#homecmos IRC log for Sunday, 2013-02-10

B0101I was thinking about a way to produce HF, I think we can make HF by this reaction: CaF2 + H2SO4 --> CaSO4 + 2 HF, but then I can't find a suitable reaction vessel00:10
Sync_get stainless pickling solution00:11
Sync_or let someone buy you HF that is able to procure it00:11
B0101We can procure HF (only through drain cleaners), but the solution has a lot of impurities in it00:14
berndjB0101, there was a guy on the amateur telescope making list who said he used CaF2 + HCl to help with grinding00:14
Sync_that's what I meant, try to get it pure00:14
Sync_maybe in glass etching solution00:14
berndjand yes, AFAIK CaF2 + H2SO4 is the primary way that HF gets produced00:15
berndj(or was that for F2 itself, but that's a small hop from there to HF)00:15
berndjB0101, what do you mean by "suitable reaction vessel"?00:16
B0101berndj: I wanted to make HF, but I know I cannot use glass or metals00:17
berndjwhy not metals?00:17
berndjHF should passivize them00:17
B0101I was thinking HF would react with the metals, but then for now, I'd follow Sync_'s advice and I would try glass etching chemicals first00:18
berndjit's the H2SO4 that would attack the metal00:18
B0101berndj: Copper? will it work?00:19
berndjand i have to wonder if glass is "good enough" if not "imperfect"00:19
berndjwhat concentration of H2SO4 will you use? that could make all the difference00:19
berndjB0101, AFAIK HF gets transported in big nickel (or nickel-lined; that stuff is expensive) tanks00:20
berndjmaybe stainless steel is close enough? surely this is something you can figure out empirically00:21
Sync_plastic containers also work00:21
Sync_stainless also works00:21
berndjyeah, polyethylene is ok with HF00:21
Sync_but it depends on concentration00:21
B0101berndj: I am thinking of taking copper sulfate and performing electrolysis with a platinum and copper anodes and cathodes to get H2SO4, then boiling it down to get pure H2SO$00:21
berndjnot sure about H2SO4 though! HF + H2SO4 is a nasty combination!00:22
berndjisn't that called "piranha water"?00:22
Sync_that is one dangerous reaction to do B010100:22
Sync_I'd rater much not be there when it happens00:22
berndji don't think H2SO4 works like that - "boiling it down"00:22
berndjyou get H2O boiling off, sure, but also SO3 gas00:23
berndjpersonally i'd go the other way, and make H2SO4 from SO3 - but turning SO2 into SO3 is the step i'm less confident about00:24
berndjB0101, can you get HF and fairly concentrated H2SO4 of basically any purity?00:25
B0101If I am buyinf for my home lab, I only can get maximum 10% of H2SO4 and HF from drain cleaners (purity not known)00:26
berndjif so, maybe use the impure HF to passivize your metal reaction vessel, then do the CF2 + H2SO4 trick and let the evolving HF gas bubble through water00:26
Sync_h2so4 is found in battery acid00:26
Sync_usually pretty clean00:26
berndjand pretty concentrated too, right?00:26
Sync_also getting that stuff metal free is an issue, I guess it is not much worth if you have HF afterall when it is still contaminated00:27
berndjor don't bother passivating, just sacrifice a reaction vessel when it's too damaged00:27
berndjSync_: that's why i suggest bubbling the gas through water; metal ions should stay behind, i'd think00:28
Sync_we are talking ppb here00:29
berndjoooh, i didn't know that :)00:29
berndji thought we were doing kitchen chemistry where ppt would be good enough!00:30
Sync_afterall this is #homecmos :P00:30
Sync_yeah I guess it'd work00:30
Sync_but really00:30
Sync_that is far too dangerous00:30
berndjazonenberg seems to think it's #homemems, tsk tsk00:30
Sync_making HF from scratch is a huge issue00:30
berndjof course!00:31
berndjB0101: when you do CaF2 + H2SO4, don't sniff the beaker! :D00:32
Sync_looking at the safety instructions at work I'd really not want to go down that road00:32
Sync_using HF is fine but eh. making it00:32
B0101I remember that some people purify HCl by placing 2 containers in a tank (1 filled with water and another filled with HCl) , sealing it and waiting about 2 weeks to get pure acid00:35
B0101I'm not sure if it works for HF00:35
