High-efficiency clean EUV plasma source at 10–30 nm, driven by a long-pulse-width excimer laser (original) (raw)
Related papers
EUV laser produced plasma source development for lithography (Invited Paper
2005
The ideal source of radiation for extreme ultraviolet lithography will produce intense light in a 2% bandwidth centred at 13.5 nm, while the debris and out-of-band radiation produced will be limited to prevent adverse effects to the multilayer optics in the lithography system. In this study ways to optimise plasma sources containing tin are presented. The optimum power density for a tin slab target, with a fixed spotsize, is determined, while the effects of power density on ceramic targets, where tin is present only as a few percent in a target of mainly low Z elements, is also investigated. It has been found that the in-band radiation is increased when the concentration is 5-6%, while the out-of-band radiation is dramatically reduced, due the the low average Z of the target constituents, with conversion effciencies of over 2.5% recorded. The power density needed to optimise the emission from ceramic targets was found to be greater than that required for the pure tin case. In addition, if the target is first irradiated with a pre-pulse, the conversion effciency is seen to increase.
Excimer-Laser-Driven EUV Plasma Source for Single-Shot Projection Lithography
IEEE Transactions of Plasma Science 37, 475-480 (2009), 2009
We present a low-cost microexposure tool for projection lithography at 14.4 nm we have designed and operatedat the ENEA Research Centre, Frascati. It is a laboratory-scale system based on a Schwarzschild-type projection optics which uses a laser-plasma soft X-ray source, equipped with a patented debris mitigation system in order to preserve the collector optics. As a preliminary result, we achieved a 90-nm optical resolution patterning on commercial resist. A sharp improvement in resolution size is expected when operating this tool by a large-output energy excimer laser in order to obtain a single-shot patterning
Applied Physics B-lasers and Optics, 2010
The paper describes a debris-free, efficient laser-produced plasma source emitting EUV radiation. The source is based on a double-stream Xe/He gas-puff. Its properties and spectroscopic signatures are characterized and discussed. The spatio-spectral features of the EUV emission are investigated. We show a large body of results related to the intensity and brightness of the EUV emission, its spatial, temporal, and angular behavior and the effect of the repetition rate as well. A conversion efficiency of laser energy into EUV in-band energy at 13.5 nm of 0.42% has been gained. The electron temperature and electron density of the source were estimated by means of a novel method using the FLY code. The experimental data and the Hullac code calculations are compared and discussed. The source is well suited for EUV metrology purposes. The potential of the source for application in EUV lithography was earlier demonstrated in the optical characterization of Mo/Si multi-layer mirrors and photo-etching of polymers.
Applied Surface Science 272 (2013) 13–18, 2013
While developing a laboratory-scale micro-exposure tool for extreme ultraviolet (EUV) projection lithography which uses a laser-produced plasma emitting EUV pulsed radiation, we faced the problem of suppressing the various debris (ions, neutrals, particulate, clusters, droplets) emitted by the plasma target. The suppression of debris is a crucial task in the frame of EUV projection lithography, mainly because debris seriously limit both lifetime and performance of the expensive optics and filters put close to the plasma source. In this paper we present the experimental measurements of main debris characteristics (velocity, size, charge, momentum, spectral energy, spatial distribution). Then, we present the operating results of a patented debris mitigation system (DMS) specifically designed to suppress debris with the measured characteristics. We achieved reduction factors ∼ 800 for atoms and nm-size clusters, and ∼ 1600 for particles larger than 500 nm. These results are at the forefront in this field. The excellent performance of our DMS was a breakthrough to achieve a 90-nm patterning on commercial resists by our micro-exposure tool EUV projection lithography.
Laser plasma EUVL sources: progress and challenges
Emerging Lithographic Technologies VIII, 2004
The most pressing technical issue for the success of EUV lithography is the provision of a high repetition-rate source having sufficient brightness, lifetime, and with sufficiently low off-band heating and particulate emissions characteristics to be technically and economically viable. We review current laser plasma approaches and achievements, with the objective of projecting future progress and identifying possible limitations and issues requiring further investigation.
Xenon Discharge-Produced Plasma Radiation Source for EUV Lithography
IEEE Transactions on Industry Applications, 2000
Extreme ultraviolet (EUV) radiation with wavelengths of 11-14 nm is seen as the most promising candidate for a new lithographic technology. Compared with synchrotron radiation sources and laser-produced plasmas, gas dischargeproduced plasma sources for EUV radiation are expected to offer lower cost of ownership. Using xenon, a broadband emission in the investigated wavelength range from 10 to 17 nm is observed. Very short current pulses, having a fast rise time of 85-or 140-ns duration and 23-kA amplitude, were applied across the xenon-filled Z-pinch capillary (3-mm diameter and 5-mm length) to produce EUV radiation. An EUV radiation from the Z-pinch plasma was characterized, which is based on the temporal behavior of EUV intensity and the pinhole images. Two maximum EUV radiations occur, which are sensitive to the xenon flow rate and the discharge current. The first radiation is relatively of short duration, while the second radiation lasts as long as the first period of the current flows. The EUV source size due to the first radiation is approximately 300 µm, i.e., half of the one due to the second radiation.
A gas discharged based radiation source for EUV-lithography
Microelectronic Engineering, 1999
A new high repetitive, compact and low cost gas discharge based EUV ,,lamp" has been studied as an alternative to laser-produced plasmas as EUV sources. First results using oxygen in a fast discharge of electrically stored energy around 1 J lead to a conversion efficiency of about 0.1% for the emission at 13.0 nm which is suited for the use with Mo/Si-multilayer mirrors. Using Xenon a broadband emission in the investigated wavelength range from 10 nm to 18 nm is observed. With a first version a source with 40 W electrical input power could be demonstrated that emits about 50 mW/(4nsr) around 13 nm at a repetition rate of 150 Hz. No debris and no electrode erosion was observed after more than 107 pulses done up to now. Making use of the remaining optimisation potential this concept seems to be promising to fulfil the requirements of extremeultraviolet lithography
Preliminary results from key experiments on sources for EUV lithography
Microelectronic Engineering, 2001
While huge progress has been achieved for EUVL system design and multilayer optics during the last years the decision on the best suited source is still open. In a German basic research cooperation on short-wavelength plasma based sources some key issues also relevant for EUVL are addressed: the comparison of existing sources, investigations on the scalability of source concepts and the demonstration of key features. Preliminary results of investigations on parameters for best conversion efficiency of laser produced plasmas, concepts for high-power lasers and scalability of gas discharge based sources are presented. Comparability of results is assured by calibrated metrology tools which are cross checked with ASML's flying circus.