| 摘要 |
PURPOSE:To easily and accurately confirm the time of end by alternately laminating two kinds of metallic plate layers having different colors to a terminal pad and deciding the grinding end time of a protection film by the color layer change of a terminal pad. CONSTITUTION:After forming an electromagnetic conversion part 12 on a substrate 11, a connecting terminal pad 31 is formed on a pad formation predetermined area through a conductor film 19 for plating by mask plating method. At that time, the pad 31 is formed by alternately laminating eight layers of at least two kinds of plating layers having different colors, e.g., 4mum Cu plating layer 31a and 1mum Ni plating layer 31b. In case of grinding the film thickness d1 of the protection film 23 up to 10mum or more, the end time of grinding work is decided by the color layer change of the plating layers of the pad 31 by using an optical microscope. Consequently, the end time can be easily and accurately detected. |
