What have materials got to do with it?

Unsung heroes

Chemistry and materials science are perhaps lesser-known fields of expertise at ASML, even though they’re important to the semiconductor industry in general.  “ASML is by tradition about mechanics, mechatronics, physics and optics,” says Antoine. “That’s where the heart of the company is – but in order to make all that, you need materials, and thus knowledge of chemistry and materials science.”

Antoine notes that chemistry and materials science are sometimes seen as sources of problems rather than solutions. “And yes, they do occasionally cause problems,” he admits. “If you have an issue where a part wears out prematurely, you can say, ‘Well, the material is not good’. But they are also increasingly part of the solution. I'm proud to be the first fellow at ASML with a materials science background.”

ASML’s lithography machines use ultraviolet light to ‘print’ patterns on silicon wafers that form the basis of a microchip. In our EUV machines, the light is generated in a special way: by firing laser pulses at droplets of tin to vaporize them into a plasma that emits EUV light.

The plasma can easily damage materials, though, and the optical components in lithography machines are extremely sensitive. For example, the component closest to the plasma is the collector mirror. Only a short distance and a bit of hydrogen gas separate the collector from the tin droplets being vaporized, and the collector can be ruined by just a few nanometers of contamination.

“We’ve been working on finding materials that are resistant to these circumstances,” says Antoine. “Liquid metals, including tin, are harmful toward almost all other materials, and in combination with hydrogen plasma they are virtually impossible to deal with.”