Larry. How are the interconnections performing now? My first reaction is
'Ouch!', but can't specify the metalurgy for you.

Pete Duncan





                    "Jindra,
                    Larry"               To:     [log in to unmask]
                    <Larry.Jindra        cc:     (bcc: DUNCAN Peter/Asst Prin Engr/ST Aero/ST Group)
                    @TRW.COM>            Subject:     [TN] ENIG in flex layers
                    Sent by:
                    TechNet
                    <[log in to unmask]
                    ORG>


                    05/25/01
                    03:16 AM
                    Please
                    respond to
                    "TechNet
                    E-Mail
                    Forum.";
                    Please
                    respond to
                    "Jindra,
                    Larry"






Our rigid/flex vendor deposited immersion gold over electroless nickel on
internal 1 oz copper flex layers prior to lamination of a rigid-flex-rigid
board.  Our intent was to have ENIG finish only on the exposed connector
pads on the one end of the rigid/flex (6 layers).  Instead, the ENIG is on
the pads, on the flex, and continues on in internal to the other rigid
portion of the circuit board (10 layers).

I have concerns about the durability of the flex and the via stackup in the
10 layer rigid section, which now has nickel on layers 3 & 8.  Am I just
paranoid, or am I in trouble?

> Larry Jindra
> mailto:[log in to unmask]   ph (858) 592-3424   fax (858) 592-3940
>

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