| Sync_ | what's so bad about it, once it's gone it's gone | 00:00 |
|---|---|---|
| Sync_ | use it while we can | 00:00 |
| Sync_ | huh 10" conflat blanks are ... spendy | 00:01 |
| diginet | because we lose a tonne of things like MRIs, particle accelerators, cryogenics in general, etc | 00:42 |
| Sync_ | I guess there will be an effort to make better superconducting magnets that work at LN2 temperatures | 00:45 |
| diginet | it's not the critical temperature that is the issue, the superconductors which need LHe have a much higher critical field, and also have much better mechanical properties | 01:20 |
| Sync_ | yes, but that is just an engineering problem ;) | 01:21 |
| diginet | the latter yes, but not the former | 01:22 |
| diginet | although, one potential option could be MgB2, which only needs LH2 | 01:22 |
| Sync_ | I guess if we really run out sensors will have improved | 01:24 |
| Sync_ | we're currently also making a mass spec for breathing air | 01:24 |
| Sync_ | to detect trace acetone | 01:24 |
| diginet | azonenberg: are you around? | 01:25 |
| Sync_ | which appears in a few ppm just before you have a sugar shock or epileptic seizure | 01:26 |
| diginet | I was wondering, what is the DPI on photomasks generally? Because I wondering, would FLCDs work as a sort of digital photomask? They have ridiculously high pixel density | 01:26 |
| Sync_ | but the vacuum system is the main problem | 01:26 |
| Sync_ | good question diginet | 01:32 |
| diginet | if an FLCD could work as a photomask, that would be my number one choice, if not, then e-beam | 01:32 |
| Sync_ | ebeam would be mine because that is pretty easy to make | 01:33 |
| diginet | sure, but vacuum | 01:35 |
| diginet | then again, the mask is just PMMA in a solvent, which is absurdly cheap/simple/safe | 01:35 |
| Sync_ | vacuum is easy | 01:35 |
| diginet | is it though? you need a pretty hard vacuum for e beam | 01:39 |
| Sync_ | yeah but getting in the 10^-7mbar range is not too bad | 01:40 |
| Sync_ | which is acceptable for ebeam | 01:40 |
| diginet | well, you can cannibalize a rotary vane from an old fridge for the first stage, and an ion beam pump might be DIYable | 01:40 |
| Sync_ | not really | 01:41 |
| Sync_ | that will not be sufficient | 01:41 |
| diginet | I don't know enough about them, but I wonder if a turbomolecular pump could be made from a turbocharger for a car | 01:41 |
| Sync_ | just get a two stage rotary and a turbo | 01:41 |
| diginet | turbos at least $5k | 01:41 |
| diginet | I don't call that DIYable, at all | 01:41 |
| diginet | and they're insanely fragile and tempermental | 01:41 |
| Sync_ | then why do I have 7 rotaries and 2 turbos? | 01:41 |
| Sync_ | somewhere there should also be a tsp and an ion pump | 01:42 |
| diginet | you do? | 01:42 |
| Sync_ | yes | 01:42 |
| diginet | where did you get them? | 01:42 |
| Sync_ | mostly ebay | 01:42 |
| Sync_ | or fron work | 01:42 |
| Sync_ | ~from even | 01:42 |
| diginet | how much? | 01:43 |
| Sync_ | my first rotary turbo set was 450¬ | 01:43 |
| diginet | hmm | 01:43 |
| diginet | still pricey though | 01:43 |
| Sync_ | thinking about getting a cryo pump | 01:43 |
| diginet | cryo pumps could be DIYed I think | 01:43 |
| diginet | it's just a stirling engine in reverse | 01:43 |
| Sync_ | yes | 01:44 |
| Sync_ | but it is quite a challenge to get it working at 12K | 01:45 |
| Sync_ | it is easier just to buy one | 01:45 |
| Sync_ | nobody said it would be cheap but it is not really expensive | 01:47 |
| diginet | do rotaries have oil? | 01:47 |
| Sync_ | yes | 01:47 |
| Sync_ | they have to | 01:47 |
| diginet | are there any oil-less first stage pumps? | 01:48 |
| Sync_ | yes membrane pumps | 01:48 |
| Sync_ | why do you want to go oilless? | 01:48 |
