Patent ID: 7781715

Claim:
A backside illuminated imaging device that performs imaging by illuminating light from a back side of a semiconductor substrate to generate electric charges in the semiconductor substrate based on the light and reading out the electric charges from a front side of the semiconductor substrate, which comprises: a plurality of first impurity diffusion layers located in the semiconductor substrate and on an identical plane near a front side surface of the semiconductor substrate, the first impurity diffusion layers having a first conductivity and accumulating the electric charges; a plurality of second impurity diffusion layers between the respective first impurity diffusion layers and the front side of the semiconductor substrate, the second impurity diffusion layers having an exposed surface exposed on the front side surface of the semiconductor substrate, having the first conductivity, and functioning as overflow drains for discharging unnecessary electric charges accumulated in the plurality of first impurity diffusion layers; a plurality of third impurity diffusion layers between the respective second impurity diffusion layers and the respective first impurity diffusion layers, the third impurity diffusion layers having a second conductivity opposite to the first conductivity, and functioning as overflow barriers of the overflow drains; and an electrode connected to the exposed surface of each of the second impurity diffusion layers.