A method is proposed involving obtaining data regarding an expected focus offset during a patterning process due to topography of a region of a substrate surface. A modification of, e.g., a transmission or reflection of a region of a patterning device associated with the region of the substrate surface is determined based on the data. Using the patterning device modified according the determined modification during the patterning process mitigates an impact of the substrate topography on a parameter of the patterning process.

A method for vertical control of a lithography machine includes step 1, prior to a scanning exposure, controlling vertical measurement sensors to measure workpiece to obtain overall surface profile data of the workpiece; step 2, performing a global leveling based on the overall surface profile data of the workpiece; and step 3, during the scanning exposure of each exposure field, measuring a local surface profile of the workpiece in real time by the vertical measurement sensors and controlling at least one of a mask stage, a workpiece stage and a projection objective to move vertically according to a Z-directional height value, an Rx-directional tilt value and an Ry-directional tilt value corresponding to the local surface profile of the workpiece, to compensate for the local surface profile of the workpiece in real time, so that an upper surface of each exposure field coincides with a reference focal plane for the exposure field. This method enables flexible vertical control with high accuracy by providing multiple control options.

A lithographic apparatus includes a number of sensors for measuring positions of features on a substrate prior to applying a pattern. Each sensor includes an imaging optical system. Position measurements are extracted from pixel data supplied by an image detector in each sensor. The imaging optical system includes one or more light field modulating elements and the processor processes the pixel data as a light-field image to extract the position measurements. The data processor may derive from each light-field image a focused image of a feature on the substrate, measuring positions of several features simultaneously, even though the substrate is not at the same level below all the sensors. The processor can also include corrections to reduce depth dependency of an apparent position of the feature include a viewpoint correction. The data processor can also derive measurements of heights of features on the substrate.

In a method executed in an exposure apparatus, a focus control effective region and a focus control exclusion region are set based on an exposure map and a chip area layout within an exposure area. Focus-leveling data are measured over a wafer. A photo resist layer on the wafer is exposed with an exposure light. When a chip area of a plurality of chip areas of the exposure area is located within an effective region of a wafer, the chip area is included in the focus control effective region, and when a part of or all of a chip area of the plurality of chip areas is located on or outside a periphery of the effective region of the wafer, the chip area is included in the focus control exclusion region In the exposing, a focus-leveling is controlled by using the focus-leveling data measured at the focus control effective region.

A lithography apparatus and method is provided. The lithography apparatus includes at least two exposure devices and one substrate device. The substrate device includes a substrate stage and a substrate supported by the substrate stage. The at least two exposure devices are disposed in symmetry to each other above the substrate with respect to a direction for scanning exposure and configured to simultaneously create two exposure fields onto the substrate to expose the portions of the substrate within the exposure fields.

In immersion lithography after exposure of a substrate is complete, a detector is used to detect any residual liquid remaining on the substrate and/or substrate table.

Methods and associated apparatus for reconstructing a free-form geometry of a substrate, the method including: positioning the substrate on a substrate holder configured to retain the substrate under a retaining force that deforms the substrate from its free-form geometry; measuring a height map of the deformed substrate; and reconstructing the free-form geometry of the deformed substrate based on an expected deformation of the substrate by the retaining force and the measured height map.

Adaptive alignment methods and systems are disclosed. An adaptive alignment system may include a scanner configured to align a wafer and an analyzer in communication with the scanner. The analyzer may be configured to: recognize at least one defined analysis area; determine whether any perturbations exist within the analysis area; and in response to at least one perturbation determined to be within the analysis area, invoke a fall back alignment strategy or report the at least one perturbation to the scanner.

A Lithographic apparatus and method of controlling a lithographic process. A substrate is provided and a photosensitive layer is provided on a main surface of the substrate. The substrate includes a base section and a mesa section. In the base section the main surface is in a base plane. The mesa section protrudes from the base plane. A radiation beam scans the photosensitive layer. A local dose applied to a partial area of the photosensitive layer by the radiation beam includes a base dose component and a correction dose component. The correction dose component is a function of a distance between the partial area and a transition between the base section and the mesa section and at least partly compensates an effect of a defocus, which results from a height difference between the mesa section and the base section, on a critical dimension in the partial area.

The present disclosure provides a method of leveling a wafer in an exposure process. The wafer includes a plurality of regions. The wafer is loaded to an exposure system. The exposure system includes a control unit and a leveling module. The control unit of the exposure system obtains layout information of the reticle. The control unit of the exposure system assigns critical regions and non-critical regions to the regions on the wafer according to the layout information of the reticle.