Patent Publication Number: US-9425426-B2

Title: Organic light emitting diode display having auxiliary electrode

Description:
INCORPORATION BY REFERENCE TO ANY PRIORITY APPLICATIONS 
     Any and all priority claims identified in the Application Data Sheet, or any correction thereto, are hereby incorporated by reference under 37 CFR 1.57. For example, this application is a divisional of U.S. patent application Ser. No. 14/205,088, filed Mar. 11, 2014, which claims priority to and the benefit of Korean Patent Application No. 10-2013-0122831 filed in the Korean Intellectual Property Office on Oct. 15, 2013, each disclosure of which is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND 
     1. Field 
     This disclosure relates to an organic light emitting diode display and a manufacturing method thereof For example, the present disclosure relates to an organic light emitting diode display including an auxiliary electrode and an absorption electrode. 
     2. Description of the Related Technology 
     An organic light emitting diode (OLED) display has been recently spotlighted as a display device for displaying images. 
     A conventional OLED display typically includes a first electrode, an organic emission layer disposed on the first electrode, and a second electrode disposed on the organic emission layer. 
     An OLED display may be classified into a front emission type, a rear emission type, and a dual emission type. The front emission type OLED display typically has a structure in which a second electrode of an organic light emitting element is formed over the entire area of a substrate where the organic light emitting element is formed in a thin film shape in order to minimize deterioration of luminance of light generated from an organic emission layer. 
     However, a voltage drop may occur in driving power passing through the second electrode for driving the organic emission layer due to electrical resistance of the second electrode since the second electrode formed as a thin film is formed over the entire area of the substrate in the front emission type of OLED display. 
     The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art. 
     SUMMARY 
     Some embodiments provide an organic light emitting diode (OLED) display that can minimize a voltage drop in driving power passing through a large-sized thin film electrode for driving an organic emission layer and can simplify a removal process of the organic emission layer on an auxiliary electrode by adding an absorption electrode on the auxiliary electrode, and a manufacturing method thereof. 
     Some embodiments provide an organic light emitting diode display including: a substrate; a first electrode and an auxiliary electrode positioned on the substrate and separated from each other; an absorption electrode positioned on the auxiliary electrode; an organic emission layer positioned on the first electrode and having a contact hole exposing the auxiliary electrode and the absorption electrode; and a second electrode positioned on the organic emission layer and connected to the auxiliary electrode and the absorption electrode through the contact hole. 
     In some embodiments, the second electrode may contact an etched surface of the contact hole, an upper surface of the auxiliary electrode, and an upper surface and a side surface of the absorption electrode. 
     In some embodiments, the absorption electrode may be made of one selected from molybdenum (Mo), titanium (Ti), tungsten (W), and chromium (Cr). 
     In some embodiments, the absorption electrode may be formed of a single layer or multiple layers. 
     In some embodiments, the absorption electrode may have a thickness of 300-1500 Å when the absorption electrode is formed of a single layer. 
     In some embodiments, an oxide layer may be further formed between the absorption electrode of the multiple layers when the absorption electrode is formed of multiple layers. 
     In some embodiments, the absorption electrode may be formed of dual layers, and an upper layer and a lower layer of the absorption electrode may respectively have thicknesses of 40-100 Å and 300-1000 Å. 
     In some embodiments, the oxide layer may be ITO or IZO. 
     In some embodiments, the absorption electrode may be formed with a line shape or a dot shape in a direction parallel to the auxiliary electrode on the auxiliary electrode. 
     In some embodiments, the organic light emitting diode display may further include: a gate line positioned on the substrate; a data line and a driving voltage line insulated from and intersecting the gate line and separated from each other; a switching thin film transistor connected to the gate line and the data line; and a driving thin film transistor connected to the switching thin film transistor and the driving voltage line, wherein the first electrode may be connected to a drain electrode of the driving thin film transistor. 
     Some embodiments provide an organic light emitting diode display includes: a substrate; a first electrode and an absorption electrode made of one selected from molybdenum (Mo), titanium (Ti), tungsten (W), and chromium (Cr), positioned on the substrate and separated from each other; an organic emission layer positioned on the first electrode and a contact hole exposing the absorption electrode; and a second electrode positioned on the organic emission layer and connected to the absorption electrode through the contact hole, wherein the absorption electrode is connected to the second electrode thereby having a function of an auxiliary electrode of the first electrode. 
     Some embodiments provide a manufacturing method of an organic light emitting diode display includes: forming a thin film transistor on a substrate; forming a first electrode connected to the thin film transistor and an auxiliary electrode separated from the first electrode; forming an absorption electrode on the auxiliary electrode; forming an organic emission layer on the first electrode, the auxiliary electrode, and the absorption electrode; irradiating an energy light source to the organic emission layer to etch the organic emission layer, thereby forming a contact hole having an opening exposing the auxiliary electrode and the absorption electrode; and depositing a metal layer on the organic emission layer to form a second electrode contacting an upper surface of the auxiliary electrode, an upper surface of the absorption electrode, and an etched surface of the opening in the contact hole. 
