Abstract: An optical element includes Strontium tetraborate SrB4O7 (SBO) crystal plates that are cooperatively configured to create a periodic structure for quasi-phase-matching (QPM) is used in the final frequency converting stage of a laser assembly to generate laser output light having a wavelength in the range of 125 nm to 183 nm. One or more fundamental light beams having fundamental wavelengths between 1 and 1.1 ?m are doubled and/or summed using multiple intermediate frequency conversion stages to generate one or more intermediate light beam frequencies (e.g., second through eighth harmonics, or sums thereof), and then the final frequency converting stage utilizes the optical element to either double a single intermediate light beam frequency or to sum two intermediate light beam frequencies to generate the desired laser output light at high power and photon energy levels. A method and inspection system incorporating the laser assembly is also described.

Abstract: A tunable laser assembly uses a fundamental wavelength between 1 ?m and 1.1 ?m to alternately generate laser output light at two or more output wavelengths within the range of 184 nm to 200 nm by directing the fundamental light through different regions of a fan-out periodically poled nonlinear crystal to generate corresponding different down-converted signals, and using different nonlinear summing crystals to mix the different down-converted signals with a fifth harmonic of the fundamental wavelength. Each nonlinear summing crystal has a crystal axis aligned at an angle relative to the light propagation direction to facilitate the efficient transmission and summing of the fifth harmonic with an associated down-converted signal.

Abstract: A light modulated electron source utilizes a photon-beam source to modulate the emission current of an electron beam emitted from a silicon-based field emitter. The field emitter's cathode includes a protrusion fabricated on a silicon substrate and having an emission tip covered by a coating layer. An extractor generates an electric field that attracts free electrons toward the emission tip for emission as part of the electron beam. The photon-beam source generates a photon beam including photons having an energy greater than the bandgap of silicon, and includes optics that direct the photon beam onto the emission tip, whereby each absorbed photon creates a photo-electron that combines with the free electrons to enhance the electron beam's emission current. A controller modulates the emission current by controlling the intensity of the photon beam applied to the emission tip. A monitor measures the electron beam and provides feedback to the controller.

Abstract: An inspection system may include an illumination source to generate an illumination beam, illumination optics to direct the illumination beam to a sample at an off-axis angle along an illumination direction, and collection optics to collect scattered light from the sample in a dark-field mode, where the scattered light from the sample includes surface haze associated with light scattered from a surface of the sample, and where at least a at least a portion of the surface haze has elliptical polarizations. The system may further include pupil-plane optics to convert the polarizations of the surface haze across the pupil to linear polarization that is aligned parallel to a selected haze orientation direction. The system may include a linear polarizer to reject the surface haze aligned parallel to this haze orientation direction and a detector to generate a dark-field image of the sample based on light passed by the linear polarizer.

Abstract: A broadband ultraviolet illumination source for a characterization system is disclosed. The broadband ultraviolet illumination source includes an enclosure having one or more walls, the enclosure configured to contain a gas, and a plasma discharge device based on a graphene-dielectric-semiconductor (GOS) planar-type structure. The GOS structure includes a silicon substrate having a top surface, a dielectric layer disposed on the top surface of the silicon substrate, and at least one layer of graphene disposed on a top surface of the dielectric layer. A metal contact may be formed on the top surface of the graphene layer. The GOS structure has several advantages for use in an illumination source, such as low operating voltage (below 50 V), planar surface electron emission, and compatibility with standard semiconductor processes. The broadband ultraviolet illumination source further includes electrodes placed inside the enclosure or magnets placed outside the enclosure to increase the current density.

Abstract: A light modulated electron source utilizes a photon-beam source to modulate the emission current of an electron beam emitted from a silicon-based field emitter. The field emitter's cathode includes a protrusion fabricated on a silicon substrate and having an emission tip covered by a coating layer. An extractor generates an electric field that attracts free electrons toward the emission tip for emission as part of the electron beam. The photon-beam source generates a photon beam including photons having an energy greater than the bandgap of silicon, and includes optics that direct the photon beam onto the emission tip, whereby each absorbed photon creates a photo-electron that combines with the free electrons to enhance the electron beam's emission current. A controller modulates the emission current by controlling the intensity of the photon beam applied to the emission tip. A monitor measures the electron beam and provides feedback to the controller.

