Solid state imaging device with inner lens and manufacture thereof
View Patent ↗A semiconductor structure is formed which has photosensors, vertical CCDs, a horizontal CCD and a light shielding film. A first insulating layer made of additive-containing silicon oxide is formed on the semiconductor structure. It is reflowed and upward and downward convex inner lenses are formed on the reflowed first insulating layer and above the photosensors. A second insulating layer is formed which covers the inner lenses and is made of silicon oxide based insulator. It is planarized. Color filters are formed on the planarized surface of the second insulating layer. A transparent flat layer made of transparent material is formed covering the color filters. Micro lenses are formed on the transparent flat layer. A low refractive index layer having a refractive index lower than the micro lenses is formed covering the micro lenses. A transparent plate is disposed on it. The semiconductor structure disposed with the transparent plate is packaged.
1. A solid state imaging device comprising:
a semiconductor substrate having: photosensors disposed in a matrix shape for photoelectrically converting incident light into signal charges; vertical transfer channels for transferring the signal charges generated in the photosensors in a vertical direction; and a horizontal transfer channel for transferring the signal charges supplied from the vertical transfer channels in a horizontal direction;
first and second electrodes formed above the vertical transfer channels and extending in a direction crossing the vertical transfer channels;
a light shielding film formed above said first and second electrodes;
upward and downward convex inner lenses made of silicon nitride, at the height level above said photosensors and at a process level after forming said light shielding film;
micro lenses formed above said inner lenses;
a low refractive index layer covering said micro lenses, said low refractive index layer having a refractive index lower than a refractive index of said micro lenses; and
a transparent plate disposed on said low refractive index layer.
2. The solid state imaging device according to claim 1 , wherein a thickness of said micro lens is 0.5 μm or thinner.
3. The solid state imaging device according to claim 1 , further comprising a plurality of leads connected to said semiconductor substrate.
4. The solid state imaging device according to claim 3 , further comprising an insulating protection plate adhered to a bottom surface of said semiconductor substrate.
5. The solid state imaging device according to claim 1 , wherein said inner lens includes a downward convex lens area and an upward convex lens area.
6. The solid state imaging device according to claim 5 , wherein said upward convex area has a plan shape broader than said downward convex lens area.
7. The solid state imaging device according to claim 5 , wherein said light shielding film increases a height thereof from a surface of said semiconductor substrate near the openings, and said inner lens is formed inside an area where the height of said light shielding film increases.