Kioxia Corporation

Yoshiki Takai

Masahiro Saito

Kiwamu Watanabe

Yuko Noda

Tsukasa Tokutomi

A memory system includes a non-volatile memory including a plurality of memory cells; and a controller. The controller is configured to perform a multi-step write operation to write multi-bit data with respect to each of target memory cells through a first programming to set a first threshold voltage and then a second programming to set a second threshold voltage. The controller, during the multi-step write operation, determines a time period elapsed from a first time at which the first programming with respect to a first memory cell of the target memory cells has been performed, and varies a second time at which the second programming with respect to the first memory cell is performed based on whether the time period is greater than a first threshold.

Memory system performing multi-step write operation and control method thereof

A memory controller receives first, second, and third data by first, second, and third reads, specifying a first address, and respectively specifying first, second, and third read voltages higher in this order. The controller instructs a memory to execute a fourth read specifying a fourth read voltage lower than the first read voltage and the first address when a first difference between a first-value-bit count of the first data and an expected value is smaller than a second difference between a first-value-bit count of the third data and the expected value. The memory controller instructs the memory to execute a fifth read specifying a fifth read voltage higher than the third read voltage and the first address when the first difference is larger than the second difference.

Growing community of inventors

Fujisawa Kanagawa, Japan

Yoshiki Takai