Determination of cross-link density in ion-irradiated polystyrene surfaces from rippling

The irradiation of polymer surfaces with ion beams leads to pronounced chemical and physical modifications when the ions are scattered at the atoms in the polymer chain. In this way, different products of decomposition occur. Here we show that by changing the ion fluence and the mass of the ion the local mechanical properties as Young’s modulus of a polystyrene surface layer can be tailored. By annealing prestretched irradiated PS near the glass transition, surface rippling occurs in the irradiated areas only, which can be described with an elastic model. The moduli obtained from rippling periodicities and elastic model assumptions are in the range between 8 and 800 MPa at the glass transition and characterize the irradiated PS as rubberlike. From these values the network density and the molar mass of entanglement are quantified. The obtained network density equals the density of hydrogen vacancies generated through the scattered ions, as confirmed by simulations of the atomic scattering and displacement processes. The obtained molar mass of entanglement reveals that the PS locally was densely cross-linked. Our results show that even for nondiscrete layered polymer systems relevant polymer parameters can be derived from the well-known surface rippling without the need for costly chemical analysis

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

Nanopatterning of magnetic disks by single-step Ar+ Ion projection

Large-area Ar+ projection has been used to generate planar magnetic nanostructures on a 1¿-format hard disk in a single step (see Figure). The recording pattern was transferred to a Co/Pt multilayer without resist processes or any other contact to the delicate media surface. It is conceivable that magnetic nanostructures can be replicated from a single stencil mask on large quantities of disks for future high-density recording

Entwicklung und Erprobung einer Maskentechnologie fuer die verkleinernde Ionenprojektion zur Herstellung von Strukturen im Bereich von 100 nm Abschlussbericht

Using the ion projector IPLM 01-2 (IMS, Wien), 100 nm structures for ion projection lithography could be obtained. Resolution and optical properties of the projector were characterized and optimized for device exposure. A new alignment system is based on particle detection during electrostatic scanning of the search beam via adjusting marks. Masks were produced by X-ray lithography and dry etching of Si mask blanks with reactive gases. In 2 #mu#m membranes openings of 1 #mu#m could be etched. The suitability of different lacquers as resits were tested. As test device a surface wave filter was constructed and characterized. The components developed in this project are the basis for future scaling down to the 50 nm region. (WEN)SIGLEAvailable from TIB Hannover: F94B15 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekBundesministerium fuer Forschung und Technologie (BMFT), Bonn (Germany)DEGerman

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+ at a 4 × demagnification. In a second experiment, sub-100-nm magnetic islands were produced using projection at 8.7 × demagnification and visualized by magnetic force microscopy

Large-Field Ion-Optics for Projection and Proximity Printing and for Mask-Less 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 Ion-Optics for Projection and Proximity Printing and for Mask-Less 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)