Jeff:
What is the Amkor test and guarantee?
John Lynch
ON Semiconductor
Jeff Cannis wrote:
>
> Just as important,
>
> In the absence of an industry standard test method, how does one prove that a
> coating is whisker free? There have been a number recent papers proposing
> various test conditions, but none have been adopted by any industry group. Any
> data presented on whisker growth, or suppression, is somewhat arbitrary until we
> all agree on a valid method to accelerate whisker growth.
>
> Regards,
> Jeff Cannis
> Amkor Technology
>
> Kirk D Mueller <[log in to unmask]> on 10/05/2000 09:41:49 AM
>
> Please respond to "Leadfree Electronics Assembly E-Mail Forum."
> <[log in to unmask]>; Please respond to Kirk D Mueller
> <[log in to unmask]>
>
> To: [log in to unmask]
>
> cc:
>
> Subject: Re: [LF] Tin whiskers on tin-dipped terminations
>
> OK, how does one inhibit tin whisker formation in a pure tin coating?
>
> Yun Zhang <[log in to unmask]>@IPC.ORG> on 10/05/2000 09:08:32 AM
>
> Please respond to "Leadfree Electronics Assembly E-Mail Forum."
> <[log in to unmask]>; Please respond to [log in to unmask]
>
> Sent by: Leadfree <[log in to unmask]>
>
> To: [log in to unmask]
> cc:
> Subject: Re: [LF] Tin whiskers on tin-dipped terminations
>
> I concur with Mr. Petit on a number of things:
> One does not have to use SEM to see a long whisker (e.g., length > 50
>
> ------------------------------------------------------------------------
>
> µm).
> So long as one learned to know what to look for, it is not a difficult
> task
> to find a relatively long one. It is those tiny ones (< 5 µm in both
> length
> and diameter) that are most challenging, and would need a SEM with high
> magnifications to see them.
> Whiskers do not readily grow on all substrates. Brass is one of the
> worse,
> pure copper is one of the best substrates.
> The electronic industry can come up with reliable tin coatings to
> replace
> tin/lead coatings.
>
> I would also like to add that there are ways to minimized the propensity of
> whisker formation besides using a barrier layer and reflow. The kinetics
> of
> whisker growth from the tin layer may be effectively controlled.
>
> Regards,
>
> Yun Zhang
> Lucent Technologies
> Electroplating Chemicals and Services
>
> [log in to unmask] on 10/05/2000 03:02:47 AM
>
> Please respond to "Leadfree Electronics Assembly E-Mail Forum."
> <[log in to unmask]>; Please respond to [log in to unmask]
>
> To: [log in to unmask]
> cc: (bcc: Yun Zhang/ECSDOMAIN)
>
> Subject: Re: [LF] Tin whiskers on tin-dipped terminations
>
> Tin whiskers can be found by binocular microscope at X20 to X50 but
> confirmation that the visible protrusion is really a whiskers may
> require SEM observation as other plating defect may look as a
> whiskers.
>
> In the case of the component their are two issues about whiskers:
> what is the maximum length of such defect which is not giving any
> trouble;
> on a ceramic capacitor who cares about a 50µm whisker , even 100µm
>
> then come immediaytely the second issue :
>
> is the growth stopped for ever or is it a growing whiskers or a
> potentially growing one .
>
> It is true that whiskers do not grow on every base materials
> and i am confident the electronic industry can come to a reliable
> solution with tin coatings as replacement of tin-lead.
>
> regards
>
> L.Petit
> ST Microelectronics
>
> ______________________________ Reply Separator
> _________________________________
> Subject: Re: [LF] Tin whiskers on tin-dipped terminations
> Author: gordon.davy ([log in to unmask]) at internet
> Date: 10/4/00 11:24 PM
>
> James Canner of Murata stated that he has ceramic capacitor chips with
> electroplated tin terminations that are over ten years old that have "no
> visible tin whisker formation." There was a big discussion at Works 2000
> about tin whiskers. One thing that I learned is that you have to use
> scanning electron microscopy to look for them. While they may grow to a
> length of several millimeters, the diameter is on the order of a micrometer
> - close to the diffraction limit for optical microscopy. I am sure that
> some
> of the tin whisker experts must be subscribed to the leadfree forum, and I
> would think that someone would be interested in looking for whiskers on a
> ten-year-old tin plated surface.
>
> Gordon Davy
>
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