Worldwide R&D

Nano Coordinate Measuring Machine and Nanoprobe
Kiyoshi Takamasu, Professor, School of Engineering, the University of Tokyo
One objective at our laboratory is to develop a threedimensional measuring instrument called a Nano CMM (NanoCoordinate Measuring Machine) for measuring objects threedimensionally with nanometer resolution. Currently, we canmeasure the three-dimensional surface of objects with nanometer
resolution using STM and AFM. However, we are unable to truly
measure three-dimensional shapes, such as the diameter of holes
formed in the side of an object, surface direction, or related
dimensions. We believe that a device for measuring threedimensional sizes, positions, and other shapes on a nanometerorder will be an indispensable basic tool in the future
development of micromachines. The necessity for this research
was first proposed at our laboratory, after which we began
development. Recently, however, many other countries, including
Germany, Holland, and UK, have been developing instruments forthe three-dimensional measurement of objects on a nanometerorder.
Fig. 1 shows the construction of a Nano CMM. This threedimensional measuring instrument was made more compact formeasuring three-dimensional shapes and dimensions in theautomobile industry and the like. About 300 x 300 x 200 mm insize, this device has a measuring range of 10 x 10 x 10 mm and aresolution of 10 nm. The measuring device has a symmetricalconstruction with a double Vee groove guiding mechanism andemploys a position sensing method using an optical scale toachieve high stability. Fig. 2 shows a prototype of the Nano CMM.
When measuring the absolute shape and dimensions of objects on
a nanometer order, the factor causing greatest error istemperature drift. When a 100-mm length of iron rises 1 degree intemperature, 1 µm of thermal expansion occurs. This effect isdirectly reflected in the measured value. This prototype canrestrain thermal drift of about 10 nm in an environment of about
0.1 degrees, as the entire mechanism is constructed of material
having low thermal expansion and is designed to restrain theeffects of temperature.
The most problematic point in Nano CMM researchworldwide lies in the probing system. Numerous contact-type
probing systems have been used in three-dimensional measuring
devices in order to achieve stable measurements of threedimensional positions and dimensions for objects formed of avariety of materials and having a variety of surface conditions. A
contact-type Nanoprobe having two-dimensional or threedimensional sensing capacity and resolution on the nanometerorder is necessary for Nano CMM.
Fig. 3 shows the construction of a Nanoprobe and a prototype
that we developed. The object to be measured is contacted by asmall ball having a diameter of less than 0.5 mm. An optical sensor
detects the movement of the ball. By combining a contact-type
measuring instrument and optical sensor in this way, it is possible
to construct a reliable Nanoprobe capable of high resolution.

Fig. 1 Construction of a Nano CMM

Fig. 2 Prototype of the Nano CMM

Fig. 3 Construction and prototype of a Nanoprobe
As described above, development is proceeding on Nano
CMM and Nanoprobe, which will become basic tools fordeveloping future micromachines. However, various issues
remain before these devices can be put to actual use, such as theestablishment of a method for calibrating the measuring
instrument, as well as evaluations of the reliability and thedurability of the device. Our laboratory hopes to continue leading
the world in research on establishing Nano CMM.

MICROMACHINE No. 40
MICROMACHINE is published quarterly by Micromachine Center (MMC) to promote the international exchange ofinformation related to micromachines, R&D and other technical topics, and is circulated free of change. Please send
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Date of Issue : August 22, 2002

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