Solid-state imaging device with light-collecting device having sub-wavelength periodic structure, solid-state imaging apparatus and manufacturing method thereof
The present invention provides a solid-state imaging apparatus and the like which is able to support an optical system whose incident angle is wide. Each pixel is 2.25 μm square in size, and includes a distributed index lens ( 1 ), a color filter (for example, for green) ( 2 ), an Al interconnections ( 3 ), a signal transmitting unit ( 4 ), a planarized layer ( 5 ), a light-receiving device (Si photodiodes) ( 6 ), and an Si substrate ( 7 ). The two-stage concentric circle structure of the distributed index lens is formed by SiO 2 (n=2) with the film thickness 1.2 μm (“grey color”), the film thickness 0.8 μm (“dots pattern”) and the film thickness of 0 μm (“without pattern: white color”), and the medium surrounding the distributed index lens ( 1 )is air (n=1).
1. A solid-state imaging device, comprising:
a light-collector having a modulated effective refractive index distribution comprising a combination of a plurality of zone areas with a plural-stage concentric structure, the plurality of zone areas being divided into line widths which are equal to or shorter than a wavelength of an incident light,
wherein at least one of the plurality of zone areas includes:
a lower light-transmitting film with a first plural-stage concentric structure and having a first line width and a first film thickness; and
an upper light-transmitting film with a second plural-stage concentric structure, configured on said lower light-transmitting film, and having a second line width and a second film thickness,
wherein the plural-stage concentric structure includes a plurality of basic patterns each having a different combination of said upper light-transmitting film and said lower light-transmitting film, and
wherein a width of one of the plurality of basic patterns located in an outer side of the plural-stage concentric structure is smaller than the wavelength of the incident light.
2. The solid-state imaging device according to claim 1 ,
wherein a light-transmitting film, which is formed by combining said upper light-transmitting film and said lower light-transmitting film, forms a convex portion in a part of a vertical cross-section including a center of said light-collector.
3. The solid-state imaging device according to claim 1 ,
wherein a light-transmitting film, which is formed by combining said upper light-transmitting film and said lower light-transmitting film, forms a concave portion in a part of a vertical cross-section including a center of said light-collector.
4. The solid-state imaging device according to claim 1 ,
wherein a light-transmitting film, which is formed by combining said upper light-transmitting film and said lower light-transmitting film, forms a step-like portion in a part of a vertical cross-section including a center of said light-collector.
5. The solid-state imaging device according to claim 1 ,
wherein a light-transmitting film, which is formed by combining said upper light-transmitting film and said lower light-transmitting film, forms a rectangular portion in a part of a vertical cross-section including a center of said light-collector.
6. The solid-state imaging device according to claim 1 ,
wherein an effective refractive index on a light incoming side is lower than an effective refractive index on a light outgoing side in said light-collector.
7. The solid-state imaging device according to claim 1 ,
wherein an effective refractive index on a light outgoing side is lower than an effective refractive index on a light incoming side in said light-collector.
8. The solid-state imaging device according to claim 1 ,
wherein, in said light-collector, line widths are defined as approximately λ/2η, where λdenotes the wavelength of the incident light and ηdenotes a refractive index.
9. The solid-state imaging device according to claim 1 ,
wherein the second film thickness is smaller than the first film thickness.
10. The solid-state imaging device according to claim 1 ,
wherein said light-collector is formed by at least two kinds of light-transmitting materials with different refractive indexes.
11. The solid-state imaging device according to claim 1 ,
wherein said light-collector includes one of TiO 2, ZrO 2, Nb 2 O 5, Ta 2 O 5, Si 3 N 4 and Si 2 N 3 .
12. The solid-state imaging device according to claim 1 ,
wherein said light-collector includes one of SiO 2 doped with at least one of B and P and Teraethoxy Silane.
13. The solid-state imaging device according to claim 1 ,
wherein said light-collector includes one of benzocyclobutene, polymethymethacrylate, polyamide and polyimide.
