Patent Publication Number: US-2022216120-A1

Title: Pattern design for integrated circuits and method for inspecting the pattern design for integrated circuits

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This is a Continuation of U.S. application Ser. No. 16/596,657, filed Oct. 8, 2019, and a claim of priority under 35 U.S.C. § 119 is made to Korean Patent Application No. 10-2019-0045659, filed on Apr. 18, 2019 in the Korean Intellectual Property Office, the entire contents of which are hereby incorporated by reference. 
    
    
     BACKGROUND 
     The present inventive concepts relate to pattern design for integrated circuits and a method for inspecting the pattern design for integrated circuits. 
     Design rules, contact areas and critical dimensions, among other physical characteristics of semiconductor devices, have continuously been reduced as the degree of integration of integrated circuits fabricated using semiconductors has improved. Consequently, electronic circuits formed on substrates have become more complicated and circuit packing density of integrated circuits in substrates has gradually increased. The high circuit packing density of integrated circuits requires high operational precision during processing/fabrication of circuit units. Accordingly, there is a need for more sophisticated detection technology for detecting defects in electronic circuits. 
     SUMMARY 
     Embodiments of the inventive concepts are directed to providing a pattern design for integrated circuits and a method for inspecting the pattern design for integrated circuits. 
     Embodiments of the inventive concepts provide a pattern design including a first floating conductive line; a second floating conductive line; and a grounded conductive line disposed between the first floating conductive line and the second floating conductive line. The first floating conductive line, the second floating conductive line, and the grounded conductive line are divided into a main pad region, a plurality of subregions, a plurality of sub-pad regions, and a ground region. The main pad region is positioned at a first end portion of the pattern design. The ground region is positioned at a second end portion of the pattern design. The plurality of subregions and the plurality of sub-pad regions are positioned between the main pad region and the ground region. 
     Embodiments of the inventive concepts further provide a pattern design including a first comb line; a second comb line; and a serpentine line disposed between the first comb line and the second comb line. The first comb line includes a first main line extending horizontally and a plurality of first branch lines extending perpendicularly from the first main line. The second comb line includes a second main line extending horizontally and a plurality of second branch lines extending perpendicularly from the second main line. The serpentine line extends between the plurality of first branch lines and the plurality of second branch lines in a serpentine shape. The first comb line includes a first main pad disposed at a first end portion of the first main line, and a plurality of first sub-pads respectively disposed at end portions of different single branch lines from among the plurality of first branch lines. The second comb line includes a second main pad disposed at a first end portion of the second main line, and a plurality of second sub-pads respectively disposed at end portions of different single branch lines from among the plurality of second branch lines. The serpentine line includes a third main pad disposed at a first end portion of the serpentine line and third sub-pads disposed between the plurality of first sub-pads and the plurality of second sub-pads. 
     Embodiments of the inventive concepts still further provide a defect inspection method of a pattern design for an electronic beam inspection apparatus including a controller. The defect inspection method includes scanning, by the controller, a main pad region formed at a first end portion of a pattern design using a particle beam and generating main pad information; scanning, by the controller, a first sub-pad region formed at a first end portion of a first subregion of the pattern design using the particle beam and generating first sub-pad information; and determining, by the controller, a state of the pattern design based on the main pad information and the first sub-pad information. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objects and features of the inventive concepts will become apparent in view of the following detailed description made with reference to the accompanying. 
         FIG. 1  illustrates a conceptual diagram showing pattern designs disposed along scribe lanes according to embodiments of the inventive concepts. 
         FIG. 2  illustrates a conceptual diagram showing pattern designs disposed inside a semiconductor chip according to embodiments of the inventive concepts. 
         FIG. 3  illustrates a conceptual diagram showing a pattern design disposed in a test vehicle according to embodiments of the inventive concepts. 
         FIG. 4  illustrates a conceptual diagram showing a layout structure of a plurality of pattern designs according to embodiments of the inventive concepts. 
         FIG. 5  illustrates a conceptual diagram showing a vertical pattern design according to embodiments of the inventive concepts. 
         FIG. 6  illustrates a conceptual diagram showing a horizontal pattern design according to embodiments of the inventive concepts. 
         FIG. 7A  illustrates a conceptual diagram showing voltage contrast images of a main pad of a pattern design when pattern designs are in a normal state, according to embodiments of the inventive concepts. 
         FIG. 7B  illustrate a conceptual diagram showing voltage contrast images when a defect occurs in a third conductive line of a second pattern design, according to embodiments of the inventive concepts. 
         FIG. 7C  illustrates a conceptual diagram showing voltage contrast images when a defect occurs in a second conductive line of a second pattern design, according to embodiments of the inventive concepts. 
         FIG. 8A  illustrates a conceptual diagram showing voltage contrast images of first sub-pads when a first subregion is in a normal state, according to embodiments of the inventive concepts. 
         FIG. 8B  illustrates a conceptual diagram showing voltage contrast images of second sub-pads when a third conductive line of a second subregion is in a defective state, according to embodiments of the inventive concepts. 
         FIG. 8C  illustrates a conceptual diagram showing voltage contrast images of second sub-pads when a second conductive line of a second subregion is in a defective state, according to embodiments of the inventive concepts. 
