| B0101 | +q45 | 13:09 |
|---|---|---|
| glowplug` | Good afternoon all. | 17:07 |
| Sync_ | hello | 17:12 |
| Sync_ | glowplug`: thought about the direct litho for a bit | 17:17 |
| Sync_ | I still think an interferometer is the cheapest and best way to do the position measurement | 17:18 |
| Sync_ | the resolution/cost factor is very good | 17:18 |
| glowplug` | I'm working on the interferometer. Came to that conclusion as well. | 17:19 |
| glowplug` | Will be constructing a simple michealson and a bunch of micrometers to position the sample. What was your conclusion with the direct litho? | 17:20 |
| Sync_ | there are 100nm resolution glass scales, which would be cool | 17:20 |
| Sync_ | yeah a michelson is easy to do | 17:20 |
| glowplug` | It would be, but I can probably get 250nm accuracy with the cheap interferometer for pennies. | 17:20 |
| Sync_ | I should head to the scrapyard and see what machines they currently rip apart | 17:21 |
| glowplug` | What are your opinions with the direct litho vs mask | 17:21 |
| Sync_ | well | 17:22 |
| Sync_ | direct litho is probably fine for experimental work | 17:22 |
| glowplug` | At most universities from what I understand they use masks and spinning each layer with resist. | 17:22 |
| Sync_ | yup | 17:22 |
| Sync_ | it's cheaper if you have the equipment | 17:22 |
| glowplug` | I think that will be fairly easily to accomplish. | 17:22 |
| Sync_ | and for most experiments you only use a single mask set | 17:22 |
| Sync_ | hmm actually, reading the paper again, I almost have everything I'd need | 17:23 |
| Sync_ | I'd only have to get some mirrors for the interferometers | 17:23 |
| Sync_ | and somehow build an xy stage | 17:23 |
| glowplug` | If you give me a month I can send you an interferometer. | 17:24 |
| glowplug` | I know thats quite awhile. | 17:24 |
| glowplug` | Have a lot of personal crap going on right now thats keeping me from making progress. | 17:24 |
| glowplug` | Do you have micrometers? Spinny doohickie? (technical term). | 17:25 |
| Sync_ | well I have a few for measuring stuff | 17:25 |
| Sync_ | I have a few laser xy stages | 17:25 |
| glowplug` | We need a table with x y tilt and pan adjustments with micrometers. | 17:26 |
| glowplug` | I can build one.. but I need time. | 17:26 |
| Sync_ | I'd just need to order stuff from edmund or thorlabs | 17:26 |
| glowplug` | That will cost you a leg + arm. | 17:26 |
| Sync_ | well mirrors are cheap | 17:26 |
| glowplug` | I can build the table and the interferometer for ~$50 total. Depending on how much strugle I have putting together the tiny gearboxes. | 17:27 |
| glowplug` | I can use my CNC to cut 50/50 glass for 30 cents per 10mm square. Its a pain in the ass to cut glass but I can do it. | 17:27 |
| glowplug` | Add cute little acrylic stands and a dollor store diode you have the worlds cheapest interferometer. Haha | 17:28 |
| glowplug` | There are a few more things I haven't worked out | 17:29 |
| Sync_ | let me just look what thorlabs has for me | 17:30 |
| glowplug` | Alignment markers. Is a cheap 100x microscope and a point and shoot camera sufficient? | 17:30 |
| Sync_ | oh, that's an interesting problem | 17:31 |
| Sync_ | but yeah probably | 17:31 |
| glowplug` | The "actual" 100x microscopes that are ~$25 are probably unsuitable. | 17:31 |
| glowplug` | We need to find the actual optics. Seperately. | 17:32 |
| glowplug` | Then rig the point and shoot to the optics. This is pretty common stuff for telescope builder types. Do you know anyone that does that stuf? | 17:32 |
| Sync_ | well the actual optics sould be a microscope lens | 17:33 |
| glowplug` | Right. I've never purchased anything like that. | 17:33 |
| Sync_ | one could just make a setup that you put on the lens to aling | 17:33 |
| Sync_ | and then take off | 17:33 |
| glowplug` | But if I know its dimensions I should be able to get a ghetto mount for it that we could slap the point and shoot on. | 17:33 |
| glowplug` | Then we have a cute little screen to align our markers. | 17:34 |
| glowplug` | So the next. It's basically unaffordable to build a cartesian machine with 1um repeatable accuracy. It just wont happen. | 17:34 |
| Sync_ | hm, thorlabs has vis beamsplitter cubes at 135¬ | 17:34 |
| glowplug` | I can build a beamsplitter for 30 cents. | 17:35 |
| glowplug` | Thorlabs can jump off a cliff. Haha | 17:35 |
| Sync_ | or budget plates for 25 | 17:35 |
| Sync_ | well I'm used to order from them | 17:35 |
| glowplug` | Like I said if you can wait a month I can send you the stuff for free. | 17:35 |
| glowplug` | Also there are beamsplitters in cdrom drives which is a low cost option that doesnt require waiting for me to setup my CNC for glass. | 17:36 |
| glowplug` | You can probably find a pile of cdroms for free or <$5 | 17:36 |
| glowplug` | So the CNC thing. I'm not confident I can do it. So I've been trying to find an alternative. | 17:37 |
| soul-d | indeed telescope work bit diferent but you might get some intresting tools | 17:38 |
| glowplug` | I started thinking about laser projectors. Galvos aren't really suitable for exposing resist. They are super fast and not accurate enough. | 17:38 |
| soul-d | google for ATM in full Amature telescope making | 17:39 |
| soul-d | i assume theory behind the light stuff is same just have to do different calculations | 17:39 |
| glowplug` | For the galvos? | 17:40 |
| glowplug` | By the way did you just change names? Haha | 17:40 |
| Sync_ | yeah beamsplitters are not too bad commercially | 17:40 |
| soul-d | no just another someone :P | 17:41 |
| glowplug` | At any rate. Imagine a laser projector configuration. Two motors and two mirrors. The motors are microstepping servos with a 500/1 gearbox reduction. | 17:41 |
| glowplug` | Oh I see. Haha | 17:41 |
| glowplug` | So basically its the worlds worste laser projector that can draw a blue dot on a wall very very slowly and not make pictures at all. | 17:41 |
| glowplug` | But it can expose photoresist with 1 micron repeat accuracy. =) | 17:42 |
| glowplug` | I'm sorry. Microstepping steppers. | 17:42 |
| azonenberg | glowplug`: i considered that | 17:43 |
| azonenberg | I think cartesian mounting is a better option | 17:43 |
| azonenberg | even 10um accuracy is good enough | 17:43 |
| azonenberg | Bear in mind you only need 1cm or so of travel | 17:43 |
| azonenberg | don't even think about that kind of accuracy across a large field | 17:44 |
| Sync_ | it's not that hard over a large area | 17:44 |
| glowplug` | This thing might have a large field but it wouldn't be an extra cost if it did. | 17:44 |
| glowplug` | Cartesian adds all sorts of costs that the projector configuration avoids. | 17:44 |
| glowplug` | With no rotational to linear motion 90% of the cost is removed. | 17:44 |
| glowplug` | No ball screws, ball nuts, no linear encoder ect. | 17:45 |
| azonenberg | Maskless litho is great for making masks, but difficult to align to an existing pattern | 17:45 |
| azonenberg | I still think your best bet is to use direct write for making masks, then a contact aligner | 17:45 |
| glowplug` | That is the plan for sure. Masks make everything very easy. | 17:46 |
| azonenberg | With a contact aligner you just have a little track above the mask assembly | 17:46 |
| azonenberg | microscope slides in, tweak the micrometer knobs until the mask is lined up with the wafer | 17:46 |
| glowplug` | At any rate. Let me attempt the projector configuration with 10um as an accuracy target. If it works I will make and send out masks. If I fail then I waste a bunch of time. Haha | 17:46 |
| azonenberg | then slide it out and bring the UV lamp in | 17:46 |
| glowplug` | Except we are going to have an awesome color LCD for alignment because thats what badasses do. | 17:47 |
| Sync_ | hmm, the new blue lasers sure made stuff easier | 17:47 |
| Sync_ | no need to drag the ALC909 out | 17:47 |
| glowplug` | Yeah I'm just going to grab a blu-ray diode and call it. | 17:47 |
| glowplug` | I even get a free beamsplitter from the drive. | 17:47 |
| Sync_ | I like my tankless water heater with operation light | 17:48 |
| glowplug` | So does anyone have a plan for the spinny thingy? | 17:48 |
| Sync_ | yes | 17:48 |
| Sync_ | after I finish my exams I'll try to come up with something | 17:48 |
| glowplug` | Alright we are counting on you. No pressure. =P | 17:48 |
| Sync_ | other option is just to buy a spincoater | 17:49 |
| Sync_ | they are not too terribly expensive | 17:49 |
| glowplug` | Oh and if I fail with the projector configuration then I will be building a SCARA robot to try and replace it. If that fails then I don't know. Trust me it wont fail. =) | 17:49 |
| glowplug` | The way I determine if I DIY something is if the manufacturer of that thing doesn't have prices on their main page. | 17:50 |
| glowplug` | =P | 17:50 |
| glowplug` | I think spincoater meets that requirement. Haha | 17:51 |
| glowplug` | It looks like the "bio" people do spincoaters. | 17:51 |
| azonenberg | Building a spin coater isnt that har | 17:51 |
| azonenberg | hard* | 17:51 |
| azonenberg | i've homebrewed one already but it's too bulky | 17:51 |
| azonenberg | i'm going to try and shrink it using a BLDC from an RC airplane | 17:51 |
| azonenberg | will post plans once i finish | 17:52 |
| glowplug` | What RPM does the coater run at and what accuracy +/- do you need? | 17:52 |
| Sync_ | http://www.ebay.de/itm/251016709571 | 17:52 |
| azonenberg | What RPM, no clue | 17:52 |
| Sync_ | haha that's interesting | 17:52 |
| azonenberg | accuracy i've got, terrible | 17:52 |
| azonenberg | accuracy i'd like, better | 17:52 |
| azonenberg | My current coater is a flat plate on the end of an electric drill :p | 17:53 |
| glowplug` | Interesting. Thats more than I can spend though. Haha | 17:53 |
| Sync_ | well it's clearly not worth that | 17:53 |
| glowplug` | There is an open source BLDC controller now. That will give you the option to use an optical encoder and get extremely precise RPM control. | 17:53 |
| Sync_ | it's just a bldc | 17:53 |
| glowplug` | If you need ~1% then an ESC won't work. | 17:53 |
| Sync_ | there are enough opensource bldc controllers since a few years | 17:54 |
| azonenberg | Yeah | 17:54 |
| glowplug` | They are all piece of shit dead ends though. | 17:54 |
| glowplug` | The only one thats worth a damn, with decent code. Actually let me get the link onesec. | 17:54 |
| glowplug` | https://github.com/lgbeno/BLDC-Booster | 17:56 |
| glowplug` | You can get an MSP430 board for ~$5. Then you would have to add the sensored control but that wouldn't be too bad. | 17:57 |
