Image sensing device and method for forming the same
An image sensing device and a method for forming the same are disclosed. The image sensing device includes a substrate including photoelectric conversion elements, and a grid structure disposed over the substrate. The grid structure includes an inner grid layer, and an outer grid layer formed outside the inner grid layer to provide air layer formed at a side surface and a top surface of the inner grid layer.
1. An image sensing device comprising:
a substrate including photoelectric conversion elements;
color filters disposed over the photoelectric conversion elements; and
a grid structure disposed between adjacent color filters over the substrate,
wherein the grid structure includes:
an inner grid layer; and
an outer grid layer that includes an air layer formed outside the inner grid layer, the air layer covering a side surface and a top surface of the inner grid layer.
2. The image sensing device according to claim 1 , wherein the outer grid layer includes:
a support film formed over the air layer; and
a capping film formed over the air layer and the support film.
3. The image sensing device according to claim 2 , wherein the support film includes at least one of a silicon oxide nitride film and a silicon nitride film.
4. The image sensing device according to claim 2 , wherein the capping film includes:
a first capping film formed at side surfaces of the air layer and the support film and at a top surface of the support film; and
a second capping film formed over the first capping film.
5. The image sensing device according to claim 4 , wherein the first capping film includes an ultra low temperature oxide (ULTO) film.
6. The image sensing device according to claim 2 , wherein the capping film is formed to extend to a region below the color filters and a region along both sides of the grid structure.
7. The image sensing device according to claim 6 , wherein the inner grid layer includes:
a barrier metal layer; and
a metal layer formed over the barrier metal layer.
8. The image sensing device according to claim 7 , wherein the inner grid layer further includes:
an insulation film formed at side surfaces of the barrier metal layer and the metal layer and at a top surface of the metal layer.
9. The image sensing device according to claim 8 , wherein the insulation film is formed to extend to the region below the color filters and is disposed between the substrate and the capping film below the color filters.
10. The image sensing device according to claim 8 , wherein the insulation film includes:
a stacked structure of a nitride film and an oxide film.
11. The image sensing device according to claim 7 , wherein the metal layer has a cross-section formed in any one of a square shape, a triangular shape, and a trapezoidal shape.
12. The image sensing device according to claim 1 , wherein the outer grid layer includes a capping film formed to cover the air layer and extended to a region below the color filters.
13. The image sensing device according to claim 12 , wherein the capping film includes:
a first capping film formed at side surfaces of the air layer and the support film and at a top surface of the support film; and
a second capping film formed over the first capping film.
14. The image sensing device according to claim 13 , wherein the first capping film includes an ultra low temperature oxide (ULTO) film.
15. The image sensing device according to claim 12 , wherein the inner grid layer includes:
a barrier metal layer; and
a metal layer formed over the barrier metal layer.
16. The image sensing device according to claim 15 , wherein the inner grid layer further includes an insulation film formed at side surfaces of the barrier metal layer and the metal layer and at a top surface of the metal layer.
17. The image sensing device according to claim 16 , wherein the insulation film is formed to extend to the region below the color filters and is disposed between the substrate and the capping film below the color filters.
18. The image sensing device according to claim 16 , wherein the insulation film includes a stacked structure of a nitride film and an oxide film.
19. The image sensing device according to claim 15 , wherein the metal layer has a cross-section formed in any one of a square shape, a triangular shape, and a trapezoidal shape.