Liquid crystal display device and fabricating method thereof

A liquid crystal display device includes a first substrate, a second substrate and a liquid crystal layer between the first and second substrates. The liquid crystal display device further includes a gate line on the first substrate, a first insulation film on the gate line, a data line crossing the gate line such that the data line and the gate line define a pixel region with a transmission area and a reflection area, a thin film transistor connected to the gate line and the data line, a storage capacitor including a storage line crossing the data line and an upper storage electrode connected to the thin film transistor, a second insulation film on the thin film transistor with a transmission hole defined through the second insulation film, a reflection electrode disposed on the second insulation film in the reflection area and connected to a portion of the upper storage electrode through the transmission hole, and a pixel electrode disposed in the pixel region and connected to the reflection electrode.

This application claims the benefit of the Korean Patent Application No. P2004-41136 filed on Jun. 5, 2004, which is hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a liquid crystal display device, and more particularly, to a transflective thin film transistor substrate and method of fabricating the same.

2. Description of the Related Art

Liquid crystal display devices are generally classified into a transmissive type where a picture is displayed using light incident from a backlight unit, and a reflective type where a picture is displayed by reflecting external light such as a natural light. However, the power consumption of the backlight unit is high in the transmissive type, and the reflective type depends on the external light so that it cannot display a picture in a dark environment.

To resolve this problem, a transflective liquid crystal display device is increasingly being used, wherein the transflective liquid crystal can be selected to be in a transmissive mode where the backlight unit is used or in a reflective mode where the external light is used. The transflective liquid crystal display device operates in the reflective mode if the external light is sufficient and in the transmissive mode if the external light is not sufficient, thereby reducing the power consumption more than the transmissive liquid crystal display device but not being restricted by external light levels unlike the reflective liquid crystal display device.

Generally, a transflective liquid crystal display panel of the related art, as shown inFIG. 1, includes a color filter substrate and a thin film transistor substrate which are bonded together with a liquid crystal layer (not shown), and a backlight unit60arranged behind the thin film transistor substrate. Each pixel of the transflective liquid crystal display panel is divided into a reflective area where a reflective electrode28is formed, and a transmissive area where the reflective electrode28is not formed.

The color filter substrate includes an upper substrate52, a black matrix (not shown), a color filter54formed on the upper substrate52, a common electrode56, and an alignment film (not shown) formed thereover. The thin film transistor substrate includes a lower substrate2, a gate line4, a data line (not shown) formed on the lower substrate2crossing the gate line4to define each pixel area, a thin film transistor connected to the gate line4and the data line, a pixel electrode32formed at the pixel area and connected to the thin film transistor; and a reflection electrode28formed at a reflection area of each pixel to overlap the pixel electrode.

The thin film transistor includes a gate electrode6connected to the gate line4; a source electrode16connected to the data line; a drain electrode18facing the source electrode16; an active layer10overlapping the gate electrode6with a gate insulating film8therebetween to form a channel between the source and drain electrodes16and18; and an ohmic contact layer12to make an ohmic contact with the active layer10, the source electrode16, and the drain electrode18. The thin film transistor responds to the scan signal of the gate line4, thereby causing a video signal on the data line to be charged and maintained on the pixel electrode32.

The reflection electrode28reflects an external light that is incident through a color filter substrate toward the color filter substrate. At this moment, the surface of an organic film24formed under the reflection electrode28has an embossing shape, and the reflection electrode28on top of the organic film24also has the embossing shape, thereby increasing its reflection efficiency due to its dispersion effect.

The pixel electrode32is connected via an upper storage electrode20to the drain electrode of the thin film transistor, and the pixel electrode32generates a potential difference with a common electrode56by the pixel signal supplied through the thin film transistor. The potential difference causes liquid crystal molecules having dielectric anisotropy to rotate, thereby controlling the transmissivity of the light that passes through a liquid crystal layer of each of the reflection area and a transmission area, and changing its brightness in accordance with the video signal.