| glowplug` | It honestly might be good enough without sensored. Certainly better than a chinese ESC. | 17:58 |
| Sync_ | that's nothing special | 17:59 |
| glowplug` | These guys have good MSP430 boards. https://www.olimex.com/Products/MSP430/Header/MSP430-HG2231/ | 17:59 |
| Sync_ | designs like that were around for some time | 17:59 |
| glowplug` | No it's not special other than the low cost of the MSP430. | 17:59 |
| glowplug` | And the code isn't.... a giant mess. | 17:59 |
| glowplug` | The interferometer is for aligning the sample correct? If we have a microscope/camera do we need it? | 18:00 |
| Sync_ | no the interferometer is for position feedback | 18:01 |
| glowplug` | During which stage? | 18:02 |
| Sync_ | you do not need if if you use a projector | 18:02 |
| glowplug` | Developing the mask? | 18:02 |
| Sync_ | but I'm not sure if that works | 18:02 |
| Sync_ | I'd try a scanner | 18:02 |
| azonenberg | http://homecmos.drawersteak.com/wiki/Main_Page | 18:02 |
| azonenberg | Who wants accounts? | 18:02 |
| glowplug` | It is a scanner. Sort of. It slowly scans a beam in the x,y. | 18:02 |
| azonenberg | For spam reasons i'm limiting editors to confirmed accounts | 18:02 |
| glowplug` | You did it! Awesome! | 18:03 |
| glowplug` | Account glowplug. =) | 18:03 |
| glowplug` | for email you can use raincloudcomputers@lavabit.com | 18:03 |
| glowplug` | The principle is that although it scans slowly compared to a laser projector. It will fully develop the resist along its path. And the path is any position on the x,y plane. | 18:04 |
| glowplug` | Honestly if it fails it's only because I designed or built it poorly. In principle it will work. | 18:05 |
| Sync_ | azonenberg: that does not resolve for me | 18:05 |
| glowplug` | I'm on the page. =) | 18:05 |
| azonenberg | Sync_: i just made the subdomain like 15 minuts ago | 18:06 |
| azonenberg | dns might not have propagated yet | 18:06 |
| Sync_ | yeah probably | 18:06 |
| glowplug` | I have to go for a bit. See if you guys can hunt down and stalk a telescope maker type. I will try also. | 18:06 |
| soul-d | even my super duper fiber con can't find it yet | 18:07 |
| glowplug` | I'm so lucky. Haha | 18:07 |
| glowplug` | Back in a bit. | 18:07 |
| soul-d | if i had the money i would have made a 1meter scope already | 18:07 |
| soul-d | or few small ones for that matter | 18:08 |
| soul-d | still need guider for my 10" | 18:08 |
| Sync_ | meh | 18:08 |
| soul-d | well plus im lazy to gather all the stuff i think it had to do with ability to damp up the aluminum layer | 18:09 |
| soul-d | or mess about with silver stuff but you need to redo that like every few years | 18:10 |
| Sync_ | if you do not protect the al it will also go dull | 18:11 |
| Sync_ | you can just send the mirror away to a coater and get it coated | 18:11 |
| Sync_ | or if you want get a wideband dielectric coating | 18:13 |
| soul-d | knowing netherlands /europe i better can buy the mirror if there is even company able to do it i know there was a | 18:13 |
| soul-d | place but still size limited | 18:13 |
| Sync_ | a lot of companies do that in europe | 18:14 |
| soul-d | havent looked at it since like 8 years it's that glowplugh mentioned it | 18:14 |
| Sync_ | you could also do it yourself | 18:17 |
| Sync_ | sputtering Al is quite easy | 18:17 |
| azonenberg | Easy? | 18:17 |
| azonenberg | i've heard Al in particular needs very high output powers | 18:17 |
| azonenberg | due to the need to break through the oxide | 18:17 |
| azonenberg | compared to other materials that have less tough oxides | 18:17 |
| Sync_ | yeah you need assloads of power but when you are evaporating it is not that special | 18:17 |
| azonenberg | Evaporating vs sputtering is a big difference :p | 18:18 |
| Sync_ | true, but even sputtering is ok | 18:18 |
| Sync_ | I did not have an issue in my jar | 18:18 |
| azonenberg | i want to build myself a DC sputtering rig | 18:18 |
| azonenberg | How hard do you think that'd be? | 18:18 |
| azonenberg | I have a mechanical roughing pump | 18:18 |
| Sync_ | not very hard | 18:18 |
| azonenberg | but no other vacuum hardware atm | 18:18 |
| Sync_ | I did it in a jam jar | 18:18 |
| azonenberg | Lol | 18:19 |
| Sync_ | that's enough if it can get low enough | 18:19 |
| azonenberg | i think i'd get something a little nicer than that | 18:19 |
| Sync_ | no shit, but lazyness :D | 18:19 |
| Sync_ | now that I have the machines I'll build something more adequate | 18:19 |
| azonenberg | Something like http://www.ebay.com/itm/Bell-Jar-and-Vacuum-Plate-Combo-1-2-gal-/281065244774?pt=LH_DefaultDomain_0&hash=item4170cb4866 | 18:19 |
| azonenberg | combined with a homebrewed baseplate etc | 18:19 |
| azonenberg | then i'd need a gas inlet, HV supply, etc | 18:20 |
| Sync_ | that's a little small | 18:20 |
| azonenberg | That was just an example | 18:20 |
| azonenberg | but bear in mind that i only need to fit a 2" wafer inside at most | 18:20 |
| Sync_ | yeah I don't really like bell jars | 18:20 |
| azonenberg | The option i was thinking of actually was a cylindrical glass tube | 18:20 |
| azonenberg | with flanges and two metal plates | 18:20 |
| Sync_ | well the problem is more or less that you need to have proper clearances for the heat | 18:21 |
| azonenberg | that way i could have the HV coming in from the top | 18:21 |
| Sync_ | even with a cooling loop it is an issue | 18:21 |
| azonenberg | Hmm | 18:21 |
| azonenberg | Could you do it conductively? | 18:21 |
| Sync_ | also glass is annoying to get clean | 18:21 |
| azonenberg | Not it's not | 18:21 |
| azonenberg | http://www.fullam.com/Clean.htm | 18:21 |
| azonenberg | effasol is what they use in the lab at school in the SEM stuff | 18:22 |
| azonenberg | smear it on the inside of the jar | 18:22 |
| Sync_ | not getting it vacuum clean | 18:22 |
| azonenberg | then just apply water and it dissolves, taking the film with it | 18:22 |
| Sync_ | that's easy enough | 18:22 |
| Sync_ | but getting your metals off it once they are there | 18:22 |
| azonenberg | Yes | 18:22 |
| azonenberg | that's what that stuff is for | 18:22 |
| Sync_ | I just don't like it | 18:22 |
| azonenberg | it forms a water-soluble layer on the inside of the glass | 18:22 |
| azonenberg | then it lifts right off | 18:23 |
| Sync_ | interesting | 18:24 |
| Sync_ | I'd probably just RF etch | 18:24 |
| Sync_ | 100% oxygen plasmas are nicely reactive | 18:24 |
| azonenberg | Lol | 18:24 |
| azonenberg | I want that in the longer term | 18:24 |
| Sync_ | I have a xds10 scroll here | 18:24 |
| azonenberg | it would be so cool to be able to do SF6 plasma RIE | 18:24 |
| Sync_ | and two replacement scrolls | 18:24 |
| Sync_ | I'll try and see if I can get a recipient from work | 18:26 |
| azonenberg | http://www.bidservice.com/browses/DHTML_PHOTOS.ASP?ProductID=27227&Mfg=PLASMA+SCIENCES+INC.&Mdl=RIE-200W&InvNum=57484 | 18:26 |
| azonenberg | want | 18:26 |
| Sync_ | wee that thing is tiny | 18:27 |
| azonenberg | Yeah, and $10K | 18:27 |
| azonenberg | i feel like you could build it for a lot less | 18:27 |
| Sync_ | yeah it is not that hard | 18:27 |
| azonenberg | I'd want to wait until i got a "real" lab set up first though | 18:28 |
| Sync_ | I wonder why such small plasma etchers are so spendy | 18:28 |
| azonenberg | Because they can | 18:28 |
| azonenberg | they sell to people with very deep pockets | 18:28 |
| Sync_ | you can get large evap setups for 15k used | 18:28 |
| Sync_ | I mean yeah they sure do but 10k | 18:29 |
| azonenberg | well if i could get SF6 RIE | 18:29 |
| Sync_ | wat | 18:29 |
| azonenberg | i could do nice cutouts in Si | 18:30 |
| azonenberg | then sputter Ta + Cu | 18:30 |
| azonenberg | boom copper damascene :D | 18:30 |
| Sync_ | http://www.ebay.com/itm/251141774300 | 18:31 |
| Sync_ | meh no sensor head | 18:31 |
| azonenberg | http://www.ebay.com/itm/Plasma-Therm-Reactive-Ion-Etching-System-Model-70-Series-/190621250636?pt=LH_DefaultDomain_0&hash=item2c61e9744c | 18:31 |
| Sync_ | interestingly nobody either sells the sensor with the controller or nobody sells the controller with the sensor | 18:31 |
| Sync_ | most also only sell the controller withot the exciter | 18:32 |
| Sync_ | I wonder if I could make my own EIES sensor | 18:33 |
| glowplug | Back. | 18:34 |
| Sync_ | if it had the sensor I'd buy it right away :/ | 18:34 |
| azonenberg | glowplug: you get my email? | 18:34 |
| glowplug | I did but mu is giving me sass. | 18:37 |
| azonenberg | ? | 18:37 |
| Sync_ | hmm | 18:38 |
| glowplug | Mu handles my email. Not sure what it's problem is right now. | 18:38 |
| Sync_ | SF6 RIE has the annoying fluorine in the exhause issue iirc | 18:39 |
| azonenberg | Sync_: Yes, i'd venti t outside :p | 18:39 |
| azonenberg | vent it* | 18:39 |
| glowplug | I've got my login though. =) | 18:39 |
| azonenberg | glowplug: the server cannot send email if you're trying to do a password reset or something | 18:39 |
| azonenberg | i havent configured that | 18:39 |
| glowplug | I'll just use the default password for now. | 18:40 |
| azonenberg | Once you log in you can change it | 18:40 |
| azonenberg | you just cant ask the server to email you a new one | 18:40 |
| glowplug | The problem I was having is that offlineimap pulled your email but mu didn't get it. Super annoying. | 18:40 |
| azonenberg | oh lol | 18:40 |
| Sync_ | wat | 18:40 |
| glowplug | Hardware guy learning emacs. Bumpy road. | 18:41 |
| glowplug | Alright. Under Litho. "Sample alignment optics" | 18:42 |
| glowplug | Supplies. I'll just do some basic things. | 18:43 |
| Action: Sync_ rages a little | 18:43 | |
| glowplug | Whats the rage? Haha | 18:43 |
| azonenberg | Try to copy over whatever you can from the google code wiki | 18:43 |
| azonenberg | i plan to remove most of that wiki so we don't have stuff in two places | 18:43 |
| glowplug | Alright will do. | 18:44 |
| glowplug | Everything under "supplies" are things considered "consumables" correct? | 18:46 |
| azonenberg | yes | 18:47 |
| glowplug | I will be dealing exclusively with things in the Litho category. | 18:47 |
| glowplug | I have absolutely zero experience with everything else. | 18:48 |
| Sync_ | http://www.youtube.com/watch?v=TV5p36-c3R4 this hurts my vacuum self | 18:48 |
| glowplug | This is what I mentioned earlier. | 18:49 |
| glowplug | http://www.youtube.com/watch?v=m3lWKGQuQoc | 18:49 |
| glowplug | Do we need a magnetron? | 18:50 |
| Sync_ | no but magnetron sputtering is nice | 18:50 |
| glowplug | That is stupidly cool... | 18:50 |
| glowplug | Wait. Sputter copper metal onto glass. | 18:51 |