     In some embodiments, the etching of the organic emission layer may use a laser, a flash lamp, or a tungsten halogen lamp as an energy light source. 
     In some embodiments, the organic light emitting diode (OLED) display may minimize the voltage drop of the driving power passing through the large-sized electrode of the thin film for driving the organic emission layer, and may simplify the removal process of the organic emission layer on the auxiliary electrode by adding the absorption electrode on the auxiliary electrode. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a circuit diagram of a pixel circuit of an organic light emitting diode display according to an exemplary embodiment. 
         FIG. 2  is a layout view of one pixel of the organic light emitting diode display of  FIG. 1 . 
         FIG. 3  is a cross-sectional view taken along the line III-III of  FIG. 2 . 
         FIG. 4  is a layout view of one pixel of an organic light emitting diode display according to another exemplary embodiment. 
         FIG. 5  is a layout view of one pixel of an organic light emitting diode display according to another exemplary embodiment. 
         FIG. 6  is a cross-sectional view taken along the line VI-VI of  FIG. 5 . 
         FIGS. 7 to 13  are cross-sectional views sequentially showing a manufacturing method of an organic light emitting diode display according to another exemplary embodiment. 
         FIG. 14  is a graph showing a result of measuring absorbency according to a wavelength of light source energy for an absorption electrode that is formed of a single layer. 
         FIG. 15  is a graph showing a result of measuring absorbency according to a wavelength of light source energy for an absorption electrode that is formed of multiple layers. 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure will be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present embodiments. 
     In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. Like reference numerals designate like elements throughout the specification. It will be understood that when an element such as a layer, film, region, or substrate is referred to as being “on” another element, it can be directly on the other element or intervening elements may also be present. In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present. 
     An organic light emitting diode display and a manufacturing method thereof according to an exemplary embodiment will be described with reference to accompanying drawings. 
       FIG. 1  is a circuit diagram of a pixel circuit of an organic light emitting diode display according to an exemplary embodiment. 
     As shown in  FIG. 1 , an organic light emitting diode display according to the exemplary embodiment includes a plurality of signal lines  121 ,  171 , and  172  and a plurality of pixels (PX) connected thereto and arranged in an approximate matrix form. 
     The signal lines include a plurality of gate lines  121  transferring a gate signal (or a scan signal), a plurality of data lines  171  transferring a data signal, and a plurality of driving voltage lines  172  transferring a driving voltage Vdd. The gate lines  121  extend in an approximate row direction and are almost parallel to each other, and vertical direction portions of the data lines  171  and the driving voltage lines  172  extend in an approximate column direction and are almost parallel to each other. 
     Each pixel PX includes a switching thin film transistor Qs, a driving thin film transistor Qd, a storage capacitor Cst, and an organic light emitting diode (OLED)  70 . 
     The switching thin film transistor Qs has a control terminal, an input terminal, and an output terminal, the control terminal is connected to the gate line  121 , the input terminal is connected to the data line  171 , and the output terminal is connected to the driving thin film transistor Qd. The switching thin film transistor Qs transfers the data signal applied to the data line  171  to the driving thin film transistor Qd in response to the scan signal applied to the gate line  121 . 
     Further, the driving thin film transistor Qd has a control terminal, an input terminal, and an output terminal, and the control terminal is connected to the switching thin film transistor Qs, the input terminal is connected to the driving voltage line  172 , and the output terminal is connected to the organic light emitting diode  70 . The driving thin film transistor Qd allows an output current (ILD) having a varying magnitude according to a voltage applied between the control terminal and the output terminal to flow. 
     The capacitor Cst is connected between the control terminal and the input terminal of the driving thin film transistor Qd. This capacitor Cst charges the data signal applied to the control terminal of the driving thin film transistor Qd and maintains the data signal after the switching thin film transistor Qs is turned off. 
     The organic light emitting diode LD has an anode connected to the output terminal of the driving thin film transistor Qd, and a cathode connected to a common voltage Vss. The organic light emitting diode (LD) displays an image by emitting light while changing the intensity thereof according to the output current (ILD) of the driving thin film transistor Qd. 
     Further, the connection relationship of the thin film transistors Qs and Qd, the capacitor Cst, and the organic light emitting diode  70  may be changed. 
     The organic light emitting diode display in which the second electrode as a thin film type is entirely formed on the substrate including the organic light emitting element uses an auxiliary electrode forming the second electrode to prevent generation of a voltage drop to a power source passing through the second electrode to drive the organic emission layer by electric resistance of the second electrode. 
