Patent Publication Number: US-2019181161-A1

Title: Array substrate and preparation method therefor, and display device

Description:
CROSS REFERENCE 
     The present application is based upon International Application No. PCT/CN2018/086843, filed on May 15, 2018, which is based upon and claims priority to Chinese Patent Application No. 201710401601.7, filed on May 31, 2017, and the entire contents thereof are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to the technical field of display technology, and in particular, to an array substrate, a manufacturing method thereof and a display device. 
     BACKGROUND 
     To manufacture an array substrate, copper is generally used as a material of a source/drain metal layer including a source electrode, a drain electrode, and a data line in the array substrate. Since the property of copper is relatively active, and the copper is prone to diffuse into other films or layers, and under the action of high temperature or an applied electric field, copper is prone to be oxidized, it may affect the display effect of the display device including the array substrate. Therefore, the material constituting the source/drain metal layer generally further includes molybdenum-niobium (chemical formula: MoNb), and a molybdenum-niobium layer is usually formed on the upper and lower surfaces of the copper metal layer to protect the copper. 
     It should be noted that the information disclosed in the background section above is only for enhancing the understanding of the background of the present disclosure, and thus may include information that does not constitute prior art known to those of ordinary skill in the art. 
     SUMMARY 
     Arrangements of the present disclosure provide an array substrate, a manufacturing method thereof, and a display device. 
     In one aspect of the arrangements of the present disclosure, there is provided a manufacturing method for an array substrate. The manufacturing method includes forming a first conductive film on a substrate. The manufacturing method includes patterning the first conductive film to form a first conductive layer formed of a conductive pattern. The first conductive layer includes a first signal line. The manufacturing method includes forming a second conductive film on the first conductive layer and patterning the second conductive film to form a second conductive layer formed of a conductive pattern. The second conductive layer includes a second signal line. The first signal line and the second signal line intersect with each other and are insulated from each other. In a portion of an upper surface of the first signal line which overlaps with the second signal line. A length of an edge extending in a direction along with the second signal line is larger than a linear distance between two vertices of the edge. 
     In some arrangements, a width of the second signal line in an overlapping region of orthogonal projections of the second signal line and the first signal line on the substrate is greater than a width of the second signal line in a non-overlapping region of the orthogonal projections of the second signal line and the first signal line on the substrate. 
     In some arrangements, the manufacturing method further includes roughening the second conductive film. 
     In some arrangements, roughening the second conductive film includes coating a surface of the second conductive film with a photoresist, pre-baking, exposing, developing, and post-baking the photoresist, and removing the photoresist. 
     In another aspect of the arrangements of the present disclosure, there is provided an array substrate. The array substrate includes a substrate, and a first signal line and a second signal line disposed in sequence on the substrate. The first signal line and the second signal line intersect with each other and are insulated from each other. In a portion of an upper surface of the first signal line which overlaps with the second signal line, a length of an edge extending in a direction of the second signal line is greater than a linear distance between two vertices of the edge. 
     In some arrangements, in the portion of the upper surface of the first signal line which overlaps with the second signal line, two edges along the direction of the second signal line are all arc lines. 
     In some arrangements, a width of the second signal line in an overlapping region of orthogonal projections of the second signal line and the first signal line on the substrate is greater than a width of the second signal line in a non-overlapping region of the orthogonal projections of the second signal line and the first signal line on the substrate. 
     In some arrangements, the first signal line is a gate line and/or a common line, and the second signal line is a data line. In some arrangements, the first signal line is a data line, and the second signal line is a gate line and/or a common line. 
     In some arrangements, the second signal line includes a first copper diffusion barrier layer, a copper/copper alloy layer, and a second copper diffusion barrier layer disposed in sequence. 
     In still another aspect of the arrangements of the present disclosure, there is provided a display device including any of the array substrate described above. 
     The arrangements of the present disclosure provide an array substrate, a manufacturing method thereof, and a display device. The manufacturing method for the array substrate includes forming a first conductive film on a substrate, and patterning the first conductive film to form a first conductive layer formed of a conductive pattern. The first conductive layer includes a first signal line. The manufacturing method includes forming a second conductive film on the first conductive layer, and patterning the second conductive film to form a second conductive layer formed of a conductive pattern. The second conductive layer includes a second signal line. The first signal line and the second signal line intersect with each other and are insulated from each other. 
