Focused Ion Beam instrument

TABLE 4.3 Installation Record for Focused Ion Beam Instruments Made by JEOL Semiconductor Equipment Division Instrument Number Customer ... 

FIGURE 4 A schematic representation of a focused ion beam instrument (adapted from Guiaimuzzi and Stevie 1999). 

L.A. Giannuzzi and F.A. Stevie, Introduction to Focused Ion Beams Instrumentation, Theory, Techniques and Practice (Springer, New York, 2005). 

Computers will be integrated more and more into commercial SEMs and there is an enormous potential for the growth of computer supported applications. At the same time, related instruments will be developed and extended, such as the scanning ion microscope, which uses liquid-metal ion sources to produce finely focused ion beams that can produce SEs and secondary ions for image generation. The contrast mechanisms that are exhibited in these instruments can provide new insights into materials analysis. 

In Dynamic Secondary Ion Ma s Spectrometry (SIMS), a focused ion beam is used to sputter material from a specific location on a solid surface in the form of neutral and ionized atoms and molecules. The ions are then accelerated into a mass spectrometer and separated according to their mass-to-charge ratios. Several kinds of mass spectrometers and instrument configurations are used, depending upon the type of materials analyzed and the desired results. 

A focused ion beam (FIB) can be used instead of a conventional ion mill to mill a sample. In such cases, especially targeted regions of a sample can be thinned for observation in the TEM. This technique requires expensive instrumentation but is becoming extremely popular in the age of VLSI devices and nanostructured components, where precise thinning of specific areas is necessary. 

In 1967 Liebl reported the development of the first imaging SIMS instrument based on the principle of focused ion beam scanning [24]. This instrument, the ion microprobe mass analyzer, was produced by Applied Research Laboratories (Fig. 4.5). It used an improved hollow cathode duoplasmatron [25] ion source that eliminated filaments used in earlier sources and allowed stable operation with reactive gases. The primary ion beam was mass analyzed for beam purity and focused in a two-lens column to a spot as small as 2 pm. The secondary ions were accelerated from the sample surface into a double focusing mass spectrometer of Mattauch-Herzog geometry. Both positive and negative secondary ions were de-... 

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. 

Sadoh, T., Eguchi, H., Kenjo, A., and M. Miyao. 2003. Etching characteristics of SiOj irradiated with focused ion beam. Nuclear Instruments and Methods in Physics Research B 206 478-481. 

In the operation of 2D and 3D quadrupole instruments, the modification of ion trajectories by ion/ neutral collisions must be considered. In rf quadrupole fields, an ion/neutral collision reduces both ion kinetic energy and ion excursions such that the ions are cooled and focused to the center of each field. Collisional cooling is an important aspect of the behavior of ions in a quadrupole field for example, in a 2D quadrupole device, collisional cooling is employed to limit the excursions of ions so as to form a tightly focused ion beam of diminished kinetic energy constrained close to the central axis. A focused beam of ions may be transmitted through a relatively small orifice from one section of an instrument to the next such that pumping requirements are reduced, and a focused ion beam can be accelerated with reduced ion loss. When the axial motion of a focused ion beam is arrested within a rod array such that the confined ions can be excited resonantly, a linear ion quadrupole trap is obtained. 

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