Patent Document

BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a semiconductor device. In particular, it relates to an array configuration of a group of bump electrodes for external connection on a flip-chip LSI (hereafter referred to as a FCLSI) having a group of bump electrodes for external connection on the surface of a semiconductor chip, or an array structure of a group of external connection terminals of a ball grid array LSI (hereafter referred to as a BGA) comprising a group of bump-shaped external connection terminals on one surface of a package.  
           [0003]    2. Description of the Prior Art  
           [0004]    As the scale and density of LSI increases, conventional systems configured with a plurality of LSI devices may now be integrated on one semiconductor chip. Specifically, in LSI used for communication systems, since signal processing of a plurality of channels on one chip has become possible, the number of signal lines drawn out of one chip, that is, the number of electrodes for external connection can be increased dramatically. Meanwhile, further miniaturization is required for LSI applied to mobile equipment, such as personal handy phones, thus the FCLSI or BGA is proposed, where the external connect terminals are arrayed two-dimensionally in order to achieve, multiple terminals and miniaturization, and the terminal array pitch is narrowed, as well as ingenuity has effected the layout method, this is accompanied by a further increase of the number of terminals.  
           [0005]    For example, in Japanese Patent Application Laid-Open No. Hei 5-62978 (hereafter referred to as the well-known example), a flip chip, wherein layout density is increased while maintaining distance between bumps by arranging the bumps in a staggered pattern with the same pitch throughout, is mentioned.  
           [0006]    However, in the conventional FCLSI and BGA, for example, since a simple grid array or a staggered grid array such as that in the well-known example is adopted for all external connect terminals, although LSI may be accomplished, a new problem for mounting the LSI in practical use occurs when the array pitch becomes narrow. In other words, when the LSI where the external connect terminals are arrayed two-dimensionally, either in a simple grid array or a staggered grid array, on a printed wiring board (hereafter referred to as PWB), it becomes difficult to connect to the signal terminals at any distance more than two rows away from the outermost periphery. FIG. 20 is a diagram for illustrating this problem; FIG. 20A is a typical plane view of a PWB  930  mounting surface, on which electronic components including the conventional LSI  900  are mounted; and FIG. 20B is a typical plane view of the enlarged P section shown in FIG. 20A. For example, in FCLSI or BGA with the narrowest bump array pitch, the number of wires capable of passing through the connection electrodes corresponding to each external connect terminal of the LSI formed on a PWB used for mounting, is limited (normally to one). Consequently, when the number of wires capable of passing through the connection electrodes is, for example, one as shown in FIG. 20, all feeder wires  935  for regions outside the LSI mounting section  900 P, can be formed with one wiring layer for the connection electrodes  957 , which connect the signal terminals accommodated within the region containing the two rows adjacent to the outermost periphery, however, in order to draw the signal terminals out of an LSI area containing more than two rows inside of the outermost periphery, for that reason alone, it is necessary to make the PWB multi-layered, thereby leading to increased PWB costs.  
           [0007]    In addition, it is common for FCLSI to have arranged in it an input/output buffer circuitry (hereafter referred to as I/O circuitry) for giving and receiving signals to and from the external connect terminals along the edge of the chip and to rewire the spaces between the I/O circuitry and the external connect terminals on the chip. However, since the wiring on the chip has cross sectional area that is significantly smaller than that of the wiring on the PWB on which the chip is mounted, there are problems such as a voltage drop occurring due to the wiring between the I/O circuitry and the power supply terminal, which supplies power to the circuitry, and the size of voltage drop becomes larger in proportion to the wiring length.  
         BRIEF SUMMARY OF THE INVENTION  
       OBJECTIVES OF THE INVENTION  
         [0008]    The objective of the present invention is to provide LSI having external connect terminals, such as bump electrodes, which are arrayed two-dimensionally on the same surface; wherein the LSI comprises a layout of external connect terminals capable of easily accommodating the feeder interconnects drawn out of the LSI mounting area from signal connection electrodes, which connect the external connect signal terminals of the LSI, with a single wiring layer in the PWB on which the LSI is mounted, even if the number of signal terminals are increased.  
