JP2001325797A - Non-volatile semiconductor storage - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce influence of a capacity coupling noise between adjacent bit lines. SOLUTION: A non-volatile semiconductor storage is provided with charging transistors for red-out (Q02, Q12,...) giving the prescribed read-out potential to a bit line to read out data, and discharging transistors for read-out (Q01, Q11,...) making a non-selection bit line a ground potential at the time of read-out, these transistors are controlled by different control signals obtained by detecting transition of an address corresponding to an inputted address every other bit line, and the non-selection bit line is set to a ground potential during read-out from before read-out of data keeping on-state of the discharging transistor for read-out.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a rewritable nonvolatile semiconductor memory device.

[0002]

2. Description of the Related Art As a rewritable non-volatile semiconductor memory device, an EEPRO which is electrically rewritable has been conventionally used.
M is known. In particular, a NAND cell type EEPROM in which a plurality of memory cells are connected in series to form a NAND cell block has been attracting attention as being capable of high integration. One memory cell of the NAND cell type EEPROM has a FETMOS structure in which a floating gate and a control gate are stacked on a semiconductor substrate via an insulating film, and a plurality of memory cells adjacent to each other have a source and a drain. They are connected in series in a shared manner to form a NAND cell.
Such NAND cells are arranged in a matrix to form a memory cell array. The drains on one end side of the NAND cells arranged in the column direction of the memory cell array are commonly connected to a bit line via a selection gate transistor, and the other end side source is also connected to a common source line via a selection gate transistor. . The control gate of the memory transistor and the gate electrode of the select gate transistor are commonly connected as a control gate line (word line) and a select gate line in the row direction of the memory cell array, respectively.

The operation of this NAND cell type EEPROM is as follows.

[0004] Data writing is performed sequentially from the memory cell farthest from the bit line. Explaining the case of the n-channel, a high potential (for example, 20 V) is applied to the control gate of the selected memory cell, and the control gate of the unselected memory cell and the gate of the selection gate transistor on the bit line side from this. Is applied with an intermediate potential (for example, 10 V). 0 V (for example, “1”) or an intermediate potential (for example, “0”) is applied to the bit line according to data. At this time, the potential of the bit line is transmitted to the drain of the selected memory cell through the selected gate transistor and the unselected memory cell.

When there is data to be written (when data is "1"), a high electric field is applied between the gate and drain of the selected memory cell, and electrons are tunnel-injected from the substrate into the floating gate. As a result, the threshold value of the selected memory cell moves in the positive direction. When there is no data to be written (when data is "0"), there is no change in the threshold value.

In data erasing, a high potential is applied to a p-type substrate (n-type substrate and p-type well formed in the case of a well structure), and the control gates of all memory cells and the gates of select gate transistors are set. 0V. Thereby, in all the memory cells, the electrons of the floating gate are emitted to the substrate, and the threshold value moves in the negative direction.

In data reading, a selected gate transistor and a non-selected memory cell are turned on, and 0 V is applied to the gate of the selected memory cell. At this time, by reading the current flowing through the bit line, "0" or "1" is determined.

Such a conventional NAND cell type EEPRO
In M, data reading or writing is usually performed simultaneously for all bit lines. Therefore, the highly integrated EE
In the PROM, capacitance coupling noise between adjacent bit lines becomes a problem.

For example, a 4 Mbit NAND cell type EEP
In the case of a ROM, a bit line formed of an Al film has a line width of 1 μm and a line interval of 1.2 μm. As a result, 1
Of the bit line capacitance of approximately 0.5 pF, approximately 50% of 0.25 pF is the capacitance between adjacent bit lines.

Therefore, for example, when the bit line is set to Vcc = 5
After pre-charging to V
When data is simultaneously read out to all bit lines, if the bit line that wants to maintain 5 V is sandwiched from both sides by the bit line that is going to discharge from 5 V to 0 V, the bit line that wants to maintain 5 V is connected by capacitive coupling. About (1/2) Vcc =
It will be reduced to 2.5V. For this reason, there is no margin for the circuit threshold value for the “0” or “1” determination of the sense amplifier, which causes a read malfunction.

The same applies to data writing. As described above, the bit line connected to the memory cell in which data is not written (that is, "0" data is written) is set to the intermediate potential VH and then floated, and the bit line connected to the memory cell to which "1" data is to be written is set. 0 V is applied to the connected bit line. Therefore, when a non-selected bit line to which writing is not performed is sandwiched by a bit line to which "1" data is to be written, the intermediate potential of the non-selected bit line to hold the intermediate potential is reduced by capacitive coupling. This causes erroneous writing to a memory cell connected to an unselected bit line, and even if erroneous writing does not occur, the threshold value of the memory cell changes and reliability is reduced.

