Ionized cluster beam (ICB) deposition of TiN barrier metal for ultra large scale integration (ULSI) applications has been developed. The bottom coverage of reactive-ICB was 54% and 24% for 4.0 and 6.7 aspect ratio contacts (2.0 µm in depth and 0.5 µm amd 0.3 µm in diameter). Therefore the ICB has high potential to fill sub-half-micron contact holes with high aspect ratios. The resistivity of Ti and TiN deposited by ICB and reactive-ICB is found to be 50 µQ cm and 180 µQ cm, respectively, at a substrate temperature of 300°C. The ICB can also provide low contact resistance and good adhesion by low energy ion bombardment during film growth. The beam simulation explains the bottom coverage of ICB as well as conventional sputtering. Using the larger number of atoms in a cluster, the bottom coverage becomes almost 100% due to the long mean free path of the deposited cluster in gas and its heavy mass.

Low-energy ion bombardment during film growth can significantly modify film properties. The advantages of using the ionized cluster beam (ICB) deposition techniques include reduced damage and high deposition rates at low temperature. The long-lived ICB source without the electron extractor is designed for an in-house experiment of aluminum deposition. In the initial experiment for aluminum metallization, low resistivity and highiy preferrentially oriented Al films were obtained at acceleration voltages from 0.5 to 1.0 kV and at room temperature. This ICB source provides uniform ion current profiles within ±10% at deposition rates up to 0.1 µm/min over a 254 mm-diam substrate. It has been operated for more than 300 µm-thick Al film deposition without any maintenance.

Stress corrosion cracking (SCC) was investigated by spectral analysis of corrosion potential signals. Caustic cracking of carbon steel (S10C) and SCC of stainless steel (SUS304) in various chloride solutions were studied. The marked change of the power spectral density (PSD) in the frequency domain was observed in the vicinity of 5mHz for caustic cracking of carbon steel and in the frequency range from 10 to 100mHz for SCC of stainless steel. It was also observed that the corrosion potential signal in 20%NaCl+1%Na2Cr2O7 solution was bigger than in 42%MgCl2 solution or 60%CaCl2 solution for SCC of Stainless steel. By comparing PSD with the changes of elongation and corrosion potential, the following conclusion was obtained: the increase of PSD might be related to the breakdown of passive film and the generation of cracks for caustic cracking of cabon steel, while its increase might be attributed to the localized change in the passive film for SCC of stainless steel.Key words: Stress corrosion cracking, Caustic cracking, Spectral analysis, Power spectral density Table I. Chemical composition (wt %) and mechanical properties of S10C steel. Chemical composition (wt %).

The theory for acoustic gravity modons is generalized. As a result, the equations governing the whole internal gravity wave branch are deduced. The threshold modon velocity is also found.

High damage threshold coating for high energy KrF excimer laser has been developed by the multiple ion beam deposition system, which contains a couple of the ionized cluster beam (ICB) sources and the ionized gas beam source. The damage threshold of low refractive SiO2, high refractive A12O3 and SiO2/A12O3 multilayer coatings is found to be more than 105 shots at 8J/cm2 laser energy. Oxidation is enhanced by ion bombardment during the film growth.The refractive indices of SiO2 and A1203 films were 1.46 and 1.62 at the ion current density of 0.8μA/cm2. The film density of SiOx approaches to the bulk SiO2 of 2.3Og/cm3 with increasing ion current density. The stress-free SiO2 film can be obtained at the ion current density of around 0.5 μA/cm2.