Image sensor

1. An image sensor comprising:

a semiconductor substrate having a first surface and a second surface opposite to the first surface;

a wiring structure disposed on the first surface of the semiconductor substrate; and

a refractive structure on the second surface of the semiconductor substrate,

wherein the refractive structure comprises:

a first anti-reflective layer disposed on the second surface of the semiconductor substrate;

a refractive pattern disposed on the first anti-reflective layer, and including a plurality of first refractive parts spaced apart from each other;

an insulation layer disposed on the first anti-reflective layer, and filling spaces between the plurality of first refractive parts; and

a second anti-reflective layer disposed on the refractive pattern and the insulation layer,

wherein the refractive pattern and the insulation layer are vertically interposed between the first anti-reflective layer and the second anti-reflective layer,

wherein the refractive pattern further comprises a plurality of second refractive parts disposed over the plurality of first refractive parts, and

wherein the second anti-reflective layer is continuously interposed between upper surfaces of the plurality of first refractive parts and lower surfaces of the plurality of second refractive parts.

2. The image sensor according to claim 1 ,

wherein each of the plurality of first refractive parts has a linear shape with a first width in a first direction and extends in a second direction perpendicular to the first direction and parallel to the second surface of the semiconductor substrate.

3. The image sensor according to claim 1 ,

wherein each of the plurality of first refractive parts has an island shape and the plurality of first refractive parts are arranged in a first direction and a second direction perpendicular to the first direction and parallel to the second surface of the semiconductor substrate.

4. The image sensor according to claim 1 ,

wherein the plurality of first refractive parts are connected to each other so that the refractive structure includes a plurality of holes arranged in a first direction and a second direction perpendicular to the first direction and parallel to the second surface of the semiconductor substrate, and

wherein the insulation layer fills the plurality of holes and has a plurality of island shapes separated from each other by the plurality of first refractive parts.

5. The image sensor according to claim 1 ,

wherein each of the plurality of first refractive parts has a first width in a first direction, and

wherein the first width decreases in a direction away from the second surface of the semi conductor substrate.

6. The image sensor according to claim 1 , further comprising:

a passivation layer disposed on the second anti-reflective layer and the plurality of second refractive parts; and

a microlens disposed on the passivation layer.

7. The image sensor according to claim 1 ,

wherein the refractive pattern includes polysilicon, and

wherein a refractive index of the insulation layer is lower than a refractive index of the refractive pattern.

8. The image sensor according to claim 1 ,

wherein the insulation layer includes a plurality of insulation patterns, and

wherein the plurality of insulation patterns are spaced apart from each other, and completely fill spaces between the plurality of first refractive parts.

9. The image sensor according to claim 1 ,

wherein an upper surface of the insulation layer is coplanar with upper surfaces of the plurality of first refractive parts.

10. The image sensor according to claim 1 ,

wherein the plurality of second refractive parts do not vertically overlap the plurality of first refractive parts.

11. An image sensor comprising:

a semiconductor substrate having a first surface and a second surface opposite to the first surface;

a wiring structure disposed on the first surface of the semiconductor substrate; and

a refractive structure on the second surface of the semiconductor substrate,

wherein the refractive structure comprises:

a first anti-reflective layer disposed on the second surface of the semiconductor substrate;

a refractive pattern disposed on the first anti-reflective layer,

wherein the refractive pattern includes a plurality of first refractive parts spaced apart from each other, and the second surface of the semiconductor substrate is flat;

a second anti-reflective layer disposed on the refractive pattern; and

an insulation layer disposed on the first anti-reflective layer, and filling spaces between the plurality of first refractive parts, and

wherein the refractive pattern and the insulation layer are vertically interposed between the first anti-reflective layer and the second anti-reflective layer,

wherein the refractive pattern further comprises a plurality of second refractive parts disposed over the plurality of first refractive parts, and

wherein the second anti-reflective layer is continuously interposed between upper surfaces of the plurality of first refractive parts and lower surfaces of the plurality of second refractive parts.

12. The image sensor according to claim 11 ,

wherein a refractive index of the insulation layer is lower than a refractive index of the refractive pattern.

13. The image sensor according to claim 12 , further comprising:

a passivation layer disposed on the refractive structure; and

a microlens disposed on the passivation layer.

14. The image sensor according to claim 11 ,

wherein each of the plurality of first refractive parts has a first width, and

wherein the first width decreases in a direction away from the second surface of the semiconductor substrate.

15. An image sensor comprising:

a semiconductor substrate having a first surface and a second surface opposite to the first surface;

a wiring structure disposed on the first surface of the semiconductor substrate; and

a refractive structure disposed on the second surface of the semiconductor substrate,

wherein the refractive structure comprises:

a first anti-reflective layer disposed on the second surface of the semiconductor substrate;

a plurality of first refractive parts disposed on the first anti-reflective layer and spaced apart from each other in a first direction parallel to the second surface of the semiconductor substrate;

an insulation layer disposed on the first anti-reflective layer, and filling spaces between the plurality of first refractive parts; and

a second anti-reflective layer disposed on the plurality of first refractive parts and the insulation layer,

wherein the plurality of first refractive parts and the insulation layer are vertically interposed between the first anti-reflective layer and the second anti-reflective layer,

wherein the plurality of first refractive parts include polysilicon,

wherein a refractive index of the insulation layer is lower than a refractive index of each of the plurality of first refractive parts,

wherein the refractive structure further comprises a plurality of second refractive parts disposed over the plurality of first refractive parts, and

wherein the second anti-reflective layer is continuously interposed between upper surfaces of the plurality of first refractive parts and lower surfaces of the plurality of second refractive parts.

16. The image sensor according to claim 15 ,

wherein each of the plurality of first refractive parts is spaced apart from the second surface of the semiconductor substrate, and

wherein an upper surface of the insulation layer is located at the same height as an upper surface of each of the plurality of first refractive parts from the first anti-reflective layer.

17. The image sensor according to claim 15 ,

wherein the insulation layer comprises:

a first insulation layer filling spaces between the plurality of first refractive parts; and

a second insulation layer disposed over the first insulation layer and filling spaces between the plurality of second refractive parts.