| 摘要 |
PROBLEM TO BE SOLVED: To enable even a wafer of large diameter to be etched uniformly at a high etching rate by a method wherein wafers are arranged in an etchant in a direction vertical to their surfaces making their main surfaces vertical in a position, and the adjacent wafers are rotated in opposite directions respec tively. SOLUTION: The peripheral edge of a wafer A5 whose center is offset by (d) from that of a wafer B6 is supported with a main roller 1 and the large diameter part 4d of a sub-roller 4, the peripheral edge of the wafer B6 is supported with a second main roller 2 and the large diameter part 3d of a second sub-roller 3 at right angles with their main surfaces. When the first main roller 1 and the first sub-roller 4 are rotated in a positive direction and the second main roller 2 and the second sub-roller 3 are rotated in an opposite direction, the wafers A5 and B6 are rotated in opposite directions, respectively. Therefore, the momentum of etchant is canceled with each other at a center between the wafers A5 and B6, so that etchant is easily circulated between the wafers A5 and B6.
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