         SUMMARY OF THE INVENTION  
         [0009]    A semiconductor device of the present invention comprises a plurality of bump electrodes for external connection arrayed two-dimensionally on the surface of a rectangular- or square-shaped semiconductor chip where the desired elements and wirings are formed; wherein when directions of two edges of the chip orthogonal to each other are specified as X and Y directions, all of the bump electrodes are arranged at either of the grid points determined with a distance Sx1 between grids in the X direction and a distance Sy1 between grids in the Y direction, and the bump electrodes include a first group of bump electrodes, a second group of bump electrodes arrayed at the outer periphery of the first group of bump electrodes, and a third group of bump electrodes arrayed at the outer periphery of the second group of bump electrodes, wherein the first group of bump electrodes and the second group of bump electrodes are arrayed like a grid with an array interval distance Sx1 in the X direction and an array interval distance Sy1 in the Y direction, and the third group of bump electrodes has a structure satisfying Sx2&gt;Sx1 and Sy2&gt;Sy1, when an array interval distance in the X direction of the third group of bump electrodes arranged in the first area, which is enclosed by edges, which are parallel to a diagonal line of the chip and the X direction, is specified as Sx2, and an array interval distance in the Y direction of the third group of bump electrodes arranged in the second area, which is enclosed by edges, which are parallel to a diagonal line of the chip and the Y direction, is specified as Sy2. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    The above-mentioned and other objects, features and advantages of this invention will become more apparent by reference to the following detailed description of the invention taken in conjunction with the accompanying drawings, wherein:  
         [0011]    [0011]FIG. 1 is a diagram, which describes the first embodiment of the LSI of the present invention, and is a typical plane view illustrating a layout of bump electrodes for external connection;  
         [0012]    [0012]FIGS. 2A, 2B, and  2 C are typical cross sectional views illustrating cross sections cut along the lines A 1 -A 1 ′, A 2 -A 2 ′, and A 3 -A 3 ′ shown in FIG. 1;  
         [0013]    [0013]FIG. 3 is a typical plane view illustrating an outline of the chip structure of LSI most suitable for this embodiment;  
         [0014]    [0014]FIG. 4 is a plane view for describing the definitions of a chip such as edge of the chip, direction of the edge, and regions;  
         [0015]    [0015]FIG. 5 is a diagram describing the PWB; FIG. 5A is a typical plane view of the PWB on which various electronic components including the LSI are mounted; and FIG. 5B is a typical cross-sectional view cut along the line Z 1 -Z 1 ′ shown in FIG. 5A;  
         [0016]    [0016]FIG. 6 is an enlarged typical plane view of the section corresponding to the Q section shown in FIG. 5A;  
         [0017]    [0017]FIG. 7 is an enlarged plane view of the section corresponding to the R section shown in FIG. 5A;  
         [0018]    [0018]FIG. 8 is a typical plane view illustrating a layout of bump electrodes for external connection in the LSI of the modified example of the first embodiment;  
         [0019]    [0019]FIG. 9 is an enlarged plane view of the section corresponding to the Q section shown in FIG. 5A;  
         [0020]    [0020]FIG. 10 is an enlarged plane view of the section corresponding to the R section shown in FIG. 5A;  
         [0021]    [0021]FIG. 11 is a typical plane view illustrating a outline of the chip structure in the LSI of the second embodiment of the present invention;  
         [0022]    [0022]FIG. 12 is a diagram, which describes the LSI of the second embodiment of the present invention, and is a typical plane view illustrating the layout of bump electrodes for external connection;  
         [0023]    [0023]FIGS. 13A, 13B, and 13 Carecross-sectionalviewstypically illustrating the cross sections respectively cut along lines C 1 -C 1 ′, C 2 -C 2 ′, and C 3 -C 3 ′ shown in FIG. 12;  
         [0024]    [0024]FIG. 14 is an enlarged typical plane view of the section corresponding to the R section shown in FIG. 5A;  
         [0025]    [0025]FIG. 15 is a diagram, which describes the LSI of the modified example of the second embodiment, and is a typical plane view illustrating the layout of bump electrodes for external connection;  
         [0026]    [0026]FIGS. 16A, 16B, and  16 C are typical cross-sectional views respectively illustrating the cross-sections cut along lines D 1 -D 1 ′, D 2 -D 2 ′, and D 3 -D 3 ′ shown in FIG. 15;  
         [0027]    [0027]FIG. 17 is a diagram, which describes an example of the PWB on which the LSI of the modified example of the second embodiment is mounted; FIG. 17A is a typical outline plane view of the surface on which the components are mounted; FIG. 17B is a cross sectional view illustrating the outline cross section along the line Z 2 -Z 2 ′ shown in FIG. 17A when the LSI  4  is mounted; and FIG. 17C is an enlarged typical plane view of the H section shown in FIG. 17A;  
         [0028]    [0028]FIG. 18 is a typical cross sectional view of an example of a BGA;  
         [0029]    [0029]FIG. 19 is a plane view illustrating an example of a method for arranging the first group of bump electrodes; and  
         [0030]    [0030]FIG. 20A is a typical plane view of a conventional PWB mounting surface on which electronic components including LSI are mounted; and FIG. 20B is an enlarged typical plane view of the P section shown in FIG. 20A. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0031]    Next, the present invention is described with reference to the drawings.  