| glowplug | Time to read the wiki.... | 18:51 |
| glowplug | What kind of materials can be deposited via sputtering in a DIY configuration? | 18:54 |
| glowplug | This is a HIPIMS system? | 18:55 |
| azonenberg | With DC sputtering, any metal pretty much | 18:57 |
| azonenberg | with RF, insulators too | 18:57 |
| Sync_ | yay | 18:58 |
| Sync_ | there finally is cheap glass pipe on ebay | 18:58 |
| glowplug | But we still need a spincoater for the photoresist? | 18:58 |
| azonenberg | Yes | 18:59 |
| azonenberg | and probably spin-on dopants | 18:59 |
| azonenberg | unless you want to get into ion implantation | 18:59 |
| glowplug | So many tools.... | 18:59 |
| glowplug | It sounds like a DIY HIPIMS and DIY spincoater is the way to go. | 19:00 |
| glowplug | What is the glass pipe for? | 19:00 |
| Sync_ | temporary vacuum chamber until I get motivated enough to build something proper out of stainless | 19:07 |
| glowplug | There is actually a video of my idea. http://www.youtube.com/watch?v=VjesdQa3mMU | 19:14 |
| glowplug | He is using galvos though which is why it's so wobbly. | 19:14 |
| Sync_ | I wonder if that will lead to issues due to the angular beam direction | 19:15 |
| Action: Sync_ browses his stash of vacuum flanges | 19:18 | |
| glowplug | I thought about that. There exists optics that will take the beam from any angle and deflect downwards. | 19:18 |
| glowplug | It also might not be an issue with a very small work area. Lets say 50x50mm. | 19:20 |
| glowplug | Is 50mw sufficient to expose the resist? | 19:20 |
| Sync_ | laser with a maximum power of 3 W at 514 nm and 300 mW at 457 nm. This high power | 19:21 |
| Sync_ | output can be used for a second harmonic generation, while typical beam power required for | 19:21 |
| Sync_ | the exposure of color-center masks [1] is of the order 100 mW. An electro-optical modulator | 19:21 |
| glowplug | Looks like I might as well use blu-ray then which is way over those power levels. But theres no cost difference. | 19:23 |
| glowplug | I'm fine with that. =) | 19:23 |
| Sync_ | I'd still like to use my tankless water heater | 19:24 |
| glowplug | For which process? | 19:25 |
| glowplug | Under Metalization does "sputter coater" refer to the HIPIMS device? | 19:26 |
| Sync_ | haha no you do not get the joke | 19:26 |
| Sync_ | I have a huge argon laser | 19:26 |
| Sync_ | which basically just is a water heater... | 19:27 |
| glowplug | OH Haha | 19:27 |
| Sync_ | well at least it tells you when it is on | 19:27 |
| glowplug | Speaking of tube lasers. I need to figure out how to frequency stabalize shitty lasers so I don't need one. Think I'm going to attempt it with an FPGA. | 19:28 |
| Sync_ | what do you want to do? | 19:28 |
| glowplug | For the interferometer. | 19:28 |
| Sync_ | use henes | 19:28 |
| Sync_ | they are cheap enough on ebay | 19:29 |
| Sync_ | an fpga is not needed, you just need to control the temperature and the current precisely | 19:29 |
| glowplug | A frequency stabalized dollar store laser is 10% the cost though. =) | 19:29 |
| glowplug | You need many discrete configurations though correct? Such as amplifiers, comparaters ect. | 19:31 |
| glowplug | That could all be integrated into a ~$10 coolrunner type CLPD | 19:31 |
| azonenberg | glowplug: if you can focus it sufficiently a bluray diode is going to be much cheaper | 19:31 |
| azonenberg | Just use short pulses | 19:31 |
| azonenberg | what you want to avoid is using so much power that you ablate the resist :p | 19:32 |
| glowplug | Wait what am I thinking. We don't need the interferometer now correct? | 19:32 |
| glowplug | Assuming I can keep the sample still during exposer. | 19:32 |
| Sync_ | you need a precision current source with a few passives and a pid temperature controller | 19:33 |
| Sync_ | which is just any micro with a high resolution temperature senor | 19:33 |
| Sync_ | if you do a projector you do not need any interferometers | 19:33 |
| Sync_ | they still are for a moving xy stage | 19:33 |
| azonenberg | I think you will still have to do a fixed laser and moving x-y | 19:34 |
| azonenberg | its much easier to move the sample by microns | 19:35 |
| azonenberg | than to try to steer a beam by millionths of a degree | 19:35 |
| Sync_ | yeah | 19:35 |
| glowplug | I can totally steer a beam by millionths of a degree. | 19:35 |
| azonenberg | accurately? :p | 19:35 |
| azonenberg | and repeatably? | 19:35 |
| azonenberg | there's a reason nobody does this | 19:35 |
| glowplug | One person did it. On Youtube. Hahaha | 19:36 |
| azonenberg | With what kind of resolution? | 19:36 |
| glowplug | Horrible. Because he used Galvos. | 19:36 |
| azonenberg | And what do you plan to do | 19:36 |
| glowplug | But steppers with a 200/1 gear reduction should give enough resolution. | 19:36 |
| azonenberg | Lol | 19:36 |
| azonenberg | Do the trig | 19:36 |
| Sync_ | enjoy your backlash | 19:36 |
| azonenberg | If you want 1um shift | 19:36 |
| Sync_ | and yeah do the trig | 19:37 |
| azonenberg | at say a 10cm distance | 19:37 |
| azonenberg | any idea what fraction of a degree that is? :P | 19:37 |
| glowplug | Backlash in the gearbox? I did do the trig but for 10mm above the sample. | 19:37 |
| azonenberg | 10mm? | 19:37 |
| azonenberg | you realize you need room for the optics | 19:37 |
| glowplug | In 1/4 of a second of movement at 200 pulses per second you get 1/4 full rotation. 200 reduction gives you .001 degrees change in that period. | 19:39 |
| azonenberg | Ok | 19:39 |
| azonenberg | 0.001 degrees | 19:39 |
| azonenberg | do you know how huge that is? | 19:39 |
| glowplug | Let me find my notes onesecond. | 19:39 |
| glowplug | I got .048mm travel with 1 second of motor rotation at 10mm from the sample. | 19:40 |
| azonenberg | 48 microns | 19:41 |
| azonenberg | thats huge | 19:41 |
| glowplug | Nope I have 1000/1 reduction here not 200. Thats why. | 19:41 |
| glowplug | Thats for a full second of motor rotation. | 19:41 |
| Sync_ | uhh | 19:41 |
| Sync_ | 1000 times reduction with gears | 19:41 |
| azonenberg | LOL | 19:41 |
| Sync_ | do you know how large that is | 19:41 |
| Sync_ | what the hell are you smoking | 19:41 |
| glowplug | How large 48 microns is? | 19:41 |
| glowplug | That is with a full second of rotation or 200 pulses. | 19:42 |
| azonenberg | 1000:1 reduction... | 19:42 |
| azonenberg | how much backlash is that gonna be at the low end? | 19:43 |
| glowplug | Right. That is with a 4 stage planetary. Laser cut out of acrylic. | 19:43 |
| azonenberg | five or ten revolutions maybe? | 19:43 |
| glowplug | I mean there is going to be backlash no matter what. Whether its in the gearbox or the ball screw. | 19:44 |
| glowplug | At least this way the machine costs $100 total instead of $2,000 to get results. | 19:44 |
| azonenberg | Completely useless results | 19:45 |
| Sync_ | you need to move 5.7µ° | 19:45 |
| glowplug | The only reason it wouldn't have 10 micron repeat accuracy is if the gearbox's were absolutely horrible. | 19:45 |
| glowplug | 5.7u degrees sounds scary. But we have to make adjustments of that accuracy everywhere. Even down to aligning the sample. | 19:46 |
| glowplug | Having a stepper do it isn't that crazy. | 19:46 |
| Sync_ | o.0 | 19:47 |
| Sync_ | I want to see that | 19:47 |
| azonenberg | having a stepper do 175,000 steps per revolution? | 19:47 |
| azonenberg | oh, and that assumes you can fit your optics in 1cm from the sample | 19:47 |
| azonenberg | Which is rather unrealistic especially for a homebrew setup | 19:47 |
| azonenberg | i'd expect more like 10cm | 19:47 |
| Sync_ | I mean shit, it is easier to build an xy table that does that | 19:47 |
| Sync_ | and then you can scan a *very* small area | 19:48 |
| glowplug | No stepper has 175,00 steps per revolution. Thats what the reduction is for. | 19:48 |
| Sync_ | because your focus will deteriorate | 19:48 |
| azonenberg | That was the other reason i wanted to go x-y | 19:48 |
| azonenberg | you dont need to mess with the focus | 19:48 |
| Sync_ | yes but your quad planetary has an assload of play | 19:48 |
| Sync_ | you cannot avoid it | 19:49 |
| Sync_ | that's why there are hypocycloid drives and harmonic drives | 19:49 |
| glowplug | I cannot avoid gear reductions anyways. On a SCARA, Cartesian, doesn't matter. | 19:49 |
| glowplug | Hypocycloid drives are unsuitable due to wobble no? | 19:49 |
| azonenberg | yes, but it's better to move the sample a large distance | 19:49 |
| azonenberg | than a mirror a tiny distance | 19:49 |
| Sync_ | the reduction you need is just unrealistically small | 19:50 |
| Sync_ | or rather large | 19:50 |
| glowplug | If a Hypocycloid drive is suitable I will use that. | 19:50 |
| glowplug | I assumed the offcenter mass would make it useless. | 19:50 |
| Sync_ | you need a good one | 19:50 |
| azonenberg | i still think a Cartesian micrometer screw with a geared stepper is probably the best option | 19:51 |
| glowplug | Ok then I will concede that the 4 stage planetary probably has too much backlash for mirror positioning of that accuracy. | 19:51 |
| azonenberg | and interferometers for positional feedback | 19:51 |
| glowplug | If I can get a hypocycloid drive laser cut and get my 1000/1 with only 2 stages then I think it is work trying. | 19:52 |
| azonenberg | I want to build a Michelson interferometer some time soon just to play with | 19:52 |
| azonenberg | And do the math for how many teeth you'd need on the gears | 19:52 |
| glowplug | That would eliminate any backlash in the system. | 19:52 |
| azonenberg | how big are these gears gonna be? | 19:52 |
| glowplug | I did. With 4 stages that reduction is possible with gears that fit on a NEMA-23 sized stepper. | 19:53 |
| azonenberg | How many teeth | 19:53 |
| glowplug | But I agree that would likely have too much play. | 19:53 |
| azonenberg | And yeah | 19:53 |
| azonenberg | You will want positive feedback | 19:53 |
| azonenberg | and you cant get that with beam steering | 19:53 |
| glowplug | And the hypocycloid drive (if stable) would work. | 19:53 |
| azonenberg | moving the sample, though, allows you to move with the beam blanked | 19:53 |
| Sync_ | are you really expecting lasercut pieces to be accurate enough for that | 19:53 |
| glowplug | For a hypocycloid drive? | 19:54 |
| Sync_ | yes | 19:54 |
| Sync_ | I mean it'll spin | 19:54 |
| Sync_ | but will it really be backlash free? | 19:54 |
| Sync_ | the one I have is wire EDM'd | 19:54 |
| glowplug | All hypocycloid drives are backlash free. | 19:54 |
| glowplug | Just not wobble free. | 19:54 |
