Semiconductor device and manufacturing method of semiconductor device

A semiconductor device comprising:

• a line;
• a source structure on the line;
• a contact plug penetrating the source structure;
• a stack structure on the source structure and the contact plug, wherein a lower surface of the stack structure is in contact with an upper surface of the contact plug;
• a first slit structure penetrating the stack structure, extending in a first direction, and being adjacent to the contact plug in the first direction;
• and
• a second slit structure penetrating the stack structure and extending in the first direction, the second slit structure being adjacent to the first slit structure in a second direction intersecting the first direction and being adjacent to the contact plug in the second direction,
• wherein the first slit structure and the second slit structure are spaced apart from each other by a first distance in the second direction, the first slit structure and the contact plug are spaced apart from each other by a second distance in the first direction,
• wherein the second distance is longer than the first distance, and
• wherein a sidewall of the first slit structure and a sidewall of the contact plug face each other.