#homecmos IRC log for Sunday, 2012-01-08

--- Sun Jan 8 201200:00
azonenberghi :)18:35
azonenbergI'm serious about the "home" part btw lol18:35
barrettfriedmanI evidently need more sleep. I misread for a second... "Hebrew" CMOS and MEMS foundry design18:36
azonenbergMostly been pushing lithography, i have 20 micron patterning working reliably and am working on shrinking to 2ish using commercially made 8000DPI film masks18:36
azonenbergi have the beginnings of a vacuum setup but still use an evaporator on campus for doing film deposition18:37
azonenbergall of the spin coating, lithography, and etching are in my home lab18:37
barrettfriedmanKeeping it simple I see.18:37
azonenbergAdmittedly my lab is a bit better equipped then your average hobbyist http://imgur.com/a/Y3m0L#318:37
azonenbergyes that's a 4" wafer prober on the right18:38
barrettfriedmanHow are you dealing with the vapors involved in etching processes?18:38
azonenbergHomebrew fume hood18:38
azonenberg2 foot cube, 1x2 foot opening below the sash18:38
azonenberg240CFM after leaks aroudn side of the sash is about 100 linear feet per minute airflow18:38
azonenbergwell within the recommended range18:39
barrettfriedmanThat's pretty professional looking.18:39
azonenbergThx :D18:39
barrettfriedmanIs that a... toaster?18:39
azonenbergi can cook a beaker of RCA-2 on the hot plate and not smell HCl vapor at all18:39
barrettfriedmanOn the left.18:39
azonenbergIt's being stored there for now18:39
azonenbergwill be turning into a reflow oven once my thermocouple arrives18:39
barrettfriedmanWhy do you do all this?18:39
azonenbergi have a Quincy Lab oven as well but the toaster goes hotter18:39
azonenbergWhy not? :P18:39
azonenbergi'm a grad student in computer science bored with doing everythign in software18:40
azonenbergSo i started dabbling in EE on the side18:40
azonenbergbefore long i was building a fab in the living room lol18:40
barrettfriedmanYou should just join the EE department!18:40
azonenbergbarrettfriedman: my thesis work is in computer architecture and i'm taking some EE classes18:40
barrettfriedmanThen you won't have to populate your apartment with all this clutter.18:40
azonenbergi'm right on the edge18:40
azonenbergand i *want* home fab18:40
barrettfriedmanI see.18:40
azonenbergthe goal is to get it down to something you can do in a high school chemistry lab etc18:41
barrettfriedmanSo you like teaching?18:41
azonenbergsure, maybe single-die rather than full-wafer processing18:41
azonenbergand micron-scale features18:41
azonenbergi do hope to push experimentally to the 500-350nm range but i don't think i will need to go that small for any of my planned devices18:41
azonenbergMEMS is the main goal anyway since that's less sensitive to trace ion contamination18:41
azonenbergAnd i like solving complex problems :p18:42
azonenberghttp://colossus.cs.rpi.edu/pictures/2011/December/12-22-2011%20-%20lab/S7302297_sm.jpg is an action shot of me working18:43
azonenbergI try hard to keep the lab run as properly as I can, i have an MSDS book on the shelf where the landlord can find it and a written policy manual18:43
azonenbergincompatibles are isolated from each other, drip trays under all liquid storage18:44
azonenbergfull sprinkler coverage and two fire extinguishers18:44
soul-dlol hope my pic isn't  showed as "how it's not supposed to be "  :P18:44
azonenbergsoul-d: lol18:44
azonenbergI will say your lab isn't the tidiest i've seen18:45
azonenbergAnd i'm a bit OCD about mine18:45
azonenbergsince a friend got in some trouble last year with the local PD as a result of being less pedantic18:45
azonenberga friend of mine (PhD student in chemistry at my school) says my lab is cleaner than some of the ones on campus he's worked in lol18:45
soul-dyour lab is actualy yours :P18:46
azonenbergi'm even by the book about waste disposal, all of the used etchants etc are stored in plastic jars with labels as to contents and a NFPA diamond hazard label18:46
azonenbergand taken down to the county disposal site a few times a year when they get full18:46
azonenbergthat's for both the etch and the first rinse of the beaker during cleaning18:47
azonenbergthe only thing i dump down the drain is photoresist developer, which is just 1% NaOH in water18:47
azonenbergand that's after titrating to neutral with HCl18:47
azonenbergso its just salt water :p18:47
azonenbergbarrettfriedman: anyway, so back to your question18:48
azonenbergDescribe the process you're planning18:48
azonenbergyou said something about wanting to do high aspect ratio features by sputtering?18:48
barrettfriedmanazonenberg: Oh, yes. There are plenty of applications where the dimensions of a device define its behavior so I got interested in lithography as one way to establish a device's geometry. I like keeping things simple as well, so I was wondering if I could simplify the lift off process as specified by the Wikipedia article.19:17
barrettfriedmanazonenberg: After step 4 in http://upload.wikimedia.org/wikipedia/commons/b/b5/Lift-off_%28microtechnology%29_process.svg, if you can reach into the well and make some kind of measurement (electrical contact, illuminating a junction of some kind, etc.), then you don't need to worry about actually "lifting off" the photoresist layer, correct?19:21
azonenbergbarrettfriedman: There might still be residue along the sidewalls19:45
azonenbergBut all you have to do is soak it in acetone and maybe sonicate after that19:45
azonenbergIf you can do evaporation and lithography there's no reason not to do the normal liftoff process19:46
--- Mon Jan 9 201200:00

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