         [0032]    First, in order to make the following description easier to understand, definitions such as the edge of the chip, direction of the edge, and the area, which are commonly used in the following description of each embodiment, are described with reference to FIG. 4. Diagonal lines  121  and  123 , a first boundary line  161 , a second boundary line  163 , a third boundary line  165 , and an edge boundary line  171  are provided on the surface of a chip  100  as virtual lines. In addition, the second boundary line  163  falls in the outer periphery of the first boundary line  161 ; the third boundary line  165  falls in the outer periphery of the second boundary line  163 ; and the edge boundary line  171  falls in the outer periphery of the third boundary line  165 . The edge boundary line  171  is substantially parallel with the edge section of the chip  100 . In addition, the area enclosed by the first edge  111 , which is an edge in the X direction, and the diagonal lines  121  and  123 , and the area enclosed by the first edge  112  and diagonal lines  121  and  123  are regarded as the first areas  131  and  133 , respectively; whereas the area enclosed by the second edge  116 , which is an edge in the Y direction, and diagonal lines  121  and  123 , and the area enclosed by the second edge  117  and diagonal lines  121  and  123  are regarded as the second areas  141  and  143 , respectively.  
         [0033]    Next, the first embodiment of the present invention is described.  
         [0034]    Referencing FIGS. 1, 2, and  3 , the LSI  1  of this embodiment comprises internal circuitry  80 , which performs the desired functions, and I/O circuitries  85 , which input/output signals to/from the external connect terminals within the chip  100 ; wherein the I/O circuitries  85  are arranged so as to substantially enclose the internal circuitry  80 . In addition, the I/O circuitries  85  comprise a plurality of input/output buffer cells  82  (hereafter referred to as I/O cells). It should be noted that the I/O circuitries  85  of the chip  100  are arranged proximate to the center of the chip  100  by spacing from the edge boundary line  171 ; and the chip  100  includes peripheral area  88  where, for example, bonding pads (not shown in the Figure), can be arranged between the I/O circuitries  85  and the edge boundary line  171 , if necessary.  
         [0035]    The chip  100 , on which the desired elements and wirings are formed, comprises external connect terminals (not shown in the Figure), which are arranged two-dimensionally via an insulating film  110 , such as a polyimide resin, on the surface, (on the surface where the elements and wiring are formed), and includes the bump electrodes  160  for external connection, such as solder balls, on the external connect terminals. It should be noted that each terminal where a bump electrode  160  is mounted is connected to a corresponding electrode having an I/O cell  82  of the chip  100  by means of the rearrangement wiring; however, graphic representation is omitted since it is not directly related to the structure of the present invention.  
