Abstract:
A method for arranging I/O lines in a multi-memory bank having, a plurality of memory banks, an I/O sense amplifier block, a plurality of I/O sense amplifiers, a plurality of column-decoder blocks, a plurality of local I/O line pairs, and a plurality of global I/O line pairs. Memory chip operating efficiency is improved, for example, by dividing a plurality of memory banks by an I/O sense amplifier block, alternating the positions of I/O line transfer transistors and sense amplifier driving transistors, and intersecting global I/O line pairs thereby easing bank addressing and enhancing the speed of operation.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a multi-bank semiconductor memory device and a method for arranging input and output (I/O) lines. More particularly, the invention relates to an improved architecture leading to efficiency in chip manufacture and design. 
     2. Description of the Related Art 
     A semiconductor memory device may employ different architecture such as multi-bit architecture or multi-bank architecture to enhance performance. In multi-memory bank architecture, memory banks can be readily accessed independently and selectively by a bank address method. 
     In such a multi-memory bank architecture, a write operation, a read operation, and an interrupt operation can be performed in different memory banks. The multi-memory bank architecture includes a bank data bus, which may be a global I/O line, carrying the data read from each memory bank and the data to be written. 
     Further, each memory bank is divided into a plurality of memory blocks according to the increasing number of memory cells included in one memory bank. The plurality of memory blocks are connected to global I/O lines through a plurality of local I/O lines. Accordingly, each memory block should include sense amplifier blocks, word-line driving blocks, sense amplifier driving circuits, and line transfer circuits because each memory bank is divided into a plurality of memory blocks. 
     The above-described multi-memory bank architecture is disclosed in U.S. Pat. No. 5,781,495. Specifically, the disclosed architecture includes a plurality of global I/O line pairs passing through the upper side of a memory cell array and extended across a plurality of memory banks. 
     The efficiency of such multi-memory bank architecture suffers however due to the added size. 
     Therefore a need exists for a multi-memory bank architecture to improve cell efficiency and chip efficiency. 
     SUMMARY OF THE INVENTION 
     One object of the present invention is to provide a multi-bank semiconductor memory device and a method for arranging I/O lines for improving chip efficiency by dividing a plurality of memory banks with I/O sense amplifier blocks. 
     Another object of the present invention is to provide a multi-bank semiconductor memory device and a method for arranging I/O lines which increases the efficiency of chip manufacture and design by alternately disposing I/O line transfer transistors and sense amplifier driving transistors. 
     Still another object of the present invention is to provide a multi-bank semiconductor memory device and a method for arranging I/O lines for ease of bank addressing by crossing global I/O line pairs. 
     Another object of the present invention is to provide a multi-bank semiconductor memory device and a method for arranging I/O lines to increase chip operating speed through an equalizing operation of global I/O line pairs in a write-interrupt-read mode. 
     To accomplish the above-mentioned objects, a device of the present invention comprises: a plurality of memory banks arranged in the direction of a row; an I/O sense amplifier block which is disposed between adjacent pairs of a plurality of the memory banks, and which includes a plurality of I/O sense amplifiers arranged in the direction of a column; a plurality of column-decoder blocks disposed between each adjacent pair of the memory banks; a plurality of local I/O line pairs extended in each of the memory banks through each memory block therein, in the direction of a column; a plurality of global I/O line pairs, which are extended in one memory bank of each adjacent pair of the memory banks in the direction of a row, which intersect each other on each column-decoder block, and which are extended in the other memory bank in the direction of the other row in the word-line driving block previously containing the intersecting global I/O line pairs. 
     Each pair of local I/O line pair is preferably disposed on a plurality of sense amplifier block columns arranged in each memory bank in the direction of a row. A pair of local I/O line pair is disposed on each sense amplifier block column. Each pair of the global I/O line pair is disposed on a plurality of word-line driving block rows, the word-line driving blocks are arranged in each memory bank in the direction of a column. A pair of the global I/O lines is disposed at each of the word-line driving block rows. Each of the global I/O line pair is connected with the local I/O line pair crossed at the identical word-line driving block row by having an identical address. In memory banks where global I/O line pairs are not connected with the local I/O line pairs, the global I/O line pair is disposed on adjacent word-line driving block rows. The sense amplifier block columns and sense amplifier driving circuit blocks are disposed in the region of word-line driving block rows where the global I/O line pairs are not connected to the local I/O line pairs. Each of the plurality of global I/O line pairs includes a plurality of equalizer means, which are connected to an end point, and middle points between each memory bank and column-decoder. A plurality of the equalizer means perform an equalizing operation in a write-interrupt-read mode. 
