A method of optimizing an apparatus for multi-stage processing of product units such as wafers, the method includes: receiving object data representing one or more parameters measured across the product units and associated with different stages of processing of the product units; and determining fingerprints of variation of the object data across the product units, the fingerprints being associated with different respective stages of processing of the product units. The fingerprints may be determined by decomposing the object data into components using principal component analysis for each different respective stage; analyzing commonality of the fingerprints through the different stages to produce commonality results; and optimizing an apparatus for processing product units based on the commonality results.

Metrology target design methods and verification targets are provided. Methods include using OCD data related to designed metrology target(s) as an estimation of a discrepancy between a target model and a corresponding actual target on a wafer, and adjusting a metrology target design model to compensate for the estimated discrepancy. The dedicated verification targets may include overlay target features and be size optimized to be measurable by an OCD sensor, to enable compensation for inaccuracies resulting from production process variation. Methods also include modifications to workflows between manufacturers and metrology vendors which provide enabled higher fidelity metrology target design models and ultimately higher accuracy of metrology measurements.

An extreme ultraviolet light generation device includes: a target supply unit including a nozzle through which a target substance in a liquid form is output into a chamber; a piezoelectric element configured to vibrate the nozzle under a droplet connection condition to regularly generate a droplet of the target substance; and a control unit configured to perform search processing of changing a drive condition of the piezoelectric element to search for a drive condition of the piezoelectric element corresponding to the droplet connection condition and configured to set a drive condition of the piezoelectric element used for generation of extreme ultraviolet light based on a result of the search processing. The control unit preliminarily drives the piezoelectric element before performing the search processing and starts the search processing after performing the preliminary drive.

A projection system model is configured to predict optical aberrations of a projection system based upon a set of projection system characteristics and to determine and output a set of optical element adjustments based upon a merit function. The merit function comprises a set of parameters and corresponding weights. The method comprises receiving an initial merit function and executing an optimization algorithm to determine a second merit function. The optimization algorithm scores different merit functions based upon projection system characteristics of a projection system adjusted according to the output of the projection system model using a merit function having that set of parameters and weights.

A lithography system is provided and includes a light source device configured to emit a processing light beam onto the semiconductor wafer, to generate a penetrating light beam and a reflected light beam. The lithography system further includes a detecting module having a first detector and a second detector. The first detector is configured to receive the penetrating light beam to generate first power data, and the second detector is configured to receive the reflected light beam to generate second power data. The lithography system also includes a monitoring device configured to calculate absorbed power data of the semiconductor wafer according to the first power data, the second power data and reference power data of a reference light beam and configured to compensate for a pattern formed on the semiconductor wafer resulting from the processing light beam according to the absorbed power data and reference information.

A method for automatic inline detection and wafer disposition includes the following steps. An exposure process is performed to wafers in an exposure apparatus. A virtual inspection is performed based on log files of the exposure process. A wafer automatic disposition is performed according to a result of the virtual inspection. An automatic inline detection and wafer disposition system includes a first computer system coupled to an exposure apparatus and a second computer system coupled to the first computer system. The exposure apparatus is configured to perform an exposure process to wafers, and the first computer system is configured to perform a virtual inspection based on log files of the exposure process. The second computer system is configured to receive a result of the virtual inspection and perform a wafer automatic disposition according to the result of the virtual inspection.

Metrology target design methods and verification targets are provided. Methods comprise using OCD data related to designed metrology target(s) as an estimation of a discrepancy between a target model and a corresponding actual target on a wafer, and adjusting a metrology target design model to compensate for the estimated discrepancy. The dedicated verification targets may comprise overlay target features and be size optimized to be measureable by an OCD sensor, to enable compensation for inaccuracies resulting from production process variation. Methods also comprise modifications to workflows between manufacturers and metrology vendors which provide enable higher fidelity metrology target design models and ultimately higher accuracy of metrology measurements.

A polarized image acquisition apparatus includes a division type half-wave plate, located opposite to the mask substrate with respect to an objective lens and near an objective lens pupil position, to arrange P and S polarized waves of the transmitted light having passed through the objective lens to be mutually orthogonal, a Rochon prism to separate trajectories of P and S polarized waves, an imaging lens to form images of P and S polarized waves having passed through the Rochon prism at image formation positions different from each other, a mirror, in a case where one of P and S polarized waves is focused/formed at one of the different image formation positions, to reflect the other wave at the other position, a first sensor to capture an image of one of P and S polarized waves, and a second sensor to capture an image of the other wave.

A method for quantifying the effect of pupil function variations on a lithographic effect within a lithographic apparatus is disclosed. The method comprises: determining a discrete, two-dimensional sensitivity map in a pupil plane of the lithographic apparatus, wherein the lithographic effect is given by the inner product of said sensitivity map with a discrete, two-dimensional pupil function variation map of a radiation beam in the pupil plane. The pupil plane of a lithographic apparatus generally refers to the exit pupil of a projection system of the lithographic apparatus. Pupil function variations may comprise: relative phase variations within the pupil plane and/or relative intensity variations within the pupil plane.

A method and associated computer program for predicting an electrical characteristic of a substrate subject to a process. The method includes determining a sensitivity of the electrical characteristic to a process characteristic, based on analysis of electrical metrology data including electrical characteristic measurements from previously processed substrates and of process metrology data including measurements of at least one parameter related to the process characteristic measured from the previously processed substrates; obtaining process metrology data related to the substrate describing the at least one parameter; and predicting the electrical characteristic of the substrate based on the sensitivity and the process metrology data.