         [0036]    To begin with, an outline of the layout structure of the bump electrodes  160  is described. The bump electrodes  160  of the LSI  1  of this embodiment are arranged at any of the grid points of the virtual matrix grid, which are specified by the distance Sx1 between grids in the X direction and the distance Sy1 between grids in the Y direction on the entire surface of the chip  100 , and include a first group of bump electrodes  162  arranged at the center of the chip  100 ; a second group of bump electrodes  164  arranged in the outer periphery of the first group of bump electrodes  162 ; and a third group of bump electrodes  166  arranged in the outer periphery of the second group of bump electrodes  164 . More specifically, for example, the first group of bump electrodes  162  is arranged within the area enclosed by the first boundary line  161 ; the second group of bump electrodes  164  is arranged within a circular area between the first boundary line  161  and second boundary line  163 ; and the third group of bump electrodes  166  is arranged within a circular area between the second boundary line  163  and the edge boundary line  171 . In addition, the first group of bump electrodes  162  and second group of bump electrodes  164  are arrayed on the entire surface of the layout area like a matrix with the array interval distance Sx1 in the X direction and array interval distance Sy1 in the Y direction. The third group of bump electrodes  166  is arrayed like a matrix with the array interval distance Sx2 in the X direction and array interval distance Sy1 in the Y direction, for example, in the first areas  131  and  133 ; whereas it is arrayed with the array interval distance Sx1 in the X direction and array interval distance Sy2 in the Y direction like a matrix in the second areas  141  and  143 . It should be noted that Sx2=2×Sx1 and Sy2=2×Sy1 in this embodiment.  
         [0037]    Next, an outline of the functions of each group of bump electrodes is described. The first group of bump electrodes  162  is constructed by arranging the first bump electrodes  151 V for power supply, which supply the high-potential power, and the first bump electrodes  151 G for power supply, which supply the low-potential power, alternately, in order to make the internal circuitry  80  in the LSI  1  operate. The second group of bump electrodes  164  is constructed by arranging the second power supply bump electrodes  153 V, which supply high-potential power, and the second power supply bump electrodes  153 G, which supply low-potential power, in a single line in the innermost perimeter line, alternately, in order to make the I/O circuitries  85  in the LSI  1  operate; as well as by arranging the signal bump electrodes  157 , which input/output the signals to/from the chip  100 , in the outer periphery of the second power supply bump electrodes  153 V and  153 G. Moreover, a third group of bump electrodes  166  is constructed by arranging only the signal bump electrodes  157 , which input/output the signals from the LSI  1 .  
         [0038]    Next, the PWB on which the LSI  1  is mounted is described while referencing FIGS. 5 and 6. When the LSI  1  is mounted on the PWB  30 , the connection electrodes  32 , which are formed on the LSI mounting section  100   p , comprise first power supply connection electrodes  251 V and  251 G; second power supply connection electrodes  253 V and  253 G; and connection electrodes  257 , which correspond to the first power supply bump electrodes  151 V and  151 G; the second power supply bump electrodes  153 V and  153 G; and the signal bump electrodes  157  of the LSI  1 , respectively. It should be noted that power is supplied from different wiring layers, and that the first connection electrodes  251 V and  251 G for power supply and the second connection electrodes  253 V and  253 G for power supply are connected to corresponding wiring layers (not shown in the Figure) via the through holes  37  in the PWB  30 . In addition, it goes without saying that the layout intervals of each of these connection electrodes are the same as those of each of the corresponding bump electrodes. It should be noted that in order to simplify the following description, a first PWB-side virtual boundary line  161   p , a second PWB-side virtual boundary line  163   p , and a PWB-side virtual edge boundary line  171   p  are provided at locations corresponding to the first virtual boundary line  161 , the second boundary line  163 , and edge boundary line  171 , which has been used for describing the layout of bump electrodes of the LSI  1 . In addition, in each area separated by diagonal lines and edge sections in the LSI mounting section  100   p , a direction, which is parallel to the edge section of the LSI mounting section  100   p , that is, the X direction in the first areas  131  and  133 , or the Y direction in the second areas  141  and  143  of the chip  100  may be regarded as the horizontal direction; whereas the direction, which travels from the edge section of the LSI mounting section  100   p  to the center, that is, the Y direction in the first areas  131  and  133 , or the X direction in the second areas  141  and  143  of the chip  100  may be regarded as the vertical direction.  
