Abstract:
Disclosed is a method of manufacturing an organic light-emitting display device capable of improving efficiency of a laser generator used for crystallization of amorphous silicon. The method crystallizes amorphous silicon selectively to provide an organic light-emitting display device that includes channel area of a pixel contains polycrystalline silicon and storage area of the pixel contains amorphous silicon.

Description:
CROSS-REFERENCE TO RELATED PATENT APPLICATION 
       [0001]    This application claims the benefit of Korean Patent Application No. 10-2010-0079229, filed on Aug. 17, 2010, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference. 
       BACKGROUND 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to display technology, and more particularly, to organic light-emitting display devices. 
         [0004]    2. Description of the Related Art 
         [0005]    An active matrix (AM)-type organic light-emitting display device includes a plurality of pixels each including a pixel driving circuit including a thin-film transistor (TFT) formed of silicon. Amorphous silicon or polycrystalline silicon is used in the TFTs. 
         [0006]    An amorphous silicon TFT (a-Si TFT) used in a pixel driving circuit has a low electron mobility of 1 cm 2 /Vs or less since a semiconductor activation layer that constitutes a source, a drain, and a channel is formed of a-Si. Recently, the a-Si TFT has been replaced with a polycrystalline silicon TFT (poly-Si TFT). The poly-Si TFT has higher electron mobility and higher stability with respect to light than the a-Si TFT. Accordingly, poly-Si is suitable for use in an activation layer of a driving and/or switching TFT of an AM organic light-emitting display device. 
         [0007]    Poly-Si may be formed using various methods. The poly-Si formation may be largely divided into a method of directly depositing poly-Si and a method of depositing a-Si and crystallizing the a-Si. 
         [0008]    Examples of the direct deposition method include chemical vapor deposition (CVD), Photo CVD, hydrogen radical (HR) CVD, electron cyclotron resonance (ECR) CVD, plasma enhanced (PE) CVD, and low pressure (LP) CVD. 
         [0009]    Examples of the crystallization method in which a-Si is deposited and then crystallized include solid phase crystallization (SPC), excimer laser crystallization (ELC), metal induced crystallization (MIC), metal induced lateral crystallization (MILC), and sequential lateral solidification (SLS). 
         [0010]      FIG. 1  is a schematic view of a crystallization device  9  for crystallizing deposited a-Si. The crystallization device  9  includes a laser generator  91  for generating a laser beam L, a focusing lens  92  for focusing the laser beam L emitted from the laser generator  91 , and a reduction lens  93  for reducing the laser beam L that has passed through the focusing lens  92  by a given magnification. 
         [0011]    In the laser generator  91 , a laser beam L that is not processed is emitted from a light source and passes through an attenuator (not shown) so that intensity of energy of the laser beam L is controlled, and the controlled laser beam L is irradiated through the focusing lens  92 . 
         [0012]    Meanwhile, an x-y stage  94  on which a substrate  10  on which a-Si layer is deposited is located corresponding to the laser generator  91 . In this case, in order to crystallize the entire area of the substrate  10 , the x-y stage  94  need to be horizontally moved. 
         [0013]    A method of crystallizing silicon using a conventional crystallization device as described above will now be described in detail. In order to deposit crystalline silicon on a substrate, an insulating layer (called “buffer layer, not shown) is formed on the substrate, and an a-Si layer is deposited on the buffer layer and crystallized with the application of a laser beam to the deposited a-Si layer. Typically, the a-Si layer is deposited on the substrate by CVD. 
         [0014]    However, when crystallization is performed using a laser beam, the entire area of the substrate, that is, both a pixel area and a circuit area are crystallized. In the pixel area, a channel area, a storage area, and an emission area are all crystallized. In addition, due to the limited width of the laser beam, crystallization is performed while moving the laser generator or the substrate with respect to each other. However, organic light-emitting display devices are manufactured as large devices, and accordingly, the area to be crystallized is increased. Therefore, maintenance expenses for generating a laser beam by a laser generator are increased. 
         [0015]    The foregoing discussion is to provide background information relating to the invention disclosed in this application and does not constitute an admission of prior art. 
       SUMMARY 
       [0016]    One aspect of the present invention provides an organic light-emitting display device capable of improving efficiency of a laser used for crystallization and reducing a maintenance expense for generating the laser and a method of manufacturing the same. 
         [0017]    According to an aspect of the present invention, there is provided an organic light-emitting display device including: a thin-film transistor including an activation layer, a gate electrode, and source and drain electrodes; an organic light-emitting device including a pixel electrode electrically connected to the thin-film transistor, an intermediate layer including an emissive layer, and an opposite electrode which are sequentially deposited in the stated order; a storage capacitor including a first capacitor electrode formed on the same plane as the activation layer and a second capacitor electrode that is separated from the first capacitor electrode by a first insulating layer and faces the first capacitor electrode; and a connection electrode electrically connecting the activation layer to the first capacitor electrode. 