| glowplug | And that is something I don't have the answer for. I don't know how much it will wobble. | 19:54 |
| glowplug | The cost difference between my proposed system and the "traditional" is a factor of 50. | 19:55 |
| Sync_ | there are just too many engineering problems with your idea | 19:56 |
| glowplug | I think it is worth persuing even for a short time if the design could enable people to contribute to the project who can't afford a $3000+ setup. | 19:56 |
| glowplug | There are problems. Thats why I brought it up. And my backup plans. | 19:57 |
| glowplug | But I think the hypocycloid gearbox could work if it was designed well enough to not wobble. | 19:57 |
| azonenberg | Sync_: http://www.ebay.com/itm/Manual-Linear-X-Stage-0-5-Inch-100TPI-Thorlabs-T12X-/281053144084?pt=LH_DefaultDomain_0&hash=item417012a414 | 19:57 |
| azonenberg | what do you think of getting that | 19:57 |
| azonenberg | if i want to fool with interferometry | 19:58 |
| azonenberg | specs claim that 400nm movement accuracy is possible and so if i sample at a few KHz i should easily be able to pick up sub-wavelength shifts | 19:58 |
| glowplug | 4 available. | 19:59 |
| glowplug | Those are extremely nice. | 19:59 |
| azonenberg | Well don't buy them before i get some :p | 19:59 |
| Action: azonenberg adds 2 to cart | 19:59 | |
| glowplug | Haha | 20:00 |
| azonenberg | Ordered | 20:00 |
| azonenberg | Seller has good feedback and they're only $35 each | 20:00 |
| azonenberg | even if they arent good enough for fab i have a lot of other uses in mind | 20:00 |
| Sync_ | they are a little small | 20:00 |
| azonenberg | Sync_: bear in mind we're talking about putting a single die on it | 20:01 |
| azonenberg | I actually wanted to use them for microscopy | 20:01 |
| Sync_ | get me the other two azonenberg | 20:01 |
| azonenberg | Sync_: You buy them :P | 20:01 |
| Sync_ | oh he ships world wide | 20:01 |
| Sync_ | that's nice | 20:01 |
| azonenberg | I feel like it should be possible to hook a stepper up to them | 20:02 |
| azonenberg | I want to make an x-y CNC stage for my microscope | 20:02 |
| azonenberg | to do automatic scanning of large areas | 20:02 |
| glowplug | You can send individual pulses to a stepper. The resolution of the machine I described earlier (assuming it could be built) would be 200/48 microns or 240nm. | 20:02 |
| glowplug | So my backup plan. Lets see if I can get it shot down too. | 20:04 |
| glowplug | The SCARA robot. | 20:05 |
| Sync_ | azonenberg: he has a nice xy stage too | 20:05 |
| azonenberg | Sync_: i wanted linear ones for the interferometer experiments | 20:05 |
| azonenberg | i'll look at his other stuff after payday :p | 20:05 |
| glowplug | Actually it suffers from all of the same basic problems as the projector configuration. Plus some others. | 20:05 |
| Sync_ | XY axis RMS repeatability < 0.7 ¼m | 20:06 |
| Sync_ | nice. | 20:06 |
| glowplug | Alright let me put it this way. I'm going to attempt the configuration I described in the off chance it does something useful we would have significantly cheaper litho. If I fail (~97%) then I'm only out a few bucks. | 20:06 |
| azonenberg | for my cnc microscope i dont even need that good | 20:07 |
| azonenberg | i just need to find an area of the sample | 20:07 |
| azonenberg | oh and i need to get my camera working in linux | 20:07 |
| glowplug | In the meantime I will also plan an x/y stage with interferometer feedback ect. ect. | 20:07 |
| glowplug | What type of camera do you have? | 20:07 |
| Sync_ | aah I want that xy stage | 20:09 |
| Sync_ | that would solve all issues :D | 20:09 |
| azonenberg | Sync_: go buy it? | 20:09 |
| Sync_ | yeah I'll do | 20:10 |
| azonenberg | if you dont, in a couple of days i might :p | 20:10 |
| azonenberg | Do you think a cheap pointer-level laser diode from digikey is stable enough to use for some quick fooling around with inteferometry? | 20:11 |
| Sync_ | not so sure | 20:12 |
| glowplug | Yeah there was a video on YouTube I watched last night with a dollor store laser and he got a pretty good pattern. | 20:12 |
| azonenberg | i mean i wouldnt use it for precise measurements | 20:12 |
| azonenberg | but just to fiddle with the technique | 20:12 |
| Sync_ | I read a paper that said it depends on the diode | 20:12 |
| Sync_ | but I'd get a hene | 20:12 |
| azonenberg | For a production system i might | 20:13 |
| glowplug | You probably have to ditch the optics but the cheap diodes should work for experimentation. | 20:13 |
| glowplug | If you have a really good quality current source it will work for sure. | 20:13 |
| azonenberg | This laser has an integrated supply | 20:14 |
| azonenberg | i have no idea how stable it is :p | 20:14 |
| glowplug | I would pull its supply and the optics. | 20:14 |
| azonenberg | its a pointer-style sealed unit | 20:14 |
| glowplug | Yeah | 20:14 |
| soul-d | they did that feynman expiriment thought experiment now btw | 20:14 |
| glowplug | Just hack it up then use your own lense and current source. | 20:14 |
| glowplug | And it will work awesome for a michealson setup. | 20:15 |
| glowplug | The diodes are generally fine with everything else being junk. | 20:15 |
| Sync_ | azonenberg: a hene on ebay should be under 20$ | 20:15 |
| soul-d | http://physicsworld.com/cws/article/news/2013/mar/14/feynmans-double-slit-experiment-gets-a-makeover | 20:15 |
| soul-d | oh | 20:15 |
| azonenberg | One thing at a time lol, i dont have enough time to build the whole thing now | 20:16 |
| soul-d | not the first | 20:16 |
| soul-d | old news :P | 20:16 |
| Sync_ | just saying :D | 20:16 |
| glowplug | The cheapest tubes I could find was a pair of two for $50. | 20:16 |
| glowplug | But who knows what shape they are in. | 20:16 |
| glowplug | The newish looking tubes are ~$75+ | 20:16 |
| Sync_ | just wait and bid | 20:16 |
| Sync_ | I have a few and none was more than 25$ | 20:16 |
| azonenberg | Sync_: are diode lasers just not stable enough for interferometry? | 20:17 |
| glowplug | They are! | 20:17 |
| glowplug | But hene lasers are extremely stable by nature. | 20:17 |
| glowplug | And a frequency stabalized hene laser is near perfect. | 20:17 |
| glowplug | Diode lasers are good for experiment ect. | 20:18 |
| glowplug | One of the best youtube videos from MIT. They make a simple michealson with a diode laser and calculate its wavelength. Very accurate. | 20:19 |
| Sync_ | azonenberg: the beam quality is a lot better | 20:20 |
| azonenberg | Sync_: well i guess one nice thing about HeNe is a known output wavelength | 20:20 |
| Sync_ | that too | 20:21 |
| azonenberg | So you can have numbers measured in nm rather than in wavefronts :p | 20:21 |
| Sync_ | yeah | 20:21 |
| glowplug | The MIT experiment used a 650nm diode and 1/4 transitions were clearly visible. So that is fairly accurate. | 20:22 |
| glowplug | Of course even if the laser was affordable they have top dollar optical equipment. =P | 20:23 |
| glowplug | Yeah what you need to do for the diode laser interferometer is have really good optics and be able to adjust mirror very accurately. | 20:30 |
| Sync_ | one could just measure the wavelength | 20:31 |
| glowplug | Absolutely. It would be a pain compared to hene but fun nonetheless. | 20:31 |
| glowplug | Of course you need to already have a good laser to do that. O.o | 20:33 |
| Sync_ | it would be connecting the fiber to the wavelength meter | 20:33 |
| glowplug | Do you guys really have every cool toy? Haha | 20:33 |
| glowplug | Just so I understand fully. The current prevailing / preferred design of the direct litho. | 20:36 |
| glowplug | It is a moving x,y stage driven by steppers?/servos? with a gear reduction. A mirror on all sides that are monitored by a series of interferometers for position encoding. | 20:37 |
| glowplug | Flip down microscope with a point and shoot cam on the top. Micrometers for manaul adjustment. | 20:38 |
| Sync_ | http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.30.8856&rep=rep1&type=pdf I guess that's what would be the best | 20:40 |
| Sync_ | well if I really wanted a wavelength meter I'd just go to the lab at work | 20:41 |
| glowplug | Reading. This guy gets a good pattern with a radioshack diode. Skip to 5:30 http://www.youtube.com/watch?v=wdasvpErwsc | 20:41 |
| glowplug | That was with manual alignment and no optical table. Pretty good in my opinion. | 20:42 |
| glowplug | There is actually a PDF "laser scanner for direct writing lithography". Their design is quite a bit different than mine but with 1 micron accuracy and claiming that .5 is possible in principle. | 20:49 |
| glowplug | Beam positioning is by modulation not mechanical actuation. Interesting. | 20:51 |
| glowplug | http://en.wikipedia.org/wiki/Acousto-optic_modulator | 20:52 |
| glowplug | Alright so a single HeNe laser gives feedback for both the X and Y. That is interesting. | 20:54 |
| Sync_ | yes | 20:55 |
| glowplug | Did you see the cost estimations for the device? LOL | 20:55 |
| Sync_ | not too bad | 20:56 |
| Sync_ | this is 95 | 20:57 |
| Sync_ | keep that in mind | 20:57 |
| glowplug | We want manual digital control of the stage for positioning correct? | 20:58 |
| glowplug | Analog joystick sort of thing. | 20:58 |
| Sync_ | not really, some kind of pc interface would be nice, linuxcnc would do just fine | 20:59 |
| glowplug | Could just do a custom interface in linuxcnc. | 20:59 |
| glowplug | With the camera output right in the software. | 21:00 |
| Sync_ | you don't even need a custom interface | 21:00 |
| Sync_ | the camera does nothing after you alinged everything | 21:00 |
| glowplug | It would make automatic alignment possible. Thats just a toy though. | 21:01 |
| glowplug | The PDF says servos. I wonder what the gear reduction is. | 21:01 |
| glowplug | So you intend on using hypocycloid gearboxes and servos? | 21:03 |
| Sync_ | no | 21:03 |
| glowplug | What kind of motor configuration? | 21:04 |
| Sync_ | some kind of dc servo with a high resolution encoder | 21:04 |
| glowplug | Won't you need a gearbox? | 21:05 |
| Sync_ | probably, but 10fold would do | 21:05 |
| Sync_ | because the real positioning is done by the interferometer | 21:05 |
| glowplug | I've been working a little on the encoder problem. | 21:06 |
| glowplug | CD's have .5 micron resolution. You could build a very accurate encoder with cdrom guts and a ring with alternating 1-0 pattern written by the burner. | 21:08 |
| glowplug | Could theoretically be millions of steps per rotation. | 21:09 |
| glowplug | The pattern could be written by rigging the burner to be stationary and spinning the ring under it at a set rpm. | 21:10 |