berndjB0101, it would depend on which impurities you have, and their vapour pressures and evaporation rates00:36
B0101I am not sure if we can make a plastic condenser unit00:45
B0101anyway, how can you remove surfacants from NaOH?00:47
Sync_buying it pure from the hobby pcb shop or photographers supply00:49
Action: B0101 thinks that quite a lot of chemical she owns are from drain cleaners or self synthesized00:52
B0101Sync_: Photography shops here doesn't carry NaOH00:53
Sync_I usually try to buy technical grad or better depending on what I need00:53
B0101If the photogrpahy shops or electronics shops have NaOH, I wouldn't try getting NaOH from drain cleaners00:55
Sync_where do you live that procuring chemicals is even more of an issue than in germany?00:56
Sync_I'd think that getting chemicals there would be easier00:57
B0101for professional labs, yes, home labs? no00:58
B0101Ferric Chloride is controlled here too!01:00
Sync_that's interesting01:00
B0101here is the list of all controlled chemicals in my country: http://app2.nea.gov.sg/data/cmsresource/20090629934087284535.pdf01:02
B0101quite alot of common chemical appears in the list01:03
B0101I think even NaOH, KOH, HCl and HNO3 are included in there01:09
Sync_naoh and koh is on there01:09
B0101sulfuric acid too01:10
B0101I think you get the idea now01:12
Sync_that is messed up01:12
azonenbergB0101: anionic surfactants in >5% concentration - aka any strong detergent01:16
azonenbergFeCl3 is01:18
azonenbergAcetic acid, but only >80%01:18
azonenbergHCl at >9%? o_O01:18
azonenbergHF at >2% i can somewhat understand01:19
azonenbergHNO3 >9% o_O01:20
azonenbergB0101: So what does it take to get the things on that list?01:20
B0101Black market01:21
azonenbergwait, they cant be legally obtained at all?01:21
B0101for personal use, no01:21
Sync_yeah azonenberg it is pathetic01:22
Sync_NaOH and KOH is on there01:22
azonenbergthats ridiculous01:23
azonenbergbasically every possible drain cleaner is01:23
azonenbergH2SO4 too01:23
B0101I have talked to a friend who is a police officer, he says that the rules here are actually set to prevent people from home experimentation, not anything else01:27
azonenberglol what?01:27
azonenbergi was going to say most of those things didnt seem to have obvious drug/explosives uses01:28
B0101Because we have big science companies like GlaxoSmithKline and others, and he says that they're afraid that some home experimenter will discover something big, which may put those companies out of business here01:29
azonenbergOk, one more reason not to move to singapore (not that i was planning to do so anyway)01:29
B0101That's why people smuggle chemicals in here01:32
B0101And I have to buy from the black market or people who smuggle them in01:33
B0101Funny thing is, Singapore tries to portray itself as a science and tech hub01:35
B0101its absolutely crazy!01:36
B0101In my head: a little voice screams: I want to do science! but then I can't because of all these rules01:42
Sync_yeah reason to move abroad01:43
superkuhI had a fire marshal tell me it was illegal to have a couple gallons of battery acid in my apartment. (USA)01:43
superkuhHe made me "dispose" of it with a commercial company. >$500 and that was with huge discounts from the company pickup guy who was actually very nice.01:44
B0101I have no idea what to say...01:45
Sync_yeah getting basic acids has been getting easier here since again01:45
B0101I have been subjected to random checks at train stations for idk what reason01:56
B0101I even think of getting a bike to go to work01:57
B0101I don't want to be checked every time at train stations01:57
B0101I guess I am moving out of this country01:59
Sync_that is a good idea01:59
B0101I'm not sure where is a good place though02:00
B0101I think I want to go somewhere (thailand maybe) and build a underground lab02:02
B0101Is there any film material that turns dark when electricity is applied?02:10
soul-ddonno have read on stuff like that  in combination with windows02:13
soul-dbut that probably was an article floating by  in the line of http://en.wikipedia.org/wiki/Smart_glass02:17
