| azonenberg_lab | About to try BOE etching of tantalum oxide | 02:18 |
|---|---|---|
| azonenberg_lab | We'll see how well my resist handles it | 02:18 |
| azonenberg_lab | Not well :P | 02:54 |
| azonenberg_lab | Back to liftoff, there's still a few more experiments to try | 02:54 |
| CIA-67 | homecmos r103 | trunk/lithography-tests/labnotes/azonenberg_labnotes.txt | Today's lab notes | 03:27 |
| bart416 | azonenberg, you there? | 16:35 |
| azonenberg_work | bart416: Back | 19:32 |
| bart416 | How would you etch acrylic? | 19:33 |
| bart416 | Well more specifically not really etch | 19:33 |
| bart416 | I was thinking of using photoresist to do something it's not designed for | 19:33 |
| azonenberg_work | Just finished a high-vacuum evaporation run of some copper | 19:33 |
| bart416 | coat the acrylic sheet in photoresist | 19:33 |
| azonenberg_work | on glass, silicon, and Ta2O5 coated silicon | 19:33 |
| azonenberg_work | Evaporators are fun, i definitely want to get one of my own at some point | 19:33 |
| bart416 | expose the letters I want on it, remove the excess | 19:33 |
| bart416 | Heh | 19:33 |
| bart416 | Fun | 19:33 |
| bart416 | Pictures! | 19:34 |
| azonenberg_work | Still at work, when i get back i'll do some litho tests on these guys | 19:34 |
| bart416 | And then paint it | 19:34 |
| bart416 | And then remove the photoresist that was developed obviously | 19:34 |
| azonenberg_work | Interesting | 19:34 |
| bart416 | So only the letters are left | 19:34 |
| bart416 | But will it work? | 19:34 |
| azonenberg_work | Acrylic is hard to etch because its a polymer | 19:34 |
| azonenberg_work | and so is photoresist | 19:34 |
| bart416 | well it's technically not etching | 19:34 |
| azonenberg_work | You'd need to use a hardmask | 19:34 |
| bart416 | I'm using spray paint | 19:35 |
| azonenberg_work | Most spray paint contains acetone | 19:35 |
| azonenberg_work | Which will eat photoresist instantly | 19:35 |
| bart416 | yeah, that's my worry | 19:35 |
| azonenberg_work | Also, you cant strip resist with anything but acetone (which will remove paint) | 19:35 |
| azonenberg_work | If you had vacuum deposition capability it'd be easy | 19:35 |
| azonenberg_work | Evaporate copper over the plastic (assuming it was vacuum compatible) | 19:35 |
| bart416 | If it were the other way around I could make a stencil | 19:36 |
| azonenberg_work | Pattern copper with photoresist | 19:36 |
| azonenberg_work | Strip resist | 19:36 |
| azonenberg_work | Paint | 19:36 |
| bart416 | But this is near impossible >_> | 19:36 |
| azonenberg_work | And then strip copper with acid | 19:36 |
| azonenberg_work | Thing is, you'd need a LOT of copper | 19:36 |
| azonenberg_work | I dont think it would work well | 19:36 |
| bart416 | I don't have enough pure copper heh | 19:36 |
| bart416 | Could canibalise some copper tubing I pulled out of the ground during some construction work but that's about it | 19:37 |
| Laurenceb_ | another mad idea form me | 19:38 |
| Laurenceb_ | could you screen rpint using OS film? | 19:38 |
| Laurenceb_ | http://www.a2zcorp.us/store/Category.asp?Cguid={CCCB3CBA-6763-499A-8223-DDDBACB0C380}&Category=BuildingMaterials%3ACovering | 19:44 |
| Laurenceb_ | 500nm plastic film | 19:44 |
| bart416 | doubt it | 20:03 |
| Laurenceb_ | if you make the film thinner it should be possible to reduce feature size | 20:14 |
| azonenberg_work | Back | 20:17 |
