Wafer silicon photolithography

Wafer silicon photolithography: a fundamental process in semiconductor chip manufacturing, used to transfer integrated circuit patterns.

About this subject

Photolithography is a critical step in the fabrication of integrated circuits (chips). A silicon wafer, a thin disc of monocrystalline silicon, is coated with a photosensitive material called photoresist. Using a mask containing the circuit design, ultraviolet light is projected onto the wafer, changing the solubility of the exposed photoresist. Unexposed areas are chemically removed, leaving a pattern that guides subsequent etching and deposition steps.

The photolithography process is repeated dozens of times per chip, each layer adding new elements (transistors, interconnects). Precision is on the order of nanometers: modern techniques like extreme ultraviolet lithography (EUV) enable transistors with dimensions below 10 nm. The semiconductor industry moves over US$ 500 billion annually, and photolithography is its heart.

Historically, photolithography evolved from offset printing techniques. Since Jack Kilby’s first integrated circuit in 1958, the resolution of lithography machines has increased dramatically. Companies such as ASML, Canon, and Nikon dominate the manufacturing of these tools, which cost hundreds of millions of dollars. A typical wafer is 300 mm in diameter and can hold thousands of identical chips.

Fun fact: the name comes from Greek “photos” (light) and “lithos” (stone), referring to engraving by light. The purity of photolithography cleanrooms (Class 1) exceeds that of an operating room, as dust particles can ruin nanoscopic patterns.

Frequently Asked Questions

What is photolithography on silicon wafers?

It is the process of transferring integrated circuit patterns onto a silicon wafer using ultraviolet light and photoresist, forming the basis of electronic chips.

Why is photolithography important in the semiconductor industry?

It enables the creation of transistors and interconnects at nanoscale, essential for miniaturization and performance of modern chips.

Which companies are main suppliers of photolithography equipment?

ASML (Netherlands), Canon and Nikon (Japan) are leaders, with ASML dominating the EUV lithography segment.