SURFACE INTERACTIONS DURING NANOSCALE PATTERNING OF ADVANCED ELECTRONIC MATERIALS USING PLASMA

Photolithographic patterning of photoresist materials and transfer of these images into electronic materials using directional plasma etching techniques plays a critical role in the fabrication of integrated circuits. As critical device dimensions are reduced below 100 nm, precise control of the interactions of process plasmas with materials is required for successful integration. This requires a scientific understanding of plasma-surface interaction mechanisms that control the properties of the ultimate devices and ICs produced. Fluorocarbon discharges are commonly used for dielectric etching, e.g. SiO2. In this work we have studied surface-chemical aspects of the interaction of C4F8/Ar discharges with SiO2 and Si. Free fluorine atoms that are liberated from fluorocarbon species during ion bombardment are driven to the surface and react with the substrate, a process called defluorination. The defluorination is dependent on the plasma properties and the penetration of reactive species is limited within 10nm below the surface. Future device requires novel materials, i.e. nanoporous silica, to replace conventional SiO2.When some O atoms in Si-O matrix are replaced with nano cavities (pores), the plasma-induce