[0012] The coupling capacitance noise between the bit lines as described above is not limited to the NAND cell type EEPROM but also to the NOR type EEPROM.
The same applies to EPROMs, and UV-erasing EPs
There is also in ROM. In addition, the problem becomes greater as the degree of integration increases.

[0013]

As described above, the conventional E
In EPROMs, EPROMs, and the like, coupling capacitance noise between bit lines has become a major problem in terms of characteristics as the degree of integration increases.

An object of the present invention is to provide a nonvolatile semiconductor memory device in which the influence of the coupling capacitance between bit lines is reduced. Is to provide.

[0015]

According to a nonvolatile semiconductor memory device of the present invention, a predetermined non-selected bit line is controlled in advance by a control signal obtained by detecting an input address on each bit line. Precharge means for fixing to a potential is provided.

According to the present invention, the non-selected bit lines sandwiching the selected bit line selected by the address are set to the ground potential in advance, for example, at the time of data reading by the precharge means provided on the bit line. That is, before the word line rises, a predetermined non-selected bit line is caused to transition to 0 V according to the result of address detection. This prevents the potential of the selected bit line sandwiched between the data lines from being lowered due to capacitive coupling during data reading, thereby preventing erroneous reading.

In the data write cycle, all the bit lines including the unselected bit lines are previously charged to a predetermined boosted potential (intermediate potential between the power supply potential and the high potential used for writing). , The selected bit line to be written is discharged. At this time, in the present invention, the charging circuit of the non-selected bit line adjacent to the selected bit line selected by the address is kept on.
As described above, during the data writing, if the charging circuit is operated without setting the non-selected bit line to be held at the intermediate potential in a floating state, the capacity of the non-selected bit line due to the transition of the bit lines on both sides to 0V The potential drop due to the coupling noise is prevented, and erroneous writing does not occur.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the illustrated embodiments.

FIGS. 1 and 2 show the configuration of a core circuit section of an EEPROM according to an embodiment of the present invention.

A plurality of bit lines BL (BL0, BL1,.
, BLn) and a plurality of word lines WL (WL0, WL1).
,..., WLm) are arranged so as to intersect with each other, and the memory cells MCij (i = 0, 1,..., J = 0, 1,.
n) are arranged to form a memory cell array. The memory cell MCij is, for example, a FETMOS-type electrically rewritable nonvolatile semiconductor memory cell in which a floating gate and a control gate are stacked, and the control gate is connected to a word line WL and the drain is connected to a bit line BL.
It is connected to the.

At one end of each bit line BL, a flip-flop type sense amplifier S / A (S / A0, S / A1,..., S / An) for reading and writing data is provided. The node of the sense amplifier S / A is connected to data input / output lines I / O and I / OB via transfer gates controlled by column selection signals CSL (CSL0, CSL1,..., CSLn). The data input / output lines I / O and I / OB are connected to an external data input / output terminal via a data input buffer and a data output buffer.

As a means for precharging the bit line BL to a predetermined potential for data reading, read charging transistors Q02, Q22,..., Q12, Q32,.
Discharge transistors Q01 and Q for reading which are transistors
, Q11, Q31,... Are provided.

The read charge transistors Q02, Q22,
, Q12, Q32,... Are for applying a read potential VR (for example, an external power supply potential) to the bit line BL in advance, and even-numbered bit lines BL1 and BL
, Provided on the odd-numbered bit lines BL0, BL2,..., Are simultaneously controlled by the control signal PREA.
Q22,... Are simultaneously controlled by another control signal PREB. The control signals PREA and PREB are
It is obtained by detecting the transition of the input address,
This is a signal for controlling the potential of the bit line BL depending on whether the address selects an odd-numbered or even-numbered bit line BL.

The read discharge transistors Q01, Q21,
, Q11, Q31,... Are used to set the unselected bit lines to the ground potential in advance, and these transistors Q1 to Q3 are provided on the even-numbered bit lines BL1, BL3,.
Are controlled simultaneously by a control signal SETA, and transistors Q01, Q21,... Provided on odd-numbered bit lines BL0, BL2,... Are simultaneously controlled by another control signal SETA. Has become. These control signals SETA and SETB are also signals for controlling the potential of the bit line BL according to whether the address selects an odd-numbered or even-numbered bit line BL.

The bit line potential control circuit for writing data is not shown in FIGS. 1 and 2. This part will be described later.

The data reading operation of the EEPROM having the above-described structure will be described below.

FIGS. 3 and 4 are the first half and the second half of a timing chart showing a read cycle. Of these, FIG. 3 in the first half shows a state in which odd-numbered bit lines are selected, and FIG. 4 in the second half shows a state in which even-numbered bit lines are selected.