     According to the present invention, a method for arranging I/O lines of a multi-bank semiconductor memory device having a plurality of I/O sense amplifiers in the direction of a column between adjacent pairs of a plurality of memory banks arranged in the direction of a row, comprises the following steps of: arranging a plurality of local I/O line pairs in the direction of a row, which are extended in each memory bank in the direction of a column, having a column-decoder disposed between each adjacent memory bank in a memory area; and arranging a plurality of global I/O line pairs, which are extended in one memory bank of each adjacent pair of the memory banks in the direction of a row, which intersect each other on each column-decoder block, and which are extended in the other memory bank in the direction of the other row in the word-line driving block previously containing the intersecting global I/O line pairs. 
     Wherein, it is preferred that each of the plurality of global I/O line pair includes a plurality of equalizer means which are connected to an end point, and middle points between each memory bank and column-decoder. The plurality of equalizer means perform an equalizing operation in a write-interrupt-read mode. 
     Also, a device of the present invention comprises: a pair of element formation areas divided on a semiconductor wafer; a peripheral circuit area disposed on the center of the element formation area for dividing each element formation area into a pair of sub-element formation areas; an input/output sense amplifier block disposed on the center of the sub-element formation area for dividing each sub-element formation area into a pair of memory areas; a column-decoder block disposed on the center of the memory area for dividing each memory area into a pair of memory banks; and a plurality of global I/O line pairs. 
     Wherein, a first pair of global I/O line pair is extended in a memory bank adjacent to an I/O sense amplifier block in the direction of a first row. A second pair of global I/O line pair is extended in the direction of a second row adjacent to the first row. The four global I/O line pair intersect each other on the column-decoder block. The first pair of global I/O line pair is extended on other memory bank adjacent to the column-decoder in the direction of the second row. The second pair of global I/O line pair is extended in the first row. The global I/O line pairs are repeatedly disposed in the direction of a column. 
     Global I/O line pairs are connected to I/O sense amplifiers different from each other, respectively. The first pair of global I/O line pair of the intersecting global I/O line pairs are connected to local I/O line pairs in a first memory bank. The second pair of global I/O line pair of the intersecting global I/O line pairs are connected to local I/O lines pairs in a second memory bank. Global I/O line pair connect to local I/O line pair having the identical addresses in each memory bank in an I/O sense amplifier. The local I/O line pairs are disposed on a plurality of sense amplifier block columns arranged on each memory bank in the direction a row, respectively. One pair of local I/O line pair is disposed on each sense amplifier block column. Each pair of global I/O line pair is disposed on a plurality of word-line driving block rows. The word-line driving blocks are arranged in each memory bank in the direction of a column. One pair of global I/O line pair is disposed in each word-line driving block row. Each global I/O line pair is connected to the local I/O line pair intersected at word-line driving block row arranged along a first row of each memory bank having the identical address with the local I/O line pair. A sense amplifier driving circuit block is disposed at the intersection of word-line driving block rows arranged along a second row and the sense amplifier block columns. Each global I/O line pair includes a plurality of equalizer means that are connected to an end point, and middle points between each memory bank and column-decoder block. And the plurality of equalizer means perform an equalizing operation in a write-interrupt-read mode. 
     Further objects and advantages of the invention can be more fully understood from the following detailed description taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a schematic diagram of a multi-bank memory device with crossed global I/O pairs according to the present invention. 
     FIG. 2 is a schematic diagram of a multi-bank memory device according to one preferred embodiment of the present invention. 
     FIG. 3 is a schematic diagram of a line-input circuit for connecting an input portion of an I/O line sense amplifier to the global I/O lines pair shown in FIG.  2 . 