         [0039]    When the design criteria of the wiring patterns comprising the connection electrodes of the PWB  30  are specified as, for example:  
         [0040]    connection electrode diameter: 100 μm;  
         [0041]    feeder wire width: 30 μm;  
         [0042]    insulation interval between connection electrodes and wiring: 60 μm or wider; and  
         [0043]    insulation interval between wirings: 30 μm or wider,  
         [0044]    the number of wires capable of passing between connection electrodes is one in an area when the layout interval of the connection electrodes is 250 μm, but becomes five when 500 μm. Consequently, when layout intervals of each bump electrode of the LSI  1  are specified, for example, as Sx1=Sy1=250 μm and Sx2=Sy2=500 μm for the first two rows from the outermost perimeter in the area between the PWB side virtual edge boundary line  171   p  and the second PWB side virtual boundary line  163   p , the horizontal layout intervals are 500 μm and the vertical layout intervals are 250 μm. In addition, the layout intervals of the connection electrodes within the area enclosed by the second PWB side virtual boundary line  163   p  are 250 μm in both of the horizontal and vertical directions. Consequently, for the connection electrodes, which are arranged in the first two rows from the outermost periphery side within the area enclosed by the second PWB side virtual boundary line  163   p , the feeder wires  35 , which are drawn out of the LSI mounting section  100   p , may be provided with only one wiring layer in accordance with the design criteria of the wiring pattern as shown in FIG. 6. In other words, feeder wires  35  may be provided for all signal connection electrodes  257 , which connect the bump electrodes  157  for signals of the LSI  1  with only one wiring layer in accordance with the design criteria of the wiring pattern in the PWB  30 .  
         [0045]    Next, the increase of the number of signal terminals according to this embodiment is verified. However, it is assumed that the number of wires capable of passing through is one and five when the intervals of connection electrodes are S and  2 S, respectively. To begin with, after the connection electrodes have been arranged as with the conventional manner like a matrix with the number of wires capable of passing through an interval of S being one, and the first two rows from the outer most periphery being used as connection electrodes for signals, if number of connection electrodes of one row from the outermost periphery is given as m, then the number of signal connection electrodes that may be obtained by the conventional simple matrix layout, that is, the number of signal bump electrodes is (2m−8) Meanwhile with the layout shown in FIG. 1 of this embodiment, it becomes (3m−44). Accordingly, if m is more than 36, the number of signal terminals can be increased without changing the wiring criteria of the mounting substrate in accordance with the layouts of the bump electrodes of this embodiment.  
         [0046]    Moreover, in the example of this embodiment, since the horizontal layout intervals of the bump electrodes and corresponding connection electrodes of the PWB  30  in the first two rows from the outermost periphery are specified as 250 μm at the corners, feeder wires from the periphery side of the PWB  30  are not affected even if, for example, the connection electrodes  280  are added as shown in FIG. 7. It should be noted that FIG. 7 is an enlarged plane view of the section corresponding to the R section shown in FIG. 5A. Since the number of signal connection electrodes that can be used when this layout is adopted, that is, the number of signal bump electrodes is (3m−24), the number of signal terminals can be further increased without changing the wiring criteria of the mounting substrate when m is more than 16.  
         [0047]    Next, the modified example of this embodiment is described. FIG. 8 is a typical plane view illustrating the layout of the external connection bump electrodes of the LSI  2  of this modified example; and FIG. 9 is an typical enlarged plane view of the section that corresponds to the Q section shown in FIG. 5A, which illustrates the layout of the connection electrodes and feeder wires of the LSI mounting section when the LSI  2  is mounted on the PWB  30 . Moreover, FIG. 10 is an enlarged plane view of the section that corresponds to the R section shown in FIG. 5A when the number of bump electrodes at the corners of the LSI  2  is increased. In the LSI  2  of this modified example, the third group of bump electrodes  166  is arrayed within a circular area between the second boundary line  163  and the edge boundary line  171  like a staggered grid. In this case, the array interval distances in the X and Y directions are Sx2 and Sy1 in the first areas  131  and  133 , respectively; whereas the array interval distances in the X and Y directions are Sx1 and Sy2 in the second areas  141  and  143 , respectively. In addition, by arranging the feeder wires from the signal connection electrodes of the PWB  30  on which the LSI  2  with the third group of the bump electrodes  166  arrayed like a staggered grid is mounted, as shown in FIG. 8, the feeder wires  35  may be provided for all signal connection electrodes  257 , which connect the signal bump electrodes  157  of the LSI  2  with only one wiring layer in accordance with the design criteria of the wiring pattern of the PWB  30 , and thus the number of signal terminals may be increased. In addition, since the corners of this modified example are similar to those of this embodiment, if it is assumed that the layout intervals of the bump electrodes, the layout intervals of the corresponding connection electrodes of the PWB, and the number of wires capable of passing through the connection electrodes have the same numeric values as the above, then by adding the connection electrodes  280  to the first two rows from the outermost periphery, as shown in FIG. 10, the horizontal layout interval may be specified as 250 μm without affecting the feeder wires from the connection electrodes at the inner periphery side of the PWB, the number of signal connection electrodes that may be used in this case, and accordingly, the number of signal bump electrodes to be (3m−24), and the number of signal terminals may be further increased without having to change the wiring criteria of the mounting substrate when m is more than  16 .  
