Abstract:
A trans-reflective LCD and a manufacturing method thereof are provided to simplify a manufacturing process and improve yield by reducing the number of masks and implement high definition by preventing wavy noise. A first substrate divided into a pixel unit and first and second pad units is provided. Through a first mask process, a gate electrode and a gate line are formed in the pixel unit of the first substrate. Through a second mask process, an active pattern of an island type is formed on the gate electrode in a state when a first insulating layer is interposed. On the active pattern, an n+ amorphous silicon thin film pattern and a conductive layer pattern are formed. Through a third mask process, a source electrode and a drain electrode are formed in the pixel unit of the first substrate. A data line crosses the gate line to define a pixel area comprising a reflection unit and a transmission unit. Through the third mask process, a pixel electrode comprising a transparent conductive layer is formed in the transmission unit of the pixel area. Through a fourth mask process, a second insulating layer is formed on the first substrate. Through a fifth process, a reflection electrode comprising an opaque conductive layer is formed in the reflection unit of the pixel area. The first substrate is deposited with a second substrate.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application claims priority under 35 U.S.C. 119 and 35 U.S.C. 365 to Korean Patent Application No. 10-2006-0134202 filed on Dec. 26, 2006, which is hereby incorporated by reference in its entirety. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     Embodiments of the present invention relate to a display device and, more particularly, to a transflective liquid crystal display (LCD) device and a fabrication method thereof. Although embodiments of invention are suitable for a wide scope of applications, it is particularly suitable for simplifying a fabrication process and improving production yield by reducing the number of masks and also suitable for implementing high picture quality by preventing generation of wavy noise. 
     2. Description of the Related Art 
     As the consumer&#39;s interest in information displays is growing and the demand for portable (mobile) information devices is increasing, research and commercialization of light and thin flat panel displays (“FPD”) has increased. 
     Among FPDs, the liquid crystal display (“LCD”) is a device for displaying images by using optical anisotropy of liquid crystal. LCD devices exhibit excellent resolution and color and picture quality, so it is widely used for notebook computers or desktop monitors, and the like. 
     The LCD includes a color filter substrate, an array substrate and a liquid crystal layer formed between the color filter substrate and the array substrate. 
     An active matrix (AM) driving method commonly used for the LCD is a method in which liquid crystal molecules in a pixel part are driven by using amorphous silicon thin film transistors (a-Si TFTs) as switching elements. 
     In the fabricating process of the LCD, a plurality of masking processes (namely, photographing processes) are performed to fabricate the array substrate including the TFTs, so a method for reducing the number of masking process will increase productivity. 
     The general structure of the LCD will now be described in detail with reference to  FIG. 1 . 
       FIG. 1  is an exploded perspective view showing a general LCD. 
     As shown in  FIG. 1 , the LCD includes a color filter substrate  5 , an array substrate  10  and a liquid crystal layer  30  formed between the color filter substrate  5  and the array substrate  10 . 
     The color filter substrate  5  includes a color filter (C) including a plurality of sub-color filters  7  that implement red, green and blue colors, a black matrix  6  for dividing the sub-color filters  7  and blocking light transmission through the liquid crystal layer  30 , and a transparent common electrode  8  for applying voltage to the liquid crystal layer  30 . 
     The array substrate  10  includes gate lines  16  and data lines  17  which are arranged vertically and horizontally to define a plurality of pixel regions (P), TFTs, switching elements, formed at respective crossings of the gate lines  16  and the data lines  17 , and pixel electrodes  18  formed on the pixel regions (P). 
     The color filter substrate  5  and the array substrate  10  are attached in a facing manner by a sealant (not shown) formed at an edge of an image display region to form a liquid crystal panel, and the attachment of the color filter substrates  5  and the array substrate  10  is made by an attachment key formed on the color filter substrate  5  or the array substrate  10 . 
     The general LCD expresses an image by light emitted from a light source such as a backlight positioned at a lower portion of a liquid crystal panel. However, the actual amount of light transmitted through the liquid crystal panel is about 7% of the light generated by the backlight, causing severe loss of light, so power consumption by the backlight is high. 