| azonenberg_work | bart416: I evaporated about 1/2" of strands from a stranded wire lol | 20:17 |
| azonenberg_work | OS film? | 20:17 |
| azonenberg_work | Whats the plastic | 20:17 |
| azonenberg_work | What eats it? | 20:17 |
| Laurenceb_ | i dont know | 20:20 |
| Laurenceb_ | i was just thinking, i can screen print ~0.1mm with solder stencils | 20:21 |
| Laurenceb_ | the limiting factor is the film is approximately that thickness | 20:21 |
| Laurenceb_ | so the solder paste tends to lift off with smaller features | 20:21 |
| bart416 | Thin films like that are rather fragile | 20:22 |
| Laurenceb_ | alignment and warp would be problematic | 20:22 |
| bart416 | They'll never survive screen printing | 20:22 |
| Laurenceb_ | i dont know - it works on rc indoor planes ok | 20:22 |
| bart416 | mechanical stress on one point or or over a surface are two very different things | 20:23 |
| Laurenceb_ | hmm some features are impossible to print, come to think of it | 20:23 |
| bart416 | azonenberg, has anybody ever tried making huge semiconductors? | 20:24 |
| bart416 | I mean 5mm scale junctions :P | 20:24 |
| azonenberg_work | bart416: Jeri made transistors that were mm scale | 20:24 |
| azonenberg_work | I'm trying to shrink her process to tens of microns | 20:24 |
| azonenberg_work | iow by around 2 orders of magnitude | 20:24 |
| bart416 | silicon or just point contact? | 20:25 |
| azonenberg_work | She's made full complimentary pair CMOS inverters | 20:25 |
| azonenberg_work | two planar CMOS transistors in one die | 20:25 |
| bart416 | any link to that actually? | 20:25 |
| azonenberg_work | google "jeri ellsworth transistor" or something and you'll find hundreds of hits | 20:26 |
| azonenberg_work | That was actually the initial inspiration for this project | 20:26 |
| azonenberg_work | Though i'm now shifting my focus more toward MEMS | 20:26 |
| bart416 | So to outdo the scale I'd have to grown my own damn silicon crystal | 20:28 |
| bart416 | Challenge accepted! | 20:28 |
| bart416 | *grow | 20:28 |
| azonenberg_work | Or you can go from my process to 45nm | 20:29 |
| azonenberg_work | Its about the same order of magnitude | 20:29 |
| bart416 | Meh, I'm already writing up a proposal for a bachelors thesis about atomic scale circuits :P | 20:31 |
| bart416 | It's probably going to rejected cause it's too complicated for a bachelors or masters | 20:33 |
| azonenberg_work | lol | 20:37 |
| azonenberg_work | Do your phd on it? | 20:37 |
| bart416 | I want to go into biomedical electronics | 20:42 |
| Laurenceb_ | heh thats what im doing my phd on | 20:42 |
| Laurenceb_ | its rather bullshitty | 20:42 |
| bart416 | Laurenceb, depends on what you're specifically doing it on ;) | 20:44 |
| Laurenceb_ | im looking at perfusion monitoring | 20:44 |
| Laurenceb_ | supposed ot be | 20:44 |
| bart416 | Now that sounds boring indeed | 20:44 |
| Laurenceb_ | lol | 20:44 |
| Laurenceb_ | well its an unsolved problem | 20:44 |
| bart416 | monitoring is an unsolved problem? | 20:45 |
| bart416 | I think I've seen some devices that do that | 20:46 |
| bart416 | http://www.oxford-optronix.com/ldfmonitors.htm | 20:46 |
| Laurenceb_ | yeah but it doesnt give absolute flow | 20:46 |
| Laurenceb_ | i was looking at thermal techniques | 20:47 |
| Laurenceb_ | flexible surface probe with heated disk and outer ring | 20:47 |
| Laurenceb_ | heat to ~1C above baseline surface temperature and time power_inner/power_outer | 20:48 |