Abstract: Back-illuminated DUV/VUV/EUV radiation or charged particle image sensors are fabricated using a method that utilizes a plasma atomic layer deposition (plasma ALD) process to generate a thin pinhole-free pure boron layer over active sensor areas. Circuit elements are formed on a semiconductor membrane's frontside surface, and then an optional preliminary hydrogen plasma cleaning process is performed on the membrane's backside surface. The plasma ALD process includes performing multiple plasma ALD cycles, with each cycle including forming an adsorbed boron precursor layer during a first cycle phase, and then generating a hydrogen plasma to convert the precursor layer into an associated boron nanolayer during a second cycle phase. Gasses are purged from the plasma ALD process chamber after each cycle phase. The plasma ALD cycles are repeated until the resulting stack of boron nanolayers has a cumulative stack height (thickness) that is equal to a selected target thickness.

Abstract: Strontium tetraborate is used as an optical coating material for optical components utilized in semiconductor inspection and metrology systems to take advantage of its high refractive indices, high optical damage threshold and high microhardness in comparison to conventional optical materials. At least one layer of strontium tetraborate is formed on the light receiving surface of an optical component's substrate such that its thickness serves to increase or decrease the reflectance of the optical component. One or multiple additional coating layers may be placed on top of or below the strontium tetraborate layer, with the additional coating layers consisting of conventional optical materials. The thicknesses of the additional layers may be selected to achieve a desired reflectance of the optical component at specific wavelengths. The coated optical component is used in an illumination source or optical system utilized in a semiconductor inspection system, a metrology system or a lithography system.

Abstract: Strontium tetraborate can be used as an optical material. Strontium tetraborate exhibits high refractive indices, high optical damage threshold, and high microhardness. The transmission window of strontium tetraborate covers a very broad range of wavelengths, from 130 nm to 3200 nm, making the material particularly useful at VUV wavelengths. An optical component made of strontium tetraborate can be incorporated in an optical system, such as a semiconductor inspection system, a metrology system, or a lithography system. These optical components may include mirrors, lenses, lens arrays, prisms, beam splitters, windows, lamp cells or Brewster-angle optics.

Abstract: An optical element includes Strontium tetraborate SrB4O7 (SBO) crystal plates that are cooperatively configured to create a periodic structure for quasi-phase-matching (QPM) is used in the final frequency converting stage of a laser assembly to generate laser output light having a wavelength in the range of 125 nm to 183 nm. One or more fundamental light beams having fundamental wavelengths between 1 and 1.1 ?m are doubled and/or summed using multiple intermediate frequency conversion stages to generate one or more intermediate light beam frequencies (e.g., second through eighth harmonics, or sums thereof), and then the final frequency converting stage utilizes the optical element to either double a single intermediate light beam frequency or to sum two intermediate light beam frequencies to generate the desired laser output light at high power and photon energy levels. A method and inspection system incorporating the laser assembly is also described.

Abstract: Strontium tetraborate can be used as an optical material. Strontium tetraborate exhibits high refractive indices, high optical damage threshold, and high microhardness. The transmission window of strontium tetraborate covers a very broad range of wavelengths, from 130 nm to 3200 nm, making the material particularly useful at VUV wavelengths. An optical component made of strontium tetraborate can be incorporated in an optical system, such as a semiconductor inspection system, a metrology system, or a lithography system. These optical components may include mirrors, lenses, lens arrays, prisms, beam splitters, windows, lamp cells or Brewster-angle optics.

Abstract: A nonlinear crystal including stacked Strontium tetraborate SrB4O7 (SBO) crystal plates that are cooperatively configured to create a periodic structure for quasi-phase-matching (QPM) is used in the final frequency converting stage of a laser assembly to generate laser output light having a wavelength in the range of 125 nm to 183 nm. One or more fundamental light beams having fundamental wavelengths between 1 and 1.1 ?m are doubled and/or summed using multiple intermediate frequency conversion stages to generate one or more intermediate light beam frequencies (e.g., second through eighth harmonics, or sums thereof), and then the final frequency converting stage utilizes the nonlinear crystal to either double a single intermediate light beam frequency or to sum two intermediate light beam frequencies to generate the desired laser output light at high power and photon energy levels. A method and inspection system incorporating the laser assembly is also described.

Abstract: A laser system includes a nonlinear optical (NLO) crystal, wherein the NLO crystal is annealed within a selected temperature range. The NLO crystal is passivated with at least one of hydrogen, deuterium, a hydrogen-containing compound or a deuterium-containing compound to a selected passivation level. The system further includes at least one light source, wherein at least one light source is configured to generate light of a selected wavelength and at least one light source is configured to transmit light through the NLO crystal. The system further includes a crystal housing unit configured to house the NLO crystal.

