| 摘要 |
PURPOSE:To attain forming with high efficiency by applying ultrasonic wave vibration to an etching liquid at the process of etching of a hole exposing a magnetic core to a face opposite to a recording medium. CONSTITUTION:First a blank body 4 is formed to form a fitting hole 11 and a holding hole 12. A shield plate 5 is assembled after heat treatment and resist is coated. Then the plate is baked to form a resist pattern and then the pattern is etched. The hole 7 is completed by removing the resist. The processing efficiency is improved by applying processing while the etching liquid is vibrated in the ultrasonic wave in the etching processing during the process of manufacture, and the processing time is reduced. Since the hole 7 is processed, no processing deteriorating layer exists in the hole 7, the permeability of a substantial magnetic substance is obtained, the shield effect is improved and the leakage magnetic flux is reduced. |
