"CHIPS: IBM commits to ultimate dielectric: air gaps"

The road map to advanced semiconductor nodes calls for ultralow-k dielectrics to reduce parasitic capacitance between adjacent metal lines, especially on interconnection layers, at the 32-nanometer node and beyond. Now IBM Corp. has vowed to commercialize the ultimate dielectric--a pure vacuum--between metal lines of its 32-nm chips, thereby reducing parasitic capacitance on interconnection layers by 36 percent.
Text: http://www.eetimes.com/showArticle.jhtml?articleID=199203911