Semiconductor device
View Patent ↗The invention provides a semiconductor device that solves a problem of reflection of a pattern of a wiring formed on a back surface of a semiconductor substrate on an output image. A reflection layer is formed between a light receiving element and a wiring layer, that reflects an infrared ray toward a light receiving element the without transmitting it to the wiring layer, the infrared ray entering from a light transparent substrate toward the wiring layer through a semiconductor substrate. The reflection layer is formed at least in a region under the light receiving element uniformly or only under the light receiving element. Alternatively, an anti-reflection layer having a function of absorbing the entering infrared ray to prevent transmission thereof may be formed instead of the reflection layer.
1. A semiconductor device comprising:
a semiconductor substrate comprising a front surface and a back surface;
a light receiving element formed on the front surface of the semiconductor substrate;
a transparent substrate attached to the front surface of the semiconductor substrate so as to cover the light receiving element;
a wiring layer formed on the back surface of the semiconductor substrate;
a reflection layer formed on the back surface of the semiconductor substrate and located between the light receiving element and the wiring layer, the reflection layer being configured to reflect an infrared ray passing through the transparent substrate, the light receiving element or the semiconductor substrate back toward the light receiving element so that the light receiving element receives the reflected infrared ray; and
an inorganic film disposed between the reflection layer and the wiring layer so as to be in contact with both the reflection layer and the wiring layer.
2. The semiconductor device of claim 1 , wherein the reflection layer is confined to an area of the back surface of the semiconductor substrate that is a projection of the light receiving element onto the back surface.
3. The semiconductor device of claim 1 , wherein the reflection layer extends to cover a side surface of the semiconductor substrate, and the wiring layer and the inorganic film extend to cover a portion of the reflection layer covering the side surface of the semiconductor substrate so that the reflection layer is between the inorganic film and the side surface of the semiconductor substrate.
4. The semiconductor device of claim 1 , wherein the reflection layer comprises a metal.
5. A semiconductor device comprising:
a semiconductor substrate comprising a front surface and a back surface;
a light receiving element formed on the front surface of the semiconductor substrate;
a transparent substrate attached to the front surface of the semiconductor substrate so as to cover the light receiving element;
a wiring layer formed on the back surface of the semiconductor substrate;
an anti-reflection layer formed on the back surface of the semiconductor substrate and located between the light receiving element and the wiring layer, the anti-reflection layer being made of a metal nitride and being configured to absorb an infrared ray; and
an inorganic film disposed between the anti-reflection layer and the wiring layer so as to be in contact with both the anti-reflection layer and the wiring layer,
wherein the anti-reflection layer extends to cover a side surface of the semiconductor substrate, and the wiring layer and the inorganic film extend to cover a portion of the anti-reflection layer covering the side surface of the semiconductor substrate so that the anti-reflection layer is between the inorganic film and the side surface of the semiconductor substrate.
6. The semiconductor device of claim 5 , wherein the anti-reflection layer comprises an infrared ray absorbent material mixed therein.
7. A semiconductor device comprising:
a semiconductor substrate comprising a front surface, a side surface and a back surface;
a light receiving element formed on the front surface of the semiconductor substrate;
a transparent substrate attached to the front surface of the semiconductor substrate so as to cover the light receiving element;
a light-reflecting layer made of a metal and formed on the semiconductor substrate so as to cover the back surface and the side surface thereof;
an inorganic insulation film formed on the light-reflecting layer so as to cover the back surface and the side surface of the semiconductor substrate; and
a wiring layer formed on the inorganic insulation film so as to cover part of the back surface of the semiconductor substrate and part of the side surface of the semiconductor substrate,
wherein the inorganic insulation film is disposed between the light-reflection layer and the wiring layer so as to be in contact with both the light-reflection layer and the wiring layer.
8. The semiconductor device of claim 7 , wherein the light-reflecting layer covers the entire back surface of the semiconductor substrate and the entire side surface of the semiconductor substrate.
9. The semiconductor device of claim 1 , wherein the reflection layer is made of aluminum, gold or silver.
10. The semiconductor device of claim 7 , wherein the metal is aluminum, gold or silver.
11. The semiconductor device of claim 3 , wherein the reflection layer covers the back surface and the side surface of the semiconductor substrate entirely.
12. The semiconductor device of claim 5 , wherein the anti-reflection layer covers the back surface and the side surface of the semiconductor substrate entirely.