Polaroid Corporation

Christopher R Needham

Carl A Chiulli

Stephen F Clark

Microlenses are formed on a solid state imager comprising a substrate having planar radiation-sensitive regions and upstanding electrode regions by forming a conformal layer of a first, low refractive index material on the substrate, and forming a planarized layer of a second, higher refractive index material on top of the layer of first material. The portions of the second material extending down between the upstanding electrode regions act as microlenses deflecting light which would otherwise fall on the radiation-insensitive electrode regions on to the radiation-sensitive regions, thus improving the quantum efficiency of the imager.

Process for forming solid state imager with microlenses

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.

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Beverly, MA, United States of America

Christopher R Needham