In the initial state, the control signals PREA,
PREB are both at the "H" level of Vcc, so that the charge transistors Q02, Q22,..., Q12, Q32,... The control signals SETA and SETB are both at Vcc, so that the read discharge transistors Q01 and Q
, Q11, Q31,... Are all on, and all bit lines BL are at source power supply potential Vss (normal ground potential).
Is set to

The chip enable / CE changes from "H" level to "L" level, and a row address and a column address are fetched from outside the chip. Inside the chip, an address transition detection circuit operates to generate a row address transition detection pulse and a column address transition detection pulse.

As described above, the address transition detection circuit operates,
When the odd-numbered bit line is selected by the fetched row address, among the control signals SETA, SETB, SETA changes from Vcc to Vss, thereby providing the odd-numbered bit lines BL0, BL2,. The read discharge transistors Q01, Q21,... Are turned off. At the same time, of the control signals PREA and PREB,
ss, whereby the odd-numbered bit lines BL0, BL
Read charge transistors Q12, Q provided in
Are turned on, and the odd-numbered bit lines BL0, B
Are precharged to the read potential VR. The even-numbered bit lines BL1, BL3,... Are kept at Vss because the discharging transistors Q11, Q31,.

Thus, the odd-numbered bit lines BL0, B
When the word line WL0 selected by the row address changes from Vss to Vcc after L2,... Are precharged to the read potential VR, the odd-numbered bit lines BL0, BL2,.
Cell MC00, along the word line WL0 connected to
Data is read only from MC02,..., MC0n-1. The memory cells MC0 connected to the even-numbered unselected bit lines BL1, BL3,... Driven by the same word line WL0
1, MC03,..., MC0n are not selected bit line B
Since L1, BL3,... Are fixed to Vss in advance, they are not read. This is because a memory cell is a non-destructive read-type nonvolatile semiconductor memory unlike a DRAM or the like.

The data read to the odd-numbered bit lines BL0, BL2,...
, S / A2,... Then, one column selection signal CSL0 selected by the column address becomes "H".
As a result, the data latched in the sense amplifier S / A0 is output to the outside via the input / output lines I / O and I / OB and the output buffer. When the column address changes and the column address transition detection circuit detects this and the next column selection line CSL2 goes to "H" level, the data latched by the sense amplifier S / A2 is output. Hereinafter, the column continuous reading for the odd-numbered bit lines is similarly performed. So far,
This is shown in FIG.

Further, when the row address changes, the row address transition detection circuit detects this and generates an address transition detection pulse. Then, the process is performed again from the selection of the even-numbered bit line or the odd-numbered bit line. FIG. 4 shows a case where an even-numbered bit line is selected. At this time, odd-numbered bit lines B
L0, BL2,... Are fixed at Vss, and the data of the memory cells of the even-numbered bit lines BL1, BL3,. FIG. 4 shows a case where the word line WL0 is also selected at this time. At this time, the memory cells MC01, MC
03,... Are even-numbered bit lines BL1, BL3,.
... is read. When the column selection signal CSL1 goes to "H" level, the sense amplifier S / A1
Then, the row address changes and the column selection signal CSL3 goes to "H" level, whereby the data of the sense amplifier S / A3 is output. Similarly, in this case as well, continuous column reading is performed for even-numbered bit lines.

As described above, in this embodiment, when the even-numbered bit line is selected according to the address, the odd-numbered unselected bit line is set to Vss before the word line is selectively driven. I have. Similarly, when the odd-numbered bit line is selected, the even-numbered bit line is set to Vss in advance as a non-selected bit line. Therefore, as in the prior art, the non-selected bit line transitions from the precharge potential Vcc to 0 V at the time of data reading, so that the precharge potential of the selected bit line sandwiched therebetween does not decrease due to capacitive coupling. Malfunction is reliably prevented.

FIGS. 5 and 6 show the configuration of a core circuit section of an EEPROM according to another embodiment of the present invention. In this embodiment, the odd-numbered bit lines BL0A, BL1A,.
nA and even-numbered bit lines BL0B, BL1B,.
Are paired with each other, and each pair shares the sense amplifiers S / A0, S / A1,..., S / An. The configurations of the memory cells MCijA, MCijB and the cell array are the same as in the previous embodiment. Similarly to the previous embodiment, read discharge transistors Q01A, Q01A, which are controlled by different control signals SETA, SETB for odd-numbered and even-numbered bits, respectively, are provided in each bit line.
11A, ..., Qn1A and Q01B, Q11B, ..., Qn1B.

The end of each bit line BL on the sense amplifier side is
Selection gate transistors Q03A, Q13A, ..., Qn3A and Q03B, Q13B,
~, Qn3B via the sense amplifier S /
A0, S / A1, ..., S / An. Select gate transistors Q03A, Q13A, ..., Qn3A and Q03
B, Q13B,..., Qn3B are controlled by different control signals SELA, SELB determined by addresses. At the position where the bit lines are grouped two by two, PM
Readout charging transistor Q0 which is an OS transistor
2, Q12,..., Qn2 are provided.

