Solar cell and method of manufacturing the same

1. A solar cell, comprising:

a substrate of a first conductive type having at least one via hole penetrating the substrate;

an emitter layer positioned on an incident surface of the substrate, the emitter layer having a second conductive type opposite the first conductive type;

a passivation layer positioned on an opposite surface to the incident surface of the substrate and on at least a portion of a side wall formed by the substrate in the at least one via hole;

at least one first electrode on the emitter layer positioned on the incident surface of the substrate, the first electrode being directly connected to the emitter layer positioned on the incident surface of the substrate;

a conductive layer positioned on the passivation layer and having at least one second electrode contacted with the opposite surface to the incident surface of the substrate;

at least one first electrode current collector on the passivation layer positioned on the opposite surface to the incident surface of the substrate and on the side wall formed by the substrate in the at least one via hole, the at least one first electrode current collector being insulated from the conductive layer and being connected to the at least one first electrode through the at least one via hole;

wherein the emitter layer is further positioned on the side wall formed by the substrate in the at least one via hole and the passivation layer is further positioned on the emitter layer positioned on the side wall formed by the substrate in the at least one via hole; and

an antireflection layer positioned on the side wall of the at least one via hole.

2. The solar cell of claim 1 , wherein the passivation layer includes at least one layer containing silicon.

3. The solar cell of claim 2 , wherein the passivation layer includes a first passivation layer on the opposite surface of the substrate, a second passivation layer on the first passivation layer, and a third passivation layer on the second passivation layer, and

each of the first, second, and third passivation layers is formed of one of silicon oxide, silicon nitride, silicon oxynitride, or amorphous silicon.

4. The solar cell of claim 3 , wherein the first passivation layer is formed of silicon oxide, the second passivation layer is formed of silicon nitride, and the third passivation layer is formed of silicon oxynitride.

5. The solar cell of claim 3 , wherein each of the first, second, and third passivation layers has a different refractive index.

6. The solar cell of claim 5 , wherein the first passivation layer has a minimum refractive index of the first, second, and third passivation layers, and the second passivation layer has a maximum refractive index of the first, second, and third passivation layers.

7. The solar cell of claim 3 , wherein a thickness of the passivation layer formed on the side wall of the at least one via hole varies depending on a formation location of the passivation layer.

8. The solar cell of claim 7 , wherein the thickness of the passivation layer formed on the side wall of the at least one via hole increases as the side wall of the at least one via hole approaches the opposite surface of the substrate.

9. The solar cell of claim 8 , wherein a number of layers constituting the passivation layer formed on the side wall of the at least one via hole increases as the side wall of the at least one via hole approaches the opposite surface of the substrate.

10. The solar cell of claim 1 , wherein the anti-reflection layer is formed of silicon oxide or silicon nitride.

11. The solar cell of claim 1 , further comprising at least one second electrode current collector positioned on the passivation layer and connected to the conductive layer.