Noninvasive Profilometry of Sealed Otto Chip Devices by Scanning Optical Reflectometry

Profilometry carried out on a surface having microscale and nanoscale features is an important diagnosis step, in both the electronics and the photonics industry, as well as in research. Nonetheless, few techniques are available for the structural characterization of buried devices. This work evaluates the suitability of an automated reflectometer to perform scanning optical reflectometry (SOR) analysis of quartz sealed plasmonic devices capable of supporting the surface plasmon resonance (SPR) effect in the Otto configuration. The SOR technique was able to fully characterize the devices for quality of sealing between different materials, as well as to map optical parameters of the metallic films and identification of substrate wear, in an automated and noninvasive way. Devices with 9 and 1.4 cm² of area are characterized, and the minimum gap between layers measured was 0.69 µm. A defective device was also identified through SOR and its defects were confirmed by reflectance microscopy.