June 27, 2007 – FSI International says it has been granted a US patent (#7,235,495) for a surface preparation method of forming an ultrathin silicon oxide layer prior to depositing high-k film.
Depositing the required ultrathin silicon oxide film (<5Å) before depositing a high-k film is difficult to achieve, but FSI says the new method, an oxide growth and etchback process, achieves this with both thinness and uniformity. The process is incorporated into FSI’s “SymFlow” technology, integrated into the company’s surface tension gradient rinse/dry process for its Magellan immersion cleaning system.
“This new method, in combination with FSI’s other high-k selective etching method, allows us to supply customers with effective solutions for advanced gate stack fabrication,” said Jeffery Butterbaugh, FSI’s chief technologist.
Weeks ago FSI touted another US patent for a process combining a rinse/dry step in a single immersion tank, also part of the SymFlow technology.