[SI-LIST] Re: ROHS
- From: Conrad M Herse <herse@xxxxxxxxxxxxxxxxxx>
- To: ldieguez@xxxxxxxxxx
- Date: Fri, 20 Apr 2007 11:08:06 -0500
This was recently forwarded to me by a colleague.
Conrad Herse
herse@xxxxxxxxxxxxxxxxxx
On 04/20/07 11:01, Leonard Dieguez wrote:
> A quick poll / question: Has anyone recently had problems relating to
> tin whiskers from the non-leaded solder?
>
>
> Leonard Dieguez
>
>
>
>
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From: "Dr. Howard Johnson" <howie03@xxxxxxxxxx>
To: <hsdd@xxxxxxxxxxxxx>
Subject: [hsdd] High-Speed Digital Design Newsletter - - Rollback the
Lead-Free Initiative -
Date: Wed, 18 Apr 2007 00:04:26 +0000
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<P> </P>
<P><FONT style=3D"FONT-WEIGHT: 700; FONT-SIZE: 16pt" =
face=3DArial=20
color=3D#ff0000>Rollback the Lead-Free=20
Initiative</FONT></P><B><SPAN=20
style=3D"FONT-SIZE: 10pt; COLOR: red; FONT-FAMILY: =
Arial">Twelve=20
Myths about RoHS</SPAN></B><FONT face=3DArial =
color=3D#ff0000=20
size=3D4><B>
<P><FONT color=3D#000000 size=3D2>HIGH-SPEED DIGITAL=20
DESIGN — online =
newsletter =20
—<BR>Vol. 10 Issue 01</FONT></B></P>
<P><!-------------------------- INSERT CONTENT HERE =
-------------------------->
<P>
<P><FONT face=3DVerdana color=3D#000000 size=3D2>If it =
has been=20
awhile since my last correspondence, my only excuse is =
that=20
I've been busy working on a new course, titled: =
"High-Speed=20
Noise and Grounding". At this point the marketing =
gurus here=20
are not sure whether the course will be released in =
book=20
format or DVD format, but whatever happens we will =
announce it=20
through this newsletter when available. </P>
<P class=3DMsoBodyText>Today's letter has to do with =
one of the=20
important <I>system reliability</I> topics I include =
in that=20
course.</P>
<HR>
</FONT></FONT><FONT face=3DArial color=3D#ff0000>
<P class=3DMsoBodyText><B><SPAN=20
style=3D"COLOR: red; FONT-FAMILY: Arial">Rollback the =
Lead-Free=20
Initiative</SPAN></B></P></FONT><FONT face=3DArial =
color=3D#ff0000=20
size=3D4><FONT face=3DVerdana color=3D#000000 =
size=3D2>
<P class=3DMsoBodyText>I'm no expert in manufacturing=20
technology, but I can smell trouble coming a mile =
away. I=20
believe that our industry, having jumped onto the =
lead-free=20
bandwagon, is headed towards a train wreck of immense=20
proportions. Please tell your management.</P>
<P class=3DMsoBodyText>I'm sure you've all heard about =
the=20
recent EU legislation called RoHS (Restriction of =
Hazardous=20
Substances). As of July of 2006, RoHS legislation =
precludes=20
the use of lead in electronic products destined for =
sale in=20
Europe with few exceptions. The primary motivations =
for this=20
legislation were environmental concerns. </P>
<P class=3DMsoBodyText>The RoHS legislation affects =
component=20
lead plating as well as solder and solder paste. The=20
legislation was developed, I believe, under the =
misconception=20
that the switch from a tin-lead solder chemistry to =
pure tin=20
would be painful, but technologically possible. The=20
legislators incorrectly assumed that the only =
difference=20
between tin-lead solder and pure tin solder was the =
melting=20
point. </P>
<P class=3DMsoBodyText>Prior to 2006, most electronic =
components=20
were coated with lead-based solder, 63% Sn, 37% Pb, =
popularly=20
called 63/37 solder. Manufacturers use that particular =
proportion because it has the lowest melting =
temperature of=20
any Sn-Pb mixture (i.e., it is the <I>Eutectic</I> =
mixture).=20
It makes a good, strong solder joint. </P>
<P class=3DMsoBodyText>As a result of RoHS =
legislation, many=20
component manufacturers have begun supplying parts =
with a=20
lead-free plating made from ordinary tin. In many =
cases the=20
old 63/37 solder coated products may no longer be=20