In this case, a transmission hole36is formed in the relatively thick organic film24at a transmission area so that the length of the light path going through the liquid crystal layer is the same in the reflection area as in the transmission area. As a result, a path that ambient light incident at the reflection area, i.e., a reflection light RL, goes through the liquid crystal layer, then through the reflection electrode28, and then through the liquid crystal layer in the liquid crystal layer is the same in length as a path that the transmission light TL of a backlight unit60, which is incident at the transmission area going through the liquid crystal layer. Thus, the transmission efficiency becomes the same in both of the reflection mode and the transmission mode.

The thin film transistor substrate further includes a storage capacitor connected to the pixel electrode32to maintain the video signal supplied to the pixel electrode32stable. The storage capacitor is formed with an upper storage electrode20overlapping a storage line40with a gate insulating film8therebetween. Here, wherein the upper storage electrode20is extended from the drain electrode18to connect to the pixel electrode32via a contact hole34. The ohmic contact layer12and the active layer10further overlap under the upper storage electrode20in the process.

The thin film transistor substrate further includes a first passivation film22between the thin film transistor and the organic film24; a second passivation film26between the organic film24and the reflection electrode28; and a third passivation film30between the reflection electrode28and the pixel electrode32. Accordingly, the contact hole34penetrates the first to the third passivation films22,26and30, the organic film24and the reflection electrode28so that the pixel electrode32is connected to the upper storage electrode20.

In such a transflective liquid crystal display panel, the thin film transistor substrate includes the semiconductor process and requires a plurality of mask processes. Thus, its manufacturing process is complicated so that it significantly increases the liquid crystal display panel manufacturing cost.

Hereinafter, a fabricating method of the transflective thin film transistor substrate according to the related art will be described in reference withFIGS. 2A to 2F. As shown inFIG. 2A, in a first mask process, a gate pattern including the gate line4, the gate electrode6, and the storage line40is formed on the lower substrate2.

A gate metal layer is formed on the lower substrate2by a deposition method such as sputtering. Subsequently, the gate metal layer is patterned by a photolithography process using a first mask and an etching process, thereby forming the gate pattern including the gate line4, the gate electrode6, and the storage line40. The gate metal layer is a single layered or double layered metal, such as Al, Mo, or Cr.

As shown inFIG. 2B, the gate insulating film8is formed on the substrate2having the gate pattern. On the substrate2having the gate insulating film8, a semiconductor pattern having the active layer10and the ohmic contact layer12formed, and a source/drain pattern having the data line, the source electrode16, the drain electrode18and the upper storage electrode20are stacked by the second mask process.

The gate insulating film8, an amorphous silicon layer, an amorphous silicon layer with impurities doped thereto, and the source/drain metal layer are sequentially formed on the lower substrate2where the gate pattern is formed. The gate insulating film8is formed of an inorganic insulating material such as silicon oxide SiOx or silicon nitride SiNx, and the source/drain metal layer is the single layered or double layered structure of the metal such as Al, Mo or the like.

A photoresist pattern is formed on top of the source/drain metal layer by a photolithography process using a second mask. In this case, a diffractive exposure mask having a diffractive exposure portion at a channel of the thin film transistor is used as the second mask. Thus, the photoresist pattern of the channel has a lower height than the source/drain pattern portion. Subsequently, the source/drain metal layer is patterned by a wet etching process using the photoresist pattern to form the source/drain pattern that includes the data line, the source electrode16, the drain electrode18integrated with the source electrode16, and the storage electrode20. Then, the amorphous silicon layer doped with the impurities and the amorphous silicon layer are simultaneously patterned by a dry etching process using the same photoresist pattern, thereby forming the ohmic contact layer12and the active layer10. After removing the photoresist pattern having relatively low height at the channel by an ashing process, the source/drain pattern and the ohmic contact layer12of the channel are etched by a dry etching process. Accordingly, the active layer10of the channel is exposed to separate the source electrode16from the drain electrode18. Subsequently, the photoresist pattern remaining on the source/drain pattern is removed by a stripping process.