     In a portion of an upper surface of the first signal line which overlaps with the second signal line, a length of an edge extending in a direction along with the second signal line is greater than a linear distance between two vertices of the edge. 
     It should be understood that the above general description and the following detailed description are merely exemplary and explanatory, and are not limiting of the present disclosure. 
     This section provides an overview of various implementations or examples of the techniques described in the present disclosure, and is not a comprehensive disclosure of the full scope or all features of the disclosed technology. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order to more clearly illustrate the arrangements of the present disclosure or the technical solutions in the related art, the drawings used in the arrangements or the description of the related art will be briefly described below. Apparently, the drawings in the following description only illustrate some arrangements of the present disclosure, and other drawings can be obtained from these drawings by those skilled in the art without any creative effort. 
         FIG. 1  is a flowchart of a method for manufacturing an array substrate according to an arrangement of the present disclosure; 
         FIG. 2  is a schematic structural diagram of an array substrate manufactured according to the manufacturing method shown in  FIG. 1 ; 
         FIG. 3  is a schematic structural diagram of an array substrate according to an arrangement of the present disclosure; 
         FIG. 4  is an enlarged view of an area A in the array substrate shown in  FIG. 3 ; 
         FIG. 5  is a schematic structural diagram of a first signal line and a second signal line in the array substrate shown in  FIG. 3 ; 
         FIG. 6  is another schematic structural diagram of a first signal line and a second signal line in the array substrate shown in  FIG. 3 ; 
         FIG. 7  is another schematic structural diagram of a first signal line and a second signal line in the array substrate shown in  FIG. 3 ; and 
         FIGS. 8( a )-8( f )  are schematic diagrams showing a process of manufacturing an array substrate according to an arrangement of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The technical solutions in the arrangements of the present disclosure are clearly and completely described in the following with reference to the accompanying drawings in the arrangements of the present disclosure. Apparently, the described arrangements are only a part of the arrangements of the present disclosure, but not all of the arrangements. All other arrangements obtained by those skilled in the art based on the arrangements of the present disclosure without creative efforts fall within the scope of the present disclosure. 
     An arrangement of the present disclosure provides a method for manufacturing an array substrate. As shown in  FIG. 1 , the method includes the following blocks. 
     In block S 101 , a first conductive film is formed on the substrate  10 , and the first conductive film is patterned to form a first conductive layer  11  formed of a conductive pattern, as shown in  FIG. 2 . Referring to  FIG. 3 , the first conductive layer  11  includes a first signal line  111 . 
     It should be noted that the patterning may refer to a process including a photolithography process, or including a photolithography process and an etching operation to form a predetermined pattern. The photolithography process includes a process of forming a film, exposing, developing, etc., and specifically, a process of forming a pattern by using a photoresist, a mask, an exposure machine, or the like. 
     In block S 102 , a second conductive film is formed on the first conductive layer  11 , and the second conductive film is patterned to form a second conductive layer  12  formed of a conductive pattern, as shown in  FIG. 2 . Referring again to  FIG. 3 , the second conductive layer  12  includes a second signal line  121 , and the first signal line  111  and the second signal line  121  are disposed as intersecting with each other and being insulated from each other. 
     As shown in  FIG. 4 , in the portion of the upper surface of the first signal line  111  which overlaps with the second signal line  121 , a length of at least one edge E in the extending direction of the second signal line  121  is larger than a linear distance J between the two vertices of the edge. The extending direction of the second signal line  121  is the Y direction in  FIG. 3 . That is, the edge E being an edge positioned in the Y direction with respect to other edges of the overlapped portion. In other words, an overlapping pattern, or an overlapping region, OP is formed by orthogonal projections of the second signal line  121  and the first signal line  111  on the substrate, a length of at least one edge of the overlapping pattern OP in an extending direction of the second signal line is larger than a linear distance between two vertices of the edge. 