available.</P>
<P class=3DMsoBodyText>Replacing tin-lead with pure =
tin is=20
turning out to have been a huge mistake. There are two =
significant differences between lead-free assembly and =
lead-based assembly. </P>
<P class=3DMsoBodyText>(1) Lead-free assembly is not =
better for=20
the environment, it is worse. The additional tin =
mining=20
required to produce high-purity tin alloys, plus the =
mining of=20
other precious metals required to alloy with tin in=20
substitution for lead is a poor trade for the use of =
existing=20
lead, much of which comes from recycled products. This =
information comes from a study conducted by the U.S.=20
Environmental Protection Agency (EPA). The study =
undercuts the primary basis for RoHS.</P>
<P class=3DMsoBodyText>(2) Lead-free assembly is less =
reliable=20
than lead-based assembly. The E.U. environmental =
commission=20
admits this point. That's why they grant exceptions =
for=20
military and high-reliability applications that still =
use SnPb=20
solder. </P>
<P class=3DMsoBodyText>I'm all for environmental =
legislation=20
when it actually helps. When it doesn't help, and it =
harms=20
something else, I question the result. </P>
<P class=3DMsoBodyText>What harm is being done? Let's =
start with=20
tin whiskers. The electronics industry has discovered=20
(re-discovered, actually, as this knowledge is quite =
old) that=20
typical "bright" tin plating grows prodigious numbers =
of tin=20
whiskers in a short amount of time. A tin-lead =
Eutectic=20
mixture does not grown whiskers. Something about the =
lead=20
prevents their formation. </P>
<P class=3DMsoBodyText>Tin whiskers are small, =
unbelievably thin=20
metallic hair-like growths that naturally emerge from =
the=20
surface of solid tin (Sn). On lead-free tin surfaces, =
tin=20
whiskers may grow to a length sufficient to short one=20
electronic circuit to another, creating product =
failure. </P>
<P class=3DMsoBodyText>Material scientists attribute =
whisker=20
growth in ordinary bright tin to various impurities =
within the=20
tin. Purifying the tin-plating solution changes the =
character=20
of the finished item. Instead of a bright tin finish =
you get a=20
"matte" finish. This step helps reduce but does not =
eliminate=20
the number of whiskers. Some people believe that matte =
plating=20
fixes the problem. I don't think so. </P>
<P class=3DMsoBodyText>Figure 1 shows a young tin =
whisker=20
growing straight out of a matte tin finish. This =
picture comes=20
from Wan Zhangz and Felix Schwager, "Effects of Lead =
on Tin=20
Whisker Elimination", J. Electrochem. Soc., 153 (5) =
C337-C343=20
(2006). This particular whisker was grown at ambient=20
temperature under normal storage conditions. No =
electric=20
currents are required to form whiskers. The growth is=20
spontaneous. A matte tin finish certainly works better =
than a=20
bright tin finish, but does not, in my opinion, fix =
the=20
problem. Lead does.</P>
<P><IMG height=3D465=20
src=3D"http://www.sigcon.com/images/news/v10_01a.jpg"; =
width=3D663=20
border=3D0></P>
<P class=3DMsoBodyText><B>Fig 1</B>—<I>Tin =
whiskers growing on=20
electrodeposited matte tin at ambient temperature =
[Zhangz and=20
Schwager].</I></P>
<P class=3DMsoBodyText>You may be looking at Figure 1 =
thinking,=20
"Hey, that whisker is only about 16 <I>microns</I> =
long (less=20
than one thousandth of an inch), not long enough to do =
any=20
damage." If whiskers grew no longer than one =
thousandth, I=20
would agree. Unfortunately, they get longer. </P>
<P class=3DMsoBodyText>Figure 2 shows the dramatic =
growth that=20
can happen under some circumstances. This picture is =
not for=20
the faint of heart. <A=20
href=3D"http://www.sigcon.com/Pubs/news/10_01A.htm"=20
target=3D_top>Click here to view</A>. Whiskers =
can easily=20
exceed 1 mm -- yes, that's 1,000 microns, and in some =