FIGS. 7 and 8 show the EEP of this embodiment.
FIG. 4 is an operation timing chart of a read cycle of a ROM.

In the initial state, the control signal PRE of the charging transistor is at the "H" level of Vcc, the control signals SELA and SELB of the selection gate are at the "L" level of Vss, and the control signals SETA and SETB of the discharging transistor are at the level of Vcc. This is at the “H” level, and all the bit lines BL are set to the source power supply potential Vss (normally the ground potential) as in the previous embodiment.

The chip enable / CE changes from "H" level to "L" level, and a row address and a column address are fetched from outside the chip. Inside the chip, an address transition detection circuit operates to generate a row address transition detection pulse and a column address transition detection pulse.

As described above, the address transition detection circuit operates,
When the odd-numbered bit line is selected by the fetched row address, among the control signals SETA and SETB, SETA changes from Vcc to Vss, whereby the odd-numbered bit lines BL0A, BL1A,. The read discharge transistors Q01, Q21,... At the same time, the control signal PRE becomes Vss, and among the control signals SELA and SELB of the selection gate, SELA becomes "H" level. Thereby, the odd-numbered bit line B
.. Provided in L0A, BL1A,... Are turned on, and the odd-numbered bit lines BL0A, BL1A,. The even-numbered bit lines BL0B, BL1B,.
Is kept.

Thus, the odd-numbered bit lines BL0A and BLO
When the word line WL0 selected by the row address changes from Vss to Vcc after L1A,... Are precharged to the read potential VR, the odd-numbered bit lines BL0A, BL1A,.
Cell MC00A along word line WL0 connected to
, MC01A,..., MC0nA are read out.
The memory cells M connected to the even-numbered unselected bit lines BL0B, BL1B,... Driven by the same word line WL0
The data of C00B, MC01B,..., MC0nB is not read.

Data read to the odd-numbered bit lines BL0A, BL1A,...
, S / A1,... When the column selection signal CSL0 goes to "H" level, the data latched by the sense amplifier S / A0 is output to the input / output line I / A.
It is output externally via output buffers via O and I / OB. The column address changes, and the column address transition detection circuit detects this and detects the next column selection line CSL1.
Becomes "H" level, the data latched by the sense amplifier S / A1 is output. Thereafter, in the same manner as in the previous embodiment, the column continuous reading for the odd-numbered bit lines is performed.

When the row address further changes, the row address transition detection circuit detects this and generates a pulse. Then, the process is performed again from the selection of the even-numbered bit line or the odd-numbered bit line. FIG. 8 shows a case where even-numbered bit lines are selected. At this time, odd bit lines BL0A, BL1A,.
ss, and the even-numbered bit lines BL0B, BL1B,.
Is read out from the memory cell of. At this time, if WL0 is selected as the selected word line, the memory cell M
The data of C00B, MC01B, ... is an even-numbered bit line B
Are read out as L0B, BL1B,. Thereafter, when the column selection signal CSL0 goes to "H" level, the data of the sense amplifier S / A0 is output. Similarly,
Also in this case, continuous column reading can be performed on even-numbered bit lines.

FIGS. 9 and 10 show an embodiment in which a circuit necessary for writing data is added to the EEPROM of the embodiment shown in FIGS. In this embodiment in addition to the embodiments of FIGS. 5 and 6, NMO is applied to each bit line BL.
Write transistor Q04A which is an S transistor
, ..., Qn4A and Q04B, ..., Qn4B. These write charge transistors Q04A,.
Qn4A and Q04B,..., Qn4B apply a potential VH (preferably an intermediate potential between the high potential Vpp applied to the word line WL at the time of writing) and the power supply potential Vcc to the bit line BL. It is for. The transistors Q04A,..., Qn4A provided on the odd-numbered bit lines are simultaneously controlled by the control signal WSEA, and the transistors Q04B,. Is controlled by

The write control signals WSEA and WSEB control the write charge transistors Q04A,..., Qn4A and Q04B,..., Qn4B, respectively, so that all the bit lines are sent before the write data is sent from the sense amplifier to the bit lines. It is precharged to the intermediate potential VH, the selected bit line (for example, odd-numbered bit line) is made floating during data writing, and the intermediate potential VH is continuously applied to the non-selected bit lines (for example, even-numbered bit line). Perform control.

FIGS. 11 and 12 show the E of this embodiment.
The first half and the second half of the timing diagram of the data write cycle of the EPROM. Using this, a specific write operation will be described.

The chip enable / CE and the write enable / WE change from "H" level to "L" level, and the write operation is started. First, data is written from the input / output buffer to the sense amplifiers S / A0, S / A1,..., S / An via the input / output lines I / O and I / OB. This is because the column selection signals CSL0, CSL1,... Sequentially become "H" level in accordance with the column address as shown in FIG. 11, so that the serial data is sequentially written to the sense amplifier in synchronization with this. . n
If there are +1 sense amplifiers, this is repeated until data is written to the nth sense amplifier.

