Measurement system and probe tip landing method

A measurement system including a scanning electron microscope (SEM), the SEM has an electron source, a lens system, and a detector, the measurement system comprises:

• a probe;
• a stage, configured to carry a sample;
• a motor system, configured to raise and lower the probe, wherein the motor system includes a coarse motor and a fine motor;
• and
• a processing device, configured to perform following operations:
• driving the coarse motor to perform a first descending operation to lower the probe toward a first region of the sample by a first descending distance;
• after the first descending operation, driving the fine motor to perform a second descending operation to lower the probe toward the first region of the sample;
• performing an inspection operation during the second descending operation, the inspection operation comprises:
• an imaging operation, scanning the sample to obtain a first image through the scanning electron microscope, wherein the first image includes a probe tip of the probe;
• and
• a determining operation, checking the first image to determine that in the first image, whether a region connected with the probe tip becomes brighter due to more secondary electrons generated at the region;
• and
• in response to the region connected with the probe tip in the first image becoming brighter, determining that the probe has contacted a surface of the first region of the sample and the probe has landed successfully.