Abstract: The disclosure is directed to systems for providing illumination to a measurement head for optical metrology. In some embodiments of the disclosure, illumination beams from a plurality of illumination sources are combined to deliver illumination at one or more selected wavelengths to the measurement head. In some embodiments of the disclosure, intensity and/or spatial coherence of illumination delivered to the measurement head is controlled. In some embodiments of the disclosure, illumination at one or more selected wavelengths is delivered from a broadband illumination source configured for providing illumination at a continuous range of wavelengths.

Abstract: A metrology system for determining overlay is disclosed. The system includes an optical assembly for capturing images of an overlay mark and a computer for analyzing the captured images to determine whether there is an overlay error. The mark comprises first and second regions that each include at least two separately generated working zones, juxtaposed relative to one another, configured to provide overlay information in a first direction, and include a periodic structure having coarsely segmented elements. The mark comprises third and fourth regions that each include at least two separately generated working zones, juxtaposed relative to one another, configured to provide overlay information in a second direction, and include a periodic structure having coarsely segmented elements.

Abstract: Imaging metrology targets and methods are provided, which combine one-dimensional (1D) elements designed to provide 1D imaging metrology signals along at least two measurement directions and two-dimensional (2D) elements designed to provide at least one 2D imaging metrology overlay signal. The target area of the 1D elements may enclose the 2D elements or the target areas of the 1D and 2D elements may be partially or fully congruent. The compound targets are small, possible multilayered, and may be designed to be process compatible (e.g., by segmentation of the elements, interspaces between elements and element backgrounds) and possibly be produced in die. 2D elements may be designed to periodic to provide additional one dimensional metrology signals.

Abstract: Disclosed is a scatterometry mark for determining an overlay error, critical dimension, or profile of the mark. The mark includes a first plurality of periodic structures on a first layer, a second plurality of periodic structures on a second layer, and a third plurality of periodic structures on a third layer that is underneath the first and second layer. The third periodic structures are perpendicular to the first and second structures, and the third periodic structures have one or more characteristics so as to result in a plurality of lower structures beneath the third periodic structures being screened from significantly affecting at least part of a spectrum of a plurality of scattered signals detected from the first and second periodic structures for determining an overlay error, critical dimension, or profile of the first and second periodic structures or at least one of such detected scattered signals.

Abstract: Disclosed is a scatterometry mark for determining an overlay error, critical dimension, or profile of the mark. The mark includes a first plurality of periodic structures on a first layer, a second plurality of periodic structures on a second layer, and a third plurality of periodic structures on a third layer that is underneath the first and second layer. The third periodic structures are perpendicular to the first and second structures, and the third periodic structures have one or more characteristics so as to result in a plurality of lower structures beneath the third periodic structures being screened from significantly affecting at least part of a spectrum of a plurality of scattered signals detected from the first and second periodic structures for determining an overlay error, critical dimension, or profile of the first and second periodic structures or at least one of such detected scattered signals.

Abstract: Systems and method are provided for analyzing target, process and metrology configuration sensitivities to a wide range of parameters, according to external requirements or inner development and verification needs. Systems comprise the following elements. An input module is arranged to receive parameters relating to targets, target metrology conditions and production processes, to generate target data. A metrology simulation unit is arranged to simulate metrology measurements of targets from the target data and to generate multiple metrics that quantify the simulated target measurements. A sensitivity analysis module is arranged to derive functional dependencies of the metrics on the parameters and to define required uncertainties of the parameters with respect to the derived functional dependencies. Finally, a target optimization module is arranged to rank targets and target metrology conditions with respect to the simulated target measurements.

Abstract: A semiconductor target for determining a relative shift between two or more successive layers of a substrate is provided. The target comprises a plurality of first structures formed in a first layer, and the first structures have a first center of symmetry (COS). The target further comprises a plurality of second structures formed in a second layer, and the second structures have second COS. The difference between the first COS and the second COS corresponds to an overlay error between the first and second layer and wherein the first and second structures have a 180° rotational symmetry, without having a 90° rotational symmetry, with respect to the first and second COS, respectively.

Abstract: The disclosure is directed to various apodization schemes for pupil imaging scatterometry. In some embodiments, the system includes an apodizer disposed within a pupil plane of the illumination path. In some embodiments, the system further includes an illumination scanner configured to scan a surface of the sample with at least a portion of apodized illumination. In some embodiments, the system includes an apodized pupil configured to provide a quadrupole illumination function. In some embodiments, the system further includes an apodized collection field stop. The various embodiments described herein may be combined to achieve certain advantages.

Abstract: Methods and systems for minimizing of algorithmic inaccuracy in scatterometry overlay (SCOL) metrology are provided. SCOL targets are designed to limit the number of oscillation frequencies in a functional dependency of a resulting SCOL signal on the offset and to reduce the effect of higher mode oscillation frequencies. The targets are segmented in a way that prevents constructive interference of high modes with significant amplitudes, and thus avoids the inaccuracy introduced by such terms into the SCOL signal. Computational methods remove residual errors in a semi-empirical iterative process of compensating for the residual errors algorithmically or through changes in target design.

