PMR with improved writability and process controllability by double layer patterning

摘要

Improved writability and a sharper neck transition are achieved in a PMR writer with a yoke that has essentially vertical sidewalls and a write pole that has sidewalls with a beveled angle. An alumina mold is made with a negative differential bevel angle by employing a two mask process. A first photoresist layer is patterned and etched to form a rectangular trench in an alumina layer. The trench extends beyond the intended ABS plane and in the opposite direction into the intended yoke area. A second photoresist layer is patterned into a yoke shape that is partially superimposed over the rectangular trench. After a second RIE process, the yoke opening adjoins the trench at a neck transition point along each long trench side. The volume of magnetic material in the yoke adjacent to the neck is thereby maximized. Dimension control of the main pole becomes independent of ABS positioning errors.