| Sync_ | I'll just buy one | 21:11 |
| glowplug | What resolution do you need? | 21:11 |
| glowplug | How many steps I should say. | 21:14 |
| Sync_ | that depends on the gearing | 21:15 |
| glowplug | Well for example a decent servo driven articulated robot has about 200,000 steps per revolution. | 21:17 |
| glowplug | I'm sure we need more than that. | 21:17 |
| Sync_ | not really, I suspect the guys that make the stage I posted use something around 2800 step/rev wheels | 21:20 |
| glowplug | Then there must be a massive reduction in the x,y stage? | 21:21 |
| Sync_ | ~20-30 I suppose | 21:21 |
| glowplug | So thats 200-300 between the rotational and linear motion. | 21:21 |
| glowplug | Thats 840,000 steps per linear travel. | 21:22 |
| glowplug | Unfortunately I don't know very much about the design of those x,y stages. Does it make any sense to DIY the table itself? | 21:23 |
| Sync_ | no | 21:23 |
| glowplug | I thought you would say that. | 21:24 |
| glowplug | Well at least everybody else appears to be well funded. Haha | 21:24 |
| azonenberg | well funded, lol | 21:24 |
| azonenberg | i'm a grad student | 21:24 |
| azonenberg | after rent and food i have a few $k a year to spend on fun stuff at most | 21:25 |
| glowplug | So it's just Sync_ thats well funded? xD | 21:25 |
| Sync_ | probably | 21:25 |
| glowplug | Hahaha | 21:25 |
| glowplug | Well my encoder discs will be CD's. I'll put the designs on the wiki then hopefully other under-funded people can experiment. =) | 21:26 |
| glowplug | I have fully conceded on the projection configuration. They exist (since 1989 apparently) but the design is not straitforward and there are too many variables that make it too error prone. | 21:27 |
| Sync_ | it's not really that I actually have a lot of money, but when I do I spend it | 21:27 |
| Sync_ | ah nice | 21:29 |
| Sync_ | avago makes 20000imp/r encoders | 21:29 |
| Sync_ | that makes for 80000 counts after quadrature decoding | 21:29 |
| glowplug | How much? | 21:29 |
| Sync_ | good question | 21:29 |
| glowplug | Uh oh. Prices arent on the website. Warning! | 21:30 |
| azonenberg | glowplug: doing it on CDs is nontrivial | 21:30 |
| azonenberg | they include error correcting codes and framing | 21:30 |
| azonenberg | you cant just burn a timecode using regular burner firmware | 21:30 |
| Sync_ | unfortunately they are not avalible anymore | 21:31 |
| Sync_ | but I bet they are around 200$ | 21:31 |
| Sync_ | maybe less | 21:31 |
| Sync_ | BUT they have nice new encoders | 21:32 |
| Sync_ | I'm just trying to figure out what they used in the stage | 21:32 |
| glowplug | Yes I'm still working on that. It would be necessary to digitally modulate the laser diode directly and to read the photodiode output directly bypassing the drives uC. | 21:33 |
| glowplug | In the PDF they say "DC Servo Motors". =( | 21:34 |
| Sync_ | yeah I guess they have a +-4-30 reduction | 21:34 |
| Sync_ | 5 is realistic with encoders avalible at that time | 21:35 |
| Sync_ | glowplug: actually they are not that bad | 21:36 |
| glowplug | We need three of them though. =) | 21:37 |
| Sync_ | two | 21:37 |
| glowplug | Oh right. Then the piezo for the Z which I have no experience with. =( | 21:37 |
| glowplug | How much for disc + encoder? | 21:38 |
| Sync_ | I suppose one could live without autofocus for a while | 21:38 |
| glowplug | Yeah I think autofocus will need to be added later. | 21:39 |
| Sync_ | around 100$ per set | 21:39 |
| glowplug | Hey thats actually not that bad. Digikey must have very bad prices. | 21:39 |
| Sync_ | for a 17bit absolute encoder | 21:39 |
| Sync_ | that's pretty badass | 21:39 |
| glowplug | I'll still take a crack at my CD rom encoders for free each. =) | 21:39 |
| glowplug | We haven't talked about control much. | 21:40 |
| glowplug | If we pipe everything into an FPGA, interferometer output, encoder output, and also use the FPGA for motor control we will have very good latency with very low cost. | 21:41 |
| Sync_ | I'd just rig linuxcnc to it | 21:41 |
| glowplug | LinuxCNC can't be used for encoder feedback loops its too slow. | 21:42 |
| glowplug | There is FPGA motion control IP that will do up to 8 servos with encoder feedback. Just integrate the interferometer output into the control logic. | 21:43 |
| Sync_ | tell that my cnc | 21:44 |
| glowplug | http://www.mesanet.com/fpgacardinfo.html | 21:44 |
| Sync_ | yeah I have a mesa card | 21:44 |
| glowplug | The PC software has 10us latency. Too slow for the actual control loops. | 21:44 |
| glowplug | If you have a mesa card you are all set then. =) | 21:45 |
| Sync_ | that's the easiest solution | 21:45 |
| glowplug | Absolutely. | 21:45 |
| glowplug | Well that was easy. Haha | 21:45 |
| Sync_ | I mean further dicking around is just meh | 21:46 |
| Sync_ | at some point you have to throw money at it | 21:46 |
| Sync_ | we are still talking about positioning to 1µm | 21:46 |
| Sync_ | trying to make a custom drive controller consumes just too much time and effort | 21:47 |
| glowplug | I agree. The mesa unit is actually affordable and adding the interferometer input and control logic won't be difficult at all. | 21:48 |
| glowplug | Imagine if they had mesa cards in 1995. We just replaced $3,000 in equipment with $100. Haha | 21:50 |
| glowplug | Do you have a 6125? | 21:50 |
| Sync_ | oh I'd have to look at my docs | 21:52 |
| Sync_ | I think it is a 5i22 | 21:52 |
| glowplug | For the 6125 (the pci express unit) if you buy 5 they are only $87 each. | 21:52 |
| glowplug | I don't think there are any cost savings to be realized compared to that. O_O | 21:53 |
| glowplug | That unit is quite a bit more expensive. But the 6125 will do everything we need for $87. | 21:55 |
| glowplug | Is a blu-ray diode even accurate enough for 10um devices? | 21:57 |
| azonenberg | The diode, sure | 22:02 |
| azonenberg | you'd need better optics | 22:02 |
| azonenberg | http://ma.ecsdl.org/content/MA2012-02/59/3990.full.pdf#page=1&view=FitH | 22:04 |
| azonenberg | That's the paper i was talking about before | 22:04 |
| azonenberg | under $1k end to end for ~1um resolutoin | 22:05 |
| glowplug | Holy shit in a handbasket. | 22:06 |
| glowplug | That is fantastic. | 22:06 |
| glowplug | Their diode is violet with very low power. Thats great! | 22:07 |
| azonenberg | They're using SU-8 negative resist but you can do the same thing with regular positive resist | 22:07 |
| azonenberg | 405nm diodes work on that too | 22:07 |
| glowplug | I have negative resist sheets thats what I'll be testing with so that works. | 22:08 |
| glowplug | They are using steppers. No mention of gearing. | 22:08 |
| glowplug | They are using the reduction in the x,y stage only??? | 22:08 |
| azonenberg | glowplug: quite possibly | 22:09 |
| azonenberg | these stages will move maybe 100um per rotation | 22:09 |
| azonenberg | so 1-degree precision is submicron | 22:09 |
| glowplug | Ho | 22:09 |
| glowplug | Ly | 22:09 |
| glowplug | Shit | 22:09 |
| glowplug | They dont even have interferometer feedback! | 22:09 |
| glowplug | This is very encouraging | 22:09 |
| azonenberg | That's something you'd put in if you wanted higher resolution | 22:09 |
| azonenberg | the stages i picked up are supposed to be 250um per rotation of the knob | 22:09 |
| azonenberg | 1-degree precision is easily doable with an ungeared stepper | 22:10 |
| glowplug | Sub micron resolution. | 22:10 |
| glowplug | Adjusting micrometers $150. | 22:10 |
| glowplug | So there are steppers controlling the x,y stage. | 22:10 |
| glowplug | The micrometers are where? | 22:11 |
| azonenberg | The stage is probably micrometer screws on the axes | 22:11 |
| azonenberg | that's typical | 22:11 |
| glowplug | I see. So they added the micrometers TO the stage. | 22:12 |
| glowplug | Attached steppers to the micrometers. | 22:12 |
| azonenberg | the micrometers probably shipped with the stage | 22:12 |
| glowplug | So all adjustment is done in sfotware. | 22:12 |
| glowplug | *software | 22:12 |
| azonenberg | a high-precision stage without micrometers is pretty useless | 22:12 |
| azonenberg | And for that design it does seem like it's all open-loop contorl | 22:12 |
| azonenberg | control* | 22:12 |
| glowplug | Have you seen these? | 22:13 |
| glowplug | http://hackteria.org/wiki/index.php/DIY_microscopy | 22:13 |
| glowplug | It is open loop. But there is very little load on the steppers. | 22:14 |
| glowplug | For submicron though I would think that encoded servos are more reliable. | 22:14 |
| azonenberg | Submicron is a whole other animal | 22:14 |
| glowplug | Haha | 22:14 |
| azonenberg | At that point i might think about switching from laser to e-beam | 22:14 |
| azonenberg | or alternatively using nearfield optics | 22:15 |
| azonenberg | Neither is easy | 22:15 |
| azonenberg | But ~1um with lasers should be very doable | 22:15 |
| glowplug | A lot of these costs can be even further reduced. | 22:18 |
| glowplug | Still need ~$100 for the blu-ray laser + lens. | 22:19 |
| glowplug | But you can save $50 on the controller, $300 on the stage + micrometers, Digital microscope can be made for ~$30 thats another $120 savings. | 22:20 |
| glowplug | Based on these numbers it can probably be done for ~$400 total. | 22:21 |
| azonenberg | microscope for $30? | 22:24 |
| azonenberg | lol | 22:24 |
| azonenberg | i dont think so | 22:24 |
| azonenberg | you cant even get a good objective for that much | 22:24 |
| Sync_ | yeah I'm not a huge fan of that design | 22:24 |
| Sync_ | it sure does work but it's openloop | 22:25 |
| glowplug | The webcam design? | 22:25 |
| azonenberg | Sync_: I like their design but i feel like it can be improved quite a bit | 22:25 |
| azonenberg | i'd want to clone it first | 22:25 |
| Sync_ | yeah the idea is great | 22:25 |
| glowplug | Oh the entire stage. | 22:25 |
| azonenberg | then add closed-loop feedback | 22:25 |
| glowplug | I agree with closed-loop. Thats pretty much a no brainer. | 22:25 |
| glowplug | Do you have a link to the sort of microscope optics that would be suitable? | 22:25 |
| Sync_ | meh do I really have to fire up the vpn for access | 22:26 |
| azonenberg | I'd use an Olympus objective from ebay | 22:26 |
| azonenberg | machine a custom tube | 22:26 |
| glowplug | You keep getting kicked? =( | 22:27 |
| azonenberg | then use a nicer camera, maybe a HD webcam | 22:27 |
| Sync_ | oh | 22:27 |
| Sync_ | reminds me | 22:27 |
| glowplug | I suppose the worlds view of our progress will be through that microscope. | 22:27 |
| Sync_ | microscope | 22:27 |
