#homecmos IRC log for Sunday, 2011-06-19

wolfspraulhi qi-bot02:19
azonenbergwolfspraul: is that your CIA bot?02:19
wolfspraulno irc logging02:19
wolfspraulwait I need to test a bit more02:19
azonenbergAh02:20
azonenbergLet me work on setting up CIA then02:21
B0101how do you add the CIA bot?02:31
azonenbergB0101: cia.vc02:31
azonenbergI'm still configuring it02:31
azonenbergThere we go02:36
azonenbergAnybody here interested in getting added to the Google Code project? You'll start out as a contributor plus edit permissions on the wiki02:39
azonenbergjust send me your googlecode email address02:39
B0101Can I do it?02:41
wolfspraulazonenberg: I think it works http://en.qi-hardware.com/homecmos-logs/02:41
wolfspraulsearch works too02:41
azonenbergB0101: can you join the googlecode project? Sure, PM me your googlecode email02:43
B0101Ok... Gimme a second02:44
azonenbergwolfspraul: hmm... this means my email shows up in logs *wonders if there's a way to spamproof this*02:46
wolfspraulsorry got disconnected02:49
wolfspraulazonenberg: those logs are updated every 30 minutes02:50
azonenbergah02:50
azonenbergCan you clear them? CIA dumped an email address i'd rather not get too spammed into the channel02:50
azonenbergworking on a new filter that'll spam-sanitize emails02:50
wolfspraulno need to do more instantaneous, I think. From my experience so far, the most important is a good search feature, and that works.02:50
wolfspraulsure, will do02:50
wolfspraulas for the logs themselves, I can totally give you server access and you can do with them whatever you like02:50
wolfspraulso later we can always cleanup, move all to one domain, or whatever you want02:51
wolfspraulI'm not an information hoarder :-)02:51
azonenbergLol02:51
azonenbergYeah, as of now i just want the info to be out there where people can find it02:51
wolfsprauljust email me your public key (wolfgang@sharism.cc)02:51
azonenbergSSH or GPG?02:51
wolfspraulssh02:52
wolfspraulso I think 'search' is what most people use02:52
wolfspraulit works quite well02:52
azonenbergYeah, agreed02:52
azonenbergwolfspraul: For now i can't see any easy way of doing search-and-replace on usernames, and since googlecode insists on using emails as usernames i'll just not include the author in the CIA message02:55
azonenbergjust the files and log message02:55
berndj"pyrex" isn't pyrex anymore; "pyrex" is just a trademark, and modern cookware labelled "pyrex" is no longer borosilicate, but just tempered soda-lime glass02:55
azonenbergberndj: Interesting02:55
azonenbergI knew pyrex was a trademark but i just assumed it was all borosilicate02:55
azonenbergMost of my actual labware is Borosil brand02:56
azonenbergAnd i know for a fact that's borosilicate still :P02:56
CIA-67[removed] * r78 /wiki/FreeEDATools.wiki: Created wiki page through web user interface.02:57
azonenbergI thought i fixed that, hmm02:57
berndjlabware would typically be borosilicate, i imagine02:58
azonenbergLet's try this again...02:59
berndjamateur telescope makers greatly regret the decreasing availability of borosilicate02:59
CIA-6779 wiki/FreeEDATools.wiki Dummy commit to test new CIA bot configuration02:59
wolfspraulazonenberg: I'll clean it later if you don't mind02:59
wolfspraulduring the day the log file is open, so I have to restart the bot (don't know better)03:00
azonenbergNo rush, i just dont want to leave it up there for a long time to get spidered03:00
wolfspraulI'll go through tomorrow and remove the address...03:00
azonenbergOk, thx03:00
CIA-67homecmos r80 | wiki/FreeEDATools.wiki | Edited wiki page FreeEDATools through web user interface.03:01
azonenbergThere we go03:01
azonenbergB0101: You're now a contributor (can file tickets on the bug tracker, comment on tickets, and comment on wiki pages) plus EditWiki permissions03:02
azonenbergif i see good work you may get full commit access in the future03:03
azonenbergAnybody else?03:03
azonenbergB0101: The FreeEDATools wiki page is just a start, if you're looking for something to work on feel free to add some more content there03:03
B0101ok03:05
azonenbergAs with all of the other wiki pages, of course, but that's one that i specifically know needs work03:05
