Methods And Systems For Measurement Of Semiconductor Structures With Mechanical Stress Modulation

A method comprising:

• illuminating a structure fabricated on a semiconductor specimen with an illumination beam during a measurement interval;
• exciting a mechanical wave propagating through the structure during the measurement interval, wherein a mechanical stress at the structure varies with time during the measurement interval;
• detecting measurement signals associated with measurements of the structure in response to the illumination beam and the mechanical stress;
• estimating a change in values of one or more electrical or optical properties of one or more materials comprising the structure induced by the variation of the mechanical stress with time;
• estimating a change in values of the detected measurement signals induced by the variation of the mechanical stress;
• and
• estimating a value of a parameter of interest characterizing the structure under measurement based on the change in values of one or more electrical or optical properties of the one or more materials comprising the structure and the change in values of the detected measurement signals.

A metrology system comprising:

• an illumination subsystem configured to illuminate a structure fabricated on a semiconductor specimen with an illumination beam during a measurement interval;
• a mechanical wave excitation source configured to excite a mechanical wave propagating through the structure during the measurement interval, wherein a mechanical stress at the structure varies with time during the measurement interval;
• a detector configured to detect measurement signals associated with measurements of the structure in response to the illumination beam and the amount of mechanical stress;
• and
• a non-transitory, computer-readable medium storing instructions that, when executed by one or more processors, causes the one or more processors to:
• estimate a change in values of one or more electrical or optical properties of one or more materials comprising the structure induced by the variation of the mechanical stress;
• estimate a change in values of the detected measurement signals induced by the variation of the mechanical stress;
• and
• estimate a value of a parameter of interest characterizing the structure under measurement based on the change in values of one or more electrical or optical properties of the one or more materials comprising the structure and the change in values of the detected measurement signals.