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May 2017

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From:
"Stadem, Richard D." <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, Stadem, Richard D.
Date:
Wed, 17 May 2017 14:20:24 +0000
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I wouldn’t know. Our IT department forbids us from looking at those. No political forums, no online news sites, no medical insurance FAQs, nothing with the words “You’ll never believe what the cameraman saw”……..



From: Douglas Pauls [mailto:[log in to unmask]]

Sent: Wednesday, May 17, 2017 9:17 AM

To: TechNet E-Mail Forum; Stadem, Richard D.

Subject: Re: [TN] IMC Formation Thickness in OSP



But Dean, it's on the internet.  They can't put anything on the internet that isn't true.  I heard that on the internet......





Doug Pauls

Principal Materials and Process Engineer

Rockwell Collins



On Wed, May 17, 2017 at 9:14 AM, Stadem, Richard D. <[log in to unmask]<mailto:[log in to unmask]>> wrote:

Steve, please don’t bandy that stuff about. If my operators see that they’ll all want some ASAP. Imagine not having those pesky cords that are always knocking over their pop cup on the ESD bench, LOL!



From: Steve Gregory [mailto:[log in to unmask]<mailto:[log in to unmask]>]

Sent: Wednesday, May 17, 2017 9:07 AM

To: TechNet E-Mail Forum; Stadem, Richard D.

Subject: Re: [TN] IMC Formation Thickness in OSP



Hey Dean,

You liked those ROHS compliant foot straps so much, I know you'll just love the wireless wrist straps! At least they're only $4.00.



http://www.batteryspace.com/cordlesswriststrap--staticdissipativewithoutgroundingcord.aspx

Steve



On Wed, May 17, 2017 at 7:44 AM, Stadem, Richard D. <[log in to unmask]<mailto:[log in to unmask]><mailto:[log in to unmask]<mailto:[log in to unmask]>>> wrote:

I could not agree with you more, Dave!

What a lot of people do not understand also is that IMC formation is self-limiting. Rework temperatures do NOT “double the thickness of the IMC and therefore reduces reliability by half” as one solder company’s PhD stated recently when attempting to sell low-melting –point solder alloys. IMC thickness normally has little effect on reliability.



We in the electronics industry have to constantly beware of hucksters trying to make a buck with “easy” technical solutions, only to find you never get something for nothing, and sometimes you get nothing for something more, such as those green RoHS-compliant ESD footstraps for $49 per pair (still laughing and stepping down from soapbox also).

Odin



From: David Hillman [mailto:[log in to unmask]<mailto:[log in to unmask]><mailto:[log in to unmask]<mailto:[log in to unmask]>>]

Sent: Wednesday, May 17, 2017 8:21 AM

To: Stadem, Richard D.

Cc: TechNet E-Mail Forum

Subject: Re: [TN] IMC Formation Thickness in OSP



Hi Dean - good summary! There is currently a soldering iron manufacturer (who shall remain nameless) who is claiming their system manages the solder joint creation making the "ideal" IMC for a reliable joint. I have requested a copy of the data or research conducted on how the "ideal" IMC for solder joint integrity was derived and am still awaiting the information. I think we are causing some unnecessary waste of industry resources  many times with the topic of IMC comes up. Ok, I'll get off my soap box!



Dave



On Wed, May 17, 2017 at 7:29 AM, Stadem, Richard D. <[log in to unmask]<mailto:[log in to unmask]><mailto:[log in to unmask]<mailto:[log in to unmask]>><mailto:[log in to unmask]<mailto:[log in to unmask]><mailto:[log in to unmask]<mailto:[log in to unmask]>>>> wrote:

Most IMC failures are actually design issues related to delta CTEs between components and substrates, and to varying degrees. I respect the challenge you have of summarizing the perfect storm of these design issues, alloy factors (including nucleation and brittleness), aging, and incorrect or abusive solder joint processes (including rework)  that could contribute or lead to catastrophic SJ failure.



