Patent Document

BACKGROUND OF THE INVENTION 
     Field of the Invention 
     The invention relates to a memory configuration having a connection area and cell arrays that adjoin the connection area. The cell array has a matrix-like memory with row and column decoders that are each connected to address lines. 
     Semiconductor memories are typically built up from small, regular cell units (e.g., in the case of a 256 Mb DRAM, the cell units are 4 Mb). The cell units are combined into larger configurations (cell arrays) that, in the case of a 256 Mb DRAM, in turn often have a size of 64 Mb. In the case of the 256 Mb DRAM, it is, therefore, necessary for four of these cell arrays to be disposed on the module. It is often the case that two cell arrays are disposed beside each other in each case and a connection area is formed between two adjacently disposed cell arrays. The connection area has bonding pads that are connected to the switching elements of the cell arrays and are used for connecting further circuits. Because an individual cell array often has a side ratio of 2:1, and the connection area is relatively small, the result, for example, in the case of the 256 Mb DRAM having four cell arrays, is immediately an overall side ratio of 2:1. In the case of a 512 Mb DRAM, in which eight cell arrays (512 M=8*64 M) then have to be placed, two alternatives then remain in the prior art: 
     a) four cell arrays beside one another; or 
     b) in each case four cell arrays in a 2*2 configuration on both sides of the connection area. 
     Both configurations have an unfavorable side ratio of 4:1 (case(a)) or 1:1 (case(b)). Under certain circumstances, the side ratios lead to chip dimensions that no longer fit into standardized housings. 
     SUMMARY OF THE INVENTION 
     It is accordingly an object of the invention to provide a memory configuration with a central connection area that overcomes the herein afore-mentioned disadvantages of the heretofore-known devices of this general type and that provides memory arrays with a more flexible construction. 
     With the foregoing and other objects in view, there is provided, in accordance with the invention, a memory configuration including address lines, cell arrays having side edges, and a centrally disposed connection area having four side edges, including longitudinal sides, and connecting pads. The cell arrays adjoin the connection area, are disposed on each of the four side edges of the connection area in a closed ring around the connection area, each have a matrix-like memory with decoders each connected to at least one of the address lines, each have at least two side edges adjoining side edges of two other ones of the cell arrays, and each are subdivided in a longitudinal direction into a first cell subarray and a second cell subarray. The connecting pads are electrically connected to the cell arrays. Each of the first and second cell subarrays have longitudinal sides adjoining the connection area and another one of the cell arrays and a decoder disposed at right angles to one of the longitudinal sides adjoining one of the group consisting of the connection area and the another one of the cell arrays. Each of the cell arrays having two mutually adjoining decoders is disposed in a center of one of the longitudinal sides of the connection area. A first of the decoders is connected to first of the address lines disposed parallel to the longitudinal direction in the first cell subarray. A second of the decoders connected to second of the address lines disposed parallel to the longitudinal direction in the second cell subarray. 
     A significant advantage of the invention is that a centrally disposed connection area is provided, which is surrounded annularly by cell arrays. As such, a very compact configuration of a large number of cell arrays in one memory configuration is achieved. 
     In accordance with another feature of the invention, the decoders of each of the cell arrays include row decoders and column decoders each connected to the address lines. 
     In accordance with a further feature of the invention, the decoder of each of the first and second cell subarrays is one of the group consisting of a row decoder and a column decoder. 
     In accordance with an added feature of the invention, the connection area is rectangular and has four corner areas, the cell arrays are each rectangular, each of the four side edges of the connection area have a respective length, four of the cell arrays adjoin a respective one of the four side edges of the connection area and each of the four cell arrays have a side edge with a length equal to the respective length of each of the four side edges, others of the cell arrays are respectively disposed in each of the four corner areas, and an overall area defined by the connection area and the cell arrays is rectangular. 
     In addition, it is advantageous to construct the connection area and the cell arrays rectangularly, a cell array with a side edge of an appropriate size adjoining each side edge of the connection area. In each case, a further cell array is disposed in the corner areas of the connection area. Such a memory configuration embodiment has a rectangular outer contour. Therefore, the memory configuration is particularly suitable for a standard housing having a side edge ratio of 2:1. 
     In accordance with an additional feature of the invention, a line decoder or a row decoder is constructed in the areas of the side edges of a cell array that adjoins another cell array or the connection area. As such, the line or row decoder is disposed relatively close to the central connection area so that the signal paths for reading data out or writing data into the cell arrays are relatively short. 
