Patent Publication Number: US-11646261-B2

Title: Integrated circuits including multi-layer conducting lines

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. application Ser. No. 16/519,725, filed Jul. 23, 2019, which claims the benefits of Korean Patent Application No. 10-2018-0104019, filed on Aug. 31, 2018, and Korean Patent Application No. 10-2019-0035178, filed on Mar. 27, 2019, in the Korean Intellectual Property Office, the disclosures of each of which are incorporated herein in their entirety by reference. 
    
    
     BACKGROUND 
     The inventive concepts relate to integrated circuits, and more particularly, to integrated circuits including multi-layered conducting lines. 
     As integrated circuits with high operating speeds have been demanded, a signal delay occurring in wires of integrated circuits has been considered a significant design factor. A wire electrically connecting two or more devices with each other in an integrated circuit may have an electrical resistance thereof (also referred to herein as simply a “resistance” of the wire), and the wire may generate a capacitance with a neighboring (e.g., adjacent) wire. A signal delay may occur due to the resistance and capacitance of the wires, and as the resistance and the capacitance of the wires increase, the signal delay occurring in the wires may also increase. Also, due to a miniaturization of semiconductor processes, sizes of patterns included in wires and distances among adjacent patterns may be reduced, and accordingly, a signal delay occurring in one or more of the wires may become worse, and moreover, an operating speed of an integrated circuit including the wires may be reduced. 
     SUMMARY 
     The inventive concepts provide multi-layer conducting lines configured to reduce a signal delay and integrated circuits of a high integration degree and including the multi-layer conducting lines. 
     According to some example embodiments of the inventive concepts, an integrated circuit may include a first wiring layer including a plurality of first patterns, a first via layer including a plurality of first vias, the first via layer adjacent to the first wiring layer in a first direction, and a multi-layer conducting line including a first portion and a second portion, the first portion extending in a second direction perpendicular to the first direction in the first wiring layer and the second portion extending in the second direction in the first via layer. The first portion and the second portion may be integrally formed with each other. 
     According to some example embodiments of the inventive concepts, an integrated circuit may include a first wiring layer including a plurality of first patterns, a first via layer including a plurality of first vias, the first via layer adjacent to the first wiring layer in a first direction, and a multi-layer conducting line including a first portion, a second portion, and a first barrier layer, the first portion extending in a second direction perpendicular to the first direction in the first wiring layer, the second portion extending in the second direction in the first via layer, and the first barrier layer extending in the second direction between the first portion and the second portion. 
     According to some example embodiments of the inventive concepts, an integrated circuit may include a plurality of layers stacked in a first direction, a plurality of unit circuits at least partially overlapping each other in a second direction that is perpendicular to the first direction and configured to operate in parallel with one another, control circuitry configured to generate a control signal to control the plurality of unit circuits, and a multi-layer conducting line configured to transfer the control signal from the control circuitry to the plurality of unit circuits. The multi-layer conducting line may be integrally formed in a wiring layer and a via layer and extends in the second direction. The wiring layer and the via layer may be adjacent to each other. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Some example embodiments of the inventive concepts will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings in which: 
         FIG.  1    is a diagram of an integrated circuit according to some example embodiments; 
         FIG.  2    is a diagram showing a layout of an integrated circuit according to some example embodiments; 
         FIGS.  3 A and  3 B  are diagrams showing examples of multi-layer conducting lines according to some example embodiments; 
         FIG.  4    is a diagram illustrating processes of forming multi-layer conducting line according to some example embodiments; 
         FIGS.  5 A and  5 B  are diagrams showing examples of multi-layer conducting lines according to some example embodiments; 
         FIGS.  6 A,  6 B,  6 C,  6 D, and  6 E  are diagrams showing examples of multi-layer conducting lines according to some example embodiments; 
         FIGS.  7 A and  7 B  are diagrams showing examples of multi-layer conducting lines according to some example embodiments; 
         FIGS.  8 A and  8 B  are diagrams showing examples of multi-layer conducting lines according to some example embodiments; 
         FIG.  9    is a block diagram of a memory device according to some example embodiments; 
         FIG.  10    is a diagram partially showing a layout of the memory device of  FIG.  9   , according to some example embodiments; 
         FIG.  11    is a block diagram of an image sensor according to some example embodiments; 
         FIG.  12    is a block diagram of a display apparatus according to some example embodiments; and 
         FIG.  13    is a block diagram of a system-on-chip (SoC) according to some example embodiments. 
     
    
    
     DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS 
       FIG.  1    is a diagram of an integrated circuit  10  according to some example embodiments. In detail,  FIG.  1    is a block diagram of the integrated circuit  10 , and additionally shows some conducting lines  14  and  16  included in a layout of the integrated circuit  10 . A Z-axis direction as used herein is a direction in which a plurality of layers are stacked in a semiconductor process for manufacturing the integrated circuit  10 , and may be referred to as a first direction or a vertical direction, and an X-axis direction and a Y-axis direction may be respectively referred to as a second direction and a third direction. An element disposed in the +Z-axis direction as compared with another element may be considered to be located on another element, and an element disposed in the −Z-axis direction as compared with another element may be considered to be located under another element. Also, among surfaces of an element, a surface exposed in the +Z-axis direction may be referred to as an upper surface, a surface exposed in the −Z-axis direction may be referred to as a lower surface, and a surface exposed in the X-axis direction or the Y-axis direction may be referred to as a side surface. Unless otherwise defined, a length of an element may denote a length in an extending direction, and a width of an element may denote a length in a direction perpendicular to the extending direction. Also, a height of an element may denote a length in the Z-axis direction. Accompanying drawings showing a layout may denote only some of layers for convenience of description. 
     The integrated circuit  10 , also referred to herein as “integrated circuitry”, may denote an arbitrary device manufactured through a semiconductor process. In some example embodiments, the integrated circuit  10  may be a memory device including a plurality of memory cells, a processor including at least one core, a sensor for sensing external signals, or a device including a plurality of functional blocks, e.g., a system-on-chip (SoC). As shown in  FIG.  1   , the integrated circuit  10  may include a control circuit  12  (also referred to herein as “control circuitry”) and a plurality of unit circuits (also referred to herein as “unit circuitries”) U 1 , . . . , Un (n is an integer greater than 1), and may additionally include a plurality of conducting lines  14  and  16 . It will be understood that, as used herein, a conducting line (e.g., each conducting line of the plurality of conducting lines  14  and  16 ) may be referred to as a “wire” that is electrically conductive (e.g., is configured to conduct electricity therethrough between opposite ends thereof). 
     The plurality of unit circuits U 1 , . . . , Un may have the same structure as one another, and may be configured to operate in parallel with one another. As a non-limiting example, as described later with reference to  FIG.  9   , the plurality of unit circuits U 1 , . . . , Un may be memory cells storing data in a memory device (e.g., a plurality of memory cells each configured to store at least one bit of data), as described later with reference to  FIG.  11   , the plurality of unit circuits U 1 , . . . , Un may be pixels sensing light in an image sensor (e.g., a plurality of pixels each configured to sense incident light), and as described later with reference to  FIG.  12   , the plurality of unit circuits U 1 , . . . , Un may be pixels emitting light in a display apparatus (e.g., a plurality of pixels each configured to emit light). Parallel operations of the plurality of unit circuits U 1 , . . . , Un may be demanded to be performed simultaneously, and when there is a large difference between time points at which the parallel operations are performed, an operating speed of the integrated circuit  10  may be reduced, and further, a malfunction may be caused. As shown in  FIG.  1   , and with reference to at least  FIG.  2   , the plurality of unit circuits U 1 , . . . , Un may be disposed in the X-axis direction (e.g., the second direction as described below) such that the plurality of unit circuits U 1 , . . . , Un may be understood to at least partially overlap with each other in the X-axis direction. 
