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Articles you may be interested inFocused helium and neon ion beam induced etching for advanced extreme ultraviolet lithography mask repair Nanometer fabrication using selective thermal desorption of SiO 2 induced by focused electron beams and electron beam interference fringes This study investigates focused electron beam induced etching for the removal of alumina particles on patterned extreme ultra violet ͑EUV͒ mask using nitrosyl chloride ͑NOCl͒ as assist gas. As potential contaminant, particles of aluminum oxide ͑alumina, Al 2 O 3 ͒ have been successfully removed, leaving the underlying layers undamaged. Particles were applied onto an EUV mask, consisting of a multilayer Bragg mirror capped with a thin ruthenium layer and a structured tantalum nitride ͑TaN / TaON͒ absorber/antireflective film. Alumina particles were selectively etched using the chlorine-based gas, NOCl. Neither the Ru nor the absorber was significantly etched during the process in spite of a square area scanned by the focused electron beam being larger than the particle. The process resolution is discussed based on Monte Carlo electron scattering simulations. Thermodynamic driving forces for the electron-induced reactions and its selectivity are discussed and a chemical rationale is proposed.

The applicability of electron-beam induced chemical reactions to mask repair is investigated. To achieve deposition and chemical etching with a focused electron-beam system, it is required to disperse chemicals in a molecular beam to the area of interest with a well-defined amount of molecules and monolayers per second. For repair of opaque defects the precursor gas reacts with the absorber material of the mask and forms a volatile reaction product, which leaves the surface. In this way the surface atoms are removed layer by layer. For clear defect repair, additional material, which is light absorbing in the UV, is deposited onto the defect area. This material is rendered as a nanocrystalline deposit from metal containing precursors. An experimental electron-beam mask repair system has been developed and used to perform exploratory work applicable to photo mask, EUV mask, EPL, and LEEPL stencil mask repair. The tool is described and specific repair actions are demonstrated. Platinum deposited features with lateral dimensions down to 20 nm demonstrate the high resolution obtainable with electron beam induced processes, while AFM and AIMS measurements indicate, that specifications for mask repair at the 70 nm device node can be met. In addition, examples of etching quartz and TaN are given.