Lithography focused ion beam

Figure 15.8 Schematicof three ways of employing ion beams in lithography (a) focused ion beam lithography, (b) proximity ion-beam lithography, (c) ion projection lithography.

Arshak, K., Mihov, M., Arshak, A., McDonagh, D., and D. Sutton. 2004. Novel dry-developed focused ion beam lithography scheme for nanostructure applications. Microelectronic Engineering 73-74 144—151. 

Glass, G. A., Rout, B., Dymnikov, A. D. et al. 2005. High energy focused ion beam lithography using P-beam writing. Nuclear Instruments and Methods in Physics Research B 241 397-401. 

Almost all polymers are more sensitive (require fewer exposure units) when exposed to ion beams than when they are exposed to e-beams. Polymers such as styrene and novolac, which are relatively insensitive to e-beams, have a much more sensitive response to ion beams. However, resist speed is important for focused ion beam lithography and several high speed resists have been found, Poly(2,2,2-trifluoroethyl a-chloroacrylate), a scissioning positive tone polymer, and two cross-linking negative tone polymers, poly(2,5-dichlorostyrene) and poly(4-bromostyrene), have been found to function at high speed as ion beam resists. ... 

As a consequence one might expect that the future needs to rely on hybrid elements which arise from advanced UV-and electron-beam lithography, from imprint techniques or automated and parallelized nanomanipulation techniques, like dip-pen lithography or focused ion-beam techniques in combination with supramolecular approaches for the assembly of molecular inorganic/organic hybrid system. Nevertheless, it is evident for any kind of chemical approach that falling back onto the present-day... 

There are three ways in which ion beams are employed in lithography (see Fig. 15.8). A point beam can be focused to a fine spot ( 10 nm) from a bright point source and deflected on the surface, in an arrangement called focused ion beam (FIB), to expose the resist directly without a mask. " Two types of ion sources, liquid metal and gaseous (cryogenic) field ion source, have been successfully used in this technology. Of these two sources, liquid metal has... 

MelngaiUs, AppUcations of ion microbeams in lithography and direct processing, Handbook of VLSI Microlithography, 2nd ed., J.N. Helbert, Ed., William Andrew Inc., pp. 790 855 (2001). Other applications of focused ion beam in integrated circuit industry include device repair, failure analysis, and direct implantation of ions into substrates. 

Kurihara, A focused ion beam system for submicron lithography, J. Vac. Set Technol. B 3, 41 (1985) E. Miyauchi, H. Hashimoto, and T. Utsumi, Lateral spreads of Be and Si in GaAs implanted with a maskless ion implantation system, Jpn. J. Appl. Phys. 22, L225 (1983) K. Gamo, T. Matsui, and S. Namba, Characteristics of Be Si Au ternary alloy liquid metal ion sources, Jpn. J. Appl. Phys. 22, L692 (1983). 

For single-nanowire devices, highly expensive techniques (such as a focused ion beam, or a series of nano-lithographic tools) must be used, ranging from proton and electron beam nanoUthography, in which patterned substrates are obtained under the application of a charged particle beam, to nano-imprint lithography. ... 

---