     It should be noted that, first, the shape of the mask can be controlled to have a specific pattern the same as the shape of the first signal line  111  desired to be formed, so that after exposure is performed with the mask and the subsequent photolithography process is performed, the formed first signal line  111  may have the desired feature. 
     Second, after the first signal line  111  is formed, an insulating layer may be formed on the surface of the first conductive layer  11 , and then the second conductive layer  12  is formed on the surface of the insulating layer, so that the formed first signal line  111  and the second signal line  121  may be disposed intersecting each other and insulated from each other, and the second signal line  121  is located above the first signal line  111 . 
     Third, patterning the second conductive film to form a second conductive layer  12  formed of a conductive pattern may specifically include: coating a photoresist on the surface of the second conductive film, and forming the second conductive layer  12  through processes of exposing, developing, and etching. 
     Based on this, the present disclosure provides a method for manufacturing an array substrate. Specifically, a first conductive film is formed on the substrate  10 , and the first conductive film is patterned to form a first conductive layer  11  formed of a conductive pattern, the first conductive layer  11  including a first signal line  111 . A second conductive film is formed on the first conductive layer  11 , and the second conductive film is patterned to form a second conductive layer  12  formed of a conductive pattern, the second conductive layer  12  including a second signal line  121 , the first signal line  111  and the second signal line  121  are disposed intersecting each other and insulated from each other. 
     In the portion of the upper surface of the first signal line  111  which overlaps with the second signal line  121 , a length of at least one edge E in the extending direction of the second signal line  121  is larger than a linear distance J between the two vertices of the edge E. Assuming that the thickness of the first signal line  111  is constant, the contact area of the second conductive film with the first conductive layer  11  at the climbing area will be increased, compared to the case where the edge E has a length equal to the linear distance between the two vertices of the edge E. In this way, when photoresist is formed on the surface of the second conductive film, the photoresist can have an increased contact area with the second conductive film at the climbing area, which can reduce the chance of generating voids in the photoresist at the climbing area. In turn, during the etching process, it can reduce the chance of the etching liquid intruding into the second conductive film through the voids and causing the second signal line  121  to be broken. 
     Further, the present disclosure does not limit the shape of the edge E as long as the length of the edge E is larger than the linear distance J between the two vertices of the edge E. For example, the edge E may be as shown in  FIG. 4 , at least one edge E may be an arc line; or the edge E may be a polygonal line. 
     Taking the edge E as an arc line as an example, when forming the second signal line  121  by the patterning process, in order to increase the contact area of the photoresist with the second conductive film at the climbing area, optionally, in the portion of the upper surface of the first signal line  111  which overlaps with the second signal line  121 , two edges E in the extending direction of the second signal line  121  are all arc lines. As shown in  FIG. 5 , the arc lines of the two edges E have the same protrusion direction. However, the arc lines of the two edges E may have different protrusion directions. Considering that the thinness of the signal line is generally small, when the arc lines of the two edges E have protrusion directions pointing to each other, the portion of the upper surface of the first signal line  111  which overlaps with the second signal line  121  may have a smaller width, and the first signal line  111  may be easily broken. Therefore, when the first signal line  111  is relatively thin, optionally, in the portion of the upper surface of the first signal line  111  which overlaps with the second signal line  121 , the two edges E along the extending direction of the second signal line  121  may be arc lines having the same protrusion direction, or having protrusion directions pointing away from each other. 
     In order to simplify the process when fabricating the array substrate, sometimes a portion of the gate line serves as the gate electrode. For example, as shown in  FIG. 7 , the first signal line  111  is a gate line, and the second signal line  121  is a data line. The first signal line  111  includes a convex portion B and a gate line body C. The second signal line  121  overlaps with the convex portion B, and the drain electrode  13  overlaps with the convex portion B. In this case, since the first signal line  111  is relatively thick, even if in the portion of the upper surface of the first signal line  111  which overlaps with the second signal line  121 , the two edges E along the extending direction of the second signal line  121  are arc lines having protrusion directions pointing to each other, the portion of the upper surface of the first signal line  111  which overlaps with the second signal line  121  may still have a relatively large width, and thus the chance of broken line can be reduced. 