| Sync_ | the problem with membrane forepumps is low throughput and the turbo needs to be a modern hybrid one | 01:49 |
| diginet | because oil creates a lot of problems | 01:49 |
| diginet | what about sorption pumps? they seem rather simple | 01:50 |
| Sync_ | yes but you need to have access to ln2 | 01:51 |
| Sync_ | oil isn't too much of a problem | 01:51 |
| diginet | LN2 isn't either | 01:51 |
| Sync_ | yeah but you need a supply of it | 01:51 |
| diginet | LN2 is cheaper than water | 01:51 |
| Sync_ | oil just sits in the pump | 01:51 |
| diginet | I'm building an air liquefaction machine | 01:51 |
| diginet | the problem is when it gets into the chamber, which is especially a problem for semiconductors | 01:52 |
| Sync_ | yes for ultra modern devices and mass production it is an issue | 01:52 |
| Sync_ | but not for a hobbyist or research | 01:52 |
| Sync_ | two of our evap chambers are oil pumped and it is all good | 01:53 |
| Sync_ | I'd have a scroll pump here just in case tho | 01:53 |
| diginet | yeah, those are cool | 01:54 |
| Sync_ | again, you complain about vacuum being expensive and then complain about the cheapest way to get there by using oil sealed rotaries... | 01:54 |
| Sync_ | it is much less a problem than one would think | 01:55 |
| Sync_ | you can even inject nitrogen into the forepump line to keep it at an elevated pressure | 01:55 |
| diginet | sorry, I didn't mean to complain, :P | 01:56 |
| Sync_ | what approach are you using for your liquifier? | 01:56 |
| diginet | hampson-linde cycle, with pre-cooling | 01:56 |
| diginet | it's not the most efficient, but it's not so bad | 01:57 |
| Sync_ | ah lame | 01:57 |
| diginet | why do you say that? | 01:57 |
| Sync_ | because that's the easy way | 01:58 |
| diginet | what would you propose using then? reverse-brayton? | 01:59 |
| Sync_ | I bought a high pressure compressor for that but then changed my mind, an autocascading precooler is just easier | 01:59 |
| Sync_ | but that project is on ice since I just can open the ln2 tap at work | 02:00 |
| diginet | hmm, is a cascade cooler more efficient? | 02:01 |
| Sync_ | that really depends | 02:02 |
| diginet | but you say cascade is easier? | 02:03 |
| Sync_ | we have a small ln2 generator in one lab because getting a ln2 line installed is too expensive and it uses a cascade | 02:03 |
| Sync_ | well, you only have to get the gas mix right | 02:03 |
| Sync_ | which is not too bad | 02:03 |
| diginet | I guess that makes sense considering there is no compressor (the compressor is definitely expensive) | 02:03 |
| Sync_ | yes no dicking around with high pressure air too | 02:04 |
| diginet | indeed | 02:04 |
| diginet | one thing I've considered is starting it off with a membrane to at least eliminate some of the O2, I'd rather not have to deal with LOX | 02:04 |
| Sync_ | lox is fun | 02:05 |
| Sync_ | it is also blue :D | 02:05 |
| diginet | sure, but it's explosive and dangerous | 02:05 |
| diginet | but it is pretty, no denying that | 02:05 |
| Sync_ | it is only supporting combustion very well so just keep it away from combustibles | 02:06 |
| Sync_ | it is also quite magnetic | 02:06 |
| Sync_ | which is also fun to demonstrate | 02:06 |
| diginet | yes! I've seen that before, well, diamagnetic technically | 02:07 |
| Sync_ | yeah | 02:07 |
| Sync_ | you can have very good fun burning things quite fast with lox | 02:07 |
| diginet | this is insane, but what I really want is some DIY Ar | 02:08 |
| diginet | that stuff is pricey (even though it shouldn't be) | 02:08 |
| Sync_ | huh | 02:08 |
| Sync_ | 20l bottle refill is around 40¬ | 02:08 |
| Sync_ | which is quite good | 02:10 |
| diginet | that's almost $70, not cheap IMO | 02:10 |
