ColumnThoughts On Micromachines
Kazuhiro Hane, Professor, Department of Nanomechanics,Graduate School of Mechanical Engineering, Tohoku University
Some twenty years ago after completing mydoctoral course, I was accepted to teach in a newdepartment at the university. The new Department ofMechatronics was established in response todevelopments in mechatronics in the industrial world.
The classes were very lively, as the students wereattracted to the new field, and there was much
expectation placed on the young instructors in thenew department. Although micromachines (MEMS)
was one of the fields that produced heightened
expectations, we organized the course with a broader
concept: an integrated mechanical engineering course.
One goal of the course was to develop semiconductor
micromachining into a mechanical field. News from
America such as the trial production of achromatography system on a silicon wafer drew muchattention. With this background, dreams and hopes
for micromachines began to grow.
Integrated circuits produced in semiconductors
were also developing rapidly in Japan during this time.
The level of integration of IC's increased by tens ofpercentage points each year, and as a result theperformance of computers increased dramatically.
While more recent increases in memory capacity from,say, 1G to 2G may seem to the ordinary user as merely
an increase in an already sufficient memory capacity,
back when people were trying to get by with very
limited memory, an increase in 1M to 2M wasextremely beneficial and a remarkable development in
the semiconductor industry. However, the Japaneseindustry that has shown steady development ismechatronics. This field, which merges machines andelectronic systems, demonstrates the superior abilityof the Japanese in manufacturing, as is represented by
the automobile and automated production equipment.
If the equipment and technology could be established,mechatronics, which requires many variations andmerged technologies, was expected to be more suited
to Japan's capacity for manufacturing than integrated
circuits, which are easy to mass produce. Japan is also
good at making mechanical and electronic goods
smaller and has shown its superiority to the rest of theworld in manufacturing compact recorders,
timepieces, and camera systems. However, I think thatJapan should place more emphasis on micromachines,
which can be considered an extension ofmechatronics.
Processing techniques for micromachines haveadvanced considerably in the last twenty years.
Flexibility in the 3-dimensional processing of siliconusing developments in DeepRIE has improved morethan in anisotropic etching of crystals. However,
DeepRIE is only capable of about 2.5 dimensions, notthe unrestricted 3-dimensional processing that ispossible in macromachining. It is expected that 3dimensional processing will be developed with a higher
degree of freedom in the future. As these processing
techniques improve, numerous sensors andmicrosystems are being proposed and experimentallyproduced. Since many problematic areas inprocessing must be resolved to complete such trial
manufacturing, once a proposal for trial manufacturing
is agreed upon, researchers focus on specificproblems. Although researchers always like toconcentrate on detailed problems, I believe that abroader perspective will be required when developing
micromachines in the future.
In the near future, Japan and the world will befaced with such problems as environmental issues, thegrowing population, and the food shortage. Japan is
only about forty percent self-sufficient in food, with
about one-fourth of its entire food supply going towaste. Therefore, it is necessary to construct systems
for using resources and distributing food that are notwasteful. What will our society be like twenty years
from now? Striving for profits in the industrial world isthe fate of humankind, but, while it is important toproduce products that are at least somewhat efficient,shouldn't ten or twenty percent of our efforts beaimed at some aspect that can contribute to problems
facing all of Japan twenty years from now? Sinceproblems facing the environment are pervasive, theissue is somewhat diluted, as most individuals today
don't feel these problems affect them. To understandthese types of widespread problems, I think it isnecessary to study sensing and mobility over a large
area. Networks continue to expand in towns andthroughout the world, and I believe network
technology will be an indispensable means forunderstanding large areas. By incorporating
microsensors in networks, we may be able to placethese pervasive problems of distribution and theenvironment in a context that we can understand. It
seems that micro-problems in science can be resolved
by tackling them analytically. However, I think it isnecessary to develop new techniques for solving
macro-problems.
Perhaps you remember the catch phrase "Can you
work 24 hours a day?" If the trend of today's fastpaced society continues, such a scenario may not bealtogether out of the question twenty years from now.
I think we must strike a new course toward anaffluence different from the materialistic, hurriedsociety of today. It is my hope that MEMS, atechnology indispensable for providing input andoutput between various sensors and computer
networks, can contribute to the solution of these
problems.

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