Chemical mechanical polishing apparatus and method

A chemical mechanical polishing apparatus, comprising:

• a polishing pad having a polishing surface;
• a polishing head configured to hold a wafer in contact with the polishing surface;
• a pad conditioner configured to move between a conditioning position over the polishing surface and a home position away from the polishing pad rather than over the polishing surface, wherein the pad conditioner is operable to apply a downward force according to a predetermined downward force stored in a controller to condition the polishing surface at the conditioning position, and move from the conditioning position to the home position after conditioning the polishing surface;
• a measurement tool disposed relative to the pad conditioner at the home position and separated from the pad conditioner, wherein the measurement tool is configured to measure the downward force actually applied by the pad conditioner to the measurement tool after conditioning the polishing surface;
• and
• the controller coupled to the pad conditioner and the measurement tool, and configured to compare the downward force measured by the measurement tool and the predetermined downward force, and calibrate the downward force actually applied by the pad conditioner when a difference between the downward force measured by the measurement tool and the predetermined downward force exceeds a range of acceptable values.

A chemical mechanical polishing apparatus, comprising:

• a processing chamber;
• a polishing pad provided in the processing chamber and having a polishing surface;
• a pad conditioner configured to move between a conditioning position over the polishing surface and a home position away from the polishing pad rather than over the polishing surface, wherein the pad conditioner is operable to apply a downward force according to a predetermined downward force stored in a controller to condition the polishing surface at the conditioning position, and move from the conditioning position to the home position after conditioning the polishing surface;
• a measurement tool provided separately in the processing chamber and disposed relative to the pad conditioner at the home position, wherein the measurement tool is configured to measure the downward force actually applied by the pad conditioner to the measurement tool after conditioning the polishing surface, wherein the measurement tool comprises:
• a frame, wherein an outer surface of the frame is coated with a protection layer to protect the frame from an environment in the processing chamber;
• and
• a pressure transducer received in the frame, configured to measure the downward force actually applied by the pad conditioner to the measurement tool;
• and
• the controller coupled to the pad conditioner and the measurement tool, and configured to compare the downward force measured by the measurement tool and the predetermined downward force, and calibrate the downward force actually applied by the pad conditioner when a difference between the downward force measured by the pressure transducer and the predetermined downward force exceeds a range of acceptable values.