| 摘要 |
PURPOSE:To prevent a single-layered structure part from being bent by a shower pressure at the time of etching by forming dummy patterns to be finally dissipated so as to connect the corresponding parts of the single-layered structure part. CONSTITUTION:Normal patterns 2 corresponding to the wiring patterns on a flexible circuit board are formed on a mask base material 1 and further, the dummy patterns 5 are so formed as to connect the corresponding parts of the single-layered structure part. The dummy patterns 5 are the patterns having 5mum width and having a photoresist on the surface and are formed to the extent that copper foil is dissipated in the stage of 2/3 the etching stage by etching from a lateral direction on progressing of the etching from the side faces as the etching progresses in spite of the presence of the photoresist on the surface. The normal patterns corresponding to the wiring patterns are formed on the mask base material 1 of the mask for the flexible circuit board at the point of the time 2/3 the etching stage ends. |