         [0018]    The activation layer includes polycrystalline silicon and the first capacitor electrode includes amorphous silicon. The connection electrode includes the same material on the same plane as the gate electrode. The first insulating layer covers the activation layer and the first capacitor electrode, and contact holes are formed in areas of the first insulating layer corresponding to the activation layer and the first capacitor electrode, and through the contact holes, the connection electrode electrically connects the activation layer to the first capacitor electrode. The connection electrode includes the same material on the same plane as the source and drain electrodes. 
         [0019]    The organic light-emitting display device may further include a second insulating layer, wherein the first insulating layer and the second insulating layer cover the activation layer and the first capacitor electrode, and contact holes are formed in areas of the first insulating layer and the second insulating layer corresponding to the activation layer and the first capacitor electrode and through the contact holes, the connection electrode electrically connects the activation layer to the first capacitor electrode. 
         [0020]    According to another aspect of the present invention, there is provided an organic light-emitting display device including: an activation layer formed on a substrate and a first capacitor electrode that is formed on the same plane as the activation layer and is spaced apart from the activation layer; a first insulating layer covering the activation layer and the first capacitor electrode; a gate electrode formed on the first insulating layer and a connection electrode that includes the same material on the same plane as the gate electrode, is spaced apart from the gate electrode, and electrically connects the activation layer to the first capacitor electrode; a second insulating layer covering the gate electrode and the connection electrode; source and drain electrodes formed on the second insulating layer and a second capacitor electrode that includes the same material on the same plane as the source and drain electrodes, and is spaced apart from the source and drain electrodes; and an organic light-emitting device including a pixel electrode electrically connected to the source and drain electrodes, an intermediate layer including an emissive layer, and an opposite electrode which are sequentially deposited in the stated order. The activation layer includes polycrystalline silicon and the first capacitor electrode includes amorphous silicon. 
         [0021]    According to another aspect of the present invention, there is provided an organic light-emitting display device including: an activation layer formed on a substrate and a first capacitor electrode that is formed on the same plane as the activation layer and is spaced apart from the activation layer; a first insulating layer covering the activation layer and the first capacitor electrode; a gate electrode formed on the first insulating layer and a second capacitor electrode that includes the same material on the same plane as the gate electrode, and is spaced apart from the gate electrode; a second insulating layer covering the gate electrode and the second capacitor electrode; source and drain electrodes formed on the second insulating layer and a connection electrode that includes the same material on the same plane as the source and drain electrodes and electrically connects the activation layer to the first capacitor electrode; and an organic light-emitting device including a pixel electrode electrically connected to the source and drain electrodes, an intermediate layer including an emissive layer, and an opposite electrode which are sequentially deposited in the stated order. The activation layer includes polycrystalline silicon and the first capacitor electrode includes amorphous silicon. 
         [0022]    According to another aspect of the present invention, there is provided an organic light-emitting display device including: a pixel area in which a plurality of pixels are formed, wherein each of the pixels includes a thin-film transistor, an organic light-emitting device electrically connected to the thin-film transistor, and a storage capacitor that is spaced apart from the thin-film transistor and is electrically connected to the thin-film transistor; and a circuit area located one a side of the pixel area and supplying a power signal and an electric signal to the pixel area, wherein a semiconducting layer formed in the circuit area includes polycrystalline silicon and a semiconducting layer formed in the pixel area is formed by alternately depositing polycrystalline silicon and amorphous silicon. 
         [0023]    The thin-film transistor includes a semiconducting layer including polycrystalline silicon, and the storage capacitor includes a semiconducting layer including amorphous silicon. The semiconducting layer of the thin-film transistor is electrically connected to the semiconducting layer of the storage capacitor. 
         [0024]    According to another aspect of the present invention, there is provided a method of manufacturing an organic light-emitting display device, the method including: depositing a semiconducting layer on a substrate; selectively crystallizing a portion of the semiconducting layer; patterning the semiconducting layer to form an activation layer and a first capacitor electrode; forming a first insulating layer having contact holes respectively exposing a portion of the activation layer and a portion of the first capacitor electrode; forming a gate electrode and a connection electrode contacting each of the exposed portion of the activation layer and the exposed portion of the first capacitor electrode; forming a second insulating layer having contact holes exposing portions of ends of the activation layer; and forming source and drain electrodes and a second capacitor electrode contacting the exposed portions of the activation layer. 
         [0025]    In the selective crystallizing, an area of the semiconducting layer in which the activation layer is to be formed is crystallized. In the selective crystallizing, while a laser generator moves with respect to the substrate to perform crystallization, only when the laser generator passes an area of the semiconducting layer in which the activation layer is to be formed, the laser generator is turned on. 
