Back-illuminated solid-state imaging element

1. A back-illuminated solid-state imaging element comprising:

a semiconductor substrate which has a front surface and a back surface provided with a recess, and in which a thinned section which is a bottom section of the recess is an imaging area;

a signal read-out circuit formed on the front surface of the semiconductor substrate;

a boron layer formed on at least the back surface of the semiconductor substrate and a lateral surface of the recess;

a metal layer formed on the boron layer, and provided with an opening opposing a bottom surface of the recess; and

an anti-reflection layer formed on the bottom surface of the recess.

2. The back-illuminated solid-state imaging element according to claim 1 ,

wherein the recess has a frustum shape spreading toward a side opposite to the front surface side of the semiconductor substrate.

3. The back-illuminated solid-state imaging element according to claim 1 ,

wherein the boron layer is further formed on the bottom surface of the recess, and

wherein the anti-reflection layer is formed on the bottom surface of the recess with the boron layer interposed therebetween.

4. The back-illuminated solid-state imaging element according to claim 1 ,

wherein at least a region surrounding the recess in the semiconductor substrate is made of a P type semiconductor material.

5. The back-illuminated solid-state imaging element according to claim 1 ,

wherein the metal layer is a plating layer.