azonenbergGoing to grab a bite, then off to the lab for some testing of liftoff patterning using a slightly thicker hardmask than yesterday03:10
berndji just checked, magic's native file format looks pretty merge-friendly03:19
azonenbergberndj: Interesting, I might have to take a look at that03:19
berndjits UI does however look like something that escaped from 198003:19
azonenbergI'm not really tied down to Glade very much, i only have a few test patterns and i can always dump them into a GDS and pull them into another tool03:19
berndjbut i found i got used to it fairly quickly03:19
azonenbergWant me to set you up on the googlecode project too? You can add such info to the wiki03:20
berndji don't think i'll be much of a contributor, but do as you like ;)03:20
azonenbergwell if you're interested pm me your googlecode email03:21
CIA-67homecmos r81 | wiki/FreeEDATools.wiki | Edited wiki page FreeEDATools through web user interface.03:55
CIA-67homecmos r82 | wiki/FreeEDATools.wiki | Edited wiki page FreeEDATools through web user interface.03:55
B0101Oh, CIA logs any changes to the wiki...03:58
azonenberg_labTime to have some fun...04:12
azonenberg_labB0101: There seems to be a little formatting glitch on the EDA tools page - i think you need a blank line after the heading marker for it to format right04:15
azonenberg_labOther than that, good start04:15
B0101ok noted04:16
azonenberg_labW00t05:45
azonenberg_labThis one looks pretty good05:45
azonenberg_labGonna try baking it and KOH'ing05:45
azonenberg_labSome residue in areas that should have been lifted off but the hardmask looks undamaged where it should be05:45
azonenberg_labpics coming shortly05:46
Action: azonenberg_lab opens 4-inch cassette labeled "Furnace carrier wafer" (aka "cookie sheet")05:46
CIA-67homecmos r83 | trunk/lithography-tests/labnotes/azonenberg_labnotes.txt | Updating lab notes for today's experiments.05:48
azonenberg_labPics uploading in a few05:48
azonenbergUploading...05:51
azonenberghttp://colossus.cs.rpi.edu/~azonenberg/images/homecmos/2011-06-19/S7300889.JPG06:00
azonenbergOther files in the dir are other shots from the same session but this one is a nice overview of the successful die at 100x06:01
Action: azonenberg waits another 45 mins for wafer to bake06:16
azonenberg_labDie is in KOH now, here's hoping it works...07:19
CIA-67homecmos r84 | trunk/lithography-tests/labnotes/azonenberg_labnotes.txt | Updating lab notes07:24
azonenberg_lab:( didnt work07:24
azonenberg_labhardmask broke off during the etch07:24
azonenbergSome pattern was visible though07:29
azonenbergSo i'm not sure what happened07:29
azonenbergSuspecting thermal shock during baking07:29
B0101hi11:48
CIA-67homecmos r85 | wiki/FreeEDATools.wiki | Edited wiki page FreeEDATools through web user interface.11:49
B0101Azonenberg: Fixed the problem11:50
B0101I am going to find and add more links...11:51
CIA-67homecmos r86 | wiki/FreeEDATools.wiki | Edited wiki page FreeEDATools through web user interface.11:54
CIA-67homecmos r87 | wiki/FreeEDATools.wiki | Edited wiki page FreeEDATools through web user interface.12:29
CIA-67homecmos r88 | wiki/FreeEDATools.wiki |12:48
CIA-67Edited wiki page Free EDA Tools through web user interface.12:48
CIA-67Edited most of the links and edited summary12:48
B0101Hi21:33
B0101Azonenberg: Did your etch succeed?21:33
azonenbergB0101: Not as well as I'd like21:33
azonenbergThe hardmask cracked during baking and broke off21:33
azonenbergBut i'm very close21:34
azonenbergi think i just need to do slower heat/cool cycles and use a slightly thinner hardmask21:34
azonenbergif it's too thick it cracks more readily21:34
azonenbergI noticed the first coat was too thin so i did a second21:34
azonenbergbut the second i spun too slowly and it got way thicker than i had intended21:34
azonenbergi overcompensated21:34
B0101oh, by the way, i did editing to the Free EDA tools wiki21:35
B0101I have got all the links21:35
B0101You could take a look to see if my edits were OK.21:37
azonenbergI glanced through them an hour or so ago, they look fine21:38
azonenbergKinda busy atm, will hopefully be free later today21:39
