Advanced 10 nm device delayering is a critical process for verifying and validating the circuit design layout and extracting the structures buried inside the chip. The work featured in this article takes advantage of chemically assisted focused ion beam processing with ultraviolet spectroscopy to destructively delayer integrated circuits starting from the shallow trench isolation layer, enabling high-resolution SEM imaging at each layer.

This article discusses the challenges associated with nanoprobing advanced technology node devices and explains how to optimize SEM images for beam voltages of 100 eV or less.

A detailed analysis based on FIB etching and SEM image capture was conducted on a flip-chip solder joint deep inside a tablet PC. 3D views reconstructed from SEM images show what appears to be a copper pillar with a solder cap connected to a copper trace on the substrate. The investigators believe the joint was formed by thermal compression bonding with a preapplied underfill. The analysis also revealed the presence of voids and intermetallic compounds along with signs of filler entrapment.

The sixth FIB-SEM workshop was held March 1, 2013, in Cambridge, Mass. This article provides a summary of the event along with highlights from the 18 paper presentations.

FIB milling is difficult if not impossible with III-V compound semiconductors and certain interconnect metals because the materials do not react well with the gallium used in most FIB systems. This article discusses the nature of the problem and explains how cryogenic FIB-SEM techniques provide a solution. It describes the basic setup of a FIB-SEM system and provides examples of its use on InN nanocrystals, GaN films, and copper-containing multilayer photovoltaic materials.

The introduction of ultralow-k dielectrics is a recent milestone in the quest for higher clock speeds and lower power consumption in ICs. One tradeoff, however, is that interconnect stacks layered with low-k materials rather than SiO 2 are more vulnerable to mechanical damage. This article presents a method that makes it possible to assess the mechanical integrity of interconnect stacks at the wafer level. The new bump-assisted BEOL stability indentation (BABSI) test uses a nanoindentation tool to apply lateral and vertical forces to solder bumps and copper pillars on the wafer surface. By applying appropriate stresses, various aspects of integrity, such as the onset of failure modes or the weakest interface in the stack, can be determined by subsequent SEM/FIB analysis. The authors describe the basic principles of the measurement technique and some of the applications in which it was used.

Packaging integration continues to increase in complexity, driving more samples into FA labs for development support and analysis. For many of the jobs, there is also a need for larger removal volumes, compounding the demand for tool time and throughput. Focused ion beam (FIB) and dual-beam FIB/SEM systems are helping to relieve the pressure with their ability to create site-specific cross sections and to facilitate gate-level circuit rewire and debug. This article reviews the impact of packaging trends on failure analysis along with recent improvements in FIB technology. It also presents examples that illustrate how these new FIB techniques are being applied to solve emerging packaging challenges.

The combination of microcleaving and precision broad ion beam techniques allows failure analysts to prepare site-specific specimens for SEM analysis with 0.5 μm accuracy. Microcleaving, as the article explains, uses the cleaving characteristics inherent in single-crystal semiconductor substrates. Because the substrate has significantly more mass than the process layers, it dictates the overall cross-section quality and precision of the sample. The cleave loses no material, preserves the integrity of the designated area, and enables analysis of both sides of the cross-section. When the cleave is off-set due to a buried target or when debris lies on the surface of the cross-section, ion beam etching and coating are used to fine tune the cleave location and remove debris prior to SEM analysis.

Experiments to assess microelectromechanical systems (MEMS) test their functionality and materials properties. These experiments provide knowledge and insight into MEMS failure modes and potential pathways to improve the lifetime of MEMS devices. This article demonstrates the use of optical microscopy and SEM analysis to determine various causes of failure in MEMS devices.

This case study describes the difficulties and challenges failure analysts encountered in their nearly year-long investigation into the cause of cracking in a dielectric film. Despite the trend in microelectronics to use ever more costly and sophisticated equipment, this investigation was conducted using only SEM and optical microscope observations coupled with persistent detective work, which eventually uncovered to the cause.