     Recently, to solve the problem of the high power consumption, a reflective LCD that does not use such a backlight has been studied. The transflective LCD uses natural light as a means for expressing an image, without such power consumption caused by the backlight, so it can be used in a carried-around state for a long time. 
     Unlike an existing transmissive LCD, the reflective LCD uses an opaque material having reflectivity characteristics at a pixel region to reflect light made incident from an external source to thus express an image. 
     However, because natural or an artificial light source does not exist always, the reflective LCD can be used during day time when natural light is present or in an office or in a building where an external artificial optical source is provided. Namely, the reflective LCD cannot be used in a dark environment in which natural light is not present. 
     To solve the problem, a transflective LCD, which combines the advantages of the reflective LCD using natural light and the transmissive LCD that uses a backlight, is being actively studied. The transflective LCD can be changed to a reflective mode and a transmissive mode according to a user intention, and light of the backlight, an external natural light source or an artificial light source can be all used, so power consumption can be reduced without being limited to the surrounding environments. 
       FIGS. 2A to 2F  are cross-sectional views sequentially showing a fabrication process of an array substrate of the general transflective LCD. 
     As shown in  FIG. 2A , a gate electrode  21  made of a conductive material is formed by using a photolithography process (a first masking process) on a substrate. 
     Next, as shown in  2 B, a first insulation film  15   a , an amorphous silicon thin film and an n+ amorphous silicon thin film are sequentially deposited over the entire surface of the substrate  10  with the gate electrode  21  formed thereon, and the amorphous silicon thin film and the n+ amorphous silicon thin film are selectively patterned by using the photolithography process (a second masking process) to form an active pattern  24  formed of the amorphous silicon thin film on the gate electrode  21 . 
     In this case, the n+ amorphous silicon thin film pattern  25  which has been patterned in the same form as the active pattern  24  is formed on the active pattern  24 . 
     Thereafter, as shown in  FIG. 2C , a conductive metal material is deposited over the entire surface of the array substrate  10  and then selectively patterned by using the photolithography process (a third masking process) to form a source electrode  22  and a drain electrode  23  at an upper portion of the active pattern  24 . At this time, a certain portion of the n+ amorphous silicon thin film pattern formed on the active pattern  24  is removed through the third masking process to form an ohmic-contact layer  25 ′ between the active pattern  24  and the source and drain electrodes  22  and  23 . 
     Subsequently, as shown in  FIG. 2D , a second insulation film  15   b , namely, an organic insulation film such as acryl, is deposited over the entire surface of the array substrate  10  with the source electrode  22  and the drain electrode  23  formed thereon, and a portion of the second insulation film  15   b  is removed through the photolithography process (a fourth masking process) to form a contact hole  40  exposing a portion of the drain electrode  23 . 
     In this case, as shown, the surface of the second insulation film  15   b  is formed to be irregular (i.e., uneven, rough, jagged, bumpy, undulated, wavy, rippled, furrowed, ruffed, indented, serrated, etc.) to enhance reflection efficiency in the reflective mode. 
     As shown in  FIG. 2E , a conductive metal material having good reflectivity is deposited over the entire surface of the array substrate  10  with the second insulation film  15   b  formed thereon, and then selectively patterned by using the photolithography process (a fifth making process) to form a reflective electrode  18   b  electrically connected with the drain electrode  23  via the contact hole  40 . 
     As shown in  FIG. 2F , a transparent conductive metal material is deposited over the entire surface of the array substrate  10 , and then, a pixel electrode  18   a  is formed over the entirety of the pixel region including a reflective part where the reflective electrode  18   b  has been formed, by using a photolithography process (a sixth masking process). 
     As mentioned above, in fabricating the array substrate including TFTs of the general transflective LCD, a total of six photolithography processes are necessarily performed. That is, the general transflective LCD requires more photolithography processes compared to that of the transmissive LCD. 
     The photolithography process is a process of transferring a pattern formed on a mask onto the substrate on which a thin film is deposited to form a desired pattern, which includes a plurality of processes such as a process of coating a photosensitive solution, an exposing process and a developing process, etc., which, thus, degrades a production yield. 
