| 摘要 |
PURPOSE:To exactly define the end point of etching in the stage of forming through-holes to a coil conductor insulating layer and to exactly define the zero position of a gap depth by providing a thin metallic layer under the coil conductor insulating layer and etching the two-layered films consisting of the thin metallic layer and the coil conductor insulating layer at one time. CONSTITUTION:The thin metallic layer 4 defines the zero position of the gap depth and is provided for detecting the end point of etching in the stage of forming the through-holes of a gap forming part 8 and junction 9 of upper and lower magnetic layers by etching the 2nd insulating layer 5. Said layer consists of the 3-layered films of copper (Cu), gold (Au) or chromium (Cr) and nichrome (NiCr), etc., or Cr/Cu/Cr, Cr/Au/Cr, etc., by forming the same as adhesive layers. More specifically, the through-holes are formed by etching the 2nd insulating layer 5 and the thin metallic layer 4 thereunder at one time. The formation thereof ends when the etching of the thin metallic layer 4 ends. The thin metallic layer 4 is of the material which permits easy discrimination of the presence or absence thereof by visual observation. The end point is thus surely discriminated.
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