Shenzhen Kaifa Magnetic Recording Co.

Shenzhen, China

Shenzhen Kaifa Magnetic Recording Co.

Shenzhen, China
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Lei H.,University of Shanghai for Science and Technology | Chu F.,University of Shanghai for Science and Technology | Xiao B.,University of Shanghai for Science and Technology | Tu X.,Shenzhen Kaifa Magnetic Recording Co. | And 2 more authors.
Microelectronic Engineering | Year: 2010

A novel silica/ceria nano composite abrasive was synthesized by homogeneous precipitation using carbamide, ammonium ceric nitrate and silica. The abrasive was characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectroscopy (TOF-SIMS) and scanning electron microscopy (SEM), respectively. Then, the chemical mechanical polishing performances of the composite abrasive on hard disk substrate with nickel-phosphorous plated were investigated. Atomic force microscopy images show that the prepared abrasive gives much lower topographical variations than before polishing. The average waviness (Wa) of the polished hard substrate surface can be reduced from 15.5 before polishing to 8.36 , and the average of roughness (Ra) can be reduced from 14 before polishing to 4.80 . © 2009 Elsevier B.V. All rights reserved.


Lei H.,University of Shanghai for Science and Technology | Sima N.,Shenzhen Kaifa Magnetic Recording Co. | Tu X.-F.,Shenzhen Kaifa Magnetic Recording Co. | Bu N.-J.,University of Shanghai for Science and Technology | And 2 more authors.
Mocaxue Xuebao/Tribology | Year: 2010

A kind of novel silicon /ferric oxide core-shell abrasive was synthesized using HNO3, NaOH, Fe(NO3)3 and SiO2 by chemical co-precipitation, and its structure and dispersibility were characterized by X-ray diffraction (XRD), time-of-flight secondary ion mass spectroscopy (TOF-SIMS) and scanning electron microscope (SEM). The results showed that Fe2O3 were successfully coated on the surface of SiO2 particles, and the composite abrasive has good dispersibility. The CMP performances of the SiO2/Fe2O3 composite abrasive on hard disk substrate were investigated by UNIPOL-1502 CMP equipment. The average roughness of surface can be reduced from 8.87 nm to 3.73 nm after polishing for 7 minutes. Microscope images of polished surfaces indicated that the slurry containing SiO2/Fe2O3 composite abrasive exhibited improved CMP performances.


Lei H.,University of Shanghai for Science and Technology | Bu N.,University of Shanghai for Science and Technology | Chen R.,University of Shanghai for Science and Technology | Hao P.,University of Shanghai for Science and Technology | And 3 more authors.
Thin Solid Films | Year: 2010

α-Alumina-g-polystyrene sulfonic acid (α-Al2O3-g-PSS) composite abrasive was prepared by surface activation, graft polymerization and sulfonation, successively. The composition, dispersibility and morphology of the product were characterized by Fourier transformed infrared spectroscopy, laser particle size analysis and scanning electron microscopy, respectively. The chemical mechanical polishing (CMP) performances of the composite abrasive on hard disk substrate with nickel-phosphorous plating were investigated. The microscopy images of the polished surfaces show that α-Al2O3-g-PSS composite abrasive results in improved CMP and post-CMP cleaning performances than pure α-alumina abrasive under the same testing conditions. © 2010 Elsevier B.V. All rights reserved.


Qi Z.,Shenzhen Kaifa Magnetic Recording Co. | Lu W.,Shenzhen Kaifa Magnetic Recording Co. | Guo A.,Shenzhen Kaifa Magnetic Recording Co. | Hu Y.,Shenzhen Kaifa Magnetic Recording Co. | And 2 more authors.
Industrial and Engineering Chemistry Research | Year: 2014

In this study, a typical circular pit of electroless Ni-P coating has been investigated with atomic force microscopy (AFM), nanoindentation, and focused ion beam-scanning electron microscopy (FIB-SEM). It is found that the land area of the circular pit has lower hardness than the good surface, and there is a spherical-crown-shaped boundary between the pit and the coating. The formation mechanism of such defects is because the H2 gas bubble generated by the chemical reaction attaches to the plating surface and stops the Ni-P growth on such area, and after the bubble is released the Ni-P starts to grow again and forms a new germination phase. The computational fluid dynamics (CFD) simulations have found that the plating fluid with current plating carousel design has vortex flow around the disks and the H2 gas bubbles have a high possibility to attach to the disk surface. An optimized plating carousel design is proposed which can facilitate the release of H2 gas and reduce such circular pits. © 2014 American Chemical Society.


Qi Z.,Shenzhen Kaifa Magnetic Recording Co. | Lu W.,Shenzhen Kaifa Magnetic Recording Co. | Lee W.,Shenzhen Kaifa Magnetic Recording Co.
International Journal of Machine Tools and Manufacture | Year: 2014

Concentric and eccentric brush scrubbing behaviors of the hard disk drive (HDD) substrates in post-chemical mechanical polishing (CMP) process have been investigated with kinetic brush-disk contact trajectory analysis and hydrodynamic fluid velocity simulation as well as experimental studies. The adhesion forces as well as the hydrodynamic drag force for particle removal are also discussed. The brush nodules-disk contact trajectories with eccentric scrubbing cover the full surface of the disk, however, the trajectories with concentric scrubbing only accumulate on several concentric circular bands aligned along the discrete distribution of brush nodules. The fluid hydrodynamic force with eccentric scrubbing is larger than that with concentric scrubbing. The experimental results have found that the disk surfaces with eccentric scrubbing have approximately 40% lower particle count than that with concentric scrubbing. The modeling analysis and experimental results have found that the eccentric scrubbing has higher particle removal efficiency for the work piece with a hole at the center. © 2014 Elsevier Ltd.


Qi Z.,Shenzhen Kaifa Magnetic Recording Co. | Lee W.,Shenzhen Kaifa Magnetic Recording Co.
Tribology International | Year: 2010

Chemical mechanical polishing (CMP) mechanisms of NiP coating plated on Al-Mg alloy substrates have been investigated with an X-ray photoelectron spectroscope (XPS). The XPS results indicate that after cleaning, the disk surface contains a thin layer of Ni(OH)2 and P2O3, followed by a thin NiO and P2O3 layer. It is also deduced that during polishing, the disk surface has an oxidization layer with Ni2+ and P3+ species. The experimental investigations reveal that the CMP mechanisms involve a simultaneous process of surface chemical passivation and nano-particle wear. © 2009 Elsevier Ltd. All rights reserved.

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