Polishing device using eddy current sensor

A method of detecting the thickness of any one of first and second films formed on a substrate, said method comprising:

• supplying a sensor coil with any one of a first alternating current having a first frequency when detecting the first film and a second alternating current having a second frequency when detecting the second film, for generating an eddy current in any one of the first film and the second film;
• measuring an impedance across the sensor coil;
• dividing the impedance into resistance and reactance components;
• and
• detecting the thickness of any one of the first film and the second film based on the resistance component of the impedance.

A method of detecting the thickness of any one of first and second films formed on a substrate, said method comprising:

• supplying a sensor coil with any one of a first alternating current having a first frequency when detecting the first film and a second alternating current having a second frequency when detecting the second film, for generating an eddy current in any one of the first film and the second film;
• detecting a signal from said sensor coil;
• generating an in-phase component and a quadrature component from the signal;
• extracting the in-phase component as a resistance component;
• extracting the quadrature component as a reactance component;
• and
• detecting the thickness of any one of the first film and the second film based on the resistance component.

A method of polishing a substrate, said method comprising:

• supplying a sensor coil with a first alternating current having a first frequency when polishing a first film on the substrate;
• measuring a first impedance across the sensor coil;
• detecting the thickness of the first film based on the first impedance;
• supplying a sensor coil with a second alternating current having a second frequency when polishing a second film on the substrate;
• measuring a second impedance across the sensor coil;
• and
• detecting the thickness of the second film based on the second impedance.

A method of polishing a substrate, said method comprising:

• supplying a sensor coil with a first alternating current having a first frequency when polishing a first film on the substrate;
• detecting a first signal from the sensor coil;
• generating a first in-phase component and a first quadrature component from the first signal;
• extracting the first in-phase component as a first resistance component;
• extracting the first quadrature component as a first reactance component;
• detecting the thickness of the first film based on the first resistance component;
• supplying the sensor coil with a second alternating current having a second frequency when polishing a second film on the substrate;
• detecting a second signal from the sensor coil;
• generating a second in-phase component and a second quadrature component from the second signal;
• extracting the second in-phase component as a second resistance component;
• extracting the second quadrature component as a second reactance component;
• and
• detecting the thickness of the second film based on the second resistance component.

A method of detecting a characteristic of any one of first and second films formed on a substrate, said method comprising:

• supplying a sensor coil with any one of a first alternating current having a first frequency when detecting the first film and a second alternating current having a second frequency when detecting the second film, for generating an eddy current in the first film or the second film;
• measuring an impedance across the sensor coil;
• and
• detecting the characteristic of any one of the first film and the second film based on the impedance.