Fuse concept and method of operation
AssigneeInfineon Technologies North America Corp.
InventorsHans Viehmann, Heinz Hoenigschmid
Life of this patent
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Abstract
It is difficult to fabricate a semiconductor memory device without any faulty memory storage cells. One solution is to produce more storage cells than needed on a device and faulty storage cells are replaced by the redundant storage cells. This solution requires that the addresses of the faulty storage cells, along with the replacement storage cells, be saved in a memory. The present invention teaches the use of non-volatile memory cells, particularly magnetoresistive random access memory (MRAM) cells, to store the addresses. Non-volatile memory cells can effectively replace the laser fuses currently used and also provides an advantage in the elimination of the laser fuse-burning step during the fabrication of the device.
Claims30
A semiconductor memory device comprising:
- a first memory for storing logical data values in storage cells;
- an address decoder coupled to the first memory, the address decoder containing circuitry to decode address bits provided to the memory device and to select a storage cell;
- a redundant controller coupled to the address decoder, the redundant controller comprising a second memory for storing a list of addresses of faulty memory storage cells and a redundant memory storage cell for each faulty memory storage cell, wherein the second memory comprising nonvolatile, resistive memory cells;
- a redundant address decoder coupled to the redundant controller, the redundant address decoder containing circuitry to decode the address bits of the replacement memory storage cells to select a redundant memory storage cell in the redundant memory;
- and
- a redundant memory coupled to the redundant address decoder, the redundant memory containing redundant memory storage cells.
The semiconductor memory device of claim 17, wherein the bridge configuration comprises four individual MRAM cells.
A method for providing fault tolerance in a semiconductor memory device comprising:
- testing memory storage cells for faults;
- determining faulty memory storage cells;
- saving faulty memory storage cells to non-volatile memory;
- and
- associating redundant memory storage cells to the faulty memory storage cells.
Dependencies are inferred from the claim text.