PMR with improved writability and process controllability by double layer patterning

Abstract

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.

1 . A main pole layer having a write pole with two ends and two sides that terminates at a pole tip at an ABS plane on one end and adjoins a yoke at a neck position at an end opposite the ABS plane, said two sides have sidewalls with a bevel angle, and said yoke has sidewalls with an essentially vertical slope wherein said main pole layer is formed within an insulation layer that adjoins the sidewalls of the yoke and pole. 
     
     
         2 . The main pole layer of  claim 1  wherein said bevel angle is between about 5 degrees and 20 degrees. 
     
     
         3 . The main pole layer of  claim 1  wherein the main pole layer has a negative differential bevel angle (dBA) wherein the write pole sidewalls have a slope that is shallower than the essentially vertical slope of the yoke sidewalls. 
     
     
         4 . The main pole layer of  claim 1  wherein said insulation layer is comprised of alumina, silicon oxide, or another dielectric material. 
     
     
         5 . The main pole layer of  claim 1  wherein the write pole and yoke are comprised of CoFe, CoNiFe, or NiFe and have a thickness between about 0.1 and 10 microns. 
     
     
         6 . The main pole layer of  claim 1  further comprised of a top surface that is planar.