Eddy current sensor and polishing method and apparatus

摘要

An eddy current sensor is used for detecting a metal film (or conductive film) formed on a surface of a substrate such as a semiconductor wafer. The eddy current sensor includes a sensor coil disposed near a metal film or a conductive film formed on a substrate, and the sensor coil includes a detection coil operable to detect an eddy current produced in the metal film or the conductive film. The detection coil includes a coil formed by winding a wire by a single row and plural layers, the row being defined as a direction perpendicular to the substrate and the layer being defined as a direction parallel to the substrate.