SPIE Photonics Focus

“In the old days, all you needed was an optical microscope,” says Alain Diebold, professor emeritus and Empire Innovation Professor of Nanoscale Science at SUNY Polytechnic Institute and author of the Handbook of Silicon Semiconductor Metrology.

However, as Moore’s law pushes transistors down to the size of a few atoms, metrology has become ever more critical, and equally challenging. As deep UV immersion lithography at 193 nm wavelength gives way to extreme UV lithography (EUV) with a 13.5 nm wavelength, the size of the smallest etch pattern has shrunk from 40 nm to about 9 nm. At this scale, quantum mechanics and statistics come together to create chaos, resulting in random patterning errors that are not well understood and hard to eliminate.

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