     In particular, because the masks designed for forming the pattern are quite expensive, as the number of masks used in the processes increases, the fabrication cost of the LCD increases proportionally. 
     A technique for fabricating the array substrate by performing the masking process four times by forming the active pattern and the source and drain electrodes using a single masking process having a slit (diffraction) mask has been proposed. 
     However, because the active pattern, the source and drain electrodes and the data lines are simultaneously patterned by performing an etching process twice with the slit mask, the active pattern protrusively remains near the lower portions of the source electrode, the drain electrode and the data lines. 
     The protrusively remaining active pattern is formed of an intrinsic amorphous silicon thin film, so the protrusively remaining active pattern is exposed to light from the lower backlight, generating an optical current. The amorphous silicon thin film reacts slightly to a blinking of the light from the back light, and repeatedly becomes activated and deactivated, which causes a change in the optical current. The changing optical current component is coupled with a signal flowing in the neighboring pixel electrodes so as to distort movement of the liquid crystal molecules positioned at the pixel electrodes. As a result, a wavy noise is generated such that a wavy fine line appears on a screen of the LCD. 
     In addition, because the active pattern positioned at the lower portion of the data lines has portions that protrude at a certain height from both sides of the data lines, the opening region of the pixel part is encroached by as much as the protrusion height, thus resulting in a reduction in an aperture ratio of the LCD. 
     SUMMARY OF THE INVENTION 
     Accordingly, embodiments of the invention are directed to a liquid crystal display (LCD) and its fabrication method that substantially obviate one or more of the problems due to limitations and disadvantages of the related art. 
     An object of the embodiments of the invention is to provide a transflective liquid crystal display (LCD) and its fabrication method capable of fabricating an array substrate by performing a masking process five times. 
     Another object of the embodiments of the invention is to provide a transflective LCD and its fabrication method capable of implementing high picture quality without generating a wavy noise. 
     Still another object of the embodiments of the invention is to provide a transflective LCD and its fabrication method capable of implementing high luminance by extending an opening region and solving an adhesion problem between a pixel electrode formed of a transparent conductive film and an organic film. 
     Additional features and advantages of embodiments of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of embodiments of the invention. The objectives and other advantages of the embodiments of the invention will be realized and attained by the structure particularly pointed out in the written description and claims thereof as well as the appended drawings. 
     To achieve these and other advantages and in accordance with the purpose of embodiments of the invention, as embodied and broadly described, a transflective liquid crystal display (LCD) includes: a first substrate divided into a pixel part and first and second pad parts; a gate electrode and a gate line formed at the pixel part of the first substrate; a first insulation film formed on the first substrate; an active pattern formed as an island at an upper portion of the gate electrode and having a width smaller than the gate electrode; an ohmic-contact layer and a barrier metal layer formed on the first substrate and on source and drain regions of the active pattern; source and drain electrodes formed at the pixel part of the first substrate and electrically connected with the source and drain regions of the active pattern via the ohmic-contact layer and the barrier metal layer; a data line formed at the pixel part of the first substrate and crossing the gate line to define a pixel region including a reflective portion and a transmissive portion; a pixel electrode formed at the transmissive portion of the pixel region and electrically connected with the drain electrode; a source electrode pattern, a drain electrode pattern and a data line pattern formed at lower portions of the source electrode, the drain electrode and the data line, and formed of a conductive film that forms the pixel electrode; a reflective electrode formed at the reflective portion of the pixel region and electrically connected with the drain electrode and the pixel electrode; a second insulation film exposing the pixel electrode of the pixel region; and a second substrate attached to the first substrate in a facing manner. 
     To achieve these and other advantages and in accordance with the purpose of embodiments of the invention, as embodied and broadly described, a method for fabricating a transflective LCD includes: providing a first substrate divided into a pixel part and first and second pad parts; forming a gate electrode and a gate line at the pixel part of the first substrate; forming a first insulation film on the first substrate; forming an active pattern as an island at an upper portion of the gate electrode and forming an n+ amorphous silicon thin film pattern and a conductive film pattern on the active pattern; forming source and drain electrodes at the pixel part of the first substrate and forming a data line crossing the gate line to define a pixel region including a reflective portion and a transmissive portion; forming a pixel electrode formed of a transparent conductive film at the transmissive portion of the pixel region; forming a second insulation film on the first substrate; forming a reflective electrode formed of an opaque conductive film at the reflective portion of the pixel region; and attaching the first and second substrates. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of embodiments as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention. 
