An apparatus and method are disclosed for actinic inspection of semiconductor masks intended for extended ultraviolet (EUV) lithography, or similar objects, with feature sizes less than 100 nm. The approach uses a coherent light source with wavelength less than 120 nm. Inside a vacuum system, an optical system directs the light to an object, i.e., the mask or mask blank, and directs the resulting reflected or transmitted light to an imaging sensor. A computational system processes the imaging sensor data to generate phase and amplitude images of the object. The preferred imaging modality, a form of digital holography, produces images of buried structures and phase objects, as well as amplitude or reflectance images, with nanometer resolution less than or equal to the feature size of the mask.

The invention relates to the field of quantum radio physics and is the solid-state quantum generator of nanometer range electromagnetic radiation. It may be widely used in engineering, nanotechnology, physics, biology, chemistry and medicine. The claimed device comprises at least two electric power adjustment devices, at least one phase shifting device, at least one electromagnetic wave emitter, at least two exciting inductors and an excited inductor. It is configured to adjust electrical power in the first and second exciting inductors, allowing to receive electrical signals with equal amplitudes in them.

An optical assembly guides an output beam of a free electron laser to a downstream illumination-optical assembly of an EUV projection exposure apparatus. The optical assembly has first and a second GI mirrors, each with a structured reflection surface to be impinged upon by the output beam. A first angle of incidence on the first GI mirror is between one mrd and 10 mrad. A maximum first scattering angle is produced, amounting to between 50% and 100% of the first angle of incidence. A second angle of incidence on the second GI mirror is at least twice as large as the first angle of incidence. A maximum second scattering angle of the output beam amounts to between 30% and 100% of the second angle of incidence. The two planes of incidence on the two GI mirrors include an angle with respect to one another that is greater than 45.

A radiation sensor apparatus for determining a position and/or power of a radiation beam, the radiation sensor apparatus including a chamber to contain a gas, one or more sensors, and a processor. The chamber has a first opening and a second opening such that a radiation beam can enter the chamber through the first opening, propagate through the chamber generally along an axis, and exit the chamber through the second opening. Each of the one or more sensors is arranged to receive and detect radiation emitted from a region of the chamber around the axis. The processor is operable to use the radiation detected by the one or more sensors to determine a position and/or power of the radiation beam.

A method of patterning lithographic substrates, the method including using a free electron laser to generate EUV radiation and delivering the EUV radiation to a lithographic apparatus which projects the EUV radiation onto lithographic substrates, wherein the method further includes reducing fluctuations in the power of EUV radiation delivered to the lithographic substrates by using a feedback-based control loop to monitor the free electron laser and adjust operation of the free electron laser accordingly.

A helical superconducting undulator includes a cylindrical magnetic core through which a bore hole allows the passage of charged particles. A single superconducting wire wraps the magnetic core guided by helical flights and cylindrical protrusions, to create interleaved helical windings on the magnetic core. An electrical current may be supplied to the superconducting wire to generate a periodic helical magnetic field in the bore. The helical superconducting undulator also includes a strong-back enclosure that acts as an epoxy mold during epoxy impregnation, a structural support to ensure straightness of the undulator after epoxy impregnation, and assists in cooling and thermal control of the magnetic core and superconducting wire during device operation.

An undulator is adapted to a synchrotron storage ring or free electron lasers (FEL), especially to an undulator capable of switching polarization mode rapidly. In comparison with the EPU (elliptically polarized undulator) of APPLE II (Advanced Planar Polarized Light Emitter II) which conceived by Dr. S. Sasaki, the provided undulator does not use mechanical transmission mechanisms to drive the four magnetic pole arrays composed of permanent magnets. Hence, the polarization mode can be switched rapidly. Moreover, a polarization method of electron beam is also provided.

Orbital debris removal (ODR) systems under the present approach may use a ground- or surface-based FEL and mirror system with sufficient power and both spatial and temporal resolution to both locate Category II OD (1 cm to 10 cm diameter) in low Earth orbit (LEO, 160 to 2000 km altitude) and remove these objects from orbit. Locating the Category II OD is performed by having the light beam from an FEL and its beam director scan a volume of space of interest and then observing the light reflected from the OD. Removing the OD may include heating the OD to a sufficiently high temperature to evaporate the OD, changing the orbit of the OD such as to lower the perigee, or both. Megawatt-class MOPA FELs for, inter alia, removing OD, are described.

The present invention allows more freely setting of the polarization direction of illumination light on an illumination surface of an exposure device. A beam transmission system (121) that transmits, to an exposure device (130), a linearly polarized optical beam (L) output from a free electron laser device (10) includes: an optical beam splitting unit (50) configured to split the optical beam (L) into a first optical beam (L1) and a second optical beam (L2); and a first polarization direction rotating unit (51) configured to rotate the linear polarization direction of the first optical beam (L1).

An electron beam transport system for controlling the position of two different electron beams comprises: a main electron beam transport module; a first input electron beam transport module; a second input electron beam transport module; and a controller. The main electron beam transport module comprises a beam monitoring device disposed at a measurement position. The first input electron beam transport module comprises a first actuator for applying a perturbation to a transverse position of a first electron beam at a first actuation point. The second input electron beam transport module comprises a second actuator for applying a perturbation to a transverse position of a second electron beam at a second actuation point. The controller is operable to receive a signal from the beam monitoring device and to send control signals to the first actuator and the second actuator. The controller is operable to determine a first quantity indicative of a difference in a transverse position of the first and second electron beams and a second quantity indicative of an average transverse position of the first and second electron beams. The controller is further operable to control the trajectories of the first and second electron beams independently by implementing a first control loop that iteratively attempts to reduce the first quantity by using the first actuator to perturb a trajectory of the first electron beam, and a second control loop that iteratively perturbs a trajectory of the second electron beam using the second actuator such that the average transverse position of the two different electron beams moves towards a desired transverse position.