Provided are methods for manufacturing an image sensor. A method for manufacturing an image sensor can include: forming a readout circuitry on a substrate; forming an electrical junction region in the substrate; forming an interconnection connected to the electrical junction region; and forming an image sensing device on the interconnection. The readout circuitry can be formed on a first substrate. The electrical junction region can be formed in the first substrate to electrically connect the image sensing device with the readout circuitry. The image sensing device can be formed using a second substrate that is then bonded on the interconnection.