The invention refers to a solar cell and semiconductor device, and a manufacturing method thereof. It is an object of the present invention to minimize an electrode in a solar cell to minimize the solar cell. The present invention provides a method for manufacturing a solar cell comprising the steps of forming a first electrode layer over a substrate, forming a photoelectric conversion layer over the first electrode layer, forming an organic layer over the photoelectric conversion layer, forming an opening reaching the first electrode layer in the photoelectric conversion layer, and forming a second electrode layer by filling the opening with a conductive paste, wherein the organic layer modifies the surface of the photoelectric conversion layer and a contact angle between the conductive paste and the photoelectric conversion becomes greater. According to the present invention, wettability of a photoelectric conversion layer can be decreased by forming an organic layer on a surface of the photoelectric conversion layer. Thereby an electrode layer and an insulating isolation layer can be thinned.