Method and device for measuring the thickness of opaque and transparent films

A method for determining a property of sample that comprises a metal film using a measurement system attached to a processing tool, the method comprising the steps of:

• forming or processing the metal film in a first portion of the processing tool;
• and
• measuring the property of the metal film by:
• generating a first beam of optical radiation that impinges the sample and initiates an acoustic response;
• irradiating the sample with a second beam of radiation to generate a signal beam of radiation that is modulated by the acoustic response;
• detecting the signal beam of radiation to generate a radiation-induced electrical signal;
• processing the radiation-induced electrical signal to determine the film's thickness.

A processing tool for processing a thin film comprised by a sample, the tool comprising:

• a film-processing component in a first portion of the processing tool;
• and
• a film-measuring component attached to the processing tool, the film-measuring component comprising:
• a light source that generates an optical excitation pulse;
• an optical system aligned to receive the optical excitation pulse and focus the optical excitation pulse onto a surface of the sample initiate an acoustic response;
• a light source that generates a probe beam that irradiates the sample to generate a signal beam;
• an optical detector that detects the signal beam to generate a light-induced signal;
• and
• a processor configured to process the light-induced signal from the optical detector to determine a property of the sample.

A processing tool for processing a thin film comprised by a sample, the tool comprising:

• a film-processing component in a first portion of the processing tool;
• and
• a film-measuring component attached to the processing tool, the film-measuring component comprising:
• a light source that generates an optical excitation pulse;
• an optical system aligned to receive the optical excitation pulse, separate the optical excitation pulse into at least two optical pulses, and overlap the two optical pulses onto a surface of the sample initiate an acoustic response;
• a light source that generates a probe beam that irradiates the sample to generate a diffracted signal beam;
• an optical detector that detects the diffracted signal beam to generate a light-induced signal;
• and
• a processor configured to process the light-induced signal from the optical detector to determine a thickness of the sample.