Patent ID: 7005690

Claim:
A solid-state image sensor comprising: a pixel part including photoelectric converter for photoelectrically converting incident light, which is formed in a semiconductor substrate of a first conduction type; an analog circuit part for processing an analog signal outputted by the pixel part; a digital circuit part for digital processing a signal outputted by the analog circuit part; and an input/output circuit part for inputting a signal to an outside or outputting a signal from the outside; the digital circuit part including a first well of a second conduction type different from the first conduction type formed in a second region of the semiconductor substrate surrounding a first region thereof, a first buried diffused layer of the second conduction type buried in the semiconductor substrate in the first region and connected to the first well at the side thereof, a second well of the first conduction type formed near a surface of the semiconductor substrate of the first region; and a first transistor formed on the second well; and the input/output circuit part including a third well of the second conduction type formed in a fourth region of the semiconductor substrate surrounding a third region, a second buried diffused layer of the second conduction type buried in the semiconductor substrate in the third region and connected to the third well at the side thereof, a fourth well of the first conduction type formed near the surface of the semiconductor substrate in the third region, and a second transistor formed on the fourth well.