     However, a process of removing an organic layer to contact the auxiliary electrode and the first electrode is required and energy absorbency of the organic layer is low such that energy transmitting efficiency is largely decreased, and the removal process must be performed in a vacuum condition. 
     Next, an organic light emitting diode display according to an exemplary embodiment of the present invention will be described with reference to  FIG. 2  and  FIG. 3 . 
       FIG. 2  is a layout view of one pixel of the organic light emitting diode display of  FIG. 1 , and  FIG. 3  is a cross-sectional view taken along the line III-III of  FIG. 2 . 
     As shown in  FIG. 3 , a buffer layer  120  is formed on a substrate  100 . 
     In some embodiments, the substrate  100  may be an insulating substrate made of glass, quartz, ceramic, or a polymer material, or the substrate  100  may be a metallic substrate made of a stainless steel. In some embodiments, the polymer material may be an organic material selected from a group consisting of polyethersulfone (PES), polyacrylate (PAR), polyetherimide (PEI), polyethylene naphthalate (PEN), polyethylene terephthalate (PET), polyphenylene sulfide (PPS), polyallylate, polyimide, polycarbonate (PC), cellulose triacetate (TAC), and cellulose acetate propionate (CAP) that are insulating organic materials. 
     In some embodiments, the buffer layer  120  is formed on the substrate  100 . 
     In some embodiments, the buffer layer  120  may be formed to have a structure of a single layer of a silicon oxide (SiOx) or a silicon nitride (SiNx), or a plurality of layers where a silicon nitride (SiNx) and a silicon oxide (SiOx) are laminated. The buffer layer acts to prevent unnecessary components such as an impurity or moisture from permeating, and planarizes the surface. 
     In some embodiments, a first semiconductor  135   a  and a second semiconductor  135   b  may both be made of polysilicon and a first capacitor electrode  138  are formed on the buffer layer  120 . 
     In some embodiments, the first semiconductor  135   a  and the second semiconductor  135   b  may be divided into channel regions  1355   a  and  1355   b,  and source regions  1356   a  and  1356   b  and drain regions  1357   a  and  1357   b  respectively formed on both sides of the channel regions  1355   a  and  1355   b.  In some embodiments, the channel regions  1355   a  and  1355   b  of the first semiconductor  135   a  and the second semiconductor  135   b  are polysilicon into which impurities have not been doped, that is, intrinsic semiconductors. In some embodiments, the source regions  1356   a  and  1356   b  and the drain regions  1357   a  and  1357   b  of the first semiconductor  135   a  and the second semiconductor  135   b  are polysilicon into which conductive impurities have been doped, that is, impurity semiconductors. 
     In some embodiments, the impurities dopes into the source regions  1356   a  and  1356   b,  the drain regions  1357   a  and  1357   b,  and the first capacitor electrode  138  can be either p-type impurities or n-type impurities. 
     In some embodiments, a gate insulating layer  140  is formed on the first semiconductor  135   a,  the second semiconductor  135   b,  and the first capacitor electrode  138 . In some embodiments, the gate insulating layer  140  can be a single layer or a plurality of layers including at least one of tetraethyl orthosilicate (TEOS), a silicon nitride (SiNx), and a silicon oxide (SiO x ). 
     In some embodiments, the gate line  121 , a second gate electrode  155   b,  and a second capacitor electrode  158  are formed on the gate insulating layer  140 . 
     In some embodiments, the gate line  121  (shown in the perspective of  FIG. 2 ) lengthily extends in a horizontal direction and transfers a gate signal, and includes a first gate electrode  155   a  that is protruded from the gate line  121  to the first semiconductor  135   a.    
     In some embodiments, the first gate electrode  155   a  and the second gate electrode  155   b  overlap the respective channel regions  1355   a  and  1355   b,  and the second capacitor electrode  158  overlaps the first capacitor electrode  138 . 
     In some embodiments, each of the second capacitor electrode  158 , the first gate electrode  155   a,  and the second gate electrode  155   b  can have a single layer of a plurality of layers made of molybdenum, tungsten, copper, aluminum, or an alloy thereof. 
     In some embodiments, the first capacitor electrode  138  and the second capacitor electrode  158  form a capacitor Cst using the gate insulating layer  140  as a dielectric material. 
     In some embodiments, a first interlayer insulating layer  160  is formed on the first gate electrode  155   a,  the second gate electrode  155   b,  and the second capacitor electrode  158 . In some embodiments, the first interlayer insulating layer  160 , like the gate insulating layer  140 , can be made of tetraethyl orthosilicate (TEOS), a silicon nitride (SiNx), or a silicon oxide (SiO x ). 
     In some embodiments, the first interlayer insulating layer  160  and the gate insulating layer  140  include a source contact hole  166  and a drain contact hole  167  through which the source regions  1356   a  and  1356   b  and the drain regions  1357   a  and  1357   b  are exposed, respectively. 