     FIG. 4 is a schematic diagram of a line transfer circuit for connecting the global I/O lines pair to the local I/O lines pair shown in FIG.  2 . 
     FIG. 5 is a schematic diagram of an equalizer means of the global I/O lines pair shown in FIG.  2 . 
     FIG. 6 a timing diagram of a write-interrupt-read operation of FIG.  2 . 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIG. 1, a memory device includes memory bank pairs  10   a  and  10   b,  and an I/O line sense amplifier block IOSA. The memory bank pair  10   a  includes a first memory bank MB 1 , a first column-decoder block CD 1  and a second memory bank MB 2 . The memory bank pair  10   b  includes a third memory bank MB 3 , a second column-decoder block CD 2  and a fourth memory bank MB 4 . Each memory bank MB 1 ˜MB 4  is divided into a plurality of memory blocks, and each memory block includes two unit arrays UA 1  and UA 2 . Each memory block is divided into unit array columns by sense amplifier blocks SA 1 , SA 2  and SA 3 . Each pair unit arrays is divided into rows by word-line driving blocks SWD. 
     Sense amplifier driving circuit blocks SD 1 ˜SD 4  and line transfer circuit blocks LT 1 ˜LT 4  are alternately disposed in the direction of a column, at each intersection of sense amplifier block columns SAC 1 ˜SAC 3  and word-line driving block rows WDR 1  and WDR 2 . 
     Each pair of the local I/O line pairs (LIO 1 , LIO 3 ), (LIO 2 , LIO 4 ) and (LIO 1 , LIO 3 ) passes over one of the sense amplifier blocks SAC 1 ˜SAC 3 . 
     Each pair of the global I/O line pairs (GIO 11 , GIO 12 ) and (GIO 21 , GIO 22 ) passes over the word-line driving block rows WDR 1  and WDR 2  alternately. Each global I/O line pair passing over a first word-line driving block in a first memory bank and a second word-line driving block in a second memory bank. 
     The spelling ‘i’ of ‘GIOij’ refers to a memory bank number, and ‘j’ refers to a local I/O lines pair number in the memory bank. Referring to FIGS. 4 and 6, a local I/O line pair LIOj is composed of the local lines LIO and LIOB. Referring to FIGS. 4,  5 , and  6  a global I/O line pair GIOij is composed of the global lines GIO and GIOB. 
     The global I/O line pair GIO 11  is connected with the first local I/O line pair LIO 1  of the first memory bank MB 1  at line transfer circuit blocks LT 1  and LT 3 . The global I/O line pair GIO 12  is connected with the second local I/O line pair LIO 2  of the first memory block MB 1 , at the line transfer circuit block LT 2 . 
     The global I/O line pair GIO 21  is connected to the first local I/O line pair LIO 1  of the second memory bank MB 2  at the line transfer circuit blocks LT 1  and LT 3 . The global I/O line pair GIO 22  is connected to the second local I/O line pair LIO 2  of the second memory bank MB 2  at the line transfer circuit block LT 2 . 
     The pair of global I/O line pairs (GIO 11 , GIO 12 ) and (GIO 21  and GIO 22 ) intersect each other at the column-decoder block CD 1 . In the second memory bank MB 2 , the global I/O line pairs GIO 11  and GIO 12  pass along the word-line driving block row WDR 2 , including the sense amplifier driving circuit blocks SD 1 ˜SD 3 . In the first memory bank MB 1 , the global I/O line pairs GIO 21  and GIO 22  pass over the word-line driving block row WDR 2 , including the sense amplifier driving circuit block SD 1 ˜SD 3 . 
     The global I/O line pairs GIO 11  and GIO 21  are connected to the I/O line sense amplifier IOSA 1 , and the global I/O line pairs GIO 12  and GIO 22  are connected to the I/O line sense amplifier IOSA 2 . 
     Accordingly, the read and write data from each memory bank addressed simultaneously are respectively provided to the I/O line sense amplifiers through the global I/O line pairs, these are disposed separately so that they do not interfere each other. 
     The positioning of the global I/O line pairs makes the capacitive load of the global I/O line pairs (GIO 11 , GIO 12 ) and (GIO 21 , GIO 22 ) equal. 
