The CHIRP II High-power Excimer Laser

Fieret, Jim; Heath, Robert M.; Lawrence, A.; Osborne, M. R.; Osbourn, S. J.; Stamatakis, T.; Winfield, Richard Dien

doi:10.1080/09500349414551121

Cited by 5 publications

(4 citation statements)

References 2 publications

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“…As the effect of a damper largely depends on the discharge conditions, further investigations are needed. 21,22 On the other hand, a conventional power supply switched by a thyratron was not suitable for a HRR excimer laser due to the short lifetime and the unstable switching. There have been many attempts to replace a thyratron by high-power semiconductor switching devices such as thyristors.…”

Section: Shock Wave Damping and Othersmentioning

confidence: 99%

Development of key components and technologies for a high repetition rate and high-power excimer laser

Goto

Takagi

Kakizaki

et al. 1998

Review of Scientific Instruments

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Articles you may be interested inThe influence of the pulse length on the drilling of metals with an excimer laser Key components and technologies have been developed for an ultrahigh repetition rate XeCl excimer laser of 5 kHz to be used for industrial applications. A compact axial blower having a revolution rate of up to 10 000 min Ϫ1 and a maximum pressure of 16.2 kPa in air was made with a canned magnetic coupler to circulate a laser gas at a flow velocity of over 150 m/s in a discharge region. Materials constituting a laser chamber were tested to prevent discharge instability by gas contamination to enable long time operation. The dominant cause of the instability was investigated by a simple simulation. For a preionization, a novel sealed-off x-ray tube was developed to compare the suitability in a high repetition rate operation with that of conventional UV preionization. The gas due to the shock and acoustic waves generated by discharge pulses was measured to design the damper, which enabled the suppression of the gas turbulence by around a tenth. To simplify cumbersome laser maintenance, a new power supply provided by a novel fast switching semiconductor device was evaluated by operating the laser. The experimental laser apparatus integrating these key components and technologies was operated to confirm the practical availability for high repetition of up to 5 kHz. Many kinds of basic experiments have been performed to increase repetition rate, average power, and reliability. Though these experimental results have not yet been integrated and performed simultaneously, we have achieved operation up to an average output power of 0.56 kW at 5 kHz. Based on the results and empirical knowledge, the prospect for a practical high repetition rate excimer laser was discussed.

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Section: Shock Wave Damping and Othersmentioning

confidence: 99%

Development of key components and technologies for a high repetition rate and high-power excimer laser

Goto

Takagi

Kakizaki

et al. 1998

Review of Scientific Instruments

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“…3 In the past two decades, the flow field developing process after discharge in the chamber and its influence to the next discharge have attracted the attentions of scientists and Engineers for the increasing high-repetitive-rate and stable-discharge demands of repetitively pulsed gas laser application, especially the EUV Lithography application. 4,5,10 The schlieren 6,10 , shadowgraph 11 , and interferometry 5,7 were all applied, and the images of three kinds of shock waves (the longitudinal shock waves in the gas flow direction, the transversal shock waves between the electrodes and the transversal shock waves between optics) were obtained 7,11 . However, most of these works were qualitative or semi-quantitative 5,7,10,11 .…”

Section: Introductionmentioning

confidence: 99%

“…4,5,10 The schlieren 6,10 , shadowgraph 11 , and interferometry 5,7 were all applied, and the images of three kinds of shock waves (the longitudinal shock waves in the gas flow direction, the transversal shock waves between the electrodes and the transversal shock waves between optics) were obtained 7,11 . However, most of these works were qualitative or semi-quantitative 5,7,10,11 . Furthermore, the shortest exposure time of traditional CCD or COMS camera limited the transient observation of the whole chamber, which restricted the application of imaging technique in the flow field temporal analysis.…”

Section: Introductionmentioning

confidence: 99%

Evolution of shock wave in TEA gas laser

Yang

et al. 2010

SPIE Proceedings

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The evolution of shock wave generated by discharge in laser chamber is one of the key factors which affect laser beam quality, discharge stability, and repetition rate of TEA gas laser. In this paper, Mach-Zehnder interferometer is applied to observe both the longitudinal and transversal shock waves between electrodes as well as the acoustic waves originated by preionization in the discharge pumping zone of TEA gas laser. By changing the discharge voltage, gas pressure and gas composition concentration, the developing processes in different conditions are compared and analyzed. It is observed that the shock waves originating from cathode is different from the anode's ones even in the symmetric electrode construction. And the carbon dioxide concentration in helium-buffered working gas can affect the speed of the wave obviously. However, the increasing trend of shock wave speed, when increasing discharge voltage or reducing discharge gas pressure, is inconspicuous.

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“…The final target, which was to demonstrate more than 5 kHz operation with an average output a͒ Present address: Dept. 8 Meanwhile, several attempts to create an excimer laser by using a power supply provided by a semiconductor switching device have been reported. b͒ Present address: Dept.…”

Section: Introductionmentioning

confidence: 99%

Design concept and performance considerations for fast high power semiconductor switching for high repetition rate and high power excimer laser

Goto

Kakizaki

Takagi

et al. 1997

Review of Scientific Instruments

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Development of key components and technologies for a high repetition rate and high-power excimer laser Rev.A high current, battery-operated power supply with power control through an on-off fast switch Rev.A semiconductor switching power supply has been developed, in which a novel structure semiconductor device, metal-oxide-semiconductor assisted gate-triggered thyristor ͑MAGT͒ was incorporated with a single stage magnetic pulse compression circuit ͑MPC͒. The MAGT was specially designed to directly replace thyratrons in a power supply for a high repetition rate laser. Compared with conventional high power semiconductor switching devices, it was designed to enable a fast switching, retaining a high blocking voltage and to extremely reduce the transient turn-on power losses, enduring a higher peak current. A maximum peak current density of 32 kA/cm 2 and a current density risetime rate di/dt of 142 kA/͑cm 2 ϫs͒ were obtained at the chip area with an applied anode voltage of 1.5 kV. A MAGT switching unit connecting 32 MAGTs in series was capable of switching on more than 25 kV-300 A at a repetition rate of 5 kHz, which, coupled with the MPC, was equivalent to the capability of a high power thyratron. A high repetition rate and high power XeCl excimer laser was excited by the power supply. The results confirmed the stable laser operation of a repetition rate of up to 5 kHz, the world record to our knowledge. An average output power of 0.56 kW was obtained at 5 kHz where the shortage of the total discharge current was subjoined by a conventional power supply with seven parallel switching thyratrons, simultaneously working, for the MAGT power supply could not switch a greater current than that switched by one thyratron. It was confirmed by those excitations that the MAGT unit with the MPC could replace a high power commercial thyratron directly for excimer lasers. The switching stability was significantly superior to that of the thyratron in a high repetition rate region, judging from the discharge current wave forms. It should be possible for the MAGT unit, in the future, to directly switch the discharge current within a rise time of 0.1 s with a magnetic assist.

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The CHIRP II High-power Excimer Laser

Cited by 5 publications

References 2 publications

Development of key components and technologies for a high repetition rate and high-power excimer laser

Development of key components and technologies for a high repetition rate and high-power excimer laser

Evolution of shock wave in TEA gas laser

Design concept and performance considerations for fast high power semiconductor switching for high repetition rate and high power excimer laser

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