     The control circuit  12 , which may be referred to herein as “control circuitry,” may include processing circuitry such as hardware including logic circuits; a hardware/software combination such as a processor executing software; or a combination thereof. For example, the control circuit  12  more specifically may include, but is not limited to, a central processing unit (CPU), an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable gate array (FPGA), a System-on-Chip (SoC), a programmable logic unit, a microprocessor, application-specific integrated circuit (ASIC), etc. The control circuit  12  may generate a control signal CTR for controlling the plurality of unit circuits U 1 , . . . , Un. In some example embodiments, the control circuit  12  may generate the control signal CTR having a variable voltage and/or current for controlling operations of the plurality of unit circuits U 1 , . . . , Un. As shown in  FIG.  1   , the plurality of unit circuits U 1 , . . . , Un may be disposed (“located”) adjacent to one another, and the control circuit  12  may be disposed adjacent to a side of the plurality of unit circuits U 1 , . . . , Un. Also, the plurality of unit circuits U 1 , . . . , Un may be electrically connected to a first conducting line  14  that extends in the X-axis direction (or the second direction), and may receive the control signal CTR via the first conducting line  14 . Due to the delay of the control signal CTR in the first conducting line  14 , the control signal CTR generated by the control circuit  12  may firstly reach the first unit circuit U 1  and may finally reach the n-th unit circuit Un. Accordingly, the parallel operations of the first to n-th unit circuits U 1  and Un may be respectively performed at different time points. 
     As shown in  FIG.  1   , the delay of control signal CTR occurring in the first conducting line  14  may depend upon a resistance RP of the first conducting line  14  and a capacitance CP formed by the first conducting line  14  and the second conducting line  16  adjacent to the first conducting line  14 . The resistance RP may be proportional to a length L of the first conducting line  14  and inversely proportional to a width W of the first conducting line  14 , and the capacitance CP may be inversely proportional to a distance S between the first conducting line  14  and the second conducting line  16 . Accordingly, in order to reduce the delay of the control signal CTR occurring in the first conducting line  14 , the first conducting line  14  may be required to have a relatively less length L and a relatively greater width W, and the first conducting line  14  and the second conducting line  16  may be required to have a relatively greater distance S. However, reduction of the length L of the first conducting line  14  may be restricted due to the number and sizes of the plurality of unit circuits U 1 , . . . , Un, and an increase in the width W and the distance S may be restricted due to a spatial limitation of the integrated circuit  10 . 
     As described below with reference to accompanying drawings, the first conducting line  14  transferring the control signal CTR to the plurality of unit circuits U 1 , . . . , Un may include multi-layer conducting lines, and accordingly, the first conducting line  14  may maintain or increase the distance S to the adjacent second conducting line  16  while having a lower resistance RP. Accordingly, the first conducting line  14  may provide reduced delay, and a difference between the time points at which the parallel operations of the first unit pixel U 1  and the n-th unit pixel Un are performed may be greatly reduced. In addition, in some example embodiments, due to the reduced width W of the first conducting line  14 , the second conducting line  16  may have an increased width, and accordingly, an operating speed and/or operating reliability of the integrated circuit  10  may be improved. 
       FIG.  2    is a diagram showing a layout of an integrated circuit  20  according to some example embodiments. In detail,  FIG.  2    partially shows a M 2  layer, a V 2  layer, and a M 3  layer from among a plurality of layers included in a layout of the integrated circuit  20 . As described above with reference to  FIG.  1   , the integrated circuit  20  of  FIG.  2    may include multi-layered conducting lines ML for transferring a control signal to a plurality of unit circuits operating in parallel with one another. For convenience of description,  FIG.  2    only shows one multi-layer conducting line ML and some other patterns included in the layout of the integrated circuit  20 . 
     The integrated circuit  20  may include a plurality of wiring layers and a plurality of via layers in a plurality of layers stacked in the Z-axis direction (or the first direction). Accordingly, as shown in  FIG.  2   , the integrated circuit  20  may include a plurality of layers stacked in the Z-axis direction. The integrated circuit  20  may further include the plurality of unit circuits U 1 , . . . , Un shown in  FIG.  1   , where the plurality of unit circuits are disposed in the X-axis direction such that the plurality of unit circuits U 1 , . . . , Un may be understood to at least partially overlap with each other in the X-axis direction. The integrated circuit  20  may further include the control circuit  12  shown in  FIG.  1    (also referred to herein as “control circuitry”), where the control circuit  12  is configured to generate a control signal to control the plurality of unit circuits U 1 , . . . , Un. In some example embodiments, the multi-layer conducting line ML is configured to transfer the control signal from the control circuit  12  to the plurality of unit circuit U 1 , . . . , Un. As further described below with reference to at least  FIGS.  9 - 12   , it will be understood that the multi-layer conducting line ML may be electrically connected to control electrodes of transistors included in the plurality of unit circuits U 1 , . . . , Un. As described further below, the multi-layer conducting line ML may be integrally formed in a wiring layer (e.g., M 2  layer) and a via layer (e.g., V 2  layer) and extends in the X-axis direction, where the wiring layer and the via layer are adjacent to each other. The wiring layer may include a plurality of patterns and the via layer may include a plurality of vias. In some example embodiments, as shown in  FIG.  2   , the M 2  layer as a wiring layer (e.g., a first wiring layer) may include a first pattern M 21  and a second pattern M 22  extending in the Y-axis direction and the M 3  layer as a wiring layer (e.g., a second wiring layer) may include a third pattern M 31  and a fourth pattern M 32  extending in the X-axis direction. Also, a first via V 21  and a second via V 22  may be provided in the V 2  layer, that is, the via layer. As shown, the V 2  layer (via layer) may be adjacent to the M 2  layer (first wiring layer) in the Z-axis direction (or a first direction). As shown, the M 3  layer (second wiring layer) may be adjacent to the V 2  layer (via layer) in the Z-axis direction (or a first direction). In addition, the first via V 21  may be connected to the first pattern M 21  and a third pattern M 31 , and the second via V 22  may be connected to the second pattern M 22  and a fourth pattern M 32 . The patterns and the vias may be spaced from one another (e.g., isolated from direct contact with each other) by a minimum distance or greater, wherein the minimum distance is determined based on the semiconductor process for manufacturing the integrated circuit  20 . In some example embodiments, the first and second patterns M 21  and M 22  may be separate from each other (e.g., isolated from direct contact with each other) by at least a first distance S 1 . In some example embodiments, as shown in  FIG.  2   , a first distance S 1  between the first pattern M 21  and the second pattern M 22  in the X-axis direction in the M 2  layer and a second distance S 2  between the third pattern M 31  and the fourth pattern M 32  in the Y-axis direction in the M 3  layer may be equal to or greater than the minimum distance determined according to the semiconductor process. 