cases=20
even as much as 10 mm. </P>
<P class=3DMsoBodyText>I bring all this up because I =
recently=20
toured a number of military electronics facilities. In =
discussions with engineers at those locations they all =
agreed=20
that a matte tin finish is not sufficient to render =
their=20
products suitably reliable. They have uniformly =
shunned the=20
use of tin-plated hardware of any kind. Fortunately, =
military=20
products get a special exemption from RoHS. They can =
use as=20
much lead as they want. The exemption was granted on =
the basis=20
that the E.U. commission understands quite clearly =
that <I>no=20
suitably reliable substitute for lead-based solders =
has yet=20
been found</I>. </P>
<P>Great, so the E.U. admits there is no reliable =
substitute.=20
Yet, they require use of a substitute. </P>
<P class=3DMsoBodyText>Is this some kind of plan to =
increase=20
sales of electronic gadgets? Is this a way to make =
sure that=20
products fail quickly, so consumers have to buy more? =
</P>
<P class=3DMsoBodyText>We won't know for several years =
how=20
severe the problem will ultimately become, but what we =
do know=20
is that many tin-whisker failures have already =
happened, and=20
more will happen in the future. </P>
<P class=3DMsoBodyText>Already happened? Yes. 17 =
April, 2005 —=20
Millstone Nuclear Generating Station — A single =
tin whisker=20
created a bridge (short circuit) between a diode and =
the=20
output trace on a circuit card, causing a partial =
reactor=20
shutdown. P. Daddona, "<A=20
style=3D"COLOR: blue; TEXT-DECORATION: underline; =
text-underline: single"=20
=
href=3D"http://nepp.nasa.gov/whisker/reference/tech_papers/2005-dadonna-n=
uclear-reactor-shutdown.pdf"><SPAN=20
style=3D"COLOR: windowtext; TEXT-DECORATION: =
none">Reactor=20
Shutdown: Dominion Learns Big Lesson from a Tiny Tin=20
Whisker</SPAN></A>", <A=20
style=3D"COLOR: blue; TEXT-DECORATION: underline; =
text-underline: single"=20
href=3D"http://www.theday.com/";><SPAN=20
style=3D"COLOR: windowtext; TEXT-DECORATION: none">The =
Day</SPAN></A> (New London, CT), July 4, 2005 <BR><A=20
style=3D"COLOR: blue; TEXT-DECORATION: underline; =
text-underline: single"=20
=
href=3D"http://nepp.nasa.gov/whisker/reference/tech_papers/2005-dadonna-n=
uclear-reactor-shutdown.pdf"=20
=
target=3D_blank>http://nepp.nasa.gov/whisker/reference/tech_papers/2005-d=
adonna-nuclear-reactor-shutdown.pdf</A>=20
</P>
<P class=3DMsoBodyText>Environmentalists who favor =
restriction=20
of lead in electronic circuits point out that the =
reactor=20
didn't actually explode, and that we shouldn't have =
nuclear=20
reactors, anyway. I don't find that response very=20
satisfying.</P>
<P class=3DMsoBodyText>Just in case you get into a =
debate about=20
lead-free solder, here are some myths I've encountered =
during=20
my research.</P>
<P class=3DMsoBodyText>Myth #1. <I>Tin</I> <I>Whiskers =
only grow=20
in space. </I>Not true. A lot of research in the =
period=20
2002-2006 was conducted by aerospace companies using a =
vacuum=20
environment for their experiments. This created a =
perception=20
that it is only a "space" problem. Actually, whiskers =
can and=20
do happen everywhere. The whiskers in Figure 1 grew at =
ambient=20
temperature and humidity. </P>
<P class=3DMsoBodyText>Myth #2. <I>Tin Whiskers only =
grow in=20
temperature-cycling environments.</I> Not true. They =
grow=20
under ambient conditions. Accelerated life-cycle =
testing is=20
carried out per JESD201 using temperature cycling, as =
that=20
seems to exacerbate the growth, but at the time =
JESD201 was=20
written no one knows the correlation between the =
accelerated=20
tests and what will really happen over time.</P>
<P class=3DMsoBodyText>Myth #3. <I>Conformal coating =
stops=20
whisker growth.</I> Good idea, but it doesn't work. =