       In the Drawings: 
         FIG. 1  is an exploded perspective view showing a general liquid crystal display (LCD); 
         FIGS. 2A to 2F  are cross-sectional views sequentially showing a fabrication process of an array substrate of a general transflective LCD; 
         FIG. 3  is a plan view showing a portion of an array substrate of a transflective LCD according to the embodiment of the present invention; 
         FIGS. 4A to 4H  are cross-sectional views sequentially showing a fabrication process taken along lines IIIa-IIIa′, IIIb-IIIb and IIIc-IIIc of the array substrate in  FIG. 3 ; 
         FIGS. 5A to 5E  are plan views sequentially showing the fabrication process of the array substrate in  FIG. 3 ; and 
         FIGS. 6A to 6F  are cross-sectional views substantially showing a second masking process in  FIGS. 4B and 5B . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     The transflective liquid crystal display (LCD) and its fabrication method will now be described in detail with reference to the accompanying drawings. 
       FIG. 3  is a plan view showing a portion of an array substrate of the transflective LCD according to the embodiment of the present invention, in which a single pixel including a gate pad part and a data pad part are shown for the sake of explanation. 
     Actually, the N number of gate lines and the M number of data lines are formed to cross each other to define the M×N number of pixels. To simplify the explanation, only a single pixel is shown. 
     As shown, gate lines  116  and the data lines are formed to be arranged vertically and horizontally to define the pixel region on an array substrate  110 . A thin film transistor (TFT), a switching element, is formed at a crossing of the gate line  116  and the data line  117 . A pixel electrode  118   a  and a reflective electrode  118   b  are formed within the pixel region, is connected with the TFT to drive liquid crystal (not shown) together with a common electrode of a color filter substrate (not shown). 
     The pixel region refers to an image display region defined as the gate line  116  and the data line  117  cross, and includes a reflective portion (R) where the reflective electrode  118   b  is formed to implement a reflective mode and a transmissive portion (T) where the pixel electrode  118   a  is formed to implement a transmissive mode. Namely, with the reflective portion (R) and the transmissive portion (T) in the pixel region, light made incident on from the exterior is reflected by the reflective electrode  118   b  in the reflective mode so as to be emitted to the exterior to display an image, and light emitting from a backlight is transmitted through the pixel electrode  118   a  in the transmissive mode to display an image. 
     A gate pad electrode  126   p  and a data pad electrode  127   p  are formed at edge portions of the array substrate  110  and electrically connected with the gate line  116  and the data line  117 , and transfer a scan signal and a data signal applied from an external driving circuit unit (not shown) to the gate line  116  and the data line  117 , respectively. 
     Namely, the gate line  116  and the data line  117  extend to the driving circuit unit so as to be connected with the corresponding gate pad line  116   p  and the data pad line  117   p , and the gate pad line  116   p  and the data pad line  117   p  receive the scan signal and the data signal from a driving circuit unit through the gate pad electrode  126   p  and the data pad electrode  127   p  electrically connected with the gate pad line  116   p  and the data pad line  117   p . Herein, reference numeral  140  denotes a gate pad part contact hole, and the gate pad electrode  126   p  is electrically connected with the gate pad line  117   p  via the gate pad part contact hole  140 . 
     The TFT includes a gate electrode  121  connected with the gate line  116 , a source electrode  122  connected with the data line  117 , and a drain electrode  123  connected with the pixel electrode  118   a  and the reflective electrode  118   b . The TFT also includes an active pattern  124  for forming a conductive channel between the source and drain electrodes  122  and  123  by a gate voltage supplied to the gate electrode  121 . 
     In the embodiment of the present invention, the active pattern  124  is formed of an amorphous silicon thin film, and is formed as an island at an upper portion of the gate electrode  121  to thus reduce an off current of the TFT. 
