Optical method for the characterization of laterally-patterned samples in integrated circuits
AssigneeBrown University Research Foundation
InventorHumphrey J. Maris
Life of this patent
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Abstract
Disclosed is a method for characterizing a sample having a structure disposed on or within the sample, comprising the steps of applying a first pulse of light to a surface of the sample for creating a propagating strain pulse in the sample, applying a second pulse of light to the surface so that the second pulse of light interacts with the propagating strain pulse in the sample, sensing from a reflection of the second pulse a change in optical response of the sample, and relating a time of occurrence of the change in optical response to at least one dimension of the structure.
Claims30
A method for characterizing a sample having a structure disposed on or within said sample, comprising the steps of:
- applying a first pulse of light to a surface of said sample to excite said structure into a vibration in at least one normal mode of vibration of said structure;
- applying a second pulse of light to said surface;
- sensing from a reflection of said second pulse a change in a transient optical response of said sample;
- relating said change in the transient optical response to an oscillatory component of said vibration;
- and
- associating said oscillatory component to at least one of a spatial or electrical characteristic of said structure.
A method for characterizing a sample having a structure disposed on or within said sample, comprising the steps of:
- applying a first pulse of light to a surface of said sample to excite said structure into a vibration in at least one normal mode of vibration of said structure;
- applying a second pulse of light to said surface;
- sensing from a reflection of said second pulse a change in optical response of said sample;
- relating said change in optical response to an oscillatory component of said vibration;
- and
- associating said oscillatory component to at least one of a spatial or electrical characteristic of said structure, wherein said step of relating comprises determining a frequency and damping rate of said vibration, wherein said step of determining comprises determining a Fourier transform of said change in optical response, and wherein said Fourier transform yields a Fourier spectrum, and said method comprises further steps of
- relating a peak of said Fourier spectrum to said frequency;
- and
- relating a width of said peak to said damping rate.
A method for characterizing a sample having a structure disposed on or within said sample, comprising the steps of:
- applying a first pulse of light to a surface of said sample to excite said structure into a vibration in at least one normal mode of vibration of said structure;
- applying a second pulse of light to said surface;
- sensing from a reflection of said second pulse a change in optical response of said sample;
- relating said change in optical response to an oscillatory component of said vibration;
- and
- associating said oscillatory component to at least one of a spatial or electrical characteristic of said structure, wherein said step of relating comprises fitting said change in optical response to a sum of damped oscillations with different frequencies.
A non-destructive system for characterizing a sample having a structure disposed on or within said sample, comprising:
- an optical source unit for applying a first pulse of light to a surface of said sample to excite said structure into a vibration in at least one normal mode of vibration of said structure, and for applying a second pulse of light to said surface;
- a sensor for sensing from a reflection of said second pulse a change in a transient optical response of said sample;
- and
- a processor for relating said change in the transient optical response to an oscillatory component of said vibration, and for associating said oscillatory component to a parameter of said structure.
A non-destructive system for characterizing a sample having a structure disposed on or within said sample, comprising:
- an optical source unit for applying a first pulse of light to a surface of said sample to excite said structure into a vibration in at least one normal mode of vibration of said structure, and for applying a second pulse of light to said surface;
- a sensor for sensing from a reflection of said second pulse a change in optical response of said sample;
- and
- a processor for relating said change in optical response to an oscillatory component of said vibration, and for associating said oscillatory component to a parameter of said structure, wherein said processor further operates to determine a frequency and damping rate of said vibration, wherein said processor further operates to determine a Fourier transform of said change in optical response, and wherein said Fourier transform yields a Fourier spectrum, and wherein said processor further operates to relate a peak of said Fourier spectrum to said frequency, and to relate a width of said peak to said damping rate.
A non-destructive system for characterizing a sample having a structure disposed on or within said sample, comprising:
- an optical source unit for applying a first pulse of light to a surface of said sample to excite said structure into a vibration in at least one normal mode of vibration of said structure, and for applying a second pulse of light to said surface;
- a sensor for sensing from a reflection of said second pulse a change in optical response of said sample;
- and
- a processor for relating said change in optical response to an oscillatory component of said vibration, and for associating said oscillatory component to a parameter of said structure, wherein said processor further operates to fit said change in optical response to a sum of damped oscillations and frequencies.
Dependencies are inferred from the claim text.