Patent Publication Number: US-2021165947-A1

Title: Integrated circuits including standard cell structures and layout methods

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of priority under 35 U.S.C. § 119 to Korean Patent Application No. 10-2019-0156559 filed on Nov. 29, 2019, and to Korean Patent Application No. 10-2020-0073127 filed on Jun. 16, 2020, both filed in the Korean Intellectual Property Office, the contents of each of which are herein incorporated by reference in their entireties. 
     BACKGROUND 
     1. Technical Field 
     The present disclosure relates to layout methods of integrated circuits including integrated standard cell structures. 
     2. Description of the Related Art 
     Integrated circuits may be designed on the basis of standard cells. Specifically, layouts of integrated circuits may be generated by placing standard cells according to data defining the integrated circuits and by routing the placed standard cells. Standard cells may be predesigned and stored in a cell library. 
     With the miniaturization of semiconductor fabricating processes, sizes of patterns in each of the standard cells may decrease, and size of the standard cells themselves may also decrease. 
     SUMMARY 
     Some aspects of the present disclosure may provide layout methods of integrated circuits having layouts which may be used in miniaturized semiconductor fabrication processes due to patterns of simple or more simplified structures. 
     Some aspects of the present disclosure may also provide layout methods of integrated circuits having improved operational reliability due to the layout of the simplified structures. 
     Some aspects of the present disclosure may provide, as an example, a layout method of an integrated circuit including standard cells, the layout method comprising placing first and second standard cells selected from a standard cell library, interconnecting the placed first and second standard cells to generate a layout draft, confirming placement and routing at a boundary region between the interconnected first and second standard cells and revising the layout draft as a result of the confirmation. Each of the standard cells may include an active region that extends in a first direction, a gate line that extends in a second direction and that intersects the active region, a source/drain region that extends in the second direction and is placed on one side of the gate line, a source/drain via placed on the source/drain region and a conductive line that extends in the first direction and is interconnected to an adjacent standard cell through the source/drain via. Confirming the placement and routing may include comparing a first spaced distance from a tip of a first conductive line of the first standard cell to a tip of a second conductive line of the second standard cell, and a second spaced distance from the tip of the first conductive line of the first standard cell to the cell boundary with first and second preset threshold values, respectively, and revising the layout draft may include adjusting, a tip position of the conductive line of the second standard cell. 
     Some aspects of the present disclosure may provide, as an example, a layout method of an integrated circuit, the layout method comprising steps of placing a first standard cell and a second standard cell from a standard cell library on respective sides of a cell boundary, placing a source/drain via and a conductive line on each of the first standard cell and the second standard cell, measuring a first spaced distance between a tip of the conductive line of the first standard cell and measuring a second spaced distance between a tip of the conductive line of the second standard cell and the cell boundary, adjusting a tip position of the tip of the conductive line of the first standard cell or a tip position of the tip of the conductive line of the second standard cell when the first spaced distance or the second spaced distance is equal to or greater than a preset threshold value and settling a layout at the of the conductive line having the adjusted tip position. 
     Some aspects of the present disclosure may provide, as an example, an integrated circuit that includes a first standard cell and a second standard cell adjacent to each other in a first direction. The first standard cell comprises, a first gate line that extends in a second direction, a first source/drain region that extends in the second direction and is placed on one side of the first gate line, a first source/drain via that is placed on the first source/drain region and a first conductive line that extends in the first direction and is placed to be connected to an upper surface of the first source/drain via, The second standard cell comprises, a second gate line that extends in the second direction, a second source/drain region that extends in the second direction and is placed between the second gate line and a cell boundary with the first standard cell, a second source/drain via that is placed on the second source/drain region and a second conductive line that extends in the first direction and is placed to be connected to an upper surface of the second source/drain via. When a spaced distance between a tip of the first conductive line facing the cell boundary and a tip of the second conductive line facing the cell boundary is equal to or greater than a preset threshold value, a length in the first direction from the tip of the first conductive line to an intersection of the first conductive line with the first source/drain via has a length different from a preset first width. 
