whitequark changed the topic of #tinyqma to: design of an open hardware DDS-based QMA with a low-voltage dc/rf stage :: http://irclog.whitequark.org/tinyqma
<mne>
whitequark, that depends on the thickness of the nitride layer
<mne>
There are even tables for that providing an overview of color vs thickness
<mne>
:)
<whitequark>
nitride?
<whitequark>
layer?
<whitequark>
I'm talking about the color of the liquid
<mne>
ooh, ok. In that sense no2 makes more sense :) So you're boiling them in hno3 :)
<whitequark>
yea
<mne>
is it working well ? what concentration do you use ?
<whitequark>
"concentrated"
<whitequark>
let me see the datasheet
<mne>
that wold be ~ 70%
<whitequark>
hm don't have it
<whitequark>
but yes
<whitequark>
about seventy
<whitequark>
still need to boil for quiiiite a while
<whitequark>
like 20-30 min
<mne>
And that works well to dissolve the epoxy ? I suppose you need to heat i up so that it starts to work at all ?
<whitequark>
yes
<mne>
right
<whitequark>
it doesn't dissolve it entirely
<whitequark>
it makes the outer layers fall off like flakes
<whitequark>
and exposing the IC itself, around which the epoxy is harder or something
<whitequark>
if you boil it long enough, that epoxy will also come off with gentle swab movement
<whitequark>
and you will be left with a very clean surface
<mne>
H2SO4 dissolves it completely, but you need to heat it up to ~ 150 °C at leats
<whitequark>
can't get H2SO4
<whitequark>
easily
<whitequark>
"OMGDRUGS"
<mne>
hmm, ok
<whitequark>
nitric is freely sold tho
<mne>
For bulk decapsulations I typically use H2SO4 whereas otherwise I use fuming nitric. That works really well
<mne>
Do these flakes also come off well in an ultrasonic acetone bath ?
<whitequark>
eh my ultrasonic bath is made of plastic
<whitequark>
not recommended to use with acetone
<mne>
use a glass beaker with the acetone in it
<whitequark>
hrm
<whitequark>
yeah
<whitequark>
don't see the point though
<whitequark>
I need to fix the chip on a slide anyway
<mne>
the use is cleaning. If you get really nice and clean results without it, you're fine ;)