TARGET FOR MEASURING A PARAMETER OF A LITHOGRAPHIC PROCESS

    公开(公告)号:US20220035255A1

    公开(公告)日:2022-02-03

    申请号:US17299531

    申请日:2019-12-04

    Abstract: A target for determining a performance parameter of a lithographic process, the target comprising a first sub-target formed by at least two overlapping gratings, wherein the underlying grating of the first sub-target has a first pitch and the top lying grating of the first sub-target has a second pitch, at least a second sub-target formed by at least two overlapping gratings, wherein the underlying grating of the second sub-target has a third pitch and the top lying grating of the second sub-target has a fourth pitch.

    Method of Measuring a Target, and Metrology Apparatus

    公开(公告)号:US20190219931A1

    公开(公告)日:2019-07-18

    申请号:US16246004

    申请日:2019-01-11

    Abstract: Disclosed is a method of measuring a target, and a metrology apparatus. In one arrangement the target comprises a layered structure. The layered structure has a first target structure in a first layer and a second target structure in a second layer. The method comprises illuminating the target with measurement radiation using an illumination profile in the illumination pupil (u) that is offset from an imaginary line (IL) in the illumination pupil passing through the optical axis, to allow propagation to a detection region of the detection pupil of an allowed order (v2, v4) of a predetermined diffraction order while limiting propagation to the detection region of an equal and opposite order (v1′, v3′) of that predetermined diffraction order. Scattered radiation of plural double-diffracted allowed diffraction orders (w2, w4) is detected. A characteristic of the lithographic process is calculated using the detected scattered radiation of the predetermined diffraction orders.

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