Patent Publication Number: US-2022216150-A1

Title: Semiconductor devices and methods of fabricating the same

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This U.S. non-provisional patent application claims priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2021-0001672, filed on Jan. 6, 2021, in the Korean Intellectual Property Office, the entire contents of which are hereby incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     The present disclosure relates to semiconductor devices and to methods of fabricating the same. In particular, the present disclosure relates to semiconductor devices including field effect transistors, and to methods of fabricating the same. 
     Some semiconductor devices may include an integrated circuit having metal-oxide-semiconductor field-effect transistors (MOSFETs). To meet increasing demand for semiconductor devices with small pattern sizes and reduced design rules, MOSFETs are being scaled down, and in some instances are being aggressively scaled down. The scaling down of MOSFETs is not without drawbacks, and it may lead to deterioration in operational properties of semiconductor devices. A variety of studies are being conducted to consider techniques to overcome technical limitations associated with the scaling-down of semiconductor devices, and to realize high performance semiconductor devices. 
     SUMMARY 
     Aspects of the present disclosure provide semiconductor devices with improved electric characteristics, and methods of fabricating the same. 
     According to some embodiments of the inventive concepts, a semiconductor device may include a logic cell on a substrate and a first metal layer on the logic cell. The logic cell may include a PMOSFET region and an NMOSFET region. The first metal layer may include a first power line and a second power line that extend in a first direction and are parallel to each other, and a first lower interconnection line, a second lower interconnection line, and a third lower interconnection line, which are respectively arranged on a first interconnection track, a second interconnection track, and a third interconnection track that extend in parallel in the first direction between the first power line and the second power line, with the second interconnection track between the first and third interconnection tracks. The first to third interconnection tracks may be extended in the first direction to be parallel to each other. The first lower interconnection line may include a first interconnection line and a second interconnection line spaced apart from each other in the first direction by a first distance, and the third lower interconnection line may include a third interconnection line and a fourth interconnection line spaced apart from each other in the first direction by a second distance smaller than the first distance. The first interconnection line may have a first end with a first curvature that faces the second interconnection line, and the third interconnection line may have a second end with a second, different curvature that faces the fourth interconnection line. The second lower interconnection line may extend in the first direction with a uniform linewidth in a second direction, including at a first portion across from the first distance between the first and second interconnection lines. 
     According to some embodiments of the inventive concepts, a semiconductor device may include a logic cell on a substrate and a first metal layer on the logic cell. The logic cell may include a PMOSFET region and an NMOSFET region. The first metal layer may include a first power line and a second power line, which extend in a first direction and are parallel to each other, and first to fifth lower interconnection lines, which are respectively disposed on first to fifth interconnection tracks that are sequentially defined between the first power line and the second power line and extend in the first direction parallel to each other. The first to fifth interconnection tracks may be arranged, at a constant pitch, in a second direction crossing the first direction. Linewidths of the first, third, and fifth lower interconnection lines may be equal to a first width, and linewidths of the second and fourth lower interconnection lines may be equal to a second width. The first width may be different from the second width. 
     According to some embodiments of the inventive concepts, a semiconductor device may include an active pattern on a substrate, a device isolation layer in a trench that defines the active pattern, a source/drain pattern on the active pattern and a channel pattern connected to the source/drain pattern, the channel pattern including a first semiconductor pattern, a second semiconductor pattern, and a third semiconductor pattern, which are sequentially stacked to be spaced apart from each other, a gate electrode that extends and crosses the channel pattern, the gate electrode including a first portion between the active pattern and the first semiconductor pattern, a second portion between the first semiconductor pattern and the second semiconductor pattern, a third portion between the second semiconductor pattern and the third semiconductor pattern, and a fourth portion on the third semiconductor pattern, a gate insulating layer between the channel pattern and the gate electrode, gate spacers on opposite side surfaces of the fourth portion of the gate electrode, respectively, a gate capping pattern on a top surface of the gate electrode, a first interlayer insulating layer on the gate capping pattern, an active contact that penetrates the first interlayer insulating layer and coupled to the source/drain pattern, a gate contact that penetrates the first interlayer insulating layer and is coupled to the gate electrode, a second interlayer insulating layer on the first interlayer insulating layer, a first metal layer in the second interlayer insulating layer and connected to the active contact and the gate contact, a third interlayer insulating layer on the second interlayer insulating layer, and a second metal layer in the third interlayer insulating layer. The first metal layer may include a first power line and a second power line, which extend in a first direction and are spaced apart from each other, and a first lower interconnection line, a second lower interconnection line, and a third lower interconnection line, which are respectively arranged on a first interconnection track, a second interconnection track, and a third interconnection track that extend in parallel between the first power line and the second power line with the second interconnection track between the first and third interconnection tracks. The first lower interconnection line may include a first interconnection line and a second interconnection line, which are spaced apart from each other in the first direction by a first distance, and the third lower interconnection line may include a third interconnection line and a fourth interconnection line, which are spaced apart from each other in the first direction by a second distance smaller than the first distance. The first interconnection line may have a first end with a first curvature that faces the second interconnection line, and the third interconnection line may have a second end with a second, different curvature that faces the fourth interconnection line. The second lower interconnection line may extend with a uniform linewidth in a second direction, including at a first portion, which is across from the first distance between the first and second interconnection lines. 
     According to some embodiments of the inventive concepts, a method of fabricating a semiconductor device may include forming an etch target layer on a substrate, forming a mold layer on the etch target layer, forming first line patterns, which extend in a first direction to be parallel to each other, on the mold layer, forming spacers on side surfaces of the first line patterns, forming second line patterns in spaces between the spacers, the second line patterns extending in the first direction, and parallel to each other, performing a first photolithography process on the second line patterns to form a first line and a second line from a first one of the second line patterns, the first line and the second line being spaced apart from each other in the first direction by a first distance, performing a patterning process to form two lines spaced apart from each other by the first distance, and performing a second photolithography process on the second line patterns to form a third line and a fourth line from a second one of the second line patterns. The third line and fourth line may be spaced apart from each other in the first direction by a second distance, and the first distance may be larger than the second distance. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a plan view illustrating a semiconductor device according to some embodiments of the inventive concepts. 
         FIGS. 2A to 2D  are sectional views taken along lines A-A′, B-B′, C-C′ and D-D′, respectively, of  FIG. 1 . 
         FIG. 3  is a plan view illustrating first to third lower interconnection lines, which may be on first to third interconnection tracks of  FIG. 1 . 
         FIG. 4  is a plan view illustrating a structure according to a comparative example of  FIG. 3 . 
         FIGS. 5, 7, 9, 11, 13, 15, 17, and 19  are plan views illustrating a method of fabricating a first metal layer, according to some embodiments of the inventive concepts. 
         FIGS. 6, 8A, 10A, 12A, 14A, 16A, 18A, and 20A  are sectional views taken along lines I-I′ of  FIGS. 5, 7, 9, 11, 13, 15, 17, and 19 , respectively. 
         FIGS. 8B, 10B, 12B, 14B, 16B, 18B, and 20B  are sectional views taken along lines II-II′ of  FIGS. 7, 9, 11, 13, 15, 17, and 19 , respectively. 
         FIGS. 21, 23, 25, 27, 29, and 31  are plan views illustrating a method of fabricating a first metal layer, according to some embodiments of the inventive concepts. 
         FIGS. 22A, 24A, 26A, 28A, 30A, and 32A  are sectional views taken along lines I-I′ of  FIGS. 21, 23, 25, 27, 29, and 31 , respectively. 
         FIGS. 22B, 24B, 26B, 28B, 30B, and 32B  are sectional views taken along lines II-II′ of  FIGS. 21, 23, 25, 27, 29, and 31 , respectively. 
         FIGS. 33 and 34  are plan views, each of which illustrates first to third lower interconnection lines of  FIG. 1 , according to some embodiments of the inventive concepts. 
         FIGS. 35A to 35D  are sectional views, which are respectively taken along lines A-A′, B-B′, C-C′, and D-D′ of  FIG. 1  to illustrate a semiconductor device according to some embodiments of the inventive concepts. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is a plan view illustrating a semiconductor device according to some embodiments of the inventive concepts.  FIGS. 2A to 2D  are sectional views taken along lines A-A′, B-B′, C-C′ and D-D′, respectively, of  FIG. 1 . 
     Referring to  FIGS. 1 and 2A to 2D , a plurality of logic cells LC 1  and LC 2  may be provided on a substrate  100 . The substrate  100  may be a semiconductor substrate that is formed of or includes silicon, germanium, silicon-germanium, a compound semiconductor material, or the like. In some embodiments, the substrate  100  may be a silicon substrate. 
     As an example, the logic cells LC 1  and LC 2  may include a first logic cell LC 1  and a second logic cell LC 2 , which are adjacent to each other in a second direction D 2 . Logic transistors of a logic circuit may be on each of the first and second logic cells LC 1  and LC 2 . Each of the first and second logic cells LC 1  and LC 2  may include MOSFET regions of a first and second type, e.g., a PMOSFET region PR and an NMOSFET region NR. The PMOSFET and NMOSFET regions PR and NR may be spaced apart from each other in a first direction D 1 . 
