Method and apparatus for redundancy word line replacement in a semiconductor memory device
First Claim
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1. A semiconductor memory device, comprising:
- memory cells arranged in rows and columns, said memory cells including normal memory cells and redundant memory cells for replacing defective ones of said normal memory cells;
bit line pairs connected to said memory cells, each bit line pair consisting of first and second bit lines which are respectively connected to memory cells for storing true data and memory cells for storing complementary data in corresponding ones of said columns;
word lines, said word lines including normal word lines each respectively connected to normal memory cells in a corresponding one of said rows and redundant word lines each respectively connected to redundant memory cells in a corresponding one of said rows, said normal word lines including a first normal word line for selecting a first normal memory cell for storing true data connected to the first bit line of one of said bit line pairs and a second normal word line for selecting a second normal memory cell for storing complementary data connected to the second bit line of said one of said bit line pairs, and said redundant word lines including a first redundant word line for selecting a first redundant memory cell for storing true data connected to the first bit line of said one of said bit line pairs and a second redundant word line for selecting a second redundant memory cell for storing complementary data connected to the second bit line of said one of said bit line pairs;
a data line pair consisting of first and second data lines for inputting/outputting complementary data signals to/from said bit line pairs;
a data flip circuit for selectively flipping the data signals on said first and second data lines; and
redundancy control means for controlling said data flip circuit to flip the data signals on said first and second data lines when said first normal memory cell connected to said first normal word line is replaced with said second redundant memory cell connected to said second redundant word line or when said second normal memory cell connected to said second normal word line is replaced with said first redundant memory cell connected to said first redundant word line.
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Abstract
A method and apparatus for redundancy word line replacement in a semiconductor device involves generating a control signal which causes the data on the data lines to be flipped when the bit pattern of the memory cells coupled to a redundant word line are complementary to the bit pattern of the memory cells of a defective word line which is being replaced by the redundant word line. During both read and write operations, a data flip control signal is input to a data flip circuit to control the state of the bit information.
129 Citations
32 Claims
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1. A semiconductor memory device, comprising:
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memory cells arranged in rows and columns, said memory cells including normal memory cells and redundant memory cells for replacing defective ones of said normal memory cells; bit line pairs connected to said memory cells, each bit line pair consisting of first and second bit lines which are respectively connected to memory cells for storing true data and memory cells for storing complementary data in corresponding ones of said columns; word lines, said word lines including normal word lines each respectively connected to normal memory cells in a corresponding one of said rows and redundant word lines each respectively connected to redundant memory cells in a corresponding one of said rows, said normal word lines including a first normal word line for selecting a first normal memory cell for storing true data connected to the first bit line of one of said bit line pairs and a second normal word line for selecting a second normal memory cell for storing complementary data connected to the second bit line of said one of said bit line pairs, and said redundant word lines including a first redundant word line for selecting a first redundant memory cell for storing true data connected to the first bit line of said one of said bit line pairs and a second redundant word line for selecting a second redundant memory cell for storing complementary data connected to the second bit line of said one of said bit line pairs; a data line pair consisting of first and second data lines for inputting/outputting complementary data signals to/from said bit line pairs; a data flip circuit for selectively flipping the data signals on said first and second data lines; and redundancy control means for controlling said data flip circuit to flip the data signals on said first and second data lines when said first normal memory cell connected to said first normal word line is replaced with said second redundant memory cell connected to said second redundant word line or when said second normal memory cell connected to said second normal word line is replaced with said first redundant memory cell connected to said first redundant word line. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A semiconductor memory device, comprising:
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a plurality of normal and redundant memory cells connected to word lines and bit lines, a first group of said word lines coupled to normal and redundant memory cells having a first bit pattern and a second group of said word lines coupled to normal and redundant memory cells having a second bit pattern different from said first bit pattern; first and second data lines, said first data line being coupled to a first group of bit lines and said second data line being coupled to a second group of said bit lines; a data flip circuit for flipping data signals on said first and second data lines when a normal memory cell coupled to said second group of word lines is coupled to said data lines and when a redundant memory cell coupled to said second group of word lines is coupled to said data lines. - View Dependent Claims (11, 12, 13, 14)
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15. A method for testing a semiconductor memory device comprising the steps of:
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inputting identical data signals to true bit pattern memory cells and complementary bit pattern memory cells; accessing the data signals from the true bit pattern memory cells and the complementary bit pattern memory cells; flipping the data signals accessed from the complementary bit pattern memory cells; and determining whether the flipped data signals and the data signals accessed from the true bit pattern memory cells are the same, wherein if the flipped data signals and the data signals accessed from the true bit pattern memory cells are not the same a defective memory cell has been detected.
