Method of manufacturing solar cell

1. A method of manufacturing a solar cell including a substrate made of a semiconductor material, comprising:

processing substrates arranged in one direction by immersing the substrates in a chemical solution, and by agitating the chemical solution by simultaneously supplying gas bubbles to the substrates into the chemical solution, wherein

in the processing, the gas bubbles are supplied from supplying portions positioned at respective positions between respective adjacent substrates of the substrates,

in the processing, the gas bubbles are supplied so as to bring about a first state and a second state for each substrate of the substrates, the first state and the second state occurring in alternate ones of the respective positions between the respective adjacent substrates, where the first state is a state in which a first non-zero amount of the gas bubbles supplied to a first side in the one direction of a substrate is greater than a second non-zero amount of the gas bubbles supplied to a second side in the one direction of the substrate, and the second state is a state in which the first amount of the gas bubbles supplied to the first side in the one direction of the substrate is smaller than the second amount of the gas bubbles supplied to the second side in the one direction of the substrate, and the first amount and the second amount of the gas bubbles are supplied simultaneously to the substrates such that the first state and the second state in the substrates occur simultaneously in sides of the respective adjacent substrates exposed to alternating ones of the respective positions; and

the first amount of the gas bubbles and the second amount of gas bubbles are simultaneously supplied so as to cause each of the substrates to swing so as to agitate the chemical solution.

2. The method of manufacturing a solar cell according to claim 1 , wherein

in the first state, the gas bubbles are supplied to the first side in the one direction of the substrate while the gas bubbles are not supplied to the second side in the one direction of the substrate, and

in the second state, the gas bubbles are not supplied to the first side in the one direction of the substrate while the gas bubbles are supplied to the second side in the one direction of the substrate.

3. The method of manufacturing a solar cell according to claim 1 , wherein a position of supply of the gas bubbles on the first side in the one direction of the substrate and a position of supply of the gas bubbles on the second side in the one direction of the substrate are different from each other in an extending direction of the substrate, the extending direction of the substrate perpendicular to the one direction.

4. The method of manufacturing a solar cell according to claim 1 , wherein the processing is performed in a state where the substrates are set in a cassette comprising recesses, each recess extending in a vertical direction, allowing insertion of an end portion in a width direction of the substrate, and containing a space which widens toward the substrate.

5. The method of manufacturing a solar cell according to claim 1 , wherein the substrates are arranged in such a way that an interval between the substrates adjacent to each other is set equal to or below 1/20 of a length of one side of the substrates when a planar shape of the substrates is approximated to a rectangle.

6. The method of manufacturing a solar cell according to claim 1 , wherein a thickness of each substrate is equal to or below 200 μm.

7. The method of manufacturing a solar cell according to claim 1 , wherein the processing includes at least one of cleaning the substrates by immersing the substrates in a cleaning solution, and etching the substrates by immersing substrates in an etching solution.

8. The method of manufacturing a solar cell according to claim 1 , wherein

in the processing, the gas babbles are supplied from holes of pipes, the holes being positioned at the respective positions between the respective adjacent substrates of the substrates and

each pipe extends along the one direction from the first side of a group of the substrates to the second side of the group of the substrates.

9. The method of manufacturing a solar cell according to claim 1 , wherein

the substrates include a first substrate, a second substrate, a third substrate, and a fourth substrate arranged in this order along the one direction,

in the processing,

at a first timing, the first state in the first substrate and the third substrate and the second state in the second substrate and the fourth substrate occur simultaneously, and

at a second timing after the first timing, the second state in the first substrate and the third substrate and the first state in the second substrate and the fourth substrate occur simultaneously,

at a third timing after the second timing, the first state in the first substrate and the third substrate and the second state in the second substrate and the fourth substrate occur simultaneously, and

at a fourth timing after the third timing, the second state in the first substrate and the third substrate and the first state in the second substrate and the fourth substrate occur simultaneously.

10. The method of manufacturing a solar cell according to claim 1 , wherein

the substrates include a first substrate, a second substrate, and a third substrate arranged in this order along the one direction,

in the processing, at any timing,

the state in the first substrate is same as the state in the third substrate,

the state in the second substrate between the first substrate and the second substrate along the one direction is different from the state in the first substrate and the third substrate.