     As best seen in  FIG. 2C , a first active pattern AP 1  and a second active pattern AP 2  may be defined by a trench TR, which may be formed in an upper portion of the substrate  100 . The first and second active patterns AP 1  and AP 2  may be provided on the PMOSFET and NMOSFET regions PR and NR, respectively. The first and second active patterns AP 1  and AP 2  may extend in the second direction D 2 . The first and second active patterns AP 1  and AP 2  may be vertically protruding portions of the substrate  100 . 
     A device isolation layer ST may fill the trench TR. The device isolation layer ST may include a silicon oxide layer. The device isolation layer ST may not cover first and second channel patterns CH 1  and CH 2 , which will be described below. 
     The first channel pattern CH 1  may be provided on the first active pattern AP 1 . The second channel pattern CH 2  may be provided on the second active pattern AP 2 . Each of the first channel pattern CH 1  and the second channel pattern CH 2  may include a first semiconductor pattern SP 1 , a second semiconductor pattern SP 2 , and a third semiconductor pattern SP 3 , which are sequentially stacked. The first to third semiconductor patterns SP 1 , SP 2 , and SP 3  may be spaced apart from each other in a vertical direction (i.e., a third direction D 3 ). 
     Each of the first to third semiconductor patterns SP 1 , SP 2 , and SP 3  may be formed of or include silicon (Si), germanium (Ge), or silicon-germanium (SiGe). In some embodiments, each of the first to third semiconductor patterns SP 1 , SP 2 , and SP 3  may be formed of or include crystalline silicon. 
     As best seen in  FIG. 2A , a plurality of first source/drain patterns SD 1  may be provided on the first active pattern AP 1 . A plurality of first recesses RS 1  may be formed in an upper portion of the first active pattern AP 1 . The first source/drain patterns SD 1  may be provided in the first recesses RS 1 , respectively. The first source/drain patterns SD 1  may be impurity regions of a first conductivity type (e.g., p-type). The first channel pattern CH 1  may be interposed between adjacent first source/drain patterns SD 1 . In other words, two adjacent first source/drain patterns SD 1  may be connected to each other by the stacked first to third semiconductor patterns SP 1 , SP 2 , and SP 3  of the first channel pattern CH 1  therebetween. At least some of the first source/drain patterns SD 1  may be connected to two of the first channel patterns CH 1 . 
     A plurality of second source/drain patterns SD 2  may be provided on the second active pattern AP 2 . A plurality of second recesses RS 2  may be formed in an upper portion of the second active pattern AP 2 . The second source/drain patterns SD 2  may be provided in the second recesses RS 2 , respectively. The second source/drain patterns SD 2  may be impurity regions of a second conductivity type (e.g., n-type). The second channel pattern CH 2  may be interposed between adjacent second source/drain patterns SD 2 . In other words, two adjacent second source/drain patterns SD 2  may be connected to each other by the stacked first to third semiconductor patterns SP 1 , SP 2 , and SP 3  of the second channel pattern CH 2 . At least some of the second source/drain patterns SD 1  may be connected to two of the second channel patterns CH 2 . 
     The first and second source/drain patterns SD 1  and SD 2  may be epitaxial patterns, which may be formed by a selective epitaxial growth (SEG) process. As an example, each of the first and second source/drain patterns SD 1  and SD 2  may have a top surface that is located at substantially the same level from the substrate  100  as a top surface of the third semiconductor pattern SP 3 . However, in some embodiments, the top surface of each of the first and second source/drain patterns SD 1  and SD 2  may be higher than the top surface of the third semiconductor pattern SP 3 , or in other words farther from the substrate  100  than the top surface of the third semiconductor pattern SP 3 . 
     The first source/drain patterns SD 1  may include a semiconductor material (e.g., SiGe) having a lattice constant greater than that of the substrate  100 . In some embodiments, two adjacent first source/drain patterns SD 1  may exert a compressive stress on the first channel patterns CH 1  therebetween. The second source/drain patterns SD 2  may be formed of or include the same semiconductor material (e.g., Si) as the substrate  100 . 
     Each of the first source/drain patterns SD 1  may include a first semiconductor layer SEL 1  and a second semiconductor layer SEL 2 , which may be sequentially stacked. A sectional shape of the first source/drain pattern SD 1  taken parallel to the second direction D 2  will be described in greater detail herein. 
     The first semiconductor layer SEL 1  may cover an inner surface of a first recess RS 1 . The first semiconductor layer SEL 1  may have a decreasing thickness in an upward direction. For example, the thickness of the first semiconductor layer SEL 1 , which is measured in the third direction D 3  at the bottom level of the first recess RS 1 , may be larger than the thickness of the first semiconductor layer SEL 1 , which is measured in the second direction D 2  at the top level of the first recess RS 1 . The first semiconductor layer SEL 1  may have a ‘U’-shaped section, due to a sectional profile of the first recess RS 1 . 
     The second semiconductor layer SEL 2  may fill a remaining space of the first recess RS 1  excluding the first semiconductor layer SEL 1 . A volume of the second semiconductor layer SEL 2  may be larger than a volume of the first semiconductor layer SEL 1 . In other words, a ratio of a volume of the second semiconductor layer SEL 2  to a total volume of the first source/drain pattern SD 1  may be greater than a ratio of a volume of the first semiconductor layer SEL 1  to the total volume of the first source/drain pattern SD 1 . 
     Each of the first and second semiconductor layers SEL 1  and SEL 2  may be formed of or include silicon-germanium (SiGe). In greater detail, the first semiconductor layer SEL 1  may have a relatively low germanium concentration. In some embodiments, the first semiconductor layer SEL 1  may contain only silicon (Si) and not germanium (Ge). The germanium concentration of the first semiconductor layer SEL 1  may range from 0 atomic percent (at %) to 10 at %. 
     The second semiconductor layer SEL 2  may have a relatively high germanium concentration. As an example, the germanium concentration of the second semiconductor layer SEL 2  may range from 30 at % to 70 at %. The germanium concentration of the second semiconductor layer SEL 2  may increase in the third direction D 3 . For example, the germanium concentration of the second semiconductor layer SEL 2  may be about 40 at % at a lower portion more proximate to the substrate  100  or near the first semiconductor layer SEL 1 , and may be about 60 at % at an upper portion or at its top level. 
     The first and second semiconductor layers SEL 1  and SEL 2  may include impurities (e.g., boron), allowing the first source/drain pattern SD 1  to have conductivity of a first type (e.g., p-type conductivity). In some embodiments, a concentration of impurities in the second semiconductor layer SEL 2  (as measured in at %) may be greater than that in the first semiconductor layer SEL 1 . 
     The first semiconductor layer SEL 1  may prevent a stacking fault from occurring between the substrate  100  and the second semiconductor layer SEL 2  and between the first to third semiconductor patterns SP 1 , SP 2 , and SP 3  and the second semiconductor layer SEL 2 . Such a stacking fault may lead to an increase of a channel resistance. The stacking fault may easily occur on the bottom of the first recess RS 1 . Thus, if the first semiconductor layer SEL 1  adjacent to the first recess RS 1  is provided to have a relatively large thickness, the stacking fault may be prevented. 
     Additionally or alternatively, the first semiconductor layer SEL 1  may protect the second semiconductor layer SEL 2 , in a process of replacing sacrificial layers SAL, which will be described in greater detail herein, with first to third portions P 01 , P 02 , and P 03  of a gate electrode GE. For example, the first semiconductor layer SEL 1  may prevent the second semiconductor layer SEL 2  from being undesirably etched by an etching material, which is used to remove the sacrificial layers SAL. 
     Gate electrodes GE may cross the first and second channel patterns CH 1  and CH 2  and may extend in the first direction D 1 . The gate electrodes GE may be arranged with a first pitch P 1  in the second direction D 2 . Each of the gate electrodes GE may be overlapped with or by the first and second channel patterns CH 1  and CH 2  when viewed in a plan view. 
     The gate electrode GE may include a first portion P 01  interposed between the first and second active patterns AP 1  and AP 2  and the first semiconductor pattern SP 1 , a second portion P 02  interposed between the first semiconductor pattern SP 1  and the second semiconductor pattern SP 2 , a third portion P 03  interposed between the second semiconductor pattern SP 2  and the third semiconductor pattern SP 3 , and a fourth portion P 04  on the third semiconductor pattern SP 3 . 
     Referring to  FIG. 2A , the first to third portions P 01 , P 02 , and P 03  of the gate electrode GE on the PMOSFET region PR may have different widths from each other. For example, the largest width of the third portion P 03  in the second direction D 2  may be larger than the largest width of the second portion P 02  in the second direction D 2 . The largest width of the first portion P 01  in the second direction D 2  may be larger than the largest width of the third portion P 03  in the second direction D 2 . 
