Imaging element and imaging device
To improve the sensitivity of the imaging element. An imaging element includes pixels and a light guide wall. The pixels each include: a photoelectric conversion unit arranged in a semiconductor substrate to perform photoelectric conversion on incident light, an on-chip lens that concentrates the incident light on the photoelectric conversion unit, a color filter that transmits incident light having a predetermined wavelength within the concentrated incident light, and an interlayer film disposed between the semiconductor substrate and the color filter. The light guide wall is disposed at a boundary of the pixels and formed in a shape of surrounding the color filter, the light guide wall having an end portion disposed in a recess surrounding the pixel formed in the interlayer film at the boundary of the pixels to guide the incident light.
1 . An imaging element, comprising:
a plurality of pixels, wherein each pixel of the plurality of pixels includes:
a semiconductor substrate, wherein
the semiconductor substrate includes a front surface side and a back surface side, and
the front surface side is opposite to the back surface side;
a plurality of wiring layers on the front surface side of the semiconductor substrate;
an interlayer film, wherein
the interlayer film includes a first surface side and a second surface side, and
the second surface side of the interlayer film is on the back surface side of the semiconductor substrate;
a plurality of color filters, wherein
the plurality of color filters includes a first color filter and a second color filter, and
the first color filter and the second color filter are on the first surface side of the interlayer film;
a recess in the interlayer film at a boundary of the plurality of pixels;
a light guide wall bottom film on the recess; and
a light guide wall between the first color filter and the second color filter, wherein
the light guide wall bottom film is between the light guide wall and the recess.
2 . The imaging element according to claim 1 , wherein a refractive index of the light guide wall is different from a refractive index of the first color filter.
3 . The imaging element according to claim 2 , wherein the refractive index of the light guide wall is lower than the refractive index of the first color filter.
4 . The imaging element according to claim 3 , wherein the light guide wall comprises an oxide.
5 . The imaging element according to claim 3 , wherein the light guide wall comprises a resin.
6 . The imaging element according to claim 3 , wherein the light guide wall is a void.
7 . The imaging element according to claim 1 , further comprising a separation portion in the semiconductor substrate, wherein
the plurality of pixels comprises a first pixel and a second pixel,
the first pixel is adjacent to the second pixel, and
the separation portion separates a photoelectric conversion unit of the first pixel from a photoelectric conversion unit of the second pixel.
8 . The imaging element according to claim 1 , wherein the light guide wall bottom film is on side surfaces of the recess.
9 . The imaging element according to claim 1 , wherein the light guide wall bottom film is an etching stopper film.
10 . The imaging element according to claim 1 , wherein the light guide wall bottom film is a film that is configured to block light of a specific wavelength.
11 . The imaging element according to claim 1 , wherein the light guide wall bottom film brings the light guide wall into close contact with the interlayer film.
12 . The imaging element according to claim 1 , wherein the light guide wall bottom film is configured to prevent a movement of contaminants to the semiconductor substrate.
13 . The imaging element according to claim 1 , wherein the light guide wall bottom film comprises a metal.
14 . The imaging element according to claim 1 , wherein the light guide wall bottom film comprises a silicon nitride.
15 . The imaging element according to claim 1 , wherein the light guide wall bottom film comprises an oxide.
16 . The imaging element according to claim 1 , further comprising a protective film between the first color filter and the light guide wall.
17 . An imaging element, comprising:
a plurality of pixels configured to generate an image signal, wherein each pixel of the plurality of pixels includes:
a semiconductor substrate, wherein
the semiconductor substrate includes a front surface side and a back surface side, and
the front surface side is opposite to the back surface side;
a plurality of wiring layers on the front surface side of the semiconductor substrate;
an interlayer film, wherein
the interlayer film includes a first surface side and a second surface side, and
the second surface side of the interlayer film is on the back surface side of the semiconductor substrate;
a plurality of color filters, wherein
the plurality of color filters includes a first color filter and a second color filter, and
the first color filter and the second color filter are on the first surface side of the interlayer film;
a recess in the interlayer film at a boundary of the plurality of pixels;
a light guide wall bottom film on the recess; and
a light guide wall between the first color filter and the second color filter, wherein
the light guide wall bottom film is between the light guide wall and the recess; and
a processing circuit configured to process the image signal.
18 . The imaging element according to claim 1 , wherein the light guide wall bottom film includes a U-shaped bottom surface.