Semiconductor memory device

A semiconductor memory device includes first wirings above a substrate and extending in a first direction, second wirings above the first wirings and extending in a second direction crossing the first direction, third wirings above the second wirings and extending in the first direction, memory cells between the first and second wirings and between the second and third wirings, a first multiplexer that extends in the second direction, is connected to the first wirings, and is provided in a first region which overlaps with the first, second, and third wirings in a third direction that crosses the first and second directions, and a second multiplexer that extends in the first direction, is connected to the second wirings, and is provided in a second region which overlaps with the first, second, and third wirings in the third direction.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2019-041749, filed Mar. 7, 2019, the entire contents of which are incorporated herein by reference.

FIELD

BACKGROUND

A cross-point type memory device using a variable resistance element as a memory cell array is attracting attention because the device is capable of easily implementing a large-capacity memory device as compared to other devices of the related art.

In the cross-point type memory device, a large number of wirings called bit lines and word lines are cross-arranged (e.g., arranged orthogonal to each other), and a memory cell is formed between the bit line and the word line. Writing of one memory cell is performed by applying a voltage or a current to the bit line and the word line connected to the memory cell.

DETAILED DESCRIPTION

Embodiments provide a semiconductor memory device that may achieve size reduction.

In general, according to one embodiment, the semiconductor memory device includes a substrate, a plurality of first wirings above the substrate in a first plane parallel to a substrate surface, each extending in a first direction, a plurality of second wirings above the plurality of first wirings in a second plane parallel to the substrate surface, each extending in a second direction crossing the first direction, a plurality of third wirings above the plurality of second wirings in a third plane parallel to the substrate surface, each extending in the first direction, a plurality of memory cells provided between the plurality of first wirings and the plurality of second wirings, and between the plurality of second wirings and the plurality of third wirings, respectively, a first multiplexer that extends in the second direction and is provided in a first region which overlaps with the plurality of first, second, and third wirings in a third direction that crosses the first and second directions, a plurality of first connection wirings, each extending in the third direction to connect the first multiplexer to one of the plurality of first wirings, a second multiplexer that extends in the second direction and is provided in a second region which is adjacent to the first region in the first direction, and does not overlap with any of the plurality of first and second wirings in the third direction, a plurality of second connection wirings, each extending in the third direction to connect the second multiplexer to one of the plurality of third wirings, a third multiplexer that extends in the first direction and is provided in a third region which overlaps with the plurality of first, second, and third wirings in the third direction, and a plurality of third connection wirings, each extending in the third direction to connect the third multiplexer to one of the plurality of second wirings.

Hereinafter, embodiments will be described with reference to the drawings. In the drawings, the same or similar portions will be denoted by the same or similar reference numerals.

In the present specification, in order to indicate a positional relationship of components or the like, the upward direction of a drawing is described as “upper,” and the downward direction of the drawing is described as “lower.” In the present specification, the concept of “upper” and “lower” does not necessarily indicate a relationship with respect to a direction of gravity.

First Embodiment

FIG. 1is a block diagram illustrating a configuration of a memory system1of the first embodiment.

The semiconductor memory device of the first embodiment is, for example, a volatile memory such as a dynamic random access memory (DRAM), or a non-volatile memory such as a NAND-type electrically erasable and programmable read-only-memory (EEPROM), a resistive RAM (ReRAM), or a magnetoresistive RAM (MRAM).

The memory system1illustrated inFIG. 1includes a memory cell array MCA, a column decoder CD, a row decoder RD, a sense amplifier SA, a read write buffer RWB, and a peripheral circuit PC.

The memory cell array MCA includes a plurality of memory cells MC two-dimensionally arranged in, for example, a matrix form. The memory cell MC is, for example, a resistance-change type memory such as a ReRAM. The memory cell MC is disposed, for example, at a location where a bit line BL crosses over or under a word line WL. That is, the memory cell array MCA is a so-called cross-point type memory cell array. When viewed from the upper side or the lateral side of the semiconductor substrate, the bit line BL is substantially orthogonal to the word line WL. A plurality of bit lines BL is connected to one ends of the memory cells MC, respectively, in the memory cell array MCA. A plurality of word lines WL is connected to gate terminals of the memory cells MC, respectively, in the memory cell array MCA. The memory cell array MCA is divided into a plurality of banks BNK in one chip. In one example, the sense amplifier SA, a data latch DL, and an address latch AL are separately provided for each bank BNK.

