Backside illuminated image sensor
View Patent ↗A backside illuminated image sensor includes a light receiving element disposed in a first substrate, an interlayer insulation layer disposed on the first substrate having the light receiving element, an align key spaced apart from the light receiving element and passing through the interlayer insulation layer and the first substrate, a plurality of interconnection layers disposed on the interlayer insulation layer in a multi-layered structure, wherein the backside of the lowermost interconnection layer is connected to the align key, a passivation layer covering the interconnection layers, a pad locally disposed on the backside of the first substrate and connected to the backside of the align key, a light anti-scattering layer disposed on the backside of the substrate having the pad, and a color filter and a microlens disposed on the light anti-scattering layer to face the light receiving element.
1. A method, comprising:
forming a light-receiving element in a front side of a first substrate;
forming a microlens on a back side of the first substrate;
bonding, to the front side of the first substrate, a second substrate including circuitry configured to process signals from the light-receiving element;
forming a plurality of interconnection layers between the first substrate and the second substrate;
forming an align key that passes through the first substrate and that connects to the plurality of interconnection layers;
grinding the back side of the first substrate to expose the align key; and
forming a pad on the back side of the first substrate and on the align key.
2. The method of claim 1 , further comprising forming a light anti-scattering layer on the back side of the substrate by stacking materials having different refractive indexes.
3. The method of claim 1 , wherein said forming an align key comprises filling a via hole with a conductive material.
4. A method, comprising:
forming a light-receiving element in a front side of a first substrate;
forming a microlens on a back side of the first substrate;
bonding, to the front side of the first substrate, a second substrate including circuitry configured to process signals from the light-receiving element;
forming a plurality of interconnection layers between the first substrate and the second substrate;
forming an align key that passes through the first substrate and that connects to the plurality of interconnection layers;
exposing the align key through the back side of the first substrate; and
forming a pad on the back side of the first substrate and on the align key.
5. The method of claim 4 , further comprising forming a light anti-scattering layer on the back side of the substrate by stacking materials having different refractive indexes.
6. The method of claim 4 , wherein said forming an align key comprises filling a via hole with a conductive material.
7. A method, comprising:
forming a light-receiving element in a substrate;
forming an interlayer insulation layer on a front side of the substrate;
forming an align key spaced apart from the light-receiving element and through the interlayer insulation layer and the substrate;
forming a plurality of interconnection layers on the interlayer insulation layer such that an interconnection layer from the plurality of interconnection layers is connected to the align key;
forming a passivation layer on the plurality of interconnection layers;
forming a pad on a back side of the substrate such that the pad is connected to the align key; and
forming a light anti-scattering layer on the back side of the substrate.
8. The method of claim 7 , wherein said forming a light anti-scattering layer comprises stacking materials having different refractive indexes to form the light anti-scattering layer as a multi-layered structure.
9. The method of claim 8 , wherein said stacking comprises stacking an oxide layer and a nitride layer.
10. The method of claim 8 , wherein said stacking comprises stacking an oxide layer and a carbon-containing layer.
11. The method of claim 7 , wherein said forming an align key comprises filling a via hole with a conductive material.
12. The method of claim 7 , further comprising bonding another substrate to the passivation layer.
13. A method, comprising:
forming a light-receiving element in a front side of a substrate;
forming an interlayer insulation layer on the front side of the substrate;
forming an align key spaced apart from the light-receiving element and through the interlayer insulation layer and the substrate;
forming a plurality of interconnection layers on the interlayer insulation layer; and
forming a microlens on a back side of the substrate such that the microlens is configured to direct light toward the light-receiving element.
14. The method of claim 13 , further comprising forming a pad on the back side of the substrate such that the pad is connected to the align key.
15. The method of claim 13 , wherein said forming an align key comprises filling a via hole with a conductive material that connects the pad to at least one interconnection layer from the plurality of interconnection layers.
16. The method of claim 13 , further comprising forming additional align keys that pass through the interlayer insulation layer and that further connect the pad to the plurality of interconnection layers.
17. The method of claim 13 , further comprising forming a pad on an exposed back side of the plurality of interconnection layers.
18. The method of claim 13 , wherein said forming an align key comprises filling a via hole with an insulating material.
19. The method of claim 13 , further comprising:
forming source regions and drain regions in the substrate; and
forming contact plugs that pass through the interlayer insulation layer and connect the source regions and drain regions to the plurality of interconnection layers.
20. The method of claim 13 , further comprising bonding, to the front side of the substrate, another substrate that includes circuitry configured to process image signals from the substrate.