You are very welcome Raye,
And if you do have a problem once in a while, I'm sure we can be of
help. After all that is what we do :-).
Best regards,
Vladimir
On Fri, 2 Mar 2012 11:32:47 -0800, "Rivera, Raye" <[log in to unmask]> wrote:
Hi Vladimir,
>
> Thanks for the reply. Your point is well taken. Not much good having
> robust solder joints if the device fails. Best regards,
> Raye Rivera
> QA Manager * Canoga Perkins * 818-678-3872 * [log in to unmask]
>
> -----Original Message-----
> From: vladimir Igoshev [mailto:[log in to unmask]] Sent:
> Thursday, March 01, 2012 4:00 PM
> To: TechNet E-Mail Forum; Rivera, Raye
> Subject: Re: [TN] BGA Reverse Backwards Compatibility
>
> Hi Raye,
>
> From the metallurgical point of view there is not much of the
> difference whether it's SAC BGAs with Sn-Pb or vice versa.
>
> However!!! When one puts Sn-Pb BGA through a Pb-free profile, long
> term reliability of the component itself might be jeopardized.
> Vladimir
>
> SENTEC Testing Laboratory Inc.
> 11 Canadian Road, Unit 7.
> Scarborough, ON M1R 5G1
> Tel: (416) 899-1882
> Fax: (905) 882-8812
> www.sentec.ca
>
> -----Original Message-----
> From: "Rivera, Raye" <[log in to unmask]>
> Sender: TechNet <[log in to unmask]>
> Date: Thu, 1 Mar 2012 12:11:12 To: <[log in to unmask]>
> Reply-To: TechNet E-Mail Forum <[log in to unmask]>,
> "Rivera, Raye"
> <[log in to unmask]>
> Subject: [TN] BGA Reverse Backwards Compatibility
>
> Hello TechNet Gurus.
>
> I have seen lots of discussion and studies on the reliability of
> using BGAs with SAC solder balls on an assembly with SnPb paste. Many
> people are interested in this topic because of backwards
> compatibility issues when SnPb BGAs aren't available. At the risk of
> oversimplifying a complex topic, I understand this can be successful
> using a backward compatibility thermal profile such as the one shown
> on Figure 8-20 of IPC-7095B to ensure complete melting of both types
> of solder. Of course we must take care that the profile does not
> exceed the temperature limitations of the SnPb paste.
>
> Is anyone aware of any study done on the reverse situation? That is,
> SnPb BGAs used with SAC solder paste and a SAC thermal profile? I
> would think it would be at least as reliable as the above situation.
> We definitely get complete melting and the temperature profile is
> correct for the SAC solder paste chemistry so we are not as concerned
> about holding a narrow process window.
>
> This is not just academic curiosity on my part. We have some
> prototype boards built with SnPb BGAs SAC paste, and SAC profile.
> They are not for sale to customers, but some of our engineers are of
> the opinion that any mixed process joint is suspect. I'd like to find
> some data on the topic.
>
> I hope everyone is enjoying Apex.
>
> Best regards,
> Raye Rivera
>
> QA Manager * Canoga Perkins
> 20600 Prairie Street * Chatsworth * CA 91311-6008
> 818-678-3872 * [log in to unmask]
>
>
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