FUJI ELECTRIC JOURNAL 2002 Vol.75-No.9

Analysis and Evaluation Technology

Fuji Electric's Efforts in Analysis and Evaluation Technology
Megumi Nagano, Hideaki Matsuyama, Masayoshi Sakata
This paper describes analysis techniques such as transmission electron microscopy, high brilliance synchrotron radiation (SPring-8), field emission-scanning Auger electron microscopy, secondary ion mass spectrometry and scanning probe microscopy, which are capable of supporting smaller area and thinner film semiconductor devices, magnetic recording media, and such. Also described are a technique for evaluating the junction interface of power semiconductor devices, and techniques for quantitatively predicting the temperature distribution within a device, the corresponding thermal stress, and thermal deformation, and for simultaneously analyzing and simulating the coupled heat, stress and deformation. Additionally, the prospects for micro-analysis and the analysis of material property and junction interface micro-phenomena are discussed.

Characterization of Silicon Trench Transformation
Hitoshi Kuribayashi, Reiko Hiruta
In recent years, there has been considerable interest in the fabrication of three-dimensional devices on a silicon substrate. The trench gate device, formed with a gate in the sidewall of a trench, is a typical such device and has a special characteristic of low on-resistance. To enhance the characteristics and reliability of trench gate devices, we studied the effect of using high-temperature hydrogen annealing to improve the trench structure. Macro-transformation of the trench and micro-irregularities of the sidewall were analyzed and evaluated, and the occurrence of deformation due to surface diffusion and the value of the diffusion constant were identified. Additionally, it was confirmed that the sidewall is flat, even on the atomic level.

Analyses of Materials such as Magnetic Recording Media using the Synchrotron Radiation of SPring-8
Michio Ohsawa, Ryohei Tanuma
Fuji Electric has been analyzing materials using the industrial consortium beamlines of SPring-8, the largest synchrotron radiation facility in the world. Crystallographic structures of HDD-use magnetic recording media fabricated with a non-heating process and having an Ru intermediate layer were studied by in-plane X-ray diffraction that utilizes high brilliance synchrotron radiation. It was verified that the Ru intermediate layer plays an important role in controlling the crystalline orientation of the magnetic layer. In addition, there are ongoing efforts to study the analysis of fuel cell catalysts, analysis of impurities doped in ferroelectric films, and strain analysis of Si.

Improvement of analysis technology for Secondary Ion Mass Spectrometry
Yuko Ueki, Takahiko Maeda
The large dynamic range and excellent depth resolution of secondary ion mass spectrometry has enabled this technique to be used in a wide range of fields for the analysis of metal, organic materials, including the analysis of small amounts of impurities in semiconductor devices. However, more sophisticated analysis technology has come to be required as semiconductor devices have become more densely integrated and smaller in size. This paper discusses the increased measuring accuracy enabled by an improved sample holder, enhanced depth resolution capability enabled by measurement from the underside of a polished sample, and the round-robin study conducted as a collaborative effort by Japanese industrial and academic users.

Technology and Analysis of Plastic Packaging Material for Semiconductor Devices
Yuji Ichimura, Hideaki Ito, Osamu Ishiwata
Semiconductor devices are commonly encapsulated in epoxy resin. Residual deformation and warpage occur in this resin encapsulation due to differences in the physical properties of structural materials, and consequently the encapsulation becomes susceptible to cracks, peeling, etc. The glass transition temperature of epoxy resin is an important factor to consider for optimal curing conditions. Additionally, warpage of the heat dissipating substrate is an important physical property for purposes of control. This paper discusses the development of a high precision technique for analyzing glass transition temperature and presents a technique for reducing warpage in an aluminum heat dissipating substrate, which has been targeted for use with the fillers and promoters that form the encapsulating resin.

Surface and Interface Analysis for Micro-machining and Anodic Bonding of Inorganic Materials
Tomoaki Goto, Hideaki Katakura, Kunio Shiokawa
This paper outlines surface and interface analysis techniques for the micro-machining and anodic bonding of inorganic materials. The crystalline structure of the ground face of a silicon wafer was evaluated and the mechanism by which processing force causes deformation was identified. Low stress grinding technology has been developed in order to optimize this process. The mechanism by which silicon forms an anodic bond with ceramic sputtered glass film is also identified through analysis of the ceramic-glass film interface, and the importance of controlling the migration of Na ions was verified. Additionally, anodic bonding between different materials was achieved by optimizing the bonding conditions.

Soldering Mechanism and Analysis Technique
Hirohiko Watanabe, Masayoshi Shimoda, Kimihisa Kaneko
The soldering of electronic equipment by heating flux and a tin alloy is an inexpensive and simple method of bonding. However, with this extremely simple method of soldering, solder defects are still a major cause of degraded product reliability. As an example of Fuji Electric's efforts to eradicate solder defects, and in addition to the statistical methods that have been used so far, this paper presents Fuji's efforts to identify the physical properties of solder and to understand the soldering mechanism. An example analysis is presented.