Abstract: The disclosure is directed to various apodization schemes for pupil imaging scatterometry. In some embodiments, the system includes an apodizer disposed within a pupil plane of the illumination path. In some embodiments, the system further includes an illumination scanner configured to scan a surface of the sample with at least a portion of apodized illumination. In some embodiments, the system includes an apodized pupil configured to provide a quadrupole illumination function. In some embodiments, the system further includes an apodized collection field stop. The various embodiments described herein may be combined to achieve certain advantages.

Abstract: In one embodiment, a semiconductor target for determining overlay error, if any, between two or more successive layers of a substrate or between two or more separately generated patterns on a single layer of a substrate is disclosed. The target comprises at least a plurality of first structures that are invariant for a plurality of first rotation angles with respect to a first center of symmetry (COS) of the first structures and a plurality of second structures that are invariant for a plurality of second rotation angles with respect to a second COS of the second structures. The first rotation angles differ from the second rotation angles, and first structures and second structures are formed on different layers of the substrate or separately generated patterns on a same layer of the substrate.

Abstract: A thin overlay structure for use in imaging based metrology is disclosed. The thin overlay structure may include a first structure and second structure, the first and second structures designed to have a common center of symmetry, both structures being invariant to a 180 degree rotation about the common center of symmetry, wherein a mark region defining the extent of the structures is characterized by a first direction and a second direction orthogonal to the first direction, a length of the mark region along the first direction being greater than a length of the mark region along the second direction.

Abstract: The disclosure is directed to various apodization schemes for pupil imaging scatterometry. In some embodiments, the system includes an apodizer disposed within a pupil plane of the illumination path. In some embodiments, the system further includes an illumination scanner configured to scan a surface of the sample with at least a portion of apodized illumination. In some embodiments, the system includes an apodized pupil configured to provide a quadrupole illumination function. In some embodiments, the system further includes an apodized collection field stop. The various embodiments described herein may be combined to achieve certain advantages.

Abstract: Methods and systems are provided, which identify specified metrology target abnormalities using selected metrics and classify the identified target abnormalities geometrically to link them to corresponding sources of error. Identification may be carried out by deriving target signals such as kernels from specified regions of interest (ROIs) from corresponding targets on a wafer, calculating the metrics from the target signals using respective functions and analyzing the metrics to characterize the targets.

Abstract: A thin overlay structure for use in imaging based metrology is disclosed. The thin overlay structure may include a first structure and second structure, the first and second structures designed to have a common center of symmetry, both structures being invariant to a 180 degree rotation about the common center of symmetry, wherein a mark region defining the extent of the structures is characterized by a first direction and a second direction orthogonal to the first direction, a length of the mark region along the first direction being greater than a length of the mark region along the second direction.

Abstract: In one embodiment, a semiconductor target for determining overlay error, if any, between two or more successive layers of a substrate or between two or more separately generated patterns on a single layer of a substrate is disclosed. The target comprises at least a plurality of first structures that are invariant for a plurality of first rotation angles with respect to a first center of symmetry (COS) of the first structures and a plurality of second structures that are invariant for a plurality of second rotation angles with respect to a second COS of the second structures. The first rotation angles differ from the second rotation angles, and first structures and second structures are formed on different layers of the substrate or separately generated patterns on a same layer of the substrate.

Abstract: A semiconductor wafer may include a dummy field configured to enable overlay measurements. The enhanced dummy field may include a plurality of encoding blocs that enable OVL measurements to be made throughout the enhanced dummy field.

Abstract: In one embodiment, a metrology target for determining a relative shift between two or more successive layers of a substrate may comprise; an first structure on a first layer of a substrate and an second structure on a successive layer to the first layer of the substrate arranged to determine relative shifts in alignment in both the x and y directions of the substrate by analyzing the first structure and second structure overlay.

Abstract: An overlay mark for determining the relative shift between two or more successive layers of a substrate is disclosed. The overlay mark includes at least one test pattern for determining the relative shift between a first and a second layer of the substrate in a first direction. The test pattern includes a first set of working zones and a second set of working zones. The first set of working zones are disposed on a first layer of the substrate and have at least two working zones diagonally opposed and spatially offset relative to one another. The second set of working zones are disposed on a second layer of the substrate and have at least two working zones diagonally opposed and spatially offset relative to one another. The first set of working zones are generally angled relative to the second set of working zones thus forming an “X” shaped test pattern.

Abstract: Disclosed are overlay targets having flexible symmetry characteristics and metrology techniques for measuring the overlay error between two or more successive layers of such targets. Techniques for imaging targets with flexible symmetry characteristics and analyzing the acquired images to determine overlay or alignment error are disclosed.