How Microchips Are Made

Microchips are built layer by layer on a wafer of the semiconductor material silicon. The layers are built by a process called photolithography involving chemicals, gases, and light.

First a layer of silicon dioxide is deposited on the surface of the silicon wafer, that layer is covered with a photosensitive chemical called a photoresist.

The photoresist is exposed to ultraviolet light shined through a pattern, which only hardens the areas exposed to the light. Gas is used to etch into the remaining soft areas. This process repeated and modified builds the component circuitry.

Conducting paths between the components are created by overlaying the chip with a thin layer of metal (aluminum). The photolithography and etching processes are used to remove the metal leaving only the conducting pathways.