connected to a portion of the pixel through the contact hole and exposing a portion of the transparent electrode. A transmissive liquid crystal display device is provided.

In accordance with another aspect of the present invention, there is provided a method including forming a pixel on a display area of a substrate including a display area and a pad area disposed outside the display area; Forming an organic insulating layer on the pixel and the substrate; Etching the organic insulating layer to form a contact hole exposing a portion of the pixel; Forming a transparent electrode on a region excluding the contact hole on the organic insulating layer; Forming a barrier metal layer on the contact hole and the transparent electrode; And forming a reflective electrode on the barrier metal layer in the same pattern as the barrier metal layer, the reflective electrode having a transmission window connected to a portion of the pixel through the contact hole and exposing a portion of the transparent electrode. A method for manufacturing a transflective liquid crystal display device is provided.

According to the present invention, in a transflective liquid crystal display device using an organic insulating film as a protective film and having a multi-pixel pixel electrode, the multi-film pixel electrode is formed in a structure in which a transparent electrode is located in a lower layer, and between the transparent electrode and the reflective electrode The transparent electrode and the reflective electrode are directly contacted through the barrier metal layer. The transparent electrode of the pixel contact hole region is removed and the pixel contact is realized using only the reflective electrode.

Therefore, the barrier metal layer is interposed between the transparent electrode and the reflective electrode to improve the contact between the transparent electrode and the reflective electrode, and prevent the step opening of the transparent electrode from occurring in the pixel contact hole region due to the step of the organic insulating layer. have.

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

5A to 5C are cross-sectional views of a transflective liquid crystal display device according to the present invention, and show an amorphous silicon thin film transistor-liquid crystal display device having a bottom-gate structure. 5A shows a display area where a thin film transistor is formed, FIG. 5B shows a gate pad part, and FIG. 5C shows a data pad part.

Referring to FIGS. 5A to 5C, a gate wiring made of a first metal film such as chromium (Cr) / aluminum-neodymium (AlNd) is formed on an insulating substrate 100 such as glass, quartz, and sapphire. The gate line includes a gate line (not shown) extending in a first direction, a gate electrode 102 of the thin film transistor branched from the gate line, and a gate terminal 104 connected to an end of the gate line.

A gate insulating layer 106 made of an inorganic material, for example, silicon nitride, is formed on the gate wiring and the substrate 100. The active pattern 108 made of amorphous silicon and the ohmic contact pattern 110 made of amorphous silicon doped with n ⁺ are sequentially stacked on the gate insulating layer 106 on the gate electrode 102.

In addition, a data line made of a second metal film such as chromium (Cr) or aluminum (Al) is formed on the gate insulating film 106. The data line extends in a second direction crossing the gate line and divides the pixel portion together with the gate line, and a first electrode (a source electrode or a drain) of a thin film transistor branched from the data line. Electrode) 112 and a second electrode (drain electrode or source electrode) 114, and a data terminal 115 connected to an end of the data line. Hereinafter, the first electrode 112 is called a source electrode, and the second electrode 114 is called a drain electrode. Therefore, a thin film including a gate electrode 102, a gate insulating layer 106, an active pattern 108, an ohmic contact pattern 110, a source electrode 112, and a drain electrode 114 is formed on the display area of the substrate 100. Transistor 150 is formed.

The passivation layer 116 made of an inorganic insulating material such as silicon nitride and the organic insulating layer 120 made of a photosensitive acrylic resin are sequentially stacked on the data line and the gate insulating layer 106. In general, a sufficient gap must be maintained between the pixel electrode and the data line to increase the aperture ratio by overlapping the pixel electrode with the gate line and the data line, respectively. However, the protective film 116 made of silicon nitride has a limit in increasing its thickness due to the stress of the film itself. Therefore, when the passivation layer 116 is formed to a thickness suitable for performing a passivation role, and then the organic insulation layer 120 is formed thick, the organic insulation layer 120 acts as a passivation layer and between the data line and the pixel electrode. To increase the gap. That is, since the organic insulating layer 120 has a thick thickness of 2 μm or more and a low dielectric constant, the pixel electrode is separated from the gate line and the data line by suppressing generation of parasitic capacitance between the data line and the pixel electrode and maintaining a sufficient gap. It can be formed so as to overlap the thin film transistor-liquid crystal display device having a high aperture ratio. Preferably, the organic insulating layer 120 is formed only in the display region, and only the protective layer 116 made of an inorganic insulating material is formed in the pad region in order to secure the reliability of the transistor and the pad electrode and improve the adhesion of the chip on glass (COG) bonding. do.

