A lithographic apparatus (LA) applies a pattern to a substrate (W). The lithographic apparatus includes a height sensor (LS), a substrate positioning subsystem, and a controller configured for causing the height sensor to measure the height (h) of the substrate surface at locations across the substrate. The measured heights are used to control the focusing of one or more patterns applied to the substrate. The height h is measured relative to a reference height (zref). The height sensor is operable to vary the reference height (zref), which allows a wider effective range of operation. Specifications for control of the substrate height during measurement can be relaxed. The reference height can be varied by moving one or more optical elements (566, 572, 576, 504 and/or 512) within the height sensor, or moving the height sensor. An embodiment without moving parts includes a multi-element photodetector (1212).

A position encoder for monitoring relative movement between a first object and a second object includes a grating that is coupled to the first object, and an image sensor assembly that is coupled to the second object. The image sensor includes a first image sensor; a second image sensor that is spaced apart from the first image sensor; an optical element that includes a first optical surface and a second optical surface that is spaced apart from the first optical surface; and an illumination system. The illumination system directs an illumination beam at the optical element to create (i) a first reference beam that is reflected by the first optical surface and directed at the first image sensor, (ii) a second reference beam that is reflected by the second optical surface and directed at the second image sensor, and (iii) a transmitted beam that is transmitted through the optical element and is directed at and impinges on the grating to create a first measurement beam that is diffracted by the grating and directed at the first image sensor, and a second measurement beam that is diffracted by the grating and directed at the second image sensor.

A self-calibrating overlay metrology system may receive device overlay data from device targets on a sample, determine preliminary device overlay measurements for the device targets including device-scale features using an overlay recipe with the device overlay data as inputs, receive assist overlay data from sets of assist targets on the sample including device-scale features, where a particular set of assist targets includes one or more target pairs formed with two overlay targets having programmed overlay offsets of a selected value with opposite signs along a particular measurement direction. The system may further determine self-calibrating assist overlay measurements for the sets of assist targets based on the assist overlay data, where the self-calibrating assist overlay measurements are linearly proportional to overlay on the sample, and generate corrected overlay measurements for the device targets by adjusting the preliminary device overlay measurements based on the self-calibrating assist overlay measurements.

A substrate treating method includes measuring an alignment state of a substrate placed on a hand of a transfer unit that transfers the substrate, transferring the substrate to a substrate alignment unit by the transfer unit when the alignment state of the substrate is faulty, aligning a location of the substrate by the substrate alignment unit, and temporarily correcting the location of the substrate before the substrate is loaded on the substrate alignment unit when it is measured in the measuring of the alignment state that the alignment state of the substrate exceeds a sensor reading range.

An object holder configured to support an object, the object holder including: a core body comprising a plurality of burls having distal ends in a support plane for supporting the object; and an electrostatic sheet between the burls, the electrostatic sheet comprising an electrode sandwiched between dielectric layers, wherein the electrostatic sheet is bonded to the core body by a bonding material having a thickness of at least 100 nm.

A management apparatus includes a learning device. The learning device is configured to, in a case where a reward obtained from a control result of a controlled object by a controller configured to control the controlled object using a neural network, for which a parameter value is decided by reinforcement learning, does not satisfy a predetermined criterion, redecide the parameter value by reinforcement learning.

A position measurement system including a first interferometer and a second interferometer arranged to determine a distance of the object in a first direction when the object is in a first measurement area by emitting beams onto a target surface of the object. The position measurement system further has a third interferometer and a fourth interferometer arranged to determine a distance of the object in the first direction when the object is in a second measurement area by emitting beams onto the target surface of the object. An arrangement of relative positions in a second direction of beams spots impinging on the target surface from the beams emitted by the first and second interferometers is different from an arrangement of relative positions in the second direction of beams spots impinging on the target surface from the beams emitted by the third and fourth interferometers.

According to one embodiment, a registration mark includes a first step portion and a second step portion. The first step portion includes a plurality of first steps which descend step by step in a first direction from a surface of a substrate or a layer formed on the substrate. The second step portion includes a plurality of second steps which descend step by step from the surface in a second direction different from the first direction and have the same number as the number of the plurality of first steps, is spaced apart from the first step portion, and is disposed rotationally symmetrically to the first step portion.

In corner sections of first to fourth quadrants whose origin point is a center of an upper surface of a stage, three each of two-dimensional heads are provided. The three each of two-dimensional heads include one first head and two second heads. The stage is driven, while measuring a position of the stage using three first heads that face a two-dimensional grating of a scale plate provided above the stage from the four first heads, and during the driving, difference data of measurement values of the two second heads with respect to the first head in a measurement direction are taken in for head groups to which the three first heads belong, respectively, and using the difference data, grid errors are calibrated.

An apparatus for use in a metrology process or a lithographic process, the apparatus including: an object support module adapted to hold an object; and a first gas shower arranged on a first side of the object support module and adapted to emit a gas with a first velocity in a first gas direction which is a horizontal direction to cause a net gas flow in the apparatus to be a substantially horizontal gas flow in the first gas direction at least above the object support module.