Papers by Author: Hisahiro Inoue

Abstract: Authors tried to construct multimedia base support system of the manufacturing process with use of the knowledge base and the inference engine on the www server. This knowledge database systematized the knowledge which was obtained from the document and the skilled engineer as much as possible by using a knowledge engineering technique. However, it is difficult for beginner to find the best processing condition under the condition of the material, the machine and the tool on grinding operation by using the conventional database. Especially, when they encountered the manufacturing condition which is not built into the conventional data base, the past optimum conditions cannot be obtained from the expert system. The best method of obtaining the optimum conditions as the solution of this problem is to execute some experiments for this new case. This research proposed the system, which presented a minimum combination of the multi factor experiments for the best manufacturing condition search by using the Taguchi method. We were able to obtain the best condition to use the proposed robust engineering by only 18 times.

Abstract: The mechanical properties of polymers are strongly influenced by meso-scale structure such as entanglement, orientation, folded chain, etc. However, the relationship between the meso-scale structure and macro-scale mechanical properties of polymers has not been clarified. In this paper, network models of polymer chains are introduced to simulate the meso-scale interactions. From the FEM analysis of this model, the effects of interactions on macro-scale mechanical properties are investigated.

Abstract: The volume-averaged hydrostatic parts of thermo-mechanical stresses in the metal interconnect line determined by XRD method and finite element method are compared with each other. Two typical shapes of passivated Al-0.5%Cu thin film with SiN or FOx(Flowable Oxide) are selected for this study. For the numerical calculation, the stress concentration effect around the edge of Al-Cu thin film and elastic-plastic behavior of the film following its hardening rule are considered. For the stress obtained by XRD, the experimental results of Park and Jeon[Microelectron. Eng., 69 (2003) p.26] are introduced. A good agreement is found between the volume-averaged hydrostatic stresses obtained from each method.

Abstract: Multi-layer thin films are widely used in micro-sensor and microelectronics products. These electronic devices contain several metal or polymer thin films and reliability of these systems is strongly dependent on the interfacial adhesion of these thin films. Due to the thermal stress, residual stress or elastic mismatch, the delamination between layers sometimes occurs. Therefore, it is important to evaluate the interfacial strength precisely. Peel tests are simple way to estimate an interfacial strength and, in fact, widely used in industrial field. Recently, a new simple but functional device for peel tests has developed in our group. This test method is called 'Multi-stages peel test'. There are two features in this device. At first, peeling tips can be observed continually and it becomes easy to measure a peeling angle. Second is that the peeling angle can be varied by attaching dead weights on the specimen. This dead weight works as a shear force at the peeling tip and the peeling angle can be changed variously. Therefore, the fracture tests under various phase angles are possible. In this paper, Multi-stages peel test is applied to the evaluation of interface strength of multi-layer thin films that are composed of Cu, Cr, PI and Si layers. By considering the energy balance during the peel test, the interfacial strength independent of the thickness can be obtained.

Abstract: Layered structures, especially thin film/coating substrate system play important roles in micro-electro-mechanical system (MEMS) and microelectronics packages. Many surface acoustic wave (SAW) devices/sensors adopt the layered structures to achieve high performance that with a piezoelectric layer deposited on the substrate. Recently, much work has been carried out concerning the propagation behavior of surface waves in piezoelectric layered structures, in which the piezoelectric layers are bonded perfectly with the substrate materials. Actually, due to the thermal mismatch, the unavoidable initial stress in the piezoelectric layer and the brittleness nature of piezoelectric ceramics, imperfections exist in the interfaces of these layered structures. Due to the penetration properties of surface waves, the imperfect interfaces may influence the propagation behavior of surface waves. Up to now, little attention has been paid to the propagation behavior of surface waves in layered piezoelectric structures that the imperfect interfaces are taken into account. The propagation behavior of Love waves in a piezoelectric layered structure with imperfect interface is taken into account. Solutions of the mechanical displacement and electrical potential function are obtained for the piezoelectric layer and substrate, respectively, by solving the coupled electromechanical field equations. Effect of imperfect interface on the phase velocity of Love wave propagation is discussed in detail. Results obtained indicate that imperfect interface can greatly influence the propagation of Love waves under some certain conditions. The potential application of these results in the field of mechanical behavior of materials is also shown.