Lithography measurement machine and operating method thereof

A lithography measurement machine, comprising:

• a rotating base configured to place a first mask, a second mask, a third mask and a fourth mask, wherein each of the first mask, the second mask, the third mask and the fourth mask has a first exposure unit, a second exposure unit, a third exposure unit and a fourth exposure unit, and the first mask, the second mask, the third mask and the fourth mask are staggered such that the first exposure unit of the first mask, the second exposure unit of the second mask, the third exposure unit of the third mask and the fourth exposure unit of the fourth mask are arranged adjacently to form an exposure area, the first exposure unit is adjacent to the second exposure unit, the first exposure unit and the second exposure unit are disposed along a first direction, the fourth exposure unit is adjacent to the first exposure unit, the fourth exposure unit and the first exposure unit are disposed along a second direction, and the first direction is perpendicular to the second direction;
• an image simulation unit configured to simulate a first coordinate information according to the exposure area, wherein the first coordinate information has a first center;
• a scanning electron microscope (SEM) configured to scan the exposure area to obtain a second coordinate information, wherein the second coordinate information has a second center;
• and
• a processor electrically connected with the image simulation unit and the scanning electron microscope, wherein the processor is configured to compare the first coordination information with the second coordinate information.