soul-d | k done reading for today :) i conculde that e-readers at least this (sony prs-t1) is close to what these devices should do few quirks in software (and ofcourse some type of sony usb cable thingy) but reading is alot better then from lcd | 00:02 |
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azonenberg | So... I've already demonstrated the ~100um resolution i'm looking for on PCBs so it should be no problem to get it on silicon for dicing | 00:29 |
azonenberg | Time to print some masks | 00:30 |
CIA-67 | homecmos r148 | trunk/lithography-tests/labnotes/azonenberg_labnotes.txt | Today's lab notes | 02:28 |
azonenberg | http://imgur.com/a/xNH1x | 02:30 |
azonenberg | Slow progress with classes and everything | 02:45 |
azonenberg | But work is progressing | 02:45 |
Helldesk | how do you make the masks? | 04:13 |
azonenberg | Helldesk: Laser printer and transparency film from staples | 04:14 |
azonenberg | These are contact masks, 1:1 scale | 04:14 |
azonenberg | so i'm limited to 600dpi | 04:14 |
azonenberg | projection masks get much higher resolution since i reduce optically | 04:15 |
azonenberg | but the cost is that i can no longer do a whole wafer in one exposure | 04:15 |
azonenberg | almost done with a cross section rendernig of the comb drive process | 04:25 |
azonenberg | ok, model is taking longer to design than anticipated | 06:25 |
bart416 | auch azonenberg | 07:30 |
azonenberg | Hai | 07:31 |
soul-d | morning | 07:31 |
azonenberg | Process outline coming in a few mins | 07:32 |
azonenberg | putting the final touches on it now | 07:32 |
Action: azonenberg crops a few dozen screenshots | 08:01 | |
azonenberg | http://imgur.com/a/kxARq | 08:12 |
azonenberg | lekernel: http://imgur.com/a/kxARq | 08:20 |
soul-d | :) | 08:22 |
azonenberg | Any thoughts on the process? | 08:24 |
azonenberg | Wafer is at step 2 right now | 08:24 |
soul-d | well it made it more clear for me | 08:24 |
azonenberg | 3-5 are scheduled for tuesday | 08:24 |
azonenberg | when i can get time on the evaporator | 08:24 |
azonenberg | After the 400um KOH etch, the dies are separate | 08:25 |
soul-d | you use university tools ? | 08:25 |
azonenberg | and all future lithography is done on the projection rig one at a time | 08:25 |
azonenberg | The evaporator is the one thing i dont have at home yet | 08:25 |
bart416 | You should have written the description of the process in VHDL... | 08:25 |
azonenberg | As well as the SEM i use for when my optical scope isnt good enough | 08:25 |
azonenberg | soul-d: and thats exactly what it was intended to be for | 08:26 |
azonenberg | To make the process more understandable | 08:26 |
azonenberg | i'm going to try and make a little presentation (poster or slideshow TBD) when i get further on in the process | 08:26 |
soul-d | ok so those things are just for the moment not that they are imposible to do at home ? | 08:26 |
bart416 | Wren't you looking into sputtering? | 08:27 |
azonenberg | Including in-process SEM images | 08:27 |
azonenberg | and optical | 08:27 |
azonenberg | bart416: I am exploring both sputtering and evaporation | 08:27 |
azonenberg | Both are within the realm of possibility for a dedicated hobbyist | 08:27 |
bart416 | soul-d, building a high enough resolution SEM at home is tricky at the best of times | 08:27 |
azonenberg | The SEM is not strictly necessary | 08:27 |
bart416 | It's a design project on its own | 08:27 |
azonenberg | i could do everything i did with an optical scope | 08:27 |
bart416 | It'd take well over a year to get something that'll perform good enough | 08:27 |
azonenberg | but the sem is there and it helps me sanity-check things | 08:27 |
bart416 | And then you need to develop all the specialised equipment to surround it and the right detectors | 08:28 |
