Sunday, March 29, 2015

Cleanrooms - what is new and exciting?

Cleanrooms - basically climate-controlled, dust-mitigated environments filled with equipment useful for micro/nanoscale fabrication and associated characterization - are a staple of modern research universities.  What kind of tool set and facilities you need depends on what you're trying to do.  For example, if you want to teach/do research on the fabrication of high performance Si transistors or large-scale integrated circuits, you probably want a dedicated facility that deals primarily with Si CMOS processing.  That might include large-area photolithography or wafer-scale e-beam lithography or nanoimprint lithography tools, evaporators/sputtering systems/PECVD/RIE/ALD systems able to service 150 mm or 200 mm substrates, and you might want to keep non-Si-friendly metals like Au far far away.  On the flip side, if you are more interested in supporting microfluidics or MEMS work, you might be more interested in smaller substrates but diverse materials, and tools like deep etchers and critical point dryers.

We're about to embark on a cleanroom upgrade at my institution, and I would appreciate input from my relevant readers:  What in your view is the latest and greatest in micro/nanofab tools?  What can't you do without?  Any particularly clever arrangements of facilities/  Assume we are already going to have the obvious stuff, and that we're not trying to create a production line that can handle 200 mm substrates.  Conversely, if you have suggestions of particular tools to avoid, that would also be very helpful.  Insights would be greatly appreciated.

6 comments:

Anonymous said...

You may want to look at this cleanroom at Delft Univ. of Technology.

http://www.dimes.tudelft.nl/EKL/Home.php

and this one
http://kavli.tudelft.nl/kavli-nanolab/

Anonymous said...

Avoid Trion etchers

Brian J. said...

Don't overspec it.

I've been told by someone who claimed to do the experiment that they put some monitor wafers out in the parking lot for the specified time. The parking lot came out really well; Class 10000 I think? You should have a grad student try that test; it would be enlightening for all.

In my experience, clean rooms suffer from a "hey, we could do this also, it can't hurt" mentality, which is fine for performance but drives the cost up up and up.

JonB said...

This response is very much biased towards materials characterization...

Focused ion beam (FIB) systems have radically changed the field of materials characterization: >80% of TEM sample prep we do is now FIB-prepared and our FIB-SEM system is massively overbooked. This tool is now used for mechanical testing too, e.g. micropillars for crack-free plasticity testing at room temp (Uchic et al, Science 2004).

Top of our wish-list is the Zeiss Orion NanoFab (www.zeiss.com/orion-nanofab). There are significant surface-damage related problems with Ga-ion beam FIBs that make them problematic for delicate electronic devices (Ga diffusion along Al GBs is notorious), so having multiple noble-gas ion beams is a significant step forward.

Douglas Natelson said...

Thanks, everyone. Brian, yeah, clean-ness is way overrated unless you're trying to get very high yields on massively parallel processes or large areas (Intel, Western Digital patterned HDD media). We routinely do nanofab processes (e-beam, evaporations, etc.) that don't involve any "clean" environments, and they usually work out fine (or fail for reasons that have nothing to do with dirt). It is nice, though, to have enough room to move around comfortably and service the tools, and to have the utility and exhaust capacity for expansion.

JonB, I would desperately love a super-advanced He ion beam system (saw a great talk at the APS by a scientist at UCSD who has done amazing work with one), but that's likely on the boutique side for us for the moment.

Anonymous said...

I have had positive experiences with SAMCO etchers as a graduate student. If possible, avoid Oxford Instruments. Their tools seem to have design problems and their software is poorly designed.