Japan“s Toto Ltd. has developed a new type of corrosion-resistant glass for the observation windows in semiconductor manufacturing equipment.
The new glass is made by coating quartz with a thin laye…
Japan“s Toto Ltd. has developed a new type of corrosion-resistant glass for the observation windows in semiconductor manufacturing equipment. The new glass is made by coating quartz with a thin layer of yttria, a transparent ceramic material. Viewing windows made from the new glass can resist the corrosive plasmas used for circuit etching 50 times longer than normal quartz glass and five times longer than sapphire. Greater durability means fewer replacements, and less equipment down time. As the coated glass releases few impurities as it corrodes, there is less chance of defects arising during the chip-making process, and the better yields mean lower costs. Toto makes the glass by blasting nanograins of yttria against quartz glass. The grains, which measure several hundred nanometers in diameter, break apart into smaller granules measuring several tens of nanometers in size, which accumulate on the surface of the glass as an even coating with a thickness of 2-10 microns. Toto plans to ship samples of the new glass material over the next 12 months. The material will be more expensive than quartz glass, but cheaper than sapphire.