As shown inFIG. 2C, a first passivation film22is formed on the gate insulating film8where the source/drain pattern is formed, and an organic film24is formed on top thereof by a third mask process. Here, the organic film24has a contact hole34and a transmission hole36with the embossing shaped surface.

The first passivation film22and the organic film24are sequentially formed on the gate insulating film8where the source/drain pattern is formed. The first passivation film22is formed of the same inorganic insulating material as the gate insulating film8, and the organic film24is of a photosensitive organic material, such as an acrylic resin.

Then, the organic film24is patterned by a photolithography process using the third mask, thereby forming an open hole35and the transmission hole36which penetrate the organic film24in correspondence to the transmission portion of the third mask. At this moment, the third mask has a structure where a shielding portion and a diffractive exposure portion repeat at the rest area except for the transmission portion. The organic film24remaining in correspondence thereto is patterned to have a structure that a shielding area (projected portion) and a diffractive exposure area (groove portion) having a stepped difference are repeated. Subsequently, the organic film24where the projected portion and the groove portion are repeated is fired so that the surface of the organic film24has the embossing shape.

As shown inFIG. 2D, a second passivation film26is formed on the organic film24that has the embossing shape, and the reflection electrode28is formed on top thereof by a fourth mask process. The second passivation film26and the reflective metal layer are deposited to maintain their embossing shape on top of the organic film24that has the embossing surface. The second passivation film26is formed of an inorganic insulating material such as the first passivation film22, and the reflective metal layer is formed of a metal such as AlNd or the like, of which the reflectivity is high. Subsequently, the reflective metal layer is patterned by a photolithography process using a fourth mask and the etching process to form the reflection electrode28. Here, the reflection electrode is independent of every pixel and is opened at the transmission hole36and the open hole35of the organic film24.

As shown inFIG. 2E, a third passivation film30covering the reflection electrode28is formed by a fifth mask process, and the contact hole34penetrating the first to third passivation films22,26,30is formed. The third passivation film30covering the reflection electrode28is formed and the contact hole34is formed by a photolithography process using a fifth mask and the etching process. Here, the contact hole34penetrates the first to third passivation films22,26,30at the open hole35of the organic film24. The contact hole34exposes the drain electrode18and the upper storage electrode20. The third passivation film30is formed of the same inorganic insulating material as the second passivation film26.

As shown inFIG. 2F, a pixel electrode32is formed on the third passivation film30using a sixth mask process. A transparent conductive layer is formed on the third passivation film30by the deposition method such as sputtering, and the transparent conductive layer is patterned by a photolithography process using a sixth mask and the etching process to form the pixel electrode32at each pixel area. The pixel electrode32is connected to the upper storage electrode20through the contact hole34. The transparent conductive layer is formed of indium-tin-oxide ITO.

In this way, the related art transflective thin film transistor substrate is formed by six mask processes, thereby complicating its manufacturing process is complicated.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to a liquid crystal display device and fabricating method thereof that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.

An object of the present invention to provide a transflective thin film transistor substrate and a method of fabricating the same with a simplified process.

To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, a liquid crystal display device comprises a first substrate a gate line on the first substrate; a first insulation film on the gate line; a data line crossing the gate line such that the data line and the gate line define a pixel region with a transmission area and a reflection area; a thin film transistor connected to the gate line and the data line; a storage capacitor including a storage line crossing the data line, and an upper storage electrode being connected to the thin film transistor and overlapping the storage line; a second insulation film on the thin film transistor, a transmission hole being defined through the second insulation film; a reflection electrode disposed on the second insulation film in the reflection area and connected to a portion of the upper storage electrode through the transmission hole; a pixel electrode disposed in the pixel region and connected to the reflection electrode; a second substrate facing the first substrate; and a liquid crystal layer disposed between the first and second substrates.