     Aspects of the present disclosure are not limited to the those explicitly set forth above, and other aspects of the present disclosure will become more apparent to those of ordinary skill in the art to which the present disclosure pertains upon thorough review of the detailed description of the present inventive concepts given below. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other aspects and features of the present disclosure will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings, in which: 
         FIG. 1  is a flowchart showing operations of methods for fabricating integrated circuits that include one or more of a plurality of standard cells, according to some example embodiments. 
         FIG. 2  is a diagram showing aspects of a layout of an example integrated circuit, according to some example embodiments. 
         FIG. 3  is a diagram showing a cross section of the example integrated circuit of  FIG. 2 . 
         FIGS. 4 and 5  show layouts of the example integrated circuit according to some example embodiments. 
         FIGS. 6 to 8  show layouts of the example integrated circuit according to some example embodiments. 
         FIG. 9  is a block diagram showing an example of a computing system that includes a memory that stores a program, according to some example embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     In the following explanation, integrated circuits of various example embodiments are provided. An integrated circuit may be formed on a substrate (e.g., substrate  1  of  FIG. 2 ), for example, a semiconductor substrate. The integrated circuit has a layout that includes various standard cells. The standard cells are integrated circuit structures that are predesigned for repeated use in the design of individual integrated circuits. Effective integrated circuit design layouts include various pre-designed standard cells and pre-defined rules related to placement of standard cells to enhance circuit performance and reduce a circuit area. In some instances, the pre-defined rules may be related to various aspects of a fabrication process for the integrated circuits. 
     The integrated circuit according to some example embodiments includes one or more standard cells placed in the integrated circuit layout by the pre-defined rules. Such standard cells are used repeatedly in the design of integrated circuits. Therefore, the standard cells are pre-designed according to fabricating technology, and stored in the standard cell library. An integrated circuit designer may search for such standard cells, include them in the integrated circuit design, and place them in the integrated circuit layout according to a pre-defined placement rules. 
     The standard cell may include various basic circuit devices (e.g., logic gates), like an inverter, an AND, a NAND, an OR, a XOR, and a NOR, which may be frequently used in the digital circuit design of electronic devices. Examples of electronic devices include central processing units (CPU), graphic processing units (GPU), and system-on-chip (SOC) designs. Standard cells may include other devices frequently used in circuit blocks, such as a flip-flop and a latch. 
     A standard cell according to some example embodiments may be included in each functional block of a System On Chip (SoC) to improve integration and improve performance and reliability of a designed SoC. 
     Hereinafter, embodiments according to the present inventive concepts will be described with reference to the accompanying drawings. 
       FIG. 1  is a flowchart showing operations of methods for fabricating integrated circuits that include one or more of a plurality of standard cells, according to some example embodiments. 
     A standard cell library  1  may include information on a plurality of standard cells, for example, functional information, characteristic information, layout information and the like. 
     In step S 20 , a logic synthesis operation for generating netlist data  2  from register-transfer level (RTL) data S 10  may be performed. For example, a semiconductor design tool (e.g., a logic synthesis tool) may generate data  2  including a bitstream or a netlist, by performing a logic synthesis from RTL data S 10  created as a VHDL (VHSIC Hardware Description Language) and a HDL (Hardware Description Language) such as Verilog, with reference to the standard cell library  1 . 
     In step S 30 , a Place &amp; Routing (P &amp; R) operation for generating the layout data  3  from the netlist data  2  may be performed. The place &amp; routing step S 30  may include a plurality of steps. 
     According to some example embodiments, the place &amp; routing step S 30  may include performing an operation of selectively placing the standard cells. A semiconductor design tool (e.g., the P&amp;R tool) may place a plurality of standard cells from the netlist data  2  with reference to the standard cell library  1 . 