The tip of=20
a whisker is sharp down to atomic dimensions. It pokes =
right=20
through a conformal coating. No coating has yet been =
found=20
that is immune, although there is some recent hope for =
a new=20
low-modulus polyurethane material. <SPAN=20
style=3D"FONT-FAMILY: Arial">"</SPAN><A=20
style=3D"COLOR: blue; TEXT-DECORATION: underline; =
text-underline: single"=20
=
href=3D"http://nepp.nasa.gov/whisker/reference/tech_papers/2006-Woodrow-C=
onformal-Coating-PartII.pdf"><SPAN=20
style=3D"COLOR: windowtext; TEXT-DECORATION: =
none">Evaluation of=20
Conformal Coatings as a Tin Whisker Mitigation =
Strategy, Part=20
2"</SPAN></A>, T. Woodrow, SMTAI, Sept. 2006 <BR><A=20
style=3D"COLOR: blue; TEXT-DECORATION: underline; =
text-underline: single"=20
=
href=3D"http://nepp.nasa.gov/whisker/reference/tech_papers/2006-Woodrow-C=
onformal-Coating-PartII.pdf"=20
=
target=3D_blank>http://nepp.nasa.gov/whisker/reference/tech_papers/2006-W=
oodrow-Conformal-Coating-PartII.pdf</A>=20
</P>
<P class=3DMsoBodyText>Myth #4. <I>Whiskers don't =
happen very=20
often. </I><SPAN=20
style=3D"BACKGROUND-POSITION: 0% 0%; =
BACKGROUND-ATTACHMENT: scroll; BACKGROUND-IMAGE: url(none); =
BACKGROUND-REPEAT: repeat"><A=20
href=3D"http://nepp.nasa.gov/whisker/failures/";><FONT=20
color=3D#0000ff>Check out this list of hair-raising=20
examples</FONT></A></SPAN> of tin-whisker failure in=20
satellites, airplanes, medical, industrial and =
computer=20
equipment. Engineers are now just beginning to =
recognize a lot=20
of past failures as having been caused by tin =
whiskers.</P>
<P class=3DMsoBodyText>Myth #5. <I>A whisker is too =
small to=20
short out anything important.</I> That is true for =
some=20
classes of high-voltage, high-power equipment. An =
individual=20
whisker conveys only about 30 mA. In an AC power =
environment,=20
the whisker would quickly burn out. In digital =
electronics,=20
however, 30 mA is more than enough to cause serious =
havoc.=20
</P>
<P class=3DMsoBodyText>Myth #6. <I>A better solder is =
just=20
around the corner.</I> I don't believe it. The =
industry has=20
tried all sorts of additives from Antimony to Zinc and =
nothing=20
works like Lead. The 63/37 mixture is very =
soft—that seems to=20
be part of the magic. It doesn't accumulate stress, it =
merely=20
deforms. Even if we had a better solder, unless it =
completely=20
coats all exposed portions of every component lead, =
any=20
exposed tin-plated leads remain subject to =
whiskering.</P>
<P class=3DMsoBodyText>Myth #7. <I>The solution is SAC =
solder.</I> The "SAC" solder mixture is made =
from Tin,=20
Silver, and Copper. The silver and copper additives =
suppress=20
tin whisker growth, but it remains unclear whether =
they=20
completely inhibit whisker growth over a long period =
of time.=20
Military and other high-reliability products don't use =
SAC.=20
They use only SnPb. In addition, SAC solder creates =
other=20
problems.=20
<P>For example, SAC solder requires a different =
soldering=20
temperature profile than that used for Tin-Lead =
solder. If you=20
mix SAC-based solder with non SAC-based coatings, the =
results=20
can be very poor, so you must ensure that <I>all</I> =
your=20
components use the SAC mixture. Yet, looking at two =
parts only=20
a metallurgist can tell the difference between a =
lead-based=20
lead coating and a SAC-based lead-free coating. =
Substantial=20
possibility of error exists.<BR><A=20
style=3D"COLOR: blue; TEXT-DECORATION: underline; =
text-underline: single"=20
=
href=3D"http://thor.inemi.org/webdownload/projects/ese/HighReliability_Ro=
HS/High_Rel_position_061206.pdf"=20
=
target=3D_blank>http://thor.inemi.org/webdownload/projects/ese/HighReliab=
ility_RoHS/=20
High_Rel_position_061206.pdf </A></P>
<P class=3DMsoNormal>Harvey Miller at <A=20
style=3D"COLOR: blue; TEXT-DECORATION: underline; =
