OTS (February 2007) -- FSI recently collaborated with a key customer to evaluate the ability of the ANTARES^® system AspectClean™ to remove process defects without damaging sensitive gate structures in advanced technology manufacturing processes (90nm and 65nm).

This effort looked at defect removal efficiencies and damage induced by cleaning processes after nitride spacer deposition and post-silicide electrical probing.

Standard cleaning processes are severely limited in these applications. Material removed by chemical treatments such as SC1, though only a few Angstroms, is increasingly unacceptable as feature dimensions and film thicknesses decrease. Moreover these chemical processes are relatively ineffective unless they include megasonic treatments that are themselves damaging. Scrubbers and aerosol processes have also been shown to introduce unacceptable damage to delicate structures in processes below the 130nm node.

Using a new aerosol nozzle design and improved operational knowledge, FSI and IBM were able to demonstrate damage free cleaning at 90nm post spacer nitride with particle removal efficiency (PRE) greater than 90%. The same process showed significantly improved performance compared to an argon based aerosol at post silicide probe cleans on a 90nm high-aspect ratio cobalt silicide process. Finally, the process achieved damage free cleaning with PRE greater than 95% on 65nm nickel silicide, and is now the process of record for this application in high volume production. A complete discussion of this joint work between FSI and IBM will be published in IEEE Transactions on Semiconductor Manufacturing in June 2007.

This collaboration is yet another example of how aerosol cleans are steadily making inroads into mainstream device cleaning. As devices have continued to shrink they have become more vulnerable to damage by conventional cleaning processes and manufacturers have been forced to reduce or eliminate cleaning at the more sensitive process steps. As a result the performance of these processes has declined steadily, their increased defectivity, and the consequent yield loss, regarded as an acceptable compromise. The ability of aerosol processes to delivery highly efficient, damage-free cleaning has allowed manufacturers to reintroduce defect removal cleaning procedures at even the most sensitive process steps, providing yield improvements of several percent in mature processes and greater than 10% for processes earlier in the development cycle. If you would like to learn more about the defect reduction and yield improvement capabilities of the ANTARES^® system, please contact FSI.

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