Contamination monitoring and control techniques for use with an optical metrology instrument

A method of cleaning a sample from which optical data is desired to be obtained through the use of an optical metrology tool, comprising:

• directing a light beam at a discrete location of the sample so as to clean contaminates from the discrete location of the sample, wherein the light beam has wavelengths including at least in part wavelengths below DUV wavelengths;
• and
• utilizing the optical metrology tool to measure a property of the sample at the discrete location, the property obtained at least in part utilizing information related to wavelengths below DUV wavelengths, the property of the sample being independent of the contaminates,
• wherein measurement and cleaning of the same discrete location is achieved by utilizing at least a common portion of an optical module of the optical metrology tool to accomplish the cleaning and measurement with coincident light so as to minimize alignment errors between the cleaning and measurement steps.

A method of obtaining optical data from a sample through the use of an optical metrology tool, comprising:

• collecting first optical data from a first location of the sample;
• cleaning the first location of the sample through exposure to light radiation after collecting the first optical data;
• collecting second optical data from the first location of the sample after cleaning the first location of the sample, the second optical data relating to a property of the sample independent of a contaminate layer;
• and
• determining at least one property of the contaminate layer on the sample at least in part by utilizing the first optical data and the second optical data.

A method of obtaining optical data from a sample through the use of an optical metrology tool, comprising:

• collecting first optical data from the sample;
• changing a property of the sample through exposure of at least a portion of the sample to light radiation after collecting the first optical data;
• collecting second optical data from the sample after changing the property of the sample, the second optical data including optical data impacted by properties of the sample that comprise more than just contaminate layer properties of the sample;
• and
• determining at least one characteristic of the sample at least in part by utilizing the first optical data and the second optical data.