wait till they tell you the truth about minimum annular and it's
effect on post interconnect reliability.
At 08:45 AM 1/21/2010, Bev Christian wrote:
>Jon,
>Sorry about that. Hope you still love your parents. :)
>Bev
>
>-----Original Message-----
>From: TechNet [mailto:[log in to unmask]] On Behalf Of Roberts, Jon (SA-1)
>Sent: Thursday, January 21, 2010 11:35 AM
>To: [log in to unmask]
>Subject: Re: [TN] Antimony in solder
>
>Where antimony is reference in IPC and I have one question related to
>the ongoing testing.
>
>Antimony is reference in:
>
>IPC-J-Std-001D in Par 3.2 uses the letter A and B after the three for
>solder alloys. The letter ties back to IPC-J-Std-006 Par 3.3.1 through
>3.3.3 for maximum amount of antimony.
>
>Question:
>
>Does the testing included temperature changes with extreme cold
>condition?
>
>Just curious.
>
>Technet discussions are extremely valuable to myself. Finding out the
>purpose of antimony to help prevent tin pest is not real is like finding
>out your parents lied to you all those years.
>
>I thank all of you for your expertise, Jon
>
>
>
>-----Original Message-----
>From: TechNet [mailto:[log in to unmask]] On Behalf Of Graham Collins
>Sent: Thursday, January 21, 2010 5:23 AM
>To: [log in to unmask]
>Subject: Re: [TN] Antimony in solder
>
>Technet is a great resource, thanks Dave, Mike, and everyone else who
>has chimed in here.
>
>If I'm understanding what has been said here, I am concluding about
>Sn63Pb37Sb.4A the following:
>
>1) based on the responses it does not sound like a popular alloy choice
>(nobody here has said "I use it because...")
>2) Adding antimony improves wetting
>3) tribal knowledge suggests other benefits, such as avoidance of Tin
>Pest, not substantiated by data.
>
>Am I missing or misunderstanding anything?
>
>regards,
> - Graham
>-----Original Message-----
>From: TechNet [mailto:[log in to unmask]] On Behalf Of David D. Hillman
>Sent: Wednesday, January 20, 2010 7:45 PM
>To: [log in to unmask]
>Subject: Re: [TN] Antimony in solder
>
>Hi folks! Just a couple of comments to add to the discussion. Antimony
>gives solder a number of beneficial characteristics including wetting
>and
>tin pest resistance as has been mentioned in our TechNet discussion. Bev
>
>Christian and I published a paper at the 2006 SMTAI Conference on tin
>pest
>which did indeed show that the potential of tin pest in a solder joint
>is
>not very probable. In fact , I am still monitoring those test assemblies
>
>and after 4.5 years, we still have no tin pest phenomena occurring (I
>gave
>an update of the investigation at the 2008 SMTAI Conference). As part of
>
>the 2006 paper/ investigation, I pulled a bunch of literature references
>
>which turned into a very fascinating tour of the industry solder
>specification evolution. Antimony was part of several industry research
>projects by Becker and Borneman in the late 1950's. Their data
>(including
>the role of antimony) was part of the basis for the ASTM and QQ-S-571
>specification requirements. When the QQ-S-571 specification was replaced
>
>by the IPC-JSTD-006 specification, there was a huge debate on the
>necessity of antimony and unfortunately most of discussions were based
>on
>tribal knowledge instead of looking at the original investigation
>data/results. Some very good summary papers were published by the
>International Tin Research Institute (Thwaites, McKay, etc) which
>allowed
>the industry committees to work out a compromise of "violent agreement".
>
>The literature search was a great demonstration of how industry
>investigation results evolve over time and sometimes get
>positively/negatively mutated in ways the never imagined.
>
>Dr. Chris Hunt and Dr. William Plumbridge have published some very good
>papers in the last couple of years expanding our knowledge of the tin
>pest
>phenomenon.
>
>Dave Hillman
>Rockwell Collins
>[log in to unmask]
>
>
>
>
>Mike Fenner <[log in to unmask]>
>Sent by: TechNet <[log in to unmask]>
>01/20/2010 11:19 AM
>Please respond to
>[log in to unmask]
>
>
>To
>[log in to unmask]
>cc
>
>Subject
>Re: [TN] Antimony in solder
>
>
>
>
>
>
>There are many myths about tin pest, some of them you really want to be
>true
>like: the reason Napoleon lost against the Russians was that the French
>Uniform buttons were made of tin, they succumbed to tin pest and their
>trousers all fell down......
>Our European office gets about 3 tin pest questions a year, but it never
>
>is.
>The failures are due to more boring things like poor wetting,
>inappropriate
>joint design and so on. Or sometimes people report tin pest when they
>mean
>tin whiskers.
>NPL here did look into this quite thoroughly. You can get their report
>on
>line, a very nice piece of science. More dramatically satisfying you can
>
>see
>video from their research showing tin pest eating a lump of tin. They
>concluded tin pest was not a worry and so far as I know there has NEVER
>been
>a proven case of tin pest in electronics. Presence or absence of 0.X%Sb
>in
>tin is not significant compared to ~40% Pb. Possibly the Sb made the
>solder
>harder/stronger, but more likely other changes were made as indicated
>above.
>
>Regards
>
>Mike
>
>
>
>
>
>Mike Fenner, Technical Manager
>Indium Corporation
>Europe
>
>Mob: + 44 7810 526 317
>Skype: mike.fenner
>Tel: + 44 1908 580 400
>Fax: + 44 1908 580 411
>www.indium.com
>
>---------------------
>
>Indium Corporation
>Incorporated in New York, USA
>Registered office: (Not for correspondence)
>77-97 Harpur Street, Bedford , UK
>Registered number: fc16473
>
>* Please think before you print
>
>-----Original Message-----
>From: TechNet [mailto:[log in to unmask]] On Behalf Of Roberts, Jon (SA-1)
>Sent: Wednesday, January 20, 2010 4:35 PM
>To: [log in to unmask]
>Subject: Re: [TN] Antimony in solder
>
>I was always trained during my early years working with the Cat A under
>the WS6536, DoD Std 2000, etc days that Bev stated to reduce tin pest.
>I was informed that during the cold war in the 70's that line of radars
>were installed in the northern part of Canada to detect incoming
>missiles attacks. The extreme cold temperature caused solder failures
>related to tin pest or was attributed to tin pest. I believe my Cat A
>without question. Anyone else remember being told that? I am one of the
>older ones here. Jon
>
>-----Original Message-----
>From: TechNet [mailto:[log in to unmask]] On Behalf Of Bev Christian
>Sent: Wednesday, January 20, 2010 9:56 AM
>To: [log in to unmask]
>Subject: Re: [TN] Antimony in solder
>
>Graham,
>I think it was historically added because of a fear of tin pest. Which
>is weird since lead is an excellent deterrent to tin pest.
>Bev
>
>-----Original Message-----
>From: TechNet [mailto:[log in to unmask]] On Behalf Of Nigel Burtt
>Sent: Wednesday, January 20, 2010 10:51 AM
>To: [log in to unmask]
>Subject: Re: [TN] Antimony in solder
>
>Antimony affects wetting speed
>
>Useful reference here:
>
>http://www.kester.com/en-us/documentation/EffectsofMetallicImpurities.pd
>f
>
>Nigel
>
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