Solid-state imaging element and electronic device
The present disclosure relates to a solid-state imaging element capable of suppressing stray light with respect to a charge storage unit such as an FD, and an electronic device. According to an aspect of the present disclosure, a solid-state imaging element constituted by many pixels includes a photoelectric conversion unit formed for each of the pixels and that converts incident light into a charge; a charge storage unit that temporarily holds the converted charge; and a first light shielding unit formed between the pixels and having a predetermined length in a thickness direction of a substrate. The charge storage unit is formed below a cross portion where the first light shielding unit formed between pixels adjacent to each other in a longitudinal direction crosses the first light shielding unit formed between pixels adjacent to each other in a lateral direction. The present disclosure can be applied to, for example, a backside irradiation type CMOS image sensor.
1. A solid-state imaging element, comprising:
a plurality of pixels;
a photoelectric conversion unit for each pixel of the plurality of pixels, wherein the photoelectric conversion unit is configured to convert incident light into a charge;
a charge storage unit configured to temporarily hold the charge;
a first light shielding unit between the plurality of pixels and having a determined length in a thickness direction of a substrate, wherein
the charge storage unit is below a cross portion where the first light shielding unit between a plurality of first pixels adjacent to each other in a longitudinal direction crosses the first light shielding unit between a plurality of second pixels adjacent to each other in a lateral direction; and
a second light shielding unit covering a light incident surface side of the cross portion.
2. The solid-state imaging element according to claim 1 , wherein
the cross portion is in a columnar shape or a polygonal pillar shape.
3. The solid-state imaging element according to claim 1 , wherein
the cross portion is in a cylindrical shape or a polygonal tubular shape.
4. The solid-state imaging element according to claim 3 , wherein
the charge storage unit is extended in the thickness direction of the substrate in a tube of the cross portion formed in a tubular shape.
5. The solid-state imaging element according to claim 1 , wherein
the first light shielding unit and the cross portion are formed individually at different etching rates.
6. The solid-state imaging element according to claim 1 , further comprising:
a TG transistor;
an AMP transistor;
a SEL transistor;
an OFG transistor; and
an RST transistor, wherein
the charge storage unit and a source of the RST transistor are integrally formed.
7. The solid-state imaging element according to claim 6 , further comprising a feedback enable (FBEN) transistor configured to suppress reset noise.
8. The solid-state imaging element according to claim 6 , wherein
a drain of the AMP transistor and a drain of the RST transistor share a wire and are connected to a VDD.
9. The solid-state imaging element according to claim 1 , further comprising a moth eye structure unit configured to irregularly reflect the incident light to the photoelectric conversion unit.
10. The solid-state imaging element according to claim 1 , wherein
in the first light shielding unit, lengths in a planar direction of the substrate in adjacent pixel regions are different from each other.
11. The solid-state imaging element according to claim 1 , wherein
in the first light shielding unit, lengths in the thickness direction of the substrate in adjacent pixel regions are different from each other.
12. The solid-state imaging element according to claim 1 , wherein
the photoelectric conversion unit of a first pixel of the plurality of pixels has a different volume from the photoelectric conversion unit of a second pixel of the plurality of pixels, and
the second pixel is adjacent to the first pixel.
13. The solid-state imaging element according to claim 1 , wherein
the plurality of pixels includes:
at least a first pixel sensitive to light having a first wavelength;
a second pixel sensitive to a second wavelength longer than the first wavelength; and
a third pixel sensitive to a third wavelength longer than the second wavelength.
14. The solid-state imaging element according to claim 13 , wherein
in the first light shielding unit between the first pixel or the second pixel and the third pixel, a length in a planar direction of the substrate in a region of the third pixel is longer than that in a region of the first pixel or the second pixel.
15. The solid-state imaging element according to claim 13 , wherein
in the first light shielding unit between the first pixel or the second pixel and the third pixel, a length in the thickness direction of the substrate in a region of the third pixel is longer than that in a region of the first pixel or the second pixel.
16. The solid-state imaging element according to claim 13 , wherein
the photoelectric conversion unit of the third pixel has a smaller volume than the photoelectric conversion unit of the first pixel or the second pixel.
17. The solid-state imaging element according to claim 13 , wherein
the charge storage unit between the first pixel or the second pixel and the third pixel is at a position closer to the first pixel or the second pixel than the third pixel.
18. The solid-state imaging element according to claim 1 , wherein the charge storage unit is shared by the plurality of pixels.
19. An electronic device, comprising:
a solid-state imaging element, wherein the solid-state imaging element comprises:
a plurality of pixels;
a photoelectric conversion unit for each pixel of the plurality of pixels, wherein the photoelectric conversion unit is configured to convert incident light into a charge;
a charge storage unit configured to temporarily hold the charge;
a first light shielding unit between the plurality of pixels and having a determined length in a thickness direction of a substrate, wherein
the charge storage unit is below a cross portion where the first light shielding unit between a plurality of first pixels adjacent to each other in a longitudinal direction crosses the first light shielding unit between a plurality of second pixels adjacent to each other in a lateral direction; and
a second light shielding unit covering a light incident surface side of the cross portion.