In microchips, wires usually lie flat on the surface, like rails on the ground. But sometimes one wire needs to leap over another without touching it. For that, engineers build air bridges — thin metal arches suspended above the chip.

Previously, such a bridge was assembled in several stages: deposit a layer, expose it, etch it, repeat. Each stage is a chance to mess something up. The new work shows that a single pass of the electron beam suffices. The beam draws the entire bridge at once, and then the wafer is gently heated, and the metal bends itself into a smooth arc, like a sheet of paper curling over a flame.

They tested it on quantum chips: the bridges don't interfere with the signal, but they do shield it from unwanted noise. The time during which a quantum bit retains its phase grew by a factor of two and a half. That means quantum computers will be able to compute longer without errors.

So one of the most finicky steps in chip fabrication has turned into a simple print job. Fewer steps mean less waste and cheaper future devices.