| glowplug | So that is probably a good idea. | 22:27 |
| azonenberg | Well | 22:28 |
| azonenberg | you want to use a nicer one for inspection | 22:28 |
| azonenberg | this would be just for alignment | 22:28 |
| azonenberg | Actually, screw that | 22:28 |
| azonenberg | you might not even need the uscope | 22:28 |
| azonenberg | if you're doing direct write | 22:28 |
| azonenberg | to make masks | 22:28 |
| Sync_ | yeah | 22:28 |
| azonenberg | you can forget about alignment since once etched the mask wil then be used in a contact aligner | 22:28 |
| Sync_ | no need to align anything | 22:28 |
| glowplug | The scope is for calibrating the machine. | 22:29 |
| glowplug | It wont work correctly the first go. | 22:29 |
| glowplug | And also uploading images / video to the wiki. | 22:29 |
| azonenberg | You will want another scope for inspection of work | 22:29 |
| azonenberg | the one on there won't be a nice one you can actually use for general imaging | 22:30 |
| glowplug | How much will the "actual" scope cost? | 22:30 |
| azonenberg | I got mine on ebay for $250 + $250 + $50 | 22:30 |
| azonenberg | body, head, and illuminator respectively | 22:30 |
| glowplug | O.U.C.H. | 22:30 |
| Sync_ | that's not a lot | 22:31 |
| azonenberg | that's a lot? | 22:31 |
| azonenberg | lol | 22:31 |
| Sync_ | to put that in perspective | 22:31 |
| azonenberg | New, it was probably five or ten grand | 22:31 |
| azonenberg | $500ish is dirt cheap | 22:31 |
| Sync_ | shit I have spent over 4k on my mill | 22:31 |
| Sync_ | so what. | 22:31 |
| glowplug | One thing you guys have to realize. | 22:31 |
| glowplug | The cheaper this stuff is the more people can contribute. | 22:31 |
| glowplug | There is a cascading effect of money and support to a project. | 22:32 |
| azonenberg | It's never going to get to the point of being home-PCB-etching availability | 22:32 |
| azonenberg | I'm shooting for "affordable by a hackerspace" | 22:32 |
| azonenberg | Or by a sufficiently insane hobbyist | 22:32 |
| glowplug | But it can get down to "enthousiest garage fab shop with a modest income". | 22:32 |
| glowplug | Right. That seems a good target. | 22:32 |
| glowplug | But equipment under $2000 total (for everything) is probably realistic for that goal. Not $20,000 total. | 22:33 |
| Sync_ | wat | 22:33 |
| azonenberg | $2000? Lol | 22:33 |
| azonenberg | $10K is more what i was hoping to, after lots of tuning | 22:33 |
| azonenberg | the prototype stuff will probably cost me more like 50k | 22:33 |
| Sync_ | 30k is a good starting point imho | 22:33 |
| Sync_ | which is affordable for a hackersapce | 22:33 |
| Sync_ | ~space even | 22:33 |
| glowplug | The spincoater can be made for ~$100. These guys have litho 1um litho with ~$500 in parts. | 22:33 |
| azonenberg | well, once i get out of school | 22:34 |
| azonenberg | high on my list of major purchases is a secondhand FESEM | 22:34 |
| glowplug | $500 for a good microscope. | 22:34 |
| Sync_ | oh yes azonenberg | 22:34 |
| glowplug | We are at $1,100. What other major components are absolutley necessary? | 22:34 |
| Sync_ | they can be had quite cheaply | 22:34 |
| azonenberg | glowplug: Consumables | 22:34 |
| Sync_ | yeah comsumables | 22:34 |
| Sync_ | vacuum parts | 22:34 |
| azonenberg | Dopants from emulsitone are $500 each for P and N type | 22:34 |
| azonenberg | or is it $250? | 22:34 |
| azonenberg | that much again for undoped spin-on-glass | 22:34 |
| azonenberg | $300ish for a bottle of photoresist | 22:35 |
| Sync_ | photoresist | 22:35 |
| azonenberg | HMDS can be had cheap in small volume | 22:35 |
| azonenberg | trace metal grade TMAH | 22:35 |
| Sync_ | a wafer is 10-30$ | 22:35 |
| azonenberg | not sure what the going rate on that is | 22:35 |
| Sync_ | I guess tmah can be cheap | 22:35 |
| Sync_ | but in small units hmm | 22:35 |
| Sync_ | dunno | 22:35 |
| Sync_ | I'd say 5k minimum for a basic setup | 22:36 |
| Sync_ | access to a machine shop is neccessary tho | 22:36 |
| azonenberg | Yeah | 22:37 |
| glowplug | For consumables we can order in volume then do pre-packaged kits for the community. | 22:38 |
| glowplug | You get the economy of scale plus the cost to each hobbyist is very low. | 22:38 |
| glowplug | The vacuum is for which process? How strong of a vacuum? | 22:39 |
| Sync_ | seriously, this is not the kind of thing you can pull off with a tutorial | 22:39 |
| Sync_ | vacuum for any kind of metal deposition or plasma etching | 22:39 |
| azonenberg | And for evaporation you need 1E-6 torr range | 22:39 |
| glowplug | No I don't think tutorial. I think there are enough hobbyists out there with general knowledge of this stuff but thinking that its completely out of reach without school / work equipment. | 22:39 |
| azonenberg | so diffusion pump range at best | 22:39 |
| glowplug | They just need to be proven wrong. | 22:40 |
| Sync_ | plasma etching wants 10^-2mbar and evap 10^-4 or better preferrably | 22:40 |
| azonenberg | Sputtering can be done as high as 30mtorr but that's after you have a good argon purge | 22:40 |
| azonenberg | So you need to get the chamber down quite a bit lower first | 22:40 |
| glowplug | What is the plasma etching for? This is the part of the process that I now nothing about. | 22:40 |
| azonenberg | I was initially hoping to get 10um features working with just wet etches | 22:40 |
| glowplug | *know | 22:40 |
| azonenberg | that might be wishful thinking | 22:40 |
| azonenberg | i've done 20 with wet etches experimentally and they worked fine, though i had some adhesion problems here and there | 22:41 |
| Sync_ | http://www.ebay.de/itm/170969782066 | 22:42 |
| Sync_ | that's quite a good deal for the parts | 22:42 |
| Sync_ | three ion pumps, all the CF hardware | 22:43 |
| azonenberg | Sync_: but not as a SEM | 22:43 |
| Sync_ | yeah | 22:43 |
| Sync_ | just browsing general vacuum stuff | 22:43 |
| Sync_ | too lazy to study :D | 22:43 |
| azonenberg | http://www.ebay.com/itm/Jeol-JSM-6100-Scanning-Electron-Microscope-/140920321161?pt=LH_DefaultDomain_0&hash=item20cf817489 | 22:43 |
| glowplug | The guy on Youtube with the diy magnetron. What was his vacuum source? | 22:44 |
| Sync_ | refridgeration vac pump | 22:44 |
| Sync_ | http://www.ebay.de/itm/Hitachi-S-415A-Scanning-Electron-Microscope-/230456436123?pt=LH_DefaultDomain_0&hash=item35a846259b | 22:44 |
| glowplug | Is that sufficient for everything we need? | 22:44 |
| azonenberg | Was that the guy who had all kinds of problems getting deep enough vacuum? | 22:44 |
| Sync_ | that's probably ok | 22:44 |
| azonenberg | oxygen contamination everywhere? | 22:44 |
| Sync_ | yeah everything oxidized | 22:44 |
| Sync_ | no glowplug by far not | 22:45 |
| azonenberg | Sync_: oh http://www.ebay.com/itm/Jeol-840-Scanning-Electron-Microscope-/270432223960?pt=LH_DefaultDomain_0&hash=item3ef70442d8 | 22:45 |
| azonenberg | I trained on that same setup lol | 22:45 |
| Sync_ | oh | 22:45 |
| Sync_ | snap! | 22:45 |
| Sync_ | we have one too | 22:45 |
| Sync_ | :D | 22:45 |
| azonenberg | an 840? | 22:45 |
| Sync_ | yep | 22:45 |
| azonenberg | Lol nice | 22:45 |
| glowplug | I see that. Copper oxides on the slide. | 22:45 |
| Sync_ | it's our oldest one | 22:45 |
| azonenberg | Sync_: same here | 22:45 |
| azonenberg | The JSM-6335 is the one i've used more recently | 22:46 |
| azonenberg | it's a FESEM | 22:46 |
| azonenberg | $20/hr more to use but thats not a huge deal | 22:46 |
| azonenberg | then if you're made of money you can use the Zeiss in the cleanroom :p | 22:46 |
| Sync_ | we can use all the equipment for free | 22:46 |
| glowplug | So what processes require vacuum that are *Absolutely* necessary for a 10um device? | 22:46 |
| azonenberg | glowplug: Metal deposition | 22:47 |
| Sync_ | metalization | 22:47 |
| azonenberg | You can use spin-on dielectrics and wet etching for large features | 22:47 |
| azonenberg | so no need for RIE, PECVD, etc | 22:47 |
| glowplug | Alright so wet etching refers to using the spincoater for metal deposition. That I get now. | 22:47 |
| azonenberg | No | 22:47 |
| Sync_ | pecvd is something that is not happening with my pumps :D | 22:47 |
| Sync_ | too much ugly stuff involved | 22:47 |
| azonenberg | it refers to etching stuff using a liquid acid | 22:47 |
| azonenberg | rather than a plasma | 22:47 |
| glowplug | What are spin on dialectrics? | 22:47 |
| azonenberg | Which means it can be done at atmospheric pressure | 22:48 |
| azonenberg | glowplug: stuff like http://www.emulsitone.com/sif.html | 22:48 |
| azonenberg | I suggest you learn more about semiconductor fab in general | 22:48 |
| glowplug | I'm reading nonstop already. I just discovered this stuff a week ago. Haha | 22:48 |
| azonenberg | Then work on how to scale it down to hobbyist level | 22:48 |
| Sync_ | the second hitachi I posted seems to be ok | 22:48 |
| Sync_ | it's no fesem for sure but it'll do | 22:49 |
| azonenberg | Sync_: an 840 would be nice to have at home as long as i could rent time on a nicer scope when i needed it | 22:49 |
| glowplug | But I mostly focused my research so far on the litho because I understand those principles well. | 22:49 |
| azonenberg | Sync_: But stuff like http://i.imgur.com/esVwLlK.jpg | 22:49 |
| azonenberg | i dont think you'll get that kind of resolution with an 840 | 22:49 |
| Sync_ | probably not | 22:50 |
| glowplug | It was already determined that the wet etching is not very reliable with devices smaller than 10um correct? | 22:50 |
| azonenberg | the round dots are 60nm nominal colloidal silica left over from from CMP | 22:50 |
| azonenberg | the device is a 45nm FPGA | 22:50 |
| Sync_ | hehe nice | 22:50 |
| azonenberg | glowplug: I forget when industry stopped using wet etches | 22:50 |
| azonenberg | For submicron i'd definitely want to use plasma | 22:50 |
| azonenberg | possibly sooner | 22:50 |
| Sync_ | but if you are into that you can just buy one, reverse engineer shits and pay it off | 22:50 |
| glowplug | And the magnetron is enough for every metalization step for a device correct? | 22:51 |
| azonenberg | Sync_: i'm the guy behind siliconpr0n.org :p | 22:51 |
| Sync_ | yes I know | 22:51 |
| azonenberg | glowplug: The full suite of film coating capabilities you'll want | 22:51 |
| Sync_ | but if you wanted to do that commercially | 22:51 |
| azonenberg | is spin coating, DC sputtering, RF sputtering, evaporation, and PECVD | 22:51 |
| azonenberg | all but the first require vacuum | 22:51 |
| azonenberg | You can probably live without PECVD if you do reactive sputtering for dielectrics, or use spin-on glass | 22:52 |