14. The solid-state imaging device according to claim 1 ,
wherein, in said light-collector, a structure of a light-transmitting film in a vertical cross-section including a center of said light-collector, which is formed by combining said upper light-transmitting film and said lower light-transmitting film, differs depending on the wavelength of the incident light.
15. The solid-state imaging device according to claim 1 ,
wherein said light-collector includes a light-transmitting film, which is formed by combining said upper light-transmitting film and said lower light-transmitting film, as an in-layer lens.
16. The solid-state imaging device according to claim 1 ,
wherein a light-transmitting film, which is formed by combining said upper light-transmitting film and said lower light-transmitting film, forms a tapered structure in a cross-section.
17. The solid-state imaging device according to claim 1 ,
wherein a position of said upper light-transmitting film and a position of said lower light-transmitting film are shifted by a predetermined misalignment margin in one of the zone areas.
18. The solid-state imaging device according to claim 10
wherein said light-collector is formed by the at least two kinds of light-transmitting materials that have a difference in refractive index of not more than 0.5.
19. The solid-state imaging device according to claim 10 ,
wherein said light-collector is formed by the at least two kinds of light-transmitting materials that have a difference in refractive index of at least 0.5.
20. The solid-state imaging device according to claim 14 ,
wherein, in said light-collector, the structure of the light-transmitting film differs depending on a focal length setting for a collected light.
21. The solid-state imaging device according to claim 14 ,
wherein, in said light-collector, the structure of the light-transmitting film differs depending on an incident angle of the incident light.
22. A solid-state imager, comprising:
unit pixels that are arranged in a two-dimensional array, each unit pixel including a light-collector, wherein said light-collector has a modulated effective refractive index distribution comprising a combination of a plurality of zone areas with a plural-stage concentric structure, the plurality of zone areas being divided into line widths which are equal to or shorter than a wavelength of an incident light,
wherein at least one of the plurality of zone areas includes:
a lower light-transmitting film with a first plural-stage concentric structure and having a first line width and a first film thickness; and
an upper light-transmitting film with a second plural-stage concentric structure, configured on said lower light-transmitting film, and having a second line width and a second film thickness,
wherein the plural-stage concentric structure includes a plurality of basic patterns, each having a different combination of said upper light-transmitting film and said lower light-transmitting film, and
wherein a width of one of the plurality of basic patterns located in an outer side of the plural-stage concentric structure is smaller than the wavelength of the incident light.
23. The solid-state imager according to claim 22 ,
wherein a center of the plural-stage concentric structure of said light-collector is offset from a center of the unit pixel.
24. The solid-state imager according to claim 22 ,
wherein said light-collector is formed on a whole area of a corresponding unit pixel.
25. The solid-state imager according to claim 22 ,
wherein a total thickness of the first film thickness and the second film thickness in said light-collector in a unit pixel located in a center of said solid-state imager is greater than a total thickness of the first film thickness and the second film thickness in said light-collector in a unit pixel located near an edge of said imager.
26. A solid-state imager, comprising:
unit pixels that are arranged in a two-dimensional array, each unit pixel including a light-collector, wherein said light-collector has a modulated effective refractive index distribution comprising combination of a plurality of zone areas with a plural-stage concentric structure, the plurality of zone areas being divided into line widths which are equal to or shorter than a wavelength of an incident light,
wherein at least one of the plurality of zone areas includes:
a lower light-transmitting film with a first plural-stage concentric structure and having a first line width and a first film thickness;
an upper light-transmitting film with a second plural-stage concentric structure, configured on said lower light-transmitting film, and having a second line width and a second film thickness,
wherein said solid-state imager further comprises light-receivers,
wherein a central axis of each of said light-receivers is placed to match a central axis of each of said light-collectors in said unit pixels located proximate to a center of said solid-state imager, and
wherein a central axis of each of said light-receivers and a central axis of each of said light-collectors are placed toward the center of said solid-state imager in said unit pixels located near an edge of said solid-state imager, and
wherein a position at which a refractive index in the refractive index distribution is a maximum value shifts to an incident light side in accordance with an increase of an incident angle in said light-collector.