<azonenberg>
1/8" PVC from Mcmaster-Carr, held together with L-brackets
<azonenberg>
1/8" clear acrylic on the sash
<azonenberg>
240cfm duct fan
<azonenberg>
whcih on the 1x2 foot opening gives 120 linear FPM, minus a bit for the cracks (joints arent caulked etc) and you get 80-100
<azonenberg>
well within the safe range
<azonenberg>
i tested with IPA and acetone and it kept concentrations well below the odor threshold at all times
<azonenberg>
whcih, depending on who you ask, is 40-100 PPM for acetone and the safe exposure limit is 500-1000 depending on the regulators you ask
<azonenberg>
So i'm well within safe limits
<azonenberg>
IOW, the thing actually works
<soul-d>
nice had 500m3 somthing fan deliverd today :P probably overkill for that ;)
<soul-d>
i take those numbers are from woerking area
<azonenberg>
You actually dont want too high or you get fortices
<soul-d>
egg 8 hour work day ?
<azonenberg>
vortices*
<azonenberg>
which have a habit of leaking nasties out of the hood on the edges
<azonenberg>
hecne the 120fpm cap
<azonenberg>
and yes, the PEL i quoted was 8-hour time weighted
<azonenberg>
the MSDS listed three limits depending on agency but they were all 500-1000 PPM range for acetone
<azonenberg>
iirc all of the chemicals i work with except HF have the PEL significantly above the odor threshold
<azonenberg>
Meaning if you cant smell it, its safe
<azonenberg>
I wanted to test first with relatively safe substances like IPA
<azonenberg>
The next test will use something stronger like concentrated HCl
<azonenberg>
if i cant smell that at all from outside the hood i'm good :)
<azonenberg>
Odor threshold 0.25 to 10 PPM
<azonenberg>
personally i think the 10 is high, that stuff is pretty potent
<soul-d>
donno if i smelled that before id probably try to convert some amonia fertilizer to KNO3 since ive done that before
<azonenberg>
Concentrated hydrochloric acid is not something you are going to forget the smell of lol
<soul-d>
but then again chemistry is on hold still
<soul-d>
only have 30% and 10%
<soul-d>
but never opened the 30% yet
<azonenberg>
Mine is 32% i think
<azonenberg>
And do so with caution
<azonenberg>
It will most likely fume strongly
<soul-d>
it's 5 liters to :P havent touched it since i bought i lol donno even why :D
<azonenberg>
Five liters??
<azonenberg>
Mine is a 1L bottle and i thought that was a lot
<soul-d>
stron concetrations only came in this package
<azonenberg>
i had trouble buying any less except in very high purity
<soul-d>
lol ?
<azonenberg>
not as in concentration
<azonenberg>
but like ACS reagent grade or trace metals basis
<azonenberg>
you can get in half-liter bottles
<azonenberg>
Technical grade the smallest i could get was 1L
<soul-d>
i had trouble finding it :)
<azonenberg>
where are you located again?
<soul-d>
oh still is wall cleaning grade
<soul-d>
netherlands
<azonenberg>
Well it's technical, but pretty high grade
<azonenberg>
as far as technical goes
<azonenberg>
I intend to buy some ACS grade when this runs out
<azonenberg>
but it's lasting me forever
<azonenberg>
just doing PCB etching etc with it
<soul-d>
still use ferric chloride for that
<azonenberg>
i use one part conc HCl to 6 parts 3% H2O2
<azonenberg>
gently heated
<azonenberg>
it's stronger and also transparent
<azonenberg>
so you can watch the board etch
<soul-d>
probably be easyer to follow along true but i assumed that stuff was bit more nasty then this brown stuff
<azonenberg>
You do need better ventilation
<azonenberg>
But if you have it, the etch quality is superior
<azonenberg>
it also doesnt get rust stains on your glassware
<azonenberg>
cleans off nicely, all of the waste products are water soluble
<soul-d>
also have the sodium perchlorate stuff for etching somewhere
<azonenberg>
persulfate you mean?