During the data writing to the sense amplifier,
Both the write control signals WSEA and WSEB are changed from Vss to VH.
+ Α (α is the write charge transistor Q04A,.
Qn4A and Q04B,..., Qn4B), and all bit lines BL are precharged to the intermediate potential VH.

Then, the last n-th sense amplifier S /
After the data is written to An, one of the write control signals WSEA and WSEB becomes Vss according to the row address. In FIG. 12, the odd-numbered bit lines BL0A,
, BLnA is written, and in this case, the control signal WSEA becomes Vss. As a result, the write charge transistors Q04A,..., Qn4A of the odd-numbered bit lines BL0A,. Thereby, the odd-numbered bit line B is changed according to the data previously transmitted to the sense amplifiers S / A0,..., S / An.
L0A,..., BLnA become Vss (for "1" data) or VH (for "0" data).

Thereafter, the selected word line WL0 is set at Vss.
From the bit line BL to the odd-numbered bit line BL
Electrons are injected into the floating gate in the memory cell connected to the bit line of Vss among 0A,..., BLnA.
This is data "1" writing. During this time, the even-numbered bit lines BL0B,..., BLnB are all fixed at the intermediate potential VH, not floating, because the charging transistors Q04B,.

When data is written to the even-numbered bit lines BL0B,..., BLnB, on the contrary, all the non-selected odd-numbered bit lines BL0A,. Is done.

As described above, in this embodiment, every other unselected bit line is fixed at the intermediate potential VH during the write operation. Therefore, as in the prior art, it is precharged to the intermediate potential in advance, but becomes floating during the write operation, and the potential of the bit line sandwiched between the bit lines of “1” data write transitioning to Vss is reduced by capacitive coupling. Will not be.

Next, the present invention is applied to a NAND cell type EEPROM.
An embodiment applied to (1) will be described.

FIGS. 13 to 15 show a core circuit portion of the NAND cell type EEPROM of the embodiment. FIG. 13 shows an end structure on the opposite side of the sense amplifier, and FIG. 14 shows a cell array structure. Reference numeral 15 denotes the configuration of the sense amplifier side end.

As shown in FIG. 14, for example, FETMOS
A plurality of memory cells (eight in the figure) are connected in series in such a manner that adjacent memory cells share a source and a drain with each other to form a NAND cell. The drain end of the NAND cell is connected to the bit line BL via a select gate controlled by select gate lines SGD0, SGD1,. The source end of the NAND cell is also connected to the select gate line SGS0.
, SGS1,... Are connected to a common source line via select gates. The control gates of the memory cells arranged in a direction intersecting with the bit line BL are commonly connected to each other to form a word line WL.

As shown in FIG. 13, the discharge transistors Q01A,..., Qn1A for reading are provided at the end of the bit line opposite to the sense amplifier in the cell array, as shown in FIG.
, Qn1B, and write transistors Q04A,..., Qn4A, Q04B,.

As shown in FIG. 15, select bit transistors Q03A,..., Qn3A, Q03B, Q03B, as shown in FIG.
, Qn3B, and two reading transistors Q02,..., Qn2 are provided here.

The sense amplifiers S / A0,..., S / An
As also shown in FIG.
It is composed of flip-flops combined with inverters.

FIGS. 16 to 19 show the NAN of this embodiment.
FIG. 3 is a timing chart of a read cycle of a D-cell EEPROM. 16 and 17 show the first half of the read cycle, and FIGS. 18 and 19 show the second half. In order to make the timing easy to understand, chip enable / C
E, row address and column address signal waveforms are shown. The read operation will be described below with reference to this timing chart.

When the chip enable / CE changes from "H" level to "L" level and a row address and a column address are fetched from the outside into the chip, an address transition detection circuit operates inside the chip, as shown in FIG. As shown, a row address transition detection pulse and a column address transition detection pulse are generated.

When reading the data of the memory cells connected to the odd-numbered bit lines BL0A,..., BLnA based on the fetched row address, the even-numbered bit lines BL0B, BL0B,.
, BLnB are kept at the ground potential Vss during the read operation. That is, the control signal SET is set according to the row address.
Of A and SETB, SETA changes from Vcc to Vss,
Thereby, the read discharge transistors Q01A,..., Qn1 provided on the odd-numbered bit lines BL0A,.
A turns off. At the same time, the control signal PRE becomes Vss, and the control signals SELA and SELB of the bit line selection gate are controlled.
Among them, SELA becomes "H" level. As a result, the select gate transistors Q03A,..., Qn3A provided on the odd-numbered bit lines BL0A,..., BLnA are turned on, and the odd-numbered bit lines BL0A,. Even-numbered bit line BL
0B,..., BLnB are kept at Vss.

