What lithography does
Lithography transfers mask patterns onto a photoresist-coated wafer through projection optics. DUV lithography supported many generations of scaling. EUV uses 13.5 nm light to improve resolution and reduce the need for repeated multi-patterning on the tightest layers. ASML EUV systems are a critical tool class for leading-edge logic manufacturing.
The hard part is not only resolution
Advanced lithography must control critical dimension, overlay, depth of focus, resist chemistry, stochastic defects, and mask error. EUV photons have high energy, while the source and reflective optics are extremely complex. Stochastic effects can turn contacts, narrow lines, and edge roughness into yield risks.
Why GPUs care
A large GPU logic die uses many critical lithography layers. Overlay error can affect transistor behavior, resistance, capacitance, and interconnect reliability. Lithography also matters in advanced packaging, where RDL, interposer routing, and micro-bump patterns determine chip-to-chip connectivity.