     On the basis of this, in order to further increase the contact area of the photoresist with the second conductive film at the climbing area, optionally, as shown in  FIG. 5 , a width W 2  of the second signal line  121  in an overlapping region of orthogonal projections of the second signal line  121  and the first signal line  111  on the substrate  10  is larger than a width W 1  of the second signal line  121  in a non-overlapping region of the orthogonal projections of the second signal line  121  and the first signal line  111  on the substrate  10 . The width of the second signal line  121  refers to a linear distance from one side of the second signal line  121  to the other side of the second signal line  121  along the extending direction of the first signal line  111  (i.e. the X direction shown in  FIG. 3 ). 
     It should be noted that, firstly, the shape of the mask can be controlled to have a specific pattern the same as the shape of the second signal line  121  desired to be formed, so that after exposure is performed with the mask and the subsequent photolithography process is performed, the formed second signal line  121  may have the desired feature. 
     In this case, when a photoresist is formed on the surface of the second conductive film, at the climbing area, compared to the case where W 1 =W 2  in the second signal line  121 , the photoresist and the upper surface of the second conductive film can have a further increased contact area, so that the chance of generation of voids in the photoresist at the climbing area can be further reduced. 
     On the basis of this, the present disclosure does not limit the type of the array substrate. For the signal lines that are arranged intersecting each other in the array substrate, at the overlapping area of the two signal lines, when the signal line at the bottom layer is configured in the above described structure, it can reduce the chance of breaking for the signal line at the top player during fabrication of the signal line. For example, when the array substrate is of a bottom gate type, as shown in  FIG. 3 , the first signal line  111  may be a gate line or a common line (Gate Common) in the same layer as the gate line, and the second signal line  121  is a data line (SD Line). When the array substrate is of the top gate type, the first signal line  111  is a data line, and the second signal line  121  is a gate line or a common line in the same layer as the gate line. 
     Further, the first signal line  111  and the second signal line  121  described above are usually formed of copper/copper alloy. Since the property of copper is relatively active, in order to prevent the copper/copper alloy from being oxidized or diffused into the active layer or other films and layers and causing contamination to other films and layers, optionally, a second copper diffusion barrier layer is formed on the upper surface of the copper/copper alloy layer, and a first copper diffusion barrier layer is formed on the lower surface of the copper/copper alloy layer. The first copper diffusion barrier layer and the second copper diffusion barrier layer can prevent copper from diffusing into other films and layers, such as the active layer, and can also prevent the copper/copper alloy from being oxidized in the subsequent fabrication process of other films and layers. 
     Optionally, the material constituting the copper diffusion barrier layers includes a molybdenum-niobium alloy, a molybdenum-titanium alloy, an indium tin oxide (ITO) and an indium zinc oxide (IZO). The molybdenum-niobium alloy, the molybdenum-titanium alloy, the indium tin oxide and the indium zinc oxide can well prevent the copper/copper alloy from diffusing and thus reduce the chance of being oxidized. 
     On the basis of this, since the adhesion of the photoresist on the surface of the copper diffusion barrier layer formed of the molybdenum-niobium alloy is low, when the second signal line  121  is formed, increasing the chance of generating a void at the climbing area and causing the formed second signal line  121  to be broken. 
     In this case, according to the manufacturing method provided by the arrangement of the present disclosure, in the portion of the upper surface of the first signal line  111  which overlaps with the second signal line  121 , a length of at least one edge E in the extending direction of the second signal line  121  is larger than a linear distance J between the two vertices of the edge, in order to increase the contact area of the second conductive film with the first conductive layer  11  at the climbing area, and thereby to effectively reduce the chance of generating a void in photoresist at the climbing area when the photoresist is formed on the surface of the second conductive film. 
     In the following, manufacturing process of the array substrate will be described, taking a case where the array substrate is of a bottom gate type, the first signal line  111  is a gate line and the second signal line  121  is a data line as an example. The specific process includes the following operations. 
     In a first operation, a first conductive film, i.e. a gate film, is formed on the substrate  10 , and a layer of photoresist is formed over the first conductive film  101 . 
     In a second operation, the photoresist is exposed with a mask, and after the development, a photoresist retained portion and a photoresist removed portion are formed. 
