| 主权项 |
1. An electrode plate for a plasma etching formed as a disc shape having a predetermined thickness, the electrode plate comprising: a plurality of gas holes through which a gas is able to be discharged,
wherein the electrode plate is divided into at least three regions according to distances from a center of the electrode plate, shapes of the gas holes are different according to the regions, the at least three regions comprising an outermost region, an intermediate region and an innermost region, Y-shaped holes are provided in the outermost region, the Y-shaped holes each comprising: a straight pore penetrating one surface of the electrode plate perpendicularly to the one surface; a sloping pore communicating with the straight pore and penetrating other surface of the electrode plate non-perpendicularly to the other surface; and a trap pore branching from a connecting point between the straight pore and the sloping pore, first inclined holes are provided in the intermediate region, the first inclined holes each consisting of: the straight pore and the sloping pore, and second inclined holes or standard holes are provided in the innermost region, wherein a ratio of length of the straight pore of the second inclined hole to length of the sloping pore of the second inclined hole is larger than a ratio of length of the straight pore of the first inclined hole to length of the sloping pore of the first inclined hole, and each of the standard holes penetrates the electrode plate straight in a thicknesswise direction of the electrode plate. |
