#homecmos IRC log for Saturday, 2011-10-15

azonenbergSo... current priorities04:30
azonenbergbuilding process control modules04:31
azonenbergfor BGA reflow (unrelated project) and my spin coater04:31
azonenbergAs well as probe tip etching04:31
azonenbergI want to think if its possible to combine them all onto a single generic "industrial control module"04:31
azonenbergwith a unified API so i can tlak to them all with similar code04:31
B0101Hi Azonenberg06:22
azonenbergAny progress?06:22
B0101I was sick06:22
B0101didn't do any experiments06:22
azonenbergA legitimate excuse lol06:22
azonenbergBtw, look up the paper "Etch rates for micromachining processes, part II"06:23
azonenbergActually, why dont you set up a wiki page for "recommended reading"06:23
azonenbergthat paper is not one that you will read once and go "oh, cool idea"06:23
azonenbergits mostly tables of numbers06:23
azonenbergand discussion of results06:23
azonenbergEdtremely useful reference06:23
azonenbergthe de facto "etch bible"06:23
azonenbergcovers both wet and plasma on like 90 different materials06:24
azonenbergI have both a PDF and a hard copy, the hard copy is pinned up to my bulletin board above my desk06:25
azonenbergi use it all the time06:25
azonenbergother good references - "Tantalum oxide thin films as protective coatings for sensors" if you're using Ta2O506:28
azonenberg"Fabrication of very smooth walls and bottoms of silicon microchannels for heat dissipation of semiconductor devices" for KOH etching06:28
azonenberg"Reproducible Electrochemical Etching of Tungsten Probe Tips" for making microprobes06:28
CIA-67homecmos r145 | wiki/Recommendedreading.wiki | Created wiki page through web user interface.06:31
B0101Gimme a few links to put up on the new page06:32
azonenbergThose papers are very useful06:33
azonenberglet me try to find donwload links that are public06:33
azonenbergsilly subscriptions06:33
azonenberg"Etch rates for micromachining processing, part II" http://microlab.berkeley.edu/labmanual/chap1/JMEMSEtchRates2(2003).pdf06:33
azonenberg255 citations06:33
azonenberg"Tantalum oxide thin films as protective coatings for sensors", http://orbit.dtu.dk/getResource?recordId=266688&objectId=1&versionId=106:34
azonenberg"Fabrication of very smooth walls and bottoms of silicon microchannels for heat dissipation of semiconductor devices" - http://linkinghub.elsevier.com/retrieve/pii/S002626920000015X06:36
azonenbergunfortunately that isnt a public link06:36
azonenberg"Reproducible Electrochemical Etching of Tungsten Probe Tips", https://apmc.zyvex.com/literature/apmc-literature-surveys/stm-tip-fabrication/stm-tip-review/Reproducible%20Electrochemical%20Etching%20of%20Tungsten%20Probe%20Tips.pdf06:36
CIA-67homecmos r146 | wiki/Recommendedreading.wiki | Edited wiki page Recommendedreading through web user interface.06:39
B0101sorry, i gtg, see you tommorrow06:40
bart416azonenberg, I might be able to get my hands on one of these: http://www.tequipment.net/LecroyWaveJet352.html07:16
azonenberg500 MHz?07:17
bart416Main issue is logistics07:19
bart416I can't go and pick it up myself07:19
bart416Too long of a distance07:19
bart416So might have to pass on it07:19
bart416But 150 euro for that thing...07:19
azonenbergUsed, i assume?07:19
azonenbergAnd o_O07:19
azonenbergi have no idea what that is in USD but its cheap :p07:20
bart416Used, but in good condition07:20
bart416Roughly 200 USD07:20
azonenbergi paid close to 1K USD for mine07:20
bart416Normally you'd pay over a tenfold of that for a new one07:20
azonenbergAnd that looks way better per channel07:20
azonenbergMine has the 16ch LA which is nice, but deep memory would help greatly07:20
azonenbergfor some applications07:21
bart416Well, logic analyzer you can build07:33
bart416Scope is a lot harder07:33
bart416An FPGA, USB chip, and some buffers and you have a LA07:33
azonenbergI plan to do that soon actually07:36
azonenbergmake one with really deep memory07:36
bart416Heh, I got to play with one of those newer NAs this week07:36
azonenbergWhy do cheap scopes not have deep memory?07:38
azonenbergits not like ddr2 is expensive07:38
azonenbergyou could throw a hundred megabytes on there for $1007:38