     The multi-layer conducting line ML may extend in the X-axis direction (or the second direction perpendicular to the Z-axis direction) through two or more adjacent layers. In some example embodiments, the multi-layer conducting line ML may be isolated from direct contact with the first and second patterns M 21  and M 22  of the M 2  layer by a distance S 2   a  that is greater than the first distance S 1 . In some example embodiments, as shown in  FIG.  2   , the multi-layer conducting line ML may include a first portion P 1  extending in the X-axis direction in the M 2  layer, a second portion P 2  extending in the X-axis direction in the V 2  layer, and a third portion P 3  extending in the X-axis direction in the M 3  layer. Although the multi-layer conducting line ML extend in the X-axis direction in three successive layers in  FIG.  2   , as described later with reference to  FIGS.  3 A and  3 B , etc., the multi-layer conducting line ML may extend in the X-axis direction in two adjacent layers (e.g., layers M 2 /V 2  or layers V 2 /M 3 ), or as described later with reference to  FIGS.  8 A and  8 B , the multi-layer conducting line ML may extend in the X-axis direction in four or more successive layers. Accordingly, the multi-layer conducting line ML may have a reduced resistance, as compared with a structure extending in a single layer and a structure in which extensions are connected by vias in two wiring layers. As shown in  FIG.  2   , the multi-layer conducting line ML may have a length L in the X-axis direction, a width W in the Y-axis direction, and a height H in the Z-axis direction. As shown in  FIG.  2   , the third portion P 3  may extend in the X-axis direction (or second direction) by a length L that is equal to a length L of the first portion P 1 . As shown in  FIG.  2   , the second portion P 2  may have a length L that is equal to a length L of the first portion P 1 . 
     Heights of the layers M 2 , V 2 , and M 3  shown in  FIG.  2   , that is, the lengths in the Z-axis direction, are examples, and may be different from those examples of  FIG.  2   . Also, one or more embodiments will be described based on the layers M 2 , V 2 , and M 3  hereinafter, but it will be understood that multi-layer conducting lines according to some example embodiments may be also included in other wiring layers and via layers. 
       FIGS.  3 A and  3 B  are diagrams showing examples of multi-layer conducting lines  30   a  and  30   b  according to some example embodiments. In detail,  FIGS.  3 A and  3 B  show the multi-layer conducting lines  30   a  and  30   b , respectively, which are integrally formed in two adjacent layers and have a length L in the X-axis direction. Hereinafter, redundant descriptions about  FIGS.  3 A and  3 B  will be omitted. 
     Referring to  FIG.  3 A , the multi-layer conducting line  30   a  may include the first portion P 1  extending in the X-axis direction in the M 3  layer and the second portion P 2  extending in the X-axis direction in the V 2  layer, and the first portion P 1  and the second portion P 2  may be integrally formed with each other. Accordingly, it will be understood that the multi-layer conducting line  30   a  may be integrally formed in a wiring layer (e.g., M 3  layer) and a via layer (e.g., V 2  layer) and extends in the X-axis direction, where the wiring layer and the via layer are adjacent to each other. In the specification herein, ‘elements formed integrally with each other’ may denote that the elements are continuously formed by using a same material, and the elements that are integrally formed with each other may be denoted by a single outline in the drawings. In some example embodiments, as described later with reference to  FIGS.  4 ,  5 A, and  5 B , the first portion P 1  in the M 3  layer and the second portion P 2  in the V 2  layer that are surrounded by a single outline in  FIG.  3 A  may include the same material, e.g., metal such as aluminum (Al), copper (Cu), etc., and a boundary between the first portion P 1  and the second portion P 2  (or boundary between the M 3  layer and the V 2  layer) may also include the same material. In some example embodiments, elements that are integrally formed with each other may comprise a single, uniform part instead of separate elements coupled together. In some example embodiments, unlike the example of  FIG.  3 A , portions that are not formed integrally with each other may include a different material (e.g., an insulator, a barrier wall, etc.) disposed therebetween. In the specification, it will be described that the multi-layer conducting line includes the metal such as Al or Cu, but the multi-layer conducting line may include a conductive material different from the metal. 
     Due to the first portion P 1  and the second portion P 2  that are provided integrally with each other, the multi-layer conducting line  30   a  may have a reduced resistance. As described above with reference to  FIG.  1   , since it is restricted to increase the width of the conducting line due to the spatial limitation, it may be considered to use the conducting line including patterns that extend in the same direction in two or more wiring layers and connected to one another through vias unlike the multi-layer conducting line  30   a  of  FIG.  3 A , in order to reduce the resistance of the conducting line. However, in the above conducting line, the reduction of the resistance of the conducting line may be restricted due to a resistance provided by the via in the Z-axis direction and a resistance of a barrier layer between patterns of the wiring layer and vias, and moreover, the reduction of the resistance may be further diminished as the semiconductor process becomes miniaturized. In some example embodiments, as shown in  FIG.  3 A , the multi-layer conducting line  30   a  formed integrally throughout two or more adjacent layers may be free from the influence of the resistance of the via and the resistance of the barrier layer, and may also have a reduced resistance even with the miniaturized semiconductor process. 
     As shown in  FIG.  3 A , an interlayer insulator IL may be disposed on a lower surface of the multi-layer conducting line  30   a  and thus may be between the multi-layer conducting line  30   a  and the M 2  layer. The interlayer insulator IL may insulate the multi-layer conducting line  30   a  (or the second portion P 2 ) from the other patterns formed in the M 2  layer. As described above with reference to  FIG.  2   , the via layer such as the V 2  layer may include the vias for connecting the patterns of adjacent wiring layers (that is, the M 2  layer and the M 3  layer) to one another, and thus, the interlayer insulator IL may be disposed to insulate the second portion P 2  extending in the X-axis direction in the V 2  layer from the patterns in the M 2  layer that is adjacent to the V 2  layer, unlike the vias formed in the via layer. In some example embodiments, the interlayer insulator IL may be referred to as an interlayer insulator film, an interlayer dielectric, etc. 
     Referring to  FIG.  3 B , the multi-layer conducting line  30   b  may include the first portion P 1  extending in the X-axis direction in the M 2  layer and the second portion P 2  extending in the X-axis direction in the V 2  layer, and the first portion P 1  and the second portion P 2  may be integrally formed with each other. In some example embodiments, the first portion P 1  in the M 2  layer and the second portion P 2  in the V 2  layer included within the single outline of  FIG.  3 B  may include the same material, e.g., metal such as Cu, and a boundary between the first portion P 1  and the second portion P 2  (or boundary between the M 2  layer and the V 2  layer) may also include the same metal. 
     As shown in  FIG.  3 B , an interlayer insulator IL may be disposed on an upper surface of the multi-layer conducting line  30   b  and thus may be between the multi-layer conducting line  30   b  and the M 3  layer. As described above, unlike the vias for connecting the patterns in the adjacent M 2  layer and the M 3  layer to one another, the interlayer insulator IL may be disposed to insulate the second portion P 2  extending in the X-axis direction in the V 2  layer from the patterns in the M 3  layer that is adjacent to the V 2  layer. Accordingly, the patterns disposed in the M 3  layer on the multi-layer conducting line  30   b  may be insulated from the multi-layer conducting line  30   b.    
