Abstract: A laser for generating an output wavelength of approximately 193.4 nm includes a fundamental laser, an optical parametric generator, a fourth harmonic generator, and a frequency mixing module. The optical parametric generator, which is coupled to the fundamental laser, can generate a down-converted signal. The fourth harmonic generator, which may be coupled to the optical parametric generator or the fundamental laser, can generate a fourth harmonic. The frequency mixing module, which is coupled to the optical parametric generator and the fourth harmonic generator, can generate a laser output at a frequency equal to a sum of the fourth harmonic and twice a frequency of the down-converted signal.

Abstract: An exemplary illumination source for an inspection system includes a pulsed seed laser having a wavelength of approximately 1104 nm and a continuous wave, Raman seed laser having a wavelength of approximately 1160 nm. An optical coupler can combine outputs of the pulsed seed laser and the continuous wave, Raman seed laser. Pre-amplification stages can receive an output of the optical coupler. A power amplifier can receive an output of the pre-amplification stages. A sixth harmonic can be generated using the amplified, combined wavelength. Systems for inspecting a specimen such as a reticle, photomask or wafer can include one of the illumination sources described herein.

Abstract: A laser system for semiconductor inspection includes a fiber-based fundamental light source for generating fundamental light that is then converted/mixed by a frequency conversion module to generate UV-DUV laser light. The fundamental light source includes a nonlinear chirp element (e.g., a Bragg grating or an electro-optic modulator) that adds a nonlinear chirp to the seed light laser system prior to amplification by the fiber amplifier(s) (e.g., doped fiber or Raman amplifiers). The nonlinear chirp includes an x2 or higher nonlinearity and is configured to compensates for the Self Phase Modulation (SPM) characteristics of the fiber-based amplifiers such that fundamental light is generated that has a spectral E95 bandwidth within five times that of the seed light. When multiple series-connected amplifiers are used, either a single nonlinear chirp element is provided before the amplifier string, or a chirp elements are included before each amplifier.

Abstract: A laser system for semiconductor inspection includes a fiber-based fundamental light source for generating fundamental light that is then converted/mixed by a frequency conversion module to generate UV-DUV laser light. The fundamental light source includes a nonlinear chirp element (e.g., a Bragg grating or an electro-optic modulator) that adds a nonlinear chirp to the seed light laser system prior to amplification by the fiber amplifier(s) (e.g., doped fiber or Raman amplifiers). The nonlinear chirp includes an x2 or higher nonlinearity and is configured to compensate for the Self Phase Modulation (SPM) characteristics of the fiber-based amplifiers such that fundamental light is generated that has a spectral E95 bandwidth within five times that of the seed light. When multiple series-connected amplifiers are used, either a single nonlinear chirp element is provided before the amplifier string, or chirp elements are included before each amplifier.

Abstract: An optical system for detecting contaminants and defects on a test surface includes an improved laser system for generating a laser beam and optics directing the laser beam along a path onto the test surface, and producing an illuminated spot thereon. A detector and ellipsoidal mirrored surface are also provided with an axis of symmetry about a line perpendicular to the test surface. In one embodiment, an optical system for detecting anomalies of a sample includes the improved laser system for generating first and second beams, first optics for directing the first beam of radiation onto a first spot on the sample, second optics for directing the second beam onto a second spot on the sample, with the first and second paths at different angles of incidence to the sample surface. In another embodiment, a surface inspection apparatus includes an illumination system configured to focus beams at non-normal incidence angles.

Abstract: A laser for generating an output wavelength of approximately 193.4 nm includes a fundamental laser, an optical parametric generator, a fourth harmonic generator, and a frequency mixing module. The optical parametric generator, which is coupled to the fundamental laser, can generate a down-converted signal. The fourth harmonic generator, which may be coupled to the optical parametric generator or the fundamental laser, can generate a fourth harmonic. The frequency mixing module, which is coupled to the optical parametric generator and the fourth harmonic generator, can generate a laser output at a frequency equal to a sum of the fourth harmonic and twice a frequency of the down-converted signal.