B0101ok21:39
bart416azonenberg, did you already modify an oven so you can control it with a computer?22:16
azonenbergbart416: no22:16
azonenbergI have a lab oven with a decently accurate thermostat but no custom profile capabilities22:16
azonenbergThe furnace i am looking at, iirc, has a programmable controller22:16
bart416Ah22:17
bart416My contraption for reflow is working pretty well I think22:17
bart416the temperature control is getting along22:17
bart416But it causes pretty big spikes using PWM, so need to figure out a way to fix that22:18
azonenbergi see22:19
azonenbergI do have a toaster oven that i was planning to turn into a reflow rig22:19
azonenbergJust havent done it yet22:19
Action: azonenberg wonders how hard it might be to buy some solder balls and make his own FCBGA22:19
azonenbergrather than using wire bonding22:19
azonenbergif the pad pitch is nice and large it might not be to bad22:20
azonenbergtoo*22:20
bart416Did you see those methods to put ICs in flexible flat cables?22:20
bart416Or flexible prints?22:20
bart416They basically seem to just put them in circuit and solder the traces directly onto it22:21
azonenbergYou're talking COF (chip on flex)?22:23
azonenbergI havent studied it in too much depth22:24
bart416Dunno, I've seen a couple of methods when studying methods for reflow soldering22:24
azonenbergI just mean COF in particular22:24
azonenbergSo tonight I'll be running a test using my comb drive mask from the mems-tests directory22:25
bart416Don't know if it's that particular method, but the advantages were rather interesting22:25
bart416:D22:25
bart416How thick is your hardmask now?22:25
azonenbergIt'll be on <100> and therefore will not be etchable deep enough to work22:25
azonenbergBut i have more of that and its cheaper22:26
azonenbergSo i'll test on that and when i get good yields switch to the <110>22:26
azonenbergAnd actually, thickness is TBD lol22:26
azonenbergWhen i spin coat on a blank wafer it's 225nm ish22:26
azonenbergBut with liftoff its harder to really tell22:26
azonenbergThe thickness i had in that last image was huge *looks up chart to estimate*22:26
bart416Somebody showed something interesting in ##electronics yesterday22:27
bart416A DIY electron microscope22:27
azonenbergSEM or TEM?22:27
azonenbergOr AFM?22:27
bart416SEM22:27
azonenbergI think i saw that one, was the guy imaging a big nut or something?22:27
azonenbergSomething large and not getting nearly enough magnification to be useful yet22:27
bart416Yeah, it's the same guy, but he later on went to do a grid22:28
bart416And was already going into the micrometer range22:28
azonenbergInteresting22:28
bart416He said he's going to publish his documentation on it on the internet22:28
azonenbergNice22:28
bart416So maybe with some luck some nut comes along and makes something you can actually use22:28
azonenbergLol, perhaps22:29
berndjbtw, what's a good keyword to add when searching for people who do stuff only Big Industry (tm) is supposed to be doing?22:29
berndjcalling it "homemade" can seem inaccurate22:29
azonenbergYeah, i have no idea22:29
azonenbergMakes it hard to find others22:29
bart416DIY22:29
azonenbergThats what i used22:30
berndjsometimes i have luck just googling the jargon22:30
azonenbergBtw - by counting intereference fringes it looks like the hardmask in my last test was something over 800nm thick22:30
azonenbergWhich explains the cracking22:30
azonenbergthats like 4x thicker than it should be22:30
bart416wow, 800 nm is really thick22:31
azonenbergI did a double coat AND dropped the RPMs22:31
azonenbergone or the other is fine, but both is too much22:31
azonenbergOne layer at max rpm without photoresist in the way gives, as i mentioned, somewhere around 225nm22:31
bart416You could probably calculate the thickness of the layers if you bothered with it22:31
azonenbergAgain all of these values are estimates22:31
azonenbergI dont know the refractive index is the thing22:31
azonenbergsince its spin coated the nubmers are different than for bulk22:31
azonenbergits not as dense22:31
azonenbergI'm estimating it to be comparable to SiO2, but it isnt22:32