     Referring to  FIG. 2D , the gate electrode GE may be provided on a top surface TS, a bottom surface BS, and opposite side surfaces SW of each of the first to third semiconductor patterns SP 1 , SP 2 , and SP 3 . In other words, the logic transistor according to some embodiments may be a three-dimensional field-effect transistor (e.g., multi-bridge channel field-effect transistor (MBCFET)), in which the gate electrode GE surrounds the channel pattern, e.g., three-dimensionally surrounds the channel pattern. 
     Referring to  FIGS. 1 and 2A to 2D , a pair of gate spacers GS may be respectively arranged on opposite side surfaces of the fourth portion P 04  of the gate electrode GE. The gate spacers GS may extend along the gate electrode GE and in the first direction D 1 . Top surfaces of the gate spacers GS may be higher than a top surface of the gate electrode GE. For example, the top surfaces of the gate spacers GS may be coplanar with a top surface of a first interlayer insulating layer  110 , which will be described in greater details herein. The gate spacers GS may be formed of or may include at least one of SiCN, SiCON, or SiN. In some embodiments, the gate spacers GS may have a multi-layered structure that includes at least two layers, each of which is made of SiCN, SiCON, or SiN. 
     A gate capping pattern GP may be provided on the gate electrode GE. The gate capping pattern GP may extend along the gate electrode GE and in the first direction D 1 . The gate capping pattern GP may be formed of or may include a material having an etch selectivity with respect to first and second interlayer insulating layers  110  and  120 , which will be described in greater details herein. For example, the gate capping patterns GP may be formed of or may include at least one of SiON, SiCN, SiCON, or SiN. 
     A gate insulating layer GI may be interposed between the gate electrode GE and the first channel pattern CH 1  and between the gate electrode GE and the second channel pattern CH 2 . As best seen in  FIG. 2D , the gate insulating layer GI may cover the top surface TS, the bottom surface BS, and the opposite side surfaces SW of each of the first to third semiconductor patterns SP 1 , SP 2 , and SP 3 . The gate insulating layer GI may cover the top surface of the device isolation layer ST below the gate electrode GE, as best seen in  FIG. 2D . 
     In some embodiments, the gate insulating layer GI may include a silicon oxide layer, a silicon oxynitride layer, and/or a high-k dielectric layer. The high-k dielectric layer may be formed of or may include at least one of high-k dielectric materials whose dielectric constants are higher than that of silicon oxide. As non-limiting examples, the high-k dielectric materials may be formed of or may include at least one of hafnium oxide, hafnium silicon oxide, hafnium zirconium oxide, hafnium tantalum oxide, lanthanum oxide, zirconium oxide, zirconium silicon oxide, tantalum oxide, titanium oxide, barium strontium titanium oxide, barium titanium oxide, strontium titanium oxide, lithium oxide, aluminum oxide, lead scandium tantalum oxide, and/or lead zinc niobate. 
     In some embodiments, the semiconductor device may include a negative capacitance (NC) FET using a negative capacitor. For example, the gate insulating layer GI may include a ferroelectric layer exhibiting a ferroelectric material property and a paraelectric layer exhibiting a paraelectric material property. 
     The ferroelectric layer may have a negative capacitance, and the paraelectric layer may have a positive capacitance. When two or more capacitors are connected in series and each capacitor has a positive capacitance, a total capacitance may be less than a capacitance of each of the capacitors. By contrast, when at least one of a series of serially-connected capacitors has a negative capacitance, a total capacitance of the serially-connected capacitors may have a positive value and may be greater than an absolute value of each capacitance. 
     When a ferroelectric layer having a negative capacitance and a paraelectric layer having a positive capacitance are connected in series, a total capacitance of the serially-connected ferroelectric and paraelectric layers may be increased. Due to such an increase of the total capacitance, a transistor including the ferroelectric layer may have a subthreshold swing (SS) less than 60 mV/decade, at room temperature. 
     The ferroelectric layer may have a ferroelectric material property. The ferroelectric layer may be formed of or may include at least one of, for example, hafnium oxide, hafnium zirconium oxide, barium strontium titanium oxide, barium titanium oxide, and/or lead zirconium titanium oxide. In some embodiments, the hafnium zirconium oxide may be hafnium oxide that is doped with zirconium (Zr). In some embodiments, the hafnium zirconium oxide may be a compound composed of hafnium (Hf), zirconium (Zr), and/or oxygen (O). 
     The ferroelectric layer may further include dopants. For example, the dopants may include at least one of aluminum (Al), titanium (Ti), niobium (Nb), lanthanum (La), yttrium (Y), magnesium (Mg), silicon (Si), calcium (Ca), cerium (Ce), dysprosium (Dy), erbium (Er), gadolinium (Gd), germanium (Ge), scandium (Sc), strontium (Sr), and/or tin (Sn). In some embodiments, the kind of the dopants in the ferroelectric layer may vary depending on a ferroelectric material included in the ferroelectric layer. 
     In some embodiments, the ferroelectric layer includes hafnium oxide, and the dopants in the ferroelectric layer may include at least one of, for example, gadolinium (Gd), silicon (Si), zirconium (Zr), aluminum (Al), and/or yttrium (Y). 
     In some embodiments, the dopants are aluminum (Al), and a content of aluminum in the ferroelectric layer may range from 3 to 8 at % (atomic percentage). In some embodiments, the content of the aluminum as the dopants may be a ratio of the number of aluminum atoms to the number of hafnium and aluminum atoms. 
     In some embodiments, the dopants are silicon (Si), and a content of silicon in the ferroelectric layer may range from 2 at % to 10 at %. In some embodiments, the dopants are yttrium (Y), and a content of yttrium in the ferroelectric layer may range from 2 at % to 10 at %. In some embodiments, the dopants are gadolinium (Gd), and a content of gadolinium in the ferroelectric layer may range from 1 at % to 7 at %. In some embodiments, the dopants are zirconium (Zr), and a content of zirconium in the ferroelectric layer may range from 50 at % to 80 at %. 
     The paraelectric layer may have a paraelectric material property. The paraelectric layer may be formed of or may include at least one of, for example, silicon oxide and/or high-k metal oxides. The metal oxides, which can be used as the paraelectric layer, may include at least one of, for example, hafnium oxide, zirconium oxide, and/or aluminum oxide, but the inventive concepts are not limited to these examples. 
     The ferroelectric layer and the paraelectric layer may be formed of or include the same material. The ferroelectric layer may have the ferroelectric material property, but the paraelectric layer may not have the ferroelectric material property. For example, in the case where the ferroelectric and paraelectric layers contain hafnium oxide, a crystal structure of the hafnium oxide in the ferroelectric layer may be different from a crystal structure of the hafnium oxide in the paraelectric layer. 
     The ferroelectric layer may exhibit the ferroelectric material property only when it is in a specific range of thickness. In some embodiments, the ferroelectric layer may have a thickness ranging from 0.5 to 10 nm, but the inventive concepts are not limited to this example. Since a critical thickness associated with the occurrence of the ferroelectric material property varies depending on the kind of the ferroelectric material, the thickness of the ferroelectric layer may be changed depending on the kind of the ferroelectric material. 
     As an example, the gate insulating layer GI may include a single ferroelectric layer. As another example, the gate insulating layer GI may include a plurality of ferroelectric layers spaced apart from each other. The gate insulating layer GI may have a multi-layered structure, in which a plurality of ferroelectric layers and a plurality of paraelectric layers are alternately stacked. 
     The gate electrode GE may include a first metal pattern and a second metal pattern on the first metal pattern. The first metal pattern may be provided on the gate insulating layer GI and may be adjacent to the first to third semiconductor patterns SP 1 , SP 2 , and SP 3 . The first metal pattern may include a work function metal, which can be used to adjust a threshold voltage of the transistor. By adjusting a thickness and composition of the first metal pattern, it may be possible to realize a transistor having a desired threshold voltage. For example, the first to third portions P 01 , P 02 , and P 03  of the gate electrode GE may be composed of or formed of the first metal pattern or the work function metal. 
     The first metal pattern may include a metal nitride layer. For example, the first metal pattern may include at least one metal, which may be selected from the group consisting of titanium (Ti), tantalum (Ta), aluminum (Al), tungsten (W) and molybdenum (Mo), and nitrogen (N), as examples. In some embodiments, the first metal pattern may further include carbon (C). The first metal pattern may include a plurality of work function metal layers, which are stacked. 
     The second metal pattern may include a metallic material whose resistance is lower than the first metal pattern. For example, the second metal pattern may include at least one metal selected from the group consisting of tungsten (W), aluminum (Al), titanium (Ti), and tantalum (Ta), as examples. For example, the fourth portion P 04  of the gate electrode GE may include the first metal pattern and the second metal pattern on the first metal pattern. 