Smell and Taste Analysis and Evaluation Technology for Vending Machines
Katsuhiro Uchida, Mutsumi Nagata, Seigo Nishiwaki
Beverage vending machines that are capable of supplying beverages to users while preserving the original aroma and flavor of the beverages are in demand. A beverage vending machine must not impart any flavor or aroma that may be disagreeable to the user. Such disagreeable flavors or aromas are thought to be caused by trace constituents that volatize or elute from the component materials of the vending machine. In order to provide a hygienic vending machine that sells good-tasting beverages, sensitive and highly reliable smell and taste analysis and evaluation technology is essential. This paper introduces smell and taste analysis and evaluation technology that incorporates sensory evaluation and instrumental analysis.

Distribution Analysis of Polymer Electrolyte Fuel Cell
Yoshiaki Enami
A steady state, two-dimensional model of a polymer electrolyte fuel cell is described. The model is based on empirical data of currentvoltage characteristics and water transport measured with a 5cm2 cell. It is found that the model can provide accurate results since the calculated distributions were in close agreement with the experimental results over a wide range of gas utilization. The effect of gas permeation through a gas-diffusion layer is also investigated. By employing the gas-diffusion layer with highest permeability, the flow rate imbalance can be increased by 20% or more.

Simulation Technology for Reader/Writer of Contactless IC Cards
Tatsuyuki Shikura, Masuo Murakami, Shiro Kondo
Contactless IC cards are able to exchange data without establishing an electrical connection by means of metal pins or the like. Previously, Fuji Electric has developed several types of Reader/Writer (R/W) devices for Sony's "FeliCa" contactless IC cards. To accommodate new types of IC cards and the expanded range of applications in which R/W devices are embedded, Fuji Electric has developed simulation technology for analyzing R/W characteristics. This paper describes example results of the simulation of a R/W device consisting of a three-dimensional antenna and a radio-frequency unit.

Analysis Technology for Electrical and Mechanical Dynamics of Power Electronics Equipment
Yasushi Matsumoto, Akihide Mashimo, Ikuya Sato
Power electronics equipment is utilized in various fields such as in power supplies and motor-driven applications. In order to develop a diversity of models for various applications, each having different capacities, it is essential to fully utilize simulation technology to achieve miniaturization, lower cost, and enhanced performance. This paper describes design-stage analysis technology for computer simulation of the electrical dynamics of electrical circuits and for real-time simulation of the mechanical dynamics of motor-driven applications.

Dynamic Simulation of Magnetic Contactors with AC Solenoids
Masayoshi Wada, Hiroshi Yoshimoto, Yujiro Kitaide
This paper presents a dynamic simulator for analyzing various behaviors of electromagnetic contactors with AC solenoids. This simulator is capable of analyzing the dynamic motion of a contactor much more quickly than conventional modeling that use the finite element method (FEM) or other techniques. So that the contactor model may be computed quickly, the entire contactor, including electromagnetic circuitry and mechanical motion in response to shocks and collisions, is described by differential equations. These equations are solved simultaneously by the Runge-Kutta method. This quick analysis allows designers to investigate the effect on the electromagnetic contactor when various parameters such as solenoid dimensions, power voltage and frequency, mass and inertia of mechanical parts, etc., are changed.

Prolongation and Estimation of Longevity of Successful On-load Cycle Operation of Low-voltage Switchgears
Katsuro Shiozaki, Yutaka Kawaragi, Hidekazu Miyazawa
The prolongation of successful on-load cycle operation of low-voltage switchgear is important for the development of new products that meet global standards and are environmentally safe. Research related to longevity prolongation has focused mainly on analysis of circuit-breaking phenomena. Fuji Electric has achieved good results by evaluating and analyzing the phenomena associated with both circuit-making and circuit-breaking operations. This paper describes technology for reducing contact bounce time, material for achieving high-performance contacts, and a method for electrically estimating the longevity of successful on-load cycle operation as examples of efforts to establish essential technology. An overview of recent equipment for electrically evaluating longevity is also presented.

Analysis and Evaluation Technology for Large-capacity Air-cooled Turbine Generators
Makoto Kimura, Masahiro Hoshi
While conducting research and development for a 126 MVA proto-type turbine generator, Fuji Electric realized dramatic advances in techniques for the analysis and evaluation of electromagnetic fields, air-cooling and structural strength. Through applying these techniques, a line-up of air-cooled turbines ranging up to 300 MVA have been developed. The development of large-capacity air-cooled turbine generators is confronted with the challenges of improving the air-cooling performance and achieving the necessary structural strength of a long rotor. This paper describes design-stage analysis and evaluation techniques for the air-cooling and structural strength of a large-capacity air-cooled turbine generator.

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