<azonenberg>
i have no idea what that is in USD but its cheap :p
<bart416>
Used, but in good condition
<bart416>
Roughly 200 USD
<azonenberg>
i paid close to 1K USD for mine
<bart416>
Normally you'd pay over a tenfold of that for a new one
<azonenberg>
And that looks way better per channel
<azonenberg>
Mine has the 16ch LA which is nice, but deep memory would help greatly
<azonenberg>
for some applications
<bart416>
Well, logic analyzer you can build
<bart416>
Scope is a lot harder
<bart416>
An FPGA, USB chip, and some buffers and you have a LA
<azonenberg>
Yeah
<azonenberg>
I plan to do that soon actually
<azonenberg>
make one with really deep memory
<bart416>
Heh, I got to play with one of those newer NAs this week
<azonenberg>
Why do cheap scopes not have deep memory?
<azonenberg>
its not like ddr2 is expensive
<azonenberg>
you could throw a hundred megabytes on there for $10
<bart416>
most scopes use static ram as far as I know though azonenberg
<bart416>
well at least all the ones I've had to open up do so
<swkhan>
azonenberg_work: still no wafer. what did dhl/fedex say?
<azonenberg>
swkhan: it was us post office
<azonenberg>
and they say it was signed for
<azonenberg>
and delivered
<azonenberg>
you're saying it got lost? :(
<swkhan>
oh! okay, i'll check at the post office on monday then
<azonenberg>
you have the tracking #, right?
<swkhan>
i don't remember it. can you pm it to me?
<azonenberg>
sent
<swkhan>
they said it was delivered ~1 week ago?!
<azonenberg>
Yes
<azonenberg>
So somebody has it, apparnetly lol
<swkhan>
they did make a mistake recently. they gave us some highly flammable substance that "donna ...?" owns
<swkhan>
something dodecaethylthiol or something
<swkhan>
we haven't tried to contact donna because we're apathetic / lazy i guess =\
<azonenberg>
lol
<swkhan>
grr
<swkhan>
do you have much experience with a semiconductor parameter analyzer?
<azonenberg>
whats that? :P
<swkhan>
or a 4 point probe even?
<azonenberg>
I know the idea of a 4-point probe but i havent used thm
<swkhan>
it's a really fancy set of voltage sources and current sources and voltage monitors and current monitors
<azonenberg>
My sheet resistance measurements to date have been no more sophisticated than "is there something conductive on top of this insulating film or not?
<swkhan>
all i really need is an easy way to probe a really small metal insulator metal capacitor
<swkhan>
so i have it like a crossbar +
<azonenberg>
So you have two layers of metal with dielectric between them
<azonenberg>
Define small
<azonenberg>
50nm? 200um?
<swkhan>
larger =p
<azonenberg>
>200um?
<swkhan>
like maybe 500 um to 1 mm
<azonenberg>
oh
<azonenberg>
thats like, hand solderable
<azonenberg>
lol
<swkhan>
not with my hands :\
<azonenberg>
What do the pads look like?
<swkhan>
i don't have bond pads
<azonenberg>
how do you connect to the layers?
<azonenberg>
You dont have bond pads
<azonenberg>
so for the top layer you just probe the metal
<swkhan>
you type faster than i think
<azonenberg>
Is the bottom layer bigger?
<swkhan>
yes
<swkhan>
well they are at like a T junction
<azonenberg>
So you have two metal bars crossing at a T
<swkhan>
so i have the bottom electrode shadow mask patterned horizontally
<azonenberg>
the capacitor is where they overlap
<swkhan>
yes
<azonenberg>
And the 0.5mm figure is what exactly?
<azonenberg>
the width of one bar?
<swkhan>
the planar distance from where the bottom electrode is probed to where the top electrode is probed
<azonenberg>
Ok
<azonenberg>
So standard multimeter probes are a little big
<azonenberg>
You dont have proper micropositioners i take it?
