Patent Publication Number: US-2023147378-A1

Title: Display apparatus and method of manufacturing the same

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S) 
     This is a continuation application of U.S. patent application Ser. No. 17/177,363, filed Feb. 17, 2021 (now pending), the disclosure of which is incorporated herein by reference in its entirety. U.S. patent application Ser. No. 17/177,363 is a continuation application of U.S. patent application Ser. No. 16/580,042, filed Sep. 24, 2019, now U.S. Pat. No. 10,950,681, issued Mar. 16, 2021, the disclosure of which is incorporated herein by reference in its entirety. U.S. Pat. No. 10,950,681 claims priority benefit of Korean Patent Application 10-2018-0116876 under 35 U.S.C. §119, filed on Oct. 1, 2018 in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety for all purposes. 
    
    
     BACKGROUND 
     1. Field 
     Exemplary embodiments relate to a display apparatus and a method of manufacturing the display apparatus. 
     2. Description of the Related Art 
     Recently, a display apparatus having light weight and small size has been manufactured. A cathode ray tube (CRT) display apparatus has been used due to a performance and a competitive price. However, the CRT display apparatus has a weakness with a size or portability. Therefore, a display apparatus such as a plasma display apparatus, a liquid crystal display apparatus, or an organic light emitting display apparatus having small size, light weight and low-power-consumption is desirable. 
     SUMMARY 
     Embodiments are directed to a display apparatus, including a base substrate including a display area in which an image is displayed and a peripheral area adjacent to the display area, a source/drain pattern on the base substrate, the source/drain pattern including a connecting electrode in a pad portion of the peripheral area and a electrode of a thin film transistor in the display area, a planarization insulation layer on the base substrate, the planarization insulation layer contacting a side surface of the connecting electrode and a side surface of the electrode of the thin film transistor, and exposing a top surface of the connecting electrode, a connecting member contacting the connecting electrode, and a driving member including a driving circuit, the driving member being connected to the connecting member. 
     The connecting electrode may include a first layer pattern, and a second layer pattern on the first layer pattern. A constituent material of the first layer pattern and a constituent material of the second layer pattern may be different from each other. A top surface of the second layer may contact the connecting member. 
     The display apparatus may further include a via insulation layer on the planarization insulation layer and a first electrode on the via insulation layer, the first electrode being electrically connected to the thin film transistor. The first electrode may include silver (Ag). 
     A top surface of the connecting electrode has a smaller planar area than a bottom surface of the connecting electrode, so that the connecting electrode has a constant tapered cross-section. 
     The display apparatus may also include a via insulation layer on the planarization layer, a light emitting structure on the via insulation layer, the light emitting structure being electrically connected to the thin film transistor, a thin film transistor on the light emitting structure, and a touch structure directly on the thin film encapsulation layer. 
     The display apparatus may further include a stop layer pattern between the planarization insulation layer and the base substrate and between the planarization insulation layer and a side surface of the source/drain pattern. The stop layer pattern may include different materials from the planarization insulation layer. 
     The stop layer pattern may include silicon oxide (SiOx) or silicon nitride (SiNx). 
     The stop layer pattern may include an organic insulation material. 
     The source/drain pattern may be received in a recess on a top surface of the planarization insulation layer. The side surface and a bottom surface of the connecting electrode may contact the planarization insulation layer. 
     Embodiments are also directed to a method of manufacturing a display apparatus, including forming a source/drain pattern on a base substrate that includes a display area in which an image is to be displayed and a peripheral area adjacent to the display area, the source/drain pattern including a connecting electrode in a pad portion of the peripheral area and a electrode of a thin film transistor disposed in the display area, forming a preliminary insulation layer on the base substrate on which the source/drain pattern is formed, forming a planarization insulation layer that exposes a top surface of the connecting electrode by removing a portion of the insulation layer, and connecting the connecting electrode and a driving member that includes a driving circuit, using a connecting member between the connecting electrode and the driving member. 
     Forming the source/drain pattern may include sequentially forming a first layer and a second layer, the second layer being made of a material different from the first layer, and forming the source/drain pattern by etching the second layer and the first layer. 
     The method may further include forming a via insulation layer on the planarization layer and forming a first electrode including silver (Ag) on the via insulation layer. 
     Forming the planarization insulation layer may include removing a portion of the preliminary insulation layer located on the connecting electrode through a chemical mechanical planarization (CMP) process to expose a top surface of the connecting electrode. 
     The method may further include forming a stop layer on the source/drain pattern before forming the preliminary insulation layer. Forming the planarization insulation layer may include removing a portion of the preliminary insulation layer located on the connecting electrode through a chemical mechanical planarization (CMP) process to expose the stop layer; and removing a portion of the stop layer to expose a top surface of the connecting electrode. The stop layer may include a material having a lower CMP selectivity than the planarization insulation layer for the CMP process for the planarization insulation layer. 
     The stop layer may include silicon oxide (SiOx) or silicon nitride (SiNx). 
     The stop layer may include an organic insulation material. 
     The method may further include forming a via insulation layer on the planarization layer, forming a light emitting structure on the via insulation layer, forming a thin film encapsulation layer on the light emitting structure and directly forming a touch structure on the thin film encapsulation layer. 
     The method may further include forming a lower insulation layer on the base substrate before forming the source/drain pattern. The lower insulation layer and the preliminary insulation layer formed on the base substrate on which the source/drain pattern is formed may be formed of a same material. 
     The method may further include forming a via insulation layer on the planarization layer, forming a light emitting structure on the via insulation layer, forming a thin film encapsulation layer on the light emitting structure, and forming a touch structure directly on the thin film encapsulation layer. 
