#homecmos IRC log for Saturday, 2012-04-28

--- Sat Apr 28 201200:00
B0101hello azonenberg03:58
azonenbergbeen so busy lately lol... i want to finish my v2 spin coater soon03:59
azonenbergi just got a nice microscope too03:59
azonenbergnicer than the last one03:59
azonenbergand i want to try litho on it03:59
B0101oh cool! any pictures of your new microscope?03:59
azonenbergits a mix of olympus BH and BH2 series parts (BH body and BH2 head)04:01
azonenbergthe stage has a 4" wafer cutout in it04:02
azonenbergi've been meaning to do a nice comparison between the two but havent had time04:03
azonenbergthis is a single shot taken with the new scope http://colossus.cs.rpi.edu/~azonenberg/downloads/40x_annotated.jpg04:03
azonenbergi hadn't finished adjusting the illuminator so you can see it's dark on top, that got fixed since then04:03
azonenbergneedless to say the chip isn't one of my own design :p04:03
azonenbergthough the 1-micron 2-metal process tech is pretty close to what i migth be able to do in a couple of years :p04:04
azonenbergoh, and it has both brightfield and darkfield imaging capability :D04:05
azonenbergno NIC though04:06
azonenbergi'd like that eventually04:06
azonenbergbut all the optics are $$04:06
azonenbergso next on my todo list is to get some nice sodium-free quartz glassware for doing RCA cleans in04:07
azonenbergthen buy an oxidation furnace04:07
B0101wow, that going to be a lot of stuff you will have in your lab.04:07
azonenbergI'm going to post photos of the gear again soon04:08
azonenberggot a lot of new upgrades04:08
azonenbergdo you follow my blog? I've been starting to do interesting stuff there04:08
azonenbergnot necessarily fab related04:08
B0101i will see, (very slow connection here at library)04:10
azonenbergGoing to do a series of posts on my lab in the near future04:11
azonenbergthen gradually update as i get new gear04:11
B0101hmm, pcb fab screwups? interesting04:12
azonenbergYeah, they totally borked my soldermask04:12
azonenbergi got a replacement board free04:14
azonenbergso it was all good04:14
azonenbergit was actually a result of their panelization script and a bug in my gerber not playing well04:14
azonenbergi had a vertex outside the board perimeter04:14
azonenberginstead of clamping to the perimeter they deleted the entire polygon04:14
azonenbergthe copper plane was wrecked too04:15
azonenbergThis is my new board/firmware design lab/office btw :) http://i.imgur.com/wGemc.jpg04:15
azonenbergthe netbook and tablet were just there to charge and i turned them on for show, they're not part of the usual combo04:17
azonenbergbut the four big screens i use all the time, WAY more productive that way than one or two04:17
B0101and i heard about H2SO4 + H3PO4 being a good semiconductor etchant. I am going to test it out04:19
azonenbergHmm, interesting04:19
azonenbergfor silicon??04:19
azonenbergwonder how it works04:19
azonenbergi suspect it might be like HNO3+HF04:19
azonenbergSi -> SiO2 -> something soluble04:19
azonenbergIt's isotropic, right?04:20
azonenbergnot sensitive to crystal orientation like NaOH is?04:20
azonenbergor KOH04:20
B0101well, i cannot answer these questions now untill i do a few tests, but according to some chemists, it is isotropic04:21
B0101for silicon, do you use nitric acid along with HF?04:27
azonenbergi havent done much Si etching yet, what i have was using KOH with a metal or oxide hardmask04:27
azonenbergi wasnt trying to be cmos compatible yet04:27
B0101now, for some reason, all my lab glassware never survive a week in my lab04:30
azonenbergi havent broken any glassware in months04:34
B0101its always either me or my labmates who break them, well, its a waste04:37
azonenbergyeah lol04:37
azonenbergI need to get some nice quartz04:37
azonenbergall of my current stuff is pyrex04:37
azonenbergso not cmos safe04:37
berndjpyrex isn't cmos-safe? what happens?05:03
azonenbergberndj: i just heard that from stanford05:04
azonenbergapparently pyrex contains enough sodium silicate05:04
berndjyeah, it does05:05
azonenbergthat in some critical processes (perhaps not all of them)05:05
berndji guess the sodium leaches out?05:05
azonenbergyou get Na+ contamination05:05
azonenbergSo it doesnt matter that i used KOH in all of my glassware (or most of it) anyway ;p05:05
azonenbergit wasnt cmos compatible to begin with05:05
azonenbergso the plan is, buy a couple of pyrex beakers05:05
azonenbergkeep them in clean storage and only use them for RCA cleans05:05
azonenbergonly clean with distilled water, etc05:06
azonenbergthen get a furnac05:06
Last message repeated 1 time(s).05:06
azonenbergand fool around with thermal oxidation05:06
berndji wonder if there's a market for rentable cleanroom space05:07
azonenbergLol no idea05:07
berndjhard disk data recovery services could use some i guess?05:07
azonenbergmy school rents out time in their cleanroom, i know that much05:07