     In accordance with yet another feature of the invention, the connection area has transverse sides, the connecting pads include connecting pad rows, a first row, a second row, a third row, and a fourth row of the connecting pad rows are disposed at a predefined distance parallel to the transverse sides of the connection area, a fifth row and a sixth row of the connecting pad rows are disposed at a predefined distance parallel to the longitudinal sides of the connection area, the first and second rows and the third and fourth rows are respectively disposed on a given line and are disposed at a predefined distance from one another, and the fifth row and the sixth row are respectively disposed centrally with respect to the first and third rows and the second and fourth rows. 
     In accordance with yet a further feature of the invention, the fifth row and the sixth row are respectively disposed between the first, second, third, and fourth rows. 
     In accordance with yet an added feature of the invention, the is fifth row and the sixth row are respectively disposed between the first and third rows and the second and fourth rows and the longitudinal edges of the connection area. 
     In a preferred embodiment, the bonding pads in the connection area are disposed in the form of four rows, the four rows being disposed parallel to the four outer edges of the connection area. As such, a symmetrical distribution of the connecting pads is made possible. 
     In accordance with yet an additional feature of the invention, there are provided peripheral circuits for operating the cell arrays, the peripheral circuits connected to the cell arrays and disposed in the connection area. 
     It is advantageous to configure peripheral circuits in the central connection area. The peripheral circuits are, therefore, virtually equally far removed from all the cell arrays, so that propagation time differences between the signals from various cell arrays are relatively small. 
     In accordance with again another feature of the invention, a cell array preferably has approximately the same size as the connection area. 
     In accordance with again a further feature of the invention, each cell array is once more divided into two cell subarrays. 
     In accordance with a concomitant feature of the invention, the connection area and/or the cell arrays are twice as long as they are wide. 
     Other features that are considered as characteristic for the invention are set forth in the appended claims. 
     Although the invention is illustrated and described herein as embodied in a memory configuration with a central connection area, it is, nevertheless, not intended to be limited to the details shown because various modifications and structural changes may he made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims. 
     The construction and method of operation of the invention, however, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a diagrammatic illustration of a first memory configuration according to the invention; 
     FIG. 2 is a diagrammatic illustration of a second memory configuration according to the invention; and 
     FIG. 3 is a diagrammatic illustration of a third memory configuration according to the invention. 
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Referring now to the figures of the drawings in detail and first, particularly to FIG. 1 thereof, there is shown a memory configuration that, in terms of the external contour, is constructed rectangularly. A longitudinal edge  24  of the memory configuration is virtually twice as long as a transverse edge  25  of the memory configuration. The memory configuration is, therefore, suitable for incorporation in a standard housing having a side ratio of approximately 2:1. Such a side ratio is used, for example, in the case of an intermediate memory size of 128 megabits, 512 megabits, 2 gigabits, and so on. Because of the external contours of the memory configurations, it is possible, for example, to incorporate the 512 megabit DRAM as early as one technological generation earlier into a standard housing than in architectures from the prior art. 
     Disposed at the center of the memory configuration is a connection area  1  having a rectangular construction. The side ratio of the connection area  1  has a ratio between the longitudinal side and the transverse side of approximately 2:1. Formed in the connection area  1  are bonding pads  14  that are disposed in rows. A bonding pad  14  is used for connecting a bonding wire that is led from the bonding pad to connecting pins of a housing. The bonding pads are connected to circuits and cell arrays. The rows  15 ,  16 ,  17 ,  18 ,  19 ,  20  are respectively disposed parallel to and at a predefined distance from the transverse edge and the longitudinal edge of the connection area  1 . In the exemplary embodiment described, first and second rows  15 ,  16  are disposed at a predefined distance from the upper transverse edge of the connection area  1 , the first and second rows  15 ,  16  in turn having a predefined distance from each other and, symmetrically in each case, being at the same distance from the two longitudinal edges. 
     Furthermore, third and fourth rows  17 ,  18  are formed and are disposed mirror-symmetrically in relation to the first and second row  15 ,  16  in the connection area  1 . Fifth and sixth rows  19 ,  20  of bonding pads  14  are respectively disposed at a predefined distance from and parallel to the longitudinal edges. The fifth and sixth rows  19 ,  20  are disposed in the intermediate area by which the first and second and third and fourth rows  15 ,  16 ,  17 ,  18  are spaced apart. As such, a symmetrical distribution of the bonding pads  14  is achieved. Therefore, a relatively large amount of space for welding the bonding pads  14  to bonding wires is provided and, in addition, the cell arrays are disposed around the bonding pads at virtually the same distance. However, other configurations of bonding pads, such as the configuration in one row, are also possible. 
