Method of fast surface particle and scratch detection for euv mask backside
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsChih-Cheng CHEN, ShinAn KU, Ting-Hao HSU, Hsin-Chang LEE
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Abstract
A method of scanning a substrate and determining scratches of the substrate includes transmitting a converging beam of light that comprises multiple wavelengths to the substrate. Each wavelength of the multiple wavelengths focuses at a different distance in a focus interval around and including a surface of the substrate. The method also includes receiving reflected light from the surface of the substrate and determining a height or depth of the surface of the substrate based on a wavelength of the reflected light a highest intensity.
Claims20
A method of scanning a substrate, comprising:
- transmitting a converging beam of light that comprises multiple wavelengths to the substrate, wherein each wavelength of the multiple wavelengths is configured to focus at a different distance in a focus interval around and comprising a surface of the substrate;
- receiving reflected light from the surface of the substrate;
- and
- determining a height or depth of the surface of the substrate based on a wavelength of the reflected light having a highest intensity.
A method of scanning a substrate, comprising:
- receiving reflected light from a first point on a surface of the substrate;
- configuring the reflected light to pass through a pinhole;
- detecting the reflected light from the first point after passing the pinhole;
- determining a spectrum of the detected reflected light;
- determining a first wavelength of a peak intensity of the spectrum;
- and
- determining a height or depth of the first point on the surface of the substrate based on the first wavelength of the peak intensity.
A system for scanning a substrate, comprising:
- a main controller;
- a light source coupled to the main controller and configured to transmit a beam of light that comprises multiple wavelengths to the substrate;
- a stage coupled to the main controller and configured to move the substrate;
- an optical system disposed in a light path between the light source and the substrate and coupled to the main controller and configured for focusing the beam of light on a surface of the substrate;
- and
- a spectrometer to receive the beam of light reflected from the surface of the substrate and directed by the optical system and configured for:
- detecting reflected light from a first point on the surface of the substrate;
- determining a spectrum of the detected reflected light;
- determining a first wavelength of a peak intensity of the spectrum;
- and
- determining a height or depth of the first point on the surface of the substrate based on the first wavelength of the peak intensity.
Dependencies are inferred from the claim text.