Miniature columns or microcolumns are a relatively new class of electron beam columns fabricated entirely from silicon using advanced micromachining processes. The main characteristics of these columns are a thermal field emission (TFE) source, low voltage operation (typically <3keV), simple design (two lenses, no crossover), microfabricated electrostatic lenses, and multilayer ceramic interconnects. Current production versions of miniature columns achieve <10nm resolution at 1keV, and have demonstrated <6nm resolution at higher beam energies. Recently, a positively bias sample carrier has provided a path to high energy electrons enabling high-resolution energy dispersive spectroscopy (EDS) and other microcopy techniques.
With this level of imaging performance, ease-of-use, compact form factor, and quantitative analysis capabilities, the miniature columns are ideal for a variety of applications ranging from material science to life sciences. Looking ahead, large arrays of miniature e-beam columns may be the only way to address the high throughput requirements of wafer fabrication making the miniature e-beam technology attractive to semiconductor manufacturers and designers.
The technology behind the columns, specific applications in nanotechnology and some projected capabilities for arrays in wafer inspection will be discussed in several parts. Other examples of applications for this type of tool will be presented if time permits.