Wafer Alignment

InGaAs cameras are sensitive from 900nm to 1800nm in the Short Wavelength Infra-Red (SWIR) range of the electromagnetic spectrum.

This makes SWIR cameras extremely interesting in the monitoring of wafer bon-ding process since in the SWIR, pure silicon is transparent at room temperature, while heavily doped silicon becomes more and more opaque as the temperature increases (>200°C). 
Imaging wafer plates using modern SWIR cameras such as the OW1.7-CL-320 or OW1.7-CL-640 allows for extremely precise alignment thanks to their high sensitivity, speed, and ease of use. 
With the right alignment markings and procedure, accuracies better than 5µm have been achieved using the Raptor Photonics’ OW1.7-CL-320.

Highlighted application notes