37 results about "Line narrowing" patented technology

An integrated circuit lithography technique called spectral engineering by Applicants, for bandwidth control of an electric discharge laser. In a preferred process, a computer model is used to model lithographic parameters to determine a desired laser spectrum needed to produce a desired lithographic result. A fast responding tuning mechanism is then used to adjust center wavelength of laser pulses in a burst of pulses to achieve an integrated spectrum for the burst of pulses approximating the desired laser spectrum. The laser beam bandwidth is controlled to produce an effective beam spectrum having at least two spectral peaks in order to produce improved pattern resolution in photo resist film. Line narrowing equipment is provided having at least one piezoelectric drive and a fast bandwidth detection control system having a time response of less than about 2.0 millisecond. In a preferred embodiment, a wavelength tuning mirror is dithered at dither rates of more than 500 dithers per second in phase with the repetition rate of the laser. In one case, the piezoelectric drive was driven with a square wave signal and in a second case it was driven with a sine wave signal. In another embodiment, the maximum displacement was matched on a one-to-one basis with the laser pulses in order to produce a desired average spectrum with two peaks for a series of laser pulses. Other preferred embodiments utilize three separate wavelength tuning positions producing a spectrum with three separate peaks.

An injection seeded modular gas discharge laser system capable of producing high quality pulsed laser beams at pulse rates of about 4,000 Hz or greater and at pulse energies of about 5 mJ or greater. Two separate discharge chambers are provided, one of which is a part of a master oscillator producing a very narrow band seed beam which is amplified in the second discharge chamber. The chambers can be controlled separately permitting separate optimization of wavelength parameters in the master oscillator and optimization of pulse energy parameters in the amplifying chamber. A preferred embodiment in an ArF excimer laser system configured as a MOPA and specifically designed for use as a light source for integrated circuit lithography. In the preferred MOPA embodiment, each chamber comprises a single tangential fan providing sufficient gas flow to permit operation at pulse rates of 4000 Hz or greater by clearing debris from the discharge region in less time than the approximately 0.25 milliseconds between pulses. The master oscillator is equipped with a line narrowing package having a very fast tuning mirror capable of controlling centerline wavelength on a pulse-to-pulse basis at repetition rates of 4000 Hz or greater to a precision of less than 0.2 pm.

A line narrowing method and module for a narrow band DUV high power high repetition rate gas discharge laser producing output laser light pulse beam pulses in bursts of pulses, the module having a nominal optical path are disclosed which may comprise: a dispersive center wavelength selection optic moveably mounted within an optical path of the line narrowing module, selecting at least one center wavelength for each pulse determined at least in part by the angle of incidence of the laser light pulse beam containing the respective pulse on the dispersive wavelength selection optic; a first tuning mechanism operative in part to select the angle of incidence of the laser light pulse beam containing the respective pulse upon the dispersive center wavelength selection optic, by selecting an angle of transmission of the laser light pulse beam containing the pulse toward the dispersive center wavelength selection optic; a second tuning mechanism operative in part to select the angle of incidence of the laser light pulse beam containing the respective pulse by changing the position of the dispersive center wavelength selection optic relative to the nominal optical path of the line narrowing module; wherein the second tuning mechanism coarsely selects a value for the center wavelength and the first tuning mechanism more finely selects the value for the center wavelength. The apparatus and method may further comprise at least one beam expanding and redirecting prism in the optical path of the line narrowing module; the first tuning mechanism selecting an angle of incidence of the at least a first spatially defined portion of the laser light pulse beam by changing the position of the at least one beam expanding prism relative to the nominal optical path of the line narrowing module. The first and second tuning mechanisms may be controlled by a center wavelength controller during a burst based upon feedback from a center wavelength detector detecting the center wavelength of at least one other pulse in the burst of pulses and the controller providing the feedback based upon an algorithm employing the detected center wavelength for the at least one other pulse in the burst. The first tuning mechanism may comprise an electro-mechanical course positioning mechanism and a fine positioning mechanism comprising an actuatable material that changes position or shape when actuated.

A line-narrowed excimer or 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 connected to a discharge circuit for energizing the gas mixture, a resonator including a pair of resonator reflecting surfaces disposed on either side of the discharge chamber for generating a laser beam, and a line-narrowing / selection unit within the resonator for narrowing the bandwidth of the laser beam. The resonator further includes a third reflecting surface which is deformable and disposed between the pair of resonator reflecting surfaces. The line-narrowing / selection unit preferably includes a beam expander and a dispersive element, wherein the deformable third reflecting surface is disposed between the beam expander and the dispersive element.