In another aspect, a method of fabricating a liquid crystal display device comprises forming a gate pattern on a first substrate using a first mask, the gate pattern including a gate line, a gate electrode connected to the gate line, and a storage line; forming a first insulation film on the gate pattern, a semiconductor pattern on the first insulation film, and a source/drain pattern having a data line, a source electrode, a drain electrode, and an upper storage electrode using a second mask, the data and gate lines crossing each other to define a pixel region with a transmission area and a reflection area; forming a second insulation film on the source/drain pattern using a third mask, the second insulation film defining a transmission hole through the second insulation film; forming a reflection electrode in the reflection area using a fourth mask, the reflection electrode being connected to a portion of the upper storage electrode through the transmission hole; forming a third insulation film on the reflection electrode and a pixel electrode using a fifth mask, the pixel electrode being connected to the reflection electrode; and joining the first substrate with a second substrate and disposing a liquid crystal layer between the first and second substrates.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, the preferred embodiment of the present invention will be described in detail with reference toFIGS. 3 to 11D.

FIG. 3is a plane view partially illustrating a transflective thin film transistor substrate according to an embodiment of the present invention, andFIG. 4is a sectional view illustrating the transflective thin film transistor substrate taken along lines II-II′, III-III, IV-IV′ ofFIG. 3.

As shown inFIGS. 3 and 4, the transflective thin film transistor substrate includes a lower substrate142; a gate line102and a data line104that define a pixel area on the lower substrate142crossing each other with a gate insulating film144therebetween; a thin film transistor106connected to the gate line102and the data line104; a reflection electrode152formed at a reflection area of each pixel; and a pixel electrode118formed at each pixel area and connected to the thin film transistor106through the reflection electrode152and an upper storage electrode122. The transflective thin film transistor substrate includes a storage capacitor120formed by overlapping a storage line150with the upper storage electrode122connected to the pixel electrode118via the reflection electrode152; a gate pad124connected to the gate line102; and a data pad134connected to the data line104. The transflective thin film transistor substrate divides each pixel area into a reflection area where the reflection electrode152is formed and a transmission area where the reflection electrode152is not formed.

The thin film transistor106includes a gate electrode108connected to the gate line102; a source electrode110connected to the data line104; a drain electrode112facing the source electrode110to be connected to the pixel electrode118; an active layer114overlapping the gate electrode108with a gate insulating film144therebetween to form a channel between the source electrode110and the drain electrodes112; and an ohmic contact layer116formed on the active layer114except for a channel portion to make an ohmic contact with the source electrode110and the drain electrode112. The thin film transistor106responds to the scan signal of the gate line102to cause a video signal on the data line104to be charged and maintained in the pixel electrode118. A semiconductor pattern115including the active layer114and the ohmic contact layer116is formed to overlap the data line104as well.

The reflection electrode152is formed at the reflection area of each pixel to reflect an external light. The reflection electrode152has the embossing shape in accordance with the shape of the organic film148, thereby increasing its reflection efficiency due to its dispersion effect. Further, the reflection electrode152is connected via a transmission hole150penetrating the organic film148to a side surface of the upper storage electrode122.

The transmission hole154is formed at the transmission area to penetrate a gate insulating film144, the organic film148, the reflection electrode152, and the passivation film146. Accordingly, the length of the light path that runs through the liquid crystal layer becomes the same at the reflection area and the transmission area. Thus, the transmission efficiency of the reflection mode and the transmission mode becomes the same. As the transmission hole goes from the gate insulating film144to the passivation film146, its width becomes wider. Accordingly, the reflection electrode152formed at a reflection area is practically exposed.

