Thin film metrology
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsChih Hung Chen, Kei-Wei Chen, Te-Ming Kung
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Abstract
A method of evaluating a thickness of a film on a substrate includes detecting atomic force responses of the film to exposure of electromagnetic radiation in the infrared portion of the electromagnetic spectrum. The use of atomic force microscopy to evaluate thicknesses of thin films avoids underlayer noise commonly encountered when optical metrology techniques are utilized to evaluate film thicknesses. Such underlayer noise adversely impacts the accuracy of the thickness evaluation.
Claims20
A method for evaluating thickness of a conductive or nonconductive film on a wafer, comprising:
- exposing the film to an infrared portion of the electromagnetic spectrum;
- performing a scanning probe microscopy measurement on the film using a scanning probe microscope;
- detecting a scanning probe microscopy response of the film in response to the exposing the film to the infrared portion of the electromagnetic spectrum;
- and
- using the scanning probe microscopy response of the film from the detecting step to determine a thickness of the film.
A method for evaluating relative thickness of a first film on a substrate and a second film on the substrate comprising:
- exposing the first film to an infrared portion of the electromagnetic spectrum;
- performing a scanning probe microscopy measurement on the first film using a scanning probe microscope;
- detecting a scanning probe microscopy response of the first film in response to the exposing of the first film to the infrared portion of the electromagnetic spectrum;
- exposing the second film to an infrared portion of the electromagnetic spectrum;
- performing a scanning probe microscopy measurement on the second film using a scanning probe microscope;
- detecting a scanning probe microscopy response of the second film in response to exposing the second film to the infrared portion of the electromagnetic spectrum;
- and
- using the detected scanning probe microscopy response of the first film and the detected scanning probe microscopy response of the second film to evaluate a relative thickness of the first film with respect to the second film.
A method for evaluating thickness of an uppermost film on a substrate, comprising:
- exposing the uppermost film and an underlying film on the substrate to electromagnetic radiation in the infrared portion of the electromagnetic spectrum;
- while exposing the uppermost film and the underlying film to the electromagnetic radiation in the infrared portion of the electromagnetic spectrum, performing a scanning probe microscopy measurement on at least the underlying film using a scanning probe microscope operating in a non-contact mode;
- detecting a scanning probe microscopy response of the underlying film at a first wavelength of the electromagnetic radiation in the infrared portion of the electromagnetic spectrum;
- and
- using the detected scanning probe microscopy response of the underlying film at the first wavelength to evaluate a thickness of the uppermost film.
Dependencies are inferred from the claim text.