METHOD OF MANUFACTURING A MASTER INFORMATION CARRIER FOR MAGNETIC TRANSFER AND A METHOD OF MANUFACTURING A MAGNETIC RECORDING MEDIUM
A method of easily manufacturing a master disk for magnetic transfer is disclosed. The method of the invention facilitates separation of the master disk and a slave disk to be transferred even after conducting a magnetic transfer process after adhering the two disks by pressing or exhaustion for the purpose of enhancing transfer performance. A method of manufacturing a master disk comprises a step of forming recesses by eliminating selected parts of a surface region of soft magnetic layer 20 that is uniformly formed on the surface of substrate 10 , to a depth not to cut apart the parts with one another, and a step of transforming recessed parts 20 b to a nonmagnetic or low magnetic state. The steps forms a pattern of protrusions 20 a and recesses 20 b corresponding to information to be magnetically transferred, the protrusions 20 a being magnetic and the recesses 20 b being nonmagnetic or low magnetic.
1 . A method of manufacturing a master information carrier for magnetic transfer comprising:
forming a soft magnetic layer uniformly on a surface of a substrate;
forming recesses by eliminating selected parts of a surface region of the soft magnetic layer to a depth less than the depth of the soft magnetic layer; and
transforming the recessed parts to nonmagnetic or low magnetic;
thereby producing a pattern of protrusions and recesses corresponding to information to be magnetically transferred, wherein the protrusions are magnetic and the recessed parts are nonmagnetic or low magnetic.
2 . The method of manufacturing a master information carrier for magnetic transfer according to claim 1 , wherein the soft magnetic layer is composed of a magnetic material comprising primarily FeCo.
3 . The method of manufacturing a master information carrier for magnetic transfer according to claim 1 , wherein the step of transforming the recessed parts to nonmagnetic or low magnetic is carried out by exposing the parts to a gas capable of degrading magnetic properties.
4 . The method of manufacturing a master information carrier for magnetic transfer according to claim 3 , wherein the gas capable of degrading magnetic properties is CF 4 gas and the step of transforming the recessed parts into nonmagnetic or low magnetic is carried out by a dry etching method using the CF 4 gas.
5 . A method of manufacturing a magnetic recording medium comprising:
adhering a master information carrier for magnetic transfer manufactured by the method as defined by claim 1 and a magnetic recording medium; and
applying a transferring magnetic field to the master information carrier to magnetically transfer the information corresponding to the pattern of protrusions and recesses thereon to the adhered magnetic recording medium.