The sense amplifier SA is connected to the memory cell MC via, for example, the bit line BL, and applies a write voltage or a read voltage to the memory cell MC via the bit line BL. The sense amplifier SA writes data into the memory cell MC by applying a write voltage to the memory cell MC, or reads data from the memory cell MC by applying a read voltage to the memory cell MC.

The read write buffer RWB temporarily stores data or an address detected by the sense amplifier SA, for each page, or temporarily stores data or an address to be written into the memory cell array MCA, for each page.

The row decoder RD and the column decoder CD access the memory cell array MCA on the basis of a bank address or a page address to apply a write voltage or a read voltage to the word line WL or the bit line BL. The row decoder RD applies a write voltage or a read voltage to a selected word line among the plurality of word lines WL. The column decoder CD connects a selected bit line that is selected among the plurality of bit lines BL, to the sense amplifier SA. The sense amplifier SA applies a write voltage or a read voltage to the selected bit line. Accordingly, the memory system1may write data into a desired memory cell MC in the memory cell MC, or read data from a desired memory cell MC.

The peripheral circuit PC includes, for example, a voltage generation circuit, a read write engine, an address controller, a command controller, an input/output circuit and the like (not illustrated). The voltage generation circuit GEN generates a voltage of the word line WL or a voltage of the bit line BL, which is required for a data read operation and a data write operation.FIG. 2illustrates a more detailed configuration of the voltage generation circuit GEN. The read write engine controls the column decoder CD and the row decoder RD to write data into a desired memory cell MC in the bank BNK, or reads data from a desired memory cell MC in the bank BNK, according to a command and an address. The read write engine transmits the read data to a DQ buffer of the input/output circuit. The address controller receives a row address, a column address and the like, and decodes these addresses. The command controller receives commands indicating various operations such as a data read operation and a data write operation, and transmits these commands to the read write engine. The input/output circuit IO acquires a command and an address from a terminal CA, transmits the command to the command controller, and transmits the address to the address controller. The command may be a write command that instructs a write operation or a read command that instructs a read operation. The address may be a bank address indicating any bank BNK of the memory cell array MCA, or an address indicating a page or a memory cell MC as a read or write target in the bank BNK. The input/output circuit acquires write data from a DQ terminal, and transmits the write data to the read write buffer RWB. In addition, the input/output circuit receives read data stored in the data latch DL, and outputs the read data through the DQ terminal.

A memory controller (not illustrated) may be provided outside the memory system1to control all of a plurality of memory systems1.

FIG. 2is a block diagram illustrating an example of a more detailed configuration of the bank BNK, the column decoder CD, and the row decoder RD. The bank BNK includes the memory cell array MCA, and may include a plurality of memory cell arrays subdivided corresponding to bit line multiplexers MUX_BL1_1to MUX_BLm_n, and word line multiplexers MUX_WL1_1to MUX_WLm_n. Hereinafter, the subdivided memory cell arrays will be referred to as MCA.

The memory system1includes the memory cell arrays MCA, bit line multiplexers MUX_BL1_1to MUX_BLm_n, and bit line multiplexer MUX_BL0as the column decoders CD, word line multiplexers MUX_WL1_1to MUX_WLm_n, and word line multiplexer MUX_WL0as the row decoders RD, bit line paths P_BL_sel and P_BL_unsel, word line paths P_WL_sel and P_WL_unsel, a selected BL voltage generation circuit GEN_BL_sel, an unselected BL voltage generation circuit GEN_BL_unsel, a selected WL voltage generation circuit GEN_WL_sel, and an unselected WL voltage generation circuit GEN_WL_unsel.

The multiplexer is configured using a switching element such as a metal oxide semiconductor field effect transistor (MOSFET).

The column decoders CD as first decoders include the bit line multiplexers MUX_BL1_1to MUX_BLm_n, and bit line multiplexer MUX_BL0. The bit line multiplexers MUX_BL1_1to MUX_BLm_n are provided corresponding to the memory cell arrays MCA, respectively, and are connected to the plurality of bit lines BL of the memory cell arrays MCA, respectively. Each of m and n is an integer of 1 or more. Each of the bit line multiplexers MUX_BL1_1to MUX_BLm_n connects one selected bit line BL_sel selected from the bit lines BL of the corresponding memory cell array MCA, to a selected bit line path P_BL_sel, and applies a selected bit line voltage VREAD. Each of the bit line multiplexers MUX_BL1_1to MUX_BLm_n connects an unselected bit line BL_unsel other than the selected bit line BL_sel to an unselected bit line path P_BL_unsel, and applies an unselected bit line voltage VUB. Otherwise, each of the bit line multiplexers MUX_BL1_1to MUX_BLm_n places the unselected bit line BL_unsel in a floating state, and does not apply a voltage.

