Semiconductor inspection tool and methods of operation

A method, comprising:

• receiving a semiconductor workpiece on a stage of a semiconductor inspection tool;
• performing an inspection operation to inspect the semiconductor workpiece using the semiconductor inspection tool;
• and
• monitoring, using a monitoring system mounted to the semiconductor inspection tool a distance between the semiconductor workpiece and a bottom lens of the semiconductor inspection tool in association with the inspection operation,
• wherein monitoring the distance between the semiconductor workpiece and the bottom lens comprises:
• rotating a monitoring device of the monitoring system around the bottom lens to monitor the distance between the semiconductor workpiece and the bottom lens.

A semiconductor inspection tool, comprising:

• an inspection device comprising a bottom lens;
• and
• a lens monitoring system comprising:
• a support member coupled with the inspection device;
• a monitoring device coupled with the support member;
• an annular ring around the inspection device;
• and
• a base plate around the annular ring,
• wherein the support member is attached to the base plate,
• wherein the annular ring is fixed to the inspection device, and
• wherein the base plate is configured to rotate relative to the annular ring.