     Referring to  FIG. 2B , inner spacers IP may be provided on the NMOSFET region NR. Each of the inner spacers IP may be interposed between the second source/drain pattern SD 2  and a corresponding one of the first to third portions P 01 , P 02 , and P 03  of the gate electrode GE. The inner spacers IP may be in direct contact with the second source/drain pattern SD 2 . Each of the first to third portions P 01 , P 02 , and P 03  of the gate electrode GE may be spaced apart from the second source/drain pattern SD 2  by the inner spacer IP. 
     The first interlayer insulating layer  110  may be provided on the substrate  100 . The first interlayer insulating layer  110  may cover the gate spacers GS and the first and second source/drain patterns SD 1  and SD 2 . The first interlayer insulating layer  110  may have a top surface that is substantially coplanar with the top surface of the gate capping pattern GP and the top surface of the gate spacer GS. A second interlayer insulating layer  120  may be formed on the first interlayer insulating layer  110  to cover the gate capping pattern GP. In some embodiments, at least one of the first and second interlayer insulating layers  110  and  120  may include a silicon oxide layer. 
     A pair of division structures DB, which may be opposite to each other in the second direction D 2 , may be provided at both sides of each of the first and second logic cells LC 1  and LC 2 . For example, the division structure DB may be provided on a boundary between the first and second logic cells LC 1  and LC 2 . The division structures DB may extend in the first direction D 1  and parallel to the gate electrodes GE. A pitch between the division structures DB and the gate electrode GE adjacent to each other may be equal to the first pitch P 1 . 
     The division structures DB may penetrate the first and second interlayer insulating layers  110  and  120  and may extend into the first and second active patterns AP 1  and AP 2 . The division structures DB may penetrate the first and second channel patterns CH 1  and CH 2 . The division structures DB may separate the PMOS and NMOSFET regions PR and NR of the first logic cell LC 1  from the PMOS and NMOSFET regions PR and NR of the second logic cell LC 2 . 
     Active contacts AC may penetrate the first and second interlayer insulating layers  110  and  120  and may be electrically connected to the first and second source/drain patterns SD 1  and SD 2 , respectively. A pair of the active contacts AC may be respectively provided at both sides of the gate electrode GE. When viewed in a plan view (e.g., as seen in  FIG. 1 ), the active contact AC may have a bar shape that is elongated in the first direction D 1 . 
     The active contact AC may be a self-aligned contact. For example, the active contact AC may be formed by a self-alignment process using the gate capping pattern GP and the gate spacer GS. In some embodiments, the active contact AC may cover at least a portion of a side surface of the gate spacer GS. Although not shown, the active contact AC may cover a portion of the top surface of the gate capping pattern GP. 
     Silicide patterns SC may be interposed respectively between the active contact AC and the first source/drain pattern SD 1  and between the active contact AC and the second source/drain pattern SD 2 . The active contact AC may be electrically connected to the source/drain pattern SD 1  or SD 2  through the silicide pattern SC. The silicide pattern SC may be formed of or may include at least one of metal silicide materials (e.g., titanium silicide, tantalum silicide, tungsten silicide, nickel silicide, and cobalt silicide). 
     A gate contact GC, which is electrically connected to the gate electrode GE, may penetrate the second interlayer insulating layer  120  and the gate capping pattern GP. Referring to  FIG. 2B , an upper region of each of the active contacts AC adjacent to the gate contact GC may be filled with an upper insulating pattern UIP. Accordingly, it may be possible to prevent a process failure (e.g., a short circuit), which may occur when the gate contact GC is in contact with the active contact AC adjacent thereto. 
     Each of the active contacts AC and gate contacts GC may include a conductive pattern FM and a barrier pattern BM enclosing the conductive pattern FM. For example, the conductive pattern FM may be formed of or may include at least one metal of aluminum, copper, tungsten, molybdenum, or cobalt. The barrier pattern BM may cover side and bottom surfaces of the conductive pattern FM. In some embodiments, the barrier pattern BM may include a metal layer and a metal nitride layer. The metal layer may be formed of or may include at least one of titanium, tantalum, tungsten, nickel, cobalt, or platinum. The metal nitride layer may include at least one of titanium nitride (TiN), tantalum nitride (TaN), tungsten nitride (WN), nickel nitride (NiN), cobalt nitride (CoN), or platinum nitride (PtN). 
     A first metal layer M 1  may be provided in a third interlayer insulating layer  130 . The first metal layer M 1  may include first and second power lines MPR 1  and MPR 2 , first to fifth lower interconnection lines MI 1  to MI 5 , and lower vias VI 1 . The lower vias VI 1  may be provided below the first and second power lines MPR 1  and MPR 2  and the first to fifth lower interconnection lines MI 1  to MI 5 . 
     The first and second power lines MPR 1  and MPR 2  may extend in the second direction D 2  and may be parallel to each other and cross the first and second logic cells LC 1  and LC 2 . A drain voltage VDD and a source voltage VSS may be applied to the first and second power lines MPR 1  and MPR 2 , respectively. 
     Referring to  FIG. 1 , a first cell boundary CB 1 , which may extend in the second direction D 2 , may be defined in each of the first and second logic cells LC 1  and LC 2 . A second cell boundary CB 2 , which may extend in the second direction D 2 , may be defined at an opposite side of the first and second logic cells LC 1  and LC 2  from the first cell boundary CB 1  in the first direction D 1 . The first power line MPR 1 , which as discussed above may be applied with the drain voltage VDD, may be arranged on the first cell boundary CB 1 . In other words, the first power line MPR 1  applied with the drain voltage VDD may extend along the first cell boundary CB 1  in the second direction D 2 . The second power line MPR 2 , which as discussed above may be applied with the source voltage VSS (e.g., a ground voltage), may be arranged on the second cell boundary CB 2 . In other words, the second power line MPR 2  applied with the source voltage VSS may extend along the second cell boundary CB 2  in the second direction D 2 . 
     The first to fifth lower interconnection lines MI 1  to MI 5  may be between the first and second power lines MPR 1  and MPR 2 . In detail, first to fifth interconnection tracks MTR 1 -MTR 5  may be defined between the first and second power lines MPR 1  and MPR 2 . The first to fifth interconnection tracks MTR 1 -MTR 5  may extend in the second direction D 2  to be parallel to each other. The first to fifth lower interconnection lines MI 1  to MI 5  may be arranged at a second pitch P 2  in the first direction D 1 . The second pitch P 2  may be smaller than the first pitch P 1 . 
     At least one first lower interconnection line MI 1  may be on the first interconnection track MTR 1 , at least one second lower interconnection line MI 2  may be on the second interconnection track MTR 2 , at least one third lower interconnection line MI 3  may be on the third interconnection track MTR 3 , at least one fourth lower interconnection line MI 4  may be on the fourth interconnection track MTR 4 , and at least one fifth lower interconnection line MI 5  may be on the fifth interconnection track MTR 5 . 
     The first to fifth lower interconnection lines MI 1  to MI 5  may extend along the first to fifth interconnection tracks MTR 1 -MTR 5 , respectively, in parallel to each other and in the second direction D 2 . When viewed in a plan view, each of the first to fifth lower interconnection lines MI 1  to MI 5  may have a line shape or a bar shape. 
     As best seen in  FIG. 2C , a linewidth of each of the first and second power lines MPR 1  and MPR 2  may be a first width W 1 . A linewidth of each of the first to fifth lower interconnection lines MI 1  to MI 5  may be a second width W 2 . The linewidths of the first and second power lines MPR 1  and MPR 2  and the first to fifth lower interconnection lines MI 1  to MI 5  may be in the first direction D 1 . The second width W 2  may be smaller than the first width W 1  (e.g., see  FIG. 2C ). For example, the second width W 2  may be smaller than 12 nm. The first width W 1  may be larger than 12 nm. 
     The lower vias VI 1  may be interposed between and electrically connect the first and second power lines MPR 1  and MPR 2  and the active contacts AC. The lower vias VI 1  may be interposed between and electrically connect the first to fifth lower interconnection lines MI 1  to MI 5  and the active and gate contacts AC and GC. 
     As non-limiting examples, the first and second power lines MPR 1  and MPR 2  and the first to fifth lower interconnection lines MI 1  to MI 5  may be formed of or may include at least one metallic material (e.g., copper (Cu), aluminum (Al), ruthenium (Ru), cobalt (Co), tungsten (W), and molybdenum (Mo)). 
     The interconnection lines MPR 1 , MPR 2 , and MI 1  to MI 5  of the first metal layer M 1  and the lower via VI 1  thereunder may be formed by separate processes, respectively. For example, the interconnection lines MPR 1 , MPR 2 , and MI 1  to MI 5  of the first metal layer M 1  may be formed by a single damascene process and the lower via VI 1  of the first metal layer M 1  may be formed by another single damascene process. The semiconductor device according to some embodiments may be fabricated using a sub-20 nm process. 
     A second metal layer M 2  may be provided in a fourth interlayer insulating layer  140 . The second metal layer M 2  may include upper interconnection lines M 2 _I. Each of the upper interconnection lines M 2 _I may be a line-shaped or bar-shaped pattern extending in the first direction D 1 . In other words, the upper interconnection lines M 2 _I may extend in the first direction D 1  to be parallel to each other. 
