| 摘要 |
PROBLEM TO BE SOLVED: To prevent both the upper and lower surfaces of an assembled wiring board from being etched insufficiently or excessively by eliminating the variations of etching rate on the surfaces. SOLUTION: While an assembled wiring board 1 is transferred horizontally by means of a roller equipped with disks 4, the metallic layers on both the upper and lower surfaces of the board 1 are simultaneously etched with etchants respectively sprayed from upper and lower sprays 6 and 7. The disks 4 are arranged, in such a way that the disks 4 do not come into contact with the wiring board are 2 of the board 1 but makes contact with the extra margin section 3 of the board 1. The spraying pressure of the upper spray 6 is made higher than that of the lower spray 7.
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