Focused Ion Beam Based Three-Dimensional Nano-Machining

In recent days, the micro/nano machining becomes an important process to fabricate micro/nano scale dimensional patterns or devices for many applications, especially in electrical and electronic devices. There are two kinds micro-machining in use. i) bulk micromachining, ii) surface micro-maching. In the case of bulk micromaching, the structures can be made by etching inside a substrate selectively, however, in the case of surface micromachining; the patterns can be made on the top a desired substrate. FIB machining is considered as a one of famous bulk micro-machining processes. Many fabrication methods have been applied to fabricate the devices with smaller sizes (Kim, 1999; Latyshev, 1997). However, conventional until now the size of the smallest pattern was only 2×2 μm2 was achieved with a lithography technique (Odagawa et al., 1998). Three dimensional as an alternative approach, focused-ion-beam (FIB) etching technique is the best choice for the micro/nano scale patterning. FIB 3-D etching technology is now emerged as an attractive tool for precision lithography. And it is a well recognized technique for making nanoscale stacked-junction devices, nano-ribbons and graphene based 3-D Single Electron Transistor (SET) devices. FIB micro/nano machining is a direct etching process without the use of masking and process chemicals, and demonstrates sub-micrometer resolution. FIB etching equipments have shown potential for a variety of new applications, in the area of imaging and precision micromachining (Langford, 2001; Seliger, 1979). As a result, the FIB has recently become a popular candidate for fabricating high-quality micro-devices or high-precision microstructures (Melnagilis et al., 1998). For example, in a micro-electro-mechanical system (MEMS), this processing technique produces an ultra microscale structure from a simple sensor device, such as, the Josephson junction to micro-motors (Daniel et al., 1997). Also, the FIB processing enables precise cuts to be made with great flexibility for microand nanotechnology. Also, the method of fabricating three-dimensional (3-D) microand nanostructures on thin films and single crystals by FIB etching have been developed in order to fabricate the 3-D sensor structures (Kim, 2008, 1999).