The sense amplifiers S / A 0,..., S / An
Before the data of the memory cell is read out to the bit line, it is made inactive. This corresponds to the control signal S of the sense amplifier.
EN, RLCH is changed from Vcc to Vss, and control signals SENB,
This is performed by changing RLCHB from Vss to Vcc.
After the odd-numbered bit lines BL0A,..., BLnA are precharged to the read potential VR, the control signal SEN is temporarily changed from Vss to Vcc, then to Vss again to initialize the sense amplifier, and the control signal RLCHB is reset. May be changed from Vcc to Vss and Vcc in synchronization with this.

Next, the non-selected word lines determined by the row address, WL01 to WL07 in the figure and the selection gate lines SGS0 and SGD0 are changed from Vss to Vcc, and the selected word line WL00 is maintained at Vss. The threshold voltage of the memory cell is set to, for example, 0.5 V or more and 3.5 V or less for “1” data, and −0.1 V or less for “0” data. Then, the selected word line WL
00 is set to Vss = 0 V, and the non-selected word lines WL01 to WL07 and the selection gate lines SGS0, SGD0 are set to Vcc = 5V, so that the memory cells MC00 along the selected word line WL00 are set.
A, MC00B,..., MC0nA, MC0nB, the memory cells MC connected to the odd-numbered bit lines BL0A,.
The data of 00A, ..., MC0nA is read. Since the even-numbered unselected bit lines BL0B,..., BLnB are fixed at Vss, the data of the memory cells MC00B,..., MConB at the intersection of these selected word lines WL00 is not read.

Thus, the odd-numbered bit lines BL0A,.
The data read to BLnA is the sense amplifier S / A0
,..., S / An are activated, that is, the control signals SEN and RLCH become Vcc, SENB and RLCH.
When B becomes Vss, the sense amplifier S /
A0,..., Are latched by S / An.

When the column selection signal CSL0 goes to "H" level, the data latched in the sense amplifier S / A0 is sent to the outside via the input / output lines I / O and I / OB and the output buffer. Is output. When the column address changes and the column address transition detection circuit detects this and the next column selection line CSL1 goes to "H" level, the data latched by the sense amplifier S / A1 is output. Thereafter, in the same manner as in the previous embodiment, the column continuous reading for the odd-numbered bit lines is performed.

When the row address further changes, the row address transition detection circuit detects this and generates a pulse. Then, the process is performed again from the selection of the even-numbered bit line or the odd-numbered bit line. FIGS. 18 and 19 show the case where the even-numbered bit line is selected. In this case, odd-numbered bit lines BL0A,.
Are fixed to Vss, and even-numbered bit lines BL
Data of memory cells 0B,..., BLnB are read.
At this time, if WL00 is selected as the selected word line, the data of the memory cells MC00B,..., MC0nB is read out to the even-numbered bit lines BL0B,. Thereafter, when the column selection signal CSL0 goes to "H" level, the data of the sense amplifier S / A0 is output.
Similarly, in this case as well, continuous column reading can be performed on even-numbered bit lines.

During the above read operation, the "H" level potential BITH and the "L" level potential BI of the sense amplifier are set.
TL may be Vcc and Vss, respectively.

Next, a data write operation in this embodiment will be described with reference to FIGS. 20 and 21 show the first half of the write cycle, and FIGS. 22 and 23 show the second half. Chip enable / CE,
The write enable / WE, input data Din, row address, and column address are shown in all figures to make the timing easy to understand.

The chip enable / CE and the write enable / WE change from "H" level to "L" level, and the write operation is started. First, data is written from the input / output buffer to the sense amplifiers S / A0,..., S / An via the input / output lines I / O and I / OB. This depends on the column address as shown in FIG.
When the column selection signals CSL0, CSL1,... Sequentially become "H" level, serial data is sequentially written to the sense amplifier in synchronization with this. If there are (n + 1) sense amplifiers, this is repeated until data is written to the nth sense amplifier.

During data writing to this sense amplifier,
The write control signals WSELA and WSELB both change from Vss to VH + α, and all bit lines BL are precharged to an intermediate potential VH higher than Vcc.

After the data is written to the last n-th sense amplifier S / An, one of the write control signals WSELA and WSELB becomes Vss according to the row address. In FIG. 22, odd bit lines BL0A,.
This shows a case where data is written to LnA, in which case the control signal WSELA becomes Vss. As a result, the write / charge transistors Q04A,..., Qn4A of the odd-numbered bit lines BL0A,. Thereby, according to the data previously transmitted to the sense amplifiers S / A0,..., S / An, the odd-numbered bit lines BL0A, BL0A,.
, BLnA are Vss (in the case of "1" data) or VH
(In the case of "0" data).

