Nonvolatile Memory And Writing Method Thereof, And Semiconductor Device
First Claim
1. A memory device comprising:
- a memory cell array comprising;
a plurality of first memory cells; and
at least one second memory cell; and
a circuit for writing data to the plurality of first memory cells and the second memory cell,wherein, when the writing of the data to one of the plurality of first memory cells fails, the circuit is arranged to assign an address of the one of the plurality of first memory cells to the second memory cell and write the data to the second memory cell.
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Accused Products
Abstract
A write-once memory can be written only once to each memory cell; therefore, a defective bit cannot be detected by an actual inspection of writing. Accordingly, as described above, the measures, in which a redundant circuit is provided and the defective bit is modified before shipping, cannot be taken; thus, it is difficult to provide a memory with few defects. It is an object of the present invention to provide a write-once memory where the probability of a defect is reduced considerably. A nonvolatile memory that can be written only once includes a redundant memory cell, a first circuit which allocates an address to the redundant memory cell, a second circuit which outputs a determination signal that expresses whether writing is performed normally or not, and a third circuit, to which the determination signal is inputted, which controls the first circuit and the second circuit.
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Citations
18 Claims
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1. A memory device comprising:
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a memory cell array comprising; a plurality of first memory cells; and at least one second memory cell; and a circuit for writing data to the plurality of first memory cells and the second memory cell, wherein, when the writing of the data to one of the plurality of first memory cells fails, the circuit is arranged to assign an address of the one of the plurality of first memory cells to the second memory cell and write the data to the second memory cell. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for driving a memory device, the method comprising:
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writing data to a plurality of first memory cells; confirming whether the data is normally stored in the plurality of first memory cells; and writing the data, which is attempted to be stored in one of the plurality of first memory cells, to a second memory cell if the data is not normally stored in the one of the plurality of first memory cells. - View Dependent Claims (13, 14, 15, 16, 17, 18)
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Specification