| glowplug | The PECVD we don't need immediately correct? What about evaporation? That is a different device from the magnetron? | 22:52 |
| azonenberg | Evaporation and sputtering might be able to use the same chamber depending on how you design it | 22:52 |
| azonenberg | the processes are different but they have some similarities | 22:52 |
| azonenberg | DC and RF sputtering can definitely share the chamber | 22:52 |
| glowplug | So a well designed chamber will take care of every vacuum process. | 22:53 |
| azonenberg | Not necessarily | 22:53 |
| glowplug | Then you have litho and the spin coater. | 22:53 |
| Sync_ | http://www.ebay.de/itm/HITACHI-S-800-SEM-REM-FE-SEM-ELECTRON-MICROSCOPE-EDS-EDX-X-RAY-ANALYSIS-/230944048265?pt=DE_Computer_Elektronik_Foto_Camcorder_Optik&hash=item35c5568489 | 22:53 |
| Sync_ | shits | 22:53 |
| Sync_ | I want | 22:53 |
| glowplug | Thats only three primary devices. | 22:53 |
| azonenberg | Sync_: *drool* | 22:53 |
| azonenberg | glowplug: well litho is not one tool | 22:53 |
| glowplug | I mean three main monolithic tools. | 22:53 |
| azonenberg | you need both the direct-write system for mask making and then the contact aligner | 22:53 |
| glowplug | Ahh right. For exposure to the mask. So that is 4 primary tools then. | 22:54 |
| glowplug | *through the mask | 22:54 |
| azonenberg | Then general lab glassware etc for wet processing | 22:54 |
| azonenberg | microscope for in-process inspection | 22:54 |
| azonenberg | If you're doing copper metalization or multiple metal layers CMP would be helpful | 22:54 |
| glowplug | Right. ~$500 scope for checking work. | 22:54 |
| glowplug | So for an absolute bare-bones lab. | 22:55 |
| azonenberg | But for a simple 1-metal process using evaporated aluminum you could get away without CMP | 22:55 |
| glowplug | $200 spincoater, $500 litho, $500 scope, $200 exposure setup, $XXX magnetron? | 22:55 |
| azonenberg | For bare bones you'd want the spin coater, laser direct write for masks, contact aligner, and an evaporator | 22:55 |
| azonenberg | I would do evaporation as the first vacuum tool | 22:55 |
| Sync_ | yeah | 22:55 |
| Sync_ | it is the easiest | 22:55 |
| azonenberg | it needs deeper vacuum but you dont need to add gas to it | 22:55 |
| azonenberg | its basically just a light bulb | 22:56 |
| Sync_ | still around 1k realistically | 22:56 |
| azonenberg | that happens to have somethign stuck to the filament | 22:56 |
| glowplug | The evap is ~$1k? | 22:56 |
| azonenberg | You could use spin-on dielectrics | 22:56 |
| azonenberg | so the evap would only be for metal | 22:56 |
| Sync_ | and even 500 for a microscope is quite a bargain | 22:56 |
| azonenberg | Sync_: yeah, i got lucky | 22:56 |
| azonenberg | asking price was 500 each on body and head | 22:56 |
| Sync_ | I know | 22:56 |
| Sync_ | :D | 22:56 |
| azonenberg | i bargained them down | 22:56 |
| azonenberg | Oh, and then a furnace for implants | 22:56 |
| Sync_ | or oxides | 22:57 |
| azonenberg | I'd do spin-on glass | 22:57 |
| azonenberg | since you'd need that for an ILD anyway | 22:57 |
| glowplug | Does the furnace need vacuum? | 22:57 |
| Sync_ | (then an AFM for measureing the thicknesses) ;) | 22:57 |
| azonenberg | might as well use it for field oxide | 22:57 |
| azonenberg | glowplug: No vacuum, but it might be nice to purge it with inert gas | 22:57 |
| azonenberg | argon or something | 22:57 |
| azonenberg | if you are trying to heat and not oxidize | 22:57 |
| glowplug | I think I've seen nitrogen used. | 22:57 |
| Sync_ | yeah but the inert gas needs to be fairly clean | 22:57 |
| azonenberg | Yeah | 22:57 |
| Sync_ | which has been the issue for us | 22:57 |
| azonenberg | and all of the chemicals have to be completely metal-free | 22:58 |
| glowplug | So the evap is ~$1k? | 22:58 |
| Sync_ | we tried and we got oxide | 22:58 |
| Sync_ | yeah | 22:58 |
| Sync_ | abou that | 22:58 |
| Sync_ | the scope too | 22:58 |
| azonenberg | Sync_: Thats why i want to focus on MEMS first | 22:58 |
| Sync_ | if you calculate with bargains that are possible | 22:58 |
| Sync_ | and not 1 in 100 bargains | 22:58 |
| Sync_ | yeah | 22:58 |
| glowplug | And you think the $1k scope is absolutely necessary to check work at ~10um? | 22:58 |
| Sync_ | I know why you want to do that azonenberg ;) | 22:58 |
| Sync_ | yes | 22:58 |
| glowplug | Alright so we need to narrow down the oven cost. | 22:59 |
| glowplug | ~$200? | 22:59 |
| Sync_ | as I said, around 5k is a _realistic_ starting price | 22:59 |
| azonenberg | glowplug: LOL | 22:59 |
| azonenberg | 200? | 22:59 |
| azonenberg | this is not an oven | 22:59 |
| azonenberg | its a furnace | 22:59 |
| azonenberg | you have to get up to around 1200C | 22:59 |
| Sync_ | I got my ceramic burning oven for 50 | 22:59 |
| azonenberg | Sync_: metal-free? :p | 22:59 |
| Sync_ | but it's not for that | 22:59 |
| Sync_ | haha sure not | 22:59 |
| Sync_ | :D | 22:59 |
| azonenberg | A new one from MTI is probably gonna run you about a grand | 23:00 |
| azonenberg | Do you think AL2O3 insulation is safe for CMOS? | 23:00 |
| Sync_ | I could make a SI insert | 23:00 |
| Sync_ | yep | 23:00 |
| glowplug | Is it possible to get to 1200C with a DIY unit? | 23:00 |
| azonenberg | http://www.mtixtl.com/compactmufflefurnace4x4x410lupto1200cwith30segmentsprogrammableandgasports.aspx | 23:00 |
| glowplug | Induction cant be used can it? | 23:00 |
| azonenberg | This is what i was looking at | 23:00 |
| Sync_ | oh hmm | 23:00 |
| Sync_ | let me ask our techs tomorrow | 23:00 |
| azonenberg | Sync_: you think that one would be cmos-compatible if you were careful about only putting freshly RCA-cleaned silicon in it? | 23:00 |
| glowplug | You can get to 1200C with induction for pennies. | 23:01 |
| Sync_ | we had all sorts of shits going on in our ovens | 23:01 |
| azonenberg | Sync_: lol | 23:01 |
| azonenberg | well high-temp processes are where the worst ion contamination happens | 23:01 |
| glowplug | I dont know if it would just blow up the sample or something. | 23:01 |
| Sync_ | we have a company in the institute that does ovens | 23:01 |
| Sync_ | you cannot use induction | 23:01 |
| glowplug | Your positive? | 23:01 |
| Sync_ | yes | 23:01 |
| glowplug | Well that sucks. =( | 23:01 |
| Sync_ | you could use induction to heat the sides of the oven | 23:02 |
| glowplug | Good point. Then heating from the oven itself to the sample would be by convection. | 23:02 |
| Sync_ | convection at over 900°C? | 23:02 |
| Sync_ | not so much | 23:02 |
| azonenberg | more radiation i'd think | 23:02 |
| Sync_ | yeah | 23:02 |
| glowplug | Does that work? | 23:03 |
| glowplug | From induction to radiation heating? | 23:03 |
| glowplug | What kind of material would the oven be? | 23:03 |
| glowplug | Steel? | 23:03 |
| Sync_ | something ferrous | 23:03 |
| glowplug | Iron oven? | 23:03 |
| Sync_ | actually azonenberg I think we use si wafercarriers | 23:03 |
| azonenberg | you'd have to be really careful about metal particles falling out and landing on the samples | 23:04 |
| Sync_ | and quartz holders for those | 23:04 |
| azonenberg | Sync_: i was thinking quartz boarts | 23:04 |
| Sync_ | yep | 23:04 |
| azonenberg | the question is whether being near hot Al2O3 is dangerous to transistors | 23:04 |
| azonenberg | i wouldn't actually have them touching | 23:04 |
| Sync_ | well it is used as gate dielectric | 23:04 |
| Sync_ | so | 23:04 |
| azonenberg | But that's post-diffusion righht? | 23:05 |
| azonenberg | the big time you have metal issues is just before an implant or oxidation bake | 23:05 |
| Sync_ | yeah | 23:05 |
| azonenberg | after that, no more furnace | 23:05 |
| azonenberg | just whatever heating you get during an etch or deposition step | 23:05 |
| glowplug | I think that a 10kw powerstage is enough. | 23:06 |
| azonenberg | You realize that you can only pull around 2kW from an average (American) mains circuit, right? | 23:07 |
| glowplug | This is for garages and hackerspaces. | 23:07 |
| Sync_ | azonenberg: it seems to be safe | 23:07 |
| glowplug | They can figure out how to draw 10kw. EV chargers do. | 23:07 |
| glowplug | It's not like the $1,000 oven draws much less anyways. | 23:07 |
| glowplug | Yeah 10kw is enough. That much power can heat to 1100C in 9 seconds. | 23:09 |
| Sync_ | wat | 23:09 |
| glowplug | http://www.youtube.com/watch?v=UdNHIV5tKbE | 23:09 |
| Sync_ | yeah uh well a nut | 23:10 |
| glowplug | We need to heat the sample overnight correct? | 23:10 |
| azonenberg | glowplug: For diffusions normally an hour or so | 23:10 |
| Sync_ | hmm | 23:11 |
| Sync_ | I guess you could make a sled for the wafer out of quartz | 23:11 |
| glowplug | If we need to ramp up to 1200C and down again within an hour. I think it can be done with a 10kw powerstage, some copper, and an iron box. | 23:11 |
| Sync_ | so that metals do not affect you that much | 23:11 |
| Sync_ | now that is another thing you have to develop | 23:11 |
| Sync_ | a 10kW smps is not easy | 23:12 |
| Sync_ | let alone a 10kW induction heater | 23:12 |
| Sync_ | the tank caps are quite spendy | 23:12 |
| Sync_ | the currents involved are large | 23:12 |
| glowplug | It may be the case that 10kw is actually very overpowered. | 23:13 |
| Sync_ | yes | 23:13 |
| glowplug | Do we know the power draw from the retail furnaces at the wall? | 23:13 |
| Sync_ | the one azonenberg had uses 700W | 23:13 |
| glowplug | OH | 23:14 |
| glowplug | Then the induction version should have comparable power usage. | 23:14 |
| glowplug | Could just use an ATX SMPS | 23:14 |
| Sync_ | ... | 23:14 |
| Sync_ | yeah right | 23:14 |
| Sync_ | did you actually build a induction heater before? | 23:14 |
| glowplug | I understand their principles. | 23:15 |
| Sync_ | http://www.centrotherm.de/uploads/tx_kchnewproduct/Oxidator_Boot_Wafer_02.jpg azonenberg | 23:15 |
| Sync_ | understanding their principles does not show you the pain to make one | 23:15 |
| glowplug | It looks like it can be done without an SMPS at all. | 23:17 |
| Sync_ | it *is* a smps | 23:18 |
| glowplug | In this design I don't see any IGBT's / FETs. | 23:19 |
| glowplug | http://www.mindchallenger.com/inductionheater/ | 23:19 |
| Sync_ | a smps does not need igbts or fets | 23:20 |
| Sync_ | it can also use bipolars or thyristors | 23:20 |
| glowplug | I dont think there are any switches. | 23:20 |
| Sync_ | oh sure | 23:20 |
| Sync_ | otherwise it would not work | 23:20 |
| glowplug | I'm looking! | 23:20 |
| glowplug | So far I just see diodes. | 23:21 |
| glowplug | And a massive bank of caps. | 23:21 |
| Sync_ | it starts at page 10 | 23:21 |
