Focus ion beam processing is widely using technological operation for creation different profiles from circuit editing and transmission electron microscopy sample preparation to microstructure analysis and prototype nanomachining.

         Most of problems connected with application of this instrument are accumulated in [1]. Meanwhile we met an interesting extra details connected with process of single crystal silicon (wafers) etching. In case of preparation of cylindrical holes the walls of this holes may be or smooth or contain periodically distributed ring-type surface asperities surrounded cylinder and located on equal distance one to another from the very beginning of this cylinder up to the bottom of it. The real situation is very dependent on the conditions of irradiation density of beam, scanning or stable beam used, frequency of scanning.

         Increasing of beam density leads to the formation of periodical relief on the walls surface. Under the scanning regime the decreasing of scanning frequency leads to disappearance of periodical relief. In the case of stable beam (no scanning) the formation of this periodical structure demonstrate non monotonous character. Relief appears and then disappears during the process of irradiation.

         Experimental work was carried out using standard FEI Quanta 200 3D set with parameters of beam: E= 5÷30 keV, I = 1÷20 nA, d ~ 2,75 μ

         Observed phenomena explained on the base of possibility of viscous flow under irradiation by ion beam with high density.

1. C.A.Volkert and A.M.Minor. Focused ion beam microscopy and micromachining. MRS Bulletin. 32 (2007) 389.

Aleksandr Chamov, JSC Mikron, Zelenograd, Moscow 124498, Russian Federation
Nikolai Gerasimenko*, Moscow Institute of Electronic Technology, Zelenograd, Moscow 124498, Russian Federation
Vitaly Khanin, JSC Mikron, Zelenograd, Moscow 124498, Russian Federation
Nurlan Medetov, Moscow Institute of Electronic Technology, Zelenograd, Moscow 124498, Russian Federation

*presenting author