<azonenberg>
If you did this'd be a solved problem
<swkhan>
we have some sort of positioners but either they don't work perfectly or i stink at using them or both
<swkhan>
we have tungsten probe tips that say 45 degree angle and 12 um which i assume is the tip width
<swkhan>
or tip radius or tip diameter
<azonenberg>
Ok
<azonenberg>
12um is plenty for this size
<azonenberg>
i've done large IC components with 25um probes
<swkhan>
well smaller is better. 0.5 mm is pathetic
<azonenberg>
lol
<swkhan>
but more important than all of that is some reproducible measurement
<azonenberg>
well I've hit 20um targets with homebrewed submicron probes
<swkhan>
the manipulators kind of bobble a bit when i lower or raise them
<swkhan>
wow!
<azonenberg>
and cheap micromanipulator 110 positioners
<swkhan>
110 dollars?
<azonenberg>
no, thats the model number
<azonenberg>
110 and 210
<swkhan>
oh
<azonenberg>
They were around $100 each on ebay though lol
<swkhan>
because ours were about 1000 each
<swkhan>
maybe 100
<azonenberg>
The $1K ones are overkill
<swkhan>
i just remember they weren't worth whatever we paid for them
<swkhan>
well how thick should a bond pad be by the way? how thick would your metal electrode (copper) be?
<azonenberg>
Hmm, depends on the bonding process
<azonenberg>
With copper its more annoying since you need a barrier layer
<azonenberg>
and adhesion
<swkhan>
i made mine ~100 nm each for top and electrode
<azonenberg>
100nm is fine if you are probing
<azonenberg>
i think
<swkhan>
i had an adhesion layer too
<azonenberg>
Ta? Cr?
<swkhan>
cr
<azonenberg>
ti?
<azonenberg>
Yeha, Cr is the de facto standard
<azonenberg>
thats what i use too
<azonenberg>
though i hear sputtered Ta is catching on
<swkhan>
but it takes forever to sputter all this stuff
<swkhan>
i was just talking to a professor about this yesterday =)
<azonenberg>
I do evaporation, a nice thick film only takes a few minutes once you have decent vacuum
<swkhan>
i was reading a book on electrodeposition
<swkhan>
and they said that nb and v give better adhesion layers than cr or ti
<azonenberg>
And like i said, thickness depends on the proces
<azonenberg>
for example if you are soldering to it (flip chip bonding) you want a micron ish
<azonenberg>
or it'll just dissolve into the solder
<azonenberg>
and yes, i've read a little about Nb and V
<azonenberg>
But they're pretty exotic
<azonenberg>
and not used because while they may be better, its not by much
<swkhan>
chromium can form quadruple bonds
<swkhan>
my mind is still blown
<swkhan>
i need to relax
<azonenberg>
Thats why it sticks so well
<azonenberg>
and i have homework to do but i dont want to :(
<swkhan>
i'm going to a film festival with some friends. i need to take my mind off research that doesn't work
<azonenberg>
Lol
<azonenberg>
I think i'm going to try one of my alternative hardmasking ideas
<swkhan>
i'd invite you, but you'd have to take a plane... =p
<azonenberg>
One that i came up with a long time ago but never tried
<azonenberg>
i even have the coated wafer, just need to actually etch
<azonenberg>
and lol
<azonenberg>
Yeah, kinda on the wrong side of the continent :p
<swkhan>
the chromium mask?
<azonenberg>
no
<azonenberg>
The Cr mask has to wait until i get up to campus next week to do the thick Cr film
<azonenberg>
This one is older but i never actually tested
<azonenberg>
Ta2O5 plus Cu:Cr stack
<azonenberg>
use the metal as a mask for HF etch of the oxide
<azonenberg>
then use the oxide as a mask for KOH of the silicon
<azonenberg>
i have the three-film wafer sitting on a shelf but never actualy did anythign with it
<swkhan>
i'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 go
<swkhan>
honestly, if i don't find it in a week, i'm just going to use one our spares and thermally grow the oxide in atmosphere