       FIG.  4    is a diagram illustrating processes of forming the multi-layer conducting line  30   a  according to some example embodiments. In detail,  FIG.  4    sequentially shows cross-sections taken along a plane perpendicular to a direction in which the multi-layer conducting line  30   a  extends, that is, the X-axis direction, according to processes of forming the multi-layer conducting line  30   a  of  FIG.  3 A . Hereinafter,  FIG.  4    will be described with reference to  FIG.  3 A . 
     In some example embodiments, the multi-layer conducting line  30   a  may be formed by a damascene process. The damascene process may denote a technique that finishes forming patterns by making a space through an etching, filling the space with a material for forming the patterns, and then polishing the patterns. In particular, a technique of etching simultaneously two adjacent layers, e.g., the via layer and the wiring layer, filling the space with metal, and polishing the space to form the vias and patterns at the same time may be referred to as a dual damascene process. 
     Referring to  FIG.  4   , in operation S 41 , an operation of partially etching the V 2  layer and the M 3  layer may be performed. In some example embodiments, the V 2  layer and the M 3  layer may be partially etched according to the length L and the width W of the multi-layer conducting line  30   a . Next, in operation S 42 , an operation of forming a barrier layer may be performed. The barrier layer may be configured to reduce or prevent the metal forming the multi-layer conducting line  30   a , oxygen, or moisture from diffusing to outside, and accordingly, the interlayer insulator between the V 2  layer and the M 3  layer, as well as the insulator included in the V 2  layer and the M 3  layer, may be protected. In some example embodiments, the barrier layer may include a conductive material, in some example embodiments, Ti/TiN, Ta/TaN, etc., and may be formed by a physical vapor deposition (PVD) method. Also, in some example embodiments, a seed layer for filling the material may be formed after forming the barrier layer, and herein, the seed layer may be considered to be included in the barrier layer. In some example embodiments, when the multi-layer conducting line  30   a  includes Cu, a seed layer for filling Cu in an electroplating method may be formed by the PVD method. 
     In operation S 43 , an operation of filling metal may be performed. In some example embodiments, as described above, the seed layer may be disposed on the barrier layer, and the operation of filling metal material in the electroplating method may be performed. In operation S 44 , a polishing operation may be performed. In some example embodiments, as shown in operation S 43  of  FIG.  4   , the metal material may be formed on the M 3  layer in operation S 43 , the barrier layer, as well as the metal on the M 3  layer, may be removed by the polishing operation such as chemical mechanical polishing (CMP), and then, an interlayer insulating film may be formed. Accordingly, as shown in operation S 44  of  FIG.  4   , the multi-layer conducting line  30   a  may include the first portion P 1  extending in the X-axis direction in the M 3  layer and the second portion P 2  extending in the X-axis direction in the V 2  layer, and the first portion P 1  and the second portion P 2  may be integrally formed with each other. In some example embodiments, as shown in  FIG.  4   , the first portion P 1  and the second portion P 2  may have substantially the same width W, and as described later with reference to  FIGS.  5 A and  5 B , the first portion P 1  and the second portion P 2  may have different widths from each other. As shown in  FIG.  4   , the barrier layer may be at least partially in a surface of the multi-layer conducting line when the multi-layer conducting line is formed. 
       FIGS.  5 A and  5 B  are diagrams showing examples of multi-layer conducting lines according to some example embodiments. In detail,  FIG.  5 A  shows an example of a cross-section of the multi-layer conducting line  30   a  taken along a plane perpendicular to the X-axis direction, in which the multi-layer conducting line  30   a  of  FIG.  3 A  extends, and  FIG.  5 B  shows an example of a cross-section of the multi-layer conducting line  30   b  taken along a plane perpendicular to the X-axis direction, in which the multi-layer conducting line  30   b  of  FIG.  3 B  extends. Hereinafter, redundant descriptions about  FIGS.  5 A and  5 B  will be omitted. 
     Referring to  FIG.  5 A , the multi-layer conducting line  30   a  may include the first portion P 1  extending in the X-axis direction in the M 3  layer and the second portion P 2  extending in the X-axis direction in the V 2  layer, and the first portion P 1  and the second portion P 2  may have different widths, that is, lengths in the Y-axis direction, from each other. In some example embodiments, as shown in  FIG.  5 A , the first portion P 1 , that is, an upper portion of the multi-layer conducting line  30   a , has a first width W 1 , and the second portion P 2 , that is, a lower portion of the multi-layer conducting line  30   a , may have a second width W 2 . The second width W 2  may be less than the first width W 1 . Also, in some example embodiments, side surfaces of the first portion P 1  and the second portion P 2  may be inclined surfaces that are not in parallel with the Z-axis direction, as shown in  FIG.  5 A . 
     Similarly, referring to  FIG.  5 B , the multi-layer conducting line  30   b  may include the first portion P 1  extending in the X-axis direction in the M 2  layer and the second portion P 2  extending in the X-axis direction in the V 2  layer, and the first portion P 1  and the second portion P 2  may have different widths, that is, lengths in the Y-axis direction, from each other. In some example embodiments, as shown in  FIG.  5 B , the second portion P 2 , that is, an upper portion of the multi-layer conducting line  30   b , may have the second width W 2 , and the first portion P 1 , that is, a lower portion of the multi-layer conducting line  30   b , may have the first width W 1 . The first width W 1  may be less than the second width W 2 . Also, in some example embodiments, side surfaces of the first portion P 1  and the second portion P 2  may be inclined surfaces that are not in parallel with the Z-axis direction, as shown in  FIG.  5 B . 
       FIGS.  6 A,  6 B,  6 C,  6 D, and  6 E  are diagrams showing examples of multi-layer conducting lines  60   a  to  60   e  according to some example embodiments. In detail,  FIGS.  6 A to  6 E  show the multi-layer conducting lines  60   a ,  60   b ,  60   c ,  60   d , and  60   e  each including portions that have a length L in the X-axis direction and extend together in the X-axis direction respectively in three successive layers. It would be appreciated from  FIGS.  6 A to  6 E  that the multi-layer conducting lines as shown in  FIGS.  6 A to  6 E  having various structures may be formed according to the semiconductor process, and multi-layer conducting lines including the portions extending together in three successive layers in a different structure from those of  FIGS.  6 A to  6 E  may be implemented. Hereinafter, redundant descriptions about  FIGS.  6 A to  6 E  will be omitted. 
     Referring to  FIG.  6 A , the multi-layer conducting line  60   a  may include the first portion P 1  extending in the X-axis direction in the M 3  layer, the second portion P 2  extending in the X-axis direction in the V 2  layer, and a third portion P 3  extending in the X-axis direction in the M 2  layer. The first portion P 1 , the second portion P 2 , and the third portion P 3  may be integrally formed with one another. As described above with reference to  FIG.  3 A , the first portion P 1 , the second portion P 2 , and the third portion P 3  formed integrally with one another may include the same material, e.g., metal, and boundaries among the first portion P 1 , the second portion P 2 , and the third portion P 3  may include the same metal material. In some example embodiments, the multi-layer conducting line  60   a  may be formed by the damascene process, as described above with reference to  FIG.  4   . 