In a line-narrowed gas laser system such as a line-narrowed molecular fluorine laser system, ASE is cut off to obtain a spectral linewidth of 0.2 pm or lower and a spectral purity of 0.5 pm or lower. The laser system comprises a laser chamber filled with an F2-containing laser gas, discharge electrodes located in the laser chamber, a laser resonator and a line-narrowing module located in the laser resonator with a wavelength selection element, so that a line-narrowed laser beam emerges from the laser resonator. To cut off ASE from the laser beam emerging from the laser resonator, the duration from laser emission by discharge to generation of a laser beam is preset. Rise of the sidelight is made so gentle that the starting point of a laser pulse can exist after the time of the first sidelight peak.

A line narrowing method and module for a narrow band DUV high power high repetition rate gas discharge laser producing output laser light pulse beam pulses in bursts of pulses, the module having a nominal optical path are disclosed which may comprise: a dispersive center wavelength selection optic moveably mounted within an optical path of the line narrowing module, selecting at least one center wavelength for each pulse determined at least in part by the angle of incidence of the laser light pulse beam containing the respective pulse on the dispersive wavelength selection optic; a first tuning mechanism operative in part to select the angle of incidence of the laser light pulse beam containing the respective pulse upon the dispersive center wavelength selection optic, by selecting an angle of transmission of the laser light pulse beam containing the pulse toward the dispersive center wavelength selection optic; a second tuning mechanism operative in part to select the angle of incidence of the laser light pulse beam containing the respective pulse by changing the position of the dispersive center wavelength selection optic relative to the nominal optical path of the line narrowing module; wherein the second tuning mechanism coarsely selects a value for the center wavelength and the first tuning mechanism more finely selects the value for the center wavelength. The apparatus and method may further comprise at least one beam expanding and redirecting prism in the optical path of the line narrowing module; the first tuning mechanism selecting an angle of incidence of the at least a first spatially defined portion of the laser light pulse beam by changing the position of the at least one beam expanding prism relative to the nominal optical path of the line narrowing module. The first and second tuning mechanisms may be controlled by a center wavelength controller during a burst based upon feedback from a center wavelength detector detecting the center wavelength of at least one other pulse in the burst of pulses and the controller providing the feedback based upon an algorithm employing the detected center wavelength for the at least one other pulse in the burst. The first tuning mechanism may comprise an electro-mechanical course positioning mechanism and a fine positioning mechanism comprising an actuatable material that changes position or shape when actuated.

An integrated circuit lithography technique called spectral engineering by Applicants, for bandwidth control of an electric discharge laser. In a preferred process, a computer model is used to model lithographic parameters to determine a desired laser spectrum needed to produce a desired lithographic result. A fast responding tuning mechanism is then used to adjust center wavelength of laser pulses in a burst of pulses to achieve an integrated spectrum for the burst of pulses approximating the desired laser spectrum. The laser beam bandwidth is controlled to produce an effective beam spectrum having at least two spectral peaks in order to produce improved pattern resolution in photo resist film. Line narrowing equipment is provided having at least one piezoelectric drive and a fast bandwidth detection control system having a time response of less than about 2.0 millisecond. In a preferred embodiment, a wavelength tuning mirror is dithered at dither rates of more than 500 dithers per second in phase with the repetition rate of the laser. In one case, the piezoelectric drive was driven with a square wave signal and in a second case it was driven with a sine wave signal. In another embodiment, the maximum displacement was matched on a one-to-one basis with the laser pulses in order to produce a desired average spectrum with two peaks for a series of laser pulses. Other preferred embodiments utilize three separate wavelength tuning positions producing a spectrum with three separate peaks.

A method and apparatus is disclosed for operating a laser output light beam pulse line narrowing mechanism that may comprise a nominal center wavelength and bandwidth selection optic; a static wavefront compensation mechanism shaping the curvature of the selection optic; an active wavefront compensation mechanism shaping the curvature of the selection optic and operating independently of the static wavefront compensation mechanism. The method and apparatus may comprise the nominal center wavelength and bandwidth selection optic comprises a grating; the static wavefront compensation mechanism applies a pre-selected bending moment to the grating; the active wavefront compensation mechanism applies a separate selected bending moment to the grating responsive to the control of a bending moment controller based on bandwidth feedback from a bandwidth monitor monitoring the bandwidth of the laser output light beam pulses. The active wavefront compensation mechanism may comprise a pneumatic drive mechanism.

A line-narrowing module for a laser includes a prism beam expander and a grating preferably attached to a heat sink. A pressure-controlled enclosure filled with an inert gas seals the grating and / or other elements of the line-narrowing module. The pressure in the enclosure is adjusted for tuning the wavelength. Preferably, the pressure is controlled by controlling the flow of an inert gas through the enclosure. A pump may be used, or an overpressure flow may be used. Alternatively, a prism of the beam expander or an etalon may be rotatable for tuning the wavelength.