A pixel electrode connected to the drain electrode 114 is formed on the organic insulating layer 120 through the pixel contact hole 122 formed through the passivation layer 116 and the organic insulating layer 120 on the drain electrode 114. In addition, the gate terminal 104 may be formed through the first pad contact hole 118 and the second pad contact hole 119 formed through the gate insulating layer 106 and the passivation layer 116 on the gate terminal 104 and the data terminal 115. The gate pad electrode 125 and the data pad electrode 126 connected to the 104 and the data terminal 115 are formed, respectively. The gate pad electrode 125 applies a scan voltage to the gate electrode 102, and the data pad electrode 126 applies a signal voltage to the source electrode 112.

The pixel electrode is a transparent electrode 124 made of a conductive oxide film such as ITO, a barrier metal layer such as molybdenum (MoW) (not shown), and a metal having high reflectivity such as aluminum-neodymium (AlNd) or silver (Ag). It is composed of a multi-layer of the reflective electrode 128 made, the transparent electrode 124 is a structure located in the lower layer. In this case, the transparent electrode 124 and the reflective electrode 128 are in direct contact with the barrier metal layer.

The pixel electrode is formed in a pixel portion partitioned by a gate line and a data line. The pixel electrode receives an image signal from the thin film transistor 150 and generates an electric field together with a transparent common electrode (not shown) of the upper substrate (ie, the color filter substrate).

The transparent electrode 124 transmits light incident through the substrate 10 from a backlight disposed on the rear surface of the substrate 100, and is simultaneously connected to the thin film transistors 150 formed one by one in the pixel region of the substrate 100. It serves as an electrode. The reflective electrode 128 reflects light incident from the outside through the substrate 100 and simultaneously serves as a pixel electrode. That is, the region where only the transparent electrode 124 is present is provided to the transmission window T ₂ , and other portions are provided to the reflection window. The barrier metal layer serves to prevent galvanic electro corrosion from occurring between the transparent electrode 124 and the reflective electrode 128.

According to the present exemplary embodiment, the gate pad electrode 125 and the data pad electrode 126 are formed of the same layer as the transparent electrode 124. When the pad electrode is formed of the same layer as the reflective electrode 128 made of metal, metal corrosion occurs when the pad electrode is connected to the external driving integrated circuit (IC) in a COG method, causing reliability problems. However, when the pad electrodes 125 and 126 are formed of a conductive oxide film such as ITO constituting the transparent electrode 124 as in the present embodiment, metal corrosion does not occur during COG bonding, thereby improving pad reliability. .

6 is a cross-sectional view of a pixel contact region in a transflective liquid crystal display according to the present invention.

Referring to FIG. 6, the transparent electrode 124 of the multilayer pixel electrode is formed only in a region other than the pixel contact hole 122 so that the transparent electrode 124 is not in direct contact with the drain electrode 114 of the thin film transistor. That is, only the reflective electrode 128 is in direct contact with the drain electrode 114 of the thin film transistor through the pixel contact hole 122. In this case, since the transparent electrode 124 and the reflective electrode 128 are conductive to each other through the barrier metal layer, the transparent electrode 124 and the reflective electrode 128 do not directly affect the pixel driving even if the transparent electrode 124 is not in direct contact with the drain electrode 114.

Therefore, since the transparent electrode 124 having poor step coverage, such as ITO, is not formed in the pixel contact hole region 122, the step opening problem does not occur in the pixel contact hole region 122.

7A to 12C are cross-sectional views illustrating a method of manufacturing a transflective liquid crystal display device according to the present invention. Here, FIG. A shows a display area where a thin film transistor is formed, and b and c show a gate pad portion and a data pad portion, respectively.