azonenberg | bart416: everhart-thornley detector shouldnt be too tough to build | 08:28 |
azonenberg | control would be all DSP | 08:28 |
azonenberg | make no doubt about it, i intend to build one some day | 08:28 |
azonenberg | But its a lower priority | 08:28 |
azonenberg | soul-d: Evaporation is pretty simple conceptually | 08:29 |
bart416 | With an everhart-thornley detector you're not going to get very good results though | 08:29 |
soul-d | currently reading books more on fpga though found one that also treats the lower level a bit more | 08:29 |
azonenberg | bart416: but it'd be good for starters | 08:29 |
bart416 | And you won't get many of the other advantages of a SEM | 08:29 |
azonenberg | soul-d: Stick a tungsten filament between two electrodes | 08:29 |
azonenberg | coil copper wire around it | 08:29 |
azonenberg | stick your sample underneath | 08:29 |
azonenberg | put a bell jar on top, suck out the air | 08:29 |
soul-d | just wondering how truly homecmos it would be | 08:29 |
azonenberg | run current through filament, it heats up | 08:29 |
azonenberg | metal evaporates | 08:29 |
azonenberg | soul-d: The evaporation is the one process i dont do at home | 08:30 |
soul-d | yeah i think i read on it for making mirros for | 08:30 |
soul-d | telescopes | 08:30 |
azonenberg | and as soon as i can afford a vacuum pump, i'll do it | 08:30 |
azonenberg | Exactly | 08:30 |
azonenberg | same process | 08:30 |
soul-d | you just have sticky and no sticky layers on wafer ? | 08:30 |
azonenberg | sticky? | 08:30 |
azonenberg | what do you mean sticky | 08:30 |
soul-d | egg plases you want depost | 08:30 |
azonenberg | oh | 08:30 |
soul-d | and stuff you protect | 08:30 |
azonenberg | Evaporated films will stick to anything in a straight line from the source | 08:31 |
azonenberg | so you can cast shadows in the film with photoresist etc | 08:31 |
azonenberg | You can also put resist over the film and etch through holes in the resist | 08:31 |
azonenberg | i use both techniques in this process | 08:31 |
azonenberg | Generally speaking, all microfab processes are in one of two broad classes | 08:33 |
azonenberg | additive and subtractive | 08:33 |
soul-d | k yeah makes more sense now then yesterday ;) | 08:33 |
azonenberg | Evaporation is an additive process, so is spin coating | 08:33 |
azonenberg | etching is subtractive | 08:34 |
azonenberg | In this case i am patterning the bottom Cr by both | 08:34 |
azonenberg | i deposit everywhere that i want it from time zero | 08:34 |
azonenberg | etch the silicon a bit | 08:34 |
azonenberg | then remove part of the remaining Cr | 08:34 |
soul-d | yeah intresting stuff how did you start i mean doubt you jumped to these sizes or technology | 08:47 |
bart416 | azonenberg, I think soul-d doesn't know about trial and error :P | 09:44 |
azonenberg | bart416: actually? | 18:20 |
azonenberg | 20um was my first attempt at going smaller than the 150-200um design rule i had before | 18:20 |
azonenberg | that was contact lithography on printed circuit board | 18:21 |
azonenberg | i just threw a 10x objective in between | 18:21 |
bart416 | Sounds like trial and error to me :P | 18:22 |
azonenberg | bart416: Lol | 18:23 |
azonenberg | It pretty much was | 18:23 |
azonenberg | Just saying, i didnt slowly and painfully work my way down from 200 | 18:24 |
azonenberg | However, 20 has been a bit of a brick wall in that i'm having trouble shrinking using techniques i've tried so far | 18:24 |
azonenberg | i hit 5 a few times but cant do it reliably | 18:24 |
bart416 | Have you tried changing light source to something more uniform? | 18:43 |
azonenberg | Yes | 18:43 |
bart416 | What wavelength is ideal? | 18:44 |
azonenberg | Depends on the resist | 18:44 |
azonenberg | Mine is 405nm peak sensitivity | 18:44 |
