Abstract: Methods and apparatus for determining a focus of a projection system are disclosed. In one arrangement, a method includes obtaining first data derived from a first measurement of one or more selected properties of a target pattern formed on a substrate by exposing the substrate using the projection system. The first measurement is performed before the substrate is etched based on the target pattern. The method further includes obtaining second data derived from a second measurement of the one or more selected properties of the target pattern. The second measurement is performed after the substrate is etched based on the target pattern. The method further includes determining the focus of the projection system using the first data and the second data.

Abstract: A method of determining a characteristic of a guiding template for guiding self-assembly of block copolymer to form an entirety of a design layout, or a portion thereof, including a plurality of design features, each design feature including one or more elemental features, the method including selecting a characteristic of a guiding template for each of the one or more elemental features of the plurality of design features from a database or a computer readable non-transitory medium, the database or the computer readable non-transitory medium storing a characteristic of a guiding template for each of the one or more elemental features, and determining the characteristic of the guiding template to form the entirety of the design layout, or the portion thereof, by combining the selected characteristic of the guiding template for the one or more elemental features for each of the plurality of design features.

Abstract: A method of design or verification for a self-assemblable block copolymer feature, the block copolymer feature including a first domain having a first polymer type and a second domain having a second polymer type, the method including, based on the length of the second polymer type or on an uncertainty in position of the first domain within the block copolymer feature calculated based on the length of the second polymer type, adjusting a parameter of the self-assembly process of a block copolymer feature or verifying a placement of a block copolymer feature.