APPARATUS AND METHODS FOR DETECTING OVERLAY ERRORS USING SCATTEROMETRY
    2.
    发明公开
    APPARATUS AND METHODS FOR DETECTING OVERLAY ERRORS USING SCATTEROMETRY 有权
    装置和一种用于识别覆盖误差按用途杂散测量调查研究

    公开(公告)号:EP1570232A4

    公开(公告)日:2007-08-29

    申请号:EP03796723

    申请日:2003-12-05

    CPC classification number: G03F9/7088 G03F7/70633 G03F9/7049 G03F9/7084

    Abstract: Disclosed are techniques, apparatus, and targets for determining overlay error between two layers of a sample. In one embodiment, a method for determining overlay between a plurality of first structures in a first layer of a sample and a plurality of second structures in a second layer of the sample is disclosed. Targets A, B, C and D that each include a portion of the first and second structures are provided. Target A is designed to have an offset Xa between its first and second structures portions; target B is designed to have an offset Xb between its first and second structures portions; target C is designed to have an offset Xc between its first and second structures portions; and target D is designed to have an offset Xd between its first and second structures portions. Each of the offsets Xa, Xb, Xc and Xd is preferably different from zero; Xa is an opposite sign and differ from Xb; and Xc is an opposite sign and differs from Xd. The targets A, B, C and D are illuminated with electromagnetic radiation to obtain spectra SA, SB, SC, and SD from targets A, B, C, and D, respectively. Any overlay error between the first structures and the second structures is then determined using a linear approximation based on the obtained spectra SA, SB, SC, and SD.

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