AVS 53rd International Symposium
    Nanometer-scale Science and Technology Wednesday Sessions
       Session NS+NM-WeA

Paper NS+NM-WeA9
High Resolution Electron Beam Induced Etching of Extreme Ultraviolet (EUV) Lithography Mask Films

Wednesday, November 15, 2006, 4:40 pm, Room 2016

Session: Nanolithography and Patterning
Presenter: M.G. Lassiter, University of Tennessee
Authors: M.G. Lassiter, University of Tennessee
P.D. Rack, University of Tennessee
T. Liang, Intel Corp.
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The application of EUV wavelengths for lithography is emerging as a viable technology to extend the production of small feature sizes for integrated circuits and nanotechnology. In order to make EUV lithography commercially viable, production of the mask requires the repair of defects found during the mask inspection. Traditionally, the highest resolution mask repair technology involves using a focused ion beam (FIB) of Gallium ions to physically sputter away material for etching and to induce dissociation of a precursor gas to deposit material for repairs. Some of the Gallium ions are implanted into the surface of the mask and leave undesirable effects such as reduced transmission of clear area repairs in photomasks and reduced reflection of the clear area of EUV masks. The use of electron beam induced processes for the repair of EUV masks has recently been developed as an alternative to FIB repair of masks. The electron beam induces the dissociation of a precursor gas to cause a reaction at the surface of the mask. This reaction either deposits material or causes the etching of the mask material, depending upon the type of precursor used and the substrate material. This work focuses on the latter case of electron beam induced etching (EBIE). Electron beam provides superior spatial resolution than that of the FIB, so the EBIE process can be more effective in small mask feature repairs. Also, the electron beam will not damage the mask materials because of the relatively small mass of the electron and relatively low energy used in the electron beam. This work characterizes the process of high resolution EBIE of Tantalum Nitride based EUV mask films. The effects of electron beam parameters such as accelerating voltage, beam current, and the scanning parameters are investigated. Furthermore, the use of various precursor gases is examined, and the effects on spatial resolution, etching rate, and selectivity against other materials are determined.