Abstract: An inspection system including a catadioptric objective that facilitates dark-field inspection is provided. The objective includes an outer element furthest from the specimen having an outer element partial reflective surface oriented toward the specimen, an inner element nearest the specimen having a center lens comprising an inner element partial reflective surface oriented away from the specimen, and a central element positioned between the outer lens and the inner lens. At least one of the outer element, inner element, and central element has an aspheric surface. The inner element is spatially configured to facilitate dark-field inspection of the specimen.

Abstract: A mode-locked laser system operable at low temperature can include an annealed, frequency-conversion crystal and a housing to maintain an annealed condition of the crystal during standard operation at the low temperature. In one embodiment, the crystal can have an increased length. First beam shaping optics can be configured to focus a beam from a light source to an elliptical cross section at a beam waist located in or proximate to the crystal. A harmonic separation block can divide an output from the crystal into beams of different frequencies separated in space. In one embodiment, the mode-locked laser system can further include second beam shaping optics configured to convert an elliptical cross section of the desired frequency beam into a beam with a desired aspect ratio, such as a circular cross section.

Abstract: The present invention includes a fundamental laser light source configured to generate fundamental wavelength laser light, an optical crystal configured to receive fundamental laser light from the fundamental laser light source, the optical crystal configured to generate alternate wavelength light by frequency converting a portion of the received fundamental laser light to alternate wavelength light, an auxiliary light source configured to generate auxiliary wavelength light, the auxiliary wavelength light having a wavelength different from the fundamental wavelength laser light and the alternate wavelength light, the fundamental laser light source and the auxiliary light source oriented such that the fundamental laser light copropagates with the auxiliary light through a surface of the optical crystal, and a detector configured to detect at least one of fundamental wavelength laser light scattered by the optical crystal, alternate wavelength light scattered by the optical crystal, or auxiliary light scattere

Abstract: An improved solid-state laser for generating sub-200 nm light is described. This laser uses a fundamental wavelength between about 1030 nm and 1065 nm to generate the sub-200 nm light. The final frequency conversion stage of the laser creates the sub-200 nm light by mixing a wavelength of approximately 1109 nm with a wavelength of approximately 234 nm. By proper selection of non-linear media, such mixing can be achieved by nearly non-critical phase matching. This mixing results in high conversion efficiency, good stability, and high reliability.

Abstract: A laser for generating an output wavelength of approximately 193.4 nm includes a fundamental laser, an optical parametric generator, a fourth harmonic generator, and a frequency mixing module. The optical parametric generator, which is coupled to the fundamental laser, can generate a down-converted signal. The fourth harmonic generator, which may be coupled to the optical parametric generator or the fundamental laser, can generate a fourth harmonic. The frequency mixing module, which is coupled to the optical parametric generator and the fourth harmonic generator, can generate a laser output at a frequency equal to a sum of the fourth harmonic and twice a frequency of the down-converted signal.

Abstract: A pulse multiplier includes a beam splitter and one or more mirrors. The beam splitter receives a series of input laser pulses and directs part of the energy of each pulse into a ring cavity. After circulating around the ring cavity, part of the pulse energy leaves the ring cavity through the beam splitter and part of the energy is recirculated. By selecting the ring cavity optical path length, the repetition rate of an output series of laser pulses can be made to be a multiple of the input repetition rate. The relative energies of the output pulses can be controlled by choosing the transmission and reflection coefficients of the beam splitter. This pulse multiplier can inexpensively reduce the peak power per pulse while increasing the number of pulses per second with minimal total power loss.