     In some embodiments, the data lines  171  including a first source electrode  176   a,  the driving voltage lines  172  including a second source electrode  176   b,  a first drain electrode  177   a  (not shown), and a second drain electrode  177   b  are formed on the first interlayer insulating layer  160 . 
     In some embodiments, the data line  171  transmits a data signal and extends in a direction crossing the gate line  121 . 
     In some embodiments, the driving voltage line  172  transmits a predetermined voltage, and extends in the same direction as that of the data line  171  while being separated from the data line  171 . 
     In some embodiments, the first source electrode  176   a  protrudes toward the first semiconductor  135   a  from the data line  171 , and the second source electrode  176   b  protrudes toward the second semiconductor  135   b  from the driving voltage line  172 . In some embodiments, the first source electrode  176   a  and the second source electrode  176   b  are connected with the source regions  1356   a  and  1356   b  through the source contact holes  166 , respectively. 
     In some embodiments, the first drain electrode  177   a  (not shown) faces the first source electrode  176   a  and is connected with the drain region  1357   a  through the drain contact hole  167 . 
     The first drain electrode  177   a  (not shown) extends along the gate line, and is electrically connected with the second gate electrode  158   b  through a contact hole  81 . 
     In some embodiments, the second drain electrode  177   b  is connected with the drain region  1357   b  through the drain contact hole  167 . 
     In some embodiments, the data line  171 , the driving voltage line  172 , and the first drain electrode  177   a  may be formed as a single layer or a multilayer formed of a low resistance material, such as Al, Ti, Mo, Cu, Ni, or an alloy thereof, or a corrosion resistant material. For example, the data line  171 , the driving voltage line  172 , and the first drain electrode  177   a  may be triple layers of Ti/Cu/Ti or Ti/Ag/Ti. 
     In an exemplary embodiment, the capacitor may be formed by overlapping the first capacitor electrode and the second capacitor electrode, but the capacitor having a metal/dielectric/metal structure may be formed by forming an electrode on the same layer as that of the data line or the same layer as that of the first electrode. 
     In some embodiments, a second interlayer insulating layer  180  is formed on the data line  171 , the driving voltage line  172 , the first drain electrode  177   a  (not shown), and a first electrode  710 . 
     In some embodiments, the first electrode  710  and an auxiliary electrode  740  are formed on the second interlayer insulating layer  180 . 
     The first electrode  710  may be an anode of the organic light emitting element of  FIG. 1 . In some embodiments, the first electrode  710  is connected to the second drain electrode  177   b  through a contact hole  82 . 
     In an exemplary embodiment, the second drain electrode  177   b  and the first electrode  710  are connected through the contact hole  82  with the second interlayer insulating layer  180  interposed therebetween, but the second drain electrode  177   b  and the first electrode  710  may be integrally formed. 
     In some embodiments, the auxiliary electrode  740  is separated from the first electrode  710 , overlaps at least one of the data line  171  and the driving voltage line  172 , and is elongated along with them. In some embodiments, the auxiliary electrode  740  may be applied with the same voltage as a second electrode  730  to reduce the voltage drop of the second electrode  730 . 
     In some embodiments, an absorption electrode  770  is formed on the auxiliary electrode  740 . 
     In some embodiments, the auxiliary electrode  740  is generally connected to the second electrode  730 , and to connect the auxiliary electrode  740  and the second electrode  730  to each other, an organic emission layer  720  disposed between the auxiliary electrode  740  and the second electrode  730  must be removed. In this configuration, the organic emission layer  720  has the low energy absorbency and the energy transmission efficiency is largely decreased such that the absorption electrode  770  easily absorbs the energy by being disposed between the organic emission layer  720  and the auxiliary electrode  740 , and thereby the organic emission layer  720  may be further simply removed by a method of vaporizing the organic emission layer  720  by increasing the temperature of the organic emission layer  720 . 
     In some embodiments, the absorption electrode  770  absorbs the energy when removing the organic emission layer  720  such that a material for the absorption electrode  770  must have the high energy absorbency, and the absorption electrode  770  is disposed between the auxiliary electrode  740  and the second electrode  730  such that the material must have conductivity for an electrical connection between the auxiliary electrode  740  and the second electrode  730 . 
     Accordingly, the absorption electrode  770  may be a metal material having high absorbency and conductivity and may be formed of one selected from molybdenum (Mo), titanium (Ti), tungsten (W), and chromium (Cr). 
     In some embodiments, the absorption electrode  770  may be formed with a thickness of 300-1500 Å, and the energy absorbency is excellent in this range. 
     In some embodiments, the absorption electrode  770  may be formed of the single layer or the multiple layers. 