azonenbergand actually, funny story05:07
azonenbergi know a guy (former enginer at IBM now going for a grad degree here)05:08
azonenbergwho had a bad hdd motor that wouldn't spin up sometimes05:08
berndjwhat sort of customers do they have (as cleanroom landlords)?05:08
azonenbergso he went into the cleanroom05:08
azonenbergopened it up05:08
azonenbergand tapped the rim of the platter with a gloved finger until it started spinning05:08
azonenbergthen copied his data off :p05:08
azonenbergre customers, no idea05:08
azonenbergapparently they dont get much05:08
azonenbergi used a few hours on the SEM doing failure analysis for a MEMS group once05:08
azonenbergbut i think most of their users are internal05:09
berndjlol. when i was a kid we had a 40MB disk (WOW! so HUGE!) that would suffer from stiction; we'd regularly have to open up the case and manually "unstick" the disk05:09
berndjgiving it a sharp twist by hand05:09
azonenbergwell what i find funny is that he just casually walked into the cleanroom05:09
azonenbergand did data recovery himself05:09
berndji guess you get spoiled when you have access to labs05:10
berndji can imagine chemists warming their sandwiches over a bunsen burner05:10
azonenbergwell i'm used to having a small but well-equpped lab and am trying to expand05:11
azonenbergdid you see the pic i posted of my firmware/CAD work area earlier?05:11
berndjjust how clean does a data recovery cleanroom need to be?05:11
berndjboxes with lots of intractible-looking red lines?05:11
azonenbergprobably class 1000 is plenty (ours is 100)05:11
azonenbergyou only need to avoid particulates on the surface of the platter that are big enough to crash into the read-write head05:11
azonenbergor obstruct data reads05:12
berndjyeah, and you only need the particles to stay off long enough to get the data off05:12
azonenbergthe class 100 we have is probaly enough to build drives in lol05:12
azonenbergand no, the pic was this http://i.imgur.com/wGemc.jpg05:12
berndjwhee, nice layout pr0n05:12
azonenbergLol, wanna see the full res?05:13
berndjcute dino05:14
azonenbergOh, my monitor lizard? pun intended05:14
berndjoh a lizard, i thought it was a dinosaur05:15
azonenbergit is a dinosaur05:15
azonenbergbut i didnt have any komodo dragons handy05:15
berndji really need to stop dreaming about layout pr0n like that and just build a dumb audio amp or something05:15
azonenbergand i wanted a monitor lizard05:15
azonenbergthat board is an FPGA based single-board computer05:15
azonenbergtook most of a month to design05:15
azonenbergi'm now waiting for the board to arrive in the mail, should be here any day now05:16
azonenbergspartan6 XC6SLX25, 128MB nand flash, 64MB DDR SDRAM, 10/100 ethernet, four push buttons, eight LEDs, two high-speed ribbon headers with 8x 1 Gbps LVDS pairs on them plus a few single-ended IOs05:17
azonenbergmy biggest design yet by about a factor of two or three05:17
berndji have mixed feelings about this brave new world where a whole board is dominated by a "mecca" with 1000 pins05:22
berndjOT1H it's very impressive, but OTOH it makes the world a more magical (as in, inscrutable) place05:23
azonenbergwell i'm writing the firmware for the fpga :p05:23
berndjcan't we just go back to using discrete transistors?05:24
azonenbergso i know down to the netlist level exactly whats happening05:24
berndjyeah, i know, YOU as the creator know how it works, but if you find a random board lying next to the railroad, you can infer almost nothing about it05:24
azonenbergOh, i can infer quite a bit05:24
azonenbergever seen an FPGA naked before?05:24
azonenbergfrom my friend's weekly centerfold blog05:25
berndjactually, i don't think i've ever knowingly seen an fpga at all05:25
berndjcmosfold is in my reader :)05:25
azonenbergyou should check that blog out lol05:25
azonenbergi think he might have gotten a little carried away with the whole silicon pr0n thing05:26
berndjhow do you check a layout of that complexity? do you check it, or do you just trust the netlist + layout program?05:26
azonenberghe has nude photo shoots every week these days :p05:26
azonenbergand lol05:26
azonenbergnormally for FPGAs i write the code in Verilog05:26
azonenbergand unit test the heck out of it05:26
azonenbergtest driven development is the way to go for a big system05:27
azonenbergwrite test cases based on what the system should do05:27
azonenbergcode until they pass05:27
azonenbergwrite more tests to check for every conceivable corner case05:27
azonenbergfix the bugs you find05:27
azonenbergrepeat until you can't make it break :p05:27
berndjand the layout itself?05:28
berndji mean that you haven't accidentally wired Vcc to the ground plane05:28
azonenbergoh, you mean the pcb05:29
azonenbergor the HDL?05:29
azonenbergi use very differnet strategies for board vs logic design05:29
--- Sun Apr 29 201200:00

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