Combination of ellipsometry and optical stress generation and detection

An apparatus having at least a first configuration used to perform ellipsometry and a second configuration used to perform optical stress generation and detection, comprising:

• an optical source configured to generate a pump beam and a probe beam, where each of the beams is directed to a surface of a sample;
• a controllable retarder placed in a path of a selected one of the pump beam or the probe beam, the controllable retarder configured to modify at least a polarization of the selected beam in response to a control signal;
• a controller configured to provide at least one control signal to the controllable retarder, wherein the controller is configured in the first configuration to cause at least one first control signal to be applied to the controllable retarder, the controller configured in the second configuration to cause at least one second control signal to be applied to the controllable retarder, wherein the at least one first control signal and the at least one second control signal are configured to cause different polarizations of the selected beam;
• a detector configured to receive a version of the selected beam reflected from the surface of the sample and to output data corresponding to the reflected version;
• and
• a data analysis module coupled to the detector and configured in the first configuration to perform data analysis using the output data in order to determine at least one first characteristic of the sample, and further configured in the second configuration to perform data analysis using the output data in order to determine at least one second characteristic of the sample.

A computer-readable medium having a program of computer-readable instructions tangibly embodied thereon, the instructions executable by a processing unit to perform operations comprising:

• selecting one of performing ellipsometry or performing optical stress generation and detection;
• in response to selecting performing ellipsometry, applying at least one first control signal configured to instruct to a controllable retarder to modify at least a polarization of a light beam directed to a surface of a sample to generate a first modified light beam, and performing ellipsometry using a first reflected version of the first modified light beam reflected from the sample in order to determine at least one first characteristic of the sample;
• and
• in response to selecting performing optical stress generation and detection, applying at least one second control signal configured to instruct to the controllable retarder to generate a second modified light beam, and performing optical stress generation and detection using a second reflected version of the second modified light beam in order to determine at least one second characteristic of the sample.