     When the absorption electrode  770  is formed of a plurality layers, an oxide layer (not shown) may be formed between a plurality of absorption electrodes  770 . 
     In some embodiments, the oxide layer may be one selected from ITO or IZO, and may have a thickness of 400-800 Å. 
     Among the absorption electrode  770  of the plurality of layers, a lower layer may be thicker than an upper layer, and the upper layer of a thickness of 40-100 Å and the lower layer of a thickness of 300-1000 Å may be formed. 
     In some embodiments, a pixel definition layer  116  patterned with an insulating material exposing at least a portion of the first electrode  710  and the auxiliary electrode  740  and the entire portion of the absorption electrode  770  is formed on the entire substrate including the first electrode  710 , and the organic emission layer  720  including an emission layer is formed on the pixel definition layer  116  formed on the entire substrate including the first electrode  710  and the exposed portion of the first electrode  710 . In some embodiments, the organic emission layer  720  includes a contact hole  74  exposing the auxiliary electrode  740  and the absorption electrode  770 . 
     As shown in the exemplary embodiment of  FIG. 2 , a plurality of contact holes  74  are disposed with a uniform interval, however it may be elongated along with the auxiliary electrode  740 . 
     In some embodiments, the organic emission layer  720  may be formed of a low molecular weight organic material or a high molecular weight organic material such as PEDOT ((poly)3,4-ethylenedioxythiophene). Further, the organic emission layer  720  may be formed of a multilayer including one or more of a hole injection layer (HIL), a hole transport layer (HTL), an electron transport layer (ETL), and an electron injection layer (EIL), and the emission layer. When all the layers are included, the hole injection layer (HIL) is disposed on the first electrode  710  as the anode, and the hole transport layer (HTL), the emission layer, the electron transport layer (ETL), and the electron injection layer (EIL) are sequentially laminated thereon. 
     In the organic emission layer  720 , a red organic emission layer, a green organic emission layer, and a blue organic emission layer may be laminated in a red pixel, a green pixel, and a blue pixel, respectively, and a red color filter, a green color filter, and a blue color filter may be formed for each pixel to embody a color image. As another example, a white organic emission layer emitting light having a white color may be formed in all of the red pixel, the green pixel, and the blue pixel, and the red color filter, the green color filter, and the blue color filter may be formed for each pixel to embody the color image. 
     For the organic emission layer  720  according to the present invention, the lamination structures of the red pixel, the blue pixel, and the green pixel are the same. Accordingly, a deposition mask for depositing the organic emission layer on each pixel, that is, the red pixel, the green pixel, and the blue pixel, may not be used. 
     The white organic emission layer described as another example may be formed of one organic emission layer, and even includes a constitution where a plurality of organic emission layers are laminated to emit light having the white color. For example, a constitution where at least one yellow organic emission layer and at least one blue organic emission layer are combined to emit light having the white color, a constitution where at least one cyan organic emission layer and at least one red organic emission layer are combined to emit light having the white color, or a constitution where at least one magenta organic emission layer and at least one green organic emission layer are combined to emit light having the white color may be included. 
     In some embodiments, the second electrode  730  is formed on an opening  99  exposing the organic emission layer  720  and the contact hole  74 . 
     In some embodiments, the second electrode  730  becomes a cathode of the organic light emitting element. Accordingly, the first electrode  710  and the absorption electrode  770 , the organic emission layer  720 , and the second electrode  730  form the organic light emitting element  70 . 
     In some embodiments, the second electrode  730  contacts an upper surface of the auxiliary electrode  740 , an upper surface and a side surface of the absorption electrode  770 , and an etched surface of the opening  99  in the contact hole  74 . 
     In some embodiments, the organic light emitting diode display may have any one structure among a top display type, a rear display type, and a both-side display type according to a direction in which the organic light emitting diode  70  emits light. 
     In the top display type of organic light emitting diode display according to the exemplary embodiment, the first electrode  710  is formed as a reflective layer, and the second electrode  730  is formed as a transparent layer or a semi-transparent layer. 
     In some embodiments, the reflective layer and the semi-transparent layer are formed of at least one metal among magnesium (Mg), silver (Ag), gold (Au), calcium (Ca), lithium (Li), chromium (Cr), and aluminum (Al), or an alloy thereof. The reflective layer and the semi-transparent layer are determined by thickness, and the semi-transparent layer may be formed to have a thickness equal to or less than 200 nm. As the thickness is decreased, transmittance of light is increased, but when the thickness is excessively small, resistance is increased. In some embodiments, the transparent layer may be formed of a material such as indium tin oxide (ITO), indium zinc oxide (IZO), zinc oxide (ZnO), or indium oxide (In 2 O 3 ). 