bart416 | 405nm, lets see if I have any lasers for that | 18:44 |
azonenberg | I'm now using a fiber optic illuminator (wideband halogen source) | 18:44 |
azonenberg | Problem is, the beam is a little small | 18:45 |
azonenberg | i need to build a condenser to widen the beam | 18:45 |
azonenberg | Anything from 365-405 will work | 18:45 |
azonenberg | maybe even up to 450ish | 18:45 |
bart416 | how wide do you need? | 18:46 |
azonenberg | that's mercury vapor G through I line | 18:46 |
azonenberg | About 2cm | 18:46 |
azonenberg | thats the diameter of the camera port on top of the scope that i put the mask | 18:46 |
azonenberg | i need a relatively collimated beam of that diameter | 18:46 |
bart416 | 2cm, that'll be hard | 18:47 |
azonenberg | and as uniform as possible | 18:47 |
azonenberg | top-hat distribution ideally | 18:47 |
bart416 | Well, the issue is you'd be widening the beam a lot | 18:48 |
bart416 | It'd lose its intensity advantage | 18:48 |
azonenberg | I can handle a slightly longer exposure, right now i have about a ~1cm disk at the end of my fiber bundle | 18:48 |
bart416 | Only UV laser I have is in my own photoresist setup | 18:50 |
Action: azonenberg doesnt have any lasers | 18:51 | |
azonenberg | except for ~760nm 1-5 mW diodes | 18:51 |
azonenberg | but those dont really count for lithography | 18:51 |
bart416 | Also, blu ray laser | 18:52 |
bart416 | Its perfect | 18:52 |
bart416 | It's exact 405nm | 18:52 |
azonenberg | Yeah, i agree | 18:52 |
azonenberg | But if i was using one it'd be for direct write | 18:53 |
azonenberg | in a much narrow beam | 18:53 |
bart416 | http://www.dealextreme.com/p/100mw-405nm-blue-violet-royal-purple-laser-module-3v-80923 looks nice | 18:53 |
azonenberg | probably with nanosecond-level pulses | 18:53 |
azonenberg | microsecnd* | 18:53 |
bart416 | I tried pulsed lasers before | 18:54 |
bart416 | I found them unsuitable for PCB exposure | 18:55 |
azonenberg | You misunderstand | 18:55 |
azonenberg | i'd do short pulses on the bluray diode for direct write | 18:55 |
bart416 | I doubt they'll do better at smale scale | 18:55 |
azonenberg | because each pixel is so small i dont need a lot of energy | 18:55 |
azonenberg | basically, figure out how much energy each pixel needs to get exposed completely | 18:55 |
azonenberg | and differentiate | 18:55 |
bart416 | Well, the issue I found is actually the shape of the beam | 18:56 |
azonenberg | how so? | 18:56 |
bart416 | Round beam, square pixels | 18:56 |
azonenberg | I'd want a ~5um round beam | 18:56 |
azonenberg | 20um square pixels with rounded corners | 18:56 |
bart416 | You'd need significant overlap I think | 18:57 |
azonenberg | Yeah | 18:57 |
azonenberg | so for a 20um line i do 5um shots centered at 0, 2.5, 5, 7.5, 10, 12.5, 15, 17.5, 20 | 18:57 |
azonenberg | assumption is that the desired tophat beam will actually be a little more gaussian | 18:58 |
berndj | is a laser diode's light sufficiently collimated for lithography? | 19:19 |
berndj | i thought that mattered | 19:20 |
azonenberg | berndj: You'd need optics | 19:21 |
azonenberg | But you need optics even more with a halogen lamp :p | 19:21 |
berndj | optics can't collimate a beam without losing some of the light | 19:21 |
berndj | (imprecise jargon) | 19:22 |
azonenberg | berndj: yes, i know | 19:22 |
azonenberg | Thats why you get a nice high power source | 19:22 |
azonenberg | so you can afford to lose some | 19:22 |
berndj | ah ok | 19:22 |
berndj | is a bluray LD a "nice high power source"? | 19:22 |
azonenberg | 200 mJ/cm^2 is what i need | 19:22 |
azonenberg | my die is maybe 1/4 cm^2 (5mm square) at most | 19:22 |
azonenberg | os i need 50 mJ over the entire die | 19:22 |
azonenberg | Delivered over several minutes by a moving laser head | 19:23 |