         [0026]    According to another aspect of the present invention, there is provided a method of manufacturing an organic light-emitting display device, wherein the method includes depositing a semiconducting layer on a substrate; selectively crystallizing a portion of the semiconducting layer; patterning the semiconducting layer to form an activation layer and a first capacitor electrode; forming a first insulating layer on the activation layer and the first capacitor electrode and a gate electrode and a second capacitor electrode on the first insulating layer; forming second insulating layer on the gate electrode and the second capacitor electrode; patterning the first insulating layer and the second insulating layer to form a first contact hole exposing portions of ends of the activation layer and a second contact hole exposing a portion of each of the activation layer and the first capacitor electrode; and forming source and drain electrodes contacting the exposed portions of the activation layer and a connection electrode contacting the exposed portion of each of the activation layer and the first capacitor electrode. 
         [0027]    In the selective crystallizing, an area of the semiconducting layer in which the activation layer is to be formed is crystallized. In the selective crystallizing, while a laser generator moves with respect to the substrate to perform crystallization, only when the laser generator passes an area of the semiconducting layer in which the activation layer is to be formed, the laser generator is turned on. 
         [0028]    According to another aspect of the present invention, there is provided a method of manufacturing an organic light-emitting display device including a pixel area and a circuit area, wherein the method includes when crystallization is performed on a semiconducting layer in the circuit area, crystallization is performed while a laser generator continues to be turned on, and when crystallization is performed on a semiconducting layer in the pixel area, crystallization is performed while the laser generator is periodically turned on and off. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0029]    The above and other features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings in which: 
           [0030]      FIG. 1  is a schematic view of a crystallization device for crystallizing deposited amorphous silicon (a-Si); 
           [0031]      FIG. 2  is a schematic plane view of an organic light-emitting display device according to an embodiment of the present invention; 
           [0032]      FIG. 3  illustrates a process for crystallizing a substrate by irradiation of a laser beam by a laser generator, according to an embodiment of the present invention; 
           [0033]      FIG. 4  illustrates a process for crystallizing a substrate by irradiation of a laser beam by a laser generator, according to another embodiment of the present invention; 
           [0034]      FIG. 5  is a plane view of a pixel that constitutes the organic light-emitting display device of  FIG. 2 , according to an embodiment of the present invention; 
           [0035]      FIG. 6  is a plane view of a pixel that constitutes the organic light-emitting display device of  FIG. 2 , according to another embodiment of the present invention; 
           [0036]      FIG. 7  is a sectional view of a pixel that constitutes the organic light-emitting display device of  FIG. 2 , according to an embodiment of the present invention; 
           [0037]      FIG. 8  is a graph of a capacitance with respect to a voltage of a capacitor electrode in a storage area when the capacitor electrode is formed of polycrystalline silicon; 
           [0038]      FIG. 9  is a graph of a capacitance with respect to a voltage of a capacitor electrode in a storage area when the capacitor electrode is formed of amorphous silicon and is electrically connected to an activation layer in a channel area; 
           [0039]      FIGS. 10 through 20  are sectional views schematically illustrating a method of manufacturing the organic light-emitting display device of  FIG. 7 ; and 
           [0040]      FIG. 21  is a sectional view of a pixel that constitutes the organic light-emitting display device of  FIG. 2 , according to another embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0041]    Reference will now be made in detail to embodiments, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. In this regard, the present embodiments may have different forms and should not be construed as being limited to the descriptions set forth herein. Accordingly, the embodiments are merely described below, by referring to the figures, to explain aspects of the present description. 
         [0042]      FIG. 2  is a schematic plane view of an organic light-emitting display device  1  according to an embodiment of the present invention. The organic light-emitting display device  1  according to the present embodiment includes a first substrate  10  including a thin-film transistor (TFT) and a luminous pixel, and a second substrate (not shown) that is coupled to the first substrate  10  by sealing. For example, a TFT, an organic light-emitting device (EL), and a storage capacitor Cst may be formed on the first substrate  10 . The first substrate  10  may be a low-temperature poly-silicon (LTPS) substrate, a glass substrate, a plastic substrate, or a stainless steel (SUS) substrate. 
         [0043]    The second substrate may be an encapsulation substrate that is disposed on the first substrate  10  and blocks permeation of external water molecules and the air into, for example, the TFT and the luminous pixel formed on the first substrate  10 . The second substrate is located facing the first substrate  10 , and the first substrate  10  is coupled to the second substrate with sealing  12  formed along the edges of the first substrate  10 . The second substrate may be a transparent glass substrate or transparent plastic substrate. 
         [0044]    The first substrate  10  may include a pixel area PA from which light is emitted and a circuit area CA located outside the pixel area PA. According to embodiments of the present invention, the sealing  12  is formed outside the pixel area PA and is used to couple the first substrate  10  to the second substrate. 
         [0045]    As described above, an organic light-emitting device (EL), a TFT for driving the organic light-emitting device, and an interconnection line electrically connected to the organic light-emitting device and the TFT are formed in the pixel area PA of the first substrate  10 . The pixel area PA includes an array of organic light-emitting pixels arranged to display information and data. In the circuit area CA, there is a pad electrode PE extending from the interconnection line of the pixel area PA. 
