A lithographic apparatus having a substrate table, a projection system, an encoder system, a measurement frame and a measurement system. The substrate table has a holding surface for holding a substrate. The projection system is for projecting an image on the substrate. The encoder system is for providing a signal representative of a position of the substrate table. The measurement system is for measuring a property of the lithographic apparatus. The holding surface is along a plane. The projection system is at a first side of the plane. The measurement frame is arranged to support at least part of the encoder system and at least part of the measurement system at a second side of the plane different from the first side.

Systems, apparatuses, and methods are provided for determining the alignment of a substrate. An example method can include emitting a multi-wavelength radiation beam including a first wavelength and a second wavelength toward a region of a surface of a substrate. The example method can further include measuring a first diffracted radiation beam indicative of first order diffraction at the first wavelength in response to an irradiation of the region by the multi-wavelength radiation beam. The example method can further include measuring a second diffracted radiation beam indicative of first order diffraction at the second wavelength in response to the irradiation of the region by the multi-wavelength radiation beam. Subsequently, the example method can include generating, based on the measured first set of photons and the measured second set of photons, an electronic signal for use in determining an alignment position of the substrate.

The invention provides a position sensor (300) which comprises an optical system (305,306) configured to provide measurement radiation (304) to a substrate (307). The optical system is arranged to receive at least a portion of radiation (309) diffracted by a mark (308) provided on the substrate. A processor (313) is applied to derive at least one position-sensitive signal (312) from the received radiation. The measurement radiation comprises at least a first and a second selected radiation wavelength. The selection of the at least first and second radiation wavelengths is based on a position error swing-curve model.

An interferometer system including: an optical system arranged to split a radiation beam from a laser source into a first beam along a first optical path and a second beam along a second optical path, and recombine the first beam and the second beam to a recombined beam, a detector to receive the recombined beam and to provide a detector signal based on the received recombined beam, and a processing unit, wherein a first optical path length of the first optical path and a second optical path length of the second optical path have an optical path length difference, and wherein the processing unit is arranged to determine a mode hop of the laser source on the basis of a phase shift in the detector signal.

Two pairs of alignment targets (one aligned, one misaligned by a bias distance) are formed on different masks to produce a first pair of conjugated interference patterns. Other pairs of alignment targets are also formed on the masks to produce a second pair of conjugated interference patterns that are inverted the first. Misalignment of the dark and light regions of the first interference patterns and the second interference patterns in both pairs of conjugated interference patterns is determined when patterns formed using the masks are overlaid. A magnification factor (of the interference pattern misalignment to the target misalignment) is calculated as a ratio of the difference of misalignment of the relatively dark and relatively light regions in the pairs of interference patterns, over twice the bias distance. The interference pattern misalignment is divided by the magnification factor to produce a self-referenced and self-calibrated target misalignment amount, which is then output.

A substrate stage apparatus provided with: a substrate holder that can be moved in a plane including an X-axis and a Y-axis; a head unit that can be moved synchronously with the substrate holder along the Y-axis; an encoder system for measuring substrate position, the system including a scale disposed on the substrate holder, and heads disposed on the head unit, and acquiring the X-axis direction and the Y-axis direction position information of the substrate holder on the basis of the output of the heads; an encoder system for measuring head-unit position, the system acquiring the Y-axis direction position information of the head unit; and a position control system that controls the position of the substrate holder within the XY plane on the basis of the output of the encoder system for measuring substrate position and the encoder system for measuring head-unit position.

An interferometer system including: an optical system arranged to split a radiation beam from a laser source into a first beam along a first optical path and a second beam along a second optical path, and recombine the first beam and the second beam to a recombined beam, a detector to receive the recombined beam and to provide a detector signal based on the received recombined beam, and a processing unit, wherein a first optical path length of the first optical path and a second optical path length of the second optical path have an optical path length difference, and wherein the processing unit is arranged to determine a mode hop of the laser source on the basis of a phase shift in the detector signal.

Apparatus for, and method of, measuring a parameter of an alignment mark on a substrate in which an optical system is arranged to receive at least one diffraction order from the alignment mark and the diffraction order is modulated at a pupil or a wafer conjugate plane of the optical system, a solid state optical device is arranged to receive the modulated diffraction order, and a spectrometer is arranged to receive the modulated diffraction order from the solid state optical device and to determine an intensity of one or more spectral components in the modulated diffraction order.

An alignment apparatus includes an illumination system configured to direct one or more illumination beams towards an alignment target and receive the diffracted beams from the alignment target. The alignment apparatus also includes a self-referencing Interferometer configured to generate two diffraction sub-beams, wherein the two diffraction sub-beams are orthogonally polarized, rotated 180 degrees with respect to each other around an alignment axis, and spatially overlapped. The alignment apparatus further includes a beam analyzer configured to generate interference between the overlapped components of the diffraction sub-beams and produce two orthogonally polarized optical branches, and a detection system configured to determine a position of the alignment target based on light intensity measurement of the optical branches, wherein the measured light intensity is temporally modulated by a phase modulator.

According to one embodiment, a position measuring apparatus includes a substrate holding part, a projection part, a liquid supply part, an imaging part, a position measuring part, and a control unit. The substrate holding part is configured to hold a substrate including at least part of a circuit pattern. The projection part is configured to irradiate the substrate held on the substrate holding part with illumination light, and to transmit reflected light from the substrate, of the illumination light radiated on the substrate. The liquid supply part is configured to supply a liquid into a space between the substrate held on the substrate holding part and the projection part. The imaging part is configured to receive the reflected light transmitted through the projection part, and to generate an image signal based on the reflected light. The position measuring part is configured to obtain positional information on a position of the substrate holding part. The control unit is configured to determine a coordinate position of the at least part of a circuit pattern in the substrate, on a basis of the positional information and the image signal.