Cymer, Inc.

John T Melchior

Richard L Sandstrom

Peter Clarke Newman

Holger K Glatzel

Rajasekhar Rao

William N Partlo

Richard G Morton

Richard M Ness

Thomas Patrick Duffey

Xiaojiang Jason Pan

Herve A Besaucele

Eric Anders Mason

Toshihiko Ishihara

Daniel Anthony Rothweil

Raymond F Cybulski

Alexander Igorevich Ershov

Palash P Das

Robert Jay Rafac

Richard C Ujazdowski

Thomas Hofmann

R Kyle Webb

David J Warkentin

John Martin Algots

Thomas A Yager

Walter Dale Gillespie

Vladimir B Fleurov

Rostislav Rokitski

William G Hulburd

Gamaralalage G Padmabandu

James K Howey

Alex P Ivaschenko

Jean-Marc Hueber

Russell Allen Burdt

William N Partio

Leonard Lublin

Kuo-Tai Teng

Elizabeth Marsh

Matthew Ball

Holzer K Glatzel

Saptaparna Das

Rabin Paudel

Rajasekhar M Rao

Hoger K Glatzel

Rahasekhar Rao

A light source apparatus includes a chamber and a metal fluoride trap coupled to the chamber and configured to provide clean gas to a set of window housing apparatuses coupled to the chamber. Each window housing apparatus is configured to reduce metal fluoride dusting on an optical window and includes a window housing supporting an optical window, an aperture apparatus coupled to the window housing, and an insert disposed between the aperture apparatus and the optical window. The aperture apparatus includes a plurality of cells configured to trap metal fluoride dust flowing upstream from the chamber through the aperture apparatus toward the optical window. The insert is configured to control a first flow rate of the clean gas along the optical window and a second flow rate of the clean gas through the aperture apparatus.

Directed gas purge to reduce dusting of excimer discharge chamber windows

Apparatus for and methods of combining multiple, i.e., two or more laser beams to reduce even to the point of elimination a transverse gap between the two or more beams caused, for example, by a space between a coating on a surface of the mirror and the edge of the mirror, or by optic geometry, is avoided.

Apparatus for and methods of combining multiple laser beams

Information relating to an etalon is accessed, the etalon being associated with a calibration parameter having a pre-set default value, the etalon being configured to produce an interference pattern including a plurality of fringes from a received light beam, and the information relating to the etalon including first spatial information related to a first fringe of the plurality of fringes and second spatial information related to a second fringe of the plurality of fringes. A first wavelength value of the received light beam is determined based on the spatial information related to the first fringe and an initial value of the calibration parameter. A second wavelength value of the received light beam is determined based on the spatial information related to the second fringe and the initial value of the calibration parameter. The first wavelength value and the second wavelength value are compared to determine a measurement error value.

Determination of measurement error in an etalon

An optical element for a deep-ultraviolet light source includes a crystalline substrate; a coating on an exterior surface of the crystalline substrate, the coating having a thickness along a direction that extends away from the exterior surface; and a structure on and/or in the coating, the structure including a plurality of features that extend away from the crystalline substrate along the direction. The features include an amorphous dielectric material and are arranged such that an index of refraction of the structure varies along the direction.

Optical element for a deep ultraviolet light source

An attenuation optical system is in a beam path of a light beam traveling through a regenerative ring resonator. The attenuation optical system includes an actuator configured to receive an electromagnetic signal; and a plate mounted to the actuator to be moveable between a plurality of positions, with each position placing an attenuation region in the beam path such that the beam profile is covered by the attenuation region and each attenuation region representing an attenuation factor applied to the light beam as determined by a geometry of the attenuation region. At least one attenuation region includes a plurality of evenly-spaced elongated openings between solid energy-reflecting surfaces and at least one attenuation region includes an open area that is larger than the beam profile of the light beam.

Intracavity loss element for power amplifier

An optical configuration to illuminate an etalon in a laser wavemeter with a minimum level of light intensity. The system includes optical components to direct a portion of the laser output beam representing the entire cross section of the beam, through an etalon positioned in an etalon housing and onto a photodetector. A first lens condenses the size of the beam sample, and a second lens re-collimates the beam which then passes into the etalon housing, ensuring that all of the spatial components of the beam are adequately sampled. A diffractive diffusing element is incorporated into the optical path. In a preferred embodiment, the diffractive diffusing element is placed within the etalon housing between said plano-concave lens and the etalon. In another preferred embodiment, the diffusing element is located up stream but outside the housing in the optical path.