The bit line multiplexer MUX_BL0is connected between the selected BL voltage generation circuit GEN_BL_sel and a plurality of bit line paths, and between the unselected BL voltage generation circuit GEN_BL_unsel and the plurality of bit line paths. The bit line multiplexer MUX_BL0connects one bit line path selected among the plurality of bit line paths, as the selected bit line path P_BL_sel, to the selected BL voltage generation circuit GEN_BL_sel. Also, the bit line multiplexer MUX_BL0connects the unselected bit line path as P_BL_unsel, among the plurality of bit line paths, to the unselected BL voltage generation circuit GEN_BL_unsel.

The bit line paths P_BL_sel and P_BL_unsel are wiring paths which are connected between the bit line multiplexers MUX_BL1_1to MUX_BLm_n and the bit line multiplexer MUX_BL0. For example, 32 or 64 bit line paths are provided. As described above, the bit line multiplexer MUX_BL0selects one among the plurality of bit line paths, and connects the selected bit line path P_BL_sel to the selected BL voltage generation circuit GEN_BL_sel. The selected bit line path P_BL_sel transfers the selected bit line voltage VREAD. Also, the bit line multiplexer MUX_BL0connects the unselected bit line path P_BL_unsel among the plurality of bit line paths to the unselected BL voltage generation circuit GEN_BL_unsel. The bit line path P_BL_unsel transfers the unselected bit line voltage VUB. The selected BL voltage generation circuit GEN_BL_sel as a first power supply circuit generates the selected bit line voltage VREAD to be applied to the selected bit line BL_sel, from an external power supply. The selected bit line voltage VREAD is a high level voltage, and is, for example, several volts in magnitude, such as 2 to 3 volt. The selected bit line path P_BL_sel transfers the selected bit line voltage VREAD to the bit line multiplexers MUX_BL1_1to MUX_BLm_n from the bit line multiplexer MUX_BL0. Each of the bit line multiplexers MUX_BL1_1to MUX_BLm_n, and bit line multiplexer MUX_BL0as the first decoders electrically connect the selected bit line BL_sel among the plurality of bit lines BL to the selected BL voltage generation circuit GEN_BL_sel through the selected bit line path P_BL_sel, and selectively apply the selected bit line voltage VREAD to the selected bit line BL_sel.

The unselected BL voltage generation circuit GEN_BL_unsel as a second power supply circuit generates the unselected bit line voltage VUB to be applied to the unselected bit line BL_unsel, from the external power supply. The unselected bit line voltage VUB is a voltage between the selected bit line voltage VREAD and a selected word line voltage VLOW, and is, for example, VREAD/2. The unselected bit line path P_BL_unsel transfers the unselected bit line voltage VUB to the bit line multiplexers MUX_BL1_1to MUX_BLm_n from the bit line multiplexer MUX_BL0. The bit line multiplexers MUX_BL0and each of bit line multiplexers MUX_BL1_1to MUX_BLm_n as the first decoders electrically connect the unselected bit line BL_unsel to the unselected BL voltage generation circuit GEN_BL_unsel through the unselected bit line path P_BL_unsel, and selectively apply the unselected bit line voltage VUB to the unselected bit line BL_unsel. Otherwise, the bit line multiplexers MUX_BL0and each of bit line multiplexers MUX_BL1_1to MUX_BLm_n do not apply a voltage to the unselected bit line BL_unsel.