The pixel electrode118independently formed at each pixel area overlapping with a partial portion of the reflection electrode152exposed through the transmission hole154and is connected. Accordingly, the pixel electrode118is connected to the reflection electrode152of the pixel electrode118, and to the drain electrode112of the thin film transistor106via the upper storage electrode122connected to the reflection electrode152. The pixel electrode118generates a potential difference with a common electrode of a color filter (not shown) by a pixel signal supplied through the thin film transistor. The potential difference causes liquid crystal molecules having dielectric anisotropy to rotate, thereby controlling the transmissivity of the light that runs through a liquid crystal layer in each of the reflection area and the transmission area. Thus, its brightness is changed in accordance with the video signal. Herein, an opening portion of the passivation film146overlaps with a partial transmission hole154and a partial reflection electrode152adjacent to the transmission hole154. Further, the passivation film146forms a boundary from the pixel electrode118.

The storage line150adjacent to the gate line102and crossing the data line104overlaps the upper storage electrode122connected to the pixel electrode118with the gate insulating film144therebetween, thereby forming the storage capacitor120. The upper storage electrode122is integrated with the drain electrode112, and is connected to the pixel electrode118through the reflection electrode152. The upper storage electrode112further overlaps the semiconductor pattern115under the upper storage electrode122.

The gate line102is connected to a gate driver (not shown) through the gate pad124. The gate pad124includes a lower gate pad electrode128extended from the gate line102; and an upper gate pad electrode130connected to the lower gate pad electrode128via a contact hole126penetrating through the passivation film146and the gate insulating film144.

The data line104is connected to a data driver (not shown) through the data pad134. The data pad134includes a lower data pad electrode138extended from the data line104; and an upper data pad electrode130connected to a side surface of the lower data pad elelctrode138via a second contact hole136penetrating the passivation film146, the lower data pad electrode138, and the semiconductor pattern115.

In the transflective thin film transistor substrate having the above structure, a transparent conductive pattern including the pixel electrode118, the upper gate pad electrode130, and the upper data pad electrode140is formed by the same patterning process of the transparent conductive layer. In this case, the transparent conductive layer is patterned by the lift-off process removing the photoresist pattern used in forming the transmission hole154, the first hole126, and the second contact hole136. The transmission hole154, the first hole126, and the second contact hole136penetrate from passivation film146to the gate insulating film144in the previous process. Accordingly, the transparent conductive pattern forms a boundary from an edge portion of the passivation film146.

As a result, the transflective thin film transistor substrate according to the embodiment of the present invention is formed by the following five mask processes.FIGS. 5A and 5Bare a plane view and a sectional view explaining a first mask process in a fabricating method of the transflective thin film transistor substrate according to the embodiment of the present invention.

A gate pattern is formed by a first mask process where the gate pattern includes the gate line102, the gate electrode108connected to the gate line102, the lower gate pad electrode128, and the storage line150on the lower substrate142. More particularly, the gate metal layer is formed on the lower substrate by a deposition method such as sputtering. The gate metal layer is patterned by a photolithography process using a first mask and an etching process, thereby forming the gate pattern that includes the gate line102, the gate electrode108, the lower gate pad electrode128, and the storage line150. The gate metal layer is formed of a metal material such as Mo, Cu, Al(Nd), Cr, Ti, MoW, Ta or the like. Further, the gate metal layer can be formed with a double layer having a first conductive layer and a second conductive layer, wherein the first conductive layer is formed of ITO, TO, IZO or the like and the second conductive layer is formed of a metal material as mentioned above.

FIGS. 6A and 6Bare a plane view and a sectional view explaining a second mask process in a fabricating method of the transflective thin film transistor substrate according to the present invention.FIGS. 7A to 7Eare sectional views specifically explaining the second mask process.

The gate insulating film144is formed on the lower substrate142where the gate pattern is formed. A source/drain pattern including the data line104, the source electrode110, the drain electrode112, the upper storage electrode122and the lower data pad electrode138, a semiconductor pattern115including the active layer114and the ohmic contact layer116that overlap along the rear surface of the source/drain pattern are formed on top thereof by a second mask process. The semiconductor pattern115and the source/drain pattern are formed by a one mask process using a diffractive exposure mask.

