Solid-state imaging device, manufacturing method and designing method thereof, and electronic device

A method for manufacturing a solid-state imaging device, the method comprising the steps of:

• forming a plurality of photodiodes on a semiconductor substrate, the plurality of photodiodes including a first photodiode associated with a first pixel, a second photodiode associated with a second pixel, and a third photodiode associated with a third pixel;
• forming multilayer wiring on the semiconductor substrate, and forming a first insulating film on the semiconductor substrate so as to cover the multilayer wiring, the first insulating film having a first refractive index lower than a refractive index of the semiconductor substrate for at least bottom surface and top surface portions of the first insulating film;
• forming a second insulating film having a second refractive index higher than the first refractive index on the first insulating film;
• forming a third insulating film having a third refractive index higher than the second refractive index on the second insulating film;
• and
• forming a color filter on the third insulating film, the color filter having at least a first color region for the first pixel to transmit a first color, a second color region for the second pixel to transmit a second color, and a third color region for the third pixel to transmit a third color,
• wherein,
• the second insulating film is provided in each of the first, second, and third pixels, the second insulating film having a step difference between adjacent pixels,
• the third insulating film planarizes the step difference of the second insulating film to provide a planar surface for the color filter, and
• in the step of forming the second insulating film, a thickness and/or the second refractive index of the second insulating film for the first pixel differs from the thickness and/or the second refractive index of the second insulating film for the second pixel so as to reduce variation in intensity of optical interference between reflected light at a surface of the semiconductor substrate, and reflected light at interfaces between the first insulating film and the second insulating film and between the second insulating film and the third insulating film.

A method for designing a solid-state imaging device that includes (a) a semiconductor substrate, (b) a plurality of photodiodes on the semiconductor substrate, the plurality of photodiodes including a first photodiode associated with a first pixel, a second photodiode associated with a second pixel, and a third photodiode associated with a third pixel, (c) a first insulating film on the semiconductor substrate to cover multilayer wiring on the semiconductor substrate, the first insulating film having a first refractive index lower than a refractive index of the semiconductor substrate for at least bottom surface and top surface portions of the first insulating film, (d) a second insulating film having a second refractive index higher than the first refractive index formed on the first insulating film, (e) a third insulating film having a third refractive index higher than the second refractive index and being disposed on the second insulating film, and (f) a color filter on the third insulating film, the color filter having at least a first color region for the first pixel to transmit a first color, a second color region for the second pixel to transmit a second color, and a third color region for the third pixel to transmit a third color, said method comprising:

• designing the solid-state imaging device in such a manner that a thickness and/or the second refractive index of the second insulating film for the first pixel differs from the thickness and/or the second refractive index of the second insulating film for the second pixel, and a variation in intensity of optical interference between reflected light at a surface of the semiconductor substrate, and reflected light at interfaces between the first insulating film and the second insulating film and between the second insulating film and the third insulating film is reduced,
• wherein,
• said designing includes:
• forming the second insulating film in each of the first, second, and third pixels, the second insulating film having a step between adjacent pixels, and
• forming the third insulating film to planarize the step difference of the second insulating film and provide a planar surface for the color filter.

An electronic device comprising:

• a solid-state imaging device;
• an optical system that guides incident light to an imaging section of the solid-state imaging device;
• and
• a signal processing circuit that processes an output signal of the solid-state imaging device,
• wherein
• the solid-state imaging device includes:
• a semiconductor substrate,
• a plurality of photodiodes on the semiconductor substrate, the plurality of photodiodes including a first photodiode associated with a first pixel, a second photodiode associated with a second pixel, and a third photodiode associated with a third pixel;
• a first insulating film on the semiconductor substrate so as to cover multilayer wiring on the semiconductor substrate, the first insulating film having a first refractive index lower than a refractive index of the semiconductor substrate for at least bottom surface and top surface portions of the first insulating film,
• a second insulating film having a second refractive index higher than the first refractive index formed on the first insulating film,
• a third insulating film having a third refractive index higher than the second refractive index formed on the second insulating film, and
• a color filter on the third insulating film, the color filter having at least a first color region for the first pixel to transmit a first color, a second color region for the second pixel to transmit a second color, and a third color region for the third pixel to transmit a third color,
• wherein,
• the second insulating film is provided in each of the first, second, and third pixels, the second insulating film having a step difference between adjacent pixels,
• the third insulating film planarizes the step difference of the second insulating film to provide a planar surface for the color filter, and
• a thickness and/or the second refractive index of the second insulating film of the first pixel differs from the thickness and/or the second refractive index of the second insulating film of the second pixel so as to reduce variation in intensity of optical interference between reflected light at a surface of the semiconductor substrate, and reflected light at interfaces between the first insulating film and the second insulating film and between the second insulating film and the third insulating film.