     A length of at least one side of the opaque portion of the mask at a predetermined overlapping area of the gate film and the second signal line  121  along the extending direction of the second signal line  121  is larger than a linear distance between the two vertices of the side. 
     In this way, in a portion of the formed photoresist retained portion corresponding to the portion of the upper surface of the first signal line  111  which overlaps with the second signal line  121 , a length of at least one edge in the extending direction of the second signal line  121  is larger than a linear distance between the two vertices of the edge. 
     In a third operation, the gate film is etched through an etching process to form the first conductive layer  11 . 
     Specifically, the first conductive layer  11  includes a first signal line  111 . The first signal line  111  is as shown in  FIG. 4 , and in the portion of the upper surface of the first signal line  111  which overlaps with the second signal line  121 , a length of at least one edge E in the extending direction of the second signal line  121  is larger than a linear distance J between the two vertices of the edge E. 
     Then, after the substrate  10  on which the first conductive layer  11  has been formed is cleaned, a gate insulating layer  20  may be deposited on the substrate  10  on which the first conductive layer  11  has been formed by PECVD. 
     In a fourth operation, an active layer  21  and a second conductive layer  12  are formed on the substrate  10  on which the first conductive layer  11  has been formed. 
     Specifically, the process includes the following operations. 
     In a first operation, as shown in  FIG. 8( a ) , an oxide semiconductor film  31 , a second conductive film including a first copper diffusion barrier film layer  32 , a copper/copper alloy film layer  33  and a second copper diffusion barrier film layer  34  are sequentially formed on the substrate  10  on which the first conductive layer  11  has been formed, and a photoresist  35  is formed over the second conductive film. 
     In a second operation, as shown in  FIG. 8( b ) , the photoresist  35  is exposed with a halftone mask  40 , and after the development, a photoresist completely-retained portion  351 , a photoresist half-retained portion  352 , and a photoresist completely-removed portion are formed. The photoresist completely-retained portion  351  corresponds to a source and drain electrodes  13 , the photoresist half-retained portion  352  corresponds to a region between the source and drain electrodes  13 , and the photoresist completely-removed portion corresponds to the other regions. 
     The halftone mask includes an opaque portion, a translucent portion and a transparent portion. After the photoresist  35  is exposed, the photoresist completely-retained portion  351  corresponds to the opaque portion of the halftone mask, the photoresist half-retained portion  352  corresponds to the translucent portion of the halftone mask, and the photoresist completely-removed portion corresponds to the transparent portion of the halftone mask. 
     However, in the above example, the photoresist  35  is a positive glue. When the photoresist  35  is a negative glue, the photoresist completely-retained portion  351  corresponds to the transparent portion of the halftone mask, the photoresist completely-removed portion corresponds to the opaque portion of the halftone mask, and the photoresist half-retained portion  352  also corresponds to the translucent portion of the halftone mask. 
     In a third operation, as shown in  FIG. 8( c ) , a first copper etching process is performed, to etch the first copper diffusion barrier film layer  32 , the copper/copper alloy film layer  33 , and the second copper diffusion barrier film layer  34  which correspond to the photoresist completely-removed portion. 
     During the copper etching process, usually, an overetching time of 10% to 20% may be employed to ensure that the etching is complete. In addition, under the premise of ensuring that the copper is etched completely, the overetching time should be shortened as much as possible to reduce the chance of photoresist stripping and signal line breakage. 
     In a fourth operation, as shown in  FIG. 8( d ) , the oxide semiconductor film  31  is etched, and the oxide semiconductor film  31  corresponding to the photoresist completely-removed portion is etched to obtain an oxide active layer  21 . 
     In a fifth operation, as shown in  FIG. 8( e ) , the photoresist half-retained portion  352  is removed by an ashing process. 
     Under the premise of ensuring that the photoresist half-retained portion  352  is grayed out completely, the ashing time should be shortened as much as possible to reduce the chance of photoresist stripping and signal line breakage. 
     Optionally, the photoresist  35  shown in  FIG. 8( e )  is dried. The drying temperature is 110°˜150°, and the time is 100 s˜200 s. In this way, the adhesion of the photoresist  35  on the surface of the second copper diffusion barrier layer  34  can be increased. 
