Nanometrics employs scanning white light interferometry as a method to obtain quantitative noncontact, 3D measurements in front-end and back-end of line semiconductor manufacturing applications. Used in Nanometrics’ UniFire family of products, the technology utilizes a white light beam which passes through a filter and then a microscope objective lens to the surface of the semiconductor wafer. The light reflecting back from the surface is combined with the reference beam and captured for software analysis. After obtaining data for each point, the system can generate a 3D image (topography) of the surface.
With its broad capability, it is possible to measure local step height, critical dimensions (CD), overlay, multilayer film thickness and optical properties, combined topography and film thickness, and wafer bow. The technology has particular strength in new advanced packaging applications for process control of through-silicon vias, microbumps, redistribution layers, copper studs and pillars.