Papers

AVS2001 Session TF+NS+SE+VST-MoA: Nanophase & Multilayered Thin Films

Monday, October 29, 2001 2:40 PM in Room 123

Monday Afternoon

Start	Invited?	Item
2:40 PM		TF+NS+SE+VST-MoA-3 Precision Multilayered Thin Films for Manufacturing of the Next Generation of Computer Chips E Spiller (Lawrence Livermore National Laboratory) Lithographic cameras for the fabrication of circuits below 70 nm line width can not use lenses because no transparent material exists for the required short wavelengths in the ultraviolet. Extreme Ultraviolet (EUV) lithography with wavelengths around 13 nm using multilayer coated mirrors is a main contender for chips with line widths between 30 and 70 nm. Meeting the one Angstrom tolerances on the figure and smoothness of the optical surfaces before and after the multilayer deposition and controlling the profile of the multilayer period to better than 0.1 Angstrom has been a major challenge. The talk will give an update on the status of EUV lithography with emphasis on the fabrication, characterization and understanding of the required film deposition processes.
3:20 PM		TF+NS+SE+VST-MoA-5 Ion Beam Growth and Properties of SiN/TiN Multilayer Thin Films for Phase-shift Masks in Optical Lithography P.F. Carcia, M.H. Reilly (DuPont Central Research and Development); L.J. Pilione, R.F. Messier (Pennsylvania State University); L. Dieu (DuPont Photomask); R.S. McLean (DuPont Central Research and Development) Today's high speed microprocessors and dense memory chips are the result of modern optical lithography that allows printing smaller and smaller circuit features on a Si wafer. In 2002, optical lithographic tools with imaging radiation of 193 nm will produce leading edge devices with sub 100 nm critical dimensions. The continued success of optical lithography, which has delayed the introduction of next generation technologies with X-rays, ions, or electrons, can be attributed to the innovative application of optical resolution enhancement techniques that improve feature resolution and increase process latitude. One of these, the attenuating phase-shift mask (attPSM) improves image contrast with destructive optical interference by transmitting (6-17%) and simultaneously phase-shifting 180 degrees imaging radiation through the mask. In this paper we describe a systematic approach for designing wavelength tunable (248nm to 157 nm) attPSMs with SiN/TiN multilayers. We grew these multilayers by dual ion beam deposition (IBD) because it is potentially a cleaner process than magnetron sputtering. Compared to SiN/TiN multilayers grown by magnetron sputtering, IBD produced films with smaller surface roughness (AFM), less chemical contamination (XPS), and flatter interfaces (XRD, TEM). However, IBD films had higher stress, which can cause distortion of the mask and consequent image placement errors. We have therefore investigated strategies, which will also be discussed, to reduce stress in ion beam sputtered SiN/TiN multilayers.
3:40 PM		TF+NS+SE+VST-MoA-6 Gold Nanoparticle Films via Inert Gas Deposition: Biased Percolation and Current Induced Organization During and after Deposition L.B. Kish, P. Chaoguang, J. Ederth (Uppsala University, Sweden); W.H. Marlow (Texas A&M University); C.G. Granqvist (Uppsala University, Sweden) Gold nanoparticle films made by inert gas deposition have been attracting attention due to their super hardness and thermal stability, which make the films promising objects for future microelectronics applications. The exact origin of the superior proper ties is unknown and to learn the conditions for optimal properties, strong efforts have been made. The published investigations have been made after the films were deposited. This talk reports a different way of study: measuring the electrical conductivit y during deposition. During the measurement, various electrical fields have been applied in order to test the possible influence of the measuring current on the film formation. The time dependence of the conductivity showed various rich patterns including local maximums/minimums. The exact interpretation of the whole process is yet to be make, however, it is possible to make a phenomenological picture of the origin of the observed current-induced-organization phenomena, which include elements of: - Biased percolation: conductor-insulator transition; - Biased percolation: bad conductor - good conductor transition; - Annealing; - Sintering; - Electromigration. A possible technological application of the observed phenomena is the fabrication of nanoparticle films with controlled disorder, such as, fine tuning of chemical sensors.
4:20 PM		TF+NS+SE+VST-MoA-8 Deposition of Metallic Nanoclusters by Galvanic Displacement L. Magagnin (Politecnico di Milano, Italy); C. Carraro, R. Maboudian (University of California at Berkeley) Wet processes for the deposition of metallic films on silicon from fluoride containing solution are currently under investigation,^1,2 for applications in microelectronics and in micromechanical systems technology. This work presents a novel method for depositing nanostructured films of noble and platinum-group metals by galvanic displacement from water-in-oil microemulsions. One possible application of this process is coating of the interior walls of microchemical reactors³ for enhanced catalytic activity. The water-in-oil system investigated comprises an organic phase (n-heptane), a surfactant (AOT), and an aqueous solution of hydrofluoric acid and metallic ions. Metallic nanoclusters are deposited by galvanic displacement at the silicon substrate in contact with the fluoride containing water droplets. Nanoclusters with controlled size and distribution are obtained on silicon by regulating the micellar radius and deposition time. Scanning probe microscopy is employed to characterize the deposited films. Microscopic observations are correlated with X-ray diffraction and SEM/EDS analyses to investigate the nucleation and growth of the nanoclusters. ¹M.K. Lee, J.J. Wang, H.D. Wang, J. Electrochem. Soc. 144, 5 (1997): p. 1777. ²L. Magagnin, R. Maboudian, C. Carraro, Electrochemical and Solid-State Letters 4, 1 (2001): p. C5. ³K.F. Jensen, "The impact of MEMS on the chemical and pharmaceutical industries", Solid-State Sensor and Actuator Workshop, Hilton Head Island, South Caroline, June 4-8 (2000): p. 105.
4:40 PM		TF+NS+SE+VST-MoA-9 Cross-Linked Nano-Onions of Carbon Nitride in Thin Solid Films L. Hultman, S. Stafstrom, Zs. Czigany, J. Neidhardt (Linköping University, Sweden); N. Hellgren (University of Illinois at Urbana-Champaign); I.F. Brunell (Linköping University, Sweden); K. Suenaga (Meijo University, Japan); C. Colliex (Universite Paris-Sud, France) We report on cross-linked carbon nitride nano-onions forming thin solid films by reactive unbalanced magnetron sputtering of graphite in an argon-nitrogen discharge. The onion shells, which contain up to 20 at% N, nucleate and grow atom-by-atom on substrates at temperatures as low as 200 °C. Nanoindentation studies reveals a highly resilient material that is relevant for wear-protective applications. Total energy calculations show the relative stability of C_60-2nN_2n aza-fullerenes and suggests the existence of a novel C₄₈N₁₂ molecule with the unusual S₆ point group.