Method for manufacturing a magnetic hard disk having concentric magnetic tracks with flat surface

A method for fabricating a magnetic hard disk rotatable around a center of the disk having a plurality of magnetic tracks concentrically disposed around the center of the disk and spaced to each other, comprising the steps of:

• forming photoresist patterns concentrically arranged around a center of a substrate disk on a flat upper surface of a disk substrate such that width and space of the photoresist patterns corresponds to space and width of the magnetic tracks, respectively;
• depositing a first non-magnetic film, a magnetic film, a second non-magnetic film successively on the disk substrate having the photoresist patterns in the perpendicular direction to the substrate by sputtering method;
• removing the photoresist patterns together with deposited films thereon by lift-off method such that deposited films on the flat upper surface of the disk substrate are left;
• depositing a third non-magnetic film isotropically over the disk substrate such that a lowermost portion of an upper surface of the third non-magnetic film exceeds an uppermost portion of an upper surface of the second non-magnetic film;
• planarizing the third non-magnetic film by chemical mechanical polishing method until the upper surface of the second non-magnetic film is exposed such that the planarized surface has surface roughness smaller than 3 nm;
• depositing a fourth non-magnetic film all over the planarized surface;
• and
• roughening an upper surface of the fourth non-magnetic film by another polishing method such that the upper surface has roughness greater than 0.5 nm maintaining the surface roughness smaller than 3 nm inherited from the surface roughness of the planarized surface.