Date: Oct 24, 2002 Source: Machine Design (
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IBM (www.ibm.com) and Nion Co., Kirkland, Wash. (www.nion.com), researchers have developed a new technique that significantly boosts resolution of electron microscopes.
Electron microscopes use magnetic optics to locus electrons into extremely small-diameter beams to view atomic-scale details in thin slices of materials, important in the development of ever-smaller microchips. For years, engineers employed single lenses to reduce image-blurring lens imperfections such as spherical aberration, but with little success.
The new approach instead uses seven sets of computer-controlled magnetic lenses to actively correct spherical aberration in real time. The improved optics make possible an electron beam only 75 thousandths of a nanometer (3 billionths of an inch), smaller than a single hydrogen atom, said to be the smallest to date. This higher resolution lets scientists better see important defects in silicon and ways to fix them, for instance. It also permits the imaging of atoms interacting with one another, a key step to making self-assembling computer chips, says IBM.
