18:35 <barrettfriedman> Hello.

18:35 <azonenberg> hi :)

18:35 <azonenberg> I'm serious about the "home" part btw lol

18:36 <barrettfriedman> I evidently need more sleep. I misread for a second... "Hebrew" CMOS and MEMS foundry design

18:36 <azonenberg> Mostly been pushing lithography, i have 20 micron patterning working reliably and am working on shrinking to 2ish using commercially made 8000DPI film masks

18:37 <azonenberg> i have the beginnings of a vacuum setup but still use an evaporator on campus for doing film deposition

18:37 <azonenberg> all of the spin coating, lithography, and etching are in my home lab

18:37 <barrettfriedman> Keeping it simple I see.

18:37 <azonenberg> Admittedly my lab is a bit better equipped then your average hobbyist http://imgur.com/a/Y3m0L#3

18:38 <azonenberg> yes that's a 4" wafer prober on the right

18:38 <barrettfriedman> How are you dealing with the vapors involved in etching processes?

18:38 <azonenberg> http://imgur.com/a/Y3m0L#5

18:38 <azonenberg> Homebrew fume hood

18:38 <azonenberg> 2 foot cube, 1x2 foot opening below the sash

18:38 <azonenberg> 240CFM after leaks aroudn side of the sash is about 100 linear feet per minute airflow

18:39 <azonenberg> well within the recommended range

18:39 <barrettfriedman> That's pretty professional looking.

18:39 <azonenberg> Thx :D

18:39 <barrettfriedman> Is that a... toaster?

18:39 <azonenberg> i can cook a beaker of RCA-2 on the hot plate and not smell HCl vapor at all

18:39 <barrettfriedman> http://imgur.com/a/Y3m0L#5

18:39 <barrettfriedman> On the left.

18:39 <azonenberg> Yes

18:39 <azonenberg> It's being stored there for now

18:39 <azonenberg> will be turning into a reflow oven once my thermocouple arrives

18:39 <barrettfriedman> Why do you do all this?

18:39 <azonenberg> i have a Quincy Lab oven as well but the toaster goes hotter

18:39 <azonenberg> Why not? :P

18:40 <azonenberg> i'm a grad student in computer science bored with doing everythign in software

18:40 <azonenberg> So i started dabbling in EE on the side

18:40 <azonenberg> before long i was building a fab in the living room lol

18:40 <barrettfriedman> You should just join the EE department!

18:40 <azonenberg> barrettfriedman: my thesis work is in computer architecture and i'm taking some EE classes

18:40 <barrettfriedman> Then you won't have to populate your apartment with all this clutter.

18:40 <azonenberg> i'm right on the edge

18:40 <azonenberg> and i *want* home fab

18:40 <barrettfriedman> I see.

18:41 <azonenberg> the goal is to get it down to something you can do in a high school chemistry lab etc

18:41 <barrettfriedman> So you like teaching?

18:41 <azonenberg> sure, maybe single-die rather than full-wafer processing

18:41 <azonenberg> and micron-scale features

18:41 <azonenberg> i 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 devices

18:41 <azonenberg> MEMS is the main goal anyway since that's less sensitive to trace ion contamination

18:42 <azonenberg> And i like solving complex problems :p

18:43 <azonenberg> http://colossus.cs.rpi.edu/pictures/2011/December/12-22-2011%20-%20lab/S7302297_sm.jpg is an action shot of me working

18:43 <azonenberg> I 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 manual

18:44 <azonenberg> incompatibles are isolated from each other, drip trays under all liquid storage

18:44 <azonenberg> full sprinkler coverage and two fire extinguishers

18:44 <soul-d> lol hope my pic isn't showed as "how it's not supposed to be " :P

18:44 <azonenberg> soul-d: lol

18:45 <azonenberg> I will say your lab isn't the tidiest i've seen

18:45 <azonenberg> And i'm a bit OCD about mine

18:45 <azonenberg> since a friend got in some trouble last year with the local PD as a result of being less pedantic

18:45 <azonenberg> a 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 lol

18:46 <soul-d> your lab is actualy yours :P

18:46 <azonenberg> i'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 label

18:46 <azonenberg> and taken down to the county disposal site a few times a year when they get full

18:47 <azonenberg> that's for both the etch and the first rinse of the beaker during cleaning

18:47 <azonenberg> the only thing i dump down the drain is photoresist developer, which is just 1% NaOH in water

18:47 <azonenberg> and that's after titrating to neutral with HCl

18:47 <azonenberg> so its just salt water :p

18:48 <azonenberg> barrettfriedman: anyway, so back to your question

18:48 <azonenberg> Describe the process you're planning

18:48 <azonenberg> you said something about wanting to do high aspect ratio features by sputtering?

19:18 <barrettfriedman> azonenberg: 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.

19:21 <barrettfriedman> azonenberg: 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?

19:45 <azonenberg> barrettfriedman: There might still be residue along the sidewalls

19:45 <azonenberg> But all you have to do is soak it in acetone and maybe sonicate after that

19:46 <azonenberg> If you can do evaporation and lithography there's no reason not to do the normal liftoff process