(Invited) The Laser-Integrated FIB-SEM for Faster 3D Packages Characterization and Failure Analysis
Authors: Vertsanova Olena , Tordoff Benjamin 
Published: February 2024

The semiconductor industry is constantly looking for new technologies and materials to provide more functionality and performance in a smaller volume.
Modern innovations in the development of 3D advance packaging require new methods of materials research and failure analysis. Three-dimensional multi-level electronic components, whose packages contain a stack of chips and interconnections, require visualization and analysis of undersurface structures withhigh resolution and performance [2].
Modern methods of electron microscopy based on ion beam (FIB-SEM) sample preparation provide a high quality of the cross-sectional surface and accurate
information about the subsurface structure, however, FIB-SEM does not provide access to deep buried structures and high speed of sample preparation, what is required by the modern electronics industry. A unique solution for cross-sectional access to deeply buried structures is the integration of a laser beam into the FIB-SEM (laser FIB), which provides fast removal of large volumes of material with high speed. Laser FIB provides all advantages of integrates a fs-laser for speed, a Ga+ beam for accuracy, and a SEM for high resolution imaging to enable the fastest workflows. The isolated laser chamber prevents contamination of the electron column and detectors, while ensuring sample integrity with automated transfer between the SEM and laser chamber
under vacuum. Integration of the laser and FIB into a single system, automation of process parameters and laser shuttling and correlative workflows provide the fastest results and highest success rates. Fs-laser ablation is a thermal so the laser affected zone is minimal, and it is often possible to image cross sectional structure immediately after laser ablation, without FIB polishing [1].
The latest developments, implemented in the laser-integrated FIB-SEM, such as an automated shuttle, NavCam integration, preset recipes, and the Cross-jet option for cover glass protection, improve the cross-sectioning process and ensure the automation, repeatability, and efficiency of the sample preparation. The combination of batch mode and other parameters of the laser milling process improves the high ablation rate and surface quality, which is especially effective for wide-gap semiconductor cross-sections. A combination of 3D X-ray microscopy (XRM) techniques and integrated laser scanning electron microscopes with a focused ion beam for sample preparation provides a workflow to improve precise targeting for specific analysis of buried
features and correlation with additional equipment to provide subsurface analysis [3]. We describe a workflow using 3D XRM and Laser FIB for precise targeting and high throughput results and demonstrate the application examples. Correlated workflows accelerate results by connecting tools to quickly navigate between multiple length scales and imaging modes.
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