Research On Quality Improvement Of Magnetic Head's Surface Precision Lapping Process

The higher capacity and density of harddisk request better performance for reading-writing.Then it's necessary to improve the height-accuracy of reader and writer.The other side,better surface quality is helpful to get lower flight height.If rough peak is bigger than flight height,data damage or reading-writing function failure issue may happen for head crash.The head 's nanoscale height,surface roughness and profile are made by Resi stance Lapping Guidence to achieve reading-writing function in magnetic head manufacture process.If the raised black spot and height-accuracy can be improved by RLG process,the head 's performance,yield and reliability will be better.It will benefit the enterprise's competitiveness.This thesis anlyzed the magnetic head manuafcture flow and Resistance Lapping Guidence process firstly.Then this thesis researched on black spot and height control technology of reader and writer.Later,the reasons and fac tors of black spot and height control principle were discussed and analyzed.Black spot was caused by embedded diamond according the findings by element and lapping process analyzing.The factors to make black spot,included diamond structure and size,and plate material,and lapping press force,and diamond status on the plate,were verified by experiment.Then suitable process parameter and condition were found to improve black spot.One new method of floating diamond separating was provided and proofed b y experiment to improve black spot.The other side,this thesis analyzed height control methods and process,then made a point to improve reader height abnormal rate by rank lapping according sigma: when sigma is big,slow down plate speed to get longer la pping time,then PID control can converge better;when sigma is small,speed up the plate speed to get shorter lapping time.Angle dynamic feedback adjust method was provided to improve the abnormal rate for writer height control.Finally,the positive eff ects of both methods were verified by experiment after optimizing lapping control softerware and hardware.