         FIG. 9A  illustrates a conceptual diagram showing voltage contrast images of a second subregion when the second subregion is in a normal state, according to embodiments of the inventive concepts. 
         FIG. 9B  illustrates a conceptual diagram showing voltage contrast images of a second subregion when a second conductive line of the second subregion is in a defective state, according to embodiments of the inventive concepts. 
         FIG. 9C  illustrates a conceptual diagram showing voltage contrast images of a second subregion when a second conductive line and a third conductive line of the second subregion are short-circuited, according to embodiments of the inventive concepts. 
         FIG. 10  illustrates an electron beam inspection apparatus according to embodiments of the inventive concepts. 
         FIG. 11  illustrates a flow chart of a defect inspection method for pattern design according to embodiments of the inventive concepts. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, embodiments of the inventive concepts will be described in detail and clearly to such an extent that those of ordinary skill in the art may easily implement the inventive concepts. 
     As is traditional in the field of the inventive concepts, embodiments may be described and illustrated in terms of blocks which carry out a described function or functions. These blocks, which may be referred to herein as units or modules or the like, are physically implemented by analog and/or digital circuits such as logic gates, integrated circuits, microprocessors, microcontrollers, memory circuits, passive electronic components, active electronic components, optical components, hardwired circuits and the like, and may optionally be driven by firmware and/or software. The circuits may, for example, be embodied in one or more semiconductor chips, or on substrate supports such as printed circuit boards and the like. The circuits constituting a block may be implemented by dedicated hardware, or by a processor (e.g., one or more programmed microprocessors and associated circuitry), or by a combination of dedicated hardware to perform some functions of the block and a processor to perform other functions of the block. Each block of the embodiments may be physically separated into two or more interacting and discrete blocks without departing from the scope of the inventive concepts. Likewise, the blocks of the embodiments may be physically combined into more complex blocks without departing from the scope of the inventive concepts. 
       FIG. 1  illustrates a conceptual diagram showing pattern designs disposed along scribe lanes according to embodiments of the inventive concepts. 
     Referring to  FIG. 1 , semiconductor chips  110 ,  120 ,  130 ,  140 ,  150 ,  160 ,  170 ,  180  and  190  (i.e., semiconductor chips  110  to  190 ) on wafer  100  may be disposed to be spaced apart from each other with scribe lanes  101 ,  102 ,  103  and  104  (i.e., scribe lanes  101  to  104  indicated by dashed lines) as boundaries. Pattern designs for inspecting defects in the semiconductor chips  110  to  190  may be disposed in the scribe lanes  101  to  104 . For example, the pattern designs  111   a,    111   b,    111   c,    111   d  and  111   e  disposed around semiconductor chip  110 , may be disposed on wafer  100  around semiconductor chips  110  to  190  adjacent to the scribe lanes, for electrical connection (not shown) with the corresponding semiconductor chips. 
       FIG. 2  illustrates a conceptual diagram showing pattern designs disposed inside a semiconductor chip according to embodiments of the inventive concepts. 
     Referring to  FIG. 2 , various types of circuit patterns  210 ,  220 ,  230 ,  240 ,  250 ,  260 ,  270 ,  280  and  290  (i.e., circuit patterns  210  to  290 ) may be formed inside a semiconductor chip  200 . Pattern designs  201 ,  202 ,  203  and  204  (i.e., pattern designs  201  to  204 ) for inspecting defects in the semiconductor chip  200  may be disposed in some regions of the semiconductor chip  200 . For example, the pattern designs  201  to  204  may be disposed adjacent to edges of the semiconductor chip  200 . 
       FIG. 3  illustrates a conceptual diagram showing a pattern design disposed in a test vehicle according to embodiments of the inventive concepts. 
     Referring to  FIG. 3 , a test vehicle  300  may include various types of test circuit pattern blocks  310 ,  320 ,  330 ,  340 ,  350 ,  360 ,  370  and  380  (i.e., test circuit pattern blocks  310  to  380 ). For example, the test circuit pattern blocks  310  to  380  may include various logic patterns for monitoring various processes. A pattern design  381  for inspecting defects in the test vehicle  300  may be disposed inside one of the test circuit pattern blocks  310  to  380 . For example, pattern design  381  is shown in  FIG. 3  as disposed inside test circuit pattern block  380 , but in other embodiments pattern design  381  may be disposed inside any other of test circuit pattern blocks  310  to  370 . 
       FIG. 4  illustrates a conceptual diagram showing a layout structure of a plurality of pattern designs according to embodiments of the inventive concepts. 
     Referring to  FIG. 4 , a plurality of pattern designs  410 ,  420 ,  430  and  440  (i.e.,  410  to  440 ) for inspecting defects may be disposed on one surface of one substrate  400 . The plurality of pattern designs  410  to  440  may be disposed to mirror to each other with respect to reference lines  401  and  402 . 
     For example, a first pattern design  410  and a second pattern design  420  may be horizontally reversed with reference to each other with respect to a first reference line  401 . 
     A third pattern design  430  and a fourth pattern design  440  may be horizontally reversed with reference to each other with respect to the first reference line  401 . 
     The first pattern design  410  and the third pattern design  430  may be vertically inverted with reference to each other with respect to a second reference line  402 . The second pattern design  420  and the fourth pattern design  440  may be vertically inverted with reference to each other with respect to the second reference line  402 . 
