As the read capabilities of magnetic disk systems improve due to advanced GMR heads, it becomes necessary to correspondingly reduce the area of recorded data. This requires a narrowing of the stitched sub-pole at the write gap. This has proved difficult for pole widths less than about 0.4 microns because of problems in filling the mold. In the present invention this is overcome by introducing a layer of PMGI (polydimethylglutarimide) between the planarized positive photoresist layer that comprises the mold and the non-magnetic write gap layer on which the mold rests. This greatly facilitates formation of a high aspect ratio hole with a clean flat bottom and essentially vertical sides as well as the subsequent removal of the photoresist after said hole has been filled through electroplating to form a stitched sub-pole.