The row decoders RD as second decoders include the word line multiplexers MUX_WL1_1to MUX_WLm_n, and word line multiplexer MUX_WL0. The word line multiplexers MUX_WL1_1to MUX_WLm_n are provided corresponding to the memory cell arrays MCA, respectively, and are connected to the plurality of word lines WL of the memory cell arrays MCA, respectively. Each of the word line multiplexers MUX_WL1_1to MUX_WLm_n connects one selected word line WL_sel selected from the word lines WL of the corresponding memory cell array MCA, to a word line path P_WL_sel, and applies the selected word line voltage VLOW. Each of the word line multiplexers MUX_WL1_1to MUX_WLm_n connects an unselected line WL_unsel other than the selected word line WL_sel to a word line path P_WL_unsel, and applies an unselected word line voltage VUX. The word line multiplexer MUX_WL0is connected between the selected WL voltage generation circuit GEN_WL_sel and a plurality of word line paths, and between the unselected WL voltage generation circuit GEN_WL_unsel and the plurality of word line paths. The word line multiplexer MUX_WL0connects one word line path selected among the plurality of word line paths, as P_WL_sel, to the selected WL voltage generation circuit GEN_WL_sel. Also, the word line multiplexer MUX_WL0connects the unselected word line path as P_WL_unsel, among the plurality of word line paths, to the unselected WL voltage generation circuit GEN_WL_unsel.

The word line paths P_WL_sel and P_WL_unsel are wiring paths which are connected between the word line multiplexers MUX_WL1_1to MUX_WLm_n and the word line multiplexer MUX_WL0. For example, 32 or 64 word line paths are provided. As described above, the word line multiplexer MUX_WL0selects one among the plurality of word line paths, and connects the selected word line path P_WL_sel to the selected WL voltage generation circuit GEN_WL_sel. The word line path P_WL_sel transfers the selected word line voltage VLOW. Also, the word line multiplexer MUX_WL0connects the unselected word line path P_WL_unsel among the plurality of word line paths to the unselected WL voltage generation circuit GEN_WL_unsel. The word line path P_WL_unsel transfers the unselected word line voltage VUX. The selected WL voltage generation circuit GEN_WL_sel as a third power supply circuit generates the selected word line voltage VLOW to be applied to the selected word line WL_sel, from the external power supply. The selected word line voltage VLOW is a low level voltage, and is, for example, a ground voltage (0V). The word line path P_WL_sel transfers the selected word line voltage VLOW to the word line multiplexers MUX_WL1_1to MUX_WLm_n from the word line multiplexer MUX_WL0. Each of the word line multiplexers MUX_WL1_1to MUX_WLm_n, and word line multiplexer MUX_WL0as the second decoders electrically connect the selected word line WL_sel among the plurality of word lines WL to the selected WL voltage generation circuit GEN_WL_sel through the selected word line path P_WL_sel, and selectively apply the selected word line voltage VLOW to the selected word line WL_sel.

The unselected WL voltage generation circuit GEN_WL_unsel as a fourth power supply circuit generates the unselected word line voltage VUX to be applied to the unselected word line WL_unsel, from the external power supply. The unselected word line voltage VUX is a voltage between the selected bit line voltage VREAD and the selected word line voltage VLOW, and is, for example, VREAD/2. It is desirable that the unselected word line voltage VUX is substantially the same as the unselected bit line voltage VUB. However, the unselected word line voltage VUX may be different from the unselected bit line voltage VUB. The unselected word line path P_WL_unsel transfers the unselected word line voltage VUX to the word line multiplexers MUX_WL1_1to MUX_WLm_n from the word line multiplexer MUX_WL0. Each of the word line multiplexers MUX_WL1_1to MUX_WLm_n as the second decoders electrically connects the unselected word line WL_unsel to the unselected WL voltage generation circuit GEN_WL_unsel through the unselected word line path P_WL_unsel, and selectively applies the unselected word line voltage VUX to the unselected word line WL_unsel.

In this manner, a voltage difference between the selected bit line voltage VREAD and the selected word line voltage VLOW is applied to a selected memory cell MC_sel connected to the selected bit line BL_sel and the selected word line WL_sel. Accordingly, data is read from the selected memory cell MC_sel or data is written into the selected memory cell MC_sel.

FIGS. 3A to 3care schematic views of a semiconductor memory device100of the embodiment.

Here, an x axis, a y axis perpendicular to the x axis, and a z axis perpendicular to the x axis and the y axis are defined. It is assumed that the surface of a substrate2is disposed in parallel to an xy plane.

FIG. 3Ais a block diagram of the semiconductor memory device100of the embodiment.FIG. 3Bis an example of a schematic sectional view of the semiconductor memory device100of the embodiment, in a section parallel to an xz plane.FIG. 3Cis an example of a schematic sectional view of the semiconductor memory device100of the embodiment, in a section parallel to a yz plane.