     The second metal layer M 2  may further include upper vias VI 2 . The upper vias VI 2  may be provided below the upper interconnection lines M 2 _I. The upper vias VI 2  may be interposed between and electrically connect the interconnection lines MPR 1 , MPR 2 , and MI 1  to MI 5  of the first metal layer M 1  and the upper interconnection lines M 2 _I, respectively. 
     The upper interconnection line M 2 _I of the second metal layer M 2  and the upper via VI 2  thereunder may be formed by the same process and may form a single pattern. For example, the upper interconnection line M 2 _I and the upper via VI 2  of the second metal layer M 2  may be formed by a dual damascene process. The upper interconnection lines M 2 _I may be formed of or may include at least one f metallic material (e.g., copper (Cu), aluminum (Al), ruthenium (Ru), cobalt (Co), tungsten (W), and molybdenum (Mo)). 
     In some embodiments, although not shown, additional metal layers (e.g., M 3 , M 4 , M 5 , and so forth) may be further stacked on the fourth interlayer insulating layer  140 . Each of the stacked metal layers may include routing lines. 
       FIG. 3  is a plan view illustrating the first to third lower interconnection lines, which are arranged on the first to third interconnection tracks of  FIG. 1 . Referring to  FIG. 3 , the first lower interconnection lines MI 1 , which are on the first interconnection track MTR 1 , may include a first interconnection line MI 1   a  and a second interconnection line MI 1   b.    
     The first interconnection line MI 1   a  may have a first end EN 1  provided at its tip, and the second interconnection line MI 1   b  may have a second end EN 2  provided at its tip. The first end EN 1  of the first interconnection line MI 1   a  and the second end EN 2  of the second interconnection line MI 1   b  may face each other in the second direction D 2 . 
     A distance between the first end EN 1  of the first interconnection line MI 1   a  and the second end EN 2  of the second interconnection line MI 1   b  may be a first distance TIT 1 . The first distance TIT 1  may be a distance between the tip of the first interconnection line MI 1   a  and the tip of the second interconnection line MI 1   b  (i.e., a tip-to-tip distance). The first distance TIT 1  may be relatively large. For example, the first distance TIT 1  may be larger than a second distance TIT 2 , which will be described below. 
     Each of the first end EN 1  of the first interconnection line MI 1   a  and the second end EN 2  of the second interconnection line MI 1   b  may have a curved or rounded shape. The curved or rounded shape may be convex. Each of the first end EN 1  of the first interconnection line MI 1   a  and the second end EN 2  of the second interconnection line MI 1   b  may have a relatively large curvature. For example, a first imaginary circle IMC 1  may be defined to be in contact with the second end EN 2  of the second interconnection line MI 1   b.  The second end EN 2  may include an arc corresponding to the first imaginary circle IMC 1 . Here, the first imaginary circle IMC 1  may be a circle that is fitted to the second end EN 2  of the curved shape. The first imaginary circle IMC 1 , and thus the second end EN 2 , may have a first radius R 1 . The first radius R 1  may be a curvature radius of the second end EN 2  of the second interconnection line MI 1   b.    
     In the present specification, the curvature will be defined as a reciprocal of a curvature radius. From this definition, the second end EN 2  of the second interconnection line MI 1   b  may have a relatively large curvature and/or may have a first curvature radius R 1  that is relatively small. 
     As an example, the first curvature radius R 1  of the second end EN 2  of the second interconnection line MI 1   b  may be smaller than a linewidth W 2  of the second interconnection line MI 1   b.  A ratio of the first curvature radius R 1  to the linewidth W 2  may range from 0.5 to 1. The first end EN 1  of the first interconnection line MI 1   a  may have substantially the same curvature and curvature radius as the second end EN 2  of the second interconnection line MI 1   b.  The first end EN 1  of the first interconnection line MI 1   a  and the second end EN 2  of the second interconnection line MI 1   b  may be curved or rounded toward each other across the first distance TIT 1 . 
     The third lower interconnection lines MI 3 , which are disposed on the third interconnection track MTR 3 , may include a third interconnection line MI 3   a  and a fourth interconnection line MI 3   b.  The third interconnection line MI 3   a  may have a third end EN 3  and a fourth end EN 4 , which are respectively provided at its opposite tips. The fourth interconnection line MI 3   b  may have a fifth end EN 5  provided at its tip. The fourth end EN 4  of the third interconnection line MI 3   a  and the fifth end EN 5  of the fourth interconnection line MI 3   b  may face each other in the second direction D 2 . 
     A distance between the fourth end EN 4  of the third interconnection line MI 3   a  and the fifth end EN 5  of the fourth interconnection line MI 3   b  may be a second distance TIT 2 . The second distance TIT 2  may be a distance between the tip of the third interconnection line MI 3   a  and the tip of the fourth interconnection line MI 3   b.  The second distance TIT 2  may be relatively small. The second distance TIT 2  may be smaller than the first distance TIT 1  of  FIG. 3 . 
     Each of the fourth end EN 4  of the third interconnection line MI 3   a  and the fifth end EN 5  of the fourth interconnection line MI 3   b  may have a curved or rounded shape. Each of the fourth end EN 4  of the third interconnection line MI 3   a  and the fifth end EN 5  of the fourth interconnection line MI 3   b  may have a relatively small curvature. For example, a second imaginary circle IMC 2  may be defined to be in contact with the fourth end EN 4  of the third interconnection line MI 3   a.  The fourth end EN 4  may include an arc corresponding to the second imaginary circle IMC 2 . The second imaginary circle IMC 2 , and thus the fourth end EN 4 , may have a second radius R 2 . The second radius R 2  may be a curvature radius of the fourth end EN 4  of the third interconnection line MI 3   a.  The fourth end EN 4  of the third interconnection line MI 3   a  may have a relatively small curvature and may have a second curvature radius R 2  that is relatively large. 
     The second curvature radius R 2  of the fourth end EN 4  of the third interconnection line MI 3   a  may be larger than the linewidth W 2  of the third interconnection line MI 3   a.  A ratio of the second curvature radius R 2  to the linewidth W 2  may range from 1 to 10. The second curvature radius R 2  of the fourth end EN 4  of the third interconnection line MI 3   a  may be greater than the first curvature radius R 1  of the second end EN 2  of the second interconnection line MI 1   b.  In other words, a curvature of the fourth end EN 4  of the third interconnection line MI 3   a  may be smaller than a curvature of the second end EN 2  of the second interconnection line MI 1   b.  The fifth end EN 5  of the fourth interconnection line MI 3   b  may have substantially the same curvature and curvature radius as the fourth end EN 4  of the third interconnection line MI 3   a.  The fourth end EN 4  of the third interconnection line MI 3   a  and the fifth end EN 5  of the fourth interconnection line MI 3   b  may be curved or rounded toward each other across the first distance TIT 2 . 
     The third end EN 3  of the third interconnection line MI 3   a,  which is opposite to the fourth end EN 4 , may have the first curvature radius R 1  smaller than the second curvature radius R 2 . A curvature of the third end EN 3  of the third interconnection line MI 3   a  may be larger than the curvature of the fourth end EN 4 . In some embodiments, opposite ends of at least one of the interconnection lines may have different curvatures from each other. 
     In some embodiments, the curvature of the tip of the interconnection line may vary depending on a tip-to-tip distance between the interconnection lines on each interconnection track. For example, in the case where a distance between the interconnection lines is relatively large (e.g., the distance TIT 1  between the first and second interconnection lines MI 1   a  and MI 1   b ), the corresponding tips EN 1  and EN 2  may have a relatively large curvature. By contrast, in the case where a distance between the interconnection lines is relatively small (e.g., the distance TIT 2  between the third and fourth interconnection lines MI 3   a  and MI 3   b ), the corresponding tips EN 4  and EN 5  may have a relatively small curvature. 
     The first to fourth interconnection lines MI 1   a,  MI 1   b,  MI 3   a,  and MI 3   b  described above may have the same linewidth (i.e., the linewidth W 2 ). Each of the first to fourth interconnection lines MI 1   a,  MI 1   b,  MI 3   a,  and MI 3   b  may extend in the second direction D 2  while the linewidth thereof in the first direction D 1  is maintained at a constant value or at a substantially constant value (i.e., the linewidth W 2 ). The linewidth W 2  of each of the first to fourth interconnection lines MI 1   a,  MI 1   b,  MI 3   a,  and MI 3   b  may decrease at the ends EN 1  to EN 5  thereof based on the curvature of the ends EN 1  to EN 5 , and the linewidth may not increase at the ends EN 1  to EN 5 . 
     The second lower interconnection line MI 2  may be provided on the second interconnection track MTR 2 , which may be located between the first and third interconnection tracks MTR 1  and MTR 3 . For example, the second lower interconnection line MI 2  may be interposed between the first lower interconnection line MI 1  and the third lower interconnection line MI 3 . 