     According to some embodiments, the place &amp; routing step S 30  may include performing an operation of generating an interconnection. The interconnection may electrically connect an output fin and an input fin of the standard cell, and may include, for example, at least one via and at least one conductive pattern. By generating the interconnection, the standard cells may be routed. 
     According to some example embodiments, the place &amp; routing step S 30  may include performing an operation of generating a layout draft of the layout data  3 . The layout data  3  may have a format such as a Graphic Design System II (GDSII) format, and may include geometric information of the standard cells and interconnections. 
     According to some example embodiments, the place &amp; routing step S 30  may include checking portions to be revised in the layout draft to make revisions on the interconnections. The revised layout data may be finally settled. 
     In step S 40 , an operation of manufacturing a mask may be performed. For example, a pattern formed on a plurality of layers may be defined according to the layout data  3 , and at least one mask (or photomask) for forming patterns of each of the plurality of layers may be manufactured. 
     In step S 50 , an operation of fabricating an integrated circuit may be performed. For example, the integrated circuit may be fabricated, by patterning a plurality of layers, using at least one mask manufactured in step S 40 . 
     According to some example embodiments, a front-end-of-line (FEOL) process may be performed in step S 50 . The FEOL process may refer to a process of forming individual elements for example, transistors, capacitors, and resistors, on a substrate in a process of fabricating the integrated circuit. For example, the FEOL process may include a step of planarizing and cleaning a wafer, a step of forming a trench, a step of forming a well, a step of forming a gate line, a step of forming a source and a drain, and the like. 
     A BEOL (back-end-of-line) process may be performed in step S 50  according to some example embodiments. The BEOL process may refer to a process of connecting individual elements, for example, transistors, capacitors, and resistors to each other in a process of fabricating the integrated circuit. For example, the BEOL process may include a step of silicidation of a gate, a source and a drain region, a step of adding a dielectric, a planarizing step, a step of forming holes, a step of adding a metal layer, a step of forming a via, a step of forming a passivation layer and the like. Thereafter, the integrated circuit may be packaged in a semiconductor package and used as a component of various applications. 
       FIG. 2  is a diagram showing aspects of a layout of an example integrated circuit according to some example embodiments, and  FIG. 3  is a diagram showing a cross section of the example integrated circuit of  FIG. 2 . 
     Referring to  FIGS. 2 and 3 , an active pattern AC may extend in a first direction D 1  on a substrate SUB having a plane parallel to a horizontal plane. The active pattern AC may include semiconductors such as silicon (Si) or germanium (Ge), or compound semiconductors such as silicon-germanium (SiGe), silicon carbide (SiC), gallium arsenide (GaAs), indium arsenide (InAs) and indium phosphide (InP). The active pattern AC may include a conductive region, for example, an impurity-doped well, and an impurity-doped structure. 
     The active pattern AC may be separated into a first active region AC 1  and a second active region AC 2 . The active regions AC 1  and AC 2  may be spaced apart from each other at a cell boundary B between the adjacent standard cells. 
     Gate lines G 1  and G 2  may extend in a second direction D 2  that is perpendicular to the first direction D 1 . The gate lines G 1  and G 2  may extend on the active pattern AC (e.g., the gate lines G 1  and G 2  may overlap the active pattern AC). The first gate line G 1  may extend on the first active region AC 1 , and the second gate line G 2  may extend on the second active region AC 2 . A respective source/drain region SD may be formed on one side of each of the gate lines G 1  to G 2  on the active pattern AC. In other words, a first source/drain region SD 1  may be formed on one side of the first gate line G 1  on the first active region AC 1 , and a second source/drain region may be formed on one side of the second gate line G 2  on the second active region AC 2 . Conductive lines MW 1  and MW 2  may extend in the first direction D 1  on a plane separated from the upper surfaces of the gate lines G 1  to G 2 . 
