Abstract: A pattern formed on a substrate includes first and second sub-patterns positioned adjacent one another and having respective first and second periodicities. The pattern is observed to obtain a combined signal which includes a beat component having a third periodicity at a frequency lower than that of the first and second periodicities. A measurement of performance of the lithographic process is determined by reference to a phase of the beat component. Depending how the sub-patterns are formed, the performance parameter might be critical dimension (CD) or overlay, for example. For CD measurement, one of the sub-patterns may comprise marks each having of a portion sub-divided by product-like features. The measurement can be made using an existing alignment sensor of a lithographic apparatus. Sensitivity and accuracy of the measurement can be adjusted by selection of the first and second periodicities, and hence the third periodicity.

Abstract: Measurement targets for use on substrates, and overlay targets are presented. The targets include an array of first regions alternating with second regions, wherein the first regions include structures oriented in a first direction and the second regions include structures oriented in a direction different from the first direction. The effective refractive index of the two sets of regions are thereby different when experienced by a polarized beam, which will act as a TM-polarized beam when reflected from the first set of regions, but as a TE-polarized beam when reflected from the second set of regions.

Abstract: An alignment measurement system measures an alignment target on an object. A measurement illuminates the target and is reflected. The reflected measurement beam is split and its parts are differently polarized. A detector receives the reflected measurement beam. A processing unit determines alignment on the basis of the measurement beam received by the detector. An alternative arrangement utilizes an optical dispersive fiber to guide a multi-wavelength measurement beam reflected from the object to a detector.

Abstract: An alignment measurement system measures an alignment target on an object. A measurement illuminates the target and is reflected. The reflected measurement beam is split and its parts are differently polarized. A detector receives the reflected measurement beam. A processing unit determines alignment on the basis of the measurement beam received by the detector. An alternative arrangement utilizes an optical dispersive fiber to guide a multi-wavelength measurement beam reflected from the object to a detector.

Abstract: An alignment measurement system measures an alignment target on an object. A measurement illuminates the target and is reflected. The reflected measurement beam is split and its parts are differently polarized. A detector receives the reflected measurement beam. A processing unit determines alignment on the basis of the measurement beam received by the detector. An alternative arrangement utilizes an optical dispersive fiber to guide a multi-wavelength measurement beam reflected from the object to a detector.

Abstract: The invention relates to a marker structure for optical alignment of a substrate and provided thereon. The marker structure has a first reflecting surface at a first level and a second reflecting surface at a second level. A separation between the first level and the second level determines a phase depth condition. The marker structure further has an additional structure. The additional structure is arranged to modify the separation during manufacture of the marker structure. The invention further relates to a method of forming such a marker structure.

Abstract: The invention relates to a marker structure for optical alignment of a substrate and provided thereon. The marker structure has a first reflecting surface at a first level and a second reflecting surface at a second level. A separation between the first level and the second level determines a phase depth condition. The marker structure further has an additional structure. The additional structure is arranged to modify the separation during manufacture of the marker structure. The invention further relates to a method of forming such a marker structure.

Abstract: A substrate stage for an immersion type lithographic apparatus is arranged to project a patterned radiation beam from a patterning device onto a substrate, the substrate stage being constructed to hold the substrate and including at least a sensor for sensing the patterned radiation beam, the sensor including an at least partially transmissive layer having a front side facing the incoming radiation beam and a back side opposite the front side, wherein the back side is provided with at least a sensor mark to be subjected to the radiation beam transmitted through the layer.

Abstract: An alignment mark on a substrate includes a periodic structure of a plurality of first elements and a plurality of second elements. The elements are arranged in an alternating repetitive sequence in a first direction. An overall pitch of the periodic structure is equal to a sum of a width of the first element and a width of the second element in the first direction. Each first element has a first periodic sub-structure with a first sub-pitch and each second element has a second periodic sub-structure with second sub-pitch. An optical property of the first element for interaction with a beam of radiation having a wavelength ? is different from the optical property of the second element. The overall pitch is larger than the wavelength ?, and each of the first and the second sub-pitch is smaller than the wavelength.

Abstract: A pattern formed on a substrate includes first and second sub-patterns positioned adjacent one another and having respective first and second periodicities. The pattern is observed to obtain a combined signal which includes a beat component having a third periodicity at a frequency lower than that of the first and second periodicities. A measurement of performance of the lithographic process is determined by reference to a phase of the beat component. Depending how the sub-patterns are formed, the performance parameter might be critical dimension (CD) or overlay, for example. For CD measurement, one of the sub-patterns may comprise marks each having of a portion sub-divided by product-like features. The measurement can be made using an existing alignment sensor of a lithographic apparatus. Sensitivity and accuracy of the measurement can be adjusted by selection of the first and second periodicities, and hence the third periodicity.

