Method and apparatus for improving yield in semiconductor devices by guaranteeing health of redundancy information

A method for writing to memory, the method comprising:

• (a) reading a set of memory cells associated with a group of memory cells in a primary memory, the set of memory cells indicating whether data can be reliably stored in the group of memory cells in the primary memory;
• (b) if the set of memory cells indicates that data can be reliably stored in the group of memory cells in the primary memory, storing data in the group of memory cells in the primary memory;
• and
• (c) if the set of memory cells does not indicate that data can be reliably stored in the group of memory cells in the primary memory, storing data in a redundant memory.

A method for providing memory redundancy in a memory device, the method comprising:

• (a) attempting to program a set of memory cells in a redundant memory area;
• (b) attempting to program a set of memory cells in a main memory area associated with the redundant memory area;
• and
• (c) if the set of memory cells in the main memory area are not programmed successfully:
• (c1) determining whether the set of memory cells in the redundant area were programmed successfully;
• and
• (c2) if the set of memory cells in the redundant area were programmed successfully, allocate the redundant area for the main memory area.