US Patent 7662648 - IC inspection using nanotube electron emitters

http://www.freepatentsonline.com/7662648.html

Carbon nanotubes have been employed as electron emitters in numerous applications such as flat panel displays, pressure sensors, and as e-beam lithography. This patent from Micron Technology introduces a new application in testing integrated circuits. Claim 1 reads:

1. A method, comprising:

selectively activating one or more nanotubes of a plurality of nanotubes to emit an electrical signal toward aligned regions of a substrate, wherein the one or more nanotubes are alignable with features of the substrate and adapted to emit the signal to the substrate when activated;

sensing a current generated by the electrical signal, the current flowing through the substrate;

comparing the current to a reference current; and

determining whether a via is completely formed in the substrate based on the comparison.