According to one embodiment, a solid-state image sensor includes a semiconductor substrate including a first surface on which light enters, and a second surface opposite to the first surface, a pixel region formed in the semiconductor substrate, and including a photoelectric conversion element which converts the incident light into an electrical signal, a peripheral region formed in the semiconductor substrate, and including a circuit which controls an operation of the element in the pixel region, a plurality of interconnects which are formed in a plurality of interlayer insulating films stacked on the second surface, and are connected to the circuit, and a support substrate formed on the stacked interlayer insulating films and the interconnects. An uppermost one of the interconnects formed in an uppermost one of the interlayer insulating films is buried in a first trench formed in the uppermost interlayer insulating film.