| --- Wed Oct 19 2011 | 00:00 | |
| gkwhc | Hi, anyone here use "electric" to design ICs? | 19:12 |
|---|---|---|
| azonenberg | gkwhc: Last time somebody asked, no | 19:57 |
| azonenberg | most of us here are in the process deevelopment stage | 19:57 |
| azonenberg | not ready to do full vlsi | 19:57 |
| gkwhc | azonenberg: oh i see. would you happen to know of a channel related to this area? | 19:57 |
| azonenberg | gkwhc: This is pretty much the microfab/vlsi/mems channel on freenode | 19:58 |
| azonenberg | swkhan (not here atm) works in a real lab at nasa | 19:58 |
| azonenberg | most of the rest are hobbyists | 19:58 |
| gkwhc | azonenberg: great! | 19:58 |
| azonenberg | personally, i'm working toward a MEMS comb drive | 19:58 |
| azonenberg | and then 4000 series logic | 19:59 |
| azonenberg | in my living room | 19:59 |
| gkwhc | a home-fab? | 19:59 |
| azonenberg | gkwhc: look at the channel title lol | 19:59 |
| gkwhc | that's really neat | 19:59 |
| azonenberg | It's still under active development and we do not yet have anything working that well | 20:00 |
| gkwhc | i can't imagine the equipment costs, etc | 20:00 |
| azonenberg | I actually havent spent that much on it | 20:00 |
| azonenberg | i mean, my whole lab is maybe a few tens of K but most of that is the GPU cluster that isnt used for this at all | 20:00 |
| azonenberg | it was funded by some sponsored research a few years ago | 20:00 |
| gkwhc | ah i see | 20:01 |
| azonenberg | the nice microscope was $1k and that is the biggest single item i actually use for semiconductor stuff | 20:01 |
| azonenberg | probably 5-10 total? I mean, it might be a little much for the average hobbyist who isnt being backed by sponsored work | 20:01 |
| azonenberg | But for a hackerspace? | 20:01 |
| azonenberg | entirely feasible | 20:01 |
| azonenberg | http://colossus.cs.rpi.edu/~azonenberg/images/homecmos/2011-09-20/die_i4_009.jpg | 20:02 |
| gkwhc | yea | 20:02 |
| azonenberg | This is 20 micron half-pitch wires in copper on silicon | 20:02 |
| azonenberg | the background mottling is the incompletely etched chromium adhesion layer | 20:02 |
| azonenberg | I did the metal deposition in an evaporator on campus but will be buying a bell jar and vacuum pump soon so i can do metal evaporation at home | 20:02 |
| azonenberg | its a very simple process if you can get down to decently high vacuum | 20:02 |
| gkwhc | hm what do you use for etching? laser? | 20:02 |
| azonenberg | http://colossus.cs.rpi.edu/~azonenberg/papers/litho1.pdf | 20:03 |
| azonenberg | That's the exposure process | 20:03 |
| gkwhc | thanks! | 20:03 |
| azonenberg | i use the camera port method | 20:03 |
| azonenberg | then the metal etch is HCl : H2O2 | 20:03 |
| azonenberg | nice simple wet etch | 20:03 |
| azonenberg | http://code.google.com/p/homecmos/source/browse/trunk/lithography-tests/labnotes/azonenberg_labnotes.txt is my lab notes | 20:04 |
| azonenberg | which i actually have to update after my last (failed) experiment in Ta2O5 + Cr + Cu film patterning | 20:04 |
| gkwhc | i am surprised that you can manually etch 20micron wires! | 20:05 |
| azonenberg | 20 is actually doable with very good yield | 20:05 |
| azonenberg | http://colossus.cs.rpi.edu/~azonenberg/images/homecmos/2011-09-20/die_i4_002.jpg is the entire test pattern | 20:05 |
| azonenberg | a little edge roughness but 20um wires at 20um half-pitch all resolved beautifully | 20:05 |
| gkwhc | oh yes definitely | 20:06 |
| azonenberg | these were both imaged in a JEOL JSM-840 scanning electron microscope on campus | 20:06 |
| azonenberg | i use the SEMs for my nice PR shots or for debugging when i need really high resolution | 20:06 |
| azonenberg | i can only use them when the lab manager (who i have a good working relationship with) is around and nobody else needs the tool | 20:06 |
| azonenberg | lol\ | 20:06 |
| azonenberg | So for all of my in-process imaging i use the AmScope metallurgical light microscope | 20:07 |
| azonenberg | at home | 20:07 |
| azonenberg | not nearly as sharp but the images are in color | 20:07 |
| azonenberg | and quick turnaround | 20:07 |
| gkwhc | interesting! | 20:08 |
| azonenberg | http://colossus.cs.rpi.edu/~azonenberg/images/homecmos/2011-06-07/fab002_annotated.jpg was one of my early lithography tests | 20:08 |
| azonenberg | this is around 5 microns of SP24 photoresist over a tantalum oxide thin film | 20:08 |
| gkwhc | oh wow - 5 microns! | 20:09 |
| azonenberg | the Ta2O5 is transparent (yellow collor from diffraction), the reddish spots are pinholes in the film | 20:09 |