Specifically, the gate insulating film144, an amorphous silicon layer105, an amorphous silicon layer107doped with impurities n+ or p+, a source/drain metal layer109are sequentially formed on the lower substrate142where the gate pattern is formed as inFIG. 7A. For example, the gate insulating film144, the amorphous silicon layer105, the amorphous silicon layer107doped with impurities are formed by PECVD, and the source/drain metal layer109is formed by sputtering. The gate insulating film144is formed of inorganic insulating material such as silicon oxide SiOx, silicon nitride SiNx and like. The source/drain metal layer109is formed of metal material such as Mo, Cu, Al(Nd), Cr, Ti, MoW, Ta or the like.

A photoresist219is spread over the source/drain metal layer109, and then the photoresist219is exposed and developed by a photolithography process using a diffractive exposure mask210, thereby forming a photoresist pattern220having the stepped difference as shown inFIG. 7B. The diffractive exposure mask210includes a transparent quartz substrate212, a shielding layer214on top of the substrate212formed of a metal layer such as Cr and CrOx and the like, and a diffractive exposure slit216. The shielding layer214is located at an area where the semiconductor pattern and the source/drain pattern are to be formed to intercept ultraviolet ray, thereby leaving a first photoresist pattern220A after development. The diffractive exposure slit216is located at an area where the channel of the thin film transistor is to be formed to diffract the ultraviolet ray, thereby remaining a second photoresist pattern220B that is thinner than the first photoresist pattern220A after development.

Subsequently, the source/drain metal layer109is patterned by the etching process using the photoresist pattern220having a stepped difference, thereby forming the source/drain pattern and the semiconductor pattern115thereunder as shown inFIG. 7C. In this case, the source electrode110and the drain electrode112in the source/drain pattern have a structure where they are integrated.

Then, the photoresist pattern220is ashed by an ashing process using an oxygen O2plasma. Thus, the first photoresist pattern220A becomes thinner and the second photoresist pattern220B is removed as shown inFIG. 7D. The source/drain pattern exposed by the removal of the second photoresist pattern220B and the ohmic contact layer116thereunder are eliminated by the etching process using the ashed first photoresist pattern220A, thereby separating the source electrode110from the drain electrode112and exposing the active layer114. Accordingly, a channel of the active layer114is formed between the source electrode110and the drain electrode112. At this moment, both sides of the source/drain pattern are etched once more along the ashed first photoresist pattern220A, thus the source/drain pattern and the semiconductor pattern115have a fixed stepped difference in a step shape.

Then, the first photoresist pattern220A remaining on the source/drain pattern is removed by a strip process as inFIG. 7E.

FIGS. 8A and 8Bare a plane view and a sectional view explaining a third mask process in a fabricating method of the transflective thin film transistor substrate according to the present invention.

On the gate insulating film144having the source/drain pattern formed by the third mask process, the transmission hole154is formed at the transmission area and the organic film148(having an embossing surface at the reflection area) removed at the pad area is formed. Specifically, the organic film148is formed on the gate insulating film144having the source/drain pattern by spin coating. The organic film148is formed of a photosensitive organic material such as acrylic resin. Then, the organic film148is patterned by the photolithography process using the third mask, that is, a half tone mask or a diffractive exposure mask. Thus the transmission hole155penetrating the organic film148is formed in the transmission area in correspondence to the transmission portion of the third mask, and the organic film148is removed at the pad area. Further, the remaining portion except for the transmission portion in the third mask has a structure that the shielding portion and the diffractive exposure portion (or transflective portion) are repeated. In correspondence thereto, the organic film148is patterned to have a structure where the shielding area (projected portion) and the diffractive exposure area (groove portion) having the stepped difference are repeated in the reflection area. Subsequently, the organic film148with the repeated projected portion and groove portion is cured to form the embossing shape on the surface of the organic film148.