     Lower surfaces of source/drain contacts CA 1  and CA 2  may be connected respectively to the source/drain regions SD 1  and SD 2 , and upper surfaces thereof may be connected to respective source/drain vias LA 1  and LA 2 . Lower surfaces of the source/drain vias LA 1  and LA 2  may be connected respectively to the upper surfaces of the source/drain contacts CA 1  and CA 2 , and upper surfaces of the source/drain vias LA 1  and LA 2  may be connected respectively to the conductive lines MW 1  and MW 2 . 
     Although it is not shown, the gate lines G 1  to G 2  may include a stacked structure of TiAlC/TiN/W, a stacked structure of TiN/TaN/TiAlC/TiN/W or a stacked structure of TiN/TaN/TiN/TiAlC/TiN/W, according to some example embodiments. 
     According to some example embodiments, the integrated circuit may include a plurality of conductive lines parallel to each other in the first direction D 1 , and source/drain contacts and gate contacts may be connected to at least one of the plurality of conductive lines. For example, as shown in  FIG. 2 , the conductive lines MW 1  and MW 2  may extend in the first direction D 1 , and the source/drain contacts CA 1  and CA 2  may be connected respectively to the conductive lines MW 1  and MW 2  by the source/drain vias LA 1  and LA 2 . 
     As best seen in  FIG. 2 , a first standard cell CELL 1  and a second standard cell CELL 2  may be placed to face each other as adjacent cells on the basis of the cell boundary B. The first standard cell CELL 1  may include the first active region AC 1 , the first gate line G 1 , the first source/drain region SD 1 , the first source/drain contact CAL the first source/drain via LA 1 , and the first conductive line MW 1 . The second standard cell CELL 2  may include the second active region AC 2 , the second gate line G 2 , the second source/drain region SD 2 , the second source/drain contact CA 2 , the second source/drain via LA 2 , and the second conductive line MW 2 . For convenience of explanation, a distance from a tip of the conductive line MW 1  of the standard cell CELL 1  to the cell boundary B is assumed to be d 1 , and a distance from a tip of the conductive line MW 2  of the standard cell CELL 2  to the cell boundary B is assumed to be d 2 . Also, a distance from the tip of the conductive line MW 1  of the standard cell CELL 1  to the intersection of the conductive line MW 1  with the source/drain via LA 1  is assumed to be W 1 , and a distance from the tip of the conductive line MW 2  of the standard cell CELL 2  to the intersection of the conductive line MW 2  with the source/drain via LA 2  is assumed to be W 2 . 
     According to design rules for integrated circuit design, various rules, structures, and widths, lengths, heights, etc. of structures for place &amp; routing may be specified. 
     The length, width, and height of the conductive line may also be defined in the design rules according to some example embodiments. As an example, a length of W 1  and/or W 2  may be previously set to a predetermined value. The predetermined value of the length W 1  and/or W 2  may be dependent on various factors, such as a spaced distance from the tip of the conductive line of the adjacent cell, the distance from the cell boundary, the cell structure below the conductive line, and the like. 
     With reference to steps S 30 , S 40 , and S 50  of  FIG. 1 , after MW 1  and MW 2  on the same line in the process order considering the mask of step S 40  are formed as a single conductive line, the conductive line between adjacent standard cells may be cut to a predetermined pattern C at the cell boundary B. 
     According to some example embodiments, when there is a cut pattern C between the conductive line and the conductive line on the adjacent same line, W 1  of the conductive line may be set to be a relatively short length, and when there is no cut pattern C, W 1  of the conductive line may be set to be a relatively long length. Considering the operation reliability of the integrated circuit, it is advantageous that W 1  of the conductive line be set to be a long length or the relatively long length. However, as the integrated circuit process becomes finer, in principle, the design rule may be set to be as short of a length as possible (e.g., to a minimum length such that there is no problem in operation), and may be set to be long only in exceptional cases. 