         [0046]    In regard to the organic light-emitting display device  1 , a semiconducting layer formed in the pixel area PA is subjected to full crystallization, and a semiconducting layer formed in the circuit area CA is subjected to selective crystallization. 
         [0047]    In detail, according to a conventional crystallization method using a laser beam, the entire area of a substrate including the pixel area and the circuit area is crystallized, and in the pixel area, a channel area, a storage area, and an emission area all are crystallized. However, an organic light-emitting display device is manufactured as a large device and accordingly, an area to be crystallized is increased. Therefore, a maintenance expense for generating a laser beam by a laser generator is increased and productivity is decreased. 
         [0048]    In order to solve the problems described above, according to embodiments, full crystallization is performed for the circuit area CA, where high electron mobility is needed, and selective crystallization is performed for the pixel area PA, where high electron mobility is needed only in some portions, for example, TFTs. That is, only the particular portion requiring high electron mobility is crystallized. The full crystallization and selective crystallization may be performed by turning on or off a laser. More specifically, when the circuit area CA is crystallized, the laser generator is turned on and crystallization is performed while the substrate  10  or the laser generator is moving with respect to each other. On the other hand, when the pixel area PA is crystallized, the laser generator is selectively turned on and off. For example, the laser generator is turned off when the laser generator passes areas that do not require high electron mobility and remains turned off until the laser generator reaches or focuses areas, e.g., TFTs that require high electron mobility. When the laser generator passes or focuses TFTs, the laser generator is turned on and performs crystallization on the TFT. 
         [0049]    Referring to  FIGS. 3A through 3C , when the substrate  10  moves with respect to the laser generator (not shown) and the circuit area CA of the substrate  10  passes a laser beam L irradiated by the laser generator, the substrate  10  is crystallized while the laser generator is turned on. On the other hand, when the laser generator moves over the pixel area PA of the substrate  10 , the laser generator is turned off and in this state, the substrate  10  moves in a direction indicated by an arrow until the laser generator reaches an area to be crystallized, for example, the TFT, and then the laser generator is turned on and performs crystallization on the TFT. 
         [0050]    As described above, since the pixel area PA and the circuit area CA are crystallized using different crystallization methods, that is, the circuit area CA is subjected to the full crystallization and the pixel area PA is subjected to the selective crystallization, efficiency of the laser generator is maximized, the operating costs can be reduced. 
         [0051]      FIG. 4  illustrates a process for crystallizing the substrate  10  by irradiation of the laser beam L by the laser generator, according to another embodiment of the present invention. Referring to  FIG. 4 , when an organic light-emitting display device is manufactured as a large device, a plurality of panels (that is, a plurality of organic light-emitting display devices) may be formed on a mother glass. In this case, as illustrated in  FIG. 4 , when the panels are aligned in two columns, the panels are oriented such that circuit areas CA of two neighboring panels of a row are located next to each other. In this arrangement of panels, two circuit areas CA of the two neighboring panels can be crystallized continuously without turning off while crystallizing the two circuit areas of a single row. 
         [0052]    Hereinafter, one pixel of the pixel area PA of the organic light-emitting display device  1  will be described in detail. 
         [0053]      FIG. 5  is a plane view of a pixel that constitutes the organic light-emitting display device  1  of  FIG. 2 , according to an embodiment of the present invention, and  FIG. 6  is a plane view of a pixel that constitutes the organic light-emitting display device  1  of  FIG. 2 , according to another embodiment of the present invention. 
         [0054]    Referring to  FIGS. 5 and 6 , the pixel of the organic light-emitting display device  1  includes a channel area  2 , a storage area  3 , and an emission area  4 . In  FIG. 5 , the channel area  2 , the storage area  3 , and the emission area  4  are aligned parallel to each other, and in  FIG. 6 , the storage area  3  and the emission area  4  are formed long in their lengthwise directions and neighbor each other, and the channel area  2  is located on a side of each of the storage area  3  and the emission area  4  and neighbors with each of the storage area  3  and the emission area  4 . 
         [0055]    In this case, as illustrated in  FIGS. 5 and 6 , even in one pixel, only the channel area  2  and the storage area  3  require high electron mobility, and the emission area  4 , which occupies more than half the entire area of the pixel, does not require high electron mobility. Accordingly, there is a need to crystallize only the channel area  2  and the storage area  3 . However, the storage area  3  also occupies a wide space similar to that required for the channel area  2 . Thus, if the storage area  3  is not crystallized and amorphous silicon is used to form an electrode in the storage area  3 , crystallization needs to be performed only on the channel area  2 , which is just a small part of the entire region of the pixel. Therefore, a laser maintenance expense may be reduced and a laser may be efficiently used. 
         [0056]    To do this, in the organic light-emitting display device  1 , only a semiconducting layer formed in the channel area  2  is selectively crystallized so as to form an activation layer formed of polycrystalline silicon, and a semiconducting layer formed in the storage area  3  is not crystallized so as to form a first capacitor electrode formed of amorphous silicon. A contact hole is formed in an insulating layer covering the activation layer and the first capacitor electrode, and the activation layer is electrically connected to the first capacitor electrode through the contact hole, thereby allowing the first capacitor electrode to perform as an electrode. This structure described above will be now described in detail. 
