Hubert Grimm

Ion projection direct structuring for patterning of magnetic media

Ion projection facilitates a direct structuring, which is an attractive potential manufacturing process for patterned storage media. An advantage to this method is that the media roughness remains unchanged. The feasibility of ion projection direct structuring for processing full disk surfaces was investigated using a next generation lithography projector. Co-Pt multilayer films with strong perpendicular anisotropy were deposited on 1-in glass disks as used in the IBM microdrive and on Si substrates. Concentric tracks including data, as well as head positioning servo structures, were patterned in a single exposure step with 45 keV He/sup +/ at a 4 /spl times/ demagnification. In a second experiment, sub-100-nm magnetic islands were produced using projection at 8.7 /spl times/ demagnification and visualized by magnetic force microscopy.

Large-field ion optics for projection and proximity printing and for maskless lithography (ML2)

Recent studies carried out with Infineon Technologies have shown the utility of Ion Projection Lithography (IPL) for the manufacturing of integrated circuits. In cooperation with IBM Storage Technology Division the patterning of magnetic films by resist-less Ion Projection Direct Structuring (IPDS) has been demonstrated. With masked ion beam proximity techniques unique capabilities for lithography on non-planar (curved) surfaces are outlined. Designs are presented for a masked ion beam proximity lithography (MIBPL) exposure tool with sub - 20 nm resolution capability within 88 mmo exposure fields. The possibility of extremely high reduction ratios (200:1) for high-volume ion projection mask-less lithography (IP-ML2) is discussed.

Large-field particle beam optics for projection and proximity printing and for maskless lithography

Recent studies have shown the utility of ion projection lithography (IPL) for the manufacturing of integrated circuits. In addition, ion projection direct structuring (IPDS) can be used for resistless, noncontact modification of materials. In cooperation with IBM Storage Technology Division, ion projection patterning of magnetic media layers has been demonstrated. With masked ion beam proximity techniques, unique capabilities for lithography on nonplanar (curved) surfaces are outlined. Designs are presented for a masked ion beam proximity lithography (MIBL) and masked ion beam direct structuring (MIBS) tool with sub-20-nm resolution capability within 88-mm□ exposure fields. The possibility of extremely high reduction ratios (200:1) for high-volume projection maskless lithography (projection-ML2) is discussed. In the case of projection-ML2 there are advantages of using electrons instead of ions. Including gray scaling, an improved concept for a ⩽50-nm projection-ML2 system is presented with the potential to meet a throughput of 20 wafers per hour (300 mm).

Evaluation of ion projection using heavy ions suitable for resistless patterning of thin magnetic films

The ion projector at the Fraunhofer Institute ISiT has been used for the development of patterned magnetic media for potential future use in magnetic hard disk drives. By 8.8 times demagnification of an open stencil mask, magnetic contrast is generated by ion intermixing of Co/Pt sandwich layers. In this application a resist process is not necessary and the surface roughness of magnetic media is not altered. Monte Carlo simulations of the intermixing process with the dynamic T-Dyn software for H, He, Ne, Ar and Au ions show that the exposure dose can be reduced by a factor of 100 by irradiation with Ar+ ions instead of He+. This has been confirmed by magnetic force microscopy of 200 nm magnetic dots irradiated at a dose of 6×1013 Ar+/cm2 at 73 keV energy. Sufficient stability of the ion optical system concerning resolution and drift has been demonstrated by exposures in developed and undeveloped (latent image) resist down to 60 nm dots.

Influence of magnetic properties of shields on recording head instability parameters

We report on the origin and the influence of small variations in magnetic properties of magnetically soft Sendust films, used as a bottom shield in magnetoresistive heads, on instability parameters probed by quasi-static measurements. A strong correlation of the shields magnetic characteristics with the average wafer asymmetry range is found. The variations in magnetic properties are directly connected with local anisotropy effects as revealed by Kerr microscopy. A direct correlation of the domain structures at the shields surface with microstructure of the film is found. The magnetic domains display a change of magnetics with film growth. The deviations of magnetic properties are due to small structural Sendust changes.

Influence of weak magnetic out-of-plane anisotropy in magnetic shields on recording head instability parameters

In this paper, we report on the origin and the influence of small changes in magnetic properties of magnetically soft Sendust films, used as a bottom shield, on instability parameters derived from quasi-static measurements.