azonenbergi could be off by 30% either way22:32
azonenbergBut it's still way thicker than it should be, that much is certain22:32
berndj800nm already accounting for Ta2O5's highish index of refraction?22:32
azonenbergberndj: 800nm assuming SiO222:32
azonenbergOtherwise, it might be more22:32
berndjerr, less?  as in, you need less Ta2O5 to give the same optical path length?22:33
azonenbergOh, good point22:33
azonenbergSorry about that22:33
azonenbergFor SiO2 it would be either 890 or 1510 in the thickest part22:34
azonenbergI couldnt tell if one spot on the edge was one fringe or two22:34
azonenbergAnd given how high the index is, my previous estimate of 50nm might actually be overkill for what i had in my old tests22:34
azonenbergit might be more like 3022:34
berndjdo you count under white light?22:34
azonenbergberndj: Yes22:34
azonenbergHalogen microscope lamp22:34
berndji guess your chart is made for broadband light, but in general, fringes show up much more under narrowband light.  CFLs work quite well22:36
azonenbergYeah22:36
azonenbergIf you want to try giving a better estimate than me, feel free http://colossus.cs.rpi.edu/~azonenberg/images/homecmos/2011-06-19/S7300900.JPG22:36
azonenbergThis is actually Ta2Cl1022:36
azonenbergbefore baking22:36
bart416I wouldn't worry about it too much, just make sure it's not too thick so it doesn't crack again22:36
azonenbergYeah, thats why i didnt recalculate either22:37
azonenbergIt didnt seem worth the effort22:37
azonenbergThoguh getting a ta2o5 color chart would be nice if anyone wants to run the math22:37
bart416First get it working, then fine tune it22:37
azonenbergAnd yeah22:37
azonenbergTonight i'll be doing some more tests and we'll see what happens...22:37
azonenbergI feel like we're getting close22:44
azonenbergOnce I get lithography of silicon working pretty reliably it opens up a ton of possibilities22:44
azonenbergThe next big unsolved problem is metal deposition22:45
azonenbergPatterning of metal can be done with an HCl : H2O2 : H2O etch which is CMOS compatible and won't diffuse through my photoresist22:45
azonenbergI've used it on copper in the past with good results22:45
azonenbergAnd it wont be nearly as difficult as patterning of, say, SiO2 or Si22:45
azonenbergMetal deposition can be done by evaporation or sputtering, pretty much22:46
azonenbergBoth require vacuum22:46
B0101hi, back from Breakfast, what have I missed?22:46
azonenbergBut sputtering needs a much less deep vacuum since you're actually letting inert gas into the chamber22:46
azonenbergsomething like 7E-1 torr vs 1E-6 for evaporation22:47
azonenbergSputtering has its own set of problems, though22:47
azonenbergEven if you ignore the need for inert gas supply22:48
azonenbergSince you arent pumping down really deep, there may be traces of oxygen22:48
azonenbergand nitrogen22:48
azonenbergMeaning that you may get oxide/nitride contamination if you are sputtering anything reactive22:48
azonenbergvs gold or platinum or another noble metal22:48
azonenbergNoble metals, however, are very tough to pattern22:48
azonenbergby anything but liftoff22:48
azonenbergAnd liftoff of a sputtered film is difficult because the coating is pretty conformal22:49
azonenbergBut if we can figure out how to sputter something like aluminum or copper we're in decent shape22:49
bart41610^-6 is in the range of a normal vacuum pump22:49
azonenbergExcept copper has its own set of problems when used with CMOS22:49
azonenbergbart416: Um, i dont think so22:49
bart416well, with normal I mean non expensive azonenberg :|22:50
azonenbergThe lowest i've ever hit with a mechanical pump was 1.2E-1 torr22:50
berndjin the old days people made mirrors with some weird amalgam process22:50
azonenberg2 stage rotary vane22:50
berndjno vacuum needed!22:50
azonenbergA diffusion or turbopump or similar is pretty much necessary to go much deeper22:50
azonenbergThe best mechanical pump i've ever seen was advertised as hitting 4E-2 torr which is still high for evaporation22:51
azonenbergBut realistic for sputtering22:51
bart416mechanical is normal for you? |22:51
