Solid-state image pickup device

Abstract

In a solid-state image pickup device, it is difficult to match an optimum incidence angle corresponding to an image height of a pixel array region with light incidence characteristics of a camera lens, thereby causing image quality deterioration due to sensitivity shading. Respective microlenses are disposed in a two-dimensional manner, i.e., in a row and a column directions. In particular, the microlenses are disposed such that each side of a disposition region where the microlenses are disposed has a concave curve with respect to a line connecting adjacent vertexes of the disposition region. In other words, a distance AH (AV) between center points of a pair of facing sides of the disposition region is set to be smaller than a distance BH (BV) between neighboring vertexes of the disposition region.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a diagram illustrating one example of a circuit configuration of a solid-state image pickup device according to a first embodiment of the present invention;

FIG. 1B is a diagram illustrating another example of a circuit configuration of a solid-state image pickup device according to the first embodiment;

FIG. 1C is a diagram illustrating a cross-sectional view of a pixel disposed in a central portion of a pixel array region;

FIG. 1D is a schematic diagram explaining incidence of light into the pixels disposed in the central and a peripheral portions of the pixel array region;

FIG. 2A is a schematic diagram illustrating a layout of microlenses formed in the pixel array region in the solid-state image pickup device according to the first embodiment;

FIG. 2B is a diagram illustrating an enlarged view of the portion “P” shown in FIG. 2A;

FIG. 3 is a diagram showing a relationship between an image height and an optimum incidence angle for each pixel having each image height;

FIG. 4A is a schematic diagram showing displacement amounts of the microlenses in detail;

FIG. 4B is a schematic diagram showing displacement amounts of color filters in detail;

FIG. 4C is a schematic diagram showing displacement amounts of second metal films in detail;

FIG. 5A is a schematic diagram illustrating a layout of the microlenses in a solid-state image pickup device according to a second embodiment of the present invention;

FIG. 5B is a diagram illustrating an enlarged view of the portion “Q” shown in FIG. 5A;

FIG. 6 is a diagram illustrating a cross-sectional view of a pixel disposed in a central portion of a pixel array region;

FIG. 7 is a diagram showing a relationship between an image height and an optimum incidence angle for pixels;

FIG. 8 is a schematic diagram illustrating a layout of microlenses in a solid-state image pickup device according to a third embodiment of the present invention;

FIG. 9 is a diagram showing a relationship between an image height and an optimum incidence angle for pixels;

FIG. 10A is a schematic diagram illustrating a layout of microlenses in a solid-state image pickup device according to a fourth embodiment of the present invention;

FIG. 10B is a diagram illustrating a second metal film in the solid-state image pickup device according to the fourth embodiment;

FIG. 11A is a diagram illustrating an enlarged view of one example of the portion “R” shown in FIG. 10B;

FIG. 11B is diagram illustrating an enlarged view of another example of the portion “R” shown in FIG. 10B;

FIG. 12A is a schematic diagram showing displacement amounts of the microlenses in detail;

FIG. 12B is a schematic diagram showing displacement amounts of color filters in detail;

FIG. 12C is a schematic diagram showing displacement amounts of second metal films in detail;

FIG. 13A is a diagram showing a relationship between an image height and an angle of a light beam passing through an opening of the second metal film;

FIG. 13B is a diagram showing a relationship between an image height and a displacement amount of a light-shielding film;

FIG. 13C is a diagram showing a relationship between an image height and a coupling capacitance between the first metal film and the second metal film;

FIG. 13D is a schematic diagram illustrating a cross-sectional view of a pixel disposed in a peripheral portion of a pixel array region;

FIG. 14 is a schematic diagram illustrating a configuration of a general amplifying solid-state image pickup device;

FIG. 15A is a schematic diagram illustrating a plane view of a pixel disposed in a central portion of a pixel array region;

FIG. 15B is a schematic diagram illustrating a plane view of a pixel disposed in a peripheral portion in the pixel array region;

FIG. 15C is a schematic diagram illustrating a cross-sectional view of the pixel shown in FIG. 15A;

FIG. 15D is a schematic diagram illustrating a cross-sectional view of the pixel shown in FIG. 15B;

FIG. 16 is a schematic diagram explaining incidence of light into the pixels disposed in the central and peripheral portions of the pixel array;

FIG. 17 is a schematic diagram showing a conventional shrink method.

Claims

1. A solid-state image pickup device, comprising a pixel array region, on a semiconductor substrate, where a plurality of pixels are two-dimensionally disposed in a row direction and a column direction, wherein each of the pixels includes: a photoelectric conversion region; anda microlens for converging light into the photoelectric conversion region,disposition of the microlens is determined for each of the pixels, andthe microlenses are two-dimensionally disposed with different pitches.