       FIG. 5  illustrates a conceptual diagram showing a vertical pattern design according to embodiments of the inventive concepts. 
     Referring to  FIG. 5 , a pattern design  500  may be a comb-serpentine pattern, which is a circuit pattern for testing. The pattern design  500  may include a first conductive line  510 , a second conductive line  520 , and a third conductive line  530  disposed between the first conductive line  510  and the second conductive line  520 . 
     The first conductive line  510  may be referred to as a first comb line and may be characterized as having a first comb shape. The second conductive line  520  may be referred to as a second comb line and may be characterized as having a second comb shape. The third conductive line  530  may be referred to as a serpentine line. 
     The first conductive line  510  may include a first main line  511 , a plurality of branch lines  512   a,    512   b,    512   c,    512   d,    512   e,    512   f,    512   g,    512   h,    512   i,    512   j,    512   k,    512   l ,  512   m  and  512   n  (i.e., a plurality of branch lines  512   a  to  512   n ), a first main pad  513 , and a plurality of sub-pads  514   a  and  514   b.  The first main line  511  may have a horizontally elongated shape. The plurality of branch lines  512   a  to  512   n  may have a shape extending perpendicularly from the first main line  511  toward the second conductive line  520 . The first main pad  513  may be formed at a first end portion of the first conductive line  510 . Each of the plurality of sub-pads  514   a  and  514   b  may be formed at a first end portion of at least one of the plurality of branch lines  512   a  to  512   n.  A second end portion of the first conductive line  510  may be floating. 
     Each of 1 st -1 to 1 st -4 branch lines  512   a  to  512   d  may be longer than the 1 st -5 branch line  512   e.  A first end portion of the 1 st -5 branch line  512   e  may be connected to a 1 st -1 sub-pad  514   a.  The 1 st -1 sub-pad  514   a  may be formed at the first end portion of the 1 st -5 branch line  512   e.    
     Each of 1 st -6 to 1 st -9 branch lines  512   f  to  512   i  may be longer than a 1 st -10 branch line  512   j.  A first end portion of the 1 st -10 branch line  512   j  may be connected to the 1 st -2 sub-pad  514   b.  The 1 st -2 sub-pad  514   b  may be formed at the first end portion of the 1 st -10 branch line  512   j.    
     Each of 1 st -11 to 1 st -14 branch lines  512   k  to  512   n  may be longer than the 1 st -10 branch line  512   j.    
     The second conductive line  520  may include a second main line  521 , a plurality of branch lines  522   a,    522   b,    522   c,    522   d,    522   e,    522   f,    522   g,    522   h,    522   i,    522   j,    522   k,    522   l,    522   m  and  522   n  (i.e., a plurality of branch lines  522   a  to  522   n ), a second main pad  523 , and a plurality of sub-pads  524   a  and  524   b.    
     The second main line  521  may have a horizontally elongated shape. The second main line  521  may be parallel to the first main line  511 . The plurality of branch lines  522   a  to  522   n  may have a shape extending perpendicularly from one side of the second main line  521  toward the first conductive line  510 . The second main pad  523  may be formed at a first end portion of the second conductive line  520 . Each of the plurality of sub-pads  524   a  and  524   b  may be formed at a first end portion of at least one of the plurality of branch lines  522   a  to  522   n.  A second end portion of the second conductive line  520  may be floating. 
     The plurality of branch lines  522   a  to  522   n  of the second conductive line  520  may be interdigitated to be coplanar with the plurality of branch lines  512   a  to  512   n  of the first conductive line  510 . For example, a 2 nd -1 branch line  522   a  may be disposed between the 1 st -1 branch line  512   a  and the 1 st -2 branch line  512   b.  A 2 nd -2 branch line  522   b  may be disposed between the 1 st -2 branch line  512   b  and a 1 st -3 branch line  512   c.  A 2 nd -3 branch line  522   c  may be disposed between the 1 st -3 branch line  512   c  and the 1 st -4 branch line  512   d . A 2 nd -4 branch line  522   d  may be disposed between the 1 st -4 branch line  512   d  and the 1 st -5 branch line  512   e.  A 2 nd -5 branch line  522   e  may be disposed between the 1 st -5 branch line  512   e  and the 1 st -6 branch line  512   f.  A first end portion of the 2 nd -5 branch line  522   e  may be connected to a 2 nd -1 sub-pad  524   a.  The 2 nd -1 sub-pad  524   a  may be formed at the first end portion of the 2 nd -5 branch line  522   e.  Each of the 2 nd -1 to 2 nd -4 branch lines  522   a  to  522   d  may be longer than the 2 nd -5 branch line  522   e.    
     A 2 nd -6 branch line  522   f  may be disposed between the 1 st -6 branch line  512   f  and the 1 st -7 branch line  512   g.  A 2 nd -7 branch line  522   g  may be disposed between the 1 st -7 branch line  512   g  and the 1 st -8 branch line  512   h.  A 2 nd -8 branch line  522   h  may be disposed between the 1 st -8 branch line  512   h  and the 1 st -9 branch line  512   i.  A 2 nd -9 branch line  522   i  may be disposed between the 1 st -9 branch line  512   i  and the 1 st -10 branch line  512   j.  A 2 nd -10 branch line  522   j  may be disposed between the 1 st -10 branch line  512   j  and a 1 st -11 branch line  512   k.  A first end portion of the 2 nd -10 branch line  522   j  may be connected to a 2 nd -2 sub-pad  524   b.  The 2 nd -2 sub-pad  524   b  may be formed at the first end portion of the 2 nd -10 branch line  522   j.  Each of the 2 nd -6 to 2 nd -9 branch lines  522   f  to  522   i  may be longer than the 2 nd -10 branch line  522   j.    
