TECHNOLOGY

Lithography principles

The basics of photolithography, the critical step in the chipmaking process

Microchips are made by building up complex patterns of transistors, layer by layer, on a silicon wafer. ASML’s lithography systems are central to that process.

A lithography (more formally known as ‘photolithography’) system is essentially a projection system. Light is projected through a blueprint of the pattern that will be printed (known as a ‘mask’ or ‘reticle’).

With the pattern encoded in the light, the system’s optics shrink and focus the pattern onto a photosensitive silicon wafer. After the pattern is printed, the system moves the wafer slightly and makes another copy on the wafer.

The science behind the chip