How microchips are made

Grow an oxide skin

Wafers travel in sealed boxes and are heated in oxygen until a thin layer of glassy silicon dioxide forms on top. This layer insulates and protects the silicon below.

Spread on light-sensitive resist

A liquid made from resin, a light-sensitive chemical and solvent is spread across the whole wafer, then baked solid.

Draw circuits with ultraviolet

In the most advanced machines, a laser hits tin droplets about 25 micrometers wide, flying at roughly 70 meters per second, and the resulting plasma emits light at 13.5 nm. Glass and air absorb that light, so mirrors in a vacuum steer it onto the wafer.

13.5 nm light

Etch and implant

A developer washes away the exposed resist. Plasma etching then cuts the pattern into the layer below, or ion implantation embeds dopant atoms in the open areas to change how well silicon conducts.

Lay down copper wiring

Thin films of insulator and copper are deposited on top, forming the wires that connect transistors.

Repeat layer by layer

A complex chip goes through the coat, expose, etch cycle many times. At advanced nodes the whole run takes up to 15 weeks, and 11 to 13 weeks is the industry average.

11 to 15 weeks

Probe every die

Automatic test equipment touches each die on the wafer and checks that it works, so faulty chips are not built into expensive packages.

Saw and wire up

The wafer is cut into individual dies. Each good die is connected to a package with fine aluminum or gold bond wires, or flipped over onto bumps, and tested again.