The semiconductor memory device100includes one memory cell array MCA illustrated inFIGS. 1 and 2, a multiplexer (e.g., MUX_BL1_1) as the column decoder CD provided for such a memory cell array MCA, and a multiplexer (e.g., MUX_WL1_1) as the row decoder RD provided for such a memory cell array MCA.

The memory system1or the semiconductor memory device100is provided on the substrate2such as a semiconductor substrate.

A first region4is a region in which, for example, one memory cell array MCA is provided. The first region4is provided on the substrate2, for example. The first region4is a rectangular region that has a first side4a, a second side4b, and a third side4cfacing the second side4b, in a plane parallel to the surface of the substrate2. InFIGS. 3A to 3C, the first region4is illustrated as a rectangular region, but is not limited to the rectangular shape. Additionally, the first side4ais provided in parallel to an x direction, and the second side4band the third side4care provided in parallel to a y direction.

A bit line wiring BL06extends parallel to the first side4a, in the first region4on the substrate2. A word line wiring WL08extends parallel to the second side4b, in the first region4above the bit line wiring BL0. A bit line wiring BL110extends parallel to the first side4a, in the first region4on the word line wiring WL08. The memory cells MC are provided between the bit line wiring BL06and the word line wiring WL08, and between the word line wiring WL08and the bit line wiring BL110, respectively.

A bit line multiplexer BL0_MUX14is a part of the column decoders CD and is provided in a second region12along the second side4b, in the first region4between the substrate2and the bit line wiring BL0. For example, the bit line multiplexer BL0_MUX14is formed on the surface of the substrate2by using a known semiconductor device forming process.

A first connection wiring16is provided between the bit line multiplexer BL0_MUX14and the bit line wiring BL0to connect the bit line multiplexer BL0_MUX14to the bit line wiring BL0. The number of the first connection wirings16corresponds to the number of connections between the bit line multiplexer BL0_MUX14and the bit line wiring BL0, but the illustration thereof is omitted inFIG. 3B.

A bit line multiplexer BL1_MUX20is provided in a third region18adjacent to the second region12in the x direction, outside the first region4. Specifically, for example, the bit line multiplexer BL1_MUX20is formed on the surface of the substrate2by using a known semiconductor device forming process. However, a place where the bit line multiplexer BL1_MUX20is provided is not limited thereto.

A second connection wiring22is provided between the bit line multiplexer BL1_MUX20and the bit line wiring BL1to connect the bit line multiplexer BL1_MUX20to the bit line wiring BL1. The number of the second connection wirings22corresponds to the number of connections between the bit line multiplexer BL1_MUX20and the bit line multiplexer BL1although that is not illustrated inFIG. 3B.

A word line multiplexer WL0_MUX_126is provided in a fourth region24along the first side4abetween the third side4cand the second region12, in the first region4between the substrate2and the BL0. Specifically, for example, the word line multiplexer WL0_MUX_126is formed on the surface of the substrate2by using a known semiconductor device forming process.

A word line multiplexer WL0_MUX_228is provided outside the first region4.

A third connection wiring32is provided in a fifth region30adjacent to the fourth region24in the y direction, outside the first region4, to connect the word line multiplexer WL0_MUX_126or the word line multiplexer WL0_MUX_228to the WL0. That is, a multiplexer connected to the word line wiring WL0includes the word line multiplexer WL0_MUX_126provided in the fourth region24and the word line multiplexer WL0_MUX_228provided outside the first region4.

For example, the word line multiplexer WL0_MUX_228is provided in a sixth region34that is adjacent to the third region18in the y direction and adjacent to the fifth region30in the x direction, outside the first region4. Then, for example, the word line multiplexer WL0_MUX_126is connected to a part of the WL0by a third connection wiring32aprovided in the fifth region30, and a wiring31provided in the substrate2. The wiring31is connected to the third connection wiring32a, for example, at the inner side of the paper ofFIG. 3C, as compared to the word line multiplexer WL0_MUX_228. The mode of connection between a part of the WL0and the word line multiplexer WL0_MUX_126is not limited thereto. The word line multiplexer WL0_MUX_2is connected to a third connection wiring32bin the fifth region30. InFIG. 3C, the third connection wiring32aand the third connection wiring32bdo not overlap in the illustration in the x direction. However, in other embodiments, the third connection wiring32aand the third connection wiring32bmay overlap with each other.