     The connecting member may include a conductive adhesive. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Features will become apparent to those of skill in the art by describing in detail exemplary embodiments with reference to the attached drawings in which: 
         FIG.  1    illustrates a plan view of a display apparatus according to an exemplary embodiment; 
         FIG.  2    illustrates a cross-sectional view taken along a line I-I′ of  FIG.  1   ; 
         FIG.  3    illustrates a partially enlarged sectional view of the display apparatus in which a pad portion of  FIG.  2    is enlarged; 
         FIG.  4    illustrates a cross-sectional view of a display apparatus according to an exemplary embodiment; 
         FIG.  5    illustrates a cross-sectional view of a display apparatus according to an exemplary embodiment; 
         FIG.  6    illustrates a partially enlarged sectional view of the display apparatus in which a pad portion of  FIG.  5    is enlarged; 
         FIG.  7    illustrates a cross-sectional view of a display apparatus according to an exemplary embodiment; 
         FIGS.  8 A to  8 F  illustrate cross-sectional views of stages of a method of manufacturing the display apparatus of  FIG.  2   ; 
         FIGS.  9 A to  9 G  illustrate cross-sectional views of stages a method of manufacturing the display apparatus of  FIG.  4   ; 
         FIGS.  10 A to  10 C  illustrate cross-sectional views of stages of a method of manufacturing the display apparatus of  FIG.  5   ; 
         FIGS.  11 A to  11 B  illustrate cross-sectional views of stages of a method of manufacturing the display apparatus of  FIG.  7   ; 
         FIG.  12    illustrates a block diagram of an electronic device according to example embodiments; 
         FIG.  13 A  illustrates an example wherein the electronic device of  FIG.  12    is implemented as a television; and 
         FIG.  13 B  illustrates an example wherein the electronic device of  FIG.  12    is implemented as a smart phone. 
     
    
    
     DETAILED DESCRIPTION 
     Example embodiments will now be described more fully hereinafter with reference to the accompanying drawings; however, they may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey exemplary implementations to those skilled in the art. 
     In the drawing figures, the dimensions of layers and regions may be exaggerated for clarity of illustration. It will also be understood that when a layer or element is referred to as being “on” another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may also be present. Further, it will be understood that when a layer is referred to as being “under” another layer, it can be directly under, and one or more intervening layers may also be present. In addition, it will also be understood that when a layer is referred to as being “between” two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present. Like reference numerals refer to like elements throughout. 
       FIG.  1    illustrates a plan view of a display apparatus according to an exemplary embodiment. 
     Referring to  FIG.  1   , the display apparatus may include a display area DA in which an image is displayed, and a peripheral area PA, which is a non-display area surrounding the display area DA. The display area DA may have a suitable shape such as polygonal, polygonal with rounded corners, elliptical, or circular, as examples. For example, as shown in  FIG.  1   , the display area DA may have a rectangular shape on a plane formed by a first direction D 1  and a second direction D 2  perpendicular to the first direction D 1 . 
     The peripheral area PA may include a left peripheral area adjacent to a left side of the display area DA, a right peripheral area adjacent to a right side of the display area DA, an upper peripheral area adjacent to an upper side of the display area DA and a lower peripheral area adjacent to a lower side of the display area DA. 
     A pad portion PAD may be formed in the lower peripheral area. A connecting electrode for connecting a driving member for driving the display apparatus may be disposed in the pad portion PAD. The connecting electrode may be a data pad, a gate pad, or the like to transmit a data signal, a scan signal, or the like. A portion of the peripheral area PA between the pad portion PAD and the display area DA may be formed with a bending area to allow the pad portion PAD to be located on a backside of the display area DA. 
     In the display area, a plurality of pixels for displaying an image, signal lines such as a scan line, a data line, and the like, may be disposed. Each of the pixels may include a light emitting structure and a pixel circuit including a thin film transistor, a storage capacitor, or the like. 
       FIG.  2    illustrates a cross-sectional view taken along a line I-I′ of  FIG.  1   . 
     Referring to  FIGS.  1  and  2   , the display apparatus may include a base substrate  100 , an active pattern ACT, a first insulation layer  110 , a gate pattern, a second insulation layer  120 , a source/drain pattern, a planarization insulation layer  130 , a via insulation layer  140 , a light emitting structure  180 , a pixel defining layer PDL, a thin film encapsulation layer TFE, and a connecting member CN. 
     The base substrate  100  may include a transparent insulating substrate. For example, the base substrate  100  may be a transparent resin substrate having flexibility. The transparent resin substrate may include a polyimide-based resin, an acryl-based resin, a polyacrylate-based resin, a polycarbonate-based resin, a polyether-based resin, a sulfonic acid-based resin, a polyethyleneterephthalate-based resin, or the like. For example, the base substrate  100  may be a polyimide (PI) resin film. 
     The active pattern ACT may be disposed on the base substrate  100 . The active pattern ACT may include amorphous silicon or polycrystalline silicon. In some example embodiment, the active pattern ACT may include an oxide of at least one substance selected from indium (In), gallium (Ga), tin (Sn), zirconium (Zr), vanadium (V), hafnium (Hf), cadmium (Cd), germanium (Ge), chromium (Cr), titanium (Ti), and zinc (Zn). The active pattern ACT may include a source region and a drain region doped with an impurity, and a channel region disposed between the source region and the drain region. 
     The display apparatus may further include a buffer layer disposed between the base substrate  100  and the active pattern ACT. 
     The buffer layer may help to prevent diffusion of metal atoms and/or impurities from the base substrate  100 . Additionally, the buffer layer may adjust a heat transfer rate of a successive crystallization process for the active pattern ACT, thereby obtaining a substantially uniform active pattern ACT. In the case that the base substrate  100  has a relatively irregular surface, the buffer layer may improve flatness of the surface of the base substrate  100 . The buffer layer may be formed using a silicon compound. For example, the buffer layer may include silicon oxide (SiOx), silicon nitride (SiNx), silicon oxynitride (SiOxNy), silicon oxycarbide (SiOxCy), silicon carbon nitride (SiCxNy), etc. 
