The invention relates generally to ion beams and more particularly to compact focused ion beam systems for generating ion beams of various elements with ion beam output currents of 1 .mu.A or greater and final beam spot size down to 0.1 .mu.m or less for lithography and doping applications.
As the dimensions of semiconductor devices are scaled down in order to achieve ever higher level of integration, optical lithography will no longer be sufficient for the needs of the semiconductor industry. Alternative "nanolithography" techniques will be required to realize minimum feature sizes of 0.1 .mu.m or less. Therefore, efforts have been intensified worldwide in recent years to adapt established techniques such as X-ray lithography, extreme ultraviolet lithography (EUVL), and electron-beam (e-beam) lithography, as well as newer techniques such as ion projection lithography (IPL) and atomic-force-microscope (AFM) lithography, to the manufacture of 0.1 .mu.m-generation complementary metal-oxide-semiconductor (CMOS) technology. Significant challenges exist today for each of these techniques: for X-ray, EUV, and projection ion-beam lithography, there are issues with complicated mask technology; for e-beam and AFM lithography, there are issues with low throughput.
Focused ion beam (FIB) patterning of films is a well-established technique (e.g. for mask repair), but throughput has historically been a prohibitive issue in its application to lithographic processes in semiconductor manufacturing. A scanning FIB system would have many advantages over alternative nanolithography technologies if it can be made practical for high volume production. Such a system could be used for maskless and direct (photoresist-less) patterning and doping of films in a semiconductor fabrication process. The main problem with present FIB systems is low current, on the order of nanoamps or picoamps. It would be desirable to have a compact FIB system which produces ion beam currents on the order of microamps. It would also be necessary to focus the beam down to sub-micron spot sizes.