Referring to FIGS. 7A to 7C, a first metal film made of about 500 ns of chromium (Cr) and about 2500 ns of aluminum-nadium (AlNd) is formed on a substrate 100 made of an insulating material such as glass, quartz, or ceramic. After deposition, a gate line (not shown) extending in the first direction by patterning the first metal layer by a photolithography process using a first mask, the gate electrode 102 of the thin film transistor branched from the gate line, and A gate wiring including a gate terminal 104 connected to an end of the gate line is formed. At this time, the gate electrode 102 is preferably formed so that the sidewall has a tapered profile in consideration of the step coverage of the films deposited thereon.

Silicon nitride is deposited on the entire surface of the substrate 100 on which the gate wiring is formed by a plasma-enhanced chemical vapor deposition (PECVD) method to form a gate insulating film 106.

8A to 8C, an active silicon layer, for example, an amorphous silicon film is deposited on the gate insulating layer 106 to a thickness of about 2000 microseconds by a PECVD method, and an ohmic contact layer, for example, an n ⁺ doped amorphous layer is deposited thereon. The silicon film is deposited to a thickness of about 500 GPa by PECVD. At this time, the active layer and the ohmic contact layer are deposited in-situ in the same chamber of the PECVD facility. Subsequently, the layers are patterned by a photolithography process using a second mask to form an active pattern 108 formed of an amorphous silicon film on the gate insulating film 106 above the gate electrode 102 and an n ⁺ doped amorphous silicon film. The ohmic contact pattern 110 is formed.

On the ohmic contact pattern 110 and the gate insulating layer 106, a second metal layer such as chromium (Cr), chromium-aluminum (Cr-Al), or chromium-aluminum-chromium (Cr-Al-Cr) may be formed in a range of about 1500 to about 500 nm. After deposition to a thickness of 4000 Å, the second metal film is patterned by a photolithography process using a third mask to form a data line (not shown) orthogonal to the gate line, a source electrode 112 and a drain branched from the data line. A data line including an electrode 114 and a data terminal 115 connected to an end of the data line is formed. Subsequently, the exposed ohmic contact pattern 110 between the source electrode 112 and the drain electrode 114 is removed by a reactive ion etching (RIE) method. As a result, the thin film transistor 150 including the gate electrode 102, the gate insulating layer 106, the active pattern 108, the ohmic contact pattern 110, the source electrode 112, and the drain electrode 114 is completed. In this case, a gate insulating layer 106 is interposed between the gate line and the data line to prevent the gate line from contacting the data line.

In this embodiment, the active pattern 108, the ohmic contact pattern 110 and the data wirings are formed using two masks. However, the Applicant forms the active pattern 108, the ohmic contact pattern 110 and the data wiring using one mask, thereby reducing the number of masks used to manufacture the thin film transistor-liquid crystal display device having a bottom-gate structure. Invented a method that can be reduced by the Republic of Korea Patent Application No. 1998-049710. This method is described in detail as follows.

First, an active layer, an ohmic contact layer, and a second metal film are sequentially deposited on the gate insulating layer 106. Applying a photoresist film on the second metal film and exposing and developing the photoresist film, the first portion having a first thickness and a second portion located on the channel portion of the thin film transistor and the data wiring portion and having a thickness greater than the first thickness. A photoresist pattern (not shown) is formed including the portion and the third portion from which the photoresist is completely removed. Then, the second metal film under the third portion, the ohmic contact layer and the active layer, the second metal film under the first portion, and the partial thickness of the second portion is etched to form the second metal film. A data line, an ohmic contact pattern 110 made of an n ⁺ doped amorphous silicon film, and an active pattern 108 made of an amorphous silicon film are simultaneously formed. Subsequently, when the remaining photoresist pattern is removed, the active pattern 108, the ohmic contact pattern 110, and the data line are simultaneously formed using one mask.

