Move the Laser Spot, Not the DUT: Investigating the New Micro-mirror Capability and Challenges for Localizing SEE Sites on Large Modern ICs

Small spot size laser testing for single-event effects has proven to be a particularly productive path to insights on the physics of charge collection and circuit response that are difficult or impossible to obtain through broad ion beam tests. As a result, there are a number of such laser facilities; for example, four of them were compared in 2012 [1], but a relatively new facility at the facility at the University of Saskatchewan offers a unique galvo-mirror, laser-spot scanning capability in addition to the usual micrometer-based DUT motion stage [2]. Operating in a fashion similar to LASIX eye surgery, fast pin-point redirection of the laser beam makes tractable (seconds, not hours or days) comprehensive scanning of a millimeter size field-of-view. Combined with auto-stepping the field-of-view, this new spot scanning capability opens up the possibility of comprehensively covering a large die and finding all SEE sites, including the rare, but important, ones such as SEFIs.