Wavemeter for gas discharge laser

A wavemeter and method for measuring bandwidth for a high repetition rate gas discharge laser having an output laser bean comprising a pulsed output of greater than or equal to 15 mJ per pulse, sub-nanometer bandwidth tuning range pulses having a femptometer bandwidth precision and tens of femptometers bandwidth accuracy range, for measuring bandwidth on a pulse to pulse basis at pulse repetition rates of 4000 Hz and above, is disclosed which may comprise a focusing lens having a focal length; an optical interferometer creating an interference fringe pattern; an optical detection means positioned at the focal length from the focusing lens; and a bandwidth calculator calculating bandwidth from the position of interference fringes in the interference fringe pattern incident on the optical detection means, defining a Dand a D, the respective distances between a pair of first fringe borders and between a pair of second fringe borders in the interference pattern on an axis of the interference pattern, and according to the formula &#x394;&#x3bb;=&#x3bb;[D&#x2212;D]/[8f&#x2212;D], where &#x3bb;is an assumed constant wavelength and D=(D&#x2212;D)/2, and f is the focal length. The optical detector may be a photodiode array. The wavemeter may have an optical interferometer having a slit function; the slit function and the focal length being selected to deliver to the optical detector the two innermost fringes of the optical interference ring pattern. The optical detector may comprise an array of pixels each having a height and width and the array having a total width; and an aperture at the optical input to the optical interferometer may selectively input to the optical interferometer a portion of a beam of light sufficient for the output of the etalon to illuminate the optical detector over the height of each respective pixel height and the total width. The optical interferometer may comprise an etalon having a slit function of 3 pm or less and a finesses of 25 or greater; and the focal length may be 1.5 meters. A second stage diffuser may be placed between the first stage diffuser and the etalon delivering a narrow cone of light to the etalon, and an aperture between the second stage diffuser and the etalon may deliver to the etalon a thin strip of the narrow cone of light.

Gas discharge MOPA laser spectral analysis module

A wavemeter and method for measuring bandwidth for a high repetition rate gas discharge laser having an output laser bean comprising a pulsed output of greater than or equal to 15 mJ per pulse, sub-nanometer bandwidth tuning range pulses having a femptometer bandwidth precision and tens of femptometers bandwidth accuracy range, for measuring bandwidth on a pulse to pulse basis at pulse repetition rates of 4000Hz and above, is disclosed which may comprise a focusing lens having a focal length; an optical interferometer creating an interference fringe pattern; an optical detection means positioned at the focal length from the focusing lens; and a bandwidth calculator calculating bandwidth from the position of interference fringes in the interference fringe pattern incident on the optical detection means, defining a Dand a DO, the respective distances between a pair of first fringe borders and between a pair of second fringe borders in the interference pattern on an axis of the interference pattern, and according to the formula &#x394;&#x3bb;=&#x3bb;[D&#x2212;D]/[8f&#x2212;D], where &#x3bb;is an assumed constant wavelength and D=(D&#x2212;D)/and f is the focal length. The optical detector may be a photodiode array. The wavemember may have an optical interferometer having a slit function; the slit function and the focal length being selected to deliver to the optical detector the two innermost fringes of the optical interference ring pattern. The optical detector may comprise an array of pixels each having a height and width and the array having a total width; and an aperture at the optical input to the optical interferometer may selectively input to the optical interferometer a portion of a beam of light sufficient for the output of the etalon to illuminate the optical detector over the height of each respective pixel height and the total width. The optical interferometer may comprise an etalon having a slit function of 3 pm or less and a finesses of 25 or greater; and the focal length may be 1.5 meters. A second stage diffuser may be placed between the first stage diffuser and the etalon delivering a narrow cone of light to the etalon, and an aperture between the second stage diffuser and the etalon may deliver to the etalon a thin strip of the narrow cone of light.

The present invention provides long life optics for a modular, high repetition rate, ultraviolet gas discharge laser systems producing a high repetition rate high power output beam. The invention includes solutions to a surface damage problem discovered by Applicants on CaFoptics located in high pulse intensity sections of the output beam of prototype laser systems. Embodiments include an enclosed and purged beam path with beam pointing control for beam delivery of billions of output laser pulses. Optical components and modules described herein are capable of controlling ultraviolet laser output pulses with wavelength less than 200 nm with average output pulse intensities greater than 1.75&#xd7;10Watts/cmand with peak intensity or greater 3.5&#xd7;10Watts/cmfor many billions of pulses as compared to prior art components and modules which failed after only a few minutes in these pulse intensities. Techniques and components are disclosed for minimizing the potential for optical damage and for reducing the pulse energy density to less than 100&#xd7;10J/cm. Important improvements described in this specification have been grouped into the following subject matter categories: (1) Solution to CaFsurface damage discovered by Applicants, (2) description of a high power ArF MOPA laser system, (3) description of beam delivery units, (4) polarization considerations (5) a high speed water-cooled auto shutter energy detector module and (6) other improvements.