     The first insulation layer  110  may be disposed on the base substrate  100  on which the active pattern ACT is disposed. The first insulation layer  110  may be uniformly formed on the base substrate  100  along a profile of the active pattern ACT. The first insulation layer  110  may include a silicon compound, metal oxide, etc. 
     The gate pattern may be disposed on the first insulation layer  110 . The gate pattern may include a gate electrode GE, a storage electrode, and a signal line such as a gate line. The gate pattern may be formed using metal, alloy, metal nitride, conductive metal oxide, transparent conductive material, etc. 
     The second insulation layer  120  may be disposed on the first insulation layer  110  on which the gate pattern is disposed. For example, the second insulation layer  120  may have a relatively large thickness for sufficiently covering the gate pattern, so that the second insulation layer  120  may have a substantially level surface. In some implementations, the second insulation layer  120  may be uniformly formed on the first insulation layer  110  along a profile of the gate pattern. The second insulation layer  120  may have a substantially smaller thickness along the profile of the gate pattern, such that a stepped portion may be formed at a portion of the second insulation layer  120  adjacent to the gate pattern. The second insulation layer  120  may include a silicon compound, a metal oxide, or the like. The second insulation layer  120  may be formed of a plurality of layers. 
     The source/drain pattern may be disposed on the second insulation layer  120 . The source/drain pattern may include a source electrode SE, a drain electrode DE and a signal line such as a data line disposed in the display area DA. The source/drain pattern may include a connecting electrode  122  disposed in the pad area PAD of the peripheral area PA. 
     The source/drain pattern may be formed using metal, alloy, metal nitride, conductive metal oxide, transparent conductive material, etc. The source/drain pattern may be formed of a plurality of layers. For example, the source/drain pattern may be a laminate structure including a first layer including titanium (Ti), a second layer including aluminum (Al), and a third layer including titanium (Ti). 
     The source electrode SE may be electrically connected to the source region of the active pattern ACT through a contact hole formed through the first insulation layer  110  and the second insulation layer  120 . The drain electrode DE may be electrically connected to the drain region of the active pattern ACT through a contact hole formed through the first insulation layer  110  and the second insulation layer  120 . 
     The active pattern ACT, the gate electrode GE, the source electrode SE, and the drain electrode DE may be included in a thin film transistor TFT as part of a pixel circuit. 
     The planarization insulation layer  130  may be disposed on the same layer as the source/drain pattern. For example, the planarization insulation layer  130  may be disposed on the second insulation layer  120  on which the source/drain pattern is disposed. The planarization insulation layer  130  may contact a side surface of the source/drain pattern without covering a top surface of the source/drain pattern. 
     The planarization insulation layer  130  may include an inorganic insulation material such as a silicon compound, a metal oxide, or an organic insulation material. 
     The via insulation layer  140  may be disposed on the source electrode SE, the drain electrode DE, and the planarization insulation layer  130  of the display area DA. The via insulation layer  140  may include an organic insulation material. The via insulation layer  140  may have a relatively large thickness for sufficiently covering the source/drain pattern, so that the via insulation layer  140  may be substantially level. 
     The via insulation layer  140  is not formed in a portion of the pad portion PAD adjacent to the connecting electrode  122 . Accordingly, a top surface of the connecting electrode  122  may be exposed. The top surface of the connecting electrode  122  may contact a connecting member CN, which will be described below. 
     The light emitting structure  180  may be disposed in the display area DA. The light emitting structure  180  may include a first electrode  181 , a light emitting layer  182  and a second electrode  183 . 
     The first electrode  181  may be disposed on the via insulation layer  140 . The first electrode  181  may be electrically connected to the thin film transistor TFT through a contact hole formed through the via insulation layer  140 . 
     The first electrode  181  may include a reflective material or a transmissive material in accordance with the emission type of the display apparatus. For example, the first electrode  181  may be formed using aluminum, an alloy containing aluminum, aluminum nitride, silver, an alloy containing silver, tungsten, tungsten nitride, copper, an alloy containing copper, nickel, an alloy containing nickel, chromium, chromium nitride, molybdenum, an alloy containing molybdenum, titanium, titanium nitride, platinum, tantalum, tantalum nitride, neodymium, scandium, strontium ruthenium oxide, zinc oxide, indium tin oxide, tin oxide, indium oxide, gallium oxide, indium zinc oxide, etc. These may be used alone or in a combination thereof. 
     In example embodiments, the first electrode  181  may have a single layer structure or a multi layer structure, which may include a metal film, an alloy film, a metal nitride film, a conductive metal oxide film and/or a transparent conductive film. 
     In some implementations, the first electrode  181  may have a laminated structure including a first layer including indium tin oxide (ITO), a second layer including silver (Ag), and a third layer including indium tin oxide (ITO). 
     The pixel defining layer PDL may be disposed on the via insulation layer  140  on which the first electrode  181  is disposed. The pixel defining layer PDL may be formed using an organic material. For example, the pixel defining layer PDL may include a photoresist, an acryl-based resin, a polyimide-based resin, a polyamide-based resin, a siloxane-based resin, etc. In some example embodiments, an opening that exposes the first electrode  181  may be formed by etching the pixel defining layer PDL. An emitting area and a non-emitting area of the display apparatus may be defined by the opening of the pixel defining layer PDL. For example, a portion where the opening of the pixel defining layer PDL is located may correspond to the emitting area, and a portion adjacent to the opening of the pixel defining layer PDL may correspond to the non-emitting area. 
     The light emitting layer  182  may be disposed on the first electrode  181  exposed through the opening of the pixel defining layer PDL. In some implementations, the light emitting layer  182  may extend on a sidewall of the opening of the pixel defining layer PDL. In some implementations, the light emitting layer  182  may include an organic light emitting layer (EL), a hole injection layer (HIL), a hole transfer layer (HTL), an electron transfer layer (ETL), an electron injection layer (EIL), etc. In some implementation, layers of the light emitting structure  180 , including the hole injection layer, the hole transport layer, the electron transport layer, and the electron injection layer, and excluding the organic emission layer, may be formed in common to correspond to a plurality of pixels. A plurality of organic light emitting layers may be formed using light emitting materials for generating different colors of light such as red light, green light and blue light in accordance with color pixels of the display device. In some example embodiments, the organic light emitting layer of the of the light emitting layer  182  may include a plurality of stacked light emitting materials for generating red light, green light and blue light to thereby emit white light. Elements of the light emitting layer  182  may be commonly formed so as to correspond to a plurality of pixels. Each pixel may be divided by a color filter layer. 
