Solid-state image sensing device having a layer on microlens and method for fabricating the same

1. A solid-state image sensing device comprising:

a light receiving unit for receiving light;

a color filter formed above the light receiving unit;

a microlens formed above the color filter and having a first refractive index of n 1 ;

a first material layer formed on the microlens and having a second refractive index of n 2 ; and

a second material layer provided over the first material layer and having a fourth refractive index of n 4 ,

wherein a third material layer adheres the first material layer and the second material layer and has a third refractive index of n 3 ;

the following relations hold: n 3 =(n 2 +n 4 )/2±0.2 and n 1 >n 2 , and

the top surface of the first material layer has a first contour and the top surface of the microlens has a second contour, said first contour and said second contour being shaped differently in an area located above said microlens.

2. The device of claim 1 , wherein the first material layer is a fluorine-containing resin layer.

3. The device of claim 1 , wherein the following relations hold: n 1 >1.60 and n 2 <1.45.

4. The device of claim 1 , wherein the microlens is made of styrene-based positive type resist.

5. The device of claim 1 further comprising:

a color filter formed between the light receiving unit and the microlens.

6. The device of claim 1 , wherein the microlens contains naphthoquinone diazide.

7. The device of claim 1 , wherein a thickness of the first material layer is equal to or more than 0.1 μm.

8. The device of claim 1 , wherein the first material layer is made of acrylic-based resin.

9. The device of claim 1 , wherein the first material layer is made of olefin-based resin.

10. The device of claim 1 , wherein the first material layer is made of silicone-based resin.

11. The device of claim 1 , wherein hollow microparticles of silicon dioxide having a diameter less than 400 nm is dispersed in the first material layer.

12. The device of claim 1 , wherein hollow microparticles of metal oxide having a diameter less than 400 nm is dispersed in the first material layer.

13. The device of claim 1 , wherein the third material layer has a thickness of 2 μm or greater.

14. The device of claim 1 , wherein the third material layer is made of acrylic-based resin.

15. The device of claim 1 , wherein the third material layer is made of epoxy resin.

16. The device of claim 1 , wherein the second material layer is made of a glass.

17. The device of claim 1 , further comprising a first flattening film on the light-receiving unit and under the microlens.

18. The device of claim 17 , wherein the first flattening film is acrylic.

19. The device of claim 17 , further comprising a color filter on the first flattening film and under the microlens.

20. The device of claim 19 , further comprising a second flattening film on the color filter and under the microlens.

21. The device of claim 20 , wherein the second flattening film is acrylic.

22. The device of claim 19 , wherein the color filter is made of photosensitive resist containing pigment.

23. The device of claim 19 , wherein the color filter is made of photosensitive resist containing dye.

24. The device of claim 19 , wherein the color filter is formed by etching non-photosensitive resist containing pigment.

25. The device of claim 19 , wherein the color filter is formed by etching non-photosensitive resist containing dye.

26. The device of claim 19 , wherein the color filter is complementary color.

27. The device of claim 19 , wherein the color filter is primary color.

28. The device of claim 1 , wherein the first refractive index of n 1 is 1.65.

29. The device of claim 1 , wherein the second refractive index of n 2 is 1.41.

30. The device of claim 1 , wherein the third refractive index of n 3 is 1.26.

31. The device of claim 1 , wherein the third refractive index of n 3 is 1.46.

32. The device of claim 1 , wherein the third refractive index of n 3 is 1.66.

33. The device of claim 1 , wherein the forth refractive index of n 4 is 1.52.

34. The device of claim 1 , wherein the top surface of the first material layer is flat.

35. The device of claim 1 , wherein an unevenness of the top surface of the first material layer is 300 nm or less.

36. A method for fabricating a solid-state image sensing device, comprising the steps of:

forming, above a light receiving unit for receiving light, a color filter;

forming, above the color filter, a microlens having a first refractive index of n 1 ;

forming, on the microlens, a fluorine-containing resin material layer having a second refractive index of n 2 ;

forming, on the fluorine-containing resin material layer, a resin layer having a third refractive index of n 3 ; and

providing, on the resin layer, a transparent substrate having a fourth refractive index of n 4 ;

wherein the following relations hold: n 3 =(n 2 +n 4 )/2±0.2 and n 1 >n 2 , and

the top surface of the fluorine-containing material layer has a first contour and the top surface of the microlens has a second contour, said first contour and said second contour being shaped differently in an area located above said microlens.

