| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a target capable of providing a scatterometry target, and of reducing the size of a diffraction grating of the target without impairing a further high-order diffraction order when the pitch of the diffraction grating is smaller than the wavelength of a measurement radiation beam. <P>SOLUTION: An overlay target on a substrate is disclosed, the overlay target including a periodic array of structures wherein every structure is different from the rest of the structures. The periodic array is desirably made of two interlaced diffraction gratings, one of the gratings having a different pitch from the other grating in order to form an asymmetry in the array. This asymmetry can then be measured by measuring the diffraction spectra of radiation reflected from the overlay target. Variation in the asymmetry indicates the presence of an overlay error in layers on the substrate, where overlay targets are printed on subsequent layers. <P>COPYRIGHT: (C)2009,JPO&INPIT |