azonenberg | one milliwatt of actual energy after optics is probably enough | 19:23 |
azonenberg | bluray diode is a few hundred i think | 19:23 |
azonenberg | i'll probably have to pulse it to get average intensity down low enough to not overexpose | 19:23 |
CIA-67 | homecmos r149 | trunk/papers/ (17 files in 3 dirs) | Added first draft of project poster | 19:31 |
soul-d | don't you need to move the laser realy precise with that method | 19:50 |
azonenberg | soul-d: yes, or reflect it off precisely aimed mirrors | 19:50 |
azonenberg | But it would let me get better resolution than i can with a normal printer | 19:50 |
azonenberg | thats the whole point | 19:50 |
soul-d | how did you start btw on what size since you mention printer ? you should make entry howto or proof of concepts ... maybe browse site | 19:57 |
azonenberg | soul-d: I'm actually doing a poster providing a summary of what's going on now | 19:58 |
soul-d | din't even knew you had nyano technology :) | 19:58 |
azonenberg | hoping to present at the CDMMS (capital district microscopy and microanalysis socity) meeting next month | 19:58 |
azonenberg | they have their anual microanalysis and materials science poster competition | 19:58 |
soul-d | oh yeah was looking at microscope alwasy wanted one but i usaly start looking and by time im done i need 10K + | 19:59 |
azonenberg | even in the (very likely) event i do not win best poster, it should help increase awareness of the project | 19:59 |
azonenberg | and mine was $1.2k including the camera | 19:59 |
azonenberg | lol | 19:59 |
soul-d | yeah found a site with ocassions | 19:59 |
soul-d | but still pricy | 19:59 |
azonenberg | amscope.com is where i got this one | 19:59 |
azonenberg | Not the greatest scope, i am definitely seeing limitations | 19:59 |
soul-d | netherlands here so stuck to looking local | 20:00 |
azonenberg | But i could also afford it | 20:00 |
azonenberg | Ah, i see | 20:00 |
soul-d | im verry intrested thats why i asked is this where digital meets chemistry :) | 20:01 |
soul-d | and other fun stuff | 20:01 |
azonenberg | Yep | 20:02 |
soul-d | you have a list of intresting books ? currently reading bit out of "digital systems design with fpga" wich starts a bit talking on the technology's behind it but still different avenue | 20:04 |
azonenberg | I've been doing most of my learning online actually | 20:05 |
soul-d | k yeah din't fix wifi yet here so cant use ereader online :P thats why documents still preferred | 20:08 |
soul-d | realy like the e-ink stuff | 20:08 |
soul-d | interesting at least would be to figure out if one in eu / netherlands has acces to chemicals needed | 20:24 |
soul-d | cause if you are i assume usa based ? | 20:24 |
azonenberg | Yes, i am | 20:25 |
azonenberg | But most of the materials i've been using are not hard to get hold of | 20:25 |
azonenberg | HCl, NaOH | 20:25 |
azonenberg | Distilled water, acetone | 20:25 |
azonenberg | the trickiest one is photoresist | 20:25 |
azonenberg | oh, and hydrogen peroxide (3% aka drugstore grade) | 20:26 |
soul-d | got those is it the same as for pcb ? | 20:26 |
azonenberg | the resist? | 20:26 |
soul-d | yeah | 20:26 |
azonenberg | I am using liquid resist sold for PCBs | 20:26 |
azonenberg | I dilute it 50% with acetone to reduce the viscosity and thin the layer | 20:26 |
azonenberg | then spin coat | 20:26 |
soul-d | i think a shop in uk sold it to in a brush type thingy | 20:26 |
soul-d | or marker | 20:26 |
azonenberg | That wont work, you need to be able to do an even film | 20:27 |
azonenberg | Mine is sold as a liquid | 20:27 |
azonenberg | apparently its made in a spray can too, which is less good but if you spray it on and then spin coat you can probably get it nice and even | 20:27 |
soul-d | yeah i assumed it's a liquid inside ? and just tip to dispersi it evenly | 20:27 |
