[VIEWPOINT][Nanotechnology Will Ensure the FutureSeeing his grandfather carve an impressive bear out of a piece of wood, the child asked, "Grandfather, how do you carve such a wonderful bear?" At that, the old man replied, "That is quite simple. Just cut out the part, which is not the bear."
The traditional technique for manufacturing semiconductors is lithography: Leaving the part that is the circuit and carving off the rest on a piece of silicon. This technique is employed by Samsung Electronics, number one manufacturer of semiconductors, in producing 4Gb DRAM, which they had developed for the first time in the world. The width of the circuit line of DRAM is 0.1 micron, which is approximately a thousandth of the width of a strand of hair, and is in the level of the thinnest, ever produced. In order to produce more proficient semiconductors the circuit line should become thinner, but under lithography technique, it is impossible to improve this fundamentally. This is because lasers are used to shave off the unnecessary part. As the circuit line becomes thinner, its wavelength gets similar with the laser carving the silicon and inevitably results in the diffraction of light, which inhibits the lithography process. Therefore, it can be said that Samsung Electronics have reached the fullest achievement in lithographic techniques. In the future, in order to reduce the width of circuit lines and enhance integration of semiconductors new manufacturing technology must be introduced.
Recently, President Kim Dae-jung had designated information electronics, biotechnology and nanotechnology as three major strategic state-initiated scientific technical sectors. Former U.S. president Bill Clinton had also emphasized the importance of nanotechnology, earlier. Why is the world making such a big fuss over nanotechnology? Millimeter is a thousandth of a meter and micrometer is a thousandth of a millimeter. Nanometer is a thousandth of a micrometer. Therefore a nanometer is about a billionth of the height of a kindergartner who stands one meter tall. When the semiconductor structures get smaller the amount of information held will rise and thus increases the speed of the information manageable.
But the length of nanometer is a line of a mere ten atoms. The nano scale structures with the width of several tens of atoms are impossible to build under the method of lithography. The only way to build this structure is to arrange one atom after another, precisely. It cannot be achieved by simply arraying the atoms. The atoms in need should be linked together in a specific order. It's like trying to make things out of the LEGO blocks. Fortunately, for last 200 years chemistry had developed different techniques of bonding different chemical compounds. Arranging atoms is the specialty of chemistry.
Unlike from the scale of millimeter and microns, in the scale of nano, principles of quantitative mechanics are applied, which is totally different from the macroscopic world. Therefore, the role of physics is critical in the science of nanotechnology. It is because the different and useful functions, which vary from the kind of atom and structure, should be clarified. Apart from the manufacture of semiconductors, the application of the nanotechnology is limitless: It could be utilized in medical and biotechnology sector. Contribu-tion from material engineering, electronic engineering and mechanical engineering is needed to apply nano scale structures in producing practical components and devices. In this sense, nanotechnology is a promising field of the 21st century, which can create tremendous amount of national wealth from the interdisciplinary studies including fundamental science such as chemistry and physics and different fields of engineering. Perhaps in ten years semiconductors manufactured by lithography technique may disappear. If Korea doesn't invest efficiently in nanotechnology, the days of its prominent semiconductor industry may be numbered.
The writer is the professor of chemistry at Seoul National University.
by Kim Hie-joon