text-underline: single"=20
href=3D"http://fabfileonline.com/"=20
target=3D_blank>http://fabfileonline.com/</A> =
has this to=20
say about the use of SAC-based solder: "Without =
the=20
softening effect of lead, the SAC alloys are more =
brittle and=20
more likely to crack under pressure. They don't =
wet=20
well, requiring more active fluxes. They don't =
have a=20
sharp eutectic, staying plastic over a larger range, =
allowing=20
intermetallics to form and leading to voids. =
Their=20
higher melting temperatures stress laminates and =
components,=20
limiting choices and narrowing process windows. There =
are=20
unpredictable long-term degradation mechanisms such =
as: 1) the=20
Kirkendall Effect, in which copper migrates into tin, =
leaving=20
voids, 2) tin whisker formation, and 3) tin pest, in =
which the=20
tin turns into powder. "</P>
<P class=3DMsoBodyText>Finally, regarding SAC, here's =
a=20
testimonial letter submitted by John Anderson to the =
Ron Lasky=20
forum: "<SPAN lang=3DEN>I have to repair industrial =
control=20
equipment, and so far there has been a really poor =
track=20
record with lead-free solder. Mind you, the products I =
repair=20
and design are almost always wet, cold, hot and =
vibrating and=20
tin-lead solder is far superior to the lead-free =
assembly=20
processes in every respect for extreme applications. =
Not only=20
are tin whiskers a headache, but embrittlement =
problems cause=20
thousands of hours of troubleshooting time searching =
for=20
intermittent, hairline-cracked joints that we just =
don't see,=20
or very rarely see with tin-lead solder. At this =
point,=20
several industrial clients of mine are insisting on =
non-RoHS=20
assembly (RoHS parts are <SPAN class=3Dcaps>OK, =
</SPAN>just not=20
the assembly process) of all components used on =
assembly=20
equipment and control systems…" </SPAN><A=20
style=3D"COLOR: blue; TEXT-DECORATION: underline; =
text-underline: single"=20
=
href=3D"http://www.indium.com/drlasky/entry.php?id=3D476"=20
=
target=3D_blank>http://www.indium.com/drlasky/entry.php?id=3D476</A></P>
<P class=3DMsoBodyText>Myth #8. <I>Eliminating lead =
from solder=20
saves the environment.</I> According to John =
Burke, <A=20
style=3D"COLOR: blue; TEXT-DECORATION: underline; =
text-underline: single"=20
href=3D"http://www.rohsusa.com/"=20
target=3D_blank>http://www.rohsusa.com/</A>, the US=20
Environmental protection agency "Report on Solders in=20
Electronics: A Life-Cycle Assessment" (472 pages) =
published=20
August 2005 shows that the replacement for =
“leaded” solder=20
generally referred to as “SAC alloy” has a =
<I>greater</I>=20
impact on the environment than tin lead solder in a =
number of=20
areas such as non-renewable resource use, energy use, =
global=20
warming, ozone depletion, and water quality. =
Admittedly,=20
leaded solder performs worse on issues of toxicity, =
mainly to=20
workers who handle the material. Manufacturers can =
(and have=20
already for the past 60 years) addressed the toxicity =
issue=20
for workers by using exhaust hoods, wearing gloves, =
and=20
washing hands. My conclusion? SAC solder is markedly =
worse for=20
the environment than lead-based solder. <I>We are not =
saving=20
the environment by moving to SAC solder, we are =
damaging=20
it.</I> Here is a link to the full report: <BR><A=20
style=3D"COLOR: blue; TEXT-DECORATION: underline; =
text-underline: single"=20
=
href=3D"http://www.epa.gov/opptintr/dfe/pubs/solder/lca/index.htm"=20
=
target=3D_blank>http://www.epa.gov/opptintr/dfe/pubs/solder/lca/index.htm=
</A>=20
</P>
<P class=3DMsoBodyText>Myth #9. <I>Lead leaches out of =
landfills=20
into the groundwater.</I> True for paint and gasoline, =
but not=20
necessarily for pcb assemblies. Lead in a pcb assembly =
exists=20
in a solid form that does not migrate like paint or =
