PORTLAND, Ore.--Semiconductor development has long depended on high-end focused ion beam (FIB) tools to cut cross-sections that reveal details views of advanced processes down to the nanoscale. However, these tools could take up to 12 hours to dissect the micron- and millimeter-scale features of MEMS chips and of 3-D stack chips, such as through-silicon vias (TSVs). Now, tool vendor FEI Co. claims to have reinvented the focused ion beam for 3-D ICs and MEMS.
"MEMS devices and next generation packaging features, such as TSVs for memory-on-logic devices, are too small for mechanical manipulations, but too big for focused ion beams," said Peter Carleson, a product marketing manager at FEI. "Features measuring 100s of microns can takes hours, but by redesigning the Vion to handle higher currents, we can work at these larger scales."
FEI claims its newly redesigned Vion plasma focused ion beam (PFIB) tool can cut the time to image MEMS and 3-D chip features by 20-times, down from more than 10 hours to under 40 minutes for TSVs. The new tool can reveal semiconductor features in minutes that range in size from 30 nanometers to 1-millimeter, compared to existing focused ion beams that work at down to five nanometers, according to the firm.
"The increased milling speed provided by FEI’s Vion PFIB system lets us perform analysis in minutes, as opposed to several hours on a conventional FIB," said Peter Ramm, head of the department for device and 3-D integration at Fraunhofer.
Used for failure analysis of micron-scale features of both packaging and MEMS devices, the new Vion focused ion beam is the first FEI tool to incorporate plasma source technology. Plasma enables it to quickly perform cross-sectional analysis by using more than a microamp of beam current, compared to nano amps used for traditional focused ion beams with liquid metal ion sources.
Besides dissecting 3-D stacked chips and MEMS devices, the Vion PFIB system can be used in failure analysis of bumps, wire bonds, and other package-level tests and modifications.
Vion plasma focused ion beam cuts imaging time for this through-silicon via (TSV) for 3-D stacked chips from 12 hours to 40 minutes.
Using mA current instead of nA current can surely help analyzing circuits faster. I am not aware of the history of the ion-beams as to why other companies did not use higher current before. One hurdle that i can think of is higher charge interaction thus loss in resolution.
3-D chip makers can now accelerate their development efforts with FEI's new Vion too, according to Fraunhofer, the European research lab that is developing advanced chip stacks. MEMS devices, which also work on the micron-scale, should be able to benefit from quicker metrology and characterization.
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