When every atom counts

Today's chips are marvels of mass production. Tens of thousands of silicon wafers can move through a single fab in a month, each one carted from tool to tool, blasted by heat, bombarded by ions, immersed in vapor, coated with chemicals, hit with radiation, and exposed to acid. It can take months and hundreds of steps to transform a plain piece of silicon into an array of chips. But at the end of this elaborate assembly line, chipmakers finally get a pile of identical devices that perform just as their designers intended.