bart416The most normal for me is using a water stream to cause negative pressure differential22:51
azonenbergbart416: Normal meaning 2-stage rotary vane like http://unitednuclear.com/index.php?main_page=product_info&cPath=28_52&products_id=40522:51
azonenbergbart416: Those things cant go below the vapor pressure of water22:52
azonenbergI've used them once22:52
bart416azonenberg, you're confusing my definitions of normal with yours22:52
berndjput a piece of sodium inside as a getter22:52
azonenbergDiffusion pumps are very similar but use oil or something with a lower vapor pressure22:52
bart416Normal in what sense?22:52
bart416first with normal I meant non expensive22:52
bart416But you define normal as mechanical and other simple designs22:52
azonenbergAnd $300 isnt that bad for a vacuum pump22:52
azonenbergTurbos cost >$5K22:53
bart416Mechanical not being normal for me as there are so much sub divisions in it :|22:53
azonenbergA diffusion pump, though, can probably be done pretty cheap22:53
berndjthe diy laser guys sometimes make their own diffusion pumps, iirc22:53
azonenbergberndj: Interesting22:53
berndjor cryotraps22:53
bart416You can probably get one fairly cheaply from an old lab equipment sale22:53
azonenbergI've never tried doing a cryopump22:54
azonenbergBut i imagine it's doable22:54
berndji imagine you can get hold of some liquid N2 fairly cheaply22:54
bart416http://www.belljar.net/forum/dp001.pdf22:54
bart416Looks achievable enough if you have access to a lathe22:55
lekernelis that a diffusion pump?22:55
bart416Yes22:55
azonenbergI do, my school machine shop has several manuals and one CNC22:55
berndjazonenberg, that H-shape fringe thing i'm looking at, is the fringey bit the Ta2Cl layer?22:55
azonenbergberndj: The background is silicon22:56
azonenbergThe fringes are Ta2Cl1022:56
berndjah.  those edges make it real difficult to count :(22:56
lekernelazonenberg: cryopumps are super simple, they're just a bottle of zeoliths frozen with liquid nitrogen22:56
azonenbergthe active ingredient in Tantalumfilm (solvent is denatured alcohol which has already evaporated)22:56
azonenbergWhich hydrolyzes to Ta2O5 after baking22:56
azonenberglekernel: I know22:56
azonenbergIt just means keeping cryogenics around22:56
azonenbergone more thing to add to the supplies list22:56
azonenbergA diffusion pump might be doable though22:56
bart416Liquid nitrogen doesn't come cheap...22:57
lekernelthere is an article explaining how to DIY them in Amateur Scientist22:57
lekernelliquid nitrogen is 10 cents a liter unless you get ripped off22:57
bart416You get it at 10 cents a liter?22:57
bart416Wow o_O22:57
berndjyup22:57
bart416Where the hell do you buy it?22:57
berndjbig industrial users of oxygen have tanks of liquid oxygen22:58
berndjat the gas yard :)22:58
bart416Only place where I can get it here is a small lab about 5km down the road22:58
berndjif you have an interesting story (and you do) you could twist someone's arm to let you "find" some while they aren't looking22:58
azonenberglol22:59
berndjyou don't really care about purity though; just the low temp22:59
bart416lol22:59
azonenbergTrue, since i'm not exposing it to the chamber directly22:59
azonenbergJust through conduction22:59
berndjdon't lol, that's how a model rocketry guy i know got his oxidizer!23:00
azonenbergo_O23:00
bart416berndj, mind you these are the same guys that were willing to sell me nitroglycerine...23:00
berndjnow you made me lol23:00
bart416Not much but still o_O23:01
bart416You know where you might find some info on building a good vacuum pump23:01
bart416All those fusor project websites23:02
bart416You need a pretty good vacuum pump for that23:02
azonenbergYeah, good point23:02
berndjhmm, i vaguely recall there being a yahoo group specifically for vacuum stuff23:02
azonenbergI was going to save that until I had lithography working, but if anyone wants to do the research and post info to the wiki that'd be great23:02
azonenbergEvaporation is a lot easier to do than sputtering and also has better liftoff profiles23:02
azonenbergAnd i'd prefer it, but i need a way of getting deep vacuum23:03
berndjdoes silver count as "noble"?23:03
