Abstract: Methods of measuring variation across multiple instances of a pattern on a substrate or substrates after a step in a device manufacturing process are disclosed. In one arrangement, data representing a set of images is received. Each image represents a different instance of the pattern. The set of images are registered relative to each other to superimpose the instances of the pattern. Variation in the pattern is measured using the registered set of images. The pattern comprises a plurality of pattern elements and the registration comprises applying different weightings to two or more of the plurality of pattern elements. The weightings control the extent to which each pattern element contributes to the registration of the set of images. Each weighting is based on an expected variation of the pattern element to which the weighting is applied.

Abstract: A method provides the steps of receiving an image from a metrology tool, determining individual units of said image and discriminating the units which provide accurate metrology values. The images are obtained by measuring the metrology target at multiple wavelengths. The discrimination between the units, when these units are pixels in said image, is based on calculating a degree of similarity between said units.

Abstract: Methods of measuring variation across multiple instances of a pattern on a substrate or substrates after a step in a device manufacturing process are disclosed. In one arrangement, data representing a set of images is received. Each image represents a different instance of the pattern. The set of images are registered relative to each other to superimpose the instances of the pattern. Variation in the pattern is measured using the registered set of images. The pattern comprises a plurality of pattern elements and the registration comprises applying different weightings to two or more of the plurality of pattern elements. The weightings control the extent to which each pattern element contributes to the registration of the set of images. Each weighting is based on an expected variation of the pattern element to which the weighting is applied.

Abstract: Methods of measuring variation across multiple instances of a pattern on a substrate or substrates after a step in a device manufacturing process are disclosed. In one arrangement, data representing a set of images is received. Each image represents a different instance of the pattern, wherein the pattern includes a plurality of pattern elements. The set of images are registered relative to each other to superimpose the instances of the pattern. The registration includes applying different weightings to two or more of the plurality of pattern elements, wherein the weightings control the extent to which each pattern element contributes to the registration of the set of images and each weighting is based on an expected variation of the pattern element to which the weighting is applied. Variation in the pattern is measured using the registered set of images.

Abstract: Focus metrology patterns and methods are disclosed which do not rely on sub-resolution features. Focus can be measured by measuring asymmetry of the printed pattern (T), or complementary pairs of printed patterns (TN/TM). Asymmetry can be measured by scatterometry. Patterns may be printed using EUV radiation or DUV radiation. A first type of focus metrology pattern comprises first features (422) interleaved with second features (424) A minimum dimension (w1) of each first feature is close to a printing resolution. A maximum dimension (w2) of each second feature in the direction of periodicity is at least twice the minimum dimension of the first features. Each first feature is positioned between two adjacent second features such that a spacing (w1?) and its nearest second feature is between one half and twice the minimum dimension of the first features. A second type of focus metrology pattern comprises features (1122, 1124) arranged in pairs.

Abstract: Focus metrology patterns and methods are disclosed which do not rely on sub-resolution features. Focus can be measured by measuring asymmetry of the printed pattern (T), or complementary pairs of printed patterns (TN/TM). Asymmetry can be measured by scatterometry. Patterns may be printed using EUV radiation or DUV radiation. A first type of focus metrology pattern comprises first features (422) interleaved with second features (424) A minimum dimension (w1) of each first feature is close to a printing resolution. A maximum dimension (w2) of each second feature in the direction of periodicity is at least twice the minimum dimension of the first features. Each first feature is positioned between two adjacent second features such that a spacing (w1?) and its nearest second feature is between one half and twice the minimum dimension of the first features. A second type of focus metrology pattern comprises features (1122, 1124) arranged in pairs.

Abstract: Methods of measuring variation across multiple instances of a pattern on a substrate or substrates after a step in a device manufacturing process are disclosed. In one arrangement, data representing a set of images is received. Each image represents a different instance of the pattern, wherein the pattern includes a plurality of pattern elements. The set of images are registered relative to each other to superimpose the instances of the pattern. The registration includes applying different weightings to two or more of the plurality of pattern elements, wherein the weightings control the extent to which each pattern element contributes to the registration of the set of images and each weighting is based on an expected variation of the pattern element to which the weighting is applied. Variation in the pattern is measured using the registered set of images.

Abstract: A substrate, including a substrate layer; and an etchable layer on the substrate layer, the etchable layer including a patterned region thereon or therein and including a blank region of sufficient size to enable a bulk etch rate of an etch tool for etching the blank region to be determined.