| abstract |
A filter is formed on a substrate, such as a solid state imager, by providing successively on the substrate a layer of an absorber material, a layer of a barrier material, and a layer of a photoresist material. The photoresist is patternwise exposed and developed, thereby baring regions of the barrier layer underlying selected regions of the photoresist layer. The coated substrate is reactive ion etched under a first set of etching conditions to etch away the bared regions of the barrier layer and to bare but not substantially etch the underlying regions of the absorber layer, and then reactive ion etched under a second set of etching conditions, thereby etching away the remaining regions of the photoresist layer and the bared regions of the absorber layer, so forming a filter on the substrate. To form multi-colored filters, the process may be repeated with a different dye, or additional dyes may be deposited by other processes, such as that described in U.S. Pat. No. 4,808,501. |