| glowplug | Got it! | 23:22 |
| glowplug | I'm not sure that these FET's are switching 10kw however. | 23:22 |
| Sync_ | they could | 23:22 |
| Sync_ | they are not but they could | 23:22 |
| glowplug | This is an interesting design. | 23:23 |
| glowplug | The FET's are switching AC? | 23:23 |
| Sync_ | they receive dc | 23:24 |
| Sync_ | and make ac out of it | 23:24 |
| glowplug | Ahh ok I thought it was a solid state AC voltage regulator. | 23:24 |
| glowplug | So we are positive that a furnace with gas purging and 1200C max temp is available for $1000? | 23:27 |
| Sync_ | about that | 23:28 |
| glowplug | The DIY option is probably in the $300 range + ~100 hours labor. | 23:28 |
| glowplug | Maybe less. Hard to say. | 23:28 |
| glowplug | Plus misc and consumables thats hovering at $4500-$5000 | 23:29 |
| glowplug | For an absolute basic setup | 23:29 |
| glowplug | Those numbers are with the retail furnace. | 23:30 |
| Sync_ | yeah what I said basically | 23:32 |
| glowplug | I wonder if it is realistic to complete a device in a distributed way. I do the litho, mail out to doping, mails out to oven, ect. ect. | 23:32 |
| glowplug | It would be slow but maybe possible. | 23:32 |
| Sync_ | some processes cannot have a lot of time between them | 23:33 |
| Sync_ | because of oxidation and contamination | 23:33 |
| glowplug | Ahhh yeah. | 23:33 |
| glowplug | Plus USPS likes to drop kick packages. | 23:33 |
| glowplug | Litho can be outsourced but everything else is probably best kept in a single lab. | 23:34 |
| Sync_ | well mask making can be outsourced | 23:34 |
| Sync_ | otherwise it takes ages | 23:34 |
| glowplug | By outsourced I mean one hobbyist makes a set of masks then mails those out to another hobbyist with the lab. | 23:35 |
| Sync_ | yeah but you could also get commercial masks | 23:35 |
| Sync_ | it's the same thing basically | 23:35 |
| glowplug | Absolutely. | 23:35 |
| glowplug | Agreed. Just the price difference. And quality. Haha | 23:35 |
| glowplug | What is your opinion about the PDF litho setup with the steppers? Asside from obviously switching to closed loop servos. What about the lack of interferometer feedback? | 23:37 |
| glowplug | Maybe thats something we can add later? | 23:37 |
| Sync_ | yeah | 23:37 |
| glowplug | Thinking the same thing. | 23:37 |
| glowplug | I have a way way way better picture of whats going on now. | 23:38 |
| glowplug | Is the furnace considered FEOL? | 23:40 |
| glowplug | Is it its own category? | 23:40 |
| azonenberg | Furnace is probably FEOL since its not used once you put down metal | 23:40 |
| glowplug | Alright I'll add to the wiki. =) | 23:40 |
| glowplug | What else is FEOL? | 23:41 |
| azonenberg | Everything that happens before you put down the first metal layer | 23:42 |
| glowplug | That would include Litho then. | 23:42 |
| azonenberg | I'd file litho separately | 23:42 |
| azonenberg | since its done everywhere | 23:42 |
| glowplug | Good point. | 23:42 |
| glowplug | So for a basic setup there isn't much FEOL then. | 23:42 |
| azonenberg | Not too much, since we arent doing ion implantation etc | 23:43 |
| azonenberg | The acronyms stnad for "front end of line" and "back end of line" respectively btw | 23:43 |
| azonenberg | in reference to the order wafers normally go through the tools during fab | 23:43 |
| glowplug | Yup. =) | 23:43 |
| glowplug | Just burned through the wikis. | 23:44 |
| glowplug | These are the parts I knew *zero* about. Haha | 23:44 |
| glowplug | So the contact mask aligner and sample alignment optics are part of the same apparatus correct? | 23:45 |
| azonenberg | Yes | 23:45 |
| azonenberg | Initially we'll do manual alignment | 23:45 |
| glowplug | At this stage we are aligning the sample to be exposed in UV through the resist. | 23:45 |
| glowplug | *mask | 23:45 |
| azonenberg | Mask is to be clamped in place firmly | 23:45 |
| azonenberg | so we just need an x-y-theta stage | 23:45 |
| azonenberg | (manual) | 23:45 |
| azonenberg | with a relatively imprecise Z axis | 23:45 |
| azonenberg | Move the wafer up to just below the mask | 23:46 |
| azonenberg | line it up | 23:46 |
| azonenberg | bring it up into contact | 23:46 |
| glowplug | Right it needs pan and tilt also. :/ | 23:46 |
| azonenberg | slide the microscope off and load the exposure lamp | 23:46 |
| azonenberg | Nop[e | 23:46 |
| azonenberg | nope* | 23:46 |
| azonenberg | Just rotation | 23:46 |
| glowplug | Ohh I see. Derp. | 23:46 |
| azonenberg | As long as you machine things such that the stage and the mask are sufficiently parallel | 23:46 |
| azonenberg | you just need to line up two in-plane images | 23:46 |
| glowplug | This apparatus also needs a small vacuum correct? | 23:47 |
| Sync_ | pfft no fancy thing as 3d capacitors like we have on dram now? ;D | 23:47 |
| glowplug | OR are we just bolting the sucker down? | 23:47 |
| azonenberg | Light vacuum for the chuck to hold the wafer down is helpful | 23:47 |
| azonenberg | but that's nothing | 23:47 |
| azonenberg | any pump can do that | 23:47 |
| azonenberg | Same with the spin coater | 23:47 |
| glowplug | Right. | 23:47 |
| azonenberg | You could potentially even just use double-stick tape | 23:47 |
| azonenberg | but vacuum is less likely to damage stuff | 23:47 |
| glowplug | Agreed. And the tape is probably more expensive. | 23:47 |
| glowplug | So the microscope for this apparatus. | 23:48 |
| Sync_ | I guess getting the wafer off is quite tricky | 23:48 |
| glowplug | Expensive unit or cheap unit? | 23:48 |
| azonenberg | relatively nice | 23:48 |
| azonenberg | But you only need one objective | 23:48 |
| azonenberg | not a full set | 23:48 |
| glowplug | ~$200 optics? | 23:49 |
| Sync_ | I guess you could use a single optic microscope | 23:49 |
| azonenberg | One objective, custom-made tube | 23:49 |
| azonenberg | then a camera on the top | 23:49 |
| azonenberg | You need two of them | 23:49 |
| Sync_ | they are not too expensive even new | 23:49 |
| azonenberg | to see two sets of alignment marks at once | 23:49 |
| azonenberg | otherwise you wont get the theta right | 23:49 |
| glowplug | Right. One comes into focus you take a snapshot then bring the other into focus. | 23:49 |
| azonenberg | One on each side of the wafer | 23:49 |
| azonenberg | you align it approximately by naked eye | 23:49 |
| azonenberg | to get it into the FOV of the microscope | 23:50 |
| azonenberg | then tweak the stage to line it up exactly | 23:50 |
| glowplug | Two cameras you mean? And one scope? | 23:50 |
| azonenberg | you'd use a split-field view on the computer | 23:50 |
| azonenberg | No | 23:50 |
| azonenberg | Two objectives, two cameras | 23:50 |
| azonenberg | an inch or so apart | 23:50 |
| glowplug | I've seen a single scope/camera configuration. | 23:50 |
| azonenberg | That is... not nearly as good | 23:50 |
| glowplug | You focus onto one marker then snapshot it. | 23:50 |
| azonenberg | http://www.epakelectronics.com/Images/abm_images/abm_mask_aligner_ma1.jpg | 23:50 |
| glowplug | Then switch focus to the other. | 23:50 |
| azonenberg | This is the setup i'm talking about | 23:50 |
| azonenberg | Two vertical camera/microscopes on the right | 23:51 |
| azonenberg | UV exposure system at the left | 23:51 |
| azonenberg | chuck at the middle | 23:51 |
| azonenberg | you slide one or the other into the central slot to use it | 23:51 |
| azonenberg | the mask stays in one spot | 23:51 |
| azonenberg | and the wafer doesnt move except for tiny alignment corrections | 23:51 |
| azonenberg | needless to say that process is UV sensitive | 23:52 |
| azonenberg | so you want say red or yellow LED illumination | 23:52 |
| glowplug | How many watts for the entire grid? | 23:52 |
| glowplug | That design is actually quite good. | 23:52 |
| Sync_ | not much | 23:52 |
| azonenberg | for the microscope illumination? One or two LEDs each is enough | 23:52 |
| azonenberg | for the main exposure assembly i'd use party-style blacklight fluorescent lamps | 23:53 |
| azonenberg | maybe six or eight of them side by side | 23:53 |
| azonenberg | less if only doing 2" wafers | 23:53 |
| azonenberg | Professional shops use kW-range mercury vapor lamps for like 5-sec exposures | 23:53 |
| Sync_ | hm cut open mercury arc lamp | 23:53 |
| Sync_ | with a shutter | 23:53 |
| azonenberg | but if you use a 20W lamp and it takes a minute orso | 23:53 |
| azonenberg | big deal | 23:53 |
| Sync_ | that'd be easy to do | 23:53 |
| azonenberg | you're not mass producing here | 23:53 |
| azonenberg | Sync_: remember this isnt DUV resist | 23:54 |
| glowplug | Wouldnt you just do what the growers do and find the wavelength mix needed and get LED's for those wavelengths only? | 23:54 |
| azonenberg | its 405nm or so | 23:54 |
| Sync_ | yeah but the lamp will still do | 23:54 |
| glowplug | Ahh I see | 23:54 |
| azonenberg | glowplug: http://www.blacklight.com/items/CHUSF20BLB | 23:54 |
| glowplug | I have 3w violet LED's | 23:54 |
| azonenberg | Something like that | 23:54 |
| azonenberg | Fluorescents will probably be a lot cheaper | 23:54 |
| glowplug | They probably produce more usable power in that wavelength than the blacklights. | 23:54 |
| glowplug | I got them for only $12 each. | 23:55 |
| azonenberg | Hmm | 23:55 |
| glowplug | They are probably cheaper now. | 23:55 |
| azonenberg | Just make sure you diffuse them well | 23:55 |
| Sync_ | yeah | 23:55 |
| azonenberg | or you get some spots unevenly exposed | 23:55 |
| glowplug | Good point. | 23:55 |
| Sync_ | I wonder when uv lets show up that actually last a while | 23:55 |
| glowplug | So there are no software tricks to get that aparatus down to 1 scope? | 23:55 |
| Sync_ | not with annoying mechanical effort | 23:56 |
| glowplug | The scope outputs are superimposed? Stereovision? Or seperate screens? | 23:56 |
| Sync_ | just two screens | 23:56 |
| azonenberg | glowplug: http://www.cleanroom.byu.edu/alignment.phtml | 23:57 |
| glowplug | I see. Page 3 explains what I was missing. | 23:58 |
| glowplug | I've seen this proces before. But I forgot that you are aligning 4 total markers. Two on the aparatus and two on the sample. | 23:58 |
| azonenberg | Yep | 23:59 |
| glowplug | That would be a massive pain with only 1 scope. =( | 23:59 |
| azonenberg | Yeah | 23:59 |
| azonenberg | Possible, but you really dont want to | 23:59 |
| azonenberg | spend the extra $200 or whatever on the second scope | 23:59 |
| azonenberg | Two webcams, two tubes, two objectives | 23:59 |
| --- Wed Mar 20 2013 | 00:00 | |
Generated by irclog2html.py 2.9.2 by Marius Gedminas - find it at mg.pov.lt!
