Design and fabrication of miniaturized dielectric interference coatings

Miniaturized interference filters were designed and fabricated using three different manufacturing technologies. Applying micro-milled ceramic masks during the coating processes different arrays of interference filters with 1 mm lateral feature size were arranged on a 3-inch Si-substrate. The spectral sensitivity of receiver cells has been modified by direct coating using ion assisted deposition (IAD) at low temperature. IAD-processes also allow the application of microlithographic masks, which are removable by organic solvents after the deposition process. As an example three different miniaturized interference filters were arranged side by side with lateral filter dimensions of a few tens of microns. A combination of coating processes, microlithographic masking procedures, and reactive ion etching made it possible to arrange three different stripe filters with minimum filter features of about 5 mm side by side.