High Brightness and Power Diode Pumped Nd:YAG Laser is the engine for Laser Produced X-ray (LPX). The LPX system consists of a compact diode pumped Nd:YAG laser system which produces brightness in excess of 1015 W/cm2 on target at up to 300 watts average power (4 parallel beams). The MOPA (Master Oscillator Power Amplifier) laser system delivers 250 mJ/pulse @ 300 Hz per beam (75 W average). 4 beams system at 300 W average power was demonstrated. The high brightness is achieved using ~800 ps pulse duration and near diffraction limited beam quality. Very high conversion efficiency (~9%) into 2π sr from 1064 nm laser output to 1 nm broadband x-ray was demonstrated using copper tape target. 1 nm x-rays were used for proximity x-ray lithography and demonstrated feature size resolution down to 75 nm. Narrow linewidth x-ray (λ/Δλ~600) has also been demonstrated with 1% conversion efficiency from 532 nm to 3.37 nm using Mylar tape target for compact high resolution and contrast x-ray tomography for biological cells. A unique mechanical shutter was developed to stop all the ablated debris from the target material that can damage and contaminate the fragile x-ray optics.
Soft x-rays have wavelengths in the range of 1-15 nm and therefore the diffraction limited spot size of focused x-rays can be as small as 1.22 x the radiation wavelength, or less than 20 nm spot size. Using our pulsed x-ray source and focusing a small collected solid angle of this x-ray radiation to a sample provides enough power to form a very hot plasma that emits a range of radiation from UV through IR that can be collected and analyzed on a conventional optical spectrometer. In addition to diagnostic capabilities the instrument can be also used as a tool to form structures at nanometer scale resolution. Since the plasma is formed by ablating the target material with x-rays the target can be patterned or nanomachined using the plasma itself. It should be possible to pattern nanoscale devices by rastering the material under the nanoplasma. Finally in analogy to plasma assisted CVD processes, organometallic vapors could introduced into the sample chamber such that the nanoplasma locally plates out specific species of metals of other materials on the target at nanoscale sizes for forming devices, circuits, wires, etc. This paper presents a design for a nanoplasma instrument, predicted performance parameters will be presented, and development issues identified and discussed.
JMAR develops Laser-Produced Plasma (LPP) sources for lithography applications, and has specifically developed Collimated laser-Plasma Lithography (CPL) as a 1 nm collimated point source and stepper system to address sub-100nm lithography needs. We describe the CPL source development, show demonstrated sub-100nm printing capability, and describe status of a beta lithography tool. The system will be power-scaled to address silicon device contacts and vias at 90nm and below. This development has much in common with LPP Extreme UltraViolet Lithography (EUVL) sources; an EUV source concept is presented to address the high power requirements of that Next Generation Lithography (NGL).
One of the key leverage factors in determining the viability of laser-plasma sources for EUVL is the conversion efficiency of laser light to EUV emission in the 13-nm region. We describe experiments and theoretical calculations on a mass-limited laser target design using tin that offers high conversion efficiency.
Celestino Gaeta, Harry Rieger, I. C. Edmond Turcu, Richard Forber, Kelly Cassidy, S. Campeau, Michael Powers, J. Maldonado, James Morris, Richard Foster, Henry Smith, M. Lim
A compact x-ray source radiates 24 Watts average power of 1nm x-rays in 2 (pi) steradians. The laser produced plasma x-ray source has a 300 W laser driver which is a compact, diode-pumped solid-state Nd:YAG laser system. The x-ray conversion efficiency is 9 percent of the laser power delivered on target. The x-ray source was used to demonstrate x-ray lithography of 75 nm lines. The x-ray source is optimized for integration with a x-ray stepper to provide a complete x-ray lithography exposure tool for the manufacture of high-speed GaAs devices.
Celestino Gaeta, Harry Rieger, I. C. Edmond Turcu, Richard Forber, S. Campeau, Kelly Cassidy, Michael Powers, Robert Grygier, Juan Maldonado, G. French, Joe Naunguyan, Charles Kelsy, Peter Hark, James Morris, Richard Foster
A compact laser produced plasma x-ray source radiates 24 Watts average power of 1nm x-rays in 2(pi) steradians. The x-ray power conversion efficiency is 9% from the laser average power focused on the x-ray target. The laser-plasma x-ray source is generated by a 300W compact, diode-pumped, solid-state Nd:YAG laser system. The tabletop laser system is constructed on a 4ft x 8ft optical bench and the laser modules are 1ft high. The total wall-plug power consumption for this laser-produced-plasma x-ray source is 22 kW. The x-ray source is optimized for integration with and x-ray stepper to provide a complete x-ray lithography exposure tool for the manufacture of high speed GaAs devices.
A high power picosecond soft x-ray source is generated by a compact, modular, diode pumped solid state laser BriteLightTM. Three x-ray source version are constructed from laser modules with increasing power. The power of the x-ray sources is tailored to potential applications. The building block of such a modular system is a 3 Watt x-ray power source with 1.1 keV x-ray photon energy. The laser system is very compact with dimensions of 4 ft X 3 ft X 1 fit. It is composed of a laser master oscillator, pre-amplifier and one power amplifier. A four laser amplifier system was also constructed in order to generate 12 W of x-rays for application to x-ray lithography.
I. C. Edmond Turcu, Richard Forber, Robert Grygier, Harry Rieger, Michael Powers, S. Campeau, G. French, Richard Foster, Phillip Mitchell, Celestino Gaeta, Z. Cheng, Jay Burdett, David Gibson, Stephen Lane, Troy Barbee, Stanley Mrowka, Juan Maldonado
An x-ray power of 2.8 Watts at the 1 nm x-ray lithography wavelength was generated by a copper plasma formed by a single laser beam focused to an intensity of greater than 1014 W/cm2 on a copper tape target. The all solid state BritelightTM YAG laser has 700 ps pulse duration, 300 Hz pulse repetition rate, average power of 75 Watts, and less than 2 times diffraction limited beam quality at the fundamental 1.064 micrometer wavelength. The single beam laser system has a master oscillator, a preamplifier and one power amplifier, all diode pumped. Measurements confirmed negligible copper vapor debris at 8 cm from the laser-plasma source with atmospheric pressure He gas and modest gas flow. The point source x-ray radiation was collimated with either a polycapillary or grazing mirror collimator. The near-parallel beam of x-rays has good divergence both globally (0.5 mrad) and locally (less than 3 mrad), good uniformity (2% achievable goal) and large uniform field size (20 mm X 20 mm full field and 25 mm X 36 mm scanning system). High-resolution lithography was performed for the first time with collimated 1 nm point source x-rays. A power scaling system is being built with eight amplified beams in parallel on the x-ray target, and is expected to achieve 24 - 30 Watts of x-rays. A 16 beam laser plasma x-ray lithography system could achieve a throughput of 24 wafer levels per hour using 300 mm diameter wafers.
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