Standardization Activities
This project is being implemented under a three-year planthat began in FY 2008, and the findings of the project will besubmitted to the Subcommittee on MEMS (SC 47F) of theTechnical Committee on Semiconductor Devices (TC 47) underthe International Electrotechnical Commission (IEC). Initially
we intend to submit a new proposal on electronic compasses
within the current fiscal year.

While the Micromachine Center (MMC) promotes
standardization related to MEMS technology, this article will
detail our current R&D projects.

Developing Standards for Micro-gyroscopes andElectronic Compasses
Gyroscopes are indispensable for controlling the attitude ofa device in a space by detecting fluctuations in attitude. Recent
developments for reducing the size and cost of devices while
improving performance through MEMS and other technologies
have led to a more active role for micro-gyroscopes in various
contexts of daily life.
Gyroscopes incorporated in controllers for game consoles
detect movement in the controller and adjust the image
accordingly. An image stabilizer has become a standard
feature of digital cameras and is even provided in thecameras of cell phones. This function is achieved with agyroscope that detects attitude changes in the camera andmoves the lens and image-detecting unit accordingly.
Gyroscopes having greater precision and resistance toimpacts are the key components of safety systems installedin vehicles to control the engine and brakes when detecting
impacts and changes in attitude. Even higher precision
gyroscopes have appeared in aircraft and space applications.
Now efforts are being made to replace the conventional
gyroscopes, which have good precision but are heavy andbulky.
Compasses are age-old instruments that have beencentral to navigation for ships and aircraft. A compass
detects the Earth’s magnetic field and displays the directions
north, south, east, and west. However, since geomagnetism
itself is very faint, various compensations are needed toboost the precision of the compass, resulting in a large andheavy instrument. Recent years have seen the appearance ofan electronic compass that combines a sensor element for
detecting geomagnetism with a system for analyzing andprocessing the sensor signal. With their decreasing size andcost, electronic compasses are being provided in cell phones
to configure a navigation system for pedestrians that candetect the user’s position with the Global Positioning System(GPS) and directions with the electronic compass.
Consequently, the number of practical applications for
micro-gyroscopes and electronic compasses continues togrow. The objective of our project is to standardize thespecifications and methods of measurement needed to define
the performance of these devices as sensors. This isexpected to lead to more efficient communication between
device manufacturers and users.
For micro-gyroscopes, we have established an absolute
maximum rating, recommended operating conditions, andvarious characteristics, including sensitivity, cross-axis
sensitivity, bias, output noise, frequency response, andresolution. We are also investigating methods for measuring
these properties.
Similarly, we have established an absolute maximum
rating, recommended operating conditions, andcharacteristics for electronic compasses, and are studying
methods of measuring the analog circuit characteristics andDC characteristics of these devices. Further, although it isgenerally assumed that conventional compasses are installed
in a more or less level orientation, cell phones obviously havea high degree of flexibility in how they are oriented.
Therefore, we are suggesting new ways of conceptualizing
the coordinate system of these compasses.

Developing Standards for Measuring Microscale Dimensions
MEMS applies techniques used in semiconductor
fabrication to produce three-dimensional structures. Whiledimensions and other aspects of the 3D profile are importantelements of structures, a method of measuring such profiles has
not been established. Accordingly, the goal of our project is tostandardize a suitable method of measuring dimensions andshapes of microscale structures.
MEMS devices are fabricated using the time-consuming
techniques of wet etching and deep dry etching. However,
MEMS structures inherently have a microscale profile, andtechniques have not yet been established for measuring theangle of a forward tapered or reverse tapered side wall, thedepth and width of high-aspect-ratio trench structures, and thesurface roughness resulting from etching. We are measuring
microscale structures according to a variety of techniques withthe goal of standardizing techniques for evaluating suitable
methods of measuring the dimensions and shapes of such
structures and of expressing such dimensions and shapes.
Using the standard, it is likely that designers, manufacturers,and others involved in the various stages of MEMS fabrication
can better communicate with one another. This is a three-year
project that began in FY 2009, and we will be submitting ourfindings to the SC 47F of the IEC TC 47.
Our study involves creating specimen for use as a reference
for measuring MEMS profiles, measuring these specimen
according to a variety of techniques, and comparing andevaluating the results. Specimen are produced by creating
structures having different aspect ratios (ratio of depth towidth) and spacing their gauge marks at varying distances.
Specimen are measured using an optical microscope, a laser
scanning microscope, a scanning white light interferometer, an
optical standing wave scale displacement sensor, a stylus-typecontact profilometer, and other apparatus, and the results areanalyzed through comparisons with reference measurements
obtained using a high-resolution field emission scanningelectron microscope (FE SEM). We have also included 3D
microprotrusion structures as specimen.
As we enter the second year of the project, we arecontinuing to collect and organize data obtained throughrepeated measurements in order to develop standards forcomparing and evaluating methods of measurement and forexpressing dimensions and shapes of the microscale structures.
Create 3D trench structure asa standard MEMS test piece

Establish technique for measuring
microscale dimensions

垂直走査Ex. 1 Scanning whitelight interferometer

Establish expressions
for microscale profiles

Standardized expressions
for microscale profiles
itemWidthB
AAB5ı

Tapered shape Forward/Reverse
Taper1/100Depth100ı

Step profile calculated from time difference
between A and B

Ex. 2 FE-SEM

6

Profiling of scallop-like side wall