     The second electrode  183  may be disposed on the pixel defining layer PDL and the light emitting layer  182 . The second electrode  183  may include a transmissive material or a reflective material in accordance with the emission type of the display device. For example, the second electrode  183  may be formed using aluminum, an alloy containing aluminum, aluminum nitride, silver, an alloy containing silver, tungsten, tungsten nitride, copper, an alloy containing copper, nickel, an alloy containing nickel, chromium, chromium nitride, molybdenum, an alloy containing molybdenum, titanium, titanium nitride, platinum, tantalum, tantalum nitride, neodymium, scandium, strontium ruthenium oxide, zinc oxide, indium tin oxide, tin oxide, indium oxide, gallium oxide, indium zinc oxide, etc. These may be used alone or in a combination thereof. In example embodiments, the second electrode  183  may have a single layer structure or a multi layer structure, which may include a metal film, an alloy film, a metal nitride film, a conductive metal oxide film and/or a transparent conductive film. 
     The thin film encapsulation layer TFE may be disposed on the second electrode  183 . The thin film encapsulation layer TFE may help to prevent penetration of moisture and oxygen from outside. The thin film encapsulation layer TFE may include at least one organic layer and at least one inorganic layer. The at least one organic layer and the at least one inorganic layer may be alternately stacked. For example, the thin film encapsulation layer TFE may include two inorganic layers and one organic layer therebetween. In some implementations, a sealing substrate may be provided instead of the thin film encapsulation layer to prevent the penetration of moisture and oxygen from outside of the display apparatus. 
     A driving member DR may be electrically connected the connecting electrode  122  of the pad area PAD through the connecting member CN. A top surface of the connecting electrode  122  may be exposed and not covered by an insulation layer such as the via insulation layer  140 , the pixel defining layer PDL or the thin film encapsulation layer TFE. The connecting electrode  122  and the driving member DR may be electrically connected to each other by the connecting member CN. 
     The driving member DR may include a driving circuit or the like for generating a driving signal for driving the display apparatus. The driving member DR may include a printed circuit board, a flexible circuit board, an IC chip, or the like. The connecting member CN may include a conductive adhesive, for example, an ACF (anisotropic conductive film) or the like. 
       FIG.  3    illustrates a partially enlarged sectional view of the display apparatus in which a pad portion illustrated in  FIG.  2    is enlarged. 
     Referring to  FIGS.  2  and  3   , the connecting electrode  122  may include at least two or more layers including different materials. The connecting electrode  122  may include, for example, a first layer pattern  122   a,  a second layer pattern  122   b,  and a third layer pattern  122   c.    
     For example, as described above regarding the source/drain pattern, the first layer pattern  122   a  and the third layer pattern  122   c  may include titanium (Ti), and the second layer pattern  122   b  may include aluminum (Al). 
     The connecting electrode  122  may have a constant tapered cross-sectional shape along a third direction D 3  perpendicular to the first and second directions D 1  and D 2 . An angle θ between a bottom surface of the connecting electrode  122  and a side surface of the connecting electrode  122  may be an acute angle less than 90 degrees. 
     In addition, etch selectivity of the third layer pattern  122   c  including the top surface of the connecting electrode  122  in contact with the connecting member CN and the second layer pattern  122   b  under the same etching condition may be different from each other. That is, in an etching condition of the second layer pattern  122   b,  etch selectivity of the third layer pattern  122   c  may be lower than etch selectivity of the second layer pattern  122   b.  In addition, etch selectivity of the third layer pattern  122   c  may be lower than etch selectivity of the first electrode  181  under an etch condition of the first electrode  181 . 
     According to the present embodiment, the planarization insulation layer  130  is in contact with the side surface of the connecting electrode  122 . A separate insulation layer contacting the top surface of the connecting electrode  122  is not formed. Thus, the driving member DR may be easily connected or bonded to the connecting electrode  122  using the connecting member CN irrespective of a distance hl between the driving member DR and the connecting electrode  122 . 
       FIG.  4    illustrates a cross-sectional view of a display apparatus according to an exemplary embodiment. 
     Referring to  FIG.  4   , the display apparatus may be substantially the same as the display apparatus of  FIGS.  1  to  3    except for further including a stop layer pattern  125 . Therefore, an explanation of features that are the same as those of  FIGS.  1  to  3    will not be repeated. 
     The display apparatus may include a base substrate  100 , an active pattern ACT, a first insulation layer  110 , a gate pattern, a second insulation layer  120 , the stop layer pattern  125 , a source/drain pattern, a planarization insulation layer  130 , a via insulation layer  140 , a light emitting structure  180 , a pixel defining layer PDL, a thin film encapsulation layer TFE, and a connecting member CN. The gate pattern may include a gate electrode GE. The source/drain pattern may include source and drain electrodes SE and DE disposed in a display area DA and a connecting electrode  122  disposed in a pad portion PAD of the peripheral area PA. The active pattern ACT, the gate electrode GE, the source electrode SE, and the drain electrode DE may be included in a thin film transistor TFT constituting a pixel circuit. 
     The stop layer pattern  125  may be disposed between the second insulation layer  120  and the planarization insulation layer  130  and between the source/drain pattern and the planarization insulation layer  130 . For example, the stop layer pattern  125  may cover only a side surface of the source/drain pattern without covering a top surface of the source/drain pattern. 
