Solid-state imaging device
View Patent ↗There is employed a lamination structure of semiconductor substrate in which light receiving part having a photoelectric converting function is formed in an inner portion, and insulating films and wirings. There are provided a wiring layer formed above semiconductor substrate and having a concave portion formed in a place corresponding to a portion disposed above light receiving part, second insulating film having a higher refractive index than insulating films and covering a side surface of the wiring layer facing the concave portion, third insulating film having a lower refractive index than second insulating film and covering the side surface of second insulating film, and fourth insulating film having a higher refractive index than third insulating film and covering the side surface of third insulating film.
1. A solid-state imaging device comprising:
a semiconductor substrate in which a light receiving part having a photoelectric converting function is formed in an inner portion;
a wiring layer having a lamination structure including a first insulating film and a wiring, formed above the semiconductor substrate, and provided with a concave portion in a place corresponding to a portion disposed above the light receiving part;
a second insulating film having a higher refractive index than the first insulating film and formed in such a state as to cover at least a side surface of the wiring layer facing the concave portion;
a third insulating film having a lower refractive index than the second insulating film and formed in such a state as to cover at least a side surface of the second insulating film corresponding to the side surface of the wiring layer facing the concave portion;
a fourth insulating film having a higher refractive index than the third insulating film and formed in such a state as to cover at least a side surface of the third insulating film corresponding to the side surface of the second insulating film; and
an optical waveguide having a double light confinement structure constituted by portions of the second, third and fourth insulting films formed in the concave portion.
2. The solid-state imaging device according to claim 1 , wherein the second insulating film is formed in such a state as to also cover a bottom surface of the concave portion,
the third insulating film is formed in such a state as to also cover a bottom surface of the second insulating film corresponding to the bottom surface of the concave portion, and
the fourth insulating film is formed in such a state as to also cover a bottom surface of the third insulating film corresponding to the bottom surface of the second insulating film.
3. The solid-state imaging device according to claim 1 , wherein the fourth insulating film is formed in such a state as to fill a concave portion which is left on an inside of the side surface of the third insulating film in the concave portion of the wiring layer, and the place corresponding to the portion disposed above the light receiving part is formed to take an upward convex shape.
4. The solid-state imaging device according to claim 3 , wherein a grid-shaped partition wall having the opened place corresponding to the portion disposed above the light receiving part is provided on the fourth insulating film, and
a color filter is embedded in the opening.
5. The solid-state imaging device according to claim 4 , wherein the fourth insulating film has a higher refractive index than the color filter.
6. The solid-state imaging device according to claim 4 , wherein the partition wall is formed of an oxide.
7. The solid-state imaging device according to claim 1 , wherein the second insulating film is formed of silicon nitride.
8. The solid-state imaging device according to claim 1 , wherein the fourth insulating film is formed of silicon nitride.
9. The solid-state imaging device according to claim 1 , wherein the third insulating film is formed of silicon oxide or silicon oxynitride.