9A to 9C, a protective film 116 is formed by depositing an inorganic insulating material such as silicon nitride on the entire surface of the substrate 100 on which the thin film transistor 150 is formed to a thickness of about 2000 μs. The protective layer 116 is an insulating protective layer that prevents physical and chemical damage from the outside, and serves to secure reliability of transistors and pads and to improve adhesion of integrated circuit portions during COG bonding. Subsequently, the protective layer 116 and the gate insulating layer 106 are etched by a photolithography process using a fourth mask to form a contact hole 117 exposing the drain electrode 114. At the same time, a first pad contact hole 118 and a second pad contact hole 119 are formed to expose the gate pad 104 and the data pad 115, respectively.

Referring to FIGS. 10A to 10C, an organic insulating material having a low dielectric constant, such as a photosensitive acrylic resin, may be thickly coated to a thickness of 2 μm or more, preferably 3.3 μm, on the entire surface of the resultant contact hole. 120). Since the organic insulating layer 120 suppresses generation of parasitic capacitance between the pixel electrode and the data line, the organic insulating layer 120 is formed to overlap the gate line and the data line, thereby increasing the aperture ratio.

Subsequently, a fifth mask (not shown) having a pattern corresponding to the pixel contact hole 122 is disposed on the organic insulating layer 120 to form the pixel contact hole 122 in the organic insulating layer 120. First, the organic insulating layer 120 on the drain electrode 114 and the organic insulating layer 120 of the gate pad part and the data pad part are exposed through a full exposure process. Subsequently, after placing the sixth mask (not shown) for forming the microlens on the organic insulating layer 120, the organic insulating layer in the portion except for the contact hole 122 is subjected to a lens exposure process using the sixth mask. 120 is secondarily exposed. Then, when the development process is performed using a tetramethyl-ammonium hydroxide (TMAH) developer, the pixel contact hole 122 and the plurality of irregularities 121 extending from the contact hole 117 to expose the drain electrode 114 are exposed. ) Are formed. At this time, the organic insulating layer 122 of the gate pad part and the data pad part is removed.

Subsequently, after curing for 100 minutes at a temperature of about 130 ° C. to 230 ° C. for reflow and curing of the organic insulating layer 120, the chromium film is time-etched for about 7 seconds to improve pixel contact characteristics. The surface of the exposed drain electrode 114 is cleaned by etching by a time etching method. Thereafter, a transparent conductive film 123 such as ITO is deposited on the pixel contact hole 122 and the organic insulating film 120 at a temperature of about 200 ° C. or less, preferably about 150 ° C., at a thickness of about 400 Pa. .

In the present exemplary embodiment, the protective layer 116 on the drain electrode 144 is first etched and then the pixel contact hole 122 is formed through the exposure / development process of the organic insulating layer 120. The pixel contact hole 122 exposing the drain electrode 144 may be formed by removing the organic insulating layer 120 on the 144 and then etching the passivation layer 166 by a photolithography process using another mask.

11A to 11C, the transparent conductive layer 123 is patterned by a photolithography process and a wet etching process using a seventh mask to form a transparent electrode 124 serving as a transmission window. In this case, the transparent conductive film 123 in the pixel contact hole 122 region is removed.

At the same time, the gate pad electrode 125 and the second pad contact hole 119 are connected to the gate terminal 104 through the first pad contact hole 118 to apply a scan voltage to the gate electrode 102. The data pad 115 is connected to the data terminal 115 to form a data pad electrode 126 for applying a signal voltage to the source electrode 112.

12A to 12C, an etching rate similar to that of the reflective film is applied to an etchant for etching the reflective film constituting the reflective electrode on the front surface of the resultant product on which the transparent electrode 124 and the pad electrodes 125 and 126 are formed. A metal having, for example, molybdenum (MoW) is deposited to a thickness of about 500 kPa at a temperature of from room temperature to 150 ° C to form a barrier metal layer (not shown). Subsequently, aluminum-neodymium (AlNd) is deposited on the barrier metal layer to a thickness of about 1500 kPa at a temperature of from room temperature to 150 ° C to form a reflective film.

Subsequently, the reflective film and the barrier metal layer are patterned by a photolithography process and a wet etching process using an eighth mask to form the reflective electrode 128 in direct contact with the transparent electrode 124. In this case, the reflective electrode 128 is in direct contact with the drain electrode 114 of the thin film transistor through the pixel contact hole 122.