FIGS. 9A and 9Bare a plane view and a sectional view explaining a fourth mask process in a fabricating method of the transflective thin film transistor substrate according to the present invention.

The reflection electrode152is formed at each pixel reflection area by the fourth mask process. Specifically, a reflective metal layer having an embossing surface is formed on the organic film148and maintains the embossing shape. The reflective metal layer is formed of a metal that has a high reflectivity like AlNd. Subsequently, the reflective metal layer is patterned by a photolithography process using the fourth mask and the etching process, thereby independently forming the reflection electrode152at every reflection area of each pixel. The reflection electrode152is connected to the drain electrode112via a side surface of the upper storage electrode122exposed at the edge portion of the transmission hole154.

FIGS. 10A and 10Bare a plane view and a sectional view explaining a fifth mask process in a fabricating method of the transflective thin film transistor substrate according to of the present invention,FIGS. 11A and 11Dare sectional views to specifically describe the fifth mask process of the present invention.

In the fifth mask process, the transmission hole154penetrates from the passivation film146through the gate insulating film144; the first and the second contact holes126and136exposing the lower gate pad electrode128and the lower data pad electrode138are formed; and a transparent conductive pattern including the pixel electrode118, the upper gate pad electrode130and the upper data pad electrode140is formed.

Specifically, as shown inFIG. 11A, the passivation film146covering the reflection electrode152is formed by the deposition method such as PECVD. A photoresist pattern230is formed on the passivation film146by a photolithography process. The passivation film146is of an inorganic insulating material like that used for the gate insulating film144. The photoresist pattern230has an opened structure at the area having the transmission hole154, the lower gate pad electrode128and the lower data pad electrode138.

The passivation film146and the gate insulating film144are patterned by the etching process using the above photoresist pattern230so that the transmission hole154penetrates the passivation film150and the gate insulating film144as shown inFIG. 11B, and the first and the second contact holes126and136exposing the lower gate pad electrode128and the lower data pad electrode138are formed. The transmission hole154exposes a partial reflection electrode152. The first contact hole126penetrates the passivation film146and the gate insulating film144to expose the lower gate pad electrode128. The second contact hole136penetrates the passivation film146, the lower data pad electrode138and the semiconductor pattern115to expose a side surface of the lower data pad electrode138. In this case, the edge part of the photoresist pattern230has more projected shape than the edge part of the passivation film146due to the over-etched passivation film146. The ashing process and the etching process are continually performed in the same chamber.

Subsequently, a transparent conductive film117is entirely on the thin film transistor substrate having the photoresist pattern230by a deposition method such as sputtering. The transparent conductive film117is formed of ITO, TO, IZO or the like. At this time, the transparent conductive film117deposited having a straight property by the edge portion of the projected photoresist pattern230is opened at the edge portion of the passivation film146to form a stripper osmosis path.

The photoresist pattern230and the transparent conductive film117on the photoresist pattern230are removed together by the lift-off process, thereby forming the transparent conductive pattern including the pixel electrode118, the upper gate pad electrode132and the upper data pad electrode140, as shown inFIG. 11D. At this time, because the stripper is easily passed into the edge part of the passivation film146via the osmosis path formed by open of the transparent conductive film117, lift-off efficiency can be improved. The pixel electrode118forms a boundary from the passivation film146in the transmission hole154. The pixel electrode118is connected to the exposed reflection electrode152. The upper gate pad electrode130forms a boundary from the passivation film146in the first contact hole126to connected to the lower gate pad electrode128. The upper data pad electrode140forms a boundary from the passivation film146in the second contact hole136to connected to a side surface of the lower data pad electrode138.

As described above, in the transflective thin film transistor substrate and the method of driving the same, the transparent conductive pattern is formed by the lift-off process of the photoresist pattern used in forming the transmission hole and the contact hole that penetrate the passivation film and the gate insulating film, thereby simplifying the processes by performing a five mask process.