Regensburg 2002 – scientific programme

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HL: Halbleiterphysik

HL 9: Optische Eigenschaften

HL 9.6: Talk

Monday, March 11, 2002, 16:45–17:00, H15

IR Spectroscopic Characterization of Thin Silicon Masks for the Ion Projection Litography — •Rados Gajic¹, Dieter Braun¹, Fiedemar Kuchar¹, Regina Korntner², Hans Löschner², Reinhard Springer³, Florian Letzkus³, and Jörg Butschke³ — ¹Montanuniversität Leoben, Franz Josef Strasse 18, A-8700 Leoben, Österreich — ²IMS Nanofabrication GmbH,Schreygasse 3,A-1020 Wien, Österreich — ³IMS-Chips, Institut für Mikroelektronik Stuttgart, Allmandring 30 a, D-70569 Stuttgart

The Ion Projection Lithography (IPL) is one among few promissing methods for the next generation lithography. Hydrogen or helium ions strike a patterned stencil Si mask producing its image on the photo resist of the wafer. The absorbed ions in the protective carbon layer heat the stencil mask. In order to avoid heat-induced distortions the vacuum placed mask must be cooled. As the heat conductivity is almost negligible of the 12 cm diameter large and 3 µm thick p-doped Si mask, the IR emission of the mask is a crucial factor for the cooling process. Therefore, the determination and the optimisation of the emissivity is of a prime importance for the success of the IPL project. We measured the FIR and MIR transmittance and reflectance spectra as a function of the Si mask radius. In order to extract the parameters of the mask, as are the effective mass m^*, the carrier relaxation time τ of holes, as well as the thickness of the Si and carbon layer, we used different fitting procedures based on the Drude model corrected to include the inter-valence scattering. As a result we calculated the emissivity. of the Si stencil masks.