     Referring to  FIG.  6 B , the multi-layer conducting line  60   b  may include the first portion P 1  extending in the X-axis direction in the M 3  layer, the second portion P 2  extending in the X-axis direction in the V 2  layer, and a third portion P 3  extending in the X-axis direction in the M 2  layer. The first portion P 1  and the second portion P 2  may be integrally formed with each another. That is, as shown in  FIG.  6 B , the first portion P 1  and the second portion P 2  on an upper portion of the multi-layer conducting line  60   b  within a single outline may be formed integrally with each other, and the third portion P 3  within another single outline on a lower portion of the multi-layer conducting line  60   b  may not be formed integrally with the first portion P 1  and the second portion P 2 . In some example embodiments, a different material, e.g., a barrier layer, may be disposed between the second portion P 2  and the third portion P 3  in the multi-layer conducting line  60   b . In some example embodiments, as compared with a case, in which the first portion P 1  in the M 3  layer and the third portion P 3  in the M 2  layer are connected to each other via at least one via in the V 2  layer instead of the second portion P 2  in the V 2  layer extending in the X-axis direction unlike the example of  FIG.  6 B , the multi-layer conducting line  60   b  of  FIG.  6 B  may have a reduced resistance due to a barrier layer omitted between the V 2  layer and the M 3  layer, and due to the second portion P 2  extending in the X-axis direction. 
     Referring to  FIG.  6 C , the multi-layer conducting line  60   c  may include the first portion P 1  extending in the X-axis direction in the M 2  layer, the second portion P 2  extending in the X-axis direction in the V 2  layer, and a third portion P 3  extending in the X-axis direction in the M 3  layer. The first portion P 1  and the second portion P 2  may be integrally formed with each another. That is, as shown in  FIG.  6 C , the first portion P 1  and the second portion P 2  on a lower portion of the multi-layer conducting line  60   c  within a single outline may be formed integrally with each other, and the third portion P 3  within another single outline on an upper portion of the multi-layer conducting line  60   c  may not be formed integrally with the first portion P 1  and the second portion P 2 . In some example embodiments, a different material, e.g., a barrier layer, may be disposed between the second portion P 2  and the third portion P 3  in the multi-layer conducting line  60   c . In some example embodiments, as compared with a case, in which the first portion P 1  in the M 2  layer and the third portion P 3  in the M 3  layer are connected to each other through at least one via in the V 2  layer instead of the second portion P 2  in the V 2  layer extending in the X-axis direction unlike the example of  FIG.  6 C , the multi-layer conducting line  60   c  of  FIG.  6 C  may have a reduced resistance due to a barrier layer omitted between the V 2  layer and the M 2  layer, and due to the second portion P 2  extending in the X-axis direction. 
     Referring to  FIG.  6 D , the multi-layer conducting line  60   d  may include the first portion P 1  extending in the X-axis direction in the M 3  layer, the second portion P 2  extending in the X-axis direction in the V 2  layer, and a third portion P 3  extending in the X-axis direction in the M 2  layer. The first portion P 1 , the second portion P 2 , and the third portion P 3  may be separately formed from one another. That is, as shown in  FIG.  6 D , the first portion P 1 , the second portion P 2 , and the third portion P 3  that are included respectively by a single outline in the multi-layer conducting line  60   d  may not be formed integrally with one another. Accordingly, a different material such as a barrier layer may be disposed between the first portion P 1  and the second portion P 2  of the multi-layer conducting line  60   d  and may extend in the X-axis direction therebetween, and a different material such as a barrier layer may be also disposed between the second portion P 2  and the third portion P 3  and may extend in the X-axis direction therebetween. The barrier layer between the second portion P 2  and the third portion P 3  may be a separate barrier layer from the barrier layer between the first portion P 1  and the second portion P 2 , or the two barrier layers may be part of a single, uniform layer. In some example embodiments, as compared with a case, in which the first portion P 1  in the M 3  layer and the third portion P 3  in the M 2  layer are connected to each other through at least one via in the V 2  layer instead of the second portion P 2  in the V 2  layer extending in the X-axis direction unlike the example of  FIG.  6 D , the multi-layer conducting line  60   d  of  FIG.  6 D  may have a reduced resistance due to the second portion P 2  extending in the X-axis direction. The barrier layer between the second portion P 2  and the third portion P 3  may be configured to reduce or prevent a material included in the third portion P 3  and/or a material included in the second portion P 2  from diffusing when the third portion P 3  and/or the second portion P 2  is formed. The barrier layer between the first portion P 1  and the second portion P 2  may be configured to reduce or prevent a material included in the first portion P 1  and/or a material included in the second portion P 2  from diffusing when the first portion P 1  and/or the second portion P 2  is formed. 
     Referring to  FIG.  6 E , the multi-layer conducting line  60   e  may include the first portion P 1  extending in the X-axis direction in the M 3  layer, the second portion P 2  extending in the X-axis direction in the V 2  layer, and the third portion P 3  extending in the X-axis direction in the M 2  layer. Similarly to the multi-layer conducting line  60   d  of  FIG.  6 D , the first portion P 1 , the second portion P 2 , and the third portion P 3  of  FIG.  6 E  may be separately formed from each other, and at least two of the first portion P 1 , the second portion P 2 , and the third portion P 3  may have different lengths from each other. In some example embodiments, as shown in  FIG.  6 E , the first portion P 1  of the M 3  layer and the third portion P 3  of the M 2  layer may have the length L that is the same as that of the multi-layer conducting line  60   e , whereas the second portion P 2  of the V 2  layer may have a length L′ that is less than the length L of the multi-layer conducting line  60   e.    
       FIGS.  7 A and  7 B  are diagrams showing examples of the multi-layer conducting lines  60   a  and  60   b  according to some example embodiments. In detail,  FIG.  7 A  shows an example of a cross-section taken along a plane perpendicular to the X-axis direction in which the multi-layer conducting line  60   a  of  FIG.  6 A  extends, and  FIG.  7 B  shows an example of a cross-section taken along a plane perpendicular to the X-axis direction in which the multi-layer conducting line  60   b  of  FIG.  6 B  extends. Hereinafter, redundant descriptions about  FIGS.  7 A and  7 B  will be omitted. 
     Referring to  FIG.  7 A , the multi-layer conducting line  60   a  may include the first portion P 1  extending in the X-axis direction in the M 3  layer, the second portion P 2  extending in the X-axis direction in the V 2  layer, and the third portion P 3  extending in the X-axis direction in the M 2  layer. As described above with reference to  FIG.  6 A , the first portion P 1 , the second portion P 2 , and the third portion P 3  of the multi-layer conducting line  60   a  may be integrally formed with one another. Accordingly, the first portion P 1 , the second portion P 2 , and the third portion P 3  in the multi-layer conducting line  60   a  may include the same material, e.g., metal, and boundaries among the first portion P 1 , the second portion P 2 , and the third portion P 3  may include the same metal. In some example embodiments, the first portion P 1 , the second portion P 2 , and the third portion P 3  of the multi-layer conducting line  60   a  may have substantially the same widths W as shown in  FIG.  7 A . 
