An image sensor and its manufacturing method are provided to improve the aspect ratio of a dry etching and productivity by performing the dry etching after a wet etching upon formation of a trench. A wet etching is performed on one surface opposite to the other surface where a light receiving unit(110) is mounted on a wafer(100) to form a wet etching part(610). The light receiving unit receives a light signal to convert it into an electrical signal. A dry etching part(620) is formed on the wet etching part through a dry etching to expose an electrode(130) electrically connected to the light receiving unit. A wire(180) connected to the exposed electrode is formed on the wet and dry etching parts. A bump(400) is formed to be electrically connected to the wire. A wafer junction module is cut in chips.
