Laser Testing for Single-Event Effects:
Some Thoughts from a User Perspective
Gary M. Swift1
1 Swift Engineering and Radiation Services, LLC, San Jose, Calif. USA
Whoa, Nellie Belle! The physics of charge deposition, collection, and circuit response is super complicated and the holy grail of matching- and eventually superseding- heavy ion testing with laser testing for single-event effects (SEE) purposes is, if not an impossible quest, very near so. Or maybe recent breakthroughs in modeling deposition  &  make this a solved problem.
Shoot, laser testing itself is extremely sophisticated, delicate, and difficult. As a long-time experienced ion beam tester who has admired several laser labs from afar and, more recently, dabbled in using a couple of laser facilities, my hat is off to those brave- or foolhardy- enough to attempt to provision and support laser SEE testing.
But not to worry, there are a fair number of tractable problems to solve and practical issues to research, particularly with regards to large die devices and two-photon absorption (TPA) testing. These include: single shot use and reproducibility, efficiently moving the target or spot , back-and-forth upsets, collection and categorization of SEE signatures, TID-like damage, avoiding killer damage, TPA tradeoffs, auto focus depth, user interfaces and more.
Mostly these leverage the complementary aspects of focused laser testing rather than the “competitive.” IMHO, the real goal is to use the right tool at the right time and in the right way and the real holy grail for laser SEE testing is localization. This is a “needle-in-the-haystack’ problem and means developing tools and techniques to efficiently find a particular and rare example SEE site on complicated, large-area, flip-chip devices, including precise timing signal exchange between the laser system and DUT board and detailed automated logging. Localization best practice likely includes ion-beam testing in conjunction with laser testing .
Another worthy aim of laser testing on large, complicated devices is to define the logical to physical map, a key step in SEE mitigation for memory arrays. This mapping can be done using heavy ion irradiation only in a statistical way , but doing this with a laser seems much more clear and direct. However, to be usable, a lot of automation is needed and will likely be obstructed by some of the unsolved problems listed above.
 J. M. Hales, A. Khachatrian, S. Buchner, N. Roche, J. Warner and D. McMorrow, "A Simplified Approach for Predicting Pulsed-Laser-Induced Carrier Generation in Semiconductor," in IEEE Transactions on Nuclear Science, vol. 64, no. 3, pp. 1006-1013, March 2017, doi: 10.1109/TNS.2017.2665546.
 J. M. Hales, A. Khachatrian, S. Buchner, N. Roche, J. Warner, Z. E. Fleetwood, A. Ildefonso, J. D. Cressler, V. Ferlet-Cavrois and D. McMorrow, "Experimental Validation of an Equivalent LET Approach for Correlating Heavy-Ion and Laser-Induced Charge Deposition," in IEEE Transactions on Nuclear Science, vol. 65, no. 8, pp. 1724-1733, Aug. 2018, doi: 10.1109/TNS.2018.2828332.
 M. Cannon, A. Pérez-Celis, G. Swift, R. Wong, S. Wen and M. Wirthlin, "Move the Laser Spot, Not the DUT: Investigating the New Micro-mirror Capability and Challenges for Localizing SEE Sites on Large Modern ICs," 2017 17th European Conference on Radiation and Its Effects on Components and Systems (RADECS), Geneva, Switzerland, 2017, pp. 1-4, doi: 10.1109/RADECS.2017.8696180.
 W. Rudge, C. Dinkins, W. Boesch, D. Vail, J. Bruckmeyer and G. Swift, "SEL Site Localization Using Masking and PEM Imaging Techniques: A Case Study on Xilinx 28nm 7-Series FPGAs," 2016 IEEE Radiation Effects Data Workshop (REDW), Portland, OR, USA, 2016, pp. 1-6, doi: 10.1109/NSREC.2016.7891736.
 M. Wirthlin, D. Lee, G. Swift and H. Quinn, "A Method and Case Study on Identifying Physically Adjacent Multiple-Cell Upsets Using 28-nm, Interleaved and SECDED-Protected Arrays," in IEEE Transactions on Nuclear Science, vol. 61, no. 6, pp. 3080-3087, Dec. 2014, doi: 10.1109/TNS.2014.2366913.
 For XRTC current activites, see: http://xrtc.groups.et.byu.net/wiki
Gary would like to thank and acknowledge the Xilinx Radiation Test Consortium  and, in particular, some key members who shared in both vain and fruitful attempts to use laser testing on a large-die: Harris (now L3Harris), NASA/Jet Propulsion Laboratory, NASA/Goddard, Boeing, and especially Brigham Young University. Also, a big “Thank You!” to the remarkably welcoming and smart researchers at the two laser facilities that hosted our efforts: the US. Naval Research Lab and Canada’s University of Saskatchewan.