A method for fabricating an image sensor comprises forming an over coat layer on an upper face of a semiconductor substrate on which a color filter layer is formed, forming a microlens on the over coat layer; covering the microlens with a protection layer, back grinding a lower face of the semiconductor substrate, and removing the protection layer of the microlens. In this method, the protection layer is formed on the microlens of an image sensor and is subsequently removed after back grinding.