Memory device and method of operating the same

A method of operating a memory device, comprising:

• setting up a first step voltage to increase a program voltage and a second step voltage to increases pass voltages;
• performing a program loop with an operation of applying the program voltage to a selected word line and a verify operation of verifying memory cells that are coupled to the selected word line;
• increasing the program voltage by the first step voltage when a number of times a program loop is performed increases;
• and
• increasing the pass voltages that are applied to unselected word lines by the second step voltage, in order of proximity to the selected word line, as the number of times a program loop is performed increases.

A method of operating a memory device, comprising:

• increasing a program voltage that is applied to a selected word line stepwise when a number of times a program loop is performed increases;
• increasing a pass voltage that is applied to unselected word lines that are adjacent to the selected word line stepwise as the number of times a program loop is performed increases;
• and
• increasing a number of unselected word lines to which the pass voltage increased stepwise is applied as the number of times a program loop is performed increases.