EUV Scanner Architecture
EUV Scanner Architecture
ASML's EUV scanners are the most complex and expensive machines in the world:
- Source: A 25 kW CO₂ laser fires 50,000 pulses/second at 30 µm tin droplets traveling at 70 m/s. Each droplet is hit twice — a pre-pulse flattens it, then the main pulse creates a 13.5 nm-emitting plasma. Source power: 250–500W.
- Collector mirror: A huge ellipsoidal mirror (with Mo/Si multilayer coating) captures 5 sr of the emitted EUV light and focuses it to the intermediate focus.
- Illuminator & projection optics: 11 total mirrors, each with >65% reflectivity. Combined optical efficiency is ~2%, so the 250W source delivers only ~5W at the wafer.
- Vacuum system: The entire optical path is in ultra-high vacuum. Hydrogen gas flows over mirrors to remove tin debris.
- Reticle handling: EUV masks are reflective and must be stored and transported in special protective pods (no pellicle was available initially).
An EUV scanner contains 100,000+ parts, weighs 180 tons, requires 3 cargo planes to ship, and costs $350+ million.
Key Concept: High-NA EUV
ASML's next-generation High-NA EUV (0.55 NA vs 0.33 NA) will use anamorphic optics (different magnification in X and Y) and a larger mirror set. It enables single-exposure patterning at ~8 nm half-pitch. Cost: $380+ million per tool.
Knowledge Check
Knowledge Check
1 / 1How many parts does an EUV scanner contain?