Thin lightshield process for solid-state image sensors
View Patent ↗An image sensor includes a substrate having photosensitive areas; an insulator spanning the substrate; and a first and second layer of a multi-layer metallization structure, wherein the first layer forms light shield regions over selected portions of the photosensitive area as well forming circuit interconnections and barrier regions to prevent spiking into the substrate or gates at contacts in the non-imaging area; and the second layer spanning the interconnections and barrier regions of the first layer only over the non-imaging areas and the second layer overlays edges of the first layer.
1. An image sensor comprising:
(a) a substrate having a plurality of photosensitive areas;
(b) an insulator spanning the substrate;
(c) a first layer of a multi-layer metallization structure spanning at least a portion of the insulator; wherein the first layer forms a lightshield or interconnect; and
(d) a second layer of a multi-layer metallization structure spanning at least portions of the first layer and extending over one or more edges of the first layer such that the one or more edges are covered by the second layer.
2. The image sensor as in claim 1 , wherein the first layer is titanium and tungsten, and the second layer is aluminum.
3. The image sensor as in claim 1 , wherein the first layer is patterned to reside only in one or more contact holes formed in the insulator and extend over and overlap only a portion of the insulator immediately adjacent the one or more contact holes.
4. A digital camera comprising:
an image sensor comprising:
(a) a substrate having a plurality of photosensitive areas;
(b) an insulator spanning the substrate;
(c) a first layer of a multi-layer metallization structure spanning at least a portion of the insulator; wherein the first layer forms a lightshield or interconnect; and
(d) a second layer of a multi-layer metallization structure spanning at least portions of the first layer and extending over one or more edges of the first layer such that the one or more edges are covered by the second layer.
5. The digital camera as in claim 4 , wherein the first layer is titanium and tungsten, and the second layer is aluminum.
6. The The digital camera as in claim 4 , wherein the first layer is patterned to reside only in one or more contact holes formed in the insulator and extend over and overlap only a portion of the insulator immediately adjacent the one or more contact holes.