A line narrowing module includes an elliptical mirror having first and second foci and having an opening adjacent to the second focus, a diffraction grating disposed at the first focus so as to separate an incident beam into different lines, and a laser beam dispersion and extraction unit. The laser beam dispersion and extraction unit is situated in the module and composed to disperse a laser beam, incident thereon from a region containing the second focus of the elliptical mirror, over the diffraction grating and selectively extract from the resulting lines a laser beam having a desired narrowed bandwidth. Most of the remainder of the light is reflected by the elliptical mirror to the region having the second focus. A light source that employs the line narrowing module also includes a laser oscillator for generating the beam whose bandwidth is narrowed by the module, and light returning unit that returns one fraction of the beam extracted fron the laser oscillator back to the laser oscillator. Another fraction of the beam is extracted from the laser oscillator through a front window of the laser oscillator, and undergoes line narrowing in the module. The laser beam having the narrowed bandwidth is immediately output as the exposure light from the module, whereas the remainder of the light is returned from the module back to the laser oscillator.

The present invention relates to precision linewidth control and frequency measurements of continuous wave lasers for the near to far IR spectral regions, precision frequency synthesizers and exemplary applications in molecular detection. Methods and systems are disclosed for simultaneous line narrowing of cw lasers, as well as referencing the desired emission wavelength to a frequency comb laser.

An excimer laser and a line-narrowing module capable of increasing and maximizing production yield in semiconductor manufacturing are disclosed. The line-narrowing module utilizes a beam expander that passes laser light, produced by and incident from a generator of the excimer laser and collimates the laser light in one direction. A diffraction grating receives the collimated laser light and diffracts the laser light and causes a traveling direction of the laser light to be separated according to an associated wavelength of the laser light. A multi-wavelength reflector located at a reflecting position on one side between the diffraction grating and the beam expander in order to re-enter the laser light having a multi-wavelength into the generator through the beam expander. The multi-wavelength reflector reflects the laser light consisting of a plurality of wavelengths among the laser light whose traveling direction is separated from the diffraction grating onto the beam expander.

An excimer laser and a line-narrowing module capable of increasing and maximizing production yield in semiconductor manufacturing are disclosed. The line-narrowing module utilizes a beam expander that passes laser light, produced by and incident from a generator of the excimer laser and collimates the laser light in one direction. A diffraction grating receives the collimated laser light and diffracts the laser light and causes a traveling direction of the laser light to be separated according to an associated wavelength of the laser light. A multi-wavelength reflector located at a reflecting position on one side between the diffraction grating and the beam expander in order to re-enter the laser light having a multi-wavelength into the generator through the beam expander. The multi-wavelength reflector reflects the laser light consisting of a plurality of wavelengths among the laser light whose traveling direction is separated from the diffraction grating onto the beam expander.

A molecular fluorine laser includes a discharge chamber filled with a gas mixture including molecular fluorine and a buffer gas and not including a laser active rare gas, multiple electrodes within the discharge chamber defining a discharge region therebetween connected to a pulsed discharge circuit for applying discharge pulses to the electrodes for energizing the gas mixture, and a resonator including the discharge chamber for generating an oscillator laser beam at a wavelength around 157 nm and a bandwidth of less than 0.6 pm. The laser further includes a power amplifier for increasing the energy of the attenuated oscillator laser beam to a second predetermined energy for lithographic processing, a line-narrowing unit for reducing the bandwidth, a low intensity suppressor module to suppress the weaker lines of the F2-laser, and a synchronization unit to synchronize the oscillator and amplifier.

A grating based line narrowing device for line narrowing lasers producing high energy laser beams. A flexure grating mount is provided which virtually eliminates stress on the grating caused by differential thermal expansion between the grating and the housing structure. The grating which is comprised of a very thin aluminum surface on a thick ultra low expansion glass substrate is attached to an aluminum housing structure using a flexure grating mount. At least one flexure joint is provided in the grating mount which permits thermal expansion and contraction of the substrate. In some embodiments the mount comprises a metal plate and the flexure joint is a H-Flex joint (124) with four legs (126) which is machined into the metal plate. In another embodiment two H-Flex joints are provided. In other embodiments, the flexure joint is a dovetail joint permitting one end of the mount to slip relative to the other.

Provided is a laser device that includes a laser chamber in which a pair of discharge electrodes are disposed; a line narrowing optical system including a grating disposed in a position outside the laser chamber; a beam expander optical system that increases a diameter of a light beam, outputted from the laser chamber and traveling toward the grating, in a first direction parallel to a discharge direction between the discharge electrodes and in a second direction orthogonal to the discharge direction; and a holding platform that is formed as a component separate from the laser chamber and the grating, holds the beam expander optical system, and forms along with the beam expander optical system a beam expander unit.

A grating for line-narrowing a laser beam that is outputted from a laser apparatus at a wavelength in a vacuum ultraviolet region may include: a grating substrate; a first aluminum metal film formed above the grating substrate, the first aluminum metal film having grooves in a surface thereof; and a first protective film formed by an ALD method above the first aluminum metal film.