System and method for characterization of thin films

A method for use in characterizing a sample comprising a thin film, the method comprising:

• providing calibration information representative of surface spectrum measurements for thin films of a plurality of samples correlated with depth profile information for the thin films of the plurality of samples, wherein each of the plurality of samples is formed under a same set of process conditions, and further wherein providing the calibration information comprises:
• providing surface spectrum measurements for the thin film of each of the plurality of samples using a particular set of parameters, wherein providing the surface spectrum measurements comprises:
• irradiating the sample with x-rays resulting in the escape of photoelectrons therefrom;
• detecting photoelectrons escaping from the sample;
• and
• generating a signal representative of the detected photoelectrons,
• wherein the surface spectrum measurements are based on the generated signals;
• and
• providing depth profile information for the thin film of each of the plurality of samples, wherein providing the depth profile information comprises collecting depth profile data at each of a plurality of depths of the sample, each depth corresponding to a sample surface, wherein one or more of the plurality of depths of the sample are provided by removing material from the sample during material removal intervals resulting in sample surfaces at the one or more depths of the sample, and further wherein collecting depth profile data at each of the plurality of depths of the sample comprises:
• irradiating the sample with x-rays resulting in the escape of photoelectrons therefrom;
• detecting photoelectrons escaping from the sample;
• and
• generating a signal representative of the detected photoelectrons;
• and
• using the depth profile data collected for at least a first and second depth to generate at least a portion of the depth profile information, wherein the second depth is at a position deeper in the sample than the first depth;
• performing one or more surface spectrum measurements for a thin film of a sample to be characterized using the particular set of parameters, the thin film formed under the same set of process conditions as the thin films of the plurality of samples;
• and
• determining at least one characteristic of the thin film of the sample to be characterized based on the one or more surface spectrum measurements of the sample to be characterized and the calibration information.

A system for use in characterizing a sample, wherein the system comprises:

• an x-ray source operable to irradiate a sample with x-rays when the sample is positioned at an analysis plane of the system resulting in the escape of photoelectrons therefrom;
• an analyzer operable to detect photoelectrons escaping from the sample, wherein the analyzer is operable to generate a signal representative of the detected photoelectrons;
• an ion source operable to provide ions for removal of material from a sample positioned at the analysis plane during material removal intervals resulting in sample surfaces at one or more depths of the sample;
• and
• a computing apparatus operable to:
• recognize calibration information representative of surface spectrum measurements for a plurality of samples correlated with depth profile information for the plurality of samples, wherein each of the plurality of samples is formed under a same set of process conditions, and further wherein the depth profile information is provided using surface spectrum measurements performed at one or more progressively deeper depths of each of the plurality of samples, the one or more progressively deeper depths resulting from the removal of material from the sample;
• generate one or more surface spectrum measurements for a sample to be characterized based on a signal representative of detected photoelectrons;
• and
• determine at least one characteristic of the sample based on the one or more surface spectrum measurements for the sample to be characterized and the calibration information.