     According to some example embodiments, at the time of generating a layout draft, when a spaced distance (measured from Tip to Tip, or d 1 +d 2 ) between the tip of the conductive line MW 1  of standard cell CELL 1  and the tip of the conductive line MW 2  of standard cell CELL 2  is 24 nm, a cut pattern C between the conductive lines may be placed. That is, when the distance between each of the tips of the conductive lines MW 1  and MW 2  of the standard cells CELL 1  and CELL 2  and the cell boundary B is 12 nm, the length of the distances W 1  and W 2  from the tip of the respective conductive line MW 1 /MW 2  to the intersection of the conductive line MW 1 /MW 2  with the respective source/drain via LA 1 /LA 2  may be defined, in principle, as a short length, e.g., 5 nm. As such, by satisfying the design rule conditions that take into consideration the design, potential process errors, and an influence on an adjacent cell according to the formation of the source/drain vias LA 1 /LA 2 , when checking whether the design rule of the final layout data is satisfied, no error occurs. 
     Incidentally, as shown, although the spaced distance (Tip to Tip, d 1 +d 2 ) from the tip of the conductive line MW 1  of the standard cell CELL 1  to the tip of the conductive line MW 2  of the standard cell CELL 2  may be at least 24 nm, if the length of W 1  and W 2  is set as a length of 9 nm as an another example, the conductive line may too approach the conductive line of the adjacent cell on the basis of the cell boundary B. In this case, a problem may occur in the operation reliability of the integrated circuit, and an error may occur when checking whether the design rule of the final layout data is satisfied. Specifically, checking as to whether the design rule is satisfied will be explained in  FIGS. 4 and 5 . 
       FIGS. 4 and 5  show examples of layouts of the example integrated circuit according to some example embodiments. 
     In  FIG. 4 , the distance d 1  from the tip of the conductive line MW 1  of the standard cell CELL 1  to the cell boundary B is assumed to be 52 nm, and the distance d 2  from the tip of the conductive line MW 2  of the standard cell CELL 2  to the cell boundary B is assumed to be 12 nm. That is, the length of d 1  is assumed to be longer than that d 2 . 
     In the shown example, since the length of d 1  is relatively long, the tip of the conductive line MW 2  may be able to further extend in the direction of the cell boundary B according to the exception of the design rule. That is, the length of W 2  may be further elongated. 
     Incidentally, in the place &amp; routing step (S 30  of  FIG. 1 ), when the length of W 1  and W 2  of the standard cell CELL 1  and the standard cell CELL 2  is each set to 5 nm only according to the principle of the design rule, an error may occur when checking whether the design rule of the final layout is satisfied. 
     In  FIG. 5 , the standard cell CELL 1  may have a source/drain via LA 11  and a source/drain via LA 12  placed on both sides of the gate line G 1 , and may include a conductive line MW 1  that extends in the first direction D 1  and simultaneously connects the source/drain via LA 11  and the source/drain via LA 12 . The standard cell CELL 2  may have a source/drain via LA 21  and a source/drain via LA 22  placed on both sides of the gate line, and may include a conductive line MW 2  that extends in the first direction D 1  and simultaneously connects the source/drain via LA 21  and the source/drain via LA 22 . 
     In this case, considering the design rule regulation of the length of W 1  and W 2  and the spaced distance (d 1 +d 2 ) at the cell boundary B, when a space between the adjacent source/drain via LA 11  and source/drain via LA 21  becomes too narrow, a design rule error may occur when the source/drain via LA 11  and the source/drain via LA 21  are placed at the same time. 
       FIGS. 6 to 8  show examples of layouts of the example integrated circuit according to some example embodiments. 
     A description will be given with reference to  FIGS. 6 to 8  to prevent or avoid occurrences of design rule errors and to improve operation reliability of integrated circuits. According to some example embodiments, the place &amp; routing step (S 30  of  FIG. 1 ) of the integrated circuit first may generate a layout draft as a first place &amp; routing step, and may modify and settle the layout as a second place &amp; routing step after checking whether the design rules are satisfied. 