     At a lower portion of the source electrode  122 , the drain electrode  123  and the data line  117  made of an opaque conductive material, there are formed a source electrode pattern (not shown), a drain electrode pattern (not shown) and a data line pattern (not shown) made of a transparent conductive material and patterned in the same form as the source electrode  122 , the drain electrode  123  and the data line  117 . 
     Although not shown in detail, the reflective electrode  118   b  formed of an opaque conductive film is formed on a second insulation film formed of an organic film and having a bumpy surface. 
     In the embodiment of the present invention, because the pixel electrode  118   a , the source electrode pattern, the drain electrode pattern and the data line pattern formed of a transparent conductive film are formed below the source electrode, the drain electrode  123  and the data line  117 , and the second insulation firm is formed above the source electrode  122 , the drain electrode  123  and the data line  117 , so there is no adhesion problem between the second insulation film and the transparent conductive film. Namely, there is an adhesion problem between the second insulation film formed of the organic film and the transparent conductive film made of ITO or IZO, so plasma processing should be necessarily performed in forming the second insulation film having the bumpy surface. But in the embodiment of the present invention, because the pixel electrode  118   a , the source electrode pattern, the drain electrode pattern and the data line pattern, which are formed of the transparent conductive film, are formed below the source electrode  122 , the drain electrode  123 , and the data line  117 , so the adhesion problem between the second insulation film and the transparent conductive film can be basically avoided. 
     A portion of the source electrode  122  extends in one direction to form a portion of the data line  117 , and a portion of the drain electrode pattern extends to the pixel region to form the pixel electrode  118 . 
     A portion of the previous gate line  116 ′ overlaps with a portion of the pixel electrode  118  with a first insulation film (not shown) interposed therebetween to form a storage capacitor Cst. The storage capacitor Cst serves to uniformly maintain voltage applied to a liquid crystal capacitor until a next signal is received. Namely, the pixel electrode  118  of the array substrate  110  forms the liquid crystal capacitor together with the common electrode of the color filter substrate, and in general, voltage applied to the liquid crystal capacitor is not maintained until the next signal is received but leaked. Thus, in order to uniformly maintain the applied voltage, the storage capacitor Cst should be connected with the liquid crystal capacitor. 
     Besides maintaining the signal, the storage capacitor may also have the effect of stabilizing a gray scale display, reducing flickering effects, reducing the formation of residual images, and the like. 
     In the LCD according to the embodiment of the present invention, the source and drain electrodes  122  and  123 , the pixel electrode  118  and the pad part electrodes  126   p  and  127   p  are patterned and also the pixel region and the pad part form an opening using a single mask such that the array substrate  110  can be fabricated by performing the masking process a total of fifth times using four masks. The fabrication method of the LCD will now be described as follows. 
       FIGS. 4A to 4H  are cross-sectional views sequentially showing a fabrication process taken along lines IIIa-IIIa′, IIIb-IIIb′ and IIIc-IIIc′ of the array substrate in  FIG. 3 . The left side shows the process of fabricating the array substrate of the pixel part and the right side shows the sequential process of fabricating the array substrate of the data pad part and the gate pad part. 
       FIGS. 5A to 5E  are plan views sequentially showing the fabrication process of the array substrate in  FIG. 3 . 
     As shown in  FIGS. 4A and 5A , the gate electrode  121  and gate lines  116  and  116 ′ on the pixel part of the array substrate  110  made of a transparent insulation material such as glass, and the gate pad line  116   p  is formed on the gate pad part of the array substrate  110 . 
     Reference numeral  116 ′ refers to the previous gate line with respect to a corresponding pixel, and the gate line  116  of the corresponding pixel and the previous gate line  116 ′ are formed in the same manner. 
     In this case, the gate electrode  121 , the gate lines  116  and  116 ′ and the gate pad line  116   p  are formed by depositing a first conductive film over the entire surface of the array substrate  110  and selectively patterning it through the photolithography process (the first masking process). 