     According to the method above, pair of global I/O line pairs (GIO 31 , GIO 32 ) and (GIO 41  and GIO 42 ) are disposed in the memory bank pair  10   b.    
     Accordingly, the global I/O line pairs GIO 11 , GIO 21 , GIO 31  and GIO 41  are connected to the I/O line sense amplifier IOSA 1  by multiplexing, respectively. The global I/O line pairs GIO 12 , GIO 22 , GIO 32  and GIO 42  are connected to the I/O line sense amplifier IOSA 2  by multiplexing, respectively. Such a connection improves bank addressing. 
     Each of the global I/O line pairs includes equalizer means EQ 1 , EQ 2 , and EQ 3 . The equalizer means are connected to a line end point, and middle points between each memory bank and column-decoder block. The equalizer means equates the global I/O line pair in a write-interrupt-read mode to make a high-speed operation possible. 
     FIG. 2 illustrates a preferred embodiment of a multi-bank memory device according to the present invention. The multi-bank memory device of FIG. 2 includes a pair of element formation areas  100 A and  100 B divided on a semiconductor wafer. Each element formation area  100 A and  100 B is divided into a pair of sub-element formation areas  120 A and  120 B by a peripheral circuit area  110  disposed between the sub-elements. Each of the sub-element formation areas  120 A and  120 B is divided into a pair memory areas  140 A and  140 B by the I/O sense amplifier block  130 . Each of the memory areas  140 A and  140 B is divided into a pair memory banks  160 A and  160 B by the column-decoder block  150  disposed between the memory banks. 
     At each of the memory banks  160 A and  160 B, four memory blocks ME 1 ˜ME 4  and five word-line driving block rows WDR 1 ˜WDR 5  are alternately disposed in the direction of a column. Each of the even numbered word-line driving block rows WDR 2  and WDR 4  includes two word-line driving blocks SWD 1  and SWD 2 , and three line transfer circuit blocks LT 1 ˜LT 3 . Each of the odd numbered word-line driving block rows WDR 1 , WDR 3  and WDR 5  includes two word-line driving blocks SWD 1  and SWD 2 , and three sense amplifier driving circuit blocks SD 1 ˜SD 3 . 
     At each of the memory blocks ME 1 ˜ME 4 , two unit arrays UA 1  and UA 2 , and three sense amplifier blocks SA are alternately disposed in the direction of a row. A sense amplifier block column SAC 1  comprises four sense amplifier blocks SA 1  disposed in the same column, two line transfer circuit blocks LT 1  disposed at the intersection area of the even numbered word-line driving block rows WDR 2  and WDR 4 , and three sense amplifier driving circuit blocks SD 1  disposed at the intersection area of the odd numbered word-line driving block rows WDR 1 , WDR 3  and WDR 5 . 
     On each of the sense amplifier driving block columns SAC 1 ˜SAC 3 , a pair of local I/O line pairs (LIO 1 , LIO 3 ), (LIO 2 , LIO 4 ), and (LIO 1 , LIO 3 ) pass, respectively, in the direction of the sense amplifier driving block columns. 
     On four word-line driving block rows WDR 2 ˜WDR 5 , a pair of global I/O line pairs (GIO 11 , GIO 12 ), (GIO 21 , GIO 22 ), (GIO 13 , GIO 14 ) and (GIO 23 , GIO 24 ) pass, respectively, in the direction of the word-line driving block rows. 
     On the memory bank  160 B adjacent to the I/O sense amplifier block  130 , a pair of the global I/O line pair GIO 21  and GIO 22  is extended along a first row WDR 2 . A pair of the global I/O line pair GIO 11  and GIO 12  is extended along a second row WDR 3  adjacent to the first row WDR 2 . On the column-decoder block  150 , the two pairs of the global I/O line pair (GIO 11 , GIO 12 ) and (GIO 21 , GIO 22 ) intersect each other. On the memory bank  160 A adjacent to the column-decoder block  150 , the pair of the global I/O line pair GIO 21  and GIO 22  is extended along the second row WDR 3 . A pair of the global I/O line pair GIO 11  and GIO 12  is extended along the first row WDR 2 . 