bart416most scopes use static ram as far as I know though azonenberg08:34
bart416well at least all the ones I've had to open up do so08:34
swkhanazonenberg_work: still no wafer. what did dhl/fedex say?23:02
azonenbergswkhan: it was us post office23:03
azonenbergand they say it was signed for23:03
azonenbergand delivered23:03
azonenbergyou're saying it got lost? :(23:03
swkhanoh! okay, i'll check at the post office on monday then23:03
azonenbergyou have the tracking #, right?23:03
swkhani don't remember it. can you pm it to me?23:04
swkhanthey said it was delivered ~1 week ago?!23:06
azonenbergSo somebody has it, apparnetly lol23:07
swkhanthey did make a mistake recently. they gave us some highly flammable substance that "donna ...?" owns23:11
swkhansomething dodecaethylthiol or something23:11
swkhanwe haven't tried to contact donna because we're apathetic / lazy i guess =\23:11
swkhando you have much experience with a semiconductor parameter analyzer?23:17
azonenbergwhats that? :P23:17
swkhanor a 4 point probe even?23:17
azonenbergI know the idea of a 4-point probe but i havent used thm23:17
swkhanit's a really fancy set of voltage sources and current sources and voltage monitors and current monitors23:17
azonenbergMy sheet resistance measurements to date have been no more sophisticated than "is there something conductive on top of this insulating film or not?23:18
swkhanall i really need is an easy way to probe a really small metal insulator metal capacitor23:18
swkhanso i have it like a crossbar +23:18
azonenbergSo you have two layers of metal with dielectric between them23:19
azonenbergDefine small23:19
azonenberg50nm? 200um?23:19
swkhanlarger =p23:19
swkhanlike maybe 500 um to 1 mm23:19
azonenbergthats like, hand solderable23:19
swkhannot with my hands :\23:19
azonenbergWhat do the pads look like?23:19
swkhani don't have bond pads23:19
azonenberghow do you connect to the layers?23:19
azonenbergYou dont have bond pads23:20
azonenbergso for the top layer you just probe the metal23:20
swkhanyou type faster than i think23:20
azonenbergIs the bottom layer bigger?23:20
swkhanwell they are at like a T junction23:20
azonenbergSo you have two metal bars crossing at a T23:20
swkhanso i have the bottom electrode shadow mask patterned horizontally23:20
azonenbergthe capacitor is where they overlap23:20
azonenbergAnd the 0.5mm figure is what exactly?23:21
azonenbergthe width of one bar?23:21
swkhanthe planar distance from where the bottom electrode is probed to where the top electrode is probed23:21
azonenbergSo standard multimeter probes are a little big23:22
azonenbergYou dont have proper micropositioners i take it?23:22
azonenbergIf you did this'd be a solved problem23:22
swkhanwe have some sort of positioners but either they don't work perfectly or i stink at using them or both23:22
swkhanwe have tungsten probe tips that say 45 degree angle and 12 um which i assume is the tip width23:23
swkhanor tip radius or tip diameter23:23
azonenberg12um is plenty for this size23:23
azonenbergi've done large IC components with 25um probes23:23
swkhanwell smaller is better. 0.5 mm is pathetic23:23
swkhanbut more important than all of that is some reproducible measurement23:23
azonenbergwell I've hit 20um targets with homebrewed submicron probes23:24
swkhanthe manipulators kind of bobble a bit when i lower or raise them23:24
azonenbergand cheap micromanipulator 110 positioners23:24
swkhan110 dollars?23:24
azonenbergno, thats the model number23:24
azonenberg110 and 21023:24
azonenbergThey were around $100 each on ebay though lol23:24
swkhanbecause ours were about 1000 each23:24
swkhanmaybe 10023:24
azonenbergThe $1K ones are overkill23:24
swkhani just remember they weren't worth whatever we paid for them23:24
azonenbergmost of them are good to submicron23:24
azonenbergThis is me hitting a bond pad on a 350nm 3-metal microcontroller (PIC12F683)23:25
azonenbergwith a homemade submicron tungsten tip23:25
swkhanwow =)23:25
azonenbergmagnification is in the 60-120x range23:25
swkhangrr i'm really frustrated23:25
azonenberghttp://colossus.cs.rpi.edu/pictures/2011/June/6-24-2011%20-%20lab/S7300935.JPG is the rig i have23:25