| Sync_ | ??? | 02:11 |
| Sync_ | you're getting a gas, known to be oil free, 4 9s or better in quality | 02:11 |
| Sync_ | I mean really, that's cheaper than you could do it | 02:11 |
| diginet | I don't need 4N though | 02:12 |
| Sync_ | what do you want to use it for? | 02:12 |
| diginet | glovebox | 02:13 |
| diginet | problem is purge and fill means I need several times the volume of the chamber for one session | 02:14 |
| Sync_ | use a load lock | 02:14 |
| Sync_ | a 50l bottle of n2 would probably be the easiest | 02:15 |
| Sync_ | yeah 50l n2 is +-50¬ per fill | 02:19 |
| Sync_ | for a continious application that'd be quite a lot but then n2 concentrators are quite spendy | 02:20 |
| azonenberg | diginet: For SEM coating you can sputter/evaporate almost anything | 10:52 |
| azonenberg | sputtered Au can be done with a less high vacuum and cheaper equipment | 10:52 |
| azonenberg | as with sputtered Pt | 10:52 |
| azonenberg | with deeper vacuum you can evaporate C but that doesnt work well on samples with complex topography | 10:52 |
| nmz787 | diginet: what's an FLCD? | 11:30 |
| B0101 | azonenberg: do you test your wafer conductivity when you get them? | 12:17 |
| azonenberg | B0101: I have not done any semiconductor work per se | 12:17 |
| azonenberg | so i've never needed to | 12:17 |
| azonenberg | all of my fab to date has been purely mechanical | 12:17 |
| azonenberg | lithography testing, MEMS, etc | 12:18 |
| B0101 | oh | 12:18 |
| azonenberg | That way i dont care about metal contamination ;) | 12:41 |
| B0101 | hehehe | 12:43 |
| B0101 | I may sound crazy, but do you think you can grow oxide layers using a normal oven? | 12:49 |
| B0101 | I want to pump steam into a normal oven, but I think it will be a slower process than if I were to use a kiln at temperatures above 1000 deg C, am I right? | 12:51 |
| azonenberg | It's exponential | 12:53 |
| azonenberg | You will get oxide growth even at room temperature | 12:53 |
| azonenberg | But it wont be usefully fast below 600C or so | 12:53 |
| azonenberg | I would suggest you look into spin-on glass if you want to avoid thermal oxidation | 12:53 |
| diginet | FLCD is ferrofluid liquid crystal display | 13:53 |
| diginet | so I've been working on an intersting-ish side project, basically, DIY e-paper | 14:03 |
| azonenberg | ooh | 14:03 |
| azonenberg | how far have you gotten? | 14:03 |
| diginet | pretty far actually | 14:03 |
| diginet | it is surprisingly simple | 14:03 |
| diginet | it uses electrochromism instead of electrophoresis | 14:03 |
| diginet | prussian blue pigment sandwich between ZnO:Al coated glass (patterned of course) | 14:04 |
| azonenberg | I guess the low resolution but cheap option | 14:04 |
| diginet | or PEDOT | 14:04 |
| azonenberg | would be thermochromism :P | 14:04 |
| diginet | heh | 14:04 |
| azonenberg | nice little grid of heating elements | 14:04 |
| azonenberg | backing a thermochromic dye on a plate | 14:05 |
| azonenberg | refresh rates on the order of 0.5 Hz | 14:05 |
| azonenberg | massive power consumption | 14:05 |
| azonenberg | resolution of 0.5cm or so | 14:05 |
| diginet | well prussian blue is insanely cheap, and PEDOT and/or ZnO:Al are as well | 14:05 |
| azonenberg | Sounds interesting | 14:05 |
| azonenberg | Why ZnO/Al instead of ITO? | 14:05 |
| diginet | because ITO is stupidly pricy | 14:05 |
| diginet | and I prefer to use sustainable materials | 14:05 |
| azonenberg | Hmm, how about like sputtered Au or something | 14:05 |
| azonenberg | a few nm of it cant be that expensive | 14:06 |
| diginet | wouldn't work, too thin | 14:06 |
| diginet | thus too high resistivity | 14:06 |
| azonenberg | As in, to be thick enough to have good resistivity it'd be opaque? | 14:06 |