Abstract: The present invention includes a fundamental laser light source configured to generate fundamental wavelength laser light, a first nonlinear optical crystal configured to generate first alternate wavelength light; a second nonlinear optical crystal configured to generate second alternate wavelength light; a dual wavelength Brewster angle waveplate configured to rotate a polarization of the first alternate wavelength light relative to the second alternate wavelength light such that the first and second alternate wavelength light have the same polarization; a set of Brewster angle wavefront processing optics configured to condition the first and second alternate wavelengths of light; a harmonic separator configured to separate the first alternate wavelength light from the second alternate wavelength light; and a Brewster angle output window configured to transmit the first or second alternate wavelengths of light from the interior of a laser frequency conversion system to the exterior of the laser frequency con

Abstract: The present invention is directed to a laser system in which a current laser wavefront performance of the laser system may be monitored. Further, the laser system embodiments disclosed herein may be configured for correcting the laser wavefront internally via correction system(s) within the laser system. Still further, the correction system(s) disclosed herein may provide a long lifetime of performance and may be configured for having a minimal impact on photocontamination.

Abstract: A system and method for inspection is disclosed. The design includes an objective employed for use with light energy having a wavelength in various ranges, including approximately 266 to 1000 nm, 157 nm through infrared, and other ranges. The objective includes a focusing lens group having at least one focusing lens configured to receive light, a field lens oriented to receive focused light energy from said focusing lens group and provide intermediate light energy, and a Mangin mirror arrangement positioned to receive the intermediate light energy from the field lens and form controlled light energy. Each focusing lens has a reduced diameter, such as a diameter of less than approximately 100 mm, and a maximum corrected field size of approximately 0.15 mm. An immersion substance, such as oil, water, or silicone gel, may be employed prior to passing controlled light energy to the specimen inspected.

Abstract: An exemplary illumination source for an inspection system includes a pulsed seed laser having a wavelength of approximately 1104 nm and a continuous wave, Raman seed laser having a wavelength of approximately 1160 nm. An optical coupler can combine outputs of the pulsed seed laser and the continuous wave, Raman seed laser. Pre-amplification stages can receive an output of the optical coupler. A power amplifier can receive an output of the pre-amplification stages. A sixth harmonic can be generated using the amplified, combined wavelength. Systems for inspecting a specimen such as a reticle, photomask or wafer can include one of the illumination sources described herein.

Abstract: A catadioptric objective configured to inspect a specimen is provided. The catadioptric objective includes a Mangin element having one surface at a first axial location and an extension element positioned together with the Mangin element. The extension element provides a second surface at a second axial location. Certain light energy reflected from the specimen passes to the second surface of the extension element, the Mangin element, and through a plurality of lenses. An aspheric surface may be provided, and light energy may be provided to the specimen using diverting elements such as prisms or reflective surfaces.

Abstract: A laser system for semiconductor inspection includes a fiber-based fundamental light source for generating fundamental light that is then converted/mixed by a frequency conversion module to generate UV-DUV laser light. The fundamental light source includes a nonlinear chirp element (e.g., a Bragg grating or an electro-optic modulator) that adds a nonlinear chirp to the seed light laser system prior to amplification by the fiber amplifier(s) (e.g., doped fiber or Raman amplifiers). The nonlinear chirp includes an x2 or higher nonlinearity and is configured to compensate for the Self Phase Modulation (SPM) characteristics of the fiber-based amplifiers such that fundamental light is generated that has a spectral E95 bandwidth within five times that of the seed light. When multiple series-connected amplifiers are used, either a single nonlinear chirp element is provided before the amplifier string, or chirp elements are included before each amplifier.

Abstract: Improved laser systems and associated techniques generate an ultra-violet (UV) wavelength of approximately 193.368 nm from a fundamental vacuum wavelength near 1064 nm. Preferred embodiments separate out an unconsumed portion of an input wavelength to at least one stage and redirect that unconsumed portion for use in another stage. The improved laser systems and associated techniques result in less expensive, longer life lasers than those currently being used in the industry. These laser systems can be constructed with readily-available, relatively inexpensive components.

Abstract: An improved solid-state laser for generating 193 nm light is described. This laser uses the 6th harmonic of a fundamental wavelength near 1160 nm to generate the 193 nm light. The laser mixes the 1160 nm fundamental wavelength with the 5th harmonic, which is at a wavelength of approximately 232 nm. By proper selection of non-linear media, such mixing can be achieved by nearly non-critical phase matching. This mixing results in high conversion efficiency, good stability, and high reliability.