     As described above, when forming the auxiliary electrode  740  and the absorption electrode  770  that are connected to the second electrode  730 , the voltage drop of the driving voltage passing through the second electrode  730  that is formed on the entire substrate  100  may be minimized and the contact hole  74  may be simply formed. 
     An organic light emitting diode display according to another exemplary embodiment will be described with reference to  FIG. 4 . 
       FIG. 4  is a layout view of one pixel of an organic light emitting diode display according to another exemplary embodiment of the present invention. 
     The exemplary embodiment shown in  FIG. 4  is substantially the same as the exemplary embodiment shown in  FIG. 2  and  FIG. 3 , except for a formation position and a shape of the absorption electrode  770  such that the overlapping description of reference numerals is omitted. 
     As shown in the exemplary embodiment of  FIG. 4 , an absorption electrode  771  of the organic light emitting diode display does not have the line shape parallel to the auxiliary electrode  740 , but the absorption electrode  771  may be formed with a dot shape on the auxiliary electrode  740 . In  FIG. 4 , a plurality of absorption electrodes  771  have a quadrangle shape, however the shape of the absorption electrode may be various such as triangle or a polygon. 
     An organic light emitting diode display according to another exemplary embodiment will be described with reference to  FIG. 5  and  FIG. 6 . 
       FIG. 5  is a layout view of one pixel of an organic light emitting diode display according to the current exemplary embodiment of the present invention, and  FIG. 6  is a cross-sectional view taken along the line VI-VI of  FIG. 5 . 
     The exemplary embodiment shown in  FIG. 5  and  FIG. 6  is substantially the same as the exemplary embodiment shown in  FIG. 2  and  FIG. 3 , except that the auxiliary electrode  740  is replaced by the absorption electrode  770  such that the overlapping description of reference numerals is omitted. 
     In some embodiments, the absorption electrode  770  is separated from the first electrode  710 , overlaps at least one of the data line  171  and the driving voltage line  172 , and is elongated along with them. In some embodiments, the absorption electrode  770  with a function of the auxiliary electrode to reduce the voltage drop of the second electrode  730  may be applied with the same voltage as the second electrode  730 . 
     In some embodiments, the absorption electrode  740  is connected to the second electrode  730  to connect the absorption electrode  770  and the second electrode  730  to each other, the organic emission layer  720  disposed between the absorption electrode  770  and the second electrode  730  must be removed. In some embodiments, the organic emission layer  720  has the low energy absorbency and the energy transmission efficiency is largely decreased such that the absorption electrode  770  easily absorbs the energy by being disposed as the auxiliary electrode, and thereby the organic emission layer  720  may be further simply removed by the method of vaporizing the organic emission layer  720  by increasing the temperature of the organic emission layer  720 . 
     In some embodiments, the absorption electrode  770  absorbs the energy when removing the organic emission layer  720  such that the material for the absorption electrode  770  must have high energy absorbency, and the absorption electrode  770  has the function of the auxiliary electrode such that the material must have conductivity for an electrical connection between the absorption electrode  770  and the second electrode  730 . 
     Accordingly, the absorption electrode  770  may be the metal material having the high absorbency and the conductivity and may be formed of one selected from molybdenum (Mo), titanium (Ti), tungsten (W), and chromium (Cr). 
     In some embodiments, the absorption electrode  770  may be formed with a thickness of 300-1500 Å, and the energy absorbency is excellent in this range. 
     In some embodiments, the absorption electrode  770  may be formed of the single layer or the multiple layers. 
     In some embodiments, an oxide layer (not shown) may be formed between a plurality of absorption electrodes  770  when the absorption electrode  770  is formed of multiple layers. 
     In some embodiments, the oxide layer may be one selected from ITO or IZO, and may have a thickness of 400-800 Å. 
     In this configuration, among the absorption electrode  770  of the plurality of layers, a lower layer may be thicker than an upper layer, and the upper layer of a thickness of 40-100 Å and the lower layer of a thickness of 300-1000 Å may be formed. 
     In some embodiments, the organic emission layer  720  is formed on the entire substrate including the first electrode  710 . In some embodiments, the organic emission layer  720  includes the contact hole  74  exposing the absorption electrode  770  functioning as the auxiliary electrode. 
     Next, a method manufacturing the organic light emitting diode display will be described in detail with reference to  FIG. 7  to  FIG. 13  as well as  FIG. 2  and  FIG. 3 . 
       FIGS. 7 to 13  are cross-sectional views sequentially showing a manufacturing method of an organic light emitting diode display according to another exemplary embodiment of the present invention. 
     As shown in  FIG. 7 , the buffer layer  120  is formed on a substrate  100 . In some embodiments, the buffer layer  120  may be formed of a silicon nitride or a silicon oxide. 
     After forming a polysilicon film on the buffer layer  120 , the first semiconductor  135   a,  the second semiconductor  135   b,  and the first capacitor electrode  138  are formed by patterning the polysilicon film. 
