Abstract: A narrow band molecular fluorine laser system includes an oscillator and an amplifier, wherein the oscillator produces a 157 nm beam having a linewidth less than 1 pm and the amplifier increases the power of the beam above a predetermined amount, such as more than one or several Watts. The oscillator includes a discharge chamber filled with a laser gas including molecular fluorine and a buffer gas, electrodes within the discharge chamber connected to a discharge circuit for energizing the molecular fluorine, and a resonator including the discharge chamber for generating a laser beam having a wavelength around 157 nm. Line-narrowing optics are included intra- and/or extra-resonator for reducing the linewidth of the laser beam to less than 1 pm. The amplifier may be the same or a different discharge chamber, and optical and/or electronic delays may be used for timing pulses from the oscillator to reach the amplifier at a maximum in the discharge current of the amplifier.

Abstract: A molecular fluorine laser system includes a discharge chamber filled with a gas mixture at least including molecular fluorine and a buffer gas, multiple electrodes within the discharge chamber and connected to a discharge circuit for energizing the gas mixture, and a resonator for generating an output beam. The resonator includes at least one wavelength selection optic for selecting a primary line among multiple characteristic photoemission lines around 157 nm including suppressing a secondary line among the plurality of characteristic photoemission lines around 157 nm to below 1%. The resonator further includes at least one polarizing optic for polarizing the selected line so that the output beam has a polarization of at least substantially 95%, and preferably 97.5% or more.

Abstract: A molecular fluorine (F2) laser is provided wherein the gas mixture comprises molecular fluorine for generating a spectral emission including two or three closely spaced lines around 157 nm. An etalon provides line selection such that the output beam only includes one of these lines. The etalon may also serve to outcouple the beam and/or narrow the selected line. Alternatively, a prism provides the line selection and the etalon narrows the selected line. The etalon may be a resonator reflector which also selects a line, while another element outcouples the beam. The etalon plates comprise a material that is substantially transparent at 157 nm, such as CaF2, MgF2, LiF2, BaF2, LiF, SrF2, quartz and fluorine doped quartz. The etalon plates are separated by spacers comprising a material having a low thermal expansion constant, such as invar, zerodur®, ultra low expansion glass, and quartz.

Abstract: A narrow band molecular fluorine laser system includes an oscillator and an amplifier, wherein the oscillator produces a 157 nm beam having a linewidth less than 1 pm and the amplifier increases the power of the beam above a predetermined amount, such as more than one or several Watts. The oscillator includes a discharge chamber filled with a laser gas including molecular fluorine and a buffer gas, electrodes within the discharge chamber connected to a discharge circuit for energizing the molecular fluorine, and a resonator including the discharge chamber for generating a laser beam having a wavelength around 157 nm. Line-narrowing optics are included intra- and/or extra-resonator for reducing the linewidth of the laser beam to less than 1 pm. The amplifier may be the same or a different discharge chamber, and optical and/or electronic delays may be used for timing pulses from the oscillator to reach the amplifier at a maximum in the discharge current of the amplifier.

Abstract: A tunable laser is provided having a gain medium and a resonator for generating a laser beam, and an angular dispersion element. The laser further includes a beam expander with adjustable magnification for adjusting an angular dispersion provided by the dispersion element. The adjustable beam expander preferably includes one or two rotatable prisms. When two prisms are used, the prisms are preferably synchronously rotatable according to a preset ratio such that any changes in refraction angle due to the rotation of the first prism are automatically compensated by the rotation of the second prism. A single prism may serve both as a dispersion element and as a beam expansion element. A processor preferably monitors the linewidth and wavelength of the output beam and adjusts an orientation of the prism or prisms of the expansion unit, and the tilt of either a reflection grating or a highly reflective mirror of the resonator in a feedback loop.

Abstract: A molecular fluorine (F2) laser is provided wherein the gas mixture includes molecular fluorine for generating an emission spectrum including two or three closely spaced lines around 157 nm. An optical method and means are provided for selecting an emission line from among the plurality of closely spaced emission lines of the molecular fluorine laser gas volume and broadening the spectrum of said selected emission line. This approach of broadening the spectrum reduces the coherence length of the output beam. As a result, speckle may be reduced or avoided in microlithography applications.

Abstract: A narrow band molecular fluorine laser system includes an oscillator and an amplifier, wherein the oscillator produces a 157 nm beam having a linewidth less than 1 pm and the amplifier increases the power of the beam above a predetermined amount, such as more than one or several Watts. The oscillator includes a discharge chamber filled with a laser gas including molecular fluorine and a buffer gas, electrodes within the discharge chamber connected to a discharge circuit for energizing the molecular fluorine, and a resonator including the discharge chamber for generating a laser beam having a wavelength around 157 nm. Line-narrowing optics are included intra- and/or extra-resonator for reducing the linewidth of the laser beam to less than 1 pm. The amplifier may be the same or a different discharge chamber, and optical and/or electronic delays may be used for timing pulses from the oscillator to reach the amplifier at a maximum in the discharge current of the amplifier.