gasoline.=20
</P>
<P class=3DMsoBodyText>Myth #10. <I>Long-term =
reliability=20
doesn't matter for consumer electronics.</I> Try =
telling this=20
to Swatch, the Swiss watch-maker. They were early =
adopters of=20
the lead-free movement. After discovering hideous =
difficulties=20
with tin whiskers, they ended up shutting down =
production for=20
some months while they changed back to 63/37 solder. =
In the=20
process, they helped push through a RoHS exemption for =
fine-pitch pcb circuitry. </P>
<P class=3DMsoBodyText>Myth #11. <I>Whiskers can't =
short between=20
balls on a 1-mm component.</I> This came from studies=20
referenced by Swatch in their application for =
exemption.=20
Swatch was seeking some kind of rule they could use to =
exempt=20
themselves without raising the issue for everyone. =
They found=20
some research support for the idea that whiskers don't =
grow=20
beyond 800 microns. Based on that, they postulated =
that a 650=20
micron pitch was unsafe, and should be exempted, but =
800=20
microns was fine and didn't need exemption. Now you go =
look at=20
the picture in Fig. 2 and tell me that there is a hard =
upper=20
limit on whisker length. I don't think so. </P>
<P class=3DMsoBodyText>Myth #12. <I>You are exempt =
from=20
regulation.</I> Not true. Some components will arrive =
at your=20
factory door with 63/37 solder surfaces, some with =
SAC, and=20
some with pure tin. You have to deal with the issue =
whether or=20
not you sell products in Europe. </P>
<P class=3DMsoBodyText>The RoHS committee has now =
granted=20
exemptions for military equipment, some classes of=20
high-reliability telecommunications equipment, and =
fine-pitch=20
(less than 0.65 mm pitch) circuitry. These exemptions =
create=20
an historic opportunity to roll back the RoHS =
legislation as=20
it applies to all electronic printed wiring board =
assemblies.=20
If you want to push back against the lead-free =
legislation,=20
please go here, sign up for information, and write to =
Mr.=20
Burke expressing your support: </P>
<P class=3DMsoBodyText>John Burke, "Push Back" =
(<A=20
style=3D"COLOR: blue; TEXT-DECORATION: underline; =
text-underline: single"=20
href=3D"http://www.rohsusa.com/";><SPAN=20
style=3D"COLOR: windowtext; TEXT-DECORATION: none"><A=20
style=3D"COLOR: blue; TEXT-DECORATION: underline; =
text-underline: single"=20
href=3D"http://www.rohsusa.com/"=20
=
target=3D_blank>http://www.rohsusa.com/</A></SPAN></A><FONT=20
color=3D#000000><SPAN>)</SPAN></FONT></P>
<P class=3DMsoBodyText>If there is any progress on the =
issue I=20
hope to report on it at my upcoming seminars in =
Boston, MA,=20
May 7-10, 2007. Although the main subjects of those =
seminars=20
will be "<A=20
=
href=3D"http://www.sigcon.com/seminars/seminarHSDD.htm";>High-Speed=20
Digital Design</A>" and "<A=20
=
href=3D"http://www.sigcon.com/seminars/seminarAHSSP.htm";>High-Speed=20
Signal Propagation</A>", I am always happy to respond =
to=20
questions on any topic, especially during lunch and =
breaks.=20
</P>
<P class=3DMsoClosing>Best Regards,<BR>Dr. Howard =
Johnson</P>
<P class=3DMsoClosing>P.S. I am still collecting =
data on=20
this topic. If you have any additional information or=20
anecdotes you'd like to relate, please email me at <A=20
href=3D"mailto:howie03@xxxxxxxxxx?subject=3DRe: Tin =
Whiskers">howie03@xxxxxxxxxx</A></P>
<HR>
<P class=3DMsoBodyText>For more fascinating =
information on the=20
topic of tin whiskers:</P>
<P class=3DMsoNormal>NASA Goddard Space Flight Center =
Basic=20
Info/FAQ<BR><A=20
=
href=3D"http://nepp.nasa.gov/whisker/";>http://nepp.nasa.gov/whisker/</A><=
/P>
<P class=3DMsoNormal>University of Maryland Center for =
Advanced=20
Life-Cycle Engineering (CALCE)<BR><A=20
=
href=3D"http://www.calce.umd.edu/lead-free/";>http://www.calce.umd.edu/lea=
d-free/</A></P>
