EUV lithography

Extreme ultraviolet lithography patterns a wafer using light at roughly 13.5 nanometres, generated by striking tin droplets with a high-power laser and steered entirely by mirrors, because no material transmits at that wavelength. The whole optical path runs in vacuum. It is the enabling step for the most advanced process nodes, and there is no substitute that reaches the same feature sizes without multi-patterning penalties in cost and cycle time.

Its significance for supply is structural rather than technical. The systems are built by a single supplier, each one is assembled from subsystems with their own concentrated supplier bases, and annual output is counted in tens of units. That makes the entire leading edge of the semiconductor industry dependent on a production line whose throughput is public, slow to change, and effectively a sole source.

It is also the most heavily controlled equipment class in the industry. Shipment of these systems is subject to export control regimes that change with policy rather than with technology, which means a capacity forecast for a given region can be invalidated by a rule change rather than by anything happening in a factory.