Lithography with high depth of focus by an ion projection system

Ion projection lithography has been developed to generate structures with minimum feature sizes in the 100 nm range with a high pixel transfer rate. The high depth of focus resulting from the telecentric beam path concept is noteworthy as well. A silicon wafer exhibiting 200 Mym deep cavities which were fabricated by anisotropic etching was patterned with a grating of 0.6 Mym periodicity running with identical spacings from the bottom to the top. SiOsub2 served as an inorganic ion sensitive resist. Exposed to 73 KeV helium ions, SiOsub2 showed an enhanced etching rate in hydrofluoric acid, the structure developing agent. The application of patterning techniques considered here would be promising for the fabrication of twodimensional reflecting mirrors or sensoric elements distributed on spherical surfaces.