| diginet | yeah | 14:06 |
| azonenberg | Hmm | 14:06 |
| diginet | AZO is already in use though, it's much more common in the solar cell industry | 14:07 |
| azonenberg | I see | 14:07 |
| diginet | the only problem is that it needs a moisture barrier because it is more susceptible to atmospheric water vapour than ITO | 14:07 |
| azonenberg | Yeah, i was just reading that | 14:07 |
| diginet | seriously though, ITO is a thorn in the side of the display industry | 14:08 |
| azonenberg | How about just spin-on glass? | 14:08 |
| diginet | yeah, or acrylic or whatever | 14:08 |
| azonenberg | Well i was thinking | 14:08 |
| azonenberg | ZnO/Al film | 14:08 |
| azonenberg | pattern it | 14:08 |
| azonenberg | coat the whole surface with a transparent insulator of some sort, say SOG or reactive sputtered SiO2 | 14:08 |
| azonenberg | Then etch windows in the glass where you want "bond pads" | 14:09 |
| azonenberg | and put down, say, a thick aluminum or copper layer | 14:09 |
| diginet | I think what is often used is PEDOT, which is of course also conductive, and protects it (where you need contact with the electrolyte) | 14:09 |
| diginet | PEDOT:PSS is interesting, very easy to make, the problem is it only has about 1/10 the conductivity as ITO | 14:10 |
| diginet | that being said, electrochromics are bistable, so maybe it doesn't matter | 14:10 |
| diginet | you know what's cool though? prussian blue is the same pigment used in blueprints/cyanotypes, so this would be literally, "e-blueprints" | 14:11 |
| azonenberg | lol | 14:11 |
| diginet | e-ink is amusing, because it's /way/ over-engineered | 14:12 |
| diginet | there have been much simpler options around for a long time | 14:12 |
| diginet | the best part is that the bistability means no need for active matrix | 14:14 |
| azonenberg | ooh | 14:16 |
| diginet | what I don't understand is, considering how simple this stuff is, why it isn't in use | 14:17 |
| azonenberg | well the wiki article suggests that AZO is difficult to etch | 14:18 |
| azonenberg | You might want to consider a lift-off process | 14:18 |
| azonenberg | Not that those have great resolution either | 14:18 |
| azonenberg | How is it normally deposited - sputtering? | 14:19 |
| diginet | no, not AZO, i mean electrochromics | 14:19 |
| azonenberg | And is that reactive sputtering of an Al/Zn target in Ar+O2? | 14:19 |
| azonenberg | oh | 14:19 |
| diginet | even using ITO | 14:19 |
| diginet | I mean, electrochromics are absurdly simple | 14:19 |
| diginet | azonenberg: my preference is sol-gel, which has been demonstrated | 14:20 |
| azonenberg | http://pubs.acs.org/doi/abs/10.1021/cm902069k | 14:20 |
| diginet | although I'm still considering PEDOT | 14:20 |
| azonenberg | black to transmissive | 14:20 |
| azonenberg | 2009 | 14:20 |
| diginet | interesting | 14:21 |
| diginet | uses a PEDOT relative as well | 14:21 |
| azonenberg | How about switching speed | 14:22 |
| diginet | can be down to 200 milliseconds | 14:22 |
| azonenberg | "Recent advancements in modified porous nano-crystalline films have enabled the creation of electrochromic display. The single substrate display structure consists of several stacked porous layers printed on top of each other on a substrate modified with a transparent conductor (such as ITO or PEDOT:PSS)." | 14:22 |
| azonenberg | Looks like it's an ongoing research problem | 14:22 |
| Sync_ | hmm yeah | 14:37 |
| B0101 | Anyone here knows about optics? | 22:47 |
| Sync_ | just ask | 22:50 |
| B0101 | I want to know how to set up a proper system in which take a photomask and shrink the pattern down for exposure | 22:53 |
| --- Tue Feb 19 2013 | 00:00 | |
Generated by irclog2html.py 2.9.2 by Marius Gedminas - find it at mg.pov.lt!