High power deep ultraviolet laser with long life optics

A spectral analysis module, including a wavemeter, for a high repetition rate gas discharge laser having a laser output beam comprising a pulsed output of greater than or equal to 15 mJ per pulse, sub-nanometer bandwidth tuning range pulses having a femptometer bandwidth precision and tens of femptometers bandwidth accuracy range, for measuring bandwidth on a pulse to pulse basis at pulse repetition rates of 4000 Hz and above, is disclosed which may comprise a primary beam-splitter in the path of the laser output laser of the gas discharge laser operative to pass the vast majority of the output beam and to reflect a first small portion of the output beam, the primary beam splitter oriented at an angle to sufficiently reduce the fluence on the primary beam-splitter, and creating overlapping fresnel reflections in the first small portion of the laser output beam; a secondary beam splitter made from a material having a damage threshold sufficiently high to tolerate the fluence created by the overlapping portion of the fresnel reflections in the first small portion of the output laser beam, the secondary beam splitter reflecting the vast majority of the first small portion of the output laser beam and passing a second small portion of the output laser beam; a telescoping optic in the path of the second small portion of the output beam operative to demagnify the second small portion of the output beam onto a first stage diffuser receiving the demagnified second small portion of the output laser beam, the demagnification selected to keep the fluence in the overlapping fresnel reflections in the second small portion of the output laser beam below the damage threshold of the first stage diffuser. The telescoping optic may demagnify a long axis of the second small portion of the output laser beam more than a short axis of the second small portion of the output laser beam, redistributing the fluence of the second small portion of the laser output beam across the first stage diffuser to keep any portion of the first stage diffuser from exceeding the damage threshold for the material from which the first stage diffuser is made. The vast majority of the first small portion of the laser output beam may be reflected into a power detection module. A second stage diffuser may creating a narrow cone of a focused second small portion of the laser output beam before the beam enters an interferometer.

The present invention provides a gas discharge ultraviolet laser capable of producing a high quality pulsed ultraviolet laser beam at pulse rates greater than 2000 Hz at pulse energies at 5 mJ or greater and having an enclosed beam path at least a portion of which comprises an oxidation agent. In a preferred embodiment a portion of the beam path comprises a sealed chamber containing a gas comprising a small concentration of oxygen. In one preferred embodiment the sealed chamber is an etalon chamber and the contained gas is nitrogen with an oxygen concentration of between 1.6 and 2.4 percent. In another preferred embodiments a small concentration of oxygen is added to the purge gas of a special purge compartment containing optical components exposed to high intensity output laser beam.

Gas discharge ultraviolet laser with enclosed beam path with added oxidizer

An excimer laser with a purged beam path capable of producing a high quality pulsed laser beam at pulse rates in excess of 2,000 Hz at pulse energies of about 5 mJ or greater. The entire purged beam path through the laser system is sealed to minimize contamination of the beam path. A preferred embodiment comprises a thermally decoupled LNP aperture element to minimize thermal distortions in the LNP. This preferred embodiment is an ArF excimer laser specifically designed as a light source for integrated circuit lithography. An improved wavemeter is provided with a special purge of a compartment exposed to the output laser beam.

Gas discharge laser with improved beam path

The present invention provides a wavemeter for an ultraviolet laser capable of long life beam quality monitoring in a pulsed ultraviolet laser system at pulse rates greater than 2000 Hz at pulse energies at 5 mJ or greater. In a preferred embodiment an enhanced illumination configuration reduces per pulse illumination of an etalon by a factor of 28 compared to a popular prior art configuration. Optics are provided in this embodiment which reduce light entering the etalon to only that amount needed to illuminate a linear photo diode array positioned to measure interference patterns produced by the etalon. In this preferred embodiment two sample beams produced by reflections from two surfaces of a beam splitter are diffused by a defractive diffuser and the output of the defractive diffuser is focused on two separate secondary diffusers effectively combining both beams in two separate spectrally equivalent diffuse beams. One beam is used for wavelength and bandwidth measurement and the other beam is used for calibration. In preferred embodiments an etalon chamber contains nitrogen with an oxygen concentration of between 1.6 and 2.4 percent.

Gas discharge ultraviolet wavemeter with enhanced illumination

Reliable, modular, production quality narrow-band high rep rate ArF excimer laser

Growing community of inventors

San Diego, CA, United States of America

John T Melchior