     Herein, the first conductive film can be made of a low-resistance opaque conductive material such as aluminum (Al), an aluminum alloy, tungsten (W), copper (Cu), chromium (Cr) and molybdenum (Mo), and the like. Also, the first conductive film can be formed with a multi-layered structure by stacking two or more low-resistance conductive materials. 
     Next, as shown in  FIGS. 4B and 5B , a first insulation film  115   a , an amorphous silicon thin film, an n+ amorphous silicon thin film and a second conductive film are formed over the entire surface of the array substrate  110  of the array substrate  110  with the gate electrode  121 , the gate lines  116  and  116 ′ and the gate pad line  116   p  formed thereon, and then selectively removed through the photolithography process (a second masking process) to form an active pattern  124  formed of the amorphous silicon thin film at an upper portion of the gate electrode  121  and at the same time to form a gate pad part contact hole  140  exposing a portion of the gate pad line  116   p.    
     An n+ amorphous silicon thin film pattern  125 ′ and a conductive film pattern  130 ′, which are formed of the n+ amorphous silicon thin film and the second conductive film and have the same pattern as the active pattern  124 , remain on the active pattern  124 . 
     In the embodiment of the present invention, the gate pad part contact hole  140  is formed long in a direction substantially parallel to the gate pad line  116   p . However, the present invention can be applicable regardless of the configuration of the gate pad part contact hole  140 . 
     Herein, in the embodiment of the present invention, the active pattern  124  is formed as an island over the gate electrode  121  and within the boundaries defined by the perimeter of the gate electrode  121  with the first insulation film  115   a  interposed therebetween, and the active pattern  124  and the gate pad part contact hole  140  are formed using a single mask, such as a half-tone mask or a diffraction (slit) mask (hereinafter, it is assumed that referring to the half-tone mask means it also includes the diffraction mask). The second masking process will now be described in detail as follows. 
       FIGS. 6A to 6F  are cross-sectional views showing a second masking process in detail in  FIGS. 4B and 5B . 
     As shown in  FIG. 6A , the first insulation film  115   a , the amorphous silicon thin film  120 , the n+ amorphous silicon thin film  125  and the second conductive film  130  are formed over the entire surface of the array substrate  110  with the gate electrode  121 , the gate lines  116  and  116 ′ and the gate pad line  116   p  formed thereon. 
     In this case, the second conductive film  130  is used as a barrier metal layer that reduces contact resistance between an ohmic-contact layer formed on the n+ amorphous silicon thin film and source/drain electrode patterns formed of a transparent conductive film (to be described), and can be formed with a thickness of about 50 Å-100 Å by using a conductive material such as molybdenum. 
     Thereafter, as shown in  FIG. 6B , a first photosensitive film  170  made of a photosensitive material such as photoresist is formed over the entire surface of the array substrate  110 , on which light is selectively irradiated through the half-tone mask  180 . 
     The half-tone mask  180  used in the embodiment of the present invention includes a first transmission region (I) that allows irradiated light to be entirely transmitted therethrough, a second transmission region (II) that allows only light to be partially transmitted therethrough while blocking the remaining light, and a blocking region (III) that entirely blocks the irradiated light. Only light which has transmitted through the half-tone mask  180  can be irradiated onto the first photosensitive film  170 . 
     Subsequently, when the first photosensitive film  170  which has been exposed through the half-tone mask  180  is developed, as shown in  FIG. 6C , first and second photosensitive film patterns  170   a  and  170   b  remain at regions where light has been entirely blocked or partially blocked through the blocking region (III) and the second transmission region (II), and the first photosensitive film at the transmission region (I) through which light had been entirely transmitted has been completely removed to expose the surface of the second conductive film  130 . 
     At this time, the first photosensitive film pattern  170   a  formed at the blocking region III is thicker than the second photosensitive film pattern  170   b  formed through the second transmission region II. In addition, the photosensitive film at the region where the light had entirely transmitted through the first transmission region I has been completely removed. This is because positive photoresist has been used. However, negative photoresist can be also used in the embodiments of the present invention. 