     Referring to  FIG.  7 B , the multi-layer conducting line  60   b  may include the first portion P 1  extending in the X-axis direction in the M 3  layer, the second portion P 2  extending in the X-axis direction in the V 2  layer, and the third portion P 3  extending in the X-axis direction in the M 2  layer. As described above with reference to  FIG.  6 B , the first portion P 1  and the second portion P 2  may be integrally formed with each other, and the third portion P 3  may not be integrally formed with the first portion P 1  and the second portion P 2 . Accordingly, as shown in  FIG.  7 B , the boundary between the first portion P 1  and the second portion P 2  in the upper portion of the multi-layer conducting line  60   b  may include the same metal as those of the first and second portions P 1  and P 2 , and on the contrary, a barrier layer may be disposed on the boundary between the second portion P 2  and the third portion P 3  in the lower portion of the multi-layer conducting line  60   b . Accordingly, as shown in  FIG.  7 B , a multi-layer conducting line  60   b  may include a barrier layer  61   b  and/or  62   b  between the first portion P 1  and the third portion P 3 . In some example embodiments, the barrier layer  61   b  and/or  62   b , which may each at least partially extend in the X-axis direction (or second direction) between the second portion P 2  and the third portion P 3 , may be configured to reduce or prevent a material included in the third portion P 3  and/or a material included in the second portion P 2  from diffusing when the third portion P 3  and/or the second portion P 2  is formed. 
     In some example embodiments, the first portion P 1 , the second portion P 2 , and the third portion P 3  of the multi-layer conducting line  60   b  may have different widths from one another. In some example embodiments, as shown in  FIG.  7 B , the first portion P 1  of the M 3  layer and the third portion P 3  of the M 2  layer may approximately have the first width W 1 , and the second portion P 2  of the V 2  layer may have the second width W 2 . The second width W 2  may be less than the first width W 1 . Lengths of the portions included in the multi-layer conducting line may be determined according to the semiconductor process. 
       FIGS.  8 A and  8 B  are diagrams showing examples of multi-layer conducting lines  80   a  and  80   b  according to some example embodiments. In detail,  FIGS.  8 A and  8 B  show the multi-layer conducting lines  80   a  and  80   b  each including portions that have a length L in the X-axis direction and extend together in the X-axis direction respectively in four successive layers. It would be appreciated from  FIGS.  8 A and  8 B  that the multi-layer conducting lines as shown in  FIGS.  8 A and  8 B  having the structures may be formed according to the semiconductor process, and multi-layer conducting lines including the portions extending together in three successive four or more layers in a different structure from those of  FIGS.  8 A and  8 B  may be implemented. Hereinafter, redundant descriptions about  FIGS.  8 A and  8 B  will be omitted. 
     Referring generally to both  FIGS.  8 A and  8 B , an integrated circuit (e.g., the integrated circuit as shown in  FIG.  2   ) may further include a V 3  layer (e.g., a second via layer) that includes a plurality of second vias, where V 3  layer is adjacent to the M 3  layer (or second wiring layer) in the Z-axis direction (or first direction), such that the M 3  layer is between the V 3  layer and the V 2  layer. Referring to  FIG.  8 A , the multi-layer conducting line  80   a  may include the first portion P 1  extending in the X-axis direction in the M 2  layer, the second portion P 2  extending in the X-axis direction in the V 2  layer, the third portion P 3  extending in the X-axis direction in the M 3  layer, and the fourth portion P 4  extending in the X-axis direction (or second direction) in the V 3  layer. As shown in  FIG.  8 A , the first portion P 1 , the second portion P 2 , the third portion P 3 , and the fourth portion P 4  may be integrally formed with one another, and in some example embodiments, the multi-layer conducting line  80   a  may be formed by the damascene process. As shown in  FIG.  8 A , an interlayer insulator IL may be disposed on an upper surface of the multi-layer conducting line  80   a , and accordingly, the multi-layer conducting line  80   a  may be insulated from patterns formed in a wiring layer above the V 3  layer. 
     Referring to  FIG.  8 B , the multi-layer conducting line  80   b  may include the first portion P 1  extending in the X-axis direction in the M 2  layer, the second portion P 2  extending in the X-axis direction in the V 2  layer, the third portion P 3  extending in the X-axis direction in the M 3  layer, and the fourth portion P 4  extending in the X-axis direction in a V 3  layer. As shown in  FIG.  8 B , the first portion P 1  and the second portion P 2  may be integrally formed with each other in the lower portion of the multi-layer conducting line  80   b , and the third portion P 3  and the fourth portion P 4  may be integrally formed with each other in the upper portion of the multi-layer conducting line  80   b . Accordingly, a barrier layer may be disposed between the second portion P 2  of the V 2  layer and the third portion P 3  of the M 3  layer. Similarly to the multi-layer conducting line  80   a  of  FIG.  8 A , an interlayer insulator IL may be disposed on an upper surface of the multi-layer conducting line  80   b  of  FIG.  8 B . 
       FIG.  9    is a block diagram of a memory device  90  according to some example embodiments, and  FIG.  10    is a diagram partially showing a layout of the memory device  90  of  FIG.  9   , according to some example embodiments. In some example embodiments, the memory device  90  may be an example of the integrated circuit  10  of  FIG.  1   . A series of memory cells C 1 , . . . , Cn, extending in the X-axis direction and thus at least partially overlapping each other in the X-axis direction, may correspond to the plurality of unit circuits U 1 , . . . , Un of  FIG.  1   , where the memory cells C 1 , . . . , Cn are each configured to store at least one bit of data, and a plurality of word lines WLs in the memory device  90  may be implemented as multi-layer conducting lines, such that at least one multi-layer conducting line ML that is electrically connected to control electrodes of transistors included in the series of memory cells C 1 , . . . , Cn is at least a part of a word line WL configured to select one or more memory cells of the memory cells C 1 , . . . , Cn. 
     Referring to  FIG.  9   , the memory device  90  may include a memory cell array  92 , a row decoder  94 , and a page buffer  96 . The memory device  90  may receive a command and address from outside, and may receive or output data. In some example embodiments, the memory device  90  may receive a command such as a write command and a read command, and an address corresponding to the command. The memory device  90  may receive data in response to a write command and may output data in response to a read command. The memory device  90  may be packaged as an independent memory device or may be included in a semiconductor package such as a system-on-chip or a processor. 
     The memory cell array  92  may include a plurality of memory cells. In some example embodiments, as shown in  FIG.  9   , the memory cell array  92  may include a series of memory cells C 1 , . . . , Cn that are disposed in a certain direction as static random access memory (SRAM) cells (n is 1 or greater integer). The first memory cell C 2  may include a first inverter INV 1  and a second inverter INV 2  that are cross-connected, and a first transistor T 1  and a second transistor T 2  that connect the first inverter INV 1  and the second inverter INV 2  electrically to a first bit line pair BL 11  and BL 21  during a write operation and a read operation. Although  FIG.  9    shows the SRAM cell as an example, it would be appreciated that the word lines including multi-layer conducting lines may be applied to memories different from the SRAM, e.g., flash memory, dynamic RAM (DRAM), resistive RAM (RRAM), phase-change RAM (PRAM), etc. 
     The memory cell array  92  may be connected to the row decoder  94  via the plurality of word lines WLs, and may be connected to the page buffer  96  via a plurality of bit lines BLs. The series of memory cells C 1 , . . . , Cn included in the memory cell array  92  may be connected to a k-th word line WLk among the plurality of word lines WLs, and the series of memory cells C 1 , . . . , Cn connected to one word line or data stored in the series of memory cells C 1 , . . . , Cn may be referred to as a page. As shown in  FIG.  9   , the k-th word line WLk including the multi-layer conducting line may be connected (e.g., electrically connected) to control electrodes (e.g., gate electrodes) of the first transistor T 1  and the second transistor T 2  included in the first memory cell C 1 . Similarly, the k-th word line WLk may be connected (e.g., electrically connected) to control electrodes of transistors included in the second through nth memory cells C 2  . . . Cn. Accordingly, it will be understood that the multi-layer conducting line may be electrically connected to control electrodes of transistors included in the plurality of memory cells C 1  . . . Cn, which may be unit circuits. 
