Thin Film Recording Heads

Fig. 1. Praxair MRC has developed special manufacturing technogy to control the permeability of CoPt-based alloys. Low permeability alloys having high MLF are offered, which retain MLF even after bonding to a backing plate.

The revolutionary advances in recording head technology are enabling 60% increases in the areal density on an annual basis. The advent and commercialization of devices based on Magnetoresisitve (MR), Giant Magnetoresistive (GMR), Tunneling Magnetoresistance (TMR) are requiring a wide variety of ferromagnetic, antiferromagnetic, non-magnetic target materials. Thin films are deposited from these targets using physical vapor deposition(PVD) or ion beam deposition (IBD) processes to manufacture these devices. The OEMs for these PVD and IBD tools, include, CVC, Veeco, Nordiko, CSC, Balzers and others. Praxair MRC offers targets for all of the major PVD and IBD tool manufacturers for recording head manufacturing.

Ferromagnetic target materials of interest to recording head manufacturers include, but not limited to, are: NiFe, CoFe, CoPt, CoCrPt, CoZrTa, CoNb, CoZrNb, Fe, FeAl, FeTa, FeZr, and FeAlSi. MRC has recognized that for magnetron sputtering, target fabrication processes must ensure uniformity of Magnetic Leakage Flux within a target and consistency of MLF values from target to target. We measure MLF using ASTM guidelines and can provide SPC data on MLF for your targets in production.

Fig. 2. A wide range of cobalt -based alloys have been invstigated for shield and pole layer applications. A plot showing the inerdepnedendece of MLF, target thcikness and permeability for whole rang eof alloys are provided. Data for alloy composition of interest may either be availble or can be measured.
The control of metallic and non-metallic impurities as well as grain size is common to both ferromagnetic and non-magnetic targets. Praxair MRC has successfully met the challenge to provide shield alloy targets which generate significantly lower particles, by controlling the interstitial contents. The use of pure Al target for reactive sputtering to Al2O3, copper, tantalum, and gold layers in MR/GMR/TMR structures require fully dense, fine grain size and high purity targets, which Praxair MRC has been providing.

Antiferromagnetic materials (AFM's) such as NiMn, PtMn, PdPtMn, and IrMn, are an important class of materials needed for the GMR recording heads. Praxair MRC has an active development program to address all key issues of concern to our customers, including controlling composition, oxygen content, recycling / reclaiming Pt, and target performance.

Thin Film Magnetic Media
Optical Recording Media