Gate stack metrology
AssigneeKLA-Tencor Corporation
InventorsGhuorong V. Zhuang, John Fielden
Life of this patent
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Abstract
An x-ray photoelectron spectroscopy apparatus for measuring film stack characteristics, of the type having an x-ray source and an x-ray photoelectron spectroscopy module coupled to a contiguous vacuum environment, including an ultraviolet source and an ultraviolet photoelectron spectroscopy module coupled to the vacuum environment.
Claims20
In an x-ray photoelectron spectroscopy apparatus for measuring film stack characteristics, of the type having an x-ray source and an x-ray photoelectron spectroscopy module coupled to a contiguous vacuum environment, the improvement comprising:
- an ultraviolet source coupled to the vacuum environment, and
- an ultraviolet photoelectron spectroscopy module coupled to the vacuum environment,
- where the ultraviolet source and the x-ray source are positioned to inspect a common side of the film stack.
In an x-ray photoelectron spectroscopy apparatus for measuring film stack characteristics, of the type having an x-ray source and an x-ray photoelectron spectroscopy module coupled to a contiguous vacuum environment, the improvement comprising an optical metrology module coupled to the vacuum environment, where the optical metrology module and the x-ray source are positioned to inspect a common side of the film stack.
A method to determine characteristics of a film stack on a substrate, the method comprising the steps of:
- acquiring an ultraviolet photoelectron spectroscopy spectrum of the film stack within a contiguous vacuum environment,
- determining the band edge of the film stack from the ultraviolet photoelectron spectroscopy spectrum,
- determining the stoichiometry of the film stack from the band edge,
- calculating the electron inelastic mean free path of the film stack from the stoichiometry,
- acquiring an x-ray photoelectron spectroscopy spectrum of the substrate within the contiguous vacuum environment, and
- determining the film stack thickness from the substrate x-ray photoelectron spectroscopy spectrum and the electron inelastic mean free path of the film stack.
A method to determine characteristics of a film stack on a substrate, the method comprising the steps of:
- acquiring an ultraviolet photoelectron spectroscopy spectrum of the film stack within a contiguous vacuum environment,
- determining the band edge of the film stack from the ultraviolet photoelectron spectroscopy spectrum,
- determining the stoichiometry of the film stack from the band edge,
- acquiring a vacuum ultraviolet photoelectron spectroscopy spectrum of the film stack within the contiguous vacuum environment,
- iterating the steps of,
- constructing a model of the film stack using an estimated thickness,
- theorizing a spectrum for the film stack based on the estimated thickness,
- comparing the theorized spectrum to the measured spectrum, and
- revising the estimated thickness,
- until the theorized spectrum matches the measured spectrum to within a desired tolerance, and
- reporting the estimated thickness as the actual thickness of the film stack.
Dependencies are inferred from the claim text.