摘要:
One or more operating characteristics of a light source are adjusted by estimating a plurality of extreme values of operating parameters of the light source while operating the light source under a set of extreme test conditions. For each extreme test condition, a group of pulses of energy is supplied to a first gas discharge chamber of the light source while operating the first gas discharge chamber under the extreme test condition to produce a first pulsed amplified light beam; a group of pulses of energy is supplied to a second gas discharge chamber of the light source while operating the second «as discharge chamber under the extreme test condition to produce a second pulsed amplified light beam. An extreme value of an operating parameter for the extreme test condition is measured to thereby estimate the extreme value of the operating parameter.
摘要:
The current invention concerns a laser beam generating device and a method for adjusting a wavelength of a laser beam. The current invention addresses the objective of further improving laser beam generation and wavelength adjustment. The current invention particularly allows for simplifying the combination of laser source elements such that they operate at different, but controlled, wavelengths with their beams overlapping. The laser beam generating device (100) comprises at least one laser source element (11) and an external cavity. The external cavity comprises an output coupler (40) and a periodic filter element (30) arranged between the laser source element (11) and the output coupler (40). The laser beam generating device further comprises at least two cut-off filter elements (21, 22) each arranged between the laser source element (11) and the periodic filter element (30).
摘要:
This application describes coupled and non-coupled opto-electronic oscillators with enhanced performance. Coupled OEOs implement a dispersion compensation mechanism to reduce dispersion-induced optical loss, a polarization control mechanism to reduce polarization-dependent optical loss, or a combination of the dispersion compensation mechanism and the polarization control mechanism to enhance the oscillator performance.
摘要:
In a first aspect, a lithography apparatus may comprise a mask designed using optical proximity correction (OPC), a pulsed laser source, and an active bandwidth control system configured to increase the bandwidth of a subsequent pulse in response to a measured pulse bandwidth that is below a predetermined bandwidth range and increase a bandwidth of a subsequent pulse in response to a measured pulse bandwidth that is above the predetermined bandwidth range. In another aspect an active bandwidth control system may include an optic for altering a wavefront of a laser beam in a laser cavity of the laser source to selectively adjust an output laser bandwidth in response to the control signal. In yet another aspect, the bandwidth of a laser having a wavelength variation across an aperture may be actively controlled by an aperture blocking element that is moveable to adjust a size of the aperture.
摘要:
Fast wavelenght correction equipment for an electric discharge laser includes at least one piezoelectic drive (80) and a fast wavelength measurement system and a fast feedback response time. In a preferred embodiment equipment is provided to control wavelength on a slow, intermediate amd fast time scales, which vary in range from several milliseconds to a few microseconds respectively. Techniques include a combination of a relatively slow stepper motor (82) and a very fast piezoelectric drive (80) for tuning the laser wavelength using a tuning mirror (14).
摘要:
The present invention provides an excimer laser capable of producing a high quality pulsed laser beam at pulse rates of about 4,000 Hz at pulse energies of about 5mJ or greater. A preferred embodiments is an ArF excimer laser specifically designed as a light source for integrated circuit lithography. An improved wavemeter with special software monitors output beam parameters and controls a very fast PZT driven tuning mirror and the pulse power charging voltage to maintain wavelength and pulse energy within desired limits. In a preferred embodiment two fan motors drive a single tangential fan which provides sufficient gas flow to clear discharge debris from the discharge region during the approximately 0.25 milliseconds between pulses.
摘要:
Fiber Bragg grating coupled light sources can acheive tunable single-frequency (single axial and lateral spatial mode) operation by correcting for a quadratic phase variation in the lateral dimension using an aperture stop. The output of a quasi-monochromatic light source such as a Fabry-Perot laser diode is astigmatic. As a consequence of the astigmatism, coupling geometries that accommodate the transverse numerical aperture of the laser are defocused in the lateral dimension, even for apsherical optics. The mismatch produces the quadratic phase variation in the feedback along the lateral axis at the facet of the laser that excites lateral modes of higher order than the TM00. Because the instability entails excitation of higher order lateral submodes, single frequency operation also is accomplished by using fiber Bragg gratings whose bandwidth is narrower than the submode spacing. This technique is particularly pertinent to the use of lensed fiber gratings in lieu of discrete coupling optics. Stable device operation requires overall phase match between the fed-back signal and the laser output. The fiber Bragg grating acts as a phase-preserving mirror when the Bragg condition is met precisely. The phase-match condition is maintained throughout the fiber tuning range by matching the Fabry-Perot axial mode wavelength to the passband center wavelength of the Bragg grating.