     The linewidth W 2  of the second lower interconnection line MI 2  may be substantially equal to the linewidth W 2  of each of the first to fourth interconnection lines MI 1   a,  MI 1   b,  MI 3   a,  and MI 3   b.  A pitch P 2  between the first and second lower interconnection lines MI 1  and MI 2  may be substantially equal to a pitch P 2  between the third and second lower interconnection lines MI 3  and MI 2 . The pitch P 2  between the first and second lower interconnection lines MI 1  and MI 2  and the third and second lower interconnection lines MI 3  and MI 2  may be measured from a center or central portion of the interconnection lines MI 1  to MI 3 , e.g., the first to third interconnection tracks MTR 1  to MTR 3 . A distance SPD 1  between the first and second lower interconnection lines MI 1  and MI 2  may be substantially equal to the distance SPD 1  between the third and second lower interconnection lines MI 3  and MI 2 . 
     The second lower interconnection line MI 2  may extend in the second direction D 2  while the linewidth thereof is maintained in the first direction D 1  at a constant value or at a substantially constant value (i.e., the linewidth W 2 ). In other words, the linewidth in the first direction D 1  of the second lower interconnection line MI 2  may be uniform along the second direction D 2  for the extent of the second lower interconnection line MI 2 . In greater detail, the second lower interconnection line MI 2  may include a first portion PT 1  and a second portion PT 2 . The first portion PT 1  may be a portion of the second lower interconnection line MI 2  that is located near a region between the first end EN 1  of the first interconnection line MI 1   a  and the second end EN 2  of the second interconnection line MI 1   b,  or near the first distance TIT 1 . The second portion PT 2  may be another portion of the second lower interconnection line MI 2  that is located near a region between the fourth end EN 4  of the third interconnection line MI 3   a  and the fifth end EN 5  of the fourth interconnection line MI 3   b,  or near the second distance TIT 2 . 
     The first portion PT 1  may extend in the second direction D 2  while the linewidth thereof is maintained at a constant value or at a substantially constant value (i.e., the linewidth W 2 ), even when the first lower interconnection line MI 1  is absent in a region of the first interconnection track MTR 1  adjacent to the first portion PT 1 . In other words, even at the first portion PT 1  across from the first distance TIT 1 , the uniform linewidth of the second lower interconnection line MI 2  may be maintained. 
     The second portion PT 2  may extend in the second direction D 2  while the linewidth thereof is maintained at a constant value or at a substantially constant value (i.e., the linewidth W 2 ), even when the third lower interconnection line MI 3  is absent in a region of the third interconnection track MTR 3  adjacent to the second portion PT 2 . In other words, even at the first portion PT 2  across from the second distance TIT 2 , the uniform linewidth of the second lower interconnection line MI 2  may be maintained. 
       FIG. 4  is a plan view illustrating a structure according to a comparative example of  FIG. 3 . Referring to  FIG. 4 , the first portion PT 1  of the second lower interconnection line MI 2  may protrude toward the first interconnection track MTR 1 . Accordingly, a width W 3  of the first portion PT 1  of the second lower interconnection line MI 2  may be larger or greater than the linewidth W 2  of the second lower interconnection line MI 2 . The second portion PT 2  of the second lower interconnection line MI 2  may protrude toward the third interconnection track MTR 3 . Thus, a width W 3  of the second portion PT 2  of the second lower interconnection line MI 2  may be larger than the linewidth W 2  of the second lower interconnection line MI 2 . 
     In the comparative example of  FIG. 4 , when lower interconnection lines are formed using a multi-patterning technology (MPT), the second lower interconnection line MI 2  may be formed to include portions (e.g., the first and second portions PT 1  and PT 2 ) having an abruptly increased linewidth. For example, the first portion PT 1  of the second lower interconnection line MI 2  may have a shape that extends into an empty region between the first and second interconnection lines MI 1   a  and MI 1   b.  The second portion PT 2  of the second lower interconnection line MI 2  may have a shape that extends into an empty region between the third and fourth interconnection lines MI 3   a  and MI 3   b.    
     Thus, as shown in  FIG. 4 , the second lower interconnection line MI 2  that includes the first and second portions PT 1  and PT 2  having an increased linewidth may occupy a greater volume or area than is necessary or desired. For example, from a comparison of the second lower interconnection lines MI 2  of  FIGS. 3 and 4 , it can be seen that a volume (or area) of the second lower interconnection line MI 2  of  FIG. 3  according to some embodiments is smaller than a volume (or area) of the second lower interconnection line MI 2  of  FIG. 4  of the comparative example. If a size of the second lower interconnection line MI 2  is unnecessarily increased by a fabrication process, such as that of  FIG. 4 , a parasitic capacitance in the first metal layer M 1  may be increased, and this may lead to deterioration in electric characteristics of the semiconductor device. 
     By contrast, in the embodiment of  FIG. 3  (i.e., according to some embodiments of the inventive concepts), the first and second portions PT 1  and PT 2  of the second lower interconnection line MI 2  may not be extended into the distances TIT 1  and TIT 2  and may have a constant linewidth W 2  or substantially constant linewidth W 2  that is maintained in the first direction D 1 . Accordingly, it may be possible to maximally reduce a volume or area that is occupied by a metal pattern (i.e., an interconnection line) in the first metal layer M 1 , and thereby to reduce parasitic capacitance in the first metal layer M 1 . As a result, the semiconductor device may have improved electric characteristics. 
       FIGS. 5, 7, 9, 11, 13, 15, 17, and 19  are plan views illustrating a method of fabricating a first metal layer, according to some embodiments of the inventive concepts.  FIGS. 6, 8A, 10A, 12A, 14A, 16A, 18A, and 20A  are sectional views taken along lines I-I′ of  FIGS. 5 ,  7 ,  9 ,  11 ,  13 ,  15 ,  17 , and  19 , respectively.  FIGS. 8B, 10B, 12B, 14B, 16B, 18B, and 20B  are sectional views taken along lines II-II′ of  FIGS. 7, 9, 11, 13, 15, 17, and 19 , respectively. 
     Referring to  FIGS. 5 and 6 , the logic transistors previously described with reference to  FIGS. 1 and 2A to 2D  may be formed on the substrate  100 . The third interlayer insulating layer  130  may be formed on the logic transistors. An etch target layer ETL may be formed on the third interlayer insulating layer  130 . The etch target layer ETL may include a barrier layer BML and a metal layer CIVIL, which may be sequentially stacked. The barrier layer BML may be formed of or include at least one of tantalum nitride (TaN), titanium nitride (TiN), tantalum oxide (TaO), titanium oxide (TiO), manganese nitride (MnN), or manganese oxide (MnO). The metal layer CIVIL may be formed of or may include at least one metallic material (e.g., copper (Cu), aluminum (Al), ruthenium (Ru), cobalt (Co), tungsten (W), and molybdenum (Mo)). A first mold layer MO 1  and a second mold layer MO 2  may be sequentially formed on the etch target layer ETL. 
     First line patterns MAP 1  may be formed on the second mold layer MO 2 . The first line patterns MAP 1  may extend in the second direction D 2  and may be parallel to each other. Each of the first line patterns MAP 1  may serve as a mandrel in a multi-patterning technology according to some embodiments. 
     In detail, the first and fourth ones of the first line patterns MAP 1  may be formed at positions corresponding to the first and second power lines MPR 1  and MPR 2  previously described with reference to  FIG. 1 . The second and third ones of the first line patterns MAP 1  may be formed on the second and fourth interconnection tracks MTR 2  and MTR 4 , respectively. The first to fourth ones of the first line patterns MAP 1  may have different widths in the first direction D 1 . 
     Referring to  FIGS. 7, 8A, and 8B , the first line patterns MAP 1  may be removed from a first cutting region CTP 1  by an etching process. For example, although not shown, a mask pattern defining the first cutting region CTP 1  may be formed by a photolithography process, and then, the first line patterns MAP 1  may be etched using the mask pattern as an etch mask. 
     The first line pattern MAP 1  on the second interconnection track MTR 2  may be divided into a pair of the first line patterns MAP 1  by the first cutting region CTP 1 . The first line pattern MAP 1  on the fourth interconnection track MTR 4  may be divided into a pair of the first line patterns MAP 1  by the first cutting region CTP 1 . 
     Referring to  FIGS. 9, 10A, and 10B , spacers SPS may be formed on the first line patterns MAP 1 . The spacer SPS may be formed on a side surface of each of the first line patterns MAP 1 . When viewed in a plan view, each of the spacers SPS may be a line-shaped pattern that extends along the first line pattern MAP 1  in the second direction D 2 . 
     In greater detail, the formation of the spacers SPS may include forming a spacer layer on the first line patterns MAP 1  and anisotropically etching the spacer layer to expose top surfaces of the first line patterns MAP 1  or a top surface of the second mold layer MO 2 . 
     The spacers SPS may be connected to each other in the first cutting region CTP 1  and in some embodiments may fill the area between the pairs of the first line patterns MAP 1  in the first cutting region CTP 1 . For example, the spacer SPS may include a connecting portion SPR filling the first cutting region CTP 1 . 
