Thin film magnetic disc and method of manufacturing the disc

A thin film magnetic disc comprising:

• a nonmagnetic substrate;
• a magnetic layer formed on said nonmagnetic substrate;
• a protective layer formed on said magnetic layer;
• scattered bumps made of a material different in physical characteristics from that of said protective layer, which are formed integrally with said protective layer in such a manner as to project from the surface of said protective layer;
• and
• a lubricant layer formed on surfaces of said protective layer and said scattered bumps,
• wherein said protective layer is formed of a DLC layer, said DLC layer being made of either CVD carbon having a composite elastic coefficient of from 200 to 300 Gpa and a Raman intensity ratio, determined by separating a spectrum measured by Raman spectroscope into two peaks by a Gaussian method and taking the intensity ratio between the main peak near 1580 cm.sup.-1 and the peak near 1380 cm.sup.-1 as the Raman intensity ratio, of from 0.3 to 0.7 or sputtered carbon containing nitrogen in an amount of from 10 to 35 atomic %;
• and
• said scattered bumps are formed of a DLC layer, said DLC layer being made of either sputtered carbon having a composite elastic coefficient of from 80 to 120 Gpa and a Raman intensity ratio of from 0.9 to 1.5 or sputtered carbon containing hydrogen in an amount of from 10 to 35 atomic %.

A thin film magnetic disc comprising:

• a nonmagnetic substrate;
• a magnetic layer formed on said nonmagnetic substrate;
• a protective layer formed on said magnetic layer;
• scattered bumps made of a material different in physical characteristics from that of said protective layer, which are formed integrally with said protective layer in such a manner as to project from the surface of said protective layer;
• and
• a lubricant layer formed on surfaces of said protective layer and said scattered bumps,
• wherein a ratio of the surface area of said scattered bumps to the total surface area of said protective layer and said scattered bumps is less than 25% in a data zone of said disc;
• and the ratio is larger in the contact start-stop zone of said disc than that in the data zone.

A method of manufacturing a thin film magnetic disc including a nonmagnetic substrate, a magnetic layer formed on said nonmagnetic substrate and a protective layer formed on said magnetic layer, comprising the steps of:

• forming said magnetic layer on said nonmagnetic substrate;
• forming said protective layer on said magnetic layer;
• forming a scattered bump forming layer made of a material different from that of said protective layer on said magnetic layer;
• adhering particles scatteredly on said scattered bump forming layer and etching said scattered bump forming layer, using said particles as a mask, to a thickness reaching the surface of said protective layer to form scattered bumps;
• removing said particles used as the mask;
• and
• applying a lubricant on the surfaces of said protective layer and said scattered bumps.

A method of manufacturing a thin film magnetic disc including a nonmagnetic substrate, a magnetic layer formed on said nonmagnetic substrate and a protective layer formed on said magnetic layer, comprising the steps of:

• forming said magnetic layer on said nonmagnetic substrate;
• forming a scattered bump forming layer made of material different from that of said protective layer on said magnetic layer;
• adhering particles scatteredly on said scattered bump forming layer and etching said scattered bump forming layer, using said particles as a mask, to a thickness reaching the surface of said magnetic layer to form scattered bumps;
• forming said protective layer on the surface, except for said scattered bumps, of said magnetic layer
• removing said particles used as the mask;
• and
• applying a lubricant on the surface of said protective layer and said scattered bumps.

A method of manufacturing a thin film magnetic disc including a nonmagnetic substrate, a magnetic layer formed on said nonmagnetic substrate and a protective layer formed on said magnetic layer, comprising the steps of:

• forming said magnetic layer on said nonmagnetic substrate;
• forming a scattered bump forming layer made of a material different from that of said protective layer on said magnetic layer;
• adhering particles scatteredly on said scattered bump forming layer and etching said scattered bump forming layer using said particles as a mask, to a thickness halfway to said magnetic layer to form scattered bumps;
• forming said protective layer on the surface except for said scattered bumps, of said scattered bump layer etched;
• removing said particles used as the mask;
• and
• applying a lubricant on the surfaces of said protective layer and said scattered bumps.