M
Meat Plow
Guest
On Fri, 18 Sep 2009 14:36:45 +0100, "N_Cook" <diverse@tcp.co.uk>wrote:
mentioned. Lead inhibits the growth of whiskers they say.
Anyways, seems that a satellite responsible for paging went down due
to whiskers a little while back. Supposedly caused quite the ruckus
here on Earth. And that some scientists in aerospace are very worried
about whiskers. Imagine some nuclear arms or even conventional
explosives fitted with lead free electronics and the newer military
and civilian aircraft electronics that are lead free.
Watched a special on the telly the other night where lead free wasMeat Plow <meat@petitmorte.net> wrote in message
news:34sldg.1h4.17.16@news.alt.net...
On Thu, 17 Sep 2009 13:57:50 +0100, "N_Cook" <diverse@tcp.co.uk>wrote:
and why?
I recently saw some printed advertising copy, including this statement
concerning BGA chips
"We safely remove the existing lead-free solder balls and replace them
with
SnPb "
cannot find reference to that on their site, just
http://www.retronix.com/Bga_reballing
BGA Reballing (Lead Free / 63-37 / High Melt Ceramic Packages)
$1/2 million investment in a unique technology has allowed Retronix to
reball BGA and uBGA devices without inducing a thermal cycle (mass
reflow),
which can damage the integrity of the device. We use a laser energy pulse
which attaches the solder spheres individually to the pad in less than
20m/s. The bonding of the sphere to pad in this short time does not allow
heat dissipation into the silicon die, therefore offering a safe
alternative
to mass reflow. The equipment shown is contained within a clean room
environment, supplemented by laminar flow hoods and a nitrogen chamber
for
the reballing process. We can process sphere sizes from 760 microns down
to
100 microns.
Anyone who is concerned about tin whiskers?
I thought one of the advantages of using the BGA format was to avoid closely
spaced tin-whisker-liable interconnect pinning/traces.
mentioned. Lead inhibits the growth of whiskers they say.
Anyways, seems that a satellite responsible for paging went down due
to whiskers a little while back. Supposedly caused quite the ruckus
here on Earth. And that some scientists in aerospace are very worried
about whiskers. Imagine some nuclear arms or even conventional
explosives fitted with lead free electronics and the newer military
and civilian aircraft electronics that are lead free.