Seagate Technology Incorporated

Jeff Duane St John

Connie C Liu

Linda Lijun Zhong

Shawn A Mawla

Qixu David Chen

Chung Yuang Shih

Samuel Dacke Harkness

Yuanda Randy Cheng

Jeffery Lee Petrehn

Jeff A Railton

Jeffrey Lee Petrehn

Roger Rostron Wills

Abnormal nodule formation during electroless plating, e.g., of amorphous NiP &ldquo;seed&rdquo; layers utilized in the manufacture of magnetic recording media, is eliminated or substantially reduced by performing the electroless plating process in an apparatus employing polymeric or polymer-based materials which are substantially resistant to degradation upon prolonged contact with the electroless plating bath at an elevated temperature, i.e., release of soluble, low molecular weight, carbon-containing species which are incorporated in the electroless plating deposit and act as nucleation centers for abnormal growth leading to nodule formation. Suitable degradation-resistant polymeric materials for use as fittings, piping, racks, tanks, etc. of the electroless plating apparatus include fluorine-containing hydrocarbons and fluorocarbons.

Nodule-free electroless nip plating

Surface processing of metal, such as CMP, is enhanced and defects reduced by pretreatment to remove a surface layer exhibiting properties different from the bulk metal, such as a baked on oxide layer. Embodiments of the present invention include acid soaking a non-magnetic substrate having an Al, Ni or Ni&mdash;P surface with a baked oxide film thereon, thereby removing the oxide film and rendering the reduced surface amenable to CMP with reduced defects, reduced surface roughness and increased production throughput.

Pretreatment for reducing surface treatments defects

High areal density magnetic recording media exhibiting low noise are formed with a Ni&mdash;P&mdash;X plating layer, in which X is an additive meeting the following requirement: (1) The additive has a higher oxidation potential than that of Ni so that grains of an additive-rich-oxide will form first during oxidation under a controlled atmosphere and grains of a Ni-rich-oxide, if any, will form subsequently and separately from the grains of the additive-rich oxide. (2) The additive has a tendency to segregate to the top surface. (3) The additive is not a catalyst poison for Ni&mdash;P plating in the composition range.

Control of magnetic film grain structure by modifying Ni-P plating of the substrate

Electrolessly plated Ni&mdash;P amorphous coatings having an increased magnetic transformation temperature and ultra smooth surface are achieved employing a plating bath containing Al and/or Cu ions. Embodiments include electrolessly depositing an amorphous Ni&mdash;P coating exhibiting a magnetic transformation temperature of at least 330&deg; C. proximate a laser textured protrusion.

Electroless nickel-phosphorous coatings with high thermal stability

Magnetic recording media including an alternative substrate material having a Young's Modulus greater than that of Al-based substrate materials and a preselected average surface roughness (Ra) are formed by depositing a continuous, adherent, non-magnetic, catalytically active layer on a surface of the substrate and electrolessly plating an amorphous seed layer on the catalytically active layer, the Ra of the resultant surface of the amorphous seed layer being reduced from that of the substrate, thereby providing a substantially defect-free surface for deposition thereon of magnetic recording media layers thereon. Embodiments include sputter depositing an catalytically active layer of Ni&mdash;Al or Ni&mdash;P and electrolessly plating an amorphous seed layer of Ni&mdash;P thereon.

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Los Gatos, CA, United States of America

Jeff Duane St John