Abstract: A DUV laser includes an optical bandwidth filtering device, such as etalon, which is disposed outside of the laser oscillator cavity of the fundamental laser, and which directs one range of wavelengths into one portion of a frequency conversion chain and another range of wavelengths into another portion of the frequency conversion train, thereby reducing the bandwidth of the DUV laser output while maintaining high conversion efficiency in the frequency conversion chain.

Abstract: An optical inspection system that utilizes sub-200 nm incident light beam to inspect a surface of an object for defects is described. The sub-200 nm incident light beam is generated by combining first light having a wavelength of about 1109 nm with second light having a wavelength of approximately 234 nm. An optical system includes optical components configured to direct the incident light beam to a surface of the object, and image relay optics are configured to collect and relay at least two channels of light to a sensor, where at least one channel includes light reflected from the object, and at least one channel includes light transmitted through the object. The sensor is configured to simultaneously detect both the reflected and transmitted light. A laser for generating the sub-200 nm incident light beam includes a fundamental laser, two or more harmonic generators, a frequency doubler and a two frequency mixing stages.

Abstract: Optimization of optical parametric models for structural analysis using optical critical dimension metrology is described. A method includes determining a first optical model fit for a parameter of a structure. The first optical model fit is based on a domain of quantities for a first model of the structure. A first near optical field response is determined for a first quantity of the domain of quantities and a second near optical field response is determined for a second, different quantity of the domain of quantities. The first and second near optical field responses are compared to locate a common region of high optical field intensity for the parameter of the structure. The first model of the structure is modified to provide a second, different model of the structure. A second, different optical model fit is determined for the parameter of the structure based on the second model of the structure.

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 pulse multiplier includes a polarizing beam splitter, a wave plate, and a set of multi-surface reflecting components (e.g., one or more etalons and one or more mirrors). The polarizing beam splitter passes input laser pulses through the wave plate to the multi-surface reflecting components, which reflect portions of each input laser pulse back through the wave plate to the polarizing beam splitter. The polarizing beam splitter reflects each reflected portion to form an output of the pulse multiplier. The multi-surface reflecting components are configured such that the output pulses exiting the pulse multiplier have an output repetition pulse frequency rate that is at least double the input repetition pulse frequency.

Abstract: A pulse multiplier includes a polarizing beam splitter, a wave plate, and a set of multi-surface reflecting components (e.g., one or more etalons and one or more mirrors). The polarizing beam splitter passes input laser pulses through the wave plate to the multi-surface reflecting components, which reflect portions of each input laser pulse back through the wave plate to the polarizing beam splitter. The polarizing beam splitter reflects each reflected portion to form an output of the pulse multiplier. The multi-surface reflecting components are configured such that the output pulses exiting the pulse multiplier have an output repetition pulse frequency rate that is at least double the input repetition pulse frequency.

Abstract: A deep ultra-violet (DUV) continuous wave (CW) laser includes a fundamental CW laser configured to generate a fundamental frequency with a corresponding wavelength between about 1 ?m and 1.1 ?m, a third harmonic generator module including one or more non-linear optical (NLO) crystals that generate a third harmonic and an optional second harmonic, and a fifth harmonic generator. The fifth harmonic generator module includes a cavity resonant at the fundamental frequency, and combines the fundamental frequency with the third harmonic in a first NLO crystal to generate a fourth harmonic, then combines the fourth harmonic with unconsumed fundamental frequency in a second NLO crystal to generate the fifth harmonic. One or more lenses are used to focus the third and fourth harmonics in the first and second NLO crystals, respectively.

Abstract: An optical inspection system that utilizes sub-200 nm incident light beam to inspect a surface of an object for defects is described. The sub-200 nm incident light beam is generated by combining first light having a wavelength of about 1109 nm with second light having a wavelength of approximately 234 nm. An optical system includes optical components configured to direct the incident light beam to a surface of the object, and image relay optics are configured to collect and relay at least two channels of light to a sensor, where at least one channel includes light reflected from the object, and at least one channel includes light transmitted through the object. The sensor is configured to simultaneously detect both the reflected and transmitted light. A laser for generating the sub-200 nm incident light beam includes a fundamental laser, two or more harmonic generators, a frequency doubler and a two frequency mixing stages.

Abstract: A pulse multiplier includes a polarizing beam splitter, a wave plate, and a set of multi-surface reflecting components (e.g., one or more etalons and one or more mirrors). The polarizing beam splitter passes input laser pulses through the wave plate to the multi-surface reflecting components, which reflect portions of each input laser pulse back through the wave plate to the polarizing beam splitter. The polarizing beam splitter reflects each reflected portion to form an output of the pulse multiplier. The multi-surface reflecting components are configured such that the output pulses exiting the pulse multiplier have an output repetition pulse frequency rate that is at least double the input repetition pulse frequency.

