Technological Developments Enabling Improved Cryo-Laser PFIB Workflows¶

Since 2019, several technological developments have been commercialized which enable significant improvements to Cryo-Laser PFIB workflows.

• Cryo-stage improvements: More recent cryo-stage designs allow for 360° rotation, where the top plate of the cryo-stage rotates freely. With full rotation capability, PFIB polishing could be done on cross-sections after UPL ablation without venting the chamber to manually rotate the sample. This also prevents ice contamination from forming during the vent cycle.

• Laser improvements: Commercial Laser PFIBs (Helios 5 Laser platform) have higher laser power output (more pulse energy) that could further improve throughput or enable deeper UPL cross-sectioning in harder or thicker materials and systems.

• Multiple plasma ion species: In recent years, Thermo Fisher Scientific released a multiple ion species PFIB (Helios Hydra) which can generate Xe⁺, Ar⁺, O⁺, or N⁺ ions, where other ion species could result in improved cross-section quality. Higher PFIB beam currents are also available, which could improve throughput to enable more practical PFIB polishing of larger areas.

• Automation capabilites: AutoScript, a Python based application programming interface for microscope automation, has been developed by Thermo Fisher Scientific which allow users to build custom automation solutions. For example, the UPL cross-sectioning and subsequent PFIB polishing and SEM imaging could be fully automated via AutoScript. Customizable 3D workflows could also be built and could include analytical steps such as EDS mapping.