     Referring to  FIGS. 11, 12A, and 12B , second line patterns MAP 2  may be formed on the second mold layer MO 2  to fill empty spaces between the spacers SPS, respectively. The second line patterns MAP 2  may extend in the second direction D 2  and may be parallel to each other. The first one of the second line patterns MAP 2 , the second one of the second line patterns MAP 2 , and the third one of the second line patterns MAP 2  may be formed on the first interconnection track MTR 1 , the third interconnection track MTR 3 , and the fifth interconnection track MTR 5 , respectively. 
     In greater detail, the formation of the second line patterns MAP 2  may include forming an insulating layer on the second mold layer MO 2  and recessing the insulating layer to expose upper portions of the spacers SPS (e.g., in an etch-back manner). 
     According to some embodiments, the first line patterns MAP 1  may be formed to have a line shape, without any substantial change of or substantial deviation along the second direction D 2  in the linewidth thereof in the first direction D 1 . By using the first line patterns MAP 1  as a mandrel, the second line patterns MAP 2  may be formed in a line shape, without any substantial change or substantial deviation along the second direction D 2  in the linewidth of the second line patterns MAP 2  in the first direction D 1 . 
     Referring to  FIGS. 13, 14A, and 14B , hard mask patterns HMP may be formed on the second line patterns MAP 2 . The hard mask patterns HMP may be formed through a first photolithography process. The second line patterns MAP 2  may be selectively etched using the hard mask patterns HMP as an etch mask. The etching process may be performed using an anisotropic etching process. The second line patterns MAP 2  below the hard mask patterns HMP may not be removed during the etching process, because they are protected by the hard mask patterns HMP. 
     In greater detail, a first line LIN 1  and a second line LIN 2  may be formed from the first one of the second line patterns MAP 2  (i.e., the second line pattern MAP 2  on the first interconnection track MTR 1 ) through the first photolithography process. The first line LIN 1  and the second line LIN 2  may correspond to the first and second interconnection lines MI 1   a  and MI 1   b,  respectively, described with reference to  FIG. 3 . In other words, the first line LIN 1  and the second line LIN 2  may be spaced apart from each other in the second direction D 2  by the first distance TIT 1 . The first line LIN 1  and the second line LIN 2 , which are spaced apart from each other by a relatively large distance, may be formed through the hard mask patterns HMP. 
     Due to the planar shape of the hard mask pattern HMP, a first end of the first line LIN 1  and a second end of the second line LIN 2  may be formed to have a relatively large curvature. This may be substantially the same as the first end EN 1  of the first interconnection line MI 1   a  and the second end EN 2  of the second interconnection line MI 1   b,  previously described with reference to  FIG. 3 . 
     Referring to  FIGS. 15, 16A, and 16B , the second line pattern MAP 2  may be removed from a second cutting region CTP 2  by an etching process. For example, although not shown, a mask pattern defining the second cutting region CTP 2  may be formed by a second photolithography process, and then, the second line pattern MAP 2  may be etched using the mask pattern as an etch mask. 
     In greater detail, a third line LIN 3  and a fourth line LIN 4  may be formed from the second one of the second line patterns MAP 2  (i.e., the second line pattern MAP 2  on the third interconnection track MTR 3 ) through the second photolithography process. The third line LIN 3  and the fourth line LIN 4  may correspond to the third and fourth interconnection lines MI 3   a  and MI 3   b,  respectively, described with reference to  FIG. 3 . In other words, the third line LIN 3  and the fourth line LIN 4  may be spaced apart from each other in the second direction D 2  by the second distance TIT 2 . The third line LIN 3  and the fourth line LIN 4 , which are spaced apart from each other by a relatively small distance, may be formed through the second cutting region CTP 2 . 
     Due to the planar shape of the second cutting region CTP 2 , a third end of the third line LIN 3  and a fourth end of the fourth line LIN 4  may be formed to have a relatively small curvature. This may be substantially the same as the fourth end EN 4  of the third interconnection line MI 3   a  and the fifth end EN 5  of the fourth interconnection line MI 3   b,  previously described with reference to  FIG. 3 . 
     Referring to  FIGS. 17, 18A, and 18B , the spacers SPS may be selectively removed. Accordingly, only the first and second line patterns MAP 1  and MAP 2  may be left on the second mold layer MO 2 . 
     Referring to  FIGS. 19, 20A, and 20B , the first and second mold layers MO 1  and MO 2  may be patterned using the first and second line patterns MAP 1  and MAP 2  as an etch mask. Next, the etch target layer ETL may be patterned using the patterned first and second mold layers MO 1  and MO 2  as an etch mask. Accordingly, the interconnection lines MPR 1 , MPR 2 , and MI 1  to MI 5  of the first metal layer M 1  may be formed on the third interlayer insulating layer  130 . 
     Each of the interconnection lines MPR 1 , MPR 2 , and MI 1  to MI 5  may include a barrier pattern BMP and a metal pattern CMP. The barrier pattern BMP may cover a bottom surface of the metal pattern CMP. In some embodiments, the interconnection lines MPR 1 , MPR 2 , and MI 1  to MI 5  may be formed by a subtractive process of etching the etch target layer ETL. 
       FIGS. 21, 23, 25, 27, 29, and 31  are plan views illustrating a method of fabricating a first metal layer, according to some embodiments of the inventive concepts.  FIGS. 22A, 24A, 26A, 28A, 30A, and 32A  are sectional views taken along lines I-I′ of  FIGS. 21, 23, 25, 27, 29, and 31 , respectively.  FIGS. 22B, 24B, 26B, 28B, 30B, and 32B  are sectional views taken along lines II-II′ of  FIGS. 21, 23, 25, 27, 29, and 31 , respectively. For concise description, elements previously described with reference to  FIGS. 5 to 20B  may be identified by previously-used reference numbers, and an overlapping description thereof may be omitted. 
     The etch target layer ETL according to some embodiments may be the third interlayer insulating layer  130 . In other words, the barrier layer BML and the metal layer CIVIL may be omitted, unlike the afore-described embodiment. In the fabrication method according to some embodiments, the interconnection lines may be formed by a damascene process of filling a concave region of an interlayer insulating layer with a metal layer, not by a subtractive process of etching the metal layer. 
     Referring to  FIGS. 21, 22A, and 22B , a filling pattern FIP may be formed on the resulting structure of  FIGS. 9, 10A, and 10B . The filling pattern FIP may be formed in the second cutting region CTP 2 . The filling pattern FIP may be formed in a space between adjacent ones of the spacers SPS, in the second cutting region CTP 2 . 
     Referring to  FIGS. 23, 24A, and 24B , the second line patterns MAP 2  may be formed on the second mold layer MO 2  to fill empty spaces between the spacers SPS, respectively. The second line patterns MAP 2  may extend in the second direction D 2  and may be parallel to each other. The second line pattern MAP 2  on the third interconnection track MTR 3  may be divided into a pair of the second line patterns MAP 2  by the filling pattern FIP. 
     Referring to  FIGS. 25, 26A, and 26B , the hard mask pattern HMP may be formed on the first and second line patterns MAP 1  and MAP 2 . The hard mask pattern HMP may include a plurality of first openings OPN 1 . Each of the first openings OPN 1  may be formed to overlap at least a portion of the second line pattern MAP 2 . For example, at least a portion of the second line pattern MAP 2  may be exposed through the first opening OPN 1 . In some embodiments, the filling pattern FIP may also be exposed through the first opening OPN 1 . 
     Referring to  FIGS. 27, 28A, and 28B , the portions of the second line patterns MAP 2 , which are exposed through the first openings OPN 1 , may be selectively removed using the hard mask pattern HMP as an etch mask. Since the filling pattern FIP has an etch selectivity with respect to the second line pattern MAP 2 , the filling pattern FIP may not be removed during the removal of the second line patterns MAP 2  and may be left as it is. 
     Empty regions, which are formed by removing the second line patterns MAP 2 , may be defined as second openings OPN 2 , respectively. Each of the second openings OPN 2  may expose the top surface of the second mold layer MO 2 , between the spacers SPS. 
     Referring to  FIGS. 29, 30A, and 30B , the first line patterns MAP 1  may be selectively removed. For example, empty regions, which are formed by removing the first line patterns MAP 1 , may be defined as third openings OPN 3 , respectively. Each of the third openings OPN 3  may expose the top surface of the second mold layer MO 2 , between the spacers SPS. 
     Since the first line patterns MAP 1  are selectively removed, the spacers SPS, portions of the second line patterns MAP 2 , and the filling pattern FIP may be left on the second mold layer MO 2 . 
     Referring to  FIGS. 31, 32A, and 32B , the first and second mold layers MO 1  and MO 2  may be patterned using the spacers SPS, the second line patterns MAP 2 , and the filling pattern FIP, which are left on the second mold layer MO 2 , as an etch mask. Next, an upper portion of the etch target layer ETL (i.e., the third interlayer insulating layer  130 ) may be recessed using the patterned first and second mold layers MO 1  and MO 2  as an etch mask. As a result, the second and third openings OPN 2  and OPN 3  defined above may be extended into the upper portion of the third interlayer insulating layer  130 . 