     A 2 nd -11 branch line  522   k  may be disposed between the 1 st -11 branch line  512   k  and a 1 st -12 branch line  5121 . A 2 nd -12 branch line  5221  may be disposed between the 1 st -12 branch line  5121  and a 1 st -13 branch line  512   m.  A 2 nd -13 branch line  522   m  may be disposed between the 1 st -13 branch line  512   m  and a 1 st -14 branch line  512   n.  A 2 nd -14 branch line  522   n  may be disposed adjacent to one side surface of the 1 st -14 branch line  512   n.  Each of 2 nd -11 to 2 nd -14 branch lines  522   k  to  522   n  may be longer than the 2 nd -10 branch line  522   j.    
     The third conductive line  530  may include a third main line  531 , a third main pad  533 , a plurality of sub-pads  534   a  and  534   b,  and a ground  535 . The third main pad  533  may be formed at a first end portion of the third conductive line  530 . The third conductive line  530  may have a snaked shape extending in a serpentine manner along a separation space between the plurality of branch lines  512   a  to  512   n  of the first conductive line  510  and the plurality of branch lines  522   a  to  522   n  of the second conductive line  520 . For example, the third conductive line  530  may have a shape extending to be curved along the separation space between the plurality of branch lines  512   a  to  512   n  of the first conductive line  510  and the plurality of branch lines  522   a  to  522   n  of the second conductive line  520 . 
     The third conductive line  530  may be disposed to be spaced apart from the plurality of branch lines  512   a  to  512   n  of the first conductive line  510  and the plurality of branch lines  522   a  to  522   n  of the second conductive line  520 . A 3 rd -1 sub-pad  534   a  may be formed on the third conductive line  530  so as to be adjacent to the 1 st - 1  sub-pad  514   a  and the 2 nd -1 sub-pad  524   a.  A 3 rd -2 sub-pad  534   b  may be formed on the third conductive line  530  so as to be adjacent to the 1 st -2 sub-pad  514   b  and the 2 nd -2 sub-pad  524   b.  The ground  535  may be formed at a second end portion of the third conductive line  530 . 
     The pattern design  500  may be divided into a main pad region, first to third subregions, first and second sub-pad regions, and a ground region. For example, the main pad region may refer to a region in which the first to third main pads  513 ,  523 , and  533  of the pattern design  500  are formed. The main pad region may be characterized as positioned at a first end portion of pattern design  500 , and the ground region may be characterized as positioned at a second end portion of pattern design  500 , wherein the first end portion and the second end portion are at opposite ends of pattern design  500 . 
     The first sub-pad region may refer to a region in which the 1 st -1, 2 nd -1, and 3 rd -1 sub-pads  514   a,    524   a,  and  534   a  of the pattern design  500  are formed. The first subregion may refer to a region from the main pad region to the first sub-pad region of the pattern design  500 . 
     The second sub-pad region may refer to a region in which the 1 st -2, 2 nd -2 and 3 rd -2 sub-pads  514   b,    524   b,  and  534   b  of the pattern design  500  are formed. The second subregion may refer to a region from the first sub-pad region to the second sub-pad region of the pattern design  500 . 
     The third subregion may refer to a region from the second sub-pad region of the pattern design  500  to a second end portion of the pattern design  500 . 
       FIG. 6  illustrates a conceptual diagram showing a horizontal pattern design according to example embodiments of the inventive concepts. 
     Referring to  FIG. 6 , a horizontal pattern design  600  may include a plurality of conductive lines  610 ,  620 , and  630  similar to the conductive lines of the vertical pattern design  500 . 
     The horizontal pattern design  600  may be somewhat similar to the vertical pattern design  500 . For example, main pads  613 ,  623 , and  633  of the pattern design  600  may be identical or similar to the main pads  513 ,  523 , and  533  of the pattern design  500  of  FIGS. 5 . 1 st -1, 2 nd -1, and 3 rd -1 sub-pads  614   a,    624   a,  and  634   a  of the pattern design  600  may be identical or similar to the 1 st -1, 2 nd -1, and 3 rd -1 sub-pads  514   a,    524   a,  and  534   a  of the pattern design  500  of  FIG. 5 . A first end portion of the branch line  612   e  may be connected to a 1 st -1 sub-pad  614   a,  and a first end portion of the branch line  622   e  may be connected to a 2 nd -1 sub-pad  624   a.  Also, a first end portion of the branch line  612   j  may be connected to a 1 st -2 sub-pad  614   b,  and a first end portion of the branch line  622   j  may be connected to a 2 nd -2 sub-pad  624   b.    
     A structure of the plurality of conductive lines  610 ,  620 , and  630  of the horizontal pattern design  600  may be somewhat different from the structure of the plurality of conductive lines  510 ,  520 , and  530  of the vertical pattern design  500 . For example, first to third subregions of the horizontal pattern design  600  may be different from the first to third subregions of the vertical pattern design  500  of  FIG. 5 . The first subregion of the horizontal pattern design  600  may have a structure as follows. 