Abstract: A system is provided for delivering a laser beam of wavelength less than 200 nm from a laser, such as an F2 laser or ArF laser, through a sealed enclosure sealably connected to the laser, and preferably to another housing, leading ultimately to a workpiece. The enclosure is preferably evacuated and back-filled with an inert gas to adequately deplete any air, water, hydrocarbons or oxygen within the enclosure. Thereafter or alternatively, an inert gas flow is established and maintained within the enclosure during operation of the laser. The inert gas preferably has high purity, e.g., more than 99.5% and preferably more than 99.999%, wherein the inert is preferably nitrogen or a noble gas. The enclosure is preferably sealed by a window transparent to the sub-200 nm radiation for preventing contaminants generated in the enclosure from entering the housing and contaminating surfaces therein. The enclosure is preferably made of steel and/or copper, and the window is preferably made of CaF2.

Abstract: A system is provided for delivering a laser beam of wavelength less than 200 nm from a laser, such as an F2 laser or ArF laser, through a sealed enclosure sealably connected to the laser, and preferably to another housing, leading ultimately to a workpiece. The enclosure is preferably evacuated and back-filled with an inert gas to adequately deplete any air, water, hydrocarbons or oxygen within the enclosure. Thereafter or alternatively, an inert gas flow is established and maintained within the enclosure during operation of the laser. The inert gas preferably has high purity, e.g., more than 99.5% and preferably more than 99.999%, wherein the inert is preferably nitrogen or a noble gas. The enclosure is preferably sealed by a window transparent to the sub-200 nm radiation for preventing contaminants generated in the enclosure from entering the housing and contaminating surfaces therein. The enclosure is preferably made of steel and/or copper, and the window is preferably made of CaF2.

Abstract: A beam delivery system for a laser emitting at a relevant wavelength of less than 200 nm is provided. The system includes a sealed enclosure connected to the laser and surrounding the path of the beam as it exits the laser resonator. The enclosure extends between the laser output coupler and a photodetector sensitive at the wavelength of the relevant laser emission. The interior of the enclosure, and thus the beam path between the output coupler and the detector, is substantially free of species that strongly photoabsorb radiation at the relevant laser emission wavelength. A beam splitting element diverts at least a portion of the beam for measurement by the detector. The beam splitting element preferably includes a beam splitting mirror, holographic beam sampler or diffraction grating. In addition, optics are preferably provided for filtering a visible portion of the diverted beam, so that substantially only a VUV portion of the diverted beam is received at the detector.

Abstract: A side-pumped, diode-pumped solid state laser device includes an elongated housing having an elongated cavity defined therein and further having an elongated opening defined between the cavity and the exterior of the housing. A solid state rod is disposed within the cavity and is preferably surrounded by a cooling fluid. A cover seal sealably covering the opening and thereby encloses the cavity. The cover seal is formed of a material that is at least substantially transparent to pumping radiation at a predetermined pumping wavelength. A diode array emits the pumping radiation that traverses the cover seal and the opening to be absorbed by the rod to excite laser active species within the rod. The laser device further includes a resonator including the rod disposed therein for generating a laser beam.

Abstract: A beam delivery system for a laser emitting at a relevant wavelength of less than 200 nm is provided. The system includes a sealed enclosure connected to the laser and surrounding the path of the beam as it exits the laser resonator. The enclosure extends between the laser output coupler and a photodetector sensitive at the wavelength of the relevant laser emission. The interior of the enclosure, and thus the beam path between the output coupler and the detector, is substantially free of species that strongly photoabsorb radiation at the relevant laser emission wavelength. A beam splitting element diverts at least a portion of the beam for measurement by the detector. The beam splitting element preferably includes a beam splitting mirror, holographic beam sampler or diffraction grating. In addition, optics are preferably provided for filtering a visible portion of the diverted beam, so that substantially only a VUV portion of the diverted beam is received at the detector.

Abstract: A system is provided for delivering a laser beam of wavelength less than 200 nm from a laser, such as an F2 laser or ArF laser, through a sealed enclosure sealably connected to the laser, and preferably to another housing, leading ultimately to a workpiece. The enclosure is preferably evacuated and back-filled with an inert gas to adequately deplete any air, water, hydrocarbons or oxygen within the enclosure. Thereafter or alternatively, an inert gas flow is established and maintained within the enclosure during operation of the laser. The inert gas preferably has high purity, e.g., more than 99.5% and preferably more than 99.999%, wherein the inert is preferably nitrogen or a noble gas. The enclosure is preferably sealed by a window transparent to the sub-200 nm radiation for preventing contaminants generated in the enclosure from entering the housing and contaminating surfaces therein. The enclosure is preferably made of steel and/or copper, and the window is preferably made of CaF2.

