Semiconductor memory device and operating method thereof

A semiconductor memory device, comprising:

• a memory cell array including a plurality of memory cells which are programmed to a plurality of program states;
• a peripheral circuit configured to perform a program operation on the memory cell array;
• and
• a control logic configured to control the peripheral circuit to group the plurality of program states into a first program group and a second program group, and perform a program operation on the first program group and then perform a program operation on the second program group during the program operation,
• wherein the control logic groups program states, which have low threshold voltage distributions and are adjacent to one another, among the plurality of program states into the first program group, and groups program states, which have relatively higher threshold voltage distributions than the low threshold voltage distributions and are adjacent to one another, among the plurality of program states into the second program group.

A method of operating a semiconductor memory device, the method comprising:

• receiving a plurality of data to be programmed from the outside the semiconductor device, and storing the received data in a read and write circuit connected with bit lines of a memory cell array;
• grouping the plurality of data into a plurality of program groups;
• performing a program operation on a selected program group among the plurality of program groups;
• and
• when a program operation for the selected program group is completed, performing a program operation on a next program group,
• wherein the grouping of the plurality of data into the plurality of program groups includes grouping the plurality of data into the plurality of program groups according to a plurality of program states corresponding to the plurality of data and grouping the program states having threshold voltage distributions adjacent to one another into one program group.