Method of detecting over-programming in a solid-state drive

A method of detecting an over-programming of a memory cell having a plurality of states during a write operation in a NAND-based memory media of a solid-state drive, the method comprising:

• checking a current first bit of a current state of a plurality of states of the memory cell for a current programming condition;
• checking a current last bit of the memory cell to detect an over-programming condition of the current state in which the current last bit overlaps a next state of the plurality of states of the memory cell, wherein an over-programming verification level used to check the current last bit of the memory cell to detect the over-programming condition of the current state is between zero (0) millivolts and one hundred fifty (150) millivolts lower than a regular programming verification level used to check a next first bit of the next state of the plurality of states of the memory cell;
• performing a read operation to read data from the plurality of states of the memory cell;
• and
• based on the detecting of the over-programming condition, adjusting the read operation for the over-programmed current last bit to compensate for the over-programming condition.

A solid-state drive with over-programming detection of a memory cell during a write operation in a non-volatile memory media, the solid-state drive comprising:

• the non-volatile memory media configured to store data;
• and
• a controller configured to perform a plurality of functions including—
• checking a current first bit of a current state of a plurality of states of the memory cell for a current programming condition,
• checking a current last bit of the memory cell to detect an over-programming condition of the current state in which the current last bit overlaps a next state of the plurality of states of the memory cell, and
• based on the detection of the over-programming condition, performing one of the two following operations—
• (a) identifying the over-programmed current last bit, recording an address and a bit location for the over-programmed current last bit and recording a temperature for the program operation at which the over-programming condition occurred, and adjusting the program operation to use a smaller program pulse voltage step size for a subsequent program operation involving the memory cell, or
• (b) retiring a memory block in which the over-programmed current last bit is located.

A method of detecting an over-programming of a memory cell during a write operation in a non-volatile memory media of a solid-state drive, the method comprising:

• performing a program operation to write data to a plurality of states of the memory cell;
• checking a current first bit of a current state of the plurality of states of the memory cell for a current programming condition;
• checking a current last bit of the memory cell to detect an over-programming condition of the current state in which the current last bit overlaps a next state of the plurality of states of the memory cell, wherein an over-programming verification level for the current last bit of the memory cell to detect the over-programming condition of the current state is lower than a regular programming verification level for a next first bit of the next state of the plurality of states of the memory cell, and wherein the over-programming verification level is between one (1) and one hundred fifty (150) millivolts lower than the regular programming verification level used to check the next first bit of the next state of the plurality of states of the memory cell;
• and
• based on the detection of the over-programming condition, performing one of the two (2) following operations—
• (a) identifying the over-programmed current last bit and adjusting the program operation to use a smaller program pulse voltage step size for a subsequent program operation involving the memory cell, or
• (b) retiring a memory block in which the over-programmed current last bit is located.

A solid-state drive with over-programming detection of a memory cell during a write operation in a non-volatile memory media, the solid-state drive comprising:

• the non-volatile memory media configured to store data;
• and
• a controller configured to perform a plurality of functions including—
• checking a current first bit of a current state of a plurality of states of the memory cell for a current programming condition,
• checking a current last bit of the memory cell to detect an over-programming condition of the current state in which the current last bit overlaps a next state of the plurality of states of the memory cell, wherein an over-programming verification level for the current last bit of the memory cell to detect the over-programming condition of the current state is lower than a regular programming verification level for a next first bit of the next state of the plurality of states of the memory cell, and wherein the over-programming verification level is between one (1) and one hundred fifty (150) millivolts lower than the regular programming verification level used to check the next first bit of the next state of the plurality of states of the memory cell, and
• based on the detection of the over-programming condition, performing one of the two following operations—
• (a) identifying the over-programmed current last bit and adjusting the program operation to use a smaller program pulse voltage step size for a subsequent program operation involving the memory cell, or
• (b) retiring a memory block in which the over-programmed current last bit is located.