Matt Cogorno, global product manager for selective removal products, said: “Technology challenges have caused customers to change from a lithography focus to new schemes in order to continue scaling. This allows them to use new materials and create new structures.”
According to Cogorno, the Selectra device allows FinFET fins to be trimmed without losing too much material. “It will also address specific processing challenges when the industry moves to all around gates and can handle the horizontal processing elements which 3D NAND will require.”
Previously, manufacturers could choose between wet and dry etch. Wet etch has struggled as aspect ratios – feature height to the distance between them – have increased. “Surface tension effects pull structures together,” Cogorno said, “and that kills devices. In dry etch, particularly for 3D NAND, there’s more material removed at the top of the stack than at the bottom.”
With Selectra, the company is claiming to offer atomic level precision, uniformity, damage free removal and a ‘greener’ process.
It operates by creating a plasma in the chamber, after which ions that can harm the wafer are removed. This leaves the other chemistries to perform what Cogorno called ‘damage free etch’.
Said to be capable of etching spaces of less than five silicon atoms in width, Selectra is already being used to manufacture FinFET based designs at the 10nm node. “We are seeing pull for the 7nm node,” Cogorno, “and expect more applications in 3D NAND as aspect ratios increase.”
According to Applied Materials, it expects more than 350 Selectra chambers to be in operation by the end of 2016.