Well it is a chemical term. We have dis solution over here and dat
solution over dere..................
Somebody help me......................
Doug Pauls
From: Inge Hernefjord <[log in to unmask]>
To: <[log in to unmask]>
Date: 02/03/2012 02:55 PM
Subject: Re: [TN] R: [TN] Cu - dissolution and IMC growth rate
Sent by: TechNet <[log in to unmask]>
Dissolution (why do we use that word?I prefer diffusion) of various metals
in solder melts has been done for cent uries, so I have nothing new. What
I
found unexpected was the mirror-like diagrams showing Gold, Silver, Copper
and some others dissolution in Sn6040. Probably following arrhenius's
law.
You must see it yourself, so I send it to Steve and his dino.
I read some interesting facts in one of the ASTM Handbooks. "Handbooks" !1
This one is so gross and heavy, that you need car lift. If you drop that
volume, seismographs all around will jump.
Inge
On 2 February 2012 23:58, SALA GABRIELE <[log in to unmask]> wrote:
> Hi,
>
> What I found on IPC Standards, just few paragraphs on
> IPC-HDBK-001,(Dec-2000)
>
> 4.1.7.2 Intermetallic Layers
> 4.1.7.2.1 Intermetallic Growth Rates
>
> As Dave says, plenty of information (Papers) are available about Copper
> Dissolution phenomena and IMC behaviours at different temperatures and
> Alloys. With Reflow,Wave and Rework Processes.
> Also on web, if lucky, by googling you can find plenty of helpful infos.
>
> Regards
>
> Gabriele
>
>
> -----Messaggio originale-----
> Da: TechNet [mailto:[log in to unmask]] Per conto di David D. Hillman
> Inviato: giovedì 2 febbraio 2012 23.02
> A: [log in to unmask]
> Oggetto: Re: [TN] Cu - dissolution and IMC growth rate
>
> Hi Stewart - I would recommend that before you launch into a SAC305
copper
> dissolution project that you investigate the published data as there has
> been a tremendous volume of work in that area already. Sources in my
> references include:
>
> - a number of papers presented in the IPC APEX and SMTAI conferences in
> the 2005-2012 time frame
> - NPL (Dr. Chris Hunt and team) did a great study on dissolution rate
> - Craig Hamilton and the folks from Celestica have some great
publications
> on copper dissolution
> - the NASA DoD report has copper dissolution data for SAC305 and SN100C
> solder alloys (the report is on the web)
>
> Your question on "how thick can IMC get before we have cracking issues"
is
> a good question but the reality is that the number of IMC cracking
issues
> published can be counted on one hand. Using industry typical soldering
> process, either tin/lead or leadfree solder alloys, you need to severely
> abuse the process parameters to get into those types of situations.
> Published data by Thwaites and Klein Wassink covers the IMC topic. There
> is no IPC standards on copper dissolution or IMC thickness that I am
aware
> of.
>
> Good luck with the effort.
>
> Dave Hillman
> Rockwell Collins
> [log in to unmask]
>
>
>
>
> Stewart McCracken <[log in to unmask]>
> Sent by: TechNet <[log in to unmask]>
> 02/02/2012 04:11 AM
> Please respond to
> TechNet E-Mail Forum <[log in to unmask]>; Please respond to
> Stewart McCracken <[log in to unmask]>
>
>
> To
> <[log in to unmask]>
> cc
>
> Subject
> [TN] Cu - dissolution and IMC growth rate
>
>
>
>
>
>
> Fellow Technetters,
>
> We are going to be involved in a project this year looking at rates of
Cu
> dissolution and IMC layer growth during soldering processes (including
> rework).
> At this stage, I would like to ask the wider community whether anybody
has
> or knows of "rules of thumb", or published data etc. which describes
rates
> of dissolution and rates of IMC layer growth?
>
> A little more specifically, based on a SAC305 alloy system, and using an
> Immersion Silver or OSP PCB finish, we are looking to develop our
> understanding of the following points:
>
> 1. IMC growth (microns) for SAC305 solder as a function of time exposure
> (seconds) above 230C
> 2. Cu dissolution (microns) for SAC305 solder as a function of time
> exposure (seconds) above 217C
> 3. Does anyone work to a defined critical threshold (in terms of max IMC
> thickness) above which PCB functional integrity is considered to be
> undermined?
> 4. Does anyone work to a defined critical threshold (in terms of min Cu
> thickness) below which PCB functional integrity is considered to be
> undermined?
> 5. Are there IPC or other standards covering these items?
>
> I would be extremely grateful for your input, and would be very happy to
> share results of the experimental programme which we will undertake
later
> this year.
>
> Thanks and kind regards,
>
> Stewart
>
> Stewart McCracken
> MCS Ltd.
> Centre House
> Midlothian Innovation Centre
> Roslin
> Midlothian
> EH25 9RE
> U.K.
>
> t. +44 (0)131 440 9090
> m. +44(0)7711 541735
> e. [log in to unmask]
> w. www.themcsgroup.co.uk
>
>
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