Systems and methods for correcting read/write overlay errors in the manufacture of magnetic transducers for storage drives

Abstract

Systems and methods for correcting read/write overlay errors in the manufacture of magnetic transducers for storage drives are provided. One such system includes a twisting tool configured to receive and secure a row bar having an elongated rectangular block shape and including a plurality of magnetic transducers spaced apart along a length of the row bar, and where the twisting tool is configured to twist the row bar at a plurality of areas along the length of the row bar.

What is claimed is: 
     
         1 . A method for correcting for overlay errors in row bars, the method comprising:
 measuring an overlay error at preselected positions along a length of the row bar, wherein the row bar comprises an elongated rectangular block shape and a plurality of magnetic transducers spaced apart along the length of the row bar, wherein the overlay error is indicative of a variation from a parallel orientation of a reader layer and a writer layer of at least one of the plurality of magnetic transducers;   twisting the row bar to substantially correct the overlay error; and   lapping the row bar to substantially correct the overlay error.   
     
     
         2 . The method of  claim 1 , wherein the twisting the row bar to substantially correct the overlay error comprises attaching the row bar to a twisting tool. 
     
     
         3 . The method of  claim 2 :
 wherein the row bar comprises an electronic lap guide (ELG); and   wherein the attaching the row bar to the twisting tool further comprising wire bonding to at least one terminal of the ELG.   
     
     
         4 . The method of  claim 1 :
 wherein the row bar comprises an electronic lap guide (ELG);   wherein the ELG is configured to provide information indicative of a measurement of a dimension of the row bar;   wherein the twisting the row bar to substantially correct the overlay error comprises twisting the row bar by a preselected degree based on the ELG measurement information; and   wherein the lapping the row bar to substantially correct the overlay error comprises lapping the row bar by a preselected degree based on the ELG measurement information.   
     
     
         5 . The method of  claim 1 :
 wherein the twisting the row bar to substantially correct the overlay error comprises twisting the row bar at the preselected positions having the overlay error.   
     
     
         6 . The method of  claim 1 :
 wherein the lapping the row bar to substantially correct the overlay error comprises lapping the row bar at the preselected positions having the overlay error.   
     
     
         7 . The method of  claim 1 :
 wherein the twisting the row bar to substantially correct the overlay error comprises twisting the row bar by a preselected degree based on the measured overlay error; and   wherein the lapping the row bar to substantially correct the overlay error comprises lapping the row bar by a preselected degree based on the measured overlay error.   
     
     
         8 . The method of  claim 1 :
 wherein the twisting the row bar to substantially correct the overlay error comprises twisting the row bar using a twisting tool configured to twist the row bar at a plurality of areas along the length of the row bar.   
     
     
         9 . The method of  claim 8 , wherein the twisting tool comprises a plurality of planar twisting segments each configured to impart a twisting force on the row bar. 
     
     
         10 . The method of  claim 8 , wherein the twisting tool comprises a plurality of planar twisting segments in each of the plurality of areas, wherein each of the plurality of planar twisting segments is configured to impart a twisting force on the row bar. 
     
     
         11 . The method of  claim 10 , wherein the twisting tool further comprises a force applicator configured to impart a force on each of the plurality of planar twisting segments in one of the plurality of areas, wherein the force applicator comprises a set screw apparatus. 
     
     
         12 . The method of  claim 1 , wherein the twisting the row bar to substantially correct the overlay error comprises twisting the row bar about a longitudinal axis of the row bar. 
     
     
         13 . The method of  claim 12 , wherein the twisting the row bar about a longitudinal axis of the row bar comprises imparting a twisting force on the row bar sufficient to rotate a portion of the row bar about the longitudinal axis. 
     
     
         14 . The method of  claim 12 :
 wherein the twisting the row bar about a longitudinal axis of the row bar comprises twisting the row bar using a twisting tool;   wherein the twisting tool comprises a first planar twisting segment and a second planar twisting segment, wherein the first planar twisting segment and the second planar twisting segment are configured to receive and secure the row bar; and   wherein the method further comprises:
 imparting, using the first planar twisting segment, a twisting force on the row bar sufficient to rotate a portion of the row bar about the longitudinal axis; and 
 opposing, using the second planar twisting segment, the twisting force. 
   
     
     
         15 . The method of  claim 1 :
 wherein the twisting the row bar to substantially correct the overlay error comprises twisting the row bar about a longitudinal axis of the row bar using a twisting tool;   wherein the twisting tool comprises a force applicator, a first planar twisting segment, and a second planar twisting segment, wherein the first planar twisting segment and the second planar twisting segment are configured to receive and secure the row bar, wherein the first planar twisting segment is proximal and the second planar twisting segment is distal relative to an end of the row bar;   wherein the force applicator is configured to impart a rotational force on the first planar twisting segment and thereby cause the first planar twisting segment to impart a twisting force on the row bar sufficient to rotate a portion of the row bar about the longitudinal axis; and   wherein the second planar twisting segment is configured to oppose the twisting force.   
     
     
         16 . The method of  claim 1 , wherein the twisting the row bar to substantially correct the overlay error comprises:
 imparting, at a first location along the row bar, a twisting force sufficient to rotate a portion of the row bar about a longitudinal axis of the row bar; and   opposing, at a second location along the row bar spaced apart from the first location, the twisting force.