Thereafter, the selected word line WL00 is set at Vss.
From the word line WL01 to the write potential Vpp.
WL07 and the select gate line SGD0 on the drain side are connected to Vss.
From VH to α. Odd-numbered bit lines BL0A,.
In the memory cell connected to the bit line of Vss of BLnA, electron injection ("1" writing) is performed on the floating gate. Meanwhile, the even-numbered bit lines BL0B,.
Are fixed at the intermediate potential VH instead of floating because the charging transistors Q04B,..., Qn4B are kept on.

When data is to be written to even-numbered bit lines BL0B,..., BLnB, conversely, unselected odd-numbered bit lines BL0A,. Will be done.

During the above-mentioned data write operation, the low potential side BITL of the sense amplifier may be Vss.

In the above embodiment, the electrically rewritable EEPROM has been exclusively described.
The present invention is also effective for ROM.

[0076]

As described above in detail, according to the present invention, the effect of capacitive coupling noise between adjacent bit lines at the time of data reading or writing is greatly reduced, and a highly reliable nonvolatile semiconductor memory device is provided. Obtainable.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a part of a core circuit of an EEPROM according to an embodiment of the present invention.

FIG. 2 is a diagram showing the configuration of the rest of the core circuit.

FIG. 3 is a timing chart showing the first half of a read cycle of the EEPROM of the embodiment.

FIG. 4 is a timing chart showing the latter half of the read cycle;

FIG. 5 is a diagram showing a configuration of a part of a core circuit of an EEPROM according to another embodiment.

FIG. 6 is a diagram showing the configuration of the rest of the core circuit.

FIG. 7 is a timing chart showing the first half of the read cycle of the EEPROM of the embodiment.

FIG. 8 is a timing chart showing the latter half of the read cycle.

FIG. 9 is a diagram showing a partial configuration of a core circuit according to an embodiment in which a data write control circuit is added to the EEPROM of FIGS. 5 and 6;

FIG. 10 is a view showing the configuration of the rest of the core circuit.

FIG. 11 is a timing chart showing the first half of a write cycle according to the first embodiment;

FIG. 12 is a timing chart showing the latter half of the write cycle.

FIG. 13 is a diagram showing a configuration of a part of a core circuit of an EEPROM according to still another embodiment.

FIG. 14 is a diagram showing a configuration of a cell array unit of the core circuit.

FIG. 15 is a diagram showing the configuration of the rest of the core circuit.

FIG. 16 is a timing chart showing the first half of the read cycle of the EEPROM of the embodiment.

FIG. 17 is a timing chart showing the first half of the read cycle.

FIG. 18 is a timing chart showing the latter half of the read cycle of the EEPROM of the embodiment.

FIG. 19 is a timing chart showing the latter half of the read cycle.

FIG. 20 is a timing chart showing the first half of the write cycle of the EEPROM of the embodiment.

FIG. 21 is a timing chart showing the first half of a write cycle.

FIG. 22 is a timing chart showing the latter half of the write cycle of the EEPROM of the embodiment.

FIG. 23 is a timing chart showing the latter half of the write cycle.

[Explanation of symbols]

MC: Memory cell BL: Bit line WL: Word line S / A: Sense amplifier Q01, Q21, ..., Q (n-1) 1, Q11, Q31, ..., Qn1 ... Read discharge transistor Q02, Q22, ..., Q (n-1) 2, Q12, Q32, ..., Qn2 ... Reading charge transistors Q04A, Q04B, ..., Qn4A, Qn4B ... Write charge transistors

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masaki Mochitomi 1 Toshiba R & D Co., Ltd., Komukai-ku, Kawasaki-shi, Kanagawa Pref. No. 1 town Toshiba Research Institute, Inc. (72) Inventor Fujio Masuoka No. 1, Komukai Toshiba Town, Koyuki-ku, Kawasaki-shi, Kanagawa Prefecture Toshiba Research Institute, Inc. F-term (reference) 5B025 AA03 AB01 AC01 AD04 AD06 AD11 AE08

Claims (12)