Abstract: A method and apparatus are provided for delivering a laser beam from a laser, such as an F2 laser, to a target through a sealed enclosure. The enclosure is evacuated and back-filled with an inert gas repeatedly for a number of times sufficient to adequately deplete any air, water, hydrocarbons or oxygen within the enclosure. Thereafter, an inert gas flow is established and maintained within the enclosure during operation of the laser. Propagation with significant transmittance of a sub-200 nm beam through the enclosure is particularly enabled.

Abstract: This invention concerns a process useful for increasing the accuracy of the shape of a laser ablated feature formed on a substrate, especially where the substrate is a polymeric article. The process includes irradiating the polymeric article with laser light that has passed through a retardation plate selected from stationary adjustable plates, rotating plates or spinning plates, preferable in multiples of quarter-waves or half-waves. This invention also concerns a laser apparatus useful for making ablated features in a substrate having a radiation source; a mask positioned between the radiation source and a substrate to be irradiated, and a retardation plate which is stationary and adjustable, rotating or spinning plates.

Abstract: A molecular fluorine (F.sub.2) laser is provided wherein the gas mixture comprises molecular fluorine for generating a spectral emission including two or three closely spaced lines around 157 nm. An etalon provides line selection such that the output beam only includes one of these lines. The etalon may also serve to outcouple the beam and/or narrow the selected line. Alternatively, a prism provides the line selection and the etalon narrows the selected line. The etalon may be a resonator reflector which also selects a line, while another element outcouples the beam. The etalon plates, preferably uncoated, comprise a material that is transparent at 157 nm, such as CaF.sub.2, MgF.sub.2, LiF.sub.2, BaF.sub.2, SrF.sub.2, quartz and fluorine doped quartz. The etalon plates are separated by spacers comprising a material having a low thermal expansion constant, such as invar, zerodur.RTM., ultra low expansion glass, and quartz. A gas such as helium or a solid such as CaF.sub.

Abstract: A laser system, and method of operating the same, that includes a resonant cavity that terminates at one end with a mirror and at the other end with a dispersive wavelength selector, a gain medium disposed in the resonant cavity, and a power supply that excites the gain medium to generate a laser beam that oscillates along an optical axis of the resonant cavity. The dispersive wavelength selector disperses the laser beam at different angles in a critical plane as a function of wavelength so that only a particular range of wavelengths in the beam are aligned to the optical axis and oscillate in the resonant cavity. The critical plane is parallel to the laser beam. The resonant cavity further includes a wavefront curvature compensating lens that is selectively rotatable about an axis of rotation that is perpendicular to the critical plane.

Abstract: A laser device which is tunable within the mid-IR range is provided. The device includes a thin etalon, formed as an uncoated plane-parallel plate of high refractive index material, which is transparent for both pump and resonant (signal, idler or both) radiation, for coupling the pump beam to the cavity of an optical parametric oscillator. Such an optical element does not require thin film optical coatings and inherently possesses a high optical damage threshold. Furthermore, high reflectivity at the pump wavelength and high transmittance for oscillating radiations are provided, by orienting the etalon at the Brewster angle. Examples of such materials include silicon and germanium, which are transparent at wavelengths longer than approximately 1 .mu.m and 2 .mu.m, respectively, and have refractive indices of n=3.4 and n=4.0, respectively.

Abstract: A solid state laser is provided including a rare earth-doped YAG, YLF, YVO, GSGG, YALO or GdVO oscillator crystal, at least one laser diode pumping source, a Q-switch short pulse generator, a frequency doubling stage and frequency quadrupling or quintupling stages. The frequency quadrupling or quintupling stages include a nonlinear optical crystal such as CLBO, BBO or LBO built into a housing. The housing is sealed off to prevent external moisture and other atmospheric impurities from accessing the crystal at its interior. The housing interior is configured for purging with one or more external inert gases or dry air through valve controls. The housing is equipped with a mechanism for controlling the temperature of the interior of the housing, and consequently for controlling the temperature of the crystal. The temperature controlling mechanism enables heating and cooling of the crystal, as well as maintaining the crystal at a constant selected temperature.

Abstract: A laser system having a resonant cavity that is stable in one axis so that a wavelength selector can be used for producing a narrow line output, and is unstable in an orthogonal axis for high energy extraction efficiency and for low output beam divergence. The resonant cavity terminates at one end with a cylindrical mirror and at the other end with a dispersive wavelength selector. A gain medium is disposed in the resonant cavity, and is excited by a power supply to generate a laser beam that oscillates in the resonant cavity. A portion of the laser beam is coupled out of the resonant cavity as an output laser beam. The cylindrical mirror has a cylindrical reflecting surface oriented to diverge the laser beam at a first azimuthal angle relative to an axis of the resonant cavity. The dispersive wavelength selector disperses the laser beam as a function of wavelength at a second azimuthal angle relative to the resonant cavity axis. The second azimuthal angle is orthogonal to the first azimuthal angle.