The main characteristics of the ENEA Discharge Produced Plasma (DPP) Extreme Ultraviolet (EUV) source are presented together with results of irradiations of various materials. The DPP EUV source, based on a Xe–plasma heated up to a temperature of 30 ÷ 40 eV, emits more than 30 mJ/sr/shot at 10 Hz rep. rate in the 10 ÷ 18 nm wavelength spectral range. The DPP is equipped with a debris mitigation system to protect particularly delicate components needed for patterning applications. The ENEA source has been successfully utilized for sub–micrometer pattern generation on photonic materials and on specifically designed chemically amplified resists. Details down to 100 nm have been replicated on such photoresists by our laboratory–scale apparatus for contact EUV lithography. Preliminary EUV irradiations of graphene films aimed at modifying its properties have been also performed.
We present a recently patented apparatus which consists of an extreme ultraviolet radiation source writing invisible
patterns on thin tags of alkali halides. The tags patterned using this method are almost impossible to counterfeit, and
offer a much better protection against fakes than available anti-counterfeiting techniques. We will discuss if this novel
technology is ready for industrial production of anti-counterfeiting tags.
Within a National Project on nanotechnologies, at the ENEA Research Centre in Frascati a micro-exposure tool for
projection lithography at 14.4 nm has been developed. The laser-plasma soft X-ray source is equipped with a patented
debris mitigation system developed in the frame of a European Integrated Project, in order to preserve the collecting
optics. A 90-nm-resolution patterning has been achieved on resist by this laboratory-scale tool based on a Schwarzschildtype
Within a National Project on nanotechnologies, a Micro-Exposure Tool (MET) for projection lithography at 14.4 nm,
based on a laser-produced plasma source, is being developed at the Frascati ENEA Center. The choice of this "exotic"
wavelength is due to the higher efficiency of a Debris Mitigation System (DMS) working in the interval of
approximately 14 nm < λ < 15 nm. It has to be noted that Mo/Si multilayer mirrors (MLM) can still have a high
reflectivity also at these wavelengths.
The solid-tape-target laser-generated plasma is driven by a XeCl excimer laser, with an optimized intensity of about
3•10<sup>10</sup> W/cm<sup>2</sup>, generating an extreme ultraviolet (EUV) source with a diameter of about 0.2 mm. Clearly, this kind of
source emits a lot of debris (both atomic and particulate types) and the 7-cm-far collector mirror must be protected
The paper is mostly devoted to the accurate and systematic study of these debris and to their reduction. The results of
mitigation efficiency obtained with a DMS prototype are very encouraging and lead to the design and patenting of its
We present the design elements and the preliminary experimental results of an Extreme-UltraViolet (EUV) exposure tool driven by the high-output-energy excimer laser-facility Hercules, which is aimed at printing a sub-100-nm-pattern on a photoresist in a single-shot irradiation.
The results of a numerical simulation of a conventional and a modified Schwarzschild objective are illustrated in relation with their use as imaging systems in an extreme ultraviolet lithography setup. It is demonstrated that the degradation of the resolution on the wafer due to the unavoidable tilt of the mask to the axis can fairly be vanished by a counter tilt of the wafer. In particular, it has been analysed the Schwarzschild objective setup under implementation at the ENEA Frascati Center within the context of the Italian FIRB project for EUV lithography.
The evolution operator formalism, combined with appropriate decomposition techniques of exponential operators, has revealed an effective strategy to treat evolution-like problems in both classical and quantum context. The continuous original equation is turned into a set of finite- difference equations, which preserve at a discrete level the basic features of the corresponding continuous model. The resulting scheme is easy to be encoded and demands for less computer time. The method can be applied to the paraxial gaussian optics, described by the 1D parabolic wave equation. Within this context, the formalism generates an explicit difference scheme, which provides a flexible numerical integration procedure, accounting for higher-order aberrations as well.
With the wavelet transform theory and the Markov random model, this paper presents an unsupervised multiresohition segmentation method to segment the textured SAR image. This method specially includes a step to estimate both the optimal number of texture classes and their model parameters without supervision. In order to interpret the results of the unsupervised segmentation as well as to understand the whole polarimetric SAR image, this paper also develops an interpretation approach which jointly utilizes the target decomposition theory and the identification technique of the scattering mechanism. Experimental results are presented for demonstration.
In this paper we intend to present some recent result obtained in our laboratory on excimer laser development and applications. Even if the activity has been initiated as long as 15 years ago after 1986, following the European Eurolaser Initiative, the programs were strengthened and enlarged to accommodate more ambitious goals, according to the increased attention to this field. Actually the activity includes the following: (1) development of source, (2) computer models, 3) special devices, and (4) applications. The description of our activity is presented according to the above mentioned order, with special attention to the most recent results.
The 1-D numerical code developed to model the performance of a high power excimer laser is described. The spectral method and the Rigrod equation are basic to the code, which is quite general for application to any two-mirror resonator geometry. The specific features of the code make it appropriate for analyzing laser resonators with high Fresnel numbers and accounting for gain medium nonhomogeneity and instability phenomena, as those arising in discharge pumped lasers.