A solid-state image sensor and a method for manufacturing thereof and a semiconductor device and a method for manufacturing thereof are provided. A semiconductor substrate is made to be the thin film without using an SOI substrate and cost is reduced. An edge detection portion having hardness larger than that of a semiconductor substrate is formed in the thickness direction of the semiconductor substrate; the semiconductor substrate is made to be the thin film until a position where the edge detection portion is exposed by chemical mechanical polishing from the rear surface; and means Tr1 for reading out a signal from a photoelectric conversion element PD formed in the substrate are formed on the front surface of the semiconductor substrate, where incident light is acquired from the rear surface of the semiconductor substrate.