Method for monitoring the rate of etching of a semiconductor
AssigneeInfineon Technologies AG
InventorsShoaib Hasan Zaidi, Gangadhara S. Mathad
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Abstract
A method of measuring the rate of etching of trenches on a substrate using interferometry is provided. The method comprises transmitting onto the substrate incident electromagnetic radiation having a wavelength above the wavelength at which the trenches act as waveguides for the radiation; collecting reflected electromagnetic radiation from the substrate; detecting a repetitive pattern of maximum intensities and minimum intensities of the reflected electromagnetic radiation during the etching; and determining the rate of etching based upon the wavelength of the incident electromagnetic radiation and the time period of the pattern.
Claims32
A method of measuring the rate of etching of trenches on a substrate using interferometry comprising:
- transmitting onto the substrate incident electromagnetic radiation having a wavelength above the wavelength at which the trenches act as waveguides for the radiation;
- collecting reflected electromagnetic radiation from the substrate;
- detecting a repetitive pattern of maximum intensities and minimum intensities of the reflected electromagnetic radiation during the etching;
- and
- determining the rate of etching based upon the wavelength of the incident electromagnetic radiation and the time period of the pattern.
A method of determining the depth of trenches on a substrate using interferometry comprising:
- transmitting onto the substrate incident electromagnetic radiation having a wavelength greater than the cutoff wavelength for the trenches to act as waveguides for the radiation;
- collecting reflected electromagnetic radiation from the substrate;
- detecting a repetitive pattern of maximum intensities and minimum intensities of the reflected electromagnetic radiation;
- and
- determining the depth of the trenches based upon the wavelength of the incident electromagnetic radiation and the time period of the pattern.
Dependencies are inferred from the claim text.