     Thereafter, as shown in  FIG. 6D , the first insulation film  115   a , the amorphous silicon thin film  120 , the n+ amorphous silicon thin film  125  and the second conductive film  130  are selectively removed by using the first and second photosensitive film patterns  170   a  and  170   b  as masks to form the gate pad part contact hole  140  exposing a portion of the gate pad line  116   p  at the gate pad part of the array substrate  110 . 
     Then, an ashing process is performed to remove a portion of the first photosensitive film pattern  170   a  and the entirety of the second photosensitive film pattern  170   b . Then, as shown in  FIG. 6E , the second photosensitive film pattern of the second transmission region II is completely removed. 
     In this case, the first photosensitive film pattern remains as a third photosensitive film pattern  170 ′ by removing the thickness of the second photosensitive film pattern only at the active pattern region corresponding to the blocking region III. 
     Thereafter, as shown in  FIG. 6F , portions of the amorphous silicon thin film, the n+ amorphous silicon thin film and the second conductive film are removed by using the remaining third photosensitive film pattern  170 ′ as a mask to form the active pattern  124  as an island over the gate electrode  121  and within boundaries defined by the perimeter of the gate electrode  121  to thus reduce an off current of the TFT. 
     At this time, the n+ amorphous silicon thin film pattern  125 ′ and the conductive film pattern  130 ′, which are formed of the n+ amorphous silicon thin film and the second conductive film and have been patterned in the same form as the active pattern  124 , remain at the upper portion of the active pattern  124 . 
     In the embodiment of the present invention, the active pattern  124  is formed as an island over the gate electrode  121  and within boundaries defined by the perimeter of the gate electrode  121  to thus reduce an off current of the TFT. 
     Next, as shown in  FIGS. 4C and 4D , third and fourth conductive films  150  and  160  are deposited over the entire surface of the array substrate  110  with the active pattern  124  formed thereon. 
     A second photosensitive film  270 , which has been patterned to have a certain form, is formed on the array substrate  110  (a third masking process). 
     Thereafter, as shown in  FIGS. 4E and 5C , portions of the third and fourth conductive films  150  and  160  are removed by using the second photosensitive film  270  as a mask to form the pixel electrode  118  formed of the third conductive film and at the same time to form the source electrode  122 , the drain electrode  123  and the data line  117  formed of the fourth conductive film at the pixel part of the array substrate  110 . 
     In addition, through the third masking process, the data pad electrode  127   p  and the gate pad electrode  126   p , which are formed of the third conductive film, are formed at the data pad part and the gate pad part of the array substrate  110 . 
     In this case, on the lower part of the source electrode  122 , the drain electrode  123  and the data line  117 , there are formed a source electrode pattern  122 ′, a drain electrode pattern  123 ′ and a data line pattern (not shown) are formed from the third conductive film and patterned according to the shape of the source electrode  122 , the drain electrode  123  and the data line  117 . 
     In addition, a pixel electrode pattern  160 ′, a data pad electrode pattern  160 ″ and a gate pad electrode pattern  160 ′″ formed of a fourth conductive film and patterned according to the shape of the pixel electrode  118 , the data pad electrode  127   p  and the gate pad electrode  126   p  remain at the upper portions of the pixel electrode  118 , the data pad electrode  127   p  and the gate pad electrode  126   p.    
     A certain region of the n+ amorphous silicon thin film pattern  125 ′ formed on the active pattern  124  is removed through the third masking process to form an ohmic-contact layer  125 ″ that allows the active pattern  124  and the source and drain electrodes  122  and  123  to ohmic-contact with each other, and a barrier metal layer  130 ″ made of the second conductive film and patterned in the same form as the ohmic-contact layer  125 ″ is formed at the upper portion of the ohmic-contact layer  125 ″. 
     In this case, the gate pad electrode  126   p  is electrically connected with the lower gate pad line  116   p  via the gate pad part contact hole  140 , and the pixel electrode  118  is connected with the drain electrode pattern  123 ′ so as to be electrically connected with the drain electrode  123 . 
     Herein, the third conductive film is made of a transparent conductive material with good transmittance such as indium-tin-oxide (ITO) or indium-zinc-oxide (IZO) to form the pixel electrode  118 , the data pad electrode  127   p  and the gate pad electrode  126   p . The fourth conductive film can be made of low-resistance opaque conductive material such as aluminum (Al), an aluminum alloy, tungsten (W), copper (Cu), chromium (Cr) and molybdenum (Mo), or the like to form the source electrode  122 , the drain electrode  123  and the data line. 