     The stop layer pattern  125  may include different materials from the planarization insulation layer  130 . For example, the stop layer pattern  125  may include a material having a lower CMP (Chemical Mechanical Polishing) selectivity than the planarization insulation layer  130  for the CMP process for the planarization insulation layer  130 . 
     The stop layer pattern  125  may include an inorganic insulation material or an organic insulation material. For example, when the stop layer pattern  125  includes an inorganic insulation material, the stop layer pattern  125  may include silicon oxide (SiOx) or silicon nitride (SiNx). When the planarization insulation layer  130  includes silicon oxide (SiOx), the stop layer pattern  125  may include silicon nitride (SiNx). 
       FIG.  5    illustrates a cross-sectional view of a display apparatus according to an exemplary embodiment.  FIG.  6    illustrates a partially enlarged sectional view of the display apparatus in which a pad portion of  FIG.  5    is enlarged. 
     Referring to  FIGS.  5  and  6   , the display apparatus may be substantially the same as the display apparatus illustrated in  FIGS.  1  to  3   , except that a second insulation layer and a planarization insulation layer are formed as one planarization insulating layer  135 . Therefore, an explanation of features that are the same as those illustrated in  FIGS.  1  to  3    will not be repeated. 
     The display apparatus may include a base substrate  100 , an active pattern ACT, a first insulation layer  110 , a gate pattern, a planarization insulation layer  135 , a source/drain pattern, a via insulation layer  140 , a light emitting structure  180 , a pixel defining layer PDL, a thin film encapsulation layer TFE, a driving member DR and a connecting member CN. The gate pattern may include a gate electrode GE. The source/drain pattern may include source and drain electrodes SE and DE disposed in a display area DA and a connecting electrode  122  disposed in a pad portion PAD of the peripheral area PA. The active pattern ACT, the gate electrode GE, the source electrode SE, and the drain electrode DE may be included in a thin film transistor TFT constituting a pixel circuit. 
     A recess may be formed in the planarization insulation layer  135  to receive the source/drain pattern. The recess may have a shape recessed from the top surface of the planarization insulation layer  135  in a direction opposite to the third direction D 3 . The source/drain pattern may be received in the recess. 
     The planarization insulation layer  135  may include an inorganic insulating material such as a silicon compound or a metal oxide, or an organic insulating material. 
     Referring to  FIG.  6   , the connecting electrode  122  may include a first layer pattern  122   a , a second layer pattern  122   b,  and a third layer pattern  122   c.    
     The connecting electrode  122  may have a constant tapered cross-sectional shape along a third direction D 3  perpendicular to the first and second directions D 1  and D 2 . An angle between a bottom surface of the connecting electrode  122  and a side surface of the connecting electrode  122  may be an acute angle θ less than 90 degrees. 
       FIG.  7    illustrates a cross-sectional view of a display apparatus according to an exemplary embodiment. 
     Referring to  FIG.  7   , the display apparatus is substantially the same as the display apparatus of  FIGS.  1  to  3    except that it further includes a touch structure TS disposed on a thin film sealing layer TFE. Therefore, an explanation of features that are the same as those illustrated in  FIGS.  1  to  3    will not be repeated. 
     The display apparatus may include a base substrate  100 , an active pattern ACT, a first insulation layer  110 , a gate pattern, a second insulation layer  120 , a source/drain pattern, a planarization insulation layer  130 , a via insulation layer  140 , a light emitting structure  180 , a pixel defining layer PDL, a thin film encapsulation layer TFE, a touch structure TS, a driving member DR and a connecting member CN. The gate pattern may include a gate electrode GE. The source/drain pattern may include source and drain electrodes SE and DE disposed in a display area DA and a connecting electrode  122  disposed in a pad portion PAD of the peripheral area PA. The active pattern ACT, the gate electrode GE, the source electrode SE, and the drain electrode DE may be included in a thin film transistor TFT constituting a pixel circuit. 
     The touch structure TS may be formed directly on the thin film encapsulation layer TFE. The touch structure TS may include a first touch pattern TE 1 , an insulation layer  190 , and a second touch pattern TE 2 . The touch structure TS may be a suitable touch structure for touch recognition of a user. The touch structure TS may be formed directly on the thin film sealing layer TFE. In some implementations, the first and second touch patterns TE 1  and TE 2  may be formed as two layers with the insulation layer  190  interposed therebetween. In some implementations, the touch structure TS may be constituted by a touch pattern of one layer and an insulation layer. 
     According to the present embodiment, impurity formation due to an oxidation/reduction reaction in a process before forming the touch structure TS may be prevented. Accordingly, it may be possible to prevent defects such as a wiring short due to the impurities in the process of forming the touch structure TS. Thus, defects of the display apparatus can be reduced, the display quality can be improved, and process yield can be improved. 
       FIGS.  8 A to  8 F  illustrate cross-sectional views of stages of a method of manufacturing the display apparatus of  FIG.  2   . 
     Referring to  FIG.  8 A , an active pattern ACT may be formed on a base substrate  100 . A first insulation layer  110  may be formed on the base substrate  100  on which the active pattern ACT is formed. A gate pattern may be formed on the first insulation layer  110 . The gate pattern may include a gate electrode GE of a thin film transistor TFT. The second insulation layer  120  may be formed on the first insulation layer  110  on which the gate pattern is formed. Thereafter, a contact hole may be formed through the second insulation layer  120  to expose a portion of the active pattern ACT. 
     The second insulation layer  120  may be formed by a chemical vapor deposition process, a spin coating process, a plasma enhanced chemical vapor deposition process, a sputtering process, a vacuum deposition process, a high density plasma-chemical vapor deposition process, a printing process, or the like according to its constituent material. 
     A source/drain pattern may be formed on the second insulation layer  120 . The source/drain pattern may include a connecting electrode  122  disposed in a pad portion PAD of a peripheral area PA and source and drain electrodes SE and DE disposed in a display area DA. 