     Thereafter, the second and third openings OPN 2  and OPN 3  may be filled with a metallic material. Accordingly, the interconnection lines of the first metal layer M 1  may be formed in the upper portion of the third interlayer insulating layer  130 . 
       FIGS. 33 and 34  are plan views, each of which illustrates first to third lower interconnection lines of  FIG. 1 , according to some embodiments of the inventive concepts. For concise description, elements previously described with reference to  FIGS. 1 to 3  may be identified by previously-used reference numbers, and an overlapping description thereof may be omitted. 
     Referring to  FIG. 33 , the fourth end EN 4  of the third interconnection line MI 3   a  may have a curvature opposite to a curvature of the third end EN 3 . In greater detail, the second imaginary circle IMC 2  corresponding to the fourth end EN 4  of the third interconnection line MI 3   a  may be defined outside the third interconnection line MI 3   a.  The center of the second imaginary circle IMC 2  corresponding to the fourth end EN 4  of the third interconnection line MI 3   a  may be outside the third interconnection line MI 3   a.  By contrast, the first imaginary circle IMC 1  corresponding to the third end EN 3  of the third interconnection line MI 3   a  may be defined within the third interconnection line MI 3   a.  The center of the first imaginary circle IMC 1  corresponding to the third end EN 3  of the third interconnection line MI 3   a  may be within the third interconnection line MI 3   a.  The fifth end EN 5  of the fourth interconnection line MI 3   b  may also have substantially the same curvature as the fourth end EN 4 . In other words, an imaginary circle corresponding to the fifth end EN 5  of the fourth interconnection line MI 3   b  may also be defined outside the fourth interconnection line MI 3   b.  Stated differently, the fourth end EN 4  of the third interconnection line MI 3   a  and the fifth end EN 5  of the fourth interconnection line MI 3   b  may be curved away or concave from each other across the distance (e.g., TIT 2 ) therebetween. 
     Referring to  FIG. 34 , the first to fourth interconnection lines MI 1   a,  MI 1   b,  MI 3   a,  and MI 3   b  on the first and third interconnection tracks MTR 1  and MTR 3  may have the same linewidth (i.e., the second width W 2 ). By contrast, the second lower interconnection line MI 2  on the second interconnection track MTR 2  may have a linewidth W 3  that is different from the second width W 2 . In some embodiments, the linewidth W 3  of the second interconnection track MTR 2  may be larger than the second width W 2 . In some embodiments, the linewidth W 3  of the second interconnection track MTR 2  may be smaller than the second width W 2 . 
     Even when the linewidth W 3  of the second lower interconnection line MI 2  is different from the linewidth W 2  of each of the first and third lower interconnection lines MI 1  and MI 3 , the distance SPD 1  between the first and second lower interconnection lines MI 1  and MI 2  may be equal to the distance SPD 1  between the third and second lower interconnection lines MI 3  and MI 2 . This is because the pitch P 2  between the first and second lower interconnection lines MI 1  and MI 2  is still the same as the pitch P 2  between the third and second lower interconnection lines MI 3  and MI 2 . 
     According to the afore-described fabrication method, the second lower interconnection line MI 2  on the second interconnection track MTR 2  may have a linewidth that is determined by a linewidth of the first line pattern MAP 1 , and the first and third lower interconnection lines MI 1  and MI 3  on the first and third interconnection tracks MTR 1  and MTR 3  may have a linewidth that is determined by a linewidth of the second line patterns MAP 2 . Thus, in the case where the first and second line patterns MAP 1  and MAP 2  are formed to have different linewidths from each other, the linewidths of the lower interconnection lines may be different from each other, as shown in  FIG. 34 . 
     Although not fully shown in  FIG. 34 , referring back to  FIG. 1 , since the first, third and fifth lower interconnection lines MI 1 , MI 3 , and MI 5  on the first, third and fifth interconnection tracks MTR 1 , MTR 3 , and MTR 5  are formed by the second line patterns MAP 2 , they may have the same linewidth or substantially the same linewidth (e.g., the second width W 2 ). Since the second and fourth lower interconnection lines MI 2  and MI 4  on the second and fourth interconnection tracks MTR 2  and MTR 4  are formed by the first line patterns MAP 1 , they may have the same linewidth or substantially the same linewidth (e.g., a third width W 3 ). In some embodiments, the second width W 2  may be different from the third width W 3 . 
       FIGS. 35A to 35D  are sectional views, which are respectively taken along lines A-A′, B-B′, C-C′, and D-D′ of  FIG. 1  to illustrate a semiconductor device according to some embodiments of the inventive concepts. For concise description, elements previously described with reference to  FIGS. 1 and 2A to 2D  may be identified by previously-used reference numbers, and an overlapping description thereof may be omitted. 
     The PMOSFET and NMOSFET regions PR and NR may be defined by a second trench TR 2 , which is formed in an upper portion of the substrate  100 . The second trench TR 2  may be located between the PMOSFET and NMOSFET regions PR and NR. The PMOSFET and NMOSFET regions PR and NR may be spaced apart from each other in the first direction D 1  with the second trench TR 2  interposed therebetween. 
     The first active patterns AP 1  and the second active patterns AP 2  may be provided on the PMOSFET region PR and the NMOSFET region NR, respectively. The first and second active patterns AP 1  and AP 2  may extend in the second direction D 2  and may be parallel to each other. The first and second active patterns AP 1  and AP 2  may be portions of the substrate  100  protruding in a vertical direction (i.e., the third direction D 3 ). First trenches TR 1  may be defined between adjacent ones of the first active patterns AP 1  and between adjacent ones of the second active patterns AP 2 . The first trench TR 1  may be shallower than the second trench TR 2 . 
     The device isolation layer ST may fill the first and second trenches TR 1  and TR 2 . Upper portions of the first and second active patterns AP 1  and AP 2  may protrude vertically above the device isolation layer ST (e.g., see  FIG. 35D ). Each of the upper portions of the first and second active patterns AP 1  and AP 2  may have a fin shape. The device isolation layer ST may not cover the upper portions of the first and second active patterns AP 1  and AP 2 . The device isolation layer ST may cover lower side surfaces of the first and second active patterns AP 1  and AP 2 . 
     The first source/drain patterns SD 1  may be provided on the first active patterns AP 1 . The first source/drain patterns SD 1  may be impurity regions of a first conductivity type (e.g., p-type). The first channel pattern CH 1  may be interposed between each pair of the first source/drain patterns SD 1 . The second source/drain patterns SD 2  may be provided on the second active patterns AP 2 . The second source/drain patterns SD 2  may be impurity regions of a second conductivity type (e.g., n-type). The second channel pattern CH 2  may be interposed between each pair of the second source/drain patterns SD 2 . Other features associated with the first and second source/drain patterns SD 1  and SD 2  may be the same as or similar to those in the example embodiments described with reference to  FIGS. 1 and 2A to 2D . 
     The gate electrodes GE may cross the first and second active patterns AP 1  and AP 2  and to extend in the first direction D 1 . The gate electrodes GE may be vertically overlapped with the first and second channel patterns CH 1  and CH 2 . Each of the gate electrodes GE may surround top and opposite side surfaces of each of the first and second channel patterns CH 1  and CH 2 . Referring to  FIG. 35D , the gate electrode GE may be provided on a first top surface TS 1  of the first channel pattern CH 1  and at least one first side surface SW 1  of the first channel pattern CH 1 . The gate electrode GE may be provided on a second top surface TS 2  of the second channel pattern CH 2  and at least one second side surface SW 2  of the second channel pattern CH 2 . In other words, the transistor according to some embodiments may be a three-dimensional field-effect transistor (e.g., FinFET), in which the gate electrode GE three-dimensionally surrounds the channel patterns CH 1  and CH 2 . 
     Features associated with the active and gate contacts AC and GC and the first and second metal layers M 1  and M 2  may be the same as or similar to those in the example embodiments described with reference to  FIGS. 1 and 2A to 2D . 
     In a semiconductor device according to some embodiments of the inventive concepts, since interconnection lines of a first metal layer may be formed by a multi-patterning technology, the interconnection lines may be formed to have a small linewidth and a small pitch. Accordingly, an integration density of the semiconductor device may be increased. In addition, it may be possible to prevent unnecessary metal portions (e.g., dummy portions) from being formed in the first metal layer and to minimize a volume or area of the interconnection lines in the first metal layer, even when the multi-patterning technology is used to fabricate the semiconductor device. As a result, it may be possible to reduce parasitic capacitance in the first metal layer and to improve electric characteristics of the device. 
     While example embodiments of the inventive concepts have been particularly shown and described, it will be understood by one of ordinary skill in the art that variations in form and detail may be made therein without departing from the scope of the attached claims.