Abstract: A nonlinear crystal including stacked Strontium tetraborate SrB4O7 (SBO) crystal plates that are cooperatively configured to create a periodic structure for quasi-phase-matching (QPM) is used in the final frequency converting stage of a laser assembly to generate laser output light having a wavelength in the range of 125 nm to 183 nm. One or more fundamental light beams having fundamental wavelengths between 1 and 1.1 ?m are doubled and/or summed using multiple intermediate frequency conversion stages to generate one or more intermediate light beam frequencies (e.g., second through eighth harmonics, or sums thereof), and then the final frequency converting stage utilizes the nonlinear crystal to either double a single intermediate light beam frequency or to sum two intermediate light beam frequencies to generate the desired laser output light at high power and photon energy levels. A method and inspection system incorporating the laser assembly is also described.

Abstract: The passivation of a nonlinear optical crystal for use in an inspection tool includes growing a nonlinear optical crystal in the presence of at least one of fluorine, a fluoride ion and a fluoride-containing compound, mechanically preparing the nonlinear optical crystal, performing an annealing process on the nonlinear optical crystal and exposing the nonlinear optical crystal to a hydrogen-containing or deuterium-containing passivating gas.

Abstract: An image sensor is fabricated by first heavily p-type doping the thin top monocrystalline silicon substrate of an SOI wafer, then forming a relatively lightly p-doped epitaxial layer on a top surface of the top silicon substrate, where p-type doping levels during these two processes are controlled to produce a p-type dopant concentration gradient in the top silicon substrate. Sensing (circuit) elements and associated metal interconnects are fabricated on the epitaxial layer, then the handling substrate and oxide layer of the SOI wafer are at least partially removed to expose a lower surface of either the top silicon substrate or the epitaxial layer, and then a pure boron layer is formed on the exposed lower surface. The p-type dopant concentration gradient monotonically decreases from a maximum level near the top-silicon/epitaxial-layer interface to a minimum concentration level at the epitaxial layer's upper surface.

Abstract: An image sensor utilizes a pure boron layer and a second epitaxial layer having a p-type dopant concentration gradient to enhance sensing DUV, VUV or EUV radiation. Sensing (circuit) elements and associated metal interconnects are fabricated on an upper surface of a first epitaxial layer, then the second epitaxial layer is formed on a lower surface of the first epitaxial layer, and then a pure boron layer is formed on the second epitaxial layer. The p-type dopant concentration gradient is generated by systematically increasing a concentration of p-type dopant in the gas used during deposition/growth of the second epitaxial layer such that a lowest p-type dopant concentration of the second epitaxial layer occurs immediately adjacent to the interface with the first epitaxial layer, and such that a highest p-type dopant concentration of the second epitaxial layer occurs immediately adjacent to the interface with pure boron layer.

Abstract: An image sensor for electrons or short-wavelength light includes a semiconductor membrane, circuit elements formed on one surface of the semiconductor membrane, and a pure boron layer on the other surface of the semiconductor membrane. The circuit elements are connected by metal interconnects comprising a refractory metal. An anti-reflection or protective layer may be formed on top of the pure boron layer. This image sensor has high efficiency and good stability even under continuous use at high flux for multiple years. The image sensor may be fabricated using CCD (charge coupled device) or CMOS (complementary metal oxide semiconductor) technology. The image sensor may be a two-dimensional area sensor, or a one-dimensional array sensor.

Abstract: A broadband ultraviolet illumination source for a characterization system is disclosed. The broadband ultraviolet illumination source includes an enclosure having one or more walls, the enclosure configured to contain a gas, and a plasma discharge device based on a graphene-dielectric-semiconductor (GOS) planar-type structure. The GOS structure includes a silicon substrate having a top surface, a dielectric layer disposed on the top surface of the silicon substrate, and at least one layer of graphene disposed on a top surface of the dielectric layer. A metal contact may be formed on the top surface of the graphene layer. The GOS structure has several advantages for use in an illumination source, such as low operating voltage (below 50 V), planar surface electron emission, and compatibility with standard semiconductor processes. The broadband ultraviolet illumination source further includes electrodes placed inside the enclosure or magnets placed outside the enclosure to increase the current density.

Abstract: Methods and systems for realizing a high radiance x-ray source based on a high density electron emitter array are presented herein. The high radiance x-ray source is suitable for high throughput x-ray metrology and inspection in a semiconductor fabrication environment. The high radiance X-ray source includes an array of electron emitters that generate a large electron current focused over a small anode area to generate high radiance X-ray illumination light. In some embodiments, electron current density across the surface of the electron emitter array is at least 0.01 Amperes/mm2, the electron current is focused onto an anode area with a dimension of maximum extent less than 100 micrometers, and the spacing between emitters is less than 5 micrometers. In another aspect, emitted electrons are accelerated from the array to the anode with a landing energy less than four times the energy of a desired X-ray emission line.