Carl Zeiss sets record in microscopy resolution
-- Test & Measurement World, 12/3/2008 7:00:00 AM
Carl Zeiss SMT has set a new record resolution benchmark for scanning electron and ion microscopy—pushing scanning beam technologies beyond its current limits. By employing Zeiss’ Orion helium-ion microscope, a surface resolution of 0.24 nanometer has repeatedly been achieved (25–75% edge-rise criterion) on various samples. According to the company, this resolution, which is close to the diameter of a single atom, is three times better than even the most sophisticated scanning electron microscopes are able to achieve today with the same surface sensitivity. Existing customers will have an opportunity to upgrade their systems to this performance level.
“This unmatched resolution for surface imaging with scanning electron and ion microscopes is extremely important for semiconductor manufacturers and many others who need to see small features that currently cannot be resolved,” said Dr. Nicholas P. Economou, senior VP of Carl Zeiss SMT.
The ongoing shrinkage of feature sizes of semiconductor devices makes extreme high resolution microscopy very useful. “Some layers of integrated circuits already have reached a thickness of only a few atoms,” said Dr. Rainer Knippelmeyer, senior VP of operations of Carl Zeiss SMT. “Semiconductor manufacturers are in dire need of reliable high-resolution, surface sensitive metrology and process control tools. With the Orion helium-ion microscope we offer exactly the tool the industry and nanotechnology research needs and we continue to keep pace with the industry’s rapidly changing requirements.”
The secret behind the extreme high resolution of the helium-ion microscope lies in the proprietary source technology and the interaction between the scanning ion beam and the surface of the specimen. The source of the microscope is very small and the helium ions emanate from a region as small as a single atom. Unlike electrons, the helium ion has a very small wavelength, so it does not suffer appreciably from adverse diffraction effects, a law of physics which fundamentally limits the imaging resolution of electrons. Also, the helium ion beam triggers signals directly from the surface of the sample and stays very collimated upon entering the sample. This results in sharp, surface sensitive images at the quoted resolution, which can be easily interpreted. In contrast, Zeiss claims that for a typical SEM, the majority of the secondary electrons that are used for imaging come from deeper and much less confined regions within the sample, creating blurrier images with less resolution than the Orion helium-ion microscope.
Carl Zeiss SMT, www.smt.zeiss.com/orion.
