A memory system includes a plurality of memory cells, and the memory cells are multiple-level cells. The memory system performs program operations to program the memory cells. After each program operation, at least one threshold voltage test is performed to determine if threshold voltages of the memory cells are greater than the verification voltage. When the threshold voltage of a first memory cell is determined to be greater than a first verification voltage, the first memory cell will be inhibited from being programmed during the next program operation. When the threshold voltage of a second memory cell is determined to newly become greater than a second verification voltage, where the second verification voltage is greater than the first verification voltage, the second memory cell will be programmed again during the next program operation.

According to one embodiment, a semiconductor memory device comprises a first memory cell array including a first block and a second block, the first block including a first memory cell, and the second block including a second memory cell; and a controller that performs, in a first period of time in writing, a first program in the first memory cell and the second memory cell.

A series of programming pulses, where the individual pulses are identified by a pulse number, is used to program a page of memory cells in parallel. After receiving a pulse, the memory cells under verification are verified to determine if they have been programmed to their respective target states. The memory cells that have been verified are inhibited from further programming while those memory cells not verified will be further programmed by subsequent programming pulses. The pulsing, verification and inhibition continue until all memory cells of the page have been program-verified. Each verify level used in the verification is a function of both the target state and the pulse number. This allows adjustment of the verify level to compensate for changes in sensing, including those due to variation in source line loading during the course of programming.

A processing device determines a plurality of computing error metrics that are indicative of operational characteristics between programming distributions within the memory device. The processing device performs a program targeting operation on a memory cell of the memory device to calibrate one or more program verify (PV) targets associated with the programming distributions. Performing the program targeting operation comprises the processing device selecting a rule from a predefined set of rules based on the plurality of computing error metrics, wherein the predefined set of rules corresponds to an adjusting of a PV target of a last programming distribution. In addition, the processing device adjusts, based on the selected rule, the one or more PV targets of a plurality of PV targets associated with the programming distributions, wherein the one or more PV targets correspond to one or more respective voltage values for programming memory cells of the memory device.

During a phase of programming the cell, a first voltage is applied to the source region and a second voltage, higher than the first voltage, is applied to the drain region until the cell is put into conduction. The numerical value of the item of data to be written is controlled by the level of the control voltage applied to the control gate and the item of data is de facto written with the numerical value during the putting into conduction of the cell. The programming is then stopped.

During a phase of programming the cell, a first voltage is applied to the source region and a second voltage, higher than the first voltage, is applied to the drain region until the cell is put into conduction. The numerical value of the item of data to be written is controlled by the level of the control voltage applied to the control gate and the item of data is de facto written with the numerical value during the putting into conduction of the cell. The programming is then stopped.

During a phase of programming the cell, a first voltage is applied to the source region and a second voltage, higher than the first voltage, is applied to the drain region until the cell is put into conduction. The numerical value of the item of data to be written is controlled by the level of the control voltage applied to the control gate and the item of data is de facto written with the numerical value during the putting into conduction of the cell. The programming is then stopped.

A series of programming pulses, where the individual pulses are identified by a pulse number, is used to program a page of memory cells in parallel. After receiving a pulse, the memory cells under verification are verified to determine if they have been programmed to their respective target states. The memory cells that have been verified are inhibited from further programming while those memory cells not verified will be further programmed by subsequent programming pulses. The pulsing, verification and inhibition continue until all memory cells of the page have been program-verified. Each verify level used in the verification is a function of both the target state and the pulse number. This allows adjustment of the verify level to compensate for changes in sensing, including those due to variation in source line loading during the course of programming.

A method of programming a memory system includes: reading a target page included in a selected memory block in response to a program request when at least one of the pages included in the selected memory block contains data; and performing a program for the target page when, among the data bits included in the data read from the target page, the number of data bits having a first logic value is equal to or less than a preset value.

A processing device determines a plurality of computing error metrics that are indicative of operational characteristics between programming distributions within the memory device. The processing device performs a program targeting operation on a memory cell of the memory device to calibrate one or more program verify (PV) targets associated with the programming distributions. Performing the program targeting operation comprises the processing device selecting a rule from a predefined set of rules based on the plurality of computing error metrics, wherein the predefined set of rules corresponds to an adjusting of a PV target of a last programming distribution. In addition, the processing device adjusts, based on the selected rule, the one or more PV targets of a plurality of PV targets associated with the programming distributions, wherein the one or more PV targets correspond to one or more respective voltage values for programming memory cells of the memory device.