Method and system for determining information about a target structure

    公开(公告)号:US12061421B2

    公开(公告)日:2024-08-13

    申请号:US17629053

    申请日:2020-07-17

    CPC classification number: G03F7/70633

    Abstract: Methods and systems for determining information about a target structure are disclosed. In one arrangement, a value of an asymmetry indicator for the target structure is obtained. The value of the asymmetry indicator represents an amount of an overlay independent asymmetry in the target structure. An error in an initial overlay measurement performed on the target structure at a previous time is estimated. The estimation is performed using the obtained value of the asymmetry indicator and a relationship between values of the asymmetry indicator and overlay measurement errors caused at least partially by overlay independent asymmetries. An overlay in the target structure is determined using the initial overlay measurement and the estimated error.

    Method for inferring a local uniformity metric

    公开(公告)号:US11886125B2

    公开(公告)日:2024-01-30

    申请号:US17800346

    申请日:2021-02-02

    CPC classification number: G03F7/70625

    Abstract: A method of inferring a value for at least one local uniformity metric relating to a product structure, the method including: obtaining intensity data including an intensity image relating to at least one diffraction order obtained from a measurement on a target; obtaining at least one intensity distribution from the intensity image; determining, from the at least one intensity distribution, an intensity indicator expressing a variation of either intensity over the at least one diffraction order, or a difference in intensity between two complimentary diffraction orders over the intensity image; and inferring the value for the at least one local uniformity metric from the intensity indicator.

    Metrology sensor, lithographic apparatus and method for manufacturing devices

    公开(公告)号:US10788766B2

    公开(公告)日:2020-09-29

    申请号:US16611500

    申请日:2018-03-06

    Abstract: Disclosed is a metrology sensor apparatus and associated method. The metrology sensor apparatus comprises an illumination system operable to illuminate a metrology mark on a substrate with illumination radiation having a first polarization state and an optical collection system configured to collect scattered radiation, following scattering of the illumination radiation by the metrology mark. The metrology mark comprises a main structure and changes, relative to the first polarization state, at least one of a polarization state of a first portion of the scattered radiation predominately resultant from scattering by the main structure and a polarization state of a second portion of radiation predominately resultant from scattering by one or more features other than the main structure, such that the polarization state of the first portion of the scattered radiation is different to the polarization state of the second portion of the scattered radiation. The metrology sensor apparatus further comprises an optical filtering system which filters out the second portion of the scattered radiation based on its polarization state.

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