     Referring to  FIG. 6 , the conductive lines MW 1  and MW 2  may be first placed on the upper surfaces of the source/drain vias LA 1  and LA 2  according to some example embodiments. Subsequently, the conductive line may be cut by the cut pattern C on the basis of the cell boundary B, and may be separated into the conductive lines of the standard cell CELL 1  and the standard cell CELL 2 . In this case, W 1  of the conductive line MW 1  and W 2  of the conductive line MW 2  of the layout draft may be cut by the cut pattern to a length according to the principle that is preset in the design rule. In the example shown, it is assumed that d 1  and d 2  are each 12 nm and W 1  and W 2  are placed at 5 nm. 
     Thereafter, it is possible to check whether the design rules are satisfied. For example, by checking the design rules of the cell boundary B region, it is possible to check whether the spaced distance (d 1 +d 2 ) between the conductive lines is equal to or greater than a preset threshold value. 
     When the spaced distance is equal to or greater than a preset first threshold value (24 nm), the length of W 1  and W 2  is determined to satisfy the design rules, and the final layout may be settled as in the draft layout. 
     Referring to  FIG. 7 , the conductive lines MW 1  and MW 2  may be placed on the upper surfaces of the source/drain vias LA 1  and LA 2  according to some example embodiments. Subsequently, the cut pattern C of the conductive line may be formed on the basis of the source/drain vias LA 1  and LA 2 . 
     W 1  of the conductive line MW 1  and W 2  of the conductive line MW 2  of the layout draft may be cut by a cut pattern to a length according to the principle that is preset in the design rules. In the shown example, W 1  and W 2  are assumed to be placed at 5 nm as an example. 
     Thereafter, it is possible to check whether the design rules are satisfied. For example, by checking the design rule of the cell boundary B region, it is possible to check whether the spaced distance (d 1 +d 2 ) between the conductive lines is equal to or greater than a preset threshold value. 
     When the spaced distance is equal to or greater than the predetermined first threshold value (24 nm) and the distance of d 1  is a second threshold value (52 nm), it is determined that the length (5 nm) of W 2  does not satisfy the design rules, and the layout draft may be modified. 
     Since a distance of d 1  is equal to or greater than the second threshold value, the layout draft may be modified so that the length of W 2  extends according to the exception of the design rule. For example, the length of W 2  may be extended from 5 nm to 9 nm. 
     The place &amp; routing step may settle the final layout with the modified layout. 
     Referring to  FIG. 8 , the conductive lines MW 1  and MW 2  may be placed on the upper surfaces of the source/drain vias LA 1  and LA 2  according to some example embodiments. Subsequently, the cut pattern C of the conductive line may be formed on the basis of the source/drain vias LA 1  and LA 2 . 
     W 1  of the conductive line MW 1  and W 2  of the conductive line MW 2  of the layout draft may be cut by a cut pattern to a length according to the principle that is preset in the design rules. In the shown example, W 1  and W 2  are assumed to be placed at 5 nm as an example. 
     Thereafter, it may be possible to check whether the design rules are satisfied. For example, by checking the design rules of the cell boundary B region, it is possible to confirm whether the spaced distance (d 1 +d 2 ) between the conductive lines is equal to or greater than the preset threshold value. 
     If the spaced distance is equal to or greater than the predetermined first threshold value (24 nm) and the distance of d 1  and d 2  is equal to or greater than 52 nm, it is determined that the lengths of W 1  and W 2  do not satisfy the design rules, and the layout draft may be modified. 
     Since the distance of d 1  is equal to or greater than the second threshold value, the layout draft may be modified so that the length of W 1  or W 2  extends according to the exception of the design rules. For example, the length of W 1  may extend from 5 nm to 9 nm or more. In this case, a connecting fin for connection to another conductive line may be further placed on the extended conductive line W 1 ′. 
     The place &amp; routing step may settle the final layout with the changed layout. 
       FIG. 9  is a block diagram showing a computing system including a memory that stores a program according to some embodiments. 