<P class=3DMsoNormal>Robotic Solder Dipping Replaces =
Pure Tin=20
With a Tin-Lead Finish<BR><A=20
=
href=3D"http://www.bmpcoe.org/";>http://www.bmpcoe.org/</A></P>
<P class=3DMsoNormal>“Tin Whiskers: A New DMSMS =
Issue,” DMSMS=20
COE Newsletter, Vol<BR>3, Issue 3, April 2005 <BR><A=20
=
href=3D"http://www.dmsms.org/";>http://www.dmsms.org/</A></P>
<P class=3DMsoNormal>A litany of woes…<BR><A=20
=
href=3D"http://www.leadfree.org/RoHS_3-2-2.asp";>http://www.leadfree.org/R=
oHS_3-2-2.asp</A></P>
<HR>
<FONT face=3DArial color=3D#800080 size=3D4></FONT>
<P></P></FONT></FONT>
<TABLE style=3D"BORDER-COLLAPSE: collapse" =
borderColor=3D#111111=20
cellSpacing=3D0 cellPadding=3D0 width=3D"100%" =
bgColor=3D#ffff99=20
border=3D1>
<TBODY>
<TR>
<TD width=3D"100%"><FONT face=3DArial =
color=3D#800080 size=3D4>
<P align=3Dcenter><SPAN=20
style=3D"TEXT-DECORATION: =
overline"><B><BR><BR>Dr.=20
Johnson's final spring 2007 seminar=20
=
<U><BR></U></B></SPAN><U><B> &nb=
sp; =20
is just a few weeks=20
=
away &nb=
sp; =20
</B></U></P>
<P class=3Dbodytxt =
align=3Dcenter> </P></FONT><FONT=20
face=3DArial color=3D#800080>
<P align=3Dcenter><B><I><FONT =
size=3D4>High-Speed Digital=20
Design<BR> and <BR>Advanced High-Speed =
Signal=20
Propagation<BR></FONT><BR></I></B>in Boston, =
MA</P>
<P align=3Dcenter></FONT><B><FONT face=3DArial=20
color=3D#800080>Dates:</FONT><FONT face=3DArial=20
color=3D#ff0000> </FONT></B><FONT face=3DArial=20
color=3D#ff0000>May 7-8, 2007 (HSDD) <BR>May =
9-10, 2007=20
(AHSSP)</P></FONT><FONT face=3DArial =
color=3D#800080>
<P align=3Dcenter><B>Location:</B></FONT><FONT =
face=3DArial=20
color=3D#ff0000> Sheraton Hotel, Framingham,=20
MA</P></FONT><FONT face=3DArial color=3D#800080>
<P align=3Dcenter><B>Cost:</B></FONT><FONT =
face=3DArial=20
color=3D#ff0000> $1,195 each two-day =
course<BR>$25=20
discount with promo code: NL47</P></FONT><FONT=20
face=3DArial color=3D#800080>
<P align=3Dcenter></FONT><B><FONT face=3DArial=20
color=3D#800080>How to register:</FONT><FONT =
face=3DArial=20
color=3D#ff0000> <A=20
=
href=3D"http://www.regonline.com/BostonHSDD";><FONT=20
color=3D#ff0000>Sign Up =
Here!</FONT></A></FONT></B></P>
<P> </P></TD></TR></TBODY></TABLE>
<P class=3Dbodytxt><FONT face=3DVerdana =
size=3D2>Questions &=20
Comments: All students who attend our </FONT><FONT=20
face=3DVerdana color=3D#ff0000 size=3D2><A=20
href=3D"http://www.sigcon.com/seminars.htm";>High-Speed =
Digital=20
Design</A></FONT><FONT face=3DVerdana size=3D2> =
seminars have the=20
opportunity to talk directly with Dr. Johnson about =
signal=20
integrity issues.</FONT><FONT face=3DArial =
color=3D#ff0000=20
size=3D4></P></FONT><FONT face=3DArial color=3D#ff0000 =
size=3D4>
<HR>
</FONT><FONT face=3DVerdana color=3D#000000 =
size=3D2><FONT=20
face=3DArial color=3D#ff0000 size=3D3>
<P> </P>
<P></P><!--this is the copyright table at the bottom =
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<TBODY>
<TR>
<TD width=3D"100%">
<P align=3Dcenter><FONT face=3DVerdana =
color=3D#999999=20
size=3D2>If you have an idea that would make a =
good topic=20
for a future newsletter, <BR>please send it to =
<A=20
href=3D"mailto:info03@xxxxxxxxxx";><FONT=20
=
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color=3D#999999>.=20
<P align=3Dcenter>To subscribe to this list send =
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=
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<BR>with 'unsubscribe' in the subject field.=20
<P align=3Dcenter>Newsletter Archives at <A=20
style=3D"TEXT-DECORATION: none"=20
=
href=3D"http://www.sigcon.com/publications.htm";><FONT=20
color=3D#999999>www.sigcon.com</A><BR><A=20
style=3D"TEXT-DECORATION: none"=20
=
href=3D"http://www.sigcon.com/copyright.htm";><FONT=20
color=3D#999999>© Copyright 2007, Signal =
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