Abstract: A multi-column electron beam device includes an electron source comprising multiple field emitters fabricated on a surface of a silicon substrate. To prevent oxidation of the silicon, a thin, contiguous boron layer is disposed directly on the output surface of the field emitters. The field emitters can take various shapes including a pyramid, a cone, or a rounded whisker. Optional gate layers may be placed on the output surface near the field emitters. The field emitter may be p-type or n-type doped. Circuits may be incorporated into the wafer to control the emission current. A light source may be configured to illuminate the electron source and control the emission current. The multi-column electron beam device may be a multi-column electron beam lithography system configured to write a pattern on a sample.

Abstract: A multi-column electron beam device includes an electron source comprising multiple field emitters fabricated on a surface of a silicon substrate. To prevent oxidation of the silicon, a thin, contiguous boron layer is disposed directly on the output surface of the field emitters. The field emitters can take various shapes including a pyramid, a cone, or a rounded whisker. Optional gate layers may be placed on the output surface near the field emitters. The field emitter may be p-type or n-type doped. Circuits may be incorporated into the wafer to control the emission current. A light source may be configured to illuminate the electron source and control the emission current. The multi-column electron beam device may be a multi-column electron beam lithography system configured to write a pattern on a sample.

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 DUV laser includes an optical bandwidth filtering device, such as etalon, which is disposed outside of the laser oscillator cavity of the fundamental laser, and which directs one range of wavelengths into one portion of a frequency conversion chain and another range of wavelengths into another portion of the frequency conversion train, thereby reducing the bandwidth of the DUV laser output while maintaining high conversion efficiency in the frequency conversion chain.

Abstract: A DUV laser includes an optical bandwidth filtering device, such as etalon, which is disposed outside of the laser oscillator cavity of the fundamental laser, and which directs one range of wavelengths into one portion of a frequency conversion chain and another range of wavelengths into another portion of the frequency conversion train, thereby reducing the bandwidth of the DUV laser output while maintaining high conversion efficiency in the frequency conversion chain.

Abstract: A pulse multiplier includes a polarizing beam splitter, a wave plate, and a set of mirrors. The polarizing beam splitter receives an input laser pulse. The wave plate receives light from the polarized beam splitter and generates a first set of pulses and a second set of pulses. The first set of pulses has a different polarization than the second set of pulses. The polarizing beam splitter, the wave plate, and the set of mirrors create a ring cavity. The polarizing beam splitter transmits the first set of pulses as an output of the pulse multiplier and reflects the second set of pulses into the ring cavity. 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: A laser for generating deep ultra-violet (DUV) continuous wave (CW) light includes a second-harmonic generator and a fourth-harmonic generator. The fourth-harmonic generator includes a plurality of mirrors as well as a first non-linear optical (NLO) crystal and a pair of tilted plates. The first NLO crystal generates the light having the fourth harmonic wavelength and a first astigmatism, and is placed in operative relation to the plurality of mirrors. The pair of tilted plates is placed in operative relation to the first NLO crystal such that the light having the second harmonic wavelength passes through both of the tilted plates. Notably, the pair of tilted plates are disposed at substantially equal and opposite angles about respective parallel axes such that they introduce a second astigmatism that corrects for the first astigmatism while minimizing displacement of the circulated light.

Abstract: An improved laser uses a pump laser with a wavelength near 1109 nm and a fundamental wavelength near 1171 nm to generate light at a wavelength between approximately 189 nm and approximately 200 nm, e.g. 193 nm. The laser mixes the 1109 nm pump wavelength with the 5th harmonic of the 1171 nm fundamental, which is at a wavelength of approximately 234.2 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 deep ultra-violet (DUV) continuous wave (CW) laser includes a fundamental CW laser configured to generate a fundamental frequency with a corresponding wavelength between about 1 ?m and 1.1 ?m, a third harmonic generator module including one or more non-linear optical (NLO) crystals that generate a third harmonic and an optional second harmonic, and a fifth harmonic generator. The fifth harmonic generator module includes a cavity resonant at the fundamental frequency, and combines the fundamental frequency with the third harmonic in a first NLO crystal to generate a fourth harmonic, then combines the fourth harmonic with unconsumed fundamental frequency in a second NLO crystal to generate the fifth harmonic. One or more lenses are used to focus the third and fourth harmonics in the first and second NLO crystals, respectively.

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 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.