Since the introduction of copper metalization into mainstream semiconductor processes, new backend debug and failure analysis techniques are needed to deal with the different reaction rate and milling behavior of copper. Focused Ion Beam (FIB) systems have long been a major tool in debug and analysis of semiconductor chips. With the introduction of copper, many of the current FIB chemistries and techniques will need to be modified in order to accommodate this process. The metal etch gases currently in most FIB systems either have no effect on copper or have detrimental effects. Chlorine, iodine and bromine all will etch copper spontaneously and will undercut exposed copper lines. [1,2] The ion channeling properties of copper are also significantly greater than aluminum, which makes large area metal removal very difficult due to differential milling rates. Depending on the crystallographic grain orientation, straight sputter of copper could have up to 3 times differential milling rates. Various other FIB function will also need to be examined with regard to copper. This paper will discuss the differences in dealing with copper instead of aluminum chips. It will also offer a few application techniques and new system enhancements in dealing with copper and discuss some limitation of the current system hardware. [1]

FIB Micromachining has long been an established technique, but until recently it has been overshadowed by the more mainstream semiconductor application of the Focused Ion Beam system. Nano- Structure fabrication using the FIB system has become more popular recently due to several factors. The need for sub-micron structures have grown significantly due to a need for enhanced optical and biological applications. Another reason for the growth in micromachining is the improvement made in the ability of FIB systems to produce geometric shapes with high precision. With the latest high-end FIB systems, it is possible to produce microstructures with tens of nano-meters of precision. Optical lens, AFM tips, and nano-apertures are all part of the growing application for FIB Micromachining. This paper will discuss the ability and limitations of the FIB system and some possible application for FIB Micromachining.

The extensive use of planarization in many of today's leading process technologies significantly reduces the effectiveness of FIB circuit modification and debugging. Planarization has played a significant role in the development of denser chips with increasingly smaller geometries. Fully planarized devices offer little or no surface features on which the FIB operator relies for orientation and alignment. These conditions lead to increased debug cycle times and decreased success rates using the FIB. Recent FIB tool advancements in the field of C4 (controlled-collapse chip connection) flip-chip packaged device modification and debug have also made it easier to work on highly planarized conventional wire-bond technology. The integration of an optical microscope with an infrared camera into the work chamber allows the operator to view the circuitry under the surface layer. This paper will offer several techniques for overcoming the challenges that planarized devices present by using this in-situ optical microscope. When properly implemented, these techniques can significantly improve the success rate and throughput time of device modification on highly planarized parts.