A lithographic apparatus configured to project a patterned beam of radiation onto a target portion of a substrate is disclosed. The apparatus includes a first radiation dose detector and a second radiation dose detector, each detector comprising a secondary electron emission surface configured to receive a radiation flux and to emit secondary electrons due to the receipt of the radiation flux, the first radiation dose detector located upstream with respect to the second radiation dose detector viewed with respect to a direction of radiation transmission, and a meter, connected to each detector, to detect a current or voltage resulting from the secondary electron emission from the respective electron emission surface.

Lithographic apparatus, and device manufacturing method

A new tracking technique is essentially “sourceless” in that it can be used anywhere with no set-up, yet it enables a much wider range of virtual environment-style navigation and interaction techniques than does a simple head-orientation tracker. A sourceless head orientation tracker is combined with a head-worn tracking device that tracks a hand-mounted 3D beacon relative to the head. The system encourages use of intuitive interaction techniques which exploit proprioception.

Self-referenced tracking

A pacing system for providing optimal hemodynamic cardiac function for parameters such as contractility (peak left ventricle pressure change during systole or LV+dp/dt), or stroke volume (aortic pulse pressure) using system for calculating atrio-ventricular delays for optimal timing of a ventricular pacing pulse. The system providing an option for near optimal pacing of multiple hemodynamic parameters. The system deriving the proper timing using electrical or mechanical events having a predictable relationship with an optimal ventricular pacing timing signal.

Cardiac pacing using adjustable atrio-ventricular delays

A liquid crystal panel according to an embodiment of the present invention includes: a liquid crystal cell; a first polarizer arranged on one side of the liquid crystal cell; a second polarizer arranged on another side of the liquid crystal cell; a positive A plate and a positive C plate arranged between the liquid crystal cell and the first polarizer; and an isotropic optical element arranged between the liquid crystal cell and the second polarizer, wherein the positive A plate is arranged between the first polarizer and the positive C plate.

Liquid crystal panel and liquid crystal display apparatus

The invention relates to a projection system, comprising a radiation source, an illumination system operable to illuminate a structured mask, and a projection objective for projecting an image of the mask structure onto a light-sensitive substrate, wherein said projection system comprises an optical system comprising an optical axis or a preferred direction given by the direction of a light beam propagating through the optical system; the optical system comprising a temperature compensated polarization-modulating optical element described by coordinates of a coordinate system, wherein one preferred coordinate of the coordinate system is parallel to the optical axis or parallel to said preferred direction; said temperature compensated polarization-modulating optical element comprising a first and a second polarization-modulating optical element, the first and/or the second polarization-modulating optical element comprising solid and/or liquid optically active material and a profile of effective optical thickness, wherein the effective optical thickness varies at least as a function of one coordinate different from the preferred coordinate of the coordinate system, in addition or alternative the first and/or the second polarization-modulating optical element comprises solid and/or liquid optically active material, wherein the effective optical thickness is constant as a function of at least one coordinate different from the preferred coordinate of the coordinate system; wherein the first polarization-modulating optical element comprises optically active material with a specific rotation of opposite sign compared to the optically active material of the second polarization-modulating optical element.

Polarization-modulating optical element

The invention features an interferometry system (10) that measures changes in the angular orientation of a measurement object (66) and that also includes at least one dynamic beam-steering assembly (60) The dynamic beam-steering assembly redirects one or more beams (15, 16) within the interferometry system in response to a change in the angular orientation of the measurement object In many embodiments, the presence of the dynamic beam-steering assembly permits the interferometry system to measure the angular orientation of the measurement object using only a single measurement beam to contact the measurement object Furthermore, in many embodiments, a control signal (76) derived from the measurement beam contacting the measurement object causes the beam-steering assembly to redirect a measurement beam to contact the measurement object at normal incidence When at such normal incidence, the interferometry system can calculate the angular orientation of the measurement object based on one or more interferometric signals derived from the measurement beam or based on the orientation of the beam-steering assembly itself

Interferometry system having a dynamic beam-steering assembly for measuring angle and distance

Apparatus and methods particularly suitable for use in electro-optical metrology and other applications to measure and monitor the refractive index of a gas in a measurement path and/or the change in optical path length of the measurement path due to the gas while the refractive index of the gas may be fluctuating due to turbulence or the like and/or the physical length of the measuring path may be changing. More specifically, the invention employs electronic frequency processing to provide measurements of dispersion of the refractive index, the dispersion being substantially proportional to the density of the gas, and/or measurements of dispersion of the optical path length, the dispersion of the optical path length being related to the dispersion of the refractive index and the physical length of the measurement path. The refractive index of the gas and/or the optical path length effects of the gas are subsequently computed from the measured dispersion of the refractive index and/or the measured dispersion of the optical path length, respectively. The information generated by the inventive apparatus is particularly suitable for use in interferometric distance measuring instruments (DMI) to compensate for errors related to refractive index of gas in a measurement path brought about by environmental effects and turbulence induced by rapid stage slew rates. In preferred embodiments, differential plane mirror interferometer architectures are utilized, the operating wavelengths are approximately harmonically related and may be monitored and/or controlled to meet precision requirements, heterodyne and superheterodyne processing are beneficially used, and phase redundancy is resolved.

Interferometer and method for measuring the refractive index and optical path length effects of air

The invention features interferometry systems that characterize cyclic errors. In many embodiments, the systems include a phase-shifting component (81), such as a phase shifter or frequency shifter, for introducing a variable and controlled phase between the reference and measurement beams of an interferometer (69). By analyzing the distance measurements of the interferometer (69) as a function of the introduced phase, an analyzer (27, 29) in the interferometry system can characterize the cyclic errors in the interferometer. Once the cyclic errors are characterized, the analyzer (27, 29) can directly correct the distance measurements to remove contributions from cyclic errors.

Systems and methods for characterizing and correcting cyclic errors in distance measuring and dispersion interferometry

The invention features interference signals for each of multiple Doppler shifts to thereby resolve nonlinearities, e.g., cyclic errors (90, 91, 92, 95), that may otherwise overlap spectrally with a dominant interference signal, and also interpolates the contributions of the nonlinearities to measurements at different doppler shifts. The time varying interference signal or the phase extracted from interference signal is Fourier transformed and at least some of the nonlinearities are associated with peaks in the square modulus of the Fourier transformed signal. The amplitude and phase of the Fourier transform at the frequency of each peak are used to quantify the nonlinearities. The quantified nonlinearities are used to correct optical pathlength measurements by the system.

Systems and methods for quantifying nonlinearities in interferometry systems

The invention features an interferometry system which includes at least one dynamic beam steering assembly for redirecting one or more beams within the interferometry system in response to changes in the angular orientation or position of the measurement object. A control circuit controls the beam steering assembly based on a signal derived from one or more beams within the interferometry system. The dynamic beam steering assembly can be incorporated into interferometry systems that measure displacement, angle, and/or dispersion. The interferometry systems can be advantageously incorporated into lithography systems used to fabricate integrated circuits and other semiconducting devices and beam writing systems used to fabricate lithography masks.

Henry A. Hill

Papers

Interferometry system having a dynamic beam-steering assembly for measuring angle and distance

Interferometer and method for measuring the refractive index and optical path length effects of air

Systems and methods for characterizing and correcting cyclic errors in distance measuring and dispersion interferometry

Systems and methods for quantifying nonlinearities in interferometry systems

Single-pass and multi-pass interferometery systems having a dynamic beam-steering assembly for measuring distance, angle, and dispersion