         [0057]      FIG. 7  is a sectional view of a pixel that constitutes the organic light-emitting display device  1  of  FIG. 2 , according to an embodiment of the present invention. Referring to  FIG. 7 , the pixel of the organic light-emitting display device  1  includes a channel area  2 , a storage area  3 , and an emission area  4 . 
         [0058]    A TFT as a driving device is formed in the channel area  2 . The TFT includes an activation layer  211 , a gate electrode  214 , and source and drain electrodes  216   a  and  216   b.  A first insulating layer  13  is interposed between the gate electrode  214  and the activation layer  211  so that the gate electrode  214  is insulated from the activation layer  211 . In addition, source and drain areas in which high-concentration impurities are implanted are formed in ends of the activation layer  211  and are respectively connected to the source and drain electrodes  216   a  and  216   b.    
         [0059]    A storage capacitor Cst is formed in the storage area  3 . The storage capacitor Cst includes a first capacitor electrode  311  and a second capacitor electrode  316 , and the first insulating layer  13  is interposed between the first capacitor electrode  311  and the second capacitor electrode  316 . The first capacitor electrode  311  may be formed of the same material on the same plane as the activation layer  211  of the TFT. Also, the second capacitor electrode  316  may be formed of the same material on the same plane as the source and drain electrodes  216   a  and  216   b  of the TFT. 
         [0060]    In the present embodiment, the activation layer  211  of the channel area  2  is formed of polycrystalline silicon, and the first capacitor electrode  311  of the storage area  3  that is formed on the same plane as the activation layer  211  is formed of amorphous silicon. That is, a semiconducting layer formed of amorphous silicon is deposited on the substrate  10 , and then crystallization is selectively performed so that the amorphous silicon in the channel area  2  (activation layer  211 ) is crystallized into polycrystalline silicon and the amorphous silicon in the storage area  3  (first capacitor electrode  311 ) is not crystallized. 
         [0061]    Also, the organic light-emitting display device  1  may further include a connection electrode  314  that electrically connects the activation layer  211  of the channel area  2  and the first capacitor electrode  311  of the storage area  3 . Referring to  FIG. 13 , contact holes H 1  and H 2  are formed in the first insulating layer  13  covering the activation layer  211  of the channel area  2  and the first capacitor electrode  311  of the storage area  3 , and then the contact holes H 1  and H 2  are filled with the material of the connection electrode  314  formed on the first insulating layer  13  so that the activation layer  211  of the channel area  2  is electrically connected to the first capacitor electrode  311  of the storage area  3 . In embodiments, the connection electrode  314  may be formed of the same material on the same plane as the gate electrode  214  of the channel area  2 . 
         [0062]    An organic light-emitting device EL is formed in the emission area  4 . The organic light-emitting device EL includes a pixel electrode  418  connected to one of the source and drain electrodes  216   a  and  216   b  of the TFT, an opposite electrode (common electrode)  421  facing the pixel electrode  418 , and an intermediate layer  420  interposed between the pixel electrode  418  and the opposite electrode  421 . The pixel electrode  418  may be formed of a transparent conductive material. 
         [0063]      FIG. 8  is a graph of capacitance of the storage capacitor Cst with respect to the voltage of capacitor electrode  311  in the storage area  3  when the capacitor electrode  311  is formed of polycrystalline silicon.  FIG. 9  is a graph of capacitance of the storage capacitor Cst with respect to the voltage of capacitor electrode  311  in the storage area  3  when the capacitor electrode  311  is formed of amorphous silicon and is electrically connected to the activation layer  211  in a channel area, according to an embodiment of the present invention. 
         [0064]    Referring to  FIG. 8 , when the capacitor electrode  311  of the storage area  2  is formed of polycrystalline silicon, the capacitance of a storage capacitor Cst is about 1.4e −11  F to about 1.6e −11 . Referring to  FIG. 9 , when the capacitor electrode  311  of the storage area  3  is formed of amorphous silicon and is electrically connected to the activation layer of the channel area, the capacitance of a storage capacitor Cst is about 0.6e −11  F to 1.6e −11 . The capacitance of  FIG. 9  is slightly less than the capacitance of  FIG. 8 , but still enough for use as the storage capacitor Cst. These experimental results indicate that the electrical connection between the activation layer  211  of the channel area  2  and the first capacitor electrode  311  of the storage area  3  enables use of amorphous silicon instead of polycrystalline silicon in the capacitor electrode of the storage area  3 . 
         [0065]    Hereinafter, a method of manufacturing the organic light-emitting display device  1  of  FIG. 7 , which is a bottom emission type, will be described in detail.  FIGS. 10 through 20  are sectional views schematically illustrating a method of manufacturing the organic light-emitting display device  1  of  FIG. 7 . 