         [0048]    In addition, in the LSI on which the I/O circuitries  85  are positioned proximate to the center of the chip as shown in FIG. 3, since the second power supply bump electrodes  153 V and  153 G for energizing the I/O circuitries  85  can be arranged adjacent to the I/O circuitries  85 , there is an effect that it is possible to moderate the voltage drop due to the wirings, which connect the second power supply bump electrodes  153 V and  153 G to the I/O circuitries  85 .  
         [0049]    Next, the second embodiment of the present invention is described with-reference to FIGS. 11 through 13.  
         [0050]    The LSI  3  of this embodiment includes internal circuitry  80  implementing the desired functions and I/O circuitries  85  within the chip  102 , wherein the I/O circuitries  85  are arranged so as to substantially enclose the internal circuitry  80 , and the I/O circuitries  85  comprise a plurality of the I/O cells  82 . In the chip  102  of this embodiment, since the I/O circuitries  85  are arranged adjacent to the edge boundary line  171  but not on the peripheral area  88 , which is a dead space, between the I/O circuitries  85  and the edge boundary line  171 , the size of the internal circuitry  80  can be enlarged even if the chip size is the same as that of chip  100  of the first embodiment. However, there are some advantages to the dead space in the chip  100  such as the fact that the chip  100  may be used as a chip for wire bonding connection without modification by pre-fabricating the bonding pads in the peripheral area  88 .  
         [0051]    Next, omitting the description of portions that are similar to the first embodiment and use the same reference numerals, a bump electrode layout having a principal difference is described.  
         [0052]    The bump electrodes  160  of the LSI  3  of this embodiment are also arranged at any of the grid points of a virtual matrix grid, which are specified by the distance Sx1 between grids in the X direction and the distance Sy1 between grids in the Y direction on the entire surface of the chip  102 , and include a first group of bump electrodes  162  arranged at the center of a chip  102 ; a second group of bump electrodes  164  arranged at the outer periphery of the first group of bump electrodes  162 ; a third group of bump electrodes  166  arranged at the outer periphery of the second group of bump electrodes  164 ; and a fourth group of bump electrodes  168  arranged at the outer periphery of the third group of bump electrodes  166 . More specifically, the first group of bump electrodes  162  is arranged within a area enclosed by a first boundary line  161 ; the second group of bump electrodes  164  is arranged within a circular area between the first boundary line  161  and a second boundary line  163 ; the third group of bump electrodes  166  are arranged within a circular area between the second boundary line  163  and a third boundary line  165 ; and the fourth group of bump electrodes  168  is arranged within a circular area between the third boundary line  165  and an edge boundary line  171 . In addition, the first group of bump electrodes  162  and second group of bump electrodes  164  are arrayed like a matrix on the entire surface of the layout area with the array interval distance Sx1 in the X direction and array interval distance Sy1 in the Y direction. The third group of bump electrodes  166  is arranged, for example, in a single row with an array interval distance Sx2 in the X direction in the first areas  131  and  133 ; and arranged in a single row with an array interval distance Sy2 in the Y direction in the second areas  141  and  143 . The fourth group of bump electrodes  168  is arranged like a matrix with, for example, an array interval distance Sx2 in the X direction and an array interval distance Sy1 in the Y direction in the first areas  131  and  133 ; and arranged like a matrix with the array interval distance Sx1 in the X direction and the array interval distance Sy2 in the Y direction in the second areas  141  and  143 . It should be noted that Sx2=2×Sx1 and Sy2=2×Sy1 in this embodiment as well.  
