The upcoming book The Big Thirst by Charles Fishman discusses the ultra-pure water used in semiconductor manufacturing. It’s so pure and free of dissolved minerals that drinking it is dangerous. Apparently it will leech these vital minerals from your body to a dangerous degree. (This might be some hype, because it doesn’t say how much of the water you’d need to drink–people have been accidentally killing themselves for years by overconsuming normal water in misguided attempts to pass drug tests.)
The water must have nothing in it except water molecules–not only no specks of dirt or random ions, no salts or minerals, it can’t have any particles of any kind, not even minuscule parts of cells or viruses.
And so every microchip factory has a smaller factory inside that manufactures ultra-pure water. The ordinary person thinks of reverse-osmosis as taking “everything” out of water. RO is the process you use to turn ocean water into crystalline drinking water. And in human terms, RO does take most everything out of the water.
But for semiconductors, RO water isn’t even close. Ultra-pure water requires 12 filtration steps beyond RO. (For those of a technical bent, the final filter in making UPW has pores that are 20 nanometers wide. At the IBM semiconductor plant I visited, they send the 20 nm filters out to be inspected by a private company, using a scanning electron microscope. They want that company to find filters with nothing in them.)
via The Dangerously Clean Water Used To Make Your iPhone | Fast Company.
