Image sensor and method for manufacturing the same

1. A method for manufacturing an image sensor, comprising the steps of:

forming a pixel array including a photodiode structure and an insulating film structure in an active area of a semiconductor substrate;

forming a metal pad on the insulating film structure;

forming a dielectric film on the metal pad and over the pixel array;

forming a protective layer on the dielectric film;

forming a pad opening and a pixel opening by etching the protective layer over the metal pad and over the pixel array;

selectively removing the dielectric film in the pixel opening such that the dielectric film remains in the pad opening;

forming a color filter array in the pixel opening, wherein the remaining dielectric film in the pad opening protects the metal pad when forming the color filter array; and

removing the remaining dielectric film in the pad opening.

2. The method according to claim 1 , wherein the dielectric film comprises a nitride film.

3. The method according to claim 1 , wherein the pad opening and the pixel opening are simultaneously formed.

4. The method according to claim 3 , wherein etching the pad opening and the pixel opening comprises a reactive ion etching process.

5. The method according to claim 3 , wherein the dielectric film comprises an etch stop layer.

6. The method according to claim 5 , wherein the etch stop layer is formed on both the metal pad and the insulating film structure.

7. The method according to claim 1 , wherein the protective layer comprises a USG film and a nitride film.

8. The method according to claim 1 , further comprising forming microlenses on the color filter array.

9. An image sensor comprising:

a pixel array including a photodiode structure and an insulating film structure in an active area of a semiconductor substrate;

a metal pad on the insulating film structure;

a dielectric film on the metal pad and the insulating film structure;

a protective layer on the metal pad and the dielectric film;

a pad opening in the protective layer exposing the dielectric film on an upper surface of the metal pad and a pixel opening in the protective layer, the pixel opening exposing a surface of the insulating film structure; and

a color filter array on the exposed surface of the insulating film structure in the pixel opening.

10. The image sensor according to claim 9 , wherein the protective layer comprises a USG film and a nitride film.

11. The image sensor according to claim 9 , wherein the dielectric film comprises a nitride film.

12. The image sensor according to claim 11 , further comprising microlenses on or over the color filter array.

13. The method according to claim 1 , wherein color filters in the color filter array are formed at different heights.

14. The image sensor according to claim 9 , wherein a first color filter in the color filter array has a first height, a second color filter in the color filter array has a second height different from the first height, and a third color filter in the color filter array has a third height different from the first and second heights.

15. The image sensor according to claim 9 , wherein the pad opening and the pixel opening are formed simultaneously.

16. The image sensor according to claim 9 , wherein the dielectric film and the protective layer are on peripheral edges of the metal pad.

17. The image sensor according to claim 16 , wherein the dielectric film and the protective layer are over peripheral portions of the pixel array.

18. The image sensor according to claim 6 , wherein the insulating film structure has a planar upper surface.

19. The image sensor according to claim 9 , wherein the dielectric film and the protective layer are over peripheral portions of the pixel array.

20. The method according to claim 1 , wherein the insulating film structure has a planar upper surface.