         [0066]    First, as illustrated in  FIG. 10 , the semiconducting layer  11  is deposited on the substrate  10 . In embodiments, the substrate  10  may be formed of a transparent glass material mainly composed of SiO 2 . However, the substrate  10  is not necessarily limited thereto and may be instead formed of various other materials such as a transparent plastic material or a metal. Then, a semiconducting or semiconductive layer  11  is formed over the substrate  10 . The semiconducting layer  11  may be formed by, for example, chemical vapor deposition (CVD), Photo CVD, hydrogen radical (HR) CVD, electron cyclotron resonance (ECR) CVD, plasma enhanced (PE) CVD, or low pressure (LP) CVD. In this regard, the semiconducting layer  11  may be an amorphous silicon layer. 
         [0067]    Also, before the semiconducting layer  11  is deposited, an insulating layer (not shown) may be formed over the substrate  10  as a barrier layer or a buffer layer for preventing diffusion of impurity ions, preventing permeation of water molecules and an external gas, and planarizing a surface of the substrate  10 . The insulating layer may be formed of depositing, for example, SiO 2  and/or SiN x , on the substrate  10  by any one of various deposition methods including plasma enhanced chemical vapor deposition (PECVD), atmospheric pressure CVD (APCVD), and low pressure CVD (LPCVD). 
         [0068]    Next, as illustrated in  FIG. 11 , a laser generator  91  moves relative to the substrate  10  over the substrate  10 , while radiating one or more laser beams to the substrate  10 . The laser generator  91  is selectively turned on and off during the movement relative to the substrate  10  so as to crystallize selective areas of the semiconducting layer  11 . In the illustrated embodiment, only the area  11   a  is crystallized and becomes the activation layer  211  (see also  FIG. 7 ) of the channel area  2 . Similarly, selected areas of the substrate  10  are crystallized with selective turning on and off of the laser generator  91  while moving relative to the substrate  10 . In  FIG. 11 , a waveform of a laser beam in only one pixel is illustrated. However, when the laser generator  91  passes other pixels, the waveform of the laser beam of  FIG. 11  may repeatedly occur. 
         [0069]    The semiconducting layer  11  may be crystallized by, for example, rapid thermal annealing (RTA), solid phase crystallization (SPC), excimer laser annealing (ELA), metal induced crystallization (MIC), metal induced lateral crystallization (MILC), or sequential lateral solidification (SLS). 
         [0070]    Subsequently, as illustrated in  FIG. 12 , the semiconducting layer  11  is patterned to form the activation layer  211  of the TFT and the first capacitor electrode  311  of the storage capacitor Cst. That is, the semiconducting layer  11  may be patterned to form the activation layer  211  of the TFT and the first capacitor electrode  311  of the storage capacitor Cst by using a mask process using a first mask (not shown). In embodiments, the activation layer  211  of the TFT is formed of polycrystalline silicon and the first capacitor electrode  311  of the storage capacitor Cst is formed of amorphous silicon. In the present embodiment, the activation layer  211  and the first capacitor electrode  311  are spaced from each other. However, in another embodiment, the activation layer  211  and the first capacitor electrode  311  may be formed as one body. 
         [0071]    Then, as illustrated in  FIG. 13 , the first insulating layer  13  is formed on the entire surface of the substrate  10  on which the activation layer  211  and the first capacitor electrode  311  are formed, and then contact holes H 1  and H 2  are formed in the first insulating layer  13 . In embodiments, the first insulating layer  13  may be formed by depositing an inorganic insulating material, such as SiN x  or SiO x , by PECVD, APCVD, or LPCVD. The first insulating layer  13  is interposed between the activation layer  211  and the gate electrode  214  of the TFT and functions as a gate insulating layer of the TFT, and also interposed between the second capacitor electrode  315  and the first capacitor electrode  311  and functions as a dielectric layer of the capacitor Cst. Then, the first insulating layer  13  is patterned using a mask process using a second mask (not shown) so as to form contact holes H 1  and H 2 . In embodiments, the contact hole H 1  exposes a portion of the activation layer  211 , and the contact hole H 2  exposes a portion of the first capacitor electrode  311 . 
         [0072]    Then, as illustrated in  FIG. 14 , a first conductive layer  14  is deposited on the first insulating layer  13 . In embodiments, the first conductive layer  14  may include at least one transparent material selected from the group consisting of ITO, IZO, ZnO, and In 2 O 3 . Alternately, the first conductive layer  14  may include at least one material selected from the group consisting of Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, Mo, Ti, W, MoW, and Al/Cu. The first conductive layer  14  may have such a thickness that the first conductive layer  14  sufficiently fills the contact holes H 1  and H 2 . 
         [0073]    Subsequently, as illustrated in  FIG. 15 , the first conductive layer  14  is patterned to form the gate electrode  214  and the connection electrode  314  of the TFT. That is, the first conductive layer  14  is patterned to form the gate electrode  214  and the connection electrode  314  of the TFT by using a mask process using a third mask (not shown). The connection electrode  314  electrically connects the activation layer  211  to the first capacitor electrode  311 , and enables the first capacitor electrode  311  formed of amorphous silicon to function as an electrode. 