<azonenberg>
perchlorate would probably blow up, not etch :p
<soul-d>
yes that srry :)
<azonenberg>
And when i'm done etching i just store the CuxClx contaminated waste in a jar until the next scheduled hazmat pickup
<azonenberg>
the county has one or two a year
<soul-d>
we do have a disposal thingy for chemicals
<azonenberg>
Yeah, I'm trying to run my lab as by-the-book as I can
<azonenberg>
even if the volumes involved probably arent large enough to matter
<azonenberg>
rather not take chances
<azonenberg>
And its a good habit to get into
<azonenberg>
for if i end up working in a commercial lab or handling larger volumes of stuff
<soul-d>
yeah thats why i stopped until reasonable buget/safe enviroment since im pretty clueless
<soul-d>
problem is hard to do self study
<azonenberg>
I figured an open window was probably good enough for what i was doing, not handling anything too nasty
<azonenberg>
But better engineering controls never hurt
<azonenberg>
So i decided to build the hood
<azonenberg>
Next step is going to be to use the aluminum stock i just ordered to machine a little jig
<azonenberg>
to hold my wafer over the evaporator basket so i can do nickel deposition
<azonenberg>
it sublimes so i cant use the tool's normal under-basket moun
<azonenberg>
which expects a material that melts before evaporating
<azonenberg>
At that point i'll be good to go for through-wafer etch testing
<azonenberg>
In parallel i have some ideas for improving lithography resolution
<azonenberg>
theoretically down to 330nm
<azonenberg>
but realistically i think 500-750 will be a limit with my optics
<soul-d>
you where at 22um now ?
<azonenberg>
It was nominally the 20um node but i think the exact half-pitch was 21 and change
<azonenberg>
generally overetch meant features were a little smaller than that and spaces a little larger
<azonenberg>
This is doing 10x reduction of a 200um mask
<azonenberg>
I'm going to buy 12.5um masks from a real mask shop
<azonenberg>
then try 4/10/40x reduction of them as well as contact printing
<azonenberg>
I dont know if i can project 12.5um features so i'm going to put some larger features on the mask too
<azonenberg>
probably 25 and 50
<azonenberg>
i'm quite certain i can resolve 50 on the mask, times 10x reduction is 5um
<azonenberg>
so i can hit that as a minimum
<azonenberg>
but if i use the 40x objective (which has proven flaky in the past) i could potentially go 12.5um / 40x = ~330nm
<azonenberg>
again thats a theoretical number and i think 500-750 will be a practical limit
<azonenberg>
But submicron would be very nice
<soul-d>
true, spend bit to much on electronics so most projects came to grinding halt also since pc is getting old and buggy don't want to code to much on it
<soul-d>
mostly scavenging stuff that could be used
<soul-d>
was even looking back at amature telescope making for fun want to do some mirrors myself
<azonenberg>
Well, if you decide to build an evaporation or sputtering rig
<azonenberg>
let me know lol
<azonenberg>
we can collaborate on design
<soul-d>
long way to go still but shall see what 2012 will bring i do want to build more stuff
<soul-d>
both of those where with a vacume right only idea i had for evap is a basic high temp oven schematic 40 years old :P carbon rods and lots of power
<soul-d>
but i want allot like a ballanced buget book, get piece of community land to grow own food budget for rehabilitation need to gain lots of (healty ) weight
<soul-d>
anything that is left over is for learning purposes and projects :)
<azonenberg>
No, for evap there's a bit more involved
<azonenberg>
You want to use a tungsten filament coiled into a basket
<azonenberg>
You can buy them from Ted Pella among other vendors
<azonenberg>
Put pellets or wire of your material inside it
<azonenberg>
Then pump the chamber down to the 1E-6 torr range
<azonenberg>
and run current trough the filament
<azonenberg>
Generally speaking you'll want a couple of volts at pretty high current
<azonenberg>
tens to hundreds of amps
<azonenberg>
general control method is a variac off of wall power to control voltage, followed by a step-down transformer
<soul-d>
k yeah still have my eyes out on vacume sture thats probably the hardest part to get right
<azonenberg>
a large enough bell jar will cost $$, yes
<azonenberg>
then you'd need a roughing pump and a high-vac pump, probably a diffusion pump
<azonenberg>
you cant get deep enough to evaporate with only a mechanical pump
<soul-d>
2 stage or somthing i thought you said ?