     A 1 st -2 branch line  612   b  of a first conductive line  610  may have a shape extending in a direction from a first end portion of a 1 st -1 branch line  612   a  to one side of the 1 st -1 branch line  612   a.    
     A 1 st -3 branch line  612   c  may have a shape extending in a direction from one point of the 1 st -1 branch line  612   a  to one side of the 1 st -1 branch line  612   a.  The 1 st -3 branch line  612   c  may be disposed between the 1 st -2 branch line  612   b  and a first main line  611  of first conductive line  610 . The 1 st -3 branch line  612   c  may be disposed to be spaced apart from the 1 st -2 branch line  612   b  and the first main line  611 . 
     A 1 st -4 branch line  612   d  may have a shape extending in a direction from another point of the 1 st -1 branch line  612   a  to one side of the 1 st -1 branch line  612   a.  The 1 st -4 branch line  612   d  may be disposed between the 1 st -3 branch line  612   c  and the first main line  611 . The 1 st -4 branch line  612   d  may be disposed to be spaced apart from the 1 st -3 branch line  612   c  and the first main line  611 . 
     A 2 nd -1 branch line  622   a  of a second conductive line  620  may be disposed between a second main pad  623  and the 1 st -1 branch line  612   a.  The 2 nd -1 branch line  622   a  may be disposed to be spaced apart from the second main pad  623  and the 1 st -1 branch line  612   a.    
     A 2 nd -2 branch line  622   b  may have a shape extending in a direction from a first end portion of the 2 nd -1 branch line  622   a  to one side of the 2 nd -1 branch line  622   a.  The 2 nd -2 branch line  622   b  may be disposed between the first main line  611  and the 1 st -4 branch line  612   d.  The 2 nd -2 branch line  622   b  may be disposed to be spaced apart from the first main line  611  and the 1 st -4 branch line  612   d.    
     A 2 nd -3 branch line  622   c  may have a shape extending in a direction from one point of the 2 nd -1 branch line  622   a  to one side of the 2 nd -1 branch line  622   a.  The 2 nd -3 branch line  622   c  may be disposed between a second main line  621  of second conductive line  620  and the 2 nd -2 branch line  622   b.  The 2 nd -3 branch line  622   c  may be disposed to be spaced apart from the second main line  621  and the 2 nd -2 branch line  622   b.  The 2 nd -3 branch line  622   c  may be disposed between the 1 st -3 branch line  612   c  and the 1 st -4 branch line  612   d.  The 2 nd -3 branch line  622   c  may be disposed to be spaced apart from the 1 st -3 branch line  612   c  and the 1 st -4 branch line  612   d.    
     A 2 nd -4 branch line  622   d  may have a shape extending in a direction from another point of the 2 nd -1 branch line  622   a  to one side of the 2 nd -1 branch line  622   a.  The 2 nd -4 branch line  622   d  may be disposed between the second main line  621  and the 2 nd -3 branch line  622   c.  The 2 nd -4 branch line  622   d  may be disposed to be spaced apart from the second main line  621  and the 2 nd -3 branch line  622   c.  The 2 nd -4 branch line  622   d  may be disposed between the 1 st -2 branch line  612   b  and the 1 st -3 branch line  612   c.  The 2 nd -4 branch line  622   d  may be disposed to be spaced apart from the 1 st -2 branch line  612   b  and the 1 st -3 branch line  612   c.    
     The second subregion of the horizontal pattern design  600  may have an identical or similar structure to the first subregion. For example, a structure of 1 st -6 to 1 st -9 branch lines  612   f  to  612   i  of the second subregion may be identical or similar to the structure of the 1 st -1 to 1 st -4 branch lines  612   a  to  612   d  of the first subregion. A structure of 2 nd -6 to 2 nd -9 branch lines  622   f  to  622   i  of the second subregion may be identical or similar to the structure of the 2 nd -1 to 2 nd -4 branch lines  622   a  to  622   d  of the first subregion. 
     The third subregion of the horizontal pattern design  600  may have an identical or similar structure to the second subregion. For example, a structure of 1 st -11 to 1 st -14 branch lines  612   k  to  612   n  of the third subregion may be identical or similar to the structure of the 1 st -6 to 1 st -9 branch lines  612   f  to  612   i  of the second subregion. A structure of 2 nd -11 to 2 nd -14 branch lines  622   k  to  622   n  of the third subregion may be identical or similar to the structure of the 2 nd -6 to 2 nd -9 branch lines  622   f  to  622   i  of the second subregion. 
     A third conductive line  630  may include a third main line  631  that may have a snaked shape extending in a serpentine manner along a separation space between the first main line  611 , the second main line  621 , and the plurality of branch lines  612   a  to  612   n  and  622   a  to  622   n.  The 3 rd -1 sub-pad  634   a  and the 3 rd -2 sub-pad  634   b  are disposed on third main line  631 . Also, the ground  535  may be formed at a second end portion of the third conductive line  630 . 
       FIGS. 7A to 7C  illustrate conceptual diagrams showing voltage contrast images of a main pad of a pattern design according to embodiments of the inventive concepts according to a state. 