     In a sixth operation S 26 , as shown in  FIG. 8( f ) , a second copper etching process is performed, to etch the exposed first copper diffusion barrier film layer  32 , the copper/copper alloy film layer  33 , and the second copper diffusion barrier film layer  34 , to form the second conductive layer  12  described above. 
     During the copper etching process, usually, an overetching time of 10% to 20% may be employed to ensure that the etching is complete. In addition, under the premise of ensuring that the copper is etched completely, the overetching time should be shortened as much as possible to reduce the chance of photoresist stripping and signal line breakage. 
     Finally, the photoresist  35  is peeled off. 
     In addition, it will be apparent to those skilled in the art that other films and layers, such as a common electrode layer, a pixel electrode layer, may be further formed on the substrate  10  on which the second conductive layer  12  has been formed, which will not be elaborated in the present disclosure. 
     In addition, optionally, before S 22 , the manufacturing method further includes: roughening the second conductive film. It should be noted that the specific manner of the above roughening treatment is not limited in the present disclosure, as long as the surface of the second conductive film is rough after the second conductive film is processed. 
     In this case, since the surface of the second conductive film is rough, when the photoresist  35  is formed on the second conductive film, the adhesion effect of the photoresist  35  on the second conductive film can be increased, thereby reducing the chance of generating a void in the photoresist  35  at the climbing area. 
     For example, the roughening treatment of the second conductive film may include: coating the surface of the second conductive film with a photoresist  35 , pre-baking, exposing, developing, and post-baking the photoresist  35 , and removing the photoresist  35 . In this way, the surface of the second conductive film can be treated by the high temperature photoresist  35 , so that the surface of the second conductive film can be rough. 
     In the present arrangement, the oxide active layer  21  and the second conductive layer  12  are formed by one patterning process, which can have the effect of simplifying the process, and can reduce the process cost. 
     However, the oxide active layer  21  may be formed by one patterning process first, and then the second conductive layer  12  is formed by another patterning process. In this case, an ordinary mask may be employed for the exposure process. By controlling the shape of the mask, the shape of the upper surface of the second signal line  121  in the second conductive layer  12  as formed can be controlled. 
     An arrangement of the present disclosure provides an array substrate. As shown in  FIG. 3 , the array substrate includes a substrate  10 . A first signal line  111  and a second signal line  121  are sequentially disposed on the substrate  10 . The first signal line  111  and the second signal line  121  are disposed intersecting each other and insulated from each other. 
     As shown in  FIG. 4 , in the portion of the upper surface of the first signal line  111  which overlaps with the second signal line  121 , a length of at least one edge E in the extending direction of the second signal line  121  is larger than a linear distance J between the two vertices of the edge E. 
     It should be noted that the first signal line  111  and the second signal line  121  are sequentially disposed on the substrate  10 , so the second signal line  121  is located above the first signal line  111 , and thus a climbing phenomenon may occur for the second signal line  121  at the overlapping area of the second signal line  121  and the first signal line  111 . 
     Based on this, the above array substrate provided by the present disclosure includes a first signal line  111  and a second signal line  121  which are disposed intersecting each other and insulated from each other. In the portion of the upper surface of the first signal line  111  which overlaps with the second signal line  121 , a length of at least one edge E in the extending direction of the second signal line  121  is larger than a linear distance J between the two vertices of the edge E. When the second signal line  121  is formed by a patterning process on the substrate  10  on which the first signal line  111  has been formed, assuming that the thickness of the first signal line  111  is constant, compared to the case where the edge E has a length equal to the linear distance between the two vertices of the edge E, the contact area of the second conductive film with the first conductive layer  11  at the climbing area will be increased when the second conductive layer  12  is formed by the patterning process. In this way, when photoresist is formed on the surface of the second conductive film, the photoresist can have an increased contact area with the second conductive film at the climbing area, which can reduce the chance of generating voids in the photoresist at the climbing area. In turn, during the etching process, it can reduce the chance of the etching liquid intruding into the second conductive film through the voids and causing the second signal line  121  to be broken. 