An insulator90is provided around the bit line wiring BL0, the word line wiring WL0, the bit line wiring BL1, the memory cell array MCA, the first connection wiring16, the second connection wiring22, the third connection wiring32, the bit line multiplexer BL0_MUX14, the bit line multiplexer BL1_MUX20, the word line multiplexer WL0_MUX_126, and the word line multiplexer WL0_MUX_228, on the substrate2. A barrier metal (not illustrated) is appropriately provided between the insulator90and each BL/WL or the like.

Hereinafter, the operation effect of the embodiment will be described.

FIG. 4is a schematic view of a semiconductor memory device800, according to a comparative example.

In order to reduce the size of a semiconductor memory device, it is desirable that a multiplexer be disposed below the MCA. As for a multiplexer for a BL, it is desirable that the size (length) of a region where the multiplexer is disposed is the same as the length of a region where the BL is disposed. This is because when some of transistors in the multiplexer for the bit line BL are arranged at the same intervals as the bit lines BLs, the length of a wiring that connects the bit lines BL to the multiplexer for the bit lines BL should be shortened as much as possible so that a voltage loss caused by the length of the wiring can be reduced as much as possible. However, when the bit line multiplexer BL0_MUX14is disposed below the first region4as illustrated inFIG. 4, the word line multiplexer WL0_MUX26has no choice but to be disposed outside the first region4, and this is not desirable from the viewpoint of size reduction.

Further, there is a problem in that a region illustrated inFIG. 4, which is adjacent to the third region18where the bit line multiplexer BL1_MUX20is disposed and to a region where the word line multiplexer WL0_MUX26is disposed, becomes a dead space. This is because it is difficult to provide a wiring or the like to the first region where the memory cell array MCA is disposed and to effectively utilize this region.

According to the semiconductor memory device100of the embodiment, the multiplexer connected to the word line wiring WL08is made up of two word line multiplexers that are separately disposed, namely the word line multiplexer WL0_MUX_126provided in the fourth region24along the first side4a, between the third side4cand the second region12, and the word line multiplexer WL0_MUX_228provided outside the first region4. In the embodiment, the third connection wiring32is provided to connect the word line multiplexer WL0_MUX_126or the word line multiplexer WL0_MUX_228to the word line wiring WL08. The size of a region where the third connection wiring32is provided may be reduced as compared to the size of the entire region where the multiplexer is disposed. Thus, it is possible to reduce a size of the semiconductor memory device.

When the word line multiplexer WL0_MUX_228is provided in the sixth region34adjacent to the third region18and the fifth region30, outside the first region4, it is possible to connect the word line multiplexer WL0_MUX_228to the word line wiring WL08by the third connection wiring32(32b) provided in the fifth region30. Thus, it is possible to effectively utilize a semiconductor memory device formation space, and this may contribute to the size reduction.

According to the semiconductor memory device of the embodiment, it is possible to provide a semiconductor memory device that may be reduced in size.

Second Embodiment

Here, descriptions of the same elements as those in the first embodiment are not repeated.

FIGS. 5A to 5Care schematic views of a semiconductor memory device110of the embodiment.

A WL136is provided above the bit line wiring BL110, and extends parallel to the second side4b, in the first region4above the bit line wiring BL110. The memory cells MC are further provided between the bit line wiring BL110and the word line wiring WL136.

A word line multiplexer WL1_MUX42is provided in a seventh region40adjacent to the fifth region30in the y direction. The word line wiring WL136is connected to the word line multiplexer WL1_MUX42by a fourth connection wiring44.

The embodiment describes the arrangement of multiplexers in a case where a memory cell array MCA of the semiconductor memory device110further includes the word line wiring WL1.

According to the semiconductor memory device of the embodiment as well, it is possible to provide a semiconductor memory device that may be reduced in size.

Third Embodiment

Here, descriptions of the same elements as those in the first embodiment and the second embodiment are not repeated.

FIGS. 6A to 6Care schematic views of a semiconductor memory device120of the embodiment.

In the semiconductor memory device120, an eighth region60where another memory cell array MCA is provided is present. The eighth region60is a region that is adjacent to the first region4in the y direction such that the fifth region30is interposed therebetween. Specifically, the eighth region60is a rectangular region that has a fourth side60a, a fifth side60b, and a sixth side60cfacing the fifth side60b, in a plane parallel to the surface of the substrate2. InFIGS. 6A to 6C, the eighth region60is illustrated as a rectangular region, but is not limited to the rectangular shape. The fourth side60ais parallel to the x direction, and the fifth side60band the sixth side60care parallel to the y direction.