     The source/drain pattern may be obtained by forming a conductive layer on the second insulation layer  120  and then patterning the conductive layer using a photoetching process or an etching process using an additional etching mask. The conductive layer may be formed using a printing process, a sputtering process, a chemical vapor deposition process, a pulsed laser deposition (PLD) process, a vacuum deposition process, an atomic layer deposition (ALD) process, or the like. 
     The conductive layer may be formed of a plurality of layers including different constituent materials. For example, the conductive layer may include a first layer including titanium (Ti), a second layer including aluminum (Al), and a third layer including titanium (Ti). The first to third layers may be collectively etched and patterned. 
     Referring to  FIG.  8 B , a preliminary insulation layer  130   a  may be formed on the source/drain pattern and the second insulation layer  120 . The preliminary insulation layer  130   a  may be formed by a chemical vapor deposition process, a spin coating process, a plasma enhanced chemical vapor deposition process, a sputtering process, a vacuum deposition process, a high density plasma-chemical vapor deposition process, a printing process, or the like according to its constituent material. 
     Referring to  FIG.  8 C , a planarization insulation layer  130  may be formed to expose a top surface of the source/drain pattern by removing a portion of the insulation layer  130   a  where a step is formed by the source/drain pattern. 
     For example, a portion of the preliminary insulation layer  130   a  located above the connecting electrode  122  of the pad portion PAD of the peripheral area PA may be removed through a planarization process such as a chemical mechanical planarization (CMP) process or the like, so that the top surface of the connecting electrode  122  is exposed. A portion of the preliminary insulation layer  130   a  located on the source and drain electrodes SE and DE in the display area PA may be removed to expose the source and drain electrodes SE and DE. 
     Referring to  FIG.  8 D , a via insulation layer  140  may be formed on the planarization insulation layer  130  and on the source and drain electrodes SE and DE. A contact hole may be formed in the via insulation layer  140  to expose a portion of the drain electrode DE. The via insulation layer  140  may be formed by forming a photoresist layer on the planarization insulation layer  130 , followed by exposure and development. 
     A first electrode  181  may be formed on the via insulation layer  140 . The first electrode  181  may be obtained by forming a conductive layer on the via insulation layer  140  and then patterning the conductive layer using a photoetching process or an etching process using an additional etching mask. The conductive layer may be formed using a printing process, a sputtering process, a chemical vapor deposition process, a pulsed laser deposition (PLD) process, a vacuum deposition process, an atomic layer deposition (ALD) process, or the like. 
     The conductive layer may be formed of a plurality of layers including different constituent materials. For example, the conductive layer may include a first layer including indium tin oxide (ITO), a second layer including silver (Ag), and a third layer including indium tin oxide (ITO). The first to third layers may be collectively etched and patterned. 
     When the first electrode  181  is formed according to a general process, there is a risk that an etching process for patterning the first electrode  181  could affect a conductive pattern other than the first electrode  181 . For example, in a process of patterning the first electrode  181 , an impurity due to oxidation/reduction reaction could be formed on the surface of the connecting electrode  122 . When the first electrode  181  includes silver (Ag), silver particles could be deposited on the surface of the connecting electrode  122 . Further, it has been found through experiments that impurities could also be precipitated on the conductive pattern at a portion where an edge portion of the via insulation layer  140  is in contact with the conductive pattern. 
     The impurities such as silver particles could affect the patterning process of a subsequent conductive pattern, for example, a patterning process of the second electrode or the like, which could cause defects in the display apparatus, thereby deteriorating display quality and process yield. To address this issue, when the first electrode  181  is patterned according to the present embodiment, only the top surface (refer to  122   c  in  FIG.  3   ) of the third layer of the connecting electrode  122  is exposed. The third layer pattern  122   c  may be formed of titanium, which is less affected by the patterning of the first electrode  181 . The side surface of the connecting electrode, including the second layer pattern formed of aluminum (see  122   b  in  FIG.  3   )), which could be greatly affected by the patterning of the first electrode  181 , is covered by the planarization insulation layer  130  and not exposed. Thus, precipitation of impurities on the surface of the connecting electrode  122  can be minimized. 
     Accordingly, the impurities affecting the subsequent process may be minimized, the defects of the display apparatus may be reduced, the display quality may be improved, and the process yield may be improved. 
     Referring to  FIG.  8 E , a pixel defining layer PDL defining an opening may be formed on the via insulation layer  140  on which the first electrode  181  is formed. A light emitting layer  182  may be formed on the first electrode  181  in the opening of the pixel defining layer PDL. 
     A second electrode  183  may be formed on the light emitting layer  182 . The second electrode  182  may be formed by forming a conductive layer on the light emitting layer  183  and the pixel defining layer PDL and then patterning the conductive layer using a photoetching process or an etching process using an additional etching mask. The conductive layer may be formed using a printing process, a sputtering process, a chemical vapor deposition process, a pulsed laser deposition (PLD) process, a vacuum deposition process, an atomic layer deposition (ALD) process, or the like. 
     A thin film encapsulation layer TFE may be formed on the second electrode  183 . 
     Referring to  FIG.  8 F , by using a connecting member CN, a driving member DR may be connected to the connecting electrode  122  of the pad portion PAD. Accordingly, the display apparatus may be manufactured. The connecting member CN may include a conductive adhesive, for example, an ACF (anisotropic conductive film) or the like. 
     The top surface of the connecting electrode  122  may be on a same level as a top surface of the planarization insulation layer  130  adjacent to the connecting electrode  122 . Accordingly, the driving member DR may be easily connected to the display apparatus using the connecting member CN. 
       FIGS.  9 A to  9 G  illustrate cross-sectional views of stages of a method of manufacturing the display apparatus illustrated in  FIG.  4   . The method is substantially the same as the method of  FIGS.  8 A to  8 F , except for forming a stop layer  125   a  and a stop layer pattern  125 . Therefore, an explanation of stages that are the same as those illustrated in  FIGS.  8 A to  8 F  will not be repeated. 