azonenbergi assume yours is similiar?23:25
swkhani thought i had a good research idea and i'm being derailed by equipment23:25
azonenbergI got a fiber optic illuminator since taking this pic, huge help :P23:26
swkhanours is way uglier, smaller, and way less incapable23:26
azonenbergLol, my probing station was bought used on ebay23:26
azonenbergYou're saying your gear isnt as nice?23:26
swkhanwell, i'm more irritated that the girl who set this up is totally incompetent23:27
Action: azonenberg wonders at the feasibility of making capacitors on his process now23:27
swkhanand told me that she knew this machine worked23:27
swkhani'm going to get scooped23:27
swkhani just want one paper, then i can be happy again23:27
azonenberg20um capacitors made of evaporated copper on Ta2O5 high-K dielectric23:27
azonenbergmaybe 50 for starters23:27
azonenbergi think are entirely feasible23:28
azonenbergAnd my probe tips were made in this apparatus http://colossus.cs.rpi.edu/pictures/2011/June/6-22-2011%20-%20lab%20work/S7300912.JPG23:28
azonenbergstandard electrolytic etching23:28
azonenbergseen closer, http://colossus.cs.rpi.edu/~azonenberg/images/homecmos/2011-07-05/probe1/probe1_008.jpg23:29
swkhanwell how thick should a bond pad be by the way? how thick would your metal electrode (copper) be?23:29
azonenbergHmm, depends on the bonding process23:29
azonenbergWith copper its more annoying since you need a barrier layer23:29
azonenbergand adhesion23:29
swkhani made mine ~100 nm each for top and electrode23:29
azonenberg100nm is fine if you are probing23:29
azonenbergi think23:30
swkhani had an adhesion layer too23:30
azonenbergTa? Cr?23:30
azonenbergYeha, Cr is the de facto standard23:30
azonenbergthats what i use too23:30
azonenbergthough i hear sputtered Ta is catching on23:30
swkhanbut it takes forever to sputter all this stuff23:30
swkhani was just talking to a professor about this yesterday =)23:30
azonenbergI do evaporation, a nice thick film only takes a few minutes once you have decent vacuum23:30
swkhani was reading a book on electrodeposition23:30
swkhanand they said that nb and v give better adhesion layers than cr or ti23:31
azonenbergAnd like i said, thickness depends on the proces23:31
azonenbergfor example if you are soldering to it (flip chip bonding) you want a micron ish23:31
azonenbergor it'll just dissolve into the solder23:31
azonenbergand yes, i've read a little about Nb and V23:31
azonenbergBut they're pretty exotic23:31
azonenbergand not used because while they may be better, its not by much23:31
swkhanchromium can form quadruple bonds23:32
swkhanmy mind is still blown23:32
swkhani need to relax23:32
azonenbergThats why it sticks so well23:33
azonenbergand i have homework to do but i dont want to :(23:33
swkhani'm going to a film festival with some friends. i need to take my mind off research that doesn't work23:33
azonenbergI think i'm going to try one of my alternative hardmasking ideas23:33
swkhani'd invite you, but you'd have to take a plane... =p23:33
azonenbergOne that i came up with a long time ago but never tried23:33
azonenbergi even have the coated wafer, just need to actually etch23:33
azonenbergand lol23:34
azonenbergYeah, kinda on the wrong side of the continent :p23:34
swkhanthe chromium mask?23:34
azonenbergThe Cr mask has to wait until i get up to campus next week to do the thick Cr film23:34
azonenbergThis one is older but i never actually tested23:34
azonenbergTa2O5 plus Cu:Cr stack23:34
azonenberguse the metal as a mask for HF etch of the oxide23:34
azonenbergthen use the oxide as a mask for KOH of the silicon23:34
azonenbergi have the three-film wafer sitting on a shelf but never actualy did anythign with it23:35
swkhani'll talk to you later azonenberg. i'm going to ask my professor if he knows what happens to the wafer as well. i'll double check the office before i go23:36
swkhanhonestly, if i don't find it in a week, i'm just going to use one our spares and thermally grow the oxide in atmosphere23:36
azonenbergLol that works23:36
swkhanbye azonenberg =)23:37
--- Sun Oct 16 201100:00

Generated by irclog2html.py 2.9.2 by Marius Gedminas - find it at mg.pov.lt!