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March 2000

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Subject:
From:
"Misner, Bruce" <[log in to unmask]>
Reply To:
TechNet E-Mail Forum.
Date:
Thu, 16 Mar 2000 07:11:09 -0600
Content-Type:
text/plain
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text/plain (154 lines)
Enough. 30u Inches of Au IS NOT enough to embrittle solder joints. I've done
it on space flight hardware for years in the 1980's and have performed every
test, environmental screen and evaluation imaginable with no detriment and
have satisfied NASA and the Air Force.  Satisfy your QA with an MRB, accept
the boards, send a SCAR to the vendor, save your schedule and save your
headache for something real. Next Topic.

> ----------
> From:         Paul Klasek[SMTP:[log in to unmask]]
> Reply To:     TechNet E-Mail Forum.;Paul Klasek
> Sent:         Wednesday, March 15, 2000 8:04 PM
> To:   [log in to unmask]
> Subject:      Re: [TN] ??: [TN] Gold Removal
>
> Oh, gee, ehm, Ryan, mate, close, not sure if enough :
> 1
> Steve's maths ?(sorry Steve, you ARE one of the LEGENDS):
> "nearly" 75u" = 1.875um (or close enough);
> is NOT in line with ITRI's recommended 1.5um ceiling :
> me the coward never had guts to digest even 1um on soldered pads .
> I'll give you; with latest pad size trends (smaller); you may creep touch
> higher,
> but i do know if i'd got totally stoned and placed more than 1umAu on
> specs,
> my fellow in QA would be after my skin .
> Besides, Tim 's been just quizzing me where the hell do i squeeze 0.5um
> from
> flush;
> whining bitterly all he gets from his fabs is 0.25um tops on flash .
> Record i MEASURED on flash was some 0.8um,
> so i presume it's my turn in Tim's shoes :
> Where would you get saturation's which throws 75u" on Ni ?
> Presume only academic maths ?
>
> And the bible talks, i think (?) about 4% , not 3,
> but i won't be making scenes about that one
> (less is better, almost, hahaha)
>
> And NiAu (0.5umAu average = 20u") costs us less than HASL .
>
> Getting gold ears from all this off hip traffic ;
> getting dark here too: Inge : deleted some dozen methaned messages today !
>
> All in good humor Ryan , ok ?, just let's retain the functionality.
>
>
> Paul
>
> -----Original Message-----
> From: Ryan Grant [mailto:[log in to unmask]]
> Sent: Thursday, 16 March 2000 10:47
> To: [log in to unmask]
> Subject: Re: [TN] ??: [TN] Gold Removal
>
>
> I agree with this.  Do the math.  If a five mil stencil is used, and the
> component leads are NOT gold plated, the board gold thickness can reach
> nearly 75 micro inches before the percentage of gold in the joint reaches
> the magical number of 3%.  Below 3%, gold is not shown to induce
> embrittlement.  If you are soldering to BGA balls, there is even more Tin
> to
> dilute the gold, so the gold thickness can be even thicker.  The reason
> for
> the 5 to 8 micro inches of gold thickness is, that is the MINIMUM needed
> to
> prevent oxidation of the nickel.  Thicker gold is more expensive in terms
> of
> processing and material cost, and it is unnecessary, so why do it?
>
> Of course, if I buy a new stereo, and it has a scratch on it, I'll take it
> back.  Functionality be damned.  Rick can do the same with his boards.
>
> Ryan G.
>
> > -----Original Message-----
> > From: Timothy Reeves [SMTP:[log in to unmask]]
> > Sent: Wednesday, March 15, 2000 3:08 PM
> > To:   [log in to unmask]
> > Subject:      Re: [TN] ??: [TN] Gold Removal
> >
> > Does anyone agree with this? I hope not.
> >
> > > ----------
> > > From:         Jonathan A Noquil
> > > Sent:         Tuesday, March 14, 2000 15:57
> > > Subject:      Re: ??: [TN] Gold Removal
> > >
> > > Higher gold thickness does not affect
> > > reliability (solderability),
> >
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