Abstract: A pattern from a patterning device is applied to a substrate by a lithographic apparatus. The applied pattern includes product features and metrology targets. The metrology targets include large targets and small targets which are for measuring overlay. Some of the smaller targets are distributed at locations between the larger targets, while other small targets are placed at the same locations as a large target. By comparing values measured using a small target and large target at the same location, parameter values measured using all the small targets can be corrected for better accuracy. The large targets can be located primarily within scribe lanes while the small targets are distributed within product areas.

Abstract: Asymmetry properties of a periodic target on a substrate, such as a grating on a wafer, are determined. An inspection apparatus has a broadband illumination source with illumination beams point mirrored in the pupil plane of a high numerical aperture objective lens. The substrate and target are illuminated via the objective lens from a first direction and a second direction mirror reflected with respect to the plane of the substrate. A quad wedge optical device separately redirects diffraction orders of radiation scattered from the substrate and separates diffraction orders from illumination along each of the first and second directions. For example the zeroth and first orders are separated for each incident direction. After capture in multimode fibers, spectrometers are used to measure the intensity of the separately redirected diffraction orders as a function of wavelength.

Abstract: A pattern from a patterning device is applied to a substrate. The applied pattern includes device functional areas and metrology target areas. Each metrology target area comprises a plurality of individual grating portions, which are used for diffraction based overlay measurements or other diffraction based measurements. The gratings are of the small target type, which is small than an illumination spot used in the metrology. Each grating has an aspect ratio substantially greater than 1, meaning that a length in a direction perpendicular to the grating lines which is substantially greater than a width of the grating. Total target area can be reduced without loss of performance in the diffraction based metrology. A composite target can comprise a plurality of individual grating portions of different overlay biases. Using integer aspect ratios such as 2:1 or 4:1, grating portions of different directions can be packed efficiently into rectangular composite target areas.

Abstract: A method of determining an overlay error. Measuring an overlay target having process-induced asymmetry. Constructing a model of the target. Modifying the model, e.g., by moving one of the structures to compensate for the asymmetry. Calculating an asymmetry-induced overlay error using the modified model. Determining an overlay error in a production target by subtracting the asymmetry-induced overlay error from a measured overlay error. In one example, the model is modified by varying asymmetry p(n?), p(n?) and the calculating an asymmetry-induced overlay error is repeated for a plurality of scatterometer measurement recipes and the step of determining an overlay error in a production target uses the calculated asymmetry-induced overlay errors to select an optimum scatterometer measurement recipe used to measure the production target.

Abstract: The present invention relates to an inspection apparatus and method which include projecting a measurement radiation beam onto a target on a substrate in order to measure the radiation reflected from the target and obtain information related to properties of the substrate. In the present embodiments, the measurement spot, which is the focused beam on the substrate, is larger than the target. Information regarding the radiation reflected from the target is kept and information regarding the radiation reflected from the surface around the target is eliminated. This is done either by having no reflecting (or no specularly reflecting) surfaces around the target or by having known structures around the target, the information from which may be recognized and removed from the total reflected beam.

Abstract: A method for inspecting semiconductor wafers and the like is presented. The method comprises initially determining a baseline greyscale difference, such as a greyscale plot or greyscale visual representation, for at least one baseline semiconductor wafer subjected to a process. The baseline greyscale difference represents a numerical difference between composite preprocessing and postprocessing greyscale representations of all pixels on the baseline semiconductor wafer. The method further comprises determining a preprocess greyscale representation for one wafer in the semiconductor wafer set and subjecting the one wafer in the semiconductor wafer set to the process, determining a postprocess greyscale representation of the one wafer in the semiconductor wafer set, and determining a difference for the one wafer in the semiconductor set. The difference represents any disparity between preprocess and postprocess greyscale representations of the one wafer in the semiconductor set.