     The connection area  1  is surrounded in the form of a ring by a first, second, third, fourth, fifth, sixth, seventh, eighth cell array  2 ,  3 ,  4 ,  5 ,  6 ,  7 ,  8 ,  9 . The cell arrays are constructed in form and size corresponding to the connection area  1 . A cell array constitutes a matrix-like memory array with memory cells. In addition, a cell array is disposed on each longitudinal and transverse edge of the connection area  1 , so that in each case a transverse edge of two cell arrays  9 ,  5  respectively adjoins the upper and lower transverse edge of the connection area  1 , and the longitudinal edges of the fourth and eighth cell arrays  5 ,  9  and the connection area  1  form a straight line. A side edge of a second and sixth cell array  3 ,  7  respectively adjoins a side edge of the connection area  1 , the second and sixth cell arrays  3 ,  7  being disposed such that the transverse edges of the second and sixth cell array and the connection area  1  in each case form a straight line. 
     Disposed in the corner areas are first, third, fifth and seventh cell arrays  2 ,  4 ,  6 ,  8 , such that the outer edges of the cell arrays form a rectangular contour. The cell arrays  2  to  9  have an identical construction. Each cell array has a row decoder  10  with row lines  12  and a column decoder  11  with column lines  13 . Through the row and column decoders  10 ,  11 , contact is made with the individual memory cells in the memory array, which are located at respective crossing points of the row select lines and column select lines  12 ,  13 . Each row decoder  10  and column decoder  11  is electrically connected to bonding pads  14 . The row decoders  10  are disposed along the longitudinal edges in the respective cell arrays. The column decoders  11  are disposed adjacent to the transverse edges in the respective cell array. The row decoders  10  and column decoders  11  are always disposed at edges that adjoin a cell array or a connection area  1 . Thus, the row decoders  10  and column decoders  11  are located relatively close to the connection area  1 , so that the signal paths between the row decoders  10 , the column decoders  11 , and the connecting pads  14  and/or the peripheral circuits  23  are relatively short. 
     The connection area  1  has a plurality of peripheral circuits  23  that are electrically connected to bonding pads  14  and/or to the cell arrays. The peripheral circuits  23  provided are, for example, amplifier circuits, control logic, and further circuits that are needed to operate the memory configuration. 
     FIG. 2 illustrates a further embodiment of a memory configuration in which, as compared with the memory configuration of FIG. 1, the previous cell arrays  2  to  9  are each subdivided into a first and second cell subarray  21 ,  22 . Each cell subarray  21 ,  22  has its own column decoder  11 . Thus, each cell array  2  to  9  has a row decoder  10  and two column decoders  11 . Data access to the data belonging to a row select line is, therefore, quicker because the bit lines are shorter. 
     The cell arrays  2  to  9  are disposed annularly around the connection area  1 , corresponding to the embodiment of FIG. 1. A further difference from the embodiment of FIG. 1 is in the configuration of the bonding pads  14 . The first, second, third, and fourth rows  15 ,  16 ,  17 ,  18  of bonding pads  14  are disposed in accordance with FIG.  1 . Although the fifth and sixth rows  19 ,  20  are likewise disposed parallel to the longitudinal edges, they are at a significantly smaller distance from the side edges and are disposed between the first, second, third, and fourth rows  14 ,  15 ,  16 ,  17 ,  18  and the longitudinal edges. In addition, peripheral circuits  23  are formed in the connection area  1 . 
     FIG. 3 illustrates a further embodiment of a memory configuration, in which each cell array  2  to  9  is subdivided into a first and second cell subarray  21 ,  22 , corresponding to the embodiment of FIG.  2 . In the embodiment of FIG. 3, however, each cell array  2  to  9  has a column decoder  11  along a longitudinal edge. In addition, in each case a row decoder  10  for a cell subarray  21 ,  22  is disposed in each cell array. Otherwise, the construction of the cell arrays corresponds to the construction from FIG.  2 . 
     A further difference from FIG. 2 is in the configuration of the bonding pads  14  in the connection area  1 . Although the first, second, third, and fourth rows  14 ,  15 ,  16 ,  17 ,  18  are disposed so as to correspond to FIG. 2, the fifth and sixth rows  19 ,  20  are formed parallel to the longitudinal edges. The fifth row  19  is disposed between the second and fourth rows  16 ,  18 , and the sixth row  20  is disposed between the first and third rows  15 ,  17 . Peripheral circuits  23  are likewise integrated in the connection area  1 . 
     All the peripheral circuits that are needed to operate the memory configuration are preferably disposed in the first connection area of the memory configurations of FIGS. 1,  2 , and  3 .

Technology Category: 5