By MARK LAPEDUS
The overlay metrology equipment market is heating up at advanced nodes as the number of masking layers grows and the size of the features that need to be aligned continue to shrink.
Both ASML and KLA-Tencor recently introduced new overlay metrology systems, seeking to address the increasing precision required for lines, cuts and other features on each layer. At 10/7nm, there may be 80 or more masking layers, versus 40 at 28nm. And if those layers are not precisely measured, the features being patterned, deposited and etched may not line up from one layer to the next.