     Next, as shown in  FIG. 8 , the gate insulating layer  140  may be formed on the first semiconductor  135   a  and the second semiconductor  135   b.  In some embodiments, the gate insulating layer  140  may be formed of a silicon nitride or a silicon oxide. 
     Furthermore, after stacking a metal film on the gate insulating layer  140 , the first and second gate electrodes  155   a  and  155   b  and the second capacitor electrode  158  are formed by patterning the metal film. 
     In some embodiments, the source region, the drain region, and the channel region may be formed by doping conductive impurities into the first semiconductor  135   a  and the second semiconductor  135   b  by using the first gate electrode  155   a  and the second gate electrode  155   b  as a mask. In some embodiments, prior to the formation of the first gate electrode  155   a  and the second gate electrode  155   b,  the conductive impurities can also be doped into the first capacitor electrode  138  using a photoresist film. Furthermore, if each of the first gate electrode  155   a  and the second gate electrode  155   b  is formed of a dual layer and the second capacitor electrode  158  is formed of a single layer, the conductive impurities can also be doped into the first capacitor electrode  138  along with the source region and the drain region. 
     As shown in  FIG. 9 , the interlayer insulating layer  160  having the contact holes  166  and  167  through which the source region and the drain region are respectively exposed is formed on the first and second gate electrodes  155   a  and  155   b  and the second capacitor electrode  158 . In some embodiments, the interlayer insulating layer  160  can be made of tetraethyl orthosilicate (TEOS), a silicon nitride, or a silicon oxide. Furthermore, the interlayer insulating layer  160  can be made of a low dielectric constant material in order to make the substrate flat. 
     Next, as shown in  FIG. 10 , ITO/Ag/ITO is deposited and patterned on the interlayer insulating layer  160  to form the first electrode  710  and the auxiliary electrode  740 . 
     Next, as shown in  FIG. 11 , the absorption electrode  770  is formed on the auxiliary electrode  740 . 
     In some embodiments, the absorption electrode  770  absorbs the energy when removing the organic emission layer  720  such that the material for the absorption electrode  770  must have the high energy absorbency, and the absorption electrode has the function of the auxiliary electrode  740  such that the material must have conductivity for the electrical connection between the absorption electrode  770  and the second electrode  730 . 
     Accordingly, the absorption electrode  770  may be the metal material having the high absorbency and the conductivity and may be formed of one selected from molybdenum (Mo), titanium (Ti), tungsten (W), and chromium (Cr). 
     In some embodiments, the absorption electrode  770  may be formed with a thickness of 300-1500 Å, and the energy absorbency is excellent in this range. 
     In some embodiments, the absorption electrode  770  may be formed of the single layer or the multiple layers. 
     When the absorption electrode  770  is formed of multiple layers, an oxide layer (not shown) may be formed between a plurality of absorption electrodes. 
     The oxide layer may be one selected from ITO or IZO, and may have a thickness of 400-800 Å. 
     In this configuration, among the absorption electrode  770  of the plurality of layers, a lower layer may be thicker than an upper layer, and the upper layer of the thickness of 40-100 Å and the lower layer of the thickness of 300-1000 Å may be formed. 
     In some embodiments, the absorption electrode  770  may be formed with the line shape parallel to the auxiliary electrode  740 , as shown in  FIG. 4 , may be formed with the dot shape on the auxiliary electrode  740 . 
     In some embodiments, the absorption electrode  770  absorbs the energy when removing the organic emission layer  720  such that the material for the absorption electrode  770  must have the high energy absorbency, and the absorption electrode  770  is disposed between the auxiliary electrode  740  and the second electrode  730  such that the material must have conductivity for an electric connection between the auxiliary electrode  740  and the second electrode  730 . 
     Accordingly, the absorption electrode  770  may be a metal material having high absorbency and conductivity and may be formed of one selected from molybdenum (Mo), titanium (Ti), tungsten (W), and chromium (Cr). 
     In some embodiments, the absorption electrode  770  may be formed with a thickness of 300-1500 Å, and the energy absorbency is excellent in this range. 
     In some embodiments, the absorption electrode  770  may be formed of the single layer or the multiple layers. 
     When the absorption electrode  770  is formed of multiple layers, an oxide layer (not shown) may be formed between a plurality of absorption electrodes  770 . 
     The oxide layer may be one selected from ITO or IZO, and may have a thickness of 400-800 Å. 
     At this time, among the absorption electrode  770  of the plurality of layers, the lower layer may be thicker than the upper layer, and the upper layer of the thickness of 40-100 Å and the lower layer of the thickness of 300-1000 Å may be formed. 