     Voltage contrast inspection (VCI) technology is inspection technology for detecting defects included in electronic circuits. For example, in the VCI technology, inspection may be performed on a pattern design implemented in a test chip using charged particles such as an electron beam or an ion beam for example. In the VCI technology, it is possible to obtain a voltage contrast image for a pattern design. In the VCI technology, it is possible to inspect defects in the pattern design by comparing a voltage contrast image in a normal state with the obtained voltage contrast image of the pattern design. For example, defect inspection may be performed on the pattern design using a defect inspection apparatus to which the VCI technology is applied. The defect inspection apparatus may be referred to as an electron beam inspection apparatus. 
     For example, the electron beam inspection apparatus may scan a pattern design using an electron beam. The electron beam inspection apparatus may classify a portion of a pattern design in which a voltage contrast image that appears is different from a reference voltage contrast image of the portion of the pattern design as a defect on the voltage contrast image according to a scan result. The electron beam inspection apparatus may determine a position and type of the defect of the pattern design using the defect on the voltage contrast image. 
     For example, the electron beam inspection apparatus may include a scanner, a display, a user interface, a memory, and a controller. 
     For example, the scanner may scan a main pad region formed in a first end portion of the pattern design using a particle beam. The controller may determine main pad information on the basis of a scan result for the main pad region. The scanner may scan a first sub-pad region formed in a first end portion of a first subregion of the pattern design using the particle beam. The controller may generate first sub-pad information on the basis of a scan result for the first sub-pad region. 
     The main pad information may indicate whether there is a defect in an entirety of the pattern design. The first sub-pad information may indicate whether there is a defect in the first subregion positioned between the first end portion and the second end portion of the pattern design. 
     The main pad information may indicate that the pattern design is in a normal state when a main voltage contrast image detected from the main pad region using the particle beam is the same as the reference voltage contrast image. 
     The main pad information may indicate that the pattern design is in a defective state when the main voltage contrast image detected from the main pad region using the particle beam is different from the reference voltage contrast image. 
     The first sub-pad information may indicate that the first subregion is in a normal state when the main voltage contrast image detected from the main pad region using the particle beam is the same as a first sub voltage contrast image detected from the first sub-pad region using the particle beam. As will be understood from the description hereinafter, 
     The first sub-pad information may indicate that the first subregion is in a defective state when the main voltage contrast image detected from the main pad region using the particle beam is different from the first sub voltage contrast image detected from the first sub-pad region using the particle beam. 
     The display may display scan results. The user interface may include an interface for a user of the electron beam inspection apparatus. The memory may store various types of commands and programs which are used in the electron beam inspection apparatus. The controller may perform an overall control operation on the electron beam inspection apparatus. 
       FIG. 7A  illustrates a conceptual diagram showing voltage contrast images when pattern designs are in a normal state. 
     Referring to  FIG. 7A , the electron beam inspection apparatus may scan main pads of the pattern designs and display voltage contrast images  710  and  720 . The main pads may be identical or similar to the main pads  513 ,  523 , and  533  of  FIG. 5  or the main pads  613 ,  623 , and  633  of  FIG. 6 . For example, the first, second and third main pad images  711 ,  712  and  713  of the voltage contrast image  710  may correspond respectively to images of main pads  513 ,  523 , and  533  of  FIG. 5  or the main pads  613 ,  623 , and  633  of  FIG. 6 . For example, the first, second and third main pad images  721 ,  722  and  723  of the second contrast image  720  may correspond respectively to images of main pads  513 ,  523 , and  533  of  FIG. 5  or the main pads  613 ,  623 , and  633  of  FIG. 6 . Each of the main pads may have a structure in the form of a lattice or a matrix, and may be characterized as having a conductive line of a lattice-type pattern. 
     The electron beam inspection apparatus may determine whether there is a defect in the pattern designs using the contrast of the voltage contrast images  710  and  720  of the pattern design. For example, when a first pattern design is in a normal state, a first main pad image  711  and a second main pad image  712  of the voltage contrast image  710  of the first pattern design may be displayed as dark images (as indicated by dashed lines). When the first pattern design is in a normal state, a third main pad image  713  may be displayed as a bright image (as indicated with cross-hatched lines). 
     When a second pattern design is in a normal state, the voltage contrast image  720  of the second pattern design may be the same as the voltage contrast image  710  of the first pattern design. For example, when the second pattern design is in a normal state, a first main pad image  721  and a second main pad image  722  of the second pattern design may be displayed as dark images in the same manner as the first main pad image  711  and the second main pad image  712  of the first pattern design. When the second pattern design is in a normal state, a third main pad image  723  of the second pattern design may be displayed as a bright image in the same manner as the third main pad image  713  of the first pattern design. 
       FIG. 7B  illustrates a conceptual diagram showing voltage contrast images when a defect occurs in a third conductive line of the second pattern design. 
     Referring to  FIG. 7B , when the second pattern design is in a defective state, the voltage contrast image  720  of the second pattern design may be different from the voltage contrast image  710  of the first pattern design. For example, when the third conductive line of the second pattern design is opened, the third main pad image  723  may be displayed as a dark image differently from the third main pad image  713  of the first pattern design. 
       FIG. 7C  is a conceptual diagram showing voltage contrast images when a defect occurs in a second conductive line of the second pattern design. 
