Process of manufacturing a perpendicular magnetic pole structure

For PMR (Perpendicular Magnetic Recording) design, one of the major technology problems is the use of CMP to fabricate the pole structure. If the device is under-polished there is a danger of leaving behind a magnetic shorting layer while if it is over-polished there may be damage to the main pole. This problem has been overcome by surrounding the main pole, write gap, stitched write head pillar with a layer of CMP etch stop material which, using optical inspection alone, allows CMP (performed under a first set of conditions) to be terminated just as the stitched write head gets exposed. This is followed by a second CMP step (performed under a second set of conditions) for further fine trimming of the stitched head, as needed.