2. The solid-state image pickup device according to claim 1, wherein in each of the pixels, a displacement amount between a center of the pixel and a center of the microlens is set to be a value obtained by multiplying a distance between the center of the pixel and a center of the pixel array region by a first coefficient, andthe value of the first coefficient varies depending on respective positions of at least two pixels.

3. The solid-state image pickup device according to claim 1, wherein the microlenses are disposed in a disposition region such that an outer shape of the disposition region has at least one curve which connects two adjacent vertexes of the disposition region and is concave with respect to a line passing through the two adjacent vertexes.

4. The solid-state image pickup device according to claim 3, wherein a distance between a center of the microlens and a center of said each of the pixels is set so as to increase in accordance with an increase in an image height until the image height reaches a predetermined value and to be substantially constant after the image height exceeds the predetermined value.

5. The solid-state image pickup device according to claim 1, wherein the pixel array region includes a plurality of partial regions, each of which includes a plurality of the pixels disposed in a rectangular array, andthe microlenses are disposed so as to have pitches which are different from each other between two neighboring partial regions.

6. The solid-state image pickup device according to claim 5, wherein the partial regions are disposed so as to be point-symmetrical with respect to a center of the pixel array region.

7. The solid-state image pickup device according to claim 5, wherein the pixel array region has a rectangular shape, andvertexes of one of the partial regions are positioned on diagonal lines of the pixel array region.

8. The solid-state image pickup device according to claim 7, wherein the pixel array region includes nine partial regions.

9. The solid-state image pickup device according to claim 5, wherein the pixel array region has a rectangular shape, andvertexes of the partial regions are positioned on an outer edge of the pixel array region.

10. The solid-state image pickup device according to claim 9, wherein the pixel array region includes three partial regions.

11. The solid-state image pickup device according to claim 5, wherein the pixels are disposed such that a pitch between the pixels in a peripheral portion of the pixel array region is greater than a pitch between the pixels in a central portion of the pixel array region.

12. A solid-state image pickup device, comprising a pixel array region, on a semiconductor substrate, where a plurality of pixels are two-dimensionally disposed in a row direction and a column direction, wherein each of the pixels includes: a photoelectric conversion region;a microlens for converging light into the photoelectric conversion region; anda metal film which has an opening formed between the microlens and the photoelectric conversion region,disposition of the opening and the microlens is determined for each of the pixels,the microlenses are two-dimensionally disposed with different pitches, andthe openings are two-dimensionally disposed with constant pitches.

13. The solid-state image pickup device according to claim 12, wherein in said each of the pixels, a displacement amount between a center of said each of the pixels and a center of the microlens is set to be a value obtained by multiplying a distance between the center of said each of the pixels and a center of the pixel array region by a second coefficient,in said each of the pixels, a displacement amount between a center of the opening and a center of said each of the pixels is set to be a value obtained by multiplying a distance between the center of said each of the pixels and the center of the pixel array region by a third coefficient,the value of the second coefficient varies depending on respective positions of at least two pixels, andthe value of the third coefficient is constant irrespective of respective positions of all the pixels.

14. The solid-state image pickup device according to claim 12, wherein the metal film is formed in an uppermost layer of a multi-layer metal film.

15. The solid-state image pickup device according to claim 12, further comprising color filters, each of which is formed between the metal film and the microlens, wherein the color filters are two-dimensionally disposed with different pitches or with constant pitches for each pixel.

16. The solid-state image pickup device according to claim 12, wherein the microlenses are disposed in a disposition region such that an outer shape of the disposition region has at least one curve which connects two adjacent vertexes of the disposition region and is concave with respect to a line passing through the two adjacent vertexes.

17. The solid-state image pickup device according to claim 12, wherein the pixel array region includes a plurality of partial regions, each of which includes a plurality of the pixels disposed in a rectangular array, andthe microlenses are disposed so as to have pitches which are different from each other between two neighboring partial regions.

18. The solid-state image pickup device according to claim 17, wherein the pixel array region has a rectangular shape, andvertexes of the partial regions are positioned on an outer edge of the pixel array region.

19. The solid-state image pickup device according to claim 12, wherein the pixels are disposed such that a pitch between the pixels in a peripheral portion of the pixel array region is greater than a pitch between the pixels in a central portion of the pixel array region.

20. The solid-state image pickup device according to claim 14, wherein the solid-state image pickup device is an amplifying solid-state image pickup device.