| 摘要 |
A non-magnetic gap layer is formed on a lower magnetic core layer. A magnetic layer for an upper magnetic pole piece as well as a non-magnetic cap layer is sequentially formed on the non-magnetic gap layer. A lower magnetic pole piece is shaped out of the lower magnetic core layer by employing the upper magnetic pole piece as a mask. A non-magnetic insulating layer is then formed all over the surface of the lower magnetic core layer. The non-magnetic cap layer is completely covered with the non-magnetic insulating layer. The non-magnetic insulating layer is then subjected to a flattening polishing process until the non-magnetic cap layer is exposed. The exposed non-magnetic cap layer is removed to expose the upper magnetic pole piece. The upper magnetic pole piece suffers from no abrasion in the flattening polishing process, so that the thickness of a narrower auxiliary upper magnetic pole can be set at a predetermined thickness at a higher accuracy.
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