     The row decoder  94  may activate the k-th word line WLk among the plurality of word lines WLs, in order to select a series of memory cells C 1 , . . . , Cn from among the plurality of memory cells included in the memory cell array  92 . In some example embodiments, the row decoder  94  may activate the k-th word line WLk by increasing a voltage level of the k-th word line WLk. That is, the row decoder  94  may correspond to the control circuit  12  of  FIG.  1   . The page buffer  96  may provide the plurality of bit lines BLs with signals corresponding to data to be written in the selected series of memory cells C 1 , . . . , Cn, or may sense signals corresponding to data stored in the series of memory cells C 1 , . . . , Cn selected by the row decoder  94  from the plurality of bit lines BLs. 
     The k-th word line WLk including the multi-layer conducting line may have a reduced resistance as described above with reference to the accompanying drawings, and accordingly, a difference between time points at which the signals applied by the row decoder  94  to the k-th word line WLk, e.g., high level voltage (or low level voltage), reach the first memory cell C 1  and the n-th memory cell Cn may be reduced, and accordingly, the writing speed and reading speed onto/from the memory device  90  may be improved. Also, due to the reduced resistance of the k-th word line WLk, the k-th word line WLk may have a width that is less than that of a case in which the word line does not include the multi-layer conducting line, and examples in which the k-th word line WLk has the reduced width will be described below with reference to  FIG.  10   . 
     Referring to the left in  FIG.  10   , a first line L 1  and a second line L 2 , to which a negative supply voltage (VSS) (or ground voltage) is applied, on boundaries facing each other in the Y-axis direction from among boundaries of a first memory cell C 1 ′ may extend in the X-axis direction, and the k-th word line WLk′ not including the multi-layer conducting line may extend between the first and second lines L 1  and L 2 . In order to supply stabilized negative supply voltage (VSS) to a series of memory cells including the first memory cell C 1 ′, the first line L 1  and the second line L 2  providing the negative supply voltage (VSS) may be disposed as shown in  FIG.  10   . The first line L 1  and the second line L 2  may have a first width W 1 , and the k-th word line WLk′ not including the multi-layer conducting line may have a second width W 2 . As described above, when the k-th word lines WLk′ includes the multi-layer conducting line, the k-th word line WLk′ may have a width less than the second width W 2 , and in  FIG.  10   , ‘case A’ and ‘case B’ are examples, in which the k-th word line WLk′ include the multi-layer conducting line. 
     Referring to ‘case A’ of  FIG.  10   , a width W 1   a  of a first line L 1   a  and a second line L 2   a  that supply the negative supply voltage (VSS) to a series of memory cells including a first memory cell C 1   a  may be maintained (W 1   a =W 1 ). However, a distance between a k-th word line WLka and the first line L 1   a  may increase and a distance between the k-th word lines WLk 1  and the second line L 2   a  may increase due to a reduced width W 2   a  of the k-th word line WLka (W 2   a &lt;W 2 ). In some example embodiments, a distance S of the k-th word line WLk′ shown in the left side of  FIG.  10    respectively from the first line L 1  and the second line L 2  may be equal to a minimum distance between patterns in the M 2  layer, and a distance Sa of the k-th word line WLka from the first line L 1   a  and the second line L 2   a  in ‘case A’ of  FIG.  10    may be greater than the minimum distance between patterns in the M 2  layer. Accordingly, the capacitance generated by the k-th word line WLka with the first line L 1   a  and the second line L 2   a  may be reduced, and thus, a delay occurring on the k-th word line WLka may be further reduced. 
     Referring to ‘case B’ of  FIG.  10   , due to a reduced width W 2   b  of the k-th word line WLka (W 2   b &lt;W 2 ), a width W 1   b  of a first line L 1   n  and a second line L 2   b  providing a first memory cell C 1   b  with the negative supply voltage VSS may increase (W 1   b &gt;W 1 ). Accordingly, resistances of the first line L 1   b  and the second line L 2   b  may be reduced, and accordingly, the negative supply voltage VSS may be provided reliably to a series of memory cells including the first memory cell C 1   b.    
       FIG.  11    is a block diagram of an image sensor  110  according to some example embodiments. In some example embodiments, the image sensor  110  may be an example of the integrated circuit  10  of  FIG.  1   . A series of pixels X 1 , . . . , Xn, extending in the X-axis direction and thus at least partially overlapping each other in the X-axis direction, may correspond to the plurality of unit circuits U 1 , . . . , Un of  FIG.  1   , and at least some of control lines RSs, TGs, and SELs for controlling the plurality of pixels in the image sensor  110  may include multi-layer conducting lines, such that at least one multi-layer conducting line ML that is electrically connected to control electrodes of transistors included in the pixels X 1 , . . . , Xn is at least a part of a control line configured to communicate control signals for controlling operations of the pixels X 1 , . . . , Xn and thus the multi-layer conducting line may be configured to receive a control signal for controlling operations of the plurality of pixels X 1 , . . . , Xn. 
     Referring to  FIG.  11   , the image sensor  110  may include a pixel array  112 , a row driver  114 , and a read circuit  116 . The pixel array  112  may be connected to the row driver  114  via the plurality of control lines, that is, a plurality of reset lines RSs, a plurality of transfer lines TGs, and a plurality of selection lines SELs, and may be connected to the read circuit  116  via a plurality of output lines OLs. The row driver  114  may simultaneously or sequentially activate some of the plurality of reset lines RSs, the plurality of transfer lines TGs, and the plurality of selection lines SELs to control the plurality of pixels included in the pixel array  112 , and the read circuit  116  may detect light intensity sensed by the pixel array  112  by sensing a voltage and/or current of the output lines OLs. 
     The pixel array  112  may include the plurality of pixels. In some example embodiments, the pixel array  112  may include a series of pixels X 1 , . . . , Xn each having a 4-transistor (4T) structure as shown in  FIG.  11    (n is 1 or greater integer). That is, the first pixel X 1  may include four transistors T 3  to T 6  and a photo-detecting device PD. Although  FIG.  11    shows the pixel having the 4T structure, it would be appreciated that the control lines including the multi-layer conducting lines may be applied to an image sensor including pixels of another structure, e.g.,  6 T structure. As shown in  FIG.  11   , a k-th transfer line TGk may be connected to a control electrode (or gate electrode) of a transfer transistor T 3 , a k-th reset line RSk may be connected to a control electrode of a reset transistor T 5 , and a k-th selection line SELk may be connected to a control electrode of a selection transistor T 6 . Accordingly, it will be understood that the multi-layer conducting line may be electrically connected to control electrodes of transistors included in the plurality of pixels X 1  . . . Xn, which may be unit circuits. The multi-layer conducting line ML that is electrically connected to control electrodes of transistors included in the plurality of pixels X 1  . . . Xn may be configured to receive a control signal for controlling operations of the plurality of pixels X 1  . . . Xn. 
