Authors: L. Scipioni, J. Notte
Affilation: Carl Zeiss SMT, Inc., United States
Pages: 871 - 874
Keywords: helium, microscopy
The helium ion microscope is offering new windows into nano-scale imaging. Unique sample interaction dynamics allow new types of sample information to be gathered. Some fundamental advantages conferred by probing a surface with a helium ion beam are the high contrast due to the sensitive material dependence of the secondary electron (SE) yield, the surface sensitivity arising from the low energy of the SE’s, and the ability to image low atomic weight materials due to a greater electronic cross-section of ions. The low mass of helium allows imaging via the collection of backscattered ions. There are also secondary benefits to helium ion microscopy. Ions beams allow easy imaging of non-conducting samples through the use of charge neutralization. The Orion™ tool is equipped with a low energy flood gun for this purpose and has been demonstrated effective even at high image magnification. The low mass of the helium ion minimizes beam induced damage – indeed on some materials sputtering is not detected even at doses far beyond that required for imaging. The much longer depth of focus of the microscope allows imaging of three dimensional objects or tilted cross-sections while maintaining focus over the entire field of view.