         [0053]    Next, an outline of the functions of each group of bump electrodes is described. The first group of bump electrodes  162  is constructed by arranging first power supply bump electrodes  151 V and  151 G, which allow the internal circuitry  80  of the LSI  3  to operate, alternatingly, in this embodiment. The second group of bump electrodes  164  and third group of bump electrodes  166  are constructed by arranging only the signal bump electrodes  157 , which input/output the signal to/from the chip  102 . In the fourth group of bump electrodes  168 , second power supply bump electrodes  153 V and  153 G, which allow the I/O circuitries  85  of the LSI  3  to operate, are arranged, for example, in respective pairs in the Y direction in the first areas  131  and  133 ; arranged in respective pairs in the X direction in the second areas  141  and  143 .  
         [0054]    With the LSI  3  this embodiment, feeder wires for all of the signal connection electrodes  257  connecting the signal bump electrodes of the LSI  3 , which are provided on the inside of the second power source connection electrodes  253 V and  253 G that connect the second power source bump electrodes  153 V and  153 G, may be provided in only one layer while still following a standard PWB wiring pattern layout in a PWB whereupon an LSI  3  has been mounted having the voltage drop due to the wires that connect the second power supply bump electrodes  153 V and  153 G to the I/O circuitries  85  mitigated by arranging the second power supply bump electrodes  153  V and  153 G in the first two rows from the outermost periphery and widening the horizontal layout intervals relative to the chip  102  on which I/O circuitries  85  have been arranged adjacent to the edge boundary line  171 . FIG. 14 illustrates a typical plane view of an example of the feeder interconnect pattern for the PWB, wherein the section corresponding to the R section shown in FIG. 5A is enlarged. In FIG. 14, the signal connection electrodes  258  are connection electrodes that may be added in accordance with the characteristics of the corner.  
         [0055]    Upon verification of the increased number of signal connection electrodes, it was found that the number of signal bump electrodes that may be provided in the LSI  3  of this embodiment was (2.5m−64) when prerequisites of the first embodiment such as the intervals of connection electrodes and the number of wires capable of passing through were met. In contrast, if m is more than  48 , then more bump electrodes for signals may be provided on the LSI  3  of this embodiment since the number of signal bump electrodes is (2m−40) when the bump electrodes  157  for signals are provided in first two rows from the inner periphery side of the second power supply bump electrodes  153 V and  153 G.  
         [0056]    Next, a modified example of the second embodiment is described with reference to FIGS. 15 and 16.  
         [0057]    This modified example has a structure suitable for the case where the PWB on which the LSI is mounted comprises conductive patterns, such as metals, which are connected to at least the entire surface of the peripheral area of the LSI mounting area, for example on the low-potential side (normally, ground potential) of the power source, in order to provide maximum restraint of the affects of electromagnetic noise from the outside.  
         [0058]    Referencing FIGS. 15 and 16, the LSI  4  of this modified example also comprises the chip  102  with the same structure as that of the second embodiment. Since only the layout method of the fourth group of bump electrodes  168  of the LSI  4  of this modified example differs from the LSI  3  of the second embodiment, this section will mainly describe the layout method. The fourth group of bump electrodes  168  in this modified example is arranged in a single row with an array interval distance Sx1 in the X direction in the first areas  131  and  133 , and arranged in a single row with the array interval distance Sy1 in the Y direction in the second areas  141  and  143  within a circular area between the third boundary line  165  and edge boundary line  171 . In addition, the fourth group of bump electrodes  168  includes only the second power supply bump electrodes  153 V and  153 G, and arranges them alternatingly.  
         [0059]    Next, a PWB whereupon the LSI  4  is mounted is described while referencing FIG. 17.  
         [0060]    The PWB  40  comprises a metal film  41 , which includes, for example, copper on the entire surface excluding the component mounting areas on the sides of the component mounting surfaces, upon which various electronic components including the LSI  4 , for example, are mounted. In addition, the metal film  41 , for example, is connected to the low-potential side of the power source. Accordingly, as shown in FIG. 17C, the second power supply connection electrodes  2573 G, which are connected to the low-potential side of the power source, are directly connected to the metal film  41  on the surface of the PWB  40 . Normally, the metal film  41  and each connection electrode including the signal connection electrodes  42  are formed with the same wiring layers and same materials. With this PWB  40 , since all connection electrodes other than the connection electrodes  42  for signals are inter-connected via the different wiring layers, the feeder wires  45 , which are drawn out of the LSI mounting section  102   p  from the signal connection electrodes  42  for connecting each signal bump electrode  157  of the LSI  4 , are formed by using only one layer of the lower wiring layers  50 . In addition, the signal connection electrodes  42  are connected to the feeder wires  45  via the through holes  47 .  
