Method and apparatus for film-thickness measurements
AssigneePhilips Electronics North America Corporation
InventorsMartin Fuchs, Michael A. Joffe, Matt Banet
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Abstract
The invention describes a method for measuring a property of a sample by: 1) irradiating a portion of the sample with an excitation pattern characterized by at least one spatial phase and spatial period; 2) diffracting a portion of a probe beam off a surface of the sample; 3) detecting the diffracted portion of the probe beam with an optical detector to generate a light-induced signal; 4) adjusting the spatial phase of the excitation pattern; 5) repeating the irradiating, diffracting and detecting steps to generate an additional light-induced signal; and 6) processing the light-induced signals to determine a property of the sample.
Claims33
A method for measuring a sample, comprising the steps of:
- (a) irradiating a portion of the sample with an excitation pattern characterized by at least one spatial phase and spatial period;
- (b) diffracting a portion of a probe beam off a surface of the sample;
- (c) detecting the diffracted portion of the probe beam with an optical detector to generate a light-induced signal;
- (d) dithering the spatial phase of the excitation pattern;
- (e) repeating the irradiating, diffracting and detecting steps to generate an additional light-induced signal;
- and
- (f) processing the light-induced signals to determine a property of the sample.
An apparatus for measuring a sample, comprising:
- a) a first light source that generates an optical excitation pulse;
- b) an optical system aligned to receive the optical excitation pulse, separate it into at least two optical pulses, and focus at least one pulse onto a surface of the sample to form an excitation pattern characterized by at least one spatial phase and at least one spatial period;
- c) a phase-dithering component that dithers the spatial phase of excitation pattern while the sample is being measured;
- d) a second light source that generates a probe beam that diffracts off the sample;
- e) an optical detector that detects the diffracted portion of the probe beam to generate a light-induced signal;
- and
- f) a processor configured to process the light-induced signal from the optical detector to determine a property of the sample.
Dependencies are inferred from the claim text.