Ioan,

The addition of some amount of copper and other proprietary dopants to
pure tin can produce an alloy with a significantly lower copper
dissolution rate when compared to SAC305 or SAC405.

Regards,
Karl Sauter


Tempea, Ioan wrote On 09/22/06 12:49,:

>Why does this happen anyways?  Is it due to the higher Sn content? In this case shouldn't SN100C be even tougher? Why did I hear then that SN100C will be OK where SAC is too agressive?
>
>Thanks,
>
>Ioan
>
>-----Original Message-----
>From: Leadfree [mailto:[log in to unmask]]On Behalf Of Karl Sauter
>Sent: Thursday, September 21, 2006 4:05 PM
>To: [log in to unmask]
>Subject: Re: [LF] FW: [TN] Dissolving copper hole wall using lead free
>HASL?
>
>
>Dave,
>
>That depends upon your assembly profile and peak temperature, as well as
>starting copper thickness in the plated-through hole.  At temperatures
>higher than 230 C a SAC alloy will dissolve copper more than 3x as fast
>as eutectic tin-lead at 230 C.  Especially at the knee of a plated
>through hole, a pin soldered-in with SAC alloy may barely allow 1 rework
>depending upon your minimum copper at the knee of the hole requirements
>for finished assemblies.
>
>Regards,
>Karl Sauter
>
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--
Karl Sauter             Senior Staff Engineer, Engineering Technologies
                        Sun Microsystems Inc.
                        Office: (650) 786-7663 / x87663
                        E-mail: [log in to unmask]

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