A method for manufacturing a solar cell, the method comprising: forming an emitter region of a second conductivity type opposite a first conductivity type at a front surface of a semiconductor substrate of the first conductivity type, and forming a back surface field region, which is more heavily doped than the semiconductor substrate with impurities of the first conductivity type, at a back surface of the semiconductor substrate; forming a front passivation part on the front surface of the semiconductor substrate, and forming a back passivation part on the back surface of the semiconductor substrate; and forming a front electrode part, which passes through the front passivation part and is electrically connected to the emitter region, on the front surface of the semiconductor substrate and forming a back electrode part, which passes through the back passivation part and is electrically connected to the semiconductor substrate, on the back surface of the semiconductor substrate, wherein the forming of the front passivation part and the back passivation part includes: forming a front aluminum oxide (AlOx) layer on the front surface of the semiconductor substrate and forming a back aluminum oxide (AlOx) layer on the back surface of the semiconductor substrate; annealing the front and back aluminum oxide layers (133, 163) on the front surface and the back surface of the semiconductor substrate at a temperature of about 450 °C to 700 °C to form a silicon oxide (SiOx) layer (131, 161) having a thickness of about 1 nm to 3 nm between the front aluminum oxide layer and the front surface of the semiconductor substrate and between the back aluminum oxide layer and the back surface of the semiconductor substrate; and removing one of the front aluminum oxide layer on the front surface of the semiconductor substrate and the back aluminum oxide layer on the back surface of the semiconductor substrate, when the first conductivity type of the semiconductor substrate is an n-type, the back aluminum oxide layer on the back surface of the semiconductor substrate is removed, and when the first conductivity type of the semiconductor substrate is a p-type, the front aluminum oxide layer on the front surface of the semiconductor substrate is removed. forming an emitter region of a second conductivity type opposite a first conductivity type at a front surface of a semiconductor substrate of the first conductivity type, and forming a back surface field region, which is more heavily doped than the semiconductor substrate with impurities of the first conductivity type, at a back surface of the semiconductor substrate; forming a front passivation part on the front surface of the semiconductor substrate, and forming a back passivation part on the back surface of the semiconductor substrate; and forming a front electrode part, which passes through the front passivation part and is electrically connected to the emitter region, on the front surface of the semiconductor substrate and forming a back electrode part, which passes through the back passivation part and is electrically connected to the semiconductor substrate, on the back surface of the semiconductor substrate, wherein the forming of the front passivation part and the back passivation part includes: forming a front aluminum oxide (AlOx) layer on the front surface of the semiconductor substrate and forming a back aluminum oxide (AlOx) layer on the back surface of the semiconductor substrate; annealing the front and back aluminum oxide layers (133, 163) on the front surface and the back surface of the semiconductor substrate at a temperature of about 450 °C to 700 °C to form a silicon oxide (SiOx) layer (131, 161) having a thickness of about 1 nm to 3 nm between the front aluminum oxide layer and the front surface of the semiconductor substrate and between the back aluminum oxide layer and the back surface of the semiconductor substrate; and removing one of the front aluminum oxide layer on the front surface of the semiconductor substrate and the back aluminum oxide layer on the back surface of the semiconductor substrate, forming a front aluminum oxide (AlOx) layer on the front surface of the semiconductor substrate and forming a back aluminum oxide (AlOx) layer on the back surface of the semiconductor substrate; annealing the front and back aluminum oxide layers (133, 163) on the front surface and the back surface of the semiconductor substrate at a temperature of about 450 °C to 700 °C to form a silicon oxide (SiOx) layer (131, 161) having a thickness of about 1 nm to 3 nm between the front aluminum oxide layer and the front surface of the semiconductor substrate and between the back aluminum oxide layer and the back surface of the semiconductor substrate; and removing one of the front aluminum oxide layer on the front surface of the semiconductor substrate and the back aluminum oxide layer on the back surface of the semiconductor substrate, when the first conductivity type of the semiconductor substrate is an n-type, the back aluminum oxide layer on the back surface of the semiconductor substrate is removed, and when the first conductivity type of the semiconductor substrate is a p-type, the front aluminum oxide layer on the front surface of the semiconductor substrate is removed.