Apparatus and method for measurement of the mechanical properties and electromigration of thin films

A method for characterizing a sample, comprising the steps of:

• applying an optical pump pulse to the sample and measuring a first change ΔΦ1 in an optical phase of a subsequently applied optical pulse that is reflected from the sample;
• passing an electric current through a region of interest of the sample;
• after the passage of the electric current, applying another optical pump pulse to the sample and measuring a second change ΔΦ2 in the optical phase of another subsequently applied optical pulse that is reflected from the sample;
• determining a difference between the first change ΔΦ1 in the optical phase and the second change ΔΦ2 in the optical phase;
• and
• relating the difference to a rate of electromigration in the metal film.

A non-destructive system for characterizing a mechanical property of a film, comprising:

• a stage holding a substrate of a predetermined thickness thereon, the film being located over a surface of the substrate;
• a system for changing strain in the film from an initial
• strain value to a different strain value;
• an optical system for applying optical pump pulses and optical probe pulses to a surface of the film, individual ones of the optical probe pulses being temporally delayed from individual ones of the optical pump pulses;
• a detection system for detecting a change ΔΦ in an optical phase of reflected optical probe pulses when the film has the initial strain value and also when the film has the different strain value;
• and
• associating the determined difference with at least one mechanical property of the film.