     On the basis of this, the present disclosure does not limit the shape of the edge E as long as the length of the edge E is larger than the linear distance J between the two vertices of the edge E. For example, the edge E may be as shown in  FIG. 4 , the edge E may be an arc line; or the edge E may be a polygonal line. 
     On the basis of this, in order to increase the contact area of the photoresist  35  with the second conductive film at the climbing area when the second signal line  121  is formed by the patterning process, optionally, in the portion of the upper surface of the first signal line  111  which overlaps with the second signal line  121 , two edges E in the extending direction of the second signal line  121  are all arc lines. In this case, as shown in  FIG. 5 , the arc lines of the two edges E have the same protrusion direction. However, the arc lines of the two edges E may have different protrusion directions. 
     Further, in order to reduce the chance that the first signal line  111  is broken due to the narrow width of the portion of the upper surface of the first signal line  111  which overlaps with the second signal line  121 , preferably, in the portion of the upper surface of the first signal line  111  which overlaps with the second signal line  121 , the two edges E along the extending direction of the second signal line  121  may be arc lines having the same protrusion direction, or having protrusion directions pointing away from each other. 
     On this basis, in order to further increase the contact area of the photoresist  35  with the second conductive film at the climbing area, optionally, as shown in  FIG. 5 , a width W 2  of the second signal line  121  in an overlapping region of orthogonal projections of the second signal line  121  and the first signal line  111  on the substrate  10  is larger than a width W 1  of the second signal line  121  in a non-overlapping region of the orthogonal projections of the second signal line  121  and the first signal line  111  on the substrate  10 . The width of the second signal line  121  refers to a linear distance from one side of the second signal line  121  to the other side of the second signal line  121  along the extending direction of the first signal line  111  (i.e. the X direction shown in  FIG. 3 ). 
     In this case, when the photoresist  35  is formed on the surface of the second conductive film, at the climbing area, compared to the case where W 1 =W 2  in the second signal line  121 , the photoresist  35  and the upper surface of the second conductive film can have a further increased contact area, so that the chance of generation of voids in the photoresist  35  at the climbing area can be further reduced. 
     Further, the first signal line  111  and the second signal line  121  described above are usually formed of copper/copper alloy. Since the property of copper is relatively active, in order to prevent the copper/copper alloy from being oxidized or diffused into the active layer or other films and layers and causing contamination to other films and layers, optionally, the first signal line  111  and the second signal line  121  include a first copper diffusion barrier layer, a copper/copper alloy layer, and a second copper diffusion barrier layer that are sequentially disposed. 
     In this way, the first copper diffusion barrier layer and the second copper diffusion barrier layer can prevent copper from diffusing into other films and layers, such as the active layer, and can also prevent the copper/copper alloy from being oxidized in the subsequent fabrication process of other films and layers. 
     Optionally, the material constituting the copper diffusion barrier layers includes a molybdenum-niobium alloy, a molybdenum-titanium alloy, an indium tin oxide and an indium zinc oxide. The molybdenum-niobium alloy, the molybdenum-titanium alloy, the indium tin oxide and the indium zinc oxide can well prevent the copper/copper alloy from diffusing and thus reduce the chance of being oxidized. 
     In addition, the present disclosure does not limit the type of the array substrate, and may be, for example, a bottom gate type array substrate or a top gate type array substrate. In the array substrate, a plurality of signal lines are disposed intersecting each other. When the array substrate is of a bottom gate type, as shown in  FIG. 3 , the first signal line  111  may be a gate line or a common line in the same layer as the gate line, and the second signal line  121  is a data line. When the array substrate is of the top gate type, the first signal line  111  is a data line, and the second signal line  121  is a gate line or a common line in the same layer as the gate line. 
     An arrangement of the present disclosure provides a display device, including any of the array substrates described above, which has the same structure and improvements as the array substrate provided by the foregoing arrangements. Since in the foregoing arrangements, the structure and improvements of the array substrate have been described in detail, the description thereof will not be repeated herein. 
     The above is only the specific arrangements of the present disclosure, but the scope of the present disclosure is not limited thereto, and modifications or substitutions easily conceived by any person skilled in the art within the technical scope of the present disclosure should be covered by the scope of the present disclosure. Therefore, the scope of the present disclosure should be determined by the scope of the appended claims.