     On the memory bank  160 B, adjacent to the I/O sense amplifier block  130 , a pair of the global I/O line pair GIO 23  and GIO 24  is extended along a first row WDR 4 . A pair of the global I/O line pair GIO 13  and GIO 14  is extended along the second row WDR 5  adjacent to the first row WDR 4 . On the column-decoder block  150 , two pairs of the global I/O line pair (GIO 23 , GIO 24 ) and (GIO 13  and GIO 14 ) intersect each other. On the other memory bank  160 A adjacent to the column-decoder block  150 , the pair of the global I/O line pair GIO 23  and GIO 24  is extended along the second row WDR 5 . The pair of the global I/O line pair GIO 13  and GIO 14  is extended along the first row WDR 4 . 
     In the memory bank  160 A, the global I/O line pair GIO 11  is connected to the local I/O line pair LIO 1  at the line transfer circuit blocks LT 1  and LT 3  of the word-line driving block row WDR 2 . The global I/O line pair GIO 12  is connected to the local I/O line pair LIO 2  at the line transfer circuit blocks LT 2  of the word-line driving block row WDR 2 . The global I/O line pair GIO 13  is connected to the local I/O line pair LIO 3  at the line transfer circuit blocks LT 1  and LT 3  of the word-line driving block row WDR 4 . 
     In the memory bank  160 B, the global I/O line pair GIO 21  is connected to the local I/O line pair LIO 1  at the line transfer circuit blocks LT 1  and LT 3  of the word-line driving block row WDR 2 . The global I/O line pair GIO 22  is connected to the local I/O line pair LIO 2  at the line transfer circuit block LT 2  of the word-line driving block WDR 2 . The global I/O line pair GIO 23  is connected to the local I/O line pair LIO 3  at the line transfer circuit blocks LT 1  and LT 3  of the word-line driving block row WDR 4 . 
     The global I/O line pair (GIO 11 , GIO 12 ), (GIO 21 , GIO 22 ), (GIO 13 , GIO 14 ) and (GIO 23 , GIO 24 ) include the equalizer means EQ 1 , EQ 2  and EQ 3 . The equalizer means are connected to the end points of each global I/O line pair, separated from the I/O line sense amplifier block  130  to avoid interference. The equalizer means are also connected at the middle points between the memory banks  160 A and  160 B and the column-decoder block  150 . 
     According to the method above, the pairs of global I/O line pair (GIO 41 , GIO 42 ), (GIO 31 , GIO 32 ), (GIO 43 , GIO 44 ) and (GIO 33 , GIO 34 ) are disposed in a memory area  140 B symmetrically with the above-described memory area  140 A. 
     Accordingly, the I/O line sense amplifier IOSA 1  is connected to the global I/O line pairs GIO 11 , GIO 21 , GIO 31  and GIO 41 , which are connected to the local I/O line pair LIO 1  of the four memory banks, respectively. The I/O line sense amplifier IOSA 2  is connected to the global I/O line pairs GIO 12 , GIO 22 , GIO 32  and GIO 42 , which are connected to the local I/O line pair LIO 2  of the four memory banks, respectively. The I/O line sense amplifier IOSA 3  is connected to the global I/O line pairs GIO 13 , GIO 23 , GIO 33  and GIO 43 , which are connected to the local I/O line pair LIO 3  of the four memory banks, respectively. The I/O line sense amplifier IOSA 4  is connected to the global I/O line pairs GIO 14 , GIO 24 , GIO 34  and GIO 44 , which are connected to the local I/O line pair LIO 4  of the four memory banks, respectively. 
     Therefore, the same I/O line pairs of four memory banks are connected simultaneously to one of the I/O line sense amplifiers by having the same addresses. So in the I/O line sense amplifier, it is possible to input and output the data by multiplexing or de-multiplexing four global I/O line pairs respectively connected with the memory banks. 
     FIG. 3 illustrates a line-input circuit for connecting an input portion of the I/O line sense amplifier to a global I/O line pair of FIG.  2 . The line-input circuit  300  includes a switching means  310 , an equalizer means  320 , an equalizer control means  330 , a precharge means  340 , and a precharge control means  350 . 
