NetNotes


Looking forward to the new opportunities and collaborations. Sergei V. Kalinin sergei2@ornl.gov Wed Sep 26


TEM: combined cryo and standard TEM usage I would like to know the feasibility of having a TEM operate on a


weekly basis both as a standard electron microscope and a cryo-electron microscope. Is this practical? Michael Delannoy mdelann1@jhmi.edu Wed Oct 3 In general, it is very possible to use a TEM in cryo or standard


mode intermixed, if the “cryo” use involves a “cryo holder” and not a fully chilled cryo-stage. A JEOL 3200 cryo, would be a full cryo stage and not switched easily between projects. Using a cryo-holder such as the one Gatan sells, with a liquid nitrogen reservoir and cryo shields, so that the sample is protected during transfer to the column, is quite fine. UC Berkeley has been doing cryo-TEM and non-cryo in the same CM series TEM for decades. Most materials people do not fully understand polymer or biological “cryo” work, so there will be some learning involved. I’ve been lucky to have participated on the both sides of the TEM world. Roseann Csencsits rcsencsits@belcan.com Wed Oct 3 Tere is no general answer, honestly. It depends on the facility, it


very much depends on the training of the various users you have—you have to get trained and to supervise, on the equipment, and it depends on the TEM that you have. Yes, we do it, not on weekly basis, but with daily varying schedules, and this works. Fine. Little problems, only, which are due to the limited training of the users, rather than the TEM. If you know exactly what your TEM can do and to tolerate, and what your users know, then YES, it is possible. Ten, I do not see any reason why a weekly schedule would not work. Reinhard Rachel reinhard. rachel@biologie.uni-regensburg.de Wed Oct 3


FIB: charging I need some advice on sample prep for FIB. I have packaged parts,


with gold bond wires, that goes into a FIB to do circuit edits. Due to the samples being in a package, the samples would charge. If I coat the sample, it would help the charging issue, but then I need to remove the coat aſter I’m done with the FIB edits. Does anyone have any suggestions on what to coat it with and how to remove the coat aſterward? Gordon weutro@yahoo.com Sun Oct 14 Use your micro manipulator to earth the local region. But be careful


not to blow any sensitive circuits. Richard contact@integrityscientific. com Sun Oct 14 If you set proper GAE processes and use primary ion beam


currents appropriate for edits, then there wouldn’t be any problems with surface charging or ESD damage. If there is no time/bandwidth/ money/expertise to accomplish the above, then there are two surface coating options suitable for brute-force elimination of surface charging during FIB circuit edit: (a) carbon, either evaporated or PIPS, or conductive polymers, either spin-coated or ultrasonic- nozzle dispensed. Carbon deposited with thickness of about 20 nm provides sufficient charge dissipation for CE-appropriate beam currents while having little to no inf luence on regular operation of most ICs so that it can be left on in most cases. If removal is required, then O2


plasma cleaner (< 20W), or ozone asher, or UV cleaner would


work (from fastest to slowest) depending on sensitivity of the device. Conductive polymers simply washed away after the edit site has been capped and sealed. Google for “Free of charge FIB circuit edit of ICs” and “New FIB tricks with old conductive polymers” I am assuming that all pins of device under edit already have solid connection to the stage of your CE FIB. Valery Ray vray@partbeamsystech.com Mon Oct 15


2019 January • www.microscopy-today.com


Sorry for the shameless self-promotion, but we published a paper


a little while back about using conductive polymers (used for e-beam lithography) in the FIB. We were using it on flat wafer samples, but you might be able to adapt the technique we described for your needs. Most of the polymers are water soluble and can be removed with a rinse aſterward. Please let me know if you need a PDF copy of the article. https:// www.cambridge.org/core/journals/microscopy-and-microanalysis/ article/teaching-an-old-material-new-tricks-easy-and-inexpensive- focused-ion-beam-f ib-sample-protect ion-using-conduct ive- polymers/7E9EAE6546D968E9537A56CFDB70D6AA. Josh Taillon joshua.taillon@nist.gov Mon Oct 15


FE-SEM: gun lifetime I’ve sort of inherited oversight of a shared EM facility that includes a


2-year old FE-SEM. Unfortunately, the system does not get much use, so I’d like to be able to shut down the gun when there are no projects anticipated - it just costs too much for us to be able to replace the tip every 12-16 months. Te original one was swapped out at just under 24 months of age with less than 200 hours of actual use. It was still working & seemed to be stable but was well over the suggested run time. I’ve been told by various people that there are facilities that routinely turn their FE-gun off when not in use, but they did not know if anyone had standardized a re-start procedure. So, my question is: would anyone who does this mind sharing how they manage this? I will see replies to the ListServer; I’m having some issues with Outlook and could not post directly. Tanks for your help! Tamara Howard thoward@unm.eduSat Oct 27 Inheriting other microscopes can be a giſt or a burden - who knows.


But in this case, a 2-yr old FE-SEM is usually a wonderful giſt. Te original gun was swapped out at just under 24 months of age? Strange. If it is an FE-gun, it can live ‘forever’, if not heavily used. In our FE-SEM (from 1999), we had one for far more than five years with little/occasional use (before I got it). What a shame for such an instrument. Te gun was fine. But, aſter 200 hrs, an FE-gun is not “well over the suggested run time.” No, never. A tungsten filament may be. But even then: if it still gives nice images, it was treated well, and it can stay there. You write: “it was still working & seemed stable” - then, why changing? Although, exchanging a W filament is not too tricky, and from the budget, not too heavy. Basically, for all types of filaments, it is the usage and the vacuum, which limits the lifetime. Te level of vacuum which is required, is very different, for the different guns (W, LaB6


, FE). IF you have an FE-SEM,


then you may ask the manufacturer for an appropriate treatment during extended periods of “no use.” And they also should have a procedure for a proper re-start. Our FE-SEM and also our FE-TEM, both have one. For extended periods, I use the shut-down / re-start of the manufacturer). Works fine. - In our W-SEM and W-TEM, filaments are used until burnt. Reinhard Rachel


reinhard.rachel@biologie.uni-regensburg.de


Sun Oct 28 Tere are two types of field emission guns; both have significantly


different lifetimes. One is a thermal, or Schottky field emission source, and the other is a cold field emission source. I have seen cold field emission sources last for ten years under the right conditions. Schottky field emission sources do have a finite lifetime, as the ZrO2


reservoir is


depleted, but this depends on how long it is on. Typically a thermal field emission source is ramped up over a 45 minute period, then stays in an emission state for prolonged periods of time, as with the Zeiss/Leo field emission systems. Which microscope do you have? Justin A. Kraſt kraſtpiano@gmail.com Sun Oct 28 A rep in your area for the original equipment manufacturer


should be willing to help you with this even if the instrument is not under warranty and rather old. Probably someone on the list will have an answer but connect with the OEM rep, too. Kleo Pullin kleopullin@ email.arizona.edu Sun Oct 28 As Reinhard stated, an FE gun should last much longer. However,


we had one of those rare instruments in which our gun went out aſter one year. It is not common, but it happens. R. Steven Pappas rlp6@cdc. gov Mon Oct 29


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