     At least some of the steps and operations involved in methods for fabricating the integrated circuits (e.g., the method shown and described with reference to  FIGS. 1 to 8 ) according to some example embodiments may be performed in the computing system  10 . 
     The computing system  10  may be a fixed computing system such as a desktop computer, a workstation, and a server, or may be a portable computing system such as a laptop computer. As shown in  FIG. 9 , the computing system  10  may include a processor  11 , I/O devices  12 , a network interface  13 , a RAM (random access memory)  14 , a ROM (read only memory)  15 , and a storage device  16 . The processor  11 , the I/O devices  12 , the network interface  13 , the RAM,  14 , the ROM  15  and the storage device  16  may be connected to the bus  17 , and may communicate with each other through the bus  17 . 
     The processor  11  may be called a processing unit, and may include at least one core capable of executing an arbitrary command set (e.g., IA-32 (Intel Architecture-32), 64-bit extension, IA-32, x86-64, PowerPC, Sparc, MIPS, ARM, IA-64, etc.) such as, for example, a micro-processor, an AP (application processor), a DSP (digital signal processor), and a GPU (graphic processing unit). For example, the processor  11  may access the memory, that is, the RAM  14  or the ROM  15 , through the bus  17 , and may execute commands stored in the RAM  14  or the ROM  15 . As shown in  FIG. 9 , the RAM  14  may store a program  20  according to an exemplary embodiment of the present disclosure or at least a part thereof, and the program  20  may cause the processor  11  to perform at least some of the steps involved in the method for fabricating the integrated circuit. That is, the program  20  may include a plurality of commands capable of being executed by the processor  11 , and the plurality of commands included in the program  2000  may cause the processor  11  to perform, for example, the logic synthesis operation of step S 20  of  FIG. 1  and/or the P&amp;R (place &amp; routing) operations of step S 30 . 
     The storage device  16  may be configured to retain or maintain stored data even if the power supplied to the computing system  10  is cut off. For example, the storage device  16  may include a non-volatile memory device, and may also include a storage medium such as a magnetic tape, an optical disk, and a magnetic disk. Also, the storage device  16  may also be attachable to and detachable from the computing system  10 . The storage device  16  may also store the program  20  according to an exemplary embodiment of the present disclosure, and before the program  20  is executed by the processor  11 , the program  20  or at least some thereof may be loaded into the RAM  14  from the storage device  16 . Alternatively, the storage device  16  may store files written in a program language, and the program  20  generated by a compiler from the file or at least some thereof may be loaded into the RAM  14 . Further, in some example embodiments, the storage device  16  may store a database (not shown in  FIG. 9 ), and the database may include information necessary for designing an integrated circuit, for example, the standard cell library  1  of  FIG. 1 . 
     The storage device  16  may also store data to be processed by the processor  11  or data processed by the processor  11 . That is, the processor  11  may generate data by processing the data stored in the storage device  16  according to the program  20 , and may store the generated data in the storage device  16 . For example, the storage device  16  may also store the RTL data S 10 , the netlist data  2  and/or the layout data  3 . 
     The I/O devices  12  may include an input device such as a keyboard and a pointing device, and may include an output device such as a display device and a printer. For example, a user may trigger the execution of the program  20  by the processor  11  through the I/O devices  12 , may input the RTL data S 10  and/or the netlist data  2  of  FIG. 1 , and may confirm the layout data  3  of  FIG. 1   
     The network interface  13  may provide an access to a network outside the computing system  10 . For example, the network may include a plurality of computing systems and communication links, and the communication links may include wired links, optical links, wireless links or any other type of link. 
     In concluding the detailed description, those skilled in the art will appreciate that many variations and modifications may be made to the example embodiments disclosed herein without substantially departing from the principles of the present inventive concepts. Therefore, the disclosed example embodiments of the inventive concepts are used in a generic and descriptive sense only and not for purposes of limitation.