A BL062extends parallel to the fourth side60a, in the eighth region60above the substrate2. A word line wiring WL064extends parallel to the fifth side60b, in the eighth region above the bit line wiring BL062. A bit line wiring BL166extends parallel to the fourth side60a, in the eighth region60above the word line wiring WL064. The memory cells MC are provided between the bit line wiring BL062and the word line wiring WL064, and between the word line wiring WL064and the bit line wiring BL166, respectively.

A bit line multiplexer BL0_MUX70is provided in a ninth region68along the fifth side60b, in the eighth region60between the substrate2and the BL062.

A sixth connection wiring72is provided between the bit line multiplexer BL0_MUX70and the bit line wiring BL062to connect the bit line multiplexer BL0_MUX70to the bit line wiring BL062. The number of the sixth connection wirings72corresponds to the number of connections between the bit line multiplexer BL0_MUX70and the bit line wiring BL062, but illustration thereof is omitted inFIG. 6B.

A bit line multiplexer BL1_MUX76(is provided in a tenth region74adjacent to the ninth region68in the x direction, outside the eighth region60.

A seventh connection wiring78is provided between the bit line multiplexer BL1_MUX76and the bit line wiring BL166to connect the bit line multiplexer BL1_MUX76to the bit line wiring BL166. The number of the seventh connection wirings78corresponds to the number of connections between the bit line multiplexer BL1_MUX76and the bit line wiring BL166although that is not illustrated inFIG. 6B.

A word line multiplexer WL0_MUX_182(an example of the eighth multiplexer) is provided in an eleventh region80along the fourth side60abetween the sixth side60cand the ninth region68, in the eighth region60between the substrate2and the bit line wiring BL062.

A word line multiplexer WL0_MUX_284(an example of the ninth multiplexer) is provided outside the first region4and the eighth region60.

For example, the word line multiplexer WL0_MUX_284is provided in a twelfth region86that is adjacent to the tenth region74in the y direction outside the first region and the eighth region60. That is, the word line multiplexer WL0_MUX_284is provided between, for example, the bit line multiplexer BL1_MUX18and the bit line multiplexer BL1_MUX74.

Then, for example, as illustrated inFIG. 6C, the word line multiplexer WL0_MUX_182is connected to a part of the word line wiring WL064by, for example, an eighth connection wiring86aprovided in a thirteenth region88between the fifth region30and the eleventh region80, and the wiring31provided in the substrate2. The word line multiplexer WL0_MUX_284is connected to a part of the word line wiring WL064by, for example, an eighth connection wiring86bprovided in the thirteenth region88.

The third embodiment is an embodiment where memory cell arrays MCAs are arranged in the y direction. In this case, it is desirable that the word line multiplexers WL0_MUX_2are provided to be adjacent to each other like word line multiplexer WL0_MUX_234and word line multiplexer WL0_MUX_286. This is because the fifth region30and the thirteenth region88which are adjacent to each other are integrated, so that it is possible to effectively utilize these regions in arrangement of wirings or the like, and this contributes to the size reduction.

FIG. 7is a schematic view of a semiconductor memory device130according to another aspect of the embodiment.

In the semiconductor memory device120illustrated inFIG. 6A, the width of the word line multiplexer WL0_MUX_234in the y direction is wider than the width of the fifth region30in the y direction. However, as in the semiconductor memory device130, the width of the word line multiplexer WL0_MUX_234in the y direction may be the same as the width of the fifth region30in the y direction. In addition, the width of the word line multiplexer WL0_MUX_234in the y direction may be narrower than the width of the fifth region30in the y direction.

In the semiconductor memory device120illustrated inFIG. 6A, the width of the word line multiplexer WL0_MUX_2in the y direction is wider than the width of the thirteenth region88. However, as in the semiconductor memory device130, the width of the word line multiplexer WL0_MUX_284in the y direction may be the same as the width of the thirteenth region88in the y direction. In addition, the width of the word line multiplexer WL0_MUX_284in the y direction may be narrower than the width of the thirteenth region88in the y direction.

Furthermore, as in the semiconductor memory device130, the fifth region30and the thirteenth region88may be close to each other or in contact with each other in the y direction.

According to the semiconductor memory device of the embodiment as well, it is possible to provide a semiconductor memory device that may be reduced in size.