<azonenberg>
I have a 2-stage mechanical pupm but that only hits 4E-2 torr
<azonenberg>
you have to be able to hit the -6 range which means a diffusion or turbopump
<azonenberg>
the second are very expensive so for hobbyists it basically means you need a diffusion
<azonenberg>
Sputtering uses much less deep vacuum, you can hit that with a mechanical pump
<azonenberg>
But you need a source of inert gas (usually argon) and high voltage
<azonenberg>
So it poses its own set of problems
<soul-d>
high voltage is easy depending of current
<soul-d>
got 5 kv transformers :P
<azonenberg>
Depends on what you're sputtering, even 500 - 1kV might be enough
<azonenberg>
But you need tens to low hundreds of watts
<azonenberg>
to power the plasma
<azonenberg>
This assumes DC sputtering, not RF
<azonenberg>
also, if you are doing a deposition of more than a small amount of material you need to cool the target
<azonenberg>
so it wont metl
<azonenberg>
melt*
<azonenberg>
small meaning <50nm probably
<soul-d>
my kv transformers are 400watts
<soul-d>
3-4,5 kv
<azonenberg>
You might not want that much voltage depending on the material, i am more familiar with the basics of the process and not specific parameters so i could be wrong
<soul-d>
but thats for lighting L(
<azonenberg>
But the operating principle is similar to that of a neon sign
<azonenberg>
you strike a plasma through low-pressure inert gas
<azonenberg>
in fact, the plasma will glow very much like a neon sign
<soul-d>
tb
<soul-d>
there are plasma light's there day's
<soul-d>
but expensive to steal the transformer from
<azonenberg>
Lol
<azonenberg>
The only difference is that you tune the parameters for removing of material from the target (and depositing on your sample) and not for maximum brightness
<soul-d>
but will be along way before i start playing with high voltage though :) light bulb is bit easyers then above :P
<azonenberg>
Yeah, i dont trust my HV skills yet
<soul-d>
but this high rating tranformers start at 70watt
<soul-d>
for lights
<azonenberg>
i want to start slow and make sure i'm not going to electrocute myself :p
<soul-d>
hps and mh
<soul-d>
hpresure sodium and metalic halide or somthing
<azonenberg>
i see
<soul-d>
and 2 kinds electrincs ones i think done by som swithcing stuff or simple bloks of copper types ( like for TL but but bigger )
<soul-d>
maybe look at what type of componets they use in electric types
<azonenberg>
I'm not too familiar with HV in general so i cant say
<soul-d>
me neither just hook up the light to grow peppers under it :P
<soul-d>
and glad i don't get shocked bu the system lol
<soul-d>
but still turn on all high voltage stuff on from a distance
<azonenberg>
Lol, yeah
<azonenberg>
Good practice
<soul-d>
yeah ever since i had to quickly try laserprinter 's stepper motor and plugged it in wrong way around chips do bang loud :)
<soul-d>
on the printers main board *
<azonenberg>
lol
<soul-d>
but i should make a picture of my shed :P
<soul-d>
you probably call it chemical hazard lol
<azonenberg>
lol
<soul-d>
now pots and pan's with kno3 and sugar to :) as smoke stuff to play around on new year a bit don't have a ball mill otherwise would made some candles
<azonenberg>
lol, ok thats pretty bad compared to my setup :p
<soul-d>
lol no it's worse
<soul-d>
maybe ill blur an image :P
<soul-d>
oh on picture it looks ever worse then in real :P
<soul-d>
but it will show you why im waiting on buget to fix the shed :P
<soul-d>
most of it is junk anyhow :P need to bring it away some day
<soul-d>
now ofcourse you where wondering what the oven is for :P
<soul-d>
i used that to heat kno3 and sugar :P
<azonenberg>
lol, ok
<azonenberg>
yeah, my place looks nowhere near that bad
<azonenberg>
i'm trying hard to make sure i'm as by-the-book as possible
<soul-d>
usaly before i do somthing i first need half a day to clean
<azonenberg>
lol wow
<soul-d>
if i knew winter was gonna be this hot
<soul-d>
i would have had it clean though
<azonenberg>
I'm actually in the process of tidying up the whole apt, roommates are gone and the semester is over
<azonenberg>
So now i can bring the place up to my usual standards
<azonenberg>
i'll post some pics including all of the new lab equipment once the cleaning is done
<soul-d>
yeah did home partly especialy since bought gazillion electrionics i need to get stuf sorted
<soul-d>
clean sorted work area does work better
<soul-d>
and less stress full
<soul-d>
but i need a reasonable buget
<soul-d>
not gonan fix that with few hunderd bucks
<soul-d>
since its single walled shed you cant realy store much
<soul-d>
metals rust
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<soul-d>
read the vacume pdf for a bit so if i understand that system only reaches the wanted vacume if chilled (probably by liquid nitrogen ) ?
<superkuh>
Yes. You need to cool the zeolite (13x).
<superkuh>
The conductance between the zeolite and main chamber should be as large as possible as well.
<soul-d>
13x stands for some industrie standard form of the zeolite stuff ?
<superkuh>
Yes. If I recall correctly it absorbs nitrogen and oxygen fairly well within the structure. I cannot recall the exact width of the cavities, some tens of nm.
<superkuh>
Er, wrong.
<superkuh>
Sorry. angstroms.
<soul-d>
i saw 8 passing by on google
<soul-d>
k then makes sense why azonenberg looks at sputtering :)
<soul-d>
btw you have glassblowers near you that make chemisty labware on design? cause i actually do have a few around me
<superkuh>
Me? I could probably find one at the state university that's 100m away from where I am sitting. But it's too expensive.
<soul-d>
heh true it would be expensive for custom stuff but this shops build chemistry labware and gassious lighting so they probably could make half sputtering thingy from the store
<azonenberg>
soul-d: A sputtering apparatus would only need a bell jar and a baseplate, both of which can be bought premade
<azonenberg>
the only custom work would be drilling holes in the base plate and inserting high-voltage feedthroughs
<azonenberg>
and sealing appropriately to hold vacuum
<soul-d>
mmm, don't forget im in tiny country only jar bell i found is cheap bottle looking one with no information
<smeding>
love that place though i do not have the money to buy stuff there
<smeding>
or enough interest, really, a lot of the time
<soul-d>
heh
<soul-d>
need some food bbl
<azonenberg>
lol
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<berndj>
is the "snooker ball" model for calculating mean free path sorta sane for estimating the MFP of an electron in a gas?
<azonenberg>
Hmm, maybe? I'm not too familiar with electrostatic interactions
<berndj>
just thinking of how to bootstrap a high vacuum vessel
<berndj>
since apparently welds are really, really hard to make properly gas-tight
<berndj>
but if electrons can get far enough, why not use a big beam of those to suture up the crude weld from the inside?
<azonenberg>
Hmm, no idea
<azonenberg>
Never tried building a pressure vessel
<azonenberg>
always bought them
<berndj>
i'm pretty sure i can't afford one :)
<soul-d>
i thought id download macguyver to inspire me but it was dubbed in french :(
<soul-d>
otherwise id probably make one with an elastic band some tape and a coke can
<azonenberg>
lol
<berndj>
that was my favourite show when i was a kid. i DON'T want to see reruns now and ruin the memory
<soul-d>
true :)
<soul-d>
but din't see them all :P
<azonenberg>
Well right now I'm busy working on something unrelated to IC fab (yes, I do other things too :P)
<azonenberg>
FPGA switching fabric design :D
<soul-d>
although i have studied fpga a bit it doesn't tell me anything :P you mean the underlying tech to make the general logic ?
<azonenberg>
No
<azonenberg>
i mean a 16 port 12.8 Gbps-per-port switching fabric
<azonenberg>
to connect various elements on my SoC
<soul-d>
k, not that deep in designing yet so can't visualize it :P
<azonenberg>
It's basically the equivalent of a 16-port 10gbe switch
<azonenberg>
Except each packet is, instead of an ethernet frame, my own interconnect format
<azonenberg>
which includes source/dest port numbers (only one device allowed per port so no MAC addressing etc), 32 bits of address, a read/write bit, and 64 bits of data if it's a write
<soul-d>
got some money think gonna check out the cheap pcb chemical
<smeding>
1.6u but yeah
<azonenberg>
wanna bet your asic runs slower than the fpga version? :P
<azonenberg>
and lol, 1.6um is within the range of what i could be able to fab soon
<smeding>
no, that isn't a very fair bet
<smeding>
got ion diffusion down yet? p
<smeding>
:p
<azonenberg>
fair to the asic?