     Referring to  FIG. 7C , when the second conductive line of the second pattern design is short-circuited, the second main pad image  722  may be displayed as a bright image differently from the second main pad image  712  of the first pattern design. 
     The electron beam inspection apparatus may inspect first sub-pads of the second pattern design when it is determined that there is a defect in the second pattern design. Voltage contrast images of the first sub-pads may be displayed as shown in  FIGS. 8A to 8C  below. 
       FIGS. 8A to 8C  illustrate conceptual diagrams showing voltage contrast images of sub-pads of a pattern design according to embodiments of the inventive concepts according to a state thereof. 
       FIG. 8A  is a conceptual diagram showing voltage contrast images of first sub-pads when a first subregion is in a normal state (such as described with respect to  FIG. 7A  for example). The first subregion may be identical or similar to the first subregion of  FIG. 5 . The first subregion may be identical or similar to the first subregion of  FIG. 6 . The first sub-pads may be identical or similar to the 1 st -1, 2 nd -1, and 3 rd -1 sub-pads  514   a,    524   a,  and  534   a  of  FIG. 5 . The first sub-pads may be identical or similar to the 1 st -1, 2 nd -1, and 3 rd -1 sub-pads  614   a,    624   a,  and  634   a  of  FIG. 6 . The first, second and third conductive lines as described may respectively correspond to the first, second and third conductive lines  510 ,  520  and  530  of  FIG. 5 , or the first, second and third conductive lines  610 ,  620  and  630  of  FIG. 6 . 
     Referring to  FIG. 8A , the electron beam inspection apparatus may scan first sub-pads of a second pattern design and display a voltage contrast image  800 . 
     For example, when the first subregion is in a normal state, an image  810  of a first conductive line and a 1 st -1 sub-pad image  811   a  may be dark images (as indicated by dashed lines). When the first subregion is in a normal state, an image  820  of a second conductive line and a 1 st -2 sub-pad image  821   a  may be dark images (as indicated by dashed lines). When the first subregion is in a normal state, an image  830  of a third conductive line and a 1 st -3 sub-pad image  831   a  may be bright images (as indicated with cross-hatched lines). 
     When it is determined that the first subregion is in a normal state, the electron beam inspection apparatus may inspect second sub-pads in order to determine whether there is a defect in a second subregion. For example, voltage contrast images of the second sub-pads may be displayed as shown in  FIGS. 8B or 8C  below. 
       FIG. 8B  illustrates a conceptual diagram showing voltage contrast images of second sub-pads when a third conductive line of the second subregion is in a defective state (such as described with respect to  FIG. 7B  for example). The second subregion may be identical or similar to the second subregion of  FIG. 5 . The second subregion may be identical or similar to the second subregion of  FIG. 6 . The second sub-pads may be identical or similar to the 1 st -2, 2 nd -2, and 3 rd -2 sub-pads  514   b,    524   b,  and  534   b  of  FIG. 5 . The second sub-pads may be identical or similar to 1 st -2, 2 nd -2, and 3 rd -2 sub-pads  614   b,    624   b,  and  634   b  of  FIG. 6 . 
     Referring to  FIG. 8B , the electron beam inspection apparatus may scan the second sub-pads of the second pattern design and display a voltage contrast image  800 . 
     For example, when the third conductive line of the second subregion is in a defective state, an image  830  of the third conductive line of the second subregion and a 2 nd -3 sub-pad image  831   b  may be different from the image  830  of the third conductive line of the first subregion and the 1 st -3 sub-pad image  831   a  of  FIG. 8A . For example, the image  830  of the third conductive line of the second subregion and the 2 nd -3 sub-pad image  831   b  may be dark images. In this case as described with respect to  FIG. 8B , as the first and second conductive lines are assumed to not be in a defective state, an image  810  of a first conductive line and a 2 nd -1 sub-pad image  811   b  may be dark images, and an image  820  of a second conductive line and a 2 nd -2 sub-pad image  821   b  may be dark images. 
       FIG. 8C  illustrates a conceptual diagram showing voltage contrast images of the second sub-pads when a second conductive line of the second subregion is in a defective state (such as described with respect to  FIG. 7C  for example). Referring to  FIG. 8C , when the second conductive line of the second subregion is in a defective state, an image  820  of the second conductive line of the second subregion and a 2 nd -2 sub-pad image  821   b  may be different from the image  820  of the second conductive line of the first subregion and the 1 st -2 sub-pad image  821   a  of  FIG. 8A . For example, the image  820  and the 2 nd -2 sub-pad image  821   b  of the second conductive line of the second subregion may be bright images. In this case as described with respect to  FIG. 8C , as the first and third conductive lines are assumed to not be in a defective state, an image  810  of a first conductive line and a 2 nd -1 sub-pad image  811   b  may be dark images, and an image  830  of a third conductive line and a 2 nd -3 sub-pad image  831   b  may be bright images. 
     The electron beam inspection apparatus may scan the second subregion using an electron beam when it is determined that the second subregion is in a defective state. For example, the voltage contrast images of the second subregion may be displayed as shown in  FIGS. 9A to 9C  below. 
       FIGS. 9A to 9C  illustrate conceptual diagrams showing voltage contrast images of conductive lines of a pattern design according to embodiments of the inventive concepts according to a state. 
