METROLOGY METHOD AND ASSOCIATED METROLOGY DEVICE

摘要

Embodiments of the invention arc disclosed in the claims and in the detailed description. In a first aspect of the invention (here is provided a dark-field metrology method comprising: obtaining at least first diffracted radiation data and second diffracted radiation data, said first diffracted radiation data relating to a first portinn of a diffraction order, and said second diffracted radiation data relating to a second portion of the diffraction order, wherein said first portion of the diffraction order and second portion of the diffraction order relate to respective portions of a detection pupil plane or conjugate thereof; determining a first partial electric field from a measurement parameter of said first diffracted radiation data; determining a second partial electric field from a measurement parameter of said second diffracted radiation data; and determining an electric field of said diffraction order from said first partial electric field and said second partial electric field. In a second aspect of the invention there is provided a dark-field metrology device, comprising: an illumination arrangement for illuminating a structure on a substrate so as to generate at least one diffraction order; a detection arrangement for detecting said at least one diffraction order or a portion thereof; a spatial filter arrangement in a detection pupil plane or conjugate thereof of the dark-field metrology device, the spatial filter arrangement being operable to separately transmit at least a first portion of the diffraction order and a second portion of the diffraction order such that they are separately detected on the detection arrangement; and a processor operable to: determine a first partial electric field from a measurement parameter of first diffracted radiation data relating to the first portion of the diffraction order; determine a second partial electric field from a measurement parameter of second diffracted radiation data relating to said the second portion of a diffraction order, and determine an electric field of said diffraction order from at least said first partial electric field and said second partial electric Held. These and wther aspects and advantages of the apparatus and methods disclosed herein will be appreciated from a consideration of the following description and drawings of exemplary embodiments.