| bart416 | Please don't start about such things | 20:48 |
| Laurenceb_ | gives you bloodflow irrespective of tissue conductivity | 20:48 |
| Laurenceb_ | heh | 20:48 |
| bart416 | You'll bore me to death | 20:48 |
| Laurenceb_ | unfortunately thats what my supervisor says | 20:48 |
| bart416 | Understandable | 20:48 |
| Laurenceb_ | i think he wants me to change to another topic | 20:51 |
| Laurenceb_ | but ive spent the last 6 months making swimming reflectance PPG monitors for olympic swimmers :/ | 20:51 |
| bart416 | Also understandable | 20:51 |
| Laurenceb_ | ultra lame | 20:51 |
| bart416 | lol | 20:51 |
| bart416 | Well, you're not stealing my idea :P | 20:52 |
| Laurenceb_ | PPG with an accelerometer on the back - its based on a spin off companies device | 20:52 |
| bart416 | I doubt you have a clue on how to start with it anyway so I'm safe | 20:52 |
| Laurenceb_ | xscale based unit :S | 20:52 |
| Laurenceb_ | my supervisor is obsessed with using an accelerometer for adaptive noise cancelling to remove motion artifacts | 20:53 |
| bart416 | He's not the only one | 20:54 |
| azonenberg_work | interesting | 20:55 |
| Laurenceb_ | bart416: you had the same idea?! | 20:57 |
| bart416 | No | 20:57 |
| bart416 | I saw somebody work on something similar in the college electronics lab couple of months ago | 20:58 |
| bart416 | Also saw somebody else attempt to build a device to measure membrane thickness on the fly | 20:58 |
| Laurenceb_ | ppg with an accelerometer? | 20:59 |
| Laurenceb_ | if so i can say its been done and do something actually useful | 21:02 |
| Laurenceb_ | XD | 21:02 |
| Laurenceb_ | at least my work involves something other than sitting at a pc running matlab all day for 3/4years | 21:03 |
| Laurenceb_ | like 99% of people seem to be doing | 21:03 |
| bart416 | I'm not sure what the exact goal was | 21:04 |
| bart416 | All I know is that they stole our accelerometer we needed for another project | 21:04 |
| Laurenceb_ | heh | 21:04 |
| bart416 | And in response we gave it some tesla coil time | 21:04 |
| bart416 | And put it back in its place | 21:04 |
| Laurenceb_ | that keeps happening to me, each day something seems to be raided from my shelves | 21:04 |
| bart416 | I wonder why it suddenly stopped working | 21:05 |
| Laurenceb_ | heh | 21:05 |
| bart416 | We addopted a new policy, lock it in a metal container (wood and plastic they'll just cut through) or solder it to a board | 21:05 |
| bart416 | And never use sockets | 21:05 |
| Laurenceb_ | i refuse to run matlab at all :P | 21:05 |
| azonenberg_work | Lol | 21:06 |
| Laurenceb_ | when i was a physics undergrad i saw a grad student trying to simulate a tokamak in matlab | 21:07 |
| azonenberg_work | o_O | 21:07 |
| azonenberg_work | Bet it didnt go too well | 21:07 |
| bart416 | simulate a tokamak in matlab??? o_O | 21:07 |
| Laurenceb_ | i spent a while looking at NMR flowmeters, but it looks like the noise is too high | 21:10 |
| Laurenceb_ | that would have been fun to try and build | 21:10 |
| Laurenceb_ | so yeah my next meeting with supervisor will probably involve a change of research topic | 21:18 |
| bart416 | You know, trying to remove the noise would be a nice subject | 21:21 |
| Laurenceb_ | nmr mouse.de or something | 21:22 |
| azonenberg_work | You want to use NMR for what? | 21:22 |
| Laurenceb_ | flowmetery | 21:23 |
| --- Fri Jul 22 2011 | 00:00 | |
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