Wire electric discharge machining method, semiconductor wafer manufacturing method, and solar battery cell manufacturing method

A semiconductor wafer manufacturing method, comprising:

• applying a pulse voltage having a pulse width in a range from 1 μsec to 4 μsec, and having a peak current, at the time of machining with a wire electrode, in a range from 10 A to 50 A, to the wire electrode;
• generating an electric discharge pulse between the wire electrode and a semiconductor material having a volume resistivity in a range from 0.5 Ω·cm to 5 Ω·cm;
• and
• slicing the semiconductor material to manufacture a thin-plate shaped semiconductor wafer.

A solar battery cell manufacturing method, comprising:

• applying a pulse voltage having a pulse width in a range from 1 μsec to 4 μsec, and having a peak current, at the time of machining using a wire electrode, in a range from 10 A to 50 A, to the wire electrode;
• generating an electric discharge pulse between the wire electrode and a side surface of a solar cell silicon wafer that includes an n+ diffused region;
• and
• separating a light detecting surface and a diffusion surfaces at a rear surface of the wafer by removing the n+ region through a p-n separating process to manufacture a solar battery cell.