         [0074]    Then, as illustrated in  FIG. 16 , a second insulating layer  15  is deposited on the entire surface of the substrate  10  on which the first insulating layer  13 , the gate electrode  214 , and the connection electrode  314  are formed, and then, contact holes H 3  and H 4  are formed in the second insulating layer  15 . 
         [0075]    The second insulating layer  15  may be formed by, for example, spin coating at least one organic insulating material selected from the group consisting of polyimide, polyamide, an acryl resin, benzocyclobuten, and a phenol resin. The second insulating layer  15  may have a sufficient thickness. For example, the thickness of the second insulating layer  15  may be greater than the thickness of the first insulating layer  13  and functions as an interlayer insulating layer between the gate electrode  214  and the source and drain electrodes (see  216   a  and  216   b  of  FIG. 7 ) of the TFT. Alternately, the second insulating layer  15  may be formed of inorganic insulating materials used for forming the first insulating layer  13 , instead of the organic insulating materials described above. Alternately, the second insulating layer  15  may be formed by alternately depositing an organic insulating material and an inorganic insulating material. 
         [0076]    The second insulating layer  15  is patterned using a mask process using a fourth mask (not shown) to form contact holes H 3  and H 4 . In embodiments, the contact holes H 3  and H 4  expose portions of source and drain areas in ends of the activation layer  211 . 
         [0077]    Then, as illustrated in  FIG. 17 , the second conductive layer  16  is deposited on the entire surface of the substrate  10  to cover the second insulating layer  15 . The second conductive layer  16  may be formed of at least one material selected from the group consisting of the conductive materials used to form the first conductive layer  14 . However, the second conductive layer  16  may instead be formed of various other conductive materials. The second conductive layer  16  may have such a thickness that the second conductive layer  16  fills the contact holes H 3  and H 4 . 
         [0078]    Then, as illustrated in  FIG. 18 , the second conductive layer (see  16  of  FIG. 17 ) is patterned to form the source and drain electrodes  216   a  and  216   b  and the second capacitor electrode  316 . In embodiments, the second conductive layer (see  16  of  FIG. 17 ) is patterned using a mask process using a fifth mask (not shown) to form the source and drain electrodes  216   a  and  216   b  and the second capacitor electrode  316 . Accordingly, the source and drain electrodes  216   a  and  216   b  and the second capacitor electrode  316  are formed of the same material on the same plane. 
         [0079]    Then, as illustrated in  FIG. 19 , a third insulating layer  17  is deposited on the entire surface of the substrate  10  on which the second insulating layer  15 , the source and drain electrodes  216   a  and  216   b,  and the second capacitor electrode  316  are formed, and then a contact hole H 5  is formed in the third insulating layer  17 . In embodiments, the third insulating layer  17  may be formed by depositing an inorganic insulating material, such as SiN x  or SiO x , by PECVD, APCVD, or LPCVD. The third insulating layer  17  may function as a passivation layer. The third insulating layer  17  is patterned using a mask process using a sixth mask (not shown) to form a contact hole H 5 . In embodiments, the contact hole H 5  may expose a portion of the source and drain electrodes  216   a  and  216   b.    
         [0080]    Then, as illustrated in  FIG. 20 , a fourth conductive layer (not shown) covering the third insulating layer  17  is deposited on the entire surface of the substrate  10 , and then patterned to form the pixel electrode  418 . Then, as illustrated in  FIG. 7 , a pixel define layer (PDL)  19  covering ends of the pixel electrode  418  is formed, and then, the intermediate layer  420  including an organic emissive layer and the opposite electrode  421  are formed in an emission area defined by the PDL  19 . The intermediate layer  420  may include an emissive layer (EML), and at least one layer selected from the group consisting of a hole transport layer (HTL), a hole injection layer (HIL), an electron transport layer (ETL), and an electron injection layer (EIL), wherein each layer may have a mono-layer structure or a multi-layer structure. 
         [0081]    The intermediate layer  420  may be formed of a low molecular weight organic material or a polymer organic material. When the intermediate layer  420  is formed of a low molecular weight organic material, the intermediate layer  420  may include a HTL and a HIL sequentially deposited in the stated order in a direction from the EML to the pixel electrode  418 , and an ETL and an EIL sequentially deposited in the stated order in a direction from the EML to the opposite electrode  421 . The intermediate layer  420  may further include various other layers according to a purpose. In embodiments, an available organic material may be, for example, copper phthalocyanine (CuPc), N,N′-Dinaphthalene-1-yl-N,N′-diphenyl-benzidine (NPB), or tris-8-hydroxyquinoline aluminum (Alq3). 