B0101hmm, I wonder if such technology can be used in litho processes?02:22
B0101If we could control how opaque the glass becomes and at different location to form patterns02:24
B0101we may be able to make so called reusable photomasks02:24
nmz787azonenberg: is mtixtl better than universitywafers on price?09:17
nmz787azonenberg: do you know where i can get FDTS or something like it? i saw that link earlier for the cheap HMDS09:49
B0101hey, anyone knows of any use for 1 inch wafers?10:54
nmz787microfluidics platform11:40
nmz787B0101: got a cheap source?11:40
B0101cheap source. but only ships to asia pacific countries11:41
B0101the 1 inch wafers are cheap11:42
B0101but the rest may cost a few hundred dollars11:42
azonenbergnmz787: university wafers is usually a better price in bulk12:21
azonenbergbut has high minimum orders12:21
azonenbergmost of the time you can't buy only one wafer12:21
azonenbergMTI will sell single-unit quantity12:21
nmz787azonenberg: i can only really find fdts from gelest12:36
azonenbergfdts = ?12:36
azonenbergNot familiar with it12:37
azonenbergi see a silane group but thats it12:37
azonenbergwhat does it do?12:37
nmz787provides a liftoff layer12:37
nmz787azonenberg: http://nathanmccorkle.com/pdf/Improved%20anti-stiction%20coating%20of%20SU-8%20molds.pdf12:43
soul-d:')  comments are silly12:48
soul-d"can't we do this bigger"12:48
soul-dthink their missing the point12:48
azonenbergPhotoresist developing seems to be one of the very few wet processes still in use in modern high-end litho12:54
azonenbergHas there been any work in dry (vapor / plasma) developable photoresist chemistries?12:54
azonenbergI see one patent from 1980 but not very much work http://www.google.com/patents?hl=en&lr=&vid=USPAT4241165&id=z2ErAAAAEBAJ&oi=fnd&dq=photoresist+development+by+plasma&printsec=abstract#v=onepage&q=photoresist%20development%20by%20plasma&f=false12:57
soul-donly in my imagination wich i can assure you is of little help in reality12:57
Sync_azonenberg: iirc there is something done like that12:59
Sync_but only experimental12:59
azonenbergSync_: yeah, i was wondering what the reason for that was12:59
azonenbergjudging by how hard the semi world has been trying to eliminate wet processing12:59
soul-dlike there is the copper reaction  common in chemistry with sugar   so i was thinking maybe one could grow copper stuff (in particular those the nm formation where research is being done on )12:59
Sync_litho is the singlemost expensive step in CMOS12:59
azonenbergi'm just surprised this process stayed wet13:00
Sync_and there are not alot of companies making equipment13:00
azonenbergSync_: doesn't that mean it would be the one people try hardest to optimize?13:00
azonenbergYou can use the same exposure system13:00
Sync_yeah but I guess it did not pan out13:00
azonenbergyou'd just need a different resist chemistry13:00
soul-dmaybe wet is less suseptable to conatmination ?13:00
soul-dlike dust ?13:01
azonenbergSeems unlikely13:01
azonenbergnormally dry processes are preferred for better uniformity etc13:01
Sync_well probably the fear is adopting something that is not tested very good13:01
Sync_because fabs are now getting so expensive that they have to be shared by different vendors13:02
soul-dmmm those fabs are second in research   they are ones who apply13:02
soul-ddoubt asml  does sharing13:03
azonenbergyeah, looks like it got studied a bit during the 1980s13:06
azonenbergbut pretty much dropped since then13:07
soul-dyup  the example process is something typical happening in you kitchen13:11
soul-di thats what i imagen  how your breakfast recipe's look like :P13:11
soul-dhttp://i.imgur.com/MbSZbbD.png   although change   y  to  "imagened iq " and x  as  time spend in #homecmos :P13:17
B0101hi, is there anyway to remove photoresist from copper PCB boards and reuse it for other uses?13:25
B0101so once photoresist is evaporated it can no longer be extracted?13:38
Sync_you can remove it with acetone13:40
Sync_but you cannot reuse it13:40
berndjzomglol @ GSK being afraid of home experimenters15:28
Sync_I know someone at GSK who refuses to take their meds16:16
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