     Since at least some of the plurality of control lines include multi-layer conducting lines, operations of the image sensor  110  may be improved. In some example embodiments, when the plurality of transfer lines TGs include the multi-layer conducting lines, a difference between a period, in which the first pixel X 1  senses light, and a period, in which an n-th pixel Xn senses light, may be reduced, and accordingly, accuracy of an image generated by the image sensor  110  may be improved. Also, when the plurality of selection lines SELs include the multi-layer conducting lines, a difference between a time point at which the first pixel X 1  outputs a signal to a first output line OL 1  and a time point at which the n-th pixel Xn outputs a signal to an n-th output line OLn may be reduced, and accordingly, a reading speed of the read circuit  116  may increase and an image capturing speed of the image sensor  110  may also increase. 
       FIG.  12    is a block diagram of a display apparatus  120  according to some example embodiments. In some example embodiments, the display apparatus  120  (or display panel  122 ) may be an example of the integrated circuit  10  of  FIG.  1   . A series of pixels X 1 ′, . . . , Xn′, extending in the X-axis direction and thus at least partially overlapping each other in the X-axis direction, may correspond to the unit circuits U 1 , . . . , Un of  FIG.  1    and may each be configured to emit light, and a plurality of scan lines SLs for controlling the plurality of pixels in the display apparatus  120  may include multi-layer conducting lines. Accordingly, at least one multi-layer conducting line ML that is electrically connected to control electrodes of transistors included in the pixels X 1 ′, . . . , Xn′ is at least a part of a scan line SL configured to select one or more pixels of the pixels X 1 ′, . . . , Xn′. 
     Referring to  FIG.  12   , the display apparatus  120  may include the display panel  122 , a scan driver  124 , and a data driver  126 . The display panel  122  may be connected to the scan driver  124  via the plurality of scan lines SLs, and may be connected to the data driver  126  via a plurality of data lines DLs. The scan driver  124  may activate one of the plurality of scan lines SLs for selecting a series of pixels from among the plurality of pixels included in the display panel  122 , and the data driver  126  may provide the plurality of data lines DLs with a voltage and/or a current according to an intensity of light that is to be emitted from the series of pixels that are selected by the scan driver  124 . 
     The display panel  122  may include the plurality of pixels. In some example embodiments, the display panel  122  may include a series of pixels X 1 ′, . . . , Xn′ each including a light-emitting diode (LED) (n is 1 or greater integer). That is, a first pixel X 1 ′ may include two transistors T 7  and T 8 , a capacitor CAP, and an LED LD. Although  FIG.  12    shows the pixels including the LED, it would be appreciated that the plurality of scan lines SLs including the multi-layer conducting lines may be also applied to a display panel including other light-emitting elements than the LED. As shown in  FIG.  12   , a k-th scan line SLk may be connected to a control electrode (or a gate electrode) of the switching transistor T 7 . Accordingly, it will be understood that the multi-layer conducting line may be electrically connected to control electrodes of transistors included in the plurality of pixels X 1 ′ . . . Xn′, which may be unit circuits. 
     Since the plurality of scan lines SLs include the multi-layer conducting lines, operations of the display apparatus  120  may be improved. In some example embodiments, a difference between a time point of selecting the first pixels X 1 ′ and a time point of selecting the n-th pixel Xn′ may be reduced, and accordingly, quality of an image output from the display panel  122  may be improved and a speed of updating images in the display panel  122  may increase. 
       FIG.  13    is a block diagram of a system-on-chip (SoC)  130  according to some example embodiments. The SoC  130  may be an example of the integrated circuit  10  of  FIG.  1   , and may include a multi-layer conducting line according to some example embodiments. The SoC  130  implements complicated functional blocks such as an IP (intellectual property) performing various functions in one chip, and multi-layer conducting lines each including portions extending in two or more successive layers according to some example embodiments may be included in each functional block of the SoC  130 . Accordingly, a delay occurring in wirings may be reduced while achieving high spatial efficiency, the SoC  130  may have a high integration and a high operating speed. 
     Referring to  FIG.  13   , the SoC  130  may include a modem  132 , a display controller  133 , a memory  134 , an external memory controller  135 , a central processing unit (CPU)  136 , a transaction circuitry  137 , a power management integrated circuit (PMIC)  138 , and a graphics processing unit (GPU)  139 , and the functional blocks in the SoC  130  may communicate with one another via a system bus  131 . One or more of the elements included in the SoC  130 , including the modem  132 , display controller  133 , memory  134 , external memory controller  135 , central processing unit (CPU)  136 , transaction circuitry  137 , power management integrated circuit (PMIC)  138 , and graphics processing unit (GPU)  139 , and the functional blocks in the SoC  130 , may be implemented by and/or substituted with one or more instances of processing circuitry such as hardware including logic circuits; a hardware/software combination such as a processor executing software; or a combination thereof. For example, the SoC  130  more specifically may include, but is not limited to, a central processing unit (CPU), an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, a field programmable gate array (FPGA), a System-on-Chip (SoC), a programmable logic unit, a microprocessor, application-specific integrated circuit (ASIC), etc. that is/are configured to implement the functionality of some or all of the elements of the SoC as shown in  FIG.  14    and/or some or all of the functional blocks in the SoC. 
     The CPU  136  that controls overall operations of the SoC  130  may control operations of other functional blocks (e.g.,  132 ,  133 ,  134 ,  135 ,  137 ,  138 , and  139 ). The modem  132  may demodulate a signal received from outside of the SoC  130  or modulate a signal generated in the SoC  130 , and then, may transmit the signal to outside. The external memory controller  135  may control an operation of transmitting/receiving data to/from an external memory device connected to the SoC  130 . In some example embodiments, a program and/or data stored in the external memory device may be provided to the CPU  136  or the GPU  139  under the control of the external memory controller  135 . The GPU  139  may execute program instructions regarding processing of graphics. The GPU  139  may receive graphic data via the external memory controller  135  or may transmit graphic data processed by the GPU  139  to outside of the SoC  130  via the external memory controller  135 . Transaction circuitry  137  may monitor data transaction of each functional block, and the PMIC  138  may control electric power supplied to each functional block according to the control of the transaction circuitry  137 . The display controller  133  controls a display (or display apparatus) on an outer portion of the SoC  130  to transfer the data generated in the SoC  130  to the display. 
     The memory  134  may include non-volatile memory such as electrically erasable programmable read-only memory (EEPROM), flash memory, phase change RAM (PRAM), resistance RAM (RRAM), nano floating gate memory (NFGM), polymer RAM (PoRAM), magnetic RAM (MRAM), ferroelectric RAM (FRAM), etc. or volatile memory such as dynamic RAM (DRAM), static RAM (SRAM), mobile DRAM, double data rate synchronous DRAM (DDR SDRAM), low power DDR (LPDDR) SDRAM, graphic DDR (GDDR) SDRAM, Rambus DRAM (RDRAM), etc. In some example embodiments, as described above with reference to  FIG.  9   , etc., a plurality of word lines for respectively selecting some of the plurality of memory cells included in the memory  134  may include multi-layer conducting lines. 
     While the inventive concepts have been particularly shown and described with reference to embodiments thereof, it will be understood that various changes in form and details may be made therein without departing from the spirit and scope of the following claims.