37. The method of claim 36 , wherein the first material layer is formed by spin coating.

38. The method of claim 36 , further comprising the step of subjecting the surface of the first material layer to oxygen plasma treatment.

39. The method of claim 36 , wherein an unevenness of the top surface of the fluorine-containing material layer is 300 nm or less.

40. A solid-state image sensing device comprising:

a light receiving unit for receiving light;

a microlens formed above the light receiving unit and having a first refractive index of n 1 ;

a first material layer formed on the microlens and having a second refractive index of n 2 ; and

a second material layer provided over the first material layer and having a fourth refractive index of n 4 ,

wherein a third material layer adheres the first material layer and the second material layer and has a third refractive index of n 3 ;

the following relations hold: n 3 =(n 2 +n 4 )/2±0.2 and n 1 >n 2 , and

the top surface of the first material layer has a curve shape in an area located above said each microlens, a height of the each microlenses is greater than a height from a bottom of the curve shape to a top of the curve shape of the first material layer.

41. The device of claim 40 , wherein the first material layer is a fluorine-containing resin layer.

42. The device of claim 40 , wherein the following relations hold: n 1 >1.60 and n 2 <1.45.

43. The device of claim 40 , wherein the microlens is made of styrene-based positive type resist.

44. The device of claim 40 further comprising:

a color filter formed between the light receiving unit and the microlens.

45. The device of claim 40 , wherein the microlens contains naphthoquinone diazide.

46. The device of claim 40 , wherein a thickness of the first material layer is equal to or more than 0.1 μm.

47. The device of claim 40 , wherein the first material layer is made of acrylic-based resin.

48. The device of claim 40 , wherein the first material layer is made of olefin-based resin.

49. The device of claim 40 , wherein the first material layer is made of silicone-based resin.

50. The device of claim 40 , wherein hollow microparticles of silicon dioxide having a diameter less than 400 nm is dispersed in the first material layer.

51. The device of claim 40 , wherein hollow microparticles of metal oxide having a diameter less than 400 nm is dispersed in the first material layer.

52. The device of claim 40 , wherein the third material layer has a thickness of 2 μm or greater.

53. The device of claim 40 , wherein the third material layer is made of acrylic-based resin.

54. The device of claim 40 , wherein the third material layer is made of epoxy resin.

55. The device of claim 40 , wherein the second material layer is made of a glass.

56. The device of claim 40 , further comprising a first flattening film on the light-receiving unit and under the microlens.

57. The device of claim 56 , wherein the first flattening film is acrylic.

58. The device of claim 56 , further comprising a color filter on the first flattening film and under the microlens.

59. The device of claim 58 , further comprising a second flattening film on the color filter and under the microlens.

60. The device of claim 58 , wherein the color filter is made of photosensitive resist containing pigment.

61. The device of claim 58 , wherein the color filter is made of photosensitive resist containing dye.

62. The device of claim 58 , wherein the color filter is formed by etching non-photosensitive resist containing pigment.

63. The device of claim 58 , wherein the color filter is formed by etching non-photosensitive resist containing dye.

64. The device of claim 58 , wherein the color filter is complementary color.

65. The device of claim 58 , wherein the color filter is primary color.

66. The device of claim 40 , wherein the second flattening film is acrylic.

67. The device of claim 40 , wherein the first refractive index of n 1 is 1.65.

68. The device of claim 40 , wherein the second refractive index of n 2 is 1.41.

69. The device of claim 40 , wherein the third refractive index of n 3 is 1.26.

70. The device of claim 40 , wherein the third refractive index of n 3 is 1.46.

71. The device of claim 40 , wherein the third refractive index of n 3 is 1.66.

72. The device of claim 40 , wherein the forth refractive index of n 4 is 1.52.

73. The device of claim 40 , wherein the top surface of the first material layer is flat.

74. The device of claim 40 , wherein an unevenness of the top surface of the first material layer is 300 nm or less.