Abstract: An alignment measurement system measures an alignment target on an object. A measurement illuminates the target and is reflected. The reflected measurement beam is split and its parts are differently polarized. A detector receives the reflected measurement beam. A processing unit determines alignment on the basis of the measurement beam received by the detector. An alternative arrangement utilizes an optical dispersive fiber to guide a multi-wavelength measurement beam reflected from the object to a detector.

Abstract: The position of a product is measured using an alignment mark on the product. Radiation is transmitted towards the alignment mark and diffracted by a pattern in the alignment mark. Position information is determined from phase relations of the diffracted radiation. The alignment mark comprises a set of mutually parallel conductor tracks from which the diffracted radiation is collected, the pattern being defined by a pattern of variation of the pitch between successive tracks as a function of position along the surface of the product. Thus, for example the pattern comprises alternating first and second areas wherein the pitch has a first and second value, respectively. Because the tracks in the different parts of the pattern, such as the first and second areas, are parallel to each other improved measurements are possible.

Abstract: A method of production of alignment marks uses a self-aligned double patterning process. An alignment mark pattern is provided with first and second sub-segmented elements. After selecting the dipolar illumination orientation, dipole-X is used to illuminate the pattern and to image the first elements on the wafer, but not the second elements. Alternatively, dipole-Y is used to illuminate the pattern and to image the second elements on the wafer, but not the first elements. In either case, self-aligned double patterning processing may then be performed to produce product-like alignment marks with high contrast and wafer quality (WQ). Subsequently the X and Y alignment marks thus produced are used for the step of alignment in a lithographic process.

Abstract: Measurement targets for use on substrates, and overlay targets are presented. The targets include an array of first regions alternating with second regions, wherein the first regions include structures oriented in a first direction and the second regions include structures oriented in a direction different from the first direction. The effective refractive index of the two sets of regions are thereby different when experienced by a polarized beam, which will act as a TM-polarized beam when reflected from the first set of regions, but as a TE-polarized beam when reflected from the second set of regions.

Abstract: Alignment marks for use on substrates. In one example, the alignment marks consist of periodic 2-dimensional arrays of structures, the spacing of the structures being smaller than an alignment beam but larger than an exposure beam.

Abstract: The present invention relates to alignment marks for use on substrates, the alignment marks consisting of periodic 2-dimensional arrays of structures, the spacing of the structures being smaller than an alignment beam but larger than an exposure beam and the width of the structures varying sinusoidally from one end of an array to the other.

Abstract: Alignment marks for use on substrates. An exemplary implementation provides phase depth control. A grating mark, for example, can be etched on a silicon wafer with sub-wavelength segmentation in the spacing portion of the alignment grating's period. The sub-wavelength segmentation can be applied to the spaces or to the lines, or both, of an alignment grating to control the phase depth of the grating. By applying segmentation with a period smaller than the alignment light wavelength in either the space(s) and/or in the line(s) of the grating, the effective refractive index in that region can be manipulated. This change in the effective index will result in a change in the phase depth (optical path length). By varying the duty cycle of the sub-wavelength segmented region, the effective refractive index can be controlled, thereby providing selective control over the phase depth.

Abstract: A substrate stage for an immersion type lithographic apparatus is arranged to project a patterned radiation beam from a patterning device onto a substrate, the substrate stage being constructed to hold the substrate and including at least a sensor for sensing the patterned radiation beam, the sensor including an at least partially transmissive layer having a front side facing the incoming radiation beam and a back side opposite the front side, wherein the back side is provided with at least a sensor mark to be subjected to the radiation beam transmitted through the layer.

Abstract: An alignment mark on a substrate includes a periodic structure of a plurality of first elements and a plurality of second elements. The elements are arranged in an alternating repetitive sequence in a first direction. An overall pitch of the periodic structure is equal to a sum of a width of the first element and a width of the second element in the first direction. Each first element has a first periodic sub-structure with a first sub-pitch and each second element has a second periodic sub-structure with second sub-pitch. An optical property of the first element for interaction with a beam of radiation having a wavelength ? is different from the optical property of the second element. The overall pitch is larger than the wavelength ?, and each of the first and the second sub-pitch is smaller than the wavelength.

Abstract: A method for alignment mark preservation includes a step of preparing a lower alignment mark structure on a substrate. In one configuration of the invention, the alignment mark structure includes a lower trench. In a further step, a hard mask coating is applied to a substrate that includes the alignment marks. Preferably, the hard mask material is an amorphous carbon material. In a further step, a selected portion of the hard mask located above the lower alignment mark structure is exposed to a dose of radiation. In one aspect of the invention, the surface of regions of the hard mask coating that receive the dose of radiation become elevated with respect to other regions of the hard mask surface. For those elevated regions of the hard mask that are aligned with an underlying alignment mark trench, the elevated regions serve as an alignment mark that preserves the original horizontal position of the underlying alignment mark.