Method and apparatus of arrayed, clustered or coupled eddy current sensor configuration for measuring conductive film properties

A system for processing a wafer, comprising:

• a chemical mechanical planarization (CMP) tool, the CMP tool including,
• a wafer carrier defined within a housing, the wafer carrier having a bottom surface having a window defined therein;
• a carrier film affixed to the bottom surface of the wafer carrier, the carrier film configured to support a wafer during CMP operations;
• and
• a sensor embedded in the wafer the sensor disposed over a top surface of the window, the sensor configured to induce an eddy current in the wafer to determine a proximity and a thickness of the wafer;
• a sensor array external to the CMP tool, the sensor array in communication with the sensor embedded in the wafer carrier, the sensor array including a first sensor and a corresponding second sensor, the first sensor and the corresponding second sensor configured to alternate between an active state and a passive state, the first sensor further configured to be in an active state when the second sensor is in a passive state, the sensor array configured to detect a wafer thickness signal that is independent of a distance of the first sensor and the corresponding second sensor to the wafer.