     Next, as shown in  FIG. 12 , on the first electrode  710 , the auxiliary electrode  740 , and the absorption electrode  770 , the pixel definition layer  116  patterned with the insulating material is formed to expose at least a portion of the first electrode  710  and the auxiliary electrode  740 , and the entire absorption electrode  770 , and the organic emission layer  720  is deposited on the pixel definition layer  116 , the exposed first electrode  710 , the auxiliary electrode  740 , and the absorption electrode  770 . 
     In some embodiments, the organic emission layer  720  is formed on the entire substrate without a separate mask, and a hole auxiliary layer, a red organic emission layer, a green organic emission layer, a blue organic emission layer, and an electron auxiliary layer may be sequentially deposited. 
     Next, a light source having energy having a wavelength region to be absorbed into the absorption electrode  770  to etch the organic emission layer  720 , and the second electrode  730  having the opening  99  exposing the auxiliary electrode  740  and the absorption electrode  770  and the contact hole  74 , are formed. 
     Conventionally, a laser is used when etching the organic emission layer  720 , however, when manufacturing the organic light emitting diode display according to an exemplary embodiment, the energy absorbency of the absorption electrode  770  is high such that a laser, a flash lamp, a tungsten halogen lamp, etc., may be used as an energy light source used to etch the organic emission layer  720 . 
     In some embodiments, the energy irradiated by the light source is easily absorbed to the absorption electrode  770  such that the temperature of the absorption electrode  770  is increased, and at this time, the organic emission layer  720  formed on the absorption electrode  770  may be etched by the method of increasing the temperature of the organic emission layer  720  and evaporating the organic emission layer  720 . 
     In some embodiments of the manufacturing of the organic light emitting diode display, the method of increasing the temperature of the organic emission layer  720  and evaporating the organic emission layer  720  by using the absorption electrode  770  is performed in the etching process to form the opening  99  in the organic emission layer  720  such that a patterning mask for the etching of the organic emission layer  720  may be omitted. 
     Next, as shown in  FIG. 13 , a metal layer is formed on the entire substrate to form the second electrode  730  on the organic emission layer  720  and connected to the auxiliary electrode  740  and the absorption electrode  770  exposed through the opening  99  of the organic emission layer  720 . 
     In some embodiments, the metal layer as the semi-transparent layer may be formed by depositing a Mg—Ag alloy. In some embodiments, the second electrode  730  is formed with a thickness of about 500 nm. 
     Exemplary Embodiment 1 :when forming an absorption electrode of a single layered structure, absorbency measuring according to wavelength 
     The energy absorbency of the light irradiated from the energy light source is measured when forming the absorption electrode of the single layer in the organic light emitting diode display according to an exemplary embodiment of the present invention. 
     In some embodiments, a flash lamp is used as the energy light source. 
     In some embodiments, the material of the absorption electrode is molybdenum (Mo), the absorbency is measured for the thicknesses 250 Å, 500 Å, 1000 Å, and 1500 Å of the absorption electrode, and a result thereof is shown in  FIG. 14 . 
     In the graph shown in  FIG. 14 , the horizontal axis represents a wavelength of the light source and the vertical axis represents the energy absorbency of the light source. As shown in  FIG. 14 , in the absorption electrode of the single layer, it may be confirmed that the absorbency of the light source energy is more than 50% in the thickness of the absorption electrode of more than 500 Å in the visible light region. 
     Exemplary Embodiment 2 :when forming an absorption electrode of a single layered structure, absorbency measuring according to wavelength 
     In the organic light emitting diode display according to another exemplary embodiment, the energy absorbency of the light irradiated from the energy light source is measured when forming the absorption electrode of the multiple layers. 
     In some embodiments, the energy light source uses the flash lamp. 
     In some embodiments, the material for the absorption electrode uses the dual layer of molybdenum (Mo), the thickness of the upper absorption electrode is 40 Å and 60 Å, and the thickness of the lower absorption electrode is 350 Å. The oxide layer between the upper and lower absorption electrodes uses ITO, and the thickness of the oxide layer is respectively 450 Å, 500 Å, 550 Å, 600 Å, and 700 Å to measure of the energy absorbency of the light source, and the result thereof is shown in  FIG. 15 . 
     In the graph shown in  FIG. 15 , the horizontal axis represents the wavelength of the light source and the vertical axis represents the energy absorbency of the light source. As shown in  FIG. 15 , in the absorption electrode of the multiple layers, it may be confirmed that the energy absorbency of the light source is more than 65% in the visible light region. 
     The organic light emitting diode (OLED) display according to an exemplary embodiment may minimize the voltage drop of the driving power passing through the large-sized electrode of the thin film for driving the organic emission layer, and may simplify the removal process of the organic emission layer on the auxiliary electrode by adding the absorption electrode on the auxiliary electrode. 
     While one or more embodiments of the present disclosure has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the embodiments are not limited to the disclosed exemplary embodiments and is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.