azonenbergberndj: I dont think so23:03
azonenberggold, platinum, ruthenium23:03
azonenbergpalladium23:03
berndjas in, can you etch silver23:03
azonenbergI believe so23:03
azonenbergJust not sure with what23:03
bart416btw, this is one of the results for DIY vacuum pump: http://tubedevices.com/alek/pwl/lc1d/homemade_nixie_tubes.pdf23:03
berndjif you want to / have to avoid vacuum (for now), could that silvering process + electroplating help?23:03
azonenbergberndj: No, i have other deposition needs that cant be done without vacuum23:04
azonenbergFor example, polysilicon23:04
berndjah, ok23:04
azonenbergI have five silicon crystals suitable for evaporation (5mm cubes) sitting around waiting for a suitable chamber, pump, etc lo23:04
bart416wtf, somebody is building a linac in his garage o_O23:05
berndji thought for polysilicon you run some silane (SiH4) CVD type process?23:05
berndjyup bart41623:05
azonenbergberndj: CVD is the most common method23:05
azonenbergBut you can evaporate or sputter too23:05
bart416That sure as hell beats the fusor guys23:05
azonenbergIts just less popular for mass production23:05
bart416But you aren't doing mass production...23:06
azonenbergExactly23:07
azonenbergHence sputtering or evaporation are preferred23:07
azonenbergi want to avoid keeping SiH4 around at all cost :p23:07
azonenbergA small amount of argon for sputtering, if i cant avoid it, ok23:07
bart416Yeah, but argon isn't that expensive all things considered23:08
bart416Unless if you want enough for the rest of your life23:08
azonenbergI'm more concerned about the safety implications of keeping giant cylinders of potentially toxic gases in the living room :P23:08
azonenbergA small 20 ft^3 lecture bottle of argon i can handle23:08
bart416Argon isn't toxic :P23:08
azonenbergbut SiH4 is both flammable and toxic and i dont want it around23:08
bart416heh23:09
azonenbergArgon is inert and pretty harmless23:09
bart416Maybe you can use helium, that'd be even cheaper23:09
azonenbergEspecially if the cylinder is small enough that hypoxia from a leak isnt a serious concern23:09
azonenbergbart416: for sputtering you need a reasonably heavy gas23:09
azonenbergneon or argon work best23:09
berndjsomething's wrong in http://en.wikipedia.org/wiki/Silicon - check boiling point vs vapour pressure table.  boiling point listed as 2628K, but 100kPa vapour pressure at 3537K???23:09
B0101Bye guys, off to work!23:10
bart416berndj, go and get a good periodic table, don't use wikipedia!23:10
berndji think even a big cylinder of argon won't displace enough of the air in your room to cause a problem23:10
berndjmaybe the tiniest of bathrooms23:11
bart416the only way I see it cause a problem if it releases its entire contents at once23:11
azonenbergberndj: 20 ft^3 isnt a concern23:11
azonenbergI just would be cautious about one of the several-hundred-ft^3 ones23:11
bart416But then it's probably going to create some extra ventilation holes to compensate for that23:11
azonenbergLeaks of those (especially N2) have been known to make a decent sized room hypoxic23:11
azonenbergthe trouble with inert gases is that you dont realize you're out of air until you keel over23:12
azonenbergvs CO2 you notice immediately23:12
berndjbart416: door-sized ventilation holes?23:12
bart416berndj, I'd say that depends on the material the wall's made from :')23:12
azonenbergBut in a nice large room (20-30 feet across) 20 ft^3 would be harmless even if released all at once23:12
bart416In a nice large room worst case scenario you'd get a little bit light headed23:13
berndj20ft room would be maybe 3200ft^3... displacing even several hundred ft^3 shouldn't kill you23:14
bart416Damnit stop working in non SI units, it's confusing o_O23:14
berndjair is 20% O2, you'd need to halve that to kill.  funny, was just reading about fire suppression23:14
bart416<3 Halon :P23:15
bart416It's a shame they banned it23:15
bart416Best fire extinguishers ever :S23:15
bart416Those regular ones in cars are crap23:16
bart416You can't even put out a small camp fire with those23:16
bart416Anyway 'nite23:17
--- Mon Jun 20 201100:00

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