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We newly developed a metal-bonded Langevin transducer using LiNbO3 in order to realize a practical high-power LiNbO3 Langevin transducer. It utilizes metal bonding with a lead-free solder as an assembly method for a Langevin transducer, instead of a bolt as used in a conventional bolt-clamped Langevin transducer. The newly developed metal-bonded LiNbO3 Langevin transducer achieved a high vibration velocity of over 1.5 m/s and stable operation. Because of rigid metal bonding, it does not show nonlinear phenomena such as a jump phenomenon and/or a resonant frequency shift.

TEM(Transmission Electron Microscope) observation for the device failure analysis is strongly demanded to achieve high production yield and high reliability of VLSI memories with a high bit density and a. complicadd structure. We have developed a new XTEM(cross sectional TEM) sample preparation technique using FIB(Focused Ion Beam) marking [1], which makes it possible to observe a specified point on VLSI chips. Applying this technique to the analysis of retention-time-failure bits in a DRAM with trench cells, it was found that the oxygen precipitate exists near the trench bottom of the failure bit with excess node-to-substrate leakage current. After a, retention failure bit on a chip is specified with IC tester, V-shape and I-shape patterns are grooved by using the FIB, as shown in Fig.l. The Vshape pattern is used for a position monitoring during the sample thinning, while the I-shape pattern defines the location of the failure bit cell after th.e sample preparation i s completed. Monitoring the specified cell by SlM(Secondary Ion Microscope) image in FIB machine, V and I patterns were formed in the positions 2-3pm apart from the failure cell. The cell-to-mark distance of 2-3pm is necessary to avoid FIB induced damages.

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