     In the embodiment of the present invention, a tail of the active pattern formed of the amorphous silicon thin film does not exist at the lower portion of the data line  117 , so there is no signal interference of the data line  117  possible by the tail and an aperture ratio increases by the width of the tail of the active pattern. In addition, because there is no tail of the active pattern, no wavy noise is generated, and thus, the LCD can have high picture quality. For reference, as mentioned above, the tail of active pattern is formed at the lower portion of the data line during the process of forming the active pattern, the source and drain electrodes and the data line by using the slit mask through the single making process, and because it has width wider than that of the data line, it causes the signal interference of the data line and degradation of an aperture ratio. 
     As shown in  FIGS. 4F ,  4 G and  5 D, the second insulation film  115   b  and a third photosensitive film  370 , which has been patterned to have a certain form, are formed over the entire surface of the array substrate  110  and then the second insulation film  115   b  is selectively removed by using the photolithography process (a fourth masking process) to open the pixel region and the pad part. In this case, the second insulation film  115   b  may be formed of an organic film such as photoacryl to have a bumpy surface at the reflective portion. The bumpy surface serves to increase reflectivity of the reflective portion. 
     In this case, as mentioned above, because the pixel electrode  118   a , the source electrode pattern  122 ′, the drain electrode pattern  123 ′, and the data line pattern  117 ′, which are formed of the transparent conductive film, are formed underneath the source electrode  122 , the drain electrode  123 , and the data line  117 , and the second insulation film  115   b  is formed on the source electrode  122  and the drain electrode  123 , so the adhesion problem can be avoided between the second insulation film  115   b  and the transparent conductive films (namely, the pixel electrode  118   a , the source electrode pattern  122 ′, the drain electrode pattern  123 ′, and the data line pattern  117 ′). 
     The pixel electrode pattern  160 ′, the data pad electrode pattern  160 ″ and the gate pad electrode pattern  160 ′″ are removed by using the fourth masking process to expose the pixel electrode  118 , the data pad electrode  127   p  and the gate pad electrode  126   p . A portion of the corresponding pixel electrode  118  overlaps with a portion of the previous gate line  116 ′ to form a storage capacitor Cst together with the previous gate line  116 ′ with the first insulation film  115   a  interposed therebetween. 
     Thereafter, as shown in  FIGS. 4H and 5E , a fifth conductive film is formed over the entire surface of the array substrate  110  and selectively removed by using the photolithography process (a fifth masking process) to form the reflective electrode  118   b  at the reflective portion. 
     The fifth conductive film may be made of a conductive material with good reflectivity such as aluminum to form the reflective electrode  118   b.    
     The array substrate according to the embodiment of the present invention is attached with color filter substrates in a facing manner by a sealant applied to outer edges of the image display part. In this case, the color filter substrates include black matrixes for preventing leakage of light to the TFTs, the gate lines and the data lines and color filters for implementing red, green and blue colors. 
     The attachment of the color filter substrates and the array substrates are made through attachment keys formed on the color filter substrates or the array substrates. 
     In the embodiment of the present invention, as the active patterns, the amorphous silicon TFT using the amorphous silicon thin film is used as an example, but the present invention is not limited thereto and as the active patterns, polycrystalline silicon TFTs using a polycrystalline silicon thin film can be also used. 
     The present invention can be also applied to a different display device fabricated by using TFTs, for example, an OLED (Organic Light Emitting Diode) display device in which OLEDs are connected with driving transistors. 
     As the present invention may be embodied in several forms without departing from the spirit or essential characteristics thereof, it should also be understood that the above-described embodiments are not limited by any of the details of the foregoing description, unless otherwise specified, but rather should be construed broadly within its spirit and scope as defined in the appended claims, and therefore all changes and modifications that fall within the metes and bounds of the claims, or equivalents of such metes and bounds are therefore intended to be embraced by the appended claims.