Patent ID: 11915770
Assignee: SAMSUNG ELECTRONICS CO., LTD.
Field: Computer technology (Electrical engineering)
Classification: CPC G  H | IPC G  H

Claim 19:
20. A method of testing a nonvolatile memory device that includes a plurality of memory cells connected to a plurality of wordlines, the method comprising:
providing the nonvolatile memory device in which initial data is stored in the plurality of memory cells connected to the plurality of wordlines, the initial data having an initial threshold voltage distribution that includes only a first state;
before a solder reflow process is performed on the nonvolatile memory device, performing a first write operation such that first data is stored into memory cells connected to first wordlines from among the plurality of wordlines, the solder reflow process being a manufacturing process in which thermal stress is applied to the nonvolatile memory device, the first data having a first threshold voltage distribution that is different from the initial threshold voltage distribution and includes a plurality of states, the first wordlines having a degree of reliability degradation less than a reference value among the plurality of wordlines;
performing a first test operation on the nonvolatile memory device;
before the solder reflow process is performed on the nonvolatile memory device, performing a second write operation such that second data is stored into memory cells connected to second wordlines from among the plurality of wordlines, the second data having a second threshold voltage distribution that is different from the first threshold voltage distribution and includes only a second state, the second wordlines having a degree of reliability degradation greater than or equal to the reference value among the plurality of wordlines;
performing the solder reflow process on the nonvolatile memory device; and
performing a second test operation on the nonvolatile memory device,
wherein each of the first state and the second state are included in the plurality of states,
wherein the second data is more robust against reliability degradation than the first data, and
wherein the first test operation is performed before the second write operation or after the second write operation.