ABSTRACT
The focused ion beam (FIB) has been a well-established tool in the semiconductor industry mainly for applications like integrated circuit repair and debugging, device modification and failure analysis. Advances in FIB technology in achieving a tighter focus and integrated analysis tools (scanning electron microscope [SEM], X-ray diffraction, etc.) have made micromachining by FIB more attractive for researchers. This is mainly due to its high-resolution, one-step maskless fabrication and possibility to work with a variety of materials and geometries (two-and three-dimensional). As is evident from Figure 7.1a, micro-sized logos of IIT Bombay and WinTech
CONTENTS
7.1 Introduction ................................................................................................ 155 7.2 FIB System ................................................................................................... 157
7.2.1 Ion Source........................................................................................ 159 7.2.2 Imaging ........................................................................................... 160 7.2.3 Sputtering........................................................................................ 161 7.2.4 FIB-Induced Chemical Vapour Deposition ................................ 162 7.2.5 Material Self-Organisation ........................................................... 164
7.3 TEM Sample Preparation .......................................................................... 165 7.3.1 FIB for TEM Sample Preparation ................................................. 166
7.3.1.1 The H-Bar Technique ...................................................... 166 7.3.1.2 The Lift-Out Technique .................................................. 168
7.3.2 FIB-Induced Damage ..................................................................... 170 7.4 Conclusions ................................................................................................. 172 Acknowledgements ............................................................................................ 173 References ............................................................................................................. 174
Nano, with nanometer features, are directly patterned, without using any mask, on silicon using FIB and imaged using SEM in the same setup. Figure 7.1b demonstrates patterning of an artistic castle on a Ni material. In addition to the nano-fabrication capability, the FIB can be further used to polish surfaces to attain low loss, highly reflective mirrors, typically required in micro-devices/components such as planar photodiodes, surface emitting lasers, optical interconnects, etc. [1]. The flexibility of the direct milling and the ion beam manipulation enables polishing along various orientations.