     Referring to  FIG.  9 A , an active pattern ACT, a first insulation layer  110 , a gate pattern including a gate electrode GE, and a second insulation layer  120  may be formed on a base substrate  100 . 
     A source/drain pattern may be formed on the second insulation layer  120 . The source/drain pattern may include a connecting electrode  122  in the pad portion PAD of the peripheral area PA and source and drain electrodes SE and DE in the display area DA. 
     Referring to  FIG.  9 B , a stop layer  125   a  and a preliminary insulation layer  130   a  may be sequentially formed on the source/drain pattern and the second insulation layer  120 . 
     The stop layer  125   a  and the preliminary insulation layer  130   a  may be formed by a chemical vapor deposition process, a spin coating process, a plasma enhanced chemical vapor deposition process, a sputtering process, a vacuum deposition process, a high density plasma-chemical vapor deposition process, a printing process, or the like according to its constituent material. 
     Referring to  FIG.  9 C , a portion of the preliminary insulation layer  130   a  where a step is formed by the source/drain pattern may be removed to expose a portion of the stop layer  125   a  on the source/drain pattern. 
     For example, the portion of the preliminary insulation layer  130   a  on the connecting electrode  122  in the pad portion PAD of the peripheral area PA may be removed through a planarization process such as a chemical mechanical planarization (CMP) process or the like. A part of the preliminary insulation layer  130   a  located on the source and drain electrodes SE and DE in the display area PA may also be removed. 
     Here, the stop layer  125   a  may include a material having a lower CMP selectivity than the preliminary insulation layer  130   a  in the CMP process for the preliminary insulation layer  130   a.  For example, in the CMP process for removing the portion of the preliminary insulation layer  130   a,  the stop layer  125   a  may be left without being removed. For example, when the preliminary insulation layer  130   a  includes silicon oxide (SiOx), the stop layer  125   a  may include silicon nitride (SiNx). Accordingly, the stop layer  125   a  on the preliminary insulation layer  130   a  may not be removed by the CMP process, and the CMP process for removing the preliminary insulation layer  130   a  may be performed until the stop layer  125   a  is exposed. 
     The stop layer  125   a  may include an inorganic insulating material or an organic insulating material. For example, when the stop layer  125   a  includes an inorganic insulating material, the stop layer  125   a  may include silicon oxide (SiOx) or silicon nitride (SiNx). 
     Referring to  FIG.  9 D , a portion of the stop layer  125   a  exposed by the planarization insulation layer  130  may be removed to expose the connecting electrode  122  and the source and drain electrodes SE and DE. This may be accomplished through additional processes, such as a separate polishing process, to form a stop layer pattern  125  that exposes the connecting electrode  122 . 
     According to the present embodiment, the CMP process for forming the planarization insulation layer  130  may be performed while the top surface of the connecting electrode  122  is covered by the stop layer  125   a.  A portion of the stop layer  125   a  is removed through a separate process, so that the damage to the connecting electrode  122  by the CMP process on the preliminary insulation layer  130   a  can be reduced or prevented. 
     Referring to  FIG.  9 E , a via insulation layer  140  may be formed on the planarization insulation layer  130  and the source and drain electrodes SE and DE. Thereafter, a first electrode  181  may be formed on the via insulation layer  140 . 
     Referring to  FIG.  9 F , a pixel defining layer PDL defining an opening may be formed on the via insulation layer  140  on which the first electrode  181  is formed. A light emitting layer  182  may be formed on the first electrode  181  in the opening of the pixel defining layer PDL. A second electrode  183  may be formed on the light emitting layer  182 . A thin film encapsulation layer TFE may be formed on the second electrode  183 . 
     Referring to  FIG.  9 G , by using a connecting member CN, a driving member DR may be connected to the connecting electrode  122  of the pad portion PAD. Accordingly, the display apparatus may be manufactured. 
       FIGS.  10 A to  10 G  are cross-sectional views illustrating stages of a method of manufacturing the display apparatus of  FIG.  5   . The method is substantially the same as the method of  FIGS.  8 A to  8 E , except for a planarization insulation layer  135 . Therefore, an explanation of stages that are the same as those described above will not be repeated. 
     Referring to  FIG.  10 A , an active pattern ACT, a first insulation layer  110 , a gate pattern including a gate electrode GE may be formed on a base substrate  100 . A lower insulating layer  135   a  may be formed on the first insulating layer  110  on which the gate pattern is formed. 
     After a contact hole is formed through the lower insulating layer  135   a,  a source/drain pattern including source and drain electrodes SE and DE may be formed on the lower insulating layer  135   a.    
     Referring to  FIG.  10 B , an upper insulation layer  135   b  may be formed on the lower insulation layer  135   a  on which the source/drain pattern is formed. The upper insulation layer  135   b  may be formed of the same material as the lower insulation layer  135   a.    
     Referring to  FIG.  10 C , a planarization insulation layer  130  may be formed to expose a top surface of the source/drain pattern by removing a portion of the upper insulation layer  135   b  in which the step is formed by the source/drain pattern. 
     For example, the upper portion of the preliminary insulation layer  130   a  located above the connecting electrode  122  of the pad portion PAD of the peripheral area PA may be removed through a planarization process such as a chemical mechanical planarization (CMP) process or the like, so that the top surface of the connecting electrode  122  may be exposed. In addition, a portion of the upper insulating layer  135   b  located on the source and drain electrodes SE and DE in the display area PA may be removed to expose the source and drain electrodes SE and DE. 
     Thereafter, the display apparatus can be manufactured through the same method as the manufacturing method shown in  FIGS.  8 D to  8 F . 
       FIGS.  11 A to  11 B  are cross-sectional views illustrating stages a method of manufacturing the display apparatus of  FIG.  7   . The method is substantially the same as the method of  FIGS.  8 A to  8 F , except for further forming a touch structure TS on a thin film encapsulation layer TFE. Therefore, an explanation of stages described above will not be repeated. 
