Enhancement of cover-layer surface properties using dielectric protective layer

유전체 보호층을 이용한 NFR 미디어 커버층의 표면 특성 향상

Scratches are observed on a polymer cover-layer of near-field recording (NFR) media after a servo test with rotating disc. The scratches are formed by the collision of a solid immersion lens (SIL)-media. One of the possible ways to avoid the scratch problem is to coat a dielectric protective film on the polymer cover-layer which enhances the hardness of the surface. The surface with hard characteristics in the surface reduces the scratch problem in the cover-layer. Not only the mechanical properties but also the optical properties should be controlled. Specifically, the refractive index of the dielectric protective film should be matched with the polymer cover-layer not to lose light at the interface due to the difference of the refractive index. The refractive index of the dielectric film can be tailored by controlling process parameters during sputtering and matched with that of the polymer cover-layer.