         [0061]    Accordingly, since the feeder wires from the signal connection electrodes  257 , which connect the bump electrodes  157  for signals when the LSI  4  is mounted on the PWB  40 , are comprised of the wiring layers  50 , the wiring patterns of the wiring layers  50  are patterns that are substantially similar to those shown in FIG. 9 in relation to the modified example of the first embodiment; thus, all signal lines may be drawn.  
         [0062]    In addition, with the same prerequisites as the second embodiment, since the number of bump electrodes for signals, which can be provided on the LSI  4  of this modified example is (2.5m−44) and the number of bump electrodes for signals is (2m−24) when the bump electrodes  157  for signals are provided in the first two rows from the inner periphery side of the second bump electrodes  153 V and  153 G for power supply, more bump electrodes for signals can be provided for the LSI  4  of this embodiment when m is more than 40.  
         [0063]    As mentioned above, the LSI of the present invention provides results such as allowing the number of signal terminals to be increased since feeder lines, which connect the signal bump electrodes formed on the inner periphery and which run from the PWB signal connection electrodes to the outside of the LSI mounting region, may be provided in only one wiring layer in accordance with the design criteria of the wiring pattern of the PWB, on which the LSI is mounted, while mitigating the voltage drop due to the wires by arranging all bump electrodes at any of the grid points virtually created in minimum grid pitch (Sx1, Sy1) on the entire chip surface, arranging the second bump electrodes  153 V and  153 G for power supply, which supply the power to the I/O circuitries  85 , adjacent to the I/O circuitries  85  in accordance with the position of the I/O circuitries  85  within the chip, and shortening the wiring distance between the second bump electrodes for power supply and the I/O circuitry.  
         [0064]    It should be noted that the present invention is not limited to the description of the above embodiments, and naturally various modifications are possible within the scope of the major points thereof.  
         [0065]    For example, the above embodiment has been described, as an example of an FCLSI having bump electrodes arranged two-dimensionally on the chip surface; however, the embodiment may naturally be applied similarly to the external connect terminals of the BGA. More specifically, referencing the typical cross sectional view of an example of the BGA shown in FIG. 18, the first embodiment and its modified example may be applied without changes in relation to the bump electrodes  260 , which are the external connect terminals. It should be noted that the BGA  20  is an example where the chip  100  or the chip  102  is mounted on the mounting substrate  22 , additionally, but it is not limited to this: the chip may be mounted on the mounting substrate  22  facing up so as to be connected using wire bonding. In addition, in cases where the FCLSI is mounted on a mounting substrate  22 , the PWB in the description of the above embodiment can be used as the mounting substrate  22 .  
         [0066]    Furthermore, the first group of bump electrodes  162  is described using an example, where they is arranged on the entire surface of an area enclosed with the first boundary line  161 , however, for example, the layout method, which is shown in FIG. 19 as an example, may also be possible, wherein the bump electrodes at a part of the grid points are excluded as necessary.  
         [0067]    Furthermore, the above embodiments and the modified examples thereof can be mixed within the same chip if necessary.  
         [0068]    As described above, the LSI of the present invention may obtain results such as eased formation of feeder wires drawn out of the LSI mounting area in a single wiring layer in the PWB on which the LSI is mounted, in an LSI having external connection terminals such as bump electrodes, which are arranged two-dimensionally upon the same surface, even if the number of signal terminals are increased.  
         [0069]    In addition, in the FCLSI, there is also an effect whereby it is possible to moderate the voltage drop of the I/O circuitry due to the power source wiring regardless of the layout position of the I/O circuitry on the chip.  
         [0070]    Although the invention has been described with reference to specific embodiments, this description is not meant to be construed in a limiting sense. Various modified examples of the disclosed embodiments will become apparent to persons skilled in the art upon reference to the description of the invention. It is therefore contemplated that the appended claims will cover any modified examples or embodiments as fall within the true scope of the invention.

Technology Category: 5