Asahi Glass’s synthetic quartz, essential for manufacturing sophisticated semiconductors

Semiconductors are indispensable for modern life. In order to manufacture semiconductors where an enormous amount of circuits are recorded in an extremely tiny area, it is necessary to have a device with a laser beam that is controlled precisely on a nanometer scale for exposure, like image printing on developing paper in photography. Asahi Glass’s synthetic quartz is used for lenses that are indispensable for the device.

100% pure high-quality glass penetrating light sources on a nanometer scale

In today’s semiconductor manufacturing, a very short laser source of 193 nanometers is being used. Because of this, a projection lens used for an ArF excimer laser, which is an exposure lens system for manufacturing semiconductors, needs to offer high purity, transmittance, and optical and chemical durability required for that precision. The component fraction of silica dioxide (SiO2) that is used as a material for ordinary glass is approximately 70%, but "synthetic quartz" used for exposure lens systems for integrated circuit manufacturing needs to be highly pure with nearly 100% of SiO2. In addition, the deformation of glass should be eliminated at the manufacturing stage so that the glass will not cause the refraction of light. It is essential to manufacture extremely highly transmittable synthetic quartz that can be used for stable transmission through a laser source with a wavelength of 193 nanometers, which is mainly used now. In addition, high durability must also be realized in order to control deterioration and damage as much as possible because of frequent transmission through a laser source.

Asahi Glass’s globally recognized technology

Asahi Glass manufactures highly-pure, high-quality synthetic quartz materials for lenses for integrated circuit manufacturing based on its long-established expertise, and advanced technological research and development on fine glass, chemicals and ceramics.
It can be said that Asahi Glass’s manufacturing process is close to that of a chemical plant rather than that of a glass plant. It generally takes several months to complete the manufacture of a single piece of highly-pure synthetic quartz. The raw materials are made to react at high temperature, and the temperature is lowered slowly for several months so that the materials will not be deformed by the abrupt change of the temperature. Even after the completion, we spend several days for quality inspections to ensure that the transmittance, durability and refractive indices of laser sources meet the specified values.
Asahi Glass manufactures synthetic quartz through strict quality control like this. There are only a few companies that are capable of manufacturing lens materials for ArF excimer lasers in full response to the needs of the manufacturers of exposure lens systems for integrated circuit manufacturing. Asahi Glass’s technology is highly valued worldwide, and holds the top market share.

Development capability in response to the market needs, which continue to evolve in more sophisticated ways

There are various electronics using semiconductors on the market. A trend for miniaturization and high performance is the need of the market, and technological changes have been remarkable. With the evolution of semiconductor manufacturing technology itself, research and development on higher-resolution, higher-quality lens materials are now also understandably underway.
Because it takes several months to manufacture materials for a piece of lens, the semiconductor market a few years ahead must be predicted in order to manufacture glass, and new technology must be developed. Asahi Glass has also been actively working on the development of materials for an EUV nanoexposer with a wavelength of 13 nanometers, the next generation of ArF excimer lasers.

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