Laser produced plasma (LPP) systems have been developed as the primary approach for use in EUV scanner light sources for optical imaging of circuit features at 20nm nodes and beyond. This paper provides a review of development progress and productization status for LPP extreme-ultra-violet (EUV) sources with performance goals targeted to meet specific requirements from ASML. We present the latest results on power generation and collector protection for sources in the field operating at 10W nominal power and in San Diego operating in MOPA (Master Oscillator Power Amplifier) Prepulse mode at higher powers. Semiconductor industry standards for reliability and source availability data are provided. In these proceedings we show results demonstrating validation of MOPA Prepulse operation at high dose-controlled power: 40 W average power with closed-loop active dose control meeting the requirement for dose stability, 55 W average power with closed-loop active dose control, and early collector protection tests to 4 billion pulses without loss of reflectivity.
The usable power of high-power EUV light sources at 13.5 nm and also the lifetime of source and collector optics are currently considered to be the largest challenges encountered during the transition of EUV lithography from the current beta-tool status to high-volume manufacturing. Fraunhofer IOF Jena has developed cost-effective refurbishment technologies of multilayer-based near normal incidence collector mirrors for high-power laser-produced plasma sources. Presently, the collector mirror lifetime exceeds 80 billion laser pulses which correspond to a lifetime of several months during continuous use of the source. Together with their partners Cymer is currently carrying out a focused program to improve the collector lifetime. New multilayer coatings together with new in-situ cleaning strategies during source operation are key technology development strategies to get closer to the ultimate target of about one year collector lifetime. The paper discusses different LPP collector refurbishment strategies and presents the recent status on collector refurbishment techniques.
The usable power and the collector optics lifetime of high-power extreme ultraviolet light sources at 13.5 nm are considered as the major challenges in the transitioning of EUV lithography from the current pre-production phase to high volume manufacturing. We give a detailed performance summary of the large ellipsoidal multilayer collector mirrors used in Cymer's laser-produced plasma extreme ultraviolet light sources. In this paper we present the optical performance - reflectance and wavelength - of the multilayer-coated ellipsoidal collectors as well as a novel approach for the roughness characterization of large EUV mirror optics based on light scattering measurements at 442 nm. We also describe the optical performance and characteristics during operation of the light source and the substantial increase of collector lifetime by the implementation of new coating designs.
CdSe and ZnS core-shell nanoparticles made by LAM (Laser Ablation of Microparticles) show photoluminesence (PL) peaks in a region of wavelengths around 400 rim. Control over the size and PL peak position is obtained by irradiating the nanoparticles multiple times. In LAM, micropaticle powder passes through an aerosol generator and then into a laser ablation glass cell, where a laser pulse (high energy excimer laser) ablates the microparticle aerosol. Nanoparticles are formed after condensation. At this stage the nanoparticles can be covered with a second material or irradiated multiple times to change their size. The size distribution of these particles is Successfully investigated with TEM (Transmission Electron Microscopy). PL blue shifts are seen as the mean size decreases.