| azonenberg | thats thickness | 20:09 |
| azonenberg | the feature size is around 25 | 20:09 |
| gkwhc | i'll need to read more about the subject area | 20:09 |
| azonenberg | http://colossus.cs.rpi.edu/~azonenberg/images/homecmos/2011-06-07/fab004_annotated.jpg | 20:10 |
| azonenberg | thats a nicer shot with the amscope | 20:10 |
| azonenberg | i actually have two cameras, one of them is calibrated but a pain to set up (i need to haul my laptop out to the bench to connect to it) | 20:11 |
| azonenberg | the other is a point and shoot that i hold up to the eyepiece, good for quick in-process imaging if i dont care about exact dimensions | 20:11 |
| azonenberg | here's an image from that cam http://colossus.cs.rpi.edu/~azonenberg/images/homecmos/2011-08-06/S7301603.JPG | 20:11 |
| gkwhc | the resolution of that is impressive! | 20:12 |
| gkwhc | what camera do you use? | 20:12 |
| azonenberg | The calibrated camera is an amscope MD1900 | 20:13 |
| azonenberg | cheap optics, a nikon/zeiss/mitutoyo would be way better | 20:13 |
| azonenberg | but for $1200 camera + scope it was a great price | 20:13 |
| azonenberg | a mitutoyo FS-60 (my dream scope) would run over ten grand | 20:13 |
| gkwhc | thats really expensive, but what you have currently looks great already! | 20:15 |
| azonenberg | Yeah | 20:15 |
| azonenberg | The other camera is a $50 samsung point and shoot | 20:15 |
| azonenberg | thats the one i took the nyan cat shot with | 20:15 |
| azonenberg | Puns about "nyanotechnology" were too good to pass up lol | 20:15 |
| gkwhc | haha true! | 20:15 |
| azonenberg | so when i got bored of my other mask art i made this one | 20:16 |
| azonenberg | And he is truly a nanoscale cat | 20:16 |
| azonenberg | around 600 microns x 300, which is big | 20:16 |
| azonenberg | but only 200nm deep | 20:16 |
| azonenberg | from top of copper to the surface of the silicon | 20:16 |
| azonenberg | (approximately, that was the intended thickness when i ran the deposition but I havent actually done profilometry on it) | 20:16 |
| azonenberg | In the next day or two i am going to be doing Cr evaporation on a wafer | 20:18 |
| gkwhc | exciting! | 20:18 |
| azonenberg | lift-off patterning of 800-1000nm Cr over a photoresist pattern | 20:18 |
| azonenberg | to be followed by a KOH wet etch | 20:18 |
| azonenberg | if successful i can do a through wafer pattern | 20:18 |
| gkwhc | about how long would the whole process take? | 20:18 |
| azonenberg | well, i am going to be doing several dies by lift-off as well as a half-wafer to test etching of the Cr | 20:21 |
| azonenberg | The evaporator on campus is in the mat sci department, it takes an hour or so for the vacuum pump to warm up | 20:22 |
| azonenberg | then maybe 20 minutes to pump down the chamber, two or three for the actual deposition | 20:22 |
| azonenberg | spin coating photoresist on a batch of dies is maybe 5 mins | 20:22 |
| azonenberg | lithography is 5-10 minutes per die | 20:23 |
| azonenberg | metal etch is fast | 20:23 |
| azonenberg | then the through-wafer etch is a good couple of hours | 20:23 |
| azonenberg | but i can remove the die after 10 mins or so to see if its working | 20:23 |
| gkwhc | i see | 20:30 |
| gkwhc | thats pretty fast | 20:30 |
| azonenberg | The evaporation is something i do a big batch (usually half or a whole 2-inch) every few weeks since i just need films to pattern and they last me a while | 20:30 |
| azonenberg | i'm not doing any multilevel metalization yet | 20:31 |
| kristianpaul | I'll buy a scope as soon i see this work can be asilly reproducesable and sourcable :) | 20:31 |
| azonenberg | kristianpaul: We're working on that | 20:31 |
| kristianpaul | last pic looks nice, where came froma ctually? | 20:31 |
| azonenberg | i'm still hoping to have a comb drive by end of year, i have most of the essentials donated | 20:31 |
| azonenberg | nyan cat? | 20:31 |
| kristianpaul | ahhh ! | 20:31 |
| azonenberg | donated? what am i saying | 20:31 |
| azonenberg | designed | 20:31 |
| kristianpaul | from fab004 i tought was another thing :) | 20:32 |
| azonenberg | and the last pic is one of my earliest tests when i was experimenting with litho techniques | 20:32 |
| azonenberg | lol | 20:32 |
| kristianpaul | indeed nice camera resolution | 20:33 |
| kristianpaul | also bundle price i guess :) | 20:33 |
| azonenberg | yep | 20:33 |
| --- Thu Oct 20 2011 | 00:00 | |
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