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16. A semiconductor memory device with row redundancy comprising:
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bit line pairs each consisting of a first bit line and a second bit line; a first normal word line for selecting a first normal memory cell for storing true data connected to said first bit line of one of said bit line pairs; a second normal word line for selecting a second normal memory cell for storing complementary data connected to said second bit line of said one of said bit line pairs; a first redundant word line for selecting a first redundant memory cell for storing true data connected to said first bit line of said one of said bit line pairs; a second redundant word line for selecting a second redundant memory cell for storing complementary data connected to said second bit line of said one of said bit line pairs; a data line pair consisting of a first data line and a second data line, said data line pair transferring data signals to/from one of said normal memory cells or one of said redundant memory cells via said first and second bit lines; a data flip circuit for selectively flipping the data signals on said first and second data lines; and redundancy control means for controlling said data flip circuit to flip the data signals on said first and second data lines when said first normal memory cell connected to said first normal word line is replaced with said second redundant memory cell connected to said second redundant word line or when said second normal memory cell connected to said second normal word line is replaced with said first redundant memory cell connected to said first redundant word line. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24)
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25. A semiconductor memory device with row redundancy comprising:
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a plurality of first memory cells for storing true data, said first memory cells being connected to a first group of word lines; a plurality of second memory cells for storing complementary data, said second memory cells being connected to a second group of word lines; a first group of bit lines connected to said first and second memory cells and arranged to cross said first and second groups of word lines; a second group of bit lines connected to said first and second memory cells and arranged to cross said first and second groups of word lines and arranged between said first group of bit lines; and a data line pair comprising a first data line connected to said first group of bit lines and a second data line connected to said second group of bit lines; a data flip circuit inhibited from flipping bit information on said first and second data lines when said first memory cells are connected to said first and second data lines, said data flip circuit flipping the bit information on said first and second data lines when said second memory cells are connected to said first and second data lines. - View Dependent Claims (26, 27, 28, 29)
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30. A method for testing a semiconductor memory device with row redundancy, having memory cells arranged in rows and columns, the memory cells connected to bit lines and including normal memory cells and redundant memory cells wherein the normal memory cells are connected to normal word lines and the redundant memory cells are connected to redundant word lines, said method comprising the steps of:
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detecting a defective memory cell in a normal memory cell array; inhibiting a normal word line connected to said detected defective memory cell from being accessed, and replacing said defective memory cell with a redundant memory cell connected to a redundant word line; determining whether an input row address is identical to a stored row address, the stored address indicating the normal word line connected to said defective memory cell; determining whether data stored in a memory cell to be accessed by the input row address is identical to data stored in a replaced normal memory cell when the input row address is identical to the stored row address; flipping data in order to write the data in said redundant memory cell when the input row address is different from the stored row address; reading the data written in said redundant memory cell to flip the data; and determining whether the data written in said redundant memory cell is identical to the data read from said redundant memory cell, wherein if said data written in and read from said redundant memory cell is not identical then said redundant memory cell is defective.
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31. A semiconductor memory device comprising:
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a first word line connected to a first row of memory cells each of which stores data in a true data state; a second word line connected to a second row of memory cells each of which stores data in a complementary data state; a first bit line connected to a memory cell in said first row of memory cells; a second bit line connected to a memory cell in said second row of memory cells; and data flipping means for flipping data signals supplied to/from said first and second bit lines when one of said first and second word lines replaces the other of said first and second word lines. - View Dependent Claims (32)
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Specification