       FIG. 9A  illustrates a conceptual diagram showing voltage contrast images of a second subregion when the second subregion is in a normal state (such as described with respect to  FIG. 7A  for example). The second subregion may be identical or similar to the second subregion of  FIG. 5 . The second subregion may be identical or similar to the second subregion of  FIG. 6 . 
     Referring to  FIG. 9A , the electron beam inspection apparatus may scan the second subregion and display a voltage contrast image  900 . 
     For example, when the second subregion is in a normal state, an image  910  of a first conductive line and an image  920  of a second conductive line may be dark images (as indicated by dashed lines). When the second subregion is in a normal state, an image  930  of a third conductive line may be a bright image (as indicated with cross-hatched lines). The first, second and third conductive lines as described may respectively correspond to the first, second and third conductive lines  510 ,  520  and  530  of  FIG. 5 , or the first, second and third conductive lines  610 ,  620  and  630  of  FIG. 6 . 
       FIG. 9B  illustrates a conceptual diagram showing voltage contrast images of the second subregion when the third conductive line of the second subregion is in a defective state. When the third conductive line of the second subregion is opened, an image  930   a  of a first region of the third conductive line is a dark image (not a bright image as it would be if in a normal state) because of an open portion  931 . That is, when the third conductive line of the second subregion is opened because of open portion  931 , an image  930   a  of the first region of the third conductive line is a dark image and an image  930   b  of a second region of the third conductive line is a bright image like an image in a normal state. The electron beam inspection apparatus may detect the open portion  931  of the third conductive line using the image  930   a  of the first region and the image  930   b  of the second region. 
       FIG. 9C  illustrates a conceptual diagram showing voltage contrast images of the second subregion when the second conductive line and the third conductive line of the second subregion are short-circuited. When the second conductive line and the third conductive line of the second subregion are short-circuited, the image  920  of the second conductive line is a bright image (not a dark image as it would be if in a normal state). That is, when the second conductive line and the third conductive line of the second subregion are short-circuited because of short-circuited portion  921 , an image of a short-circuited portion  921  is a dark image. The electron beam inspection apparatus may detect the short-circuited portion  921  using the image  920  of the second conductive line and the image  930  of the third conductive line. 
       FIG. 10  illustrates an electron beam inspection apparatus according to embodiments of the inventive concepts. 
     Referring to  FIG. 10 , electron beam inspection apparatus  10  may include scanner  1010 , controller  1020 , memory  1030 , user interface  1040 , and display  1050 . Scanner  1010  may scan pattern design  1070  using particle beam  1060  under control of controller  1020 . Controller  1020  may for example generate main pad information responsive to scanning a main pad region of pattern design  1070  which may be configured such as shown in  FIG. 5 , and may also for example generate first sub-pad information responsive to scanning a first sub-pad region of pattern design  1070  which may be configured as shown in  FIG. 5 . Controller  1020  may determine a state of the pattern design  1070  based on the main pad information and the first sub-pad information. Controller  1020  may be a device which includes one or more processor cores such as for example a general-purpose CPU, a dedicated application specific integrated circuit (ASIC), or an application processor. 
     Memory  1030  may store data used to operate electron beam inspection apparatus  10 . For example, memory  1030  may include volatile/nonvolatile memory and may store processed data, results or data to be processed. The user interface  1040  may include for example at least one input device such as for example a keypad, a touch screen, or the like for the purpose of enabling user input into the electron beam inspection apparatus  10 . Controller  1020  may for example display information related to the main pad information, the first sub-pad information and the state of the pattern design  1070  on display  1050 . The electron beam inspection apparatus  10  may include additional circuits and components. 
       FIG. 11  illustrates a flow chart of a defect inspection method for pattern design according to embodiments of the inventive concepts. The defect inspection method may for example be performed by electron beam inspection apparatus  10  as described with respect to  FIG. 10  on a pattern design such as shown and described with respect to  FIG. 5 . 
     Referring to  FIG. 11 , in operation S 1110 , controller  1020  may control scanner  1010  to scan a main pad region formed at a first end portion of a pattern design such as pattern design  500  shown in  FIG. 5  using particle beam  1060  and generate main pad information. In operation S 1120 , controller  1020  may control scanner  1010  to scan a first sub-pad region formed at a first end portion of a first subregion of the pattern design such as pattern design  500  shown in  FIG. 5  using particle beam  1060  and generate first sub-pad information. In operation S 1130 , controller  1020  may determine a state of the pattern design such as pattern design  500  shown in  FIG. 5  based on the main pad information and the first sub-pad information. As should be understood as previously described, electron beam inspection apparatus  10  may classify a portion of a pattern design in which a voltage contrast image that appears is different from a reference voltage contrast image of the portion of the pattern design as a defect on the voltage contrast image according to a scan result. The electron beam inspection apparatus may determine a position and type of the defect of the pattern design using the defect on the voltage contrast image. 
     According to the inventive concepts, by using the pattern design and the method for inspecting the pattern design, it is possible to significantly reduce time for inspecting defects in a circuit to which a pattern design is applied. 
     As will be appreciated by those skilled in the art, the inventive concepts may be modified and varied over a wide range of applications. Therefore, the scope of the inventive concepts should not be limited to any of the specific exemplary teachings discussed above but may be defined by the following claims.