         [0082]    Also, when the intermediate layer  420  is formed of a polymer organic material, the intermediate layer  420  may include only a HTL in a direction from the EML to the pixel electrode  418 . The HTL may be formed by ink-jet printing or spin coating poly-2,4-ethylene-dihydroxy thiophene (PEDOT) or polyaniline (PANI) on the pixel electrode  418 . In embodiments, an available organic material may be, for example, a poly-phenylenevinylene (PPV)-based organic material or a polyfluorene-based organic material, and a color pattern may be formed using a conventional method such as ink-jet printing, spin coating, or thermal transferring using a laser. 
         [0083]    In some embodiments, the opposite electrode  421  may be deposited on the entire surface of the substrate  10  and functions as a common electrode. In the organic light-emitting display device  1 , the pixel electrode  418  is used as an anode, and the opposite electrode  421  is used as a cathode. Alternately, in another embodiment, the pixel electrode  418  may be used as a cathode, and the opposite electrode  421  may be used as an anode. 
         [0084]    If the organic light-emitting display device  1  is a bottom emission-type organic light-emitting display device in which an image is formed toward the substrate  10 , the pixel electrode  418  may be a transparent electrode and the opposite electrode  421  may be a reflective electrode. In embodiments, the reflective electrode may be formed by depositing a metal having a low work function, for example, Ag, Mg, Al, Pt, Pd, Au, Ni, Nd, Ir, Cr, Li, Ca, LiF/Ca, LiF/Al, or a combination thereof, and the formed reflective electrode may have a small thickness. 
         [0085]      FIG. 21  is a sectional view of a pixel that constitutes the organic light-emitting display device  1  of  FIG. 2 , according to another embodiment of the present invention. Referring to  FIG. 21 , the pixel of the organic light-emitting display device  1 ′ according to the present embodiment includes a channel area  2 , storage area  3 , and an emission area  4 . In embodiments, the pixel of the organic light-emitting display device  1 ′ is different from the pixel of the previous embodiment in that the connection electrode  316  is formed on the same plane as the source and drain electrodes  216   a  and  216   b  instead of the gate electrode  214 . 
         [0086]    A TFT as a driving device is formed in the, channel area  2 . The TFT includes an activation layer  211 , a gate electrode  214 , and source and drain electrodes  216   a  and  216   b.  A first insulating layer  13  is interposed between the gate electrode  214  and the activation layer  211  so that the gate electrode  214  is insulated from the activation layer  211 . In addition, source and drain areas in which high-concentration impurities are implanted are formed in ends of the activation layer  211  and are respectively connected to the source and drain electrodes  216   a  and  216   b.    
         [0087]    A storage capacitor Cst is formed in the storage area  3 . The storage capacitor Cst includes a first capacitor electrode  311  and a second capacitor electrode  314 ′, and the first insulating layer  13  is interposed between the first capacitor electrode  311  and the second capacitor electrode  314 ′. The first capacitor electrode  311  may be formed of the same material on the same plane as the activation layer  211  of the TFT. Meanwhile, the second capacitor electrode  314 ′ may be formed of the same material on the same plane as the gate electrode  214  of the TFT. 
         [0088]    In the illustrated embodiment, the activation layer  211  of the channel area  2  is formed of polycrystalline silicon, and the first capacitor electrode  311  of the storage area  3  that is formed on the same plane as the activation layer  211  is formed of amorphous silicon. That is, a semiconducting layer formed of amorphous silicon is deposited on the substrate  10 , and then crystallization is selectively performed so that the amorphous silicon in the channel area  2  is crystallized into polycrystalline silicon and the amorphous silicon in the storage area  3  is not crystallized. 
         [0089]    Also, the organic light-emitting display device  1  may further include a connection electrode  316 ′ that electrically connects the activation layer  211  of the channel area  2  and the first capacitor electrode  311  of the storage area  3 . In embodiments, contact holes (see H 1  and H 2  of  FIG. 13 ) are formed in the first insulating layer  13  and a second insulating layer  15  which cover the activation layer  211  of the channel area  2  and the first capacitor electrode  311  of the storage area  3 , and then the contact holes are filled by the connection electrode  316 ′ formed on the first insulating layer  13  and the second insulating layer  15  so that the activation layer  211  of the channel area  2  is electrically connected to the first capacitor electrode  311  of the storage area  3 . In embodiments, the connection electrode  316 ′ may be formed of the same material on the same plane as the source and drain electrodes  216   a  and  216   b  of the channel area  2 . 
         [0090]    An organic light-emitting device (EL) is formed in the emission area  4 . The organic light-emitting device (EL) includes a pixel electrode  418  connected to one of the source and drain electrodes  216   a  and  216   b  of the TFT, an opposite electrode  421  facing the pixel electrode  418 , and an intermediate layer  420  interposed between the pixel electrode  418  and the opposite electrode  421 . The pixel electrode  418  may be formed of a transparent conductive material. 
         [0091]    As described above, according to above embodiments of the present invention, the efficiency of a laser used for crystallization is improved and the maintenance expense for generating the laser is reduced. 
         [0092]    While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims.