<azonenberg>
i use something similar for drying stuff
<azonenberg>
You want high pressure
<azonenberg>
a blow dryer is trying to *evaporate* stuff
<azonenberg>
with this, the goal is to physically blast the droplets off the surface
<azonenberg>
if it dries on the sample any residual contaminants will be deposited
<azonenberg>
but if you knock them off while liquid they stay in the solvent
<azonenberg>
make sense now?
<B0101>
hi azonenberg
<B0101>
I did found a place where they sell wafers, but I think it is mostly asia shipping only, may i add it to the wiki?
<azonenberg>
Sure
<azonenberg>
The more the merrier
<azonenberg>
For all you know we'll be getting an asian guy in here soon who wants to know where to buy silicon
<azonenberg>
if you want to add any resources whatsoever, go for it
<azonenberg>
swkhan: how did your plating experiments go?
<swkhan>
i am still in the "measure twice" phase of "measure twice cut once" =(
<azonenberg>
swkhan: Well, at least you didnt jump into anything
<swkhan>
i came across a good paper that uses copper sulfate (which i can make or buy for cheap), boric acid (apparently i had it in the lab), and hf (don't have... could maybe buy but i want to take the hf safety class first)
<azonenberg>
Yeah, especially if you are dealing with concentrated
<azonenberg>
its not something to treat lightly
<swkhan>
i don't know what the hf is for and i'm not sure if i can substitute it with sulfuric acid or phosphoric acid
<swkhan>
if i need a weak acid then probably phosphoric acid...
<azonenberg>
My guess is that its for stripping oxide, in which case you cannot substitute
<swkhan>
hmm, they have two solutions: (a) 0.013 M CuSO4 + 0.50 M Na2SO4 and (b) 0.013 M CuSO4, 0.186 M HF, 0.5 M H3BO3
<swkhan>
i want to use Na2SO4... i wanted to see if i could make it first but again... everything is so dangerous =\
<swkhan>
i was thinking NaCl + H2SO4 -> Na2SO4 + HCl
<swkhan>
which ultimately happens if provided enough heat i think
<azonenberg>
Semiconductor stuff has quite a few nasties, thats one of the hardest problems to solve in a hobbyist friendly process
<azonenberg>
trying to eliminate CVD etc
<swkhan>
but i don't know what i'd do with HCl afterwards
<swkhan>
i see
<swkhan>
metal silicides are still something i'm really interested in
<azonenberg>
I couldnt get around HF but i at least dont need concentrated, just realyl dilute
<swkhan>
could you use HCl?
<swkhan>
HF is a weak acid right?
<azonenberg>
swkhan: yes, it's weak
<azonenberg>
the H+ isnt what's active in most reactinos you'd use it for
<swkhan>
i'll stop teasing you and give you the paper already =p
<azonenberg>
it's the F-
<azonenberg>
So rather than replacing it with another weak acid you might want to consider an alternative source of fluoride ions
<azonenberg>
preferably something a little safer than, idk, ClF3 ;)
<azonenberg>
idk if you've heard of it but, well, let me put it this way
<azonenberg>
asbestos and glass ignite on contact with it :P
<azonenberg>
"In an industrial accident, a spill of 900 kg of chlorine trifluoride  burned itself through 30 cm of concrete and 90 cm of gravel beneath"
<azonenberg>
"It is, of course, extremely toxic, but that's the least of the problem. It is hypergolic  with every known fuel, and so rapidly hypergolic that no ignition delay  has ever been measured. It is also hypergolic with such things as  cloth, wood, and test engineers, not to mention asbestos, sand, and  water  with which it reacts explosively"
<swkhan>
wow, that's very useful
<azonenberg>
"hypergolic with test engineers" lol
<swkhan>
we had lots of problems with contamination and undesirable deposition in our flow lines
<swkhan>
i'll see if i can ask my advisor if we can use it at some point
<swkhan>
In the semiconductor industry, chlorine trifluoride is used to clean chemical vapour deposition chambers.[14] It has the advantage that it can be used to remove semiconductor material from the chamber walls without having to dismantle the chamber.[14] Unlike most of the alternative chemicals used in this role, it does not need to be activated by the use of plasma since the heat of the chamber is enough to make it decompose and react with the semicondu
<swkhan>
lol hypergolic with test engineers. aww poor test engineers
<azonenberg>
Look into alternatives first
<swkhan>
okay
<azonenberg>
it's useful but so extremely reactive you dont want to keep it around without a good reason
<azonenberg>
if you thought chlorine or fluorine alone was bad, this stuff is worse
<swkhan>
=\
<swkhan>
i'm still leaning towards the CuSO4 + Na2SO4 solution
<swkhan>
but i don't like the electrode they used
<azonenberg>
What was it?
<azonenberg>
Thats a pretty common plating bath iirc
<swkhan>
i am okay with this part... i think
<swkhan>
"technical grade (100) oriented Si wafers n doped for a resistivity of 3 to 7 ohmcm, and electrical contact to each substrate was made through a GaIn or GaAl back contact." << don't like that last part about GaIn and GaAl
<swkhan>
"an adhesive tape was used to mask off all the substrate except for the area on which deposition was desired" << love that part
<swkhan>
they clean the substrate with 10% HF then put into the electrodeposition cell
<swkhan>
they had a 3 electrode cell << also something i don't like too much but it seems like a lot of people used it to make for more uniform films
<azonenberg>
I wouldnt use adhesive though
<azonenberg>
if you want to do a lift-off process use photoresist
<azonenberg>
That will give you features as fine as you want
<swkhan>
"potentials were measured against a saturated calomel electrode (SCE) which was placed as close as possible to the Si surface to minimize the ohmic potential drop in the electrolyte
<swkhan>
"
<swkhan>
hate that part
<swkhan>
photoresist doesn't like being etched away in strong acids even?
<azonenberg>
you can do a contact mask on transparency film with a desktop printer
<swkhan>
er.. i guess i don't have strong acids here
<azonenberg>
Sure you do - HCl + H2O2?
<azonenberg>
And i use my photoresist as a mask for etching in SC2 on a routine basis
<azonenberg>
thats how i do printed circuit boards
<azonenberg>
30 microns copper on fiberglass-epoxy composite, coat in photoresist, expose, develop
<swkhan>
the paper doesn't use hydrochloric acid or hydrogen peroxide
<azonenberg>
then etch in HCl:H2O2
<swkhan>
i see
<azonenberg>
My point is, the resist is unreactive in acids
<swkhan>
i see
<azonenberg>
it will be eaten quickly in strong bases
<swkhan>
check out saturated calomel electrode btw. it's basically mercury chloride if i remember right
<azonenberg>
and the stuff i use is permeable to fluoride
<azonenberg>
as in HF does not damage the polymer but F- diffuses through it and will attack the underlying surface
<swkhan>
huh interesting
<B0101>
azonenberg: wait there's a policy. minimum order 1000!
<azonenberg>
B0101: Lol
<azonenberg>
Yeah, thats a problem with a lot of the nice places
<swkhan>
well remember there's 2 electrolytic solutions they used separately
<swkhan>
(a) 0.013 M CuSO4 + 0.50 M Na2SO4 and (b) 0.013 M CuSO4, 0.186 M HF, 0.5 M H3BO3
<swkhan>
i don't have HF or Na2SO4, but given that.. which one would you go for?
<swkhan>
i like the fact that the former doesn't require as much stuff
<azonenberg>
Yeah, and specifically doesnt require HF
<swkhan>
i like this paper because they are a little bit more upfront about what they did!
<azonenberg>
That alone is a big point in its favor
<azonenberg>
(no hf)
<swkhan>
they also did nickel and cobalt plating in this one btw
<azonenberg>
interesting
<azonenberg>
Electroless Cr is likely to be a really good option for you btw
<swkhan>
and multilayers using all of those
<azonenberg>
since Cr has super good adhesion
<azonenberg>
to glasses etc
<B0101>
azonenberg: here, you cannot even get basic acids like HCL (unless you're like me who posses a license)
<azonenberg>
B0101: what kind of license?
<swkhan>
wow
<swkhan>
to spill
<B0101>
Chemical license
<azonenberg>
i mean, whats involved in getting one over there?
<azonenberg>
here the most the supplier would do is mark the package as "adult signature required"
<azonenberg>
except for really nasty stuff
<azonenberg>
but you can buy dilute HF in grocery stores
<B0101>
disposal techniques must be told to authorities
<azonenberg>
and HCl online as an ORM-D consumer commodity (special class midway between normal and hazmat)
<azonenberg>
what i meant is, is it difficult to get one?
<swkhan>
if you bake off the water, would you get more concentrated HF or does HF boil away with the H2O?
<azonenberg>
or can any hobbyist who's interested get one?
<B0101>
and you must be working in a lab, or company which uses them and its is very difficult to get
<azonenberg>
swkhan: heating hf = hf vapor
<azonenberg>
usually
<swkhan>
=\
<azonenberg>
And you do not want that lol
<B0101>
azonenberg: and yeah, hobbyists cannot buy it
<azonenberg>
Where is this again?
<swkhan>
omg
<swkhan>
Hydrogen fluoride is a highly dangerous gas, forming corrosive and penetrating hydrofluoric acid upon contact with tissue. The gas can also cause blindness by rapid destruction of the corneas.
<azonenberg>
swkhan: Yeah, sounds right
<azonenberg>
the rule in the cleanroom here is that if you see a spill, you assume the worst
<azonenberg>
namely concentrated HF
<swkhan>
took a lifetime to build up my pretty little eyes and it only takes it a little while to ruin it =(
<azonenberg>
punch the spill alarm and evacuate
<swkhan>
wow
<swkhan>
i wish i got training like that
<azonenberg>
the only exception is if you're the one that spilled it
<swkhan>
my safety training was stuff everyone mocked
<azonenberg>
and you know its something else
<swkhan>
mm
<swkhan>
O_O
<swkhan>
Boiling point
<swkhan>
19.5 °C, 293 K, 67 °F
<azonenberg>
Yeah, normally hf is used as a solution in water
<azonenberg>
nobody uses it pure
<B0101>
Azonenberg: I put to you this in a simpler way: here in SG. you cannot buy a license unless you're working for a lab or company who uses chemicals. and... hobbyists cannot buy it
<azonenberg>
Even my 3% HF i'm careful with (use no more than 1CC at a time, gloves, lab coat, goggles, and depending on the conditions sometimes a face shield)
<azonenberg>
and if i'm heating it it's in a sealed container to lock in any vapors
<swkhan>
oh singapore
<B0101>
Azonenberg: sorry if i got you confused. earlier
<swkhan>
here's some gum B0101 =)
<swkhan>
what sort of gloves do you use?
<swkhan>
we have nitrile gloves
<azonenberg>
swkhan: I use thin nitrile most of the time since i'm not handling a significant amount
<swkhan>
4 mil? i think that's what we have
<azonenberg>
and while it would diffuse through, the 3% would take a few seconds at least to penetrate
<azonenberg>
which is enough time to peel it off :P
<swkhan>
lol
<B0101>
swkhan: its banned, and even if it isn't, i don't eat gum
<azonenberg>
I do have norfoil as well, which i'd use if i felt the risk of a spill was significant
<swkhan>
it's banned?! i knew you weren't supposed to spit it on the ground or you'd get in trouble.
<azonenberg>
check out the chemical resistance charts for this stuff, its amazing
<B0101>
Swkhan: they banned it as a idiot stuck the gum to the door of a train
<B0101>
Swkhan: from the inside. causing the sensors to act up
<azonenberg>
they're a little slippery so i usually double glove with nitrile
<swkhan>
wow
<azonenberg>
the nitrile is just there to make the outside a bit less slippery so i can grab things easily
<azonenberg>
It also helps reduce the risk of a scratch tearing the norfoil
<swkhan>
oh wow! i could still make this
<swkhan>
NaOH and H2S04 -> Na2SO4 + 2H2O
<swkhan>
yay!
<azonenberg>
Nice
<swkhan>
i love knowing chemistry now. i don't feel crippled
<swkhan>
but i still do with my lack of physics knowledge
<azonenberg>
and is the bath used for electroplating then?
<swkhan>
then i have sodium sulfate. i need to make copper sulfate or at least buy it
<swkhan>
i'm going to surprise my labmates tomorrow =)
<azonenberg>
If you are going to synthesize it, dont use copper tape
<azonenberg>
use something cheap
<swkhan>
i have copper wire too
<swkhan>
and we have high purity copper as well. i was planning on using it as an electrode
<azonenberg>
Use a bit of that, then
<swkhan>
but i want to understand the non-solution part of setup
<swkhan>
i don't get how they made the electrical contacts all work out
<swkhan>
i need to have a procedure so tomorrow i can focus on being safe
<azonenberg>
Cant help you there, chem (especially electrochemistry) is one of my big weak points
<azonenberg>
i'm already a comp sci studying EE in his spare time, adding chem to that would take more time than i have :p
<B0101>
HCl + NaOH = H2O + NaCl... quite a good way to "dispose" HCl
<azonenberg>
B0101: Yeah, last time i had extra i needed to get rid of i did just that
<azonenberg>
titrate to neutral pH and either drain dispose or evaporate the water
<azonenberg>
thing is, most of my acid waste now has metal ions in it
<azonenberg>
so its a lot more complex to get dispose of
<azonenberg>
like i said earlier the easy solutoin is to send it out for professional disposal
<B0101>
Wow, people are asking me if they could make HCl from salt and water
<azonenberg>
lol
<azonenberg>
I think you can do it from acetic acid and salt though
<azonenberg>
turns into HCl and sodium acetate
<berndj>
swkhan, anecdote: in a telescope making list i saw a guy once claim that he basically etched the mirror glass with HF that he derived from HCl + fluorspar (CaF2)
<azonenberg>
berndj: Yeah, that's doable
<azonenberg>
i do not recommend attempting it
<azonenberg>
a) purity is poor
<azonenberg>
b) worse yet, it's uncontrolled
<azonenberg>
you are very likely to be emitting a lot of HF vapor
<azonenberg>
the one guy i know who attempted the synthesis in a tray outside ended up retreating inside and closing the door when he saw how fast the reaction was proceeding
<azonenberg>
it ended up eating a hole in the patio
<B0101>
is away: "Lunch"
<berndj>
B0101, don't people have swimming pools where you are? how can you not be able to get HCl??
<azonenberg>
yeah - i get my hcl from a biodiesel supplier and it's a little better purity than pool acid but is the same concentration
<azonenberg>
just better grade
<berndj>
<azonenberg> the only exception is if you're the one that spilled it // and you know its something else  "don't worry guys it's just ClF3!"
<azonenberg>
lol
<azonenberg>
Still an exception
<azonenberg>
In that case, you do the same thing - except you run out a little bit faster than if it was "just" HF
<azonenberg>
:P
<berndj>
azonenberg, when double-gloving, do the layers glide over each other easily?
<berndj>
don't want them to chafe!
<azonenberg>
Depends on the materials
<azonenberg>
Norfoil is very slippery
<azonenberg>
so nitrile fits over it smoothly
<azonenberg>
I also use XL for the outside layer over L intner
<azonenberg>
inner*
<azonenberg>
The idea is that the norfoil is your main protective layer and the nitrile is there both for abrasion protection and improved grip
<berndj>
how do you recognize nitrile if it isn't labelled?
<azonenberg>
It's *usually* blue or purple but not always
<azonenberg>
i have white (undyed) nitrile gloves that look a lot like latex
<azonenberg>
telling the two apart without chemical testing is tricky
<azonenberg>
the best way is to check the datasheet
<azonenberg>
You'd want to have that anyway for chemical resistance charts etc
<reportingsjr>
and remember kids, never double bag latex
<azonenberg>
:p
<B0101>
is back (gone 02:37:24)
<B0101>
berndj: they don't use HCl
<B0101>
they use Sodium Hypochlorite
<azonenberg>
Hmm, interesting
<azonenberg>
i dont remember the details of the reaction
<azonenberg>
i know its fluorite plus something
<B0101>
azonenberg: On the topic of chemicals with electronics, HCl + H2O2 is used as PCB etchants
<B0101>
thats what we all know
<azonenberg>
B0101: It's useful for silicon cleaning (second step in the RCA clean) as well since it removes metal contamination
<azonenberg>
good for wet etching thin films of copper and aluminum
<azonenberg>
HCl (must be without H2O2) works on chromium but you need to touch it with a piece of aluminum first to electrolytically remove the CrO2 passivation layer
<swkhan>
gah the most knowledgeable person here can't help me =\
<swkhan>
i wish more people were like azonenberg
<swkhan>
willing to pick up completely different, new fun things =)
<azonenberg>
swkhan: i do too... gets lonely at times lol
<azonenberg>
hard to find anyone i can have a technical conversation with that doesn't get lost the second i cross boundaries from one discipline to another
<azonenberg>
heck, half the EE majors here know less about lithography than i do
<azonenberg>
difficult to find someone i can go to for advice :(
<B0101>
azonenberg: I'm sure there's someone who knows a lot about lithography
<azonenberg>
Sure, the guy who runs the stepper in the cleanroom here
<azonenberg>
But he's too busy to talk to people whose grants aren't paying for the equipment :(
<azonenberg>
i'm talking other students etc
<azonenberg>
its like an asymptotic function
<swkhan>
lol
<azonenberg>
as a baby, anyone can teach you what you want to know - how to talk, etc
<azonenberg>
the more you learn, the less people there are you can learn from in your field of interest
<azonenberg>
The subset of those people that you know exist is even smaller
<B0101>
true
<azonenberg>
And once you get to the graduate level doing original research, you're now one of them
<azonenberg>
nobody else knows any more than you do about your chosen field
<azonenberg>
in that one narrow area
<azonenberg>
So they can offer advice but not give you the answer
<azonenberg>
I'm obviously not there in terms of litho, but the point stands - its getting harder to find people who can help lol
<azonenberg>
Especially considering that as a hobbyist with no budget i'm restricted to those who will help at no cost
<azonenberg>
rather than those who work at a fab and won't look at you if you arent a customer :P
<West0n>
So for homebrew litho, where do you get you base material?
<West0n>
(The silicon boules)
<West0n>
Or polished cuts
<azonenberg>
Wafers, actually - i buy them sliced and polished
<azonenberg>
the second method described in the paper (camera port)
<West0n>
I am guess its a bit more advanced then normal pcb photo exposure setup?
<azonenberg>
very similar
<B0101>
sodium carbonate as developer?
<azonenberg>
but its projection rather than contact
<azonenberg>
B0101: I've heard it works too
<azonenberg>
Never used anything but NaOH myself
<West0n>
Contact for pcb etch?
<azonenberg>
You may have to fool around a bit to find the right concentration
<azonenberg>
West0n: Most people doing PCB stuff use contact litho
<azonenberg>
which by definition is 1;1 scale
<azonenberg>
I use projection litho
<azonenberg>
mask is placed behind a lens and projected onto the wafer/die
<azonenberg>
depending on the objective you can get different levels of reduction
<azonenberg>
the image i just pasted was designed and printed at 600DPI on a laser printer, lines are 5 pixels wide
<azonenberg>
(thats the smallest that resolves clearly)
<azonenberg>
That forms ~200um wide lines on the transparency
<B0101>
azonenberg: if that is true, then i will curse myself for buying positive developer solution for $6
<azonenberg>
it's then reduced optically by 10x (which gives pretty good results) or 40x (still trying to improve yields, havent gotten anythign to work)
<azonenberg>
or whatever else your objective is
<azonenberg>
I have a 100x immersion objective but i dont want to try immersion lithography until i have good yields on the larger processes
<azonenberg>
the immersion objective could in theory give me 2um design rules
<azonenberg>
Which i could then shrink to 1 by use of double patterning
<azonenberg>
And if i switched my 600DPI printer out for a 1200, i could theoretically hit 500nm
<azonenberg>
i know my optics are capable of it, i can see 500nm features using the same objective
<azonenberg>
That's at least a year out and i expect it will start being impacted by dust etc at that point (if not before)
<azonenberg>
West0n: Did you see the pic i pasted?
<West0n>
Yes
<azonenberg>
Oh, and the bigger problem is that the aspect ratio i can hit with KOH is such that i can't make deep features of that size
<azonenberg>
And i dont have DRIE capabilities for obvious reasons
<azonenberg>
Realistically i think most of my MEMS work will be done at significantly larger sizes - 5-20 um design rules
<azonenberg>
The main reason i'm continuing to shrink rather than focusing on improving yields is that i enjoy the challenge :P
<azonenberg>
Realistically i have no idea what i would do with a 500nm fab process lol
<azonenberg>
At least not until i get the budget for dopants and all of the trimmings and trappings i'd use for CMOS
<azonenberg>
And yields will likely be poor as that's really pushing the limits of what i could do with the setup
<azonenberg>
2um, without double patterning or the high DPI printer, is still going to be tough because i'd need to find an immersion medium that is compatible with the process and can be cleaned off
<azonenberg>
for example most oils are out
<azonenberg>
water might work but i'd need a water compatible objective
<azonenberg>
And in any case the first step is to work on improving the 5um process to the point that i get workable yields
<azonenberg>
Anybody here good with cross section microscopy sample prep? :P
<azonenberg>
I started out having 1500 grit sandpaper and 60nm colloidal silica
<azonenberg>
just ordered a selection of diamond polishing compounds from ted pella that are in the 6um to 250nm range so hopefully that will be enough
<swkhan>
sandpaper works?
<swkhan>
wouldn't that give you a lot of silica dust?
<swkhan>
i don't have any experience... i'm just wondering aloud
<azonenberg>
i actually started out with a really coarse abrasive, like 300 grit sandpaper
<azonenberg>
Yes, it makes dust
<swkhan>
wow
<azonenberg>
but you can clean it off
<azonenberg>
That was to grind halfway throuhg the sample
<azonenberg>
so i'd get to the rough area i wanted
<azonenberg>
since i didnt have a suitable wire saw on hand
<azonenberg>
then 1500 grit to get a smooth but not polished surface
<swkhan>
so what do you want to see? thickness?
<swkhan>
of each layer*?
<azonenberg>
then i realized i needed something finer than that but coarser than the 60nm
<azonenberg>
so i got the diamond stuff which hasnt arrived yet
<azonenberg>
Thickness and slopes
<azonenberg>
i want to see how steep the vertical edges of an etched layer are
<azonenberg>
measure undercut
<azonenberg>
etc
<swkhan>
i wonder if your abrasive would affect the slopes
<bart416>
Mhhh azonenberg is it something round?
<azonenberg>
The abrasive? I'm not sure
<bart416>
No I meant what you're trying to cut
<azonenberg>
the colloidal silica almost certainly is
<azonenberg>
oh
<bart416>
If it's a round shape, use a lathe
<azonenberg>
no, its a silicon die lol
<azonenberg>
rectangular and being cross-sectioned along the thin axis
<azonenberg>
And i need it polished down to submicron
<bart416>
yeah, you'd need an electron beam cutter :P
<azonenberg>
ideally, i want to be able to see the 5nm thick Cr adhesion layer :P
<azonenberg>
but thats not likely
<azonenberg>
what i do want is to be able to see the 200-1000nm of copper, the ~50nm of tantalum oxide, and the few microns of photoresist
<azonenberg>
along with edge profiles for each (or at least overetch estimates)
<swkhan>
when would you use an e-beam cutter versus an ion-beam cutter?
<swkhan>
like e-beam versus fib
<azonenberg>
swkhan: Not familiar with e-beam for cutting
<azonenberg>
only for lithography exposure
<azonenberg>
or evaporation
<azonenberg>
so i dont know details of what they're good for
<azonenberg>
The only nanoscale cutting tool i'm even somewhat familiar with is a FIB and while i know what they are in theory i've never used one myself
<azonenberg>
i got to sit next to one though :P
<azonenberg>
while using the SEM in the cleanroom
<azonenberg>
fib is right behind it
<swkhan>
oh cool =)
<azonenberg>
Again, this is all part of the process characterization step
<swkhan>
we're getting a fib soon. rie too =)
<azonenberg>
once it have this figured out, you wont need it for actual processing
<azonenberg>
once i*
<azonenberg>
and cool
<swkhan>
i see
<azonenberg>
DRIE or just regular?
<swkhan>
i think both eventually
<swkhan>
just regular for now
<azonenberg>
and if you get to use the fib have fun... those things are amazing
<azonenberg>
re RIE, i want that kind of capability in my fab :P
<azonenberg>
but dont expect it any time soon
<azonenberg>
anisotropic silicon etch: poor man's DRIE ;)
<azonenberg>
yay KOH!
<swkhan>
lol. but you don't have to pay for your lab once it is setup
<swkhan>
we have to essentially "rent" services
<swkhan>
which... we perform, so at least we save on labor
<swkhan>
because i'm worthless =(
<azonenberg>
You've been around long enough you should know by know
<azonenberg>
cheap foreign labor, academic style
<azonenberg>
= grad student
<bart416>
azonenberg, doesn't even have to be a grad student
<bart416>
cheap labor, academic style = students
<azonenberg>
True, sometimes undergads are abused worse lol
<azonenberg>
But they also know less and are less valuable to the faculty
<azonenberg>
so they wont necessarily make you spend as much time on the project
<bart416>
Depends
<bart416>
The issue I'm currently finding is that we're actually not allowed to participate in any research projects as undergraduates >_>
<bart416>
So it's hard to score your name on publications
<azonenberg>
not allowed to? o_O
<bart416>
Maybe if you ask really really really nice
<bart416>
But not really no
<bart416>
They just employ full time researchers
<bart416>
But not even I with my near perfect grades get offered a chance to participate...
<azonenberg>
Around here you usually have to ask, but they're pretty willing
<azonenberg>
Also, wow... looks like i was pretty lucky to have not lost power
<bart416>
Doesn't your college/university have some generators?
<azonenberg>
power company reports 277 people w/o power just a few blocks south of me
<azonenberg>
And i live off campus in an apartment downtown
<bart416>
Wow, somebody in the US that lives off campus!
<azonenberg>
The school has both battery and generator backups on some critical infrastructure
<azonenberg>
like the core servers, chillers in the biotech, fume hoods that were not scheduled to be shut down, etc
<azonenberg>
but it doesnt cover everything
<azonenberg>
Most of their utilities are underground so their impact was minimal
<azonenberg>
as i understand there were a couple of brief glitches but no long-term outages
<azonenberg>
My immediate area seems to have been surprisingly lightly impacted
<bart416>
You guys should really put your electric cables underground
<azonenberg>
On campus, they are
<azonenberg>
As are many of the distribution lines
<azonenberg>
but it doesnt help if the tunnel gets flooded :P
<azonenberg>
thats what took out a lot of power in NYC afaik
<bart416>
I'm not talking about putting them in the underground transportation tunnels
<bart416>
I'm talking about putting them 1-3m under the street
<azonenberg>
I dont know exact details
<azonenberg>
but also, transformer sites etc are potential weak points
<bart416>
In water tight shielding
<bart416>
And if you bring it up to surface level it first has to go up 2 meters at the very least and then as soon as possible enter a fuse box
<bart416>
So no water can get to it
<azonenberg>
yeah, makes sense
<azonenberg>
i think the problem is that there's a lot of older equipment around
<bart416>
Here their comment was "get new equipment" :P
<bart416>
Honnestly, jogging pants, clearly artificial fabric tshirt considering it melted into his skin o_O
<bart416>
And then trying to saw a 20kV line, lol
<bart416>
Bah, it sucks having to wait for a 800 euro paycheck >_>
<bart416>
+ another 60 euro from another place >_>
<azonenberg>
Lol i know the feeling
<azonenberg>
My school is great at taking your money
<azonenberg>
less good at giving it out
<azonenberg>
hopefully my teaching assistantship will start paying up soon because i have rent due in ~3 weeks
<azonenberg>
:p
<lekernel>
euro?
<lekernel>
I thought you were in US
<azonenberg>
lekernel: i am but i dont think bart is
<swkhan>
azonenberg: very personal question... how much do you make in a year?
<swkhan>
i will be happy if i get about 12k a year starting next year
<swkhan>
i think the highest i can go is 22k
<azonenberg>
In theory? min stipend for grad students here is 18k before taxes
<swkhan>
that's after taxes btw
<azonenberg>
which is what i was offered
<swkhan>
i hate how we're so low on the totem pole =(
<azonenberg>
in practice? we'll see :P
<azonenberg>
My guess is "not much" lol
<bart416>
Here TAs get about 1800 euro / month
<azonenberg>
Depends a lot on cost of living though
<bart416>
At the start TA pays about as much as the industry here actually :S
<bart416>
But after a few years working in industry your paycheck is way way waaaaaaaaaaaaaaaaaaaaaaaaaaay higher
<azonenberg>
lol
<azonenberg>
Um, yeah
<bart416>
So how much hours / week do you have to teach azonenberg ? :P
<azonenberg>
bart416: nominally? 20
<azonenberg>
realistically? no idea
<bart416>
What subjects?
<azonenberg>
i will be havnig office hours twice a week for two horus
<azonenberg>
hours*
<azonenberg>
each session will have one hour for one class and one for the other
<azonenberg>
computer organization / crypto 1
<bart416>
Sounds boring :P
<bart416>
Did you have any choice or was it simply assigned?
<bart416>
A friend of mine is Ph.D. student/TA for chemistry
<bart416>
And the professor he was assigned to got sick (cancer)
<bart416>
He had to do his own classes + the professor's
<bart416>
heh
<bart416>
+ the administration + the conventions + everything else you can think off :')
<bart416>
And his wife was pregnant at the same time >_>
<bart416>
(Mind you, he was happy with all of those things)
<azonenberg>
Both professors requested me as their TAs
<azonenberg>
and i was ok with it
<azonenberg>
both were among my favorite classes as undergrads
<azonenberg>
and i know the material inside out and backwards
<azonenberg>
comporg covers x86 and mips plus low level cpu arch
<azonenberg>
i'm implementing mips in an FPGA :P
<bart416>
Ah
<bart416>
The name is weird :|
<azonenberg>
and know x86 decently well as well
<bart416>
Here thats called computer achitecture, lol
<kristianpaul>
lm32? ;-)
<azonenberg>
crypto, well, i'm kind of a phd student in security
<azonenberg>
so if i dont like crypto i'm in the wrong field lol
<bart416>
Thought it was boring network topology :P
<azonenberg>
kristianpaul: I'm implementing several softcores
<azonenberg>
the simplest is a custom 8-bit 3-stage pipelined architecture
<azonenberg>
the complex one is MIPS 1
<azonenberg>
with 5-stage pipeline
<swkhan>
azonenberg: why is this stuff your hobby and CS your bread and butter?
<swkhan>
instead of the other way around?
<swkhan>
CS is cheaper to do on your own certainly
<azonenberg>
swkhan: I like all of it and couldnt decide exactly what i wanted to study
<swkhan>
i see. same here =(
<azonenberg>
i'm not a big fan of math which meant i didnt want to take the intro EE classes that covered analog stuff
<azonenberg>
So CS it was
<swkhan>
lol, isn't CS full of math too?
<azonenberg>
it's a different kind of math
<kristianpaul>
analog will hunt you fure sure
<kristianpaul>
time time time :)
<swkhan>
so set theory type stuff over vector calculus / differential equations?
<azonenberg>
kristianpaul: I like to say that if a circuit i built has anything but 0 and 3.3V on it (except during clock edges), i probably messed up in the design somewhere
<swkhan>
lol
<azonenberg>
i've since added 5, 1.8, and 1.2 to the acceptable list
<azonenberg>
swkhan: and yes
<swkhan>
lol acceptable! you're so funny =p
<berndj>
yikes azonenberg i hope you didn't do low level org of x86!
<azonenberg>
berndj: Lol, no we didnt do too much of that
<berndj>
i'd be half interested, but that would be cruelty against students
<azonenberg>
most of the really low level stuff was mips
<azonenberg>
and having implemented a good chunk of mips 1 in an FPGA i know it at the pipeline internals level lol
<berndj>
yeah, we did that too.  patterson & henessy?
<azonenberg>
Yep
<berndj>
timeless book
<azonenberg>
I used the 3rd edition
<azonenberg>
the class is now on the 4th
<azonenberg>
and my mips implementation is currently on hold as it wont fit in the tiny XC3S50A i have on hand lol
<azonenberg>
So i'm doing an 8-bit design until i finish the dev board for a larger processor lol
<lekernel>
you could get a M1 instead :-)
<azonenberg>
lekernel: XC6SLX75 looks yummy all right
<azonenberg>
but i want to design the board and pick out the components
<berndj>
build a subtract-and-branch-if-negative processor. that should fit
<azonenberg>
berndj: lol, the design i'm doing is a little more complex
<azonenberg>
its heavily inspired by MIPS with just a little bit of x86 and 8-bit PIC in there
<azonenberg>
shrunk down to 16 bit instructions and an 8-bit datapath
<lekernel>
sounds challenging in a 3s50a
<azonenberg>
lekernel: actually, i have everything implemented except the shifter and memory controller and it's using just over half
<azonenberg>
i was hoping i could fit two of them in a 50a but that might not happen
<azonenberg>
this is the version with 8x registers and 4-level hardware stack
<azonenberg>
but its parameterizable to 4-8-16 regs and 2-4-8 level stck
<azonenberg>
same binary instruction format
<azonenberg>
right now its using 204/1408 FFs, 779/1408 LUTs, one block ram for instructions
<bart416>
<azonenberg> i'm not a big fan of math which meant i didnt want to take the intro EE classes that covered analog stuff <-- The analog part of electronics is the most fun :P
<swkhan>
i agree! =D
<azonenberg>
bart416: and thats why i stick to CS and digital whenever possible :p
<bart416>
You can do horribly complicated math with some opamps, resistors and diodes, heh
<lekernel>
ah, 1400 LUTs? I thought it had more like 500...
<azonenberg>
lekernel: the 50a has 1408 FFS/LUTs, 704 slices, 68 IOBs, 24 BUFGMUX, 3 block RAM, 3 MULT18x18
<azonenberg>
Still hoping i can fit two copies of the area optimized (4 registers, 2 level stack) version into the 50a
<azonenberg>
this is the general purpose design
<azonenberg>
then the 16-reg 8-level is even bigger
<azonenberg>
oh, and this design passes static timing for 90 MHz right now
<azonenberg>
with a 3-stage pipeline
<bart416>
swkhan, have you ever attempted to build an analog computer?
<swkhan>
i made some components of one like a differentiator, a summer, an integrator, etc.
<azonenberg>
lekernel: in the all-out configuration this thing is going to rival most of the 8-bit PICs i think
<azonenberg>
waay better cpu performance
<swkhan>
what constitutes an analog computer? i'm missing memory i guess...
<swkhan>
power efficiency?
<azonenberg>
not even close
<swkhan>
i see
<azonenberg>
but in price it would actually be comparable to some of the bigger 18Fs
<azonenberg>
You'd lose the analog peripherals of course, i dont have an ADC on the fpga :P
<azonenberg>
Its not cost effective if you are JUST running the softcore
<azonenberg>
what its useful for is if your design fills 3/4 of the fpga and you cram it in the other 1/4
<azonenberg>
rather than putting another chip on the board
<bart416>
My swkhan most of it is fairly easy to build actually
<bart416>
Putting it together is the hard part
<bart416>
At least in a way that can be somewhat "programmed"
<bart416>
Another guy here on freenode also named Bart is working on an analog-ish computer
<bart416>
Fully analog pong and tetris, lol
<berndj>
pong i can still get, but tetris? wow
<bart416>
He doesn't have any scopes so he has to wait until college starts again
<bart416>
He's going to the same-ish place I'm going to, heh
<bart416>
Well yeah, I go to a university technically, he goes to a college