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edfas.org ELECTRONIC DEV ICE FA I LURE ANALYSIS | VOLUME 24 NO . 1 40 related to the user groups and introduced the chairs of the SOP User Group. Several topics from the previous SOPUser Groupwere brought up as primer topics. These included: sample size limitations of tools, sample damage during deprocessing, and dynamic lock-in thermography (LIT). This sparked a discussion related to sample mounting mediums during handling and processing. A few different glues were dis- cussed but several attendees brought up using mount- ing wax which can be reheated for sample unmounting or movement. Susan Li from Cypress/Infineon was the first panelist to present a primer topic. Susan covered the increasing complexity of semiconductors and how a shift to packag- ing development is occurring. This naturally results in smaller packages with chips cleverly packed together resulting in the line between packages and chips blurring or “merging.” Naturally, the discussion led to the difficul- ties these types of packages impose on the FA community; a statement the panelists all silently nodded to. Susan shared a particular case study related to TDR locating a solder non-wet in an interposer-based package. Several more discussions arose following the presen- tation. A question related to removing heat spreaders on these packages was brought up. A fewcareful approaches were suggested by attendees. Computerized numerical control (CNC) milling usage during die prep was another topic discussed, specifically when attempting to keep other chips in the assembly functional. Many agreed that experience and a certain level of care and patience is needed in this process, especially when dealing with a one-of-a-kind failure. The discussions moved right into Yan Li’s primer topic presentation. Yan showed illustrations of various advanced packages: Embeddedmulti-die interconnectbridge (EMIB), Foveros, chip-on-wafer-on-substrate (CoWoS), integrated fan-out (InFO) packageonpackage (PoP). Thepresentation also included some key components of these packages that a failure analyst would encounter: Thru silicon via, microbumps, and direct bond Cu interconnects. A fewkey challenges related to these features were then discussed. Several questions showed interest in the direct bond Cu interconnects process. The feature consists of intercon- nects which have no solder. Naturally, this introduces a new host of potential defects an analyst might need to find. Comments about potentially resistive materials at the Cu-Cu interface were made. The consensus was that analyses of suchmaterials would be within the capability of STEM. Another question came up about 3D x-ray of low- filler epoxy. Several peoplewith extensive x-ray experience discussed considerations related to this question such as using lower x-ray energy. The conversation continued a bit longer to discuss whether all x-ray tools are equal. Speaking of epoxy, the next primer presentation topic was presentedby KevinDistelhurst fromGlobalFoundries. The presentation focused on a recently published article in EDFA magazine related to enabling fault isolation on an interposer package by removing overmold. The topic discussed approaches to removing the overmold, which then enabled EBAC immediately after with no inadvertent damage to the sample. A small discussion took place around using a laser to remove the overmold; a topic not discussed in the article. The final presentationdove intocorrosionmechanisms of Cu wire bonding by Wentao Qin from OnSemi. The presentationwent over several mechanisms and sparked some discussions including those related to chlorine as a catalyst. The two hours allotted for the discussions came and went quickly. There is plentymore opportunity to discuss these topics on ASM Connect or, at least, at the next User Group session in 2022! T he FIB User Group meeting was held the after- noon of Wednesday, November 3, concurrent with the Contactless & Nanoprobing User Group. Considering the modest total conference attendance, drawing in better than 60 ‘Fibbers’ was a decent feat. The ISTFA 2021 FOCUSED ION BEAM USER GROUP Chair/Co-Chairs: Steven Herschbein, Michael Wong, Valerie Brogden, and Edward Principe steven.herschbein@gmail.com , mike.wong@thermofisher.com, vbrogden@uoregon.edu, eprincipe@synchres.com format was largely a carryover fromprior years beginning with a review of last year’s virtual event, reintroduction of the ASM Connect communities, and a short presenta- tion on the new EDFAS FA Technology Roadmap Council that is attempting to tackle the gaps between emerging