[Claims] 1. A plurality of bit lines, a plurality of word lines intersecting the bit lines, and a plurality of word lines arranged at respective intersections of the bit lines and the word lines and driven by the word lines. A rewritable nonvolatile semiconductor memory cell that exchanges data with a bit line, and detects data of a memory cell provided by one or two of the bit lines and selected by the word line. A sense amplifier, a precharge having a read charge transistor connected to the bit line for applying a predetermined read potential to the bit line for data read, and a read discharge transistor for setting a non-selected bit line to the ground potential at the time of read Means, and wherein the read charge transistor and the read discharge transistor are connected to the address corresponding to the address input at the start of the read operation. Every other bit line is controlled by a different control signal obtained by detecting an address, so that all of one of the odd-numbered bit lines and the even-numbered bit lines are selected bit lines, and all of the other ones are all selected bit lines. It becomes an unselected bit line, the selected bit line becomes a floating state after pre-charging, the selected bit line is connected to the sense amplifier, and is arranged at each intersection of a selected word line and the selected bit line. A nonvolatile semiconductor memory device, wherein data of all memory cells are simultaneously read out to the sense amplifier. 2. In a data read cycle, data read to an odd-numbered bit line or an even-numbered bit line as the selected bit line is simultaneously detected by the sense amplifier, and latched by the sense amplifier. 2. The nonvolatile semiconductor memory device according to claim 1, wherein the read data is continuously read in correspondence with a column address. 3. The non-volatile memory according to claim 1, wherein the odd-numbered bit lines and the even-numbered bit lines are paired in pairs, and each pair shares a sense amplifier. Semiconductor memory device. 4. The non-volatile semiconductor memory device according to claim 3, wherein said read charge transistor is provided at a position where bit lines are arranged two by two. 5. The nonvolatile semiconductor memory cell is an electrically rewritable nonvolatile semiconductor memory cell, wherein a plurality of the nonvolatile semiconductor memory cells are connected to form a cell block. The nonvolatile semiconductor memory device according to claim 1 . 6. The nonvolatile semiconductor memory device according to claim 5 , wherein said cell block is a NAND cell formed by connecting a plurality of electrically rewritable nonvolatile semiconductor memory cells in series. 7. A plurality of bit lines, a plurality of word lines arranged to intersect with the bit lines, and a plurality of bit lines arranged at respective intersections of the bit lines and the word lines and driven by the word lines. A rewritable nonvolatile semiconductor memory cell in which data is exchanged with a bit line; a sense amplifier provided for every two bit lines and detecting data of a memory cell selected by the word line; A precharge means connected to the bit line, for applying a predetermined read potential to a selected bit line for data read, and for holding an unselected bit line at a predetermined fixed potential; A first memory cell group and an even memory cell arranged at each intersection position between all the odd-numbered bit lines and the word line among the memory cells arranged at each intersection position between a line and a plurality of the bit lines. Th second data of the memory cell group arranged at each intersection position between the word lines and all the bit lines, the nonvolatile semiconductor memory device, wherein the read out to the sense amplifier at the same time, respectively. 8. A plurality of bit lines, a plurality of word lines intersecting the bit lines, and a plurality of bit lines arranged at respective intersections of the bit lines and the word lines and driven by the word lines. A rewritable nonvolatile semiconductor memory cell for exchanging data with a bit line; and a sense amplifier connected to the bit line, wherein each intersection of a selected word line and the bit line is provided. A first memory cell group arranged at each intersection of the word line with all of the odd-numbered bit lines or all of the even-numbered bit lines selected by the address among the memory cells arranged at the positions; And the second memory cell group are simultaneously written with the data taken in the sense amplifier, and the other is intermediate between a power supply voltage and a high potential used for writing. The nonvolatile semiconductor memory device characterized by holding the boosted potential is position. 9. A plurality of bit lines, a plurality of word lines intersecting the bit lines, and a plurality of word lines arranged at respective intersections of the bit lines and the word lines and driven by the word lines. A rewritable nonvolatile semiconductor memory cell that exchanges data with a bit line, and detects data of a memory cell provided by one or two of the bit lines and selected by the word line. A sense amplifier, and a precharge means connected to the bit line for applying a predetermined read potential to a selected bit line for data reading and holding an unselected bit line at a predetermined fixed potential. Of all the odd-numbered bit lines or all of the even-numbered bit lines selected by the address among the memory cells arranged at the respective intersections of the selected word line and the bit line. Non-volatile semiconductor memory device wherein data of one of a first memory cell group and a second memory cell group arranged at each intersection with a read line is simultaneously read out to the sense amplifier. . 10. A serial data read for successively reading data read by said sense amplifier corresponding to a column address is performed for each of a first memory cell group and a second memory cell group. 10. The nonvolatile semiconductor memory device according to claim 9, wherein: 11. A plurality of bit lines, a plurality of word lines intersecting the bit lines, and a plurality of word lines arranged at respective intersections of the bit lines and the word lines and driven by the word lines. A rewritable nonvolatile semiconductor memory cell in which data is exchanged with a bit line, a sense amplifier connected to the bit line, and a bit line connected to the bit line, and the bit line is connected at the time of a data write cycle. A non-volatile semiconductor memory device, comprising: a transistor that charges to a predetermined potential; and all of the unselected bit lines are fixed at a predetermined potential during a write operation. 12. Precharge all bit lines to a predetermined potential before write data is sent from the sense amplifier to the bit lines, set a selected bit line to a floating state during data writing, and set a predetermined bit line to an unselected bit line. 12. The nonvolatile semiconductor memory device according to claim 11, wherein a potential is continuously applied.