And yet, we all manage to do this every day in this industry.

Dean



-----Original Message-----

From: TechNet [mailto:[log in to unmask]<mailto:[log in to unmask]><mailto:[log in to unmask]<mailto:[log in to unmask]>><mailto:[log in to unmask]<mailto:[log in to unmask]><mailto:[log in to unmask]<mailto:[log in to unmask]>>>] On Behalf Of David Hillman

Sent: Wednesday, May 17, 2017 7:16 AM

To: [log in to unmask]<mailto:[log in to unmask]><mailto:[log in to unmask]<mailto:[log in to unmask]>><mailto:[log in to unmask]<mailto:[log in to unmask]><mailto:[log in to unmask]<mailto:[log in to unmask]>>>

Subject: Re: [TN] IMC Formation Thickness in OSP



Hi TechNet! I was holding off to see what folks posted. My question is "why does it matter?". An industry colleague and I are collaborating on a paper that covers "industry soldering myths" and intermetallic compound (IMC)  failure is right at the top of the list. Its a true statement that IMCs are brittle but, as an industry, we seem to translate/proliferate that statement into a solder joint defect. There are very very very few industry reports/publications of solder joint integrity failures due to IMC in product use environments. There are tons of reports of IMC failures created because of grossly incorrect or abusive solder joint processes which isn't the same thing. Victor - my suggestion is to focus on having a correct soldering process using acceptable time/temperature parameters regardless if its the initial soldering process or a rework activity. If the solder process is correct, whatever the IMC thickness turns out to be, it will be acceptable.



Dave Hillman

Rockwell Collins

[log in to unmask]<mailto:[log in to unmask]><mailto:[log in to unmask]<mailto:[log in to unmask]>><mailto:[log in to unmask]<mailto:[log in to unmask]><mailto:[log in to unmask]<mailto:[log in to unmask]>>>



On Tue, May 16, 2017 at 4:58 PM, George Wenger <[log in to unmask]<mailto:[log in to unmask]><mailto:[log in to unmask]<mailto:[log in to unmask]>><mailto:[log in to unmask]<mailto:[log in to unmask]><mailto:[log in to unmask]<mailto:[log in to unmask]>>>>

wrote:



> Victor,

>

> I haven't seen and TechNetter responses but I'll give you my two cents.

> The

> IMC thickness numbers you heard sound much too high.  I think the IMC

> thickness should be half as thick as those numbers.

>

>

> Regards,

> George Wenger

>

>

>

> -----Original Message-----

> From: TechNet [mailto:[log in to unmask]<mailto:[log in to unmask]><mailto:[log in to unmask]<mailto:[log in to unmask]>><mailto:[log in to unmask]<mailto:[log in to unmask]><mailto:[log in to unmask]<mailto:[log in to unmask]>>>] On Behalf Of

> [log in to unmask]<mailto:[log in to unmask]><mailto:[log in to unmask]<mailto:[log in to unmask]>><mailto:[log in to unmask]<mailto:[log in to unmask]><mailto:[log in to unmask]<mailto:[log in to unmask]>>>

> Sent: Tuesday, May 16, 2017 8:35 AM

> To: [log in to unmask]<mailto:[log in to unmask]><mailto:[log in to unmask]<mailto:[log in to unmask]>><mailto:[log in to unmask]<mailto:[log in to unmask]><mailto:[log in to unmask]<mailto:[log in to unmask]>>>

> Subject: [TN] IMC Formation Thickness in OSP

>

> Fellow TechNetters:

>

>    What is the acceptable guideline for IMC Formation thickness on OSP

> after

> 2x rework..   IPC-4555 is still pending.  I've heard of 3-5 microns on

> first

> pass and 5-10 microns on 2x RW.   All comments/suggestions welcomed.

>

> Victor,

>







--

Steve Gregory

Kimco Design and Manufacturing

Process Engineer

(208) 322-0500 Ext. -3133<tel:%28208%29%20322-0500%20Ext.%20-3133>



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