As described above, according to the present invention, in the transflective liquid crystal display device using the organic insulating film as the protective film and having the multi-pixel pixel electrode, the multi-layer pixel electrode is formed in a structure in which the transparent electrode is located in the lower layer, and the transparent electrode A barrier metal layer is interposed between and the reflective electrode. The transparent electrode of the pixel contact hole region is removed and the pixel contact is realized using only the reflective electrode.

Thus, the contact characteristic is improved between the transparent electrode and the reflective electrode. In addition, it is possible to prevent the step opening of the transparent electrode in the pixel contact hole region due to the step of the organic insulating layer.

As described above, although described with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and modified within the scope of the present invention without departing from the spirit and scope of the present invention described in the claims below. It will be appreciated that it can be changed.

Claims (14)

A substrate including a display area and a pad area disposed outside the display area, wherein a pixel is formed in the display area; An organic insulating layer formed on the pixel and the substrate and having a contact hole exposing a portion of the pixel; A transparent electrode formed on an area of the organic insulating layer except for the contact hole; A reflective electrode formed on the contact hole and the transparent electrode and having a transmission window connected to a portion of the pixel through the contact hole and exposing a portion of the transparent electrode; And And a barrier metal layer formed in the same pattern as the reflective electrode between the transparent electrode and the reflective electrode and in direct contact with the transparent electrode and the reflective electrode. The transflective liquid crystal display of claim 1, wherein the pixel is a thin film transistor. The semi-transmissive liquid crystal display device according to claim 1, further comprising a protective film made of an inorganic insulating material formed under the organic insulating film. The semi-transmissive liquid crystal display device according to claim 1, wherein a plurality of uneven parts are formed on a surface of the organic insulating film. The semi-transmissive liquid crystal display device according to claim 1, further comprising a pad electrode formed in the same layer as the transparent electrode on the pad region of the substrate. delete The method of claim 1, wherein the transparent electrode is formed of indium-tin-oxide (ITO), the barrier metal layer is formed of molybdenum (MoW), and the reflective electrode is formed of aluminum-neodymium (AlNd). Semi-transmissive liquid crystal display device. Forming a pixel on the display area of the substrate including a display area and a pad area disposed outside the display area; Forming an organic insulating layer on the pixel and the substrate; Etching the organic insulating layer to form a contact hole exposing a portion of the pixel; Forming a transparent electrode on a region excluding the contact hole on the organic insulating layer; Forming a barrier metal layer on the contact hole and the transparent electrode; And And forming a reflective electrode on the barrier metal layer in the same pattern as the barrier metal layer, the reflective electrode having a transmission window connected to a portion of the pixel through the contact hole and exposing a portion of the transparent electrode. A method of manufacturing a transflective liquid crystal display device. 10. The method of claim 8, further comprising forming a protective film made of an inorganic insulating material on the pixel and the substrate before forming the organic insulating film. The method of claim 8, wherein, in the forming of the contact hole, a plurality of uneven parts are formed on a surface of the organic insulating layer. The method of claim 8, wherein in the forming of the transparent electrode, a pad electrode is formed on the pad region of the substrate in the same layer as the transparent electrode. delete The method of claim 8, wherein the transparent electrode is formed of indium tin oxide (ITO), the barrier metal layer is formed of molybdenum (MoW), and the reflective electrode is formed of aluminum-neodymium (AlNd). A method of manufacturing a transflective liquid crystal display device. A substrate including a display area and a pad area disposed outside the display area, wherein a pixel is formed in the display area; An organic insulating layer formed on the pixel and the substrate and having a contact hole exposing a portion of the pixel; A transparent electrode formed on an area of the organic insulating layer except for the contact hole; And And a reflective electrode formed on the contact hole and the transparent electrode so as to be connected to a portion of the pixel through the contact hole, and formed to be in direct contact with the transparent electrode and having a transmission window exposing a portion of the transparent electrode. Semi-transmissive liquid crystal display device characterized in that.

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