October 19, 2018
Many semiconductor fabricators and research labs are under increasing pressure from, of all things, vacuum. These facilities need to remove greater amounts of gas molecules and particles from their setups as new technologies and processes demand lower and lower pressures. For example, the vacuum chambers in which microchip manufacturers lay down a series of ultrathin layers of chemicals step by step—a process that must be utterly free of contaminants—operate at about one hundred-billionth of the air pressure at sea level. Some applications need pressures at least a thousand times lower than that, approaching the even more rarefied environments of the Moon and outer space.
Measuring and controlling vacuum at those levels is an exacting business in which accuracy is essential. Current technology usually relies on a device called an ion gauge. However, ion gauges require periodic recalibration and are not compatible with the new worldwide effort to base the International System of Units (SI) on fundamental, invariant constants and quantum phenomena.