Site: University of Tokyo
Institute of Industrial Science
7-22-1 Roppongi Minato-ku
Tokyo 106, Japan
Date Visited: September 27, 1993
Report Author: R.S. Muller
Fumio Harashima Professor; Director General, Institute of Industrial
Felix Moesner Graduate Student, Fujita Group
Manabu Ataka Graduate Student, Fujita Group
The following comments are from an interview with Director General Fumio Harashima that preceded the team's visit to individual laboratories.
The Institute of Industrial Science (which consists of twelve institutes) is a part of the University of Tokyo. The institute was founded in 1949 as a research establishment for engineering at Japan's most prestigious university, which was established in 1877. The institute carries out only graduate teaching and research with ~350 students, ~95 faculty members, ~72 research associates, ~118 clerical staff members, and ~83 administrative staff members. The director general serves a three-year term and is generally selected from among the full professors. Professors teach one semester course in a year, and the institute typically hosts ~200 visitors. The budget for 1993 was $60 to $70 million; 40 percent of this was used for salaries. Fifty percent of the budget comes from the national government, and 50 percent comes from research contracts (industrial). All faculty at IIS-UT are tenured.
The institute is further divided into nine departments and research centers. Of special relevance to the JTEC visit is the Research Group of Excellence on Micromechatronics, which consists of the laboratories of faculty members whose work centers on MEMS. Those faculty in the research group are five IIS-UT regular professors augmented by two Toshiba Chair professors who are at IIS-UT for a year or longer. The five IIS-UT professors and the specialties of their research laboratories are:
The two Toshiba-chaired visitors are:
Graduate student Felix Moesner acted as host in Professor Fujita's absence, and took the JTEC team to Director General Harashima, then to Kawakatsu and Masuzawa laboratories before the visit to the Fujita laboratory. No professors were present.
The first visit was to the Kawakatsu laboratory, where metrology based upon scanning tunneling microscopy is being developed; the idea is to position an xy table using the lattice spacing of C atoms in a lattice for the scale of reference. In the same area, the team viewed research on a laser-guided magnetic suspension system being carried out under the supervision of Professor Hannes Bleuler (of ETH, Zurich).
In the Masuzawa laboratory, the focus was on "wire electric discharge grinding" (WEDG), which is a technique for machining microholes and microshaping to form nozzles and other shapes down to ~4 micron diameters.
The Fujita laboratory visit was notable for its total concentration on IC-based processing. Figures IIS.1 and IIS.2 show the activities and facilities. The consensus of the group visiting was that the laboratory is very crowded and has what would be considered in the United States significant safety hazards. Despite the limited facilities, Fujita's group is outstandingly productive in research.
The IIS-UT capacity to transform and reform its parts to address a broad research program is shown up positively by the Fujita-led Research Group in Micromechatronics. Both Professors Fujita and Kawakatsu provided selected answers in writing to the JTEC questionnaire on MEMS. The answers from Professor Fujita are summarized below:
Figure IIS.1. Projects in H. Fujita laboratory, 1993.
Figure IIS.2. Process facilities in H. Fujita laboratory, 1993.
Professor Kawakatsu's answers to the team questionnaire are keyed to the JTEC team's questions below. [A complete list of questions posed by the panel is included in the Yaskawa Tsukuba Research Laboratory site report, pp 225-236.]
B1. For which sensed variables and types of sensors will MEMS technology have the greatest importance? What are the key advantages of MEMS technology for these sensors?
B4. What new sensors can only be developed using MEMS technology? How does MEMS make these new sensors feasible?
In the field of scanning microscopy such as STM or AFM, the technique of probing samples with the probes in close proximity is expected to enable powerful measuring methods (e.g., differential tunneling), considered difficult in macrosystems.
B8. What are the principal problems in the use of scanning surface probes (e.g., tunneling current) as an approach to high-sensitivity sensor readout? Is this approach likely to find wide application?
As can be seen from the fact that the earlier models of atomic force microscopes using tunneling gaps for cantilever deflection detection [were] soon replaced by AFMs using other detection techniques, stability of tunneling tips and targets is not suited for built-in, on-chip sensors. However, a metal-insulator-metal structure using a suitable (if any) insulator layer may become a high sensitivity sensor with robustness against mechanical shock and contamination.
C2. Considering their importance to MEMS, in what order of importance would you place the following microactuation mechanisms: shape-memory alloys, electromagnetics, electrostatics, thermal bimorphs, piezoelectric bimorphs, piezoelectrics, electrostriction devices, [and] phase-change devices? How many of these do you expect will find commercial applications in high-volume products?
I am optimistic about the possibilities of the electromagnetic actuator. I think in some applications, it does not matter if the device for generating a field is large (e.g., a macrostator for levitation and attitude control of a microsuspended object).
F17. What are the principal barriers to the success of MEMS?
For commercial success: mass production of sensors in an easy to install package (e.g., a dual in-line package). For success in the frontiers of research, application of MEMS to fields where a macroscopic systems approach is not feasible.