azonenberg | Yes | 20:28 |
CIA-67 | homecmos r150 | trunk/papers/003_Poster/Poster.odp | Continued work on poster | 21:27 |
azonenberg | http://colossus.cs.rpi.edu/~azonenberg/downloads/poster-pdf.pdf | 23:20 |
azonenberg | Anyone have comments? | 23:20 |
azonenberg | Presenting an updated version of this (need to finish the references and add pics from my experiments being conducted this coming week) next month | 23:21 |
soul-d | what is thecnical grade HCL egg % ? | 23:25 |
azonenberg | soul-d: Good point | 23:25 |
azonenberg | 32% | 23:25 |
azonenberg | added | 23:25 |
azonenberg | I need to shrink the text down by a bit, there's a little much | 23:26 |
azonenberg | and font should be larger | 23:26 |
azonenberg | For scale this will be printed on a 3x4 foot poster | 23:26 |
soul-d | yeah same for the KOH also % missing but i think you can get that at 99,9% ? | 23:27 |
azonenberg | The KOH is powder | 23:27 |
azonenberg | so almost pure | 23:27 |
soul-d | yeah draining cleaner stuff i think oposite of naoh | 23:27 |
azonenberg | there may be some impurities but its not like a dilute solution | 23:27 |
azonenberg | This was relatively high grade | 23:27 |
azonenberg | http://www.dudadiesel.com/search.php?query=%22potassium+hydroxide%22 | 23:28 |
soul-d | yeah got a labstore online you can order | 23:28 |
azonenberg | turns out this is actually food grade | 23:28 |
soul-d | also found a "garden" shop wich sells most chemicals | 23:28 |
soul-d | http://translate.google.com/translate?sl=nl&tl=en&js=n&prev=_t&hl=en&ie=UTF-8&layout=2&eotf=1&u=http%3A%2F%2Fwww.floratop.nl%2Findex.php%3Faction%3Dextra%26extra%3DA_overig_chemie%26lang%3DNL | 23:31 |
soul-d | would be first place for me to look for chems | 23:31 |
azonenberg | Lol | 23:31 |
azonenberg | Yeah, thats why mems is easier than cmos | 23:31 |
azonenberg | cmos is much more sensitive to trace metal impurities | 23:32 |
azonenberg | i am seriously skeptical as to how much i could do cmos wise without buying "real" trace metal grade supplies | 23:32 |
soul-d | ok so for cmos youd be bussy purifing resources or buying :P | 23:32 |
azonenberg | bipolar transistors might be a little less sensitive | 23:32 |
azonenberg | i have to read up more on BJTs | 23:32 |
soul-d | i like your spin coater makes it more home doable already :P understood more of the alliance programs i already had on system tried to install glade but need fresh linux install again | 23:34 |
soul-d | it worked but it also crashed a bit donno how realiable it is :) | 23:35 |
azonenberg | Yes, its not very reliable | 23:35 |
azonenberg | I use it because i havent had the time to learn any package that's more open and reliable | 23:35 |
azonenberg | But as long as i can export my design to GDS | 23:35 |
azonenberg | i can open it up in another tool | 23:35 |
soul-d | i think i had that mentor grapics progam somehwere around | 23:38 |
soul-d | but definetly not open | 23:38 |
azonenberg | lol | 23:38 |
azonenberg | yeah | 23:38 |
soul-d | i always download packages that are expensive just for fun :) | 23:38 |
soul-d | might come in ahndy some day :) | 23:38 |
azonenberg | lol | 23:39 |
soul-d | woulnd know where it is though :) | 23:40 |
soul-d | but you can't write it in vhdl ? | 23:40 |
soul-d | or hdl language ? | 23:41 |
azonenberg | You can do that for digital circuits but you still have to design the cell library | 23:41 |
azonenberg | and compile your design to cells + wiring | 23:41 |
soul-d | so comb drive is just cause of the pattern but what does it do ? | 23:57 |
azonenberg | soul-d: it's pretty much the mems equivalent of a solenoid | 23:58 |
azonenberg | was chosen as the first actual device to build because its relatively simple | 23:58 |
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