     The switching means  310  includes transfer gates TG 1  and TG 2  and inverters INV 1  and INV 2 . The switching means  310  turns on the transfer gates TG 1  and TG 2  in an active region, that is, in the high state of a bank information signal PIOMUX and connects global I/O line pairs GIO and GIOB with input line pairs SGIO and SGIOB of the I/O line sense amplifier. 
     The equalizer means  320  includes a NMOS transistor M 1  and PMOS transistors M 2 , M 3  and M 4  connected between the global I/O line pairs GIO and GIOB. The equalizer control means  330  includes a NAND gate NAND 1  and an inverter INV 3 . 
     Accordingly, the transistors of the equalizer means  320  are turned on in response to the equalizer control signal IOPRB which becomes active in response to a write-interrupt-read mode, and the global I/O line pairs GIO and GIOB are equated by a power supply voltage VCC. 
     The precharge means  340  includes PMOS transistors M 5 ˜M 10  connected between the global I/O line pairs GIO and GIOB. The precharge control means  350  includes a NAND gate NAND 2  and a NOR gate NOR 1 . 
     Accordingly, in case that a multi-bit mode signal DCA9112D and a write-interrupt-read signal PDT selects a corresponding bank by using a bank information signal PIOMUX, the global I/O line pairs GIO and GIOB are precharged by a power supply voltage. 
     FIG. 4 illustrates a line transfer circuit for connecting the global I/O line pairs with the local I/O line pairs of FIG.  2 . The line transfer circuit LT of FIG. 4 includes a switching means  410  and an equalizer means  420 . 
     The switching means  410  includes transfer gates TG 3  and TG 4 , and connects the local I/O line pair LIO and LIOB with the global I/O line pair GIO and GIOB in response to a non-active region of an equalizer control signal PLAEQ and an active region of a line transfer signal LANG. 
     The equalizer means  420  includes transistors M 11 , M 12  and M 13  connected between the local I/O line pair LIO and LIOB, and equates the local I/O line pair LIO and LIOB in response to an active region of the equalizer control means PLAEQ with 1/2 VCC. 
     FIG. 5 illustrates the equalizer means of the global I/O line pairs shown in FIG.  2 . The equalizer means EQ 1 ˜EQ 3  of FIG. 2 comprises a PMOS transistor M 14  connected between the global I/O line pair GIO and GIOB. Each of the equalizer means EQ 1 ˜EQ 3  is turned on responding to an equalizer control signal IOPRB which becomes active in response to a write-interrupt-read mode, and equates the global I/O line pair GIO and GIOB. 
     FIG.6 shows a timing diagram explaining a write-interrupt-read operation of FIG. 2 . First, an ACT command (row active command) is inputted in response to a clock signal CLK, and then the equalizer control signal PLAEQ is changed from an active state to a non-active state in response to the ACT command, so that the line transfer signal LANG becomes active. Accordingly, the local I/O line pair LIO and LIOB are connected with the global I/O line pair GIO and GIOB through the line transfer circuit LT so that 1/2 VCC is changed to VCC. 
     Next, a DCA9112D signal, a PIOMUX signal and a PDT signal become active responding to a write command so that the external data is applied to the global I/O line pair GIO and GIOB. Therefore, one line of the global I/O line pair GIO and GIOB is transited to a predetermined level in response to the data applied to the global I/O line pair GIO and GIOB. In such a read operation, if an interrupt operation is performed and a read operation is inputted, the global I/O line pair GIO and GIOB are equated by VCC in response to a PDT signal, an IOPRB signal and an IOPRBD signal. Next, the data read from an addressed cell is outputted to an output terminal, and then the I/O line pair is precharged by a precharge operation and recovered to the state prior to an ACT operation. 
     As described above, the present invention has the following effects. 
     First, the invention improves chip efficiency by dividing a plurality of memory banks with I/O sense amplifier blocks. 
     Second, alternating the positions of I/O line transfer transistors and sense amplifier driving transistors leading to efficiency in manufacture and design. 
     Third, improving bank addressing by crossing global I/O line pairs. 
     Fourth, and improving an equalizing operation of global I/O line pairs in a write-interrupt-read mode. 
     The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.