<smeding>
yeah
<azonenberg>
and i'm talking lithorgaphy
<azonenberg>
doping is one of the processes i havent looked at yet
<smeding>
anyway, we were basically told "don't expect the ASIC to work"
<azonenberg>
LOL
<azonenberg>
that bad?
<smeding>
between us being second-year EE undergrads and the people fabbing it being people who have never been in a clean room before
<smeding>
there is not a lot of yield
<azonenberg>
lolwut?
<azonenberg>
wow lol
<smeding>
they save money by having the clean room course consist of fabbing the ASIC for our project
<smeding>
i suppose
<azonenberg>
But still, lol
<smeding>
yeah it's pretty silly
<smeding>
the code some people put out is ridiculous though
<smeding>
i like to think what i wrote is reasonable, maybe even good VHDL
<azonenberg>
lol
<azonenberg>
i'm working on verilog but i'm still a relative novice
<smeding>
we have some dinky IR communications project, i wrote most of the IR subsystem and helped other groups
<azonenberg>
only written a few tens of thousands of lines total
<smeding>
one group wrote a module that receives ASCII and determines where it goes on the little LCD we hook up
<smeding>
from the IR decoder and the keyboard interface
<azonenberg>
Does it work on the FPGA?
<smeding>
nope
<azonenberg>
Lol
<azonenberg>
and you expect it to work on the asic? :P
<smeding>
i've given up hope
<smeding>
:p
<azonenberg>
lol
<smeding>
they claim they have fixed things though
<azonenberg>
The fab lab class in my school uses a single mask set that's probably ten years old
<smeding>
but looking at the design i don't see how anything short of a redesign could have fixed it
<azonenberg>
(i havent taken it)
<azonenberg>
But eevryone makes the same basic design
<azonenberg>
just some caps and transistors hooked up to probe pads
<azonenberg>
on a 2" wafer
<smeding>
ah
<smeding>
sounds reasonable
<smeding>
anyway, you should see the design plans for this module... they 'designed' a D flip-flop, used it to implement a register, used two of those and a multiplexer, and it's controlled by an icky half-state-machine
<smeding>
(the library comes with standard blocks and the synthesis engine is fairly intelligent)
<azonenberg>
lol
<smeding>
in their place i would just have made a big Moore machine and let the synth handle it
<smeding>
at least at first, maybe optimisation would require me to split it up
<azonenberg>
optimization? How slow is the current code?
<smeding>
oh, it's not slow enough to matter
<smeding>
the main limitation is chip size
<azonenberg>
oh lol
<smeding>
we can do 80k transistors max, and on SoG that's not that much
<azonenberg>
i'm used to optimizing for speed on a giant chip
<azonenberg>
and lol, 80k transistors? That's like what, 20k gates not even counting barrier transistors?
<smeding>
less, probably
<azonenberg>
So maybe 10k usable?
<azonenberg>
and i thought my 50k gate fpga was small
<soul-d>
i might have 50k if i add up all my fpga's :P
<smeding>
i still can't find where the 80k limit comes from though
<soul-d>
or difrent from le's ? :P
<azonenberg>
lol, yes
<smeding>
the manual says 200k but we were assured by the tutor the limit is 80k
<azonenberg>
a LUT is several gate equivalents
<azonenberg>
and a LE is usually several LUTs
<smeding>
anyway an inverter occupies 4 transistor positions
<azonenberg>
what about a 2NAND?
<smeding>
six
<azonenberg>
thats usually the definiteion of a gate-equiv
<azonenberg>
i see
<smeding>
then you add barrier transistors and wiring room
<smeding>
and you get efficiencies of something like 30%
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<smeding>
in terms of transistors used for switching vs transistor positions occupied
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<smeding>
so that's like, 6k gates?
<azonenberg>
lol
<azonenberg>
wow
<smeding>
the only groups who have a full design working on the FPGA have given up on trying to fit it onto the ASIC i think
<azonenberg>
lol
<azonenberg>
you could like barely fit a UART in that
<smeding>
hm, then i might be exagerrating
<smeding>
because we have a sort of UART, and more
<smeding>
well, it's not an UART... the receive portion is ugly, from what i've seen
<azonenberg>
Lol
<azonenberg>
well ok, you could fit a uart and change