<B0101>
i was thinking about making a mini clean room, in a box
<azonenberg>
You mean a glove box?
<azonenberg>
Yeah, entirely feasible
<azonenberg>
Building one is on my to-do list too, for certain critical operations
<azonenberg>
for example wafer clean followed by spin coating
<B0101>
similar to a glove box, but this time, they can be detached/attached to a process machine...
<azonenberg>
You mean a sealed container for carrying between tools?
<azonenberg>
Yeah, thats doable too
<B0101>
yes
<B0101>
tell me when my ideas get crazy though
<azonenberg>
What you're descriibng is SOP for most modern fabs
<azonenberg>
the cleanrooms are like class 1000 and the tools are all sealed and filtered to below class 1
<azonenberg>
nobody ever handles the wafers, they're moved by robot between tools in sealed boxes
<azonenberg>
Basically, around 10 years or so ago
<azonenberg>
Somebody finally realized that humans are dirty
<azonenberg>
and putting them in a clean environment isnt the best idea
<azonenberg>
So now the outer "container" cleanroom is only used for servicing etc
<azonenberg>
and the tools themselves do all of the interesting stuff
<azonenberg>
So what are your crazy ideas?
<B0101>
hmm, well I ws thinking about getting to 45nm scale (really crazy idea though)
<azonenberg>
lol that *is* crazy :p
<azonenberg>
Not saying impossible, very little is
<azonenberg>
But it will be far from easy lol
<azonenberg>
For prototype-scale volumes your best bet would probably be e-beam direct write
<azonenberg>
forget about masks
<azonenberg>
build yourself a SEM and then make a direct-write module
<azonenberg>
I suggest you set a more reachable goal first
<azonenberg>
and see how feasible that is
<azonenberg>
say, 500nm
<azonenberg>
then 180
<azonenberg>
I mean, certainly doing this kind of stuff on the prototype scale will be easier than mass production
<azonenberg>
but by how much?
<azonenberg>
I intend to start out by building a nice contact aligner
<horizontally>
build yourself a SEM.. azonenberg is one of the few people i know who could probably build it (and somehow acquire a diffusion pump from the lab manager) in his spare time
<azonenberg>
That will let me hit 12.5 um design rules with professionally made film masks (laserlab.com)
<horizontally>
what do you think of photosciences?
<azonenberg>
are they a mask shop?
<horizontally>
yeah
<azonenberg>
Never heard of them, photronics is the only other one i know of besides laserlab
<horizontally>
i was told about photosciences from our lab manager
<azonenberg>
Anyway so that'd be a temporary step though
<azonenberg>
The next step is to build my own laser direct write rig ;p
<azonenberg>
So i can make my own chrome-on-glass masks
<azonenberg>
Then the most involved tool (on the lithography front at least) would be an H-line stepper
<azonenberg>
probably 4x reduction of a 12.5um design rule mask
<horizontally>
why do you want to make stuff so small?
<horizontally>
what is your intended goal from there?
<horizontally>
sure it's nice and all
<azonenberg>
would put me at a 3.125um design rule
<azonenberg>
horizontally: a) have fun
<horizontally>
sure
<azonenberg>
b) advance the state of the art in low-budget fab
<azonenberg>
to the point that a 350nm fab is something you could have in every high school science classroom
<horizontally>
wow, sure, cool
<azonenberg>
Thats really the idea, there is not enough people getting into nanotech and having it available might help
<azonenberg>
Also, just the coolness factor of being able to, say, design a custom ASIC instead of using a CPLD for some glue logic :p
<azonenberg>
imagine having a little project with a PIC and a homemade MEMS accelerometer in a flip-chip BGA package
<azonenberg>
FCBGA is how i plan to package all of my stuff, actually
<azonenberg>
because it means i dont need to wirebond
<azonenberg>
just put the chip on a hot plate, heat to melting point of solder
<B0101>
brb
<azonenberg>
and under a 30x stero microscope use fine tweezers to place a solder ball on each bond pad
<azonenberg>
then cool
<azonenberg>
flip over, put on PCB, and put board in oven to reflow
<horizontally>
i don't know much about packaging
<horizontally>
how did you learn about it?
<azonenberg>
this would basically be a chip scale BGA
<horizontally>
i have a pcb design book i haven't read through yet either
<azonenberg>
a) look at premade chips and study them from the outside
<horizontally>
though it's meant for orcad
<azonenberg>
b) reverse engineering
<horizontally>
oh jesus, the long road
<azonenberg>
decapping premade chips and studying how things fit together
<azonenberg>
plus various reading on wiki etc
<azonenberg>
but once you actually look at a DIP that you've dissolved the plastic from
<azonenberg>
and see how everything fits together
<azonenberg>
it all makes sense
<horizontally>
how do you dissolve the plastic but not the chip inside?
<horizontally>
so there's a bit of wirebonding
<azonenberg>
Hot nitric acid is the SOP
<horizontally>
and some polymer container
<horizontally>
nitric acid really? wow
<azonenberg>
it eats organic mateirals but not silicon, glass, or gold
<azonenberg>
the chip is usually passivated with SiO2 and has gold bond wires
<azonenberg>
Though if you arent careful it will eat the tin-plated copper legs
<azonenberg>
but the die itself survives with no problem
<azonenberg>
The cheap option is to just throw the whole chip into a beaker of sulfuric
<azonenberg>
and cook for a while
<azonenberg>
less selective but if you want a bare die to study its fine
<azonenberg>
You can do that method with nitric too
<azonenberg>
In either case, you will want a fume hood or to be working outside
<horizontally>
i got nitric and sulfuric
<horizontally>
i'll try nitric soon
<horizontally>
that sounds cool
<azonenberg>
Hot acid vapor is somewhat unpleasant
<horizontally>
yeah i've smelt it before
<azonenberg>
if you think the fumes are bad at room temp try at 150C