A method of manufacturing a back side illumination image sensor is provided. The method can include forming an ion implantation layer in a front side of a first substrate, forming a photodetector and a readout circuit on the first substrate, forming an interlayer dielectric layer and a metal line on the front side of the first substrate, bonding a second substrate with the front side of the first substrate, removing a lower portion of the first substrate on the basis of the ion implantation layer, performing an annealing process with respect on a back side of the first substrate, and forming a microlens over the photodetector.