     Referring to  FIG.  11 A , an active pattern ACT, a first insulation layer  110 , a gate pattern including a gate electrode GE, and a second insulation layer  120 , a source/drain pattern comprising source and drain electrodes SE and DE and a connecting electrode  122 , a planarization insulation layer  130 , a via insulation layer  140 , a light emitting structure  180 , a pixel defining layer PDL, and a thin film transistor TFE may be formed on a base substrate  100 . 
     The touch structure TS may be formed on the thin film encapsulation layer TFE. For example, the touch structure TS may be formed by forming a first touch electrode TE 1 , an insulating layer  190  and a second touch electrode TE 2  on the thin film encapsulation layer TFE. 
     Impurity formation due to oxidation/reduction reaction in a forming process of the first electrode  181  may be reduced or prevented, and defects such as a wiring short due to the impurities in the process of forming the touch structure TS may be reduced or prevented as described above. Thus, defects of the display apparatus can be reduced, the display quality can be improved, and process yield can be improved. 
     Referring to  FIG.  11 B , by using a connecting member CN, a driving member DR may be connected to the connecting electrode  122  of the pad portion PAD. Accordingly, the display apparatus may be manufactured. 
     According to the exemplary embodiments, a method of manufacturing a display apparatus includes forming a source/drain pattern on a base substrate which includes a display area in which an image is displayed and a peripheral area adjacent to the display area, the source/drain pattern including a connecting electrode in a pad portion of the peripheral area and a electrode of a thin film transistor disposed in the display area, forming an insulation layer on the base substrate on which the source/drain pattern is formed, forming a planarization insulation layer which exposes a top surface of the connecting electrode by removing a portion of the insulation layer, and connecting the connecting electrode and a driving member which includes a driving circuit using a connecting member between the connecting electrode and the driving member. At this time, it is possible to minimize precipitation of impurities on a surface of the connecting electrode during the manufacturing process, thereby reducing defects due to the impurities in a subsequent process. 
       FIG.  12    is a block diagram illustrating an electronic device according to example embodiments.  FIG.  13 A  is a diagram illustrating an example in which the electronic device of 
       FIG.  12    is implemented as a television.  FIG.  13 B  is a diagram illustrating an example in which the electronic device of  FIG.  12    is implemented as a smart phone. 
     Referring to  FIGS.  12  through  13 B , the electronic device  500  may include a processor  510 , a memory device  520 , a storage device  530 , an input/output (I/O) device  540 , a power supply  550 , and a display device  560 . The display device  560  may correspond to the display apparatus of  FIG.  1   . The electronic device  500  may further include a plurality of ports for communicating with a video card, a sound card, a memory card, a universal serial bus (USB) device, other electronic devices, etc. The electronic device  500  may be implemented as a cellular phone, a video phone, a smart pad, a smart watch, a tablet PC, a car navigation system, a computer monitor, a laptop, a head mounted display (HMD), etc. As mentioned above, the electronic device  500  may be implemented as a television or as a smart phone as illustrated in  FIGS.  13 A and  13 B . 
     Referring again to  FIG.  12   , the processor  510  may perform various computing functions. The processor  510  may be a micro processor, a central processing unit (CPU), an application processor (AP), etc. The processor  510  may be coupled to other components via an address bus, a control bus, a data bus, etc. The processor  510  may be coupled to an extended bus such as a peripheral component interconnection (PCI) bus. The memory device  520  may store data for operations of the electronic device  500 . For example, the memory device  520  may include at least one non-volatile memory device such as an erasable programmable read-only memory (EPROM) device, an electrically erasable programmable read-only memory (EEPROM) device, a flash memory device, a phase change random access memory (PRAM) device, a resistance random access memory (RRAM) device, a nano floating gate memory (NFGM) device, a polymer random access memory (PoRAM) device, a magnetic random access memory (MRAM) device, a ferroelectric random access memory (FRAM) device, etc, and/or at least one volatile memory device such as a dynamic random access memory (DRAM) device, a static random access memory (SRAM) device, a mobile DRAM device, etc. The storage device  530  may include a solid state drive (SSD) device, a hard disk drive (HDD) device, a CD-ROM device, etc. The I/O device  540  may include an input device such as a keyboard, a keypad, a mouse device, a touchpad, a touch-screen, etc., or an output device such as a printer, a speaker, etc. The power supply  550  may provide power for operations of the electronic device  500 . 
     The display device  560  may be coupled to other components via the buses or other communication links. In some example embodiments, the display device  560  may be included in the I/O device  540 . As described above, the display device  560  may include a planarization insulation layer. 
     By way of summation and review, various efforts have been made to improve process yield of a manufacturing process or to improve display quality of a display apparatus by changing the manufacturing process or a layered structure of the display apparatus. Embodiments provide a display apparatus capable of improving display quality. Embodiments further provide a method of manufacturing the display apparatus capable of improving process yield. In a manufacturing process, a side surface of a connecting electrode may be covered to minimize the precipitation of impurities on a surface of the connecting electrode. Defects in the manufacturing process can be reduced, and a driving member can be easily connected to the connecting electrode using a connecting member. 
     Embodiments of the display apparatus and method of manufacturing the display apparatus as disclosed herein may be applied to a display device and various electronic devices including the same. For example, embodiments may be applied to a mobile phone, a smart phone, a video phone, a smart pad, a smart watch, a tablet PC, a car navigation system, a television, a computer monitor, a notebook, etc. 
     Example embodiments have been disclosed herein, and although specific terms are employed, they are used and are to be interpreted in a generic and descriptive sense only and not for purpose of limitation. In some instances, as would be apparent to one of ordinary skill in the art as of the filing of the present application, features, characteristics, and/or elements described in connection with a particular embodiment may be used singly or in combination with features, characteristics, and/or elements described in connection with other embodiments unless otherwise specifically indicated. Accordingly, it will be understood by those of skill in the art that various changes in form and details may be made without departing from the spirit and scope thereof as set forth in the following claims.