News & Analysis
/
Article

In-situ cleaning technique improves extreme ultraviolet lithography efficiency

SEP 16, 2022
Method could extend collector mirror lifetimes indefinitely, expanding EUVL tool availability.
In-situ cleaning technique improves extreme ultraviolet lithography efficiency internal name

In-situ cleaning technique improves extreme ultraviolet lithography efficiency lead image

Extreme ultraviolet lithography (EUVL) is a promising technology for next-generation microchip fabrication. The challenge is that tin contaminates the collector mirror, which degrades the etching process. Microchip manufacturers address contamination by removing the collector and cleaning it with hydrogen plasma. But the process results in significant EUVL downtime.

Qerimi et al. developed an annular surface wave plasma (SWP) antenna technology that is integrated into the collector for in-situ tin removal. They showed that by affixing eight SWP antennas to the mirror — two to the inner cone and six to the outer perimeter — the collector is kept free from tin buildup during etching.

“Our technique could extend collector lifetimes indefinitely, expanding EUVL tool availability,” author David Ruzic said.

Extreme ultraviolet light with a 13.5 nanometer wavelength is generated by directing a carbon dioxide laser at molten tin droplets, ionizing them into a plasma for etching. The ions interact with the collector wall, causing vapor buildup. Hydrogen plasma is used to break the bonds between the tin particles and collector wall, forming gaseous tin hydride, which is removed through pumping.

The SWP antennas generate hydrogen radicals and atoms at the desired etching locations, enabling high etch rates that surpass the contamination rate by a factor of 20. The researchers found the cleaning efficiency would be even greater if the power for each antenna could be raised. They also tested the arc antenna attached to the perimeter of the collector with varying pressure and discovered plasma coverage increases at lower pressures.

“The goal is to cover every surface exposed to tin vapor with SWP,” Ruzic said.

Source: “Tin removal by an annular surface wave plasma antenna in an extreme ultraviolet source,” by Dren Qerimi, Andrew Herschberg, Gianluca Panici, Parker Hays, Tyler Pohlman and David N. Ruzic, Journal of Applied Physics (2022). The article can be accessed at https://doi.org/10.1063/5.0094375 .

Related Topics
More Science
/
Article
Results can help wind-farm operators adjust their wind farms to maximize energy extracted throughout the day.
/
Article
Understanding how the shape and size of oyster reefs affect pore pressure and wave transmission can help guide efforts to build coastal barriers.
AAS
/
Article
How can we track down colliding neutron stars as quickly as possible? New research shows that the nearly 20-year-old Swift Observatory might be our best bet. The post Old Telescope, New Tricks: Chasing Gravitational Waves Across the Sky appeared first on AAS Nova.
AAS
/
Article
New simulations show how odd radio circles could form when supermassive black hole jets blow bubbles in intergalactic gas. The post A Bubbly Origin for Odd Radio Circles appeared first on AAS Nova.